Scientific Forecaster Discussion
fxus62 ktbw 170736
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
336 am EDT Tue Oct 17 2017
Short term (today and wednesday)...
the upper pattern across the Continental U.S. Is defined by broad
upper ridging over the eastern Pacific into the southwest
U.S. And broad upper troughing from the northern plains
southward into the eastern Gulf of Mexico. Within this
trough, a substantial shortwave trough has moved off the mid
Atlantic and New England coasts. A trailing cold front
continues to decelerate this morning, extending from the
northern Gulf of Mexico into the Florida Big Bend and
southern Georgia. This feature, and a building surface high
will be the dominant weather features through tomorrow.
As the shortwave trough departs, the energy driving the
cold front south and east will depart, forcing it to stall
later today over far northern Florida. Areas north of the
front will get a fresh taste of Fall weather with much drier
and cooler air settling in. Over much of the Florida
Peninsula, we will see slightly cooler temperatures due to
abundant cloud cover, but we will have to wait a bit longer
for a true taste of fall, as muggy conditions will prevail.
A smattering of showers mixed with the occasional storm will
drift from northeast to southwest across the peninsula
today with the greater chances for rain over interior and
eastern parts of the peninsula.
Expect mainly dry conditions overnight tonight. As slightly
drier air spills in from the north, lows will be a bit
cooler than the last few nights, ranging from the lower to
mid 60s north along the Nature Coast, to the lower to mid
High pressure will continue to build over the southeast
U.S. Tonight into early Wednesday, with prevailing
east/northeast flow. This will bring episodes of heavy
rainfall to the Florida Atlantic coast, but as moisture is
gradually squeezed out from east to west, lesser chances for
rain will reside over interior and western portions of the
peninsula. Still, a chance of a few showers will exist, with
the greater potential remaining over interior/middle/spinal
parts of the peninsula. High temperatures will begin to
rebound tomorrow with highs reaching the middle and upper
Long term (wednesday night through monday)...
Wednesday night and Thursday, a week mid level trough over
Florida will gradually shift east as an amplified ridge
builds into the Gulf of Mexico and deep south. A weak
frontal boundary associated with this trough will be stalled
out across the northern portion of the Florida Peninsula,
with a dry air mass filling in to the north of the boundary.
This will keep rain chances limited over the Nature Coast
Thursday, but modest moisture south of the boundary will
still allow for isolated to scattered showers and
thunderstorms from around Tampa Bay south.
Friday and Saturday, the ridging aloft will shift east and
move over Florida, bringing subsidence and drier air into
the region, limiting rain chances even further. Friday in
particular looks to be the driest day during the period,
with only 10 to 20 percent rain coverage forecast. By
Sunday, the mid level ridge will have moved east of Florida
as an amplified trough crosses the Mississippi River valley,
with a strong surface ridge setting up off the coast of New
England. This will allow the low level flow to turn to
southwesterly, bringing a quick return of moisture to the
area. As a result, more scattered showers and thunderstorms
are forecast for Sunday and Monday.
Temperatures will remain near to a few degrees above
normal, with highs in the 80s and lows generally from the
mid 60s to low 70s
Aviation (06z tafs)...
a remnant front will stall north of terminals. A cluster of
showers and storms in progress over northeast Florida will
build southward overnight, with possible impacts to klal,
where vcsh is maintained. Broken VFR cigs to prevail
overnight, thought patchy MVFR cigs and vsbys due to fog may
occur most anywhere. Light and variable winds will become
northeasterly by sunrise. Scattered showers will move from
northeast to southwest across the region.
cautionary to borderlined advisory winds will persist over
the northern waters today. As high pressure intensifies
north of the waters today and tonight, cautionary to
advisory level winds are forecast to spread southward to
include most of the coastal waters. Breezy northeast winds
coupled with building seas will likely generate hazardous
boating conditions, especially over the offshore waters
tonight into early Wednesday morning. While winds may
slacken somewhat during the day Wednesday, easterly wind
surges will likely result in periods of cautionary to
advisory level winds each night and early morning through
the latter half of the week. Over the weekend, winds may
improve a bit as high pressure finally slips eastward,
resulting in a relaxed gradient over the waters.
a cold front will stall north of the region today, bringing
waves of showers and occasional thunderstorms. High
pressure building in north of the region will result in
northeast winds much of this week. This will allow Atlantic
moisture to stream across the peninsula with daily chances
for showers. As moisture will remain high, and relatively
humidities will remain above critical levels, no fire
weather concerns are expected.
Preliminary point temps/pops...
tpa 82 70 85 71 / 30 10 30 10
fmy 85 72 86 71 / 40 30 40 10
gif 82 70 83 69 / 50 30 40 10
srq 84 72 86 71 / 20 10 30 10
bkv 80 68 84 68 / 20 10 30 10
spg 81 71 83 72 / 30 10 30 10