000 AXNT20 KNHC 171756 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM 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