Browse Month

November 2010

What to Watch Fore(cast) – Nov 22-28

Highlights:

Severe risk in the Midwest – Ongoing storms continue to produce severe weather tonight, but another threat for severe weather will come mid-week.

Wet Thanksgiving in the East – Much of the East Coast will have cloudy skies and rain (with some snow further north at night) this Thursday.

Very cold in the West – The western half of the country will be stuck with much below normal temperatures through the work week.

New pattern setting up? – Models are suggesting a change in the pattern as things evolve this week and next week.

—–
Discussion:

Low pressure systems have been struggling to push into the Southeast due to a recurring ridge of high pressure over the Southeast, which has caused the lows to lift northward before reaching the Appalachians and the East Coast. This scenario will likely get played out for the next few systems that roll through the country (including today’s system and tomorrow’s developing systems). This storm track will allow for severe weather to occur along the systems’ cold fronts, which would give the U.S. a nice boost to the overall severe wind/hail/tornado counts before the end of the year.

This pattern may be consistent through at least the first week of December or until we do end up seeing that first real push of much below normal temperatures along the Eastern third of the country. With the models coming up with a different long-range solution every day, it will be hard to determine exactly when until it’s but a scant five days out.

The system developing in the mid-country tonight and into tomorrow will be a big rainmaker in the East on Thursday, meaning a lot of us will be out playing football in the mud instead of a dry field. It will be a good day to stay inside and enjoy family, friends, food and football in front of a cozy fireplace. After that, we’ll see a cool-down with lake effect rain and snow possible off of the Great Lakes through Saturday. Areas W/WSW of the Lakes could see some good snowfall totals out of this week.

A persistent upper-level trough over the West will keep things rather cold there this week. 1-3 additional feet of snow could get added to the mountains in the Pacific Northwest. Seattle could even see a little more accumulation to go with the 2 inches of snow they already got this week!

Mid-Atlantic – The Week Ahead (Nov 21-28)

Temperatures will be on the rise today and tomorrow, with widespread upper 60s and a shot at 70F possible on Tuesday. Recent model runs have indicated that the region may not get as cold as was previously forecasted, but we will see if it doesn’t get pushed back into the forecast. After running so cold for so long a dramatic change like this (closer to normal than sitting in the below normal range like it was), it’s hard to fathom NOT getting colder temperatures this upcoming weekend.

We’ll be in a bit of a disturbed weather pattern this week, starting with a cold front moving through on Tuesday, which will bring non-exciting rain and maybe an embedded thunderstorm. Wednesday will be dry, but another system developing over the Plains will move into the region on Thanksgiving and into Friday, which will cause widespread wet weather. Saturday should be dry but windy, with conditions improving to mostly sunny skies by Sunday.

Baltimore damage confirmed as macroburst and tornado

The NWS survey team has concluded that the extreme damage in the Baltimore area on Tuesday night was the result of a macroburst and an EF-1 tornado.

NWS Survey

From the NWS survey:

THE PATH OF WIND DAMAGE FROM THE THUNDERSTORMS THAT ALSO
PRODUCED THE BRIEF TORNADO STARTED ON THE WESTERN EDGE OF
MORGAN STATE UNIVERSITY IN NORTHEAST BALTIMORE CITY AND THEN
CONTINUED FOR APPROXIMATELY 5 MILES TO THE NORTHEAST TO
GUNPOWDER STATE PARK IN BALTIMORE COUNTY. IT SHOULD BE NOTED THAT
THE VAST MAJORITY OF WIND DAMAGE ALONG THE 5 MILE LONG PATH WAS DUE
TO STRAIGHT LINE WINDS FROM THE DESCENDING REAR-INFLOW JET AS IT HIT
THE GROUND…REFERRED TO AS A MACROBURST. EMBEDDED WITHIN THE DAMAGE
PATH OF THIS MACROBURST WERE TWO AREAS OF DAMAGE THAT ARE ASSOCIATED
WITH THE EF-1 TORNADO.

Basically, the damage was an isolated event wherein a localized strong burst of wind descended from the storm and slammed into the ground. This burst of wind also increased rotation in the atmosphere, which led to the formation of a brief EF-1 tornado.

Here are the Base velocity (left) and SRM velocity (right) scans of the line of storms as the tornado was reported to be on the ground. The image is courtesy of KMUWx91 from the American Weather Forums. On the right image, red pixels indicate wind going away from the radar, and green pixels are winds going towards the radar. This image indicates that there is some weak cyclonic rotation with the storm, which is a sign that there could be a tornado.

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.


_____
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
_____
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.

What to Watch Fore(cast) – Nov 15-21

Highlights:

Early soaker in the East – A low pressure system will bring widespread rain to the eastern third of the nation today through Wednesday.

Lots of snow for the Pac. Northwest – A couple of low pressure systems will draw cool air into the Pac. NW and the mountains will see significant amounts of snow.

Warm again in the East this weekend – Another mostly sunny and warmer than normal weekend is expected along the East Coast.

—–
Discussion:

A low pressure system that is currently over the southeast and southern Midwest will push north over the next couple of days, resulting in widespread rainfall for the eastern third of the nation. Some isolated severe weather will be possible tonight and tomorrow, but should not be anything significant. Widespread rainfall of 0.5-1.0+ inches will work up through the East Coast through Wednesday night. Following this system, a weak disturbance will bring isolated rain and show showers into the Midwest and Mid-Atlantic Wednesday night through Thursday night as it pushes eastwards towards the Mid-Atlantic Coast. The snow should stay north of the Mason-Dixon, except in areas of higher elevation.

A pair of disturbances moving over the Pacific Northwest this week will pack a punch as cold air seeps down from Canada, providing cool enough temperatures for big snowfall. The Pac. NW mountains could receive 1.5-3 feet of snow this week.

As the pattern calms over the eastern half of the nation, a subtropical ridge of high pressure will sit over the Southeast this weekend, providing the eastern half of the region with slightly above normal temperatures and mostly sunny skies. It should be another mild and pleasant weekend for the East.