Limited on time for today, so I'll have to be rather succinct.
First, the rain will encompass most of Southern New England by evening, but is painstakingly slow to move north. This is a northward deviation from thinking yesterday, when I'd thought perhaps just the South Coast would get into the mix. Still looks like mostly Southern half of CT, most of RI, but almost all of SE MA, and for a few hours around 8-10 PM EDT, probably Boston and immediate North Shore with light rain or sprinkles. Bubble of high pressure analyzed as 1002 mb and weakening SE of Cape Cod has left a wake of dry air, which inhibits northward progression of the rainfall, but moist advection in the mid-levels is overcoming the shallow dry dome. Quick moving surface low will mean rainfall stays progressive, as well, pushing east by midnight. Some fog possible in areas that receive rain, but with low Tds in most areas, fog will be patchy.
Wednesday and Thursday forecast remain unchanged as upper level lows (two of them) that have been dumbbelling in Eastern Canada in a Fujiwara interaction get their acts figured out, with the easternmost vortex weakening and partially absorbed into the newly dominant western vortex that settles south over New England for both Wed and Thu, and its associated cold pool aloft means scattered convection both days. Showers and thunder likely to organize into a gusty line (dare I say squall line...surface based instability is a bit lacking, but some gusty convection looks likely) over NY State later Wednesday ahead of a sfc cold front that will be pushing east thru New England Wednesday night, but plenty of scattered convection ahead of it Wed afternoon with diurnal heating. Low enough convective temperatures to get cumulus popping by late morning and yielding precip not long after. Some thunder may produce hail in the higher terrain of Northern New England, tho for most areas the boundary layer and lowest several thousand feet of atmosphere will be too warm to support much of it, except in the heartier cells. Better chance on Thursday with colder air in place thru a deeper chunk of atmosphere.
I felt obligated to put a scattered light shower in for Friday even though, as described yesterday, I really have doubts. Nonetheless, what we also examined here together yesterday is that there is a vort max with warm advection in the mid-levels, and that's a favorable scenario for clouds and perhaps some precip, so given the guidance's persistence on this, broke down and put a drop in the forecast! :)
Love the look of the weekend. As mentioned here yesterday, gradually building temps and dry air, but that will make for high fire danger on a weekend lots of fires normally would be going.
Matt
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