BMS Tropical Update 6/19/2017 12 PM CDT

As expected from last week, two areas of tropical trouble are trying to form in the Atlantic Basin. If both of these tropical systems manage to get named this week, it would be fairly rare as only three Atlantic hurricane seasons on record have had two concurrent named storms in June. Those years were 1909, 1959 and 1968, all of which turned out to be average to slightly above average hurricane seasons with a higher than average landfall rate across the U.S. This is in line with the general thinking of what could occur this Atlantic hurricane season.

Since last week, the National Hurricane Center  (NHC) has been watching these two disturbances. One of these has been centered north of the Yucatan Peninsula and has been labeled Invest 93L. The other disturbance is labeled Invest 92L and is currently located 325 miles ESE of Trinidad, moving rapidly toward the southern Windward Islands. In fact, for the first time ever for a tropical system, the NHC has begun issuing advisories for 92L before it is a depression or named storm and has also labeled the system “Potential Tropical Cyclone Two.” I talked about this possibility in my New Hurricane Products for 2017 Season blog post. The NHC is doing this because there is an immediate threat of tropical storm force winds to land, which, in this case, would be in the southern Windward Islands where the watches and warnings are in effect.

What is the forecast and worry for insurance industry this week?
“Potential Tropical Cyclone Two”
Potential Tropical Cyclone Two has a 90% chance of tropical development over the next two days. Early visible satellite imagery suggests the system is still an open wave and does not have a closed center of circulation, which is part of the criteria for storm naming by the NHC. My guess is that the NHC will wait to name the storm (Bret is the next storm name) until this afternoon when an Air Force reserve hurricane hunter aircraft is scheduled to investigate the potential tropical cyclone. Depending on what the aircraft finds, it could get a name. Regardless of whether the potential tropical cyclone gets a name, stormy conditions will be experienced in the southern Windward Islands. The forecast models are suggesting that after today the system will struggle to maintain itself as interaction with South America and increased wind shear will likely hamper any development in the second half of this week. This means the overall impact to the U.S. insurance industry is minimal at this time, and even if named, it would be a short lived tropical system.

Last Night ECMWF Ensemble Breakdown of disturbance two tracks and intensity

Invest 93L
Invest 93L also has a high chance of tropical development over the next two days with an 80% chance of development. The reason why the NHC has not issued advisories for this system is they currently feel the threat of tropical storm conditions is less severe and it could take a few days to produce strong winds over land. So overall, the difference between these two systems in terms of advisories is the immediate threat of tropical storm conditions to land is greater for Potential Tropical Cyclone Two. However, in the longer term Invest 93L has the higher likelihood to impact the insurance industry. This morning’s satellite imagery suggests that the low level center is decoupled from the deep tropical convection on the right (east) side of the storm.

Visible Satellite shows low level center is decoupled from the deep tropical convection on the right (east) side of the storm.

There is a chance it’ll never actually develop into a tropical cyclone as the wind shear over the next few days could hamper development.

ECMWF forecasted strong southwesterly wind shear associated with a trough aloft blowing t-storms away from surface center of Invest 93L inhibiting development. Also shown is the shear that could impact disturbance two.

However, later in the week this wind shear is likely to abate and formation of a named storm becomes more likely.

As always there is uncertainty in the development and final track of tropical systems. The GFS (American model) takes this system on a more northerly track towards Louisiana and even on some early weekend runs into the Florida panhandle. However, as I highlighted in my New Hurricane Products for 2017 Season blog post, the new GFS model this year is not the model to watch. The more reliable ECMWF (European model) takes 93L into southern Texas as indicated last week, so the model has been fairly consistent with the ideas Texas will see worse of the impacts in terms of tropical storm force winds if they develop.

At this time, almost all forecast models for 93L remain below hurricane strength. Regardless, deep tropical moisture will have far reaching effects along the Gulf Coast states, so heavy rainfall and flooding are currently the biggest threats to the insurance industry to areas that don’t handle a lot of rain well like New Orleans and Houston. Depending on the track,  5 inches of rain could easily fall as a sort of atmospheric river seems to be setting up along the Central Gulf Coast.

NOAA Weather Prediction Center showing much of the central gulf coast is expected to get 2 – 5″ of rain which is conservative in my opinion based on the sort of atmospheric river that seems to be setting up into the Central Gulf Coast with a possible poorly organized tropical disturbance.

 

 

New Hurricane Products for 2017 Season

Every year there are new tools and products that can help the insurance industry understand named storm risks.  In this write-up, I highlight some of these new tools and products for the 2017 hurricane season, which starts today.   For ideas on the type of activity that is expected this season please see my previous update here:  May Tropical Update issued May 15th.

Advisories Will Be Issued Before a Storm Is Named

The National Hurricane Center (NHC), which decides when a named storm gets a name, will issue advisories for tropical systems before the tropical system has a name. In these cases, these tropical systems will pose a threat of bringing tropical storm-force or hurricane-force winds to land areas within 48 hours. For decades these tropical disturbances have been called ‘Invests’, or areas of investigation, and for the last few years the NHC has been giving Invests forecasts related to the chance of formation within the next five days.

