876
FXUS21 KWNC 161822
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT July 16 2025

SYNOPSIS: There is significantly increased agreement among models regarding
amplified mid-level high pressure across the eastern contiguous U.S. (CONUS)
especially from the beginning to middle of week-2. This translates to greatly
increased signals for extreme heat for areas east of the Rockies. High and
moderate risks for extreme heat are included in todays outlook, with many
areas anticipated to experience heat index values exceeding triple digits (deg
F). Possible surface low formation over the Gulf of America increases the
likelihood for heavy precipitation and resultant possible flooding across the
central Gulf Coast at the beginning of the period. A surface low and trailing
front may bring localized heavy rainfall and thunderstorms to portions of the
Upper Mississippi Valley and western Great Lakes at the beginning of the period.

HAZARDS

High risk of extreme heat for portions of the Middle and Lower Mississippi,
Ohio, and Tennessee Valleys, Thu-Fri, Jul 24-25.

Moderate risk of extreme heat for portions of the Great Plains, Mississippi,
Ohio, and Tennessee Valleys, and Mid-Atlantic, Thu-Wed, Jul 24-30.

Slight risk of extreme heat for many parts of the CONUS east of the Rockies,
Thu-Wed, Jul 24-30.

Slight risk of heavy precipitation for the Central Gulf Coast, Thu-Sat, Jul
24-26.

Slight risk of heavy precipitation for the Upper Mississippi Valley and western
Great Lakes, Thu-Sat, Jul 24-26.

Possible flooding for the Central Gulf Coast.

DETAILED SUMMARY

FOR SATURDAY JULY 19 - WEDNESDAY JULY 23:
https://www.wpc.ncep.noaa.gov/threats/threats.php

FOR THURSDAY JULY 24 - WEDNESDAY JULY 30: There is much better agreement among
the GEFS, ECENS, and CMCE ensemble means indicating amplified mid-level ridging
across the eastern CONUS, with greater positive 500-hPa height anomalies
forecast across this area compared to yesterday. This translates to
significantly increased probabilities in the model guidance and tools for
extreme heat. A high risk of extreme heat (>60% chance) is designated for
portions of the Middle and Lower Mississippi, Ohio, and Tennessee Valleys, Jul
24-25. A broad area is highlighted with a moderate risk (40-60% chance) of
extreme heat for much of the Great Plains, Mississippi, Ohio, and Tennessee
Valleys throughout week-2, with the anticipation of the focus of the heat to
shift from the Middle and Lower Mississippi Valleys westward to the northern
and central Plains by the end of the period as the center of the mid-level
ridge shifts westward. The slight risk of extreme heat covers a greater spatial
expanse to include the Ohio Valley and Mid-Atlantic throughout the period. With
high dewpoints expected, heat index values are expected to exceed the 90th
percentile compared to climatology and triple digits deg F. The National Blend
of Models (NBM) show near record daytime temperatures over the Tennessee Valley
and near record nighttime temperatures across many areas across the East.



Surface low formation is possible over the Gulf of America at the beginning of
week-2 that could support areas of heavy precipitation along the Gulf Coast. A
slight risk of heavy precipitation is posted for the central Gulf Coast, Jul
24-26, where the Probabilistic Extremes Tools (PETs) indicate at least a 20%
chance of 3-day rainfall exceeding the 85th percentile and one inch.
Anticipated saturated soils combined with enhanced rainfall during week-2
support increased risk for possible flooding.



Further north, a surface low and trailing front may bring localized heavy
rainfall and thunderstorms to portions of the Upper Mississippi Valley and
western Great Lakes at the beginning of the period. Therefore a slight risk of
heavy precipitation is designated for these areas Jul 24-26.

FORECASTER: Melissa Ou

$$