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FXHW40 KWBC 151231
PMDHCO
PROGNOSTIC DISCUSSION FOR LONG-LEAD HAWAIIAN OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
830AM EDT THU AUG 15 2024
MONTHLY FORECAST DISCUSSION VALID SEPTEMBER 2024
SEA-SURFACE TEMPERATURES (SSTS) NEAR THE HAWAIIAN ISLANDS (KAUAI, OAHU, MAUI,
AND THE BIG ISLAND) HAVE PREDOMINANTLY BEEN CLOSE TO THE 30-YEAR CLIMATOLOGICAL
AVERAGE DURING THE PAST FEW WEEKS.
FROM JANUARY THROUGH JULY 2024, RAINFALL TOTAL ACCUMULATIONS WERE:
LIHUE AIRPORT 22.55 INCHES (114 PERCENT OF AVERAGE)
HONOLULU AIRPORT 9.56 INCHES (109 PERCENT OF AVERAGE)
KAHULUI AIRPORT 9.17 INCHES (94 PERCENT OF AVERAGE)
HILO AIRPORT 56.66 INCHES (89 PERCENT OF AVERAGE)
THE NCEP CLIMATE FORECAST SYSTEM (CFS) AND OTHER CLIMATE MODELS OF THE NORTH
AMERICAN MULTI-MODEL ENSEMBLE (NMME) GENERALLY PREDICT NEAR-AVERAGE SSTS AROUND
THE HAWAIIAN ISLANDS THROUGH SEPTEMBER 2024. BASED PRIMARILY ON THESE SST
FORECASTS, SURFACE TEMPERATURES ARE INDICATED TO BE EQUAL CHANCES (EC) OF
BELOW, NEAR, AND ABOVE-NORMAL FOR ALL THE ISLANDS THROUGH SEPTEMBER. FOR THE
SEPTEMBER 2024 PRECIPITATION OUTLOOK, BELOW NORMAL PRECIPITATION PROBABILITIES
ARE ELEVATED FOR ALL OF THE ISLAND CHAIN, AS INDICATED BY MOST DYNAMICAL MODEL
FORECASTS, AND CONSISTENT WITH A TRANSITION FROM ENSO-NEUTRAL TO LA NIñA
CONDITIONS OVER THE TROPICAL PACIFIC IN THE NEAR FUTURE.
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
HILO EC 76.4 0.5 B45 8.0 9.3 11.0
KAHULUI EC 79.3 0.4 B50 0.1 0.2 0.5
HONOLULU EC 81.8 0.4 B50 0.4 0.6 0.8
LIHUE EC 79.4 0.3 B50 1.7 1.9 2.6
SEASONAL FORECAST DISCUSSION VALID SON 2024 - SON 2025
REFER TO THE PROGNOSTIC DISCUSSION OF THE LONG-LEAD SEASONAL OUTLOOKS FOR THE
CONUS AND ALASKA FOR A DESCRIPTION OF THE ENSO OUTLOOK AND OTHER CLIMATE
CONDITIONS RELEVANT TO THE SEASONAL OUTLOOK. ENSO-NEUTRAL CONDITIONS ARE
OBSERVED OVER THE PACIFIC OCEAN. EQUATORIAL SSTS ARE ABOVE AVERAGE IN THE WEST
PACIFIC OCEAN, AND NEAR AVERAGE IN THE EAST-CENTRAL AND BELOW AVERAGE IN THE
EASTERN PACIFIC OCEAN. NEGATIVE SUBSURFACE TEMPERATURE ANOMALIES REMAIN AT
DEPTH IN THE CENTRAL PACIFIC OCEAN, WITH SLIGHTLY ABOVE-AVERAGE TEMPERATURES
NEAR THE SURFACE IN THE WESTERN PACIFIC OCEAN. LOW-LEVEL EASTERLY WIND
ANOMALIES WERE OBSERVED OVER THE EAST-CENTRAL AND EASTERN EQUATORIAL PACIFIC
OCEAN, WHILE UPPER-LEVEL WIND ANOMALIES WERE EASTERLY OVER THE EAST-CENTRAL
EQUATORIAL PACIFIC OCEAN AND WESTERLY OVER THE EASTERN EQUATORIAL PACIFIC
OCEAN. ENHANCED CONVECTION AND PRECIPITATION WAS OBSERVED OVER THE FAR WESTERN
PACIFIC AND NEAR THE PHILIPPINES. MOST RECENT DYNAMICAL AND STATISTICAL MODELS
PREDICT ENSO-NEUTRAL TO CONTINUE FOR THE NEXT SEVERAL MONTHS, WITH LA NINA
FAVORED TO EMERGE DURING SEPTEMBER-OCTOBER-NOVEMBER (66% CHANCE) AND PERSIST
THROUGH THE NORTHERN HEMISPHERE WINTER 2024-25 (74% CHANCE DURING
NOVEMBER-DECEMBER-JANUARY).