Currently some re/insurance contract language is directly related to named storm activity. However, the advisories for these tropical systems that will likely impact land could now lead to earlier activity in re/insurance contracts where coverage is triggered by storm warnings or watches, as the NHC would previously wait for a storm to be named before issuing such warnings or watches. In most cases, these types of named systems would be in a developing stage just off the U.S. coastline and would highlight not only the likelihood of genesis of a named storm, but the possible strength of winds along the coastline.

Hurricane Humberto in 2007 is a classic example of where the NHC would have likely issued watches and warnings before Humberto was named if it took place in 2017. Humberto strengthened into a hurricane in a 24 hour period. Source: AccuWeather Inc. & NOAA

Storm Surge Watches and Warnings Are Coming 

For the last several years, the NHC has made large improvements to storm surge forecasts from named storms.  In fact, the detailed Potential Storm Surge Flooding Maps now rival the high resolution flood model simulations that are becoming common in the insurance industry by various Cat Modeling vendors.  However, another tool that might help the insurance industry is that the NHC plans to release storm surge watch and warning graphics to provide further guidance on where the greatest threat to life and property from a named storm might be.   The insurance industry is all too familiar with the hazards and damaging storm surge that occur with a threatening named storm and this guidance can help pin point areas likely to be most impacted by storm surge.

New storm surge watch and warning product for 2017 hurricane season. Source: NHC

Earliest Reasonable Arrival of Tropical Storm-Force Winds Will Be Forecast

The NHC has always provided guidance as to the position and timing of the center of a named storm; however, to provide more added value, the NHC will now be directly forecasting when tropical storm-force winds will begin to affect land. This will allow the insurance industry to better understand when winds greater than 39 mph are expected, which should aid in allowing more time for an insured to apply preventative measures to mitigate risk from damaging storms. Above 39 mph, winds can make it difficult and even dangerous to be outside continuing preparations for a tropical storm or hurricane.

The IBHS has some helpful hints to reduce hurricane damage to homes and businesses.


The Cone of Uncertainty Will Be Smaller

Every year the NHC reviews the accuracy of their previous five seasons of hurricane forecasts.  This review suggests the forecasts are getting better, and with that, the average error in the NHC forecasts that make up that famous cone of uncertainty will result in a smaller cone and just maybe more certain hurricane forecasts for the 2017 season.  Track errors have gone down over the last 10 years and forecasts have gotten better.  In fact, since 2007, the size of the cone of uncertainty at 120 hours (or five days) has shrunk by more than 35%.  Since last year, the size of the cone at 120 hours has shrunk by more than 10%.

The shrinking cone of uncertainty. Source Brian McNoldy Univ. of Miami

Hurricane Model Wars

As long as I have been studying meteorology there have been wars among the various forecast models as to which model is the most accurate at forecasting named storm activity.  This war was brought into the public limelight after Hurricane Sandy in 2012, when the American Model [Global Forecast System (GFS)] falsely forecasted Sandy to track offshore, and the European ECMWF model correctly predicted Sandy to make landfall in New Jersey.  Just like the various hurricane products described above, the weather models themselves are under ongoing improvements.  One item to watch this hurricane season is the upgrade to the GFS model on July 12th.  As part of these upgrades, the NOAA asks forecasting divisions like the NHC to run performance tests.   Although the tests might suggest better temperature forecasts or precipitation forecasts for different areas of the globe, one area where the upgraded GFS shows deficient skill is with hurricane forecasting.   The report I have seen from the NHC suggests for the 2014-2016 retrospective runs, in comparison to the 2016 GFS model, the 2017 GFS showed a 9-10% degradation in track forecast skill at 48-72h in the Atlantic Basin.  In terms of intensity forecasting, the 2017 GFS showed degradations in intensity forecast skill at nearly every forecast interval out to 120 hours in the Atlantic Basin.  The new GFS model also indicated less run-to-run consistency.  It likewise showed little overall improvements in TC genesis forecasts for the Atlantic Basin.

Evaluation of the proposed 2017 GFS implementation done by the NHC in February 2017

Another troubling factor is that the GFS model will likely have other fallouts with the regional models, such as the HWRF and GFDL, and the statistical models such as the GFEX.

Here is the quote from the NHC about the upgrade to the GFS model:

“The loss of short- to medium-range TC track and intensity forecast skill for the Atlantic basin in the proposed 2017 GFS is unacceptable to the National Hurricane Center.  We are also concerned about the lack of testing of the downstream impact of the 2017 GFS on the regional hurricane models.  Therefore, we oppose this implementation.”

As the insurance industry watches all of the various hurricane forecast model runs to determine where a hurricane might track, it might be good to put a bit more weight in the ECMWF model this season.  However, the ECMWF will also be upgraded on July 11th and very few people know what these upgrades will do to its hurricane forecasting.

Detail of this model upgrade can be found here:

http://www.emc.ncep.noaa.gov/gmb/noor/GFS2017/GFS2017.htm

In an uncertain world, client-centric broking is vital, says BMS CEO Nick Cook, as he begins a visit to Australia

Last weekend’s global cyber attack reminded us all of the new threats and challenges brought by technology. To help our clients deal with them, BMS has a specialist cyber-risk team that provides effective advice before, during, and after any cyber incident. It is just one area where our insight and collaborative approach enable us to add value through risk management and education.

