Area Forecast Discussion
Issued by NWS Tampa Bay Area, FL

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FXUS62 KTBW 201919
AFDTBW

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
219 PM EST Mon Jan 20 2020

...FREEZING TEMPERATURES EXPECTED ALONG NATURE COAST TONIGHT...

.DISCUSSION...
A highly amplified upper level pattern has set up over the CONUS to
start out the week. Sharp ridging extends from the four corners
region northward into Saskatchewan Canada. Farther east, a closed
upper low spins over Iowa with broad upper troughing extending over
the eastern half of the U.S. This upper low will transit southeast
through the base of the trough over the next couple of days bringing
more cold air with it down from Canada. The upper low will exit the
southeast coast late Tuesday into Wednesday with upper ridging
building through the Mississippi River Valley. This upper pattern
will be the perfect set up to advect more cold air into the region
on Tuesday night/Wednesday morning. The ridge axis moves along the
east coast late Wednesday into Thursday, which will start the
transition to a warming trend through the end of the week. Another
upper low and trough approaches the east coast through the weekend
and will lend support to the next cold front.

On the surface, the trailing edge of a cold front currently extends
across the Florida Keys. Strong high pressure over the central U.S.
will build in behind this front bringing clear skies and much colder
weather to the region over the next few days. The daytime highs on
Tuesday and Wednesday will top out only in the upper 50`s to mid
60`s. The coldest weather we have seen this winter is expected
tonight and Tuesday night. Temperatures below freezing will be
possible the next 2 nights over the inland portions of the counties
along the Nature Coast and freezing temps possible farther south and
inland on Tuesday night. Winds chills will bottom out around 28 to
35 degrees over the inland counties north of I-4 tonight and 25 to
30 degrees for most of west central and southwest Florida Wednesday
morning. A Freeze Warning is in effect for Levy County during the
early morning hours on Tuesday and a Freeze Watch for Hernando
County northward early Wednesday morning. Further Freeze Warnings
and Wind Chill Advisories will likely be needed for Tuesday night
into Wednesday morning.

The next weather system develops through the Mississippi River
Valley with a cold front extending into the central Gulf of Mexico
late Thursday into Friday. Winds turn southeast, then southwest
ahead of this system and will warm things up on Thursday and Friday.
This system will move east with the cold front moving across Florida
on Friday bringing increasing rain chances. Another slight cool down
is expected Saturday and continuing into the beginning of next week.

&&

.AVIATION...
VFR conditions with northerly winds between 8-10 knots through the
period.

&&

.MARINE...
Interaction between a cold front over southern Florida and strong
high pressure over the central U.S. is producing gusty northerly
winds across the eastern Gulf of Mexico. Have let the SCA expire at
10 am, but will continue to hold SCEC for all waters today and
tonight. Onshore wave action will produce a high risk of rip
currents at local beaches through the day. The gradient further
tightens on Tuesday afternoon between the high pressure over the
Ohio River Valley and a trough of low pressure near the Bahamas,
which will likely bring conditions back up to SCA level continuing
through Wednesday afternoon. The high moves off the mid-Atlantic
coast by Thursday which will bring the winds around to the east and
will decrease below any SCA or SCEC level to close out the week.

&&

.FIRE WEATHER...
Colder and drier air has filtered into the area behind the front
today, with relative humidity percentages dropping into the mid 30s
for a few hours in some locations this afternoon and again Tuesday
afternoon. However, wind speeds are not expected to be high enough
to warrant the issuance of any Red Flag Warnings.

&&

.Preliminary Point Temps/PoPs...
TPA  40  56  36  60 /   0   0   0   0
FMY  46  61  37  63 /   0   0   0   0
GIF  40  56  34  60 /   0   0   0   0
SRQ  41  58  37  62 /   0   0   0   0
BKV  34  56  31  60 /   0   0   0   0
SPG  46  57  38  61 /   0   0   0   0

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Freeze Watch from late Tuesday night through Wednesday morning
     for Coastal Citrus-Coastal Hernando-Coastal Levy-Inland
     Citrus-Inland Hernando-Inland Levy-Sumter.

     High Rip Current Risk until 9 PM EST this evening for Coastal
     Charlotte-Coastal Hillsborough-Coastal Lee-Coastal Manatee-
     Coastal Sarasota-Pinellas.

     Freeze Warning from 3 AM to 9 AM EST Tuesday for Coastal Levy-
     Inland Levy.

Gulf waters...None.

&&

$$

DISCUSSION/AVIATION/MARINE/FIRE WEATHER...74/Wynn
DECISION SUPPORT...69/Close



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