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.