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Tropical Storm Beta Discussion Number 19
NWS National Hurricane Center Miami FL AL222020
400 AM CDT Tue Sep 22 2020
Beta's center has continued to move farther inland since making
landfall on the southern end of the Matagorda Peninsula around 10
PM CDT last evening. There have not been any surface observations
of sustained tropical-storm-force winds, and an earlier ASCAT pass
indicated that winds over the water had decreased to near 35 kt.
That is Beta's estimated intensity at the moment, with the
assumption that those winds are still occurring somewhere over
water or within the deep convection near the center.
Beta has been moving northwestward, or 315/3 kt. Steering currents
around the storm are now collapsing, and Beta is expected to
meander during the next 12-24 hours. By this time tomorrow,
however, a mid-level trough over west Texas is forecast to begin
moving eastward and should scoop Beta up, causing the storm to move
toward the east-northeast near or just inland of the upper Texas
coast through 36 hours. After that time, Beta is expected to turn
northeastward, moving farther inland across Louisiana and
Mississippi before dissipating in about 4 days. Because Beta has
moved a little farther inland than expected, much of the model
trackers have shifted northward, and now only the UKMET and its
ensemble mean show Beta's center re-emerging over the extreme
northwestern Gulf of Mexico. The new NHC track forecast has been
adjusted northward accordingly and generally lies between the HCCA
aid and the TVCN multi-model consensus.
Now that Beta's center may not move back out over the Gulf, the
intensity guidance indicates that the cyclone will gradually weaken
during the next few days. However, since a part of the circulation
will remain over water and the system could still produce deep
convection, the NHC forecast shows Beta maintaining tropical storm
status for another 12 hours or so (a scenario which is above all
of the guidance). Beta should weaken to a tropical depression in
about 24 hours, and it is expected to become a remnant low in 2-3
days when vertical shear is expected to be well over 30 kt.
1. Significant flash and urban flooding is occurring and will
continue for the middle and upper Texas coast today. The slow motion
of Beta will continue to produce a long duration rainfall event from
the middle Texas coast to southern Louisiana. Flash, urban, and
minor river flooding is likely. Periods of rainfall will continue
into the ArkLaTex region and spread east into the Lower Mississippi
Valley and portions of the Southeast through the end of the week.
Flash, urban, and isolated minor river flooding is possible.
2. Storm surge flooding will continue throughout the morning, around
the times of high tide along portions of the Texas coast within the
storm surge warning areas. Residents in these areas should continue
to follow advice of local officials.
3. Tropical-storm-force winds will continue near portions of the
Texas coast within the warning area today.
FORECAST POSITIONS AND MAX WINDS
INIT 22/0900Z 28.8N 96.7W 35 KT 40 MPH...INLAND
12H 22/1800Z 28.8N 96.5W 35 KT 40 MPH...INLAND
24H 23/0600Z 29.1N 95.6W 30 KT 35 MPH...INLAND
36H 23/1800Z 29.8N 94.3W 30 KT 35 MPH...INLAND
48H 24/0600Z 30.8N 92.8W 25 KT 30 MPH...INLAND
60H 24/1800Z 32.1N 90.9W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 25/0600Z 33.6N 89.0W 20 KT 25 MPH...POST-TROP/REMNT LOW