12:15 PM | *A double whammy on tender and newly planted vegetation in the Mid-Atlantic/NE US…potential frost/freeze late tonight and an excessively dry air mass...some tips on protection*
Paul Dorian
An unusually chilly air mass for this time of year in the Mid-Atlantic/NE US can result in frost/freeze in many spots late tonight/early tomorrow bringing stressful conditions to tender and newly planted vegetation. Map courtesy NOAA, tropicaltidbits.com
Overview
The next couple of days will be quite stressful for tender and newly planted vegetation in the Mid-Atlantic/Northeast US given the double whammy of possible frost/freeze conditions and the influx of an excessively dry air mass. This is quite late in the season for a possible frost/freeze; especially, in the Mid-Atlantic region, but indeed that is on the table for late tonight/early tomorrow across interior sections of the northeastern states. This unusually chilly air mass for this time of year is also one that is very dry and dew points will drop into the 20’s over the next few hours.
Not only is the air mass quite chilly across the Mid-Atlantic/NE US for this time of year, it is very dry as well. Dew points which are a measure of overall humidity levels will drop into the 20’s later tonight. Maps courtesy NOAA, tropicaltidbits.com
Details
A cold frontal system pushed through the northeastern states earlier today and its passage has ushered in increasingly windy conditions and a noticeably cooler air mass compared to yesterday with temperatures already dropping into the 50’s across some of the suburbs of Philly and New York at mid-day. Temperatures will drop into the 30’s later tonight across much of the Mid-Atlantic/Northeast US and - as high pressure moves overhead and winds lighten - conditions will become favorable for frost to form in many outlying areas. In fact, a freeze is possible across upstate PA, upstate NY and interior New England with late night temperatures likely to drop to freezing or slightly below in many locations. This may be the latest in the spring season for a freeze across some sections of upstate PA and NY in many decades.
High pressure will push overhead late tonight and winds will lighten up under clear skies…quite favorable weather conditions for a late night frost or freeze. Map courtesy NOAA, tropicaltidbits.com
In addition to the drop in temperatures, dew points have dropped sharply during the past couple of hours indicative of the dryness of this new air mass and skies will become a noticeable deep blue this afternoon given the dry air in the upper atmosphere. The dew points will likely end up in the 20’s later tonight throughout the Mid-Atlantic region and Northeast US.
This is quite late in the season for a potential frost/freeze; especially, in the Mid-Atlantic region south and east of the Appalachians where the second half of April is the typical time for this. Map courtesy mygardenlife.com
The combination of a potential late night frost/freeze and excessively dry conditions can be very stressful to tender and newly planted vegetation in the Mid-Atlantic/Northeast US. Some tips on protecting tender and newly planted vegetation are as follows:
1) If you have the opportunity, water vulnerable vegetation this afternoon or early this evening when temperatures are still relatively warm. Keeping soil moist can actually help protect plants from the cold as moist soil has an insulating effect which radiates heat upward come nightfall.
2) Add mulch to protect the plants’ root systems
3) Cover vulnerable vegetation if possible with light blankets, bed sheets, towels, burlap or drop cloths (using plastic is somewhat risky)…remove any covering early the next morning after the frost/freeze threat has passed.
4) Move potted plants indoors and move hanging baskets to porches or decks close to the house where its heat can be somewhat protective.
The National Weather Service has issued many frost and freeze advisories for the Mid-Atlantic region and Northeast US (upper, right). map courtesy NOAA/WPC
Meteorologist Paul Dorian
Arcfield
arcfieldweather.com
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