Home › discussion
 

Keywords :   


Tag: discussion

Tropical Storm HUMBERTO Forecast Discussion Number 5

2013-09-09 22:40:30| National Hurricane Center (Atlantic)

Issued at 500 PM AST MON SEP 09 2013 000 WTNT44 KNHC 092040 TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 5 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 PM AST MON SEP 09 2013 SATELLITE IMAGERY INDICATES THAT DEEP CONVECTION ASSOCIATED WITH HUMBERTO IS SHOWING MORE PRONOUNCED BANDING...AND THE LOW-LEVEL CENTER IS BECOMING MORE EMBEDDED BENEATH THE COLD CLOUD TOPS. SUBJECTIVE DVORAK ESTIMATES RANGE FROM T2.5/35 KT FROM SAB AND T3.5/55 KT FROM TAFB...AND THE LATEST SATCON INTENSITY ESTIMATE FROM THE UNIVERSITY OF WISCONSIN IS 47 KT. BASED ON THESE DATA... THE INITIAL INTENSITY IS RAISED TO 45 KT. HUMBERTO APPEARS TO HAVE BEEN MOVING A BIT FASTER TO THE WEST...AND THE CURRENT MOTION ESTIMATE IS 280/11 KT. THE MID-LEVEL ANTICYCLONE TO THE NORTH OF THE STORM IS FORECAST TO WEAKEN CONSIDERABLY DURING THE NEXT 24 TO 48 HOURS...ALLOWING HUMBERTO TO TURN SHARPLY NORTHWARD BY 72 HOURS. BY THE END OF THE FORECAST PERIOD...ANOTHER HIGH IS FORECAST TO DEVELOP NEAR THE AZORES AND FORCE HUMBERTO TO TURN BACK TO THE WEST-NORTHWEST BY DAY 5. THE NHC OFFICIAL FORECAST HAS BEEN SHIFTED A LITTLE FARTHER EAST AND NORTH OF THE PREVIOUS FORECAST AFTER 36 HOURS DUE TO AN OVERALL EASTWARD TREND IN THE GUIDANCE ENVELOPE. HUMBERTO CONTINUES ON A GRADUAL STRENGTHENING TREND...AND CONDITIONS FAVOR THIS INTENSIFICATION TO CONTINUE FOR THE NEXT 48 TO 72 HOURS. THE INTENSITY GUIDANCE HAS CHANGED LITTLE DURING THE PAST FEW CYCLES...WITH THE SHIPS AND LGEM MODELS SHOWING THE MOST STRENGTHENING AND THE HWRF AND FSU SUPERENSEMBLE BARELY BRINGING HUMBERTO TO HURRICANE STRENGTH. THE NHC OFFICIAL FORECAST IS THEREFORE RELATIVELY UNCHANGED FROM THE PREVIOUS ONE...AND A PEAK IN INTENSITY IS EXPECTED BETWEEN 48 AND 72 HOURS BEFORE HUMBERTO REACHES COLDER WATER AND CONTENDS WITH INCREASING SOUTHWESTERLY VERTICAL SHEAR. HUMBERTO IS BEGINNING TO MOVE AWAY FROM THE CAPE VERDE ISLANDS. THEREFORE...ALL WARNINGS HAVE BEEN DISCONTINUED FOR THOSE ISLANDS. FORECAST POSITIONS AND MAX WINDS INIT 09/2100Z 13.7N 25.3W 45 KT 50 MPH 12H 10/0600Z 14.1N 26.6W 55 KT 65 MPH 24H 10/1800Z 14.8N 28.0W 65 KT 75 MPH 36H 11/0600Z 16.1N 28.8W 75 KT 85 MPH 48H 11/1800Z 18.2N 29.3W 80 KT 90 MPH 72H 12/1800Z 22.5N 30.0W 80 KT 90 MPH 96H 13/1800Z 25.5N 32.0W 65 KT 75 MPH 120H 14/1800Z 26.5N 35.5W 55 KT 65 MPH $$ FORECASTER BERG

Tags: number discussion storm tropical

 

Tropical Storm HUMBERTO Forecast Discussion Number 4

2013-09-09 16:44:28| National Hurricane Center (Atlantic)

