[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 222338
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
705 PM EST TUE 22 FEB 2005

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHEASTERN SECTIONS
OF SOUTH AMERICA...AND ATLANTIC OCEAN TO THE AFRICAN COAST FROM
THE EQUATOR TO 32N. THE FOLLOWING INFORMATION IS BASED ON
SATELLITE IMAGERY...WEATHER OBSERVATIONS...RADAR...AND
METEOROLOGICAL ANALYSIS.

BASED ON 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
2245 UTC.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 7N0 3N20W 4N35W 1N55W. ISOLATED
MODERATE CONVECTION EXTENDING FROM COASTAL SECTIONS OF THE IVORY
COAST NW TO LIBERIA/SIERRA LEONE. WIDELY SCATTERED MODERATE
WITHIN 75 NM OF THE AXIS BETWEEN 10W-20W. ISOLATED MODERATE
ELSEWHERE S OF THE ITCZ BETWEEN 12W-20W. WIDELY SCATTERED
MODERATE 150 NM S OF THE AXIS BETWEEN 38W-53W.

...DISCUSSION...

GULF OF MEXICO...
A LARGE REX BLOCK OFF THE CALIFORNIA COAST IS KEEPING THE
DOWNSTREAM PATTERN OVER THE GULF OF MEXICO RATHER STAGNANT
WITH BROAD SW/W FLOW STREAMING FROM MEXICO TO THE W ATLC WATERS.
A DISCONTINUOUS SUBTROPICAL JET IS EMBEDDED IN THE FLOW WITH A
80-90 KT JET CORE RUNNING ACROSS SE TX TO THE FL PANHANDLE...AND
A LARGE PLUME OF TROPICAL MOISTURE SPREADING FROM W TO E OVER
THE GULF WATERS. A SFC RIDGE IS ORIENTED ACROSS THE AREA FROM S
FL TO SE TX AND IS PRODUCING RELATIVELY FAIR WEATHER OVER THE
AREA...BUT WEAK LOW-LEVEL CONVERGENCE WITHIN THE RIDGE IS
SUPPORTING AN AREA OF WIDELY SCATTERED SHOWERS/TSTMS OVER THE NE
GULF FROM 25N-29N BETWEEN 84W-89W. A QUASI-STATIONARY FRONT
DRAPED ACROSS THE SE U.S. WILL SLOWLY DROP S OVER THE NEXT 24-48
HRS AND WAVES OF SHOWERS/TSTMS WILL DEVELOP OVER THE N GULF
WATERS BEGINNING ON WED. OTHER AREAS OF SHOWERS/TSTMS WILL
CONTINUE TO DEVELOP ALONG THE FRONT THRU THE REST OF THE
WEEK/WEEKEND AS A SERIES OF FRONTAL LOWS DEVELOPS AND TRACKS
NEWD ACROSS FL...POSSIBLY BRINGING SOME MUCH NEEDED RAIN TO THE
PENINSULA.

CARIBBEAN...
THE EASTERLY TRADES HAVE RELAXED A BIT NOW THAT HIGH PRES OVER
THE ATLC HAS WEAKENED YET THE WEATHER PATTERN HAS NOT REALLY
CHANGED. BANDS OF SHOWERS CONTINUE TO MOVE TO THE W...WITH THE
MOST NOTABLE AREA LOCATED OVER THE E CARIBBEAN WATERS FROM
12N-16N BETWEEN 63W-73W. OTHER SHOWERS ARE LOCATED OFF THE SE
COAST OF JAMAICA AND MOVING INLAND OVER COSTA RICA AND NICARAGUA
BUT OVERALL DRY AIR IN THE MID/UPPER LEVELS IS INHIBITING DEEP
CONVECTION. IN FACT...AN UPPER TROF EXTENDING FROM THE CAYMAN
ISLANDS SWD PAST COSTA RICA IS PRODUCING STRONG SUBSIDENCE OVER
THE W CARIBBEAN WHICH IS THEN BEING ADVECTED EWD ACROSS THE REST
OF THE AREA IN BROAD SW/W FLOW. THE E CARIBBEAN SHOWERS WILL
CONTINUE MOVING W ACROSS THE AREA OVER THE NEXT 2-3 DAYS WITH A
SECOND WAVE OF SHOWERS POSSIBLY CROSSING THE LESSER ANTILLES
THU/FRI.

ATLANTIC...
ZONAL UPPER LEVEL WESTERLY FLOW EXTENDS ACROSS THE W ATLC WATERS
AND IS UNDERLAIN BY A RIDGE OF SFC HIGH PRES WHICH EXTENDS FROM
S FL EWD TO A 1023 MB HIGH NEAR 26N70W TO A SECOND 1023 MB HIGH
NEAR 28N58W THEN NE BEYOND 32N50W. A SHORTWAVE TROF OFF THE
COAST OF NOVA SCOTIA IS DROPPING A COLD FRONT SWD TO 32N BUT THE
SFC RIDGE IS KEEPING THIS FEATURE OUT OF THE AREA FOR NOW.
FARTHER E...A BROAD UPPER LEVEL TROF IS LOCATED ALONG 30W AND N
OF 23N WITH A SFC TROF EXTENDING ALONG 32N26W 28N26W 20N33W. AN
AREA OF DIFFLUENCE AHEAD OF THE MID/UPPER TROF IS PRODUCING
SCATTERED MODERATE CONVECTION N OF 24N BETWEEN 21W-26W...AND
THIS AREA WILL CONTINUE PROPAGATING TO THE E APPROACHING THE
WESTERNMOST CANARY ISLANDS BY WED MORNING. FARTHER S...ZONAL
FLOW EXTENDS ACROSS THE ENTIRE TROPICAL ATLC WITH A 110-120 KT
UPPER LEVEL JET RUNNING ALONG 20N/21N JUST N OF THE CAPE VERDE
ISLANDS. THIS NON-DIFFLUENT PATTERN IS PROVIDING LITTLE SUPPORT
FOR ITCZ CONVECTION...WHICH IS FOCUSED CLOSE TO THE AXIS AND
SPORADIC AT BEST.

$$
BERG


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