NEAR TERM [Today and Tonight]...
The high-resolution model guidance appears to have been reasonably accurate in depicting an increase in convective coverage and rain rates around 06-08 UTC. The showers that have developed so far appear to be dominated by warm rain processes - low-topped
convection that is very efficient in producing rainfall. The TLH
airport recorded around one half inch of rain in just under a half
hour with one of these showers.
The HRRR and preponderance of CAM guidance shows a general 1-2" of rain on average can be expected through mid-afternoon over most of our Florida zones (where the heaviest rain is most likely). However, the vast majority of those models also show localized amounts in the 7-9" range, which would likely be sufficient to cause localized flash flooding. Because of this, we have issued a Flash Flood Watch in effect until 23 UTC for all of our Florida zones.
PoPs were adjusted to show 60-80% values this morning across our
Florida zones, with "likely" PoPs (60-70%) spreading north into our
Alabama and Georgia zones later this morning and afternoon. The
abundance of rain and cloud cover will likely once again restrict
the diurnal temperature range, so high temperatures were kept cooler
than normal values, and similar to the inherited forecast. Indications are that convective coverage will diminish between 21 and 03 UTC, with a lull Saturday evening.
SHORT TERM [Sunday Through Monday]...
While at this time yesterday it had appeared that there would be
some legitimate hope that a brief period of upper level ridging
could push far enough northward in the Gulf of Mexico to at least
give our region a brief break in the unsettled weather, each
consecutive run of the ECMWF continues to squash that little bit of
If the Upper ridge stays weak and in the Central Gulf of Mexico, the probability of conditions that are wetter and cooler than climo will increase, and for those looking for a break in the persistent Upper trough (and accompanying sunnier and drier conditions) may have to wait until next summer.
LONG TERM [Monday Night through Friday]...
The GFS and ECMWF forecast a 500mb trough to develop over the
Southeast over the upcoming work week. It`s difficult to forecast
specifics in such patterns as there will undoubtedly be minor short
waves rotating through this broader trough, which can help trigger
periods of active deep moist convection (sometimes even overnight).
The best approach is to "broad brush" above-average rain chances
(generally 50-60% each day, and 20-30% each night) across the
region, which is near the GFS-ECMWF MOS PoP blend.
Temperatures will be near average, with highs in the lower to mid 90s (inland) and lows in the 70s.
AVIATION [through 12 UTC Sunday]...
Some IFR-MVFR CIGS could develop at our three northern terminals
(DHN, ABY, VLD) out ahead of the rain showers that are developing
near the Gulf. These will likely diminish as the rain advances north
Meanwhile, MVFR-VFR should prevail at TLH and ECP, with tropical rain showers having the potential to reduce visibility at times to IFR.
These tropical rain showers will spread inland during the day, with the potential to eventually affect the remaining terminals (ABY, DHN, VLD).
Rain will diminish by 21-03 UTC with VFR through the evening.
Moderate onshore winds today have created slightly higher seas than
expected, so did bump up seas about 1 foot across the board for
Winds and seas will diminish a bit back to more typical summertime levels on Sunday and Monday, before becoming moderate again out of the west by mid week, as the surface pressure pattern increases slightly.
Red flag conditions are not expected for the next several days.
Numerous tropical rain showers and rain bands are beginning to
develop early this morning in a very moist environment. The humid
air mass is due to a large plume of tropical moisture.
A variety of model guidance shows a general inch of rainfall averaged across all of the Florida panhandle and big bend. However, there are also indications that localized amounts could be well in excess of that.
Small heavy rain bands are not uncommon in a tropical environment
such as this, and they can lead to localized flash flooding.
The rain should begin to decrease in coverage closer to sunset.
Impacts on area rivers are difficult to pinpoint at this time, but certainly
areas near Bruce, Lamont, and Newport in Florida should be on alert
for potential rises back to Flood Stage.
PRELIMINARY POINT TEMPS/POPS...
Tallahassee 84 73 90 74 91 / 80 30 60 30 40
Panama City 84 76 88 76 88 / 70 50 60 30 40
Dothan 87 73 90 73 91 / 70 30 60 30 50
Albany 87 73 91 74 91 / 70 30 60 30 50
Valdosta 85 72 92 73 92 / 70 30 60 30 50
Cross City 88 73 90 73 90 / 60 30 60 20 40
Apalachicola 84 76 88 75 88 / 70 50 50 20 40
FL...FLASH FLOOD WATCH through this evening for Calhoun-Central
Walton-Coastal Bay-Coastal Dixie-Coastal Franklin-Coastal Gulf -Coastal Jefferson-Coastal Taylor-Coastal Wakulla- Gadsden-Holmes-Inland Bay-Inland Dixie-Inland Franklin- Inland Gulf-Inland Jefferson-Inland Taylor-Inland Wakulla- Inland Walton-Jackson-Lafayette-Leon-Liberty-Madison- South Walton-Washington.