Scientific Forecaster Discussion
fxus62 ktbw 240720
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
320 am EDT sun Sep 24 2017
Short term (today and monday)...
a highly amplified pattern exists across the Continental U.S. Today
with powerful upper level troughing across much of the
western U.S. And broad ridging over the east. A subtle upper
level low continues to meander over the northeastern Gulf
of Mexico as powerful Hurricane Maria churns just north of
the Bahamas. Weak ridging then extends to the north of Maria
into the Great Lakes and New England. Maria and the
aforementioned upper low will be the primary weather makers
over the Florida Peninsula for the next couple of days.
For today, expect conditions to be quite similar to
yesterday. With the surface ridge axis poised to the north,
low level east/northeast flow will continue across the
region. Given the upper low over the northern Gulf of Mexico
is slowly pulling away, and weak subsidence on the western
fringes of Maria is slowly encroaching on the area, we may
see lesser coverage of showers and storms today than we did
yesterday. The convective evolution, however, will generally
remain the same with storms forming by early afternoon,
moving southwestward through the late afternoon and early
evening hours, eventually moving offshore. Highs will remain
in the lower to possibly mid 90s inland and upper 80s along
The upper low over the northern Gulf will continue to
migrate westward through tomorrow. At the same time, the
surface flow pattern will become more northerly as Maria
continues to lift northward well east of the Florida
Peninsula. This will allow slightly drier air to advect into
the region. When combined with slight subsidence on the
western fringes of Maria, expect only a slight chance of a
few showers or a stray thunderstorm. This will be start of a
noted drying trend that will carry over into the start of
the coming week.
Mid/long term (monday night through sunday)...
a rather uneventful forecast for the mid and long term
period across west-central and SW Florida. As Hurricane
Maria continues to move north across the western Atlantic,
drier air will filter down across the area. Precipitable
water values will drop into the 1.3 - 1.5 inch range across
the County Warning Area on Tuesday and continuing into Thursday. This drier
air will make it very difficult to see any shower/storm
development so no rain chances in the forecast by late week,
models begin to indicate moisture return from the south so
sct rain chances will again return to the forecast.
Nevertheless, much of this week looks hot and dry for most.
Temperatures will top out near 90 daily with lows in the low
to mid 70s.
Aviation (06z tafs)...
light northeast winds and VFR conditions to prevail through
around 17z to 18z, when widely scattered showers and storms
are expected to develop. Will maintain thunderstorms in the vicinity all terminals
for this possibility. Activity should move offshore by 00z
with a return to VFR conditions.
breezy northeast winds to around 15 knots will persist for
a few hours this morning, especially over the offshore
waters. Winds will decrease during the late morning and
afternoon. The pressure gradient will slacken as we head
into next week with light north to northeast winds shifting
onshore each afternoon with the seabreeze. A few marine
thunderstorms may occur this afternoon into tonight with dry
conditions expected as we head into next week.
scattered afternoon showers and storms will remain possible
today and tomorrow with drier conditions forecast for much
of the coming week. Despite drier than normal conditions,
and warm temperatures, humidities look to remain well above
critical levels and no fire weather concerns are expected.
Preliminary point temps/pops...
tpa 90 75 90 76 / 40 10 10 0
fmy 90 74 91 75 / 50 30 20 0
gif 90 73 92 73 / 30 10 20 10
srq 89 74 88 75 / 40 20 10 0
bkv 91 71 91 71 / 30 10 10 10
spg 89 76 89 76 / 40 10 10 0