Almanack Sees Late Winter Start
Followed by Wet Spring





(Mercersburg, PA. February 10, 2020) – The Hagerstown Town and Country Almanack’s weather prognosticator Chad Merrill issued an update to the late winter outlook that also includes more detail on the spring outlook for April and May.

The warm weather and lack of wintry precipitation this winter is due to a strong polar vortex that is keeping the cold air bottled up in the Arctic. Another contributing factor is a very strong phase of the Indian Dipole, which contributed to the Australian wildfires and has increased the number of Pacific storms this winter. After hitting the West Coast, the U.S. storm track has favored these systems pushing either through the Great Lakes or Ohio Valley.

The Mid-Atlantic has remained on the warmer side of the systems with rain instead of snow. Besides bringing an increased threat for rain, the storm track has allowed the outbreak of severe weather, such as the tornadoes that occurred in the Washington, D.C., suburbs on February 7. Six confirmed tornadoes hit the Mid-Atlantic, including five in the Washington, D.C., suburbs. This is the largest winter outbreak of tornadoes on record for the Washington area.

Going forward through the remainder of February, we don’t see the pattern shift we thought in our previous update would occur either late in February or early in March. The storm track will remain active, with above average precipitation for the Mid-Atlantic but that will mostly come from rain. The only hope for snow accumulation in February will be around the 20 with a storm that will likely produce wet snow west of the Blue Ridge that will transition to rain. The remainder of the Mid-Atlantic will see rain.

February temperatures will trend well-above average, with the coldest days occurring late this week and then again towards the end of the month. The good travel days will be February 14-18 and 28-29. We also see gusty winds, with the best chance for peak gusts this month sometime between February 20-23.

March will be mild but stormy. The only weather systems that will produce snow and ice (and it will only occur west of the Blue Ridge) will occur between March 2 and 9. Even so, snowfall accumulation will trend below average for the month. Severe thunderstorms will likely occur in the Southeast with one of the early March storms and the northern fringe of the severe weather could plague the southern Mid-Atlantic. A sizable storm at the end of March will produce all rain from the mountains to the coast, with potential for severe thunderstorms. Even if severe thunderstorms don’t materialize, we expect strong pressure gradients in these March storm systems to produce widespread very windy conditions that will contribute to power outages and tree damage.

There is small potential for wet snow in the highest elevations of the Alleghenies prior to April 5, otherwise, snow will be finished for the season between the Alleghenies and Blue Ridge after the March 9 storm system.

Snowfall amounts we expect for the remainder of the season include 6-10 inches in the Alleghenies,1-3 inches in Hagerstown, 2-5 inches in Harrisburg, Pa., 4-6 inches in Pittsburgh, less than one inch in Philadelphia and no additional snow in Washington, D.C., and Richmond, Va. Washington and Philadelphia will end up with their second least snowiest winter on record while Harrisburg, Pa., Hagerstown, Md., and Richmond, Va., end up in the top 10 for least snowiest winters. Pittsburgh’s seasonal snow will rank in the top 20 for least amount of snow in a season.

Occasional showers and thunderstorms are expected in early April with a cold blast expected about one week into the month that will bring a brief period of Canadian air. A stormy pattern will evolve with occasional showers and thunderstorms expected to resume around Easter Weekend. A dry trend will take shape later in April. This could lead to elevated fire risk but only on windy days due to vegetation in its infant stages of development for the season, a higher sun angle and lower relative humidity. However, total rainfall in April will be above average, which means more than 3.50 inches will accumulate in Philadelphia, with rainfall exceeding 3.11 inches in Pittsburgh, 3.34 inches along I-81, 3.06 inches in Washington, D.C., and likely close to 4 inches for the Mid-Atlantic coast.

We expect a few record warm days followed by brief cold blasts through mid-April, so temperatures will experience large fluctuations at times. The final hard freeze of the season will occur around April 3 along and east of I-95, April 9 along I-81 and along and west of the Allegheny Plateau between April 13-18.

May will begin dry and mild but the pattern will quickly turn stormy with occasional showers and thunderstorms that will contribute to more rainfall than average. Strong winds, perhaps severe thunderstorms, are likely with early month weather systems. A few dry days are expected between storm systems but the overall soggy pattern will continue through most of Memorial Day weekend. We do expect dry weather at the tail end of the holiday weekend. Historically, May is one of the wettest months of the year and we expect with a weak El Nino or Neutral ENSO pattern that will contribute to above average rainfall.

Chad Merrill, Prognosticator
Gruber Almanack, LLC