Rip Currents in Florida, July 20, 2013

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
312 PM EDT Sat Jul 20 2013

.NEAR TERM [Through Tonight]...
Morning and early afternoon convective activity has largely moved
off to the far eastern portion of our forecast area with rain
continuing between Valdosta and Cross City. Where breaks in the
overcast have occurred further to the west, scattered showers are
once again breaking out and lifting northward across the Florida
Panhandle and Southeast Alabama. Expect this to continue for the
next few hours until instability of the day is lost at sunset.

Model guidance is still in good agreement that after a brief lull
this evening, convection should fire once again over the marine
area and move toward the coast. The best chance of rain overnight
appears to be across the Florida Panhandle and perhaps as far
inland as Southeast Alabama.

The flood threat appears to have decreased as storms today
continue to have enough forward motion to prevent any significant
flood issues.

&&

.SHORT TERM [Sunday through Monday]...
The weak surface trough over our forecast area today will likely be
to our north by Sunday, as the subtropical deep layer ridge builds
westward across much of the Gulf of Mexico. Although there will be
little if any Q-G forcing with this ridge building to our south, the
airmass will remain plenty moist with deep layer west-southwest
winds over our area. This is typically a favorable pattern for
numerous showers and thunderstorms, provided that there are
favorable thermodynamics (which there will be). The various NWP
guidance is in good agreement in forecasting plenty of deep moist
convection, so our forecast PoP is above climatology each day
(50-60%). Despite these high PoPs, there will not be enough large
scale forcing to focus high QPF in any one area, so any flooding
that occurs (if it occurs) will be localized and limited primarily
to urban areas and locations get heavy rain today. Highs will be
near average- in the lower to mid 90s.

&&

.LONG TERM [Tuesday through next Saturday]...
The GFS and ECMWF continue to agree that a broad longwave trough
will be the dominant large scale weather feature over the
Southeast. During this time there will likely be multiple minor
short waves rotating through the base of the trough, enhancing our
rain chances at times as both models forecast plenty of deep layer
moisture and CAPE. While the MOS PoP consensus is above
climatology, we will forecast a fairly diurnal cycle, with the
greatest PoP during the afternoon & evening hours (even though sometimes
MCS's can affect our area overnight in this type of pattern).
Despite the above-climo PoPs, the MOS consensus high temperatures
are in the lower to mid 90s, which is near climo. It's interesting to
note that the 1000-700mb lapse rates are forecast to be steeper
than normal (6-7 C/km) through much of this period, with the GFS being
the most unstable. While the mid tropospheric winds are not
expected to be very strong, the thermodynamics may be more
supportive of pulse severe storms than what we have seen in recent
days.

&&

.AVIATION [Through 18z Sunday]...
Scattered SHRA continue across the forecast area. Expect
primarily MVFR conditions in SHRA with an occasional IFR conditions
in the heavier showers. After sunset, much of the shower activity
should dissipate with the threat for storms moving offshore.
Guidance once again indicates extensive low cloudiness likely at
ABY/DHN/VLD at IFR levels before sunrise. Nearshore convection
prior to sunrise will likely affect ECP in the predawn hours and
TLH shortly after sunrise.

&&

.MARINE...
Light to occasionally moderate southwest winds will continue through
Monday, with seas generally in the 2 to 3 feet range.

&&

.FIRE WEATHER...A rainy weather pattern will persist and therefore
red flag conditions are not expected for the forseeable future.

&&

.HYDROLOGY...
Precip Water values will remain above average through at least
Monday. However, limited large scale forcing should prevent a focus
for heavy rain, which is often an ingredient for significant,
widespread flooding. Through Monday evening the global models are
only forecasting 1 to 2 inches of rain, but isolated amounts will be
much higher than this. We have already seen isolated pocket of
rainfall amounts in the 3-6 inch range since Friday afternoon, and
these types of localized amounts could continue through the
remainder of today. The probability of this occurring is low so we
have cancelled the earlier Flash Flood Watch.

Riverwise, the Choctawhatchee River at Bruce was in minor flood
stage and falling. Heavy rains last night and today have occurred in
the lower portions of some of the river basins in the FL Big Bend,
which will cause some sharp rises. For instance we now expect the
Aucilla River at Lamont to reach flood stage.

&&

.PRELIMINARY POINT TEMPS/POPS...
Tallahassee   73  90  73  91  74 / 40  60  30  50  40
Panama City   76  88  76  88  76 / 60  50  30  50  30
Dothan        73  89  73  89  73 / 40  60  30  60  40
Albany        73  90  73  90  73 / 40  60  30  50  30
Valdosta      72  90  72  92  72 / 40  60  30  50  30
Cross City    73  88  73  90  73 / 40  60  30  40  20
Apalachicola  76  87  77  87  77 / 60  60  30  40  30

&&

.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.

&&

NEAR TERM...Godsey
SHORT TERM...Fournier
LONG TERM...Fournier
AVIATION...Godsey
MARINE...Fournier
FIRE WEATHER...Godsey
HYDROLOGY...Fournier