Valid Saturday September 12, 2026 to Friday September 18, 2026
US Hazards Outlook NWS Climate Prediction Center College Park MD 300 PM
EDT September 04 2026
Synopsis: Model ensembles continue to favor
chances of above normal temperatures and a chance of extreme heat into week-2
tied to anomalous mid-level high pressure across southern and central
Contiguous U.S. (CONUS). A potential surge of moisture from the Gulf of
California may result in heavy precipitation over portions of the Desert
Southwest and Great Basin. Antecedent dryness, combined with little
precipitation favored over the next two weeks supports a Rapid Onset Drought
(ROD) risk for portions of the Central and Southern Plains, Lower and Middle
Mississippi, Ohio and Tennessee Valleys.
Hazards
Slight
risk of extreme heat across much of the Great Plains, Middle and Lower
Mississippi, Ohio, and Tennessee Valleys, Sat, Sep 12.
Slight risk of heavy precipitation for portions of the Desert Southwest and
Great Basin, Sat-Mon, Sep 12-14.
Rapid Onset Drought (ROD) risk for portions of the Central and Southern
Plains and the Middle and Lower Mississippi, Tennessee, and Ohio Valleys.
For Saturday September 12 -
Friday September 18: Dynamical model guidance remains in agreement
regarding chances for subtropical ridging persisting over the south-central
U.S. into week-2, with the 0z ECMWF, GEFS, and Canadian ensembles depicting
positive 500-hPa height anomalies early in week-2 across the central and
eastern CONUS. This lends itself to continued elevated chances for above normal
temperatures during much of the week-2 period. The Probabilistic Extremes Tools
(PETs) continue to show a greater than 20% chance for maximum temperatures to
exceed the 95th climatological percentile for day 8 across much of the central
CONUS. Uncalibrated apparent temperatures forecast apparent temperatures slowly
declining from week-1 into week-2 across portions of the Central and Southern
Plains. By day 9, these chances are significantly reduced for extreme heat
across the south-central and southeastern CONUS. Therefore, a slight risk of
extreme heat remains posted for only Sep 12 for these regions.
Model ensembles indicate a mid-level trough off the West Coast early in
week-2. This may combine with enhanced moisture from the Gulf of California due
to tropical activity over the Eastern Pacific to generate heavy precipitation
over the North American monsoon region. Uncalibrated probabilities from the
GEFS and ECMWF both indicate at least a 20% chance of 3-day precipitation to
exceed half an inch over the region early in the forecast period. Deterministic
guidance in particular continues to show chances for heavy precipitation into
the southwestern CONUS early in the week-2 period. Therefore, a slight risk of
heavy precipitation is posted for Sep 12-14. This region is prone to flash
flooding and caution should be exercised near canyons and creek beds, and
additional rainfall may hamper recovery efforts from recent flooding in the
Grand Canyon.
A Rapid Onset Drought (ROD) risk remains designated for parts of the
Southern Plains and Lower Mississippi Valley and adjacent portions of the
Central Plains, Ohio, Tennessee and Middle Mississippi Valleys, and Southeast
U.S. An area of western Kentucky and Tennessee was added to the Rapid Onset
Drought risk today; as with other areas of the ROD risk, this area has seen 20%
to 40% of normal precipitation and deficits of 1 to 2 inches over the past 30
days. Near to below normal precipitation and above normal temperatures remain
forecast for this region over the next two weeks increasing evapotranspiration
rates into the middle of September.
Forecaster: Ryan Bolt
$$
Please consult local NWS Forecast Offices for short range forecasts and region-specific information.
www.nws.noaa.gov
