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Hurricane Laura Discussion Number  31
NWS National Hurricane Center Miami FL       AL132020
1000 AM CDT Thu Aug 27 2020
 
Laura has continued to move inland over west-central Louisiana this
morning.  Satellite and radar imagery has shown a gradual filling of
the eye, and a reduction in Doppler velocities in the northeastern
eyewall. The initial intensity is set at 65 kt, based on a reduction
of the Doppler velocities and the typical filling rate of inland
hurricanes.  The highest wind gusts at official observing sites
within the past few hours has been at Alexandria, Louisiana, where a
gust to 75 kt has been reported.
 
The hurricane is moving slightly east of due north or 005/14 kt. A
general northward motion should continue through this evening as the
hurricane moves around the western portion of a mid-level ridge over
the southeastern United States.  Laura should turn northeastward
overnight while it moves across Arkansas and becomes embedded within
the mid-latitude westerlies.  A faster east-northeastward motion is
forecast by late Friday, which will bring Laura or its remnants
across the central Appalachians and to the Mid-Atlantic states on
Saturday. After that time, the system is expected to accelerate
east-northeastward to northeastward over the western Atlantic.
 
Laura will continue to rapidly weaken today while it moves farther
inland.  The cyclone will become a tropical storm this afternoon and
is expected to weaken to a tropical depression tonight or early
Friday.  Although Laura is weakening, strong wind gusts are likely
to spread over northern Louisiana and Arkansas into this evening.
The UKMET and ECMWF models continue show the extratropical remnants
of Laura strengthening somewhat over the western Atlantic, and the
NHC forecast continues to depict the system as a gale-force low at
days 3-5.  An alternate scenario is for the system to be absorbed
by a frontal boundary over the western Atlantic before the end of
the forecast period.  The extratropical portion of the forecast is
based on guidance from the NOAA Ocean Prediction Center.
 
Key Messages:
 
1.  Dangerous storm surge will result in elevated water levels for
the next few hours along the Gulf Coast from Sabine Pass, Texas, to
Port Fourchon, Louisiana. In some areas where surge penetrated far
inland, flood waters will not fully recede for several days.
 
2. Damaging winds will continue near the center of Laura over
portions of northern Louisiana and Arkansas today and this evening.
 
3. Widespread flash flooding along small streams, urban areas, and
roadways will continue across portions of Louisiana, Mississippi,
and Arkansas.  Additional rainfall will also lead to minor to
moderate freshwater river flooding.  The heavy rainfall threat and
flash and urban flooding potential will spread northeastward into
the middle-Mississippi, lower Ohio and Tennessee Valleys, and
Mid-Atlantic States Friday and Saturday.
 
 
FORECAST POSITIONS AND MAX WINDS
 
INIT  27/1500Z 31.9N  93.1W   65 KT  75 MPH
 12H  28/0000Z 33.9N  92.7W   40 KT  45 MPH...INLAND
 24H  28/1200Z 35.8N  91.2W   30 KT  35 MPH...INLAND
 36H  29/0000Z 37.0N  87.7W   25 KT  30 MPH...INLAND
 48H  29/1200Z 38.0N  82.1W   25 KT  30 MPH...POST-TROP/INLAND
 60H  30/0000Z 38.7N  74.9W   30 KT  35 MPH...POST-TROP/INLAND
 72H  30/1200Z 41.8N  66.7W   45 KT  50 MPH...POST-TROP/EXTRATROP
 96H  31/1200Z 50.0N  53.5W   45 KT  50 MPH...POST-TROP/EXTRATROP
120H  01/1200Z 53.5N  43.0W   45 KT  50 MPH...POST-TROP/EXTRATROP
 
$$
Forecaster Brown
 
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