000 AXNT20 KNHC 171805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT FRI AUG 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. ...SPECIAL FEATURE... THE CENTER OF HURRICANE DEAN AT 16/1800 UTC WAS NEAR 14.8N 63.6W OR ABOUT 152 NM/280 KM WEST OF MARTINIQUE...AND ABOUT 260 NM/ 480 KM SOUTHEAST OF SAN JUAN PUERTO RICO. HURRICANE DEAN WAS MOVING WEST 19 KT. THE MAXIMUM SUSTAINED WIND SPEEDS WERE NEAR 110 KT WITH GUSTS TO 135 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 961 MB. DEAN IS A CATEGORY THREE MAJOR HURRICANE. PLEASE SEE THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT4/WTNT24 KNHC OR THE LATEST PUBLIC ADVISORY UNDER MIATCPAT4/WTNT34 KNHC FOR MORE DETAILS. HURRICANE DEAN IS NOW A CATEGORY THREE HURRICANE...A MAJOR HURRICANE. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 13.5N TO 15.5N BETWEEN 62.5W AND 64W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS ARE IN A BAND TO THE EAST FROM 12.5N TO 16N BETWEEN 59W AND 62W. TO 15N BETWEEN 53W AND 58W. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 13N TO 15N BETWEEN 64W AND 65W...AND FROM 12N TO 14N BETWEEN 66W AND 67W. THE CENTER OF DEAN CROSSED THE LESSER ANTILLES THIS MORNING BETWEEN ST. LUCIA AND MARTINIQUE AS INDICATED BY THE MARTINIQUE RADAR. THE METEOROLOGICAL SERVICE OF MARTINIQUE REPORTED SUSTAINED WINDS OF 66 KNOTS WITH GUSTS TO 90 KNOTS AT 17/0842 UTC. AN AIR FORCE PLANE REACHED THE HURRICANE AND MEASURED A MINIMUM PRESSURE OF 964 MB...FLIGHT LEVEL WINDS OF 100 KNOTS...AND A CLOSED EYEWALL. THE CLOUD PATTERN HAS BECOME BETTER ORGANIZED SINCE YESTERDAY WITH PLENTY OF BANDING FEATURES AND OUTFLOW IN ALL QUADRANTS. THE LATEST VISIBLE IMAGE SHOWS AN EYE FEATURE. BOTH SATELLITE PRESENTATION AND DATA FROM THE MFR ON THE PLANE SUPPORT AN INITIAL INTENSITY OF 90 KNOTS. THE OFFICIAL INTENSITY FORECAST CALLS FOR STRENGTHENING SINCE GUIDANCE SUGGESTS THAT THE SHEAR WILL BE LOW ACROSS THE CARIBBEAN SEA. IT IS POSSIBLE THAT DEAN MAY BECOME A DANGEROUS HURRICANE WHEN IT REACHES THE WESTERN CARIBBEAN SEA WHERE THE OCEAN HEAT CONTENT IS THE HIGHEST. ...TROPICAL WAVES... THE TROPICAL WAVE INTRODUCED INTO THE SURFACE MAP ANALYSIS 24 HOURS AGO ALREADY HAS REACHED 32W SOUTH OF 19N AS OF 17/1700 UTC. THIS WAVE IS FORECAST TO REACH 41W OR SO BY 18/1200 UTC. A 1009 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 14N. BROAD DEEP LAYER CYCLONIC FLOW SURROUNDS THE WAVE...SOUTH OF 21N BETWEEN AFRICA AND 35W. THE 14N LOW CENTER APPEARS TO BE WEAKENING WITH TIME ACCORDING TO THE LATEST VISIBLE SATELLITE IMAGES. NO DEEP CONVECTIVE PRECIPITATION. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 41W/42W SOUTH OF 20N MOVING WEST 15 KT. ISOLATED MODERATE SHOWERS FROM 8N TO 12N BETWEEN 41W AND 47W. A CARIBBEAN SEA TROPICAL WAVE IS ALONG 76W/77W SOUTH OF 19N MOVING WEST 15 KT. THIS WAVE PASSES OVER EASTERN JAMAICA. ISOLATED MODERATE SHOWERS FROM 14N TO 18N BETWEEN 78W AND 80W. ...THE ITCZ... FROM THE COAST OF AFRICA NEAR 15N16W TO 14N22W...TO 8N30W 8N38W 8N43W 10N55W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 7N TO 8N BETWEEN 26W AND 27W...AND FROM 7N TO 9N BETWEEN 