Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tallahassee Florida
857 PM EDT Monday may 25 2015
Near term [through tonight]...
Isolated showers and storms will continue through 9 or 10 PM. Once
these storms die out...slight to low end chance probability of precipitation will focus over
the more unstable and humid offshore air mass. Partial becoming
mostly cloudy skies as southeasterly flow pulls Gulf moisture
inland...more humid overnight with minimum temperatures the lower
[through 00z wednesday]...
Convection has waned and traveled west of aby while late day storm
development moving up from the south may briefly impact vld air space
over the next hour. Weakening wind field and partially clearing skies
will set the stage for inland MVFR ceilings/visibilities in shallow
fog...isolated short lived IFR decks around sunrise. High resolution
short term models predict an active breeze day...morning thunder for
terminals closer to the coast with another round of afternoon thunderstorms and rain
anticipated once surface temperatures achieve the upper 80s.
Previous discussion [355 PM edt]...
Short term [tuesday through Wednesday night]...
500 mb heights will fall 20 to 40 meters through Wednesday night
across our forecast area as the 593 dm high off the southeast
coast weakens and translates northeastward toward the Canadian
Maritimes. Our forecast area will become situated under a very
weak trough aloft, with ample deep layer moisture across much of
the region. However, by Wednesday afternoon, the GFS solution
forecasts large scale sinking motion to our east, along the 305
and 310 k surfaces. This will help dry out the lower troposphere,
which is why our pop is lower across our easternmost zones.
Otherwise our pop will be above average- close to 50 percent each
afternoon and evening. The lack of strong winds aloft will work
against storm organization, but lapse rates will likely be
sufficient for a "pulse" severe storm or two.
Long term [thursday through monday]...
The aforementioned descending, drying air from the east will have
its greatest influence on our forecast area this weekend, as the
pop across most of our forecast area returns to at or below climatology
values (20-30 percent each afternoon/evening). Probability of precipitation will return to
early summertime levels by early next week as a weak trough,
accompanied by ample deep layer moisture, becomes established
across much of the southeast. Temperatures will be near climatology
levels, with lows in the 65-70 range and highs around 90. (Of
course, temperatures at the beaches will be moderated by a few
A high pressure ridge will remain centered north and east of the
marine area for the next several days. This will keep east to
southeast winds across the coastal waters, with moderate winds
overnight and in the mornings, and light, mainly onshore winds
during the afternoons.
Minimum afternoon humidities will remain above critical thresholds
(40 to 50 percent). Wetting rains across portions of the forecast
area each day from afternoon sea breeze induced thunderstorm
activity. A shortwave disturbance moving up through the middle
Mississippi River valley Tuesday...along with a tighter lower level
easterly pressure gradient between the middle Atlantic high and eastern
plains lower pressure...will strengthen near term onshore transport.
Transport to weaken and veer west overnight. Weak early morning near
low level inversion will mix out by 9 or 10 am local time...afternoon
mixing depths to achieve 5 to 7 k feet. Highest afternoon dispersion will
generally be over the more eastern counties of southern Georgia and the
Between the daily seabreeze fronts and enhanced upper level forcing,
chances for rain will remain fairly high through Thursday. The
highest rainfall totals will be west of the Alabama-Georgia line/the
Apalachicola River, with widespread totals around 1.5-2". East of
this border, rainfall totals will be around 0.5-1". With area rivers
generally at normal or low levels, no widespread flooding is
forecast to develop from these rainfall totals.
Preliminary point temps/pops...
Tallahassee 72 89 71 89 70 / 10 40 20 40 20
Panama City 74 84 73 84 72 / 20 40 10 40 20
Dothan 70 87 69 88 68 / 30 70 20 50 30
Albany 70 90 70 88 67 / 30 50 30 50 30
Valdosta 70 90 69 90 66 / 20 50 50 30 20
Cross City 72 91 69 91 66 / 20 40 50 20 10
Apalachicola 76 85 74 86 72 / 20 30 20 30 20
Florida...high rip current risk until 5 am EDT /4 am CDT/ Tuesday for
coastal Bay-coastal Franklin-south Walton.