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| #531866 (Received by flhurricane at: 10:53 PM 04.Aug.2012) TCDAT1 TROPICAL STORM FLORENCE DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012 1100 PM AST SAT AUG 04 2012 FLORENCE IS BECOMING BETTER ORGANIZED. BANDING FEATURES ASSOCIATED WITH THE CYCLONE HAVE RECENTLY DISSIPATED IN FAVOR OF A CENTRAL DENSE OVERCAST. EARLIER TRMM AND WINDSAT OVERPASSES REVEAL A WELL- DEFINED LOW-LEVEL STRUCTURE UNDERNEATH THIS NEW CONVECTIVE MASS... WITH A NEARLY CLOSED RING OF CONVECTION NOW PRESENT. A DVORAK INTENSITY ESTIMATE OF 3.5/55 KT FROM TAFB AT 0000 UTC AND THREE- HOURLY AVERAGED ADT VALUES OF AROUND 3.3 ARE THE BASIS FOR INCREASING THE INITIAL INTENSITY TO 50 KT FOR THIS ADVISORY. THE INTENSITY FORECAST IS TRICKY. DESPITE BEING IN A LOW-SHEAR ENVIRONMENT...FLORENCE IS FORECAST TO MOVE THROUGH A TONGUE OF MARGINALLY WARM WATERS OVER THE NEXT COUPLE OF DAYS. IN ADDITION... EUMETSAT RGB SATELLITE IMAGERY INDICATES THAT THE CYCLONE IS SURROUNDED BY A RATHER DRY AIR MASS...AND THIS AIR MASS SHOULD ACCOMPANY FLORENCE ON ITS WESTWARD TREK. THESE NEGATIVE FACTORS SUGGEST THAT ANY STRENGTHENING IN THE SHORT TERM WOULD NOT LIKELY BE SIGNIFICANT. BEYOND 72 HOURS...GLOBAL MODELS SHOW FLORENCE ENCOUNTERING INCREASING SOUTHWESTERLY SHEAR ASSOCIATED WITH AN UPPER-LEVEL TROUGH OVER THE CENTRAL ATLANTIC. EVEN THOUGH THE STORM WILL BE MOVING OVER WARMER WATERS BY THIS TIME...THE SHEAR SHOULD BE STRONG ENOUGH TO INDUCE WEAKENING. THE NEW NHC INTENSITY FORECAST IS ADJUSTED UPWARD THROUGH 48 HOURS BASED ON CURRENT TRENDS AND IS ABOUT THE SAME AS THE PREVIOUS FORECAST AFTER THAT TIME. THE FORECAST IS IN EXCELLENT AGREEMENT WITH THE LATEST SHIPS/LGEM OUTPUT. THE INITIAL MOTION ESTIMATE IS 295/13. A MID-LEVEL RIDGE OVER THE EASTERN ATLANTIC IS EXPECTED TO BUILD WESTWARD DURING THE NEXT SEVERAL DAYS...WHICH WILL CAUSE THE TRACK OF FLORENCE TO BEND TOWARD THE WEST. LATE IN THE FORECAST PERIOD...THE CYCLONE IS EXPECTED TO ENCOUNTER A WEAKNESS IN THE SUBTROPICAL RIDGE OVER THE CENTRAL ATLANTIC WHICH SHOULD INDUCE A WEST-NORTHWESTERLY HEADING. ALTHOUGH THE SPREAD IN THE TRACK GUIDANCE HAS DECREASED THIS CYCLE...IT REMAINS FAIRLY SIGNIFICANT BEYOND 72 HOURS. THE DIFFERENCE IN TRACK SOLUTIONS AT LATER TIMES APPEARS DEPENDENT ON THE VERTICAL DEPTH/ STRENGTH OF THE CYCLONE...WITH THE ECMWF/GFDL/HWRF FORECASTING A WEAKER VERSION OF FLORENCE AND THE GFS FAVORING A STRONGER SYSTEM. THE NEW NHC FORECAST TRACK REMAINS IN BETWEEN THESE TWO EXTREMES BUT HAS BEEN ADJUSTED TOWARD THE CAMP OF MODELS FAVORING A WEAKER