Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 AM EDT Mon Mar 27 2023

Valid 12Z Mon Mar 27 2023 - 12Z Wed Mar 29 2023

...Heavy rain with the potential for flash flooding and severe weather
continues in the Southeast...

...Series of frontal systems increase precipitation chances for the
Northeast Monday...

...Chilly temperatures and the chance for snow across portions of the
Plains and Great Lakes...

...Powerful storm system to bring yet another round of heavy snow/rainfall
to California...

A quasi-stationary boundary draped across the Southeast that was the
trigger for widespread flash flooding and severe weather over the weekend
will be the focus for these threats again Monday. Storms will likely be
ongoing Monday morning near the boundary across portions of central
Alabama and Georgia. Anomalously high moisture continuing to stream
northward from the Gulf will promote heavy rain rates. The
quasi-stationary nature of the boundary will also lead to repeated,
overlapping storm development and motions increasing the potential for
locations to see multiple rounds of heavy rain and higher rainfall totals.
A Slight Risk of Excessive Rainfall has been introduced over this region
as these storms continue over locations that saw heavy rainfall Sunday,
increasing the risk for additional scattered instances of flash flooding.
In addition, some storms may become severe as a moderate to strongly
buoyant airmass remains in place to the south of the boundary with
continued strong flow aloft. The Storm Prediction Center has issued a
Slight Risk for severe weather (level 2/5) over a similar region as the
flash flood risk from southern Georgia into the South Carolina Low Country
for the threat of hail, strong winds, and a tornado or two. By Tuesday, an
upper-level shortwave will help to push a better organized frontal system
south towards the Gulf, helping to clear out the region while keeping
storm motions a bit more progressive and expected rain totals lower
compared to the prior days. However, anomalously high moisture will still
be present keeping the threat of higher rain rates and localized heavy
rain possible. This led to the retention of a Marginal Risk of Excessive
Rainfall (level 1/4) from the Central Gulf Coast east into southern
Georgia and northern Florida. High temperatures will remain above average
across the South Monday with upper 70s to low 80s forecast. Temperatures
will be even warmer in Florida with near record-tying/breaking highs
upwards of 90. Highs will cool into the mid-60s to low 70s for most of the
region Tuesday as the front finally pushes southward into the Gulf.

The frontal system pushing through the South will also move eastward
through the Mid-Atlantic Monday as another cold front over Canada slides
southward into the Interior Northeast. This will increase precipitation
chances regionally for the Northeast, with light to moderate showers for
the Mid-Atlantic and southern New England and a wintry mix into the
Interior Northeast, though little to no accumulations of sleet/snow are
expected. Highs will generally be seasonable for the Interior
Northeast/New England with 40s and 50s forecast. Energetic flow aloft will
help to encourage additional waves of low pressure along the Canadian
front trailing through the Great Lakes and into the Plains, increasing
precipitation chances for these regions as well. A few inches of
accumulating snow are forecast for portions of the Central High Plains
Monday and for the Upper Great Lakes Tuesday. Highs will be a bit below
average over the Midwest as temperatures generally remain in the 40s. Very
chilly, much below average temperatures are forecast for the Plains Monday
with highs in the 20s and 30s. Highs will warm up into the 40s and 50s for
the Central Plains Tuesday. 

A powerful Pacific storm system will approach the West Coast Monday, with
high Pacific moisture quickly overspreading southern portions of the
Pacific Northwest and California and bringing yet another round of heavy
coastal/lower elevation rain and mountain snow. The heaviest rainfall is
expected Tuesday along coastal Central California. There is a Slight Risk
of Excessive Rainfall along the terrain of the coastal mountains as warmer
air moving in will help to raise snow levels and increase the threat of
runoff into downstream rivers, as the entire region remains sensitive to
the risk of flooding given very wet antecedent conditions. Very heavy snow
is forecast for higher elevations of the northern Coastal Ranges and
Sierra Monday-Tuesday, with totals of several feet possible. In addition
to the precipitation, gusty winds are also likely Monday along coastal
California and the Sacramento Valley. Moisture will spread further inland
into the Pacific Northwest and Great Basin Tuesday with a mix of rain and
snow for lower elevation valley locations and accumulating snow for the
Cascades, Blue Mountains of Oregon, and Sawtooth Range of Idaho. High
temperatures will continue to remain much below average for most of the
West Monday, with highs in the 30s and 40s for the Great Basin and
Northern/Central Rockies; 50s for the Pacific Northwest, northern/central
California, and the Southern Rockies; and 60s to low 70s for the Desert
Southwest. Highs will warm up a bit regionally Tuesday as upper-level
ridging briefly builds in following the departure of a trough to the East,
though temperatures over northern/central California will remain
unseasonably cool.

Putnam


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