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Posted at 5:00 AM ET, 09/12/2009

Forecast: Gray Skies to Gradually Clear

By Jason Samenow

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Today: Mostly cloudy. Mid-70s. | Tonight: Clearing. 57-63. | Tomorrow: Partly to mostly sunny. 80-84. A Look Ahead | Get Express Forecast by E-mail


Over the past five days, other than for a few brief windows, the sun has not shined. All of that is about to change as the painstakingly stubborn coastal storm finally pulls away. In its wake, it will slowly but surely clear -- partially today and fully tomorrow. As the clearing occurs, temperatures will rise and I trust many spirits will soar...

Clouds: Latest mid-Atlantic infrared satellite loop, courtesy Unisys. Click here to expand. Refresh page to update. See more maps on our Weather Wall

Today (Saturday): We're not done with the clouds just yet. As the low winds down to our north and northeast, clouds will continue to pivot southward and even a stray shower (20% chance, mainly north of D.C.) is possible. By the afternoon, I think there's at least a 50% chance we'll have partial clearing which will help boost temperatures into the mid-70s, with upper 70s south of town. Confidence: Medium

Tonight: Confidence increases that clearing will accelerate. Sometime after midnight, perhaps stars will be viewable again. Overnight lows will range from the upper 50s in the cooler suburbs to the low-to-mid 60s downtown. Confidence: Medium-High

Keep reading for the forecast for tomorrow and into early next week...

Tomorrow (Sunday): Lots of sunshine. For real. High pressure will finally force out all of the gloominess and we'll enjoy blue skies and a warm late summer day. Highs should reach the low 80s, with a wind out of the north at around 10 mph. Confidence: Medium-High

Tomorrow Night: Expect a mostly clear and pleasant overnight with lows ranging from the mid-to-upper 50s in the cooler suburbs to the low 60s downtown. Confidence: Medium-High


Both Monday and Tuesday look pretty good. High pressure will remain in control with partly to mostly sunny skies and highs 80-85. Overnight lows should mostly be in the upper 50s to low 60s. Confidence: Medium-High

By Jason Samenow  | September 12, 2009; 5:00 AM ET
Categories:  Forecasts  
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Next: Forecast: Sunsational!


Last night MMCarhelp indicated that perhaps this storm should have been named as it had tropical system characteristics. Jason replied that he saw extratropical characteristics. Any chance someone could address the structure of this storm in more detail, based on the great discussion we had a year or so ago about what defined tropical vs. extratropical storms? I'm interested to know why this one could look like both.

Posted by: --sg | September 12, 2009 9:01 AM | Report abuse

I agree with Jason. The storm may have been warm-core or partially so during portions of its life but it had frontal structures as well. Yesterday, there was a pronounced warm frontal zone with it, which may have appeared to be a "feeder band". Much of the wind involved was gradient related thanks to the difference between high and low pressure, and as you got close to the center convection winds were weaker than on the periphery. That's fairly characteristic of an extratropical system. The NHC was monitoring it the whole week so I think they would have pulled the trigger if needed. Here's one of several threads discussing it on Eastern US Weather Forums.

Posted by: Ian-CapitalWeatherGang | September 12, 2009 9:25 AM | Report abuse

Hey, where's the UnitedCast? I need to know within 2 deg F what the kickoff temperature will be!

Posted by: JkR- | September 12, 2009 9:45 AM | Report abuse

Thanks, Ian! I read through the discussion thread you posted; this storm really seemed like a hard one to pinpoint. I saw last night where NHC had put the yellow area-of-interest indicator back over the storm, which made me wonder quite a bit. Regardless of why it wasn't named, this storm had a lot of impact over a wide area.

Hmmm - I'd better go drain the boat.

Posted by: --sg | September 12, 2009 11:20 AM | Report abuse

Major issue today is that the clouds keep hanging on...

Posted by: Bombo47jea | September 12, 2009 2:12 PM | Report abuse

Without a UnitedCast how am I to know what jersey to wear?

Posted by: rockotodd | September 12, 2009 2:16 PM | Report abuse

no united cast?

Posted by: mmsq | September 12, 2009 2:40 PM | Report abuse

Without the Unitedcast, I'll just guess and wear the Olsen jersey....

Posted by: JkR- | September 12, 2009 2:47 PM | Report abuse

I love this cloudy weather!

Posted by: Camden-CapitalWeatherGang | September 12, 2009 3:16 PM | Report abuse

Now let's talk about the wind. Today's NWS forecast had N winds 5-10mph dropping off in the evening. Around DC/NoVA, we've had sustained 10-15mph since about lunchtime, and DCA currently shows gusts to 21mph. This is consistent with an exiting storm - but I'm having trouble getting any guidance on how long the wind conditions will last. There's no posted Small Craft Advisory, mof there's no posted NWS Marine forecast at all right now (!), and CBOFS wind animations are offline due to technical issues.

OK, I'm whining - but I need some help figuring out what the winds might be like tomorrow on the upper tidal Potomac. My best guess is that these gusty winds will drop overnight, build back up early in the a.m., then drop like a rock around mid-day. What I really need are some nice smooth 8-12kt breezes tomorrow morning, for a make-up sail after a silly argument. CWG, do I have any chance?


Posted by: --sg | September 12, 2009 5:53 PM | Report abuse


Apologies for no UnitedCast today. It slipped through the cracks.


Should have winds from the north in the 8-10 mph range tomorrow, maybe gusting 5 mph or so higher.

Posted by: Jason-CapitalWeatherGang | September 12, 2009 11:03 PM | Report abuse

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