The chances are increasing that we may see a wintry event across the area on Thursday. The models have been showing this threat now for a few days, but as I mentioned on Friday, there was still enough uncertainty to not feel strongly one way or the other on the chances of this happening.
But now we have seen consistency from the GFS and the ECMWF for the last several runs in showing a light overrunning event, where cold air at the surface remains locked in as warm air aloft streams in from the southwest. This type of weather pattern produces abundant cloud cover and several periods of light precipitation. In the winter when you have a cold high pressure to the north and/or a very cold, dry air mass in place before the precipitation begins, you can have precipitation type problems, and that may be the type of setup we are heading towards.
The air that will move in later today behind this cold front will be very cold and dry. Dewpoints will crash down to near 0 and temperatures will struggle to get into the 30s the next couple of days. The cloud cover and moisture will increase Wednesday night, and we will likely see strong evaporational cooling occur as the precip begins which should drop many areas below freezing during the day Thursday.
As of now, it looks like this will not be a heavy precipitation event, but we could see a 0.25 to 0.5 of precipitation that could fall in the form of a wintry mix anywhere from Thursday morning through Thursday night. So Thursday is certainly a day to watch out for.
The mountains are also going to see an extended period of snow and 6-12 inches are possible in some areas.
The models are also hinting at the possibility of another wintery storm sometime between Sunday and Wednesday. The 12z ECMWF from yesterday showed this happening Saturday night, while the 00z run now shows it happening Tuesday night. The GFS hadn’t shown much but the 6z run now shows it occurring a little too far off shore on Saturday night. Many of the ECMWF Ensemble members show it happening on Sunday.
So there is considerable uncertainty with that event, but confidence is increasing that we may have some wintry precipitation around on Thursday, although the details are still not clear.
As far as today goes, a line of rain will move through and then we will see the temperatures fall very quickly later this evening and the winds pick up. Temps will likely be in the low to mid 20s by tomorrow. A scattered snow flurry is possibly this evening as well.