Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 121857
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
257 PM EDT Sun May 12 2013
.NEAR TERM [Through Monday]...
The highly amplified long wave pattern persists across North America
this afternoon with a trough dominating the eastern half of the
continent. Surface low pressure is centered over New England with
a cold front trailing southwestward from it. The southern end of
this front is still moving slowly across the southeastern FL Big
Bend. A second front is poised to enter our northwestern zones. A
few of the convection allowing models, including our local WRF,
continue to show isolated showers developing along and just ahead of
the lead front around or shortly after 18Z. We will therefore leave
in a small area of 20 PoPs for Taylor, Lafayette and Dixie Counties.
Any showers that develop will dissipate by sunset. The second front
will surge across the forecast area overnight bringing another
unseasonably cool airmass to the Gulf Coast. Lows tonight will drop
8-12 degrees below normal along and north of I-10 with many areas
north of the FL border actually dipping into the upper 40s. The very
dry airmass will allow temps to warm quickly after sunrise. However,
temps will still be below normal peaking in the upper 70s to around
80 degrees. All in all, it should be a very pleasant day.
.SHORT TERM [Monday Night Through Wednesday]...
The deep upper level trof pushing the cold front through today will
lay over the mid-Atlantic states by Monday night and an upper level
ridge will be building eastward over our area through the period.
High pressure at the surface and aloft through the period will give
us clear skies. Monday night will be a little chilly with lots of
radiational cooling allowed from the clear skies in addition to the
presence of a much colder air mass. Lows will dip into the mid-upper
40s across the region. Tuesday the clear skies will allow us to warm
up again to the low 80s. Lows Tuesday night will be in the 50s and
highs Wednesday will be in the low-mid 80s.
.LONG TERM [Wednesday Night through Saturday]...
Although models are showing upper level ridging at 300 mb that stays
in place through the period, they also show a mid-level short wave
impulse at 500 mb that will propagate through the weak ridging. This
may cause some convection this weekend, particularly during daytime
hours with solar heating to aid it, but the models are not showing
high rain chances overall this weekend, with PoPs highest on
Saturday and Sunday during the day with values <30%. Temperatures
will be about normal for this time of year.
.AVIATION [Through 18Z Monday]...
VFR conditions are forecast throughout this TAF period. VFR
ceilings of 4-5 kft are expected this afternoon at TLH and VLD.
The main aviation impacts on Monday will be the gusty north winds.
Behind the dry cold front passage, the pressure gradient will
increase and winds will pick up to advisory levels over the coastal
waters from west to east overnight. Waves will increase to as high
as 5 feet offshore. Winds will begin to settle down to cautionary
levels from north to south through Monday morning through Monday
night and after that, winds and seas will remain below advisory
level for the rest of the period.
A drier air mass has arrived behind a cold front across all but
southern and eastern portions of the FL Big Bend. However, red flag
criteria will not be threatened. On Monday, red flag conditions are
definitely a possibility across a few of our FL zones, namely Bay,
Calhoun, Leon and Wakulla. It will definitely be dry enough with min
RH getting into the upper teens and lower 20s. Winds will be
marginal, but observed ERC levels are high enough in the
aforementioned counties. We will mention these caveats in the
remarks, but winds are too marginal to go with a watch or warning at
this time. Red flag conditions are unlikely in Alabama and Georgia
due to insufficient KBDI and fuel moisture requirements respectively.
Rainfall totals on Saturday were minuscule, so we don`t expect any
hydrology issues for the next several days.
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 83 52 80 44 81 / 10 0 0 0 0
Panama City 80 56 79 57 79 / 10 0 0 0 0
Dothan 81 50 78 50 83 / 0 0 0 0 0
Albany 81 49 78 47 82 / 0 0 0 0 0
Valdosta 84 51 77 46 80 / 10 0 0 0 0
Cross City 82 57 81 46 81 / 20 10 0 0 0
Apalachicola 80 57 78 54 77 / 10 10 0 0 0
GM...SMALL CRAFT ADVISORY from 2 AM to 2 PM EDT Monday for Waters
from Suwannee River to Apalachicola FL from 20 to 60 NM-
Waters from Apalachicola to Destin FL from 20 to 60 NM.