Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 221421
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
921 AM EST Thu Jan 22 2015
...Locally heavy rain possible on Friday...as well as a low risk
of a severe storm...
.Near Term [Through Today]...
The 7 am EST regional surface analysis showed a rather ill-
defined, quasi- stationary front from the SC coast through north
FL, extending westward to the TX coast. Vapor imagery and upper
air data showed a potent trough centered over NM, with moist
southwest flow streaming across the Gulf Coast ahead of it.
Although local radars were indicating some low returns over
portions of our forecast area, so far this precipitation was too
light to overcome the dry zones in between cloud layers. This is
likely to continue until this evening. Despite ample clouds, highs
today will be a little above average- in the mid 60s around Dothan
and Albany to lower 70s around Tallahassee and Cross City.
[Through 12Z Friday] VFR cigs will lower to MVFR levels overnight
as steady rain develops across the region. Occasional heavy rain
and IFR cigs are possible by daybreak Friday.
.Prev Discussion [429 AM EST]...
.Short Term [Tonight Through Saturday]...
A vigorous upper level trough will aid in the development of a
surface low west of the area tonight that will move across the
area on Friday, bringing the threat of heavy rainfall and maybe a
Confidence is fairly high that a widespread 1.5-3" rainfall will
occur with locally higher amounts. Precipitable water values are
expected to rise to around the 99th percentile for January, and a
large shield of moderate to heavy rain is likely north of the warm
front, which will be situated near the coast. In addition, with
the unseasonably high atmospheric moisture content, thunderstorms
will be efficient rainfall producers. Most of the guidance members
(both global and locally run CAMs) are in decent agreement on the
large scale rainfall amounts.
The threat of severe storms is much less certain. Currently, the
SPC day 2 outlook calls for a marginal risk of severe storms, and
this looks reasonable. This is a very typical cool season low
CAPE/high shear scenario for our area. If the warm front can lift
northward away from the coast, then the threat of severe weather
would increase across the area with more instability. However, it
is not certain whether or not that will occur. Many times the warm
front stays pinned near the coast with the severe threat limited
to just the coastal areas. However, this is a fairly dynamic
system and shear values will be high, so mesoscale trends will
have to be monitored closely on Friday as there could be threat of
damaging winds or an isolated tornado or two if enough instability
can penetrate inland.
This system will begin to exit the area on Friday night with a
return to dry conditions on Saturday.
.Long Term [Saturday Night Through Thursday]...
After the wet system on Friday, upper level northwest flow with a
lack of moisture is expected to allow for dry conditions.
Temperatures are expected to be seasonal.
Winds and seas are expected to increase to advisory levels
starting this afternoon west of Apalachicola and tonight across
the remainder of the area ahead of a strong frontal system. A few
gusts could reach gale force late tonight through Friday
afternoon. Advisory conditions will continue through Saturday in
the wake of the front, though gusts should fall back below gale
levels. A brief improvement in conditions is expected for Saturday
night and Sunday before a dry cold frontal passage increases the
winds and seas again for early next week.
At this time we are not expecting any fire weather concerns at
least through the weekend.
The upcoming system for tonight and Friday is likely to produce a
large area of 1.5-3" of rainfall with locally higher amounts. This
will cause rivers across the area to rise, but most will likely
remain below flood stage. Currently, the most vulnerable areas to
minor flooding appear to be the Kinchafoonee near Dawson and the
upper Withlacoochee near Valdosta. Ensemble forecasts show the
potential for these sites to rise to minor flood stage. The highest
rainfall is currently forecast along the Ochlockonee, so sites there
may also be more vulnerable to minor flooding.
.Preliminary Point Temps/PoPs...
Tallahassee 70 57 65 52 59 / 0 80 100 50 10
Panama City 67 59 66 50 56 / 10 80 100 40 10
Dothan 65 52 57 45 54 / 10 100 100 40 10
Albany 65 52 57 48 55 / 0 100 100 50 10
Valdosta 69 56 65 54 58 / 0 80 100 70 20
Cross City 72 58 68 58 61 / 10 50 80 80 20
Apalachicola 66 61 67 53 59 / 10 70 100 40 10
GM...Small Craft Advisory from Midnight tonight to 7 PM EST Saturday
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-Waters from Suwannee
River to Apalachicola FL from 20 to 60 NM.
Small Craft Advisory until 7 PM EST Saturday for Coastal waters
from Apalachicola to Destin FL out 20 NM-Waters from
Apalachicola to Destin FL from 20 to 60 NM.