Welcome to the weather blog! While the web address has changed, the blog will still be the same Monday through Friday discussion - with some improvements! Over the course of the next few weeks and months, you'll find me experimenting and adding new features. Maps, pictures, and other multimedia are enhancements I'm hoping to be able to make as I learn more about how to maximize the new site. Format will be similar to the old version - 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. This blog is for you, so I hope you enjoy it! -Matt Noyes
For latest radar imagery, to check for watches and warnings, and for links to sites in the world of weather, feel free to click over to my website: www.mattnoyes.net
Matt's Weather Summary: Welcome back! We're starting our day with an amazing difference in temperature around New England this Wednesday morning. Pre-dawn temperatures are in the 60's from the South Shore of MA to the South Coast of CT, then all the way up the Berkshires and through Vermont. Meanwhile, the leading edge to this warmth - defined as a warm front in the world of meteorology - is nudging slowly northward through Southern New England. With the surge of increasing warmth and moisture is plenty of dense morning fog. As warm air continues to move into most of Central and Southern New England through Wednesday, we'll find temperatures climbing into the 60's, breaks of sun through the clouds in some spots during the afternoon, winds shifting to the south and southwest in the warm air and gusting to 45 mph, and the boundary of warm and cold air sliding north to the White Mountains and the Maine Coastline, where fog, clouds and drizzle will persist through most of the day. Our gusty winds come on the warm side of a strengthening counter-clockwise turning area of wind - a low-pressure center - that's cranking up through the Great Lakes and into Canada. That counter-clockwise flow of air around the storm is what's allowing winds to turn from the south across most of New England today, and the strength of the storm is what's helping to drive the winds so fast. But behind this storm, the very same counter-clockwise wind flow means a driving north and northwest wind across the Upper Midwest, and this is bringing with it a shot of very cold air from Central Canada with early morning temperatures below zero in some areas! A shot of this cold will come in modified form to New England by the end of the week.
But in the transition there will be showers, downpours and thunderstorms along the leading edge to cooler air - a cold front. This cold front has been an active severe weather producer for the past few days and is likely to produce some very strong storms Wednesday from New York State through the Mid-Atlantic. Here in New England, with winds already gusting to 45 mph it won't take much to create damaging winds within a thunderstorm, and as the cold front and line of associated storms approaches Wednesday late afternoon (western New England) and evening (eastern areas) you'll want to check my main website, www.mattnoyes.net for the latest radar imagery and to check for active watches and warnings. Regardless of wind strength in the storms, rains should be quite heavy with the passage of the front.
By Thursday morning, showers may be lingering on the Cape and Islands and in Eastern Maine around dawn, but soon after we'll find drier air moving in and this will help to bring the sunshine out. With cooler air in place, highs will only make it into the middle and upper 40's. At the jet stream level, high in the sky, a disturbance will be moving toward New England from the Great Lakes Thursday afternoon, and will be driving a wind shift from west to northwest at the surface. When this wind shift reaches the mountains of Vermont and New Hampshire late Thursday afternoon and evening, snow squalls are likely, and some of these squalls may bring a shot of briefly heavy snow.
This wind shift to the northwest will be a dry transition for the rest of New England, but the result will be the same for all of us - a direct flow of colder air from Canada! By Friday, I'm expecting dry enough air for sunshine everywhere, but temperatures will struggle to get out of the 30's, even in Southern New England! Friday night, another disturbance will move through New England at the jet stream level, and some clouds are likely with the chance of a few flurries.
The weekend features slightly warmer temperatures (back into the 40's) but the flow of disturbances at the jet stream level continues into New England. In fact, these jet stream disturbances are nothing to scoff at - there's enough energy here that if they approach at the right angle, come in a bit more intense, or merge with other energy centers, we would have a larger storm center to deal with this weekend with the threat for accumulating snow. At this point, however, it doesn't look like these disturbances give us more than flurries overnight Friday night and then again Saturday night, with lingering clouds early Saturday morning, then perhaps for a longer time Sunday morning. Check in again over the next couple of days on this, though, to make sure these subtleties still look to be on-track.
Have a wonderful Wednesday!
Technical Discussion: First part below, more to follow.
Matt
Matt's Technical Meteorological Discussion: Updated Wednesday, November 16 at 3:25 PM
**Extended discussion added below, as promised in earlier update. Delayed due to server problems. Enjoy!**
Hills will continue to be the major obstacle for warmth as it surges north and northeast into NewEng. Orography has played a large role in warm air transport - or lack thereof - thus far today, with the valleys and coastal plains exposed to the south allowing for significant warm advection while hills and areas deeper into cold surface dome are slow to shake the cold. This trend will continue today, but as the 925 mb jet increases to over 40 kts this afternoon, warmth will eventually win out all the way up to the Southern ME coastline, and likely thru the Lakes Region of NH. From the Northeast Kingdom of VT to all other areas north of where I mention, cool air stays in place. The exception is the Downeast Maine where dew points in the 50's spread in, but with water cooler, this will mean the areas of fog and low clouds persist in this area.
