Tropical Storm Francine Forecast Discussion Number 9

By | September 10, 2024

000
WTNT41 KNHC 102038
TCDAT1

Tropical Storm Francine Discussion Number   9
NWS National Hurricane Center Miami FL       AL062024
400 PM CDT Tue Sep 10 2024

The convection associated with Francine has not changed much in 
organization during the past six hours.  Radar data from the 
WSR-88D Doppler radar in Brownsville shows good curved banding 
around the center, but the convection is having trouble persisting,
possibly due to continued dry air entrainment.  Reports from an Air 
Force Reserve Hurricane Hunter aircraft prior to 18Z showed that 
the central pressure had dropped to near 987 mb, and that the 
maximum 700-mb flight-level winds were 63 kt.  Based on these data 
and satellite intensity estimates from SAB and TAFB, the initial 
intensity is set at 55 kt.

The initial motion is now 035/9 kt.  An approaching mid-latitude 
shortwave trough over Texas should cause the storm to move 
northeastward at a faster forward speed during the next 24-36 h, 
and this motion should bring the center to the Louisiana coast 
sometime Wednesday afternoon or evening.  After that time, Francine 
should turn more northward between the trough and a mid-level ridge 
over the eastern United States.  While there is little change to 
the track forecast scenario since the last advisory, the track 
guidance has again shifted to the east, most notably between   
12-48 h.  Based on this change, the forecast track during that 
period is again nudged a little to the east.  The new track lies 
just to the left of the various consensus models.

Francine has about 24 h to strengthen over warm water before it 
encounters strong shear near the Louisiana coast.  While there 
remains a possibility that dry air entrainment could continue to 
reduce the intensification rate, the intensity forecast continues 
to call for steady to rapid strengthening during this time based on 
the otherwise favorable conditions, and the forecast peak intensity 
of 80 kt is at the high end of the intensity guidance.  
Intensification is expected to stop near or just before landfall, 
and rapid weakening is expected after landfall.  The global models 
continue to show the remnants of Francine dissipating after 96 h, 
and the intensity forecast again follows that scenario. 

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 the 
Louisiana and Mississippi 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 and urban flooding across eastern Louisiana,  
Mississippi, far southern Alabama and the western Florida Panhandle 
through Thursday.  Flash and urban flooding is probable across the 
Lower Tennessee Valley and Lower Mississippi Valley Wednesday night 
into Friday morning.


FORECAST POSITIONS AND MAX WINDS

INIT  10/2100Z 25.7N  95.0W   55 KT  65 MPH
 12H  11/0600Z 26.9N  94.0W   65 KT  75 MPH
 24H  11/1800Z 28.9N  92.0W   80 KT  90 MPH
 36H  12/0600Z 31.0N  90.6W   55 KT  65 MPH...INLAND
 48H  12/1800Z 33.4N  89.8W   30 KT  35 MPH...INLAND
 60H  13/0600Z 35.3N  89.8W   25 KT  30 MPH...INLAND
 72H  13/1800Z 36.1N  89.8W   20 KT  25 MPH...POST-TROP/REMNT LOW
 96H  14/1800Z 37.5N  89.5W   20 KT  25 MPH...POST-TROP/REMNT LOW
120H  15/1800Z...DISSIPATED

$$
Forecaster Beven

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