WPC Frontal Systems Short Term Forecast

The forecasts depicted below combine WPC forecasts of fronts, isobars and high/low pressure centers with the NDFD depiction of expected weather type for days .5 to 2.5 ahead. Each frame represents 6 hours. A short range forecast discussion for the CONUS is available below the short term loop.

FXUS01 KWBC 292014
PMDSPD

Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Sat Aug 29 2026

Valid 00Z Sun Aug 30 2026 - 00Z Tue Sep 01 2026

...Strong to severe thunderstorms possible across parts of the
Great Basin into tonight...

...Strong thunderstorms expected to move across the Northern
Plains later on Sunday...

...Slight Risk of excessive rainfall across the Four Corners
region Sunday and Monday...

A more active weather pattern is expected to develop across the
western U.S. as a couple of upper-level low/troughs are forecast
to move through the region. Showers and embedded thunderstorms
ahead of the leading trough have already triggered across the Four
Corners states into southwestern Wyoming this afternoon. The Storm
Prediction Center is highlighting the vicinity of northern Utah as
most susceptible to a slight risk of severe thunderstorms through
tonight. �In addition, WPC is highlighting a slight risk of
excessive rainfall across the northern Great Basin and portions of
Arizona through tonight. �The associated heavy rain will create
mainly localized areas of flash flooding, with urban areas, roads,
small streams, narrow canyons/gullies, and burn scars being the
most vulnerable.

From Sunday into Monday, the next upper-level trough is forecast
to move onshore across California toward the Great Basin. This
more subtle trough could become more amplified and bring a higher
chance of more widespread showers and thunderstorms for the Four
Corners states. Therefore, WPC has expanded the slight risk of
excessive rainfall for this region for both days. Areas of heavy
rain may lead to localized
rapid runoff from streams leading to flash flooding.

Meanwhile, fine and cooler-than-normal temperatures for late
August have overspread the entire northeastern quarter of the
country behind a cold front. The trailing portion of the front
will remain nearly stationary across the Southeast, where showers
and thunderstorms are expected to be most active during the
late-day hours with localized flooding possible. A weak
low-pressure area just off the central to eastern Gulf Coast will
also maintain a good chance of showers and thunderstorms nearby
for the next couple of days. Showers and thunderstorms can be
expected to be most active in the late-day hours across the
Sunshine State.

The trough moving through the Pacific Northwest will first bring
showers and embedded thunderstorms from west to east closer to the
Canadian border for the remainder of this weekend. Meanwhile, a
low-pressure wave is gradually developing over the northern
Plains. As the main trough ejects eastward near the U.S.-Canadian
border Sunday into Monday, expect a round of strong thunderstorms
to sweep from west to east across the northern Plains later on
Sunday, reaching the upper Midwest overnight Sunday or early
Monday. Otherwise, expect some showers and a few embedded
thunderstorms across the Great Lakes to northern New England as a
reinforcing cold front dips into the region through this weekend.


Kong


Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php

Extreme Heat Key Messages available at:
https://www.wpc.ncep.noaa.gov/key_messages/LatestKeyMessage_1.png




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• NDFD Rain (Chance) – There is chance of measurable rain (≥0.01″) at the valid time.
• NDFD Rain (Likely) – Measurable rain (≥0.01″) is likely at the valid time.
• NDFD Snow (Chance) – There is chance of measurable snowfall (≥0.01″ liquid equivalent) at the valid time.
• NDFD Snow (Likely) – Measurable snow (≥0.01″ liquid equivalent) is likely at the valid time.
• NDFD Mix (Chance) – There is a chance of measurable mixed precipitation (≥0.01″ liquid equivalent) at the valid time.  “Mixed” can refer to precipitation where a combination of rain and snow, rain and sleet, or snow and sleet are forecast.
• NDFD Mix (Likely) – Measurable mixed precipitation (≥0.01″ liquid equivalent) is likely at the valid time.  “Mixed” can refer to precipitation where a combination of rain and snow, rain and sleet, or snow and sleet are forecast.
• NDFD Ice (Chance) – There is a chance of measurable sleet and/or freezing rain (≥0.01″ liquid equivalent) at the valid time.
• NDFD Ice (Likely) – Measurable sleet and/or freezing rain (≥0.01″ liquid equivalent) is likely at the valid time.
• NDFD T-Storm (Chance) – There is a chance of thunderstorms at the valid time.   Areas are displayed with diagonal hatching enclosed in a dark red border.
• NDFD T-Storm (Likely and/or Severe) – Thunderstorms are likely and/or the potential exists for some storms to reach severe levels at the valid time.