Hot on the heels of hiring Andrew Godden as our new CEO of BMS Australia, I’ll be joining our team in Sydney on Monday 22 May and visiting clients and markets throughout the week. The investment we are making in BMS Australia and Asia Pacific, based around the entrepreneurial culture we have created inside BMS, increases our reach amongst clients because it has helped us to attract the highest calibre of market-leading individuals to the team.

In Australia, our focus remains absolutely on our clients, particularly given the level of growth BMS Australia has recently experienced. We remain committed to our current wholesale strategy, supporting retail brokers in certain niche classes of business such as mining, sports and healthcare associations and general liability. We launched our Australian operation with the opening of our Sydney office in 2014 and the Melbourne office in 2016. To have been able to attract an industry leader of the calibre of Andrew Godden is testament to our team’s work in the region and to our ambitions.

Across Australia, we see many opportunities in the corporate arena to offer existing and new clients access to our broking services and industry-leading technology in an ever more complex business environment.

We believe in specialisation. Our Melbourne affinity business focuses on providing targeted advice and service to specialist interest groups. For example, to date, we have more than 500,000 healthcare professionals as clients through their associations. BMS is a vital link in assisting those associations to grow their membership.

BMS is an employee-owned business, committed to its independence for the long-term. Whilst the insurance market faces challenging conditions world-wide, our investment in new technology is creating opportunities.

The quality of our people is the reason for our success – and we are determined to keep hiring the best people to make certain our clients are getting the best possible advice and service.

May Tropical Update

Seasonal Hurricane Forecast Skill

Seasonal hurricane forecasts, with varying lead times, have been produced in the Atlantic basin since 1984 by the late Dr. Gray from Colorado State University (CSU).  Partly as a result of the early success of those forecasts, seasonal named storm forecasts are now a dime a dozen with many different research and operational groups making seasonal hurricane forecasts for tropical basins around the world.  Although there are some very brilliant minds making these forecasts, some might argue there has been little skill improvement over the last several years. The insurance industry is accustomed to using climatology to understand the risk of a U.S. landfalling hurricane.  This climatology also suggests, on average, the more active the overall Atlantic basin hurricane season is, the greater the probability of U.S. hurricane landfall which can be useful guidance to the insurance industry heading into the hurricane season. However, when it comes to seasonal landfall forecasts, really no skill has been demonstrated; this is ultimately what matters for the insurance industry.  In fact, there isn’t a forecast group that has skillfully predicted the current drought in major hurricane strikes over the last 11 years.

CSU Atlantic Basin wide hurricane forecasted and observed hurricanes with missed forecasted number shown.

CSU provides easy access to historical forecasts which allows for simple validation of there seasonal forecasts.  In a simple analysis, the CSU forecast has done fairly well with their April predictions when compared to using historic climatology (6.5 hurricanes per year) .  Fourteen CSU forecasts since 1995 have come within three hurricanes of the seasonal hurricane total in the Atlantic Basin.  On seven occasions, they have only missed the cumulative number by one.  They hit the mark in 2008.  Of course, CSU have posted a few wayward forecasts as well: 2005 (undershot the total by eight hurricanes) and 2012 (fell short by six hurricanes).

CSU Atlantic Basin wide major hurricane forecasted and observed hurricanes with missed forecasted number shown.

Regarding the major hurricane forecasts, CSU has made seven forecasts that failed to fall within two storms of the final tally. This should not obscure the fact that they’ve also posted four perfect forecasts of major hurricane occurrence and 13 others that approximated the seasonal total within one storm.
It is very easy for one to sit back and grade objective season hurricane forecasts like CSU, and there is no doubt a lot of work goes into the refinement of these forecasts each year. I am a firm believer that seasonal forecasts and even landfall forecasts will improve over time. Currently, many of these seasonal forecasts are statistical schemes which will inherently fail some years. There is some promise that a hybrid of statistical and dynamical forecast could be the future of seasonal hurricane forecasting.

https://www.gfdl.noaa.gov/hyhufs/

The Real Value – Landfall Forecasts

As mentioned, the real value to the insurance industry is in getting an accurate picture of potential landfalling storm activity. CSU issues probabilities for landfalling hurricanes across various regions of the U.S. This year, they are forecasting a 75% probability of a hurricane landfall. The probability of landfall for any one location along the coast is very low and reflects the fact that, in any one season, most U.S. coastal areas will not feel the effects of a hurricane no matter how active the individual season is. And, given the variation of exposure along the coast, providing accurate estimated insured loss ahead of season is very difficult if not impossible.
However, given the current state of the science of seasonal forecasting it is possible to provide guidance to which area of the coastline will see a higher than normal probability of landfall. This year, landfall forecasts may prove to be one of the more challenging years. This is due to the large amount of uncertainty of many of the climate forcers used to predict Atlantic named storm activity. One of the most common climate forcers used is El Niño Southern Oscillation (ENSO) and, this year, many forecasts are uncertain if an El Niño event will take hold during the summer, which historically suppresses hurricane activity. CSU thinks an El Niño will be weak or moderate by the peak of the Atlantic hurricane season based on their April forecast. However, as mentioned a few weeks ago, spring El Niño forecasts can be notoriously misleading, and result in difficult forecasts. (This phenomenon is so familiar that it has its own name – the “spring predictability barrier”.) Over the last few months many of the monthly climate models have backed off of the idea of a strong El Niño during the peak of the Atlantic hurricane season and now have a weak to neutral ENSO condition. If the El Niño is weak, it could result in increased landfall chances, and El Niño historically has little to do with any activity in the Western Caribbean / Gulf of Mexico and any activity in this region increases the chances of U.S. landfall.

