Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tallahassee Florida
337 am EDT Monday may 25 2015
Near term [through today]...
Water vapor imagery indicates a persistent upper level low spinning
across the Central High plains near the Nebraska Panhandle. One
primary vorticity lobe extending from this feature is approaching the
Mississippi Valley with another pivoting across New Mexico. At the
surface, a ridge of high pressure remains in place off the middle
Atlantic coast which continues to produce east-southeast low level flow across
the forecast area. Radar shows some isolated showers moving nwwd
across our Gulf coastal waters. To the west, a qlcs is weakening as
it moves eastward across Mississippi. Most hi res models dissipate this
feature before it reaches US. However, remnant outflow boundaries
may act as a trigger for convection across our western zones today.
These areas will also get some contribution to lift from the DPVA
associated with the approaching vorticity lobe. Probability of precipitation will be in the
chance category for most areas today, but increase to likely across
our western zones and even categorical in Coffee and Geneva
counties. Maximum temperatures will be within a couple degrees either side of
90 with the sea breeze holding coastal areas in the lower to middle
Short term [tonight through wednesday]...
The upper-level ridge that has dominated the southeast recently
will be compressed eastward in response to a shortwave moving
through the plains and Mississippi Valley regions. From west to
east, this will gradually place the region under a southwesterly
flow regime aloft. At the surface, we'll remain poised along the
western periphery of high pressure, with continued
east/southeasterly flow. Southwesterly flow aloft and southerly
flow at the surface will moisten the column to slightly higher
than average levels over the next several days. This will combine
with one of our wettest seabreeze regimes to force showers and
thunderstorms along The Big Bend and Panhandle seabreeze fronts on
Tuesday, with an early evening arrival of the Atlantic seabreeze
across the Suwannee Valley. On Wednesday, the aforementioned
shortwave will reach the southeast and provide a little extra
support for shower and thunderstorm development west of the
Apalachicola and Chattahoochee rivers, with more seasonable rain
chances elsewhere. Each afternoon will feature a low threat for
severe thunderstorm development; though with some steeper than
usual lapse rates advecting into the region, an isolated storm
with gusty winds and/or small hail cannot be ruled out. High
temperatures will be in the upper 80s to low 90s, near normal.
Long term [wednesday night through monday]...
Wednesday's upper level wave will be departing the region on
Thursday, but will result in one more day of above average rain
chances. Thereafter, a low-amplitude ridge builds in aloft with
high pressure at the surface. This means near climatological probability of precipitation
in varying afternoon seabreeze regimes. High's will also peak near
[through 06z tuesday]
This set of tafs trends decidedly more pessimistic than the last
set. MVFR ceilings are forecast to develop overnight across the
forecast area. Convection is forecast to be widespread enough this
afternoon to include it as prevailing at dhn and as a temporary
condition at the remaining terminals.
With a prolonged east/southeasterly flow regime, expect nocturnal
surges each night, gradually weakening each afternoon. At this
time, advisory conditions are not expected, though the surges
could reach cautionary levels.
Relative humidity will remain above critical thresholds this week with wetting
rains expected across portions of the forecast area each day.
Dispersion indices will be on the high side today and even higher on
Rain chances will increase through midweek, especially west of the
Apalachicola River. However, expected rainfall amounts are not
expected to have a significant impact on area rivers and streams.
Preliminary point temps/pops...
Tallahassee 91 74 89 73 89 / 30 30 40 20 40
Panama City 84 75 84 73 84 / 50 30 50 30 50
Dothan 88 70 87 68 87 / 60 20 70 30 70
Albany 89 70 89 69 87 / 40 40 60 30 60
Valdosta 91 70 89 69 88 / 50 30 50 40 30
Cross City 92 72 91 68 91 / 40 40 50 40 20
Apalachicola 86 76 86 75 86 / 40 40 50 40 40
Florida...high rip current risk until 4 am EDT /3 am CDT/ early Tuesday
morning for Franklin and Walton County beaches.