000WTNT44 KNHC 141440TCDAT4TROPICAL STORM NADINE DISCUSSION NUMBER 13NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012ISSUED BY THE HYDROMETEOROLOGICAL PREDICTION CENTER COLLEGE PARK MD1100 AM AST FRI SEP 14 2012NADINE CONTINUES TO SHOW LITTLE CHANGE IN ORGANIZATION ON SATELLITEIMAGERY. THE LOW CLOUD LINES ON VISIBLE IMAGERY SUGGEST THAT THECENTER IS DISPLACED A LITTLE TO THE SOUTHWESTERN PART OF THECENTRAL DENSE OVERCAST. DVORAK INTENSITY ESTIMATES FROM TAFB ANDSAB REMAIN AT 65 AND 55 KT...RESPECTIVELY...SO THE CURRENTINTENSITY ESTIMATE IS KEPT AT 60 KT. THE INTENSITY FORECAST FORNADINE HAS BEEN A BIT CHALLENGING AS THE SYSTEM HAS REMAINED IN AMARGINAL ATMOSPHERIC ENVIRONMENT OVER THE PAST FEW DAYS. A LARGEUPPER-LEVEL TROUGH IN THE VICINITY OF 65-70W LONGITUDE HAS BEENPRODUCING SOUTHWESTERLY SHEAR OVER NADINE. AS THE TROPICAL CYCLONEMOVES NORTHEASTWARD TO EASTWARD OVER THE NEXT FEW DAYS...THEINFLUENCE OF THIS TROUGH WILL DIMINISH. THE GLOBAL MODELS THENSHOW AN UPPER-LEVEL RIDGE MOVING MORE OR LESS IN TANDEM WITH THETROPICAL CYCLONE DURING THE FORECAST PERIOD. THESE MODELS INDICATETHAT SOME DECREASE IN SHEAR IS LIKELY IN A FEW DAYS...WHICH WOULDGIVE NADINE THE OPPORTUNITY FOR SOME STRENGTHENING. THIS ISREFLECTED IN THE OFFICIAL FORECAST...WHICH IS ALSO IN GOODAGREEMENT A CONSENSUS THAT INCLUDES GUIDANCE FROM THE HURRICANEFORECAST IMPROVEMENT PROGRAM...HFIP...MODELS. NADINE HAS MADE ITS EXPECTED TURN TO THE NORTH AND THE INITIALMOTION IS NOW 360/14. THE TROPICAL CYCLONE SHOULD CONTINUE TO MOVEAROUND THE PERIPHERY OF A SUBTROPICAL RIDGE AND TURN EASTWARD INTHE FLOW ON THE NORTH SIDE OF THE RIDGE. BY THE END OF THE FORECASTPERIOD...NADINE IS EXPECTED TO TURN TOWARD THE LEFT AS IT INTERACTSWITH A CYCLONIC CIRCULATION NEAR THE AZORES. THE GUIDANCE ENVELOPEIS BRACKETED BY THE ECMWF TO THE RIGHT/SOUTH AND THE GFDL TO THELEFT/NORTH. THE OFFICIAL TRACK FORECAST IS CLOSE TO THE PREVIOUSONE...AND LIES BETWEEN THE GFS AND THE MULTI-MODEL CONSENSUS TVCN. FORECAST POSITIONS AND MAX WINDSINIT 14/1500Z 28.0N 53.5W 60 KT 70 MPH 12H 15/0000Z 29.6N 53.1W 60 KT 70 MPH 24H 15/1200Z 31.0N 51.5W 60 KT 70 MPH 36H 16/0000Z 31.5N 49.4W 60 KT 70 MPH 48H 16/1200Z 31.8N 46.8W 65 KT 75 MPH 72H 17/1200Z 32.5N 40.5W 65 KT 75 MPH 96H 18/1200Z 34.5N 35.0W 65 KT 75 MPH120H 19/1200Z 36.5N 30.5W 60 KT 70 MPH$$FORECASTER PASCH/HAMRICK/FRACASSO