Active cold front continues to march eastward and carries an impressive history of severe weather production. Instability appears in pockets across NewEng today where some insolation has occurred. Plenty of moisture at all levels this afternoon as precipitable water values climb to between 1.50 and 1.75". Anomalously high precipitable water values often can lead to anomalously high rainfall amounts, though today's threat is mitigated by a steady eastward motion of the frontal boundary, and by the relatively narrow band of strong upward ascent associated with the tight baroclinic zone. Still, we should see a spectacular meteorological show for those who are attentive to detail: Falling heights and cyclonic vorticity advection will contribute to increasing ascent in the forced band ahead of the cold front, and this will tap the high precipitable water values to create torrential, blinding rains in heavier convective cells. The low level jet cranking over NewEng from the south will make it easier for stronger convective elements to bring damaging winds to the surface, even if little or no lightning is present in the cell. Greatest instability will be present east of the Hudson Valley and through Western MA and Western CT, and as convection intensifies later this afternoon and early this evening in these areas, mesolow may develop over NW CT and then ripple NE along the frontal boundary. This would enhance lift along and south of the northward migrating mesolow, as it merges with another stronger low pressure wave on the front that will be moving over Northern NewEng. The result of this interaction will be increase from south to north the greatest lift along the front as the entire line progresses eastward through Central and Eastern NewEng. Due to lack of instability farther north and east, I'm not convinced on much thunder and lightning, but I don't need to be for this front to still put on quite a show. The merger of mesolows should occur over Eastern NH or Western ME, and this will enhance the low level jet to 70 knots at 925 mb over the Gulf of Maine! Forcing should still be sufficient for low-topped convective elements to carry wind gusts of over 65 mph to the surface along the coast of Downeast Maine overnight Wednesday night. Elsewhere, perhaps one of the "surprise" features of the front (I guess I'm spoiling the surprise right now if it ends up happening) is a sudden and dramatic scouring out of the cold air across Northern NewEng immediately preceding the front, as surface pressure gradient increases ahead of these mesolows and the front just enough to rapidly transport boundary layer warmth northward.
By Thursday morning I've continued a chance of a shower on Cape Cod and in Eastern Maine for early in the day, but the air coming in behind this front is a bone-dry at 700 mb as one could get. Aloft, mean flow is not parallel to the boundary like it was last week, so I'm not as concerned about cirrus and altocirrus hanging around this time. Cold advection underway but the more significant cold hangs back, and with 850 and 925 temps falling steadily - but gradually - through the day, downsloping flow and sunshine should be able to get afternoon temps into the 40's. Winds will back in Western NewEng and especially Vermont ahead of an approaching shortwave and associated surface trough. This trough will have enough low level directional convergence...enough cold air aloft for sufficiently steep lapse rates...and enough low level CAPE by the time it passes late afternoon and evening...to generate snow showers and heavier snow squalls in a weak WINDEX event for Vermont Thursday late afternoon and evening. This should bring heavier squalls to the mountains of Vermont and Northern New Hampshire where orography will further assist in low level lift Thursday evening. If the trough arrives early enough, some areas will experience melting of the snow on pavement, and cold air will come in behind this trough so black ice is a concern for mountain roads in addition to snow cover for the harder hit areas. One could make a case for this trough to actually be considered a second cold front, and that's probably more accurate terminology given that winds veer to northwest behind it, and a true shot of Canadian cold comes pouring in. As a result, expect a cold night Thu Night, held up a bit only thanks to an active wind.
By Friday, I've held temperatures in the 30's for even downsloped Southern NewEng. 850 temps of -10 to -12 and 925 temps of -6 south and -10 north do not support temperatures above this, even with downsloping and sunshine factored in. Some of Northern NewEng will stay in the 20's.
The next shortwave will be racing eastward later Fri, and I've increased high altitude clouds late. Overnight Fri night, I'm carrying a chance of flurries with the passage of this shortwave, and once again low temps will be held up from where they could bottom out, this time thanks to clouds riding overhead with the shortwave. Saturday may start with leftover clouds, but sunshine should return and the surface ridge axis begrudgingly moves overhead and to our east, allowing some low level warm advection to move back in. Of course, this warm advection is occurring ahead of yet another shortwave - this one strong - that will be dropping across the Great Lakes and poised to move over NewEng. The models continue to insist this will not be a big deal as the shortwave comes thru, but there is a lot of energy here, and it's carrying its own mid-level moisture. For now I've included a chance of flurries Saturday night into Sunday morning should a piece of this slide through.