Issued at 1100 AM AST MON SEP 09 2013 000 WTNT44 KNHC 091444 TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 4 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 AM AST MON SEP 09 2013 VISIBLE SATELLITE IMAGERY INDICATES THAT HUMBERTO STILL HAS AN ELONGATED LOW-LEVEL CIRCULATION...WITH THE CENTER NEAR THE EASTERN EDGE OF THE DEEP CONVECTION. THIS WAS CONFIRMED BY TWO ASCAT PASSES FROM EARLIER THIS MORNING...BUT THE SCATTEROMETER DATA ALSO INDICATED THAT MAXIMUM WINDS HAVE INCREASED TO 40 KT. THIS ESTIMATE IS ALSO SUPPORTED BY AN AVERAGE OF THE DVORAK ESTIMATES FROM TAFB AND SAB. HUMBERTO IS LOCATED TO THE SOUTH OF A STRONG AZORES HIGH AND CONTINUES TO MOVE 280/10 KT. THE TRACK FORECAST THINKING HAS NOT CHANGED. THE RIDGE IS EXPECTED TO WEAKEN DURING THE NEXT 48 HOURS...GIVING WAY TO TWO CLOSED MID/UPPER-LEVEL LOWS THAT WILL DEVELOP NORTH OF THE CANARY ISLANDS AND OVER THE CENTRAL ATLANTIC. THIS PATTERN SHOULD CAUSE HUMBERTO TO TURN SHARPLY NORTHWARD BY DAY 3. AFTER THAT TIME...HIGH PRESSURE AGAIN BUILDS NEAR THE AZORES...FORCING HUMBERTO TO TURN BACK TO THE WEST-NORTHWEST BY DAY 5. THE GLOBAL MODELS ARE TIGHTLY CLUSTERED THROUGH THE FIRST 48 HOURS BUT THEN DIVERGE WITH THE GFS...FLORIDA STATE SUPERENSEMBLE...GFDL...AND HWRF INDICATING A SHARPER TURN TOWARD THE NORTH. THE GUIDANCE SUPPORTS A SLIGHT NORTHEASTWARD SHIFT FROM THE PREVIOUS FORECAST AT THE LATTER END OF THE FORECAST PERIOD. THE EAST-NORTHEASTERLY SHEAR AFFECTING HUMBERTO IS EXPECTED TO ABATE WITHIN THE NEXT 12 HOURS...AND THE THERMODYNAMICS APPEAR SUFFICIENTLY CONDUCIVE TO SUPPORT ADDITIONAL INTENSIFICATION DURING THE NEXT 72 HOURS. THE SHIPS AND LGEM MODELS CONTINUE TO SHOW THE MOST AGGRESSIVE STRENGTHENING...BUT THAT IS COUNTERED BY THE HWRF...GFDL...AND FLORIDA STATE SUPERENSEMBLE WHICH EITHER DO NOT OR JUST BARELY MAKE HUMBERTO A HURRICANE. THE OFFICIAL FORECAST STILL LIES BETWEEN THESE TWO SCENARIOS AND IS JUST A TAD HIGHER THAN THE INTENSITY CONSENSUS. THE OFFICIAL FORECAST IS GENERALLY AN UPDATE OF THE PREVIOUS ONE...AND IS UNCHANGED FROM DAYS 3 THROUGH 5. FORECAST POSITIONS AND MAX WINDS INIT 09/1500Z 13.6N 24.1W 40 KT 45 MPH 12H 10/0000Z 13.9N 25.5W 50 KT 60 MPH 24H 10/1200Z 14.5N 27.3W 60 KT 70 MPH 36H 11/0000Z 15.5N 28.5W 70 KT 80 MPH 48H 11/1200Z 17.3N 29.1W 75 KT 85 MPH 72H 12/1200Z 21.5N 30.0W 80 KT 90 MPH 96H 13/1200Z 24.5N 31.0W 70 KT 80 MPH 120H 14/1200Z 26.0N 34.5W 60 KT 70 MPH $$ FORECASTER BERG/PASCH

Tags: number discussion storm tropical

 
 

Tropical Storm HUMBERTO Forecast Discussion Number 3

2013-09-09 10:51:28| National Hurricane Center (Atlantic)

