[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 111106
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN JAN 11 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 5N9W 3N21W 2N32W 2N41W AND INTO NE
BRAZIL NEAR 1S53W. SCATTERED MODERATE CONVECTION IS FROM 1N-3N
BETWEEN 15W-21W. SCATTERED MODERATE CONVECTION IS ALSO FROM
3N-5N BETWEEN 28W-34W.

...DISCUSSION...

GULF OF MEXICO...
SOUTHWESTERLY FLOW ALOFT CONTINUES TO INCREASE ACROSS THE GULF
REGION AS A DEEP TROUGH OVER THE CENTRAL CONUS MOVES EASTWARD. A
SURFACE COLD FRONT ASSOCIATED WITH THIS DEEP TROUGH EXTENDS FROM
THE W FLORIDA PANHANDLE NEAR 30N87W TO 26N94W TO THE E COAST OF
MEXICO NEAR 21N97W AND EXTENDS NORTHWESTWARD ACROSS MEXICO. LOW
LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND WITHIN 90 NM AHEAD OF THE COLD FRONT.
THIS ACTIVITY IS BEING ENHANCED IN THE SW QUADRANT OF AN UPPER
LEVEL JET MAXIMUM LOCATED OVER THE E CONUS. THE COLD FRONT IS
FORECAST TO CONTINUE MOVING SOUTHWARD ACROSS THE GULF AND REACH
THE YUCATAN PENINSULA MONDAY AFTERNOON. INCREASED NORTHERLY
WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE PRESENT IN
THE WAKE OF THE FRONT. GALE CONDITIONS ARE FORECAST ACROSS
PORTIONS OF THE SW GULF FOR THIS AFTERNOON AND TONIGHT. AHEAD OF
THE FRONT...INCLUDING MUCH OF THE SE GULF...THE RETURN FLOW
AROUND A 1027 MB SURFACE HIGH OVER THE W ATLC NEAR 33N63W IS
RESULTING IN SOUTHERLY WINDS OF 10 TO 15 KT. DEEP LAYER DRY AIR
IS INHIBITING DEEP CONVECTION ACROSS THE SE GULF.
ADDITIONALLY...STRONG N TO NE SURFACE WINDS ARE FORECAST TO BLOW
THROUGH THE ISTHMUS OF TEHUANTEPEC RESULTING IN GALE FORCE WINDS
IN THE E PACIFIC REGION BEGINNING AT 12/0000 UTC.

CARIBBEAN SEA...
AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN REGION...WITH THE
UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 10N65W TO
17N77W TO 21N84W. SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS
ASSOCIATED WITH THIS UPPER RIDGE ARE RESULTING IN GENERALLY FAIR
WEATHER ACROSS MUCH OF THE CARIBBEAN SEA. HOWEVER...ACROSS THE W
CARIBBEAN...DEEP MOISTURE IS BEING TRANSPORTED NORTHWARD TO THE
W OF THE UPPER RIDGE AXIS...WHICH IS RESULTING IN ISOLATED
SHOWERS S OF 18N W OF 81W. MODERATE TO STRONG EASTERLY TRADE
WINDS ARE PRESENT ACROSS MUCH OF THE CARIBBEAN SEA. THESE TRADE
WINDS ARE FORECAST TO CONTINUE THROUGH TUESDAY AS THE 1027 MB
SURFACE HIGH IN THE W ATLC NEAR 33N63W MOVES EAST-NORTHEASTWARD.
THE STRONGEST WINDS...UP TO 30 KT...ARE NEAR THE COAST OF
COLOMBIA. A COLD FRONT IS FORECAST TO MOVE ACROSS THE YUCATAN
CHANNEL AND INTO THE NW CARIBBEAN WEDNESDAY AND THURSDAY.

ATLANTIC OCEAN...
A DEEP TROUGH IS PRESENT ACROSS THE W ATLC N OF THE DISCUSSION
AREA. THIS DEEP TROUGH IS ASSOCIATED WITH A SURFACE COLD FRONT
THAT EXTENDS FROM NE OF THE DISCUSSION AREA TO 32N44W TO 27N51W
TO 24N59W AND A DISSIPATING SURFACE STATIONARY FRONT THAT
EXTENDS FROM 24N59W TO 24N64W TO 23N68W. LOW LEVEL CONVERGENCE
IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER SIDE OF THE
SURFACE COLD FRONT AND ISOLATED SHOWERS WITHIN 30 NM EITHER SIDE
OF THE DISSIPATING SURFACE STATIONARY FRONT. TO THE W OF THESE
FRONTS...DEEP LAYER DRY AIR AND SUBSIDENCE ARE RESULTING IN
GENERALLY FAIR WEATHER ACROSS MUCH OF THE SW ATLC. THIS
SUBSIDENCE IS BEING ENHANCED AROUND THE 1027 MB SURFACE HIGH
NEAR 33N63W. ALSO...A SURFACE COLD FRONT IS FORECAST TO MOVE OFF
THE SE CONUS INTO THE SW ATLC TONIGHT...WHICH WILL MERGE WITH A
REINFORCING SURFACE COLD FRONT ON TUESDAY THAT IS ALSO FORECAST
TO MOVE OFF THE SE CONUS INTO THE SW ATLC. GALE CONDITIONS ARE
EXPECTED N OF 29N WITHIN 480 NM E OF THE COLD FRONT FOR TUESDAY
AND WEDNESDAY. FARTHER TO THE E...AN UPPER TROUGH IS PRESENT
WITH AN AXIS EXTENDING FROM 15N34W TO 26N39W TO 31N40W.
ATMOSPHERIC INSTABILITY ASSOCIATED WITH THIS UPPER TROUGH IS
RESULTING IN SCATTERED SHOWERS FROM 18N-29N BETWEEN 23W-35W.
THIS ACTIVITY IS BEING ENHANCED BY ATMOSPHERIC LIFT ASSOCIATED
WITH DIFFLUENCE IN SOUTHWESTERLY FLOW ALOFT TO THE E OF THIS
UPPER TROUGH AXIS. FARTHER TO THE E...SUBSIDENCE IS RESULTING IN
GENERALLY FAIR WEATHER IN THE VICINITY OF A 1025 MB SURFACE HIGH
CENTERED NEAR 29N38W AND A 1026 MB SURFACE HIGH CENTERED NEAR
33N22W. ACROSS THE TROPICAL ATLC...AN UPPER RIDGE AXIS EXTENDS
FROM 7N10W TO 5N23W TO 3N35W. UPPER LEVEL DIVERGENCE NEAR THIS
UPPER RIDGE IS ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN


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