Severe Storms, Air Quality Health Advisory: Hudson Valley Forecast

HUDSON VALLEY, NY — A hazardous weather outlook has been issued for Orange, Putnam, Rockland and Westchester counties, and an air quality advisory has been issued for Rockland and Westchester along with NYC.

The pollutant of concern is ground-level ozone, a major component of photochemical smog formed in summer heat. The health advisory will be in effect 11 a.m. through 11 p.m. as temperatures climb into the upper 80s.

It may be mitigated Friday afternoon by thunderstorms at the edge of an approaching cold front.

"Some of the thunderstorms can be severe, producing large hail, strong damaging wind gusts, localized flash flooding , and frequent lightning," Todd Snow of Hudson Valley Weather said on Facebook. "Charge cell phones, flashlights, etc."

The severe storms are just the first part of the National Weather Service's hazardous outlook.

That front will keep temps in the low 80s over the weekend, but then the first heat wave of the season may start on Tuesday with peak heat index values above 95 possible. Heat will likely continue into midweek.

"According to AccuWeather figures, at least 110 million people across the eastern United States will experience a heat wave next week, including areas from the Mississippi Valley to southern New England," said Brian Lada, AccuWeather meteorologist and staff writer.

DEC and DOH issue Air Quality Health Advisories when DEC meteorologists predict levels of pollution, either ozone or fine particulate matter (PM2.5), are expected to exceed an Air Quality Index (AQI) value of 100.

Automobile exhaust and out-of-state emission sources are the primary sources of ground-level ozone and the most serious air pollution problems in the northeast. This surface pollutant should not be confused with the protective layer of ozone in the upper atmosphere.

Ozone is not a direct emission, and is produced indirectly when sunlight chemically reacts with nitrogen oxides (NOx) and volatile organic compounds (VOCs) from automobile exhaust and industrial emissions. High ozone is not as visible as PM2.5 because it is a colorless gas, but will produce hazy skies and reduce visibility in high concentrations.

People, especially those with cardiovascular disease and those who have respiratory disease (such as asthma), young children, those who exercise outdoors, and those involved in vigorous outdoor work should consider limiting strenuous outdoor physical activity when ozone levels are the highest (generally afternoon to early evening). When outdoor levels of ozone are elevated, going indoors will usually reduce exposure. Individuals experiencing symptoms such as shortness of breath, chest pain, or coughing should consider consulting their personal physician.

Ozone levels generally decrease at night and can be minimized during daylight hours by curtailment of automobile travel and the use of public transportation where available.
New Yorkers also are urged to take the following energy-saving and pollution-reducing steps:

• use mass transit or carpool instead of driving, as automobile emissions account for about 60 percent of pollution in our cities;
• conserve fuel and reduce exhaust emissions by combining necessary motor vehicle trips;
• turn off all lights and electrical appliances in unoccupied areas;
• use fans to circulate air. If air conditioning is necessary, set thermostats at 78 degrees;
• close the blinds and shades to limit heat build-up and to preserve cooled air;
• limit use of household appliances. If necessary, run the appliances at off-peak (after 7 p.m.) hours. These would include dishwashers, dryers, pool pumps and water heaters;
• set refrigerators and freezers at more efficient temperatures;
• purchase and install energy efficient lighting and appliances with the Energy Star label; and
• reduce or eliminate outdoor burning and attempt to minimize indoor sources of PM 2.5 such as smoking.

The AQI was created as an easy way to correlate levels of different pollutants to one scale, with a higher AQI value indicating a greater health concern, said New York State Department of Environmental Conservation Interim Commissioner Sean Mahar and State Department of Health Commissioner Dr. James McDonald.

Here's the five-day NWS forecast based on Brewster:

Friday
A slight chance of showers and thunderstorms, then showers and possibly a thunderstorm after 2pm. High near 86. Southwest wind around 7 mph. Chance of precipitation is 80%. New rainfall amounts between a half and three quarters of an inch possible.

Tonight
Showers and possibly a thunderstorm before 11pm, then a chance of showers between 11pm and 2am. Low around 59. Northwest wind around 6 mph becoming calm in the evening. Chance of precipitation is 80%. New precipitation amounts between a half and three quarters of an inch possible.

Saturday
Sunny, with a high near 79. North wind 8 to 10 mph, with gusts as high as 21 mph.

Saturday Night
Mostly clear, with a low around 49. North wind 3 to 6 mph.

Sunday
Sunny, with a high near 79. Light and variable wind.

Sunday Night
Partly cloudy, with a low around 57.

Monday
Mostly sunny, with a high near 85.

Monday Night
Mostly clear, with a low around 64.

Tuesday
Sunny, with a high near 93.

Tuesday Night
Mostly clear, with a low around 66.