[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 251050
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT WED 25 MAY 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE FAR E ATLC OFF THE AFRICAN COAST ALONG
20W/21W S OF 17N MOVING W 10-15 KT. WIDESPREAD CLOUDINESS AND
AREAS OF DEEP CONVECTION S OF THE ITCZ ACCOMPANIES THE WAVE.
SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS WITHIN 100 NM
OF 6N BETWEEN 16W AND THE WAVE AXIS. UPPER LEVEL SW FLOW IS
ADVECTING HIGH LEVEL MOISTURE AND CLOUDINESS FROM THIS ACTIVITY
INTO W PORTIONS OF AFRICA.

CENTRAL ATLC TROPICAL WAVE EXTENDS FROM 13N52W INLAND OVER SOUTH
AMERICA BEYOND 5N55W MOVING W 10 KT. WEAK LOW LEVEL ROTATION IS
NOTED IN SATELLITE IMAGERY WITH SCATTERED MODERATE/ISOLATED
STRONG CONVECTION INLAND OVER SOUTH AMERICA.

CENTRAL CARIBBEAN TROPICAL WAVE IS LOCATED ALONG 72W S OF 14N
MOVING W 10 KT. THE WAVE DOES NOT EXHIBIT A GOOD SATELLITE
SIGNATURE AND THE PRESENT POSITION IS BASED UPON CONTINUITY. NO
ASSOCIATED DEEP CONVECTION.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 11N14W 12N21W 10N39W 9N48W 10N57W
9N62W. SCATTERED MODERATE/STRONG CONVECTION IS WITHIN 150 NM
ALONG THE COAST OF AFRICA FROM 5N-8N. CLUSTERS OF SCATTERED
MODERATE/ISOLATED STRONG CONVECTION ARE WITHIN 150 NM EITHER
SIDE OF AXIS FROM 18W-28W AND WITHIN 120 NM OF 4N FROM 24W-36W.

...DISCUSSION...

GULF OF MEXICO...
MID/UPPER TROUGH EXTENDS FROM NE FLORIDA SW TO THE MEXICAN COAST
NEAR TAMPICO AND CONTINUES TO BE THE MAIN PLAYER IN THE WEATHER
OF THE GULF AS IT PRODUCES CONFLUENT FLOW ALOFT AND STRONG
SUBSIDENCE ACROSS MOST OF THE AREA. RESULTING AIRMASS IS QUITE
DRY THROUGH ALL BUT THE LOWEST LEVELS. THIS PATTERN IS PRODUCING
CLEAR SKIES AND TRANQUIL WEATHER OVER THE AREA EXCEPT IN THE
IMMEDIATE VICINITY OF THE COLD FRONT EXTENDING ACROSS FLORIDA
JUST S OF JACKSONVILLE TO INLAND OVER LOUISIANA NEAR NEW
ORLEANS. NUMERICAL GUIDANCE INDICATES THAT THIS UPPER LEVEL
TROUGH WILL CONTINUE TO SLIDE SLOWLY E KEEPING THE GULF AND
FLORIDA ON THE CONFLUENT/DRY SIDE. AT THE SAME TIME...THE WEAK
COLD FRONT WILL MOVE S INTO CENTRAL FLORIDA THIS AFTERNOON THEN
BECOME INCREASINGLY DIFFUSE AS IT PUSHES THROUGH CENTRAL FLORIDA
EXTENDING FROM THE W ATLC TO JUST S OF LAKE OKEECHOBEE BY
TONIGHT. DEEP-LAYERED MOISTURE WILL BE ABSENT COURTESY OF THE
UPPER TROUGH BUT LOW LEVEL MOISTURE POOLING ALONG THE BOUNDARY
MAY BE SUFFICIENT TO ALLOW A FEW ISOLATED SHOWERS/THUNDERSTORMS
TO GENERATE. EXPECT WHAT LITTLE ACTIVITY TO BE PRIMARILY FOCUSED
ALONG THE FRONTAL BOUNDARY.

