000 AXNT20 KNHC 171805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT TUE OCT 17 2006 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...THE GULF OF MEXICO...THE CARIBBEAN SEA...NORTHEASTERN 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...WEATHER OBSERVATIONS...RADAR... AND METEOROLOGICAL ANALYSIS. BASED ON 1200 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1715 UTC. ...SPECIAL FEATURE... A DEEP LAYER TROUGH COVERS THE AREA FROM THE ATLANTIC OCEAN THROUGH 32N58W TO 25N62W TO 20N64W TO 15N66W TO THE PENINSULA DE PARAGUANA ALONG THE NORTHWESTERN COAST OF VENEZUELA NEAR 12N70W. A COLD FRONT PASSES THROUGH 32N50W TO 30N51W. A SURFACE TROUGH CONTINUES FROM 30N51W TO 25N60W TO 22N64W TO A 1008 MB LOW PRESSURE CENTER NEAR 20N66W. A TROUGH GOES FROM THE LOW PRESSURE CENTER ACROSS CENTRAL PUERTO RICO TO 15N68W. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 65W/66W SOUTH OF 18N MOVING WEST 10 TO 15 KT. THIS WAVE IS MOVING INTO THE AREA ALREADY OCCUPIED BY A DEEP LAYER TROUGH. THIS TROUGH RUNS FROM THE WESTERN ATLANTIC OCEAN...ACROSS PUERTO RICO...AND INTO THE SOUTHEASTERN CARIBBEAN SEA. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 12N TO 18N BETWEEN 62W AND 68W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 20N TO 22N BETWEEN 61W AND 64W AT THE EDGE OF THE NORTHEASTERN CORNER OF THE CARIBBEAN SEA. ISOLATED MODERATE SHOWERS ARE ELSEWHERE FROM 11N TO 17N BETWEEN 70W AND 80W IN UPPER LEVEL DIFFLUENT FLOW. UPPER LEVEL WINDS ARE NOT CONDUCIVE FOR TROPICAL CYCLONE DEVELOPMENT. IT IS LIKELY THAT THIS SYSTEM WILL PRODUCE LOCALLY HEAVY RAINFALL OVER SECTIONS OF PUERTO RICO... THE VIRGIN ISLANDS...AND THE LEEWARD ISLANDS DURING THE NEXT FEW DAYS AS IT MOVES SLOWLY SOUTHWESTWARD. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 36W/37W SOUTH OF 18N MOVING WEST 10 TO 15 KT. UPPER LEVEL SOUTHWESTERLY WIND FLOW IS MOVING ACROSS THE AREA OF THE WAVE ON THE SOUTH AND SOUTHEASTERN SIDE OF A MIDDLE TO UPPER LEVEL CENTRAL ATLANTIC OCEAN TROUGH. ISOLATED MODERATE SHOWERS AND POSSIBLE THUNDERSTORMS ARE FROM THE EQUATOR TO 10N BETWEEN 30W AND 38W. POSSIBLE SHOWERS FROM 10N TO 16N BETWEEN 30W AND 40W. A TROPICAL WAVE IS ALONG 93W/94W SOUTH OF 18N MOVING WEST 10 TO 15 KT. THE NORTHERN PART OF THIS WAVE IS MOVING THROUGH THE ISTHMUS OF TEHUANTEPEC. THE REST OF THE WAVE IS IN THE EASTERN PACIFIC OCEAN. NO DEEP CONVECTIVE PRECIPITATION IS OVER LAND AT THIS TIME. ...THE ITCZ... 11N12W 8N20W 6N30W 6N35W 6N38W 5N50W 5N54W. STRONG SHOWERS AND THUNDERSTORMS FROM 13N TO 15N BETWEEN 24W AND 25W. WIDELY SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 4N TO 10N BETWEEN 25W AND 30W. OTHER SHOWERS AND THUNDERSTORMS ALSO ARE POSSIBLE FROM 10N TO 18N BETWEEN 20W AND 30W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 10N TO 12N BETWEEN 39W AND 51W. ...DISCUSSION... GULF OF MEXICO... AN UPPER LEVEL NORTH CENTRAL GULF OF MEXICO ANTICYCLONIC CIRCULATION HAS SPREAD ANTICYCLONIC FLOW IN THE UNITED STATES OF AMERICA FROM THE SOUTHEASTERN CORNER TO THE MIDDLE ATLANTIC STATES...INTO THE ATLANTIC OCEAN NORTH OF 20N WEST OF 67W... AND INTO A LARGE PART OF THE CARIBBEAN SEA...TO THE WEST OF A DEEP LAYER TROUGH THROUGH 20N64W TO 12N70W AT THE NORTHWESTERN VENEZUELA COAST. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS HAVE DEVELOPED NEAR A SQUALL LINE. THE SQUALL LINE IS ALONG 27N93W 29N90W 32N88W. SCATTERED TO NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE WITHIN 30 NM ON EITHER SIDE OF 29N90W 30N87W 32N84W. CARIBBEAN SEA... UPPER LEVEL ANTICYCLONIC FLOW COVERS THE CARIBBEAN SEA EVERYWHERE TO THE WEST OF THE DEEP LAYER TROUGH...FROM THE ATLANTIC OCEAN THROUGH 32N58W TO 20N64W TO THE NORTHWESTERN VENEZUELA COAST. MIDDLE TO UPPER LEVEL DRY AIR COVERS THE AREA TO THE WEST OF THE ATLANTIC OCEAN-TO-CARIBBEAN SEA TROUGH. THIS ANTICYCLONIC FLOW IS COURTESY OF A NORTH CENTRAL GULF OF MEXICO ANTICYCLONIC CIRCULATION CENTER. ATLANTIC OCEAN... UPPER LEVEL ANTICYCLONIC FLOW...AROUND A NORTH CENTRAL GULF OF MEXICO ANTICYCLONIC CIRCULATION CENTER...COVERS THE WESTERN ATLANTIC OCEAN WATERS NORTH OF 20N WEST OF 67W. AN UPPER LEVEL RIDGE PASSES THROUGH 22N45W TO 27N43W BEYOND 32N41W. A DEEP LAYER TROUGH AS SEEN ON WATER VAPOR IMAGERY PASSES THROUGH 32N22W TO 26N28W. A COLD FRONT PASSES THROUGH 34N10W TO 31N14W. A SEPARATE MIDDLE TO UPPER LEVEL TROUGH GOES FROM 23N27W TO 20N36W TO 16N49W. SOME MIDDLE TO UPPER LEVEL DRY AIR IS WITHIN 120 NM ON EITHER SIDE OF THE SEPARATE TROUGH BETWEEN 25W AND 49W. MIDDLE TO UPPER LEVEL DRY AIR IS UNDER THE RIDGE IS NORTH OF 17N BETWEEN 34W AND 50W. $$ MT