Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
350 AM EDT Tue Mar 28 2023

Valid 12Z Tue Mar 28 2023 - 12Z Thu Mar 30 2023

...Powerful storm system brings more heavy rainfall/mountain snow to the
West with cooling temperatures...

...Heavy rain with the potential for flash flooding continues in the
Southeast Tuesday...

...Chance for light snow over the Interior Northeast and Great Lakes;
temperatures remain very chilly in the Northern Plains...

A powerful Pacific storm system is forecast to move inland early Tuesday
morning, bringing high moisture and subsequently increasing precipiation
across the West Tuesday-Wednesday. Locally heavy rainfall of several
inches is forecast over the central California coast Tuesday. A Slight
Risk of Excessive Rainfall (level 2/4) has been issued as rainfall will
spread into higher elevations of the coastal ranges following temporarily
rising snow levels, increasing the risk for runoff into local rivers and
the potential for rapid onset flooding. Antecedent conditions also remain
very wet given the repeated rounds of heavy rainfall the last few months.
Very heavy snow is forecast for higher elevations of the northern coastal
ranges and the Sierra, where totals by late Wednesday will likely be
upwards of 1-3 feet. Winds will also remain rather gusty Tuesday over
northern California and adjacent areas of southern Oregon and western
Nevada. Additional moisture spreading inland over the Great Basin will
bring moderate to locally heavy snow to the Blue Mountains of Oregon, the
Saw Tooth Range of Idaho, and higher elevations of the central mountain
ranges of Nevada. Little to no accumulating snow is expected for lower
elevation valley locations. High temperatures will continue to be below
average for much of the West Tuesday-Wednesday, with highs in the 30s and
40s for the Northern Rockies/Great Basin and the 50s for most of
California. In fact, some of these highs across California will be close
to record-tying/breaking low maximum temperatures for the date. Highs over
the Pacific Northwest will rise a bit higher into the 60s, and warmer air
flowing northward ahead of the approaching Pacific front will push highs
into the 60s and 70s for the Southern Rockies and the 80s for portions of
the Desert Southwest Wednesday.

A quasi-stationary front still lingering over the Southeast Tuesday will
once again be the focus for heavy rain producing storms and the potential
for flash flooding. Anomalously high Gulf moisture will continue to reside
along and south of the front, helping to fuel heavy rain rates of 1-2" per
hour. The quasi-stationary nature of the front will also tend to lead to
overlapping storm development and motions that will contribute to heavier
rainfall totals, potentially as high as 2-4". A Slight Risk of Excessive
Rainfall is in effect for portions of the central Gulf Coast as these
storms will overlap areas that have already seen heavy rainfall the
previous day, contributing to wet antecedent conditions and raising the
risk for some scattered instances of flash flooding. An upper-level
shortwave will help to push this front south over the Gulf overnight
Tuesday/early Wednesday morning, likely bringing an end to the showers and
thunderstorms that have plagued the region for days. Seasonable high
temperatures in the upper 60s to low 70s are forecast for areas of the
Southeast closer to the Atlantic and Gulf Coasts. Highs will be a bit
cooler in the 50s and low 60s further north into the Tennessee Valley and
west into Texas as a secondary cold front has passed into the region.
Downsloping winds east of the Rockies over the Southern High Plains will
warm temperatures up into the 70s Tuesday.

An upper-level shortwave and associated surface frontal system will pass
over the Great Lakes Tuesday and move over the Interior Northeast
Wednesday. The system will trigger snow showers with the chance for some
light accumulations along the Upper Great Lakes and for higher elevations
of the Interior Northeast. A cold, Canadian airmass will push southward
over the Northern Plains Tuesday and Central Plains/Upper Midwest
Wednesday following the passage of the cold front, bringing chilly, below
freezing high temperatures. Morning lows will be frigid and well below
average for late March, with temperatures dropping below zero over
portions of northern Montana, North Dakota, and Minnesota Wednesday
morning. Further east, temperatures will be more seasonable. Highs Tuesday
and Wednesday will be in the 40s for the Lower Great Lakes/Interior
Northeast/New England and upper 50s to low 60s for the Mid-Atlantic. Highs
in the upper 40s to low 50s across the Ohio Valley Tuesday will warm up to
near 60 Wednesday.

Putnam


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