Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
400 PM EDT Thu Apr 18 2024

Valid 00Z Fri Apr 19 2024 - 00Z Sun Apr 21 2024

...Severe weather and isolated flash flooding mostly likely over the
Midwest into the Ohio Valley in early Friday with thunderstorms extending
southwest into Texas...

...Wet snow and wintry mix over the central High Plains on Saturday as
heavy rain threat develops and expands over Texas...

...Unseasonably warm across much of the South and Southwest as cold air
from Canada pours south into the Great Plains...

A relatively progressive weather pattern is forecast to establish across
the nation as we head into the weekend.  This progressive pattern will
kick a relatively slow-moving low pressure system further out into the
Atlantic while allowing a cold air mass from Canada to pour southward into
the Great Plains.  A low pressure wave currently developing along the
boundary of the cold air mass over the Midwest will bring an enhanced
threat of severe thunderstorms across the Midwest tonight, moving into the
Ohio Valley early on Friday.  A slight chance of severe thunderstorms is
forecast to extend farther southwest into central Texas near the trailing
portion of the cold front.  In addition to the severe weather threat, the
heavy rain associated with the thunderstorms may result in flash flooding
concerns at some places for aforementioned areas.

By Friday, the cold front is forecast to move steadily east toward the
East Coast.  Showers and thunderstorms will likewise move farther east out
of the Ohio Valley and into the Appalachians, reaching into the interior
Mid-Atlantic, Southeast, and New England by Friday evening.  The severe
weather threat is expected to be not as high on Friday for these areas. 
Saturday will see these showers and storms steadily exiting the East Coast
as the cold front pushes off the coast into the Atlantic.  However,
interior New England will see the showers linger due to the arrival of a
reinforcing cold front from Canada.

As a large dome of high pressure system associated with the Canadian cold
air mass settles into the Great Plains, the upslope dynamics will set up
the opportunity for wet snow to develop over the central High Plains on
Saturday, mixing with rain during the day.  Meanwhile, as an upper trough
moves farther east into northern Mexico on Saturday, the associated
dynamics will support an expanding area of rain over the southern Plains
as the trough interacts with moist air returning from the Gulf of Mexico. 
It appears that the threat of heavy rain threat will expand through
eastern Texas by the end of the forecast period on Saturday evening.

Much of the western U.S. will remain dry through the next couple of days
but the next Pacific system will likely break the drought later on
Saturday as rain reaches the Pacific Northwest.  Forecast high
temperatures will remain rather warm across southern and southwestern
portions of the country through Saturday but the cold front will dispel
some of the warmth across the Mid-South, Midwest, Great Lakes, and
eventually the Northeast with the passage of the cold front.  In contrast,
cold air will gradually push southward through the Great Plains reaching
into central Texas by Friday.

Kong


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