[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 230613
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0545 UTC

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 5N10W 3N15W 3N34W 1N45W. SCATTERED
MODERATE ISOLATED STRONG CONVECTION NOTED WITHIN 240 NM N OF THE
ITCZ AXIS BETWEEN 16W AND 25W. ISOLATED MODERATE OBSERVED S OF
5N BETWEEN 40W AND 50W.

...DISCUSSION...
GULF OF MEXICO...
AN UPPER TROUGH IS OVER THE WESTERN GULF ATTM ACCOMPANIED BY DRY
UPPER AIR GENERALLY W OF A LINE FROM 30N87W TO 20N97W. AN UPPER
ANTICYCLONE OVER THE N CENTRAL CARIBBEAN RIDGES NW OVER THE GULF
OF MEXICO ALONG POINTS 20N95W 27N88W 30N86W. 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 03 UTC A SURFACE COLD FRONT
EXTENDS FROM EXTREME W FLORIDA SW TO THE WESTERN BAY OF CAMPECHE
THEN TURNS NW BACKING UP AGAINST THE MEXICAN MOUNTAINS FROM
20N98W TO S TEXAS NEAR 26N98W THEN LOSES IDENTITY. UPPER
DIFFLUENCE E OF THE THE UPPER TROUGH IS STILL ENHANCING
CONVECTION AHEAD OF THE SURFACE FRONT ALONG LINE FROM 27N88W TO
BEYOND 30N85W WITH LIGHTNING DATA STILL REGISTERING HITS ALONG
THIS LINE. A 90 NM WIDE BAND OF OVERCAST LOW CLOUDS...AND
VISIBILITIES ESTIMATED IN THE 3-5 NM RANGE IN FOG...IS NOTED
FROM LOUISIANA TO THE SE TEXAS/NE OLD MEXICO BORDER. E OF THE
FRONT...THE ATLC SUBTROPICAL RIDGE EXTENDS W OVER THE AREA WITH
ITS AXIS ALONG 24N TO NEAR 90W.

CARIBBEAN...
AN UPPER ANTICYCLONE IS CENTERED NEAR 18N75W WITH ITS 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 WITHIN 90 NM EITHER SIDE OF LINE 12N61W 20N85W.

ATLANTIC...
AN UPPER ANTICYCLONE IS CENTERED OVER THE N CENTRAL CARIBBEAN
NEAR 18N75W WITH A RIDGE EXTENDING NE ALONG 27N70W TO JUST
BEYOND 34N60W. A MOISTURE PLUME IS NOTED ALONG THE RIDGE N OF
POINTS 23N80W 27N70W 25N55W. THE CENTRAL SUBTROPICAL ATLC IS
DOMINATED ALOFT BY AN UPPER TROUGH EXTENDING THROUGH CYCLONES
ALONG 35N14W 21N40W 15N55W. DRY UPPER AIR IS NOTED OVER THE SW
SEMICIRCLES OF EACH OF THESE CYCLONES. SHOWERS ARE ENHANCED NE
OF THE CYCLONE AT 21N40W. THE TROPICAL E ATLC IS DOMINATED ALOFT
BY AN ANTICYCLONE AT 6N18W WITH A RIDGE EXTENDING W TO NEAR
4N45W. UPPER DIFFLUENCE ALONG THIS RIDGE AXIS IS ENHANCING
CONVECTION NEAR 5N20W WITH THE DEBRIS MOISTURE SPREADING N TO
ALONG 21N BETWEEN 19W AND 34W. 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 15N35W 21N26W...THEN TURNS E ACROSS AFRICA ALONG
24N13W 30N8W. AT THE LOW LEVELS A HIGH PRES IS AT 34N36W 1030 MB
WITH A RIDGE SW THROUGH THE STRAITS OF FLORIDA. A SURFACE FRONT
HAS STALLED JUST OFFSHORE THE GEORGIA COAST WITH SHOWERS AND A
FEW TSTMS VERIFIED BY LIGHTNING DATA ALONG LINE 28N79W 33N75W.
LOCALLY BROKEN STRATOCUMULUS IS MOVING ANTICYCLONICALLY ACROSS
THE WATERS SE OF THE LOW LEVEL RIDGE.

$$
NELSON





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