Rocky stretch of severe weather starts today for Lower 48; tornado watch for S. Va., N.C.

The least active tornado season on record - one without a fatality – may well heat up some over the next few days.  Violent thunderstorms are forecast to erupt, producing damaging winds, large hail, and tornadoes.

The greatest risk of widespread severe weather is in the Plains over the weekend, but some dangerous storms could form in the Mid-Atlantic this afternoon: a tornado watch has been hoisted for southeast Virginia and eastern North Carolina through 9 p.m. tonight.

Tornado watch in effect through 9 p.m. today (NWS)

Tornado watch in effect through 9 p.m. today (NWS)

The watch area lies just south of Richmond, Va. and east of Charlotte, N.C.  It includes Raleigh, Norfolk and Cape Hatteras.  The National Weather Service Storm Prediction Center says there’s a high likelihood (70 percent chance) of at least two tornadoes, and a moderate (40 percent) chance of a strong tornado (EF2 or higher on the 0-5 EF scale) touching down:

THE ENVIRONMENT WILL FAVOR SUPERCELLS WITH A RISK FOR TORNADOES GIVEN THE INCREASE IN INSTABILITY AND VERTICAL WIND SHEAR THIS AFTERNOON…AND AN ISOLATED STRONG TORNADO OR TWO WILL BE POSSIBLE. OTHERWISE…DAMAGING WINDS AND HAIL CAN BE EXPECTED WITH THE STRONGER STORMS THROUGH THIS EVENING.

To the north of the watch zone, “general thunderstorms” are forecast from Richmond to Baltimore. Isolated severe storms could form, especially in central Virginia. A cold front slicing across the Mid-Atlantic is responsible for the expected round of showers and storms.

Beyond today, the attention turns to the Plains and Midwest where strengthening low pressure may trigger violent storms Saturday and Sunday. A large area of the southern and central Plains is in the slight risk zone for severe storms Saturday, including Ft. Worth, Oklahoma City, and Omaha. SPC warns large to very large hail is possible with “some increase in the tornado risk toward/just after sunset.”

(NWS)

(NWS)

On Sunday, the zone of risk expands and jogs slightly eastward, covering the southern and central Plains but also extending through Missouri and even into western Tennessee and Kentucky. Houston, Kansas City and Memphis are in the slight risk zone and a narrow pocket of moderate risk surrounds the intersection of Texas, Arkansas and Oklahoma.

(NWS)

(NWS)

SPC cautions the storm environment Sunday appears “quite conducive to supercells…capable of producing very large hail and strong tornadoes.”  Of the two weekend days, Sunday is likely the more active.

The risk of severe weather may persist into early next week from the South into the Tennessee Valley as the storm system slowly migrates eastward.

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