000WTNT44 KNHC 142033TCDAT4TROPICAL STORM NADINE DISCUSSION NUMBER 14NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012500 PM AST FRI SEP 14 2012A 1624 UTC TRMM PASS SUGGESTS THAT THE CORE CONVECTION MAY BEIMPROVING IN ORGANIZATION...BUT THE MID-LEVEL CENTER IS DISPLACEDABOUT HALF A DEGREE NORTH OF THE LOW-LEVEL CENTER DUE TO VERTICALSHEAR. DVORAK ESTIMATES REMAIN 65 KT FROM TAFB AND 55 KT FROMSAB...AND THE MOST RECENT UW-CIMSS ADT ESTIMATE HAS ACTUALLY FALLENTO 55 KT. THE SATELLITE SIGNATURE SEEMS LARGELY UNCHANGED FROMTHIS MORNING AND DOES NOT LEAD ME TO BELIEVE THAT NADINE HASWEAKENED...SO THE INITIAL INTENSITY IS KEPT AT 60 KT.THE VERTICAL SHEAR IS NOT EXPECTED TO WEAKEN DURING THE FORECASTPERIOD. HOWEVER...THE SHEAR DIRECTION IS FORECAST TO CHANGE FROMSOUTHWESTERLY TO WESTERLY IN A DAY OR TWO...AND THE SHIPS GUIDANCESHOWS THE NEGATIVE CONTRIBUTIONS OF STRONG SHEAR BEING CANCELED OUTBY THE POSITIVE CONTRIBUTIONS OF A MORE FAVORABLE SHEAR DIRECTION. AS A RESULT...THE STATISTICAL GUIDANCE SHOWS LITTLE CHANGE ININTENSITY OVERALL...BUT DOES STILL PRESENT THE POSSIBILITY OFNADINE BECOMING A HURRICANE DURING THE NEXT FEW DAYS. THE HWRFSHOWS NADINE STRENGTHENING SIGNIFICANTLY IN A COUPLE OF DAYS...BUTTHIS SCENARIO APPEARS LESS LIKELY SINCE THE CYCLONE WILL BEAPPROACHING COLDER WATER. THE UPDATED NHC INTENSITY FORECAST ISVERY CLOSE TO THE SHIPS MODEL AND SHOWS A LITTLE MORE WEAKENING BYDAY 5 THAN INDICATED IN THE PREVIOUS ADVISORY.NADINE IS NOW MOVING NORTH-NORTHEASTWARD WITH A MOTION OF 015/12 KT. THE STORM IS ENTERING THE BELT OF MID-LATITUDE WESTERLIES...AND ITSHOULD TURN EASTWARD DURING THE NEXT DAY OR TWO. A NORTHEASTWARDTURN IS THEN FORECAST BY DAYS 4 AND 5 AS NADINE APPROACHES A LARGEDEEP-LAYER LOW NEAR THE AZORES. THE TRACK MODELS HAVE SHIFTEDSOUTHWARD BEYOND 24 HOURS...LEAVING THE PREVIOUS OFFICIAL FORECASTON THE NORTHERN EDGE OF THE GUIDANCE ENVELOPE. THE NEW FORECASTHAS BEEN MOVED A LITTLE SOUTHWARD AS WELL...SHOWING A MOREPRONOUNCED DUE-EAST MOTION FOR A TIME. THE NHC TRACK LIES VERYCLOSE TO THE TIGHTLY CLUSTERED GFS...ECMWF...AND MODEL CONSENSUSTVCA.FORECAST POSITIONS AND MAX WINDSINIT 14/2100Z 28.8N 53.4W 60 KT 70 MPH 12H 15/0600Z 30.1N 52.6W 60 KT 70 MPH 24H 15/1800Z 30.9N 50.4W 60 KT 70 MPH 36H 16/0600Z 31.0N 47.5W 60 KT 70 MPH 48H 16/1800Z 31.1N 44.1W 65 KT 75 MPH 72H 17/1800Z 32.5N 37.5W 65 KT 75 MPH 96H 18/1800Z 35.0N 33.5W 65 KT 75 MPH120H 19/1800Z 37.0N 32.0W 55 KT 65 MPH$$FORECASTER BERG
