D.C. area forecast: A sweaty day with serious storm potential

* Flash flood watch through this evening *


Radar & lightning:Latest regional radar shows movement of precipitation and lightning strikes over past two hours. Refresh page to update. Click here or on image to enlarge. Or see radar bigger on our Weather Wall.

10:00 a.m. update: The severe thunderstorm watch has been canceled for the area as storms are now exiting. Intense storms are still possible this afternoon and new watches may be issued. We will have a new blog post with our thoughts on the afternoon potential by around 11 a.m.

9:45 a.m. update: Storms from the District and points west are falling apart and/or exiting. There’s still a tail of some stronger storms dragging through southern Maryland (southern Anne Arundel, southeast Prince George’s, northeast Charles, and northern Calvert counties) that will rapidly shift towards the Bay in the next 30 minutes.

9:28 a.m. update: Severe thunderstorm warning for extreme eastern Prince George’ County and much of Anne Arundel County through 10:15 a.m. for possible wind gusts to 60+ mph and hail.  Nasty storm currently moving into Annapolis.

9:25 a.m. update: Storms are now into D.C. and some heavy downpours stretch back to the western side of the beltway and are rapidly headed east.  To the northeast, strong to severe storms stretch from the Baltimore Harbor back through central Prince George’s County, headed in the general direction of Annapolis in the next 20 minutes or so.

9:08 a.m. update:  Ominous skies are everywhere and the storms are now moving into the northwest side of the beltway and should zip across the District in the next half hour.    Despite the scary looking clouds, storms are generally not severe, a notable exception being the storm in eastern Howard county headed into Baltimore which has a new warning in effect until 9:45 p.m. for hail and winds to 60+ mph.

8:48 a.m. update: Storms are headed down the I-270 corridor in Montgomery county and knocking on the door of western Fairfax county. (Again we expect them inside the beltway in the 9:15-9:30 a.m. range). These are strong, but not severe at the moment.  The most intense storms continue to be in northern Maryland; severe thunderstorm warnings are in effect north of Baltimore.  In addition to the hail in Frederick County earlier, some reports of downed trees have come in from Woodsboro.

8:40 a.m. update: Some good news – line of storms appears to be weakening as it enters the immediate metro region.  Still, expect some gusty winds and heavy rain.  There are not severe thunderstorm warnings in effect for the immediate D.C. area at the moment.

8:30 a.m. update: Line of storms continues steady march towards immediate metro area.  It is strongest in northern Maryland. Half-dollar sized hail was reported in Frederick, and ping pong ball sized hail in Carroll county.  Storms are now moving into the Leesburg area and western Montgomery county. Still thinking these move inside the beltway in about an hour.

Image: Reader photo of ping pong to golfball size hail in Frederick County (via Facebook)

8:05 a.m. update: The line of storms has strengthened somewhat as it has emerged from the mountains and is now slamming (or about to slam) northern Fauquier, western Loudoun and Frederick counties. Strong winds to 60 mph, torrential rain, and hail are possible in these storms and severe thunderstorm warnings have been issued through 8:30 to 8:45 a.m. These storms will reach eastern Loudoun (Leesburg to Sterling) and western Montgomery county around 8:45 a.m., and will move inside the Beltway around 9:15-9:30 a.m. You may want to alter your commuting schedule a bit to avoid these storms.

7:10 a.m. update: Line of fast-moving storms – that originated in Iowa and Illinois last night – now entering eastern West Virginia. These storms should move through the D.C. area between 8 and 10 a.m., first hitting Loudoun/Frederick counties (8-8:30 a.m.), moving inside the beltway around 9 a.m. and then exiting counties adjacent to the Bay around 10 a.m. (these are estimates, may change). Storms should have briefly heavy rain, lightning and gusty winds. Widespread damaging winds are not expected. Most of the wind gusts with these storms should be in the 30-45 mph range, although isolated higher gusts are possible and it wouldn’t be surprising to see some severe thunderstorm warnings issued.

