452
FXUS21 KWNC 171753
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT May 17 2026

SYNOPSIS: Mid-level low pressure is anticipated to shift eastward from the
Northeastern Pacific to the West Coast by the middle of week-2. Surface low
pressure is expected to develop ahead of this mid-level low pressure across the
central Contiguous U.S. (CONUS). This low pressure combined with enhanced moist
southerly flow from the Gulf increases the likelihood for heavy precipitation
across parts of the Southern Plains into the Southeastern U.S. from the end of
week-1 into Memorial Day weekend. Surface lows across the Interior West may
support episodes of high winds for parts of this region and the Great Plains.

HAZARDS

Moderate risk of heavy precipitation for the Southern Plains, Lower Mississippi
Valley, and Southeastern U.S., Mon-Wed, May 25-27.

Slight risk of heavy precipitation for portions of the Southern Plains, Lower
Mississippi and Tennessee Valleys, and Southeastern U.S., Mon-Fri, May 25-29.

Flooding possible for much of eastern and central Texas.

DETAILED SUMMARY

FOR WEDNESDAY MAY 20 - SUNDAY MAY 24:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR MONDAY MAY 25 - SUNDAY MAY 31: Multiple model ensemble means indicate
mid-level ridging across much of the country except for troughing across the
West Coast for the week-2 period. Above normal temperatures are favored across
much of the CONUS except for the West Coast, southern Four Corners region into
western Texas which is forecast to have near normal temperatures. The
Probabilistic Extremes Tools (PETs) indicate temperatures exceeding the 85th
percentile climatologically periodically across much of the interior portions
of the CONUS, however not reaching or exceeding hazardous criteria at this time.



Mid-level troughing with the trough axis centered across the West Coast is
predicted to continue from the end of week-1 into and through week-2. A series
of surface lows and trailing fronts are expected ahead of this trough over the
central CONUS. This pattern combined with enhanced southerly moist flow from
the Gulf increases the chances for heavy rainfall across parts of the
south-central and southeastern CONUS during Memorial Day weekend. A moderate
risk of heavy precipitation is designated for parts of the Southern Plains,
Lower Mississippi Valley, and Southeastern U.S., May 25-27, where the ECENS
(GEFS) indicate at least a 40% (30%) chance of 3-day rainfall exceeding one
inch, with uncalibrated guidance showing higher probabilities. A broader area
is highlighted across portions of the Southern Plains, Lower Mississippi and
Tennessee Valleys, and Southeastern U.S. with a slight risk (20-40% chance) of
heavy precipitation, May 25-29. Conditions may be conducive to thunderstorms
across the Great Plains and Mississippi Valley. Given the prevailing drought
conditions for many areas across the South, these rains may prove beneficial.
However, model solutions continue to depict a long-lived precipitation event
with multiple rounds of high intensity rainfall, and some watersheds in East
Texas are already beginning to rise in response to the large influx of surface
water. Day-7 QPF forecast from the Weather Prediction Center depicts
precipitation totals exceeding 3 inches across much of Texas, and with
continued heavy precipitation indicated well into week-2 there is increased
confidence for the potential of river flooding as a response to this event. A
flooding possible hazard is posted for much of East Texas and portions of the
Texas Hill Country, highlighting the highest potential for river and stream
flooding. However, urban and flash flooding is possible outside this area, and
caution should always be exercised when approaching floodwaters.



Ahead of the mid-level trough across the West Coast, surface lows are predicted
to form across the Interior West and in the lee of the Rockies, resulting in
enhanced surface winds over the Great Plains. There is insufficient signal from
model guidance to warrant issuing an associated hazard, however locally high
winds may be possible across the Great Plains as surface low pressure systems
develop along the Front Range.



In Alaska, river ice breakup season is now well underway. Many rivers are now
mostly ice-free but portions of the lower and middle Yukon as well as the
northern rivers have yet to melt out. Ice jam flooding can occur this time of
year with little or no notice as conditions on frozen rivers can change
quickly. Please check with the Alaska Pacific River Forecast Center for the
latest conditions and advisories.

FORECASTER: Danny Barandiaran

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