Nassau County, New York
Active alerts and forecasts are evaluated at the representative point shown below. Historical and climate evidence uses county-level data where available.
Representative point: Nassau County Census representative point, New York
- LAT
- 40.72961
- LON
- -73.58941
- ZONE
- America/New_York
- COUNTY_FIPS
- 36059
0–100 DECISION INDEX, NOT EVENT PROBABILITY
EVIDENCE QUALITY 67.5/100
No audience or operational context supplied.
What this assessment says.
Elevated available evidence for extreme heat and heat index.
2 intersecting official alerts. Forecast guidance available for supported hazards.High historical or climate indices for extreme heat and heat index, lightning, flash flooding.
Historical and climate indices describe planning exposure, not current conditions.Evidence layers are available across the 19 monitored hazards.
All registered sources responded. Not scored is different from zero.Active directives
Rip Current Statement issued August 26 at 2:59PM EDT until August 27 at 9:00PM EDT by NWS Upton NY
Kings (Brooklyn); Southwest Suffolk; Southeast Suffolk; Southern Queens; Southern Nassau
OFFICIAL INSTRUCTION, VERBATIMIf you enter the surf zone, always have a flotation device with you and swim near a lifeguard. If caught in a rip current, relax and float, and do not swim against the current. If able, swim in a direction following the shoreline. If unable to escape, face the shore and yell or wave for help.SOURCE: NWS Upton NY
Flood Watch issued August 26 at 2:27PM EDT until August 27 at 11:00PM EDT by NWS Upton NY
Northern Fairfield; Southern Fairfield; Western Passaic; Eastern Passaic; Hudson; Western Bergen; Eastern Bergen; Western Essex; Eastern Essex; Western Union; Eastern Union; Orange; Putnam; Rockland; Northern Westchester; Southern Westchester; New York (Manhattan); Bronx; Richmond (Staten Is.); Kings (Brooklyn); Northern Queens; Northern Nassau; Southern Queens; Southern Nassau
OFFICIAL INSTRUCTION, VERBATIMYou should monitor later forecasts and be alert for possible Flood Warnings. Those living in areas prone to flooding should be prepared to take action should flooding develop.SOURCE: NWS Upton NY
Risk by hazard
Weights: active 40% · forecast 30% · history 20% · climate 10%
| Hazard | Assessment | Current and 14-day | Long-term evidence | Evidence |
|---|---|---|---|---|
| Extreme heat and heat indexCURRENT / NEAR-TERM | 40/100Moderate | ACTIVENo matching alert14-DAY50/100 | HISTORYNot scoredCLIMATE86.2/100 | 3 OF 4LAYERS AVAILABLEQUALITY 67.5/100 |
| Flash floodingHIGH LONG-TERM | 32.3/100Low | ACTIVENo matching alert14-DAY25/100 | HISTORY97.9/100CLIMATE51.7/100 | 4 OF 4LAYERS AVAILABLEQUALITY 84.5/100 |
| LightningHIGH LONG-TERM | 21.3/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORY98.9/100CLIMATENot scored | 3 OF 4LAYERS AVAILABLEQUALITY 77.5/100 |
| Urban flooding | 19.7/100Low | ACTIVE17.5/10014-DAY25/100 | HISTORYNot scoredCLIMATE51.7/100 | 3 OF 4LAYERS AVAILABLEQUALITY 67.5/100 |
| Heavy rain and atmospheric rivers | 17.7/100Low | ACTIVENo matching alert14-DAY21.7/100 | HISTORY30.2/100CLIMATE51.7/100 | 4 OF 4LAYERS AVAILABLEQUALITY 84.5/100 |
| River flooding | 18/100Low | ACTIVE17.5/10014-DAYNot scored | HISTORY29.1/100CLIMATE51.7/100 | 3 OF 4LAYERS AVAILABLEQUALITY 62.0/100 |
| Severe thunderstorms | 16.8/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORY76.7/100CLIMATENot scored | 3 OF 4LAYERS AVAILABLEQUALITY 77.5/100 |
| Extreme cold and wind chill | 2.9/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORYNot scoredCLIMATE13.8/100 | 3 OF 4LAYERS AVAILABLEQUALITY 67.5/100 |
| Blizzards | 1.5/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORYNot scoredCLIMATENot scored | 2 OF 4LAYERS AVAILABLEQUALITY 60.5/100 |
| Ice storms and freezing rain | 1.5/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORYNot scoredCLIMATENot scored | 2 OF 4LAYERS AVAILABLEQUALITY 60.5/100 |
| Winter storms and heavy snow | 1.5/100Low | ACTIVENo matching alert14-DAY5/100 | HISTORYNot scoredCLIMATENot scored | 2 OF 4LAYERS AVAILABLEQUALITY 60.5/100 |
| Wildfires | 6.7/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATE67.3/100 | 2 OF 4LAYERS AVAILABLEQUALITY 45.0/100 |
| Coastal flooding | 5.2/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATE51.7/100 | 2 OF 4LAYERS AVAILABLEQUALITY 45.0/100 |
| Drought | 4.8/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATE48.3/100 | 2 OF 4LAYERS AVAILABLEQUALITY 45.0/100 |
| Hail | 5.9/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORY29.3/100CLIMATENot scored | 2 OF 4LAYERS AVAILABLEQUALITY 55.0/100 |
| Tornadoes | 5.2/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORY25.8/100CLIMATENot scored | 2 OF 4LAYERS AVAILABLEQUALITY 55.0/100 |
| Hurricanes and tropical storms | 0/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATENot scored | 1 OF 4LAYERS AVAILABLEQUALITY 38.0/100 |
| Storm surge | 0/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATENot scored | 1 OF 4LAYERS AVAILABLEQUALITY 38.0/100 |
| Wildfire smoke and degraded air quality | 0/100Low | ACTIVENo matching alert14-DAYNot scored | HISTORYNot scoredCLIMATENot scored | 1 OF 4LAYERS AVAILABLEQUALITY 38.0/100 |
