Boletin 5:00pm Agosto 01, 2014 WTNT33 KNHC 012048 BULLETIN TROPICAL STORM BERTHA ADVISORY NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032014 500 PM AST FRI AUG 01 2014 ...CENTER OF BERTHA PASSING NEAR THE NORTHERN END OF MARTINIQUE... ...TROPICAL STORM WATCH ISSUED FOR THE SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS ISLANDS... SUMMARY OF 500 PM AST...2100 UTC...INFORMATION ---------------------------------------------- LOCATION...14.9N 61.2W ABOUT 20 MI...30 KM NW OF FORT DE FRANCE MARTINIQUE ABOUT 405 MI...650 KM SE OF SAN JUAN PUERTO RICO MAXIMUM SUSTAINED WINDS...50 MPH...85 KM/H PRESENT MOVEMENT...WNW OR 290 DEGREES AT 24 MPH...39 KM/H MINIMUM CENTRAL PRESSURE...1007 MB...29.74 INCHES WATCHES AND WARNINGS -------------------- CHANGES WITH THIS ADVISORY... THE GOVERNMENT OF THE BAHAMAS HAS ISSUED A TROPICAL STORM WATCH FOR THE SOUTHEASTERN BAHAMAS...INCLUDING THE ACKLINS...CROOKED ISLAND... LONG CAY...THE INAGUAS...MAYAGUANA...AND THE RAGGED ISLANDS...AS WELL AS FOR THE TURKS AND CAICOS ISLANDS. SUMMARY OF WATCHES AND WARNINGS IN EFFECT... A TROPICAL STORM WARNING IS IN EFFECT FOR... * DOMINICA * MARTINIQUE * PUERTO RICO * VIEQUES * CULEBRA * U.S. VIRGIN ISLANDS * BRITISH VIRGIN ISLANDS A TROPICAL STORM WATCH IS IN EFFECT FOR... * THE EASTERN DOMINICAN REPUBLIC FROM CABO FRANCES VIEJO TO ISLA SAONA * THE SOUTHEASTERN BAHAMAS...INCLUDING THE ACKLINS...CROOKED ISLAND...LONG CAY...THE INAGUAS...MAYAGUANA...AND THE RAGGED ISLANDS * THE TURKS AND CAICOS ISLANDS A TROPICAL STORM WARNING MEANS THAT TROPICAL STORM CONDITIONS ARE EXPECTED SOMEWHERE WITHIN THE WARNING AREA...IN THIS CASE WITHIN THE NEXT 24 HOURS. A TROPICAL STORM WATCH MEANS THAT TROPICAL STORM CONDITIONS ARE POSSIBLE WITHIN THE WATCH AREA...GENERALLY WITHIN 48 HOURS. INTERESTS ELSEWHERE ACROSS THE NORTHEASTERN CARIBBEAN SEA AND HISPANIOLA SHOULD MONITOR THE PROGRESS OF THIS SYSTEM. FOR STORM INFORMATION SPECIFIC TO YOUR AREA IN THE UNITED STATES...INCLUDING POSSIBLE INLAND WATCHES AND WARNINGS...PLEASE MONITOR PRODUCTS ISSUED BY YOUR LOCAL NATIONAL WEATHER SERVICE FORECAST OFFICE. FOR STORM INFORMATION SPECIFIC TO YOUR AREA OUTSIDE THE UNITED STATES...PLEASE MONITOR PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE. DISCUSSION AND 48-HOUR OUTLOOK ------------------------------ AT 500 PM AST...2100 UTC...THE CENTER OF TROPICAL STORM BERTHA WAS LOCATED NEAR LATITUDE 14.9 NORTH...LONGITUDE 61.2 WEST. BERTHA IS MOVING TOWARD THE WEST-NORTHWEST NEAR 24 MPH...39 KM/H...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT COUPLE OF DAYS. ON THE FORECAST TRACK...BERTHA IS EXPECTED TO MOVE AWAY FROM MARTINIQUE INTO THE NORTHEASTERN CARIBBEAN SEA DURING THE NEXT SEVERAL HOURS...PASS NEAR PUERTO RICO AND THE VIRGIN ISLANDS ON SATURDAY...PASS NEAR OR OVER THE EASTERN DOMINICAN REPUBLIC SATURDAY NIGHT...AND APPROACH THE SOUTHEASTERN BAHAMAS AND THE TURKS AND CAICOS ISLANDS ON SUNDAY. MAXIMUM SUSTAINED WINDS ARE NEAR 50 MPH...85 KM/H...WITH HIGHER GUSTS. BERTHA REMAINS IN AN ENVIRONMENT THAT IS NOT FAVORABLE FOR STRENGTHENING...AND LITTLE CHANGE IN STRENGTH IS FORECAST DURING THE NEXT 48 HOURS. TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 115 MILES...185 KM MAINLY TO THE NORTHEAST OF THE CENTER. A FRENCH WEATHER STATION ON LA DESIRADE ISLAND NEAR GUADELOUPE RECENTLY REPORTED SUSTAINED WINDS OF 35 MPH...56 KM/H...AND A WIND GUST OF 52 MPH...84 KM/H. THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1007 MB...29.74 INCHES. HAZARDS AFFECTING LAND ---------------------- WIND...TROPICAL STORM CONDITIONS ARE SPREADING ACROSS PORTIONS OF THE SOUTHERN LEEWARD ISLANDS IN THE WARNING AREA...MAKING OUTSIDE PREPARATIONS DIFFICULT OR DANGEROUS. TROPICAL STORM CONDITIONS ARE POSSIBLE ON GUADELOUPE DURING THE NEXT SEVERAL HOURS. TROPICAL STORM CONDITIONS ARE EXPECTED IN PUERTO RICO AND THE