Friday, September 7, 2012

Stormy Day Ahead 

NOAA Day 1 Severe Weather Outlook


Current SPC Day 1 Outlook showing moderate risk of damaging winds

8:20 AM EDT 9/8 (Severe Weather Team) Widespread severe weather has been kept at bay for the past couple weeks in this region. However, that may change on Saturday. A powerful cold front and associated upper level trough will blast through the Mid-Atlantic by Saturday evening. Plenty of wind shear is available for organized strong to severe thunderstorms. The NOAA Storm Prediction Center has a MODERATE RISK for severe weather over the northern Mid Atlantic, although the threat will extend across the entire region.
  • HAZARDS: The most intense storms would be capable of producing destructive winds over 65 mph, isolated tornadoes, and large hail around one inch in diameter.
  • TIMING: Current indications are that a squall line will form off the mountains by 3-4PM, and will track rapidly eastward across the D.C./Baltimore/Philadelphia metropolitan areas over the ensuing 2-4 hours. The line would reach the Atlantic beaches between 7-10PM.
One limiting factor for a widespread outbreak may be morning cloud cover early in the day. But otherwise conditions appear favorable for a notable region-wide severe thunderstorm event. (Forecasters Jason M, Josh O, and the Severe weather team)

Stormy Sign Of Things To Come

4:00 PM CDT 9/7/12  (Severe Weather Forecaster Wesley Hicks) A wide swath of Severe Thunderstorm Watches are in effect across the Ohio Valley and Mid-Mississippi River Valley as a line of significant storms is developing along a rapidly moving cold front. 

  • Widely scattered storms will continue to develop and track eastward across this afternoon. The environment is moderately unstable and supportive of Severe Weather. The best shear is located behind the front which is a limiting factor for a more widespread/significant threat. 
  • Damaging winds may be the primary hazard with the strongest cells, followed by Large Hail. The Tornado threat will remain low. Keep an eye on the latest watches and warnings if you live in or near the areas denoted in the SPC graphic.

Among the Severe Thunderstorm Watches is # 630 is in effect until 10:00 PM CDT for Northeast Oklahoma...Southeast Kansas...far Northwest Arkansas..and much of Southwest and Central Missouri. This includes the cities of Tulsa, Joplin, Springfield, and Fayetteville.

Mid-Atlantic Risks For Saturday: In addition to near-term impacts as noted above, a large portion of the Northeast also faces a moderate risk of damaging winds from any severe thunderstorms that develop along the eastward progressing cold front. View the most current Day 2 Outlook issued as of 1:26 PM EDT Friday 9/7/12.

Current forecast decision graphic from the Severe Weather Team
Image credit: NOAA SPC and Forecaster Josh Owens.

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