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Winter Storm Threat: Dec 28-29 (initial call)

Another quick-turnaround forecast as the next system looks to bring widespread 1-4″ totals to the Mid-Atlantic, with higher totals in the central Appalachians. Marginal boundary layer temperatures and initial surface winds out of the southeast makes finding that 1″ boundary a challenge yet again. Luckily, the upper-level temperatures are cooperating more this time around, so if your surface temperature is at or below freezing you’ll almost certainly be getting some accumulation. Mixing areas will mostly be rain/snow, but some sleet is still possible.

I’ll be traveling tomorrow, so if/when I update it will be in the evening. Verifications will come once these back-to-back events slow down!

Winter Storm Threat: Dec 26-27 (only/final call)

Forecast confidence is low as most of the snow falls at the front end of the system before many areas switch over to mixed precipitation and/or rain. Very small changes in temperature at various levels of the atmosphere could lead to significantly different snowfall totals, especially east of the mountains. The northwestern parts of the forecast region could/should stay all snow throughout the event, which roughly matches up with the 8-12+ inch area along and west of the mountains.

There will be some lingering snow in the central Appalachians at the end of the event as cold, northwesterly flow takes over.

Winter Storm Threat: Dec 21-23 (final call)

No major changes to the forecast, though I did decide to go a bit more aggressive with the totals in some areas. The most notable changes were in northern PA and southwestern NY, with an 8-12 inch contour added as lake-effect off of Lake Erie helps drive up totals. The back edge of the main area of precipitation is expected to change over to snow, but how much of that actually accumulates ahead of the later snow is uncertain.

Localized totals of >12 inches are possible within the 8-12 inch contours.

Winter Storm Threat: Dec 21-23 (initial call)

Most if not all of the snow with this disturbance will accumulate well behind the cold front, with lake-effect snow bringing some respectable totals to western PA and WV. Most of the snow will fall Friday morning through Saturday afternoon. Low-level temperatures will limit accumulations across central and eastern PA.

South and east of the 1″ line could see snow in the air Friday, with little to no accumulation expected.

Snowfall Verification for Nov 27

A bit more when right than wrong with this forecast, though there was a decent chunk of the forecast that was in fact wrong. Had the general theme and possible snowfall amounts in the right neighborhood. Big errors can be noted in south-central PA, where lower snowfall rates kept much from accumulating. Northern PA and northern NJ over-performed a bit, especially in northern NJ where better banding set up. Rain/snow line and snowfall amounts in southeastern PA, central NJ and in the NYC area were pretty good.

B- forecast overall.

Winter Storm Threat: Nov 27 (only/final call)

This storm will drop a rain/snow mix south of the 1 inch line, with a slushy coating possible across northern MD into Philadelphia. Higher elevations will do better with this event, especially from southern PA southward.

A rather weak disturbance will slide across the region tonight into tomorrow, bringing wintry precipitation to the region from DC northward. South of DC will be mostly (or all) rain, with a rogue snowflake or two possibly mixing in with the rain, especially if the precipitation rates are high. Temperatures are cool enough aloft for snow, but the low-level temperatures are forecast to be above freezing up through southern PA, which will keep accumulations limited on the southern edges. If low-level temperatures hold warmer than expected, snow totals will be lower than forecast.