070
WTPA44 PHFO 110234
TCDCP4
POST-TROPICAL CYCLONE LOWELL DISCUSSION NUMBER 60
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP122026
ISSUED BY NWS NATIONAL HURRICANE CENTER MIAMI FL
500 PM HST THU SEP 10 2026
IT HAS NOW BEEN ROUGHLY 24 HOURS SINCE LOWELL PRODUCED MORE THAN
JUST PATCHES OF DEEP CONVECTION ON ITS NORTHEAST SIDE. THIS ACTIVITY
HAS LACKED MUCH ORGANIZATION OVER THIS TIME SPAN, WITH CONTINUED
WESTERLY VERTICAL WIND SHEAR KEEPING THE LOW-LEVEL CIRCULATION
EXPOSED. GIVEN THAT LOWELL HAS LACKED ORGANIZED CONVECTION NEAR ITS
CENTER FOR ABOUT A DAY, AND WITH MOST OF THE GLOBAL AND
HURRICANE-REGIONAL MODEL GUIDANCE NOT SHOWING A RETURN OF DEEP
CONVECTION FOR AT LEAST ANOTHER 24 H, LOWELL IS BEING DECLARED A
POST-TROPICAL CYCLONE THIS ADVISORY. THE MAXIMUM SUSTAINED WINDS
REMAIN 45 KT, HOWEVER, BASED ON SCATTEROMETER DATA RECEIVED AFTER
THE PRIOR ADVISORY.
THE POST-TROPICAL LOW IS STILL MOVING WESTWARD AT 270/12 KT. MUCH OF
THE FORECAST REASONING HAS NOT CHANGED DESPITE THE CYCLONE'S STATUS
CHANGE, WITH A DEEP-LAYER CUTOFF LOW EXPECTED TO PICK UP THE
POST-TROPICAL LOW, PINWHEELING IT AROUND TO THE NORTHWEST, WEST,
THEN SOUTHWARD IN THE 24-72 H PERIOD. THERE CONTINUE TO BE
DIFFERENCES IN THE MODEL GUIDANCE ON HOW SHARP OF A CYCLONIC TURN
AROUND THE UPPER-LEVEL LOW THERE WILL BE, BUT ULTIMATELY THE
GUIDANCE SHOWS THE POST-TROPICAL LOW BEING DEPOSITED BACK SOUTH
AFTER THE UPPER-LEVEL FEATURE BYPASSES IT TO THE EAST IN 72-96 H.
AS MENTIONED ABOVE, MOST OF THE MODEL GUIDANCE DOES NOT SHOW DEEP
CONVECTION RETURNING NEAR THE POST-TROPICAL CYCLONE FOR THE NEXT DAY
OR SO. HOWEVER, AN UPPER-LEVEL CUTOFF LOW IS STILL FORECAST TO DROP
SOUTHWARD AND INDUCE SOME SHEARED CONVECTION THIS WEEKEND. HOWEVER,
GIVEN THE DISORGANIZED STATE OF THE POST-TROPICAL CYCLONE, THIS
BRIEF PERIOD OF FAVORABLE CONVECTIVE FORCING DOES NOT APPEAR TO LAST
LONG ENOUGH FOR THE SYSTEM TO REDEVELOP INTO A TROPICAL CYCLONE,
ESPECIALLY GIVEN THAT THE GFS AND ECMWF-BASED SHIPS GUIDANCE SHOWS
VERTICAL WIND SHEAR REMAINING IN THE 30-40 KT RANGE. AFTER THE
UPPER-LEVEL CUTOFF PASSES IT BY TO THE EAST, THE LOW IS EXPECTED TO
SLOWLY FILL, WITH MUCH OF THE MODEL GUIDANCE SHOWING THE LOW OPENING
UP INTO A TROUGH BY 120 H, WHICH IS NOW REFLECTED IN THE NHC
FORECAST.
THIS IS THE FINAL ADVISORY ON LOWELL UNLESS REGENERATION OCCURS. FOR
ADDITIONAL INFORMATION ON THE POST-TROPICAL LOW PLEASE SEE HIGH SEAS
FORECASTS ISSUED BY THE NATIONAL WEATHER SERVICE, UNDER AWIPS HEADER
NFDHSFEPI, WMO HEADER FZPN01 KWBC, AND ON THE WEB AT
OCEAN.WEATHER.GOV/SHTML/NFDHSFEPI.PHP
KEY MESSAGES:
1. POST-STORM SAFETY: FOLLOW ADVICE OF LOCAL OFFICIALS AND AVOID
AREAS OF DOWNED POWER LINES AND FLOODING. ENSURE GENERATORS ARE
PROPERLY VENTILATED AND PLACED OUTSIDE AT LEAST 20 FEET AWAY FROM
DWELLINGS AND GARAGES TO AVOID CARBON MONOXIDE POISONING. DURING
CLEAN UP, BE CAREFUL WHEN USING CHAINSAWS AND POWER TOOLS. DRINK
PLENTY OF WATER TO AVOID HEAT EXHAUSTION.
FORECAST POSITIONS AND MAX WINDS
INIT 11/0300Z 29.0N 169.9W 45 KT 50 MPH...POST-TROPICAL
12H 11/1200Z 29.2N 171.3W 40 KT 45 MPH...POST-TROPICAL
24H 12/0000Z 30.6N 172.0W 40 KT 45 MPH...POST-TROPICAL
36H 12/1200Z 32.7N 172.8W 45 KT 50 MPH...POST-TROPICAL
48H 13/0000Z 34.0N 175.0W 40 KT 45 MPH...POST-TROPICAL
60H 13/1200Z 33.6N 176.7W 35 KT 40 MPH...POST-TROPICAL
72H 14/0000Z 32.9N 177.0W 30 KT 35 MPH...POST-TROP/REMNT LOW
96H 15/0000Z 31.5N 176.6W 25 KT 30 MPH...POST-TROP/REMNT LOW
120H 16/0000Z...DISSIPATED
FORECASTER PAPIN
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