Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
341 am EDT Sat Jul 23 2016
Short term (today - sunday)...
early morning water vapor satellite imagery is showing a large
circulation around an upper level ridge of high pressure over the
southeastern states and northern Gulf of Mexico, while an
elongated upper level trough off the East Coast of the US is
bringing some drier air aloft into the East Coast of Florida.
Through the rest of the weekend, this ridge will largely hold in
place, while the southern extent of the trough will break off as a
cut off low and drift west across the Florida Peninsula. This will
bring a somewhat drier atmospheric column into the area, with some
small amount of suppression to the thunderstorm activity. However,
moisture will remain abundant in the low levels, which combined
with strong surface heating will ensure scattered to numerous
thunderstorms will still develop each afternoon. The surface ridge
of high pressure is forecast to remain across northern Florida
through the weekend, keeping generally southeast winds in place.
This will favor a sea breeze collision over the western half of
the Florida Peninsula, and provide a focus for thunderstorms
during the late afternoon and early evening hours.
Temperatures will remain near normal, with highs in the low 90s,
except for some upper 80s along the coast. Lows tonight will range
from the low 70s inland to upper 70s along the coast.
Long term (monday through next friday)...
the long term portion of the forecast will start out on Monday
with an upper low feature that will reside over the Florida Peninsula
during the second half of the weekend...beginning to exit to our
west over the Gulf of Mexico. Throughout the day the influence of
this energy aloft will decrease. Throughout the remainder of the
forecast period...mid/upper level ridging will be in control of
our weather...with the ridge center slowly migrating from off the
Carolina coast during Tuesday...to a position over the northern
Florida Peninsula by Friday.
At the surface...the subtropical ridge axis will remain in a general
position across the northern Florida Peninsula...placing much of our
region within a zone of light to moderate east/southeast synoptic
low level flow. From a climatology standpoint...this flow is our
most convectively active wind regime related to the sea-breeze...and
the regime that produces the best potential for a few stronger
storms during the afternoon/evening. Of course that is climatology.
Subtle variations in mid-level moisture and low level wind speed can
have a big influence on how much storm coverage we see from day to
day. Unless the changes are large in scale (expansive swaths of
dry/moist air resolved well by all guidance members)...it is
difficult to predict these day to day variations all that far in
advance. So...for now...will keep our sensible weather forecast near
climo for the east/southeast wind flow...with highest pops during the later
afternoon/early evening along the West Coast of the Florida Peninsula.
patches of low clouds are lingering around Tampa Bay, with some
IFR/LIFR ceilings possible at area taf sites through the next
few hours. Scattered thunderstorms will develop again during the
early afternoon, with periods of IFR or MVFR ceilings and
visibilities expected through early evening in the vicinity of
the storms. Generally VFR conditions will take hold again after
broad high pressure ridging across the northern Gulf of Mexico will
keep light and generally southerly to southeasterly winds in place
over the coastal waters through the next several days. Winds will
turn onshore near the coast each afternoon with the sea breeze.
Winds and seas will remain light through the start of next week,
except in the vicinity of thunderstorms where hazardous boating
conditions will be possible.
no fire weather concerns through the forecast period.
Preliminary point temps/pops...
tpa 90 77 91 76 / 30 30 50 30
fmy 90 75 89 75 / 50 30 60 20
gif 92 74 92 74 / 40 20 50 20
srq 89 76 89 76 / 40 20 50 30
bkv 92 72 92 72 / 30 20 40 30
spg 90 78 90 78 / 30 30 40 30
Short term/aviation/marine/fire weather...18/Fleming
middle term/long term/decision support...14/mroczka