[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 282323
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 PM EDT SAT MAY 28 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.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE E ATLC ALONG 32W S OF 13N MOVING W AT AN
ESTIMATED SPEED OF 15-20 KT OR ABOUT 6-7 DEG/DAY.  THE WAVE
REMAINS POORLY DEFINED IN SATELLITE IMAGERY WITH NO SIGNIFICANT
CONVECTION.

TROPICAL WAVE APPROXIMATELY 200W NM E OF BARBADOS ALONG 56W S OF
19N MOVING W AT AN ESTIMATED SPEED OF 20-25 KT OR ABOUT 8-9
DEG/DAY. THE SATELLITE SIGNATURE IS MUCH IMPROVED FROM YESTERDAY
WITH SCATTERED MODERATE CONVECTION OBSERVED WITHIN THE ITCZ FROM
8N-11N.  MOST OF THE MOISTURE AND ASSOCIATED SHOWERS/TSTMS ARE
EXPECTED TO STAY PRIMARILY S OF 12N AFFECTING TRINIDAD/TOBAGO
TONIGHT AND SPREADING ACROSS VENEZUELA DURING THE NEXT 24 HOURS.

TROPICAL WAVE OVER THE CENTRAL CARIBBEAN ALONG 74W/75W S OF 18N
MOVING W AT AN ESTIMATED SPEED OF 15-20 KT OR ABOUT 7-8 DEG/DAY.
WHILE CONVECTION IS CURRENTLY MINIMAL...A 5-DAY SATELLITE LOOP
INDICATES THE WAVE IS REASONABLY LOCATED.

TROPICAL WAVE OVER CENTRAL AMERICA ALONG 86W S OF 16N MOVING W
AT AN ESTIMATED SPEED OF 10 KT OR ABOUT 4-5 DEG/DAY.  THE WAVE
IS FAIRLY WELL-DEFINED IN SATELLITE IMAGERY AND IS PRODUCING AN
AREA OF WIDELY SCATTERED TO LOCALLY SCATTERED MODERATE
CONVECTION MAINLY TO THE EAST OF AXIS OVER CENTRAL AMERICA FROM
E HONDURAS THROUGH W PANAMA.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 9N10W 6N50W 9N60W.  SCATTERED STRONG
CONVECTION OVER SW AFRICA FROM 7N-12N BETWEEN 7W-16W.  WIDELY
SCATTERED MODERATE CONVECTION FROM 4N-9N BETWEEN 21W-28W.
SCATTERED MODERATE CONVECTION FROM 8N-11N BETWEEN 50W-60W.

...DISCUSSION...

GULF OF MEXICO...
WEAK UPPER LEVEL RIDGING SPANS ACROSS THE GLFMEX ORIGINATING
FROM AN UPPER LEVEL HIGH CENTERED OVER CENTRAL AMERICA NEAR
GUATEMALA.  WATER VAPOR IMAGERY AND AREA UPPER LEVEL SOUNDINGS
INDICATE MIDDLE TO UPPER LEVEL MOISTURE HAS INCREASED A LITTLE
DURING THE LAST 24 HOURS BUT THE DEEP-LAYERED ATMOSPHERE STILL
REMAINS RELATIVELY DRY. AS A RESULT...ANOTHER DAY OF BELOW
NORMAL AFTERNOON SHOWERS/TSTMS OVER THE BULK OF FLORIDA.  THE
SLIGHT INCREASE IN MOISTURE MAY ALLOW A BIT MORE AFTERNOON
ACTIVITY ON SUNDAY ESPECIALLY OVER N FLORIDA AS A WEAK COLD
FRONT APPROACHES THE AREA.  LOOKING UPSTREAM...A MID/UPPER TROF
IS FORECAST TO MOVE ACROSS MEXICO SUNDAY AND BECOME ESTABLISHED
OVER THE FAR W GULF BY TUE.  MOST OF THE UPPER DYNAMICS ARE
EXPECTED TO BE N OF THE AREA SAVE RIGHT ALONG THE SE TEXAS
COAST. HOWEVER...DEEP-LAYERED SLY FLOW TO THE E OF THE TROUGH
SHOULD ALLOW MOISTURE TO RETURN IN EARNEST MON AND TUE PRODUCING
INCREASING THREAT FOR AFTERNOON SHOWERS/TSTMS OVER FLORIDA.