CYCLONE GIVEN THE SHEAR FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 16.1N 33.0W 50 KT 60 MPH 12H 05/1200Z 16.5N 34.8W 55 KT 65 MPH 24H 06/0000Z 17.0N 37.2W 60 KT 70 MPH 36H 06/1200Z 17.5N 39.7W 60 KT 70 MPH 48H 07/0000Z 18.1N 42.6W 60 KT 70 MPH 72H 08/0000Z 19.3N 49.0W 45 KT 50 MPH 96H 09/0000Z 20.9N 55.1W 35 KT 40 MPH 120H 10/0000Z 23.5N 60.5W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ FORECASTER KIMBERLAIN |
| #531862 (Received by flhurricane at: 10:50 PM 04.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 14 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 1100 PM EDT SAT AUG 04 2012 DESPITE AN IMPRESSIVE APPEARANCE IN INFRARED IMAGERY...MICROWAVE IMAGERY AND REPORTS FROM AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INDICATE THAT ERNESTO HAS LOST SOME ORGANIZATION DURING THE PAST SEVERAL HOURS. THE MICROWAVE DATA SUGGESTS THAT THE LOW-LEVEL CENTER HAS BECOME PARTLY EXPOSED TO THE NORTHWEST OF THE STRONG CONVECTION...AND THE AIRCRAFT REPORTS THAT THE CENTRAL PRESSURE HAS RISEN TO 1007 MB. SINCE THE PLANE HAS NOT YET FULLY SAMPLED THE NORTHEASTERN QUADRANT WHERE THE STRONGEST WINDS WERE FOUND EARLIER...THE INITIAL INTENSITY IS HELD AT 50 KT. HOWEVER... IT IS POSSIBLE THAT THIS ESTIMATE IS GENEROUS. THE LOW-LEVEL CENTER HAS ACCELERATED WEST-NORTHWESTWARD SINCE THE LAST ADVISORY...WITH A SHORT-TERM FORWARD SPEED OF OVER 20 KT. A LONGER-TERM MOTION IS 285/19...WHICH IS THE INITIAL MOTION FOR THE ADVISORY. THE REASON FOR THIS TRACK CHANGE IS UNCLEAR. HOWEVER... THE GUIDANCE IS IN GOOD AGREEMENT THAT ERNESTO SHOULD RESUME A WESTWARD MOTION DURING THE NEXT 12 HR OR SO ON THE SOUTH SIDE OF THE SUBTROPICAL RIDGE. AFTER 24-36 HR...THE RIDGE SHOULD GRADUALLY WEAKEN AS A MID/UPPER-LEVEL TROUGH DEVELOPS OVER THE EASTERN UNITED STATES. WHILE SOME SPREAD REMAINS...THE GUIDANCE HAS COME INTO BETTER AGREEMENT THAT ERNESTO WILL TURN WEST-NORTHWESTWARD AT A REDUCED FORWARD SPEED AFTER 36 HR...MOVING OVER THE YUCATAN PENINSULA OF MEXICO BETWEEN 72-96 HR AND REACHING THE SOUTHERN OR SOUTHWESTERN GULF OF MEXICO BY THE END OF THE FORECAST PERIOD. THE NEW FORECAST TRACK IS SHIFTED A LITTLE NORTH OF THE PREVIOUS TRACK THROUGH 24 HR DUE TO THE INITIAL MOTION. HOWEVER...IT HAS BEEN SHIFTED SOUTHWARD AFTER THAT TIME TO LIE NEAR THE VARIOUS CONSENSUS MODELS. OVERALL...THE NEW FORECAST TRACK IS FASTER THAN THE PREVIOUS TRACK. IT IS ALSO UNCLEAR WHY ERNESTO HAS LOST ORGANIZATION SINCE THE OUTFLOW IS GOOD IN ALL DIRECTIONS...THE VERTICAL WIND SHEAR IS LIGHT...AND THE SEA SURFACE TEMPERATURES ARE WARM. ONE POSSIBLE CAUSE MIGHT