Tropical Weather Discussion
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000
AXNT20 KNHC 231115
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST TUE DEC 23 2014

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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...SPECIAL FEATURE...

A GALE WARNING IS IN EFFECT FOR THE WESTERN GULF OF MEXICO TUE
EVENING THROUGH WED EVENING. A COLD FRONT CURRENTLY OVER CENTRAL
TEXAS WILL APPROACH THE NW GULF TODAY...MOVING INTO THE TEXAS
AND WESTERN LOUISIANA COASTAL WATERS THIS AFTERNOON. NORTHERLY
WINDS WILL RAPIDLY INCREASE TO GALE FORCE BEHIND THE FRONT
MAINLY W OF 94W. THE FRONT IS FORECAST TO REACH FROM S CENTRAL
LOUISIANA TO NEAR TAMPICO MEXICO THIS EVENING...FROM MOBILE BAY
TO THE CENTRAL BAY OF CAMPECHE WED MORNING...FROM TAMPA BAY TO
THE YUCATAN CHANNEL WED EVENING...PUSHING SE OF THE GULF BY THU
MORNING WHEN IT IS EXPECTED TO MOVE ACROSS SOUTH FLORIDA. A BAND
OF SHOWERS AND TSTMS WILL BE ASSOCIATED WITH THE FRONT. HIGH
PRESSURE WILL BUILD IN THE WAKE OF THE FRONT ACROSS THE GULF
REGION.

...THE ITCZ/THE MONSOON TROUGH...

THE MONSOON TROUGH CROSSES THE COAST OF AFRICA NEAR 07N11W AND
CONTINUES OVER THE E ATLC WATERS TO NEAR 04N19W. THE ITCZ BEGINS
NEAR 04N19W AND CONTINUES ALONG 2.5N30W TO 02N40W TO THE COAST
OF SOUTH AMERICA AT 02N51W. SCATTERED MODERATE CONVECTION IS
NOTED FROM 3N-5N BETWEEN 16W AND 18W.

...DISCUSSION...

GULF OF MEXICO...

MODERATE TO FRESH SOUTHERLY WINDS ARE NOTED PER SCATTEROMETER
AND SURFACE DATA ACROSS THE GULF REGION BETWEEN THE ATLANTIC
RIDGE THAT DOMINATES THE EASTERN GULF AND LOWER PRESSURE OVER
THE WESTERN GULF AND TEXAS. THIS SOUTHERLY RETURN FLOW WILL
INTENSIFY...AS PRES GRADIENT TIGHTENS ACROSS THE AREA...AND
SPREAD OVER THE ENTIRE GULF TODAY AHEAD OF A STRONG COLD FRONT
EXPECTED TO ENTER THE NW GULF THIS AFTERNOON. SEE SPECIAL
FEATURE FOR DETAILS. MOSAIC DOPPLER RADAR FROM THE SE U.S. SHOWS
INCREASING SHOWERS AND TSTMS ACROSS THE NORTHERN GULF FROM THE
MISSISSIPPI DELTA TO THE FLORIDA BIG BEND...AND THEN ACROSS
NORTHERN FLORIDA. THIS CONVECTIVE ACTIVITY OVER FLORIDA IS
ASSOCIATED WITH A WARM FRONT. A FEW STRONG TSTMS ARE POSSIBLE
NEAR THE GULF COAST TODAY. IN THE UPPER LEVELS...SW FLOW
DOMINATES THE ENTIRE GULF WATERS AHEAD OF A LONG-WAVE TROUGH
THAT CROSSES WESTERN TEXAS AND NORTHERN MEXICO. THESE WINDS ARE
TRANSPORTING ABUNDANT MID TO UPPER LEVEL MOISTURE ACROSS THE
GULF OF MEXICO AND FLORIDA INTO THE WESTERN ATLC. THIS TROUGH
SUPPORTS THE AFOREMENTIONED COLD FRONT.

CARIBBEAN SEA...

