Hawaii and USAPI Climate Summary

This webpage serves as a digital version of the quarterly "Hawaii and US Pacific Islands Region Climate Impacts and Outlook". The quarterly outlook draws on the PEAC Climate Center's "Pacific ENSO Update" quarterly newsletter and other sources to bring together seasonal predictions and projections alongside information on recent impacts of weather and climate events in a concise and accessible format. The top four tabs (below) mirror the content that can be found in the current outlook.

This webpage also provides access to information used to develop the quarterly outlook in the form of a “dashboard” that aggregates climate variability-related content via links to products and information from a mix of primarily US agencies, institutions, and organizations.

Climate Impacts and Outlook

Hawaii and U.S. Pacific Islands Region
3rd Quarter 2023

Significant Events and Impacts for Previous Quarter by Locale

pacific overlook

Highlights for Hawaii and the U.S. Affiliated Pacific Islands

Significant Events and Impacts for Previous Quarter by Sector

Weather Research & Forecasting Model (WRF) – model simulation (2-km resolution) of 10-meter wind speed (knots) and wind direction across Maui on 8/8/23 4:00 p.m. HST. The simulation shows strong downslope winds (35 knots = 40 mph) out of the northeast impacting West Maui. Source: Department of Atmospheric Sciences, UH, Manoa.

Landsat 8 satellite image of active fires (in yellow) on Maui, including Lahaina, at 10:25 p.m. on 8/8/23. The image is composed of shortwave infrared light observed by the Operational Land Imager on Landsat 8. Source: NASA Earth Observatory.

Post-fire aerial photograph of destruction at the Lahaina Harbor. Image credit: The Maui News.

Wildfires – On the evening of 8/8/23, an outbreak of wildfires impacted parts of Maui with catastrophic effects occurring in the historic town of Lahaina, West Maui. The wildfires quickly spread across Lahaina decimating the town with ~97 people perishing and over 2,200 structures either damaged or destroyed. It is estimated that nearly 86% of Lahaina was destroyed in the fires leaving several thousand residents displaced and in need of shelter. In addition, areas of the upper Kula region of Maui were also affected by the wildfires with 19 homes destroyed, according to the County of Maui. In terms of the antecedent climate conditions in Maui during the summer months (prior to the fires), below-normal rainfall was observed in West Maui and in Upcountry Maui causing the U.S. Drought Monitor to introduce areas of moderate to severe drought on the weekly map starting in mid-July with drought conditions intensifying during early August. Looking at observational station data for Lahaina and Kula preceding the wildfire outbreak, the Lahainaluna observing station (NWS COOP #51578) recorded 0.40 in. (25% of normal) of rainfall during Jun-Aug 2023 period, while the Kula Experiment Station site observed 0.37 in. (25% of normal), according to the NOAA Regional Climate Center’s SC-ACIS system and the National Weather Service (NWS) Forecast Office in Honolulu. In terms of the vegetation conditions, Normalized Difference Vegetation Index (NDVI) data (metric used to quantifying vegetation greenness, density, and plant health) from the NASA/USGS Landsat satellite for early August 2023 revealed areas of abnormally dry vegetation (as compared to long-term averages for the period) around West Maui and Upcountry Maui. Lastly, observed maximum wind gusts on the day of the wildfire outbreak (8/8/23) reached 62 mph at Maalaea Bay, according to the NWS. In response to the devastating fires, President Biden officially declared a major disaster on 8/10/23 ordering Federal aid to supplement state and local recovery efforts in the areas affected by the wildfires


Water Resources – In Majuro (RMI), reservoir storage reached 88% of total capacity (36,000,000 gallons) on 8/31/23. In Maui, Oahu, and Kauai, observed monthly average streamflows (August) on numerous rivers and streams were well-below normal (ranging from the 2nd-20th percentile), according to the U.S. Geological Survey.


Facilities and Infrastructure – In American Samoa, heavy rainfall (7/12-18) caused a landslide in the village of Amanave on the west side of the island of Tutuila on 7/18/23.



Regional Climate Overview for Previous Quarter

Seasonal sea surface temperature anomaly map for 6/4/23 to 9/2/23 (left) and 3-month seasonal precipitation anomalies for the June–August 2023 period (right). Areas with above-normal precipitation are depicted in green while areas with below-normal amounts are depicted in brown. Source: NOAA PSL, IRI, NOAA CPC CAMS-OPI.



By the end of the JJA period, SSTs were above-normal across the central and eastern tropical Pacific Ocean with an El Niño Advisory in effect (9/14/23). According to the latest NOAA CPC update (9/14/23), Niño region SST departures were above normal across the equatorial Pacific Ocean with Niño 3.4 at 1.6ºC, Niño 3 at 2.2ºC, Niño 1+2 at 2.9ºC, and Niño 4 at 1.1ºC.

