[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 031754
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST THU DEC 03 2015

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF
SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM THE
EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON SATELLITE
IMAGERY...WEATHER OBSERVATIONS...RADAR...AND METEOROLOGICAL
ANALYSIS.

BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1715 UTC.

...SPECIAL FEATURES...                                         A
A COLD FRONT IS ANALYZED FROM CENTRAL FLORIDA JUST SOUTH OF
TAMPA BAY SW TO NEAR 21.5N94.5W THEN TURNS SHARPLY SOUTHWARD
ACROSS THE CENTRAL BAY OF CAMPECHE AND CONTINUES INLAND FROM
ABOUT 20 MILES EAST OF COATZACOALCOS MEXICO TO EASTERN PORTIONS
OF THE ISTHMUS OF TEHUANTEPEC. A STRONG PRESSURE GRADIENT
BETWEEN THE FRONT AND 1028 MB HIGH PRESSURE ACROSS NE MEXICO IS
GENERATING GALE FORCE NORTHERLY WINDS S OF 21N W OF 94W...WHILE
NORTHERLY WINDS 20-30 KT PREVAIL ELSEWHERE W OF THE FRONT S OF
26N...AND GALES HAVE BEGUN ON THE PACIFIC SIDE OF THE ISTHMUS
ACROSS THE GULF OF TEHUANTEPEC. THESE NORTHERLY GALES ARE
EXPECTED TO SHIFT SLIGHTLY SOUTHWARD BY AFTERNOON...TO THE BAY
OF CAMPECHE WATERS SOUTH OF 20N...AND INCREASE TO 40 KT BEFORE
GRADUALLY DIMINISHING BELOW GALE FORCE TONIGHT. SEE THE LATEST
FORECAST UNDER AWIPS/WMO HEADERS MIAHSFAT2/FZNT02 KNHC FOR MORE
DETAILS.

...ITCZ/MONSOON TROUGH...

MODEL DATA AND OBSERVATIONS SUGGEST THAT THERE IS NO MONSOON
TROUGH PRESENT ACROSS THE W AFRICAN REGION. THE INTERTROPICAL
CONVERGENCE ZONE AXIS EXTENDS FROM CAMEROON NEAR 10N10E TO
02N05E TO 06N23W TO 03.5N38W TO NEAR THE MOUTH OF RIO OIPOQUE
NEAR 04N52W. WIDELY SCATTERED MODERATE TO STRONG CONVECTION IS
WITHIN 90 NM OF AXIS 05E-05W. SCATTERED MODERATE ISOLATED STRONG
CONVECTION IS WITHIN 120 NM S AND 210 NM N OF AXIS FROM 31W-52W.

...DISCUSSION...

