Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 120842
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
442 AM EDT Wed Jun 12 2013
.NEAR TERM [Through Tonight]...
With upper level ridging continuing to nose in from the west, SFC
ridging parked just to our south, and NW synoptic flow at the lower
levels, plenty of daytime insolation should allow for one of the
hottest days of the season thus far. High temps are expected to
climb into the upper 90s over much of the interior, with lower 90s
restricted to the immediate coast. In fact, the usual hot spots like
Valdosta may experience their first 100 degree day this year. Heat
indices will also be on the rise, but afternoon dewpoints should mix
out enough to keep them below Advisory levels. Nevertheless,
maximum Heat Indices of around 105 degrees will be quite
uncomfortable. As for rain chances, the 1000-700mb Mean Layer Vector
Wind (MLVW) will be out of the NW today, which is a Type 8 Regime in
our local Sea Breeze Climatology (reference
www.srh.noaa.gov/tae/?n=seabreeze for details). In short, this
Regime tends to keep the Sea Breeze Front pinned near the coastline
until later in the afternoon, but also increases vertical motion
along the front, which can result in stronger storms given a
favorable environment. For this afternoon, we are only forecasting
20% PoPs across much of the FL Big Bend and Panhandle (with silent
10s elsewhere), which is essentially a blend of our local Confidence
Grids and CAM (Convective Allowing Models) output. These PoPs are
also lower than a typical Type 8 Regime due to less favorable deep
layer thermodynamics. However, any storms that do develop may
contain brief gusty winds. For tonight, did not carry over any PoPs
at this time, although this always carries some risk in Regime 8 due
to the usual late start of the convection. Additionally, some of the
Hi-Res models are hinting at potential MCS development to our N and
NE which will have to be monitored as well.
.SHORT TERM [Thursday Through Friday Night]...
The main focus for the short term period will be the potential for
severe weather in our CWA. The SPC Day 2 Outlook has our far
nothern Florida counties and all of our Georgia and Alabama
counties under a slight risk, but our entire CWA is under at least
a 5% probability of severe weather.
Deep layer ridging to the west and troughing to the east will
continue to keep our CWA in a northwest flow regime. Northwest
flow will keep our entire CWA drier than average and warmer than
average. A shortwave is expected round the base of the trough and
pivot through our area beginning Friday morning. This type of
synoptic pattern is conducive for MCS development/maintenance. Low
level CAPE and shear values seem conducive for new cell
development to maintain multicellular thunderstorm complexes. The
advancing afternoon sea breeze of Friday will also likely enhance
any thunderstorms that are present.
Other than the chance for severe weather the remaining short term
period will be characterized by above average temperatures, below
averages humidities, and low chances for rain.
.LONG TERM [Saturday through Wednesday]...
Continuing from the short term, we have a frontal system possibly
reaching our area around Thursday night and exiting to the southeast
by overnight Friday night. Rain chances will stay low once again
thanks to high pressure aloft and at the surface, although some
convection from the sea-breeze may be possible. Monday through
Tuesday rain chances increase again as another shortwave moves
through with a similar setup to the Thursday-Friday rain chances.
Highs in the 90s and lows in the 70s are expected through the period.
[Through 12 UTC Thursday] With the recent influx of drier air from
the northwest, VFR conditions should prevail at the terminals
through the period. However, did go with brief periods of low end
MVFR Cigs at ECP and TLH (based on input from the HRRR guidance)
overnight and a period of MVFR level Vis at VLD. During the day,
isolated afternoon thunderstorms will again be possible with the Sea
Breeze Front, but PoPs are too low for mention in any of the Tafs at
this time. That said, with the northwesterly flow, the best chances
for an afternoon storm would be at ECP and TLH.
Light winds and relatively calm seas are expected until a frontal
system approaches to our north beginning late Thursday night/early
Friday morning when cautionary levels will be possible. By Friday
night, winds are expected to weaken to below cautionary levels.
Although the generally hot and dry weather will continue, conditions
are not expected to approach Red Flag levels airmass will be a bit
drier today and Wednesday than in recent days, Red Flag conditions
are not expected.
After the recent heavy rainfall across the area, two river points
are at or expected to reach Action Stage. The Ochlockonee River near
Thomasville is at Action stage, and will crest early Friday morning
then start to recede. The Little River near Hahira is expected to
reach Action Stage early Monday morning. With little precipitation
expected over the next couple of days, impacts to area rivers will
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 98 72 96 74 94 / 20 10 20 20 30
Panama City 92 76 91 78 91 / 20 10 20 20 30
Dothan 98 74 99 74 95 / 10 10 10 20 20
Albany 98 74 99 74 93 / 10 10 10 30 20
Valdosta 100 72 99 73 92 / 10 10 20 30 30
Cross City 95 72 93 74 91 / 20 10 20 10 30
Apalachicola 91 75 89 77 90 / 20 10 10 10 30