[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 111053
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT MON AUG 11 2008

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS
OF SOUTH AMERICA...AND 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
1015 UTC.

...SPECIAL FEATURES...
A TROPICAL WAVE LOCATED OVER THE CENTRAL ATLANTIC ALONG 47W OR
ABOUT 780 NM EAST OF THE WINDWARD ISLANDS IS SUPPORTING AN AREA
OF DISORGANIZED SCATTERED SHOWERS AND THUNDERSTORMS FROM 12N-16N
BETWEEN 42W-50W. SATELLITE IMAGERY SHOWS SCATTERED MODERATE TO
ISOLATED STRONG CONVECTION NORTH OF A 1009 MB LOW EMBEDDED ON
THE WAVE AXIS NEAR 11N. THIS SYSTEM HAS THE POTENTIAL TO BECOME
A TROPICAL DEPRESSION DURING THE NEXT COUPLE OF DAYS AS IT MOVES
WESTWARD AT ABOUT 10 TO 15 KT.

...TROPICAL WAVES...
A TROPICAL WAVE IS ALONG 21W/22W S OF 17N MOVING W AT 10-15 KT.
SOME CYCLONIC TURNING IS SEEN ALONG THE WAVE AXIS NEAR 12N WITH
ISOLATED MODERATE SHOWERS FROM 7N-15N BETWEEN 18W-23W. THE WAVE
REMAINS MOSTLY EMBEDDED WITHIN THE ITCZ.

A TROPICAL WAVE IS ALONG 68W S OF 20N MOVING W 15-20 KT. THE
WAVE CONTINUES TO SHOW A NARROW NORTH-SOUTH MOISTURE MAXIMUM ON
SATELLITE IMAGERY. NO DEEP CONVECTION IS OBSERVED WITH SCATTERED
SHOWERS WITHIN 90 NM ON EITHER SIDE OF THE WAVE AXIS...ACROSS
PUERTO RICO AND THE MONA PASSAGE ON THE NORTHERN END AND THE ABC
ISLANDS ON THE SOUTHERN END. A SURGE OF AFRICAN DUST FOLLOWS
THIS WAVE.

A TROPICAL WAVE IS OVER THE CENTRAL CARIBBEAN ALONG 77W/78W S OF
21N MOVING W NEAR 15 KT. THE WAVE SHOWS AN INVERTED-V CLOUD
SIGNATURE ON SATELLITE IMAGERY ACROSS THE CARIBBEAN SEA WATERS.
THIS WAVE IS MOVING BENEATH A MIDDLE TO UPPER LEVEL LOW N OF 15N
LOCATED OVER CENTRAL CUBA WHICH EXTENDS TROUGHING S-SW TO THE
NICARAGUA AND HONDURAS BORDER. SCATTERED SHOWERS WITH EMBEDDED
TSTMS ARE ACROSS THE WINDWARD PASSAGE AND ERN CUBA AND MAY BE
MORE RELATED TO THE UPPER TROUGHING THAN TO THE TROPICAL WAVE.

...THE ITCZ...
THE ITCZ IS CENTERED ALONG 12N16W 11N20W 12N23W 11N34W 13N40W
12N45W 10N49W 7N58W. OUTSIDE OF THE CONVECTION ASSOCIATED WITH
THE TWO TROPICAL WAVES...SCATTERED MODERATE CONVECTION IS FROM
8N-12N BETWEEN 22W-29W.

...DISCUSSION...

