672
FXUS21 KWNC 271755
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT May 27 2026

SYNOPSIS: Mid-level high pressure is predicted to linger across the West Coast
and Southwest from the end of week-1 into the onset of week-2, continuing the
risk of extreme heat for the central valley of California and parts of the
Desert Southwest for June 4. As this mid-level high pressure shifts eastward to
across the central contiguous U.S. (CONUS), so will the increased likelihood
for extreme heat. A slight risk of extreme heat is designated for the Midwest
including the Northern and Central Plains towards the latter part of week-2. A
stationary front is expected to continue from the end of week-1 into the start
of week-2 across the Gulf, which could result in heavy precipitation across
parts of the Southeast. High winds are possible across parts of the California
Coast from beginning to mid week-2.

HAZARDS

Slight risk of extreme heat for the central Valley of California and parts of
the Desert Southwest, Thu, June 4.

Slight risk of extreme heat for portions of the Northern and Central Plains,
Upper and Middle Mississippi, and Ohio Valleys, and western Great Lakes region,
Sun-Wed, June 7-10.

Slight risk of heavy precipitation for parts of the Southeast, Thu-Fri, June
4-5.

Slight risk of high winds for parts of the California coast, Thu-Mon, June 4-8.

DETAILED SUMMARY

FOR SATURDAY MAY 30 - WEDNESDAY JUNE 03:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR THURSDAY JUNE 04 - WEDNESDAY JUNE 10: There is good agreement among
multiple models indicating mid-level ridging lingering across the West Coast
and Southwest from the end of week-1 into the onset of week-2. This favors
continuance of the slight risk of extreme heat  for the central Valley of
California and parts of the Desert Southwest, June 4. The Probabilistic
Extremes Tools (PETs) indicate at least a 20 to 30% chance of temperatures
exceeding the 85th percentile climatologically and 95-100  deg F. The Weather
Prediction Centers (WPC) experimental Probabilistic HeatRisk tool shows
enhanced potential for major or higher heat risk levels.



The aforementioned ridge is anticipated to shift eastward early in the period
around day 9 (June 5), stretching across much of the central CONUS as a trough
develops over the West Coast. This pattern is predicted to result in increasing
temperatures across the region with the greatest chances for above-normal
temperatures during week-2 forecast for the north-central CONUS. A slight risk
of extreme heat is highlighted across portions of the Northern and Central
Plains, Upper and Middle Mississippi, and Ohio Valleys, and western Great Lakes
region, June 7-10. Multiple PETs indicate at least a 20% chance of temperatures
exceeding the 85th percentile and 90 deg F (85 deg F across more northern
regions). Southerly enhanced moist flow is possible as surface high pressure
forms across the East, resulting in higher relative humidity which could result
in higher heat index temperatures across the risk area. This increased
potential for extreme heat in this hazard area is supported by various heat
risk tools as well.



A stationary front draped across the Gulf Coast and northern Florida is
predicted to linger from the end of week-1 into the beginning of week-2,
continuing the increased possibility of heavy precipitation across the region.
A slight risk of heavy precipitation is designated for areas as far north as
southern Alabama and Georgia based on where PETs show at least a 20% chance of
3-day rainfall (at the beginning of week-2) exceed the 85th percentile and one
inch, with the first two days of the period being the focus of the heavy
rainfall (June 4-5). This is further supported by uncalibrated GEFS and ECENS
guidance, with the ECENS indicating more widespread areas reaching these
thresholds compared to the GEFS. The moderate risk is discontinued due to
increased uncertainty of where the heaviest rainfall will be and the greatest
totals occurring at the end of week-1. Given the anomalous low to mid-level
moisture and weak steering flow, any slow-moving thunderstorms would increase
the risk of flash flooding. The transition from a dry La Nina pattern to a
wetter regime would bring drought relief to the Southeast. According to the
U.S. Drought Monitor valid May 19, three-quarters of Florida is designated with
extreme (D3) to exceptional (D4) drought. Despite current dry conditions,
anticipated antecedent heavy rainfall may initiate flood conditions.



A tight pressure gradient may set up across parts of coastal California due to
a thermal low developing across Baja California and the Desert Southwest due to
intense solar heating and adjacent surface high pressure off the shore of
coastal California. This set up supports a slight risk of episodic high winds
for parts of coastal California June 4-8. The PETs indicate at least a 20%
chance of wind speeds exceeding the 85th percentile and 25 mph, further
supported by uncalibrated guidance showing increased potential for wind gusts
exceeding 34 mph.



In Alaska, river ice breakup season is ending, but many rivers north of the
Brooks Range remain icebound. 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: Melissa Ou

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