Official Climate Prediction Center ENSO probability forecast for Mid-April (Top) and Early May (Bottom) Showing in just a half of month the probability of a El Niño during the hurricane season (Gray Box) went form 70% to below 50%. There is an increasing signal that ENSO will be neutral during the hurricane seasons.

The other challenge this year is that earlier this spring, water in the far North Atlantic and water off the coast of Africa had a relatively cold signal which is potentially indicative of a negative phase of the Atlantic Multi-Decadal Oscillation (AMO).  However, over the last month or so, the Atlantic water has warmed substantially.  This continues the debate as to whether the AMO has switched to a negative phase.  The U.S. government suggests the Atlantic is still in a positive state, whereas the CSU data suggests the AMO has trended negatively over the past few years.  If water continues to warm over the main development region, like it has over the last month, it could allow more storm formation in the heart of the hurricane season.

NOAA SST anomaly (degree C) for 4/10 (left) and 5/11 (right) showing a warming of SST off the west coast of Africa off the East Coast of the US. The cold SST in the North Atlantic have expanded and SST after months of above normal in the Gulf Of Mexico have recently turned colder than normal which should be short lived.

Another factor that has had a large influence on named storm activity over the last few years has been the Saharan Air Layer (SAL).  Named storms interact with the SAL in several ways.  Some named storms get embedded in the SAL their entire life-cycle and often struggle to intensify beyond strong tropical storm strength.  Other named storms can be overrun by the faster moving SAL and are quickly weakened.  The SAL in general can hamper convection, making it hard for named storms to develop.  This year could be similar to the last couple of years which would hamper development of named storm activity in the main development region but, as tropical waves get closer to the U.S. and Caribbean, the SAL decreases, and conditions become more favorable for development outside of the SAL.

SST anomaly for 5/11 showing warmer than normal SST around Hawaii.

Not to forget about Hawaii, which is also a target for named storm activity and, like the U.S. mainland, has gone a long time without a major hurricane impact.   This year, the insurance industry should also keep an eye on this 50th state as, just like the warm sea surface temperature (SST) off the East Coast of the U.S., the SSTs are above normal near Hawaii, and any tropical activity that might come close to the islands could be enhanced by these warmer than normal SSTs.

Summary
Forecasting of Atlantic named storm activity is not easy, and CSU has demonstrated variability in skill year over year, with no real improvement in the April seasonal forecasts over the last several years, but overall there is skill improvement over using basic climatology. Although some forecasts are currently calling for below normal activity in the Atlantic basin, climate forcers are pointing toward the ideas that these forecasts will be adjusted upward as we approach June 1 to a more active or normal season. The major climate forcers suggest there could be less development in the main development region of the Atlantic but, as tropical waves move closer to the U.S., they could have a better chance at developing, due to lack of wind shear and lower SAL environment. SSTs near the U.S. coastline are also expected to be warmer than normal which would add fuel to any disturbances that develop. Therefore, parts of the U.S. coastline have a higher probability of a landfalling named storm this season, with the Mid-Atlantic and Northeast seeing the highest chance.
Resources:
Barcelona Supercomputing Center has a nice summary of the various Atlantic Hurricane Forecasts
http://www.bsc.es/ESS/seasonalhurricanepredictions/
NOAA Climatology Products – Avg Start Dates, Return Periods, Develop Origin by Date, Strike Density
http://www.nhc.noaa.gov/climo/
CSU U.S. Landfalling Hurricane Probability Project
http://www.e-transit.org/hurricane/welcome.html

BMS Seasonal Outlook April 2017

Summary:

  • An El Niño is forecasted to emerge for late this summer, but weather patterns suggest that it has already arrived.
  • Late spring-early summer warming will occur over the central and eastern U.S.; then, temperatures will trend cooler into the summer for the northern plains.
  • Heavy spring rains across the Gulf States and into the Great Plains will accompany storm systems, but nothing like past record years (like 1993).
  • Best matching analog years: 1982, 1986, 2004, 2006 and 2014

The Pattern

There has been no shortage for the insurance industry of severe weather during the first quarter of 2017. A warmer-than-normal start to the year, aided by record Gulf of Mexico sea surface temperatures, has produced a relatively active period of severe weather. Will this weather pattern continue into the next few months, or are we on the road to a quieter-than-normal weather pattern?

Severe weather reports from Jan 1 – April 20, 2017. Bar graph shows the number of reports per day so far this year.

