Weather Outlook for the U.S. for Today Through at Least 22 Days and a Six-Day Forecast for the World: posted December 11, 2024
This article focuses on what we are paying attention to in the next 48 to 72 hours. The article also includes weather maps for longer-term U.S. outlooks (up to four weeks) and a six-day World weather outlook which can be very useful for travelers.
First the NWS Short Range Forecast. The afternoon NWS text update can be found here after about 4 p.m. New York time but it is unlikely to have changed very much from the morning update. The images in this article automatically update.
Short Range Forecast Discussion
NWS Weather Prediction Center College Park MD
Wed Dec 11 2024
Valid 12Z Wed Dec 11 2024 – 12Z Fri Dec 13 2024…Widespread heavy rain and severe thunderstorm treats spreading up the
East Coast today and through New England into tonight……A surge of cold air into the eastern U.S. today will be followed by a
reinforcing surge of arctic air into the northern U.S. through the next
couple of days……Another round of significant lake effect snow expected through the next
couple of days downwind of the Lakes...The stage is set for a rapidly intensifying low pressure system to track
up the East Coast today. A potent cold front trailing southwest from the
center of this elongated low pressure system will be the focus for heavy
rain, blustery winds, and strong to severe thunderstorms. Ahead of the
front, warm and moist air streaming in from the nearby Atlantic and Gulf
of Mexico will interact more vigorously with a jet stream aloft to develop
and expand the coverage of showers and thunderstorms, first across the
Southeast and the Carolinas this morning, followed by the Mid-Atlantic
states during the day, and into New England this evening. The highly
dynamic nature of this front will likely trigger formation of strong to
severe thunderstorms. This is especially the case across eastern North
Carolina this afternoon, and into southern New England this evening, where
the Storm Prediction Center has issued a Slight Risk (level 2 of 5) for
severe thunderstorms capable of producing damaging wind gusts. Elsewhere
along the Eastern Seaboard, the main concern will be a period of heavy
rain with embedded strong thunderstorms and intense downpours. Despite
much of the region currently experiencing moderate to extreme drought
conditions, the rain, while mostly beneficial, could lead to some
localized instances of flash flooding. The more urbanized locations and
poor drainage areas would have the greater risk of flooding issues.Behind the potent cold front sharply colder air will surge into the East
Coast from the north and northwest. A period of accumulating wet snow can
be expected to spread up the western slope of the entire spine of the
Appalachians from south to north today through tonight. Meanwhile, a
reinforcing shot of arctic air is plunging into the northern Plains and
will overspread much of the northern tier states through the next couple
of days. High temperatures the next couple of days will be roughly 10 to
as much as 30 degrees below normal.Attention then turns to yet another round of significant lake effect snow
downwind of the Great Lakes through the next couple of days. The
aforementioned surge of arctic air will stream across the still relatively
warm Great Lakes and ignite intense bands of lake effect snow, initially
downwind of Lakes Superior and Michigan on today and then downwind of
Lakes Erie and Ontario tonight into early Thursday. By the time the snow
starts to taper off on Friday, snowfall totals of 1 to 2 feet are likely
in the favored Snow Belt across portions of northwest and western New York
State, far northwest Pennsylvania, far northeastern Ohio, the Upper
Peninsula of Michigan and the western portions of the Lower Peninsula of
Michigan.Along the West Coast, moisture ahead of the next cyclone from the Pacific
is poised to overspread much of the region through the next couple of
days. Northern California will see heavy coastal rain by this evening,
followed by heavy mountain snow farther inland and down the Sierra Nevada
where a foot or more of new snow is forecast through Thursday. It appears
that this round of precipitation will mostly taper off Thursday night
prior to the arrival of the next Pacific system.