During the JJA period, below-normal sea levels were observed across areas of the northwestern tropical Pacific Ocean with the highest sea level anomalies in USAPI occurring around Palau and western FSM (5-10 cm below normal) as well as in areas of the northeastern Pacific Ocean away from the coast. Elsewhere in the Pacific, above-normal sea levels were observed across the central and eastern equatorial Pacific (5-15 cm above normal) by August. Overall, the basin-wide sea level pattern was consistent with El Niño conditions and the exceptionally negative Pacific Meridional Mode, according to the University of Hawaii Sea Level Center.

During the JJA period, most of the USAPI was drought-free, with exception of short-term drought development observed in American Samoa in August. Median precipitation for the JJA period was above normal across much of the USAPI with exception of areas of RMI and American Samoa. For JJA, Airai (Palau) recorded 57.11 in. (109% of normal). In FSM, Yap observed 61.37 in. (139% of normal, 3rd wettest), Kapingamarangi 52.77 in. (138% of normal, wettest on record), Pohnpei 71.91 in. (155% of normal, wettest on record), Lukunor 35.77 in. (87% of normal), Kosrae 58.69 in. (128% of normal), and Chuuk 44.52 in. (115% of normal). In the Mariana Islands, Saipan observed 26.09 in. (106% of normal) and Guam 37.16 in. (109% of normal). In the RMI, Majuro observed 30.5 in. (89% of normal) for JJA, while Kwajalein logged 22.24 in. (82% of normal). In American Samoa, precipitation was below normal (13.71 in.,78% of normal, 6th driest August on record) at Pago Pago. Across much of the Hawaiian Islands, below-normal rainfall conditions prevailed during the JJA period, with moderate to severe drought conditions observed across areas of the island chain, according to the U.S. Drought Monitor. For the JJA period, Lihue observed 3.22 in. (55% of normal), Honolulu 0.7 in. (38% of normal), Molokai 0.8 in. (39% of normal), Kahului 0.67 in. (54% of normal), Kailua Kona 0.84 in. (47% of normal), and Hilo 14.7 in. (53% of normal).

During the MAM period, most of the USAPI were drought-free, with exception of short-term drought conditions observed in RMI in Wotje (Mar-Apr), Kwajalein (Mar-Apr), and in FSM in Kapingamarangi during March. Median precipitation for the MAM period was above normal across much of the USAPI. For MAM, Airai (Palau) recorded 38.87 in. (129% of normal). In FSM, Yap observed 22.4 in. (116% of normal), Kapingamarangi 35.43 in. (138% of normal), Pohnpei 69.82 in. (126% of normal, 6th wettest May on record), Lukunor 24.73 in. (70% of normal, 6th driest MAM on record), Kosrae 47.3 in. (87% of normal), and Chuuk 45.8 in. (133% of normal). In the Mariana Islands, Saipan observed 13.01 in. (215% of normal, 3rd wettest MAM on record) and Guam 41.61 in. (390% of normal, wettest MAM and May on record). In the RMI, Majuro observed 35.7 in. (139% of normal) for MAM, while Kwajalein logged 37.48 in. (217% of normal). In American Samoa, precipitation was above normal (41.78 in.,126% of normal) at Pago Pago. Across much of the Hawaiian Islands, above-normal rainfall was observed for the MAM period, with drought-free conditions observed across most of the island chain with exception of moderate drought observed in areas of Central/West Maui in April and in the North Kohala district on the Big Island during May, according to the U.S. Drought Monitor. For the MAM period, Lihue observed 14.81 in. (151% of normal), Honolulu 5.49 in. (139% of normal), Molokai 6.5 in. (114% of normal), Kahului 3.02 in. (65% of normal), Kailua Kona 3.42 in. (153% of normal), and Hilo 21.96 in. (74% of normal).

In the Northwest Pacific region (west of 135ºE), tropical cyclone (TC) activity has been above normal for the 2023 season, with 12 named storms with an Accumulated Cyclone Energy (ACE) Index of 211 (normal 143) by 9/5/23. In the Northeast Pacific region (east of 180ºW), the ACE Index has been above normal (105.6 by 9/5/23—normal for the date 86.9) with 10 named storms since late June including the powerful, long-lasting Hurricane Dora (~8/1-8/12 as a hurricane/typhoon) which developed in the Eastern Pacific during early August of the coast of El Salvador. Dora tracked westward across the Pacific Ocean intensifying to a Category 4 hurricane with sustained winds of 145 mph on 8/5/23. The hurricane eventually crossed the International Date Line (8/11) and was reclassified as Typhoon Dora.


Regional Climate Outlook for Next Quarter

Forecast for each of the three possible ENSO categories for the next 8 overlapping 3-month seasons. Blue bars show the chances of La Niña, gray bars the chances for neutral, and red bars the chances for El Niño (left) and ENSO forecast model predictions (right).
Source: NOAA CPC, Columbia University IRI.

