Scientific Forecaster Discussion
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
335 am EDT Thursday Oct 23 2014
Short term (today through friday)...weak cold front will stall
across S Florida today perhaps just S of I-75. This boundary will
continue to focus deep tropical moisture as it meanders across S Florida
through Friday. Exact position of the front and associated moisture pool will
be key as a vigorous shortwave moves across the region of Friday
providing large scale lift. Most of the County Warning Area will remain too dry for
convection...however far southern zones may be close enough to the front
and deeper moisture to see some precipitation. GFS...Canadian...NAM and
European model (ecmwf) all show frontal waves moving NE along the stalled boundary
the next few days...but models are not in any agreement with respect to timing
and location of these waves. Because of this...each model has the
front and deeper moisture in slightly different location depending
on where the waves are located in the model run. NAM is again most
aggressive with moisture as it shows a wave across the southeast Gulf on
Friday while GFS is much drier as S Florida shown to be on backside of one
of these waves which strengthens into a closed low near the Bahamas.
This continues to provide a large difference in probability of precipitation between the two
MOS products with GFS showing very little chance of precipitation while NAM
is in likely range in fmy area. Will compromise a bit between these
solutions but lean more on dry side given stronger model consensus point
that direction (20-30% far southern 5 cos). Interestingly...these
lows/frontal waves are depicted in more impressive fashion than td9
which seems to have no direct impact on the forecast as it slides
more east-southeast into the Carribean. Expect strong north/S temperature gradient tonight
as northern areas drop into the upper 40s with help of cooler and much
drier air in place but southern cos remain in the 60s closer to the
stalled boundary. Highs will generally remain near climatology with 80s
Marine...marginal Small Craft Advisory is likely occurring across the offshore
waters although there are no observation in right location to confirm.
Expect winds to drop below Small Craft Advisory later this morning then increase near
Small Craft Advisory levels again offshore again tonight as a nocturnal surge
develops across southern half of the marine area.
Fire weather...drier airmass on tap next few days...especially in northern
cos. Relative humidity values near rf thresholds...but neither winds nor erc
values support red flag at this time.
Long term(friday night-wednesday)...
progressive u/l pattern developing with a short wave disturbance moving off
the middle Atlantic coast Friday night and Saturday with a strong u/L
Ridge developing over the Southern Plains. The u/L Ridge will build
across the Gulf of Mexico and Florida Sunday with dry stable air
over the region...with mostly clear skies at night and partly cloudy
skies during the afternoon. The center of the u/L Ridge will slide
east of Florida on Monday with return flow developing as a broad u/l
trough pushes across The Rockies and into the plains on Tuesday.
Surface high pressure off the middle Atlantic coast on Tuesday will
create east to southeast boundary layer flow across the Florida
Peninsula with increasing low level moisture through middle week. On
Wednesday...southwest flow will develop aloft ahead of the u/l
trough in the plains which will gradually increase deep layer
moisture over the forecast area with a slight chance of showers
developing across the region. Temperatures will run a few degrees
above climatic normals through the period.
Preliminary point temps/pops...
tpa 83 62 83 62 / 0 0 0 0
fmy 85 67 86 63 / 20 10 30 10
gif 81 61 82 60 / 0 0 10 0
srq 86 62 83 63 / 0 0 10 0
bkv 82 51 82 51 / 0 0 0 0
spg 83 68 82 68 / 0 0 10 0
Gulf waters...Small Craft Advisory until 2 PM EDT this afternoon 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 until 10 am EDT this morning for
Bonita Beach to Englewood out 20 nm-Englewood to
Tarpon Springs out 20 nm-Tarpon Springs to Suwannee
River out 20 nm.
Short term/aviation/marine/fire weather...gittinger