Thursday, 11:55 A.M.
SO, you think it's cold out. Well, it is. And it has been. Temperatures from New York state westward to the eastern Dakotas are below normal for the month to date, and around the Great Lakes and Ohio Valley, that departure from normal is in the 3- to 6-degree range on average. We suffered through the severe arctic outbreak back on January 7, and record low maximum temperatures were set on Wednesday in parts of Kentucky, Ohio, Virginia, West Virginia, North Carolina, Maryland, Delaware, Pennsylvania and New Jersey. There's even some snow and ice in the forecast across Texas from San Antonio to Houston over the next 36 hours as the low-level cold is overrun by moisture from the south and southwest.
There's a bitterly cold air mass in place now from the Plains to the western Ohio Valley behind the weak wave of low pressure that has moved from Michigan into northwestern Pennsylvania this morning. The lowest temperatures as of 12z this morning:
Behind the cold front crossing the Midwest tomorrow night, another blast of bitter arctic air will move into the region. That frigid air will sweep across the Lakes and Ohio Valley Saturday, and into the mid-Atlantic states and New England Saturday night into Sunday. The core of the coldest air will actually pass north of the Lakes and by northern New England, but it will still be much below normal in much of the Midwest and Ohio Valley to the mid-Atlantic states. Here's a look at the 6z January 23 GFS ensembles 2-meter temperature anomalies for Sunday:
This cold air mass, though, won't get very far south. In fact, still another wave of low pressure will move out of the Midwest and across the Lower Lakes late Saturday night and Sunday. The latest model guidance brings that low to near Detroit Sunday evening. The 12z January 23 NAM surface forecast:
As stated in yesterday's post, this storm is going to perform much more like a classic Alberta Clipper. Determine the track, and most of the snow will be on the cold side of the arctic boundary, and generally north of the track of the storm itself. It looks now as if that will include portions of Minnesota and Wisconsin to maybe northernmost Illinois, then across Michigan and perhaps northern sections of Indiana and Ohio into northern Pennsylvania and Upstate and then central and northern New England. Expected snow amounts in the heart of this storm will be in general 3 to 6 inches with locally higher amounts.
What follows, though, is a really cold air mass! A 1047mb high will move into the Dakotas Monday night, pushing the bitter air mass well to the south. Here's the latest 850mb temperature forecasts for Monday morning:
By Tuesday evening, the frigid air mass will have plowed through Texas and off the Gulf Coast into Florida:
Chicago will likely get two consecutive days with temperatures failing to reach zero, and there could be one in Detroit, too. Look at the projected temperature anomalies for Tuesday:
That same massive high moving into the Dakotas Monday will find its way slowly to the lower Mississippi Valley and Tennessee Valleys on Wednesday, and it will represent a very stable set up. In other words, the coldest air will be in the low levels of the column, as is the case with arctic air masses, the air being so cold and dense. Up above there will be a temperature inversion, with somewhat warmer air starting to show up at midweek on the Plains, spreading slowly east the rest of the week. With that strong inversion in place, though, mixing of any of that warming down to the surface will be very slow at first, given the low sun angles.
Quite honestly, it will likely be the coldest three-day stretch of weather seen in a long time from the eastern Plains to the Appalachians, if not the East Coast. On can only hope that Punxsutawney Phil fails to see his shadow on February 2, but I highly doubt that will happen. The cold will begin to ease in early February, that seems likely, but I wouldn't be planning on digging out the summer shorts just yet.
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