Weather Outlook for the U.S. for Today Through at Least 22 Days and a Six-Day Forecast for the World: posted December 12, 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
Thu Dec 12 2024
Valid 12Z Thu Dec 12 2024 – 12Z Sat Dec 14 2024…Great Lakes heavy lake-effect snow expected to continue into Friday
especially along the Snow Belt of the lower Great Lakes……A couple rounds of heavy coastal rain and heavy mountain snow expected
to impact northern California into Sierra Nevada heading into the
weekend……Sub-zero temperatures expected over parts of the northern Plains and
upper Mississippi Valley for the next couple of mornings…As a deep low pressure system races further northward into eastern Canada
and a potent cold front exits New England this morning, an arctic high
pressure system will take over the northern Plains and expand across the
entire eastern U.S. through the next couple of days. Maine will be the
last to clear out from the heavy rain early this morning followed by much
colder temperatures under blustery westerly winds. The resurgence of
arctic air is triggering a new round of heavy lake-effect snow across the
Great Lakes through today and tonight before gradually tapering off on
Friday. The Snow Belt of the lower Great Lakes can expect a foot or more
of new snow, with locations downwind from Lake Ontario possibly getting
more than 2 feet since these locations will be the last to clear out from
the snow late on Friday.Along the West Coast, moisture ahead of the next Pacific cyclone is poised
to overspread much of the Pacific Northwest and a good portion of
California today. The heaviest precipitation is expected to reach
northern California in form of rain near the coast and lower elevations.
A quick round of moderate to heavy snow will then reach the high
elevations farther inland and then along the Sierra Nevada for much of
today. It appears that this latest around of precipitation will taper off
temporarily tonight before the next round of precipitation associated with
the next Pacific cyclone arrives on Friday. Northern California into
southwestern Oregon can expect heavy precipitation Friday night with a
marginal risk of excessive rainfall continuing into Saturday morning by
the end of the short-range forecast period. Lesser amounts of
precipitation are expected for the Pacific Northwest.The arctic high pressure system that is forecast to bring sub-zero
temperatures for the next couple of mornings is forecast to strengthen and
slide east into New England by Saturday morning. This will allow
southerly flow to increase across the southern Plains along with moisture
returning from the Gulf of Mexico by Friday night. Meanwhile, residual
energy associated with the first Pacific system is forecast to exit the
southern Rockies and induce the formation of a low pressure system over
the central Plains by Friday night. Some thunderstorms along with heavy
rain could quickly develop and move across the central Plains early on
Saturday ahead of the new low pressure system. Colder air could support
areas of mixed rain and snow farther north across the north-central Plains
into the upper Midwest in advance of the low pressure center. In the
short-term though, dry, breezy and relatively mild conditions will support
elevated fire danger across the southern High Plains for today.