Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 280104
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
904 PM EDT Sun Jul 27 2014
.Near Term [Through Tonight]...
Current fcst is well on track as the meager convection today has
come to an early end this evening. The only significant change to
this package is to account for the stronger SW and W winds over
the coastal waters which are now in the cautionary range, so will
add a SCEC headline for the rest of tonight in the marine fcst..
[Through 00Z Tuesday] Skies will clear within the next hour or so
with the exception of some passing high level cloudiness. Coastal
storms may impact ECP around dawn with some peripheral MVFR
ceilings. All terminals will have VCTS by 18z with a high
likelihood of prevailing storms at DHN, ABY, and VLD later in the
afternoon. Some of the storms tomorrow will have a higher than
normal chance of producing damaging winds.
.Prev Discussion [214 PM EDT]...
.Short Term [Monday Through Tuesday Night]...
This period will be characterized by strongly amplifying meridional
flow with a deepening upper trough over the eastern half of the
country and strong ridge across the west. This will push an
unusually strong summer cold front across the forecast area late
Monday through Tuesday. The front will be poised just to our north
across south central AL and GA Monday evening, and will move to a
position from around Albany to Destin after midnight. Tuesday
morning the front will extend from Valdosta to Apalachicola and
will exit the Big Bend area by midday Tuesday. The upper flow is so
amplified the front is likely to make it as far south as Key West by
late in the week.
Ahead of the front, a very hot and humid airmass will be in place,
with temperatures rising into the upper 90s Monday afternoon. With
dewpoints in the mid 70s, we will still see heat indices exceed 105
degrees over a large portion of the area, with values as high as 108
degrees possible in our Florida counties, so another heat advisory
may be needed for Monday afternoon.
As the front approaches southern AL and southern GA tomorrow
afternoon and evening, there will be broken line of strong to severe
thunderstorms moving across the area. Cape values will approach 4000
J/Kg Monday afternoon and evening ahead of the front with nearly
unidirectional deep west-northwest flow aloft and drying at mid
levels. This scenario will result in some damaging straight-line
winds as the main threat. There could be some hail reports due to
very strong updraft values, but with the airmass being so warm it
may be difficult to get large hail at the surface. Expect the threat
of severe storms from early afternoon until around 9pm-10pm.
A much drier airmass will push in behind the front on Tuesday and
Tuesday night, with dewpoints dropping well into the 60s.
Temperatures will be cooler as well, as 500mb heights drop a good 60
meters through this period. Highs will range from the upper 80s
along the northern border, to lower to mid 90s along the coast and
across the Big Bend.
.Long Term [Wednesday Through Sunday]...
The full latitude eastern CONUS trough will continue to amplify
through the period. The front which will move across the area early
in the week will usher in much drier and cooler air through
Thursday, with the possibility of reaching some record morning lows.
The long standing records for this period at Tallahassee are:
July 30 - 67 (1927)
July 31 - 63 (1896)
Aug 1 - 64 (1993)
Expect generally dry and relatively cool conditions for Wednesday
and Thursday with very low PoPs. Thursday and Friday morning lows,
July 31st and Aug 1st, will range from 65-70.
By late Thursday, moisture will begin to increase once again across
the forecast area as another upper disturbance within the main upper
trough moves into the forecast area. For Friday through the weekend
expect a return to scattered showers and thunderstorms each
afternoon and evening. The increased convection for the end of the
week and weekend will keep high temperatures in the 85 to 90 range
across the area.
The pressure gradient between the subtropical ridge to the south and
the approaching cold front to the north will tighten tonight through
Tuesday with westerly winds reaching exercise caution levels at
times. Winds will gradually diminish and become offshore Tuesday
night into Wednesday.
Red flag conditions are not expected for the next couple of days.
Drier conditions will move in on Tuesday and continue through
Thursday. Relative humidity values may approach critical levels on
Wednesday in North Florida.
The Shoal River at Mossy Head has reached bank full stage but
continues to fall. All other area rivers are below bank full stage.
Thunderstorms could bring locally heavy rainfall on Monday but
widespread impacts are not expected.
.Preliminary Point Temps/PoPs...
Tallahassee 78 96 73 95 67 / 10 50 50 20 10
Panama City 80 91 77 91 73 / 10 40 40 20 10
Dothan 76 96 70 91 67 / 10 50 50 10 0
Albany 77 96 70 91 66 / 10 50 50 10 0
Valdosta 77 96 71 93 65 / 10 50 50 20 10
Cross City 78 94 76 93 69 / 10 30 30 40 10
Apalachicola 80 91 77 92 73 / 10 30 30 20 10
FL...High Rip Current Risk until 11 PM CDT this evening for Coastal