National Weather Service United States Department of Commerce

Overview

Note: To see the CWA and Virginia total snow/sleet maps, click here.

An Arctic cold front crossed the area during the night of 1/23 into the morning of 1/24 as 1045+ mb high pressure built from the Midwest to Great Lakes. Temperatures plummeted into the teens with dew points between 0 and -15F by the morning of the 24th. Clouds increased during the day as temperatures barely got above 20F and dew points stayed well below zero inland. Meanwhile, the flow aloft was split with a northern stream shortwave exiting New England and a southern stream shortwave ejecting from the Baja California Peninsula toward Mexico and the southern Plains. The flow aloft was WSW-SW from the Southern Plains to Mid-Atlantic. A plume of subtropical moisture became established east of the shortwave and overran the Arctic airmass that was in place all the way from Texas to the Mid-Atlantic. This moisture plume (along with several disturbances ahead of the main southern stream shortwave) allowed for this to be an unusually long duration winter event, with precipitation for 24-30 hours straight. Light to occasionally moderate snow began during the evening of the 24th with temperatures dropping into the upper teens as the snow began. While it was cold at the surface up to 925-950mb, S to SW winds from 850-700mb allowed warmer air aloft to quickly advect over the area, changing the precipitation to sleet during the early morning on the 25th (and rain near the coast where NE winds allowed for a moderated marine airmass to spread slightly inland but not very far). With very cold surface temperatures, the snow and sleet immediately accumulated on area roadways, making for extremely difficult travel conditions by the morning of the 25th. Precipitation continued during the day on the 25th as a classic CAD regime remained established as the Arctic high retreated toward New England and weak low pressure formed off the North Carolina coast and tracked NNE just off the VA coast. 850mb temperatures warmed to around 10C/50F across a decent portion of the area, with the very shallow cold layer remaining in place from the surface to 2500 ft AGL in most areas west of the Chesapeake Bay. In fact, temperatures at Richmond did not get out of the lower 20s for much of the day with upper teens from Louisa to Farmville. Precipitation turned to liquid (rain or freezing rain) across the eastern shore, eastern VA and NE NC, with mainly sleet farther inland despite the very "warm" 850mb temperatures. Even though a lot of the guidance showed a changeover to freezing rain during the morning of the 25th across much of the area, precipitation remained as sleet until the late afternoon when it changed to freezing drizzle or light freezing rain. The one exception to this was a narrow corridor from Bertie/Hertford Counties to Isle of Wight/Sussex to the VA Middle Peninsula where it did turn to freezing rain earlier in the day. We hypothesized that it remained as sleet longer than expected largely due to how cold it was in the lowest 2000 ft. While many areas received 1-3" (locally up to 5") of sleet, this event was thankfully much less severe than anticipated in terms of power outages since ice accretions were generally no higher than 0.10-0.25". Model analysis soundings for LKU (Louisa, VA), RIC (Richmond), SBY (Salisbury, MD), and ORF (Norfolk) are shown in the environment section. Precipitation finally came to an end between 7-11 PM on the 25th.

nws logo Media use of NWS Web News Stories is encouraged!
Please acknowledge the NWS as the source of any news information accessed from this site.
nws logo