Hello everyone!

Today will feature mostly cloudy skies and warm temps with highs rising well into the 40’s. Any rain from our approaching system should hold off until late afternoon for southwest areas and for everyone else, any precip arrives after dark.

Tonight, rain moves in and becomes steadier and heavier as our storm begins to develop. Expect light NE winds as this storm will not be very strong nor will it be intensifying all that fast.

Tomorrow features heavy rain and breezy conditions. Expect highs in the low 40’s. Rain should become lighter as the afternoon progresses but as I will explain below, precip could hang around until midweek.

Monday through Wednesday will feature light to moderate rain/freezing rain/snow even at the coast. I expect Sunday night into Monday morning to be the worst in terms of icy conditions.

Late week we clear out and warm up into the upper 40’s under sunny skies. More rain/freezing rain/snow is possible next weekend but there are still a lot of details to be worked out.

Keep in mind, the storm could stall far enough offshore to get sunny and upper 40’s starting Monday or Tuesday. This is a very finicky pattern so keep in mind that is a possibility though don’t expect it.-

As spring arrives and warm and cold air battle it out over the US, we often get low pressure systems that are ‘cut off’ from the rest of the jet stream. They will meander around extremely slowly (anyone could out-jog them fairly easily) while bringing rainy/snowy weather to whichever area they happen to be in.

This is the kind of setup we will be stuck with over the next 5 days. The low will stall off Cape Cod and sit there with no interest in moving an inch. As a result, prolonged periods of rain and freezing rain are expected. It looks like the mountains will be too far away to get any more snow but that is also a possibility just as no precip is.

Expect QPF (Quantitative precipitation forecast which is the amount of liquid forecast to fall from the sky. Usually 1″ of QPF is 12″ of snow) amounts around an inch for the mountains and between 2 and 3 inches at the coast. This will fall starting this afternoon into tonight and last until Tuesday or Wednesday.

I think that the majority of that will fall as rain for the coast but starting Sunday evening, a flip to freezing rain is likely. I expect freezing rain amounts to be between 1/4″ and 1/3″. I will go into more detail below.

Zone 1: Heavy snow. Snowfall amounts between 12 and 18″ with 24″ amounts possible. Expect snow to start tonight and end tomorrow night. Winds out of the NE at 10-15 mph. Temps in the low 30’s.

Zone 2: Heavy snow with a little rain possible. Snowfall amounts between 6 and 12″ Expect snow to start tonight and end Monday. Winds out of the NE at 10-15 mph. Temps in the low to mid 30’s.

Zone 3: Rain/freezing rain with a little snow. Snowfall amounts between 2 and 6″. Freezing rain amounts between 1/4 and 1/3″ Expect snow to start tonight and change to snow tomorrow before turning back to snow Monday.  Precip ends Monday or Tuesday. Temps in the low to mid 30’s.

Zone 4: Rain with some freezing rain. Freezing rain amounts between 1/4 and 1/3″ Expect rain to start tonight and possibly extend through Wednesday. Rain amounts 2-3″. Temps in the 40’s tomorrow falling into the 30’s tomorrow night through Tuesday/Wednesday.

Zone 5: Rain. Rain amounts 1-3″ higher amounts in the NE sections. Along the Maine coast, freezing rain is possible Monday through Tuesday/Wednesday. Precip ends Tuesday/Wednesday.

I am concerned about flooding because there is a heck of a lot of water locked up in the snow in the foothills and mountains. In areas forecast to get 2-3″ of rain, up to 10″ is locked away in the snow. Not all 10″ will melt but there are sure to be problems with this kind of a setup.

This map shows how much water there is in the snow. Click to enlarge.

As hard as it is to believe, there are still ice jams on the rivers left over from the January thaw. When new water flow into rivers already ice-jammed, minor flooding is likely.

Most of the area is under a flood watch from the NWS with the exception of far northern areas which are under a winter storm watch.

After this storm, warm and mild conditions are locked in place as we sit under high pressure. However, all good thing must come to an end as wet weather threatens for next weekend.

-Jack