Issued at 500 AM AST MON SEP 09 2013 000 WTNT44 KNHC 090851 TCDAT4 TROPICAL STORM HUMBERTO DISCUSSION NUMBER 3 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 AM AST MON SEP 09 2013 SINCE THE PREVIOUS ADVISORY...DEEP CONVECTION WITH A LARGE AREA OF CLOUD TOPS COLDER THAN -80C HAS DEVELOPED MAINLY WEST THROUGH NORTH OF THE LOW-LEVEL CENTER...WITH A FEW STRONG CELLS HAVING RECENTLY FORMED VERY NEAR THE CENTER. THE INITIAL INTENSITY HAS BEEN INCREASED TO 35 KT BASED ON CONSENSUS T2.5/35 KT INTENSITY ESTIMATES FROM BOTH TAFB AND SAB...AND A 34-KT ADT ESTIMATE. AS A RESULT...THE SYSTEM HAS BEEN NAMED HUMBERTO. UPPER-LEVEL OUTFLOW IS GOOD IN ALL QUADRANTS EXCEPT TO THE NORTHEAST WHERE SOME MODEST NORTHEASTERLY SHEAR IS RESTRICTING THE OUTFLOW. HUMBERTO IS MOVING AT 280/10 KT...AND THE CYCLONE SHOULD CONTINUE THIS GENERAL MOTION FOR THE NEXT DAY OR SO. AFTERWARDS...THE GLOBAL AND REGIONAL MODELS ARE IN GOOD AGREEMENT ON AN UPPER-LEVEL LOW OVER THE IBERIAN PENINSULA DIGGING SOUTHWESTWARD ACROSS THE CANARY ISLANDS DURING THE NEXT FEW DAYS AND ERODING THE STRONG SUBTROPICAL RIDGE THAT CURRENTLY EXTENDS FROM THE AZORES SOUTHEASTWARD TO WESTERN AFRICA. THIS RADICAL CHANGE IN THE STEERING CURRENTS IS EXPECTED TO CAUSE HUMBERTO TO MAKE A SHARP TURN TOWARD THE NORTH OR NORTH-NORTHWEST IN 36-48 HOURS AND MAINTAIN THAT MOTION THROUGH 96 HOURS...AFTER WHICH THE RIDGE IS FORECAST TO RE-BUILD TO THE NORTH OF THE CYCLONE AND TURN HUMBERTO WESTWARD OVER HIGHER LATITUDES AND COOLER WATER. THE BULK OF THE MODEL GUIDANCE MADE A SIGNIFICANT SHIFT TO THE EAST THIS CYCLE...AND THE OFFICIAL FORECAST TRACK WAS SHIFTED TO THE RIGHT AS A RESULT...BUT NOT AS FAR TO THE RIGHT AS SOME OF THE MORE RELIABLE MODELS LIKE THE GFS...ECMWF...AND FSSE. MODEST NORTHEASTERLY SHEAR OF ABOUT 12 KT IS FORECAST BY ALL OF MODELS TO WEAKEN TO LESS THAN 8 KT AND REMAIN LOW THROUGH AT LEAST 72 HOURS. SUCH WEAK SHEAR CONDITIONS EXISTING WITHIN A VERY MOIST ENVIRONMENT AND OVER ABOVE AVERAGE SSTS OF AT LEAST 28C WOULD TEND TO FAVOR SIGNIFICANT STRENGTHENING. IN FACT...THE GFS AND ECMWF MODELS DEVELOP AN IMPRESSIVE 200 MB CYCLONIC OUTDRAFT PATTERN BY 72 HOURS...WHICH IS TYPICAL OF A MAJOR HURRICANE. AS A RESULT...THE INTENSITY FORECAST WAS INCREASED OVER THE PREVIOUS ADVISORY AT 72 HOURS...SIMILAR TO THE ICON CONSENSUS MODEL. THE FORECAST REMAINS ON THE CONSERVATIVE SIDE SINCE HUMBERTO WILL BE MOVING OVER SUB-26C SSTS AT THAT TIME. IT IS POSSIBLE...HOWEVER...THAT HUMBERTO COULD STRENGTHEN MORE THAN INDICATED PRIOR TO THE 72-HOUR TIME PERIOD. BY DAYS 4 AND 5...INCREASING SOUTHWESTERLY SHEAR AND COOLER WATERS SHOULD INDUCE GRADUAL WEAKENING. FORECAST POSITIONS AND MAX WINDS INIT 09/0900Z 13.4N 22.8W 35 KT 40 MPH 12H 09/1800Z 13.6N 24.3W 45 KT 50 MPH 24H 10/0600Z 14.1N 26.2W 55 KT 65 MPH 36H 10/1800Z 14.9N 27.8W 60 KT 70 MPH 48H 11/0600Z 16.2N 28.7W 70 KT 80 MPH 72H 12/0600Z 20.0N 29.5W 80 KT 90 MPH 96H 13/0600Z 23.5N 30.5W 70 KT 80 MPH 120H 14/0600Z 25.2N 33.4W 60 KT 70 MPH $$ FORECASTER STEWART

Tags: number discussion storm tropical

 

