Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
327 am EDT Monday Aug 3 2015
..Flood Watch remains in effect for Levy...Citrus...Hernando...
Pasco...Pinellas...and Hillsborough counties through late this
..excessive heavy rainfall and flooding possible from the Tampa
Bay area north through the Nature Coast today...
..high risk of rip currents along area beaches today...
..Minor coastal flooding possible at times of high tide today...
Short term (today - tuesday)...
middle and upper level ridging will remain in place over the
southwestern states during the short term period while the
persistent upper level trough over the eastern U.S finally begins
to weaken some and shift east with time with upper ridging over
the Atlantic building west over the peninsula. At the surface a
weak area of low pressure just offshore Levy and Citrus counties
along a stationary frontal trough that is draped across the
southeastern states and into the northern Gulf region will move
slowly east northeast across north-central Florida and southeast
Georgia today and then up along the middle-Atlantic coast tonight and
Tuesday...while surface high pressure across the southern
peninsula drifts slowly north to near Lake Okeechobee on Tuesday.
Deep tropical moisture (pw's in the 2 to 2.4 inch range) will
remain over the forecast area today. This deep moisture combined
with the trough/low and a strong onshore flow (20+ knots) off the
Gulf enhancing low level coastal convergence and lift will support
one more day of numerous showers and scattered storms across the
forecast area...with the continued risk of excessive heavy
rainfall amounts causing additional flooding problems as well as
exacerbating the ongoing flooding from the Tampa Bay area north
through the Nature Coast.
The highly saturated ground across the area combined with the
ongoing flooding problems and the potential for more heavy rain
today warrants keeping the Flood Watch for Pinellas...
Hillsborough...Pasco...Hernando...Citrus...and Levy counties in
effect through late this afternoon. Across the remainder of the
forecast area scattered showers and isolated storms will continue
to be the rule within the very moist and unstable air mass...with
the threat of locally heavy rainfall...gusty winds...and
occasional lightning strikes.
During tonight into Tuesday the persistent upper level trough over
the eastern U.S. Will weaken some and shift east with the
attendant frontal trough to the north gradually washing out on
Tuesday as surface high pressure to the south re-builds in over
the region. As this occurs we should finally see an end to the
very heavy rainfall we have been experiencing of late with a
return to a more typical Summer time pattern of scattered showers
and storms developing along the sea breeze circulations...with the
highest rain chances shifting from coastal areas to interior
sections during the afternoon hours as the sea breeze boundaries
Daytime temperatures today will remain a few degrees below normal
due to cloud cover and high rain chances with highs in the middle
to upper 80s. Daytime highs should return to near normal on
Tuesday as a bit more sun is expected. Overnight lows will remain
above normal along the coast where readings in the upper 70s to
around 80 will continue with lower to middle 70s inland.
Middle/long term (tuesday night - sunday)...
models in good agreement through much of the period with features
in the region. Upper trough holds north of the region while weak
upper ridging builds over the area from the north Caribbean middle to
late week. Surface western Atlantic high pressure stretches across
the central Florida Peninsula and East Gulf of Mexico with a
return to more typical summertime precipitation pattern with diurnal
convection along sea breeze interactions. Warm daytime
temperatures return to around seasonal normals.
For next weekend...models swing another shortwave trough into the
East Coast longwave trough amplifying back sward into the S.E. U.S.
While pushing a surface frontal boundary into the deep south. This
will push the surface ridge axis back over South Florida with a return
to SW flow for much of the region. Latest guidance suggests best
rain chances will be from the Tampa Bay region nward in the deeper
moist SW flow while SW Florida may see more typical afternoon storms.
abundant moisture combined with a trough of low pressure over the
area will continue to support numerous showers and scattered storms
over the region during the next 24 hours. Rain showers/thunderstorms and rain that move over
the terminal sites will produce brief MVFR/IFR conditions...otherwise
VFR will prevail. Southwest winds in the 10 to 14 knot range early
this morning will increase to 15 to 20 knots with higher gusts
after 16z...with gusts up to 35 knots possible in vicinity of thunderstorms and rain.
a weak area of low pressure over the Gulf waters offshore Levy and
Citrus counties early this morning will move slowly east northeast
across the north-Central Peninsula today and across southeast
Georgia tonight and up along the middle Atlantic coast on Tuesday.
