7:32AM
DAYS 1-5 (MAY 14-18)
And just like that, the outlook is not quite the same. It almost caught me, and somewhat did, but there were suspicions yesterday, and as they day went on and today arrived they became larger, and the classic “spring thing” will be taking place. How big of an impact it has here is still somewhat unknown. What is the “classic spring thing”? If you ask most meteorologists who have more than 1 seasons of forecasting experience in spring in New England, they will think of either the ocean’s influence on temperature (locally), or the atmosphere’s tendency to do things that are not quite west-to-east (regionally). Both will be the case before the end of this 5 day period, and we’ll continue the story in the 6-10 day period below. But before we get there, let’s rewind to today, a nice day overall, definitely less windy and much milder than the last 2 days have been, but you’ll start to see an increase in high and mid level cloudiness as the day goes on, and this is the atmosphere’s response to increasing warmth and humidity aloft. That is a warm front approaching, and the front will get into the area, but may not completely get through it. I’m still concerned that the front may never fully make it beyond northeastern MA and southeastern NH Friday, while a good portion of the region gets into the warm sector between that warm front and an approaching cold front. So that sets up a tricky forecast for Friday, yup, the day-2 forecast, for both temperature and weather, when areas to the northeast, say Hampton Beach NH for example, could be stuck in the 50s while the suburbs southwest of Boston are pushing into the 70s. In addition, after we get through some warm frontal rainfall initially from tonight into the early hours of Friday, we’ll then have to watch for the development of showers and thunderstorms as the cold front approaches. Areas that get into the warm air stand the greatest chance of seeing the strongest storms, with a few possibly becoming severe. The greatest chance of this in the WHW forecast area would be northeastern CT, northwestern RI, and adjacent south central MA. Closer to the South Coast, a wind off the water would limit this chance, and the lack of deeper warm air would do the same in areas to the north and east of the higher risk area. So this will be something to watch – updated again on tomorrow morning’s blog post and of course when any new ideas can be shared in the comments section. Beyond that, it looks like before the “typical spring thing” happens, we’ll have a fairly decent weekend: fair weather Saturday, coolest on the coast, then increasing clouds Sunday ahead of the next low pressure system, but rainfall may hold off at least until Sunday evening, and possibly until Monday. What takes place on Monday is likely to be different than what I had been touting in previous blog posts. I’d been optimistic that what we would have been dealing with is one low pressure system coming along in the jet stream, giving us its wet weather late Sunday to early Monday, then moving along. But it’s not that simple. An area of showers and thunderstorms coming out of the Bahamas is going to enter an area off the US Southeast Coast that is favorable for early tropical development, not really purely tropical, but a hybrid type system, or potential subtropical storm, and just enough of a dip in the jet stream carrying our system in from the west will draw this system northward. When this happens, the upper level steering currents can see a low pressure area that becomes separated from the jet stream, so it doesn’t just move along and depart. It hangs around, maybe moving westward for a while or doing a loop. This process will be just getting underway Monday, which now looks wet, breezy, and chilly.
TODAY: Partly sunny. Highs 63-70 except 55-62 South Coast. Wind SW 5-15 MPH.
TONIGHT: Cloudy. A period of rain likely. Lows 48-55. Wind SE 5-15 MPH.
FRIDAY: Mostly cloudy to partly sunny. Showers and thunderstorms likely from mid afternoon on, some possibly strong, favoring interior southern MA, northern RI, and northeastern CT. Highs 55-62 South Coast, NH Seacoast, northeastern MA, 62-69 interior southeastern NH, Merrimack Valley, and remainder of southern NH and far eastern MA, 70-77 interior southern MA, northern RI, and northeastern CT. Wind SE 5-15 MPH coastal NH and northeastern MA, SW 10-20 MPH with higher gusts elsewhere.
FRIDAY NIGHT: Mostly cloudy evening with showers and possible thunderstorms, especially RI and southeastern MA. Gradual clearing overnight. Lows 48-55. Wind shifting to NW 10-20 MPH, diminishing overnight.
SATURDAY: Mostly sunny. Highs 56-63 coast, 64-71 interior. Wind SE 5-15 MPH
SATURDAY NIGHT: Mostly clear. Patchy valley fog. Lows 43-50. Wind S under 10 MPH.
SUNDAY: Increasing clouds. Highs 55-60 coast, 60-65 interior. Wind SE up to 10 MPH.
SUNDAY NIGHT: Cloudy. Chance of rain. Lows 45-52. Wind E 5-15 MPH, higher gusts coastal areas.
MONDAY: Overcast. Periods of rain/drizzle. Areas of fog. Temperatures steady 45-52. Wind E-NE 10-20 MPH, higher gusts coastal areas.
DAYS 6-10 (MAY 19-23)
This 5-day period’s weather largely depends on the movement and behavior of a broad area of low pressure just to the south of the region. Current idea is for cool/wet/breezy conditions to start, then lots of clouds and occasional drizzle/showers hanging on for a couple more days before low pressure is then replaced by a southerly air flow, warmer temperatures and higher humidity with additional showers as one of the remaining lows approaches as a trough from the west later in the period, with finally some clearing possible by the very end of the period. This complex evolution idea will probably change so monitor future updates.
DAYS 11-15 (MAY 24-28)
Watching for high pressure in eastern Canada which may put a boundary between cool Canadian air and much warmer air to the south nearby. Tricky forecast in here, but leaning toward more unsettled days than fair ones.