071 

FXUS21 KWNC 201800

PMDTHR

US Hazards Outlook

NWS Climate Prediction Center College Park MD

300 PM EDT May 20 2026



SYNOPSIS: A continuation of mid-level cyclonic flow over the southwestern 

contiguous U.S. (CONUS) as well as enhanced low-level moist, southerly flow 

from the Gulf of America from week-1 into early week-2, supports a lingering 

risk for heavy precipitation from the Southern Plains to the Southeast. The 

duration of above-normal precipitation coupled with the multiple rounds of 

potentially heavy rainfall may lead to flooding over portions of the Southern 

Plains and Lower Mississippi Valley.  Mid-level low pressure favored over the 

western CONUS supports an increased risk of episodes of high winds across the 

Interior West, High Plains, and portions of the West Coast. Mid-level high 

pressure favored over Canada is expected to bring well above-normal 

temperatures for the north-central CONUS, though actual temperatures are 

expected to remain below heat thresholds. 



HAZARDS



Slight risk of heavy precipitation for portions of the Southern Plains, Lower 

and Middle Mississippi, Tennessee, and Ohio Valleys, Southeast, Southern 

Appalachians, and lower Mid-Atlantic, Thu-Sat, May 28-30.



Flooding possible for much of eastern Texas, portions of Oklahoma, Arkansas, 

Louisiana, and Mississippi.



Slight risk of high winds for much of the Interior West and High Plains, 

Thu-Sat, May 28-30.



Slight risk of high winds for portions of coastal California and Oregon, 

Thu-Sat, May 28-30. 



DETAILED SUMMARY



FOR SATURDAY MAY 23 - WEDNESDAY MAY 27: 

https://www.wpc.ncep.noaa.gov/threats/threats.php



FOR THURSDAY MAY 28 - WEDNESDAY JUNE 03: Dynamical model 500-hPa height 

forecasts from the GEFS and ECMWF ensembles have come into much better 

agreement today, following a few days where guidance had been struggling to 

resolve a number of key mid-level features across North America. Early in 

week-2, both the GEFS and ECMWF favor an amplifying ridge center over the 

Hudson Bay, with a broad coverage of positive height departures over the 

north-central and northeastern CONUS.  Weaknesses in the height pattern look to 

persist across the southern tier of the U.S., characterized by broad cyclonic 

flow conducive for continued enhanced precipitation across the Gulf states next 

week. Upstream, the GEFS has become better aligned with the ECMWF and Canadian 

ensemble, and now features anomalous troughing digging into the Interior West 

to promote cooler and more unsettled weather later next week. Over time, both 

the GEFS and ECMWF ensembles are starting to show signs of the ridging over 

Canada to retrograde, with rising heights favored over the northwestern CONUS. 

If realized, this pattern transition might promote the expansion of 

unseasonable warmth out West by the start of June. 







Associated with cyclonic mid-level flow across the southern tier and return 

flow from the Gulf at the surface next week, there is a lingering threat of 

heavy precipitation heading into the start of the period. The ECMWF continues 

to remain the most bullish with this risk, with its uncalibrated tool 

continuing to indicate 30-50% chances for 3-day amounts exceeding an inch, and 

its Probabilistic Extreme Tool (PET) depicting similar chances for these 

amounts exceeding the 85th climatological percentile. However, drier conditions 

are favored in the GEFS, GEFS-AI, and Canadian guidance due to the weakening of 

the mean surface high over western Atlantic resulting in weaker return flow. 

Therefore, the moderate risk of heavy precipitation is discontinued, but a 

corresponding slight risk area remains posted where both the GEFS and ECMWF 

PETs maintain at least 20% chances of 3-day amounts exceeding the 85th 

percentile and 1 inch. Relative to yesterday, coverage for the slight risk area 

has been slightly adjusted and is extended an additional day (now valid through 

May 30) based on an uptick in wet signals among the tools towards the middle of 

week-2.     







The risk of heavy precipitation highlighted early in week-2 follows an active 

precipitation regime over the south-central CONUS during week-1. While this 

pattern may prove to be beneficial in bringing improvement to prevailing 

drought conditions, the duration of above-normal precipitation coupled with 

multiple rounds of potentially heavy rainfall may trigger flooding, as some 

watersheds are already beginning to rise in response to the large influx of 

surface water. Week-1 QPF forecasts from the Weather Prediction Center depict 

precipitation totals exceeding 3-5 inches from southeastern Texas northeastward 

into portions of Arkansas and Louisiana, and any continued heavy precipitation 

into week-2 supports the potential of river flooding. A flooding possible 

hazard is expanded in the updated outlook to include portions of Oklahoma, 

Arkansas, and Mississippi, highlighting the highest potential for river and 

stream flooding. 







Given the better agreement between the ECMWF and GEFS in regards to anomalous 

troughing over the Interior West, a slight risk of high winds is posted at the 

base and ahead of the mean mid-level trough favored early in week-2, where the 

uncalibrated ECMWF shows increased chances for wind gusts exceeding 34kts 

(~40mph) over many parts of the Rockies and High Plains. The combination of 

above-normal temperatures, antecedent dryness and periods of high winds is 

supportive of an elevated wildfire risk within the slight risk area. In 

addition, a second slight risk area for high winds is also posted over portions 

of coastal California and southern Oregon, based on strengthening gradients 

favored in the GEFS and ECMWF surface pressure fields and increased wind speed 

signals in both the GEFS and ECMWF PETs.  Both wind hazards remain valid 

through May 30 before the troughing aloft deamplifies.  







For temperatures, there is better model and tool agreement favoring the 

strongest positive temperature departures over much of north-central and 

northeastern CONUS in proximity to the amplified ridge center over the Hudson 

Bay throughout the period. Compared to the GEFS, there continues to be stronger 

warm signals in the ECMWF PET due to the stronger ridging, but regardless of 

these differences in magnitude among the PETS, there is little to no signal in 

the tools for actual temperatures reaching above 95 deg F to drive higher heat 

index values over this part of the country, precluding any corresponding heat 

hazards. This is supported in the NWS probabilistic National Blend of Models 

(NBM) Heat Risk guidance, which depicts modest chances for temperatures 

exceeding red level thresholds over the Northern Plains, Upper Mississippi 

Valley, Great Lakes and Ohio Valley. Even with the low risk for extreme heat 

conditions, the Northern Plains continues to be monitored for a potential Rapid 

Onset Drought (ROD) given the prevailing unseasonable late spring warmth 

expected combined with antecedent dryness. Soil moisture percentiles are 

running quite low from eastern Montana to North Dakota, as any continued lack 

of rainfall to worsen dryness, abetted by elevated evapotranspiration rates 

would support a ROD risk. However, there continues to be a number of 

precipitation tools that favor a tilt towards above-normal precipitation during 

week-2 to allay this risk at this time.  







In Alaska, river ice breakup season is now well underway. Parts of the middle 

or lower Yukon are currently partially open, but are expected to be clear by 

the week-2 period. However, the threat of ice jam flooding would most likely be 

along rivers north of the Arctic Circle as they are currently mostly ice. River 

breakup flooding can occur with little or no notice as conditions on frozen 

rivers can change quickly, so please check with the Alaska Pacific River 

Forecast Center for the latest conditions and advisories. 



FORECASTER: Nick Novella 



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