Home › discussion
 

Keywords :   


Tag: discussion

Tropical Storm GABRIELLE Forecast Discussion Number 11

2013-09-11 04:55:08| National Hurricane Center (Atlantic)

Issued at 1100 PM AST TUE SEP 10 2013 000 WTNT42 KNHC 110254 TCDAT2 TROPICAL STORM GABRIELLE DISCUSSION NUMBER 11 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072013 1100 PM AST TUE SEP 10 2013 SATELLITE IMAGERY SHOWS THAT THE PRIMARY AREA OF DEEP CONVECTION ASSOCIATED WITH GABRIELLE HAS BECOME DISPLACED WELL TO THE EAST OF THE LOW-LEVEL CENTER THIS EVENING...DUE TO STRONG SOUTHWESTERLY SHEAR. RADAR IMAGES FROM BERMUDA HAVE BEEN EXTREMELY HELPFUL IN TRACKING THE PROGRESS OF THE STORM THIS EVENING. THE RADAR DATA SHOW THAT GABRIELLE HAS DECELERATED AND THAT SOME SHALLOW CONVECTIVE BANDS ARE WRAPPING AROUND THE NORTHEASTERN PORTION OF THE CIRCULATION. THE INITIAL WIND SPEED REMAINS 50 KT...WHICH IS BASED ON THE EARLIER AIRCRAFT DATA AND RECENT OBSERVATIONS OF 35 TO 45 KT SUSTAINED WINDS AT WEATHER STATIONS ON BERMUDA. ANOTHER AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT WILL BE INVESTIGATING THE TROPICAL STORM OVERNIGHT. THE INITIAL MOTION ESTIMATE IS 355/7 KT. GABRIELLE SHOULD TURN NORTH-NORTHWESTWARD ON WEDNESDAY AS IT IS STEERED AROUND THE NORTHEASTERN SIDE OF A MID- TO UPPER-LEVEL LOW LOCATED EAST OF FLORIDA. IN A COUPLE OF DAYS...THE DEEP LAYER FLOW OFF THE EAST COAST OF THE UNITED STATES IS FORECAST TO TURN SOUTHWESTWARD AND STRENGTHEN AHEAD OF A MID-LATITUDE TROUGH. THIS SHOULD CAUSE GABRIELLE TO TURN NORTHEASTWARD AND BEGIN TO ACCELERATE. THE TRACK MODEL GUIDANCE IS IN GENERAL AGREEMENT ON THIS SCENARIO...BUT HAS SHIFTED A LITTLE WESTWARD DURING THE FIRST 36 HOURS. CONSEQUENTLY...THE NHC TRACK HAS BEEN NUDGED WESTWARD TO BE IN BETTER AGREEMENT WITH THE GUIDANCE. AFTER 36 HOURS...THE UPDATED NHC TRACK IS CLOSE TO THE PREVIOUS ADVISORY. GABRIELLE IS FORECAST TO REMAIN OVER WARM WATER BUT WITHIN MODERATE TO STRONG SOUTHWESTERLY SHEAR DURING THE NEXT FEW DAYS. THE SHEAR IS LIKELY TO PREVENT ANY SIGNIFICANT STRENGTHENING AND THE LATEST INTENSITY GUIDANCE NOW SHOWS LITTLE CHANGE IN STRENGTH DURING THE NEXT DAY OR SO. AS A RESULT...THE NHC INTENSITY FORECAST HAS BEEN ADJUSTED SLIGHTLY LOWER. IF ORGANIZED DEEP CONVECTION DOES NOT REDEVELOP IN ASSOCIATION WITH THE CYCLONE... GABRIELLE COULD DEGENERATE INTO A REMNANT LOW TOMORROW. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 32.0N 65.0W 50 KT 60 MPH 12H 11/1200Z 32.8N 65.3W 50 KT 60 MPH 24H 12/0000Z 33.6N 66.0W 45 KT 50 MPH 36H 12/1200Z 34.5N 66.6W 45 KT 50 MPH 48H 13/0000Z 36.3N 66.6W 45 KT 50 MPH 72H 14/0000Z 44.5N 61.5W 45 KT 50 MPH 96H 15/0000Z 54.0N 47.0W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 16/0000Z...DISSIPATED $$ FORECASTER BROWN

Tags: number discussion storm tropical

 

Tropical Storm HUMBERTO Forecast Discussion Number 10

2013-09-11 04:51:47| National Hurricane Center (Atlantic)