According to the latest ENSO prediction model simulations (above right), there is relatively strong agreement amongst the dynamical models in the IRI ENSO prediction plume of gradual strengthening of positive SST anomalies during the Sept-Nov 2023 period and continuation into the Northern Hemisphere winter (>95% chance through January-March 2024) in association with the on-going El Niño event. Moreover, the probability of a “strong” El Niño to develop (Nov 2023-Jan 2024) has increased to 71%, according to NOAA CPC.

NOAA’s Coral Reef Watch four-month coral bleaching heat stress outlook (Sept 2023-Dec 2023) calls for a high probability (90%) of high heat stress (Alert Level 1-2) developing in areas of the tropical Pacific Ocean extending from ~125º W to ~160º E. Moreover, a heat stress Watch is forecast for areas of RMI, eastern FSM, Guam, CNMI and portions of the Hawaiian Islands.

NOAA Coral Reef Watch four-month coral bleaching heat stress outlook for Sept-Dec 2023. Red and maroon colors represent areas with a high probability of coral bleaching heat stress Alert Levels 1 & 2.
Source: NOAA NESDIS.

During the period of September 2023 through November 2023, above-normal precipitation is forecasted for areas of USAPI, including most of FSM (Chuuk, Kosrae, Pohnpei) and RMI (Kwajalein, Majuro). Average to above-average rainfall is forecasted for the Yap, Guam, CNMI (Saipan) and average rainfall for Palau. Conversely, average-to-below normal precipitation is expected for American Samoa, while below-normal precipitation is expected in the Hawaiian Islands, according to the NOAA Pacific ENSO Applications Climate Center.


Information in the dashboard is grouped first by climate variable and/or impact and then by time frame. Click on any tab in the dashboard, it will expand to show an associated selection of panes. (Click again and it will collapse). Click on any figure in a pane to view a full-sized version, and click again to reduce it. Click on the “?” button to view the figure caption. Note that figures are automatically updated as often as the original providers post them on their respective websites (the update frequency is included in the caption). This means, the figures in the print version of the outlook may not be fully consistent with those found here. Click on the source URL to go to the site where the figure originated and find additional data and information.

Dashboard

Temperature & Precipitation

Recent/Current:

Latest Week of Global Rainfall

source: http://pmm.nasa.gov/TRMM/realtime-3hr-7day-rainfall


Current Total Precipitable Water

source: http://tropic.ssec.wisc.edu/real-time/mimic-tpw/wpac/main.html


NCEP Reanalysis Model - Air Temperature (Surface)

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


NCEP Reanalysis Model - Precipitable Water (Surface)

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


NCEP Reanalysis Model - Air Temperature Anomaly (Surface)

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


NCEP Reanalysis Model - Precipitable Water Anomaly (Surface)

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


NCEP Reanalysis Model - Relative Humidity (Surface)

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


NCEP Reanalysis Model - Sea Level Pressure

source: https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html


Tropical Outgoing Longwave Radiation Anomalies (OLRA) During the Last 30 Days

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


Time-Longitude Section of Anomalous OLR

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


ESRL 30-Day Average OLR Anomaly

source: https://www.esrl.noaa.gov/psd/map/clim/olr.shtml


GHCN-M Global Monthly Temperature Anomaly

source: https://www.ncdc.noaa.gov/temp-and-precip/ghcn-gridded-products/


Current Total Precipitable Water and Winds

source: http://www.nrlmry.navy.mil/


GPM Three-Month-Mean Satellite-Derived Precipitation Anomalies

source: https://pmm.nasa.gov/data-access/downloads/gpm


Forecast/Projections:

IRI Multi-Model Probability Forecast for Temperature

source: http://iridl.ldeo.columbia.edu/maproom/Global/Forecasts/Temperature.html


IRI Multi-Model Probability Forecast for Precipitation

source: http://iridl.ldeo.columbia.edu/maproom/Global/Forecasts/Precipitation.html


 
CFSv2 Three-Month-Mean Spatial Anomalies (Outlook) - Surface Air Temperature

source: http://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml


CFSv2 Three-Month-Mean Spatial Anomalies (Outlook) - Precipitation

source: http://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml


 
NMME Three-Month-Mean Spatial Anomalies (Outlook) - Surface Air Temperature

source: http://www.cpc.ncep.noaa.gov/products/NMME/


NMME Three-Month-Mean Spatial Anomalies (Outlook) - Precipitation

source: http://www.cpc.ncep.noaa.gov/products/NMME/


 

