Not Great, But Not Terrible Either

WED 5/14: A very nice Wednesday, albeit a bit cool at times this morning, is unfolding around the Cape today. High pressure is firmly in control, wedged in nicely between an offshore storm to our east and a cold front pushing across the Great Lakes. Temperatures will top out in the low 60s around the area Wednesday afternoon but with much lighter winds than Tuesday, it will feel far nicer. The atmosphere is actually supportive of temperatures closer to 70F, but a cool north to northeast breeze will cap readings some 10 degrees lower than they might otherwise be (and will be to our west.) Either way, the average high for this date at Hyannis is about 61 or 62, so we won't be that far from "where we should be."

Taking a step back and looking at the overall weather pattern, we see it is still one that favors generally below normal temperatures and unsettled weather. On average, an upper level trough remains anchored over the eastern half of the U.S., favoring cool temperatures and keeping storm systems on the march. We saw one system move by the region this past Friday, another Monday and Tuesday and there are several more disturbances to track in the coming days.

The first feature to watch is the aforementioned cold front moving across the Ohio Valley and Great Lakes. This cold front is attached to a low pressure center moving through Canada. While this front is currently quite active, producing a large area of showers and thunderstorms, it will tend to fizzle as it moves eastward and runs into high pressure over New England tomorrow. As such, there's just a low probability of seeing a passing shower or sprinkle Thursday amidst a mix of clouds and sunshine and temperatures in the upper 50s to low 60s.

Thursday's front will tend to stall and washout south and east of New England Thursday night and Friday. As it does so, it will help to capture moisture and energy over the lower Mississippi River Valley and funnel it northeastward towards the Mid-Atlantic and New England Friday. Aiding in this transport will be a small storm center forming along the surface boundary and riding south of New England Friday night. This system will pass near Cape Cod before intensifying and heading more northward and towards Nova Scotia on Saturday. The question for us is just how close to the region this storm travels. The majority of computer guidance does carry this feature close enough to the area to give us a period of steady rain Friday afternoon and night. While widespread heavy rain doesn't appear likely, at least some wet weather will close out our work week, with perhaps as much as 1/2 inch of rain falling around the area by Saturday morning.

Friday's storm will continue to deepen and lift northward on Saturday, eventually rotating a bit westward over Canada as it becomes absorbed by (or helps to maintain) the larger upper level trough over the region. This will put us underneath a chilly, cyclonic, unsettled flow over the weekend - a pattern that won't allow for a prolonged stretch of nice, warm weather, but also doesn't mean wet weather all of the time.

With the cylconic flow firmly in place, a cold pool of air moving in aloft, along with numerous fast moving energy centers riding along in the deep trough over the Great Lakes and Northeast, we will have to be on the lookout for periods of clouds and episodes of showers antyime Saturday through perhaps Tuesday. Unfortunately, timing and intensity of these features are very much in doubt. As such, the going extended forecast showing pop-up showers and cool temperatures for the coming weekend and early next week stands - but could be a bit misleading. The likelihood of all day rains is very low, but the probability of at least a passing shower or two and below normal temperatures is relatively high. So the bottom line is, don't cancel any weekend plans, just don't prepare for beach weather either.