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Area forecast discussion 
National Weather Service Tampa Bay Ruskin Florida
304 PM EST Tuesday Nov 25 2014

..widespread heavy rainfall amounts possible through Wednesday...
..A few severe storms possible through tonight...
..hazardous marine conditions developing tonight through Wednesday...

Short term (tonight - wednesday)...
a strong upper level trough will move east across the northern Gulf
the remainder of this afternoon and tonight and across the Northern
Peninsula on Wednesday. As this trough moves eastward it will induce
surface low pressure over the eastern Gulf waters this afternoon with
this low then tracking east-northeast across the north Central
Peninsula tonight deepening as it moves northeastward up along and
just offshore the middle Atlantic coast through early Wednesday. Ahead
of this low a very moist and unstable air mass along with deep
layered effective shear (40 to 50 knot range) will support widespread
showers with embedded storms...some storms possibly severe across
the forecast area the remainder of this afternoon through early
Wednesday.

With strong upper divergence from favorable upper level jet dynamics
over the northern Gulf and enhanced low level convergence from the
developing low and frontal boundary the potential for some widespread
heavy rainfall amounts on the order of 2 to 4 inches with localized
amounts of 5 to 6 inches will be possible through Wednesday morning
as these features affect the region. Given this heavy rain potential
will maintain a Flood Watch for all counties except Charlotte and
Lee through noon on Wednesday.

As for rest of this afternoon expect to see additional showers and
storms fire off across the region within the warm sector with some
strong storms moving in from the Gulf with some locally heavy
rainfall amounts possible. Tonight the surface low will track
quickly to the northeast with a trailing cold front sweeping
southeast through the region. As mentioned above good low level
convergence along and ahead of the front and strong upper level
divergence will support a continuation of widespread rain with
embedded storms across the region with more locally heavy rainfall
possible.

On Wednesday the rain will end in most area by early afternoon as
a much drier and cooler air mass advects into the region on a breezy
northwest wind flow in the wake of the front with gradual clearing
expected across northern and central zones during the afternoon.
Cool air advection and lingering clouds through the first half
of the day will support a much cooler day with maximum temperatures
likely only to rise some 5 to 6 degrees higher than the early
morning min temperatures with highs only reaching the lower to middle
60s north into central zones...and upper 60s far south with the wind
making it feel even cooler.



Long term (wednesday night - tuesday)...
middle-upper level trough will swing offshore of the Atlantic coast
through Thursday. At the surface...high pressure will dominate the
period as high pressure in the wake of tonights front is
reinforced by another high center crossing the MS River Valley on
Thursday. This will promote several days of pleasant cool and dry
weather with below normal temperatures heading into the weekend...but
this pattern will also keep elevated winds and seas across the
marine areas through Friday. Currently looks like winds will be
more in scec range Thursday and Friday although may approach Small Craft Advisory with
secondary surge briefly. Temperatures may approach freezing Friday
morning...but guidance generally shows middle 30s in the Nature Coast
and 40s across southern half at this time. High center will elongate from the
Florida/Georgia border out into the Atlantic with more easterly flow
developing across the region over the weekend. This will lead to
the beginning of the moderation trend which will continue through
early next week. Airmass will be slow to moisten though which
means continue pleasant conditions with near normal temperatures. Next
significant system and rain chance is at least several days beyond
current forecast period.

&&

Aviation...
widespread prevailing MVFR/IFR ceilings and visibilities will impact
the terminals through taf forecast period as an area of low pressure
and cold front affect the region. South to southwest winds in the
12 to 15 knot range with gusts up to 25 knots and higher gusts in
the vicinity of thunderstorms and rain this afternoon and tonight will shift to the
northwest and increase to 15 to 20 knots with gusts up 30 knots
possible after 11z Wednesday morning as the cold front moves through
the region.

&&

Marine...
widespread showers and thunderstorms over the northern and central
Gulf waters will expand in coverage and continue tonight as an area
of low pressure moves into the region from the central Gulf. Locally
hazardous boating conditions will occur in the vicinity of the
stronger thunderstorms. As the low moves in tonight with a
trailing cold front...winds will turn to the northwest and quickly
increase to around 25 to 30 knots sustained with higher gusts...and
seas will build to around 10 feet offshore. This will trigger small
craft advisories spreading north to south through the waters
starting late tonight. Winds and seas will taper off during the day
on Wednesday as high pressure builds in from the west...although
winds offshore will remain in the 15-20 knot range through at least
Thursday evening. With the high dew point air continuing to move
over the cooler Gulf waters...will extend the dense fog advisory
for the central and northern near and offshore waters as well as
the Tampa Bay waters until 10 PM EST tonight. The increasing onshore
flow will help to create high surf and an increased risk for rip
currents along area beaches by early Wednesday morning so will
hoist a high surf advisory and rip current statement from Pinellas
Hillsborough south from 13-21z on Wednesday to account for these
hazardous beach conditions.

&&

Fire weather...
a much drier and cooler air mass will overspread the region on
Wednesday on a breezy northwest wind flow in the wake of a cold
front. Despite the drier air though temperature dew point spreads
should remain low which will keep humidity values above critical
levels. In addition the rain chances will keep erc values low
so no fire weather issues are expected through the end of the
week.

&&

Preliminary point temps/pops...
tpa 58 64 48 68 / 90 70 0 0
fmy 64 68 48 73 / 80 60 0 0
gif 57 65 47 68 / 90 90 0 0
srq 61 66 47 70 / 90 70 0 0
bkv 55 63 36 68 / 90 60 0 0
spg 60 65 54 68 / 90 60 0 0

&&

Tbw watches/warnings/advisories...
Florida...rip current risk from Wednesday morning through Wednesday
afternoon for coastal Charlotte-coastal Hillsborough-
coastal Lee-coastal Manatee-coastal Sarasota-Pinellas.

Flood Watch through Wednesday morning for coastal Citrus-
coastal Hernando-coastal Hillsborough-coastal Levy-
coastal Manatee-coastal Pasco-coastal Sarasota-DeSoto-
Hardee-Highlands-inland Citrus-inland Hernando-inland
Hillsborough-inland Levy-inland Manatee-inland Pasco-
inland Sarasota-Pinellas-Polk-Sumter.

High surf advisory from 8 am to 4 PM EST Wednesday for
coastal Charlotte-coastal Hillsborough-coastal Lee-
coastal Manatee-coastal Sarasota-Pinellas.

Gulf waters...dense fog advisory until 10 PM EST this evening for
Englewood to Tarpon Springs out 20 nm-Englewood to
Tarpon Springs out 20 to 60 nm-Tampa Bay waters-
Tarpon Springs to Suwannee River out 20 nm-Tarpon
Springs to Suwannee River out 20 to 60 nm.

Small Craft Advisory from 11 PM this evening to 1 PM EST
Wednesday for Tarpon Springs to Suwannee River out 20
nm-Tarpon Springs to Suwannee River out 20 to 60 nm.

Small Craft Advisory from 1 am to 4 PM EST Wednesday for
Bonita Beach to Englewood out 20 nm-Bonita Beach to
Englewood out 20 to 60 nm-Charlotte Harbor and Pine
Island Sound-Englewood to Tarpon Springs out 20 nm-
Englewood to Tarpon Springs out 20 to 60 nm-Tampa Bay
waters.

&&

$$

Short term/aviation/fire weather...57/McMichael
long term...88/gittinger
marine...18/Fleming
decision support...88/gittinger

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