EQUAL CHANCES (EC) FOR ABOVE, NEAR OR BELOW NORMAL TEMPERATURES ARE INDICATED
FOR KAHULUI AND THE BIG ISLAND IN SON (SEPTEMBER-OCTOBER-NOVEMBER) 2024,
CONSISTENT WITH MOST DYNAMICAL MODEL FORECASTS FROM THE NMME AND C3S. ENHANCED
PROBABILITIES FOR ABOVE NORMAL TEMPERATURES ARE FAVORED OVER KAHULUI AND THE
BIG ISLAND FROM OND (OCTOBER-NOVEMBER-DECEMBER) 2024 THROUGH FMA
(FEBRUARY-MARCH-APRIL) 2025, AND ACROSS HONOLULU AND LIHUE FROM SON 2024 TO FMA
2025, SUPPORTED BY MOST OF THE DYNAMICAL MODEL AND STATISTICAL MODEL
TEMPERATURE FORECAST TOOLS. THE FORECAST SIGNAL WEAKENS AT LONGER LEADS,
THEREFORE EC IS INDICATED FOR HAWAII BEGINNING IN MAM (MARCH-APRIL-MAY) 2025
AND EXTENDING THROUGH LONGER LEADS.
ENHANCED PROBABILITIES FOR BELOW NORMAL PRECIPITATION ARE FORECAST OVER THE
HAWAIIAN ISLANDS (KAUAI, OAHU, MAUI AND THE BIG ISLAND) FROM ASO TO SON 2024,
CONSISTENT WITH MOST DYNAMICAL AND STATISTICAL MODEL FORECASTS. ENHANCED
PROBABILITIES OF ABOVE-NORMAL PRECIPITATION ARE PREDICTED FROM NDJ 2024 TO JFM
2025, CONSISTENT WITH IMPACTS OF A DEVELOPING LA NIñA AND DYNAMICAL MODEL
FORECASTS. DUE TO CONSIDERABLE UNCERTAINTY IN THE PRECIPITATION FORECASTS FROM
DYNAMICAL AND STATISTICAL MODELS, EC IS INDICATED OVER THE HAWAIIAN ISLANDS IN
OND 2024 AND BEGINNING FMA 2025 AND CONTINUING THROUGH LONGER LEADS.
HILO
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
SON 2024 EC 76.2 0.4 B40 24.3 30.2 40.8
OND 2024 A40 75.5 0.4 EC 28.3 34.5 42.0
NDJ 2024 A40 74.2 0.4 A40 26.4 36.6 43.0
DJF 2025 A40 72.8 0.4 A40 19.6 30.2 33.3
JFM 2025 A45 71.8 0.4 A50 22.0 32.0 44.5
FMA 2025 A45 71.7 0.4 A45 24.6 34.1 45.5
MAM 2025 EC 72.0 0.5 EC 22.5 28.4 34.0
AMJ 2025 EC 72.9 0.5 EC 21.4 23.7 29.0
MJJ 2025 EC 74.0 0.4 EC 20.2 27.5 29.1
JJA 2025 EC 75.2 0.4 EC 19.4 27.2 31.4
JAS 2025 EC 76.1 0.4 EC 25.2 28.6 33.4
ASO 2025 EC 76.4 0.4 EC 26.1 28.8 33.3
SON 2025 EC 76.2 0.4 EC 24.3 30.2 40.8
KAHULUI
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
SON 2024 EC 79.1 0.4 B40 2.1 3.3 4.8
OND 2024 A40 77.8 0.4 EC 4.2 5.3 8.1
NDJ 2024 A40 75.9 0.4 A40 5.2 7.6 9.5
DJF 2025 A40 73.8 0.4 A40 4.6 6.9 8.7
JFM 2025 A45 72.5 0.4 A50 4.2 6.2 8.2
FMA 2025 A45 72.3 0.4 A45 3.2 4.1 6.4
MAM 2025 EC 73.0 0.4 EC 2.5 3.5 4.6
AMJ 2025 EC 74.3 0.5 EC 1.2 1.6 2.2
MJJ 2025 EC 76.0 0.5 EC 0.7 1.1 1.8
JJA 2025 EC 77.7 0.4 EC 0.7 1.1 1.5