Tropical Depression NINE Forecast Discussion Number 2

2013-09-09 04:41:52| National Hurricane Center (Atlantic)

Issued at 1100 PM AST SUN SEP 08 2013 000 WTNT44 KNHC 090241 TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 2 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 1100 PM AST SUN SEP 08 2013 SATELLITE IMAGES SHOW THAT DEEP CONVECTION ASSOCIATED WITH THE DEPRESSION HAS INCREASED OVER THE WESTERN PORTION OF THE CIRCULATION THIS EVENING. RECENT ASCAT DATA WAS EXTREMELY HELPFUL IN LOCATING THE CENTER OF THE CYCLONE...WHICH IS STILL LOCATED NEAR THE EASTERN EDGE OF THE MAIN CONVECTIVE CLUSTER DUE TO SOME NORTHEASTERLY SHEAR. THE ASCAT DATA AND SUBJECTIVE DVORAK INTENSITY ESTIMATES FROM TAFB AND SAB SUGGEST THAT THE MAXIMUM WIND SPEED HAS INCREASED TO NEAR 30 KT. THE DEPRESSION IS MOVING WESTWARD AT ABOUT 10 KT. THE CYCLONE IS FORECAST TO CONTINUE MOVING WESTWARD TO WEST-NORTHWESTWARD DURING THE NEXT DAY OR SO...AROUND THE SOUTH SIDE OF A DEEP-LAYER RIDGE OVER THE EASTERN ATLANTIC. AFTER THAT TIME...A MID- TO UPPER-LEVEL LOW...CURRENTLY WELL TO THE NORTHWEST OF THE DEPRESSION IS FORECAST TO DROP SOUTHWARD...CREATING A BREAK IN THE RIDGE ALONG 30W. THIS SHOULD CAUSE THE DEPRESSION TO TURN NORTH-NORTHWESTWARD IN 36 TO 48 HOURS AND THE SYSTEM SHOULD REMAIN ON THAT GENERAL HEADING THROUGH MUCH OF THE REMAINDER OF THE FORECAST PERIOD. THE TRACK GUIDANCE IS IN A LITTLE BETTER AGREEMENT DURING THE FIRST 72 HOURS...BUT AFTER THAT TIME...THERE IS A BIT MORE SPREAD THAN NOTED IN THE PREVIOUS CYCLE. THE GFS...HWRF...AND GFS ENSEMBLE MEAN KEEP THE CYCLONE ON A NORTH OR NORTH-NORTHWEST TRACK ALONG OR EAST OF 30W...WHILE THE ECMWF SHOWS A FASTER NORTHWESTWARD OR WEST-NORTHWESTWARD MOTION AT DAYS 4 AND 5. FOR NOW...THE OFFICIAL FORECAST SPLITS THESE DIFFERENCES AND REMAINS NEAR THE MULTI-MODEL CONSENSUS. THE MODERATE NORTHEASTERLY SHEAR OVER THE DEPRESSION IS EXPECTED TO DECREASE WITHIN THE NEXT 12 TO 24 HOURS. DURING THAT TIME...THE DEPRESSION WILL BE IN A MOIST AIRMASS AND OVER WARM WATERS. THIS SHOULD ALLOW FOR STEADY STRENGTHENING...AND THE UPDATED NHC FORECAST SHOWS A FASTER RATE OF INTENSIFICATION DURING THE NEXT DAY OR SO. THE NHC FORECAST REMAINS MORE CONSERVATIVE THAN THE STATISTICAL GUIDANCE AND IS CLOSE TO THE INTENSITY CONSENSUS. LATE IN THE PERIOD... INCREASING SOUTHWESTERLY SHEAR AND COOLER WATERS ARE LIKELY TO CAUSE SOME WEAKENING. FORECAST POSITIONS AND MAX WINDS INIT 09/0300Z 13.2N 21.9W 30 KT 35 MPH 12H 09/1200Z 13.4N 23.5W 35 KT 40 MPH 24H 10/0000Z 13.7N 25.6W 45 KT 50 MPH 36H 10/1200Z 14.2N 27.6W 55 KT 65 MPH 48H 11/0000Z 15.2N 28.6W 60 KT 70 MPH 72H 12/0000Z 18.5N 30.0W 70 KT 80 MPH 96H 13/0000Z 22.0N 31.5W 70 KT 80 MPH 120H 14/0000Z 23.7N 33.0W 60 KT 70 MPH $$ FORECASTER BROWN

Tags: number discussion tropical depression

 

Tropical Depression NINE Forecast Discussion Number 1

2013-09-08 22:42:59| National Hurricane Center (Atlantic)

