742
FXUS21 KWNC 071805
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT June 07 2026

SYNOPSIS: Strong mid-level high pressure near the West Coast increases the risk
of a multi-day heat wave for portions of the West during mid-June. A
slow-moving cold front leads to an elevated chance of locally heavy
precipitation across much of the eastern and south-central contiguous U.S.
(CONUS) from June 15 to 17. Later in the outlook period, a warming trend is
expected across the Southeast.

HAZARDS

Moderate risk of extreme heat for parts of the Pacific Northwest, Mon-Tue, Jun
15-16.

Slight risk of extreme heat for parts of the West, Mon-Thu, Jun 15-18.

Slight risk of extreme heat for parts of the Mid-Atlantic and Northeast, Mon,
Jun 15.

Slight risk of extreme heat for parts of the Southeast, Fri-Sun, Jun 19-21.

Slight risk of heavy precipitation for much of the eastern and south-central
CONUS, Mon-Wed, Jun 15-17.

Rapid onset drought possible for parts of northeastern Illinois and
northwestern Indiana.

DETAILED SUMMARY

FOR WEDNESDAY JUNE 10 - SUNDAY JUNE 14:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR MONDAY JUNE 15 - SUNDAY JUNE 21: The ECENS, GEFS, and CMCE remain in good
agreement and very consistent that a 500-hPa ridge strengthens later next week
over the northeastern Pacific. This mid-level ridge peaks in strength on day 7
(June 14), but the preferred ECENS and CMCE depict 500-hPa heights of 582 dm
persisting over the Pacific Northwest through June 16. These model solutions
have daily height departures of more than +120 meters in western parts of
Oregon and Washington, which signals an enhanced risk of a multi-day heat wave
for Portland and Seattle. Based on the good model agreement on this anomalously
strong 500-hPa ridge for June and a 40% (GEFS) to 60% (ECENS) chance of maximum
temperatures exceeding the 85th percentile according to the Probabilistic
Extreme Tools (PETs), a moderate risk of extreme heat continues for parts of
the Pacific Northwest on June 15 and 16. In addition, the National Blend of
Models shows near record or record highs of 95F in Portland and 87F at Seattle
on June 15. Since the NWS HeatRisk tool has less than a 40% chance of major
heat-related impacts and the PETs only have a 20 to 30% chance that maximum
temperatures reach 100 degrees F, the moderate risk of extreme heat is
discontinued for the Sacramento Valley of northern California. Based on the NWS
HeatRisk tool and PETs (20-40% chance of either major heat-related impacts or
maximum temperatures exceeding the 85th percentile), a broad slight risk of
extreme heat extends south through the Central Valley of California and Desert
Southwest. The slight risk of extreme heat ends on June 18 as the 500-hPa ridge
is forecast to weaken and shift away from the West Coast.



The potential heat wave across the Mid-Atlantic and Northeast later next week
is expected to time off at the beginning of week-2. However, the ECENS PET (20%
chance of maximum temperatures > 90F) supports the continuation of the slight
risk of extreme heat for the greater NYC area on June 15th. This slight risk
area extends south through the Mid-Atlantic where there is an elevated chance
that heat index values reach 105F.



The amplified 500-hPa trough upstream over the Midwest, a slow-moving/stalled
surface front, and anomalously high moisture content increase the chance of
locally heavy rainfall with any convection across much of the East extending
west to the Central and Southern Great Plains. The slight risk of heavy
precipitation, valid June 15-17, generally followed where the multi-model
ensemble means depict a slow-moving or stalled front and the PETs have 3-day
amounts exceeding the 85th percentile. Thunderstorms are likely to be capable
of producing more than 1 inch per 24 hours. A broad slight risk area is
necessary due to the uncertainty in convective rainfall at this time lead
during June. Given the anomalously high moisture, any slow-moving thunderstorm
could trigger flash flooding.



Beginning on June 17 or 18, the ECENS and GEFS favor a retrogression of the
longwave pattern which leads to a strengthening subtropical ridge over the
Southeast. The GEFS is most bullish with a warming trend and depicts maximum
temperatures above 95 degrees F from the Coastal Plain of the Carolinas and
Georgia south into the Florida Peninsula. Based on the calibrated heat index
tool (20-40% chance of heat index values to exceed the 90th percentile and
105F), a slight risk of extreme heat is posted for parts of the Southeast from
June 19 to 21.



30-day precipitation has averaged less than 50 percent of normal across much of
the Midwest. The U.S. Drought Monitor, valid June 2, depicts an expanding
coverage of abnormal dryness (D0) across this region and moderate drought (D1)
in northern Illinois and southern Wisconsin. Rapid onset drought (ROD) is
underway with this lack of adequate precipitation, warmer temperatures, and
increasing water demand at this time of year. The ROD hazard, currently
depicted in northeastern Illinois and northwestern Indiana, may be discontinued
on Monday as an increasingly wet pattern is forecast during the next two weeks.



In Alaska, river ice breakup season is ending and even the rivers across the
North Slope are beginning to open. 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: Brad Pugh

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