A brief visit from summer

Synopsis:

Summer will finally make a presence in New England as the ocean storms loses strength and moves out. Cold front will swing through with thunderstorms on Friday. East coast trough remains in command next week, with a continuation of clouds and below normal temperatures.

Discussion:

Temperatures started in the 60's across most of New England this morning. The lower levels remain very moist, with dew point depressions of 1 to 3C in the first 3 kilometers of the atmosphere. As a result, low clouds and fog are hanging on especially over eastern New England. The pesky ocean storm that has kept clouds, drizzle, and rain over the region for the last few days is weakening and lifting north finally, with high pressure building in from the southwest. This will promote clearing skies later today with notably warmer temperatures. Highs today should make it up into the low 80's.

A short wave will be swinging through the Great Lakes and Ontario this afternoon. The associated cold front will be the focus for thunderstorm activity across the Great Lakes with some severe weather possible as well. A prefrontal trough will approach New England tonight. With increasing instability (CAPE around 1500J/kg), an isolated thunderstorm cannot be ruled out later this afternoon and evening.

On Friday, the cold front will move in from the west with low pressure in southern Quebec. The prefrontal trough will swing through in the morning, with clouds and a chance of a shower or thunderstorm. We should see some clearing in the late morning and afternoon, and this will allow for moderate instability (CAPE 1500 to 2000J/kg) to develop ahead of the cold front. Winds will be fairly unidirectional, but there will be decent speed shear present with a 60kt 250mb jet overhead. With this in mind, some thunderstorms may be severe, with the main threat being damaging winds. High temperatures should get up into the low 80's once again, although with a early peak. Skies will partially clear in the evening, with dry conditions overnight.

The short wave will slow and deepen over the region on Saturday, keeping clouds and cooler temperature locked in place. The next piece of energy will drop into the Great Lakes region on Sunday, forcing the first short wave to rotate north. There will be a grace period on Monday in between troughs when temperatures may rebound a bit, however scattered showers will still scour the region with the development of any diurnal instability. The new wave will cutoff over the region by Tuesday, sitting in place for the better part of next week. Once again, clouds, intermittent showers, and chilly temperatures will be the rule.

By Thursday, the trough will begin filling in and lifting north ... making way for the next wave moving in on Friday and Saturday.

In summary, any long duration summer weather is not likely for the next two weeks.