[Tropical] Tropical Weather Discussion

[EMWIN Server]

AXNT20 KNHC 221038
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
805 AM EDT SUN JUL 22 2007

TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL
AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHERN
SECTIONS OF SOUTH AMERICA...AND THE 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.

...TROPICAL WAVES...
TROPICAL WAVE IS OVER THE CAPE VERDE ISLANDS ALONG 24W S OF 18N
MOVING W 10-15 KT. THE WAVE IS FAIRLY WELL ORGANIZED WITH
CYCLONIC TURNING COVERING A BROAD AREA. A SFC LOW MAY BE ADDED
ALONG THE WAVE AXIS ON THE 12Z SFC MAP. CONVECTION IS CONFINED
TO THE ITCZ FROM 10N-12N BETWEEN 19W-25W.

TROPICAL WAVE IS APPROACHING THE LESSER ANTILLES ALONG 60W/61W S
OF 20N MOVING W NEAR 15 KT. BROAD LOW LEVEL INVERTED-V SIGNATURE
IS NOTED ON SATELLITE IMAGERY. CONVECTION HAS SLIGHTLY INCREASE
ON EITHER SIDE OF THE AXIS EARLY THIS MORNING. SCATTERED SHOWERS
AND TSTMS ARE FROM 15N-19N BETWEEN 58W-65W. ANTIGUA AND
GUADELOUPE ARE REPORTING MAINLY LIGHT SHOWERS AND TSTMS WITH THE
PASSAGE OF THE WAVE. THIS FEATURE IS FORECAST TO ENTER THE
CARIBBEAN SEA THIS MORNING. MOISTURE FROM THIS WAVE SHOULD
AFFECT THE UK/US VIRGIN ISLANDS AND PUERTO RICO LATE TODAY
THROUGH MONDAY.

TROPICAL WAVE IS IN THE CARIBBEAN ALONG 80W S OF 21N MOVING W
NEAR 15 KT. A BROAD LOW LEVEL INVERTED-V SIGNATURE IS NOTED.
CONVECTION HAS ALSO INCREASE OVER THE SW CARIBBEAN WITH CLUSTERS
OF SCATTERED MODERATE CONVECTION FROM 12N-15N BETWEEN 78W-81W.
THIS FEATURE WILL MOVE ACROSS CENTRAL AMERICA AND THE NW
CARIBBEAN TODAY...REACHING THE YUCATAN PENINSULA AND BELIZE
MONDAY MORNING.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 16N20W 9N30W 10N46W 11N58W. CLUSTERS
OF SCATTERED MODERATE CONVECTION ARE FROM 10N-12N BETWEEN
19W-25W...AND FROM 5N-10N BETWEEN 27W-41W.

...DISCUSSION...
GULF OF MEXICO...
WEAK PRESSURE PATTERN CHARACTERIZED BY WEAK RIDGING AND A WEAK
SFC TROUGH DOMINATES THE GULF. AS OF 0900 UTC...A 1018 MB HIGH
IS CENTERED OVER THE NW CORNER OF THE GULF NEAR 29N93W. A SFC
TROUGH...PROBABLY REFLECTION OF AN UPPER TROUGH EXTENDS FROM
29N85W TO 25N87W. A STATIONARY FRONT LIES ACROSS NORTH FLORIDA.
SCATTERED SHOWERS AND ISOLATED TSTMS ARE ASSOCIATED WITH THE
TROUGH AXIS. DOPPLER RADAR SHOWS A LINE OF SHOWERS WITH EMBEDDED
TSTMS JUST OFF THE LOUISIANA COAST. MOSTLY LIGHT AND VARIABLE
WINDS ARE FOUND ACROSS THE GULF. IN THE UPPER LEVELS...A DEEP
LAYERED TROUGH OVER THE EASTERN U.S. DIGS INTO THE EASTERN GULF.
THE BASE OF THE TROUGH REACHES THE YUCATAN PENINSULA AND WESTERN
CUBA. WV IMAGERY SHOWS AN UPPER LEVEL LOW ALONG THE TROUGH AXIS
CENTERED NEAR 22N88W. THIS TROUGH IS HELPING TO GENERATE SHOWERS
AND TSTMS OVER THE STATE OF FLORIDA AND WESTERN CUBA...AND
SUPPORTS THE AFOREMENTIONED FRONT. A BROAD UPPER LEVEL HIGH IS
INLAND OVER NW MEXICO WITH THE UPPER RIDGE COVERING THE GULF W
OF 90W.NLY UPPER LEVEL WINDS ARE OBSERVED IN THIS REGION. WEAK
PRES PATTERN WILL CONTINUE TO DOMINATE THE GULF THROUGH TUE.

