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BMS Tropical Update 10/3/2016 11 AM CDT


  • 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.


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.


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.



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.


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


  • 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.




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.


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.


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.


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.


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.


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


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

BMS Tropical Update 10/1/2016 11 AM CDT


  • Matthew is very powerful category 4 hurricane 390 miles southeast of Kingston, Jamaica and the second major hurricane of the 2016 Atlantic hurricane season.
  • No one – I mean NO one forecasted Matthew to rapidly intensifying into a category 5 Hurricane yesterday. This just goes to show how much work still needs to be done in the science of tropical cyclone forecasting especially for intensity.
  • Matthew has ended a 9-yr drought between category 5 hurricanes. The last category 5 hurricane in the Atlantic was Hurricane Felix.   It should be noted that this was the longest period in-between Atlantic Category 5 hurricanes since the period between the 1938 New England hurricane to 1953 hurricane Carol.  Another interesting fact is that Matthew was at category 5 about 30 miles from where Felix was a category 5.
  • Matthew should level off in terms of intensity, but a strong major hurricane is still expected as Matthew turns northward.
  • Beyond the five days forecast, models are trending east or west with every other run. Its a bit of back and fourth at this point.  However, I can finally provide a few ideas on landfall scenarios. There is currently 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.

Next Few Days

As predicted all week today is the day that Matthew should start to take a right turn and move into the central Caribbean.  This will then help determine where and when Matthew  tracks along the eastern U.S. seaboard. While many details remain unresolved in regards to Matthew’s future track, there are still indications that Matthew could impact the northeastern states at significant amplitude sometime between October 10-12. The purpose of this blog is not to HYPE but rather show an objective model analysis to illustrate risk and give all scenarios that are on the table at this time.

The National Hurricane Center is still showing Matthew make a right turn and track over the weekend as a Category 3 major hurricane, which increases the risk for significant impacts across areas including Jamaica, Cuba, and Haiti from the south which is a bit rare direction for a hit for these islands This could increase wind loss given most building / trees have not seen this unique wind direction. Storm surge could also be an issue in some of the southern bays which usually don’t see a storm from this direction.

Matthew will likely weaken as it crosses Cuba, Jamaica, Haiti, where intensities should drop to a Category 2 hurricane. After this one might notice that the latest NHC forecast now expect Matthew to be a major hurricane in the Bahamas.

There is no reason why Matthew should not  be a major hurricane as it track northward north of the Bahamas as it feeds off the above normal sea surface temperatures here.

East Coast Scenarios

Florida landfall is still on the table but at a lower probability at this time. However, this would be a decent insurance industry loss event as category 2 maybe category 3 impacts.

Matthew impacts Bahamas as a major hurricane and with a northward movement that could allow for an initial landfall across North Carolina’s Outer Banks sometime late next week or weekend (looking like Saturday, October 8) as a category 3 or 4 major hurricane, though the storm could also stay just offshore.  From there models show a northward track toward the northeastern states.

The most likely scenario at this time is the “Out to Sea” and no impact to the East Coast of the U.S.. Of course this would be the best scenario for insurance company.

Worst Case Scenario

Last night run of the American GFS model surely takes home the award for the worst case scenario so far of all the model runs I have seen.    (Again not HYPE and just one model solution of many and this one scenario is highly unlikely at this time)

The select sequence of this model runs below would rival the immortal hurricane Donna of 1960. In this scenario Matthew would do the unbelievable and allow hurricane force winds in every state from Florida to New England as Matthew tracks just off shore.


Florida Hurricane Force Wind From GFS 00z Model Run




Georgia Hurricane Force Wind From GFS 00z Model Run – Friday Oct 7th




South Carolina Hurricane Force Wind From GFS 00z Model Run – Sat Oct 8th



North Carolina Hurricane Force Wind From GFS 00z Model Run – Sat Oct 8th



New Jersey Hurricane Force Wind From GFS 00z Model Run – Sat Oct 8th



New England Hurricane Force Wind From GFS 00z Model Run – Sat Oct 9th

Again this scenario is one of many and highly unlikely.  The ECMWF ensembles model is more off shore today but overall the forecast is complicated next week. The newest 06z GFS ensembles are east of the worst case scenario shown above.