BE DRY AIR SEEN IN WATER VAPOR IMAGERY WEST OF THE CYCLONE. THE DYNAMICAL GUIDANCE CONTINUES TO SUGGEST THAT ERNESTO WILL NOT STRENGTHEN MUCH BEFORE REACHING THE NORTHWESTERN CARIBBEAN...WHILE THE STATISTICAL-DYNAMICAL MODELS CONTINUE TO FORECAST STEADY STRENGTHENING THROUGH THE FORECAST PERIOD. GIVEN THE TRENDS DURING THE PAST 24 HR...THE NEW INTENSITY FORECAST CALLS FOR A LOWER INTENSIFICATION RATE THAN THE PREVIOUS ADVISORY...WITH ERNESTO BECOMING A HURRICANE IN 48 HR. GIVE THE DIVERGENT GUIDANCE...THE INTENSITY FORECAST REMAINS OF LOW CONFIDENCE. FORECAST POSITIONS AND MAX WINDS INIT 05/0300Z 15.4N 72.7W 50 KT 60 MPH 12H 05/1200Z 15.8N 75.5W 50 KT 60 MPH 24H 06/0000Z 16.1N 78.7W 50 KT 60 MPH 36H 06/1200Z 16.3N 81.0W 60 KT 70 MPH 48H 07/0000Z 17.0N 82.9W 65 KT 75 MPH 72H 08/0000Z 18.5N 86.5W 75 KT 85 MPH 96H 09/0000Z 20.5N 89.5W 70 KT 80 MPH...INLAND 120H 10/0000Z 22.0N 92.5W 65 KT 75 MPH...OVER WATER $$ FORECASTER BEVEN |
| #531813 (Received by flhurricane at: 4:35 PM 04.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 13 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 500 PM EDT SAT AUG 04 2012 A RECONNAISSANCE PLANE EARLIER THIS MORNING FOUND A WEAKER CYCLONE...BUT DURING THE LAST PASS THROUGH THE CENTER AROUND NOON...THE PLANE REPORTED THAT THE CENTRAL PRESSURE HAD DROPPED TO 1004 MB FROM 1008 MB...AND FOUND A BETTER DEFINED CIRCULATION CENTER. SINCE THAT TIME...THE SATELLITE PRESENTATION HAS CONTINUED TO INCREASE IN ORGANIZATION. THE CENTER IS EMBEDDED WITHIN A CIRCULAR AREA OF DEEP CONVECTION...AND THE OUTFLOW IS WELL ESTABLISHED WHICH IS NOT COMMON FOR A CYCLONE IN THE CENTRAL CARIBBEAN. T-NUMBERS WERE 3.5 AND 3.0 AT 1800 UTC...AND OBJECTIVE NUMBERS HAVE REACHED 4.3 ON THE DVORAK SCALE DURING THE PAST HOUR. ON THIS BASIS...THE INTENSITY HAS BEEN CONSERVATIVELY BEEN ADJUSTED UPWARD TO 50 KNOTS. HOWEVER... GIVEN THE SATELLITE PRESENTATION... THE NEXT RECONNAISSANCE PLANE COULD FIND STRONGER WINDS. AS INDICATED IN THE PREVIOUS ADVISORY...I DO NOT HAVE ANY REASONS TO FORECAST WEAKENING AS SOME OF THE DYNAMICAL MODELS PREDICT... INCLUDING THE HWRF AND THE GFDL. THE SHEAR IS LOW AHEAD OF THE CYCLONE AND ERNESTO WILL MOVE OVER AN OCEAN WITH HIGHER HEAT CONTENT. GIVEN SUCH CONDITIONS...THE OFFICIAL FORECAST CALLS FOR ERNESTO TO BECOME A HURRICANE IN THE WESTERN CARIBBEAN AS SUGGESTED BY THE SHIPS AND LGEM MODELS. ERNESTO CONTINUES TO MOVE TOWARD THE WEST OR 280 DEGREES AT 16 KNOTS...EMBEDDED IN THE FLOW SOUTH OF THE SUBTROPICAL RIDGE. THIS GENERAL TRACK IS EXPECTED TO CONTINUE FOR THE NEXT 24 TO 48 HOURS. AFTER