[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230550
TWDAT

TROPICAL WEATHER DISCUSSION
NWS NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST SUN DEC 23 2012

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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0515 UTC.

...ITCZ/MONSOON TROUGH...

THE MONSOON TROUGH EXTENDS ACROSS AFRICA INTO THE E TROPICAL
ATLC NEAR 6N10W TO 4N12W WHERE THE ITCZ CONTINUES ALONG 4N18W
5N36W TO SOUTH AMERICA NEAR 4N51W. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE FROM 1N-6N BETWEEN
15W-23W. CLUSTERS OF SCATTERED MODERATE CONVECTION ARE WITHIN 90
NM N OF THE ITCZ BETWEEN 23W-27W...FROM 2N-4N BETWEEN 29W-36W...
AND FROM 5N-7N BETWEEN 37W-44W.

...DISCUSSION...

GULF OF MEXICO...
A BROAD UPPER RIDGE EXTENDS FROM THE E PACIFIC REGION ACROSS
MEXICO TO OVER THE CENTRAL CONUS COVERING MOST OF THE GULF OF
MEXICO AND DEEPENING THE BROAD UPPER TROUGH THAT COVERS THE W
ATLC INTO THE CARIBBEAN. A SURFACE RIDGE COVERS THE GULF
ANCHORED BY A 1026 MB HIGH ALONG THE N GULF COAST NEAR MOBILE
ALABAMA. THE SOUTHERLY RETURN FLOW OVER THE W GULF IS GENERATING
ISOLATED SHOWERS WITHIN 90 NM ALONG THE W GULF COAST FROM E OF
VERACRUZ MEXICO TO VERMILION BAY LOUISIANA. THE REMAINDER OF THE
GULF IS UNDER CLEAR SKIES AGAIN TONIGHT. HIGH PRESSURE WILL
SHIFT E THROUGH SUN. A COLD FRONT WILL APPROACH THE N GULF MON
THEN STALL AS A STATIONARY FRONT N OF 28N MON NIGHT AND TUE. A
STRONGER COLD FRONT WILL RACE SE ACROSS THE REGION TUE AND WED.

CARIBBEAN SEA...
THE BROAD UPPER TROUGH OVER THE W ATLC EXTENDS S OVER THE W
CARIBBEAN W OF 65W SUPPORTING A COLD FRONT IN THE W ATLC ACROSS
PORTIONS OF HAITI TO NEAR 19N74W WHERE A SHEAR LINE CONTINUES TO
INLAND OVER CENTRAL NICARAGUA NEAR 13N84W. ISOLATED SHOWERS ARE
POSSIBLE WITHIN 200 NM E OF THE SHEAR LINE. A BROAD UPPER RIDGE
AXIS IS E OF THE LESSER ANTILLES TO OVER THE CENTRAL ATLC
COVERING THE REMAINDER OF THE E CARIBBEAN. SCATTERED SHOWERS/
ISOLATED THUNDERSTORMS OVER THE E CARIBBEAN FROM VENEZUELA TO
OVER THE GREATER ANTILLES BETWEEN 63W-70W WITH SCATTERED SHOWERS
S OF 15N E OF 74W TO THE WINDWARD ISLANDS. STRONG SUBSIDENCE AND
DRY STABLE AIR ALOFT COVER THE CARIBBEAN W OF 70W LEAVING THE
AREA W OF THE SHEAR LINE UNDER CLEAR SKIES TONIGHT. SHEAR LINE
WILL MOVE E FROM THE MONA PASSAGE TO PANAMA BY SUN NIGHT. HIGH
PRESSURE BUILDING OVER THE W ATLC WILL SUPPORT FRESH TO STRONG
TRADE WINDS ACROSS THE CENTRAL CARIBBEAN THROUGH THE MIDDLE OF
NEXT WEEK. ANOTHER FRONT WILL MOVE INTO THE NW CARIBBEAN NEXT
THU.

ATLANTIC OCEAN...
THE BROAD UPPER TROUGH COVERS THE W ATLC W OF 60W SUPPORTING A
COLD FRONT THAT ENTERS THE W ATLC NEAR 32N59W ALONG 25N65W TO
OVER PORTIONS OF HAITI TO NEAR 19N74W WHERE IT CONTINUES AS A
SHEAR LINE OVER THE CARIBBEAN. ISOLATED SHOWERS ARE POSSIBLE
WITHIN 90 NM W OF THE FRONT. THE SURFACE RIDGE OVER THE GULF OF
MEXICO CONTINUES TO BUILD E OVER THE W ATLC W OF THE FRONT. THE
WEAK SURFACE RIDGE IS OVER THE REMAINDER OF THE W INTO THE
CENTRAL ATLC AND IS ANCHORED BY A 1018 MB HIGH NEAR 24N59W. AN
UPPER TROUGH COVERS THE E ATLC N OF 20N E OF 40W SUPPORTING
ANOTHER COLD FRONT THAT ENTERS THE DISCUSSION AREA NEAR 32N28W
CONTINUING ALONG 25N32W TO 19N43W. A SURFACE TROUGH TRAILS THE
FRONT EXTENDING FROM 30N32W ALONG 27N36W TO 25N43W. SCATTERED
SHOWERS/ISOLATED THUNDERSTORMS ARE WITHIN 200 NM E OF THE FRONT
N OF 23N. W ATLC COLD FRONT WILL WEAKEN INTO A SHEAR LINE N OF
THE LEEWARD ISLANDS SUN AND SUN NIGHT. HIGH PRESSURE BUILDING
BEHIND THE FRONT WILL SHIFT E ALONG 30N. A STRONG COLD FRONT IS
EXPECTED MOVE OFF THE NE FLORIDA COAST LATE TUE REACHING FROM
31N71W TO THE STRAITS OF FLORIDA BY LATE WED AND FROM 31N65W TO
CENTRAL CUBA BY LATE THU.

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

$$
PAW





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