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Severe Weather and Excessive Rain in the Ohio and Tennessee Valley; Dangerous Heat in the South

Widespread strong to severe thunderstorms may produce large hail, damaging wind gusts, a few tornadoes, and flash flooding across parts of the lower Missouri Valley into the Ohio and Tennessee Valleys. Dangerous and potentially record-breaking heat continues across parts of Texas, the western Gulf Coast, southern Florida, and Puerto Rico. Read More >

Overview

General Summary: During the evening of January 2, low pressure began to strengthen over Alabama/Georgia as a upper shortwave in the southern stream began to take on a neutral tilt as it tracked over the Tennessee Valley. Meanwhile, a cold front was moving southward across the local area while cold high pressure was centered from the Plains to Great Lakes. Temperatures were still in the 60s with rain and a few thunderstorms across the Wakefield CWA during the evening of 1/2 as the cold front approached. The front eventually moved just to the south of the Wakefield CWA by the early morning on 1/3 as the low started to rapidly deepen as it tracked ENE into South Carolina. Colder air quickly filtered in behind the front as steady precipitation was ongoing, dropping temperatures into the 30s-40s by 4-5 AM on 1/3. Precipitation already changed to sleet/snow across NW portions of the CWA by 5 AM. By 7-8 AM, the rain/sleet/snow line had moved into the Richmond Metro as moderate to heavy precipitation was ongoing thanks to intense frontogenetic forcing. Snowfall rates of 1-2"+ per hour were observed just NW of the metro area with heavy rain and (elevated) thunderstorms across SE VA and NE NC. The rain/snow line did not progress much to the SE through 9-10 AM largely due to a warm layer between 850 and 700 mb that kept the precipitation in the form of rain or sleet. Finally during the late morning through early afternoon, precipitation quickly changed over to snow from NW-SE across the entire area as the very strong area of low pressure moved offshore. Temperatures dropped to 29-33F across much of the area by mid afternoon. A widespread 6-11" (with locally higher totals) of heavy, wet snow fell from the central Virginia Piedmont to Dorchester County, MD. 2 to 7 inches fell from the Richmond metro to the rest of the Lower Eastern Shore, while only a trace to 2 inches fell over south/southeast VA. In addition, moderate to major tidal flooding was observed in the Lower Chesapeake Bay and Atlantic coast of SE VA and NE NC due to strong NE winds (with gusts over 50 mph at times). 

Snow: A strong band of frontogenetic forcing around 700 mb, along with plenty of slantwise instability (as evidenced by negative EPV and model cross sections). In addition there was even a little bit of elevated CAPE in the area where it was snowing during the morning. This led to intense banded snowfall that produced rates in excess of 1-2" per hour at times. While the best frontogenetic forcing generally stayed just to the NW of the Richmond Metro (and extended into Dorchester County, MD) through much of the morning, it gradually moved into the metro area during the late morning-early afternoon, allowing for some areas to pick up a quick few inches of snow. The bands of snow weakened as they moved into SE VA as the low pressure system quickly exited to the northeast. The weight of the heavy, wet snow downed several trees across the NW portion of our area, resulting in widespread power outages. There were several counties where 70-90% of residents were without power. At the peak of the event, nearly 450,000 residents were estimated to be without power in the state of Virginia. For many parts of our area, this was the largest snow event since 12/9/2018. In Louisa and Goochland Counties, the tree/infrastructure damage was on par with what occurred during Hurricane Isabel. The excessive amounts of heavy, wet snow were largely responsible for a closure of a portion of I-95 from Caroline County to north of the CWA border that lasted over 24 hours.

Tidal Flooding/Wind: The tightening pressure gradient just to the north of the surface low allowed for northeast winds to gust to 50+ mph during the morning through afternoon on 1/3, with occasional gusts of 60-70+ mph in a few locations. This allowed for water to rapidly surge into the Lower Chesapeake Bay and Atlantic coast of VA and NC. As mentioned above, moderate to major tidal flooding was observed in these areas. In fact, water levels at Sewell's Point (and other locations) eclipsed levels seen during recent tropical events (such as Hurricane Dorian). 

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