THAT...THE SUBTROPICAL HIGH IS FORECAST TO WEAKEN...RESULTING IN ERNESTO TURNING MORE TOWARD THE WEST-NORTHWEST WITH A DECREASE IN FORWARD SPEED. THE OFFICIAL FORECAST IS VERY CLOSE TO THE SOLUTION OF MOST THE GLOBAL MODELS...BRINGING ERNESTO OVER THE NORTHWESTERN CARIBBEAN AND ACROSS THE YUCATAN PENINSULA. AT THIS TIME...THE NHC FORECAST DISREGARDS THE NORTHWARD TURN INDICATED BY THE GFDL/HWRF MODEL PAIR. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 14.8N 70.1W 50 KT 60 MPH 12H 05/0600Z 15.2N 72.6W 50 KT 60 MPH 24H 05/1800Z 15.7N 76.0W 55 KT 65 MPH 36H 06/0600Z 16.0N 79.0W 65 KT 75 MPH 48H 06/1800Z 16.5N 81.5W 70 KT 80 MPH 72H 07/1800Z 18.0N 84.5W 75 KT 85 MPH 96H 08/1800Z 19.5N 87.0W 80 KT 90 MPH 120H 09/1800Z 21.5N 90.5W 60 KT 70 MPH $$ FORECASTER AVILA |
| #531812 (Received by flhurricane at: 4:35 PM 04.Aug.2012) TCDAT1 TROPICAL STORM FLORENCE DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012 500 PM AST SAT AUG 04 2012 AFTER LOOKING A LITTLE RAGGED EARLIER...CONVECTION HAS REDEVELOPED NEAR THE CENTER OF FLORENCE...WHICH APPEARS TO BE THE START OF A CENTRAL DENSE OVERCASE PATTERN. SUBJECTIVE SATELLITE INTENSITY ESTIMATES WERE 35 KT AND 45 KT FROM SAB AND TAFB RESPECTIVELY. SINCE A TRMM MICROWAVE PASS FROM EARLIER TODAY SUGGESTED THAT SOME PRIMITIVE INNER CORE FEATURES HAD FORMED...AND BOTH AMSU AND ADT DATA INDICATE A STRONGER CYCLONE...THE INITIAL INTENSITY WILL BE BUMPED UP TO 45 KT. THE CURRENT SYMMETRIC OUTFLOW PATTERN WITH FLORENCE APPEARS FAVORABLE FOR FURTHER INTENSIFICATION. HOWEVER...THE SYSTEM IS PASSING OVER WATERS COOLER THAN 26.5C...AND IS APPROACHING A MORE STABLE AND DRY ENVIRONMENT AS INDICATED BY EUMETSAT RGB AIRMASS IMAGERY. THE INTENSITY GUIDANCE HAS A WIDE RANGE OF POSSIBILITIES. THE STATISTICAL-BASED TOOLS FORECAST FLORENCE TO BE NEAR OR ABOVE HURRICANE STRENGTH IN A DAY OR TWO...WHICH IS CONTRASTED WITH THE WEAKENING FORECAST BY THE HWRF/GFDL MODELS. THE OFFICIAL FORECAST IS JUST A BIT ABOVE THE INTENSITY CONSENSUS AND IS HIGHER THAN THE PREVIOUS ONE. GIVEN THE EARLIER MICROWAVE STRUCTURE...IT IS TEMPTING TO RAISE THE WIND PREDICTION MORE THAN WHAT IS INDICATED BELOW...BUT I HAVE ELECTED TO REMAIN CONSERVATIVE ON THIS FORECAST CONSIDERING THE MARGINAL ENVIRONMENT. THE INITIAL MOTION ESTIMATE IS A LITTLE SLOWER...295/13. A BUILDING MID-TROPOSPHERIC HIGH OVER THE EASTERN ATLANTIC OCEAN IS EXPECTED TO CAUSE FLORENCE TO BEND TO A WESTWARD HEADING DURING THE NEXT DAY OR TWO. HOWEVER...THE GLOBAL MODELS HAVE A WIDER SPREAD THAN EARLIER TODAY...WITH THE ECMWF AND GFS SHOWING LITTLE RUN-TO-RUN