Welcome to the weather blog - a regular Monday through Friday discussion of the weather! While the discussions usually will only come on days I'm working, I'll issue special updates when the weather warrants. I will always post to let you know when no discussion is expected if I'm away on vacation, etc. - if no update is here and no info is available, that likely means the server has temporarily gone on the fritz and I will update as soon as technically possible. You'll find a quick weather synopsis linked to the daily forecast at the top of the page, a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow by mid-afternoon. My email is contact@mattnoyes.net. This blog is for you, so I hope you enjoy it! -Matt Noyes
General Weather Summary:
Another earthquake has rocked the Bar Harbor, Maine, area, epicentered just four miles south-southeast of the town at 8:07 PM Monday night. This quake is still being evaluated by the United States Geological Survey, but as of this writing is pegged at a 3.9 magnitude quake. Damage reported from Acadia National Park included a closed road due to fallen rocks, and burst water pipes. You can access more information on this quake from the USGS by clicking here. Certainly, three earthquakes in three weeks all centered near one town makes for interesting conversation and is thought-provoking, and while not common, this can and does happen as fault lines experience varying degrees of activity.
Weatherwise, Tuesday morning sunshine will continue to dim behind increasing clouds from northwest to southeast through the day as moisture increases in advance of a quick-moving disturbance at the jet stream level. This disturbance produced heavy thunderstorms from Chicago through the Eastern Great Lakes Monday and Monday night, and will continue to carry at least scattered showers with embedded thunder into New England by Tuesday afternoon. Ahead of the storm, its counter-clockwise circulation of air has aided in transporting warmth into New England. This warmth was responsible for sending high temperatures soaring into the 80s and 90s through the nation's midsection the last couple of days and while our warmth won't rival those numbers, high temperatures will land some 6-8 degrees above normal in New England Tuesday afternoon. Though showers will extend in scattered form across Northern New England from west to east Tuesday, as the incoming disturbance moves east it will encounter increasingly dry air, and this will allow many of the showers and embedded downpours to weaken, though certainly late afternoon and early evening may bring a shower to even eastern parts of Southern New England. These showers will dry up quickly Tuesday night with the passage of the jet stream disturbance aloft, though pockets of fog are likely to develop, especially in valleys.
The trend of fast-paced disturbances will continue into mid-week, as warmth rebounds on Wednesday ahead of an approaching strong Canadian disturbance. An increase in southwest winds will boost temperatures much above normal Wednesday afternoon - especially in Southern New England - though the surface cold front associated with the incoming disturbance will help to generate widespread showers and thunder later Wednesday from northwest to southeast, taking most of the night to press through Southern New England but finally clearing out Thursday and leaving fall air in its wake. Any storms that develop Wednesday afternoon and evening will pack the potential to deliver locally damaging winds to some communities, as winds just a few thousand feet off of the ground will be whipping out of the southwest at over 60 mph. Winds that will change direction near the surface - along a weak warm front serving as the leading edge to the deeper warmth over Southern New England - will enhance the potential for damaging thunderstorms in Central New England. As the band of rain and thunder transitions to a band of rain and embedded downpours while slowly shifting south Wednesday night, it will usher in a shot of cool and dry fall air for the end of the week. At this point, it appears as though this dry air will remain locked in place into the weekend, holding a developing storm to our south along the Mid-Atlantic coastline, keeping us dry. Admittedly, it will be a bit of a close call for Southern New England, but so far the weekend looks quite promising.
Have a great Tuesday!
Technical Discussion: Lots going on behind the scenes today...will update again tomorrow.
Matt
Matt's Technical Meteorological Discussion: Updated Monday, October 2 at 1:55 PM
Clouds waited for diurnal effects to fill in but the process has begun as of this writing and will continue to rapidly fill the sky as convective temp has been reached in most spots thanks to cool air aloft and abundant low level moisture available for convective growth. Brightest locales will be far Srn/SW NewEng. Have included gusts to 20 mph given mixing to 925 mb and winds to 25 kts progged at that level.
Cu should diminish after sunset and winds slacken which will allow cooling, tempered by moderate warm advection in the mid and lower levels. This warm advection comes in advance of an approaching shortwave currently moving across the Midwestern US that will move steadily E in the westerlies. Decent agreement on a morning passage of assoc midlevel moisture in Nrn NewEng, and afternoon passage in Srn NewEng. Shouldn't disregard the amount of moist advection occurring in advance of the shortwave, either, which brings 850 mb Tds of +11 C on Tue and is sufficient to boost SBCAPE to over 1000 J/kg. Initial concern for me was that the NMM in particular may be exercising its occasional bias of bringing llvl moisture in too quickly, but analysis of llvl theta-e progs from current data show this is a rather impressive moist tongue to be reckoned with, so felt comfortable in adding chance thunder to my shower chance for Tue.
The trick heading into Wed is how the atmosphere behaves behind Tue shortwave. That is, at first it seems self-evident that warmth returns until late Wed shortwave comes swinging thru, and my morning fcst reflected the return of this warmth. I fear, however, that I failed to give proper respect to the density of a fall airmass, as the rules are changing now that we've transitioned from summer. In summer, an airmass rebound of warmth like this would be easy to believe, but this time of the year, even a slight southward tug of cool fall air behind the lead shortwave means we have more work to erode the cool surface dome. I don't think this is going to have major implications on my forecast for NewEng from this AM, but I do think there are some important subtle details that can be garnered from properly understanding this interaction, namely that there should be at least a band of BKN midlevel clouds - probably altocumulus - that will start over Srn NewEng Wed AM then shift across the north and thicken with the approach of the next shortwave. It certainly appears as though this warm front will be able to surge north thru most of Srn/Central NewEng, but Nrn NewEng is likely to find the thickening clouds leading directly into showers assoc with approaching wave. Farther south, where warm air does rebuild well, instability rises again to over 1000 J/kg, and with better dynamic forcing I would expect more widespread rain and thunder certainly than what I'm expecting on Tue. With 850 mb llvl jet cranking from the SW to 60 kts across Central/Nrn NewEng by later Wed, severe weather is a decent potential. Let's be sure not to grow lax to this potential for thunderstorm damage and remember that this time of the year is often a potent severe weather producer given the combination of baroclinicity and dynamics. This was evidenced in Friday's tornado in Berwick, ME, and given backing flow along and ahead of warm front pushing into Ern NH/Wrn ME on Wed afternoon/evening, the atmosphere will be primed to pull a similar stunt.
The forecast becomes more straight-forward thereafter as longwave trof migrates E thru NewEng with SE US ridging extending N this weekend and anomalous cold the end of this week transitioning to anomalous warmth later in the weekend - and likely strongly anomalous given the combination of a high pressure cell shifting S of NewEng, the heat building in the nation's Southern, Central and Northern Plains, where sfc max temps were near 100, in the 90s, and 80s respectively, combined with a downsloping flow Sun.
That's all for today.
Matt