Thursday, January 28, 2010

Ready for 6 inches of partly cloudy?

11:30 PM FRIDAY 1-29-2010  Winter Weather Advisories for the Washington, DC metro area have been added to the giant swath of pink and blue stretching back to Oklahoma.  Since mid-afternoon, the 3-hour pressure tendency map has shown a significant decrease in surface air pressure across Mississippi and Tennessee. This observation among others led our team to hypothesize the "I-40" Kahuna will produce significant accumulating snowfall at least 50 miles farther north than what many were expecting. When you awaken to read this Saturday morning, you'll discover 4"+ of snow is on the menu for most of Maryland. Perhaps fortune will favor the bold.

ARRIVAL TIME: (calculated at 11PM by Forecaster Snowlover via short-wave tracking)
9:00 AM southern Maryland, central/northern Virginia;
11:00 AM BWI airport, central Maryland/Baltimore metro.

Our current projections selected cities from the Crossroads Center forecast project as confirmed by Stormcasters Friday afternoon 1/29. Parts of this report have been featured reported on 95.1 Shine FM (audio link to Wed 1-27 broadcast)

6.5 Salisbury, MD | 5.7 Washington, DC | 4.0 Baltimore, MD
13.0 Roanoake, VA | 11.0 Richmond, VA | 7.3 Charlottesville, VA
6.6 Raleigh, NC | 3.2 Charlotte, NC | 4.0 Spartanburg, SC
6.1 Memphis, TN | 2.5 Chattanooga, TN | 3.8 Little Rock, AR

TEAM REPORTS Lead stormcaster Ryan K. has an overview in the Winter Stormcast Zone The student collaborative team from the Crossroads Center of Baltimore County has produced this large-scale forecast stretching back to Oklahoma City. Several team members including Snowlover in Baltimore County and Forecaster Brisko in Greencastle, PA have assembled this overview

Our evening discussion centered on testing these hypotheses from today:
(1) Would the polar vortex veer east or northeast and permit a north trend?
(2) Could a weakness develop along east periphery of the Great Lakes high?
(3) Should the low then almost pivot along east side of the high?

STORM SYNOPSIS NWS Winter Storm Watches or Warnings continue to expand into areas not expecting to be in this game, including Missouri and Kentucky.  This indicates a northward trend in position of the surface low has developed. We hypothesize that a combination of strong upper level energy spinning across west Texas is enhancing “tropical forcing” of moisture from the Gulf of Mexico. This is driving moisture and heavy precipitation farther north than expected.

In addition, the North Atlantic Oscillation has not dropped much below neutral, and the Arctic Oscillation is not nearly as aggressive with it's decrease. These indicators could show that they are not as strong of an influence as the models once intialized, and as a result, the storm can come further north. We believe these factors are causing the precipitation shield to extend into the high pressure system and will bring accumulating snow possibly to the MD/PA border. Ready to get 6" of partly cloudy?


"Walking in Memphis..."
-signature song by artist March Cohn in his self-titled 1991 album

SYNOPSIS OF TEAM DISCUSSION from 11:00 PM THU 1-28:  Computer models have suggested the low will develop close to the Gulf of Mexico and travel on an east to northeast path towards South Carolina. This would not allow the snow to reach the Baltimore area. Current data shows 3-hour pressure falls are occuring in central Louisiana. If a surface low develops along the cold front any farther north than currently shown, the track of heaviest snow would begin shifting north as well. We believe the possibility remains for a general 1-3" snowfall in the Baltimore-Washington urban boundaries areas, with lesser amounts north and west of the cities. Higher amounts remain possible if the high pressure system does not intrude as much in the nextr 24 hours as models are projecting, and the polar vortex retreats even 15 or more miles to the north.
--Forecaster Snowlover

6:00 AM THURSDAY 1-28-2010 A major southern winter storm is developing across the Texas and Oklahoma panhandles today, tracking generally due east, impacting the Tennessee Valley Friday and reaching the Carolinas by Saturday morning. Given last computer model trends, it appears that walking in Memphis  from Friday into Saturday will be wintry. Walking in Annapolis, Maryland to Saturday's Polar Bear Plunge? You go right ahead there matey. With morning air temperatures around 20 F and light snow falling on waters hovering at 37 F. I hope fortune favors those bold, hardy folk.

PROJECTIONS FOR THE SOUTHERN BIG KAHUNA A Google Map of the impact region. Our Winter Stormcasters project the axis of heaviest snow to be along and south of a line from the Virginia Tidewaters west and southwest through Asheville, NC line to Nashville, TN into Tulsa, OK. Texas and New Mexico will also get significant snow. Areas shown in pink on the National Weather Service Watch/Warning Map expect to receive 6 to 12 inches, but places like Memphis are in line for more of a wintry mix with sleet, freezing rain and snow totaling up to 3 inches.

BUT WHAT ABOUT THE MID-ATLANTIC? With many areas already at or above their seasonal snowfall thus far, we will have to remain patient for a fantastic February. As discussed on Baltimore's 95.1 Shine FM yesterday, it's a one-in-a-million situation. This time, Head Coach Snow Miser traded for a strong new Polar Vortex pitcher right before the opening ball toss, and he's going to do what owner Mother Nature wants. This strong upper level vortex is abnormally located just above the Great Lakes, a driving factor in keeping much of a potentially historic snowstorm south of the DC-Baltimore metro region. Other times, storms of this type have trended farther north. As Captain James T. Kirk would say with a smile, "Not this time."  (Mr. Foot"note" -- there's still a chance.)

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