000 AXNT20 KNHC 212345 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 705 PM EST WED NOV 21 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 1800 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 2315 UTC. ...TROPICAL WAVES... A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 83W/84W SOUTH OF 19N MOVING WEST 10 KT. A TROPICAL WAVE IS ALONG 83W/84W SOUTH OF 18N. THE WAVE IS MOVING THROUGH AN AREA OF BROAD SURFACE LOW PRESSURE. SCATTERED STRONG SHOWERS/THUNDERSTORMS FROM 10N TO 11N BETWEEN 80W AND 81W. OTHER SHOWERS/POSSIBLE THUNDERSTORMS ARE SOUTH OF 13N72W 14N80W 17N85W...AND FROM 18N TO 20N BETWEEN 82W AND 86W. AN ATLANTIC OCEAN TROPICAL WAVE WAS ALONG 46W SOUTH OF 17N MOVING WEST 10 TO 15 KT. ISOLATED MODERATE SHOWERS FROM 10N TO 20N BETWEEN 40W AND 50W. ...THE ITCZ... IT GOES FROM 8N12W 5N19W 5N37W 4N50W...CROSSING THE CENTRAL SECTION OF FRENCH GUIANA INTO EASTERN SURINAME NEAR 4N55W. SCATTERED STRONG SHOWERS/THUNDERSTORMS WITHIN A 30 TO 40 NM RADIUS OF 5N42W. ISOLATED MODERATE SHOWER AND WEAKENING CONVECTIVE PRECIPITATION FROM 5N TO 8N BETWEEN 44W AND 46W. SCATTERED STRONG SHOWERS/THUNDERSTORMS FROM 4N TO 6N BETWEEN 30W AND 34W. ISOLATED MODERATE SHOWERS WITHIN A 30 NM RADIUS OF 10N44W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 1N TO 6N BETWEEN 20W AND 30W. BROKEN TO OVERCAST HIGH CLOUDS ARE MOVING NORTHEASTWARD FROM 13N35W...ACROSS THE CAPE VERDE ISLANDS. DISCUSSION... THE GULF OF MEXICO... A DEEP LAYER TROUGH IS MOVING THROUGH THE CENTRAL U.S.A... RIGHT NOW FROM CENTRAL MEXICO TO WEST TEXAS. THIS TROUGH IS SUPPORTING A COLD FRONT FROM NORTHEASTERN TEXAS TO SOUTH CENTRAL TEXAS AND CURVING TO WEST TEXAS. LINES OF SHOWERS/THUNDERSTORMS ARE IN TEXAS AND LOUISIANA. UPPER LEVEL ANTICYCLONIC FLOW FROM A RIDGE SPANS PRACTICALLY ALL THE GULF OF MEXICO...EXCEPT FOR A SMALL PART OF THE APPROACHING DEEP LAYER TROUGH. A SURFACE RIDGE PASSES THROUGH 32N73W TO A 1023 MB HIGH PRESSURE CENTER NEAR 30N77W TO THE CENTRAL GULF OF MEXICO...TO THE WESTERN AND SOUTHWESTERN SECTIONS OF THE GULF OF MEXICO. THE CARIBBEAN SEA... UPPER LEVEL ANTICYCLONIC WIND FLOW MOVES FROM INTERIOR SOUTH AMERICA NORTHWARD TO THE SOUTHERN CARIBBEAN SEA EAST OF 80W. THIS AREA OF ANTICYCLONIC FLOW GOES AS FAR NORTH AS 13N. THE UPPER LEVEL FLOW SPLITS AS IT PASSES OVER PANAMA AND MOVES TOWARD THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. ONE RIDGE THEN IS OVER SOUTH AMERICA AND THE CARIBBEAN WATERS SOUTH OF 13N...AND A SECOND RIDGE COVERS THE AREA FROM THE SOUTHWESTERN CARIBBEAN SEA INTO THE NORTHWESTERN CORNER OF THE AREA. A 200 MB RIDGE IS SUPER-IMPOSED ON A 500 MB ANTICYCLONIC CIRCULATION CENTER THAT IS ABOUT 250 NM TO WEST-SOUTHWEST OF JAMAICA. THE REST OF THE CARIBBEAN SEA...ROUGHLY NORTH OF 13N BETWEEN 60W AND 80W...IS COVERED BY DEEP LAYER CYCLONIC FLOW. THE CYCLONIC FLOW IS COURTESY OF A DEEP LAYER TROUGH THAT STARTS IN THE CENTRAL ATLANTIC OCEAN AND REACHES THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA. MIDDLE TO UPPER LEVEL DRY AIR IS MOVING THROUGH/ACROSS THE CARIBBEAN SEA AND COVERS THE AREA NORTH OF 16N BETWEEN 60W AND JAMAICA/CUBA NEAR 78W. A TROPICAL WAVE IS ALONG 83W/84W SOUTH OF 18N. THE WAVE IS MOVING THROUGH AN AREA OF BROAD SURFACE LOW PRESSURE. SCATTERED STRONG SHOWERS/ THUNDERSTORMS FROM 10N TO 11N BETWEEN 80W AND 81W. OTHER SHOWERS/ POSSIBLE THUNDERSTORMS ARE SOUTH OF 13N72W 14N80W 17N85W...AND FROM 18N TO 20N BETWEEN 82W AND 86W. THE ATLANTIC OCEAN... A DEEP LAYER CENTRAL ATLANTIC OCEAN TROUGH IS THE MAIN FEATURE. THE TROUGH PASSES THROUGH 32N53W TO 25N60W TO THE NORTHEASTERN CARIBBEAN SEA NEAR 18N64W TO THE WATERS JUST SOUTH OF SOUTHWESTERN HAITI. MIDDLE TO UPPER LEVEL DRY AIR IS NORTH OF 16N BETWEEN 60W AND 78W IN THE CARIBBEAN SEA...AND NORTH OF 20N WEST OF 60W ELSEWHERE. THE COLD FRONT SUPPORTED BY THIS TROUGH PASSES THROUGH 32N45W 26N47W 20N55W 19N60W TO PUERTO RICO. SCATTERED STRONG SHOWERS/THUNDERSTORMS ARE NORTH OF 29N BETWEEN 38W AND 41W. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS/ POSSIBLE THUNDERSTORMS WITHIN 180 NM ON EITHER SIDE OF 29N40W 24N46W...AND WITHIN 120 NM ON EITHER SIDE OF 24N46W 21N50W 18N55W. ONE SURFACE RIDGE GOES FROM A 1023 MB HIGH PRESSURE CENTER NEAR 30N77W TO 24N68W 21N62W 21N56W. BROAD SURFACE ANTICYCLONIC FLOW IS AROUND A 1020 MB HIGH PRESSURE CENTER NEAR 25N34W. $$ MT