Currently: A few lake effect streamers are producing scattered snow showers across the state. This will continue for a couple more hours, before winding down, due to the loss of daytime heating. If you like snow, enjoy it, because you won't see any more for at least a week.
Tonight: Coldest air mass for a while in full force across the state. Low temperatures will probably be within a few degrees of 30. There shouldn't be much fluctuation from one part of the state to the other tonight, since winds will stay up. Any snow showers diminish in a couple more hours with the loss of daytime heating.
Tomorrow: Sunnier and less windy than today, as high pressure moves overhead. Temperatures will be similar to those of today, or maybe a degree or two warmer. Highs will generally be just above the 40 degree mark.
Tomorrow night and Monday: Warm air advection commences tomorrow night, as the high pressure system shifts offshore. Because of this, temperatures will be three to five degrees warmer tomorrow night than tonight. A few 50 degree readings are possible. The warmest locations should probably be the southern valleys, but away from the immediate coastline. Although temperatures will be warmer on Monday, it really won't be all that much of a pleasant day, as onshore flow will mean lots of clouds.
Longer Term: On Tuesday, a cold front will approach the area, but die out before it reaches the area. However, it will probably come close enough to trigger some showers, or even a period of light rain, during the afternoon hours, across the entire state. Tuesday's air mass aloft is much warmer than that of Monday. However, with some rain occurring, temperatures will probably only be a degree or two warmer at the surface. Then, a storm system passes well to our west- moving into the Great Lakes. Rain from this system will overspread the region Wednesday night, probably just after rush hour in the Southwest, and a few hours later in the Northeast. Wednesday's temperatures will be quite warm, in the upper 50s, and may approach a few record highs. There is a batter chance of record highs on Thursday. Rain should end just after dawn. The rest of the day on Thursday should feature some intervals of sun and only widely scattered showers. Temperatures should soar well into the 60s. If this happens, this would shatter many record highs across the state. A cold front will trigger another band of showers Thursday night, for Santa's big night. Christmas Day should feature varying amounts of clouds, with temperatures still making it well into the 50s, as the air behind the cold front is of Pacific Origin. Saturday will be noticeably cooler, but still above normal, with highs into the mid and upper 40s. A litttle light rain is possible later in the day on Saturday, as some overrunning moisture- that is when warmer air rides over colder air at the surface and creates precipitation- moves in.
Here is a look at the high temperatures progged by the GFS model for Christmas Eve (Thursday):
Long Range Discussion: The end of December definitely looks to continue the trend that has begun to slowly begin, which is a trend toward stormier than normal. Temperatures also look to finish the month above normal. There is a storm system slated for somewhere around the 28th of this month. This storm MAY have some wintry threat with it. Given the fact that there is still a ridge in place, and the pattern we've been in, if I had to lean one way or the other, I'd go for a rainy scenario for the entire state. All in all, the pattern is not favorable for a winter storm yet at that time. HOWEVER, it really isn't cut and dried, either. There is more high pressure over Southern Canada in that timeframe than we have now. As you probably know, high pressure in Canada produces cold weather here. Most models slide the storm in between highs- that is, one high pressure system moves out, then another moves in, and the storm slips in between the two highs. This would produce a warmer, rainy situation, with maybe just a little freezing rain to start in the very coldest places. This solution probably makes the most sense, since there is no blocking up north to hold in the high pressure systems. However, we do have high pressure systems over Southern Canada, which means two things: First, the availability of cold air is increasing. Secondly, if the timing is off with this system, it could produce a significantly colder scenario. And of course, we're still nine days out, which means things are far from etched in stone. Beyond that, there is a coastal storm potential around or just after New Year's. Once again, availability of cold air would determine if this system was white or wintry, and timing would determine if this system came up the coast, or slid out to sea.
The overall long range pattern still favors ridging in the east, without much blocking up north. However, there are beginning to be signs that the ridge could begin to weaken and move north. This would set up more of a pattern of blocking up north, which would slow things down and have a tendency towards more high pressure in Canada. With the block not in a totally ideal position (at least not yet), the cold aiar would not be of pure Arctic origin, but under the right circumstances, it could still be cold enough to support winter storms.
Over the past few days, although guidance still shows a tendency for ridging over the Northeastern United States, there have been some model runs that have begun to show that ridging breaking down. While long range models are a decent tool to predict if a pattern is changing ( a week ago today, models were basically showing nonstop ridging over our area and no break in sight), models have a tendency to rush pattern changes, in both directions. Therefore, the if models show the pattern change in the Dec 25-30 time frame, you may see it manifest itself more in the January 5-10 time frame. This is something we should keep our eyes on now, as models are finally beginning to show the first hints of "instability" in the long range upper air pattern.
Stay tuned for more updates on the upcoming stormier pattern, the Christmas forecast, and the overall long range pattern!