Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
426 PM EDT Sun Mar 26 2017
Valid 00Z Mon Mar 27 2017 - 00Z Wed Mar 29 2017
...There is a moderate risk of severe thunderstorms over portions of the
...Rain/freezing rain possible over parts of the Northeast...
...Heavy rain and snow across the Northwest U.S. through Monday...
A complex system will impact much of the Central/Lower plains and eastern
U.S. over the next couple of days. Two main low pressure systems will be
in play: the first will move across the Upper Great Lakes tonight and
into Southeast Canada Monday as it continues to weaken, and the second
will continue to strengthen as it moves across the Southern Plains
tonight, and into the Mid/Lower Mississippi Valley Monday. This second
system will eventually traverse the Ohio Valley Monday night, before
reaching the Atlantic Coast by Tuesday. A series of frontal boundaries
will connect these two systems, and will be the epicenter for
precipitation and convective activity.
In the northeast U.S., precipitation will be in the cold sector of the
northern most low pressure system, falling as a freezing rain over the
next couple of days. Freezing Rain Advisories and Winter Weather
Advisories are in effect from far eastern New York upwards through Maine.
Widespread rain, heavy at times, and scattered thunderstorms will occur
from the Mid Atlantic to the Upper Great Lakes tonight into Monday on the
warm side of the low pressure system, especially along the frontal
boundary regions. This will eventually dissipate throughout the day Monday
as the system continues to weaken and move northeast.
For the strengthening Southern Plains system, showers and thunderstorms
are also expected generally just ahead of the associated cold front. Given
the strong nature of this system, and the strong pull of warm and unstable
air flowing in off the Gulf of Mexico, this will combine with ample lift
along the frontal boundary and low pressure system, creating the
ingredients necessary to produce strong to severe convection. The Storm
Prediction Center has outlined a portion of south central Oklahoma and a
small portion of northeast Texas as being in an enhanced risk for severe
weather this evening and overnight, with an enhanced and slight risk
expanding farther to encompass much of Oklahoma, portions of Northeast
Texas, and far eastern Oklahoma. High winds, large hail, and tornadoes are
all possible hazards as storms develop. Please refer to the Storm
Prediction Center's web page for more information: www.cps.ncep.noaa.gov.
The area of concern will shift eastward by Monday, with much of the
western Ohio and Tennessee Valleys being outlined in a slight risk for
severe weather during this time.
Over the West Coast, a low pressure system and occluded surface cold front
will move onshore this evening, continuing to move eastward to the Rockies
by Monday evening. The system will produce rain and higher elevation snow
over parts of the Pacific Northwest/Northern California this evening and
overnight, spreading inland and affecting parts of the Great Basin on
Monday, then reaching the Central Rockies/Southwest by Monday evening.
Onshore flow will keep precipitation in place across much of the Pacific
Northwest over the next couple of days. Winter Weather Advisories are in
effect for the highest elevations of the Cascades and the northern half of
the Sierra Nevadas where some locations could see in excess of 10 inches
of total snowfall. The area of low pressure will eventually sink southeast
into the Central and Southern Plains Tuesday into Wednesday, once again
tapping into warm and unstable air flowing inland from the Gulf of Mexico.
This combination may result in another round of showers and thunderstorms,
some of which could be strong to severe Tuesday and heading into mid-week.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php