[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 110515
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...THE ITCZ...

ITCZ IS CENTERED ALONG 7N10W 3N20W 2N31W 1N42W AND INTO NE
BRAZIL NEAR 1S52W. SCATTERED MODERATE CONVECTION IS FROM 4N-6N
BETWEEN 21W-25W. SCATTERED MODERATE CONVECTION IS ALSO FROM
3N-7N 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
S LOUISIANA NEAR 30N91W TO 27N95W TO 25N98W. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER
SIDE OF THE COLD FRONT. THIS ACTIVITY IS BEING ENHANCED IN THE
SW QUADRANT OF AN UPPER LEVEL JET MAXIMUM OVER THE E CONUS. THE
COLD FRONT IS FORECAST TO MOVE SOUTHWARD ACROSS THE GULF FOR THE
REMAINDER OF THIS WEEKEND INTO EARLY NEXT WEEK AND IS FORECAST
TO REACH THE YUCATAN CHANNEL TUESDAY AFTERNOON. INCREASED
NORTHERLY WINDS...AS WELL AS COOLER AND DRIER CONDITIONS...ARE
PRESENT IN THE WAKE OF THE FRONT. GALE CONDITIONS ARE EXPECTED
ACROSS PORTIONS OF THE SW GULF FOR SUNDAY THROUGH MONDAY. AHEAD
OF THE FRONT...INCLUDING MUCH OF THE SE GULF...THE RETURN FLOW
AROUND A 1027 MB SURFACE HIGH OVER THE W ATLC NEAR 33N67W IS
RESULTING IN SOUTHERLY WINDS OF 10 TO 20 KT. DEEP LAYER DRY AIR
IS INHIBITING DEEP CONVECTION ACROSS THE SE GULF.

CARIBBEAN SEA...
AN UPPER RIDGE IS PRESENT ACROSS THE CARIBBEAN REGION...WITH THE
UPPER RIDGE AXIS EXTENDING FROM N VENEZUELA NEAR 9N65W TO
15N73W TO 20N82W. 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 SCATTERED
SHOWERS FROM 14N-18N BETWEEN 79W-85W. FRESH TO STRONG TRADE
WINDS ARE PRESENT ACROSS THE CARIBBEAN SEA. THESE TRADE WINDS
ARE FORECAST TO CONTINUE DURING THE NEXT FEW DAYS AS THE 1027 MB
SURFACE HIGH IN THE W ATLC NEAR 33N67W MOVES EAST-NORTHEASTWARD.
THE STRONGEST WINDS...UP TO 30 KT...ARE NEAR THE COAST OF
COLOMBIA. THE COLD FRONT CURRENTLY IN THE GULF OF MEXICO IS
FORECAST TO REACH THE YUCATAN CHANNEL TUESDAY AFTERNOON.

ATLANTIC OCEAN...
A DEEP TROUGH IS PRESENT ACROSS THE W ATLC N OF THE DISCUSSION
AREA. THIS DEEP TROUGH IS ASSOCIATED WITH A SURFACE STATIONARY
FRONT THAT EXTENDS FROM 23N66W TO 27N53W TO 31N56W AND A SURFACE
COLD FRONT THAT EXTENDS FROM 31N58W TO 32N44W TO NE OF THE
DISCUSSION AREA. LOW LEVEL CONVERGENCE IS SUPPORTING SCATTERED
SHOWERS WITHIN 90 NM EITHER SIDE OF THE SURFACE STATIONARY FRONT
AND SURFACE COLD 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 33N67W. FARTHER TO THE
E...AN UPPER TROUGH IS PRESENT WITH AN AXIS EXTENDING FROM
15N35W TO 27N40W TO 32N41W. ATMOSPHERIC INSTABILITY ASSOCIATED
WITH THIS UPPER TROUGH IS RESULTING IN SCATTERED SHOWERS FROM
16N-27N BETWEEN 25W-36W. THIS ACTIVITY IS BEING ENHANCED BY
ATMOSPHERIC LIFT ASSOCIATED WITH DIFFLUENCE IN SOUTHWESTERLY
FLOW ALOFT TO THE E OF THIS UPPER TROUGH AXIS. TO THE E...
SUBSIDENCE IS RESULTING IN GENERALLY FAIR WEATHER IN THE
VICINITY OF A 1027 MB SURFACE HIGH CENTERED NEAR 33N28W. ACROSS
THE TROPICAL ATLC...AN UPPER RIDGE AXIS EXTENDS FROM 8N12W TO
6N21W TO 3N34W. UPPER LEVEL DIVERGENCE NEAR THIS UPPER RIDGE IS
ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN


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