Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
355 am EST sun Jan 25 2015
Short term (today - monday)...
a frontal boundary clears into the Caribbean this morning...with
drier and colder air moving into the peninsula of Florida in its
wake. Aloft...a 500 mb trough will dig into the Tennessee and Ohio
River valleys as it pushes east towards the mid-Atlantic. With a
surface low developing over the southeast United States...guidance
is resolving a frontal boundary moving across the area tonight
into Monday. MOS guidance is aggressively raising rain chances for
this period...in conjunction with the passage of the reinforcing
Examining time-height cross-sections...the moisture seems to be
isolated to the surface and lack much vertical depth. Of
course...the moisture is accompanied by a very healthy upper level
jet. The forecast challenge is whether the dynamical support aloft
will be able to squeeze out rain from the amount of available
moisture since return flow will not be around very long before the
front passes. Currently...trending higher probability of precipitation from Tampa Bay
northward but tempering rain chances compared to some
guidance...particularly in southwest Florida. Temperatures should
remain fairly cool...with the reinforcing air mass and gusty winds
over much of the area.
Long term (monday night - saturday)...
similar to last night at this time an amplified progressive split
flow upper air pattern will persist across the Continental U.S. During the long
term period featuring a large upper ridge out west with a closed low
meandering off Baja California California and a deep cold upper trough covering much of
the central and eastern U.S.. models remain in good agreement with
synoptic scale features this morning so a blend will again be used.
At the start of the period a cold front will be exiting to the south
of the state as a sharp negatively tilted upper trough and attendant
deepening surface low moves up the East Coast. Cool air advection in
the wake of the front will result in a chilly night with overnight
lows falling into the upper 30s across the Nature Coast...lower to
middle 40s central interior zones...and upper 40s to around 50 south
and along the coast. On Tuesday a dry northwest flow aloft combined
with weak high pressure will support cool dry conditions across
the entire forecast area with ample sunshine expected.
During Tuesday night into early Wednesday another reinforcing cold
front will move south through the region as short wave energy moves
through the base of the a deep upper trough along the East Coast.
Lack of moisture accompanying this front will result in a dry
frontal passage with just another shot of cool dry air overspreading
the region on a breezy northwest to northerly wind flow in the wake
of the front.
On Wednesday a dry northwest flow aloft and surface high pressure
building in over the eastern Seaboard will support ample sunshine
and cool dry weather across the forecast area. The high will shift
east into the western Atlantic on Thursday as another amplifying
upper trough and attendant deepening surface low moves from the
upper Mississippi Valley southeastward across the Ohio Valley during
the day...then offshore the northern middle Atlantic coast south of New
England by early Friday morning. As this storm system moves east
another trailing cold front will move east across the lower MS
valley and into the southeastern states and western Florida
Panhandle by Thursday evening...then south through the forecast area
on Friday. Similar to the other fronts lack of sufficient moisture
should preclude rain chances with its passage with just a wind shift
into the northwest and north expected in its wake. Surface high
pressure building in from the northwest in the wake of the front
will provide pleasant dry weather for the start of the upcoming
weekend. Temperatures will run some 5 to 8 degrees below normal
through Thursday before modifying back to near normal Friday and
into the upcoming weekend.
mainly VFR through the period...though some localized low ceilings and
ground fog could affect fog-prone terminals like lal early this
light winds this morning will shift to a more southwest to
westerly direction this afternoon as the next cold front
approaches the waters. The front will sweep across the coastal
waters late tonight into Monday morning followed by another
period of advisory criteria winds and seas through Tuesday morning.
High pressure will then settle over the waters for the middle of
no immediate fire weather concerns are expected as the weekend
concludes and work week begins.
Preliminary point temps/pops...
tpa 64 53 64 48 / 0 50 50 0
fmy 68 55 69 50 / 0 10 50 0
gif 66 50 66 44 / 0 30 50 0
srq 65 56 66 50 / 0 40 50 0
bkv 65 45 62 39 / 0 50 40 0
spg 64 55 64 52 / 0 50 50 0
Gulf waters...Small Craft Advisory from 1 am Monday to 10 am EST Tuesday
for Bonita Beach to Englewood out 20 to 60 nm-
Englewood to Tarpon Springs out 20 to 60 nm-Tarpon
Springs to Suwannee River out 20 to 60 nm.
Small Craft Advisory from 4 am Monday to 7 am EST Tuesday
for Bonita Beach to Englewood out 20 nm-Englewood to
Tarpon Springs out 20 nm-Tarpon Springs to Suwannee
River out 20 nm.
Small Craft Advisory from 7 am to 10 PM EST Monday for
Charlotte Harbor and Pine Island Sound-Tampa Bay
Short term/aviation/marine/fire weather...02/Garcia
long term/decision support...57/McMichael