River Flood Warning 11, NWS Tampa Bay, FL

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
306 PM EDT TUE JUN 7 2016

..More Heavy Rainfall Possible Late Tonight And Wednesday...

.SHORT TERM (Tonight - Wednesday)...
The low level confluence zone and heaviest rain band along it has
shifted southeast this afternoon and now just a broken band of
showers run from about Venice northeast to central Polk County
with other showers noted over the Gulf as well as over Charlotte
and Lee counties. As the afternoon continues expect to see
scattered showers with some locally heavy rains likely to fall
across southwest Florida through early this evening. Across the
remainder of the region abundant tropical moisture (PW's 2+
inches) combined with the presence of a surface trough across the
central peninsula will continue to support some showers with some
brief heavy downpours possible.

Tonight we should see begin to see a decrease in rain chances with
lower pops expected for at least the first part of the night as
overall low level convergence and upper divergence weakens across
the forecast. This however will be short-lived as Hi-res model
guidance shows rain chances increasing again late tonight into
Wednesday morning as another low level convergence zone and
increasing upper divergence sets up across the south-central
forecast area in the vicinity of the surface trough. Similar to
this morning pin pointing exactly where this zone will set up will
be tricky, but most guidance available suggests highlighting
highest pops along and southeast of a line from Venice to Winter
Haven where likely category pops (60-70 percent) will be
advertised with lower pops as one moves further north and west.

Similar to this morning the training of cells will be possible
along this confluence zone, so will add mention of locally heavy
rains into the grids/zones for these areas along with the
possibility of localized flooding. On Wednesday abundant moisture
(PW's aoa 2 inches) combined with a lingering trough axis across
the south-central peninsula will support additional showers and
isolated storms over the region during the day, with some
additional locally heavy rain and highest pops setting up across
central and southern zones where the deepest moisture and best
lift will reside. With the ground extremely saturated from
yesterdays and todays heavy rainfall, any additional heavy rain
will cause rapid run off and flooding and will exacerbate any
ongoing flooding. Given this will extend the Flood Watch from
Pinellas/Hillsborough/Polk counties south through Wednesday
evening.

Temperatures will run slightly above normal through the period
with overnight lows tonight in the mid and upper 70s, with
daytime highs on Wednesday climbing into the upper 80s to around
90 along the coast, and lower to mid 90s inland.

.LONG TERM (Wednesday Night - Tuesday)...
Wednesday evening, a lingering surface trough axis will remain
across southern Florida, with ample moisture holding across most
of the forecast area leading to cloudy skies and scattered
showers and thunderstorms. On Thursday, there is some disagreement
in the model guidance, with the GFS showing a surface low lifting
out of the western Caribbean and moving into western Florida,
while the ECMWF shows a much weaker pattern, and the NAM takes the
surface low northwest and away from the area. At this time, the
most reliable solution seems to be close to the ECMWF, with a weak
surface trough moving northeast across the Gulf and into Florida
on Thursday, keeping the atmospheric column moisture elevated.
Cloudy skies should continue through Thursday afternoon with
numerous showers and thunderstorms, keeping afternoon high
temperatures a few degrees below normal.

Friday and Saturday, weak high pressure is forecast to settle in
over the southeastern CONUS at the surface and aloft, bringing
about a return to a more typical summer pattern. Light surface
winds will allow a well defined sea breeze circulation to form,
along with scattered afternoon thunderstorms. By Sunday, a strong
mid level trough will dig out of Canada and cross the northeastern
US, allowing somewhat drier air to filter into Florida, which
will partially suppress storm coverage in comparison to the rest
of the days during the period. Moisture will return for Monday and
Tuesday as the tail end of the surface trough sags south into the
forecast area, with scattered to numerous showers and
thunderstorms, mostly during the afternoons and early evenings.

&&

.AVIATION...
Brief MVFR/IFR cigs/vsbys will be possible at all terminal sites
through 00Z as scattered to numerous showers and isolated storms
continue across the region. Outside of the convection VFR will
prevail. Additional MVFR/IFR conditions will be possible after 06Z
tonight through the end of the Taf period as shra/tsra re-
develop over the region, with best chances for these conditions at
KFMY, KRSW, KPGD, and KSRQ terminals.

&&

.MARINE...
A trough of low pressure will remain across the Gulf waters and
central Florida peninsula through Wednesday. This trough will keep
a southwest wind flow in place from Venice south to Bonita Beach
while the current northwest flow across the northern waters
becomes light north to northeast with an onshore component
developing along the coast during Wednesday afternoon. During
Thursday through the upcoming weekend the forecast gets a bit
complicated as some of the models want to develop and bring a weak
low pressure area or trough northeastward from the Yucatan Channel
area. There is a lot of uncertainty as to how this feature will
affect the region if at all at this point in time, so will keep
winds and seas below 15 knots and 5 feet for now through the
period, and wait to see if better continuity develops among the
models in the next day or so. In the interim wind and seas
continue to slowly diminish and subside this afternoon...so should
be able to allow the small craft and high surf advisories and the
high rip current risk all expire at 4 PM.

&&

.FIRE WEATHER...
Ample moisture along with daily rain chances will keep humidity
values well above critical levels through the remainder of the
week with no fire weather issues expected.

&&

.Preliminary Point Temps/PoPs...
TPA  77  89  77  87 /  20  40  40  60
FMY  77  84  76  87 /  50  70  50  50
GIF  75  88  75  87 /  30  70  30  60
SRQ  77  85  77  86 /  40  50  50  50
BKV  74  89  74  88 /  20  40  30  60
SPG  77  86  78  87 /  20  40  50  60

&&

.TBW Watches/Warnings/Advisories...
FL...High Rip Current Risk until 4 PM EDT this afternoon for
     Coastal Charlotte-Coastal Hillsborough-Coastal Lee-
     Coastal Manatee-Coastal Sarasota-Pinellas.

     Flood Watch through Wednesday evening for Coastal
     Charlotte-Coastal Hillsborough-Coastal Lee-Coastal
     Manatee-Coastal Sarasota-DeSoto-Hardee-Highlands-
     Inland Charlotte-Inland Hillsborough-Inland Lee-
     Inland Manatee-Inland Sarasota-Pinellas-Polk.

     High Surf Advisory until 4 PM EDT this afternoon for
     Coastal Charlotte-Coastal Hillsborough-Coastal Lee-
     Coastal Manatee-Coastal Sarasota-Pinellas.

Gulf waters...Small Craft Advisory until 4 PM EDT this afternoon for
     Charlotte Harbor and Pine Island Sound-Coastal waters
     from Bonita Beach to Englewood FL out 20 NM-Coastal
     waters from Englewood to Tarpon Springs FL out 20 NM-
     Coastal waters from Tarpon Springs to Suwannee River
     FL out 20 NM-Tampa Bay waters-Waters from Bonita
     Beach to Englewood FL out 20 to 60 NM-Waters from
     Englewood to Tarpon Springs FL out 20 to 60 NM-Waters
     from Tarpon Springs to Suwannee River FL out 20 to 60
     NM.

&&

SHORT TERM/AVIATION/MARINE/FIRE WEATHER...57/McMichael
MID TERM/LONG TERM/DECISION SUPPORT...18/Fleming