In reviewing the first three months of 2017, the weather patterns have been dominated by Pacific influences, with storm after storm pounding the West Coast. As these storm systems moved across the U.S. and into the central U.S., they were enhanced by tapping a large amount of warm air from the Gulf of Mexico, which also produced warmth across the eastern U.S. This weather pattern has provided plenty of opportunity for severe weather, and resulted in several significant severe weather outbreaks that impacted the insurance industry. Some of the bigger events occurred on January 2, 21-23, February 28-March 1, March 6-7, and most recently, April 2-3.

So far in April, it would appear this weather pattern has continued the pattern established in March, with a series of infrequent, but very energetic storm systems digging into the western U.S. before lifting up into the mid-west and northeastern U.S.  This has meant that much of the U.S. should continue to experience similar above-normal severe weather activity; but these storm systems should start traversing a more northern track across the northern-tier states.  This pattern indicates that June-like weather might appear in April and May.

Long-Range Forecasts

Many long-range climate forcer signals can provide seasonal forecasters clues about what weather to expect over the next few months.  The El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and Atlantic Multidecadal Oscillation (AMO) are some of the most common signals.  Although ENSO seems the most popular climate forcer in recent seasonal forecasts, a few words of caution are required:  fickle spring weather is notoriously misleading and results in difficult forecasts (this phenomenon is so familiar that it has its own name, the “spring predictability barrier”).   Second, we are technically coming out of a weak La Niña (which has a traditionally predictable outcome), but the atmosphere isn’t following its typical pattern following a weak La Niña.  Instead, the weather pattern over the continental U.S. reflected more of an El Niño pattern, with widespread warmth across much of the country and above-normal precipitation across parts of the southern tier and West Coast states.

The PDO has been positive for a record 39 months (during a positive phase, the west Pacific becomes cooler and part of the eastern ocean warms), but the weather pattern over the western U.S. has been anything but reflective of a positive PDO pattern.  Usually a positive PDO will lead to warmer and drier conditions in the western U.S., but this has not been the case over the last few months.

Weekly U.S. Drought Monitor, which uses a composite index on the level of drought that is occurring

Seasonal forecasting can also help us understand current areas of drought.  Large areas of moderate-to-severe drought can create a positive feedback loop, meaning that already-dry regions are more susceptible to warm and dry weather than non-drought areas.  As illustrated by the above map, patches of drought are currently scattered throughout the country, but these scattered patches are too insignificant to raise red flags for long-term warm and dry conditions over next few months.

Research suggests that the continued warm water temperatures in the Gulf of Mexico will likely mean severe weather will continue to erupt over the southern and central U.S. into late spring.  Historically, when the Gulf of Mexico trends warmer than normal, there is more energy to fuel severe storms and tornadoes.

Convective energy is needed for storm development and correlates to storm activity.

The Verdict

Evaluating recent weather patterns and various climate forcers produces the following analog years: 1982, 1986, 2004, 2006, and 2014.  These years suggest an active storm pattern that may result in:

  • Much of the U.S. experiencing near-normal temperatures between April-August
  • The western U.S. and southeast warmer then normal
  • The northern states slightly colder than normal

Combining the analog years yields the following temperature and precipitation anomalies. Note the temperature scale is less than a 1 degree +/- long term average.

However, above-normal national temperatures now and into early summer should give way to more normal temperatures or cooling temperature patterns in the Great Plains later in the year.  Hit-or-miss precipitation across much of the country will be a by-product of severe weather and will provide rain in some areas but not others.  As a result, dry conditions in the southeast could progress into summer.  Severe weather should remain active until May, with activity waning to more normal levels as summer progresses; but overall, the insurance industry should expect to see much higher levels of insured loss than in the last few years.

 

BMS Tropical Update 10/3/2016 11 AM CDT

Summary

  • Matthew continues to be a powerful category 4 hurricane 275 miles SW of Port Au Prince Haiti.
  • Matthew will be a devastating hurricane for Haiti and the Bahamas.
  • It should not be surprising if Matthew become a category 5 hurricane near Haiti and Cuba.  Little weakening should be expected from the higher topography as  Matthew  tracks between Haiti and Cuba.
  • NHC is still under-forecasting the overall intensity of Matthew north of the Bahamas and I don’t see any reason why it would not be a major hurricane north of the Bahamas.
  • Although Matthew is a small size hurricane at this time, hurricane force winds extend 30 miles from the center and tropical storm force winds extend 195 miles from center.  Matthew’s size should grow in extent north of the Bahamas, increasing wind related impacts.
  • Matthew’s forecast model guidance has shifted to the West closer to the U.S. overnight. This increases the probability of U.S landfall.  This even increases the threat of a Florida landfall or impacts.  But at this time over the next week the highest U.S. landfall probability is North Carolina and the Outer Banks.
  • Still an option on the table is that Matthew could stall off the Southeast coastline and not turn out to sea.  There are a lot of options on the table north of the Bahamas as the forecast has a large amount of uncertainty still.

Matthew Size and Strength to the North

Yesterday I pointed out how small Matthew was, but already today the size of hurricane force winds has doubled to over 30 miles from the center of the storm.   I expect the size of Matthew to get much larger as it tracks north particularly in the Bahamas and points North.