CONSISTENCY. GENERALLY THE MODELS THAT ARE FORECASTING A MORE POWERFUL SYSTEM...SUCH AS THE GFS...ARE CAUSING FLORENCE TO TURN NORTHWESTWARD AROUND DAY 4 IN RESPONSE TO A WEAKNESS IN THE RIDGE. A WEAKER CYCLONE...AS INDICATED BY THE ECMWF...WOULD PROBABLY JUST CONTINUE MOVING WESTWARD. SINCE THE LATEST INTENSITY FORECAST IS BETWEEN THESE TWO EXTREMES...THE LATEST NHC FORECAST IS CLOSE TO THE MODEL CONSENSUS...JUST A BIT NORTH OF THE PREVIOUS FORECAST IN THE LONG RANGE PERIOD. FORECAST POSITIONS AND MAX WINDS INIT 04/2100Z 15.3N 31.7W 45 KT 50 MPH 12H 05/0600Z 15.8N 33.4W 50 KT 60 MPH 24H 05/1800Z 16.2N 35.7W 50 KT 60 MPH 36H 06/0600Z 16.6N 38.1W 45 KT 50 MPH 48H 06/1800Z 17.1N 41.2W 45 KT 50 MPH 72H 07/1800Z 18.5N 47.8W 40 KT 45 MPH 96H 08/1800Z 20.5N 54.0W 35 KT 40 MPH 120H 09/1800Z 23.0N 59.0W 30 KT 35 MPH...POST-TROP/REMNT LOW $$ FORECASTER BLAKE |
| #531743 (Received by flhurricane at: 10:50 AM 04.Aug.2012) TCDAT1 TROPICAL STORM FLORENCE DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012 1100 AM AST SAT AUG 04 2012 SATELLITE IMAGES INDICATE THAT THE CLOUD PATTERN OF THE CYCLONE HAS BECOME BETTER ORGANIZED DURING THE PAST SEVERAL HOURS. ALTHOUGH THE CENTRAL CONVECTION HAS RECENTLY WEAKENED...A WELL-DEFINED BAND STILL WRAPS AROUND THE EAST AND SOUTH SIDES OF THE CENTER. A BLEND OF THE SATELLITE CLASSIFICATIONS FROM TAFB AND SAB GIVES AN INITIAL INTENSITY OF 40 KT. NO SIGNIFICANT CHANGES IN INTENSITY ARE FORECAST FOR THE NEXT COUPLE OF DAYS AS FLORENCE MOVES OVER MARGINAL SSTS AND MODERATE SHEAR. AFTER THAT TIME...THE CYCLONE SHOULD WEAKEN MORE STEADILY DUE TO AN INCREASE IN SOUTHWESTERLY SHEAR FROM A LARGE UPPER-LEVEL TROUGH. THE OFFICIAL FORECAST IS CLOSE TO THE INTENSITY CONSENSUS THROUGH TWO DAYS...AND THEN FOLLOWS THE WEAKENING TREND OF THE GLOBAL AND REGIONAL HURRICANE MODELS. THE INITIAL MOTION ESTIMATE IS UNCHANGED AT 295/14. A MID- TROPOSPHERIC HIGH OVER THE EASTERN ATLANTIC OCEAN IS EXPECTED TO STEER FLORENCE ON A WEST-NORTHWESTWARD TO WESTWARD PATH DURING THE NEXT SEVERAL DAYS. THE BULK OF THE GUIDANCE IS IN GOOD AGREEMENT ON THIS SCENARIO...AND LITTLE CHANGE WAS MADE TO THE FORECAST FOR THE FIRST 3 DAYS. AT LONG RANGE...THE TRACK MODELS CONTINUE TO SHIFT TO THE NORTH...AND THE OFFICIAL FORECAST FOLLOWS SUIT. THE FORMATION OF FLORENCE THIS MORNING MARKS THE THIRD EARLIEST OCCASION THAT THE SIXTH NAMED STORM HAS OCCURRED IN THE ATLANTIC BASIN...BEHIND ONLY 1936 AND 2005. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 14.8N 30.6W 40 KT 45 MPH 12H 05/0000Z 15.5N 32.2W 45 KT 50 MPH 24H 05/1200Z 16.0N 34.5W 45 KT 50 MPH 36H 06/0000Z 16.3N 36.9W 45 KT 50 MPH 48H 06/1200Z 16.5N 39.5W 40 KT 45 MPH 72H 07/1200Z 17.5N 46.0W 35 KT 40 MPH 96H 08/1200Z 19.5N 53.0W 30 KT 35 MPH...POST-TROP/REMNT LOW 120H 09/1200Z 22.0N 59.5W 25 KT 30 MPH...POST-TROP/REMNT LOW $$ FORECASTER BLAKE |
