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north carolina

Winter Storm Threat: Feb 9-10 (final call)

The precipitation shield did fill in a little bit from DC and points south on the models, but not to the degree I thought they were going to. I made some adjustments to the forecasts because of that, bringing the 1-2″ line and the 2-4″ contour over the Apps. further south. I brought the 1-2″ contour up north in southeastern NC due to the warmer temperatures.

 
It will be hard to tell how much the DC area gets due to snow sublimation in the lower levels early on, but I could see DC/MoCo getting a dusting to 1/4″ with a small chance of going higher. Areas north of MoCo up towards Frederick and Baltimore could see a dusting at best.

Winter Storm Threat: Feb 9-10 (first call)

Another system with wintry precip. will move through the region late Wednesday through Thursday, and it yet another storm in an endless streak of high-difficulty forecasts. Most of the snow in this one will be isolated to the western Appalachians and to southern VA and NC, with accumulations of half and inch or less possible up to the Mason-Dixon line.

I weighted the NAM heavily again with this latest forecast, and I included some input from the ECMWF. I think the GFS is completely off in shutting down the precipitation once it gets south and east of the Apps, which is mostly due to the weakening of the upper-level vorticity that the GFS portrays. The NAM has been miles better in preserving the upper-level energy compared to the GFS, and it has been verifying noticeably better.

Here’s the first call for the event… a final map will be put up either late tomorrow or around noon on Wednesday.

 
Temperatures will be a bit of an issue as well, with rain and mixed precipitation in NC and VA to go with the snow.

Mid-Atlantic Discussion – November 30 – December 1

The SPC has been slowly creeping the Slight severe area northwards, as is no surprise. At this point, I think that the Slight will end up along the SE PA and through the northern parts of NJ going into Wednesday morning. SNE may also have a “See Text” threat past 14Z.

Anyway…

As we get closer to the zero hour, it’s become easier to decipher the model trends as far as where the warm front will be able to lift to and who is under the gun Tuesday night into Wednesday morning. The main area of concern will be NC/VA/SoMD where the dynamics and the warm sector can interact the most efficiently to produce severe weather in the form of a linear SSW-NNE line of storms along the cold front. The severe threat will extend up through the northern parts of the region, but as the SPC stated mid-level stability is more of a factor in areas north and west of the D.C. area, which means less reports and slightly weaker winds along with a lesser chance for tornadoes.

The GFS appears to have a better grasp on the timing, but the NAM’s instability parameters are much more favored due to the mesoscale nature of the event. However, as we saw with the severe event from two weeks ago, neither model had a true grasp on how unstable the LL air actually was. This could be attributable to the strong advection of low-level instability by the LL jet, which was likely mishandled and under-represented by the models.

All-in-all, I wouldn’t be surprised if this ended up being similar to our 11/16 event, with the severe reports shifted about 150-200 miles south. D.C. impact from the line of storms will likely be around 4-6 AM Wednesday morning.

 

Severe storms roll through the region

An unexpectedly-powerful squall line moved through the region between 11pm-2am last night, causing a good number of wind reports and a possible tornado near Baltimore, MD. The few people that I have discussed the Baltimore storm with who live in the area believe it was more likely straight-line winds or a micro-burst. Trees down across power lines and roads made the morning commute troublesome for some in VA and MD today.

Here is a link reporting on the possible Balitmore tornado: Severe storm damages dozens of homes in [Baltimore], Parkville area

As of 7am, more than 22,000 customers were without power in northern VA, MD and Delmarva, according to estimates totaled from four local and regional power companies.

More updates on the severe weather as reports and images/video come in.


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UPDATE: 1:00 PM ET

Damage pictures, via WBAL: http://www.wbaltv.com/slideshow/weather/25822631/detail.html

Videos, again via WBAL: http://www.wbaltv.com/r/25822434/detail.html
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UPDATE: 4:00 PM ET

From the Baltimore Sun: Photo Gallery of Baltimore damage

Mid-Atlantic Discussion – November 16

Looks like we’re in store for another high shear/low CAPE event later today and into tonight as a developing low pressure system swings its cold front through the region. Given the vast amount of pre-frontal precipitation and cloud cover, along with the timing of the storms, I will not be chasing today. My expectations will be to see a weak line of thunderstorms form along the cold front this evening, which will push into eastern VA, NC and southern MD/Delmarva in the early AM. A mesoscale discussion for this area will probably be put up in the evening, with a 30-50% chance of a TOR watch in the next 24 hours.

I won’t expect to see more than a half-dozen severe weather reports in the region today, with no more than 1-2 tornadoes. It’s another day of SPC hyping it up for the region.