Above is the latest ECMWF model track guidance from the ensemble forecast


Above is the latest GFS model track guidance from the ensemble forecast

It should also be noted that the ECMWF has been performing better than the GFS thus far with Matthew.

Current Probability

Based on the current model guidance there is currently 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 to keep this short I have not explained why this is still complicated forecast. There are a lot of moving parts and more will be known today once Matthew takes that turn north and we get an ideas of the forward speed north.


BMS Tropical Update 9/30/2016 11 AM CDT


  • Tropical Storm Matthew is very close to becoming a major hurricane as it is 495 mile southeast of Kingston, Jamaica.
  • Matthew has intensified over the last 24 hr.    This was not forecasted to occur given the storm is still undergoing 20 kts of southerly wind shear.   Matthew is defying the odds and feeding off the warm Caribbean Sea waters we have talked about.
  • We have seen the NHC shift their track westward closer to Jamaica and they now have Matthew as it hits Jamaica.
  • The NHC still does not have Matthew as a major hurricane impacting the Bahamas.  I think they will change this guidance upward with a major hurricane in the Bahamas middle of next week.
  • The NHC cone of uncertainty is now closer to Florida so a Florida landfalling hurricane cannot be ruled out in the middle of next week.

What has changed in last 24 hrs

Matthew has intensified steadily over the last 24 hours and is very close to becoming a major hurricane. This is a bit of a chance in forecast as this increased intensity was not supposed to happen until it turned northward.  The idea that Matthew will be a major hurricane as it turns north toward Jamaica and Haiti is now in the NHC forecast guidance and along the thinking of yesterday BMS tropical update.   Matthew could still weaken due to interaction of the high mountains of Jamaica and Cuba on its way northward on Tuesday next week.  However, Matthew should rapidly regain its strength as a major hurricane over the Bahamas on Wednesday and Thursday next week.

Over the last several days we have seen the NHC track guidance shift westward.  It would appear this shift westward in track will now start to be consistent with a major hurricane hitting Jamaica.   What makes this interesting is very few major hurricanes in history have hit Jamaica from a southern direction so this could increase the insured loss on the island given an unusual wind direction for a major hurricane.


The NHC forecast brings Matthew near Jamaica as a major hurricane. Here’s the tropical systems to pass/hit Jamaica at Major Hurricane intensity. Interestingly, almost all of these tracks are more east-to-west vs. the expected south-to-north path that Matthew looks to take.

The ideas of Matthew weakening slightly due to the higher terrain of Jamaica, Cuba and Haiti is still on the table but I expect Matthew to rapidly strengthen again as it moves over the Bahamas on Wednesday next week.

Long Range Track Guidance Uncertainty

There are many possibilities that remain in play and there is not enough information to make a skillful assessment of ultimate outcomes at this time.  Possibilities are wide ranging from a track into southern Florida, an East Coast US landfall or even potentially out to sea into the Atlantic.  Over the past 24 hours there is some shift away from the Gulf of Mexico scenario and more towards a Florida US landfall or out to the Atlantic.


In terms of specific impacts north of the Caribbean, it’s too early to speculate on ultimate outcomes with Matthew until more information is available to make a skillful forecast.

In general the forecast models have still been shifting westward and the NHC has the edge of “cone” now grazing South Florida.

As we go into the weekend my general thoughts of Matthew impacting points along the Northeast coast later next week have to do with what the forward speed of Matthew might be once it starts it turn northward.  This will need to be watched very carefully.   The faster it comes north the better the chance it can reach the North Carolina coast before turning out to sea. If Matthew is slower coming out of the Caribbean it would likely have a better chance to be turned out to sea.  Also in the long range the option of turning out to sea is greater given the upper level pattern in the image I have provided below you will see the ridge (orange red colors)  is in a southwest – northeast direction as opposed to a northwest southeast direction which leave an option for Matthew with a way out to sea vs turning back into the northeast similar to Hazel and Sandy which had a different ridge configuration.