GULF OF MEXICO...                                              A
VIGOROUS MIDDLE TO UPPER LEVEL LOW IS NOTED IN WATER VAPOR
IMAGERY SHIFTING NE AND OUT OF THE GREAT LAKES REGION...WITH A
SOMEWHAT BROAD MIDDLE TO UPPER TROUGH TRAILING SOUTHWEST OVER
THE MID-MISSISSIPPI RIVER VALLEY AND SOUTHERN PLAINS TO NORTHERN
MEXICO THEN THE SOUTHERN TIP OF BAJA MEXICO. THE TROUGH IS
SUPPORTING A COLD FRONT EXTENDING CENTRAL FLORIDA JUST SOUTH OF
TAMPA BAY SW TO NEAR 21.5N94.5W THEN TURNS SHARPLY SOUTHWARD
ACROSS THE CENTRAL BAY OF CAMPECHE AND CONTINUES INLAND
FROMALONG THE MEXICAN COAST NEAR 18N94W TO EASTERN PORTIONS OF
THE ISTHMUS OF TEHUANTEPEC. BROKEN TO OVERCAST MULTILAYERED
CLOUD COVER BLANKET MOST OF THE GULF NW OF THE FRONT...WHERE
LIGHT TO MODERATE STRATOFORM PRECIP CONTINUES TO MOVE NE ACROSS
THE BASIN. SATELLITE IMAGERY SUGGESTS ISOLATED MODERATE
CONVECTION OCCURRING ALONG THE FRONT ACROSS CENTRAL AND SW
SECTIONS. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED FROM THE
EXTREME NW BAHAMAS SW THROUGH THE STRAITS OF FLORIDA TO THE
YUCATAN CHANNEL...WHERE ABUNDANT LOW LEVEL MOISTURE IS
CONVERGING BOTH E AND W OF TROUGH. SCATTERED STRONG CONVECTION
CONTINUES TO FIRE ALONG AND E OF THE TROUGH FROM THE FLORIDA
KEYS S-SW ACROSS W CUBA AND INTO THE NW CARIBBEAN.
OUTSIDE OF THE STRONG NORTHERLY WINDS S OF 26N MENTIONED
ABOVE...N TO N-NE WINDS OF 15-20 KT GENERALLY PREVAIL BEHIND THE
FRONT AND N OF 26N. SEAS ARE BUILDING QUICKLY BEHIND THE
FRONT...WHERE BUOY 42055 IN THE SW GULF HAS ALREADY REACHED 15
FT. THE REMAINDER OF THE BASIN IS UNDER THE INFLUENCE OF GENTLE
TO MODERATE NORTH TO NORTHEAST WINDS PRECEDING THE COLD FRONT.
THE FRONT IS FORECAST TO MOVE SOUTHEAST THROUGH TONIGHT AND
STALL FROM EXTREME SOUTH FLORIDA ACROSS NW PORTIONS OF THE
STRAITS OF FLORIDA AND THROUGH THE W YUCATAN CHANNEL...WHERE IT
WILL LIKELY MEANDER THROUGH SATURDAY. WINDS AND SEAS WILL
SUBSIDE CONSIDERABLY ACROSS SW PORTIONS OF THE GULF TONIGHT
THROUGH FRIDAY...WHILE NE WINDS 20-25 KT ARE EXPECTED TO PERSIST
BEHIND THE STALLED FRONT FOR SOME 200-240 NM TO THE NW THROUGH
SAT.

CARIBBEAN SEA...

A TUTT LOW LINGERS OVER THE WINDWARD PASSAGE AND WESTERN
HISPANIOLA NEAR 19N73W...AND IS BEGINNING TO DRIFT EASTWARD AS
THE LONG WAVE TROUGH ACROSS THE NE AND CENTRAL U.S. CONTINUES TO
TO SHIFT E AND SE. THE ASSOCIATED DYNAMICAL LIFT CREATED BY
THISLOW IS COMBINING WITH LOW LEVEL MOISTURE ACROSS HISPANIOLA
AND THE SURROUNDING WATERS TO PRODUCE WIDELY SCATTERED SHOWERS
AND ISOLATED TSTMS ALL ALONG THE SRN COASTS OF HISPANIOLA WITH
DYING OVERNIGHT CONVECTION ACROSS MUCH OF INTERIOR DOMINICAN
REPUBLIC. TO THE WEST...SHARP UPPER LEVEL RIDGING IS NOTED ON
WATER VAPOR IMAGERY AND PROVIDING DIVERGENCE ALOFT TO ENHANCE
SCATTERED TO NUMEROUS SHOWERS AND TSTMS ALONG AND WITHIN 180 NM
E OF A LINGERING SURFACE TROUGH ANALYZED FROM 21N85W TO 16N88W
AND THE GULF OF HONDURAS. MORNING SCATTEROMETER DATA SHOWS FRESH
TO STRONG EASTERLY TRADEWINDS PREVAILING ACROSS CENTRAL PORTIONS
OF THEBASIN...WITH MODEL GUIDANCE INDICATING THESE TRADES
BETWEEN 64W AND 77W. A STRONG ATLANTIC RIDGE PROMOTING THESE
TRADES WILLSHIFT E-NE DURING THE NEXT 36-48 HOURS WITH THE
WEAKENING PRESSURE GRADIENT SUPPORTING A MODEST DECREASE IN THE
TRADES FRI THROUGH SAT.

...HISPANIOLA...