GULF OF MEXICO...
AN UPPER-LEVEL HIGH CENTERED OVER THE BIG BEND REGION OF TEXAS
EXTENDS RIDGING OVER THE GULF WATERS NORTH OF 20N. AN UPPER
LEVEL TROUGH LIES SOUTH OF THE RIDGE AND EXTENDS FROM THE W ATLC
THROUGH THE STRAITS OF FLORIDA AND YUCATAN CHANNEL ALONG 19N TO
THE MEXICO COASTLINE NEAR 19N96W. THIS TROUGH IS AIDING IN
GENERATING ISOLATED SHOWERS ACROSS THE SE GULF FROM 23N-27N E OF
88W TO THE FLORIDA PENINSULA. AT THE SURFACE...A RIDGE ANCHORED
ON A 1017 MB HIGH OVER WRN CUBA INFLUENCES THE REMAINDER OF THE
GULF. THE SURFACE CIRCULATION AROUND THIS HIGH IS PROVIDING THE
WRN AND CENTRAL GULF WITH LIGHT TO MODERATE SOUTHERLY RETURN
FLOW. THESE WINDS ARE EXPECTED TO GRADUALLY INCREASE THROUGH TUE
AS A LOW PRESSURE SYSTEM DEVELOPS OVER TEXAS AND NE MEXICO.

CARIBBEAN SEA...
AN UPPER-LEVEL LOW IS LOCATED BETWEEN JAMAICA AND CUBA AND THE
CYCLONIC FLOW COVERS THE YUCATAN PENINSULA AND NW CARIBBEAN
EXTENDING EASTWARD OVER HISPANIOLA. UPPER DIFFLUENCE BETWEEN
THIS LOW AND A RIDGE CENTERED NEAR 12N74W WHICH COVERS MUCH OF
THE SRN CARIBBEAN BASIN IS SUPPORTING SCATTERED/NUMEROUS MODERATE
TO STRONG CONVECTION OVER THE SW CARIBBEAN FROM 9N-15N BETWEEN
75W-84W. MODERATE TO STRONG SUBSIDENCE AND DRY AIR IS OVER THE
ERN AND CENTRAL CARIBBEAN SEA E OF 74W. MODERATE TO STRONG
EASTERLY TRADE WINDS ARE BLOWING ACROSS THE BASIN WITH THE
STRONGEST WINDS OFFSHORE OF THE NRN COLOMBIAN COAST. TWO
TROPICAL WAVES ARE MOVING WWD ACROSS THE BASIN...SEE TROPICAL
WAVE SECTION FOR MORE DETAILS.

ATLANTIC OCEAN...
AN UPPER LEVEL TROUGH IS LOCATED OVER THE ERN U.S. INTO THE FAR
W ATLC WITH THE ASSOCIATED STATIONARY FRONTAL BOUNDARY ENTERING
THE AREA NEAR 32N70W DISSIPATING TO NORTH OF GRAND BAHAMA
ISLAND. AN UPPER RIDGE IS TO THE SE CENTERED NEAR 27N67W. UPPER
DIFFLUENCE BETWEEN THIS HIGH THE UPPER-LEVEL LOW SPINNING OVER
ERN CUBA IS GENERATING SCATTERED SHOWERS AND TSTMS WITHIN 120 NM
EAST OF A LINE FROM THE ERN FLORIDA STRAITS NE OVER GRAND BAHAMA
ISLAND TO NEAR 32N68W. UPPER DIFFLUENCE ON THE NRN EDGE OF THE
UPPER RIDGE IS PRODUCING AND AREA OF SCATTERED SHOWERS AND TSTMS
FROM 26N-31N BETWEEN 55W-67W. ELSEWHERE AN UPPER LOW IS OVER THE
CENTRAL ATLC NEAR 28N51W WITH ANOTHER WEAK UPPER-LEVEL LOW OVER
THE ERN ATLC NEAR 25N35W. AN UPPER-LEVEL HIGH IS LOCATED NEAR
18N44W EXTENDING A RIDGE ACROSS THE DEEP TROPICS. THIS UPPER
SYSTEM IS ENHANCING CONVECTION ALONG THE ITCZ. OTHERWISE...THE
ATLANTIC FORECAST AREA IS DOMINATED BY A 1025 MB SURFACE HIGH
CENTERED NEAR 34N48W. THIS HIGH EXTENDS A RIDGE SW TO THE
BAHAMAS AND WILL REMAIN NEARLY STATIONARY DURING THE NEXT 24
HOURS OR SO.

$$
HUFFMAN


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