[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 011118
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SUN MAR 01 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.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 7N11W 3N18W CROSSING THE EQUATOR
NEAR 24W EXTENDING TO 2S36W INTO NE BRAZIL NEAR 4S44W. SCATTERED
MODERATE CONVECTION IS S OF 2N BETWEEN 12W-14W. SCATTERED
MODERATE CONVECTION IS ALSO S OF 2N BETWEEN 19W-26W. SIMILAR
CONVECTION IS S OF 1N BETWEEN 31W-33W.

...DISCUSSION...

GULF OF MEXICO...
A DEEP LAYER TROUGH OVER THE E CONUS EXTENDS SOUTHWARD INTO THE
GULF REGION. THIS DEEP LAYER TROUGH IS ASSOCIATED WITH A SURFACE
COLD FRONT THAT EXTENDS FROM THE FLORIDA PANHANDLE NEAR 30N84W
TO 24N90W TO THE COAST OF MEXICO NEAR 18N95W. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS AND ISOLATED
THUNDERSTORMS ALONG AND WITHIN 90 NM SE OF THE COLD FRONT. IN
THE WAKE OF THE COLD FRONT...INCREASED NORTHERLY WINDS ARE
OCCURRING OVER THE GULF...WITH A GALE WARNING IN EFFECT FOR
PORTIONS OF THE SW...MIDDLE...AND E GULF. ALSO...RELATIVELY
COOLER AND DRIER CONDITIONS ARE PRESENT TO THE N OF THE
FRONT...WITH GENERALLY FAIR WEATHER ACROSS THE NW GULF WHERE
STABLE ATMOSPHERIC CONDITIONS ARE PRESENT. THE COLD FRONT IS
FORECAST TO MOVE E OF THE GULF REGION TONIGHT. 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 01/1200 UTC AND STORM FORCE WINDS IN
THE E PACIFIC REGION BEGINNING AT 02/0600 UTC.

CARIBBEAN SEA...
GENERALLY FAIR WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF
THE CARIBBEAN REGION...WHERE SUBSIDENCE IS BEING SUPPORTED BY
CONFLUENCE IN WESTERLY FLOW ALOFT. PATCHES OF LOW LEVEL MOISTURE
CONTINUE TO BE ADVECTED WESTWARD ACROSS THE CARIBBEAN...WITH
SCATTERED SHOWERS EMBEDDED WITHIN THESE PATCHES OF LOW LEVEL
MOISTURE. THE GREATEST CONCENTRATION OF THESE SHOWERS IS FROM
18N-21N BETWEEN 80W-86W. ALSO...INCREASED UPPER LEVEL MOISTURE
IS STREAMING NORTHEASTWARD ACROSS PORTIONS OF THE E CARIBBEAN.
THE AFOREMENTIONED COLD FRONT CURRENTLY OVER THE GULF OF MEXICO
IS FORECAST TO MOVE INTO THE NW CARIBBEAN LATER TODAY...WITH
RELATIVELY COOLER AND DRIER CONDITIONS IN THE WAKE OF THE FRONT.

ATLANTIC OCEAN...
THE AFOREMENTIONED DEEP LAYER TROUGH OVER THE E CONUS IS
ASSOCIATED WITH THE AFOREMENTIONED SURFACE COLD FRONT OVER THE
GULF OF MEXICO. THIS COLD FRONT EXTENDS NORTHEASTWARD INTO THE
SE CONUS...AND IS FORECAST TO ENTER THE FAR NW WATERS OF THE SW
NORTH ATLC THIS MORNING. RELATIVELY COOLER AND DRIER CONDITIONS
ARE PRESENT IN THE WAKE OF THE FRONT. FARTHER TO THE E...A DEEP
LAYER TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A SURFACE
TROUGH OVER THE CENTRAL ATLC THAT EXTENDS FROM 22N59W TO 25N56W
TO 28N53W...A SURFACE STATIONARY FRONT ALSO OVER THE CENTRAL
ATLC THAT EXTENDS FROM 28N53W TO 30N43W TO 31N27W...AND A
SURFACE COLD FRONT ALSO OVER THE CENTRAL ATLC THAT EXTENDS FROM
31N27W TO 32N21W TO NE OF THE DISCUSSION AREA. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 120 NM EITHER
SIDE OF THE SURFACE FRONTS AND SURFACE TROUGH. THIS ACTIVITY IS
BEING ENHANCED BY ATMOSPHERIC LIFT ASSOCIATED WITH UPPER LEVEL
DIVERGENCE IN THE NE QUADRANT OF A 110-120 KT UPPER LEVEL JET
MAXIMUM OVER THE CENTRAL ATLC. COMPUTER MODEL GUIDANCE SUGGESTS
THAT THIS ATMOSPHERIC LIFT IS EXPECTED TO INTERACT WITH THE
SURFACE FRONTS OVER THE CENTRAL ATLC TO RESULT IN THE
DEVELOPMENT OF A SURFACE LOW OVER THE CENTRAL ATLC DURING THE
NEXT DAY...WHICH IS EXPECTED TO BE A 1015 MB SURFACE LOW NEAR
30N42W AT 02/0600 UTC. ALSO...ACROSS LOCATIONS IN THE CENTRAL
AND E ATLC THAT ARE SE OF THE SURFACE FRONTS AND SURFACE
TROUGH...SUBSIDENCE ASSOCIATED WITH A SURFACE RIDGE IS
SUPPORTING FAIR WEATHER CONDITIONS. THIS SURFACE RIDGE EXTENDS
SOUTHWARD FROM A 1024 MB SURFACE HIGH NEAR 28N35W. THIS SURFACE
HIGH IS FORECAST TO HAVE DISSIPATED BY 02/0600 UTC. ACROSS THE
TROPICAL ATLC...AN UPPER LEVEL RIDGE IS S OF 12N E OF 49W WITH
AN UPPER LEVEL HIGH NEAR 2N21W. UPPER LEVEL DIVERGENCE
ASSOCIATED WITH THIS UPPER LEVEL RIDGE AND UPPER LEVEL HIGH IS
ENHANCING THE CONVECTION ASSOCIATED WITH THE ITCZ.

$$
COHEN




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