[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281741
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM EST SAT NOV 28 2009

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...METEOROLOGICAL ANALYSIS...WEATHER
OBSERVATIONS...AND RADAR.

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

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 9N13W 5N30W 3N51W. WIDELY
SCATTERED MODERATE CONVECTION IS FROM 3N-7N BETWEEN 9W-21W.
SCATTERED MODERATE CONVECTION IS FROM 1N-7N BETWEEN 25W-38W.

...DISCUSSION...

GULF OF MEXICO...
A 1022 MB SURFACE HIGH PRESSURE CENTERED OVER THE WESTERN
FLORIDA PANHANDLE CONTINUES TO STRETCH A RIDGE ACROSS THE
FLORIDA PENINSULA AND NW BAHAMAS TO THE SE AND ANOTHER RIDGE
S-SW TO SOUTHERN MEXICO AND THE BAY OF CAMPECHE. THE HIGH
PRESSURE AREAS ARE BRINGING GENERALLY FAIR WEATHER ACROSS MUCH
OF THE BASIN. HOWEVER...MOIST SWLY AND MID-LEVEL DIFFLUENT FLOW
ALOFT BETWEEN AN UPPER LEVEL SHORTWAVE TROUGH OVER EASTERN TEXAS
AND AN UPPER LEVEL RIDGE EXTENDING FROM THE WESTERN CARIBBEAN
ACROSS THE SE GULF ARE GENERATING A FEW ISOLATED SHOWERS ACROSS
LOUISIANA AND THE NW GULF N OF A LINE FROM NEW ORLEANS TO TUXPAN
MEXICO. AS THE SURFACE HIGH SHIFTS GRADUALLY EASTWARD INTO THE W
ATLC...SOUTHERLY RETURN FLOW IS FORECAST TO INCREASE ACROSS THE
WESTERN GULF WATERS THROUGH SUNDAY AHEAD OF THE NEXT COLD FRONT
TO ENTER THE NW GULF EARLY MONDAY.

CARIBBEAN SEA...
AS OF 1500 UTC...A STATIONARY FRONT EXTENDS FROM THE TURKS AND
CAICOS ISLANDS IN THE W ATLC ACROSS EASTERN CUBA AND INTO THE NW
CARIBBEAN NEAR 20N78W TO 18N84W. SCATTERED SHOWERS ARE OCCURRING
WITHIN 120 NM EITHER SIDE OF THE FRONT. THIS SHOWER ACTIVITY
LINGERS SW FROM THE TAIL END OF THE FRONT INTO THE GULF OF
HONDURAS AND ACROSS PORTIONS OF CENTRAL AMERICA INCLUDING...
HONDURAS...BELIZE...AND GUATEMALA. E-NE TRADE WINDS UP TO 25 KT
ARE OBSERVED E OF THE FRONTAL BOUNDARY WITH SURFACE CONVERGENCE
AND CLOSE PROXIMITY OF THE E PACIFIC ITCZ AXIS ALONG 7N
GENERATING SCATTERED SHOWERS AND ISOLATED TSTMS OVER THE SW
CARIBBEAN S OF 10N AND PORTIONS OF PANAMA AND COSTA RICA.
FURTHER ENHANCING THIS CONVECTION IS THE PRESENCE OF AN UPPER
LEVEL RIDGE AND DIFFLUENT FLOW ALOFT OVER COLOMBIA AND THE SW
CARIBBEAN. THE REMAINDER OF THE CARIBBEAN IS EXPERIENCING
GENERALLY FAIR WEATHER AND CLEAR SKIES UNDER THE INFLUENCE OF
DRY AND SUBSIDENT AIR ALOFT ASSOCIATED WITH THE AFOREMENTIONED
UPPER LEVEL ANTICYCLONIC FLOW COVERING THE ENTIRE BASIN.

ATLANTIC OCEAN...
A COLD FRONT EXTENDS ACROSS THE W ATLC ENTERING THE DISCUSSION
AREA NEAR 32N57W CONTINUING SW ALONG 25N65W TO THE TURKS AND
CAICOS ISLANDS NEAR 22N71W THEN STATIONARY TO EASTERN CUBA AND
INTO THE NW CARIBBEAN. A PRE-FRONTAL SURFACE TROUGH IS ANALYZED
E OF THE FRONT FROM 25N64W TO 20N69W. SCATTERED SHOWERS ARE
WITHIN 200 NM OF THE COLD FRONT N OF 25N AND WITHIN 60 NM EITHER
SIDE OF THE FRONT AND SURFACE TROUGH S OF 25N. THE FRONT IS
SUPPORTED ALOFT BY AN UPPER LEVEL TROUGH OVER THE WESTERN NORTH
ATLC WITH AXIS EXTENDING FROM AN UPPER LEVEL LOW OVER NOVA
SCOTIA TO NEAR 30N60W. UPPER LEVEL DIFFLUENT FLOW BETWEEN THIS
UPPER LEVEL TROUGH AND AN UPPER LEVEL RIDGE EXTENDING FROM THE
EASTERN CARIBBEAN TO NEAR 33N51W IS SUPPORTING THE CONVECTION.
FARTHER EAST ACROSS THE CENTRAL ATLC...A NARROW UPPER LEVEL
TROUGH WITH AXIS ALONG 48W IS SUPPORTING SCATTERED SHOWERS AND
TSTMS FROM 18N-28N BETWEEN 43W-48W. A SURFACE TROUGH IS ANALYZED
E OF THE LESSER ANTILLES EXTENDING FROM 11N56W TO 18N54W.
POSSIBLE SCATTERED SHOWERS ARE OCCURRING WITHIN 120 NM EITHER
SIDE OF THE SURFACE TROUGH. THE REMAINDER OF THE E ATLC IS
DOMINATED BY A BROAD SURFACE RIDGE ANCHORED BY A 1029 MB HIGH
CENTERED N OF THE DISCUSSION AREA NEAR 37N31W. HOWEVER...AN
UPPER LEVEL SHORTWAVE TROUGH IS NEAR THE MADEIRA ISLANDS AND
SUPPORTS A COLD FRONT THAT CLIPS THE FAR NE PORTION OF THE ATLC
EXTENDING ALONG 31N BETWEEN 15W-22W. ISOLATED SHOWERS ARE WITHIN
30 NM OF THE COLD FRONT.

$$
HUFFMAN





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