JAS 2025 EC 79.0 0.4 EC 0.8 1.1 1.6
ASO 2025 EC 79.4 0.4 EC 0.8 1.6 2.5
SON 2025 EC 79.1 0.4 EC 2.1 3.3 4.8
HONOLULU
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
SON 2024 A40 81.4 0.4 B40 2.5 4.0 5.6
OND 2024 A40 80.0 0.4 EC 4.4 6.4 8.5
NDJ 2024 A40 77.7 0.5 A40 3.9 5.6 8.8
DJF 2025 A40 75.3 0.5 A40 3.7 5.6 8.6
JFM 2025 A45 73.9 0.4 A50 2.1 4.6 7.8
FMA 2025 A45 73.8 0.4 A45 1.9 3.2 4.7
MAM 2025 EC 74.8 0.4 EC 1.8 2.6 3.0
AMJ 2025 EC 76.3 0.4 EC 1.2 1.6 1.8
MJJ 2025 EC 78.2 0.4 EC 0.8 1.4 1.6
JJA 2025 EC 79.9 0.4 EC 0.7 0.8 1.3
JAS 2025 EC 81.3 0.4 EC 1.0 1.4 1.7
ASO 2025 EC 81.7 0.4 EC 1.6 2.4 3.1
SON 2025 EC 81.4 0.4 EC 2.5 4.0 5.6
LIHUE
TEMPERATURE PRECIPITATION
FCST AVE LIM FCST BLW MEDIAN ABV
SON 2024 A40 79.1 0.3 B40 9.2 10.0 11.2
OND 2024 A40 77.8 0.3 EC 9.2 11.7 15.6
NDJ 2024 A40 75.7 0.3 A40 8.6 12.1 16.9
DJF 2025 A40 73.6 0.4 A40 7.5 8.4 14.0
JFM 2025 A45 72.2 0.4 A50 6.5 8.8 13.8
FMA 2025 A45 72.1 0.5 A45 5.8 8.4 9.9
MAM 2025 EC 72.8 0.5 EC 5.3 6.6 8.0
AMJ 2025 EC 74.2 0.5 EC 4.7 5.5 6.0
MJJ 2025 EC 76.0 0.5 EC 4.9 5.4 5.9
JJA 2025 EC 77.7 0.4 EC 4.4 5.3 6.9
JAS 2025 EC 79.0 0.3 EC 5.3 6.1 7.8
ASO 2025 EC 79.4 0.3 EC 6.2 7.9 8.4
SON 2025 EC 79.1 0.3 EC 9.2 10.0 11.2
FORECASTER: LUKE HE
ANOMALIES ARE BASED ON THE 1991-2020 MEANS.
CLARIFICATION: EC INDICATED EQUAL CHANCES THAT THE PREDICTED PARAMETER WILL
FALL INTO ANY ONE OF THE THREE CATEGORIES, WHOSE BOUNDARIES ARE SPECIFIC IN THE
TABLES ABOVE. A FORECAST SPECIFICATION OF EC MEANS THERE IS NO PARTICULATE TILT
OF THE ODDS TOWARD ABOVE NORMAL OR BELOW NORMAL CONDITIONS IN THE OUTLOOK. FOR
EXAMPLE A40 MEANS A 40% CHANCE THAT THE AVERAGE TEMPERATURE OR TOTAL
PRECIPITATION WILL BE IN THE ABOVE NORMAL CLASS, B40 MEANS A 40% CHANCE THAT
THE AVERAGE TEMPERATURE OR TOTAL PRECIPITATION WILL BE IN THE BELOW NORMAL
CLASS, AND N35 MEANS A 35% PROBABILITY THAT THE AVERAGE TEMPERATURE OR TOTAL
PRECIPITATION WILL BE IN THE NEAR NORMAL CLASS. WHEN EC IS SPECIFIED, ALL
CATEGORIES ARE EQUALLY LIKELY.
NOTE - THESE OUTLOOKS ARE INTENDED FOR USE PRIOR TO THE START OF THE VALID
PERIODS. WITHIN ANY VALID PERIOD, OBSERVATIONS AND SHORTER RANGE FORECASTS
SHOULD BE CONSULTED. ALSO, THIS SET OF OUTLOOKS WILL BE SUPERSEDED BY THE
ISSUANCES OF THE NEW SET NET MONTH, ON THU SEP 19, 2024.
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