Severe Thunderstorm Warning 189, NWS Tallahassee, FL

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE TALLAHASSEE FL
1054 AM EDT Wed Jul 9 2014

.Near Term [Through Today]...
13Z surface analysis shows high pressure over the GOMEX, keeping
west-southwest flow over our forecast area. This flow is helping
return moisture to the area in the wake of our early season cold
front last week. This return of moisture has been slow and our 12Z
sounding had a PWAT of 1.38", which still is about 75% of normal
values. The 1000-700 mb flow is from the west around 10 kts, making
this a borderline type 4-5 seabreeze day. This pattern normally
favors higher rain chances in northern Florida, but with PWATS still
being below normal, we're expecting lower PoPs than we normally see
with this pattern. We're also looking at the potential for higher
PoPs than normal with this pattern in our southeast Alabama counties
due to outflow boundaries moving off of a cold front to our
northwest. If we do get convection from these outflow boundaries, it
will likely be in the late afternoon-early evening.

&&

.Aviation...
[Through 12Z Thursday]...VFR conditions should prevail at the
terminals, but there will be a better chance for afternoon showers
and thunderstorms with the sea breeze today. Have a convective tempo
at TLH and DHN where the best chances for storms should be with
PROB30s elsewhere. ABY is the lone exception where just the VCTS was
allowed to stand for now.

&&

.Prev Discussion [406 AM EDT]...

.Short Term [Tonight Through Friday]...

The remainder of the week will continue to be dominated by an
eastern U.S. trough aloft, with a very weak pressure pattern at
the surface. Both Thursday and Friday, shortwaves diving south
along the western periphery of the trough will cause it to get
pulled further south into the Southeast. Subsequently, through the
period the attendant surface front will creep southward into the
Tri-State region.

While the large-scale pattern is rather simple, the placement and
coverage of storms will be much more challenging. We'll likely see
the same trend from the past few evenings continue as the front
moves south, with a series of MCS' developing and propagating away
from the front each evening and into the overnight hours. So,
while the bulk of the convection from the first MCS should remain
just west of us tonight, it is unclear just how much the
subsequent cirrus canopy and outflow will impact the start to
convection on Thursday along the front. For now, will carry a more
uncertain than normal 50 PoP west of the Apalachicola and
Chattahoochee rivers for the first half of the day. Late in the
day, what can develop of the Big Bend seabreezes will move inland
and clash with any boundary left over from the overnight
convection. Thus, late afternoon and early evening convection will
most likely occur east of a line from Tallahassee to Albany. With
the front still lingering on Friday, expect much of the same with
some sort of late night/early morning MCS develop, followed by
late afternoon disturbed seabreeze/outflow induced convection. The
bottom line is that PoPs will significantly increase towards the
end of the week and will likely be above climo across the entire
region. Afternoon highs will be kept in check with convection and
subsequent cloud shield. Expect low 90s to be common, except
middle to upper 90s on Thursday across the southeast Big Bend and
Suwannee Valley.

.Long Term [Friday Night Through Wednesday]...

Long term guidance suggests that rain chances will be above
climatology for a good portion of the long term as the Eastern
CONUS will be under the influence of a long wave trough and a
return of abundant moisture. With higher chances for rain,
temperatures will be near climatology with isolated warm spots in
areas that miss the rain.

.Marine...

Winds and seas should remain below headline conditions today,
though a fairly robust seabreeze circulation is forecast to
develop late this afternoon. After this afternoon, light winds
and low seas will prevail under a weak surface pressure pattern
for the next several days. Though, there could be periodic
enhancements if large convective clusters move offshore each
morning.

.Fire Weather...

No Red Flag conditions are expected over the next several days and
afternoon relative humidities will be on the rise as rain chances
and soil moisture gradually increase across the Tri-State area.

.Hydrology...

Though rain chances will be much higher than recent to finish the
week, most rivers are holding steady at levels well below flood
stage with several in low flow. The expected rainfall totals over
the next several days should not result in water level rises that
would force any rivers into flood stage.

&&

.Preliminary Point Temps/PoPs...

Tallahassee   93  75  93  72  91 /  50  10  50  20  50
Panama City   90  77  89  75  86 /  30  30  40  30  40
Dothan        94  74  90  72  92 /  40  30  50  30  50
Albany        95  74  90  72  91 /  30  20  50  30  50
Valdosta      96  72  95  70  95 /  40  10  60  30  50
Cross City    92  72  91  70  91 /  30  20  40  20  50
Apalachicola  89  75  88  72  88 /  30  30  40  20  30

&&

.TAE Watches/Warnings/Advisories...

FL...None.
GA...None.
AL...None.
GM...None.

&&

NEAR TERM...MOORE/WESTON
SHORT TERM...HARRIGAN
LONG TERM...MOORE
AVIATION...MOORE/WESTON
MARINE...HARRIGAN
FIRE WEATHER...GOULD
HYDROLOGY...HARRIGAN