342
FXUS21 KWNC 311823
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT May 31 2026

SYNOPSIS: Increased potential of extreme heat continues across parts of the
central and east-central contiguous U.S. (CONUS) associated with strong
mid-level high pressure centered over the Upper Mississippi Valley. Increased
moisture associated with a potential tropical wave may result in heavy
precipitation for the Florida Peninsula through the middle of week-2.

HAZARDS

Slight risk of extreme heat for portions of the Northern and Central Plains,
Upper and Middle Mississippi and Ohio Valleys, and Great Lakes region,
Mon-Thur, June 8-11.

Slight risk of heavy precipitation for the Florida peninsula, Mon-Fri, June
8-12.

Possible Rapid Onset Drought for parts of the Upper and Middle Mississippi
Valley and Great Lakes region.

DETAILED SUMMARY

FOR WEDNESDAY JUNE 03 - SUNDAY JUNE 07:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR MONDAY JUNE 08 - SUNDAY JUNE 14: Multiple model ensemble solutions for
500-hPa height anomalies depict amplified ridging over the Upper Mississippi
Valley at the outset of week-2, which is then favored to weaken somewhat and
widen to eventually span most of the U.S.-Canadian border by the end of week-2.
This is likely to bring above-normal temperatures across much of the CONUS,
particularly for the Upper Midwest, under the axis of the ridge. The
Probabilistic Extremes Tools (PETs) from both the ECMWF and GEFS indicate at
least a 20% chance of maximum temperatures to exceed the 85th climatological
percentile and at least 90F from the Northern Plains eastward into the Ohio
Valley through at least the middle of the forecast period. The GEFS indicates a
long-lived event, meeting the above criteria for all of week-2, while the ECMWF
has a weaker signal in the second half of week-2. Going with the best model
consensus, a slight risk of extreme heat remains posted for portions of the
Northern and Central Plains, Upper and Middle Mississippi and Ohio Valleys, and
Great Lakes region, valid Jun 8-11.



Following a very wet spring across the Great Lakes and Upper Mississippi
Valley, precipitation has been limited over the past several weeks. The most
recent release of the U.S. Drought Monitor shows expansion of abnormally dry
conditions across parts of the region. WPC`s week-1 forecast indicates below
normal precipitation and above normal temperatures in this area. Above normal
temperatures are forecast to continue into week-2 with only near normal
precipitation favored. Therefore, a possible risk of ROD is posted for parts of
the Upper and Middle Mississippi Valley and Great Lakes region.



Multiple model ensembles depict increasing tropical moisture and convection
over the Gulf of America during the forecast period, potentially associated
with a tropical wave moving into the region. Model solutions keep much of this
enhanced convection south of the CONUS, but a plume of this moisture is favored
to move over Florida during week-2. The PETs from the ECMWF and GEFS both
indicate at least a 20% chance of 3-day precipitation exceeding 1 inch
throughout the forecast period. Uncalibrated probabilities from the GEFS and
ECMWF reach the above thresholds as well, with a bullish ECMWF pushing
probabilities of 3-day precipitation totals exceeding 1 inch over 50% for
southern Florida. The signal weakens a little in both models towards the end of
week-2 though, so a slight risk of heavy precipitation is posted for the
Florida Peninsula valid Jun 8-12. Although a flooding hazard is not being
issued at this time, localized urban and flash flooding is possible given
Florida`s flat topography and the potential for widespread heavy rain.



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: Danny Barandiaran

$$