A frost advisory is in effect across much of Central New York and parts of the Finger Lakes tonight as temperatures tumble into the low-to-mid 30s, creating the potential for widespread frost formation before a cooler, rain-soaked Memorial Day weekend settles into the region.
The National Weather Service says sensitive outdoor plants and early-season gardens could be damaged or killed if left uncovered overnight. Advisories stretch across a large portion of upstate New York, including Tompkins, Schuyler, Chemung, Steuben, Cortland, Chenango, Madison, Delaware, Oneida, Onondaga, Oswego, Jefferson, Lewis, Allegany, and several eastern counties.
Forecasters say clear skies, light winds, and dry air will allow temperatures to drop quickly after sunset, especially in colder valley locations where frost development is expected to be most widespread between 11 p.m. Thursday and 8 a.m. Friday.
Frost threat arrives after unusually cool stretch
The chilly overnight setup follows several days of below-normal temperatures across the region. Highs Thursday struggled to climb beyond the upper 50s and low 60s in many areas as clouds streamed across New York behind a stalled frontal boundary.
The coldest overnight readings are expected across rural inland valleys and higher elevations, where some spots could briefly dip near freezing. Even areas not officially included in frost advisories could still see patchy frost in low-lying locations.
The National Weather Service is urging residents to protect tender plants, flowers, and vegetable gardens by covering them or bringing potted plants indoors overnight.
Friday will offer a brief rebound before the holiday weekend turns unsettled. High pressure building into the Northeast is expected to bring mostly sunny skies and milder temperatures, with highs returning to the mid 60s and low 70s for many communities.
Soaking rain expected Saturday
The quieter weather will not last long.
Forecasters say a slow-moving storm system tracking into the Ohio Valley will spread widespread rain into western and central New York beginning Friday night and continuing through much of Saturday.
Rainfall totals between three-quarters of an inch and 1.5 inches are possible across parts of western New York, with lighter but still meaningful rainfall expected farther east across the Finger Lakes and Central New York.
Saturday is shaping up to be the wettest and coolest day of the holiday weekend. Areas south and east of the Finger Lakes — including the Twin Tiers and portions of Central New York — may struggle to get out of the upper 40s and low 50s as steady rain and easterly winds lock cooler air into place.
Farther north, temperatures may briefly reach the low 60s before rain intensifies later in the day.
Forecasters also say localized ponding on roads and minor flooding in poor drainage areas will be possible if heavier rainfall bands develop, though widespread river flooding is not expected at this time.
A few embedded thunderstorms cannot be ruled out Saturday, particularly across western New York, but forecasters say instability appears limited.
Sunday improves slowly, but clouds linger
The storm system is expected to gradually pull east Sunday morning, though lingering showers and extensive cloud cover are likely to persist through at least part of the day.
Conditions should slowly improve during the afternoon, especially west of Interstate 81, where some breaks of dry weather are expected. Temperatures will remain cool for late May, generally topping out in the upper 50s to upper 60s depending on location.
While Sunday may not be a complete washout, it will likely feel damp and cooler than normal for late-May outdoor plans.
Memorial Day forecast remains uncertain
Forecasters say Memorial Day itself still carries some uncertainty, with computer models disagreeing on the timing of lingering weather disturbances.
At this point, the forecast calls for mostly cloudy skies with at least a chance for scattered showers during the day, though conditions are expected to trend warmer. High temperatures Monday are projected to reach the low to mid 70s.
The better news arrives next week.
Forecast guidance increasingly shows a stronger warming trend taking shape Tuesday and Wednesday as upper-level high pressure builds into the Northeast. Sunshine is expected to return with temperatures climbing back into the mid 70s and even low 80s in some locations by the middle of next week.
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