Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

FXUS62 KTAE 110536

Area Forecast Discussion
National Weather Service Tallahassee FL
1236 AM EST Wed Dec 11 2019

[Through 06Z Thursday]

Conditions will improve to VFR across the TAF sites by 12Z in the
wake of a cold front. Thereafter expect VFR conditions to continue
through the TAF period. North winds will remain elevated w/ speeds
around 10 knots occasionally gusting to around 20 knots. 



.NEAR TERM [Through Today]...

A cold front will arrive at our western CWA this evening, bringing a 
SW-NE-oriented line of showers and isolated thunderstorms with it. 
The Day 1 Convective Outlook from SPC does not show severe wx at 
this time (just general thunder). Winds should increase some and 
abruptly shift from southwesterly to northwesterly behind this 
system. The frontal boundary will make its complete passage in the 
early-morning hours. As a result, temperatures should be cooler 
tonight, with lows in the mid-to-upper 40s west of Apalachicola 
River and low 50s east of it (overcast skies are also expected 
throughout the near term).

.SHORT TERM [Tonight Through Thursday]...

The cold front will likely have exited much of the region tonight
leading to strong cold air advection behind it across the entire
area. This will cool low temperatures into the mid 40s across our
northern areas, and low to mid 50s across our southern areas.
Although the surface winds are expected to remain northerly to
northwesterly behind the cold front, a southerly component is
expected to remain above the surface flow at the 850hPa layer,
which will enhance isentropic lift over the cooler air. This will
lead to cloudy skies and a small chance of light rain and showers
for much of this period.

.LONG TERM [Thursday Night Through Tuesday]...

A shortwave trough currently approaching the California coastline
is expected to quickly propagate through the southern tier of the
United States. This shortwave trough is expected to interact with
the stalled cold front in the northern Gulf of Mexico that is
currently progressing through our area. Enhanced divergence aloft
coupled with strong baroclinic forcing from the large contrast of 80
degree water temperatures across parts of the northern central 
Gulf of Mexico and the 50-60 degree land temperatures are expected
to aid in the development of a Gulf Low during the day Friday.
SPC currently has a general thunder outlook for Friday; however it
is possible that this threat/outlook may increase to a marginal or
even a slight risk if model guidance trends towards a more
unstable environment with higher CAPE values. Some limiting
factors currently is that there is a lack of instability, and some
model guidance is hinting at a shallow low level inversion, which
would prevent storms from becoming surface based. If this is the
case, most severe storm activity/threat would be limited to
immediate coastal regions. Given that shear profiles are expected
to be veering and provide 30+ knots of sfc-1km shear, it is
certainly possible that an isolated storm or two will be severe. 

In terms of rainfall with the aforementioned system, model 
guidance seems to go back and forth between a wet system for the 
area, to a drier more moderate rain event for the area. This 
uncertainty is likely linked to the models struggling to determine
the overall intensity of the shortwave/surface low pressure 
system and its associated pressure falls expected with the system 
in the northern Gulf before it re- develops along the eastern 
Georgia and South Carolina coastline. Given this uncertainty, a 
widespread 1-3 inches is expected with higher or lower amounts 
locally possible with isolated heavy showers or storms associated 
with the low pressure system. 

Beyond this Friday and Saturday's system, a brief dry period
through the later half of the weekend and early next week is
expected ahead of the next system that will impact the area on
Monday night and Tuesday. Currently, confidence is low on the
impacts and rain totals expected with this system.


A cold front currently moving through the region is expected to
produce a line of showers and isolated storms with it throughout
the day today and tonight. Behind the cold front, winds are
expected to shift to the northerly/northwesterly, and increase to
Small Craft Advisory levels on Wednesday. These levels are
expected to be maintained through the early morning hours on
Friday. A small craft advisory has been issued for our western
waters starting Wednesday morning at 7am EST/6am CDT. Our eastern
waters small craft advisory will begin at 1pm EST/12pm CDT. Seas
will generally increase to 8-9 feet as the stronger 20-25 knot
winds pick up across the waters.


No hazardous fire weather conditions are expected over the next 
few days. Fog is likely.


Even though rainfall chances will be possible from today through
Saturday, no flooding is expected. Generally rainfall amounts will
be in the 1-3 inch rain threshold, which is not enough to cause
flooding concerns given that much of the area is in a dry
conditions to moderate drought.


Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.



Tallahassee   63  46  65  52  68 /  30  30  30  70  70 
Panama City   60  48  63  54  69 /  40  30  40  70  70 
Dothan        58  43  56  47  61 /  40  20  40  80  70 
Albany        60  44  57  47  61 /  30  20  40  80  80 
Valdosta      64  46  64  52  67 /  20  20  30  60  70 
Cross City    71  51  71  57  72 /  20  20  20  40  60 
Apalachicola  63  50  65  56  69 /  40  30  30  70  80 


FL...High Rip Current Risk until 1 AM EST /midnight CST/ early this 
     morning for Coastal Bay-Coastal Gulf-South Walton.

GM...Small Craft Advisory from 7 AM this morning to 1 AM EST Friday 
     for Apalachee Bay or Coastal Waters From Keaton Beach to 
     Ochlockonee River FL out to 20 Nm-Coastal Waters From 
     Ochlockonee River to Apalachicola Fl out to 20 Nm-Coastal 
     waters from Suwannee River to Keaton Beach FL out 20 NM-
     Waters from Suwannee River to Apalachicola FL from 20 to 60 

     Small Craft Advisory until midnight CST Thursday night for 
     Coastal waters from Mexico Beach to Apalachicola FL out 20 
     NM-Coastal waters from Mexico Beach to Okaloosa Walton 
     County Line FL out 20 NM-Waters from Apalachicola to Mexico 
     Beach FL from 20 to 60 NM-Waters from Mexico Beach to 
     Okaloosa Walton County Line FL from 20 to 60 NM.



LONG TERM...Bunker

National Weather Service Glossary of Abbreviations