Convective development begins in the evening hours of Friday as the first thunderstorms of the year for most of the region. At the moment, the areas most likely to see a thunderstorm are along the I-95 corridor through North Carolina, Virginia, Maryland, Delaware, and New Jersey. The northward extent of the convective development has been tricky to forecast, but the latest HRRR, the 12z NAM, and the 12z HRDPS have suggested that the NYC metro area, Long Island, and the Connecticut coastline will be enveloped by heavy rain
...Widely scattered strong to severe thunderstorms may occur from parts of central/east Texas to the lower/mid Mississippi Valley on Wednesday. At the surface, a deep surface low will develop east/northeast from eastern CO to eastern NE during the period. A cold front will trek east/southeast across the central and southern Plains during the afternoon into overnight hours. Ahead of this feature, convection will likely be ongoing along a dryline/pacific cold front from south-central OK into central TX. Given these combination of factors, the possibility exists for a few mini supercells. The tornado risk will be conditional on the degree of destabilization. Strong wind profiles with effective shear (60+ kt), will conditionally support a damaging wind threat with the more organized segments of the larger-scale convective band expected to move east from OK/TX towards the MS Valley.The strong to severe threat will likely cease coincident with the nocturnal cooling during the evening.
An Enhanced Risk of Severe Thunderstorms is Forecast Today and/or Tonight. Severe thunderstorms are expected this afternoon into this evening from Arkansas/northern Louisiana to the lower Ohio and Tennessee Valleys. A couple of strong tornadoes will be the main threat late this afternoon/evening from northern Mississippi into parts of western/middle Tennessee, along with damaging winds and isolated large hail.
WX Alert: Hazardous Weather OutlookWXD Alert: Post Discussion
. Total snow accumulations of up to two inches and ice accumulations of a light glaze expected due to freezing drizzle. Ice will be more likely late tonight into early Friday morning. In parts of southern Ohio including Wilmington and Cincinnati total snow accumulations of 1 to 2 inches can be expected. Locally higher amounts of 3 or 4 inches are possible in the worst hit areas. Winter Weather Advisories are in effect for the southern regions with snow showers or flurries expected along the periphery.
...Heavy snow for the Sierra... ...Heavy rain possible for Coastal California will lead to excessive rainfall over parts of Southern California.. A deep upper-level low over the Pacific will move onshore over California on Wednesday then moves farther inland to the Northern/Central Plains by Thursday. Moisture associated with the system will stream into California and begin to wane overnight Wednesday. The moisture and energy will aid in producing rain, heavy at times, over parts of California and snow, heavy at times, over the higher elevations of California through Thursdays morning while beginning to wane.
Several tornadoes hit the Southeast Sunday afternoon, killing at least 22 people in one Alabama county on the USA's deadliest day for tornadoes in almost 6 years. As of late Sunday, there were 26 reports of tornadoes in the South, according to preliminary data from the Storm Prediction Center. Damaging tornadoes also hit Georgia on Sunday afternoon.. Powerful winds or a tornado destroyed several mobile homes in rural Talbotton 80 miles from Atlanta, said Ann Erenheim, director of the Talbot County Emergency Management Agency.
This is a quick storm, with precipitation occurring in a 12 hour timeframe, but it could have significant impacts on Monday. Once again, the uncertainty in track and location of any banding activity is leading to an unusually "unstable" forecast with "nowcasting" changes almost certain. Winds do not appear to be significant at the moment, with the wind threat being maximized the further east a location is. Behind the system, a Canadian high pressure system brings an Arctic airmass to settle in through the middle of the week, so any snow on the ground will be sticking around for quite a while.
WX Alert: Special Weather StatementWXD Alert: Post Discussion
Anywhere from 2-6 inches of snow on top of rain and sleet can be expected from the first system on Saturday. Heaviest amounts in the colder spots to the North and West of the coast. The second storm could be more widespread and have heavier amounts of snow with up to and over a foot in the hardest hit areas and a more general 4-6 inches elsewhere even along the SNE coast where mixing is also possible. A storm south of New England will move northeastward out over the Atlantic just missing New England on Saturday.
...Heavy rain forecast for the Northern California coast, with flooding possible... ...Multiple feet of snow expected in the Sierra Nevada...The western U.S. will continue to have active weather throughout the middle of the week, as an upper-level low spins off the Pacific Northwest coast and additional upper-level energy passes through on Tuesday night and Wednesday. Precipitation will fall as rain along the Northern California coast, and heavy rain is likely. A Slight Risk of excessive rainfall is in place on Tuesday and Tuesday night.