CARIBBEAN SEA...
THE PRES GRADIENT BETWEEN THE ATLANTIC RIDGE AND THE LOW PRES
OVER COLOMBIA IS PRODUCING MODERATE TRADE WINDS OF 15 TO 20 KT
ACROSS THE SOUTH-CENTRAL CARIBBEAN. A TROPICAL WAVE IS ALONG 80W
PRODUCING CONVECTION IN THE AREA. SEE ABOVE. SCATTERED MODERATE
CONVECTION IS INLAND OVER PARTS OF CENTRAL AMERICA AND NORTHERN
COLOMBIA WHERE A 1011 MB LOW IS ANALYZED ON THE O600 UTC SFC
MAP. ALOFT...THE UPPER LEVEL LOW OVER THE SE GULF OF MEXICO IS
PRODUCING SWLY FLOW OVER THE NW CARIBBEAN SEA AND CUBA. AN UPPER
LEVEL HIGH IS CENTERED MIDWAY BETWEEN JAMAICA AND COLOMBIA
ENHANCING THE CONVECTION RELATED TO THE TROPICAL WAVE WHILE
ANOTHER UPPER LEVEL HIGH IS OVER THE NE CARIBBEAN ALSO
SUPPORTING THE CONVECTION ASSOCIATED WITH THE WAVE CURRENTLY
MOVING ACROSS THE LEEWARD ISLANDS. UPPER DRY AIR COVERS MOST OF
THE E CARIBBEAN AND N VENEZUELA.

ATLANTIC OCEAN...
AS IS TYPICAL FOR THIS TIME OF THE YEAR...THE AZORES HIGH WITH A
1034 MB CENTER NEAR 39N43W DOMINATES MOST OF THE ATLANTIC OCEAN
WITH MAINLY FAIR WEATHER. ONLY PATCHES OF LOW/MID CLOUDS ARE
SEEN UNDER THE INFLUENCE OF THIS SYSTEM. PRES GRADIENT BETWEEN
THE AZORES HIGH AND A BROAD AREA OF LOW PRES JUST SOUTH OF THE
AZORES ASSOCIATED WITH A TROPICAL WAVE IS PRODUCING A SWATH OF
20 TO 25 KT NELY WINDS FROM 20N TO 30N EAST OF 45W. ALOFT...A
WELL DEFINED UPPER LEVEL LOW IS NEAR 30N67W. A LARGE AREA OF
CLOUDINESS AND SHOWERS...EXTENDING FROM THE SOUTHEASTERN BAHAMAS
NORTHEASTWARD INTO THE ATLANTIC IS ASSOCIATED WITH THIS
UPPER-LEVEL LOW. THIS SYSTEM HAS CHANGED LITTLE OVERNIGHT AND
REMAINS POORLY ORGANIZED. ENVIRONMENTAL CONDITIONS...HOWEVER...
COULD BECOME A LITTLE MORE FAVORABLE FOR SOME DEVELOPMENT OVER
THE NEXT DAY OR TWO. A CUT-OFF LOW IS OVER THE CENTRAL ATLC NEAR
24N50W. A RIDGE EXTENDS FROM W AFRICA INTO THE E ATLC E OF 26W.

$$
GR






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