ORIGINAL ANALYSIS FROM 9:45 AM.
(1) Moisture from the stalling frontal boundary is over-running a 1040 mb High pressure at all critically analyzed levels of the atmosphere: 500mb, 700mb and 850mb. Embedded in the southwest to northeast flow are several shortwaves to cross the Mid-Atlantic overnight.
(2) Rules of climatology are not ruling the day as temps will remain nearly 10 degrees below normal. While the atmosphere over the metro areas remains dry from surface to 12,000 feet even the NWS admits rapid influx of moisture aloft in this cold regime will saturate the air. Relying on guidance and climate norms, without taking into account the trend in plain sight will make for a lot of surprised people Friday morning.
3) Latest NWS update states 1-2" of accumulating snow (or sleet/freezing rain) overnight in the following MD/VA counties: Charles, St. Mary's, Montgomery, Prince Georges, Loudon and even DC means there is a surprise risk of those schools being delayed on Friday. While the ground may be warm, remember this snow will fall at the point when temps are lowest overnight.
WHAT'S REALLY AT THE END OF THIS RAINBOW? If the current trend is any indication, forecasts regarding this snow/ice event across the Tennessee Valley are not going as planned. Just atake a look at the Water Vapor loop and be stunned at the moisture influx. I think we have a serious problem developing for the Mid-Atlantic that sneaking up on everyone right before their eyes. DID YOU CLICK ON THAT FIRST LINK OR JUST PASS OVER IT?
SYNOPSIS: WED MAR 11 - 9:45 AM. Teachers, students and coaches alike are no doubt rejoicing in the return of mild Spring-like weather, albeit sporadic. What a difference one week makes! This time last week many in the school community were still basking in the glow of a extended weeked. The see-saw warm to cold back to warm reminds us all that March is a volatile month, and the whipsawing looks to continue into next week. Here's a breakdown of the trends going forward for the Mid-Atlantic region:
WED TO THU: A vigorous cold front passes, and Wednesday afternoon temps might make a brief run towards 65 F along the I-95 corridor. Tonight, scattered light showers will be followed by winds shifting to the northwest. Much colder overnight into tomorrow, with lows nearing 32 and daytime highs holding at or under 45.
FRIDAY: Cold Canadian high pressure settles in behind the front, with highs not cracking 45. A stark difference from last week's 5-7 day forecasts for highs late this week in the mid 50's.. a ten degree difference!
SATURDAY-SUNDAY: Colder than normal, daytime highs in the 40's, lows near 30. While the GFS continues to scare up versions of a southern storm it is likely the most any of us will see from this is clouds and a brief spattering of wet snow. High pressure pressing in from the north looks to keep most precip south of the Baltimore area.
ST. PAT'S DAY TO THE EQUINOX: Long range indicators suggest an unstable pattern from the 16th leading up to the 21st. Will MSA's be affected by wintry weather? All I can say is that 2007 featured a snow day for central Maryland schools on 3/7, then on 3/16 many schools were either closed or had early dismissals, and Easter Saturday 4/7 featured accumulating snow across the region. You can hold fast to the belief that "it's over" but only Mother Nature's vast wisdom can make that determination!
Below: A photo gallery of the Foot girls in a week of contrasts, from cold and snowy on Monday to basking in the sunshine amidst a melting snowgirl by Friday.
The heavy snow that redeveloped across the Mid-Atlantic from mid morning to noon was due in part to the "banding" discussed earlier as the coastal low pulls away, enhanced by the passing of the closed 500 mb upper level low directly above us. This last round of snow should being tapering by 12 noon in Baltimore, but continue into the mid-afternoon across eastern PA. The enhanced fluff factor of this snow energized by the upper low may push totals to near the forecasted amounts, but some of those numbers will fall short. At least there's no bag in the forecast for me. Monitor the latest NWS snowfall reports for the metro regions of Baltimore/DC and Philadelphia (which includes northern DelMarVa).
- Peter Pan, in early 20th century works by the Scottish playwright J.M. Barrie