[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT44 KNHC 161440
TCDAT4

Hurricane Sally Discussion Number  22
NWS National Hurricane Center Miami FL       AL192020
1000 AM CDT Wed Sep 16 2020

NWS Doppler Radar and fixes from an Air Force Reserve Hurricane
Hunter aircraft indicate that Sally made landfall near Gulf Shores,
Alabama, around 0945 UTC with an intensity of 90 kt and a minimum
central pressure of 965 mb.  Since that time, the center has been
inching its way inland over southeastern Alabama and the extreme
western portion of the Florida panhandle.  The eye has degraded in
radar imagery, and Doppler velocities are gradually decreasing.
The intensity has therefore been reduced to 70 kt for this
advisory.  Sally should continue to rapidly weaken today, and once
the majority of the circulation is onshore by Thursday morning, it
should weaken to a tropical depression.  The remnant low is forecast
to be absorbed by a frontal boundary near the southeastern United
States coastline in a couple of days.

Radar and the earlier aircraft fixes show that the longer-term
motion is 030/4 kt. Sally should continue to move north-
northeastward to northeastward with a gradual increase in forward
speed as it enters the southern extent of the mid-latitude
westerlies over the next 24-36 hours. A faster east-northeastward
motion is expected by 36-48 hours before Sally or its remnants
merge with the aforementioned frontal zone.  The updated NHC track
forecast is close to the HFIP corrected consensus, which is
slightly north of the previous advisory.

As Sally moves inland, ongoing heavy rainfall and flooding will
spread northeastward across southeastern Alabama and portions of
Georgia and western South Carolina during the next day or two.

KEY MESSAGES:

1. Historic and catastrophic flooding, including widespread moderate
to major river flooding, is unfolding along and just inland from
west of Tallahassee, Florida, to Mobile Bay, Alabama. Significant
and widespread flooding is likely across inland portions of Alabama
into central Georgia, and possible across western South Carolina,
western and central North Carolina, and far southeast Virginia.

2. Life-threatening storm surge is occurring along portions of the
coastline from Alabama to the western Florida Panhandle, including
Pensacola Bay.

3. Hurricane conditions are expected to continue this afternoon
within portions of the Hurricane Warning area in southern Alabama
and the western Florida panhandle.

FORECAST POSITIONS AND MAX WINDS

INIT  16/1500Z 30.6N  87.4W   70 KT  80 MPH...INLAND
 12H  17/0000Z 31.3N  86.7W   45 KT  50 MPH...INLAND
 24H  17/1200Z 32.4N  85.4W   30 KT  35 MPH...INLAND
 36H  18/0000Z 33.6N  83.1W   25 KT  30 MPH...INLAND
 48H  18/1200Z 34.6N  80.2W   25 KT  30 MPH...POST-TROP/REMNT LOW
 60H  19/0000Z...DISSIPATED

$$
Forecaster Brown
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