Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL
FXUS62 KTBW 180943
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
443 AM EST Wed Jan 18 2017
09Z water vapor and H4 RAP analysis continues to show our
region under the protective cover of stacked mid/upper level
ridging. Looking well off to the west we find a deep trough
evolving over the SW states/northern Mexico. This energy
will migrate eastward and eventually break down the ridge
over our heads...but this will not occur with any
significance until Thursday night. Until then...our weather
will be benign...dry...with above normal temperatures.
At the surface...high pressure axis cuts across the central
Florida peninsula and eastern Gulf of Mexico...and will not
move much in the next 24 hours. Have seen a few areas of fog
across the region early this morning...but so far nothing
widespread. The arrival of cirrus aloft...in the next couple
of hours should also help to keep the fog from expanding too
great before sunrise.
.SHORT TERM (Today through Thursday)...
As mentioned in the synopsis...the ridging aloft will keep
our weather fair and warm through the short term period. The
surface ridge across the region will keep surface and
boundary layer winds quite light through Thursday. With
little to resist it, strong terrestrial heating should force
a well-defined sea-breeze moving inland this afternoon and
again on Thursday afternoon. However...unlike the
summer...there is simply not enough moisture available for
this to trigger any showers...and hence the forecast is dry.
Synoptic energy moving along the northern Gulf coast during
Thursday will likely push a band of showers/storms into the
FL panhandle late in the day...but there are no indications
from any of the guidance packages that this lift or
moisture will reach any of our zones during Thursday. There
are better chances for widespread rainfall as we head into
the second half of the upcoming weekend. You may read more
about that potential in the long term discussion below.
.Mid Term/Long Term...
An unsettled weather pattern is expected later this week and into
the weekend. A weak shortwave will move across the Deep South as a
weakening surface boundary stalls north of the area Friday into
Saturday. The presence of this boundary will support rain chances
Friday and Saturday, especially from the Bay Area north with the
Nature Coast expected to have the best rain chances at this time.
On Sunday, models continue to show a low pressure system pushing
into the Tennessee/Ohio River valleys allowing a significant trough
to develop across the eastern U.S. late this weekend and early next
week. This will allow for a front to move through the region Sunday
into Monday bringing some much needed rainfall to our area. Forecast
model soundings continue to support favorable mid/upper level
dynamics for thunderstorms with this front as it moves through the
area, perhaps even some strong to severe storms. Wont focus on too
many severe parameters at this time since we`re still a good 5 days
away but nevertheless a severe threat certainly appears possible
late Sunday into the early hours Monday.
Behind the front, cooler and drier air will filter in although temps
are only expected to return closer to climatological norms with
drier weather expected for Tuesday and Wednesday.
.AVIATION (18/06Z through 19/06Z)...
Varying conditions across the region early this
morning. As we head toward sunrise...we will continue to see
some patchy fog...with KLAL/KPGD seeing the highest
potential for an IFR period. Otherwise, generally a period
of MVFR is possible at the other terminals. VFR will then
prevails through the majority of the daylight hours after
13Z. Light SE/S winds shift SW and then W for the coastal
terminals during the later afternoon hours. Potentially
looks higher for significant visibility restrictions after
midnight tonight into early Thursday morning.
High pressure remains in control of the forecast waters through
Thursday keeping winds and seas light. Chances for a few passing
showers and some elevated winds increases Friday into
Saturday...especially across the northern and offshore waters. The
potential for sea fog development will also be increasing by Friday
and Saturday. A strong cold front is currently expected to then
approach the region during Sunday with increasing potential for a
round of thunderstorms and rough boating conditions. This front
looks to cross the region late Sunday into Sunday night with strong
west and northwest winds in its wake for the day on Monday.
No significant fire weather concerns are anticipated through
the next couple of days. Relative humidity values will
remain well above critical levels. Winds will be light
through Thursday...allowing the development of an afternoon
sea-breeze today and again Thursday. Winds near the coast
will turn onshore with the sea-breeze development. While
some showers are possible Friday into Saturday...especially
north of the I-4 corridor...confidence is increasing in a
widespread wetting rainfall later Sunday or Sunday night
with the passage of a strong cold front.
.Preliminary Point Temps/PoPs...
TPA 77 62 77 63 / 0 0 0 10
FMY 80 59 79 61 / 0 0 0 0
GIF 82 60 81 60 / 0 0 0 0
SRQ 75 60 74 60 / 0 0 0 10
BKV 79 57 79 57 / 0 0 0 10
SPG 76 62 74 63 / 0 0 0 10
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...Mroczka
MID TERM/LONG TERM/DECISION SUPPORT...McKaughan