103matthewwindfeild

HWRF forecast for Sat Oct 8 showing a much larger windfield as Matthew moves northward.

I still feel the NHC is too weak on its intensity forecast North of the Bahamas.  Besides wind shear there is nothing preventing Matthew from becoming a major hurricane north of the Bahamas as the waters off the east coast are above normal temperature and can support a stronger hurricane.   This also means as the track of Matthew shifts closer to the U.S. expect a higher insured impact even from a bypassing storm.

U.S. Threat Increasing

Over the weekend the U.S landfall probability was fairly steady.  However, with the northward turn of Matthew and the huge amount of data now flowing into the global weather models from extra weather balloons and aircraft the models might be getting a better handle on the future track of Matthew.  In fact, over night the threat has increased for the U.S. and a U.S. landfalling hurricane is not off the table.  There is still a probability of this occurring even in Florida. The North Carolina Outer Banks have the highest probability of landfall at this time, but there can be high insured impact even if the storm bypasses the U.S coastline.  Remember Floyd in 1999 never made a Florida landfall, but caused 50 million in insured losses at the time.  In total as Floyd moved up the U.S coastline it’s insured impacts would be equivalent to a 4.5 billion dollar insured loss today.

floydat199906

1999 Hurricane Floyd track up the East Coast of the U.S.

The probability of a U.S landfall has increased from 35% to 45% probability as the overall guidance has shifted to the west toward the U.S. coastline with a 55%  likelihood Matthew will staying out to sea beyond the Bahamas.  However, as stated since last week, it is a complicated forecast with lots of options on the table.  The ridging in the central Atlantic seems to be increasing which is likely going to continue to force Matthew westward a bit. Some models even merge the newly designated Invest 98 which is currently a broad area of low pressure located about 400 miles northeast of the northern Leeward Islands.

103matthewinvest98l

 


As I talked about last Thursday, there was a chance Matthew might stall off the southeast coastline, this option is still on the table and last night’s ECMWF model shows this in the red line in the ECMWF ensemble forecast below.

103matthewecmwfens

ECMWF forecast in red. Shows Matthew stalling out. The NHC official forecast shown in black line. 51 individual ECMWF forecast shown in gray lines many with Florida landfall which cannot be ruled out.

BMS Tropical Update 10/2/2016 10 AM CDT

Summary

  • Matthew is still a powerful category 4 hurricane 340 miles southwest of  Port Au Prince, Haiti.
  • Matthew is a very small storm with hurricane force winds only extending out from the center 25 miles.
  • Matthew’s impact to Haiti will be devastating.  Flooding rains and a rare hit from the south will make this a unique event.
  • Forecast track guidance has been shifting eastward over the last 24 hrs
  • Florida landfall threat appears to be off the table with only a very small probability at this time.
  • Less weakening from higher topography is now forecasted as Matthew passes between Cuba and Haiti.
  • North of the Bahamas, Matthew is still expected to be a major hurricane.
  • Beyond the five day forecast, models are still playing the game of back and forth with the forecasted track north of the Bahamas.  There is no change in the landfall probabilities from yesterday which still stand at a 35% probability of US landfall during the course of Matthew’s trek north and a 65% likelihood of staying out to sea beyond the Bahamas.  It should be noted that the forecast is still complicated and any northeast landfall is still a week away.

Matthew  Impacts

Matthew has now finally turned North and is moving at a northwest direction at a slow speed 5 mph. Matthew’s smaller size storm might be one of the only positives of a major hurricane hitting Jamaica, Cuba and Haiti.  Currently Matthew’s eye is only 12 miles across and hurricane force winds only extend out from the center 25 miles.  Matthew will continue to grow in size as it moves northward, but its small size should keep overall wind damage at a minimum as the strongest winds (Right side of hurricane) hit Haiti.

102matthewsmallsize1

 

102matthewsmallsize2

The biggest impact to Jamaica, Cuba and Haiti will be flooding rains.  Up to 40” of rain is forecasted over Haiti which will be devastating for this poorly developed country.  Overall insurance penetration is low in Haiti and many areas are still recovering from the devastating 2010 earthquake.

102matthewrainfall

It should be noted this is rainfall from yesterday forecast. Today’s has not been posted yet, but I expect similar amounts

Over the last 24 hours the official NHC forecast track has been shifting eastward. This means less impact to Jamaica and more impact to Haiti.  This also decreases the overall probability of any Florida impacts to the insurance industry.

102matthewnhcguidance

Past 24 hours of NHC Official forecast tracks. The darker the color the more recent the forecast track.

The track northward in-between Haiti and Cuba will limit the impact of higher terrain.  This rare southern side impact will result in a rare impact for Haiti and will lead to issues of storm surge not usually seen on the southern bays and inlets.

102matthewraresoutherntrack

No Category 4 hurricane as come up from the south in this part of the Caribbean Sea.

Beyond 5 day Forecast

Forecast model guidance and very warm sea surface temperatures along the east coast of the U.S. will allow Matthew to maintain its major hurricane status north of the Bahamas and possibly north of North Carolina.

