Welcome to the weather blog - a regular Monday through Friday discussion of the weather! You'll find a general non-technical weather summary below, and when available (most days) a detailed technical meteorological discussion will follow. If no technical discussion is available when you check in during the morning, check back later as it often comes after the Weather Summary - I try to indicate at the end of the general weather summary when/if a technical discussion is coming. My email is contact@mattnoyes.net. While the discussions usually will only come on days I'm working, I'll occasionally issue special updates when the weather warrants. This blog is for you, so I hope you enjoy it! -Matt Noyes
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Matt's Weather Summary: Drizzle and fog has been sticking around for the morning commute in some areas on this Tuesday as warmer air continues to nudge into New England. To our west, a potent storm is churning across the nation's midsection, and after bringing blizzard conditions to the Northern Plains and severe thunderstorms with tornadoes to the Mississippi River Valley on Monday, this storm will continue marching northeast into the Great Lakes and Southern Canada. The attendant cold front will be dragging south of the storm center, passing through the Ohio Valley Tuesday afternoon as an active band of showers, downpours and thunderstorms. With a strong southerly flow of wind ahead of this front, ample moisture will pour northward out of the Gulf of Mexico, and this will mean the front will move east as an efficient rain producer. Here in New England, Tuesday will be a noticeably milder day as southeast winds continue to increase (gusting to over 35 mph along coastlines and on hilltops), and while many areas begin the day with the aforementioned drizzle and fog, most of New England will stay dry for most of the day, save for a sprinkle or light shower here and there. In fact, a few breaks of sunshine are likely to be seen throughout New England, and some Southern New England communities will warm into the 60's Tuesday afternoon! By Tuesday evening, air well ahead of the approaching cold front will begin to rise quickly enough to produce a few showers across Northern and Western New England.
Breezy conditions will continue Tuesday night ahead of the slowly approaching frontal boundary, and a band of heavy showers and downpours will move into Western New England during the overnight. These showers should move quickly enough, and be narrow enough, to limit amounts to around an inch of rainfall in Western New England Tuesday night. By Wednesday morning, this band of rainfall will become better organized as it moves east across New England and a wave of low pressure rippling along the cold front coming up from the south will add more moisture to the atmosphere, and allow the front to crank out around two inches of rain for Central and Eastern New England, with higher amounts in some spots. This amount of rain will be enough...when combined with snowmelt...to cause some flooding of streams, brooks and rivers in the State of Maine late Wednesday and into Thursday, as runoff continues to work into our waterways.
Gradual clearing follows this cool front, and while there will be a well of cold air to tap behind this system, it may take an extra day for the cold to really come pouring in - allowing temperatures to rise near or even slightly above seasonal levels on Thursday. Meanwhile, to our south, a coastal storm will be taking shape later Thursday off the Mid-Atlantic coastline. With the slug of cold air slow to trudge in from our west, the frontal boundary that pushed Wednesday rain through New England may slow or even stall just off the coastline as this new storm center moves northward on Thursday. While this may keep the storm far enough east to spare most of New England from its precipitation shield, Eastern New England needs to watch this storm particularly carefully, as it may deliver a shot of showers to some locales on Thursday, and more likely will deliver accumulating snow - perhaps significant - to eastern and northern Maine Thursday night into Friday.
Regardless, all of New England will feel the effects of this storm, as it will strengthen handily while pulling into Eastern Canada on Friday and this will shift winds to the northwest in the counterclockwise flow of air around the storm center. These winds blowing from the northwest will tap into a pool of cold air in Central and Southern Canada, ushering this chill into New England for the end of the workweek and the upcoming weekend. I wouldn't be surprised to find this arctic shot of air holding temperatures in the 20's and 30's on Friday, and only in the 20's for just about everyone on Saturday! At this point, Sunday looks cold as well, and thereafter we have to watch the atmosphere very carefully. In an atmosphere with a fast flowing jet stream - like the setup we have now - strong disturbances flow through the atmosphere. These disturbances often can grow into larger storms on the back edge of arctic air, and we'll be watching this potential carefully for the start of next week.
Enjoy the mild air.
Matt
Matt's Technical Meteorological Discussion: Updated Tuesday, November 29 at 4:45 PM
Just a quick note here to update/lay out my thinking. Showers have already developed in Western NewEng - and rain will move into these areas overnight. AM commute will feature rain most of NewEng excepting Central/Eastern ME. I didn't follow the GFS QPF distribution and instead weighted the NAM a bit and followed it's precip pattern - thus bringing heaviest overall rainfall amounts to Maine. Liked the secondary and tertiary maxes of the SUNY SB MM5 in the White Mountains and in Southern NewEng, as wave of low pressure rippling north along front will bring a surge of high Theta-E air at 850 mb and precipitable water values spike as the wave approaches. Only went with .5-1" in Western NewEng. Hence, not worried about widespread flood problems in VT, only in ME where snowpack will combine with runoff to bring streams and rivers up.
Rain falls for most of the day in Eastern NewEng, and falls heavily at times with aforementioned sfc wave passage before tapering Wed eve. Next wave on the front has been of some concern given proximity to NewEng and lack of real deep cold advection to force baroclinic zone farther east. Synoptic 500 mb flow certainly looks nasty enough on Thursday into Thursday night, and I have no problem buying the accumulating snow event that appears to be in the cards for Eastern, Central and Northern Maine late Thursday into Friday. There are still questions in my mind for the rest of Eastern NewEng, though, and I've maintained a chance of rain on Thursday. The operational models have not been putting out precip, but the 500 vorticity and even 700 RH fields look ominous, and I don't trust this look. I've seen especially the NAM do this before - where the middle and upper level features look supportive of the storm and it doesn't correctly resolve the low level features until later in time, so I'm staying cautious for now.
Still expecting the cold to start pouring in on Friday and be more intense for Saturday. Still cold on Sunday as one system passing to our south will be watched, but likely passes south of us with high pressure holding on just a bit too strong. The Tuesday system is obviously being keyed in on by the operational GFS among others. Certainly this has the potential to be a large storm and a snowmaker somewhere - and if we can get enough of a break between cold Canadian highs, this will be a storm that can run the coast.
Matt