VIRGIN ISLANDS ON SATURDAY. WIND GUSTS TO TROPICAL STORM FORCE COULD OCCUR IN SQUALLS OVER THE REMAINDER OF THE LEEWARD ISLANDS. RAINFALL...BERTHA IS EXPECTED TO PRODUCE RAINFALL AMOUNTS OF 1 TO 3 INCHES WITH ISOLATED AMOUNTS UP TO 6 INCHES ACROSS PORTIONS OF THE LEEWARD ISLANDS...AS WELL AS THE U. S. AND BRITISH VIRGIN ISLANDS. RAINFALL TOTALS OF 3 TO 6 INCHES WITH ISOLATED MAXIMUM TOTALS OF 10 INCHES ARE POSSIBLE ACROSS PUERTO RICO...WITH THE HEAVIEST TOTALS ACROSS THE SOUTHERN PORTION OF THE ISLAND. NEXT ADVISORY ------------- NEXT INTERMEDIATE ADVISORY...800 PM AST. NEXT COMPLETE ADVISORY...1100 PM AST. $$ FORECASTER BEVEN WWWW WTNT43 KNHC 012048 TROPICAL STORM BERTHA DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL032014 500 PM AST FRI AUG 01 2014 Earlier observations from an Air Force Reserve Hurricane Hunter aircraft and recent surface observations from Martinique indicate that Bertha still has a closed circulation, although the area of westerly winds south of the center is rather small. The aircraft- reported pressures were 1006-1007 mb, and the Martinique data suggests a current central pressure of 1007 mb. Based on this and the aircraft wind data, the initial intensity remains 45 kt. New convection is currently developing in this bands near the center, with a more solid area of convection farther east. The initial motion is now 290/21. Bertha continues to be steered west-northwestward by the flow around the Atlantic subtropical ridge and this should continue for the next 36-48 hours. After that time, the cyclone is expected to turn northward into a break in the ridge caused by a deep-layer trough over the eastern United States. This motion should be followed by recurvature into the westerlies over the Atlantic between Bermuda and New England, and then by a northeastward motion over the open North Atlantic. While the track guidance has nudged a little to the left since 6 hours ago, it remains in good agreement with this scenario. The new forecast track is therefore tweaked just a little to the left of the previous track, and it is a little faster than the previous track after recurvature. Bertha continues to experience about 15 kt of southwesterly vertical wind shear, and a combination of water vapor imagery and microwave total precipitable water shows abundant dry air near the storm. The forecast track calls for Bertha to interact with one or two upper- level troughs during the next 48 hours or so, which should cause some shear and dry air entrainment to continue. This, combined with the current lack of organization, suggests little change in strength should occur during that time. This part of the new intensity forecast is unchanged from the previous forecast. Subsequently, Bertha is expected to move into an environment of less shear and greater moisture. The intensity guidance responds to this by forecasting significant intensification, with several models showing Bertha becoming a hurricane during recurvature. Based on this, the latter part of the intensity forecast is nudged upward from the previous forecast, although it is still weaker than most of the guidance. An alternative scenario remains possible: that a combination of shear, dry air entrainment, and land interaction causes Bertha to degenerate to a tropical wave during the next 48 hours, followed by possible regeneration in the 72-120 hours when the system reaches the more favorable environment. FORECAST POSITIONS AND MAX WINDS INIT 01/2100Z 14.9N 61.2W 45 KT 50 MPH 12H 02/0600Z 16.0N 63.8W 45 KT 50 MPH 24H 02/1800Z 17.8N 66.9W 45 KT 50 MPH 36H 03/0600Z 19.9N 69.6W 45 KT 50 MPH 48H 03/1800Z 22.4N 72.0W 45 KT 50 MPH 72H 04/1800Z 27.5N 74.0W 50 KT 60 MPH 96H 05/1800Z 33.5N 71.0W 55 KT 65 MPH 120H 06/1800Z 38.5N 62.0W 60 KT 70 MPH $$ Forecaster Beven WWWW
Posted on: Fri, 01 Aug 2014 20:58:10 +0000