[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 200516
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 AM EDT FRI JUL 20 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 0000 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH
0445 UTC.

...TROPICAL WAVES...
TROPICAL WAVE IS TITLED FROM 18N38W 12N42W 4N45W MOVING W 15-20
KT. BROAD WAVE LOW LEVEL INVERTED-V CURVATURE COVERING THE AREA
FROM 35N-48N. SCATTERED SHOWERS ARE WITHIN THE ITCZ.

TROPICAL WAVE IS SLIGHTLY TILTED ALONG 20N64W 15N67W 9N67W
MOVING WNW NEAR 15 KT. WAVE AMPLITUDE HAS INCREASED OVER THE
PAST 24 HOURS WITH A INCREASE OF PRESSURE GRADIENT OVER THE N
PORTION OF THE WAVE. THIS SYSTEM DOES HAVE SOME POTENTIAL FOR
FURTHER DEVELOPMENT BUT IF IT DOES IT WILL BE SLOW TO OCCUR.
HEAVY RAIN WITH EMBEDDED THUNDERSTORMS HAVE ALSO INCREASED
COVERING THE AREA FROM 15N-24N BETWEEN 60W-66W INCLUDING THE
LEEWARD/VIRGIN ISLANDS AND WILL BE MOVING OVER PUERTO RICO AND
HISPANIOLA LATER TODAY.

...THE ITCZ...
ITCZ AXIS IS CENTERED ALONG 8N12W 7N19W 12N35W 7N53W 11N61W.
SCATTERED MODERATE/STRONG CONVECTION IS MOVING OFF AFRICA WITHIN
90/120 NM OF LINE FROM 9N16W TO WELL INLAND OVER GUINEA AFRICA
NEAR 10N14W. SCATTERED MODERATE/ISOLATED STRONG CONVECTION IS
WITHIN 90/120 NM OF THE AXIS E OF 17W TO JUST INLAND OVER SIERRA
LEONE AFRICA. SCATTERED THUNDERSTORMS ARE WITHIN 150/200 NM S OF
THE AXIS FROM 28W-42W.

...DISCUSSION...
GULF OF MEXICO...
UPPER LEVEL HIGH IS ALONG THE W GULF COAST NEAR THE TEXAS/MEXICO
BORDER WITH THE UPPER RIDGE COVERING THE GULF W OF 87W ENHANCING
ISOLATED SHOWERS/THUNDERSTORMS W OF 94W. SHORTWAVE UPPER TROUGH
EXTENDS FROM THE E COAST OF THE CAROLINAS ACROSS SE GEORGIA INTO
THE FAR NE GULF ALONG THE WEST COAST OF FLORIDA. THE CUT-OFF
UPPER LOW THAT REMAINS CLOSE TO THE CAYMAN ISLANDS COVERS THE
GULF S OF 25N E OF 86W INTO THE W ATLC GENERATING ISOLATED
SHOWERS/ THUNDERSTORMS OVER THE SAME AREA. OTHERWISE A WEAK
SURFACE RIDGE REMAINS ACROSS THE GULF FROM THE W ATLC WITH A
1018 MB HIGH OFF THE SE LOUISIANA COAST NEAR 27N90W.

CARIBBEAN SEA...
THE AREA OF FOCUS TONIGHT REMAINS THE TROPICAL WAVE OVER THE E
CARIBBEAN ESPECIALLY OVER THE LEEWARD/VIRGIN ISLANDS AS HEAVY
RAINS WITH EMBEDDED THUNDERSTORMS AND WILL MOVING ACROSS PUERTO
RICO AND HISPANIOLA LATER TODAY. OTHERWISE...AN ELONGATED
CUT-OFF UPPER LOW REMAINS CENTERED CLOSE TO THE CAYMAN ISLANDS
NEAR 19N83W COVERING THE AREA N OF 16N FROM 75W TO THE YUCATAN
PENINSULA GENERATING SCATTERED SHOWERS/ISOLATED THUNDERSTORMS
FROM N OF A LINE FROM BETWEEN JAMAICA AND E CUBA NEAR 19N78W TO
THE YUCATAN PENINSULA NEAR 21N87W. BROAD UPPER HIGH IS CENTERED
OVER THE FAR NE CARIBBEAN NEAR 17N64W COVERING THE E CARIBBEAN E
OF 73W AND EXTENDS INTO THE W TROPICAL ATLC AND CENTRAL ATLC.
DRY STABLE AIR IS TO THE E OF THE UPPER HIGH COVERING THE
CARIBBEAN W OF 70W. THE ITCZ AXIS IN THE E PACIFIC REGION
EXTENDS ACROSS PANAMA AND COSTA RICA GENERATING SCATTERED
SHOWERS/THUNDERSTORMS S OF 10N FROM COLOMBIA TO COSTA RICA.
MODERATE/STRONG EASTERLY TRADE WINDS CONTINUE ACROSS THE
CARIBBEAN S OF 17N.

ATLANTIC OCEAN...
SHORTWAVE UPPER TROUGH EXTENDS FROM THE E COAST OF THE CAROLINAS
ACROSS SE GEORGIA INTO THE FAR NE GULF ALONG THE WEST COAST OF
FLORIDA AND EXTENDS OVER THE W ATLC N OF 27N W OF 77W. CUT-OFF
UPPER LOW CLOSE TO THE CAYMAN ISLANDS COVERS THE SW ATLC S OF
25N W OF 75W GENERATING ISOLATED SHOWERS S OF 25N W OF 79W INTO
THE STRAITS OF FLORIDA. AN UPPER LOW REMAINS IN THE NW ATLC NEAR
26N68W COVERING THE AREA N OF 22N FROM 62W-73W WITH A WEAKENING
SURFACE TROUGH EXTENDING FROM 31N65W TO 25N67W. UPPER HIGH IN
THE NE CARIBBEAN COVERS THE CENTRAL ATLC S OF 23N FROM 50W-68W
JUST TO THE S OF THE UPPER LOW MENTIONED ABOVE. THIS IS
ENHANCING THE THE HEAVY RAINS AND THUNDERSTORMS ASSOCIATED WITH
THE TROPICAL WAVE OVER THE E CARIBBEAN. A CUT-OFF UPPER LOW IS
CENTERED IN THE CENTRAL ATLC NEAR 25N49W COVERING THE AREA N OF
17N FROM 40W-55W WITH A VERY NARROW UPPER RIDGE BETWEEN THIS
UPPER LOW AND THE UPPER LOW CENTERED NEAR 26N68W GENERATING
SCATTERED SHOWERS/ISOLATED THUNDERSTORMS FROM 25N-31N BETWEEN
47W-64W. UPPER RIDGE EXTENDS OFF THE COAST OF AFRICA OVER THE E
ATLC E OF 35W. THE LAST VISIBLE SATELLITE IMAGES OF THE
YESTERDAY CONTINUE TO SHOW A LARGE AREA OF AFRICAN DUST OVER THE
E ATLC S OF A LINE FROM MOROCCO NEAR 33N9W ALONG 30N24W 25N43W
TO 21N55W WITH SOME CLEARING S OF 17N E OF 40W. THE REMAINDER OF
THE ATLC CONTINUES TO BE DOMINATED BY A SURFACE RIDGE ANCHORED
BY A 1033 MB HIGH CENTERED N OF THE REGION TO OVER THE N GULF OF
MEXICO.

$$
WALLACE




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