30W AND 33W. ISOLATED TO WIDELY SCATTERED MODERATE SHOWERS WITHIN 150 NM ON EITHER SIDE OF 11N18W 9N24W...AND WITHIN 60 TO 90 NM ON EITHER SIDE OF 7N34W 5N38W 4N42W. FEW SHOWERS WITHIN 60 TO 120 NM ON EITHER SIDE OF 5N43W 7N49W 9N57W. DISCUSSION... THE GULF OF MEXICO... LARGE SCALE UPPER LEVEL ANTICYCLONIC FLOW COVERS THE AREA WEST OF 84W. T.D. ERIN'S INFLUENCE IS BEING FELT FOR ABOUT 240 NM EAST OF THE CENTER. THE REST OF THE ANTICYCLONIC FLOW IS LARGE SCALE AND INDEPENDENT OF T.D. ERIN. LARGE SCALE CYCLONIC FLOW AROUND THE ATLANTIC OCEAN 27N77W MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER COVERS THE ATLANTIC OCEAN/THE GULF OF MEXICO/ THE CARIBBEAN SEA NORTH OF 20N WEST OF 70W IN THE ATLANTIC OCEAN...EAST OF 84W IN THE GULF OF MEXICO. A TROUGH CONTINUES FROM CENTRAL CUBA SOUTHWESTWARD INTO THE CARIBBEAN SEA TO THE BORDERS OF EASTERN HONDURAS/NORTHEASTERN NICARAGUA. THE CARIBBEAN SEA... HURRICANE DEAN HAS ENTERED THE EASTERN CARIBBEAN SEA. STRONG SHOWERS AND THUNDERSTORMS IN GENERAL ARE FROM 11N TO 16.5N BETWEEN 58W AND 68W. HIGH CLOUDS SPIRALLING ANTICYCLONICALLY OUTWARD COVER THE ATLANTIC OCEAN AND CARIBBEAN SEA FROM 13N TO 21N BETWEEN 50W AND 68W. A MIDDLE TO UPPER LEVEL TROUGH CONTINUES FROM THE 27N77W CYCLONIC CENTER ACROSS CENTRAL CUBA SOUTHWESTWARD INTO THE CARIBBEAN SEA TO THE BORDERS OF EASTERN HONDURAS/NORTHEASTERN NICARAGUA. WARMING CLOUD TOP TEMPERATURES AND WEAKENING CONVECTIVE PRECIPITATION FROM 16N TO 18N BETWEEN 85W AND 87W. ISOLATED MODERATE SHOWERS FROM 16.5N TO 17.5N BETWEEN 88W AND 90W FROM BELIZE TO NORTHERN GUATEMALA. THE 76W/77W TROPICAL WAVE BRINGS SOME ISOLATED MODERATE SHOWERS WITH IT...SOUTHWEST OF JAMAICA. MIDDLE TO UPPER LEVEL DRY AIR IS IMMEDIATELY ALONG THE LEADING EDGE OF HURRICANE DEAN BETWEEN THE HIGH LEVEL CIRRUS TO THE WEST OF DEAN AND 74W. ISOLATED MODERATE SHOWERS ARE IN THE EASTERN COASTAL AREAS OF NICARAGUA. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 9N TO 10N BETWEEN 77W AND 78W...AND FROM THE PANAMA COAST TO 10N BETWEEN 80.5W AND 81.5W. OTHER POSSIBLE SHOWERS ARE SOUTH OF 11N WEST OF 76W. THE ATLANTIC OCEAN... MIDDLE TO UPPER LEVEL CYCLONIC FLOW AROUND THE 28N74W CENTER COVERS THE AREA NORTH OF 20N WEST OF 65W. WIDELY SCATTERED TO SCATTERED MODERATE SHOWERS AND ISOLATED STRONG THUNDERSTORMS FROM 22N TO 27N BETWEEN 70W AND 80W. ISOLATED MODERATE SHOWERS ARE IN CUBA ON THE ATLANTIC OCEAN SIDE EAST OF 77W. A SECOND AND EQUALLY WELL-DEFINED MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 27N49W IN THE CENTRAL ATLANTIC OCEAN. CYCLONIC FLOW IS NORTH OF 20N BETWEEN 40W AND 56W. A SHEAR AXIS IS ALONG THE LINE FROM 30N24W TO 25N34W TO 20N41W AND 17N46W. AN AREA OF BROAD DEEP LAYER CYCLONIC FLOW SURROUNDS A 28W/29W TROPICAL WAVE. THIS FLOW IS SOUTH OF 21N BETWEEN AFRICA AND 35W. A 1009 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 14N. THE LOW CENTER APPEARS TO BE WEAKENING WITH TIME ACCORDING TO THE LATEST VISIBLE SATELLITE IMAGES. THE LATEST VISIBLE IMAGES ALSO SHOW THAT THE WAVE HAS SHOT FORWARD TO 32W OR SO. THIS IS A FAST-MOVING WAVE...FORECAST TO REACH 41W OR SO BY 18/1200 UTC. $$ MT