CARIBBEAN...
MIDDLE TO UPPER LEVEL RIDGING DOMINATES THE AREA WITH MEAN AXIS
EXTENDING FROM A ANTICYCLONE NEAR BELIZE ESE TO BEYOND 15N60W.
THE RIDGE IS PARTIALLY DISRUPTED BY A WEAK SHORTWAVE TROUGH
MOVING OVER CUBA.  AREA SOUNDINGS INDICATE THAT DEEP-LAYERED
MOISTURE REMAINS LARGELY IN PLACE PRODUCING ANOTHER DAY OF
ACTIVE CONVECTION OVER NEARLY ALL LAND MASSES. THE EXCEPTION
LIES OVER THE E CARIBBEAN WHERE AN AFRICAN DUST SURGE HAS
BROUGHT ABOUT SOME DRYING IN THE LOWER LEVELS AND A REDUCTION IN
CLOUDINESS AND SHOWERS.  THE LEADING EDGE OF THE DUST EXTENDS
FROM PUERTO RICO SW TO THE NE TIP OF COLOMBIA.  GUIDANCE
INDICATES LITTLE OVERALL CHANGE IN THE LARGE-SCALE PATTERN OVER
THE NEXT 2 DAYS AND AFTERNOON SHOWERS/TSTMS SHOULD CONTINUE FOR
AREAS W OF THE AFRICAN SURGE.

ATLANTIC...
ZONAL WLY FLOW PREVAILS IN THE UPPER LEVELS WITH AN E/W
ORIENTED MIDDLE TO UPPER LEVEL RIDGE EXTENDING ALONG 15N FROM
THE CARIBBEAN EWD TO 45W.  N OF THE RIDGE...TWO SHORTWAVE
TROUGHS EMBEDDED WITHIN THE WLY FLOW ARE MOVING ACROSS THE W
HALF OF THE AREA.  THE STRONGEST OF THESE DISTURBANCES EXTENDS
FROM 32N50W TO 22N60W AND IS GENERATING AN AREA OF CLOUDINESS
AND WIDELY SCATTERED TO LOCALLY SCATTERED SHOWERS/TSTMS TO ITS
EAST N OF 22N BETWEEN 35W-50W.  SECOND SHORTWAVE IS MOVING
ACROSS CUBA AND THE BAHAMAS BUT IS MOISTURE STARVED AND ONLY
ABLE TO PRODUCE SOME ISOLATED SHOWERS/TSTMS ALONG A REMNANT
FRONTAL TROUGH FROM 23N55W TO 25N73W.  THIS ACTIVITY IS EXPECTED
TO INCREASE DURING THE NEXT 24 HOURS AS UPPER DIFFLUENCE
INCREASES. OVER THE E ATLC...A PROGRESSIVE MID/UPPER LEVEL TROF
IS SWINGING EWD ACROSS THE CANARY ISLANDS TRAILING SWD ALONG
22N30W TO 6N44W. WATER VAPOR IMAGERY INDICATES THE TROUGH IS
FRAGMENTING WITH A CUT-OFF LOW FORMING NEAR 14N35W.  THE FORMING
UPPER LOW IS CAUSING INDUCED RIDGING TO THE EAST OVER THE CAPE
VERDE ISLANDS WITH RESULTING DIFFLUENT FLOW GENERATING ENHANCED
ITCZ E OF 25N.  CONFLUENCE ON THE BACK/WESTERN SIDE OF THE UPPER
LOW IS SUPPRESSING ITCZ CONVECTION BETWEEN 25W-50W.  THE UPPER
LOW IS EXPECTED TO REMAIN NEARLY STATIONARY THROUGH SUNDAY THEN
BEGIN TO LIFT NEWD AND WEAKEN.  AT THE SURFACE...THE SUBTROPICAL
RIDGE HAS BECOME MORE ESTABLISHED OVER THE ATLC WATERS WITH AXIS
EXTENDING FROM A 1026 MB HIGH LOCATED LOCATED OVER THE AZORES SW
THROUGH 30N50W TO CENTRAL FLORIDA.  THIS PATTERN HAS
STRENGTHENED THE ELY TRADES ACROSS THE AREA...ESPECIALLY THE
CARIBBEAN...ALLOWING A LARGE AREA OF AFRICAN DUST TO PUSH ACROSS
THE AREA S OF 22N TO THE ITCZ FROM AFRICA TO THE E CARIBBEAN.

$$
RHOME


WWWW
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