Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 061124
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
624 AM EST Thu Mar 6 2014
[Through 12z Friday] Rather poor conditions will continue through
the period with prevailing IFR/LIFR cigs and widespread rain as an
area of low pressure develops south of the area. Rain may decrease
some during the afternoon around KDHN and KECP with a potential
dry slot, but conditions are expected to remain below VFR through
the period. Winds could be gusty at times today, especially at
KDHN and KABY.
.Prev Discussion [228 AM EST]...
.Near Term [Through Today]...
The wet forecast remains on track for today as a vigorous upper
level trough digs into the southeast states. The associated surface
low is expected to deepen today across the northeast Gulf and move
inland across the FL peninsula. This will keep our forecast area on
the cool side of the system with ENE flow. Some elevated instability
exists above the cool, stable layer near the surface, so a few
rumbles of thunder remain possible from near I-10 southward. A dry
slot may develop and move eastward into the western zones this
afternoon, causing the rain coverage there to decrease and become
more showery. The PoP forecast reflects this thinking with 100 PoPs
everywhere through the morning, then decreasing across the west in
the afternoon. With ENE surface flow today, high temperatures will
.Short Term [Tonight Through Saturday]...
The 500 mb flow pattern will become a bit more amplified/phased,
which will put an end (for the time being) to the systems that
have been training quickly along the Gulf Coast this past week. By
tonight a large, intense dry slot will be wrapping around most of
the 500 mb low, which will be propagating slowly east-
northeastward over GA. It`s curious that all of the various
dynamical models and MOS forecast such high PoP and relatively
high QPF for our forecast area tonight and early Friday, as the
vast majority of the time when we get "dry slotted" the rain just
stops. In particular, the 00 UTC GFS QPF bullseye over southwest GA
(with an inch of rain) would be unprecedented for this type of
synoptic pattern. Based on the climatology of these systems, we`ve
undercut the guidance consensus PoP and QPF a bit, though that
still leaves much of our region with a 50-60% PoP overnight. The
rain will end from west to east during the day on Friday, but the
SREF ceiling guidance holds on to the cloud cover until later
Friday afternoon. This, along with the relatively cold nature of
this system, will keep highs below average on Friday (lower to mid
50s around Tifton, upper 50s to lower 60s elsewhere). 500 mb
heights will rise dramatically Friday night and Saturday, as an
area of surface high pressure becomes centered over our region.
With clearing skies, calm winds, and a dry boundary layer, lows
will fall into the upper 30s in the normally colder inland
locations away from the beaches Friday night. On Saturday a
warming trend will begin, with highs in the lower 70s (mid 60s at
the beaches, as the Gulf waters are still rather cool).
.Long Term [Saturday Night Through Thursday]...
We should finally see some warming to around normal levels.
Unsettled weather will move back into the area by mid week ahead
of yet another system. There remain differences between the
operational GFS and Euro with this next system as the Euro phases
with a nrn stream impulse and GFS does not. However, both bring
another shot of rain during the mid week period. Expect highs in
the 70s through mid week.
Some of the NWP guidance has underestimated the wind speeds over our
coastal waters this early morning, which they tend to do sometimes
when there is a high pressure "wedge" just to our north and a
quasi-stationary front (with developing frontal cyclone) to our
south. In fact, winds were very close to advisory levels. We relied
more on the higher-resolution NWP guidance for today, as these
models have verified a little better thus far. Winds will weaken
slightly this afternoon, but still remain at moderate levels from
the north or northeast through Friday. Much lower winds and seas are
expected this weekend as an area of high pressure becomes centered
over the marine area.
Red flag conditions are not expected over the next several days,
though dispersions will remain low today with widespread rain.
Most of the rainfall on Wednesday was 0.25 in or less, with
isolated amounts between 0.50 to 1.0 in. Rainfall totals for this
next system (today through Friday) will average between 1.0 and
1.5 inches, with the heaviest amounts likely across the FL Big
Bend and South Central GA. These amounts are unlikely to cause
flash flooding, even though isolated heavier amounts could cause
some standing water in poor drainage areas. However, this will add
a fairly large volume of water to several rivers that already
exhibited above-normal flow. The latest GFS, CMC, and SREF based
hydrologic ensembles (MMEFS) continue to forecast several sites to
reach action stage over the next several days. This is a common
scenario this time of year when there is an El Nino pattern. This
means that many of the local rivers will essentially be "primed"
for flooding, if they get another round(s) of soaking rain in the
next week or two.
.Preliminary Point Temps/PoPs...
Tallahassee 53 43 57 38 70 / 100 60 20 0 0
Panama City 55 43 61 48 67 / 100 50 10 0 0
Dothan 47 38 58 41 71 / 100 60 20 0 0
Albany 45 38 54 40 71 / 100 60 40 0 0
Valdosta 50 41 55 40 70 / 100 60 40 0 0
Cross City 59 46 61 38 71 / 100 40 20 0 0
Apalachicola 60 44 61 47 66 / 100 50 10 0 0
GM...Small Craft Advisory until 5 PM EST this afternoon 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.