[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 251117
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST WED FEB 25 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 6N9W 2N17W CROSSING THE EQUATOR
NEAR 21W EXTENDING TO 2S32W INTO NE BRAZIL NEAR 3S43W. SCATTERED
MODERATE/ISOLATED STRONG CONVECTION IS S OF 6N BETWEEN 6W-21W.
SCATTERED MODERATE CONVECTION IS S OF 1N BETWEEN 23W-29W.
SCATTERED MODERATE CONVECTION IS ALSO S OF 1N BETWEEN 36W-43W.

...DISCUSSION...

GULF OF MEXICO...
GENERALLY FAIR WEATHER IS PRESENT ACROSS MUCH OF THE GULF
REGION...WHERE CONFLUENCE IN WESTERLY FLOW ALOFT IS SUPPORTING
ATMOSPHERIC SUBSIDENCE AND STABLE ATMOSPHERIC CONDITIONS. THE
SUBSIDENCE IS ALSO BEING SUPPORTED BY A SURFACE RIDGE OVER THE
GULF...WITH A 1020 MB SURFACE HIGH OVER E MEXICO NEAR 23N90W.
ACROSS THE NW GULF...SE TO S SURFACE WINDS 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 GULF.

CARIBBEAN SEA...
A DEEP LAYER TROUGH OVER THE W ATLC IS ASSOCIATED WITH A SURFACE
COLD FRONT IN THE NW CARIBBEAN THAT EXTENDS FROM NE OF JAMAICA
NEAR 19N76W TO E OF CUBA NEAR 20N74W TO THE SW NORTH ATLC. LOW
LEVEL CONVERGENCE IS SUPPORTING ISOLATED SHOWERS WITHIN 60 NM
EITHER SIDE OF THIS FRONT. TRADE WINDS ARE FORECAST TO DIMINISH
OVER MUCH OF THE CARIBBEAN SEA THROUGH SUNDAY. GENERALLY FAIR
WEATHER CONDITIONS ARE OCCURRING ACROSS MUCH OF THE CARIBBEAN
REGION...WHERE A BROAD UPPER LEVEL RIDGE IS PRESENT. PATCHES OF
LOW LEVEL MOISTURE CONTINUE TO BE ADVECTED WESTWARD ACROSS THE
CARIBBEAN BY THE TRADE WINDS...WITH SCATTERED SHOWERS EMBEDDED
WITHIN THESE PATCHES OF LOW LEVEL MOISTURE. THE GREATEST
CONCENTRATION OF THESE SHOWERS IS FROM 13N-15N BETWEEN 62W-69W.

ATLANTIC OCEAN...
THE DEEP LAYER TROUGH OVER THE W ATLC IS ASSOCIATED WITH A
SURFACE COLD FRONT THAT EXTENDS FROM THE NW CARIBBEAN TO E OF
CUBA NEAR 20N74W TO 25N65W TO 32N53W 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. THIS SURFACE RIDGE EXTENDS SOUTHEASTWARD FROM A
1032 MB SURFACE HIGH OVER NE NORTH CAROLINA NEAR 37N76W.
ALSO...ACROSS LOCATIONS IN THE CENTRAL AND E ATLC THAT ARE SE OF
THE COLD 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 22N E OF 30W WITH AN
UPPER LOW NEAR 31N19W. THE DEEP LAYER TROUGH AND UPPER LOW ARE
ASSOCIATED WITH A DISSIPATING SURFACE COLD FRONT THAT EXTENDS
FROM 20N29W TO 22N21W TO 25N19W TO A 1010 MB SURFACE LOW W OF
THE CANARY ISLANDS NEAR 28N21W. THIS SURFACE LOW IS FORECAST TO
REMAIN NEARLY STATIONARY DURING THE NEXT DAY. ALSO...A 1009 MB
SURFACE LOW IS PRESENT NEAR 32N19W. THIS SURFACE LOW IS FORECAST
TO MOVE SOUTHWESTWARD DURING THE NEXT DAY AND MERGE WITH THE
AFOREMENTIONED 1010 MB SURFACE LOW W OF THE CANARY ISLANDS NEAR
28N21W...RESULTING IN A 1010 MB SURFACE LOW NEAR 28N21W AT
26/0600 UTC. LOW LEVEL CONVERGENCE AND ATMOSPHERIC INSTABILITY
IN THE VICINITY OF THE SURFACE LOWS AND DISSIPATING SURFACE COLD
FRONT ARE SUPPORTING SCATTERED SHOWERS N OF 24N BETWEEN 12W-23W.
ACROSS THE TROPICAL ATLC...AN UPPER RIDGE IS S OF 9N E OF 41W.
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 2N-5N
BETWEEN 40W-49W.

$$
COHEN




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