Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 220332
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1032 PM EST Wed Jan 21 2015
.Near Term [Through Tonight]...
Current fcst is very well on truck with just a few minor tweaks of
raising the overall cloud over (mostly high high across the CWA
overnight...causing little impact on low temperatures. Also,
lowered PoPs from 12-18Z Thursday, just delaying the onset in the
oncoming rainfall slightly.
[Through 00Z Friday] VFR conditions with light winds and just
increasing mid-high cloud cover will prevail through the period.
.Prev Discussion [412 PM EST]...
.Short Term [Thursday Through Friday Night]...
In addition to the dry air spilling in behind the aforementioned
front, zonal flow aloft and high pressure at the surface will
limit rain chances on Thursday. The only exception will be once
easterly flow becomes established over our Gulf waters, where
enhanced convergence along an existing surface trough (seen
clearly on vis imagery) should be enough to generate a few light
showers. These showers will likely remain confined to the Gulf.
Two distinct shortwaves currently present on WV imagery will play
a significant role in our weather Thursday night through Friday
night. The shortwave over the Central Great Basin will merge with
another over the Southwest, resulting in an overall stronger
system as it approaches the Southeast. At the surface, Gulf
cyclogenesis will commence starting Thursday evening, with the low
forecast to track across the northern Gulf, then through the Tri-
State region Friday night.
Ahead of the surface low, a deep warm front is expected to
develop in the strong WAA regime ahead of the low pressure system.
Strong upslope flow will be aided by a large area of diffluent
flow aloft in the amplifying pattern. Further, an infusion of
anomalously high tropical moisture will add to the aforementioned
ingredients to warrant a heavy rain potential. Expect a large
swath of warm frontal rain to spread across the region after
midnight Thursday night, lingering into Friday afternoon. This
will likely result in widespread average rainfall amounts of
around 2 inches preceding the surface low and cold front. Another
inch or so of rain will be possible area-wide with the passage of
the cold front.
As always, the the threat for severe weather around here will
depend on just how much instability exists. While saturating rains
on Thursday night into Friday will result in nearly moist
adiabatic lapse rates, a strong focused low level jet could result
in shear profiles favorable for tornadic development. Whether
these storms could get surface based would be the main question,
though it appears at least possible. Probably the best threat for
any sort of severe weather would be late Friday afternoon into
Saturday evening over the eastern Big Bend of Florida, where more
favorable instability will align with strong deep layer shear. At
this time the low-level jet wont be quite as strong and the threat
would most likely shift to a damaging straight line wind
potential. At this time, the potential for severe weather Thursday
night through Friday night appears to be quite low, with high
.Long Term [Saturday Through Wednesday]...
In the wake of the aforementioned system, dry conditions will
prevail through mid-week next week. Temperatures look to remain
near seasonal levels both afternoon and night.
Easterly flow will commence tonight, with winds and seas
increasing to advisory levels Thursday night ahead of a strong
frontal system. Gusts could reach gale force late Thursday night
through Friday afternoon. Advisory conditions will continue
through Saturday in the wake of the front, though gust should fall
back below gale levels. Only a brief fall from headline levels
will occur Saturday night into Sunday morning before another
system threatens advisory conditions to end the weekend.
Moisture will increase as a low pressure system in the Gulf moves
through. A wetting rain is expected Thursday night into Friday.
Dispersions are low as transport winds will be light on Thursday.
No fire weather concerns at this time.
All area rivers remain below flood stage with steady or decreasing
water levels. The forecast 2-3 inch rainfall amounts Thursday
night through Friday night would result in rising river levels,
though only rivers impacted by the isolated higher rainfall
amounts would risk reaching flood stage.
.Preliminary Point Temps/PoPs...
Tallahassee 47 68 58 65 49 / 0 0 70 90 50
Panama City 50 64 58 64 49 / 0 10 80 90 40
Dothan 44 60 51 55 43 / 0 10 80 90 40
Albany 41 61 49 55 46 / 0 0 80 90 50
Valdosta 46 66 56 63 51 / 0 0 60 90 70
Cross City 50 73 58 68 56 / 0 0 30 80 80
Apalachicola 50 65 58 66 52 / 0 10 70 90 40