Issued at 1100 PM AST TUE SEP 10 2013 000 WTNT44 KNHC 110251 TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST TUE SEP 10 2013 AN EYE HAS BEEN SHOWING UP INTERMITTENTLY THIS EVENING IN HUMBERTO...BUT HAS NOT PERSISTED. MOREOVER...THE DEEP CONVECTION HAS BEEN SOMEWHAT ASYMMETRIC AND IS NOT MAINTAINING A CENTRAL DENSE OVERCAST CONTINUOUSLY. DVORAK CURRENT INTENSITY ESTIMATES FROM TAFB AND SAB HAVE REMAINED THE SAME OVER THE LAST SIX HOURS...AVERAGING AT 60 KT...WHILE ADT AND CIMSS AMSU SUGGEST A SUBSTANTIALLY WEAKER CYCLONE. IN DEFERENCE TO THE SUBJECTIVE DVORAK ANALYSES AND THE INTERMITTENT EYE...THE INITIAL INTENSITY REMAINS 60 KT. WHILE NO NEW ASCAT OBSERVATIONS WERE AVAILABLE...A 2240Z CIRA AMSU SIZE ANALYSIS SUGGESTED A SLIGHTLY LARGER RADIUS OF TROPICAL STORM FORCE WINDS...WHICH HAS BEEN SO ADJUSTED. HUMBERTO SHOULD STILL REACH HURRICANE INTENSITY...AS IT HAS ABOUT 24-36 HOURS TO GO WHILE TRAVERSING LUKEWARM WATER AND AN ENVIRONMENT OF LOW VERTICAL WIND SHEAR. BUT IN ABOUT 36-48 HOURS...THE VERTICAL SHEAR SHOULD INCREASE SUBSTANTIALLY DUE TO HUMBERTO APPROACHING CLOSER TO A LARGE UPPER-LEVEL TROUGH...WHILE AT THE SAME TIME THE SSTS SHOULD DROP TO A COOLISH 25-26C. GRADUAL...IF NOT RAPID...WEAKENING SHOULD OCCUR BETWEEN DAYS 2 AND 4. THE INTENSITY GUIDANCE IS RATHER TIGHTLY CLUSTERED AND THE NHC PREDICTION MIRRORS THIS AND IS JUST SLIGHTLY LOWER THAN THE PREVIOUS ADVISORY. HUMBERTO IS MOVING AT ABOUT 6 KT TOWARD 315 DEGREES...PRIMARILY DUE TO THE INFLUENCE OF A MID-LAYER RIDGE TO ITS NORTHEAST. WITH THE RIDGE WEAKENING...THE CYCLONE SHOULD TURN NORTHWARD IN ABOUT A DAY AND CONTINUE THIS MOTION FOR ANOTHER DAY OR SO. AROUND DAY 3...HUMBERTO SHOULD TURN AGAIN...THIS TIME TOWARD THE WEST...AS A STRONGER DEEP-LAYER RIDGE BUILDS IN NEAR THE AZORES. THE TRACK FORECAST IS BASED UPON A BLEND OF THE GFS...ECMWF...AND FIM GLOBAL MODELS...AND IS NEARLY IDENTICAL TO THE PREVIOUS ADVISORY THROUGH 48 HOURS AND THEN SLIGHTLY SOUTH THEREAFTER. FORECAST POSITIONS AND MAX WINDS INIT 11/0300Z 15.4N 28.4W 60 KT 70 MPH 12H 11/1200Z 16.4N 28.9W 65 KT 75 MPH 24H 12/0000Z 18.3N 29.1W 70 KT 80 MPH 36H 12/1200Z 20.2N 29.4W 75 KT 85 MPH 48H 13/0000Z 21.7N 29.9W 70 KT 80 MPH 72H 14/0000Z 23.5N 32.5W 60 KT 70 MPH 96H 15/0000Z 24.0N 37.5W 45 KT 50 MPH 120H 16/0000Z 24.5N 43.0W 40 KT 45 MPH $$ FORECASTER LANDSEA

Tags: number discussion storm tropical

 
 

Tropical Storm GABRIELLE Forecast Discussion Number 10

2013-09-10 22:56:37| National Hurricane Center (Atlantic)

