Jun 18, 2017 8:42 PM
Severe storms expected to develop in NH Monday
A warm, humid airmass moved in over the weekend and it will remain firmly in place on Monday. A cold front approaching from the west will spark widespread downpours and thunderstorms in western and northern New England Monday. The potential exists for any of these storms to become severe in New Hampshire.
Storms may begin as early as noon in western and northern New Hampshire.
The storms will be very slow to move east, so it may take much of the day – perhaps until 6 p.m. or even later – for any storms to reach the Merrimack Valley or seacoast.
Due to the slow eastward movement, flash flooding is a primary concern, especially in western and northern New Hampshire. Storms are expected to 'train' or track over the same areas time and time again. Accordingly, a flash flood watch is in effect for western and northern parts of the state.
In addition to the heavy rain, damaging wind gusts over 60 mph are possible in the stronger storms.
The threat for a tornado in New England is low, but not zero. It is nearly impossible to say where and when a thunderstorm could produce a tornado ahead of time. However, very humid air and changes in wind direction/speed with height (known as shear) are key ingredients to making a tornado.
The Storm Prediction Center has placed much of the state in a level two out of five (known as 'slight') risk for severe weather and the southwestern part of the state in a level three out of five (known as 'enhanced') risk for severe weather. In New Hampshire, it is rare for a threat to be above three out of five.
Follow updates on NH1.com throughout the day Monday.