That brings us to the tricky and complicated situation for early next week. I mentioned above that a piece of this strong vorticity maximum may slide through Saturday night, but the bulk of it by far is forecasted to drop southward. Though the trough is positively tilted, it is quite amplified and 300 mb wind flow suggests forecasts for a large chunk of this energy to drop over the Southeastern U.S. are likely on target. Yesterday's 12Z ECMWF was far west compared to the other guidance with this energy and the resultant closed upper low that develops, but the 00Z run came farther east. The GFS takes the vort max farther east as it drops across the Southeastern US later this weekend, but allows it to go negatively tilted as it ushers a surface low up the coast. The NOGAPS is a middle of the road solution, and the Canadian is similar, though by far the most intense. Ensemble members show a significant spread both in the handling of this energy, and in the northern stream shortwave to immediately follow it. Let's begin with the former. The error in yesterday's Euro run of being too far west is likely the result of the ECMWF tendency to close systems off too quickly when the dip south. The positive tilt of the trof initially won't allow for this scenario, so I was glad to see the new run come farther east with the upper low. There is good agreement now among operational guidance to bring this energy over the SE US as a closed low, and the synoptic pattern associated with this - combined with intense baroclinicity from ocean waters still running in the mid 70's off the Carolina coastline is almost certain to generate a coastal low off the Carolinas late Sunday or early Monday. It just makes sense given low level baroclinicity, upper level cold pool with the upper low, and increasing upper level diffluence to evacuate air aloft. There will be plenty of juice for this storm to feed off of, and the questions for New England and the Mid-Atlantic will hinge upon northern stream energy (yet another vort) and how that will align the northern stream flow. A slower and more amplified shortwave will allow flow to back aloft enough to allow the coastal creature to come northward. You can make a pretty good argument for this solution to pan out: A major ridge and associated above normal height anomaly will be taking shape over the next week centered over the Western US coastline - centered over extreme SW Canada. This ridge shape and intensity is rather persistent, and given the large wavelengths that will be developing across the entire Northern Hemisphere, to carve out a large anomalously low height area somewhere near or over Pennsylvania will complete the latitudinally balanced trof-ridge-trof pattern that will be establishing from the East-Central Pacific through the Eastern US Seaboard. Also, with the high sitting over the Western US through the weekend, this will favor a rather meridional north to south flow of shortwaves almost directly from the north pole. These shortwaves, incidentally, are ejecting out of the East-Central Pacific low...riding all the way over the ridge to the pole, then dropping south around the eastern periphery of the ridge. This means two things: 1) Amplified shortwaves, and 2) cold shortwaves. So my thinking for now is that the northern stream follow-up shortwave is likely to be amplified enough to allow the coastal creature to come north. But if that is the case, precip type becomes the next concern. At this point, there is no high pressure that seems close to give us a solid shot of immovable cold. Instead, our cold air pours in only thanks to the repeated blast of shortwaves dragging it down. This usually ends up meaning the mountains and ski country can end up doing well and picking up snow provided the timing is right, while most of Southern New England and the coastal plain ends up just a touch too warm. But don't go holding me to precip types on imaginary storms that are 5 or 6 days out just yet, OK? :)
But regardless of how this particular one ends up playing, misery loves company and the trof-ridge-trof setup on this side of the hemisphere...coupled with the lack of a well defined pattern over Russia...is likely to allow for longwave retrogression on the other side of the pond. That is, the ridge in place over Western Europe should retrograde, and actually is depicted by many Ensemble members to complete the cycle, so to speak, and line up over Greenland by Thanksgiving. Trough-ridge-trough-ridge. Gorgeous. What this means we all know - negative NAO pattern takes hold, and Greenland block actually may bridge the north pole to Siberia by Turkey Day weekend. The result of this is a lingering closed low over the Eastern US, and that means cold weather for an extended period. The biggest reason for this is that it sets up a storm path along or just off the Eastern Seaboard, and even with fluctuations in depth of the trough, a surface and low level northwest flow sets up straight out of Central and Northern Canada. While the supply of anomalous cold would run out (to some degree) after two weeks of this and have to rebuild, this takes us to the beginning of December, and who needs anomalous cold then - it's cold enough! But, yes, this pattern that sets up through the end of November means we're likely to see a series of coastal creatures that can be hit or miss from the first one in question early next week, through the last week of November. And yes, the difference each time is that cold air is better established, not thanks to a strong low level Canadian high, but more thanks to repetitive shots of northwest winds behind low pressure bringing in cold. This is not a dense and long-lasting cold, but when the shots keep coming, I would contend that there's only so many rain or mix events you can have until you're getting mostly snow events...or watching the storms barely miss offshore. So things will get exciting for meteorologists...and whether it looks like it or not, it will feel like winter for most of the public here in the Northeast for the end of November.
Enjoy your day.
Matt