Issued at 500 PM AST SUN SEP 08 2013 000 WTNT44 KNHC 082042 TCDAT4 TROPICAL DEPRESSION NINE DISCUSSION NUMBER 1 NWS NATIONAL HURRICANE CENTER MIAMI FL AL092013 500 PM AST SUN SEP 08 2013 SATELLITE IMAGES INDICATE THAT THE LOW PRESSURE SYSTEM BETWEEN THE CAPE VERDE ISLANDS AND THE WEST COAST OF AFRICA HAS DEVELOPED ENOUGH CONVECTIVE ORGANIZATION TO BE DESIGNATED AS A TROPICAL DEPRESSION. THE INITIAL INTENSITY IS SET AT 25 KT BASED ON DVORAK ESTIMATES OF T2.0 FROM TAFB AND T1.5 FROM SAB. THE LOW-LEVEL CENTER APPEARS TO BE ON THE EASTERN EDGE OF THE DEEP CONVECTION DUE TO A LITTLE BIT OF NORTHEASTERLY SHEAR. THE INITIAL MOTION ESTIMATE IS 270/9 KT. THE DEPRESSION IS LOCATED TO THE SOUTH OF A LARGE MID-TROPOSPHERIC ANTICYCLONE CENTERED NEAR THE AZORES...AND THE CURRENT WESTWARD MOTION IS EXPECTED TO CONTINUE FOR ANOTHER 36 HOURS OR SO. AFTER THAT TIME...THE ANTICYCLONE IS FORECAST TO WEAKEN WHILE A CLOSED MID/UPPER-LEVEL LOW DEVELOPS NEAR THE CANARY ISLANDS AND A RIDGE BUILDS WESTWARD FROM AFRICA. THIS PATTERN WILL ALLOW THE DEPRESSION TO TURN RATHER SHARPLY TO THE NORTH-NORTHWEST AFTER 48 HOURS AND CONTINUE THAT TRAJECTORY THROUGH THE END OF THE FORECAST PERIOD. SURPRISINGLY... THE LARGEST SPREAD AMONG THE TRACK GUIDANCE OCCURS WITHIN THE FIRST 48 HOURS OR SO...BUT THE MODELS SEEMS TO CONVERGE BY 72 HOURS. THE NHC OFFICIAL TRACK FORECAST IS CLOSE TO THE MODEL CONSENSUS FOR MUCH OF THE FORECAST. A MOIST AIR MASS...WARM WATERS...AND RELATIVELY LIGHT SHEAR SHOULD ALLOW THE DEPRESSION TO STRENGTHEN AT LEAST GRADUALLY DURING THE NEXT FEW DAYS. HOWEVER...SOME OF THE MODELS...MAINLY THE STATISTICAL-DYNAMICAL GUIDANCE...ARE FAIRLY AGGRESSIVE WITH THE INTENSIFICATION RATE AFTER 24 HOURS. SHIPS AND LGEM HAVE TENDED TO HAVE A HIGH BIAS THIS HURRICANE SEASON...SO THE OFFICIAL FORECAST IS KEPT A BIT LOWER. THE FORECAST DOES...HOWEVER...ANTICIPATE THE CYCLONE BECOMING A HURRICANE BY 72 HOURS. GIVEN THE FORECAST...AND THE UNCERTAINTY WITH HOW BIG THE WIND FIELD WILL GET ONCE THE DEPRESSION BECOMES A TROPICAL STORM...A TROPICAL STORM WARNING HAS BEEN ISSUED FOR THE SOUTHERN CAPE VERDE ISLANDS. FORECAST POSITIONS AND MAX WINDS INIT 08/2100Z 13.1N 20.7W 25 KT 30 MPH 12H 09/0600Z 13.2N 22.1W 30 KT 35 MPH 24H 09/1800Z 13.5N 24.3W 35 KT 40 MPH 36H 10/0600Z 13.9N 26.5W 40 KT 45 MPH 48H 10/1800Z 14.5N 27.9W 55 KT 65 MPH 72H 11/1800Z 17.5N 29.5W 70 KT 80 MPH 96H 12/1800Z 21.0N 31.0W 70 KT 80 MPH 120H 13/1800Z 23.5N 32.5W 65 KT 75 MPH $$ FORECASTER BERG

Tags: number discussion tropical depression

 

Sites : [1215] [1216] [1217] [1218] [1219] [1220] [1221] [1222] [1223] [1224] [1225] [1226] [1227] [1228] [1229] [1230] [1231] [1232] [1233] [1234] next »