NATIONAL WEATHER SERVICE TALLAHASSEE FL
330 PM EST Sat Jan 4 2014
NEAR TERM [Through Tonight]...
Stratus has lingered all day in southeast Alabama and in the
Apalachicola River basin and points west in the Florida Panhandle.
Temperatures have remained quite cool in those areas, so we adjusted the late afternoon temperatures to match more closely to observations.
Stratus is expected to fill in across the area overnight as low-level moisture gradually increases with increasing southeasterly boundary layer flow.
The result should be a fairly mild night compared with last night, with lows mainly in the 40s (some upper 30s possible northwest).
Patchy fog is being indicated by MOS and probabilistic guidance, so it was included in the grids from 06-12z.
At this time we aren`t expecting any widespread dense fog, and we should see more stratus than fog overall.
SHORT TERM [Sunday Through Monday Night]...
Dramatic changes are in store for the region during the short range portion of the forecast.
By Sunday morning, major amplification of the longwave pattern across the CONUS will be underway as the Polar Vortex begins to drop south into the Upper Midwest. This will drive a 1050mb+ surface high southward into the Northern Plains.
Further south, a shortwave round the base of the deepening trough will send low pressure from the Arklatex to the Ohio River Valley by late Sunday, with the trailing arctic front pushing into Alabama.
Ahead of the front, deep layer moisture will be rather limited.
However, with strong low-level forcing along the front and limited
divergence aloft, expect to see a broken band of showers along and
just behind the front.
The best rain chances are expected through the overnight hours on Sunday, ending rapidly from west to east after midnight.
Despite the arctic air pouring in behind the front, all of the precip is expected to end before temperatures fall enough to support anything frozen.
Following the frontal passage, the big story through the early part of the week will be the arctic airmass expected to spread over the region.
Temperatures will fall rapidly Monday morning in the wake of the front, with upper 20s expected in the northwestern third of the area through mid-morning before temperatures rise briefly during the afternoon.
The morning drop below freezing will necessitate a Freeze Watch for this portion of the area.
Wind Chill Advisory will likely be needed eventually as well.
High temperatures for all areas will likely occur just before the
frontal passage during the morning hours (pre-dawn in some areas).
Afternoon temperatures will likely only reach the 30s (outside of
a few 40s in the eastern Big Bend).
It`s not out of the question that some areas of Southwest Georgia and Southeast Alabama may not rise back above freezing during the day on Monday.
Temperatures will drop into the teens for all but immediate coastal areas Monday night, on the strength of very strong cold air advection.
H85 (5,000 ft. altitude) at KTLH temperatures will likely bottom out in the -6 to -9 range during the overnight hours.
Northerly winds will add to the chill, with apparent temperatures reaching single digits by sunrise on Tuesday.
Long Term [Tuesday Through Saturday]...
Surface high pressure will continue building southeastward Tuesday,
continuing cold air advection from a true Arctic airmass.
Despite clear skies, we`ll struggle to get high temperatures in the low 30s to near 40.
With wind gusts of 15-20 MPH it will feel even colder.
Tuesday night will see another hard freeze like Monday night.
As the high pressure pushes off the east coast Wednesday through Thursday, winds will shift to the east and then south and once again return warmer, moist air to the region.
As an upper level disturbance propagates through otherwise mostly zonal flow and develops another mid and upper level trough, another cold front will begin to develop and then move across our area later next week.
Chances for rain increase through the weekend, with widespread chances (30-50%) Friday through Saturday.
Stratus with MVFR CIGS has lingered all day at DHN, with stratus also lingering at ECP (VFR CIGS).
We expect stratus to fill in across the remaining terminals this evening with CIGS at most sites lowering into the MVFR and eventually IFR range with time.
CIGS will gradually improve tomorrow morning, but should remain at least MVFR through 18z.
Winds will remain relatively light over the coastal waters through Sunday afternoon.
Thereafter, conditions will deteriorate rapidly as a strong cold front crosses the region.
Advisory conditions will commence Sunday night with strong northwesterly flow, with winds not dropping below 20 knots until late Tuesday.
Exercise Caution headlines will then likely be needed through
Wednesday before conditions improve.
Monday will be breezy with much drier filtering in behind an Arctic
However, minimum relative humidity values are currently forecast to remain above critical levels.
On Tuesday, although most areas will see max temps only in the 30s, forecast dew points will be around zero to the single digits. This will put relative humidity values in the 20 to 25 percent range.
Red flag conditions are likely to occur.
Only the Apalachicola River at Blountstown and the Choctawhatchee
River near Bruce are in minor flood stage. Bruce is expected to hover near the flood stage threshold for most of today, falling below flood stage overnight.
Blountstown is falling, but is forecast to remain in minor flood stage through Tuesday morning.
Detailed stage information pertaining to the above, and all area
rivers can be found at the following link:
Preliminary Point Temps/PoPs...
Tallahassee 45 68 41 42 19 / 10 20 50 20 0
Panama City 47 67 38 42 22 / 10 20 50 10 0
Dothan 39 65 28 35 16 / 10 20 50 10 0
Albany 41 65 35 37 15 / 10 20 50 10 0
Valdosta 44 67 46 47 19 / 10 20 50 30 10
Cross City 51 73 61 63 20 / 10 20 50 40 10
Apalachicola 50 67 43 44 22 / 10 20 50 20 0
FL...Freeze Watch from late Sunday night through Monday morning for
Central Walton-Holmes-Inland Walton-Jackson-Washington.
GA...Freeze Watch from late Sunday night through Monday morning for
AL...Freeze Watch from late Sunday night through Monday morning for