[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221110
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST MON DEC 22 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 STRONG COLD FRONT IS FORECAST BY THE COMPUTER MODELS TO
APPROACH THE TEXAS COAST EARLY TUE AND EMERGE INTO THE NW GULF
TUE AFTERNOON. STRONG TO MINIMAL GALE FORCE NORTHERLY WINDS ARE
EXPECTED BEHIND THE FRONT ACROSS THE WESTERN GULF WATERS TUE
NIGHT AND WED. A GALE WARNING IS ALREADY IN EFFECT FOR THE
WESTERN GULF. THE FRONT WILL EXTEND FROM SE LOUISIANA TO NEAR
TAMPICO MEXICO TUE EVENING...FROM THE FLORIDA PANHANDLE TO NEAR
VERACRUZ MEXICO WED MORNING...FROM THE TAMPA BAY AREA TO THE
EASTERN BAY OF CAMPECHE WED EVENING AND WILL BE EAST OF AREA WED
NIGHT INTO THU MORNING WHEN IS FORECAST 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.

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

THE MONSOON TROUGH CROSSES THE WEST COAST OF AFRICA NEAR 08N13W
TO 06N16W WHERE THE ITCZ BEGINS AND CONTINUES TO 05N30W TO
06N40W TO THE COAST OF SOUTH AMERICA AT 03N51W. SCATTERED TO
NUMEROUS MODERATE CONVECTION IS NOTED WITHIN 150 NM N...AND 45
NM S OF THE ITCZ AXIS BETWEEN 22W AND 46W.

...DISCUSSION...

GULF OF MEXICO...

AS OF 0900 UTC...A QUASI-STATIONARY FRONT EXTENDS FROM NORTHERN
FLORIDA NEAR 29N83W TO THE CENTRAL GULF OF MEXICO NEAR 27N90W TO
A WEAK 1011 MB LOW PRES LOCATED NEAR 24N96W. THIS LOW PRES IS
ANALYZED BASED ON AN ASCAT PASS THAT SHOWS THE CYCLONIC
CIRCULATION ASSOCIATED WITH THIS FEATURE. A TROUGH EXTENDS FROM
THE LOW CENTER TO NEAR 20N97W. RADAR IMAGERY SHOWS SCATTERED
SHOWERS WITH EMBEDDED TSTMS OVER NORTH FLORIDA AND ACROSS THE
FAR NORTHERN GULF WATERS IN A BAND THAT EXTENDS FROM SE
LOUISIANA TO THE FLORIDA PANHANDLE. GENTLE TO MODERATE WINDS ARE
NOTED PER SCATTEROMETER AND SURFACE DATA NORTH OF THE FRONT.
MODERATE TO LOCALLY FRESH SOUTHERLY WINDS ARE SEEN S OF THE
FRONT AND E OF 87W. THIS FRONT IS FORECAST TO DISSIPATE TODAY
ACROSS THE GULF REGION WHILE A BAND OF SHOWERS AND TSTMS WILL
PERSIST OVER NORTHERN FLORIDA. A SURFACE TROUGH IS AHEAD OF THE
FRONT OVER THE SE GULF AND EXTENDS FROM 26N87W TO 23N87.5W.
CONVECTION HAS DIMINISHED AHEAD OF THE TROUGH AND CURRENTLY ONLY
A FEW SHOWERS ARE BETWEEN THE TROUGH AXIS AND THE W COAST OF
FLORIDA. SOUTHERLY RETURN FLOW WILL INTENSIFY LATE TODAY AHEAD
OF A STRONG COLD FRONT EXPECTED TO ENTER THE NW GULF ON TUE. SEE
SPECIAL FEATURE FOR DETAILS. IN THE UPPER LEVELS...SW FLOW
DOMINATES THE ENTIRE GULF AHEAD OF A LONG-WAVE TROUGH THAT
CROSSES EASTERN TEXAS AND NE MEXICO. THESE WINDS ARE
TRANSPORTING ABUNDANT MID TO UPPER LEVEL MOISTURE ACROSS THE
GULF REGION AND FLORIDA INTO THE WESTERN ATLC.

