Heat, Bad Air, Thunderstorms: Hudson Valley Wednesday

HUDSON VALLEY, NY — Temperatures will reach 90 degrees in the region on Wednesday before a storm front comes through, and an air quality alert has been issued.

The National Weather Service has issued a hazardous outlook, warning of scattered strong to severe thunderstorms in the afternoon and into the evening. The storm cells are expected to track eastward at a speed of 30 to 40 mph.

Strong to damaging wind gusts will be the main threat. Hail and even an isolated tornado are also possibilities. While most of the thunderstorms aren't expected until after sunset, a few storm cells could move through earlier.

"Our primary concern for severe weather is likely with the isolated T-Storms that could develop," said Alex Marra and Bill Potter of Hudson Valley Weather.

HVW took this moment to unveil a new feature: the Stormpact Scale. It shows in graphics the potential impacts of any severe weather event, the possibility of power outages as a result, and — from folks who are cautious about their forecasts and up-front about the uncertainties — a confidence meter.

For Wednesday, the confidence meter on the Stormpact Scale is at average, "because we have high confidence the front will push into the region late Wednesday, but a low to average idea of if and where the isolated storm cells will develop ahead of the front."

The New York State Department of Environmental Conservation issued the Air Quality Health Advisories for Dutchess, Orange, Putnam, Rockland, Ulster and Westchester as well as New York, Bronx, Kings, Queens and Richmond counties.

It is in effect until 10 p.m.

When pollution levels are elevated, the New York State Department of Health recommends that people consider limiting strenuous outdoor physical activity to reduce the risk of adverse health effects. People who may be especially sensitive to the effects of elevated levels of pollutants include the very young, and those with preexisting respiratory problems such as asthma or heart disease.

Gov. Andrew M. Cuomo directed state agencies to prepare emergency response assets for the severe thunderstorm forecast. He urged New Yorkers to remain alert for potentially hazardous weather and check local forecasts continuously for changing conditions.

Here's the five-day forecast from the NWS:

• Wednesday - A chance of showers and thunderstorms, mainly after 5pm. Mostly sunny and hot, with a high near 90. Southwest wind 8 to 11 mph, with gusts as high as 21 mph. Chance of precipitation is 30%. New rainfall amounts of less than a tenth of an inch, except higher amounts possible in thunderstorms.
• Wednesday night - Showers and thunderstorms likely before 10pm, then a chance of showers between 10pm and 2am. Mostly cloudy, with a low around 63. Southwest wind 5 to 9 mph becoming calm after midnight. Chance of precipitation is 60%. New precipitation amounts between a tenth and quarter of an inch, except higher amounts possible in thunderstorms.
• Thursday - Sunny, with a high near 78. Light west wind becoming northwest 5 to 10 mph in the morning.
• Thursday Night - Partly cloudy, with a low around 48. North wind 3 to 6 mph.
• Friday - A chance of rain before 11am, then showers likely, mainly after 2pm. Mostly cloudy, with a high near 64. Northeast wind around 6 mph. Chance of precipitation is 70%. New precipitation amounts between a tenth and quarter of an inch possible.
• Friday Night - Showers likely, mainly before 2am. Mostly cloudy, with a low around 46. Chance of precipitation is 60%. New precipitation amounts between a quarter and half of an inch possible.
• Saturday - A chance of showers before 8am. Partly sunny, with a high near 64. Chance of precipitation is 30%.
• Saturday Night - Partly cloudy, with a low around 45.
• Sunday - Mostly sunny, with a high near 68.
• Sunday Night - Partly cloudy, with a low around 46.
• Memorial Day - Mostly sunny, with a high near 74.
• Monday Night - Partly cloudy, with a low around 50.