…Heavy rain and flash flood threat will continue for portions of the
Southeast this weekend, then the flash flood threat will shift to the
Carolinas/Mid-Atlantic early next week…
…A strong low pressure system will bring unsettled weather to the West
late this weekend/early next week, with wintry precipitation expected at
high elevations…
…Well above average temperatures for the Central U.S. and Northeast;
well below average temperatures for the West…
Though it is now post-tropical, Francine will continue to bring a threat
for heavy rain and flash flooding to portions of the Southeast through
Sunday. The central area of low pressure will gradually sink south towards
the Gulf Coast with a stationary boundary extending to the Southeast Coast
and a cold front extending back towards the Southern Plains. The
stationary boundary will be the main focus for convection this weekend,
and training showers and thunderstorms with locally heavy rainfall will
create a threat for scattered instances of flash flooding. There is a
Slight Risk of Excessive Rainfall (level 2/4) for portions of Arkansas,
Tennessee, Mississippi, Alabama, and Georgia today and Sunday. Flash Flood
Watches are in effect for much of this area, and urban/poor drainage areas
and areas that already received heavy rainfall over the past few days will
be most at risk for flash flooding.
A separate area of low pressure will strengthen along the stationary
boundary extending from the Southeast Coast, which will maintain shower
and thunderstorm chances from Florida to the Carolinas and southern
Mid-Atlantic through early next week. This low pressure system is forecast
to gradually track north along the East Coast early next week and will
bring a heavy rain and flash flood threat to portions of the Carolinas and
Mid-Atlantic. There is a Slight Risk of Excessive Rainfall (level 2/4) for
eastern North Carolina on Monday where scattered instances of flash
flooding will be possible.
In the West, an unsettled pattern is forecast to develop this weekend as a
strong upper low pushes a frontal system across the region. The system
will nudge into the Pacific Northwest today, then move across northern
California, the Great Basin, and the northern Rockies Sunday and Monday.
Widespread showers and thunderstorms will accompany this system, and there
is a broad Marginal Risk of Excessive Rainfall (level 1/4) in effect for
portions of the Northern Rockies and Great Basin on Monday. This system
will also usher in well below normal temperatures, which will allow for
wintry precipitation to fall at higher elevations. A Winter Weather
Advisory is already in effect for portions of the Sierra Nevada where up
to 4 inches of snow may fall Sunday night and Monday. Precipitation
chances will also increase across the Southwest/Four Corners region late
this weekend into early next week as tropical moisture streams north ahead
of Tropical Cyclone Ileana.
Temperatures this weekend will have a large range across the United States
with well above average temperatures in the Central U.S. and Northeast and
well below average temperatures under the strong upper low in the West.
High temperatures will be in the 80s and 90s for the Central U.S. and
Northeast through Monday, which is more than 15 degrees above average for
some areas in the Upper Midwest/Great Lakes. High temperatures in the West
will be near to slightly below average today, then drop to 15 to 25
degrees below average in Oregon, California, and Nevada by Monday. Highs
in the 50s will be common in the Great Basin, and highs will likely only
reach the 30s and 40s in the Sierra Nevada.
Dolan
Graphics available at
https://www.wpc.ncep.noaa.gov/basicwx/basicwx_ndfd.php
