138
FXUS21 KWNC 171803
PMDTHR
US Hazards Outlook
NWS Climate Prediction Center College Park MD
300 PM EDT July 17 2025

SYNOPSIS: Amplified mid-level high pressure is predicted across much of the
contiguous U.S. (CONUS) excluding the West Coast during week-2. This translates
to increased chances for extreme heat for areas east of the Rockies and the
Desert Southwest. Many of these areas could 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, western Great Lakes,
and Northern Plains at the beginning of the period. Dry soils and anticipated
dry, hot conditions support a risk of Rapid Onset Drought (ROD) over Kansas.

HAZARDS

High risk of extreme heat for portions of the Middle and Lower Mississippi,
Ohio, and Tennessee Valleys, Fri-Sat, Jul 25-26.

Moderate risk of extreme heat for portions of the Great Plains, Mississippi,
Ohio, and Tennessee Valleys, and Mid-Atlantic, Fri-Thu, Jul 25-31.

Slight risk of extreme heat for many parts of the CONUS east of the Rockies,
Fri-Thu, Jul 25-31.

Slight risk of extreme heat for the Desert Southwest, Fri-Thu, Jul 25-31.

Slight risk of heavy precipitation for the Central Gulf Coast, Fri-Sun, Jul
25-27.

Slight risk of heavy precipitation for the Northern Plains, Upper Mississippi
Valley and western Great Lakes,  Fri-Sun, Jul 25-27.

Possible flooding for the Central Gulf Coast.

Rapid onset drought risk for parts of Kansas.

DETAILED SUMMARY

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

FOR FRIDAY JULY 25 - THURSDAY JULY 31: The GEFS, ECENS, and CMCE ensemble means
continue to indicate amplified mid-level ridging across much of the CONUS
excluding the West Coast from the end of week-1 throughout week-2. The focus of
the positive 500-hPa height departures are predicted to shift from the eastern
half of the CONUS to the Midwest by the middle of week-2. This pattern enhances
the risk of extreme heat for areas east of the Rockies and the Desert
Southwest. A high risk of extreme heat (>60% chance) is designated for portions
of the Middle and Lower Mississippi, Ohio, and Tennessee Valleys, Jul 25-26. 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, and
Mid-Atlantic 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 middle of the period as the center of the mid-level
ridge shifts westward. The slight risk of extreme heat covers many areas east
of the Rockies with the expansion to western portions of Pennsylvania and New
York. 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
25-27. The Probabilistic Extremes Tools (PETs) indicate at least a 20% chance
of 3-day rainfall exceeding the 85th percentile and one inch, although with
somewhat decreased spatial coverage compared to yesterday. 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 north-central CONUS. The slight
risk has expanded slightly westward to include the Northern Plains, Upper
Mississippi Valley, and western Great Lakes at the beginning of the period, Jul
25-27.



Anomalous dry soils and expected hot, dry conditions supports a risk of Rapid
Onset Drought (ROD) for parts of Kansas.

FORECASTER: Melissa Ou

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