[Tropical] Tropical Weather Discussion

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AXNT20 KNHC 171757
TWDAT

TROPICAL WEATHER DISCUSSION
NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
205 PM EDT THU MAY 17 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 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY
THROUGH 1715 UTC.

...THE ITCZ...

THE INTERTROPICAL CONVERGENCE ZONE IS ALONG THE LINE...5N10W
6.5N35W 3N51W AT THE EXTREME NORTHEAST PART OF BRAZIL.  THE IS
NOT MUCH CONVECTION ALONG THE ITCZ. ISOLATED MODERATE SHOWERS
AND POSSIBLE THUNDERSTORMS ARE WITHIN 120 NM OF THE AFRICAN
COAST FROM 8W TO 11W AND ARE ALSO WITHIN 60 TO 120 NM ON EITHER
SIDE OF 7.3N30W TO 1.5N50W. SCATTERED THUNDERSTORMS ARE WITHIN
120 NM OF THE SOUTH AMERICAN COAST FROM 52W TO 55W.

...DISCUSSION...

THE GULF OF MEXICO...
A MIDDLE TO UPPER LEVEL TROUGH THAT ORIGINATES IN THE
MISSISSIPPI VALLEY AREA OF THE U.S.A. REACHES THE GULF OF MEXICO
AND COVERS THE AREA WITH A BROAD TROUGH.  THIS TROUGH SUPPORTS A
COLD FRONT FROM NORTH FLORIDA TO SOUTH TEXAS. ISOLATED MODERATE
SHOWERS ARE NORTH OF 26N MAINLY EAST OF 88W. AN ISOLATED
THUNDERSTORM IS NEAR 25N85.4W. A WEAK SURFACE PRESSURE GRADIENT
COVERS THE REST OF THE GULF OF MEXICO AWAY FROM THE FRONT.

THE CARIBBEAN SEA...
A UPPER LEVEL TROUGH EXTENDS FROM CUBA NEAR 21N78W TO NEAR THE
NICARAGUA/HONDURAS BORDER. A WEAK LOW IS ANALYZED NEAR 18N83W
1013 MB AND THIS IS EXPECTED TO BE STATIONARY AND DEVELOP LITTLE
IN THE NEXT 24 HOURS. SCATTERED MODERATE SHOWERS AND
THUNDERSTORMS EXTENDS ABOUT 240 NM SOUTHEAST OF THE TROUGH.
SCATTERED SHOWERS AND THUNDERSTORMS ARE ALSO SOUTH OF 11.5N WEST
OF 76W. HIGH CLOUDS ARE SOUTH OF 16N W OF 70W. BROAD AND DRY
UPPER LEVEL NORTHWESTERLY WIND FLOW COVERS THE NORTHWEST PART
NORTH OF 16N WEST OF 80W.


THE ATLANTIC OCEAN...
A TROUGH EXTENDS FROM NEAR 32N72W TO A WEAK LOW NEAR GRAND
BAHAMA ISLAND AND CONTINUES INTO THE NORTHWESTERN CARIBBEAN.
SCATTERED SHOWERS AND THUNDERSTORMS ARE EAST OF THE TROUGH TO
NEAR 68W NORTH OF 22N. THE LOW IS EXPECTED TO MOVE NORTH OF 31N
IN 24 HOURS AND DEVELOP INTO A GALE NORTH OF 32N.

A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM A CYCLONIC
CIRCULATION CENTER NEAR 28N49W TO 19N50W. THIS TROUGH SUPPORTS
THE ATLANTIC OCEAN STATIONARY TROUGH THAT PASSES THROUGH 32N45W
TO 21N52W.  SCATTERED MODERATE SHOWERS WITHIN 300 NM EAST OF THE
TROUGH NORTH OF 20N. A SURFACE RIDGE EXTENDS SOUTH INTO THE AREA
THROUGH 32N33W TO 12N35W. ANOTHER RIDGE IS WEST OF THE TROUGH
THROUGH 32N57W TO 21N62W.

A FAR EASTERN ATLANTIC OCEAN MIDDLE TO UPPER LEVEL TROUGH IS
NORTH OF LINE 7N40W 15N30W 21N10W. DRY AIR IN THE MIDDLE AND
UPPER LEVELS IS WITHIN 300 NM NORTH OF THIS LINE.  UPPER LEVEL
MOISTURE IS ADVECTING OVER AFRICA WITHIN 400 NM SOUTH OF THE
LINE.

$$
LL




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