Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
343 PM EST Monday Dec 22 2014
Short term (tonight - tuesday)...
upper level troughing over the Great Plains and weak ridging over
the Caribbean and western Atlantic will rapidly amplify but
otherwise hold in place through the short term period. The warm
front that has kept conditions unsettled over the northern half of
the Florida Peninsula is lifting north out of the area...with
chances of showers and a few storms mostly confined to the Nature
Coast through tonight. Dew points across the area have increased to
around 70...which will encourage sea fog development as southerly
winds move over the cooler shelf waters along the coast beginning
late this afternoon and continuing tonight and Tuesday. Winds remain
generally offshore through the short term period...so would not
expect the dense sea fog to move inland. However...patchy fog and
low stratus will be possible over land overnight tonight and into
early Tuesday morning...though higher clouds will be a limiting
factor in how widespread or dense the fog can get. As
such...expect better fog chances over southwest Florida where cloud
cover will be less.
By Tuesday afternoon...the surface low will be moving into the
Mississippi Delta with upper level diffluence and a weak vorticity
maximum over the northern Florida Peninsula. In response...rain chances
and thunder will increase again over the Nature Coast...but rain
coverage over the central and southern portions of the forecast area
will remain minimal. From the Interstate 4 corridor south...expect
another warm and humid afternoon with high temperatures reaching the
low to middle 80s.
Middle/long term (tuesday night - monday)...
models remain in reasonable agreement as far as the synoptic
pattern...but issues continue in the details of timing and location
of features. For this forecast have generally followed the GFS/European model (ecmwf)
solution which bring the surface cold front into and through the
region late Wednesday afternoon and early Wednesday night with
numerous showers and a few thunderstorms preceding it during
Wednesday and then followed by a few showers into Wednesday night.
NAM continues to be the slowest of the models and about 6 hours
behind the others.
For Tuesday night we are still looking for sea fog to be over the
coastal waters...but the majority of it should remain off the coast
as low level winds will be from the south southeast with the only
exception being Levy County where winds would be onshore some. Over
land some low clouds and patchy fog are expected to develop again
late Tuesday night into Wednesday morning in the warm and humid
airmass in place. Scattered to numerous showers and a few
thunderstorms should be moving into the region from the west and
northwest overnight Tuesday night with rain chances ranging from 20
percent far south to about 90 percent far north.
On Wednesday the sea fog could move onshore during the day as winds
turn more south to southwest with numerous showers and a few
thunderstorms moving across the region. Potential for a few strong
to possibly severe storms still exist with highest probabilities
across the Nature Coast and adjacent coastal waters. Temperatures
will remain warm with highs in the middle 70s to lower 80s away from
the coast. Near the Gulf Coast temperatures could be stuck in the
60s if there is sea fog along with the winds becoming more onshore.
Wednesday night the winds will turn northwest with cooler drier air
overspreading the forecast area. Majority of the convection should
be moving out Wednesday evening with a few lingering showers
possible after midnight.
For Thursday through Friday the cooler drier air will be in place
with mostly clear to partly cloudy skies expected. Over the weekend
models continue to depict varying scenarios as far as another weak
cold front approaching...but either way it should not be that strong
and therefore not much more than some clouds and possibly a few
patchy MVFR ceilings are already moving across the area...and short
range model guidance continues to indicate that this will expand in
coverage overnight. Additionally...fog and low stratus is expected
overnight with periods of IFR or brief LIFR conditions expected.
numerous marine hazards to continue this week. Several rounds of
showers and thunderstorms will continue to move over the
northeastern Gulf waters tonight through midweek ahead of a potent
storm system. Southerly and southwesterly winds will bring a warm
and humid airmass over the cold shelf waters to produce areas of
sea fog tonight and continuing through middle week. Moderate
southerly winds will keep seas in the 3-5 feet range tonight into
Tuesday. Then stronger southwest-west then northwesterly winds
will elevate rough and choppy hazardous seas Wednesday-Thursday into Small
Craft Advisory conditions. High pressure will build into the
region to end the week with winds and seas subsiding by the
no humidity concerns through the rest of the week. Very high surface
dew points will allow for patchy fog to develop each of the next
couple of nights.
Preliminary point temps/pops...
tpa 66 79 68 78 / 30 20 50 80
fmy 66 82 67 82 / 10 10 20 60
gif 65 81 66 81 / 30 20 30 70
srq 66 80 69 80 / 20 10 40 80
bkv 64 80 68 79 / 40 30 60 80
spg 66 77 68 77 / 30 20 50 80
Short term/aviation/fire weather...18/Fleming