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:
A series of strong Pacific disturbances will churn across the United States in the next several days. Meanwhile, shallow cold air continues to build across Southern Canada while the Northeastern United States sits under the fast jet stream winds aloft. Remember that these jet stream winds are the corridor of fast-moving air that steers our storm systems and acts as a thermostat for the atmosphere, separating cold air to the north from warmer air to the south. With this atmospheric thermostat running so close to New England, significant swings in temperature are likely over the course of the next several days. The timing of moisture with each shot of cold or warm air will determine precipitation type for each disturbance that moves through, extending out beyond the Christmas holiday.
Clearly, Monday's disturbance comes with enough mild air for raindrops in most areas. This upper level disturbance was zipping east through the day, and will move out of most of New England by mid-afternoon Monday, leaving most of Central and Southern New England under plenty of clouds, while Northern New England sees a continued blend of clouds and sun. The weather setup features a cold front sagging south through New England - draped over Central Massachusetts Monday morning - with cooler air gradually nosing southward behind the front, and mild air still in place in advance of it. A weak wave of low pressure along the front - the surface reflection of the aforementioned upper level disturbance - has helped to focus showers, and the passage of this wave and its associated upper level feature will help to yank heartier cold air southward from Canada. The result will be a freshening wind Monday evening.
Winds will remain quite active Monday night as a new, cool Canadian airmass spills south, dropping temperatures into the 20s for most locales and near 30 in Southeastern New England. Combined with 10-15 mph winds and a few higher gusts, these falling temperatures will help to produce wind chill values in the teens for many areas, making for a chilly night for those at work outside during the overnight. The shot of cool air will still be present on Tuesday, as temperatures struggle to rise out of the 30s in even the warmer locales, while thousands of feet above our heads an energetic disturbance will dive southeast across the region, prompting scattered snow showers through the day regionwide.
The jet stream winds - so crucial to the forecast - will coil and recoil over the course of the week, favoring a continued shot of cool air on Wednesday, and with a lack of any strong disturbances, likely plenty of sunshine mixed only with high altitude clouds. To our west, a deep storm will churn across the Central Plains and the counterclockwise flow around this storm both at the surface and aloft will usher moisture out of the Gulf of Mexico, and pull warmth northward, while cold air will surge south behind the storm center. The result will be an onslaught of warm and moist air aloft later Thursday, bringing increasing and thickening clouds to filter sunshine, but likely not a deep enough surge of moisture to produce any precipitation during the day Thursday as the primary storm center will still be located well to our west. Nonetheless, this storm will have left quite a mark across the Rocky Mountains, producing heavy snow in the foothills of the Rockies and even in Western Kansas. Gradually, this slow-moving storm will feel the influence of the strong westerly jet stream winds, and after meandering across the Rockies, will begin to lift northeast. The main slug of energy associated with this storm will move across the Great Lakes and into Southern Canada for the end of the week, but ahead of this storm the jet stream winds will orient out of the Gulf of Mexico, delivering first the clouds on Thursday, then a shot of precipitation on Friday.
Friday's precipitation - like the other events of the next several days - will hinge upon how much cold air is present, and just how long that cold can hold on. At this point, it appears to me as though the push of southern warmth will be too significant for wintry precipitation in much of New England - especially Central and Southern areas - while the mountains of the north, and especially the mountains of Northern New Hampshire and Maine, may hold onto enough cold air to receive some snow on Friday. By the time this disturbance moves into Canada and weakens, two important reactions will already be underway. The first is for a slug of cold air to migrate southeast out of Canada in the lower several thousand feet of the atmosphere and into New England for the upcoming weekend. The second will be for yet another strong upper level storm and its associated surface low pressure center to move across the Southwestern United States, the Rockies, and the Plains. This next storm will be one to watch, as it will move east into a trough - a dip in the jet stream winds aloft - over the Central United States that will favor continued development of this storm as it shifts east, pickup up Gulf Moisture. Because the jet stream trough is a dip in the winds, winds flow from the north, behind the trough, and from the south ahead of it. This is important, because it means any storms and moisture over the Southeastern United States later this weekend would be ushered northeast, pushed by these winds blowing from the south and therefore directed up the coastline. Once again it will be a battle of incoming warmth and moisture, and antecedent cold - should the cold hold on long enough, snow would be the result Christmas Day. Working in favor of snow will be a bubble of Canadian high pressure settling over Southeastern Canada over the weekend that will hold into ealry next week. When we examine all of these factors, it becomes evident that the ingredients are at least there for a Christmas snow that would certainly seem a miracle given the weather pattern of late. That said, I would caution one and all to take this as something that allows us to keep the fingers crossed, etc., etc., and I would urge everyone to use extreme caution when offered a blow-by-blow detailed account of whether it will be no storm, rain storm, snow storm, or otherwise. The honest answer here has to be that the atmosphere will be chaotic and will favor storm development with cold air nearby, but the level of interaction between Gulf Moisture and cold air will become clearer only with time. So...keep those fingers crossed and I'll see you back here and on NECN tomorrow.
Technical Discussion: Public appearance today, techie out tomorrow.
Matt