Component evidence
Extreme heat and heat index
40/100 · Moderate3 of 4 layers available · evidence quality 67.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 50/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 86.2/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
43.6/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Flash flooding
32.3/100 · Low4 of 4 layers available · evidence quality 84.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 25/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- 97.9/10075 NOAA county reports in 2016–2025; national midrank percentile 97.88. Reports are not unique storms.
- CLIMATE
- 51.7/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Lightning
21.3/100 · Low3 of 4 layers available · evidence quality 77.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- 98.9/10012 NOAA county reports in 2016–2025; national midrank percentile 98.89. Reports are not unique storms.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
31.3/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Urban flooding
19.7/100 · Low3 of 4 layers available · evidence quality 67.5/100
- ACTIVE
- 17.5/1001 intersecting official alert.
- FORECAST
- 25/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 51.7/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
39.7/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Heavy rain and atmospheric rivers
17.7/100 · Low4 of 4 layers available · evidence quality 84.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 21.7/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- 30.2/1000 NOAA county reports in 2016–2025; national midrank percentile 30.15. Reports are not unique storms.
- CLIMATE
- 51.7/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
River flooding
18/100 · Low3 of 4 layers available · evidence quality 62.0/100
- ACTIVE
- 17.5/1001 intersecting official alert.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- 29.1/1001 NOAA county report in 2016–2025; national midrank percentile 29.06. Reports are not unique storms.
- CLIMATE
- 51.7/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Severe thunderstorms
16.8/100 · Low3 of 4 layers available · evidence quality 77.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- 76.7/10075 NOAA county reports in 2016–2025; national midrank percentile 76.65. Reports are not unique storms.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
26.8/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Extreme cold and wind chill
2.9/100 · Low3 of 4 layers available · evidence quality 67.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 13.8/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
22.9/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Blizzards
1.5/100 · Low2 of 4 layers available · evidence quality 60.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
31.5/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Ice storms and freezing rain
1.5/100 · Low2 of 4 layers available · evidence quality 60.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
31.5/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Winter storms and heavy snow
1.5/100 · Low2 of 4 layers available · evidence quality 60.5/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- 5/100Derived from the 14-day daily model series using published INSIT3 thresholds.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
31.5/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Wildfires
6.7/100 · Low2 of 4 layers available · evidence quality 45.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 67.3/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Coastal flooding
5.2/100 · Low2 of 4 layers available · evidence quality 45.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 51.7/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Drought
4.8/100 · Low2 of 4 layers available · evidence quality 45.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- 48.3/100Recent 10-year county mean ranked against the NOAA 1991–2020 baseline series.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Hail
5.9/100 · Low2 of 4 layers available · evidence quality 55.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- 29.3/1008 NOAA county reports in 2016–2025; national midrank percentile 29.31. Reports are not unique storms.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Tornadoes
5.2/100 · Low2 of 4 layers available · evidence quality 55.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- 25.8/1001 NOAA county report in 2016–2025; national midrank percentile 25.75. Reports are not unique storms.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Hurricanes and tropical storms
0/100 · Low1 of 4 layers available · evidence quality 38.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Storm surge
0/100 · Low1 of 4 layers available · evidence quality 38.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Wildfire smoke and degraded air quality
0/100 · Low1 of 4 layers available · evidence quality 38.0/100
- ACTIVE
- 0/100No matching active NWS alert at retrieval time.
- FORECAST
- Not scoredNo uniform location-level forecast product is available for this hazard.