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.



Forecasted Track



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.

929matthew_turn1 929matthew_turn2

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.


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


ECMWF Ensemble Long Range Forecast Tracks for Matthew


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.


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.


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.


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


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 9/25/2016 11 AM CDT

At the start of the 2017 hurricane season you might remember the general prediction  was tropical systems will struggle over the main development region due to dry air and at times high wind shear.  However, as tropical systems take shape and move westward towards the Caribbean or U.S. coastline, the overall environment will become better for storms to strengthen.  So far this has been the case this season.

New Invest 97L

With little activity in the Atlantic Basin as Tropical Storm Karl swiftly moved across the North Atlantic the media is starting to hype the next tropical system.  This system has been tagged by the National Hurricane Center (NHC) as Invest 97L.

Currently Invest 97L is struggling with dry air and higher wind shear, but the system is starting out at a fairly low latitude, south of 10 degrees which generally means the system will track further west vs slowly curve to the north as it tracks westward across the Atlantic Ocean.  Steered by the subtropical ridge of high pressure known as the Bermuda-Azores high, Invest 97L will arrive in the Windward Islands on Wednesday bringing locally heavy rain and gusty winds. Such locations as St. Vincent and the Grenadines, Grenada, perhaps Trinidad and Tobago could be targeted islands.

You might have noticed that the (NHC) has given this system a high chance (80%) for formation into a tropical depression over the next 5 days. And many global models are suggesting a hurricane to develop after the system crosses the Windward Islands. The next named storm will be named Matthew.


There are currently west to northwest winds aloft over the Caribbean Sea, providing some wind shear which is typically hostile to the development and intensification of tropical cyclones. But if this wind shear diminishes there are very warm waters in the Caribbean which could add to the fuel of a developing tropical system.


However, as I always try to point out, the uncertainty is high and there is virtually no skill in long range hurricane forecasts seven to ten days for invest systems like Invest 97L.  There will be doom and gloom forecasts by weather models at these long range.  In some cases the model run might be correct but at this point in time it’s much too early to tell what the impacts will be after the Windward Islands.  Right now most modeling is trending away from U.S. impact and more to Mexico impact.


Climatology would suggest named storms entering the Caribbean during the period 9/20 – 10/10 at low latitudes such as Invest 97L often become major hurricanes, but if it makes a difference there have been 17 “M” named storms since 1950 and none have made U.S. landfall as a hurricane.

If the forecast changes and a U.S threat starts to take shape I will send more updates, but if anyone wants an update just ask.

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.


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).


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.


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.


BMS Tropical Update 9/3/2016 9 AM CDT

Hermine is about ready to write chapter four.  Chapter 1 – Unwillingness to develop across Atlantic.  Chapter 2 – Tropical depression in Gulf.  Chapter 3 – Southeastern landfall impacts ending the 10 year Florida hurricane drought.    Now chapter 4 is starting, which should be Northeast impacts.   Like many storms of the past, as storms exit back over the warm waters of the Gulf Stream and the frictional effects of land lessen, storms can easily intensify and over the next 24 hours this is what is expected with Hermine.

Gif Created on Make A GifHowever, it should be noted that this next chapter will not be similar to Hurricane Sandy.   I have seen a few reports that Hermine will be the next Superstorm Sandy, AKA Superstorm Hermine.   This is just a function of the 24/7 weather information era, social media hypecasters, and click bait that is all to common.   Each storm is different and it is easy to lock onto analog storms. I am guilty of doing that often.

However, Hermine is not Sandy, where are many differences between the two storms:

The setup is obviously different .  Sandy came up from the Bahamas and Hermine from the Gulf of Mexico so two totally different directions.

Sandy was a 940 mb low pressure system moving towards the New Jersey coastline with tropical storm force winds 1000 miles across and over 90 mph along the New Jersey coastline.   Hermine will have a low pressure center around 990 mb which is much higher and the tropical storm force winds will only extend out, less than 350 miles according to the latest National Hurricane center forecast.  However, both will likely be hurricanes off the New Jersey shore, but again this depends on how textbook the National Hurricane center is with the classification.