| #531741 (Received by flhurricane at: 10:47 AM 04.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 12 NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 1100 AM AST SAT AUG 04 2012 DESPITE THE EXCELLENT PRESENTATION ON SATELLITE WITH CYCLONICALLY CURVED CONVECTIVE BANDS AND A WELL ESTABLISHED UPPER-LEVEL OUTFLOW...DATA FROM A RECONNAISSANCE PLANE INDICATE THAT ERNESTO HAS NOT BECOME ANY BETTER ORGANIZED. IN FACT...THE WINDS HAVE DECREASED TO 45 KT AND THE PRESSURE HAS RISEN TO 1008 MB. I DO NOT HAVE ANY REASONS FOR THE CURRENT WEAKENING BUT I HAVE NO REASON TO FORECAST ADDITIONAL WEAKENING EITHER. THE SHEAR IS ANTICIPATED TO REMAIN LOW ACROSS THE CARIBBEAN...AND ERNESTO WILL MOVE OVER AN OCEAN WITH HIGHER HEAT CONTENT. GIVEN SUCH CONDITIONS...THE OFFICIAL FORECAST CALLS FOR ERNESTO TO BECOME A HURRICANE IN THE WESTERN CARIBBEAN. THIS FORECAST IS UNCERTAIN SINCE MODELS ARE IN DISAGREEMENT. SHIPS...LGEM AND THE GFDL FORECAST ERNESTO TO BECOME A HURRICANE WHILE THE HWRF EITHER FORECASTS NO CHANGE OR WEAKENING. ERNESTO IS MOVING TOWARD THE WEST-NORTHWEST OR 285 DEGREES AT 16 KNOTS EMBEDDEED IN THE FLOW SOUTH OF THE SUBTROPICAL RIDGE. THIS TRACK IS EXPECTED TO CONTINUE FOR THE NEXT 24 TO 48 HOURS. AFTER THAT...THERE WILL PROBABLY BE A WEAKENING OF THE RIDGE AND ERNESTO COULD TURN A LITTLE MORE TO THE NORTHWEST TOWARD THE YUCATAN PENINSULA AND THE BAY OF CAMPECHE. MODELS ARE IN GOOD AGREEMENT WITH THIS SCENARIO DURING THE NEXT TWO DAYS...BUT BEYOND THAT TIME...THERE ARE LARGE DIFFERENCES. BOTH THE GFDL AND HWRF TURN ERNESTO NORTHWARD...AND THE RELIABLE GLOBAL MODELS KEEP THE CYCLONE ON A WEST-NORTHWEST TRACK. THE OFFICIAL FORECAST IS HEAVILY BIASED TOWARD THE GLOBAL MODELS AND IS VERY SIMILAR TO THE PREVIOUS NHC FORECAST. FORECAST POSITIONS AND MAX WINDS INIT 04/1500Z 14.4N 68.7W 45 KT 50 MPH 12H 05/0000Z 14.8N 71.2W 45 KT 50 MPH 24H 05/1200Z 15.5N 74.5W 50 KT 60 MPH 36H 06/0000Z 15.7N 77.5W 65 KT 75 MPH 48H 06/1200Z 16.5N 80.5W 70 KT 80 MPH 72H 07/1200Z 18.0N 84.0W 80 KT 90 MPH 96H 08/1200Z 19.5N 87.0W 70 KT 80 MPH 120H 09/1200Z 22.0N 90.5W 60 KT 70 MPH $$ FORECASTER AVILA |
