[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 281044
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1045 UTC.

...TROPICAL WAVES...

TROPICAL WAVE OVER THE FAR E ATLANTIC IS ALONG 29W S OF 15N
MOVING W AT 15 KT.  SOME CYCLONIC ROTATION IS NOTED WITHIN THE
LOW CLOUD FIELD W OF THE CAPE VERDE ISLANDS.  CONVECTION IS
CONFINED TO THE ITCZ.

TROPICAL WAVE OVER THE CENTRAL ATLC IS ALONG 48W/49W SOUTH OF
13N MOVING W AT 15 KT. THIS WAVE IS POORLY DEFINED IN SATELLITE
IMAGERY WITH CURRENT POSITION BASED MAINLY UPON EXTRAPOLATION
AND PAST WAVE PROPAGATION SPEED.  LARGE AFRICAN DUST SURGE IS
SUPPRESSING CONVECTION.  CONVECTION IS CONFINED TO THE ITCZ.

TROPICAL WAVE OVER THE E CARIBBEAN IS ALONG 70W S OF 18N MOVING
WEST AT 15 KT. SOME CYCLONIC ROTATION IS NOTED WITHIN THE LOW
CLOUD FIELD.  SCATTERED MODERATE TO STRONG CONVECTION IS NOTED
INLAND OVER VENEZUELA FROM 6N-10N BETWEEN 66W-69W.

TROPICAL WAVE OVER CENTRAL AMERICA IS ALONG 85W S OF 16N MOVING
W AT 15 KT.  SATELLITE IMAGERY SHOWS SOME CURVATURE OVER THE SW
CARIBBEAN AND CENTRAL AMERICA.  SCATTERED MODERATE TO STRONG
CONVECTION IS ALONG THE COASTS OF COSTA RICA AND NICARAGUA FROM
9N-12N BETWEEN 81W-84W.

...ITCZ...

ITCZ AXIS IS CENTERED ALONG 10N10W 9N20W 8N25W 9N29W 7N40W 9N49W
8N60W.  CLUSTERS OF SCATTERED MODERATE TO ISOLATED STRONG
CONVECTION ARE FROM 5N-10N BETWEEN 17W-24W.  SCATTERED MODERATE
CONVECTION IS FROM 6N-9N BETWEEN 28W-31W...AND FROM 6N-8N
BETWEEN 52W-57W.

...DISCUSSION...

GULF OF MEXICO...
SURFACE RIDGING DOMINATES THE GULF OF MEXICO DUE TO A 1021 MB
HIGH OVER THE W ATLANTIC NEAR 30N65W.  WINDS ARE LIGHT FROM THE
E AND SE.  SCATTERED MODERATE TO CONVECTION IS MOSTLY INLAND
OVER S MEXICO FROM 16N-19N BETWEEN 92W-94W.  WIDELY SCATTERED
MODERATE CONVECTION IS ALSO INLAND ALONG THE FOOTHILLS OF THE
SIERRA MADRE ORIENTAL MOUNTAINS FROM 22N-24N BETWEEN 97W-99W.
IN THE UPPER LEVELS...A RIDGE EXTENDS FROM THE YUCATAN PENINSULA
TO LOUISIANA WITH AXIS ALONG 92W.  MOISTURE AND HIGH CLOUDS ARE
W OF THE RIDGE AXIS BETWEEN 92W-102W.  SUBSIDENCE COVERS THE
REMAINDER OF THE GULF OF MEXICO.  EXPECT A WEAK COLD FRONT
CURRENTLY OVER THE SE UNITED STATES TO MOVE INTO N FLORIDA SAT
AFTERNOON.  THE FRONT IS PRESENTLY MOISTURE STARVED BUT MAY
PRODUCE WIDELY SCATTERED SHOWERS/ THUNDERSTORMS ACROSS N FLORIDA
IN THE AFTERNOON.  THE REMAINDER OF THE GULF WILL HAVE LIGHT SE
AND S SURFACE FLOW.

CARIBBEAN SEA...
THE TWO TROPICAL WAVES ARE THE MAIN SURFACE FEATURE IN THE
CARIBBEAN.  SEE ABOVE.  AN AFRICAN DUST SURGE IS OVER THE E
CARIBBEAN BEHIND THE WAVE ALONG 70W MOVING WEST 15 KT.  THIS
AIRMASS WILL CONTINUE TO SPREAD WESTWARD ACROSS THE AREA WITH
DUST...LOW LEVEL DRYING...AND A DECREASED CHANCE OF AFTERNOON
SHOWERS/TSTMS IN ITS WAKE.  IN THE UPPER LEVELS... A RIDGE
PREVAILS OVER THE WESTERN CARIBBEAN W OF 80W WITH AXIS FROM
COSTA RICA TO THE YUCATAN PENINSULA.  UPPER LEVEL MOISTURE IS
NOTED OVER CENTRAL AMERICA.  THE BASE OF A TROUGH IS OVER THE
NORTHERN CARIBBEAN N OF 18N BETWEEN 60W-80W.  UPPER LEVEL
MOISTURE IS ALSO NOTED OVER THIS AREA TO INCLUDE JAMAICA...
HISPANIOLA...AND PUERTO RICO.  EXPECT THE TROPICAL WAVES TO
CONTINUE MOVING W IN THE NEXT 24 HOURS.

ATLANTIC OCEAN...
A 1021 MB HIGH IS OVER THE W ATLANTIC NEAR 30N65W.  A FRONTAL
TROUGH IS FURTHER E ALONG 32N56W 27N60W 23N64W.  BROKEN LOW
CLOUDS ARE WITHIN 120 NM OF THE TROUGH.  AN AREA OF SCATTERED
MODERATE CONVECTION IS E OF THE TROUGH FROM 23N-28N BETWEEN
50W-55W.  A LARGE 1028 MB HIGH NEAR 36N33W DOMINATES THE E
ATLANTIC N OF 18N AND E OF 50W.  ELSEWHERE... SATELLITE IMAGERY
SHOWS AN EXTENSIVE AREA OF AFRICA DUST COVERING THE ENTIRE AREA
S OF 23N TO THE ITCZ E OF THE LESSER ANTILLES.  IN THE UPPER
LEVELS... A TROUGH-RIDGE-TROUGH PATTERN PREVAILS. A BROAD/FLAT
TROUGH IS OVER THE W ATLANTIC W OF 60W...A RIDGE IS OVER THE
CENTRAL ATLANTIC FROM THE LESSER ANTILLES TO BEYOND 32N43W...AND
A TROUGH IS OVER THE E ATLANTIC FROM THE AZORES TO 13N40W.
EXPECT THE W EXTENT OF THE FRONTAL TROUGH TO LIFT SLOWLY NWD AS
A SHORTWAVE TROUGH IN THE UPPER LEVELS MOVES ACROSS E CUBA AND
THE BAHAMAS TOMORROW.  THIS SHOULD PRODUCE INCREASING
SHOWERS/TSTMS NE OF THE BAHAMAS SAT.

$$
FORMOSA



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