000 AXNT20 KNHC 121153 TWDAT TROPICAL WEATHER DISCUSSION NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL 805 AM EDT SAT JUL 12 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 0600 UTC SURFACE ANALYSIS AND SATELLITE IMAGERY THROUGH 1015 UTC. ...SPECIAL FEATURE.... A TROPICAL STORM WATCH REMAINS IN EFFECT FOR BERMUDA. IT IS LIKELY THAT A TROPICAL STORM WARNING WILL BE ISSUED FOR BERMUDA LATER TODAY. THE CENTER OF HURRICANE BERTHA AT 12/1200 UTC IS NEAR 29.7N 62.6W. IT IS MOVING NORTH-NORTHWEST OR 340 DEGREES 4 KT. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 976 MB. THE MAXIMUM SUSTAINED WIND SPEEDS ARE 80 KT WITH GUSTS TO 100 KT. THIS POSITION ALSO IS 190 NM/360 KM SOUTH-SOUTHEAST OF BERMUDA. THE CENTER OF BERTHA IS EXPECTED TO PASS SLOWLY TO THE SOUTHEAST AND EAST OF BERMUDA DURING THE NEXT COUPLE OF DAYS...BUT THE MOTION OCCASIONALLY MAY BE ERRATIC. 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. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS ARE FROM 28N TO 31N BETWEEN 60W AND 65W. THE INTENSITY FORECAST WILL KEEP BERTHA AT 80 KT FOR THE FIRST 24 HOURS...WEAKENING GRADUALLY AND FALLING BELOW HURRICANE-FORCE WINDS AFTER 72 HOURS. ...TROPICAL WAVES... AN ATLANTIC OCEAN TROPICAL WAVE IS ALONG 45W/46W SOUTH OF 15N MOVING WEST 15 KT. A LOW TO MIDDLE LEVEL CYCLONIC CIRCULATION CENTER IS ALONG THE WAVE NEAR 10.5N. SCATTERED STRONG SHOWERS AND THUNDERSTORMS IN INDIVIDUAL CLUSTERS FROM 10N TO 12N BETWEEN 46W AND 48W. A CENTRAL CARIBBEAN SEA TROPICAL WAVE IS ALONG 73W/74W SOUTH OF 18N MOVING WEST 15 KT. THIS WAVE STRETCHES FROM THE SOUTHWESTERN COAST OF HAITI TO THE NORTHERN COLOMBIA COAST. BROAD UPPER LEVEL ANTICYCLONIC WIND FLOW IS ON TOP OF WEAK MIDDLE LEVEL CYCLONIC FLOW IN THE AREA THROUGH WHICH THE WAVE IS MOVING. NO DEEP CONVECTIVE PRECIPITATION. ...THE ITCZ... 14N17W 9N33W 11N45W 6N60W IN NORTHERN GUYANA. WIDELY SCATTERED TO SCATTERED MODERATE SHOWERS TO ISOLATED STRONG THUNDERSTORMS IN AN AREA BOUNDED BY THE LINE FROM THE EQUATOR AT 28N TO 6N24W TO 1N38W TO THE EQUATOR AT 38W...AND FROM 7N TO 12N BETWEEN AFRICA AND 60W. ...DISCUSSION... THE GULF OF MEXICO... BROAD MIDDLE TO UPPER LEVEL ANTICYCLONIC FLOW COVERS THE ENTIRE AREA. MIDDLE TO UPPER LEVEL MOISTURE IS EAST OF 90W AND COMPARATIVELY MUCH DRIER AIR IN SUBSIDENCE IS WEST OF 90W. THE MIDDLE LEVEL CYCLONIC CIRCULATION CENTER/TROUGH IN THE COASTAL PLAINS OF TEXAS FROM 24 HOURS AGO HAS MOVED MORE AND MORE WESTWARD...A CYCLONIC CENTER IS NEAR 27N104W IN MEXICO. A MIDDLE TO UPPER LEVEL CYCLONIC CIRCULATION CENTER IS IN THE NORTHWESTERN CORNER OF THE YUCATAN PENINSULA. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH 32N80W IN COASTAL SOUTH CAROLINA TO NORTHERN FLORIDA NEAR 30N83W. A SURFACE RIDGE RUNS FROM A 1021 MB HIGH PRESSURE CENTER NEAR 27N85W TO EXTREME NORTHEASTERN COASTAL MEXICO JUST SOUTH OF THE LOWER TEXAS COAST. THE CARIBBEAN SEA... BROAD UPPER LEVEL ANTICYCLONIC FLOW CUTS INTO THE NORTHWESTERN CORNER ACROSS CUBA...FROM THE ATLANTIC OCEAN AND THE EASTERN GULF OF MEXICO. A MIDDLE TO UPPER LEVEL TROUGH PASSES THROUGH THE ATLANTIC OCEAN FROM A CYCLONIC CENTER NEAR 25N75W...ACROSS CUBA TO 19N80W. SHOWERS DEVELOP AND ALTERNATELY DISSIPATE NEAR THE TROUGH. ISOLATED MODERATE SHOWERS ARE IN THE WATERS NORTH OF HONDURAS IN UPPER LEVEL DIFFLUENT FLOW. AN UPPER LEVEL RIDGE IS ON TOP OF MIDDLE LEVEL CYCLONIC FLOW IN THE SOUTHWESTERN CORNER OF THE AREA. STRONG SHOWERS AND THUNDERSTORMS ARE EAST OF NICARAGUA AND IN SOUTHEASTERN NICARAGUA FROM 10N TO 13N BETWEEN 82W AND 85W...AND SOUTH OF 10N BETWEEN PANAMA AT 79W AND COSTA RICA. SHOWERS ARE WEAKENING SOUTH OF 10N BETWEEN COLOMBIA AND PANAMA AND IN THE GULF OF URABA. THE ATLANTIC OCEAN... A MIDDLE TO UPPER LEVEL TROUGH GOES FROM 32N72W TO A CYCLONIC CIRCULATION CENTER NEAR 25N75W TO 23N76W...ACROSS CUBA TO 19N80W A LITTLE BIT WEST OF JAMAICA. ISOLATED MODERATE SHOWERS ARE WITHIN 120 NM TO 180 NM ON EITHER SIDE OF TROUGH. DRY AIR IN SUBSIDENCE COVERS MUCH OF THE REST OF THE ATLANTIC WATERS NORTH OF THE ITCZ CLOUDS AND PRECIPITATION TO 30N BETWEEN 30W AND 70W. A DEEP LAYER TROUGH CONTINUES TO THE EAST-NORTHEAST OF HURRICANE BERTHA...FROM A CYCLONIC CIRCULATION CENTER NEAR 34N45W TO 25N46W. BROAD MIDDLE TO UPPER LEVEL CYCLONIC FLOW COVERS THE AREA NORTH OF 25N BETWEEN 34W AND 56W. A SURFACE TROUGH PASSES THROUGH 33N46W TO 31N47W. SCATTERED MODERATE TO STRONG SHOWERS AND THUNDERSTORMS FROM 30N TO 35N BETWEEN 44W AND 47W. A SURFACE RIDGE EXTENDS FROM A 1022 MB HIGH PRESSURE CENTER NEAR 29N73W TO THE NORTHEASTERN FLORIDA COAST NEAR 29N...AND EVENTUALLY TO THE GULF OF MEXICO 1021 MB HIGH PRESSURE CENTER NEAR 27N85W. BROAD SURFACE HIGH PRESSURE COVERS THE AREA NORTH OF 16N BETWEEN AFRICA AND 57W. $$ MT