| #531690 (Received by flhurricane at: 4:56 AM 04.Aug.2012) TCDAT5 TROPICAL STORM ERNESTO DISCUSSION NUMBER 11...CORRECTED NWS NATIONAL HURRICANE CENTER MIAMI FL AL052012 500 AM AST SAT AUG 04 2012 CORRECTED TIME OF AMSU PASS IN FIRST PARAGRAPH THE SATELLITE PRESENTATION OF ERNESTO HAS BEEN GRADUALLY IMPROVING OVERNIGHT. THE COVERAGE OF COLD TOPS HAS INCREASED WHILE CONVECTIVE BANDING FEATURES HAVE BECOME MORE APPARENT AND THE OUTFLOW HAS EXPANDED IN THE NORTHERN SEMICIRCLE. IN ADDITION...AN AMSU PASS FROM 0549 UTC SHOWED A LITTLE BETTER STRUCTURE IN THE INNER CORE. THE INITIAL INTENSITY IS RAISED TO 50 KT BASED ON A BLEND OF THE LATEST DVORAK ESTIMATES FROM TAFB AND SAB. THE LOW-SHEAR ENVIRONMENT AND IMPROVED STRUCTURE OF THE CYCLONE SUGGEST AT LEAST STEADY INTENSIFICATION OVER THE NEXT COUPLE OF DAYS. HOWEVER...THE DISAGREEMENT IN THE INTENSITY GUIDANCE CONTINUES. THE SHIPS AND LGEM STILL SHOW A FASTER PACE OF INTENSIFICATION...WHILE THE DYNAMICAL MODELS SHOW STRENGTHENING AT A MUCH SLOWER RATE. GIVEN THE CURRENT TRENDS...THE OFFICIAL FORECAST HAS BEEN ADJUSTED UPWARD AND SHOWS ERNESTO BECOMING A HURRICANE IN 36 HOURS...BUT REMAINS BELOW THE STATISTICAL-DYNAMICAL GUIDANCE. LATER IN THE PERIOD...THE GFDL SHOWS MORE INTENSIFICATION THAN EARLIER RUNS...BUT THE HWRF AND MUCH OF THE HFIP GUIDANCE REMAIN WEAKER. AT DAYS 3 THROUGH 5 THE NEW NHC FORECAST HAS BEEN ADJUSTED UPWARD SLIGHTLY...AND IS CLOSE TO THE IV15 CONSENSUS AND THE FLORIDA STATE SUPERENSEMBLE. NEEDLESS TO SAY...THERE IS LOW CONFIDENCE IN THE INTENSITY FORECAST THROUGH THE PERIOD. THE INITIAL MOTION ESTIMATE IS 275/16 AS ERNESTO IS SITUATED SOUTH OF THE SUBTROPICAL RIDGE. THE TRACK MODEL GUIDANCE IS IN GOOD AGREEMENT THROUGH 48 HOURS IN SHOWING A CONTINUED WESTWARD MOTION AS THE RIDGE BUILDS WESTWARD TO NORTH OF THE CYCLONE. THROUGH THIS TIME THE NHC FORECAST IS SIMPLY AN UPDATE OF THE PREVIOUS ONE. AT DAYS 3 THROUGH 5 THERE CONTINUES TO BE LARGE SPREAD IN THE MODEL GUIDANCE. THE BIGGEST CHANGE THIS CYCLE IS A SOUTHWARD SHIFT IN THE UKMET...WHICH NOW JOINS THE GFS AND ECMWF IN SHOWING THAT ERNESTO WILL REMAIN TOO FAR SOUTH TO MOVE INTO A WEAKNESS IN THE SUBTROPICAL RIDGE THAT DEVELOPS OVER THE EASTERN GULF OF MEXICO IN 4 TO 5 DAYS. HOWEVER...THE GFDL...HWRF...AND SEVERAL OF THE HFIP MODELS CONTINUE TO SHOW ERNESTO GAINING MORE LATITUDE IN THE SECOND HALF OF THE FORECAST PERIOD. THE NHC FORECAST HAS BEEN ADJUSTED A LITTLE TO THE SOUTH TOWARD THE NEW MULTI-MODEL CONSENSUS AT DAYS 3 THROUGH 5...BUT STILL LIES TO THE RIGHT OF THE CENTER OF THE GUIDANCE ENVELOPE. INTERESTS IN JAMAICA SHOULD MONITOR THE PROGRESS OF ERNESTO...AS A TROPICAL STORM WATCH OR WARNING COULD BE REQUIRED FOR PORTIONS OF THAT ISLAND LATER TODAY. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 14.1N 67.2W 50 KT 60 MPH 12H 04/1800Z 14.5N 69.7W 55 KT 65 MPH 24H 05/0600Z 15.1N 73.1W 60 KT 70 MPH 36H 05/1800Z 15.7N 76.4W 65 KT 75 MPH 48H 06/0600Z 16.3N 79.1W 70 KT 80 MPH 72H 07/0600Z 17.5N 83.0W 75 KT 85 MPH 96H 08/0600Z 19.5N 86.5W 80 KT 90 MPH 120H 09/0600Z 21.5N 90.0W 70 KT 80 MPH $$ FORECASTER BRENNAN |
