NATIONAL WEATHER SERVICE TALLAHASSEE FL
230 PM EST Sat Dec 28 2013
NEAR TERM [Through Tonight]...
Surface analysis shows that the advertised low has developed in the
Gulf and was about 130 miles SSW of Pensacola at 18z.
This feature combined with deep layer moisture and large scale ascent associated with upstream shortwave is generating widespread rains across the central Gulf coast.
Most of this activity has stayed just to the west of our CWA as of 18z.
However, as the low continues to develop and lift northeastward into the panhandle tonight, rain and even a few thunderstorms will overspread the entire Tri-state region and PoPs have been raised to 100% for the overnight hours.
The best chance for a thunderstorm will in the Florida zones from around Panama City eastward as this region enters the warm sector after 00z. In the coastal area there continues to be a low threat for one or two storms to briefly become strong to severe. The main threat would be damaging wind gusts or a brief tornado.
Otherwise, we do expect rain to be heavy at times, with average rainfall amounts expected to be around 1-2" over most of the area.
Given fairly high flash flood guidance, we do not anticipate widespread flooding issues. Localized flooding, primarily of urban areas, will be possible in the aforementioned areas where locally heavy rain is expected.
SHORT TERM [Sunday Through Monday Night]...
The surface low will be crossing the Savannah River from GA into SC
by sunrise Sunday.
The cold front will clear the Valdosta area and our eastern FL Big Bend zones by around 15z. Isolated thunderstorms will be possible in the warm sector ahead of the front.
We generally undercut operational MOS max temps due to extensive morning cloud cover followed by CAA. Look for temps to peak around 60 far northwest to the lower 70s far southeast.
The airmass behind the front is of Pacific origin, so temps will not drop off much behind it. In fact, temps will remain a few degrees above normal Sunday night through Monday night.
A passing short wave may bring a few sprinkles to the area Monday night.
LONG TERM [Tuesday Through Saturday]...
Broad cyclonic upper level flow will remain in place over the eastern U.S. into Friday with zonal flow returning by the weekend.
Short waves will continue to flow through the trough. One will be
exiting the area Tuesday morning with clearing skies to follow.
The models have been having difficulty handling the evolution of the
next wave in the pipeline, currently over Southern CA, with run-to-run inconsistencies. That said, the 12z suite of guidance is generally in agreement now in showing the energy shearing out before moving east of TX.
This is in contrast to some earlier runs (including the 00z Euro) that showed a sharper system inducing cyclogenesis in the Gulf of Mexico. The latest Euro still shows some development, but it is much weaker.
With this development now reduced or lacking altogether, lower PoPs in the Wednesday through Thursday time frame now seem justified and some modifications were made to that effect.
Max temps will generally be a couple of degrees below normal through the period and there appears to be some chance for a freeze Friday night.
IFR/LIFR cigs will prevail through the TAF period.
Likewise, expect vsbys to lower into the MVFR/IFR range as rain overspreads the region from west to east later this afternoon and prevail at these levels through the overnight hours.
Rain will be heavy at times, and isolated thunderstorms will be possible, mainly at the ECP and TLH terminals later this evening through daybreak Sunday.
Winds will shift to become northwest in the wake of the cold front Sunday morning but the low overcast will linger into the afternoon.
Low pressure developing over the north central Gulf of Mexico this
afternoon will move ashore into the Florida Panhandle tonight
bringing advisory level onshore winds to the forecast area.
The low will lift northeast of the area early Sunday and drag a cold front across the waters.
Winds will shift to the northwest and diminish behind the front as high pressure builds eastward.
Northerly winds may briefly reach cautionary levels Monday night into Tuesday morning with light to moderate northeast winds expected through the midweek period.
Red flag conditions are not expected for the foreseeable future.
The Apalachicola River is above flood stage and is forecast to remain in minor flood stage through at least January 2nd with releases from Woodruff Dam. The river is forecast to crest Thursday afternoon at 17.8 feet.
Other area rivers and creeks are elevated but remain below flood stage at this time.
Rainfall this weekend is expected to average in the 1-2" range.
This will keep river levels elevated, but widespread flooding is not expected.
PRELIMINARY POINT TEMPS/POP...
Tallahassee 61 69 44 67 44 / 100 50 10 10 30
Panama City 59 65 48 65 46 / 100 20 10 20 30
Dothan 51 61 41 62 40 / 100 20 10 10 30
Albany 56 65 42 64 40 / 100 40 10 10 30
Valdosta 63 70 44 66 42 / 100 70 10 10 30
Cross City 65 72 47 69 46 / 100 80 10 20 30
Apalachicola 62 68 49 64 48 / 100 40 10 20 30
GM...Small Craft Advisory until 10 AM EST Sunday for Apalachee Bay-
Coastal waters From Ochlockonee River to Apalachicola FL out to 20 NM-Coastal waters from Suwannee River to Keaton Beach FL out 20 NM-Coastal waters from Apalachicola to Destin FL out 20 NM-Waters from Suwannee River to Apalachicola FL from 20 to 60 NM-Waters from Apalachicola to Destin FL from 20 to 60 NM.