Wednesday, February 3, 2010

"This time I know it's for real..."
- Artist Donna Summer, in the 1989 single by the same title

11:45 PM TUESDAY 2.2.2010  If you are a fan of pop 80's music, then this fun upbeat song hits it on the head in so many ways for this week's snow events, I will let you interpret the meanings behind Ms. Summer's lyrics. -Forecaster Foot

THE GROUNDHOG APPETIZER Heavy snow is being reported across northern Virginia into central Maryland and along the I-95 corridor, a little later than we expected as originally stated this morning (9am Blue Ridge/12 noon I-95). Snow will continue and increase in intensity overnight. (Previous details removed for clarity)


If computer model trends continue as they have in the past 24 hours, this storm has potential to eclipse December 19, 2009 ; February 15-18, 2003 ; January 6-8, 1996 ; March 11, 1993 ; February 11, 1983 ; December 1966, and could rival March 18-22, 1958. We are are not trying to be sophomoric for the sake of ratings. 

In this highly charged El-Nino pattern, with the 3-month Oceanic Nino Index (ONI) equal to January 2003, this weekend's storm may represent what February 2010 could deliver, and bear similarities to January 1994 along the eastern seaboard.

SUPPORTING DATA PROJECTIONS Forecaster Brisko of Penn State University recently issued the latest liquid equivalents from both the European (ECMWF) and US Global Forecast System (GFS) computer models. We have been examining this potential for 36 hours, and this constitutes our "FirstCast" but by no means is a "Storm Grade Amount" which is customarily released 12-24 hours before the event.

Projected liquid equivalents 
Washington to Richmond 1.75 - 2.00"
Baltimore to Philadelphia 1.50 - 1.75" 
Harrisburg to Hagerstown 1.25 - 1.50"

Possible snow ratios 
The three most recent storms have produced ratios 2 or 3 inches higher than what our forecast team has projected (14:1 for Dec 19, actual 16.7 ; 12:1 for January 8, actual 14:1 ; 15:1 for January 30, actual >20:1). Based on this, the team and students are setting 16:1 as a general baseline snow ratio for this event.

FIRSTCAST & RATIONALE  Using 16:1 as a guide, 1.50" as liquid midpoint, our early and unofficial projections for the Baltimore-Washington-Philadelphia metro:
LOW: 12-18" (if sleet or rain mixes in midday Saturday)
MEDIUM: 20" (if less mixing and primarily snow)
HIGH: 24"+   (if higher ratios/new snow cover holds temps down)

Has this happened before?  While many may view this as hypecasting, storms of this magnitude crippled the Northeast megalopolis twice in 1958: January 13-16 and March 18-22. Areas of Frederick County, MD and Chester County, PA received 44 inches, while Baltimore County saw 28 to 30 inches. It has happened before, it will happen again, it's just a question of when.

Analysis of bust potential  A history lesson is embedded in this forecast, that of March 4-6, 2001. Some of you may remember this most collosal bust in the history of modern forecasting: 24 to 36" was predicted for the Northeast corridor. Everyone was on board, from HPC to Accuweather to TV forecasters, and yes even Mr. Foot. The storm did materialize, but heavy snow occured in northern New England. The I-95 corridor? About an inch. Are we setting up for another collosal bust? You can be your forecast team will be watching THAT potential very closely, but the arrange this time is very different. Being that it is early February and not March, climatology favors the bold. Want to learn more about past storms?  Look over this site of past winter storm animations and be amazed.

SO THIS TIME IT'S FOR REAL? With the North Atlantic Oscillation not showing a sharp negative trend to suppress the storm, and several Canadian high pressure cells at the ready, we might be looking at game, set, match.  Obviously we will defer to NOAA's HPC for federal guidance on the precise language on storm evolution. Students whom have spent hours of their own free time examining this strongly encourage county officials, superintendents, school administrators and emergency management officials to investigate the data and consider the impacts this storm could create.

Hazardous Weather Outlooks are already hoisted by many of your local National Weather Service offices in Mount Holly, NJ ; Sterling, VA and Wakefield, VA

Mother Nature is showing her cards early, are the right players at the table ready?

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