Interesting post on the homepage about California snow. Also, Winter Sports Page has been updated with new stuff yesterday and today so worth checking out if you're heading north.
Weatherwise, an arctic cold front slowed and has nearly washed out across New England on Thursday, though a wind shift is still evident, and deeper cold air will build into the region Thursday night through Friday. The cold will reach its peak intensity only briefly on Friday, but will be quite stubborn in its departure over the weekend, resulting in plenty of clouds and some periods of light snow. Eventually, a brief moderation in temperature is in store for the Northeast by early next week, though it won't be as pronounced in New England as the warmth will be from the Ohio Valley to the Mid-Atlantic.
For now the arctic front moving across New England has largely
outrun the best push of northwest wind, meaning it's lost its impetus to
charge much farther south, slowing dramatically over Southern New
England. With such a slow moving front, the convergence of air in New
England means rising air - favorable for cloud production so that
clouds will continue to outperform sunshine Thursday, and scattered snow showers
and flurries are likely to continue from time to time. Much like summertime showers, daytime heating and a fast wind aloft will couple to favor stronger snow showers and even some heavier squalls later Thursday afternoon and evening, and temperatures either side of freezing will pose a threat for quick icing of roadways where heavier squalls fall. Of course, you can follow these squalls via the radar links to the right of this discussion.
Meanwhile the deep feed of Pacific Tropical Moisture and Gulf of Mexico moisture
continues to stream across the Southeastern United States and off the
coastline, teaming with energetic disturbances aloft to breed an ocean
storm Thursday afternoon. This storm will stay southeast of New
England, but will force the push of cold air to continue to move only
very slowly until the storm circulation has passed to our south and
moved east of our longitude, allowing the northwest flow of air to
increase once again and thereby carrying deeper cold into New England
on Friday. By that point, however, the atmospheric pattern will be
quickening, and this will hasten the eastward migration of deep cold,
meaning the shot of new air cold enough to support high temperatures in
the teens for many areas with wind gusts to 35 mph and chill values in
the single digits to around ten on Friday afternoon beneath a blend of sun and
clouds, will give way to advancing warmth rather quickly after
emphasizing its one day point of cold.
With the onset of warmer air on Saturday, the typical collision of
airmasses will establish overhead, and that will mean gradually
increasing and thickening clouds. By Saturday evening and night, the
passage of a weak disturbance aloft, at the jet stream level, is likely
to mean at least a period of poorly organized light snow that may last
into early Sunday. Certainly, a pattern like this is worth watching
closely because it won't take much extra work to ingest some Gulf or
Atlantic moisture into the mix here for heavier precipitation, but at
this point it continues to look like the deeper moisture remains to our
south and east this weekend. This would allow milder air to be in
place on Sunday, with clouds trying to break for the afternoon and
temperatures responding by rising above freezing for most spots in Southern New England. The farther north one is on Sunday, however, the more clouds will linger, as the upper level wind pattern will still feature a stubborn trough in place, meaning energy and cold air will linger aloft, and that favors cloud production. In fact, if the upper level trough lines up perfectly with a moist disturbance missing New England to the southeast, a weak Norlun trough is a possibility along the Maine coastline - especially between Casco Bay and the Midcoast - Sunday afternoon. Remember that a Norlun trough is a weak disturbance, usually characterized by a wind shift, that sits beneath an "unstable" atmosphere, meaning one that's primed for bursts of snow. When conditions match up at the surface and aloft, continued bursts of snow can occur in a narrow area, and cause quick accumulations. At this point, that possibility is just that - a possibility - and I'll continue to keep an eye on it.
Indications are that the warmer air will continue to ride our way
through early in the week as a storm center develops to our west, and
the counter-clockwise circulation of air around it favors a southerly
or perhaps southeasterly wind. In fact, the exact direction of the
wind will be quite important in just how warm New England is on Monday
and Tuesday, as the cool ocean waters would imply that any wind off the water is going to be a significantly tempered warmup - but still into
the 40s - while a due south or especially a southwest wind would mean a
more significant thaw. At this point, the pattern seems to be slowing enough that a northeast wind actually may linger all the way through Monday, then slowly come around east and southeast Tuesday and Wednesday, leading up to a Wednesday cold frontal passage. A persistent northeast flow would hold plenty of clouds in coastal locales on Sunday, with an easterly wind perhaps still holding clouds on Tuesday for some eastern communities, though the airmass would likely gradually moderate with an exhaustion of deep cold. If the cold front on Wednesday is late enough in the day, it may briefly usher more
substantial warmth and a southerly wind into New England just prior to
cold frontal passage, but that timing will become clearing as we near it. Behind the front, another shot of cool air would
settle in with below normal temperatures for several days.
Make it a wonderful Thursday.
Matt