Today’s Daily Digit

A somewhat subjective rating of the days weather, on a scale of 1 to 10.

1
Heat, humidity, potential high winds and heavy downpours – all start with H. Hmm, reminds me of another H word!

Express Forecast

Today: Variably cloudy, thunderstorms likely, some severe. Highs: 88-93.

Tonight: Thunderstorms exit, strong winds persist. Lows: 58-63.

Tomorrow: Partly cloudy, few p.m. showers. Highs: 77-81.

FORECAST IN DETAIL

storm threat

Hopefully today’s storms don’t live up to their potential, but with an elevated severe weather threat in the region, caution is key. Flooding rain and damaging winds are possibilities. In any event, it will be a good day to stay inside with all the humidity. The payoff is a perfectly lovely weekend with mainly clear skies and much more seasonable readings and, best of all, much drier weather.

Today (Thursday): Morning thunderstorms are likely (most likely timing 7-10 a.m., first hitting western areas), leftovers from the overnight complex that tore through the Ohio Valley (link: regional radar).  These may produce torrential rain (flash flooding possible), strong wind gusts, hail, and even a brief, isolated tornado for the a.m. commute, hence this morning’s severe thunderstorm watch. To complicate things, after these exit and/or break apart, partial clearing may allow heating that could fuel the eruption of more storms as soon as late morning into early afternoon.  Then, as an unusually strong cold front (for June) approaches later in the afternoon, another round of storms is likely to charge into the region (70% chance).

Storms, particularly those in the afternoon, may produce flooding rain, damaging winds, hail, and even isolated tornadoes.  The National Weather Service Storm Prediction Center places the region in a relatively rare “moderate risk” zone for severe weather.

Winds coming from the south at 10-20 mph shift to northwest by late day with gusts to 35 mph (note: wind gusts may be much stronger in severe thunderstorms, exceeding 50 mph). Highs reach the upper 80s to low 90s in most areas. Confidence: Medium

Tonight: A few showers could linger into the early evening (40% chance) but with much milder and drier air muscling into the area they should die out quickly. Hold on to your hats as winds remain a factor, coming from the northwest at 15-25 mph. The upshot of the blustery winds is cooler, drier air with lows dropping into the upper 50s to lower 60s.  Confidence: Medium

For related traffic news, check out Dr. Gridlock. Keep reading for the forecast through the weekend…

Tomorrow (Friday): Skies should be clear enough to start the day to allow us to witness the earliest sunrise of the year. Winds remain brisk coming out of the northwest at 10-15 mph. The air overhead is going to be so cool that even with highs only in the upper 70s to lower 80s and moderate humidity, some clouds pop-up. There is even a 40% chance of getting a light shower out of the more vigorous ones and a few wind gusts up to 30 mph. Confidence: Medium

Tomorrow night: Clouds disappear by sunset, winds start to subside and dry air is in place with evening readings in the 70s. What a perfect start to the weekend! Lows fall to the mid-upper 50s in the burbs and near 60 downtown. Confidence: Medium-High

A LOOK AHEAD

Saturday is a winner. With the sun nearly overhead that translates into a quick warm up. Highs in the low-to-mid 80s should be plenty enough to please pool and beach goers and with relatively low humidity should not push any of us too hard. Confidence: Medium-High

Sunday awakens to morning lows in the low-to-mid 60s. A little more humidity sneaks in but nothing too remarkable as we should all be summer-hardy by now. Highs may stall in the mid-80s as clouds are likely to increase in the area as the afternoon progresses. If they fail, some upper 80s are possible. If instead, the system is faster, they could kick off some late afternoon showers (20% chance). Showers are more likely to scatter through the area later in the evening (60% chance). Overnight lows only slip to the mid-to-upper 60s. Confidence: Low-Medium

Back to work Monday looks like it could be a potentially showery day but don’t let it get you down. At least for now, they look gentle. Chances are 60% for getting wet. Highs should be mid-80s. Confidence: Low-Medium

Also on Capital Weather Gang

Update: Tracking multiple rounds of dangerous storms tonight and Thursday