000 AXNT20 KNHC 091820 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT WED JUL 09 2008 TROPICAL WEATHER DISCUSSION FOR NORTH AMERICA...CENTRAL AMERICA...GULF OF MEXICO...CARIBBEAN SEA...NORTHERN SECTIONS OF SOUTH AMERICA...AND 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 1745 UTC. ...SPECIAL FEATURE.... THE CENTER OF HURRICANE BERTHA AT 09/1500 UTC IS NEAR 24.2N 57.5W. IT IS MOVING WEST-NORTHWEST OR 300 DEGREES 10 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 987 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 65 KT WITH GUSTS TO 80 KT. THIS POSITION ALSO IS 478 NM/885 KM NORTHEAST OF THE NORTHERN LEEWARD ISLANDS...AND ABOUT 621 NM/1150 KM SOUTHEAST OF BERMUDA. PLEASE READ THE LATEST NHC FORECAST/ADVISORY UNDER AWIPS/WMO HEADERS MIATCMAT2/WTNT22 KNHC AND THE PUBLIC ADVISORY UNDER MIATCPAT2/WTNT32 KNHC FOR MORE DETAILS. STRONG SHOWERS AND THUNDERSTORMS ARE FROM 23N TO 26N BETWEEN 56W AND 58W. BROKEN TO OVERCAST MULTILAYERED CLOUDS AND OTHER PRECIPITATION COVER THE AREA FROM 22N TO 30N BETWEEN 50W AND 61W. A SEPARATE LINE OF CLOUDS AND POSSIBLE PRECIPITATION IS WITHIN 30 NM ON EITHER SIDE OF 16N63W IN THE EASTERN CARIBBEAN SEA TO 19N58W IN THE ATLANTIC OCEAN...TO 21N56W TO 25N55W. THE ATMOSPHERE APPEARS FAVORABLE FOR STRENGTHENING AND THE OCEAN IS PLENTY WARM. THE VARIOUS INTENSITY MODELS ARE NOT IN GOOD AGREEMENT ON HOW MUCH OR EVEN WHEN RE-INTENSIFICATION MIGHT OCCUR. BERTHA SHOULD CONTINUE A SLOW TURN NORTHWARD DURING THE NEXT 2 TO 3 DAYS AS A MID-TROPOSPHERIC ANTICYCLONE CURRENTLY NEAR BERMUDA IS FORECAST TO WEAKEN AND A 500 MB SHORTWAVE TROUGH MOVES OFF OF THE U.S.A. EAST COAST. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 30W/31W SOUTH OF 13N MOVING WEST NEAR 10 TO 15 KT. NEARBY PRECIPITATION IS IN THE ITCZ. AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 50W SOUTH OF 13N MOVING WEST 10 TO 15 KT. CYCLONIC FLOW IN THE LOW CLOUDS ON VISIBLE SATELLITE IMAGERY AND QUIK-SCAT DATA HELP TO CONFIRM THIS POSITION. NEARBY PRECIPITATION IS IN THE ITCZ. A SOUTHWESTERN GULF OF MEXICO TROPICAL WAVE IS ALONG 96W SOUTH OF 22N MOVING WEST 15 TO 20 KT. THIS WAVE IS MOVING THROUGH THE AREA OF A MIDDLE TO UPPER LEVEL TROUGH...AND ANOTHER AREA OF UPPER LEVEL NORTHWESTERLY WIND FLOW THAT CUTS ACROSS THE TOP OF THE AREA OF THE WAVE. SHOWERS AND THUNDERSTORMS ARE DEVELOPING FROM 19N TO 20N BETWEEN 95W AND 96W. ...THE ITCZ... 9N13W 10N21W 8N40W 7N59W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS FROM 4N TO 6N BETWEEN 21W AND 30W...AND FROM 7N TO 10N