…Clipper system to bring periods of moderate to heavy snow and gusty
winds to the northern Plains and Upper Midwest/Great Lakes the next couple
of days…
…Showers and storms continue into the day Wednesday for the
Ohio/Tennessee Valleys with some locally heavy rainfall and isolated flash
flooding possible…
…Well above average temperatures continue for much of the lower 48…
Lower elevation/coastal rain and higher elevation snow will linger into
the early morning hours Wednesday over the Pacific Northwest and northern
Great Basin/Rockies as an upper-level wave departs the region. The wave
will then pass over the northern High Plains, leading to lee cyclogenesis
and the organization of a clipper system that will drop east-southeastward
over the Plains and Midwest the next couple of days. Strengthening moist
southerly flow over colder air to the north will bring an intensifying
band of snow to the northern Plains Wednesday evening and into the
overnight hours. Winter Storm Watches have been issued for northern and
eastern North Dakota and northwestern Minnesota where 3-6 inches of snow,
locally higher, can be expected. A wintry mix will be possible to the
south of the heaviest snow with some snow and light ice accretions
possible from eastern Montana southeastward through western North Dakota
and into eastern South Dakota. In addition, very strong, gusty winds are
expected across the northern Rockies and High Plains Wednesday into
Thursday. This will lead to blowing snow and low visibility where snow is
either falling or remains on the ground. The system will pass through the
Upper Midwest/Great Lakes Thursday, bringing some moderate to locally
heavy snowfall, particularly across portions of northern Wisconsin.
Showers and thunderstorms continue this morning ahead of a cold front
stretching from the Ohio Valley southwest through the Tennessee/Lower
Mississippi Valleys and into the southern Plains. Some locally heavy
rainfall is expected across the Ohio and Tennessee Valleys where storm
motions more parallel to the slow moving front will lead to a few repeated
rounds of storms. Isolated flash flooding will be possible particularly
across the Tennessee Valley where local soil conditions are more
saturated. The boundary will become more progressive by Wednesday
afternoon and sweep eastward across the Southeast and to the East Coast
into Wednesday evening, with some more isolated storms possible. Moist
flow along a warm front lifting northward ahead of the system will also
bring moderate rainfall to the coastal Northeast as well as the potential
for some accumulating snow for higher elevations of the interior Northeast
Wednesday afternoon through the early morning hours Thursday.
Precipitation should come to an end for all but Florida by Thursday
afternoon as the front pushes into the Atlantic.
Elsewhere, thunderstorms remain in the forecast for South Florida
Wednesday with some very heavy downpours and isolated flooding possible
for urban areas. Extreme to Critical Fire Weather conditions have also
been outlined by the Storm Prediction Center in the Los Angeles vicinity
as gusty winds and dry conditions remain in place. Precipitation chances
will return to the Pacific Northwest by Thursday evening as another
Pacific system approaches the region. Much of the lower 48 will continue
to see well above average temperatures over the next couple of days, with
highs running 10-20 degrees above average for the Southeast Wednesday
(60s-70s), the south-central U.S. Thursday (60s-70s), and the West through
Thursday (40s-50s interior, 60s-70s West Coast and Deserts). The Northeast
will be more seasonable with highs in the mid-30s (interior) to low 50s
(coast). One region that will see much colder temperatures will be the
Northern Plains/Upper Midwest, where highs will mainly be in the teens and
20s and gusty winds will lead to even colder wind chills. The northern
High Plains will see some relief Thursday as downsloping winds bring
warmer temperatures.
Putnam
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php