The Hagerstown Almanack Monthly Weather Column
April: Will April Brig Brush Fire Relief?
March 30, 2024 - We saw how quickly brush fires can develop and spread despite lack of drought coverage in western Maryland and the Potomac Highlands late in March. Given the dry end to the month, will Mother Nature return rain in April or will fire officials have their work cut out for them?
Rainfall was near to above average in March and all it took was one two dry days, a gusty frontal passage and very low humidity to trigger the wildfires in Hardy and Hampshire County.
The closest-matched analog month (April) is 2010, which was overall warm and dry in western Maryland and the Potomac Highlands.
The closest-matched analog month (April) is 2010, which was overall warm and dry in western Maryland and the Potomac Highlands.
El Nino is weakening but will remain a strong signal through April’s first third. Historically, El Nino produces an active storm track from the Southwest into the Mississippi and Ohio valleys and Appalachians. More support for a wet pattern includes a negative Pacific North America pattern. A conflicting signal is an expected negative North Atlantic and Arctic Oscillation through mid-April, which favor below average rainfall. A flip in the Arctic and North Atlantic Oscillation pattern supports more rain for April’s second half.
What all this boils down to is an active severe weather season in the heart of Tornado Alley across the southern Plains and Lower Mississippi Valley. Farther north in western Maryland and the Potomac Highlands, rainfall will likely trend near the historical average of 3.41 inches east of the Allegheny Plateau to 4.33 inches in Garrett County. One or two rounds of thunderstorms will likely occur in the second half of April.
Don’t plant flowers just yet.... a hard freeze is expected at least once in mid to late April in the wake of a strong cold front. This follows long-term climatology in the region. April 19 is the average final hard spring freeze for Cumberland while it’s May 5 in Garrett County. April temperatures will assume a sinusoidal pattern with moderate dips followed by big rises. The warmth will be more sustainable than the cold dips in the wake of fronts.
The strongest gusts occur on a west to northwest wind in western Maryland and the Potomac Highlands. The transition from a negative Arctic and North Atlantic Oscillation to a positive phase of both patterns in mid-April brings the best chance for a strong front to trigger gusty winds. Brush fires will be most likely in the first two weeks before the green-up period gets off to the races. There is a strong likelihood for a handful of brush fires to break out across the region given the antecedent conditions (dry soil).
The million-dollar question many folks want to know is the cloud cover forecast for the April 8 total solar eclipse. Even though we won’t be under totality, the sun will “dim” during the mid-afternoon. Historically, the best probability for sunny skies between Noon and 4 p.m. on April 8 occurs when the temperature is 3 to 5 degrees above the average high of 63 degrees.
The first three days of April will be chilly across the region as an Eastern trough exits. A large western trough will then setup shop in early April and produce a downstream Eastern ridge that will yield warmer than average temperatures in western Maryland and the Potomac Highlands. A cold front draped across the Heartland will likely trigger rain and thunder in the totality path across the Mississippi Valley with bubbling cumulus cloud cover in the Ohio Valley.
East of the front, high, thin clouds could filter the sun in the Appalachians, but not completely block it. The best spot along the totality path to see the moon block the sun without any cloud interference will be New England during the mid to late afternoon on April 8th.
Other national highlights will include drought improvement in the mid-Mississippi Valley, occasional flooding in the Southeast, an extension of winter snowfall for the West and the onset of sea breeze thunderstorm season in Florida.
Stay tuned at the end of April to see if western Maryland and the Potomac Highlands will dash into the last month of spring with a surplus of rain, whiplash to winter or quick transition to summer warmth and humidity.
Chad Merrill is a Cumberland native and meteorologist who not only serves as the Hagerstown Town and Country Almanack weather prognosticator but is also senior meteorologist at Earth Networks in Germantown. Merrill has previously been meteorologist with WDVM (formerly known as NBC25) in Hagerstown and at WJAC-TV in Johnstown, Pennsylvania. Most recently, Merrill was named chief meteorologist at WOAY-TV in Oak Hill, West Virginia. 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 Seal of Approval. Feel free to contact him at cmweather24@gmail.com or 240-285-8476.
