Yesterday morning, there was a possibility of significant snowfall event occurring from the Mid-Atlantic into New England today (Tues., Jan. 21, 2014) into Wednesday (Jan. 22, 2014). That potential has been fast transforming into reality.
Forecasts now indicate that a storm system that was developing over Arkansas last evening will race rapidly northeastward into the Mid-Atlantic region by early this morning (Fig. 1 and Fig. 2). Snow started to develop and spread across parts of the Ohio Valley overnight and is expected to rapidly expand in areal coverage and intensity as the storm system begins to develop along the Delmarva (Delaware-Maryland-Virginia) coast today (Fig. 3). Computer models indicate that the intensification will approach “meteorological bomb” status (pressure drops of 24 millibars or 0.70 inches of mercury in 24 hours). This system should experience a pressure fall of at least 21 millibars (0.62 inches of mercury) between 8:00 a.m. E.S.T. today and the same time tomorrow, Wed., Jan. 22, 2014 (compare Fig. 2 and Fig. 4). Fig. 5 shows the storm system, as it exits the U.S. region late on Wednesday. Millibars are real pressure units; inches of mercury measure pressure via the height of a mercury column (not a pressure unit per se).
Forecasters are predicting more than 4 inches of snow across the impacted area (Mid-Atlantic to New England), with amounts locally up to a foot or more (Fig. 6). Winds will create snowdrifts several feet high, especially along Mid-Atlantic and New England coastal areas.
Due to the significant temperature drop that is expected to accompany the storm system, typical road chemicals will be hard-pressed to melt the accumulating snow. Thus, roadways from the Mid-Atlantic northeastward will quickly become snow-covered. Traffic, driving over the snow, will compress and partially melt the snow, creating an icy underpinning.
Winds will increase, especially along the coast and in offshore waters. This will lead to lowering wind chills (well below zero in most locations near and within the storm’s main snowy impact area), blowing and drifting snow and occasional near zero visibilities. Offshore, storm force winds (possibly exceeding 65 miles per hour) will create waves likely exceeding 20 feet in height.
Look, too, for the usual spate of impacts – flight delays and cancellations, power outages, multi-car traffic accidents and the clearing of supermarket shelves of some key items (bread, milk, TP and the like).
What is perhaps most amazing about this developing storm system is how it is evolving from “nothing.” Even late yesterday afternoon cloudiness was lacking anywhere near the storm’s humble beginnings. Yet, computer models and weather forecasters were able to predict its intensification (pressure change, wind, precipitation) and storm track quite accurately.
© 2014 H. Michael Mogil