El Niño update, September 27: what to know

What’s happening

• The NWS river forecast center in Sacramento says: “Dry conditions across the region today as it sits under a general troughing pattern.” Source: CNRFC Hydrometeorological Discussion (opens in a new tab)
• The Storm Prediction Center says: “Additionally, a subtle vorticity maxima is forecast to lift quickly from near the southern California coast toward the northern Plains.” Source: SPC Day 1 Convective Outlook (opens in a new tab)
• The U.S. Drought Monitor: “CA drought coverage, week of 2026-09-22: 30.24% none, D0 69.76%, D1 23.26%, D2 0.00%, D3 0.00%, D4 0.00%.” Source: U.S. Drought Monitor — CA (opens in a new tab)

What to watch for

No items for this region in this post.

Active NWS alerts: none in effect when this was generated.

What’s happening

• Active NWS alert: Beach Hazards Statement, in effect until 5:00 AM PDT (NWS San Diego CA), for parts of San Diego County Coastal Areas and Orange County Coastal. Source: NWS active alerts — CA (opens in a new tab)
• Active NWS alert: Beach Hazards Statement, in effect until 4:00 PM PDT (NWS Los Angeles/Oxnard CA), for parts of Santa Barbara County Southwestern Coast and Santa Barbara County Southeastern Coast. Source: NWS active alerts — CA (opens in a new tab)
• Active NWS alert: Coastal Flood Advisory, in effect until 5:00 PM PDT (NWS San Diego CA), for parts of San Diego County Coastal Areas and Orange County Coastal. Source: NWS active alerts — CA (opens in a new tab)

What to watch for

No items for this region in this post.

Active NWS alerts: Beach Hazards Statement: 3 (CA) · Coastal Flood Advisory: 2 (CA) · High Surf Advisory: 1 (CA)

What’s happening

• Active NWS alert: Flood Watch, in effect until 12:00 AM MDT (NWS Tucson AZ), for parts of Western Pima County Including Ajo/Organ Pipe Cactus National Monument, Tohono O’odham Nation including Sells and Upper Santa Cruz River and Altar Valleys including Nogales. Source: NWS active alerts — AZ (opens in a new tab)
• Active NWS alert: Flood Watch, in effect until 12:00 AM MDT (NWS Las Vegas NV), for parts of Northwest Plateau, Hualapai Mountains and Northwest Deserts. Source: NWS active alerts — AZ (opens in a new tab)
• Active NWS alert: Flood Watch, in effect until 12:00 AM MDT (NWS Flagstaff AZ), for parts of Kaibab Plateau, Marble and Glen Canyons and Grand Canyon Country. Source: NWS active alerts — AZ (opens in a new tab)

What to watch for

• The Weather Prediction Center says: “Excessive rainfall/flooding threats over the Southwest/Southern Rockies states through midweek will focus over the South-central U.S. and with Gulf coastal frontal genesis mid-later week into next weekend.” Source: WPC Extended Forecast Discussion (opens in a new tab)

Active NWS alerts: Flood Watch: 7 (AZ, NM, UT) · Hydrologic Outlook: 1 (UT)

What’s happening

• Active NWS alert: Flash Flood Warning, in effect until 3:00 AM CDT (NWS Midland/Odessa TX), for parts of Glasscock, TX. Source: NWS active alerts — TX (opens in a new tab)
• Active NWS alert: Flood Watch, in effect until 7:00 AM CDT (NWS El Paso Tx/Santa Teresa NM), for parts of Upper Gila River Valley, Southern Gila Foothills/Mimbres Valley and Southwest Desert/Lower Gila River Valley. Source: NWS active alerts — TX (opens in a new tab)
• Active NWS alert: Air Quality Alert (NWS Houston/Galveston TX), for parts of Inland Harris, Inland Brazoria and Inland Galveston. Source: NWS active alerts — TX (opens in a new tab)

What to watch for

• NOAA’s Climate Prediction Center says: “Downstream troughing is forecast over the northeastern CONUS with cyclonic flow extending southward to the Gulf Coast.” Source: CPC 6-10 / 8-14 Day Outlook Discussion (opens in a new tab)

Active NWS alerts: Air Quality Alert: 2 (TX) · Flash Flood Warning: 1 (TX) · Flood Watch: 1 (TX)

What’s happening

• Active NWS alert: Coastal Flood Warning, in effect until 5:00 PM EDT (NWS Key West FL), for parts of Monroe Upper Keys. Source: NWS active alerts — FL (opens in a new tab)
• Active NWS alert: Coastal Flood Warning, in effect until 12:00 PM EDT (NWS Wakefield VA), for parts of Eastern Currituck. Source: NWS active alerts — NC (opens in a new tab)
• Active NWS alert: Flood Warning (NWS Melbourne FL), for parts of Lake, FL and Volusia, FL. Source: NWS active alerts — FL (opens in a new tab)

What to watch for

• NOAA’s Climate Prediction Center says: “Slight risk of heavy precipitation for the Florida Peninsula, Sun-Sat, Oct 4-10.” Source: CPC U.S. Hazards Outlook (opens in a new tab)
• NOAA’s Climate Prediction Center says: “Prior to the beginning of this period, the NHC is highlighting the potential for Polo (or its remnants) to recurve and approach the south-central CONUS. This evolution would increase chances of an active period for portions of the…” Source: CPC 6-10 / 8-14 Day Outlook Discussion (opens in a new tab)

Active NWS alerts: Coastal Flood Advisory: 11 (FL, GA, SC, NC) · Rip Current Statement: 6 (FL, GA) · Beach Hazards Statement: 3 (NC) · Coastal Flood Statement: 3 (FL) · Coastal Flood Warning: 2 (FL, NC) · High Surf Advisory: 2 (NC) · Flood Warning: 1 (FL)