Drought & Stream Flow

Hawaii Drought Area Percentage

source: http://www.ncdc.noaa.gov/sotc/drought/


USGS Monthly Streamflow for Hawaii

source: http://waterwatch.usgs.gov/?m=real&r=hi


Tropical Cyclones & Storms

Tropical Wind Anomalies During the Last 30 Days

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


South Pacific Tropical Cyclone Tracks

source: http://weather.unisys.com/


 
NCEP Global Ocean Data Assimilation System (GODAS) - Tropical Cyclone Heat Potential

source: http://www.cpc.ncep.noaa.gov/products/GODAS/


West Pacific Tropical Cyclone Tracks

source: http://weather.unisys.com/


 
Global Tropical Hazards/Benefits Outlook

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/ghazards/


East Pacific Tropical Cyclone Tracks

source: http://weather.unisys.com/


Sea-Surface Temperatures, Ocean Conditions, & Impacts

Recent/Current:

SST Anomaly Animations - Tropical Pacific

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


SST Anomaly Animations - Equatorial Temperature Anomaly

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


Subsurface SST Anomaly - Tropical Pacific

source: http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/enso.shtml


NCEP Global Ocean Data Assimilation System (GODAS) Animations - SST Anomaly

source: http://www.cpc.ncep.noaa.gov/products/GODAS/


TAO/TRITON SST and Winds - Past 21 Days

source: http://www.pmel.noaa.gov/tao/jsdisplay/


Coral Reef Watch Products - Bleaching Alert Areas

source: http://coralreefwatch.noaa.gov/satellite/baa.php


Coral Reef Watch Products - Coral Bleaching Hotspots

source: http://coralreefwatch.noaa.gov/satellite/hotspot.php


Coral Reef Watch Products - Degree Heating Weeks

source: http://coralreefwatch.noaa.gov/satellite/dhw.php


OceanWatch - Central Pacific: Aqua MODIS Ocean Color

source: http://oceanwatch.pifsc.noaa.gov


OceanWatch - Central Pacific: Aquarius Sea-Surface Salinity

source: http://oceanwatch.pifsc.noaa.gov


OceanWatch - Central Pacific: GOES-POES Sea-Surface Temperature

source: http://oceanwatch.pifsc.noaa.gov


Forecast/Projections:

CFSv2 Three-Month-Mean Spatial Anomalies (Outlook) - Sea-Surface Temperature

source: http://www.cpc.ncep.noaa.gov/products/CFSv2/CFSv2seasonal.shtml


NMME Three-Month-Mean Spatial Anomalies (Outlook) - Sea-Surface Temperature

source: http://www.cpc.ncep.noaa.gov/products/NMME/


Probability of Coral Bleaching Thermal Stress

source: http://coralreefwatch.noaa.gov/satellite/bleachingoutlook_cfs/outlook_cfs.php


Probablisitic Coral Bleaching Thermal Stress Warning

source: http://coralreefwatch.noaa.gov/satellite/bleachingoutlook_cfs/outlook_cfs.php


Sea-Level & Waves

Recent/Current:

OSTM/Jason-3 Satellite Sea Level Residuals - 10 Day Averages

source: http://sealevel.jpl.nasa.gov/science/elninopdo/latestdata/


Forecast/Projections:

Pacific Region Sea-Surface Heights

source: https://www7320.nrlssc.navy.mil/GLBhycom1-12/


WaveWatch III - Pacific Region Wave Height and Direction

source: http://polar.ncep.noaa.gov/waves/viewer.shtml?-multi_1-pacific-


 
 

ENSO & Other Climate Indices

Regional Partners

Pacific ENSO Applications Climate Center:
http://www.weather.gov/peac/update
NOAA NWS Weather Forecast Office Honolulu :
http://www.prh.noaa.gov/pr/hnl/
NOAA NWS Weather Forecast Office Guam:
http://www.prh.noaa.gov/pr/guam/
NOAA National Centers for Environmental Information:
http://www.ncei.noaa.gov
NOAA NMFS Pacific Island Fisheries Science Center:
http://www.pifsc.noaa.gov/
NOAA OceanWatch - Central Pacific:
http://oceanwatch.pifsc.noaa.gov/
NOAA Coral Reef Watch:
http://coralreefwatch.noaa.gov/
USGS Pacific Islands Water Science Center:
http://hi.water.usgs.gov/
USGS Science Center - Pacific Coastal and Marine Science Center:
http://walrus.wr.usgs.gov/
University of Hawaii - Joint Institute of Marine and Atmospheric Research:
http://www.soest.hawaii.edu/jimar/
University of Guam - Water and Environmental Research Institute:
http://www.weriguam.org/
University of Hawaii Sea Level Center:
http://uhslc.soest.hawaii.edu/
University of Hawaii Asia-Pacific Data Research Center (APDRC)
http://apdrc.soest.hawaii.edu/

Previous Climate Impacts and Outlook