[Tropical] Tropical Cyclone Discussion

[EMWIN Server]

WTNT43 KNHC 260856
TCDAT3

HURRICANE SANDY DISCUSSION NUMBER  16
NWS NATIONAL HURRICANE CENTER MIAMI FL       AL182012
500 AM EDT FRI OCT 26 2012

THE STRUCTURE OF SANDY CONTINUES TO EVOLVE...AS SHEAR AND DRY AIR
ASSOCIATED WITH THE UPPER-LOW TO THE SOUTHWEST HAVE DISPLACED MOST
OF THE CONVECTION NORTH OF THE CENTER. AIRCRAFT DATA SHOW THAT
WHILE THE CENTRAL PRESSURE HAS NOT CHANGED MUCH...THE PRESSURE
GRADIENT AND WIND FIELD HAVE BROADENED SUBSTANTIALLY. AS A
RESULT...WINDS FROM FLIGHT LEVEL DO NOT APPEAR TO BE MIXING DOWN TO
THE SURFACE VERY EFFICIENTLY...AND THE INITIAL INTENSITY HAS BEEN
LOWERED TO 70 KT. SANDY IS EXPECTED TO REMAIN NEAR HURRICANE
STRENGTH FOR THE NEXT COUPLE OF DAYS. AFTERWARD...SOME RE-
INTENSIFICATION IS SHOWN AS SANDY INTERACTS WITH A SHORTWAVE
TROUGH...GIVEN THAT THE GLOBAL MODELS SHOW THE LARGE CYCLONE
DEEPENING OFFSHORE OF THE CAROLINAS AND THE MID-ATLANTIC STATES. IT
APPEARS THAT SANDY WILL MAINTAIN SOME TYPE OF WARM SECLUSION
STRUCTURE UNTIL NEAR THE END OF THE PERIOD...ALTHOUGH IT IS
POSSIBLE THAT SANDY COULD BECOME POST-TROPICAL A LITTLE SOONER THAN
INDICATED HERE.

THE INITIAL MOTION ESTIMATE IS TOWARD THE NORTHWEST OR 325/11. AS
SANDY CONTINUES TO INTERACT WITH THE UPPER-LOW IT WILL SLOW DOWN
TODAY AND TONIGHT BEFORE ACCELERATING NORTHEASTWARD ON SATURDAY.
THE NHC TRACK FORECAST IS A LITTLE TO THE LEFT OF THE PREVIOUS ONE
THROUGH 36 HOURS AND LIES BETWEEN THE GFS AND ECMWF MODELS. LATE IN
THE PERIOD...WHILE ALL OF THE GUIDANCE SHOWS SANDY TURNING
NORTHWESTWARD...THERE CONTINUES TO BE LARGE SPREAD IN THE EXACT
TRACK. THE ECMWF...GFDL...HWRF...AND SOME OF THE HFIP GUIDANCE SHOW
A SHARPER TURN TOWARD THE DELMARVA PENINSULA...WHILE THE GFS AND
UKMET SHOW A WIDER TURN WITH A TRACK FARTHER NORTH TOWARD LONG
ISLAND. THE OFFICIAL FORECAST CONTINUES TO LIE BETWEEN THE ECMWF
AND THE TVCA MULTI-MODEL CONSENSUS AT DAYS 4 AND 5...AND IS JUST A
LITTLE TO THE LEFT OF THE PREVIOUS TRACK. USERS ARE REMINDED TO NOT
FOCUS ON THE DETAILS OF THE TRACK FORECAST LATE IN THE PERIOD...AS
SANDY IS EXPECTED TO BRING IMPACTS TO A LARGE PART OF THE U.S. EAST
COAST INTO EARLY NEXT WEEK.

GIVEN THE NEW NHC FORECAST AND THE EXPECTED GROWTH IN THE SIZE OF
THE OUTER WIND FIELD...A TROPICAL STORM WATCH HAS BEEN ISSUED FOR
PORTIONS OF THE COAST OF NORTH AND SOUTH CAROLINA ON THIS ADVISORY.

FORECAST POSITIONS AND MAX WINDS

INIT  26/0900Z 26.3N  76.9W   70 KT  80 MPH
 12H  26/1800Z 27.2N  77.5W   70 KT  80 MPH
 24H  27/0600Z 28.3N  77.5W   65 KT  75 MPH
 36H  27/1800Z 29.7N  76.4W   65 KT  75 MPH
 48H  28/0600Z 31.4N  74.7W   65 KT  75 MPH
 72H  29/0600Z 35.5N  72.5W   70 KT  80 MPH
 96H  30/0600Z 38.5N  74.5W   70 KT  80 MPH
120H  31/0600Z 40.5N  77.5W   50 KT  60 MPH...POST-TROPICAL

$$
FORECASTER BRENNAN



This weather bulletin was brought to you by:
www.nashvilleweather.net