[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 231744
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
105 PM 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1730 UTC

...ITCZ...
ITCZ AXIS IS CENTERED ALONG 6N11W 1N22W 2N30W EQUATOR AT 43W
1S48W. SCATTERED MODERATE ISOLATED STRONG CONVECTION NOTED
WITHIN 240 NM S OF THE ITCZ AXIS BETWEEN 21W AND 33W. SCATTERED
MODERATE NOTED S OF 7N BETWEEN 46W AND 50W.

...DISCUSSION...
GULF OF MEXICO...
A SHEARING UPPER TROUGH IS SWEEPING EWD ACROSS THE SE CONUS AND
EXTENDS INTO THE NE GULF TO NEAR 26N89W. MODERATE MID TO UPPER
LEVEL DRY UPPER AIR WAS NOTED WITHIN THE TROUGH AXIS GENERALLY
WITHIN 120 NM EITHER SIDE OF LINE FROM 30N85W TO THE COAST OF
MEXICO NEAR 23N97W. WEAK SHORTWAVE RIDGE WITH AXIS ALONG 90W
WAS MOVING ACROSS THE WRN GULF STATES. THE PERIPHERY OF A LARGE
ANTICYCLONE OVER HISPANIOLA AND THE EXTREME SE BAHAMAS CONTINUES
TO EXERT AN INFLUENCE ON THE SE GULF OF MEXICO AND IS A MAJOR
FACTOR IN THE SHEARING OUT OF THE UPPER TROUGH MOVING ACROSS THE
SE. MOSTLY UPPER LEVEL MOISTURE...ORIGINATING FROM FORMER
CONVECTION OVER THE E PACIFIC AND CENTRAL AMERICA BETWEEN 85W
AND 95W...IS STREAMING NE ALONG THE PERIPHERY OF THE RIDGE. AT
15 UTC A SURFACE COLD FRONT EXTENDS FROM APALACHEE BAY FLORIDA
SW TO THE CENTRAL GULF NEAR 26N89W THEN BECOMES STATIONARY TO
THE MEXICAN COAST JUST E OF COATZACOALCOS. THE FRONT CONTINUED
AS A DISSIPATING STATIONARY FRONT BACKED UP AGAINST THE SIERRA
MADRE MOUNTAINS FROM THE CHIVELAS PASS NWD TO THE RIO GRANDE
RIVER. WEAKENING UPPER DIFFLUENCE E OF THE THE UPPER TROUGH
HAS ALLOWED CONVECTION AHEAD OF THE SURFACE FRONT TO WEAKEN
WITH SCATTERED SHOWERS AND THUNDERSTORMS NOTED FROM THE TAMPA
BAY CLEARWATER AREA OF FLORIDA TO 27N85W WITH LIGHTNING DATA
DECREASING MARKEDLY OVER THE PAST FEW HOURS. E OF THE
FRONT...THE ATLC SUBTROPICAL RIDGE EXTENDS W OVER THE AREA WITH
ITS AXIS ALONG 25N TO NEAR 85W/86W.

CARIBBEAN...
A LARGE PERSISTENT UPPER LEVEL ANTICYCLONE CENTERED NEAR
HISPANIOLA DOMINATED THE CARIBBEAN W OF 67W. THE WESTWARD
EXTENSION OF A CENTRAL ATLC UPPER TROUGH STILL EXTENDS INTO THE
FAR EASTERN CARIBBEAN BUT APPEARS TO BE FILLING WITH TIME. THIN
BROKEN CIRRIFORM CLOUDS ARE NOTED OVER THE FAR NW CARIBBEAN
ALONG THE PERIPHERY OF THE UPPER RIDGE/ANTICYCLONE. STRONG MID
TO UPPER LEVEL SUBSIDENCE IS NOTED IN ASSOCIATION WITH THE
ANTICYCLONE AND HAS SUPPRESSED ANY CONVECTIVE ACTIVITY. AT THE
LOW LEVELS THE ATLC SUBTROPICAL RIDGE EXTENDS W ACROSS THE NW
CARIBBEAN WITH ITS AXIS JUST N OF THE AREA ALONG 25N. LOCALLY
BROKEN LOW TRADE WIND CLOUDS WITH EMBEDDED SHOWERS ARE NOTED E
OF 70W WITH CLOUDINESS BECOMING BROKEN TO OVERCAST IN PATCHES
FROM JAMAICA TO W CUBA AND THE YUCATAN CHANNEL.

ATLANTIC...
AN UPPER ANTICYCLONE CENTERED OVER THE EXTREME SE BAHAMAS WITH A
RIDGE EXTENDING NE TO BEYOND 32N65W. A MOISTURE PLUME IS
SPILLING OVER THE RIDGE AXIS GENERALLY N OF POINTS 25N80W 25N70W
25N54W. THE CENTRAL SUB-TROPICAL ATLC IS DOMINATED BY A
POSITIVELY TILTED MID TO UPPER LEVEL TROUGH EXTENDING THROUGH
UPPER LEVEL CYCLONES ALONG 38N15W 24N33W AND 17N51W. DRY UPPER
AIR IS NOTED OVER THE SW SEMICIRCLES OF EACH OF THESE CYCLONES
WHILE MAINLY UPPER LEVEL CLOUDS AND SHOWERS ARE ENHANCED OVER
THE NE SEMICIRCLE. THE TROPICAL E ATLC IS DOMINATED BY AN UPPER
LEVEL ANTICYCLONE NEAR 5N23W WITH A RIDGE EXTENDING WWD ALONG 5N
TO 40W. UPPER DIFFLUENCE S OF THE RIDGE AXIS IS ENHANCING
CONVECTION WITHIN 240 NM N OF THE ITCZ BETWEEN 20W AND 33W
WITH THE DEBRIS MOISTURE SPREADING N TO ALONG 15N BETWEEN 15W
AND 35W. AT THE SURFACE SPRAWLING 1031 MB HIGH PRES CENTERED
NEAR 33N35W WITH A RIDGE EXTENDING SWWD THROUGH THE STRAITS OF
FLORIDA. THE SURFACE FRONT STALLED JUST OFFSHORE THE NE FLORIDA
COAST EARLIER HAS DISSIPATED AS OF 15 UTC. LOCALLY BROKEN
PATCHES OF STRATOCUMULUS ARE MOVING WWD ACROSS THE WATERS S OF
THE SURFACE RIDGE.

$$
COBB





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