478
WTNT45 KNHC 280845
TCDAT5
TROPICAL STORM TAMMY DISCUSSION NUMBER 36
NWS NATIONAL HURRICANE CENTER MIAMI FL AL202023
500 AM AST SAT OCT 28 2023
TAMMY CONTINUES TO BE A SHEARED SYSTEM WITH LIMITED CONVECTION THIS
MORNING. CLOUD TOPS HAVE BEEN WARMING SINCE LAST EVENING, WITH ONLY
OCCASIONAL BURST NEAR THE CENTER. A PARTIAL SCATTEROMETER PASS THAT
ARRIVED SHORTLY AFTER THE PREVIOUS ADVISORY, DEPICTED WINDS ON THE
EASTERN SIDE OF THE SYSTEM WERE 40-45 KNOTS. THIS ASCAT DATA IS IN
GOOD AGREEMENT WITH THE LATEST TAFB SATELLITE INTENSITY ESTIMATE OF
T3.0/45 KT. THEREFORE, THE INITIAL INTENSITY IS LOWERED TO 45 KT
BASED ON THIS DATA AND THE DEGRADED SATELLITE PRESENTATION.
STRONG VERTICAL WIND SHEAR IS EXPECTED TO CONTINUE OVER TAMMY THE
NEXT FEW DAYS, WHICH SHOULD RESULT IN FURTHER WEAKENING. WHILE SEA
SURFACE TEMPERATURES ARE MARGINAL, THERE IS INCREASINGLY DRY AIR
ALONG THE FORECAST TRACK. THE GFS AND ECMWF MODEL-SIMULATED
SATELLITE DATA INDICATE TAMMY COULD BE COMPLETELY DEVOID OF
CONVECTION WITHIN 36- 48 HOURS. THE UPDATED NHC INTENSITY FORECAST
IS LOWER THAN THE PREVIOUS ONE, FOLLOWING THE LATEST CONSENSUS AIDS.
POST-TROPICAL REMNANT LOW STATUS IS NOW SHOWN IN 48 H, ALTHOUGH THIS
COULD OCCUR EVEN SOONER THAN FORECAST.
TAMMY HAS TURNED NORTHWARD AND THEN NORTHEASTWARD OVERNIGHT. THE
LONG-TERM MOTION OF TAMMY IS NORTHEAST AT 50/6 KT. A FASTER EASTWARD
TO SOUTHEASTWARD MOTION IS FORECAST THROUGHOUT THE WEEKEND AS TAMMY
MOVES AROUND THE NORTHERN AND EASTERN SIDES OF A MID-LEVEL RIDGE.
AS THE CYCLONE WEAKENS AND BECOMES MORE SHALLOW IT IS FORECAST TO
SLOW DOWN AND TURN SOUTHWARD-SOUTHWESTWARD EARLY NEXT WEEK AS THE
RIDGE BECOMES POSITIONED TO ITS WEST. THE NHC TRACK FORECAST IS A
LITTLE FASTER THAN THE PREVIOUS, AND LIES BETWEEN THE SIMPLE AND
CORRECTED CONSENSUS AIDS.
FORECAST POSITIONS AND MAX WINDS
INIT 28/0900Z 33.0N 60.1W 45 KT 50 MPH
12H 28/1800Z 33.0N 58.7W 40 KT 45 MPH
24H 29/0600Z 32.6N 56.0W 35 KT 40 MPH
36H 29/1800Z 31.7N 53.1W 35 KT 40 MPH
48H 30/0600Z 30.4N 50.6W 30 KT 35 MPH...POST-TROP/REMNT LOW
60H 30/1800Z 28.9N 49.5W 25 KT 30 MPH...POST-TROP/REMNT LOW
72H 31/0600Z 27.5N 50.8W 20 KT 25 MPH...POST-TROP/REMNT LOW
96H 01/0600Z 27.9N 53.1W 20 KT 25 MPH...POST-TROP/REMNT LOW
120H 02/0600Z...DISSIPATED
FORECASTER KELLY
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