Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
435 am EDT sun Aug 30 2015
Short term (today-monday)...
looking rather wet during the short term period as deep tropical
moisture...precipitable water greater than 2 inches...associated
with the remnants of Erika will spread across the region while the
upper level cutoff low over the deep south lifts northeast. The
upper level diffluence associated with the low combined with the
deep moisture will lead to widespread showers and thunderstorms
this afternoon into this evening. Tonight into Monday the trough
associated with the remnants of Erika will drift a little further
west away from the West Coast of Florida with the flow turning
more southerly. During tonight the convection should wind down
and redevelop out over the Gulf. The flow will gradually turn to
a more southerly direction overnight south of Tampa Bay and some
of these showers and storms could move onshore affecting these
areas late tonight. Then during Monday a more southerly flow will
overspread the entire region and with abundant moisture in place
we should see more numerous showers and storms develop once again.
Although some uncertainty remains with respect to how much rain
will occur over the next couple of days it looks like in general
we will see 2 to 4 inches across the region with some locally
higher amounts...especially near the coast south of Tampa Bay
where the flow will shift to southerly first. Therefore...will
leave Flood Watch as is at this time...but may need to add the
northern counties to the watch with later forecasts as the flow
will eventually become southerly here Monday night into Tuesday.
Middle/long term (monday night-saturday)...
at the start of the long term period...the GFS and European model (ecmwf) are in
good agreement that the remnants of Erika will be a weak open wave
over the eastern Gulf of Mexico that will gradually meander north
and out of the region through Wednesday. As it passes through the
coastal waters...although winds are not expected to be a
concern...the remnants of Erika will bring exceptionally deep
tropical moisture...with model precipitable water values forecast to be as high
as 2.25-2.40 inches through Wednesday. This will favor numerous
showers and thunderstorms with periods of heavy rain that could
cause areal flooding and exacerbate existing river flooding.
During the later half of the week...broad upper level ridging over
the southeastern/south-central Continental U.S. Will be marked by an upper
level closed low over the Mississippi Delta area...while weak
surface high pressure ridges into the Florida Peninsula. Some deep
tropical moisture will remain over the area...generally between 1.8
to 2.25 inches of precipitable water...but overall the pattern will return to a
more typical Summer pattern. Light flow will give way to afternoon
sea breezes with scattered to numerous showers and storms...mainly
during the afternoon and early evening.
some MVFR/local IFR conditions will be possible late this morning
through this evening in showers and thunderstorms. Otherwise...VFR
conditions should prevail.
easterly winds will shift to southeast to south Monday into
Tuesday as the remnants of Erika move northward across the waters.
Then during the second half of the week a weak pressure gradient
will setup rather light and variable winds allowing a decent sea
breeze to develop each afternoon. In general winds will remain 15
knots or less and seas 3 feet or less. However...winds and seas
could be higher in the vicinity of any thunderstorms.
no fire weather concerns over the next few days as a moist
tropical air mass remains across the area.
with two days left in August and the potential for heavy rainfall
Tampa should move up from the current 3rd wettest August...2nd
wettest July/August combined...and tied for 5th wettest Summer
(june/July/august) since record began in 1890.
Tampa area Tampa area Tampa area
wettest August wettest Jul/Aug wettest Summer
1 18.59 in 1949 1 28.31 in 1960 1 43.03 in 1945
2 17.83 in 1898 2 27.48 in 2015* 2 36.13 in 2012
3 15.64 in 2015* 3 26.33 in 1925 3 34.79 in 1909
4 15.17 in 1932 4 26.12 in 1898 4 34.67 in 1960
5 14.90 in 2003 5 24.53 in 1906 5 33.71 in 2015*
33.71 in 1925
* 2015 rainfall total through August 29
Preliminary point temps/pops...
tpa 88 76 88 77 / 90 60 80 60
fmy 88 75 89 76 / 90 60 80 60
gif 89 74 88 74 / 90 60 80 50
srq 89 75 88 77 / 90 60 80 70
bkv 89 73 88 74 / 90 60 80 50
spg 88 77 88 79 / 90 60 80 60
Florida...Flood Watch from 8 am EDT this morning through Monday
evening for coastal Charlotte-coastal Hernando-
coastal Hillsborough-coastal Lee-coastal Manatee-
coastal Pasco-coastal Sarasota-DeSoto-Hardee-
Highlands-inland Charlotte-inland Hernando-inland
Hillsborough-inland Lee-inland Manatee-inland Pasco-
Short term/aviation/marine/fire weather/climate...69/close
long term/decision support...18/Fleming