FRESH TO STRONG TRADEWINDS ARE BLOWING ACROSS THE EAST AND
CENTRAL CARIBBEAN WITH THE STRONGEST WINDS OF 25-30 KT NEAR THE
COAST OF COLOMBIA. SCATTEROMETER PASSES CONFIRMED THE PRESENCE
OF THESE WINDS. MODERATE TO LOCALLY STRONG E TO SE WINDS ARE
NOTED OVER THE WESTERN CARIBBEAN. SHALLOW MOISTURE EMBEDDED IN
THE TRADE WIND FLOW CONTINUES TO MOVE ACROSS THE REGION
PRODUCING ISOLATED TO SCATTERED PASSING SHOWERS. NOW...THEY ARE
MORE CONCENTRATED OVER THE NW CARIBBEAN. PATCHES OF LOW LEVEL
MOISTURE ARE CURRENTLY MOVING ACROSS THE LESSER ANTILLES FROM
THE ATLANTIC. SOME OF THEM ARE ALSO REACHING THE UK/US VIRGIN
ISLANDS. SHOWERS CARRIED BY THE WINDS ARE ALSO AFFECTING THE
ISLANDS NEAR THE COAST OF VENEZUELA AND THE ABC ISLANDS. FRESH
TO STRONG TRADE WINDS WILL PREVAIL OVER THE CENTRAL CARIBBEAN
THROUGH SAT NIGHT. A STRONG COLD FRONT IS EXPECTED TO MOVE INTO
THE NW CARIBBEAN WED NIGHT. THE FRONT WILL EXTEND FROM WESTERN
CUBA TO CENTRAL HONDURAS THU MORNING WHERE IT WILL GRADUALLY
WASH OUT AND DISSIPATE THROUGH FRI MORNING. STRONG NW TO N WINDS
AND BUILDING SEAS ARE EXPECTED W OF THE FRONT. IN THE UPPER
LEVELS...A RIDGE WITH AXIS ACROSS HISPANIOLA COVERS MOST OF THE
BASIN PRODUCING STRONG SUBSIDENCE ACROSS THE CARIBBEAN SEA...
MOST OF CENTRAL AMERICA AND NORTHERN COLOMBIA AND VENEZUELA. MID
TO UPPER LEVEL MOISTURE IS ON INCREASE OVER THE FAR NW CARIBBEAN
AND WESTERN CUBA WHERE A SWLY FLOW ALOFT PREVAILS.

HISPANIOLA...

FAIR WEATHER PREVAILS OVER THE ISLAND AS A BROAD UPPER-LEVEL
RIDGE WITH STRONG SUBSIDENCE PERSISTS. SIMILAR CONDITIONS ARE
EXPECTED OVER THE NEXT 24 HOURS WITH LOW-TOPPED TRADE WIND
SHOWERS MOVING MAINLY ACROSS THE CARIBBEAN WATERS.

ATLANTIC OCEAN...

A 1023 MB HIGH PRES LOCATED ENE OF BERMUDA NEAR 33N61W EXTENDS A
RIDGE SE TO NEAR 20N43W. ANOTHER RIDGE STRETCHES FROM THE SAME
SYSTEM TO THE SW REACHING FLORIDA...CUBA AND THE NW CARIBBEAN.
THE PRESSURE GRADIENT WILL INCREASE IN THE AFTERNOON BETWEEN THE
HIGH PRES AND LOWER PRESSURE OVER MOST OF THE GULF OF MEXICO. AS
A RESULT...EXPECT INCREASING SOUTHERLY WINDS ON THE WESTERN
PERIPHERY OF THE RIDGE...PARTICULARLY BETWEEN THE EAST COAST OF
FLORIDA AND 77W. MODERATE TO LOCALLY FRESH EASTERLY WINDS ARE
NOTED ACROSS THE SOUTHERN PERIPHERY OF THE RIDGE. PATCHES OF LOW
LEVEL MOISTURE ARE ALSO OBSERVED UNDER THE INFLUENCE OF THE
RIDGE. FARTHER EAST...A WEAKENING STATIONARY FRONT ENTERS THE
FORECAST AREA NEAR 31N37W AND EXTENDS TO 26N41W. THIS FRONT IS
GENERATING SOME SHOWER ACTIVITY PARTICULARLY N OF 26N E OF THE
FRONT TO NEAR 33W. A RIDGE DOMINATES THE REMAINDER OF ATLANTIC
WHILE A TROUGH EXTENDS FROM THE WESTERN CANARY ISLANDS TO THE
WEST COAST OF AFRICA NEAR 23N16W. THE CURRENT THE MID TO UPPER-
LEVEL MOISTURE STREAMING NE ACROSS THE GULF OF MEXICO AND
FLORIDA REACHES THE SW N ATLC...AND IS RIDING ON THE NORTHERN
PERIPHERY OF THE RIDGE THAT DOMINATES THE CARIBBEAN SEA.
ALOFT...A RIDGE/TROUGH/RIDGE PATTERN IS NOTED WITH AN UPPER-
LEVEL LOW SPINNING BETWEEN THE MADEIRA AND CANARY ISLANDS.
LOOKING AHEAD...A STRONG COLD FRONT WILL MOVE INTO THE SW N ATLC
WED NIGHT. THE FRONT WILL WEAKEN AS IT QUICKLY REACHES FROM
31N70W TO THE CENTRAL BAHAMAS BY THU EVENING...THEN FROM 30N65W
TO THE CENTRAL BAHAMAS FRI MORNING. FRESH TO STRONG NW WINDS AND
BUILDING SEAS ARE EXPECTED BEHIND THE FRONT WED NIGHT AND THU.


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

$$
GR



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