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Posted at 04:43 PM ET, 06/29/2012

Gusty storms may momentarily break historic heat tonight; more brutal heat, storms this weekend

* Excessive heat warnings and heat advisories through 9 p.m. tonight | Excessive heat watch Saturday *

After the hottest June day in recorded Washington, D.C. history (104), the atmosphere is juiced for the possibility of strong-to-severe thunderstorms overnight. The weekend remains oppressively hot and humid, with likely additional rounds of late day thunderstorms - a few of which may be violent.

Through Tonight: A complex of thunderstorms with a history of producing damaging winds from Chicago to Fort Wayne, IN (91 mph gust) to Columbus, Oh (72 mph wind gust) is headed in the general direction of the metro region. It may lose some steam by the time it gets here - most likely between 10 p.m. and 2 a.m. and it’s possible it skirts us, passing just south. We’ll call for a 50 percent chance of storms, capable of producing damaging winds and/or hail. NOAA’s Storm Prediction Center indicates a slight risk of severe storms in our region, with a moderate risk to the west.

It’s very warm and muggy, with lows 72-80 suburbs-city, possibly slightly cooler than that if we catch the brunt of the storms. Record high minimum temperatures of 82 at Reagan National (DCA) and BWI (from 1991 and 1946) and 73 at Dulles (IAD, from 1991) cannot be ruled out.

Weekend temperatures: Both days are very hot and humid with more record-challenging temperatures possible. Highs are near the century mark, with heat indices of 100-110. Please take it easy this weekend. Overnight temperatures remain very warm, with lows only in the 70s to low 80s.

Record high temperatures Saturday are: DCA (100), IAD (98), BWI (100)
Record high temperatures Sunday are: DCA (102), IAD (94), BWI (103)
Record high minimum temperatures Sunday are: DCA (79), IAD (72), BWI (80)

Air quality will be unhealthy for sensitive groups (code orange)

Weekend thunderstorm risk: Significantly, a round of strong-severe thunderstorms is a strong possibility (50-60 percent chance) Saturday afternoon and evening (5-10 p.m. timing seems most likely right now) and a slight possibility (20-30 percent chance) late Sunday. Please stay tuned to this blog and/or Twitter and Facebook for updates.

See Camden Walker’s forecast into early next week. And if you haven’t already, join us on Facebook and follow us on Twitter. For related traffic news, check out Dr. Gridlock.

Historic to unprecendented heat in South: The D.C. area was not alone in establishing heat records today. The following cities broke all-time heat records: Columbia (108) and Nashville (109). Charlotte (104) and Raleigh (105) tied all-time record highs. Atlanta (104) fell one-degree short of its all-time record high and set a monthly record high. It is likely hundreds of daily and more than a few monthly records were also set.

By  |  04:43 PM ET, 06/29/2012

Categories:  Forecasts

 
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