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Tropical Storm Laura Discussion Number  13
NWS National Hurricane Center Miami FL       AL132020
1100 PM AST Sat Aug 22 2020
 
Laura is now located near the eastern portion of the Dominican
Republic, and it is producing a large area of showers and
thunderstorms over much of Hispaniola and adjacent areas.  The NOAA
Hurricane Hunters have been flying in the tropical storm this
evening and have found winds to support maintaining the initial
intensity of 45 kt. Dropsonde data from the aircraft suggests that
the pressure has fallen a little to 1003 mb, and that the center is
still quite elongated.
 
Laura is moving west-northwestward at 14 kt.  The track forecast
reasoning is generally unchanged from earlier. A subtropical high
pressure system is expected to build westward during the next few
days, which should continue to steer Laura generally
west-northwestward at a fairly quick pace.  This track should take
the storm across Hispaniola tonight and early Sunday and then across
Cuba late Sunday and Monday.  Laura is then expected to emerge over
the eastern Gulf of Mexico, where it will likely turn northwestward
and slow down some as it reaches the western side of the ridge.  The
models are in fair agreement that Laura will generally follow a
similar path to Marco when it nears the northern Gulf coast in 3 to
4 days.  There has been little change in the guidance this cycle,
and the NHC track forecast is largely an update of the previous one.
This forecast is near the typically reliable TVCA and HCCA
consensus aids.
 
Since the tropical storm is expected to track across the
mountainous islands of Hispaniola and Cuba during the next 36
to 48 hours, little change in intensity seems like a good bet during
that time period.  However, after the storm pulls away from the
islands and moves over the warm Gulf of Mexico waters while being
in low wind shear and high moisture conditions, strengthening seems
very likely. Most of the better-performing intensity models show
Laura making landfall along the U.S. northern Gulf coast as a
hurricane in about 4 days.  The NHC intensity forecast is slightly
higher than the previous one, and it lies roughly near the middle
of the guidance suite.
 
Key Messages:
 
1. Tropical storm conditions are expected to continue across
portions of the U.S. Virgin Islands and Puerto Rico for a few more
hours. Tropical storm conditions are also expected across portions
of the Dominican Republic and Haiti, the Turks and Caicos, the
southeastern Bahamas, and central and eastern Cuba through Sunday.
Heavy rainfall is likely across these areas and could cause
mudslides and flash and urban flooding through Sunday, with
widespread river flooding possible in Puerto Rico.
 
2. Tropical storm conditions are possible over portions of
central and western Cuba, the central Bahamas and Andros Island
Sunday night and Monday, and in the Florida Keys on Monday.
 
3. The details of the long-range track and intensity forecasts 
remain uncertain since Laura is forecast to move near or over 
portions of the Greater Antilles through Monday. However, Laura is 
forecast to strengthen over the Gulf of Mexico and could bring storm 
surge, rainfall, and wind impacts to portions of the U.S. Gulf Coast 
by the middle of next week. This could result in a prolonged period 
of hazardous weather for areas that are likely to be affected by 
Tropical Storm Marco earlier in the week. Interests there should 
monitor the progress of Laura and Marco and updates to the forecast 
during the next few days.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  23/0300Z 18.3N  69.6W   45 KT  50 MPH
 12H  23/1200Z 19.3N  72.3W   45 KT  50 MPH...INLAND
 24H  24/0000Z 20.6N  76.0W   45 KT  50 MPH...INLAND
 36H  24/1200Z 22.1N  79.6W   45 KT  50 MPH...INLAND
 48H  25/0000Z 23.4N  83.0W   50 KT  60 MPH...OVER WATER
 60H  25/1200Z 24.7N  85.8W   60 KT  70 MPH
 72H  26/0000Z 26.2N  88.0W   75 KT  85 MPH
 96H  27/0000Z 29.8N  91.2W   80 KT  90 MPH...INLAND
120H  28/0000Z 34.7N  89.6W   30 KT  35 MPH...INLAND
 
$$
Forecaster Cangialosi
 
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