Tornadoes in Florida, December 9, 2018

Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
645 AM EST Sun Dec 9 2018

.AVIATION...
09/12Z TAF cycle. Robust LN SHRA/low CIGS/ISOLD TSRA pushing into
northern terminals with MVFR/LCL IFR conditions spreading
southward during the morning along with TSRA gusts. Greatest
impacts will be in a 14-19z window mainly from SRQ northward. LN
is expected to weaken some when approaching terminals south of
SRQ in the afternoon. VFR begins to return 20-02Z.

&&

.Prev Discussion... /issued 338 AM EST Sun Dec 9 2018/

SHORT TERM (Today - Monday)...
An upper level shortwave trough swinging through the southeastern US
today is providing the forcing for a surface low crossing northern
Florida and dragging a cold front through the eastern Gulf of Mexico
and into the Florida Peninsula. A band of showers and thunderstorms
along and ahead of this front is quickly approaching the forecast
area, and is on track to quickly push southeast through the area
during the morning through early evening hours. Strong wind shear
ahead of the front will allow for the possibility of a few strong or
severe thunderstorms, with damaging wind gusts and isolated tornadoes
the primary threat. Breezy winds both ahead of and behind the front
will also lead to a high risk of rip currents along area beaches
today, with the threat continuing through the day on Monday.

As the front pushes into the Florida Straits tonight, breezy
northwest winds behind the front will lead to a sustained period of
cold air advection. Lows Monday morning will be noticeably cooler,
ranging from the mid 40s to low 60s. The breezy winds will continue
throughout the day Monday, with afternoon highs in the upper 50s over
the Nature Coast and in the 60s over the rest of West Central and
Southwest Florida.

LONG TERM (Monday Night - Saturday)...
Monday night and Tuesday, a second shortwave trough aloft will dig
into the eastern Gulf of Mexico and Florida Peninsula, providing a
reinforcing push of cold air into the area as cold air advection
continues. Lows Tuesday morning will drop into the mid to upper 30s
north of Interstate 4, and generally in the 40s and low 50s to the
south. Highs on Tuesday will struggle to reach into the 60s in some
areas, and will only top out in the mid 60s over southwest Florida.
As high pressure fills into Florida from the northwest Tuesday night
and Wednesday, wind speeds and cold air advection will start to
subside. However, clear skies will allow temperatures to drop a
couple more degrees by Wednesday morning, and a brief freeze cannot
be ruled out in a few spots over the interior Nature Coast counties.

As broad surface high pressure settles in north of the area during
the second half of the week, temperatures will quickly moderate,
getting back to near normal by Thursday and Friday afternoon. A
strong upper/mid level trough will swing through the Mississippi
River Valley on Friday, sending the next cold front into Florida by
late Friday. This will bring another round of showers and
thunderstorms Friday and Friday night, but will only cause
temperatures to drop a few degrees by Saturday.

MARINE...
A cold front will move southeast through the coastal waters today,
producing breezy winds and periods of showers and thunderstorms.
Southerly winds ahead of the front are already increasing to advisory
levels over the Gulf waters from Englewood to Suwannee River, with
cautionary winds elsewhere. Winds will turn to the northwest and
remain around 20 knots behind the front tonight before subsiding on
Monday as high pressure builds into the western Gulf of Mexico. As
the high pressure shifts east, a tight pressure gradient will let
winds increase again slightly on Tuesday, producing exercise caution
conditions. High pressure will hold north of the waters Wednesday and
Thursday, with east winds generally around 15 knots or less.

FIRE WEATHER...
No concerns, as relative humidity will remain well above critical
levels through the next several days.

&&

.Preliminary Point Temps/PoPs...
TPA  74  56  63  47 /  80  20  20  10
FMY  77  62  69  49 /  70  20  10  10
GIF  76  55  65  43 /  80  20   0   0
SRQ  74  59  65  49 /  80  20  10  10
BKV  74  50  61  39 /  80  20  10  10
SPG  74  58  62  50 /  80  20  20  10

&&

.TBW WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Monday evening for Coastal
     Charlotte-Coastal Hillsborough-Coastal Lee-Coastal
     Manatee-Coastal Sarasota-Pinellas.

Gulf waters...Small Craft Advisory until 9 PM EST this evening for
     Coastal waters from Englewood to Tarpon Springs FL
     out 20 NM-Coastal waters from Tarpon Springs to
     Suwannee River FL out 20 NM-Waters from Englewood to
     Tarpon Springs FL out 20 to 60 NM-Waters from Tarpon
     Springs to Suwannee River FL out 20 to 60 NM.

&&

AVIATION...09/Rude
PREVIOUS...18/Fleming
 MID TERM/LONG TERM/DECISION SUPPORT...99