- HISTORY
- Not scoredThis hazard is not uniformly county-coded in NOAA Storm Events; it remains unsupported rather than being forced into a county score.
- CLIMATE
- Not scoredNo defensible county climate proxy is available for this event hazard.
Technical missing-data bound
80/100 is the mathematical worst case if missing layers were maximally adverse. It is not an expected range, probability, or forecast.
Recommendations.
- 01Monitor linked issuing agencies and compare source issue, validity, and expiration times before acting.
- 02Use the highest active or forecast hazard as the planning driver; do not average away a severe local threat.
- 03Prioritize preparedness for extreme heat and heat index based on the currently confirmed score floor.
These recommendations never create, paraphrase, or override evacuation or shelter orders.
Sources
- AVAILABLE
Active alerts
NOAA / National Weather Service · retrieved 2026-08-26T19:50:46.673Z
CAP-compatible active alerts intersecting the evaluated point.
https://api.weather.gov/alerts/active?point=40.729612,-73.589414 - AVAILABLE
14-day forecast
Open-Meteo using NOAA and other national weather models · retrieved 2026-08-26T15:17:50.988Z
Daily cached model forecast retrieved 2026-08-26T15:17:50.988Z. Days 8–14 are model guidance, not deterministic NWS hazard forecasts.
https://api.open-meteo.com/v1/forecast?latitude=40.729612&longitude=-73.589414&daily=temperature_2m_max,temperature_2m_min,apparent_temperature_max,apparent_temperature_min,precipitation_sum,precipitation_probability_max,snowfall_sum,wind_gusts_10m_max,weather_code&temperature_unit=fahrenheit&wind_speed_unit=mph&precipitation_unit=inch&forecast_days=14&timezone=auto - AVAILABLE
National Risk Index supplemental baseline
FEMA · retrieved 2026-08-26T19:50:46.673Z
County-level March 2023 relative risk. Displayed as context; not substituted for the requested rolling 10-year component.
https://services.arcgis.com/HdtZMT2FmI4wPzTM/ArcGIS/rest/services/FEMA_National_Risk_Index/FeatureServer/0/query?geometry=-73.589414%2C40.729612&geometryType=esriGeometryPoint&inSR=4326&spatialRel=esriSpatialRelIntersects&outFields=STATE%2CCOUNTY%2CSTCOFIPS%2CNRI_VER%2CRISK_SCORE%2CRISK_RATNG%2CHWAV_RISKS%2CCWAV_RISKS%2CDRGT_RISKS%2CWFIR_RISKS%2CHRCN_RISKS%2CTRND_RISKS%2CHAIL_RISKS%2CLTNG_RISKS%2CRFLD_RISKS%2CWNTW_RISKS%2CISTM_RISKS&returnGeometry=false&f=json - AVAILABLE
2016–2025 county event history
NOAA / NCEI Storm Events · retrieved 2026-08-26T12:38:24Z
One NOAA Storm Events detail record; counts are reports, not unique storms. Seven hazards have complete county-coded coverage; unsupported hazard/geography combinations remain null.
https://www.ncei.noaa.gov/pub/data/swdi/stormevents/csvfiles/ - AVAILABLE
County temperature normal and series
NOAA / NCEI Climate at a Glance · retrieved 2026-08-26T19:50:46.673Z
1991–2020 normal compared with the latest complete rolling 10-year county series.
https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/time-series/NY-059/tavg/12/12/1991-2025.json?base_prd=true&begbaseyear=1991&endbaseyear=2020 - AVAILABLE
County precipitation normal and series
NOAA / NCEI Climate at a Glance · retrieved 2026-08-26T19:50:46.673Z
1991–2020 normal compared with the latest complete rolling 10-year county series.
https://www.ncei.noaa.gov/access/monitoring/climate-at-a-glance/county/time-series/NY-059/pcp/12/12/1991-2025.json?base_prd=true&begbaseyear=1991&endbaseyear=2020
- The primary score is a confirmed 0–100 decision index, not an event probability. A technical worst-case bound remains available in component evidence when required data is missing, but it is not an expected range or forecast.
- Source outages and unsupported hazard layers are shown as unavailable or not scored. Missing evidence is never treated as zero.
- Days 8–14 use freely available model guidance. NOAA CPC outlooks do not provide deterministic location-level forecasts for every hazard.
- FEMA National Risk Index values use hazard-specific source windows and are supplemental. They are never labeled as the requested rolling 10-year history.
- Climate trend scores are county-level derived comparisons, not event forecasts. Tornado, hail, hurricane, surge, smoke, lightning-strike, blizzard, and ice-event projections remain unscored where no defensible source exists.
- Low or unscored risk does not mean safe. Follow current instructions from the issuing authority.