[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 270559
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 AM EST FRI FEB 27 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
0515 UTC.

...ITCZ...

THE ITCZ AXIS IS CENTERED ALONG 5N8W 2N11W CROSSING THE EQUATOR
NEAR 14W EXTENDING TO 3S29W INTO NE BRAZIL NEAR 2S45W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS FROM 1N-3N BETWEEN 3W-9W.
SCATTERED MODERATE CONVECTION IS S OF 4N BETWEEN 13W-21W.
SCATTERED MODERATE CONVECTION IS ALSO S OF 1N BETWEEN 37W-45W.

...DISCUSSION...

GULF OF MEXICO...
GENERALLY FAIR WEATHER IS PRESENT ACROSS MUCH OF THE GULF
REGION...WHERE NORTHWESTERLY FLOW ALOFT IS SUPPORTING
ATMOSPHERIC SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS. THE
SUBSIDENCE IS ALSO BEING SUPPORTED BY A SURFACE RIDGE OVER THE
GULF. ACROSS PORTIONS OF THE W GULF...SE TO S SURFACE WINDS OF
20 TO 25 KT ARE PRESENT AROUND THE SURFACE RIDGE. DEEP LAYER DRY
AIR IS ALSO PRESENT ACROSS MUCH OF THE GULF REGION. HOWEVER...
UPPER LEVEL MOISTURE IS STREAMING SOUTHEASTWARD ACROSS PORTIONS
OF THE N AND CENTRAL GULF. ACROSS THE CENTRAL AND SOUTHERN
PLAINS OF THE CONUS...A DEEP LAYER TROUGH IS PRESENT AND IS
ASSOCIATED WITH A SURFACE FRONT. THIS FRONT IS EXPECTED TO MOVE
SOUTHWARD INTO THE NW GULF SATURDAY MORNING AS A SURFACE COLD
FRONT...AND THEN EXTEND FROM NAPLES FLORIDA TO THE SOUTHERN BAY
OF CAMPECHE SUNDAY MORNING. IN THE WAKE OF THE COLD FRONT...
INCREASED NORTHERLY WINDS ARE FORECAST TO OCCUR OVER THE
GULF...WITH GALE CONDITIONS EXPECTED SATURDAY NIGHT INTO SUNDAY
OVER PORTIONS OF THE SW GULF. ALSO...RELATIVELY COOLER AND DRIER
CONDITIONS ARE PRESENT TO THE N OF THE FRONT.

CARIBBEAN SEA...
A DEEP LAYER TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A
SURFACE STATIONARY FRONT THAT EXTENDS FROM W OF HISPANIOLA NEAR
20N74W NORTHEASTWARD INTO THE W NORTH ATLC. LOW LEVEL
CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM EITHER
SIDE OF THIS FRONT. GENERALLY FAIR WEATHER CONDITIONS ARE
OCCURRING ACROSS MUCH OF THE CARIBBEAN REGION...WHERE CONFLUENCE
IN WESTERLY FLOW ALOFT IS PRESENT. 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
12N-14N BETWEEN 63W-71W. ALSO...INCREASED UPPER LEVEL MOISTURE
IS STREAMING NORTHEASTWARD ACROSS PORTIONS OF THE S AND E
CARIBBEAN.

ATLANTIC OCEAN...
THE DEEP LAYER TROUGH OVER THE CENTRAL ATLC IS ASSOCIATED WITH A
SURFACE STATIONARY FRONT THAT EXTENDS FROM W OF HISPANIOLA NEAR
20N74W TO 26N63W TO 32N50W TO NE OF THE DISCUSSION AREA. LOW
LEVEL CONVERGENCE IS SUPPORTING SCATTERED SHOWERS WITHIN 60 NM
EITHER SIDE OF THIS FRONT. TO THE W OF THIS FRONT...FAIR WEATHER
CONDITIONS ARE OCCURRING...WHERE SUBSIDENCE AND STABLE
ATMOSPHERIC CONDITIONS ARE PRESENT IN THE VICINITY OF A SURFACE
RIDGE. ALSO...ACROSS LOCATIONS IN THE CENTRAL AND E ATLC THAT
ARE SE OF THE STATIONARY FRONT...SUBSIDENCE ASSOCIATED WITH A
SURFACE RIDGE IS SUPPORTING FAIR WEATHER CONDITIONS. HOWEVER...A
DEEP LAYER TROUGH IS PRESENT OVER THE E ATLC N OF 23N E OF 24W
WITH AN ASSOCIATED UPPER LOW NEAR 33N16W. THE DEEP LAYER TROUGH
AND UPPER LOW ARE ASSOCIATED WITH A 1012 MB SURFACE LOW NEAR
26N19W AND A SURFACE TROUGH EXTENDING FROM 23N23W TO 23N20W TO
26N18W TO 27N19W TO 26N20W. THIS SURFACE LOW IS FORECAST TO HAVE
DISSIPATED BY 28/0000 UTC. THE DEEP LAYER TROUGH AND UPPER LOW
ARE ALSO ASSOCIATED WITH A SURFACE TROUGH EXTENDING FROM 26N15W
TO THE CANARY ISLANDS NEAR 29N15W TO 31N16W TO A 1012 MB SURFACE
LOW NEAR 31N18W TO 30N20W. THE 1012 MB SURFACE LOW NEAR 31N18W
IS FORECAST TO MOVE NORTHEASTWARD DURING THE NEXT DAY AND BE
LOCATED NEAR 35N10W AS A 1014 MB SURFACE LOW AT 28/0000 UTC. LOW
LEVEL CONVERGENCE AND ATMOSPHERIC INSTABILITY IN THE VICINITY OF
THE SURFACE LOWS AND SURFACE TROUGHS ARE SUPPORTING SCATTERED
SHOWERS N OF 25N E OF 21W. ACROSS THE TROPICAL ATLC...AN UPPER
LEVEL RIDGE IS S OF 8N E OF 54W. UPPER LEVEL DIVERGENCE
ASSOCIATED WITH THIS UPPER LEVEL RIDGE IS ENHANCING THE
CONVECTION ASSOCIATED WITH THE ITCZ. THIS UPPER LEVEL DIVERGENCE
IS ALSO SUPPORTING SCATTERED SHOWERS FROM 3N-6N BETWEEN 44W-51W
AND S OF 1N BETWEEN 45W-49W.

$$
COHEN


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