Fig. 1: NOAA/NWS weather watch, warning and advisory areas.
Discussion: Two areas of snow start the week with another arctic air mass sandwiched in-between. By tonight, a large area of moderate snow shifts to West Virginia northeastward into New England along a cold front and north of a warm front. Meanwhile, moderate snows also develop in the Central Rocky Mountains and western Great Plains. Each snowfall region receives several in. of snow. In-between, a new arctic air mass wedges into the Great Plains extending east to the Ohio Valley. By Wednesday morning, the cold air mass is into the East and extends southward to the Gulf Coast. Temperatures are below zero Wednesday morning from north/west New England to western Pennsylvania and westward to the Upper Midwest (where -20’s are common). The 32F line reaches northern Texas to Louisiana and into Georgia. More snow, sleet and ice develop in western Texas Tuesday night. Interestingly, a mild Pacific high wind event pushes the arctic air out of the northern Great Plains Wednesday and replaced by somewhat milder air (which eats snow cover). Temperatures reach the low 40’s by Wednesday afternoon.
Another cold air mass out of Canada cuts-off the temporary northern Great Plains warming midweek. The next cold front drops into the East/Southeast U.S. Friday night and on Saturday morning may spawn a Northeast U.S. coastal snowstorm. Both the GFS and ECM indicate a substantial snowfall for southeast/east New England Friday night/Saturday (Fig. 2-3). Southeast Massachusetts receives >1 foot of snow from this storm.
Fig. 2-3: GFS and ECM 24-hour snowfall forecasts valid 1PM FRI to 1PM SAT.
For now, the high wind driving additional wildfires in the Los Angeles Basin have eased. However, more high wind is possible middle and late week in this region.
The latest U.S. gas population weight HDD forecast indicates minor changes from 24 hours ago. The forecast trend remains out of the deep cold indicated for this week and gradually toward normal national demand by Feb. 4-10 (Fig. 4). The GFS OP was notably warmer in the extended-range as the model warms the South. Will that trend continue at midday today?
The selected cities HDD forecasts for the U.S. were updated yesterday and are on the CIC website.
Fig. 4: U.S. gas population weight HDD forecast using all models, their consensus, comparison with 24 hours ago and the 30-year/10-year normal.