Scientific Forecaster Discussion
fxus62 ktbw 182337
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
637 PM EST Thu Jan 18 2018
prevailing VFR conditions through the taf period with
varying winds out of the northeast to northwest. High
cirrus will stream across the region from the southwest with
the thickest clouds residing over our southern terminals.
Prev discussion... /issued 225 PM EST Thu Jan 18 2018/
Short term (tonight-friday)...
the biggest forecast challenges for the short term period is the
minimum temperature for tonight/Friday morning. The night should set
up quite nicely for radiational cooling with high pressure, clear
skies, and light winds. Based on this setup and the knowledge that
spots in the interior portion of our forecast area can end up quite a
bit cooler than model guidance suggests, have opted to expand the
freeze warning to include interior Manatee, interior Sarasota,
Hardee, DeSoto, and Highlands counties. The biggest caveat lies with
the wind direction right off the surface. If winds go more easterly
a couple of thousand feet up, that will slow The Drop in temperatures
and a freeze for the Manatee/Sarasota area east to Highlands may not
happen. The hard freeze for counties to the north looks good. Frost
formation is also likely for parts of the interior, but exactly where
depends on how low the dew points end up getting.
High pressure remains overhead through Friday, so we will see plenty
of sun again. The only difference is that Friday afternoon will end
up being about 10 degrees warmer than today.
Long term (friday night-thursday)...
aloft - during the weekend a short wave trough tracks along the Gulf
Coast and the southeast U.S. Coast while a low drops into the
central rockies and slides out over the Central Plains. A ridge
extends over the Caribbean from the Atlantic. Next week the low
moves northeast...across the Great Lakes and into eastern Canada...
while troughiness continues into the Gulf of Mexico. The Caribbean
ridge nudges north to Cuba. Surface - high pressure across the
southeastern states and eastern Gulf slides east through Mon. On Tue
a surface reflection of the upper low trails a cold front through
the Gulf...across Florida...and out over the Atlantic. High pressue slips
in behind the front...over the central Gulf Coast Wed then into the
eastern states Thu.
Northeasterly low level flow with temperatures slightly below normal
will gradually veer to southerly by Mon and early Tue and allow the
temperatures to warm to above normal. The front on Tue shifts flow
to northerly then the high behind the front will shift the flow to
northeasterly...with the temperatures cooling a bit but staying near
normal. The fairly quick turn of the winds and the high pressure
coming in from the Southern Plains will limit any cool to cold air.
Increasing moisture will support isolated to scattered showers
starting sun and continuing as the front approaches. The upper
trough hanging back over the Gulf will provide enough energy for
some showers through the end of the period.
VFR conditions are expected through the forecast period.
strong northerly winds across portions of the Gulf waters this
morning will continue to diminish through the next several hours
with no headlines in place by this afternoon. High pressure will
remain over the region through the next couple of days, with lighter
winds in place through the weekend. Another cold front will approach
the waters early next week, with winds becoming more southerly.
Patchy sea fog may occur ahead of this front as moisture increases.
several hours of critically low relative humidity values are
expected for Friday afternoon, mainly north of the I-4 corridor. Erc
values and winds, however, do not appear to meet red flag criteria
at this time. Relative humidity values will remain above critical
levels for the weekend and into early next week. No significant fog
is expected for the next several days.
Preliminary point temps/pops...
tpa 36 62 47 68 / 0 0 0 0
fmy 40 68 52 72 / 0 0 0 10
gif 35 64 46 70 / 0 0 0 0
srq 35 62 49 68 / 0 0 0 10
bkv 25 61 39 69 / 0 0 0 0
spg 41 61 49 68 / 0 0 0 10
Florida...hard freeze warning from midnight tonight to 9 am EST
Friday for coastal Citrus-coastal Hernando-coastal
Levy-inland Citrus-inland Hernando-inland Levy-inland
Freeze warning from midnight tonight to 9 am EST Friday
for coastal Pasco-DeSoto-Hardee-Highlands-inland
Hillsborough-inland Manatee-inland Sarasota-Polk.