000 AXNT20 KNHC 171805 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 205 PM EDT THU JUL 17 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 1715 UTC. ...SPECIAL FEATURES... THE CENTER OF TROPICAL STORM BERTHA AT 17/1500 UTC IS NEAR 34.2N 58.4W MOVING SOUTHEAST 8 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 997 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 50 KT WITH GUSTS TO 60 KT. 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. THE FORECAST IS FOR BERTHA TO WEAKEN SLIGHTLY DURING THE NEXT 48 HOURS...AND THEN TO BECOME AN EXTRATROPICAL STORM AT 72 HOURS. STRONG SHOWERS AND THUNDERSTORMS FROM 33N TO 35N BETWEEN 56W AND 58W IN THE EASTERN SEMICIRCLE. A WESTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 82W SOUTH OF 22N MOVING WEST 15 KT...SLOWING DOWN COMPARATIVELY DURING THE LAST SIX HOURS OR SO. A 1011 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 13.5N. THE SURFACE TO LOW LEVEL CYCLONIC FLOW AND SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS AROUND THIS SYSTEM COVER THE CARIBBEAN SEA FROM PANAMA AND COSTA RICA TO 20N BETWEEN 76W AND 85W IN HONDURAS/NICARAGUA/COSTA RICA. CLOUDS AND PRECIPITATION ALREADY ARE REACHING NICARAGUA AND HONDURAS AT THIS TIME. EXPECT THIS PRECIPITATION TO AFFECT CENTRAL AMERICA DURING THE NEXT 24 HOURS OR SO AS LONG AS THE CURRENT PRECIPITATION REMAINS INTACT. THIS PRECIPITATION MAY CAUSE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES. THIS SYSTEM HAS CHANGED LITTLE IN ORGANIZATION SINCE YESTERDAY. THE SYSTEM HAS A CHANCE TO BECOME A TROPICAL DEPRESSION BEFORE IT REACHES THE COAST OF CENTRAL AMERICA TONIGHT. AN EASTERN CARIBBEAN SEA TROPICAL WAVE IS ALONG 63W/64W SOUTH OF 19N MOVING WEST ABOUT 20 KT. A 1009 MB LOW PRESSURE CENTER IS ALONG THE WAVE NEAR 13N. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS EXPECTED TO INVESTIGATE THE CONDITIONS AROUND THIS WAVE AROUND 17/1800 UTC. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE FROM 12N TO 14N BETWEEN 64W AND 69W. ISOLATED MODERATE SHOWERS ARE ELSEWHERE SOUTH OF 15N BETWEEN 60W AND 70W. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 43W/44W SOUTH OF 18N MOVING WEST 15 TO 20 KT. THIS WAVE IS COMPARATIVELY MUCH LESS EVIDENT IN THE VISIBLE SATELLITE THAN THE OTHER TWO WAVES. NO DEEP CONVECTIVE PRECIPITATION ACCOMPANIES THIS WAVE. ...THE ITCZ... 10N14W 5N23W 10N42W 8N53W 11N61W. SCATTERED STRONG SHOWERS AND THUNDERSTORMS FROM 10N TO 12N BETWEEN 15W AND 17W IN COASTAL WATERS/COASTAL PLAINS OF GUINEA-BISSAU AND GUINEA. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ALSO ARE WITHIN 15 TO 30 NM ON EITHER SIDE OF 8N19W 7N22W 6N24W 5N27W. ISOLATED MODERATE SHOWERS TO LOCALLY STRONG THUNDERSTORMS FROM 6N TO 11N BETWEEN 47W AND 61W IN THE WATERS JUST NORTH OF NORTHEASTERN SOUTH AMERICA. ...DISCUSSION... THE GULF OF MEXICO... A MIDDLE TO UPPER LEVEL TROUGH EXTENDS FROM SOUTHWESTERN ALABAMA TO SOUTHEASTERN LOUISIANA TO THE GULF OF MEXICO WATERS NEAR 27N95W TO COASTAL MEXICO NEAR 23N99W THROUGH THE ISTHMUS OF TEHUANTEPEC INTO THE EASTERN PACIFIC OCEAN. LIGHT SHOWERS... SOME DISSIPATING WITH TIME...ARE FROM 28N TO 30N BETWEEN 87W AND 92W. A TROUGH EXTENDS FROM A 1013 MB LOW PRESSURE CENTER NEAR 30N81W...ACROSS FLORIDA TO 23N83W. A SECOND SURFACE TROUGH EXTENDS FROM A 1015 MB LOW PRESSURE CENTER 25N87W TO 23N90W AND 26N95W. CLOUDS AND SHOWERS ARE FROM 22N TO 27N BETWEEN 88W AND 96W. THE CARIBBEAN SEA... ONE TROPICAL WAVE IS ALONG 82W. THE PRECIPITATION ACCOMPANYING THE 82W TROPICAL WAVE ALREADY IS REACHING NICARAGUA AND HONDURAS. THIS PRECIPITATION MAY CAUSE LIFE-THREATENING FLASH FLOODS AND MUDSLIDES. THIS SYSTEM HAS CHANGED LITTLE IN ORGANIZATION SINCE YESTERDAY...AND IT HAS A CHANCE TO BECOME A TROPICAL DEPRESSION BEFORE IT REACHES THE COAST OF CENTRAL AMERICA TONIGHT. A SECOND TROPICAL WAVE IS ALONG 63W/64W. AN AIR FORCE RECONNAISSANCE AIRCRAFT IS EXPECTED TO INVESTIGATE THE CONDITIONS AROUND THIS WAVE DURING THE NEXT FEW HOURS. THE PRECIPITATION WITH THIS WAVE MOSTLY IS IN THE SOUTHEASTERN CARIBBEAN SEA WATERS...SOME OF IT REACHING THE CARIBBEAN SEA ISLANDS SOUTH OF 15N AND THE NETHERLANDS ANTILLES...BUT STILL MOSTLY AWAY FROM MAINLAND SOUTH AMERICA. THE BASE OF A MIDDLE TO UPPER LEVEL TROUGH REACHES THE SOUTHEASTERN CORNER OF THE AREA NEAR 14N61W JUST EAST OF THE TROPICAL WAVE. THE ATLANTIC OCEAN... SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS ARE FROM 29N TO 32N BETWEEN 76W AND 80W IN AN AREA OF MIDDLE TO UPPER LEVEL DIFFLUENT FLOW. ISOLATED MODERATE SHOWERS EXTEND FROM COASTAL SOUTHEASTERN GEORGIA NEAR 32N81W TO NORTHEASTERN FLORIDA TO WESTERN FLORIDA FROM 27N TO 29N IN AN AREA OF UPPER LEVEL ANTICYCLONIC FLOW ON TOP OF MIDDLE LEVEL CYCLONIC FLOW. A MIDDLE TO UPPER LEVEL TROUGH ALONG 27N71W 24N75W 21N78W 20N81W IS SURROUNDED BY DRY AIR IN SUBSIDENCE. THIS TROUGH EXTENDS FROM THE ATLANTIC OCEAN TO THE SOUTHERN BAHAMAS TO CUBA...AND INTO THE NORTHWESTERN CARIBBEAN SEA. A MIDDLE TO UPPER LEVEL TROUGH IS CONNECTED BY ONE CYCLONIC CIRCULATION CENTER NEAR 24N46W TO 19N48W TO A SECOND CYCLONIC CENTER NEAR 16N57W TO 14N61W IN THE EASTERN CARIBBEAN SEA. THIS TROUGH IS EMBEDDED IN/SURROUNDED BY DRY AIR IN SUBSIDENCE. AN UPPER LEVEL RIDGE IS ALONG 16N36W 25N37W BEYOND 33N36W. $$ MT