154
WTPA42 PHFO 240843
TCDCP2
TROPICAL STORM NOLO DISCUSSION NUMBER 15
NWS CENTRAL PACIFIC HURRICANE CENTER HONOLULU HI EP152026
ISSUED BY NWS NATIONAL HURRICANE CENTER MIAMI FL
1100 PM HST WED SEP 23 2026
NOLO'S CONVECTIVE ORGANIZATION HAS GRADUALLY IMPROVED DURING THE
PAST SEVERAL HOURS, WITH A CURVED BAND OF PERSISTENT DEEP CONVECTION
TIGHTENING AROUND THE CIRCULATION CENTER. THE LATEST SUBJECTIVE
DVORAK INTENSITY ESTIMATES FROM JTWC AND HFO ARE BOTH T2.5/35 KT,
WHILE OBJECTIVE INTENSITY ESTIMATES RANGE FROM 35 TO 55 KT. GIVEN
THE IMPROVED CONVECTIVE ORGANIZATION AND THE HIGHER OBJECTIVE
ESTIMATES, THE INITIAL INTENSITY IS RAISED TO 45 KT.
NOLO HAS SLOWED CONSIDERABLY AND APPEARS TO BE MAKING ITS
ANTICIPATED NORTHWARD TURN, WITH AN INITIAL MOTION OF 360/2 KT. A
WEAKENING SUBTROPICAL RIDGE NORTHEAST OF HAWAII SHOULD ALLOW NOLO TO
CONTINUE MOVING SLOWLY NORTHWARD INTO THURSDAY, FOLLOWED BY A
NORTH-NORTHEASTWARD MOTION AS AN UPPER-LEVEL TROUGH DEEPENS
NORTHWEST OF THE HAWAIIAN ISLANDS. AS THE TROUGH SHIFTS WESTWARD AND
THE SUBTROPICAL RIDGE REBUILDS NORTH OF THE CYCLONE, NOLO IS
FORECAST TO MAKE A SHARP WESTWARD TURN FRIDAY NIGHT INTO SATURDAY.
THE LATEST GDMI AND HCCA GUIDANCE HAS SHIFTED SLIGHTLY NORTHWARD,
BRINGING THE SYSTEM CLOSER TO THE BIG ISLAND. GIVEN THE RUN-TO-RUN
INCONSISTENCIES IN THE GUIDANCE, THE NHC TRACK FORECAST IS
ESSENTIALLY AN UPDATE OF THE PREVIOUS ADVISORY AND SHOWS NOLO
PASSING SOUTH OF THE BIG ISLAND ON SATURDAY BEFORE CONTINUING
WESTWARD SOUTH OF THE SMALLER HAWAIIAN ISLANDS THROUGH THE LATTER
PORTION OF THE WEEKEND. HOWEVER, CONSIDERABLE UNCERTAINTY REMAINS
REGARDING THE INFLUENCE OF THE DEEPENING UPPER-LEVEL TROUGH ON
NOLO'S TRACK, AS WELL AS THE TIMING AND STRENGTH OF THE SUBTROPICAL
RIDGE REBUILDING NORTH OF THE CYCLONE. EVEN RELATIVELY SMALL
DIFFERENCES IN THE EVOLUTION OF THESE STEERING FEATURES COULD
SIGNIFICANTLY ALTER THE TIMING AND LOCATION OF NOLO'S SHARP WESTWARD
TURN AND, ULTIMATELY, HOW CLOSE ITS CENTER PASSES TO THE BIG ISLAND.
A TRACK CLOSER TO THE BIG ISLAND COULD ALSO RESULT IN INTERACTIONS
WITH THE ISLAND'S TERRAIN THAT COULD FURTHER INFLUENCE THE CYCLONE'S
SUBSEQUENT MOTION. GIVEN THESE UNCERTAINTIES, CONFIDENCE IN THE
TRACK FORECAST REMAINS LOWER THAN NORMAL.