102matthewintensity

Most model guidance maintain a major hurricane for the entire forecast period.

Beyond the five day forecast, models are still playing the game of back and forth with the forecast track north of the Bahamas.  There is no change in the landfall probabilities from yesterday which still stand at a 35% probability of US landfall during the course of Matthew’s trek north and a 65% likelihood of staying out to sea beyond the Bahamas.  It should be noted that the forecast is still complicated and any northeast landfall is still a week away.  Below is a look at the WSI calibrated hurricane risk products from the GFS and ECMWF models suggesting a 50% chance Matthew will make U.S landfall.  My probability is lower at this time which is more inline with the current NHC official forecast.

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GFS hurricane risk.  Over 60% chance U.S. will see hurricane landfall.

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ECMWF forecast suggesting U.S has a 50% chance of hurricane landfall.

BMS Tropical Update 9/29/2016 11 AM CDT

As of 11 am EDT the  NHC suggests Tropical Storm Matthew is close to a hurricane with a location 290 miles south of San Juan Puerto Rico.   With any of the next advisories the named storm could be upgraded to a hurricane.

Forecasted Intensity

As highlighted over the last two tropical updates Matthew will be moving over warm water and it will be this warmer than normal water that will provide the fuel for Matthew to strengthen into a major hurricane by Monday.   Over the next few days as Matthew moves westward wind shear will limit rapid strengthening of the system.

After Matthew starts its turn northward it should rapidly strengthen and will likely be a category 3 hurricane near the Eastern shores of Jamaica or Haiti.  In the longer range forecast for later next week one could expect some slight weakening of the system as it interacts with higher terrain from the mountains of Cuba and Haiti.

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Forecasted Track

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Now is a good time to remember what the National Hurricane Center cone of uncertainty means.   A layer that is within BMS iVision it does not reflect real-time uncertainty within the forecast of Matthew. The width of this uncertainty is solely determined by historical errors of past hurricane tracks and not the current uncertainty with track spread within Matthew.

The NHC lists five important points to help users understand the cone.

  • The cone represents the probable track of the center of the tropical cyclone.
  • The size of the cone is drawn so that about two-thirds of the time, the center of the storm will remain in the cone.
  • The cone does not take the size of the storm into account.
  • A hurricane is not a point; impacts often occur well outside of the core.
  • The cone indicates the forecast up to five days out from the last recorded position of the storm.

Overall I like the ideas the NHC has forecasted for the next 5 days.  I think the NHC may slightly shift the track closer to Jamaica over the next few days, but in general the forecast model guidance suggests that Matthew should be either near Jamaica or Haiti by Monday and most of these forecasts have Matthew as a major hurricane at this time.   After this there still is a great amount of uncertainty in the long range forecast from days 5 – 10.

The key will be how Matthew interacts and turns with the upper level trough of low pressure.

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There is some indication that Matthew could stall out near the Bahamas early next week, maybe similar to what happen to hurricane Joaquin last year.  However, below is a look at just how much uncertainty there is with the 10 day forecast from the ECMWF ensemble showing the low pressure centers from the latest model run.

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Right now the Gulf Coast states look to be in the clear, but Florida and points along the East Coast need to pay attention to this  complex forecast situation in the long term.

GFS Ensemble Long Range forecast tracks for Matthew

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ECMWF Ensemble Long Range Forecast Tracks for Matthew

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Since 1900 the only major hurricane to make landfall after today north of Florida along the U.S. East Coast was Hazel in 1954 near the NC/SC Border and in some regards Matthew has some similarities in the long range forecast.

BMS Tropical Update 9/28/2016 12 PM CDT

As I wrote about this past weekend, Tropical Storm Matthew would likely form over the southern Caribbean islands and there was uncertainty in the long range forecast of where Matthew might end up in the long range.   Well, sure enough this morning Matthew formed just east of the Caribbean as a strong 60 mph tropical storm. Forecast models continue to suggest this storm will intensify over the next several days.  Unfortunately no one knows where Matthew will make landfall at this point and it is far too soon to provide specifics to what will occur later next week.

What we do know

In general we know Matthew will continue to move westward across the southern Caribbean Sea for the next several days.  As Matthew moves westward it will move over very warm water and as I pointed out on Sunday this water is much above normal temperature.

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928matthewheatcontent Above is the current Sea Surface Temperatures and Tropical Cyclone Heat Potential both of which can support a major hurricane.

We know if wind shear decreases it will allow for rapid strengthening of  Matthew over this very warm water so in general the likelihood of a major hurricane (Category 3 with winds 111 mph or greater) is likely to happen by this weekend.

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Current Forecast intensity model guidance for Matthew. There is little doubt Matthew will be a hurricane soon and likely a major hurricane later this weekend

We know that the short term forecast of Matthew will allow for a storm’s track of a westward motion over the next four to five days. We also know for the last several days the forecast models have been consistent in suggesting the storm will turn north in the central Caribbean.  This means insurance companies from along the Gulf and East coasts should be aware that there is the potential for a hurricane landfall sometime in the middle of next week.