000WTNT44 KNHC 150246TCDAT4HURRICANE NADINE DISCUSSION NUMBER 15NWS NATIONAL HURRICANE CENTER MIAMI FL AL1420121100 PM AST FRI SEP 14 2012NADINE HAS GOTTEN BETTER ORGANIZED OVER THE PAST FEW HOURS...WITHTHE CORE CONVECTION BECOMING MORE SYMMETRICAL AND MICROWAVE IMAGERYSHOWING THAT THE LOW-LEVEL CENTER IS LOCATED A LITTLE CLOSER TO THEDEEP CONVECTION. SATELLITE INTENSITY ESTIMATES RANGE FROM 65 KTFROM TAFB TO 77 KT FROM SAB AND THE UW-CIMSS ADT. GIVEN THAT SOMETILT STILL APPEARS TO EXIST IN THE CIRCULATION...THE INITIALINTENSITY WILL BE BASED ON THE MORE CONSERVATIVE ESTIMATE FOR THISADVISORY. SOUTHWESTERLY VERTICAL SHEAR OF 25 TO 30 KT IS AFFECTINGNADINE...AND THIS MODERATE TO STRONG SHEAR IS FORECAST TO CONTINUEFOR THE NEXT SEVERAL DAYS. GIVEN THIS MARGINAL ENVIRONMENT...ONLYMINIMAL STRENGTHENING IS FORECAST IN THE SHORT TERM. LATE IN THEPERIOD...THE CYCLONE WILL BE MOVING OVER COOLER WATERS...WHICH INCOMBINATION WITH EVEN STRONGER SHEAR SHOULD LEAD TO GRADUALWEAKENING. THE NEW NHC INTENSITY FORECAST IS CLOSE TO THE DECAYSHIPS MODEL THROUGH 72 HOURS AND TRENDS TOWARD THE LGEM BY DAY 5. THE INITIAL MOTION ESTIMATE IS 025/12...AS NADINE IS MOVING AROUNDTHE NORTHWESTERN SIDE OF THE SUBTROPICAL RIDGE. THE CYCLONE WILLENTER THE MID-LATITUDE WESTERLIES WITHIN 24 HOURS...WHICH SHOULDRESULT IN A QUICK EASTWARD MOTION UNTIL ABOUT DAY 3. A SLOWERMOTION TOWARD THE NORTHEAST IS EXPECTED AT DAYS 4 AND 5 AS ANUPPER-LEVEL TROUGH APPROACHES FROM THE WEST. THE GLOBAL MODELGUIDANCE IS IN GENERALLY GOOD AGREEMENT ON THIS SCENARIO...WHILETHE REGIONAL HURRICANE MODELS APPEAR TO BE OUTLIERS AT THIS TIME.THE NHC FORECAST IS LARGELY AN UPDATE OF THE PREVIOUS ONE...BUTWITH A FASTER FORWARD SPEED THROUGH 72 HOURS. THE NEW NHC TRACK ISVERY CLOSE TO A BLEND OF THE GFS...ECMWF...UKMET...AND THE GEFSENSEMBLE MEAN...AND LIES NEAR THE MIDDLE OF THE GUIDANCE ENVELOPE.NADINE MARKS THE THIRD-EARLIEST FORMATION OF AN EIGHTH HURRICANE FORTHE SEASON IN THE ATLANTIC BASIN...BEHIND 1893 AND 2005. FORECAST POSITIONS AND MAX WINDSINIT 15/0300Z 30.0N 52.8W 65 KT 75 MPH 12H 15/1200Z 30.8N 51.4W 70 KT 80 MPH 24H 16/0000Z 31.2N 48.7W 70 KT 80 MPH 36H 16/1200Z 31.1N 45.5W 70 KT 80 MPH 48H 17/0000Z 31.2N 42.1W 70 KT 80 MPH 72H 18/0000Z 33.0N 36.0W 65 KT 75 MPH 96H 19/0000Z 35.5N 33.0W 60 KT 70 MPH120H 20/0000Z 37.5N 31.5W 50 KT 60 MPH$$FORECASTER BRENNAN