ENVIRONMENTAL CONDITIONS REMAIN FAVORABLE FOR STRENGTHENING, WITH
VERY WARM SEA SURFACE TEMPERATURES AND PLENTY OF MID-LEVEL MOISTURE
ALONG THE FORECAST TRACK. HOWEVER, AROUND 10 KT OF EASTERLY VERTICAL
WIND SHEAR MAY TEMPER THE RATE OF INTENSIFICATION DURING THE NEXT 24
H OR SO. AS THE SHEAR RELAXES AND NOLO CONTINUES TO DEVELOP AN INNER
CORE, A FASTER RATE OF INTENSIFICATION IS FORECAST WHILE THE CYCLONE
MOVES NORTHWARD TO NORTH-NORTHEASTWARD DURING THE NEXT COUPLE OF
DAYS. THESE CONDITIONS COULD SUPPORT A PERIOD OF RAPID
INTENSIFICATION, AND NOLO IS FORECAST TO BECOME A HURRICANE BY
THURSDAY NIGHT AND REACH MAJOR HURRICANE STRENGTH ON SATURDAY AS IT
PASSES SOUTH OF THE BIG ISLAND. THE LATEST NHC INTENSITY FORECAST
HOVERS NEAR THE UPPER END OF THE GUIDANCE ENVELOPE THROUGHOUT THE
FORECAST PERIOD. A TRACK CLOSER TO THE BIG ISLAND COULD
SUBSTANTIALLY INCREASE THE THREAT OF DAMAGING WINDS, PARTICULARLY
OVER HIGHER TERRAIN, ALONG EXPOSED RIDGES, AND IN AREAS DOWNWIND OF
THE RIDGES.
KEY MESSAGES:
1. TROPICAL STORM NOLO IS EXPECTED TO STRENGTHEN INTO A HURRICANE BY
THURSDAY NIGHT AS IT MOVES NORTHWARD TO NORTH-NORTHEASTWARD,
POTENTIALLY MAKING ITS CLOSEST APPROACH TO THE BIG ISLAND OF HAWAII
AS A MAJOR HURRICANE ON SATURDAY. A HURRICANE WATCH REMAINS IN
EFFECT FOR THE BIG ISLAND, AND RESIDENTS THERE SHOULD FOLLOW ADVICE
GIVEN BY LOCAL OFFICIALS, INCLUDING EVACUATING IF TOLD TO DO SO.
2. THE TIME TO PREPARE FOR SIGNIFICANT HEAVY RAIN AND FLOODING
IMPACTS ON THE BIG ISLAND IS NOW, AS HEAVY RAIN BECOMES MORE LIKELY
BY THURSDAY AND FRIDAY. PERIODS OF HEAVY RAIN ARE LIKELY TO CONTINUE
ACROSS THE BIG ISLAND AND MAUI THROUGH THE WEEKEND.
LIFE-THREATENING, CATASTROPHIC FLOODING AND MUDSLIDES ARE POSSIBLE,
ESPECIALLY IN AREAS OF STEEP TERRAIN ACROSS THE BIG ISLAND AND MAUI.
ACROSS THE REMAINDER OF HAWAII, LESSER RAINFALL TOTALS ARE EXPECTED,
WITH ISOLATED FLOODING POSSIBLE.
3. LARGE AND DAMAGING WAVES ARE POSSIBLE ALONG PORTIONS OF THE
BIG ISLAND'S COASTLINE INTO THE WEEKEND.
4. INTERESTS ELSEWHERE IN HAWAII SHOULD CLOSELY MONITOR THE LATEST
FORECAST UPDATES AND ENSURE THAT THEY HAVE THEIR PREPAREDNESS PLANS
IN PLACE.
FORECAST POSITIONS AND MAX WINDS
INIT 24/0900Z 14.9N 156.0W 45 KT 50 MPH
12H 24/1800Z 15.1N 156.0W 55 KT 65 MPH
24H 25/0600Z 15.8N 155.7W 65 KT 75 MPH
36H 25/1800Z 16.7N 155.4W 75 KT 85 MPH
48H 26/0600Z 17.3N 155.3W 85 KT 100 MPH
60H 26/1800Z 17.6N 155.8W 95 KT 110 MPH
72H 27/0600Z 17.6N 157.1W 105 KT 120 MPH
96H 28/0600Z 18.1N 160.8W 105 KT 120 MPH
120H 29/0600Z 20.3N 163.7W 95 KT 110 MPH
FORECASTER GIBBS
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