Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 292143
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
443 PM EST Thu Jan 29 2015
.Near Term [Through Tonight]...
A shortwave trough can be seen clearly via WV imagery, embedded
within a wavy longwave trough across the eastern half of the
country. The shortwave is currently located over the Middle
Mississippi Valley and is forecast to reach the Mid-Atlantic coast
by morning. The deep synoptic forcing from this shortwave will
remain north of the Tri-State region. However, a surface cold front
that is currently draped southwest to northeast from the Southern
Plains through the Lower Mississippi Valley will be pushed through
the region as the aforementioned wave moves east. The front is
currently characterized by a sharp dewpoint gradient, with a broad
temperature gradient spread over 100-200 miles. There is fair
consensus that the cold air will catch up to the front at some point
during its passage across the local area. This will create a zone of
stronger forcing in the 1000-850mb layer and result in a more
organized line of light showers. So, while there is little to no
precip this far south along the front at this hour, expect it to
fill in a bit more late tonight into tomorrow morning. QPF amounts
should remain low, likely below a tenth of an inch.
.Short Term [Friday Through Saturday Night]...
In the upper levels a deep trough will be over the Atlantic Seaboard
on Friday. At the sfc, a weak cold front will pass through the
region by late Friday morning. There will be only a slight chance of
rain Friday morning for the Big Bend Region and offshore. By Friday
afternoon, skies will clear out and northerly winds will bring cool,
dry air to the region once again. Highs will be in the lower 60s for
most locations on Friday. Clear skies and northerly flow will make
for a chilly night Friday night with lows in the low to mid 30s
expected. Saturday will be mostly sunny and slightly warmer as winds
become more easterly as high pressure is over the Southeast. Highs
will be in the low to mid 60s at most locations. Clouds will begin
to move in late Saturday as a large trough extending from the Great
Plains through Baja California provides large-scale lift and
moisture over the Mississippi River Valley. Lows Saturday night will
be in the lower 40s.
.Long Term [Sunday Through Thursday]...
On Sunday, an upper level trough is moving into the Upper
Mississippi Valley and a cutoff low remains over Baja
California/Northern Mexico. At this time, a low will develop over
the Lower Mississippi Valley at the sfc. Large batches of rain will
be likely well ahead of the cold front with abundant Gulf moisture
present. Therefore, rain is likely Sunday into Sunday night. By
Monday morning, rain will be moving out and high pressure will be
moving in bringing cooler, drier air. By Tuesday night, a sfc low
will form over the Gulf near Texas and Louisiana. Therefore, clouds
will begin to move in. This low will track to the northeast bringing
high rain chances once again by Wednesday. Thursday afternoon, high
pressure will once again build into the region bringing cooler,
drier air. Highs will be in the 50s and 60s, changing almost daily
due to the active weather pattern. Lows will range from the low 30s
to the mid 50s.
[Through 18Z Friday]
VFR conditions will fall to MVFR levels under ceilings from west
to east through the night ahead of an approaching front. Behind
the front skies will return to VFR levels. All terminals should
return to VFR by mid-morning tomorrow.
Winds will increase and become northerly late tonight as a cold
front passes. Advisory conditions are likely in the morning hours
tomorrow in the western half of the waters. An active weather
pattern will bring moderate winds off and on throughout the week and
advisory conditions possible once again Monday morning.
A cold front will usher in some slightly cooler, drier air to our
region Friday and Saturday. Although RH values may approach locally
critical levels on Saturday afternoon, we currently do not expect
Red Flag conditions as other values (i.e. ERC, wind, RH duration,
etc.) will not be favorable.
The Ochlockonee River has crested through Concord this morning
with Havana likely to crest in the next 24 hours just above flood
stage. The Withlacoochee below Valdosta is still rising and will
likely crest around 18.5 feet early on Friday at the US-84 gage,
just below flood stage. Aside from the Havana and US-84 sites
being around flood stage, no further river flooding from last
week`s rainfall is expected.
Streamflows remain above to well above normal across the entire
region. Overall rainfall from Sunday`s storm system shouldn`t
exceed 1.5 inches across any particular basin, suggesting little
or no river flood threat. However, this rainfall will slow the
rate of recession across area river basins and possibly set the
stage for river flooding late next week should the heavier
rainfall solution with Wednesday`s storm materialize.
.Preliminary Point Temps/PoPs...
Tallahassee 46 63 34 64 43 / 20 10 0 0 0
Panama City 50 61 38 60 48 / 20 10 0 0 10
Dothan 40 58 32 59 43 / 20 10 0 0 10
Albany 42 60 30 59 41 / 20 10 0 0 0
Valdosta 43 62 33 64 43 / 10 10 0 0 0
Cross City 47 68 34 67 44 / 10 20 0 0 0
Apalachicola 54 64 39 61 49 / 20 20 0 0 10
GM...Small Craft Advisory from 4 AM to 1 PM EST Friday for Coastal
waters from Apalachicola to Destin FL out 20 NM-Waters from
Apalachicola to Destin FL from 20 to 60 NM.