The Hagerstown Almanack Monthly Weather Column

                                        

  

June: Perfect for The Pool or The Ducks?

The flowers and garden sure don’t need watering here at the end of May and the warm and humid weather from earlier in the week is a figment of the imagination. You might be wondering if the occasional cooler spells will be common ground going into the first month of summer. Let’s check out the big weather players at stake and see how much/if any savings you will see on your air conditioner bill.

The two strongest patterns leading the way to shape our weather pattern in June include a transition from a negative to positive phase of the Eastern Pacific Oscillation and a reversal of the extremely negative Pacific North America Pattern to a positive phase, at least in the short-term.
 
If you are hoping to save money on watering your garden in June, you are in luck. Rainfall will likely trend near average, which is 3.87 inches for Cumberland and 4.91 inches for Oakland. We expect thefirst half of the month to deliver 75-percent of the rainfall and a drier trend for June’s second half.

The Global Relative Angular Momentum Index is the next strongest signal in our forecast. This index typically follows the El Nino (warming of the equatorial Pacific), La Nina (cooling of the equatorial Pacific waters) cycles. This past winter it coincided with El Nino and was strongly positive, with a few dips here and there. It will likely be in a negative phase for June, which makes sense since La Nina will develop during the month of June.

The Midwest, Rockies and Great Basin typically see more rainfall (thunderstorms) than average when the Global Relative Angular Momentum index is negative in June. Western Maryland and the Potomac Highlands see near average rainfall.
 
After a cool start to June, expect a big rebound in temperatures after about June 11. Father’s Day will be warmer than average with high temperatures exceeding 77 degrees in Garrett County and 83 degrees in downtown Cumberland. The region is also likely to see the cooler spells in the first half of June and hot, humid days after mid-month balance out to a hair above average for the first month of meteorological summer.
 
Reviewing the top analog years that match June 2024 very well show a strong tendency for the coldest morning with lows in the upper 40s to occur between June 6-10 and the hottest afternoon (best day for the pool) to occur between June 20-28 with highs in the mid to upper 90s. Gardens will get the biggest dose of rainfall between June 3-11. Flash flooding is possible given the likely high atmospheric moisture content available.

We mentioned last month the Main Development Region in the Atlantic, where low pressure waves develop into hurricanes, is way warmer than average. Traditionally, the first named storm in the Atlantic occurs by June 20. If we don’t see a quick spin-up off the East Coast named as a tropical depression by May 31, there is a strong likelihood for one to develop in June. However, the rainfall and wind associated with what will likely become Tropical Storm Alberto and later in the month Beryl, will stay east and/or south of our region. Historically in June, tropical systems either push up or east of Interstate 95 or make landfall along the western Gulf Coast and push into the Mississippi Valley and UpperMidwest.

Not to be outdone, the first derecho of the season already ransacked the Gulf Coast in late May. These long-lived thunderstorm wind events must produce wind gusts exceeding 57 mph along a path at least 400 miles in length and 60 miles wide. The infamous June 29, 2012 derecho slammed the Upper Midwest to the Mid-Atlantic.

Meteorologists look for the periphery of a heat ridge at 500 mb in the atmosphere to see where a potential thunderstorm cluster could grow exponentially and become a derecho. Based on available data, if one does occur in June, it would likely impact the Northern Plains to Upper Midwest.

Stay tuned for your Fourth of July fireworks forecast and a deeper dive into the second month of summer as we cruise into the final week of June. Stay safe! 





 


 

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 most recently, 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.  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.