Tropical Storm Francine Forecast Discussion Number 7

By | September 10, 2024

921 
WTNT41 KNHC 100849
TCDAT1

Tropical Storm Francine Discussion Number   7
NWS National Hurricane Center Miami FL       AL062024
400 AM CDT Tue Sep 10 2024

Francine has not become appreciably better organized overnight.  
There is a large cluster of cold-topped convection located well to 
the northeast of the center, but the central deep convection is 
still not very strong.  Some banding features appear to be 
developing over the northeastern portion of the circulation.  The 
advisory intensity is held at 55 kt for now, in agreement with 
earlier data from an Air Force Hurricane Hunter aircraft, and a 
subjective Dvorak Current Intensity number from TAFB.  Objective 
Dvorak intensity estimates from UW-CIMSS are a little lower.  Air 
Force and NOAA Hurricane Hunter aircraft are scheduled to 
investigate the storm in a few hours and should provide a good 
estimate of Francine's intensity.

Center fixes from an Air Force Hurricane Hunter aircraft and ASCAT 
data showed little motion a few hours ago, but recent satellite 
imagery suggest a slow north-northwestward motion at around 340/4 
kt.  The general steering scenario for the next couple of days 
remains about the same as in the previous advisory.  Francine should 
move mostly northward today along the western periphery of a mid 
level high over the southeastern Gulf of Mexico.  By late tonight, a 
shortwave trough over Texas is expected to cause a turn toward the 
northeast with an increase in forward speed.  This motion should 
bring the center of the system to the Louisiana coast tomorrow 
afternoon or evening.  The model tracks are in fairly good agreement 
on this scenario, although there is still some cross- and 
along-track spread.  The official track forecast in the 36- to 
48-hour time frame has been nudged just a few tenths to the east of 
the previous one, and lies between the ECMWF solution and the 
multi-model consensus prediction.

The tropical cyclone should be over very warm waters before 
landfall, although west-southwesterly vertical wind shear over the 
system is likely to increase.  The latter environmental influence 
will probably limit Francine's strengthening.  Nonetheless, the 
SHIPS-RI Index shows a significant probability of at least a 25-kt 
increase in maximum winds during the next 24 hours.  The official 
intensity forecast is now at the high end of the model guidance.

An experimental cone graphic that includes inland Hurricane and
Tropical Storm Watches and Warnings in the U.S. is now available on
the NHC website. Due to the time needed to compile the inland watch
and warning information, the experimental cone graphic will not be
available as quickly as the operational cone. Once it is available,
the experimental cone graphic can be found from a red weblink above
the operational cone graphic at
www.nhc.noaa.gov/graphics_at1.shtml?cone#contents. Users are
encouraged to take the experimental product survey found below the
experimental cone.

KEY MESSAGES:

1. There is a danger of life-threatening storm surge for portions
of the Upper Texas and Louisiana coastlines where a Storm Surge
Warning is in effect.  Residents in the warning area should follow
advice, including evacuation orders, given by local officials.

2. Damaging and life-threatening hurricane-force winds are expected
in portions of southern Louisiana Wednesday, where a Hurricane
Warning is in effect. Preparations to protect life and property
should be complete by tonight, since tropical storm conditions are 
expected to begin within this area early Wednesday.

3. Francine is expected to bring heavy rainfall and the risk of 
considerable flash flooding for much of Louisiana and Mississippi 
through Thursday.  Flash and urban flooding is probable across 
portions of northeast Mexico and far southern Texas into early 
Wednesday, and the Mid-South Wednesday night into Friday morning.


FORECAST POSITIONS AND MAX WINDS

INIT  10/0900Z 24.4N  96.2W   55 KT  65 MPH
 12H  10/1800Z 25.4N  95.6W   70 KT  80 MPH
 24H  11/0600Z 27.1N  94.2W   80 KT  90 MPH
 36H  11/1800Z 29.0N  92.5W   85 KT 100 MPH
 48H  12/0600Z 31.4N  91.1W   50 KT  60 MPH...INLAND
 60H  12/1800Z 33.8N  90.5W   30 KT  35 MPH...INLAND
 72H  13/0600Z 35.7N  90.2W   25 KT  30 MPH...POST-TROPICAL
 96H  14/0600Z 37.0N  90.0W   20 KT  25 MPH...POST-TROPICAL
120H  15/0600Z...DISSIPATED

$$
Forecaster Pasch


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