A Thaw Then A Blast!
Well this will be our January thaw week, which it seems we usually have every year during January. Last winter of course, the whole winter was a thaw, then it seemed the two previous winters before that, the thaw, sort of skipped by us since it was so cold and snowy, so let’s enjoy this week, because while the details are still somewhat muddy, it does look like a prolonged period of cold weather will be moving in towards the end of the weekend.
Temperatures this week will be running 10-15° above average as a storm moves and gets cut-off across the far SW part of the US and into Old Mexico. See my previous blogs for more on that since there really are no changes to my thinking concerning the rain chances on Thursday. At this point I’m not expecting a lot, even though the storm should come right on top of us, or pretty close by. Here is the GFS forecast for the storms location on Thursday.
By then rain should have moved into the area from the south and SE, spinning around our storm system. The problem is also by then the storm’s circulation will be large and the rainfall will be flung across a broad area of the region, such that the rain will move in and then move through the region as dry air wraps around the storms circulation. How this potential dry air messes up our rain totals remains to be seen, but at this point I’m still thinking this event will give us 1/2″ of rain or less.
Here is the GFS model again showing the storm at about 10K feet…notice the higher humidity levels at that altitude (in green) in E>W bands…also notice the dry air working into and through the circulation at that level as well…when that dry air wraps into our area, the decent rain will shut down and lighter rain/drizzle will be possible, along with some clearing?
Something to be alert about, depending on how the day evolves, should we get some clearing and temperatures warm up enough, the atmosphere will become unstable and the potential for some small t/storms will be there, maybe even some small hail producing cells as well since the freezing level will be about 8500 feet or so…again that opportunity is dependent on some clearing making things unstable enough (maybe SE of here?).
The storm, since it’s cut-off from the northern jetstream this week, will not really have any Canadian cold air behind it, so as a result we should again warm-up on Friday ahead of our next storm that will have Canadian air behind it. That will move through the area sometime over the weekend. A few days ago the models were suggesting that Friday would be the transition day, now it’s sometime very early Saturday and I wonder, since they have a tendency to speed this stuff up to much, if it will get pushed back a little farther. Regardless a strong front will push through over the weekend!
This front will certainly usher in colder weather, but there are still some questions about how cold and for how long. The GFS is certainly banging the drum on some VERY cold Canadian to eventually Arctic air to barrel through the region starting over the weekend, and lasting for almost the rest of the month, if not into February.
The EURO on the other hand, while delivering cold air into the region, is still not bringing the motherlode of cold through our region. So some conflicting signals are still there. The NAEFS which is a large ensemble run of models is not exactly brutally cold for next week. There are cold chunks of terrain out there, notice up towards the Great Lakes in Canada and in the southern part of the country…but for us…not as much.
Just for the heck of it, here is a look at the temperatures at the surface, forecasted for NEXT Monday @ Noon...based on the GFS model at least.
Odds are our highs that day, just based off the model would be somewhere in the 20s. again cold for sure, but not unusual for Mid January. You can certainly see a lot of sub-zero weather across the Northern Plains region and the Northern Rockies. The EURO on the other hand still gives us highs in the 30s for MON-WED of next week.
So IF nothing else, the players will be on the table with this set-up. the potential for colder weather continues to increase but the degree of cold and extent are still up for discussion.
One final note…there is some potential of another storm (after Thursday’s storm) with all these contrasting airmasses in play. It would be a storm that would usher in the Canadian air over the weekend. What type of precip and when are undetermined, but I would be surprised if at least some sort of storm didn’t develop with all this going on.