Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
303 PM EDT Fri Jul 30 2021
Valid 00Z Sat Jul 31 2021 - 00Z Mon Aug 02 2021
...Strong to severe thunderstorms with locally heavy rain across parts of
Nebraska tonight and then toward the Middle Mississippi Valley early on
...More monsoonal moisture expected across the interior western U.S. with
increasing focus over central Colorado and the northern Great Basin...
...Excessive heat continues for the interior Pacific Northwest, central
U.S., and Deep South into the weekend before much cooler temperatures
overspread these regions...
A deepening low pressure system entering the Canadian Maritimes tonight
will usher in a much cooler and drier airmass to the Northeast, Great
Lakes, and Mid-Atlantic through the weekend. This will bring welcome
relief after the recent spell of summer heat and humidity across parts of
these areas. Much of the heat and tropical humidity will remain across the
central Plains, Deep South, and into the Southeast this evening ahead of
the trailing front. Heat indices well above 100 degrees are likely
throughout these regions. Relief is on the way, but not until the end of
the weekend for some as much cooler temperatures enter from the north.
Meanwhile, a low pressure wave developing over the central High Plains is
forecast to trigger organized thunderstorms that could become severe this
evening across parts of Nebraska before moving toward the Middle
Mississippi Valley into Saturday morning. Isolated tornadoes, damaging
wind gusts, and large hail are possible. In addition, heavy rain
associated with the thunderstorms could trigger flash flooding.
Over the western U.S., a persistent ridge of high pressure aloft will
continue to sustain the excessive heat across the interior Pacific
Northwest through Saturday. High temperatures are forecast to reach into
the upper 90s and triple digits, which equates to around 10 to 20 degrees
above average. Farther south, monsoonal moisture continues to bring much
needed rainfall to the drought-stricken regions of the West. The broad
area of monsoonal showers and thunderstorms is expected to show increasing
focus across central Colorado as well as spreading further north into the
northern Great Basin during the weekend, where the threat of heavy
rainfall and flash flooding will increase.
Lastly, Air Quality Alerts are currently in effect for portions of Idaho,
Montana, Wyoming, Colorado, Minnesota, Wisconsin, and Iowa due to smoke
associated with ongoing wildfires over western North America being
advected into the regions by the prevailing north-northwesterly winds.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php