CATEGORY 4 SEVERE STORMS
1. A few tornadoes
2. Wind damage, gusts over 70 mph
3. Hail up to 1.5 inches
I am very impressed with an outbreak of severe as outlined on the map below. The initial run of storms will develop across West Virginia and move quickly east-northeast with wind damage, potential tornadoes and hail. The shear values across south-central Pennsylvania are very high and can support the potential for tornadoes. After the first few hours of storms and tornado potential, we should see a linear squall line develop from Harrisburg to south-central Virginia that will move through southeast Pennsylvania, Maryland and Virginia impacting Baltimore, Washington and Philly with high winds and heavy rain. I expect to see about 10-20 reports of tornadoes and over 100 reports of wind damage.
The tornado threat will last from 2 p.m. to 7 p.m. for areas bounded by State College, Du Bois, Johnstown to Roanoke to Hagerstown and Harrisburg to State College. Within that area, shear values are high and RR model suggest that discreet storms will have rotation within them.
The dynamics are very impressive with a 100 kt jet nosing into the threat area, a deepening low pressure going to 996 mb, a 50 kt 850 mb jet, surface dew points coming up into the mid-upper 60s. Model soundings show high helicity and turning of the winds with height.
So all the parameters are coming together for a major outbreak in the part of the country that does not really see outbreaks like this.
I will be twittering information out during the day and evening. You can follow me at http://twitter.com/#!/Henry_Margusity
Storms will continue to roam along the front today. Some of the storms will become severe. More storms will hit the Upper Midwest Sunday.
The pattern will produce heavy thunderstorms each day as trhe trough remains in the eastern part of the country.
Storms will develop under the trough today, Some of the storms will be heavy at times with gusty winds and hail
Severe storms with damaging winds and hail will hit parts of the Ohio Valley today. The heat wave continues this week in the West.
An unusual storm will bring severe weather today and signifcant flooding potential for Saturday.
Active through this weekend with severe weather and heavy rains. Floodin may become an issue by Saturday.