Friday, February 17, 2012

Can't Hardly Wait
-  title of 1998 teen comedy

5:15 AM EST 2/17/2011 On this important Happy Friday of President's Weekend, we know may readers have major plans for travel, touring or relaxation in the days ahead. Others in emergency management or facilities management are having their plans turned upside down by the potential of a holiday weekend snowstorm. For students and teachers in the Mid-Atlantic, "just getting one day off" is something or which we know you can't hardly wait. 

Our Winter Stormcast Team continues to see the potential for a significant winter storm to strike the Mid-Atlantic region late this President’s Day weekend. However, we do not believe this storm will rank alongside previous high-impact events associated with this uniquely frequent weekend of snow events from the past. Thus, "#PDIII-jr" is the new moniker assigned to this storm by our team. 

With many readers seek as much information on the storm as possible, we offer this assessment following our multi-state collaboration last night:

  • Development: Computer models are showing the two jet streams across the country combining together Saturday night to produce a deepening storm system for Sunday. 
  • Track: Low pressure is expected to track from the Southeast U.S. to the Mid Atlantic coast during the day Sunday.
  • Timing: Computer models are now delaying the precipitation onset until early to mid Sunday morning, and exiting the region Sunday night.
  • Precipitation: The storm should begin for most regions as rain from Virginia on south, with an area of snow to the north. Given that surface temperatures will be near to above freezing, rain may mix with snow for a period on Sunday, before changing to all snow. 
ACCUMULATIONS & ANALYSES We will be issuing preliminary ideas on snowfall amounts later today, with Storm Grade Amounts on Saturday for selected locations. Our Meteorologist Advisors have posted two discussions in the Winter Stormcast Zone for your review which detail a few key points from their analyses of the storm situation as of Thursday afternoon. 

(Lead Forecaster Jason M., Winter Stormcast Team; Advisors Foot, Berk Winstead)

Thursday, February 16, 2012

Joining forces 
Atmospheric pattern and model projections pointing 
to a Mid-Atlantic Winter Storm Sunday into Monday

5:10 PM EST 2/16/12  We offer this composite overview map of snowfall potential for the #PDIII snow event this weekend in the Mid-Atlantic. Note that we have not established snowfall amounts, but for now are focusing on liquid equivalents until the event gets closer.

  • Preliminary: This is a preliminary estimate of areas where we believe snowfall may accumulate in the late Saturday to early Monday period (2/18-20/2012). 
  • Map Colors: Bright white on this map represents where we believe the best chance for "plowable snowfall" may occur. The grey color on this map indicates more of "nuisance" snowfall which may still require removal.
  • Amounts: Snowfall ranges and specific amounts are generated once onset of snow in the region is within 48 hours. 
  • Timing: We will issue an updated version with a timeline this evening.
Credit for this map goes to Forecaster Jason Warren of our Ohio Valley Winter Stormcast page, which you can view on Facebook. Additional details will be posted in the main site Winter Stormcast tab as we approach the evening.

12:30 PM EST 2/16/12 Latest model runs have indicated more consensus is developing in the project data for a potential President's Day weekend storm. The GFS model (mid-range model) and the NAM (short range model) have both painted a very similar solution which is an increasing wintry scenario for the Mid-Atlantic states. 

NOAA model projection for 8 AM Sunday morning shows low pressure moving through the Carolinas, with the  5,000 foot freezing line parallel with I-68. Liquid amounts from GFS suggest about an inch of liquid could fall, but the big question is how much of that liquid falls as rain and how much falls as frozen precipitation.

Additional details on this developing situation for the region are posted in the Winter Stormcast Zone.   (Forecaster Greg J. and the Foot's Forecast Winter Storm Team)
"The status quo has changed."
-Patrick Gates, played by Jon Voight in National Treasure (Trailer)

Photo credit: Baltimore Sun Maryland Weather Blog
showing a fine day in Charm City, February 2003.
12:05 PM EST 2/16/12 | For those tracking developments in latest computer model trends for the Mid-Atlantic weekend snow threat, the most recent projections continue to point towards a significant event Sunday into Monday. NOAA Meteorologists and our team have both been examining recent outputs from the Global Forecast System, monitoring climate teleconnections and other data to identify early signals in this storm system. Our team is posting a new statement in the Mid-Atlantic Winter Stormcast Zone momentarily. 

  • Liquid equivalent: Preliminary ideas to be posted in this evening's update;
  • Timing & scenarios: In tonight's statement, we may begin narrowing the scenarios to a "Hypothesis A vs. B" 
Our preliminary snowfall ideas are generally posted around the 72 hour mark. Given that the regions at risk in the Mid-Atlantic are outside 72 hours until onset of snow, we issue more information after full set of land-based NWS stations have generated observations about the upper level systems in play.

The acronym "PD III" suggests that if this storm were to become as significant as some computer models are indicating, it might earn a place in the historical record as a distant cousin to President's Day storms of the past: 
  • PD I was the famous storm of February 18-19, 1979
  • PD II is the more recent storm of February 15-18, 2003. 
This article by the Baltimore Sun's Maryland Weather Blog takes you back to the fond memories ... strained backs and stranded cars... that are part of February climatology in the Mid-Atlantic.

Continue checking this page and our Winter Stormcast Zone, which is also on Facebook for the Mid-Atlantic, for the latest ideas later this morning. We provide our readers with a "wide-angle" view on analyses from certified, broadcast and degreed meteorologists and forecasters across 20 states, collaborating on latest observations and computer model outputs. (Photo credit: Carroll County Times picture of Forecaster Greg Jackson in a September 2011 article) 

If you're interested in joining our team, please visit our "Opportunities" tab on this site.

(Forecasters Foot, Greg J. Matt Balash, Coordinator Dakota S. and Meteorologist Justin Berk)