000WTNT44 KNHC 150852TCDAT4HURRICANE NADINE DISCUSSION NUMBER 16NWS NATIONAL HURRICANE CENTER MIAMI FL AL142012500 AM AST SAT SEP 15 2012NADINE HAS CHANGED LITTLE IN ORGANIZATION OVER THE PAST SEVERALHOURS. THE HURRICANE IS MAINTAINING CENTRAL CONVECTIVE BANDING...ALTHOUGH A RECENT AMSU OVERPASS SUGGESTS THAT THE MID-LEVEL CENTERIS DISPLACED TO THE NORTHEAST OR EAST OF THE LOW-LEVEL CENTER.SATELLITE INTENSITY ESTIMATES ARE 77 KT FROM SAB AND 65 KT FROMTAFB...AND RECENT AMSU INTENSITY ESTIMATES FROM CIMSS AND CIRA ARE76 AND 73 KT RESPECTIVELY. DUE TO THE UNCERTAINTY ABOUT THEORGANIZATION...THE INITIAL INTENSITY REMAINS 65 KT. HOWEVER...THISINTENSITY COULD BE A LITTLE CONSERVATIVE.NADINE CONTINUES ITS RECURVATURE INTO THE WESTERLIES WITH AN INITIALMOTION OF 050/13. THE CYCLONE SHOULD MOVE GENERALLY EASTWARD INTHE WESTERLIES FOR THE NEXT 2-3 DAYS...AND THERE IS A CHANCE ITCOULD MOVE A LITTLE SOUTH OF EAST AS SHOWN BY THE ECMWF. AFTERTHREE DAYS...NADINE IS LIKELY TO TURN NORTHEASTWARD AS A DEEP-LAYERLOW PRESSURE SYSTEM FORMS TO THE WEST OVER THE CENTRAL ATLANTIC. THE GFS...GFS ENSEMBLE MEAN...ECMWF...UKMET...AND FLORIDA STATESUPERENSEMBLE ARE NEAR THE CENTER OF THE TRACK GUIDANCE ENVELOPE...AND THE NEW TRACK FORECAST LIES NEAR THESE MODELS. THE NEW FORECASTIS SIMILAR TO THE OLD FORECAST THROUGH 48 HR...AND THEN IS SHIFTEDTO THE EAST OF THE PREVIOUS FORECAST DUE TO AN OVERALL SHIFT IN THETRACK GUIDANCE.NADINE CONTINUES TO EXPERIENCE 25-35 KT OF SOUTHWESTERLY VERTICALWIND SHEAR...AND IT IS UNCLEAR HOW THE CYCLONE HAS BEEN ABLE TOMAINTAIN ITSELF SO WELL IN THIS ENVIRONMENT. :O* ALL GLOBAL MODELGUIDANCE FORECASTS AT LEAST 25-35 KT OF SHEAR TO CONTINUE THROUGHTHE FORECAST PERIOD...WHICH SHOULD PRECLUDE ANY SIGNIFICANTSTRENGTHENING. THE GFS...ECMWF...AND UKMET FORECAST A SHORTWAVETROUGH IN THE WESTERLIES TO INTERACT WITH NADINE IN 72-96 HR...WHICH COULD CHANGE THE INTENSITY AND STRUCTURE. HOWEVER...THERESULTS OF THIS INTERACTION ARE NOT CURRENTLY REFLECTED IN ANY OFTHE INTENSITY GUIDANCE. THE NEW INTENSITY FORECAST IS THE SAME ASTHE PREVIOUS FORECAST AND IS SIMILAR TO THE SHIPS...LGEM...AND THEINTENSITY CONSENSUS.FORECAST POSITIONS AND MAX WINDSINIT 15/0900Z 30.7N 51.4W 65 KT 75 MPH 12H 15/1800Z 31.1N 49.6W 70 KT 80 MPH 24H 16/0600Z 31.1N 46.8W 70 KT 80 MPH 36H 16/1800Z 31.0N 43.6W 70 KT 80 MPH 48H 17/0600Z 31.4N 40.5W 70 KT 80 MPH 72H 18/0600Z 33.0N 35.0W 65 KT 75 MPH 96H 19/0600Z 35.5N 31.5W 60 KT 70 MPH120H 20/0600Z 37.5N 29.5W 50 KT 60 MPH$$FORECASTER BEVEN