CARIBBEAN...
BROAD AREA OF LOW PRESSURE REMAINS LOCATED OVER THE N CENTRAL
CARIBBEAN WITH 1009 MB LOW ANALYZED IN THE VICINITY OF JAMAICA
DRIFTING NE. THE LOW IS LOCATED ALONG THE TAIL END OF A
PERSISTENT SURFACE TROUGH EXTENDING FROM THE CENTRAL ATLC
ACROSS THE N LEEWARD ISLANDS...PUERTO RICO AND HISPANIOLA.
STRONG LOW LEVEL CONVERGENCE ALONG THIS BOUNDARY CONTINUES TO
PRODUCE SCATTERED STRONG THUNDERSTORMS OVER HISPANIOLA WITH MORE
ISOLATED ACTIVITY FROM PUERTO RICO TO OVER THE N LEEWARD AND
VIRGIN ISLANDS. THIS LOW AND TROUGH COULD CONTINUE TO GENERATE
SHOWERS/THUNDERSTORMS ACROSS THIS AREA THROUGH TODAY.
THEREFORE...THE POTENTIAL EXIST FOR LOCALIZED HEAVY RAINFALL AND
FLOODING ESPECIALLY IN MOUNTAINOUS AREAS THROUGH TODAY UNTIL THE
TROUGH AND ASSOCIATED AXIS OF SHOWERS/THUNDERSTORMS LIFTS SLOWLY
N INTO THE ATLC. DIURNAL CONVECTION OVER INTERIOR SECTIONS OF
CENTRAL AMERICA ARE DISSIPATING AND WILL CONTINUE TO DIE OUT
THROUGH THE MORNING. LOW LEVEL MOISTURE COULD ALSO BE ON THE
INCREASE AS A WEAK TROPICAL WAVE...CURRENTLY ALONG 72W...GETS
PULLED N AROUND THE W PERIPHERY OF THE SUBTROPICAL RIDGE.

ATLANTIC...
LARGE MID/UPPER LEVEL CLOSED LOW ALONG THE NE UNITED STATES
COAST CONTINUES TO AMPLIFY S PUSHING A WEAK COLD FRONT OFF THE
SE UNITED STATES COAST AND INTO THE N GULF. THIS BOUNDARY NOW
EXTENDS THROUGH 32N74W TO JUST S OF JACKSONVILLE FLORIDA AND
WILL EXTEND FROM ROUGHLY 32N70W TO CENTRAL FLORIDA JUST S OF
LAKE OKEECHOBEE BY THIS EVENING. UPPER DYNAMICS IMPROVEMENT HAS
REACHED ITS PEAK AS THE SHORTWAVE TROUGH HAS REACHED THE BASE OF
THE LARGE SCALE TROUGH AND WILL NOW BECOME LESS LIKELY TO
SUPPORT FURTHER DEVELOPMENT OF SHOWERS/THUNDERSTORMS IN THE W
ATLC. OVER THE CENTRAL ATLC...ZONAL FLOW ALOFT PREVAILS N OF 20N
WITH A RATHER WEAK RIDGING ALONG 54W N OF 26N. AREA OF
SUBSIDENCE AND DRY AIR ARE OVER THE CENTRAL ATLC FROM 23N-32N
BETWEEN 36W-50W. FURTHER E...A SHARP SHORTWAVE TROUGH EXTENDS
THROUGH 32N34W 25N41W WITH ATTENDANT 1003 MB SURFACE LOW N OF
THE REGION WITH A SURFACE TROUGH ENTERING THE CENTRAL ATLC NEAR
32N33W S ALONG 26N37W THEN SW ALONG 22N50W TO THE N LEEWARD
ISLANDS. WIDESPREAD CLOUDINESS AND SCATTERED SHOWERS/ISOLATED
THUNDERSTORMS ARE WITHIN 500 NM E OF THE LOW/TROUGH N OF 20N E
OF 40W AND WITHIN 250 NM S OF THE TROUGH BETWEEN 40W-60W.
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS WILL LINGER ALONG THE
TROUGH E OF 50W. OVER THE E ATLC...A SECOND EVEN SHARPER UPPER
TROUGH EXTENDS FROM THE CANARY ISLANDS INTO THE DEEP TROPICAL
ATLC NEAR 10N36W. UPPER DIFFLUENCE TO THE E IS SUPPORTING
ENHANCED ITCZ ACTIVITY E OF 40W. AFRICAN DUST REMAINS OVER THE
AREA FROM 10N-20N BETWEEN 30W-55W AS WELL AS BEING DRAWN NE TO
OVER THE CANARY AND MADEIRA ISLANDS.

$$
WALLACE



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