Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion 
National Weather Service Tampa Bay Ruskin Florida
236 PM EDT Friday Aug 1 2014

Short term (tonight - saturday)...
an amplified upper level pattern over the Continental U.S. Consisting of a
strong upper ridge out west near The Four-Corners region and a
deep broad upper level trough over the eastern U.S. Will persist
through the short term period. As for the rest of this afternoon
should continue to see scattered showers and storms develop along
the inland moving sea breeze boundaries with highest rain chances
and coverage of storms focusing over central and southern interior
locations from Orlando southwest to fort Meyers where the deepest
moisture and best sea breeze convergence should reside...with the
convection lingering into the early evening hours. A weak steering
flow will favor slow moving storms with some locally heavy rainfall
amounts possible...along with some gusty winds and frequent
lightning strikes.

Weakening boundary interactions combined with loss of daytime
heating will allow the convection to wind down after sunset...with
convective debris clouds thinning with partly cloudy skies expected
overnight. It will be a mild and muggy night with overnight lows
ranging from the lower 70s north...and middle 70s central and south
except upper 70s to around 80 along the immediate coast.

On Saturday deep moisture (pw's at or above 2 inches) will continue across
the forecast area. This moisture combined with daytime heating the
sea breeze circulations and a weak inverted trough approaching from
the east will support scattered to numerous showers and thunderstorms
across the region with the convection developing and increasing in
areal coverage from middle morning on with highest probability of precipitation (50 to 60
percent) likely to set up along the I-75 corridor during the
afternoon and early evening hours as the east southeast flow
strengthens a bit. The deep moisture combined with a weak steering
flow will support slow moving storms so the potential for some
heavy rainfall amounts in some locations will continue. In addition
frequent lightning strikes and gusty winds will accompany the
storms.

Temperatures on Saturday will be again within a degree or two of
seasonal norms with highs climbing into the upper 80s to around 90
along the coast...and lower to middle 90s inland.



Long term (saturday night - friday)...
weather pattern for Sunday and Monday of next week looks to be
one that will be convectively active for our forecast area as
persistent East Coast troughing continues to hold the main upper
ridge to the east of the state. Deep column moisture in
place...along with a lack of any appreciable synoptic suppression
aloft should allow for a favorable environment to support numerous
diurnal showers and storms. The overall low level flow is now
forecast by the main global models to be very light in nature...as
opposed to 24 hours ago when a more southeasterly flow was
forecast. The lighter flow would suggest the greatest coverage of
storms will be across the interior and southern portions of the
forecast area as both east and West Coast sea-breeze boundaries
are able to push inland. This is not to say that the beaches will
be dry...as would expect early storms (midday/early afternoon) to
develop closer to the beaches. However...once the sea-breeze makes
some progress inland...these rain chances may decrease once again
along the coast while rain chances quickly increase to the the
east of the I-75 corridor. Although not specifically shown in the
forecast at this time...the most favorable environment for deep
convection may actually set up for the day on Monday when some
synoptic help for ascent looks to be in place within the rrq of a
60-70 knot upper jet aligned along the eastern Seaboard.

Temperatures both Sunday and Monday look to be near or slightly
below climatology due to a greater coverage of storms and resulting high
level cirrus canopy each afternoon/evening.

Heading into the middle and later portion of next week...this wetter
and more ill-defined pattern will begin to be replaced once again by
middle/upper level ridging trying to build back in from the Atlantic.
Both the GFS/European model (ecmwf) show our heights increasing with time...with the
European model (ecmwf) being the more aggressive (stronger ridge) over the past 2-3
run cycles. Either way...we should expect to see our rain chances
returning closer to climatology or even below climatology by Wed/thurs...along
with hotter temperatures. The forecast is currently based on a blend
of the GFS and European model (ecmwf). If the stronger European model (ecmwf) was to verify...then
rain chances may be even lower for the middle of the week. Plenty of
time to watch this pattern evolve and make any necessary forecast
adjustments.

&&

Aviation...
developing rain showers/thunderstorms and rain may bring brief MVFR/IFR conditions to kpgd
kfmy and krsw terminals through 21z and have handled with short
tempo groups with thunderstorms in the vicinity being depicted at ksrq and klal...otherwise
VFR will prevail. West to northwest winds in the 6 to 8 knot range
with gusts up to 40 knots possible in the vicinity of thunderstorms and rain will
become variable at or below 5 knots after 01z tonight.

&&

Marine...
winds and seas will remain well below headline criteria tonight
through early next week as a weak pressure pattern remains over
the region. A trough of low pressure moving into the region during
the weekend will enhance thunderstorm activity...with higher winds
and seas expected in the vicinity of the storms.

&&

Fire weather...
ample moisture and elevated rain chances will keep humidity values
well above critical levels through early next week with no fire
weather issues or concerns expected at this time.

&&

Preliminary point temps/pops...
tpa 76 92 77 92 / 10 40 30 60
fmy 76 93 77 92 / 40 60 40 70
gif 75 93 76 93 / 40 60 50 70
srq 76 92 76 91 / 10 40 30 40
bkv 72 92 72 92 / 10 40 30 60
spg 79 90 80 91 / 10 40 30 50

&&

Tbw watches/warnings/advisories...
Florida...none.
Gulf waters...none.
&&

$$

Short term/aviation/fire weather...57/McMichael
long term...14/mroczka
marine...11/mckaughan
decision support...18/Fleming

National Weather Service Glossary of Abbreviations