000WTNT44 KNHC 151449TCDAT4HURRICANE NADINE DISCUSSION NUMBER 17NWS NATIONAL HURRICANE CENTER MIAMI FL AL1420121100 AM AST SAT SEP 15 2012ALTHOUGH NADINE IS STILL A TILTED HURRICANE...THE CONVECTIVEORGANIZATION IS IMPROVING. A RAGGED EYE FEATURE IS TRYING TO FORMIN VISIBLE IMAGERY...AND RECENT MICROWAVE DATA SHOWED DEEPCONVECTION NEARLY SURROUNDING THE CENTER. CURRENT INTENSITYESTIMATES ARE 65 KT FROM TAFB AND 77 KT FROM SAB...SO THE ADVISORYINTENSITY IS SET AT 70 KT. THIS IS SUPPORTED BY RECENT UW-CIMSSADT ESTIMATES BETWEEN 65 AND 75 KT.NADINE IS QUICKLY RECURVING AND NOW HAS AN ESTIMATED MOTION OF070/13 KT. THE HURRICANE IS ENTERING THE FLOW TO THE SOUTH OF ACOMPLEX DEEP-LAYER LOW PRESSURE SYSTEM LOCATED NEAR THE AZORES...AND NADINE SHOULD TURN EASTWARD AND ACCELERATE DURING THE NEXTCOUPLE OF DAYS. HOWEVER...A BLOCKING PATTERN IS EXPECTED TODEVELOP OVER THE NORTHEASTERN ATLANTIC BY DAY 3 WITH ANOTHERDEEP-LAYER LOW FORMING OVER THE CENTRAL ATLANTIC ON DAYS 4 AND 5. THIS PATTERN CHANGE SHOULD CAUSE NADINE TO TURN NORTHEASTWARD ANDBECOME NEARLY STATIONARY JUST TO THE SOUTHWEST OF THE AZORES BY THEEND OF THE FORECAST PERIOD. MANY OF THE TRACK MODELS ARE SHOWING AFASTER FORWARD SPEED WHILE NADINE IS WITHIN THE WESTERLY FLOW...ANDTHE NEW NHC FORECAST IS A LITTLE FASTER THAN AND SOUTH OF THEPREVIOUS FORECAST DURING THE FIRST 3 DAYS. THE FORECASTS ARE VERYSIMILAR ON DAYS 4 AND 5...WITH THE NEW ONE LYING BETWEEN THE MODELCONSENSUS TVCA AND FLORIDA STATE SUPERENSEMBLE.NADINE IS EXPECTED TO REMAIN IN A HIGHLY SHEARED ENVIRONMENT DURINGTHE ENTIRE FORECAST PERIOD...BUT THE SHEAR DIRECTION IS SUCH THATIT SHOULD TEMPER SIGNIFICANT WEAKENING. THEREFORE...THE NHCINTENSITY FORECAST MAINTAINS NADINE AS A CATEGORY ONE HURRICANE FORTHE NEXT 3 DAYS...WHICH IS SUPPORTED BY MOST OF THE INTENSITYGUIDANCE. COLDER WATER SHOULD ULTIMATELY INDUCE SOME WEAKENING ONDAYS 4 AND 5...AND THAT IS REFLECTED IN THE OFFICIAL FORECAST.FORECAST POSITIONS AND MAX WINDSINIT 15/1500Z 30.9N 49.9W 70 KT 80 MPH 12H 16/0000Z 31.0N 47.8W 70 KT 80 MPH 24H 16/1200Z 30.9N 44.2W 70 KT 80 MPH 36H 17/0000Z 31.0N 40.6W 70 KT 80 MPH 48H 17/1200Z 31.7N 37.5W 70 KT 80 MPH 72H 18/1200Z 34.0N 33.0W 65 KT 75 MPH 96H 19/1200Z 36.5N 31.5W 60 KT 70 MPH120H 20/1200Z 37.0N 31.0W 50 KT 60 MPH$$FORECASTER BERG