Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
331 PM EDT Sat Oct 20 2018
Valid 00Z Sun Oct 21 2018 - 00Z Tue Oct 23 2018
...Heavy rainfall threat the lower Texas coast and Rio Grande Valley...
...Much colder air across the Midwest and eastern U.S....
A slow-moving frontal boundary extending from the southern Mid-Atlantic
region to the Gulf coast region will continue to provide the focus for
showers and thunderstorms as it pushes slowly southeast this evening. As
the front begins to move onshore and high pressure settles in, most areas
from the southern Plains to the Mid Atlantic region are expected to see
drier conditions through the remainder of the weekend and into the early
part of next week. However, as the front stalls over the northwestern
Gulf of Mexico, the lower Texas coast and Rio Grande valley are expected
to be a primary exception, with persistent moist onshore winds north of
the boundary supporting periods of locally heavy rain beginning later
today and continuing through Sunday. Given recent heavy rains and wet
soil conditions, a flash-flood watch is effect for this area beginning
this evening and continuing through early Monday. An organizing area of
low pressure along the front may begin to track to the north, extending
this heavy rainfall threat further north along the Texas coast on Monday.
Further to the north, a vigorous reinforcing shot of colder air will push
southeast from the upper Midwest and Great Lakes into the Ohio valley and
central Appalachians this evening and overnight. In addition to ushering
in some of the coldest air of the season so far, showers and thunderstorms
and gusty winds can be expected as this system pushes through.
Temperatures from the Great Lakes to the southern Plains and through much
of the eastern U.S. are expected to be below-normal, with some areas well
below-normal on Sunday. Freeze warnings and frost advisories for Sunday
morning currently extend from portions of eastern Kansas and Oklahoma to
the southern Appalachians.
In the West, a broad upper level system is expected to move into the
southwestern U.S., bringing temperatures down while supporting showers and
thunderstorms across portions of the Southwest and Great Basin beginning
later today and continuing into early next week. Meanwhile, dry
conditions and above normal temperatures are forecast to continue from
northern California and the Pacific Northwest into the northern and
central High Plains.
Graphics available at www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php