Issued at 500 PM AST TUE SEP 10 2013 000 WTNT42 KNHC 102056 TCDAT2 TROPICAL STORM GABRIELLE DISCUSSION NUMBER 10 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072013 500 PM AST TUE SEP 10 2013 AN AIR FORCE RESERVE HURRICANE HUNTER AIRCRAFT INVESTIGATING GABRIELLE FOUND PEAK SFMR WINDS OF 45-50 KT NORTHWEST AND SOUTHEAST OF THE CENTER ON THEIR FIRST PASS THROUGH THE STORM...AND THE INITIAL INTENSITY IS INCREASED TO 50 KT FOR THIS ADVISORY. THE CENTRAL PRESSURE OF 1004 MB IS BASED ON A DROPSONDE FROM THE AIRCRAFT. GABRIELLE HAS BEEN ABLE TO STRENGTHEN TODAY DESPITE THE PRESENCE OF MODERATE SOUTHWESTERLY SHEAR WHICH HAS EXPOSED THE LOW-LEVEL CENTER TO THE SOUTHWEST OF THE DEEP CONVECTION. WHILE MODERATE SHEAR IS EXPECTED TO CONTINUE OR EVEN INCREASE OVER THE NEXT COUPLE OF DAYS...THE STATISTICAL/DYNAMICAL AND GLOBAL MODELS SHOW SOME STRENGTHENING DURING THAT TIME. THIS SEEMS TO BE SUPPORTED BY MARGINAL SSTS AND AN INCREASE IN UPPER-LEVEL DIVERGENCE AHEAD OF A MID/UPPER-LEVEL TROUGH. THE NHC FORECAST SHOWS THE POTENTIAL FOR SOME STRENGTHENING AND THEN LITTLE CHANGE THROUGH EXTRATROPICAL TRANSITION IN ABOUT 96 HOURS. THE INITIAL MOTION ESTIMATE IS 360/09. THE MODEL GUIDANCE SHOWS A TURN TOWARD THE NORTH-NORTHWEST WITH A DECREASE IN FORWARD SPEED OVER THE NEXT 12 TO 24 HOURS...AS GABRIELLE IS TUGGED WESTWARD BY A WEAKENING MID/UPPER-LEVEL LOW CURRENTLY SITUATED EAST OF FLORIDA. AT 48 HOURS AND BEYOND...AN ACCELERATION TOWARD THE NORTHEAST IS EXPECTED AHEAD OF A DEEP-LAYER TROUGH MOVING THROUGH EASTERN NORTH AMERICA. THE TRACK MODELS REMAIN IN REASONABLE AGREEMENT ON THE OVERALL SCENARIO...HOWEVER MUCH OF THE GUIDANCE HAS SHIFTED A LITTLE TO THE LEFT THIS CYCLE. OVERALL...THE NHC TRACK FORECAST IS SIMILAR TO THE PREVIOUS ONE THROUGH 48 HOURS AND AFTERWARD HAS BEEN ADJUSTED A BIT TO THE LEFT...BUT STILL LIES EAST OF THE MULTI-MODEL CONSENSUS. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 31.5N 64.9W 50 KT 60 MPH 12H 11/0600Z 32.6N 65.0W 55 KT 65 MPH 24H 11/1800Z 33.5N 65.5W 55 KT 65 MPH 36H 12/0600Z 34.3N 66.0W 55 KT 65 MPH 48H 12/1800Z 35.7N 66.5W 55 KT 65 MPH 72H 13/1800Z 42.0N 63.5W 55 KT 65 MPH 96H 14/1800Z 52.0N 52.4W 50 KT 60 MPH...POST-TROP/EXTRATROP 120H 15/1800Z...DISSIPATED $$ FORECASTER BRENNAN

Tags: number discussion storm tropical

 

Tropical Storm HUMBERTO Forecast Discussion Number 9

2013-09-10 22:32:11| National Hurricane Center (Atlantic)

