[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231413
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 AM EST SAT FEB 23 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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
1115 UTC

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 1N21W 4N30W 4N40W 1N48W.
SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 330
NM N AND WITHIN 240 NM S OF THE ITCZ AXIS BETWEEN 28W AND 30W.
ISOLATED MODERATE OBSERVED S OF 8N BETWEEN 39W AND 51W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER TROUGH IS SWINGING E ACROSS THE N CENTRAL GULF ATTM
ACCOMPANIED BY DRY UPPER AIR GENERALLY W OF A LINE FROM 30N870W
TO 20N97W. AN UPPER ANTICYCLONE OVER THE SE BAHAMAS RIDGES W
OVER THE GULF OF MEXICO TO A CREST ALONG POINTS 20N95W 28N81W.
UPPER LEVEL MOISTURE...ORIGINATING FROM FORMER CONVECTION OVER
THE E PACIFIC NEAR 15N95W AND OVER CENTRAL AMERICA BETWEEN 85W
AND 95W...IS STREAMING NE UNDER THIS RIDGE. AT 09 UTC A SURFACE
COLD FRONT EXTENDS FROM 30N89W SW TO THE CENTRAL GULF NEAR
26N90W THEN BECOMES STATIONARY THROUGH A WEAK LOW PRES IN THE
BAY OF CAMPECHE NEAR 20N94W THEN TURNS W AND NW BACKING UP
AGAINST THE MEXICAN MOUNTAINS FROM 20N98W TO S TEXAS NEAR
28N100W. UPPER DIFFLUENCE E OF THE THE UPPER TROUGH IS STILL
ENHANCING CONVECTION AHEAD OF THE SURFACE FRONT ALONG LINE FROM
27N88W TO BEYOND 30N81W WITH LIGHTNING DATA STILL REGISTERING
HITS OVER THE GULF ALONG THIS LINE. A 75 NM WIDE BAND OF
OVERCAST LOW CLOUDS...AND VISIBILITIES ESTIMATED IN THE 3-5 NM
RANGE IN FOG...IS NOTED FROM 29N90W TO 24N97W. E OF THE
FRONT...THE ATLC SUBTROPICAL RIDGE EXTENDS W OVER THE AREA WITH
ITS AXIS ALONG 24N TO NEAR 88W.

CARIBBEAN...
AN UPPER ANTICYCLONE IS CENTERED NEAR 21N73W WITH ITS
ANTICYCLONIC ENVELOPE DOMINATING THE CARIBBEAN W OF 67W. THE
WESTERN PORTION OF A CENTRAL ATLC UPPER TROUGH STILL EXTENDS
INTO THE EASTERN CARIBBEAN BUT APPEARS TO BE FILLING WITH TIME.
THIN BROKEN CIRRIFORM CLOUDS ARE NOTED OVER THE NW CARIBBEAN
ALONG THE UPPER RIDGE. DRY UPPER AIR IS INDICATED ELSEWHERE
ALOFT. AT THE LOW LEVELS THE ATLC SUBTROPICAL RIDGE EXTENDS W
ACROSS THE NW CARIBBEAN WITH ITS AXIS ROUGHLY JUST N OF THE AREA
ALONG 24N. LOCALLY BROKEN LOW TRADE WINDS CLOUDS WITH EMBEDDED
SHOWERS ARE NOTED E OF 70W WITH CLOUDINESS BECOMING BROKEN TO
OVERCAST ROM JAMAICA TO W CUBA.

ATLANTIC...
AN UPPER ANTICYCLONE IS CENTERED OVER THE SE BAHAMAS WITH A
RIDGE EXTENDING NE TO BEYOND 32N68W. A MOISTURE PLUME IS NOTED
ALONG THE RIDGE N OF POINTS 25N80W 25N54W. THE CENTRAL
SUB-TROPICAL ATLC IS DOMINATED ALOFT BY AN UPPER TROUGH
EXTENDING THROUGH CYCLONES ALONG 36N14W 22N40W 15N55W. DRY UPPER
AIR IS NOTED OVER THE SW SEMICIRCLES OF EACH OF THESE CYCLONES
WHILE SHOWERS ARE ENHANCED OVER THE NE SEMICIRCLE. THE TROPICAL
E ATLC IS DOMINATED ALOFT BY AN ANTICYCLONE AT 5N14W WITH A
RIDGE EXTENDING W TO NEAR 1N40W. UPPER DIFFLUENCE ALONG THIS
RIDGE AXIS IS ENHANCING CONVECTION NEAR 2N23W WITH THE DEBRIS
MOISTURE SPREADING N TO ALONG 18N BETWEEN 15W AND 28W. A WELL
DEFINED 300 NM WIDE MOISTURE PLUME...ORIGINATING FROM CONVECTION
OVER S AMERICA NEAR 2S50W...STREAMS NE ALONG THE TROPICAL UPPER
RIDGE...ROUGHLY ALONG 3N48W 20N25W THEN TURNS E ACROSS AFRICA
ALONG 29N9W 27N1W. AT THE LOW LEVELS A HIGH PRES IS AT 39N33W
1030 MB WITH A RIDGE SW THROUGH THE STRAITS OF FLORIDA. A
SURFACE FRONT HAS STALLED JUST OFFSHORE THE NE FLORIDA COAST
WITH SHOWERS AND A FEW TSTMS VERIFIED BY LIGHTNING DATA NEAR
29N80W. LOCALLY BROKEN STRATOCUMULUS IS MOVING ANTICYCLONICALLY
ACROSS THE WATERS SE OF THE LOW LEVEL RIDGE.

$$
NELSON






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