…A slow moving upper level low to bring heavy rain and flooding
potential to the Mid-Atlantic…
…A strong cold front to produce much below average temperatures across
large portions of the West Tuesday and Wednesday, as well as scattered
thunderstorms and mountain snow…
…Summer-like heat to engulf much of the Heartland; Elevated to critical
fire weather threats for portions of the Upper Mississippi Valley/Northern
Plains and Southwest…
The upper low that has plagued the Southeast with rain and numerous
thunderstorms is finally on the move, first tracking through the Mid-South
today, then into the Great Lakes by Wednesday. The Mid-Atlantic will be
the focus for heavy rainfall through mid-week with the heaviest rainfall
unfolding today. This rainfall is welcomed to much of the region given
some portions of the Mid-Atlantic are experiencing moderate to severe
drought conditions. That said, rainfall rates could become heavy enough to
support a flash flood threat for much of the region. WPC maintains a
Slight Risk (threat level 2/4) for Excessive Rainfall from eastern North
Carolina to as far north as central Pennsylvania. There are also a dearth
of Flood Watches in place for much of Virginia and North Carolina. The
deep fetch of Atlantic moisture will stretch as far west as the Great
Lakes and both the Ohio and Tennessee Valleys where widespread showers and
storms are forecast today. Thunderstorms will be more isolated in nature
in these areas on Wednesday. Showers will advance up into the Northeast
Tuesday night and into Wednesday. WPC maintains a Marginal Risk (threat
level 1/4) in the Mid-Atlantic on Wednesday as additional rounds of heavy
rain and thunderstorms may result in isolated instances of flash flooding.
An active weather pattern is also unfolding in the West as a Pacific storm
system tracks through the Intermountain West today, then into the Northern
Plains on Wednesday. This storm system will be responsible for producing
several weather related hazards in the West. First, strong winds in the
Southwest have prompted the issuance of Wind Advisories and High Wind
Warnings from Southern California today, along with Red Flag Warnings due
to the combination of strong winds and dry fuels that are supporting
favorable fire weather conditions. SPC maintains a Critical Risk area for
fire weather in southeast Arizona, southwest New Mexico, and far western
Texas today. Second, periods of rain are expected for much of the
Northwest and Great Basin today, then over the Northern Plains on
Wednesday. SPC does have a Slight Risk (threat level 2/5) for severe
thunderstorms in the central Dakotas and northern Nebraska on Wednesday.
Third, there is some high elevation mountain snow in parts of Montana and
Wyoming. Over a foot of snow is forecast across Montana’s southwest
mountains, Wyoming’s western mountain ranges, and Wyoming’s Big Horn
Mountains. Treacherous travel for recreation in those areas are likely.
This storm system ushered in a considerably cooler air-mass that will
advance across the western U.S. through mid-week. Temperature anomalies
from the West Coast to the Great Basin and Northern Rockies could be on
the order of 10 to 20 degrees below normal today, with similar temperature
anomalies throughout much of the Intermountain West on Wednesday.
While the West is unusually cool and the East is on the more seasonal side
of the temperature spectrum, the Great Plains and Midwest are getting a
summer preview. The Northern Plains will see yet another day of high
temperatures challenging record highs as temperatures soar into the 90s.
In addition, blustery winds and dry fuels are present in the eastern
Dakotas and western Minnesota, prompting the need for a Fire Weather Watch
for these areas through Tuesday evening. Farther south, the heat grows in
intensity across the Lone Star state with highs in the triple digits along
the Rio Grande Valley and into central Texas. Wednesday sees the footprint
of 80s and 90s temperatures grow across the Heartland with the hottest
temperatures once again making their home in Texas. More opportunities for
both record breaking highs and record warm minimum temperatures will be
common in parts of the Southern Plains and Upper Midwest through
Wednesday. NWS HeatRisk show a growing footprint of Major values,
suggesting the forecasted temperatures can affect anyone without effective
cooling and/or adequate hydration. Residents throughout the Plains should
plan ahead to find ways to stay cool and hydrated, especially in southern
Texas where at least Major heat-related impacts may stick around through
the second half of the week.
Mullinax
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