Issued at 500 PM AST TUE SEP 10 2013 000 WTNT44 KNHC 102031 TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 PM AST TUE SEP 10 2013 ALTHOUGH CLOUD TOPS HAVE WARMED A BIT...THE CENTRAL DENSE OVERCAST HAS BEEN EXPANDING WITH A CONVECTIVE BAND WRAPPING AROUND THE SOUTHERN AND WESTERN SIDE OF THE CIRCULATION. DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB ARE T4.0/65 KT AND T3.5/55 KT... RESPECTIVELY...SO THE INITIAL WINDS ARE RAISED TO 60 KT. THE MAIN IMMEDIATE NEGATIVE FACTOR FOR FURTHER STRENGTHENING APPEARS TO BE DRIER AND MORE STABLE AIR LOCATED TO THE NORTH OF HUMBERTO THAT MAY BE GETTING INTO THE INNER CORE...BUT OTHERWISE LOW VERTICAL SHEAR AND WARM WATERS FAVOR AT LEAST SLOW INTENSIFICATION FOR ANOTHER 36 HOURS OR SO. AFTER THAT TIME...HUMBERTO WILL BE STRADDLING THE 26C SST ISOTHERM...BUT IT WILL ALSO BE MOVING INTO AN ENVIRONMENT OF 20-30 KT OF SOUTHWESTERLY SHEAR. WEAKENING IS THEREFORE ANTICIPATED AFTER DAY 2. THE INTENSITY MODELS CONTINUE TO CONVERGE ON A PEAK INTENSITY SOMEWHERE BETWEEN 70 AND 80 KT...WITH THE STATISTICAL GUIDANCE NOT NEARLY AS AGGRESSIVE AS IT WAS YESTERDAY. SUBSEQUENTLY...NO SIGNIFICANT CHANGES WERE REQUIRED TO THE OFFICIAL FORECAST. HUMBERTO HAS TURNED NORTHWESTWARD WITH AN INITIAL MOTION OF 310/7 KT. THE HIGH TO THE NORTH OF THE STORM IS NOW WEAKENING...AND THE EVOLVING PATTERN WILL ALLOW HUMBERTO TO TURN NORTHWARD BY 36 HOURS. THEN...JUST AS SHARPLY AS THE CYCLONE WILL BE TURNING NORTHWARD... IT WILL TURN SHARPLY WESTWARD BY DAY 5 WHEN A MID-LEVEL ANTICYCLONE REBUILDS NORTHWEST OF THE AZORES. THE TRACK GUIDANCE CONTINUES TO BE IN GOOD AGREEMENT...AND THE OFFICIAL FORECAST IS VERY CLOSE TO THE PREVIOUS FORECAST...THE MULTI-MODEL CONSENSUS TVCA...AND THE FLORIDA STATE SUPERENSEMBLE. FORECAST POSITIONS AND MAX WINDS INIT 10/2100Z 15.0N 28.1W 60 KT 70 MPH 12H 11/0600Z 15.9N 28.7W 65 KT 75 MPH 24H 11/1800Z 17.6N 29.1W 75 KT 85 MPH 36H 12/0600Z 19.6N 29.4W 80 KT 90 MPH 48H 12/1800Z 21.5N 29.8W 75 KT 85 MPH 72H 13/1800Z 24.0N 31.5W 65 KT 75 MPH 96H 14/1800Z 24.5N 36.0W 50 KT 60 MPH 120H 15/1800Z 24.5N 41.5W 45 KT 50 MPH $$ FORECASTER BERG

Tags: number discussion storm tropical

 

Tropical Storm GABRIELLE Forecast Discussion Number 9

2013-09-10 19:15:35| National Hurricane Center (Atlantic)

Issued at 130 PM AST TUE SEP 10 2013 000 WTNT42 KNHC 101715 TCDAT2 TROPICAL STORM GABRIELLE SPECIAL DISCUSSION NUMBER 9 NWS NATIONAL HURRICANE CENTER MIAMI FL AL072013 130 PM AST TUE SEP 10 2013 A PAIR OF ASCAT PASSES FROM 1342Z AND 1436Z INDICATE THAT GABRIELLE IS STRONGER THAN PREVIOUSLY ESTIMATED. BOTH PASSES SHOWED SEVERAL 45-KT WIND RETRIEVALS...AND THAT IS THE INITIAL INTENSITY FOR THIS SPECIAL ADVISORY. THE INTENSITY FORECAST HAS BEEN ADJUSTED UPWARD AT 12 AND 24 HOURS TO 50 KT BASED ON THE INCREASE IN THE INITIAL INTENSITY. THE ANALYZED 34-KT WIND RADII HAVE ALSO BEEN ADJUSTED OUTWARD BASED ON THE ASCAT DATA...AND THEIR FORECAST HAS BEEN MODIFIED AS WELL TO REFLECT THE LARGER WIND FIELD. AN AIR FORCE RESERVE AIRCRAFT WILL INVESTIGATE GABRIELLE LATER THIS AFTERNOON TO PROVIDE MORE DETAILED INFORMATION ON THE STRENGTH AND STRUCTURE OF THE CYCLONE. NO CHANGES WERE MADE TO THE PREVIOUS TRACK FORECAST FOR THIS SPECIAL ADVISORY. NOTE THAT THIS SPECIAL ADVISORY TAKES THE PLACE OF THE 200 PM AST/1800 UTC INTERMEDIATE ADVISORY. FORECAST POSITIONS AND MAX WINDS INIT 10/1730Z 30.9N 64.8W 45 KT 50 MPH 12H 11/0000Z 31.9N 64.9W 50 KT 60 MPH 24H 11/1200Z 33.1N 65.2W 50 KT 60 MPH 36H 12/0000Z 34.0N 65.8W 45 KT 50 MPH 48H 12/1200Z 35.2N 66.2W 45 KT 50 MPH 72H 13/1200Z 39.5N 65.0W 45 KT 50 MPH 96H 14/1200Z 49.0N 56.5W 45 KT 50 MPH...POST-TROP/EXTRATROP 120H 15/1200Z...DISSIPATED $$ FORECASTER BRENNAN

Tags: number discussion storm tropical

 

Sites : [1213] [1214] [1215] [1216] [1217] [1218] [1219] [1220] [1221] [1222] [1223] [1224] [1225] [1226] [1227] [1228] [1229] [1230] [1231] [1232] next »