Sandy 850 mb winds and mean sea level pressure on the Left.  Hermine 850 mb winds and mean sea level pressure on right.

Sandy’s wave heights were historic at 30ft+   Hermine’s waves are only expected to be 20ft with maybe a few reports of 30ft.


Sandy Wave Height Left and Hermine Wave Height Right.


What will make Hermine impactful is this looks like this will be a long duration event. This means waves and wind will batter the northeast coastline for days, not hours like Sandy did.   There is still some track uncertainty and clearly the closer Hermine tracks to the coastline the worse the winds will be.  One can expect, given the long duration of strong winds, minor structural damage could occur.

Currently the Verisk Climate wind model which can be viewed in BMS iVision suggest these tropical storm force winds > 39 mph will not be impacting the New Jersey coastline, but this could change with the next few model runs.


This will also create coastal flooding problems with some area seeing close to record flooding which will be similar to Sandy along parts of the New Jersey coastline.

Instead of posting various flood forecast along the shore please go to the following site for the latest surge and flood information as these forecasts will change daily. 

At this time I don’t think the new National Hurricane Center storm surge inundation maps are capturing the full impact of the coastal flooding. 

BMS Tropical Update 9/2/2016 12 PM CDT

Hermine made landfall near St. Marks, Florida, around 1:30 am EDT with winds of 80 mph, making it a strong category 1 hurricane at landfall. As predicted, flooding rains, storm surge and tree fall have been the biggest insured impacts and overall should result in a minimal loss for the insurance industry. The storm has now weakened to a tropical storm near Savannah, Georgia. However, as mentioned in previous posts, Hermine will continue to track overland for the next 24 hours and exit the U.S. coastline near the outer banks of North Carolina. Unfortunately however, as we have seen over the last 16 days, the overall energy of this system is persistent. It now appears that Hermine won’t go away any time soon. After Hermine exits the East Coast, it will become a “post tropical” storm. This means that the storm will actually grow in size, and given that the water is as warm as it can possibly get off the East Coast of the U.S., it will continue to fuel Hermine’s circulation.

Below is a look at the warm sea surface temperatures off the East Coast.


Rule of thumb: 26C can maintain a tropical system. 28C can easily intensify it.

After Hermine moves off the East Coast, it will likely merge with a large-scale mid-latitude trough which will slow Hermine’s overall movement. Therefore, all but a few of the forecast models suggest that Hermine will stall over a 3-to-4-day period.


ECMWF ensembles: Most members “Stall” Hermine, some members hook inland, others out to sea. Still some uncertainty watch closely.


Where Hermine takes turn to North and stalls will be an important factor for Mid-Atlantic impacts. The farther east, the better


This is bad new for the barrier islands and beach communities along the Mid Atlantic. Historically high amounts beach erosion will occur with a very constant wind direction for several days. Keep in mind that this constant flow of water will continue to push water into the back bays, and this water will have no outlet. This will result in major coastal flooding, and perhaps even record flooding, along the New Jersey coastline.  The latest extra-tropical storm surge map forecast can be be found here:


Major to record flooding forecast Sunday night for many stations along NJ coastline. Record at Cape May is 9.0 feet from January Nor’easter. These forecasts will change several times a day and will depend on the track of Hermine.


The winds over this 3-to-4-day period will be very similar to a strong nor’easter, and regardless of how the system is classified and where it might wobbles off the East Coast, tropical storm force winds could blow in many areas of the coastline. There is even a chance that Hermine could regain hurricane status. I have already made my point this week that the NHC seems to be treating the hurricane classification as a classroom lecture. Right now, the storm’s classification is far less important than its ultimate impacts.

There are very few storms of this size that have stalled off the East Coast. One of those storms was the Ash Wednesday Storm (1962) and Hurricane Esther (1961), both of which produced significant insured impacts along the East Coast.



Hurricane Esther was the first large tropical cyclone to be discovered by satellite imagery.

Great video talking about the storm of 1962 and the lessons that have been learned and why one might not see the same type of damage today.