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. GENTLE TO MODERATE E TO SE WINDS ARE NOTED
OVER THE WESTERN CARIBBEAN. SHALLOW MOISTURE EMBEDDED IN THE
TRADE WIND FLOW IS SEEN ON SATELLITE IMAGERY MAINLY SOUTH OF
HISPANIOLA...OVER JAMAICA AND ACROSS THE WESTERN CARIBBEAN W OF
83W. FRESH TO STRONG TRADE WINDS ARE EXPECTED TO PERSIST OVER
THE CENTRAL CARIBBEAN THROUGH THE WEEK. A STRONG COLD FRONT IS
FORECAST TO MOVE INTO THE NW CARIBBEAN WED NIGHT...EXTEND FROM
WESTERN CUBA TO THE GULF OF HONDURAS THU...THEN STALL FROM
CENTRAL CUBA TO THE GULF OF HONDURAS THU NIGHT. STRONG NW TO N
WINDS AND BUILDING SEAS ARE EXPECTED W OF THE FRONT. IN THE
UPPER LEVELS...A RIDGE WITH AXIS ALONG 75W DOMINATES THE WEST
AND CENTRAL CARIBBEAN WHILE A ZONAL FLOW IS OVER THE E
CARIBBEAN. STRONG SUBSIDENCE IS OVER MOST OF THE BASIN E OF 80W.
MID TO UPPER LEVEL MOISTURE IS ON INCREASE OVER THE 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...

AS OF 0600 UTC...A 1011 MB LOW PRES IS CENTERED OFF THE COAST OF
GEORGIA NEAR 31N78W. A QUASI-STATIONARY FRONT EXTENDS SW FROM
THE LOW TO NORTHERN FLORIDA THEN CONTINUES ACROSS THE GULF OF
MEXICO. A WARM FRONT EXTENDS EASTWARD FROM THE LOW TO 31N70W.
SCATTERED SHOWERS AND TSTMS ARE ASSOCIATED WITH THE LOW AND
FRONT. THE LOW IS FORECAST TO MOVE NE AND AWAY FROM THE FORECAST
REGION IN ABOUT 12-24 HOURS WHILE THE FRONT WILL MOVE N OF THE
AREA TODAY. A 1023 MB HIGH IS FARTHER E CENTERED JUST N OF
BERMUDA. THIS HIGH IS FORECAST TO MOVE EASTWARD REACHING A
POSITION NEAR 32N61W BY THIS EVENING. CURRENTLY...THIS SYSTEM
EXTENDS A RIDGE ROUGHLY N OF 20N BETWEEN 45W AND 70W. MAINLY
LIGHT WINDS AND PATCHES OF LOW LEVEL MOISTURE ARE NOTED UNDER
THE INFLUENCE OF THE RIDGE THAT WILL EXTEND TOWARD FLORIDA
TONIGHT. THE TAIL END OF A COLD FRONT IS OVER THE CENTRAL
ATLANTIC STRETCHING FROM 31N38W TO 26N44W. SCATTERED SHOWERS ARE
WITHIN 90 NM E OF THE FRONT N OF 28N. A 1030 MB HIGH IS OVER THE
E ATLANTIC CENTERED NEAR 43N15W WITH SURFACE RIDGING EXTENDING S
OF THE CANARY ISLANDS AND SW TO NEAR 26N36. MODERATE TO FRESH
TRADE WINDS ARE OBSERVED PER SCATTEROMETER DATA ACROSS THE
TROPICAL ATLANTIC. IN THE UPPER LEVELS...AN UPPER LEVEL TROUGH
IS OVER THE CENTRAL ATLANTIC SUPPORTING THE CENTRAL ATLANTIC
COLD FRONT. A UPPER LEVEL LOW IS SPINNING OVER THE CANARY
ISLANDS NEAR 28N18W. A BAND OF TRANSVERSE HIGH CLOUDS EXTENDS
FROM THE GUYANAS ALL THE WAY E-NE TO WESTERN AFRICA ASSOCIATED
WITH STRONG UPPER-LEVEL SW AND W WINDS. LOOKING AHEAD...
SOUTHERLY WINDS WILL INCREASE OVER THE SW N ATLANTIC NEAR EAST
FLORIDA TUE NIGHT AND WED AHEAD OF A STRONG COLD FRONT MOVING
INTO THE ATLANTIC REGION WED NIGHT. THE FRONT WILL REACH FROM
31N77W TO W CUBA THU...FROM 31N70W TO CENTRAL CUBA THU
NIGHT...AND FROM 30N65W TO CENTRAL CUBA FRI NIGHT. FRESH TO
STRONG NW WINDS AND BUILDING SEAS ARE EXPECTED BEHIND THE FRONT.

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

$$
GR


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