Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
329 AM EDT Tue Oct 31 2023

Valid 12Z Tue Oct 31 2023 - 12Z Thu Nov 02 2023

...Crisp autumn airmass to lead to a shivering Halloween throughout much
of the central and eastern United States...

...Snow showers to swing across the Great Lakes and parts of the Midwest...

...Atmospheric River ushers in wet weather to the Pacific Northwest by
midweek...


The spookiest day on the calendar may have a few tricks this time as
record-breaking cold spreads its eerie touch from the southern Plains to
the central/southern Appalachians. A robust high pressure system building
into the central U.S. behind a sharp cold front pushing across the
Southeast will be responsible for the brisk conditions. Highs today are
expected to range from 10 to 30 degrees below average everywhere east of
the Rockies (excluding Florida and southern Georgia). This equates to
Halloween afternoon temperatures only reaching the 40s and 50s for most,
with 30s in the Midwest, Great Lakes, central and northern Plains. As the
night descends, temperatures will be chillingly cold while dipping into
the teens and 20s for most locations, giving even the bravest late-night
trick-or-treaters a shiver. Lows in the 30s will be found throughout the
East Coast and Gulf Coast States. These temperatures could break several
daily records into Wednesday morning from Texas to West Virginia, with
additional cold records possible on Thursday morning from the Lower
Mississippi Valley to the Mid-Atlantic. The main concern with the expected
cold will be associated with frost and temperatures below freezing. Many
areas will end their growing season over the next few days from the
southern Plains to the Mid-Atlantic, including parts of the Deep South.
Exposed water pipes will also be at risk of freezing or bursting if proper
precautions are not taken. Freeze Warnings and Watches as well as Frost
Advisories are in effect. The cold and dry airmass when combined with
gusty winds may also increase fire weather danger across the central Gulf
Coast states, prompting Red Flag Warnings to be issued.

Within this cold airmass in place, a compact area of low pressure cutting
across the Upper Midwest and Great Lakes today will provide the chance for
scattered snow showers. Snow could be locally heavy at times across
western Lower Michigan on the northern side of this system. Lake-effect
snow showers may also lead to a wintry night of trick-or-treating for the
remainder of the Great Lakes region. Remember that the first snow of the
season can be frightful, so be sure to take it slow while traveling and
plan ahead.

Elsewhere, lingering showers over the Carolinas and coastal sections of
the Mid-Atlantic and New England are possible through early Wednesday as
an area of low pressure develops over the western Atlantic. Fear not, as
much of the showers should be light and not put too much of a damper on
evening activities. Heavier rain is expected to impact the Pacific
Northwest by Wednesday evening to kick off the start of November. An
Atmospheric River moving onshore Washington and Oregon will produce a few
inches of rain by the end of the day on Thursday, with warm Pacific air
also rising snow levels above 8000 feet so that even most of the Cascades
experience moderate to locally heavy rain.

Lastly, Santa Ana winds are forecast to gradually wane through midweek
after one more day of gusty conditions today. Wind gusts up to 50 mph are
possible throughout Southern California. When combined with dry vegetation
and low relative humidity, elevated fire weather conditions remain.

Snell

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