The Hagerstown Almanack Monthly Weather Column
March and April: Volatile Weather Months in the Making!
Cumberland, MD. March 1, 2025 - While we have seen a few breaks in the cold pattern at the end of February, many of you might be ready for a sustainable warm pattern, the emergence of spring and smell of flowers by now.
This winter is the perfect match-maker to a positive Tropical Northern Hemisphere pattern where the sensible weather we experienced was largely driven by patterns in the troposphere. The layer above it, the stratosphere, operated on its own and did not impact our temperature, rainfall and snowfall patterns.
On the flip side of the coin, Garrett County has seen its 22nd wettest winter (melted down snow, plus rain). There is less of a risk for brush fire development there in April given the snowpack that has been able to melt into the soil and overall winter precipitation.
This winter, we have seen a big disconnection between the stratospheric polar vortex and what is happening down on our level where weather occurs. The stratospheric polar vortex has been quite strong, with a few occurrences this month where it weakened to normal and split (leading to cold outbreaks).
This winter is the perfect match-maker to a positive Tropical Northern Hemisphere pattern where the sensible weather we experienced was largely driven by patterns in the troposphere. The layer above it, the stratosphere, operated on its own and did not impact our temperature, rainfall and snowfall patterns.
As we move through early March, we have to bite the bullet with a colder pattern. This is largely due to the Alaska Ridge returning and pouring the cold air from the far northern latitudes into our region.
We will quickly flip back in the opposite direction for mid-March with a much warmer spell of
temperatures. Then, another Pacific pattern change will bring more cold weather at the end of March to early April.
The good news is the overall monthly temperature will be above the 30-year average of 42.1 degrees. The coldest morning temperature will occur between March 7 and 11. Rainfall will trend above the average of 3.40 inches, but snowfall will fall short of the 6.8 inches that typically falls in March.
Southern California into the Southwest, southern Plains and Lower Mississippi Valley will trend drier than average in March. The Pacific Northwest, northern Rockies, Great Lakes, Midwest, Ohio Valley, our region and the Northeast will have more precipitation than average in March.
So, when will it be safe to plant flowers? Definitely not in March, but what about April? We think the growing season will get off to a start between April 22 and April 28 in our region. This means after that time period, while a light frost or two is likely (temperature drops to 32 to 35 degrees), a hard frost with temperatures at or colder than 28 degrees for 4 or more hours is not expected. A hard frost destroys most gardens and crops that have started to sprout for the season. A light frost can damage potted flowers or plants (those with a shallow root system).
A likely negative phase of the North Atlantic Oscillation in late March to early April, perhaps spurred by a final breakdown of the stratospheric polar vortex, will bring a cold shot as mentioned before.
Research by Daniel B. Thompson and Paul E. Roundy, published in June 2013 in the Monthly Weather Review suggests about 15 days following the demise of the negative North Atlantic Oscillation comes a strong signal for East Coast warmth and very cold temperatures in the West.
This relationship also suggests an active storm track over the Mississippi Valley develops between Tax Day in April and early May. This would lead to multiple high-end severe weather threat days and, of course, rainfall. This storm track would also favor at least near average rainfall in our region in April. April 11 and 26 stand out as dates for possible severe weather (thunderstorms) in our region. Rainfall will not be distributed evenly in April. Most of the rain will fall within 3 to 5 days between April 18 and 27.
April will likely end up warmer than average, but with crazy temperature swings. In two of our three best-matched April’s for Cumberland, the highest temperature of 86 to 87 degrees occurred two to three days following the coldest morning temperature of 18 to 30 degrees. This violent temperature swing occurred between April 11 and 18 in two of the best-matched years (Aprils).
Folks must be vigilant for high fire danger days; that is warm, windy afternoons in April that have a high risk for the development and spread of brush fires. Believe it or not, this past winter ranked as the 14th driest in Cumberland and 17th driest in Frostburg (at least since 1972 to 1974) with only 5.69 to 7.38 inches (as of February 22). The persistent dry signal since last summer means our region is prime for brush fires in the spring despite more rain than average in March and April. Remember, downpours this time of the year runoff readily into creeks and streams more so than being absorbed into the soil.
On the flip side of the coin, Garrett County has seen its 22nd wettest winter (melted down snow, plus rain). There is less of a risk for brush fire development there in April given the snowpack that has been able to melt into the soil and overall winter precipitation.
The Hagerstown Town and Country Almanack’s 2025 edition is still on-sale if you are interested in purchasing one. Just email our sales manager, Jerry Spessard, at jerry.spessard@comcast.net uor call him at 301-491-4002.
Chad Merrill is a Cumberland native and meteorologist who not only serves as the Hagerstown Town and Country Almanack weather prognosticator but has previously been meteorologist with WDVM (formerly known as NBC25) in Hagerstown and at WJAC-TV in Johnstown, Pennsylvania, and was chief meteorologist at WOAY-TV in Oak Hill, West Virginia. Merrill and since has accepted the position of Senior Meteorologist with AccuWeather in State College, Pennsylvania beginning in 2025. After a rigourous evaluation, Merrill was awarded the National Weather Association (NWA) Seal of Approval. According to the association, only 1,045 meteorologists currently hold the NWA Weather Broadcaster Seal of Approval. In April, 2023, Merrill, was inducted into the prestigious Marquis Who's Who Biographical Registry! Feel free to contact him at cmweather24@gmail.com or 240-285-8476.
