Area Forecast Discussion
Issued by NWS
FXUS62 KTAE 251842
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
242 PM EDT Thu Sep 25 2014
.Near Term [Through Tonight]...
There are no significant upper air features during this time
frame. High pressure at the sfc over northeast CONUS is bringing
northeasterly winds off the Atlantic. There is a stationary
boundary off the east coast of north FL. This setup has enough
moisture and lift for widespread cloud cover especially overnight.
The cool air mass and abundant cloud cover means unseasonably cool
highs for this afternoon in the mid 70s. Lows will be in the mid
.Short Term [Friday Through Saturday Night]...
Expect one more day of relatively cool northeasterly flow on
Friday with the trough of low pressure still along the eastern
seaboard and high pressure nosing down the lee of the
Appalachians. Primary forecast challenge for Friday will be
high temperatures once again. If the sun is able to break out,
temperatures will likely reach the mid to upper 80s. However,
model soundings indicate that the low-level northeastly flow will
be topped by some weak isentropic lift on Friday, which may help
to hold the clouds in through much of the day. Have leaned towards
this scenario and have max temps several degrees below guidance
(and even this could still be a bit warm).
By later in the day, expect to see an increase in showers over the
southeastern Big Bend as an inverted trough crosses the peninsula
towards the west. Deep moisture will continue to increase Friday
night into Saturday as the surface trough moves across the coastal
waters. Expect the best rain chances to be over the water Friday
night, with showers and isolated thunderstorms spreading inland
during the day on Saturday into Saturday night. Locally heavy rain
cannot be ruled out, given the high precipitable waters values.
However, at this time, most of the guidance keeps the heaviest
rain offshore through Saturday night, with totals around 1 inch
along the Panhandle coast and lower amounts inland.
.Long Term [Sunday Through Thursday]...
Deep moisture will be in place for Sunday and Monday as the
inverted surface trough interacts with an upper trough over the
central Gulf Coast. This should result in elevated rain chances
for these two days, with locally heavy rainfall possible given
precipitable water values above 2 inches. Things should begin to
dry out by late Monday or Tuesday as the upper energy shears out
to the northeast. The global guidance differs in the timing on
when the deep moisture moves out, so have left some low end PoPs
in the forecast for much of the forecast period. With the tropical
airmass for the first part of the period and no significant
airmass change expected behind this system, expect temperatures to
run near or just above normal into the middle of next week.
[Through 18Z Friday] MVFR cigs will linger into the afternoon
hours. ECP and DHN will likely scatter out in the next few hours.
TLH might scatter out in the late afternoon hours. MVFR cigs will
return tonight with the possibility of IFR cigs particularily at
VLD. Winds will be light and northeasterly.
Northeasterly flow will continue into Friday night before shifting
to easterly on Saturday and the southeasterly Saturday night into
Sunday. Conditions will likely remain at or near exercise caution
levels through the weekend before winds weaken early next week.
Red flag criteria will not be a concern over the next several
days as moisture levels and rain chances increase. Daytime mixing
heights will be on the low side and this will help to keep
dispersion indices below 30 in most cases both Friday and
The above mentioned period of wet weather (Friday through at least
Sunday) could produce, on average, 1 to 2 inches of rain across
north Florida. Elsewhere, averages on the order of an inch or less
are more likely. These amounts are not expected to result in any
river flooding due to the widespread low flows. Depending on
whether the heavy rain persists through Tuesday, which is
uncertain, there may be some minor river flooding issues.
.Preliminary Point Temps/PoPs...
Tallahassee 64 83 71 85 71 / 10 30 40 60 40
Panama City 67 84 72 84 73 / 0 20 40 60 50
Dothan 63 81 67 83 69 / 0 10 20 50 40
Albany 64 79 68 84 70 / 10 10 30 40 40
Valdosta 66 81 70 86 70 / 10 40 40 50 40
Cross City 69 84 71 86 70 / 10 60 60 60 40
Apalachicola 70 82 74 83 74 / 10 30 50 60 50