Scientific Forecaster Discussion
fxus62 ktae 290023
Area forecast discussion
National Weather Service Tallahassee Florida
823 PM EDT Wed Jun 28 2017
No major changes planned for the overnight hours. Convection
inland will continue to gradually wane over the next several hours
with the loss of daytime heating. However, a broad shortwave
trough will continue to move into the region overnight, advecting
additional deep tropical moisture into the area, and increasing
rain chances across the western third of the County Warning Area prior to sunrise.
Previous discussion [729 PM edt]...
Near term [through tonight]...
showers and thunderstorms will continue to develop across the
Florida Panhandle and Big Bend through the afternoon before
diminishing after sunset. A weak shortwave aloft will move northeast
into the Panhandle overnight. This will lead to an increase in
showers over the coastal waters and Panhandle coast after midnight.
Short term [thursday through Friday night]...
model guidance continues to be in good agreement in the
development of offshore convection early in the day on Thursday
and then spreading inland across the Florida Panhandle and
perhaps into southeastern Alabama by midday Thursday as an
approaching upper disturbance moves through the region. Still some
differences in the details with respect to afternoon storms. It's
possible that the cloud cover from the morning convection
effectively stabilizes southeastern Alabama and they see little
additional storms through the afternoon. This does not seem to be
the case further east into southwestern Georgia and into the
Florida Big Bend where cloud cover should be more sparse, at least
early in the day. Rain chances are generally in the 60 to 70
percent range across the area. With all the cloud cover,
temperatures will be cooler than normal for this time of year,
generally in the low to mid 80s.
Model guidance shows the disturbance moving northeast of the
region by daybreak on Friday with the mid level ridge beginning to
build westward across the Florida Peninsula. This should put our
region in a more typical summertime pattern dominated by the daily
sea breeze circulation. With southwesterly flow around 10 kt,
this should yield fairly decent coverage of showers and
thunderstorms Friday afternoon. Will keep pops a little higher
than climatology, around 60 percent inland. Since convection
should have a later start time, expect temperatures to be a little
warmer, generally in the upper 80s to near 90 degrees.
Long term [saturday through wednesday]...
at the start of the period, ridging will continue building over
the Florida Peninsula on Saturday and then into the eastern Gulf
of Mexico on Sunday. Our region will be on the northern periphery
of this ridge, which will provide some convective suppression
during the afternoon hours. However, both the GFS and Euro do show
weak shortwaves moving through the Tennessee River valley sun-Tue
flattening out the northward extension of the ridge. As a result,
expect thunderstorm coverage each day through Tuesday to be near
normal levels for this time of year, which is about 40 percent.
That being said, there is some potential for a drier stretch if
the Euro verifies, as it shows a significantly drier airmass
across the region than the 28/12z GFS. One additional side effect
of the ridge will be warmer than normal high temperatures sun-
tues, where some of the guidance suggests highs in the mid to
possibly even upper 90s. This would also result in high heat
indices easily in the triple digits.
By Wednesday, the mid level ridge breaks down and an approaching
trough will lead to increasing afternoon/evening rain chances at
the end of the forecast period and slightly cooler afternoon
Aviation [through 00z friday]...
Scattered and showers and thunderstorms continue around the taf
sites this evening but with thunderstorms decreasing, tafs are
limited to showers this evening. While convection will diminish
overnight, expect showers and thunderstorms earlier tomorrow at
ecp with widespread convection pushing north and east through the
day. With a disturbance, will see much more coverage than a
typical Summer day. MVFR cigs are possible tomorrow morning.
winds and seas will remain low through the next several days.
After high rain chances on Thursday and Friday, expect a return to
typical scattered showers and thunderstorms later in the weekend.
red flag conditions are not expected over the next few days with
relative humidity criteria well above critical thresholds. While dispersion
indices will be on the low side, they appear to stay just above 20
across the Florida counties.
all area rivers have crested below flood stage across the region
after last week's rainfall. There is some potential for locally
heavy rainfall across the area on Thursday and into Friday as the
disturbance moves through the region. The primary impact would be
localized flooding limited mainly to urban areas. However, the
overall flood threat remains low.
Preliminary point temps/pops...
Tallahassee 72 85 73 89 74 / 40 60 20 60 20
Panama City 76 83 76 86 77 / 50 80 20 50 10
Dothan 72 82 72 89 73 / 40 60 30 60 30
Albany 72 84 72 90 73 / 30 70 40 60 40
Valdosta 72 86 72 89 73 / 30 70 40 60 30
Cross City 73 89 73 91 74 / 40 50 20 40 20
Apalachicola 77 85 77 87 76 / 40 70 20 40 10