The Heavy Rain Train Returns To Town
The drought is dead, but just to make sure, nature isn't easing up on us. Can never be too careful I suppose.
After one of the wettest months in years, we've got another soaker scheduled to end this week. May picking up where April left off. Speaking of, how wet was April? In Boston it was the wettest month since December of 2014, and the 5th wettest over the past five years. Most of our area has seen 6-12" of rain since mid-March. Plenty to green up the landscape and fill some ponds.
There are, thankfully, a couple of days to dry out before the next round. A jump into the 70s will be welcome Tuesday afternoon and seasonable 60s will be here on Wednesday and Thursday. An opportunity to mow the grass or lay down some fertilizer. Then we'll watch the storm approach on Friday. Heavy rain moves in during the day and it looks like a windswept one as southeasterly winds ramp up as the day wears on. A particularly juicy atmosphere will be overhead with a plume of moisture being drawn up along the eastern seaboard, and the result should be a widespread 1-2" of rain with some locally higher amounts not out of the question.
At this time, it doesn't look like that would be enough rain to cause significant flooding issues. Our big rain events have been spaced out enough to keep things from getting too dicey, plus there have been some very warm days between rain events to help dry out. Current flash flood guidance says we'd need at least 2.5"+ of rain within a 6 hour window to cause problems. It appears we'll stay shy of that mark, but still something to monitor. At the very least it should be rough traveling around the region, especially during the second half of Friday into the overnight.
6-hour flash flood guidance from the NRFC
The steadiest rain should be winding down by Saturday morning, but the storm system itself is not going anywhere fast. This one is going to go the good old fashioned 'cutoff' route that we see in spring. Very strong high-latitude blocking is setting up over Greenland, which is fantastic if you're a snow lover in winter but not so much if you like sunny warm springs. It basically plugs up the works and stops everything in its tracks. The end result is a swirling upper-level low that should keep scattered clouds, showers, and cool air around the Northeast for several days (possibly well into next week).
Intense blocking over Greenland early next week could lead to some very interesting outcomes here in the Northeast. Source: Weatherbell
When it comes to the air associated with this one, it looks like there should be enough cold to bring snow into the Northeast. At the very least, I could see it happening across Upstate New York and the peaks of New England. Depending on wobbles in track and how long it lingers, perhaps we could even see some flakes in southern New England. I don't think we're looking at a May 1977 redux (more here) but crazy things can happen when you have a potent upper low in springtime. Will be interesting to see how it plays out. The main takeaway is that big warmth will likely stay west of us for at least the first 10 days of May. Best not to plant any warm weather crops like tomatoes, cucumbers, and peppers in the garden just yet.
