The Nation’s Weather

…Moderate to heavy rain expected to move across the interior New England
today with gusty winds…

…Showers and thunderstorms expected to reach the Desert Southwest Sunday
night and then the Four Corners Monday morning…

…A round of rain expected to reach Montana Sunday night into Monday
morning with gusty winds…

…One more day of significant heat expected across interior California
and portions of the Southwest for today…

A rather strong low pressure system for late May was tracking into
southern New England early this Saturday morning. This system is forecast
to move northeastward through the rest of New England for the remainder of
today while bringing a round of moderate to heavy rain especially across
the interior sections during the day today along with gusty winds
expanding across the Northeast. The cold front trailing south from the
system center will be pushing well off the East Coast today.
Nevertheless, instability associated with a cold upper-level trough behind
the front could trigger additional scattered thunderstorms across the
Mid-Atlantic region this afternoon, even though temperatures will be
cooler in the wake of the front. Saturday night into Sunday morning, a
reinforcing cold front will bring cooler than normal temperatures from the
Great Lakes through the Northeast and down into the Mid-Atlantic, setting
up a fairly pleasant Sunday to round out the weekend. Some rain/showers
are expected to linger over northern New England Sunday into Monday due to
the proximity of the deep and large low pressure system which will be
taking its time to exit eastern Canada.

Meanwhile, in contrast to the rain and cooling trend in the eastern U.S.,
a strong ridge of high pressure will bring heat and dry weather initially
across much of the western U.S. and into the northern Plains. In fact,
high temperatures reaching daily record levels will be expanding into the
Great Basin, Idaho, and as far north as western Montana today. The
anticipated heat has prompted another day of Extreme Heat Warnings for
portions of southernmost Nevada, southeast California, and northwestern
most Arizona. Meanhwile, Heat Advisories remain in effect for most of
today across the interior valleys of California, portions of Nevada into
eastern Oregon, portions of Idaho and northwestern Montana. Drinking
plenty of water, wearing light colored clothing, and staying in air
conditioned areas is advised as temperatures soar as high as the mid-110s
Fahrenheit in lower desert locations like Death Valley, California. A
cold front from the Pacific is forecast to bring rapid cooling into the
Pacific Northwest later today into Sunday but with minimal rainfall
expected. Farther south and east, surging moisture ahead of the front
across parts of the Rockies and Intermountain West will support high
elevation showers and thunderstorms Sunday afternoon and evening. Given
the enhanced moisture being drawn in, some of these showers and storms
could produce briefly heavy downpours. Across the Desert Southwest,
showers and thunderstorms will be on the increase beginning Sunday as an
upper-level low from the Pacific reaches into northern Mexico. Scattered
thunderstorms can also be expected to develop across the central Rockies
Sunday night. By Monday morning, showers and thunderstorms assocaited
with the upper low will likely spread further northeastward into the Four
Corners region.

Across the northern Rockies into the northern High Plains, a low pressure
system is forecast to develop as the Pacific cold front progresses farther
inland. A swath of moderate to locally heavy rainfall is expected to
develop over Montana (especially central Montana) Sunday night into Monday
morning as a surge of cooler air associated with a Canadian high pressure
system arrives to bring gusty northerly winds.

Across the Sunshine state, scattered showers and thunderstorms are
expected to linger especially for the southern portions of the Florida
Peninsula through the next couple of days due to a stalled front.

Kong

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