BETWEEN 53W AND 58W. ISOLATED MODERATE SHOWERS FROM 6N TO 10N BETWEEN 31W AND 44W. NUMEROUS STRONG SHOWERS AND THUNDERSTORMS FROM 11N TO 12N BETWEEN 15W AND 16W...IN GUINEA AND GUINEA-BISSAU...AND POSSIBLY SENEGAL. ...DISCUSSION... THE GULF OF MEXICO... MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW MOVES FROM THE ATLANTIC OCEAN WEST OF 74W AND NORTH OF 24N INTO THE GULF OF MEXICO... REACHING THE LOWER TEXAS GULF COAST. A MIDDLE TO UPPER LEVEL TROUGH COVERS THE SOUTHWESTERN GULF OF MEXICO...ON TOP OF A 96W TROPICAL WAVE. UPPER LEVEL NORTHWESTERLY WIND FLOW MOVES FROM INTERIOR MEXICO ACROSS THE SOUTHWESTERN GULF OF MEXICO...ACROSS THE YUCATAN PENINSULA SOUTH OF 20N...INTO THE NORTHWESTERN CARIBBEAN SEA. THE CARIBBEAN SEA... A MIDDLE TO UPPER LEVEL INVERTED TROUGH IS MOVING THROUGH THE NORTHWESTERN CORNER OF THE CARIBBEAN SEA. ISOLATED MODERATE SHOWERS AND SOME THUNDERSTORMS ARE FROM 20N TO 22N BETWEEN 84W AND 85W...MOVING FROM THE WESTERN TIP OF CUBA INTO THE YUCATAN CHANNEL. UPPER LEVEL NORTHWESTERLY WIND FLOW CUTS ACROSS THE TOP OF THE AREA OF THIS INVERTED TROUGH. MIDDLE LEVEL CYCLONIC FLOW/A TROUGH APPEARS TO BE CENTERED ALONG 70W SOUTH OF 15N. ISOLATED MODERATE SHOWERS ARE FROM 17N TO 19N BETWEEN 66W AND 71W...FROM PUERTO RICO TO THE WATERS SOUTH OF THE WESTERN DOMINICAN REPUBLIC IN AN AREA OF UPPER LEVEL DIFFLUENT FLOW. AN UPPER LEVEL RIDGE EXTENDS FROM 5N72W IN COLOMBIA TO 13N78W. SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE OCCURRING FROM 15N TO 17N BETWEEN 78W AND 83W ALSO IN UPPER LEVEL DIFFLUENT FLOW IN THE WESTERN CARIBBEAN SEA. STRONG SHOWERS AND THUNDERSTORMS ARE SOUTH OF 11N75W 13N84W...UNDER THE UPPER LEVEL RIDGE...NORTH OF THE ITCZ...WITH BROAD MIDDLE LEVEL CYCLONIC WIND FLOW. THE ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS NEAR 28N69W. CYCLONIC FLOW AROUND THIS CENTER COVERS THE ATLANTIC OCEAN FROM 24N TO 32N BETWEEN 65W AND 72W. A MIDDLE TO UPPER LEVEL TROUGH IS NORTHEAST OF THE AREA OF HURRICANE BERTHA...PASSING THROUGH 35N51W TO 32N54W. THIS TROUGH SUPPORTS A COLD FRONT THAT PASSES THROUGH 33N46W TO 31N49W. MODERATE SHOWERS ARE WITHIN 15 TO 30 NM ON EITHER SIDE OF 31N BETWEEN 43W AND 55W...AND NORTH OF 31N BETWEEN 40W AND 43W. A SURFACE RIDGE PASSES THROUGH A 1024 MB HIGH PRESSURE CENTER NEAR 33N63W TO THE FLORIDA PANHANDLE NEAR 31N86W INTO SOUTHERN LOUISIANA. A MIDDLE TO UPPER LEVEL TROUGH IS IN THE EASTERN ATLANTIC OCEAN PASSING THROUGH 32N28W TO 23N39W. A SURFACE RIDGE PASSES THROUGH 32N26W TO 29N32W TO 24N44W TO 16N52W. $$ MT