This trough/low combined with surface high pressure over the
southern Florida Peninsula will maintain a moderate and gusty
southwest wind flow over the Gulf waters today...with winds in
seas in the small craft range from Tarpon Springs north to the
Suwannee River where the tightest gradient will continue...with
cautionary winds and seas across the remainder of the waters. The
strong onshore flow will favor a high risk of rip currents along
area beaches from Pinellas County south to Lee County today...so
will keep the ongoing rip current statement in place through late
this afternoon. In addition the strong onshore flow will likely
support tides of 1 to 2 feet above astronomical values with some
minor coastal flooding possible at times of high tide early this
morning and again during the afternoon from Pasco County north to
Levy...so will extend the coastal flood statement for these areas
through late afternoon as well.
Surface high pressure to the south will build slowly north to the
Central Peninsula later tonight through the remainder of the
week with a lighter southeast to southwest wind flow (from south
to north) expected across the waters each day...with an enhanced
onshore sea breeze component developing along the coast each
afternoon. Numerous showers and scattered thunderstorms will be
possible today with the best chances over the near and offshore
waters from Englewood north to the Suwannee River...with scattered
showers and storms expected the remainder of the week during the
afternoon and early evening hours as the high lifts northward and
winds back to the southeast and south.
abundant tropical moisture and high rain chances will keep humidity
values well above critical levels the next several days. Moderate
20 foot winds and transport winds will keep dispersion indices
elevated today and Tuesday...otherwise no other fire weather
issues are expected through the remainder of the week.
river flood warnings continue in effect for the Myakka River at
Myakka River State Park...the Little Manatee River at
Wimauma...Cypress Creek at Worthington Gardens...the Anclote River
at Elfers...and the Hillsborough River at Zephyrhills. Additional
heavy rainfall today will keep water levels along these rivers
elevated and in minor flood with the Anclote River at Elfers
expected to rise to major flooding levels by this afternoon.
All rivers will continue to be closely monitored for any
significant rises in waters levels...and updates to the ongoing
river flood warnings will be issued immediately if conditions
warrant. All residents living along rivers or faster flowing
streams should keep alert to any rapid rises in water levels and
be ready to move to higher ground if flooding is observed.
Preliminary point temps/pops...
tpa 86 77 89 77 / 60 30 50 10
fmy 90 75 91 76 / 50 30 50 40
gif 87 75 90 75 / 60 30 50 40
srq 87 76 89 76 / 50 30 40 20
bkv 85 74 89 73 / 70 40 50 20
spg 86 78 89 78 / 60 30 40 10
Florida...Flood Watch through this afternoon for coastal Citrus-
coastal Hernando-coastal Hillsborough-coastal Levy-
coastal Pasco-inland Citrus-inland Hernando-inland
Hillsborough-inland Levy-inland Pasco-Pinellas.
High rip current risk through this afternoon for coastal
Charlotte-coastal Hillsborough-coastal Lee-coastal
Gulf waters...Small Craft Advisory until 11 am EDT this morning for
coastal waters from Englewood to Tarpon Springs Florida
out 20 nm-Tampa Bay waters-waters from Englewood to
Tarpon Springs Florida out 20 to 60 nm.
Small Craft Advisory until 4 PM EDT this afternoon for
coastal waters from Tarpon Springs to Suwannee River
Florida out 20 nm-waters from Tarpon Springs to Suwannee
River Florida out 20 to 60 nm.
Short term/aviation/marine/fire weather/hydrology...57/McMichael
long term/decision support...25/Davis