What we don’t know

What we don’t know is the overall end game for Matthew at this time which should unfold later next week.  This is because the timing of the northward turn is still unclear.  The American Global Forecast System (GFS) weather models suggest the storm will begin to turn on Saturday in the central Caribbean, hitting Haiti on Sunday and then miss Florida but then could impact parts of the East Coast late next week. The European (ECMWF) model is forecasting the sharp turn later on Monday next week therefore allowing for a farther westward track into the Caribbean. In that scenario, it would hit Cuba on Tuesday and have a good chance of impacting Florida or moving into the Gulf of Mexico.   These are the two best long range weather models available and they offer different outcomes on what could occur next week.  As I have pointed out before there is no certainty in a long range forecast, but general ideas can start to take shape so at this time don’t follow just one forecast, look at all the possible solutions.  However, if I were to place a bet on which model might be right next week I would choose the ECMWF model.

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This is the GFS Ensemble Model Solutions suggesting a earlier turn to the North.

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This is the ECMWF ensemble model solutions suggesting a more westward track.

Historically, tropical storms in October tend to turn north sharply after they reach the Caribbean. Looking back at a few storms that made a sharp turn to the north, like this storm is expected to do, one of the most recent would be Wilma which was the last major hurricane to hit the U.S. 3993 days go. Wilma made a very sharp turn northward near Mexico’s Yucatan Peninsula before hitting Florida.  Another noteworthy storm was  Hurricane Hazel in 1954 which looks very similar to what the models are forecasting for this week’s storm. Hazel formed just before reaching the Caribbean, turned abruptly to the north and passed between Hispaniola and Cuba impacting the east coast of the U.S.

BMS Tropical Update 9/14/2016 12 PM CDT

I think everyone was surprised to the naming of  Tropical Storm (TS) Julia overland last night at 10 PM EDT. My jaw basically dropped when my iPhone alerted me that the National Hurricane Center (NHC) upgraded investigation area 93L to named storm Julia.
This was a huge surprise for many other meteorologists as well and likely even caught the NHC off guard: Just nine hours earlier they had only given the system 40% chance (image below) and 12 hours prior only a 20% chance of development over the next 48 hours. In fact, the NHC didn’t even classify the system as a depression – the system went straight to a named storm. So clearly, the system developed rapidly by feeding off the very warm waters off the Florida coast.

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A look at yesterday 2 pm EDT NHC 5 Day probability of tropical cyclone formation. At 11 PM EDT they upgraded the storm to Tropical Storm Julia

The other surprising fact is that Julia was overland most of yesterday, and it’s really rare for a storm to be named overland. In fact, The Weather Channel’s Michael Lowry reported that only 2% of all tropical cyclones in the Atlantic have formed over land. But according to Philip Klotzbach at Colorado State University, none of the 2% actually formed over Florida, and Julia will go into the record books as being the first named storm to form over Florida and not make landfall.

The other interesting fact is that the NHC barely acknowledged the overland tropical system that will likely have an economic impact above $10 Billons in Louisiana. So the NHC seems to be making up for this mistake by forecasting that Julia will likely also have large flooding impact across the Southeast U.S. and it should have a name like the Louisiana system should have had a name.  It’s possible, but I have been clear that the NHC plays name games with systems, and the storm name (or lack thereof) is less important than the storm impact.

TS Julia will remain overland, quickly weaken today to a Tropical Depression, and park itself over Southern Georgia where it will cause flooding rain (which is likely to be the main insurance impact).

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Tropical Storm Julia Rainfall Forecast showing 2 – 8″ of rain over the next 72 hours over the southeast coast of the U.S.

Tropical Depression 12 just formed near Cape Verde and will struggle to move generally west over the next several days. At this time, is not a threat to the insurance industry. Named storm Karl should be expected later today.

Peak Season

September 10 marked the statistical peak of the Atlantic hurricane season. Based on data gathered since 1851, it’s more likely for a named storm to be active on this date than on any other date in the entire season — from June 1 to November 30. However, this year brought no named storm on September 10. This absence has only occurred in 12 of the past 50 years.
Although Julia’s progression highlights issues with the inconsistency of naming named storm, this year’s count is above normal so far this year. The average date for 11th Atlantic named storm is Nov. 23 and Karl is expected to be named later today. In terms of Accumulated Cyclone Energy (ACE), the basin as a whole is 75% below normal with Hurricane Gaston generating more than 59% of the total ACE this season.

aceasof9_14_2016

As I predicted at the start of the season, storms have struggled to develop in the Main Development Region (MDR) of in the Atlantic Ocean and have developed closer to the U.S. This is due to the large amount of dry dusty air in the atmosphere in this area of the Atlantic basin. This should result in storm having a better chance to form closer to the U.S.

For the Remainder of the Season

The insurance industry should expect more of the same. With warm water, less shear and dry air near the U.S. coastline, conditions are ripe for storm development. The ECMWF ensemble % chance of tropical cyclone development guidance might be the best way to sum up the current and future activity of tropical cyclone activity over the Atlantic Basin over the next two weeks.  As overall I expect less activity over the basin next week as an large scale area of sinking air moves over much of the basin next week.  As of right now besides Julia I don’t expect any U.S. insurance industry concerns over the next two weeks.

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