Jun 7, 2016 1:24 AM
NH1 First Alert Weather with Joe Joyce: Tracking Tuesday Thunderstorms
NH1 Chief Meteorologist
High impact weather potential for Tuesday as we will be tracking scattered strong to severe thunderstorms over the course of the day. The best chance of strong severe storms will be across southern New Hampshire and Southwestern Maine Tuesday afternoon into the early evening hours.
First things first. There will be a few passing showers early this morning tracking across New Hampshire between the hours of 6 AM-9 AM. There may be a batch of locally heavy rain accompanying these showers. Meanwhile, an upper level short wave will approach New England today. This short wave will act as a trigger for mid afternoon convection to begin to fire up.. Accompanying the short wave will come with strong winds aloft. These strong winds aloft will help to tilt storms allowing for steady rising air to help fuel updrafts...providing ample support for organized severe storms to develop. The sticking point, as is often the case, is more the available moisture and the instability.
Ahead of the wave, surface temperatures will climb to near 80 across southern portions of the forecast area. Dewpoints, which are currently in the mid 50s, will hold steady or even rise to near 60 across the south. This will be just enough to generate some afternoon storms. Several models and high resolution guidance suggest a series of severe storms moving through southern New Hampshire with the first batch arriving as early as midday-into the early afternoon Tuesday.
Early morning showers and clouds could provide a stabilizing influence to the weather. Showers will need to clear out by mid morning for enough heating to occur for storm initiation. After a few midday storms, I expect a few more breaks of sunshine during the afternoon. Here is where temps will boost to near 80, and the atmosphere should really destabilize enough to get some strong storms to pop across southern New Hampshire.
Any storms which form will be localized and come with the potential to produce small hail. Furthermore, damaging winds are also a possibility as mid level dry air may entrain into any downdrafts. Bottom line is Tuesday has the potential for a busy afternoon across southern areas. The potential for severe weather will last through about 8 PM before falling apart without the energy of the sun.
A strong short wave trough will move across northern New England on Wednesday. With cold temperatures aloft, weak instability will likely develop and aid again in the development of scattered showers and a few scattered thunderstorms. A couple of storms may produce small hail again with the cooler air aloft, and lowering freezing levels.
Fair weather follows for the middle to end of the week. Northwesterly upslope flow regions of NH and the Maine mountains will likely be on and off Wednesday night into early Friday with a few periodic showers. Dry and cool weather is expected Thursday and Friday with highs in the Lwr-mid 60's. However, then next low will begin to move our way by late Saturday. Saturday will again be the pick of the weekend with sunshine and highs in the Lwr-mid 70's. Showers will start to approach Saturday night. A stronger low may track right over us and then off the coast Sunday with a period of showers and rain which could put a damper on second half of the weekend. Cool and potentially cloudy weather lingers Sunday and Monday with upper low lingering.