Update 5:11 p.m. Friday - There is now a tornado warning in southeastern Fairfax County until 5:45 p.m. and a severe thunderstorm warning in southern Fairfax County until 5:30 p.m.

If you are inside a building, please go to an interior room on the lowest level — rooms without windows are safest.  Stay off the roads if you can unti after this line of storms passes.

Update 4:45 p.m. Friday: A severe thunderstorm warning is in effect for Alexandria South and southeast Fairfax County until 5:15 p.m. as heavy rains, thunder and lightning move through the area.

The D.C. metro area is under a flash flood watch until midnight.

Doppler radar at 4:40 p.m. showed strong thunderstorms over Arlington, Alexandria and southeastern Fairfax County, with rain continuing west to Front Royal. Another line of storms is located west of Interstate 81.

To clarify, a "watch" means conditions are favorable for a certain type of weather, but a "warning" means weather is happening or is about to happen.

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Update 3 p.m. Friday: Many parts of Northern Virginia are now under a severe thunderstorm warning. "National Weather Service doppler radar indicated a severe thunderstorm capable of producing damaging winds in excess of 60 mph," according to a Fairfax County emergency alert. At about 3 p.m., the storm was located just north of Dale City and moving northeast at 30 mph.

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Update 2:30 p.m. Friday: The National Weather Service has issued a tornado watch across Northern Virginia until 9 p.m. There is now a tornado warning in Loudoun County and in Mongomery County, Md. until 2:45 p.m.

Winds are starting to pick up and scattered rain is developing across Northern Virginia ahead of the cold front that will bring strong thunderstorms to the area during rush hour.

Tips on driving safely in inclement weather are below, and also review tips on what to do in the event of a tornado.

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Update 6 a.m. Friday: Isolated thunderstorms may start popping up in the early afternoon Friday ahead of a cold front with stronger and more widespread thunderstorms.

Thunderstorms are expected to increase right before rush hour this evening with the strongest storms predicted from 7-9 p.m.

High temperatures on Friday will be in the low 80s.

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Weekend Starts with Strong Storms

Original Post - Thursday, May 31

Weather forecasters in Northern Virginia are casting a wary eye toward the west, where severe thunderstorms are developing ahead of a cold front. Those storms could hit Northern Virginia around 5 p.m. Friday and have a significant impact on the evening commute.

“There may be a couple waves of storms affecting the region through midnight or so with heavy rain, gusty winds and dangerous lightning. Some storms may contain damaging winds and large hail with the outside chance of isolated tornadoes,” Capital Weather Gang’s Jason Samenow predicted Thursday.

Friday will start out cool and partly cloudy, with temperatures in the upper 60s around sunrise.  Temperatures will rise into the low 80s with an increasing threat of scattered thunderstorms throughout the day before the evening storms roll into the area.

While driving tomorrow evening, remember these tips for driving during severe weather from The Weather Channel:

• Turn on your lights (low beams) and leave plenty of distance for braking.
• If you do not feel safe driving or visibility gets too low, pull over and off the road to a safe location and wait for the rain to subside.
• In a lightning storm, your car generally is a safer place to be than outside.
• If the power is out at an intersection, treat it as a four-way stop.
• Do not drive through large puddles – your car may stall or flood.

Friday is the first day of meteorological summer and the first day of the 2012 hurricane season, which may be “near normal” according to some forecasters.

Temperatures will rise only into the 70s on Saturday as skies clear.

The Capital Weather Gang is predicting a slightly warmer-than-average June in the D.C. metro area despite a cool start.