| #531687 (Received by flhurricane at: 4:56 AM 04.Aug.2012) TCDAT1 TROPICAL DEPRESSION SIX DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL062012 500 AM AST SAT AUG 04 2012 THERE HAS BEEN LITTLE CHANGE IN THE STRUCTURE OF THE DEPRESSION OVERNIGHT. THE CYCLONE CONTINUES TO PRODUCE A FAIRLY CIRCULAR AREA OF DEEP CONVECTION...WITH THE LOW-LEVEL CENTER ESTIMATED TO BE NEAR THE NORTHERN EDGE OF THE CONVECTIVE MASS. SATELLITE INTENSITY ESTIMATES WERE A UNANIMOUS 30 KT FROM TAFB...SAB...AND UW-CIMSS AT 0600 UTC...THEREFORE...THE INITIAL WIND SPEED IS HELD AT THAT VALUE. THE FACTORS THAT COULD AFFECT THE FUTURE INTENSITY OF THE DEPRESSION ARE MIXED. THE CURRENT MODERATE NORTHEASTERLY SHEAR IS EXPECTED TO DECREASE DURING THE NEXT COUPLE OF DAYS...WHICH IS CONDUCIVE FOR STRENGTHENING. ON THE OTHER HAND...DRY AIR IN THE VICINITY OF THE CYCLONE AND MARGINALLY WARM WATER TEMPERATURES COULD INHIBIT DEVELOPMENT. THE GUIDANCE SHOWS A LARGE SPLIT...WITH THE SHIPS AND LGEM MODELS SHOWING SLOW BUT STEADY INTENSIFICATION DURING THE NEXT 5 DAYS. THE DYNAMICAL MODELS...HOWEVER...PREDICT LITTLE OR NO STRENGTHENING. IN FACT...MOST OF THE GLOBAL MODELS SHOW THE SYSTEM OPENING INTO A TROUGH IN 3 TO 4 DAYS. THE OFFICIAL FORECAST SHOWS MODEST STRENGTHENING FOR THE NEXT DAY OR TWO...FOLLOWING THE INTENSITY MODEL CONSENSUS. THEREAFTER...THE NHC FORECAST CONTINUES TO LEAN TOWARD THE DYNAMICAL MODELS IN PREDICTING A GRADUAL WEAKENING TREND. THE INITIAL MOTION ESTIMATE IS ABOUT THE SAME AS BEFORE...295/14. A GENERAL WESTWARD TO WEST-NORTHWESTWARD MOTION IS ANTICIPATED FOR THE NEXT SEVERAL DAYS AS A LOW- TO MID-LEVEL HIGH BUILDS WESTWARD TO THE NORTH OF THE TROPICAL CYCLONE. THE NEW OFFICIAL FORECAST HAS BEEN ADJUSTED A LITTLE FASTER AND TO THE NORTH OF THE PREVIOUS ONE AT DAYS 4 AND 5 TO COME INTO BETTER AGREEMENT WITH THE LATEST MODEL GUIDANCE. FORECAST POSITIONS AND MAX WINDS INIT 04/0900Z 14.2N 29.1W 30 KT 35 MPH 12H 04/1800Z 14.9N 30.8W 35 KT 40 MPH 24H 05/0600Z 15.5N 32.9W 40 KT 45 MPH 36H 05/1800Z 16.0N 35.1W 40 KT 45 MPH 48H 06/0600Z 16.2N 37.5W 35 KT 40 MPH 72H 07/0600Z 16.7N 43.3W 30 KT 35 MPH 96H 08/0600Z 17.5N 50.0W 25 KT 30 MPH...POST-TROP/REMNT LOW 120H 09/0600Z 19.0N 56.5W 20 KT 25 MPH...POST-TROP/REMNT LOW $$ FORECASTER CANGIALOSI |