THE TUTT LOW OVER THE WINDWARD PASSAGE AND WESTERN HISPANIOLA
HAS WEAKEN SLIGHTLY OVERNIGHT...BUT CONTINUES TO SUPPORT WIDELY
SCATTERED SHOWERS AND ISOLATED TSTMS ALL ALONG THE SRN COASTS OF
HISPANIOLA WITH DYING OVERNIGHT CONVECTION ACROSS MUCH OF
INTERIOR DOMINICAN REPUBLIC. THE TUTT LOW WILL SHIFT SLOWLY E
TODAY TO MAINTAIN UNSTABLE CONDITIONS BEFORE STABILIZING
CONDITIONS BEGIN TO AFFECT HAITI TONIGHT. AMPLE MOISTURE EMBEDDED
IN THE E-SE LOW LEVEL FLOW WILL FOCUS DIURNAL CONVECTION ACROSS
PREFERRED REGIONS OF INTERIOR AND N CENTRAL HISPANIOLA THIS
AFTERNOON AND EVENING...WITH NOCTURNAL SHOWERS AND ISOLATED
TSTORMS TONIGHT ALONG EASTERN COASTAL PORTIONS.

ATLANTIC OCEAN...

MOIST SOUTHWESTERLY FLOW ALOFT PREVAILS OVER NW PORTIONS OF THE
SW NORTH ATLC WITH A COLD FRONT ANALYZED ENTERING THE AREA NEAR
31N76.5W TO CENTRAL FLORIDA JUST N OF CAPE CANAVERAL. LOW-LEVEL
MOISTURE SOUTHEAST OF THE FRONT IS CONVERGING ALONG A SURFACE
TROUGH FROM 31N76W TO 25.5N80W THEN THROUGH THE STRAITS OF
FLORIDA...WHERE SCATTERED MODERATE TO STRONG CONVECTION IS
OCCURRING ALONG AND UP TO 90 NM SE OF THE TROUGH. THE FRONT
WILL CONTINUE TO SHIFT E-SE THROUGH FRI...REACHING FROM NEAR
BERMUDA TO PALM BEACH FLORIDA TONIGHT...WHERE W PORTIONS OF THE
FRONT WILL STALL THROUGH SAT. CONDITIONS ACROSS THE FAR WESTERN
SW NORTH ATLC WATERS NEAR THE FRONT WILL REMAIN UNSTABLE UNTIL
FRONTAL PASSAGE BY FRIDAY MORNING. A BROAD HIGH PRESSURE RIDGE
PREVAILS SE OF THE FRONT...ANCHORED ON A 1037MB HIGH NEAR
38N36W. THE RIDGE WILL SHIFT E-NE AND WEAKEN THROUGH SAT
ASTHEFRONT CONTINUES MOVING EWD AT MID LATITUDES. THEN THROUGH
THE WEEKEND THE FRONT WILL BECOME MORE EAST-WEST ORIENTED AND
BECOME QUASISTATIONARY FROM ALONG 29N/30N TO THE NW BAHAMAS AND
EXTREME S FLORIDA...WITH STRONG TO NEAR GALE NE WINDS ARE
EXPECTED DUE TO A STRENGTHENED PRESSURE GRADIENT GENERALLY N OF
27N W OF 67W.

FARTHER SE...THE TUTT LOW OVER WESTERN HISPANIOLA SUPPORTS A
WEAK SURFACE FROM 22N71.5W TO THE WINDWARD PASSAGE.
CONVECTIONACROSS HISPANIOLA AND THE ADJACENT ATLANTIC WATERS
OVERNIGHT AND THIS MORNING WAS ASSOCIATED WITH MOISTURE
ACCOMPANYING THIS TROUGH. THE TROUGH WILL BECOME DIFFUSE TODAY
AS IT MOVES INTO THE W PERIPHERY OF THE ATLANTIC RIDGE.
OTHERWISE...THE REMAINING SIGNIFICANT FEATURE ACROSS THE EASTERN
AND CENTRAL ATLC IS A COLD FRONT ANALYZED WITHIN THE SOUTHERN
PERIPHERY OF A RIDGE FROM 32N24W SW TO 25N40W BECOMING
STATIONARY AND WEAKENING TO 23N46W. SCATTERED SHOWERS ARE
OCCURRING WITHIN 120 NM EITHER SIDE OF THE FRONT E OF 35W.

FOR ADDITIONAL INFORMATION PLEASE VISIT
HTTP://WWW.HURRICANES.GOV/MARINE

$$
STRIPLING
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