UP, UP, AND AWAY...
Another dreary day has come and gone but at least temperatures in all locations were in the 70s. If it's going to be ugly, it might as well be mild. Speaking of mild, these are temperature departures around the region since the beginning of September. Everybody running 3.5 to 6 degrees above normal on average temperatures.
October is really off to a toasty start with readings in the Quad Cities on average running a good 10 degrees above what's typical. I see that Des Moines has not had a high below 70 since May 30th. Thursday will be 130 consecutive days crushing the old record of 125 set in 1977.
Not only that, it's been very dry with much of the area running rainfall deficits of 2-3 inches over the same period.
It certainly looks as though we are going to sustain the October warmth for at least another two weeks. Look what the MJO (Madden Julien Oscillation) is forecast to do. It makes a swing through phases 5 and 6 which are both warm. However, phase 6 is particularly robust with well above normal readings covering the entire central U.S. during the month of October.
The overall long range pattern leads high confidence to continued warm weather with the mean trough anchored over the western part of the nation. In the animation below you can see the propensity for the western trough to continually eject energy and then reload quickly in its wake. Assuming the MJO and the models are correct, there is little chance for cold air to get into the region. Any cool-downs will occur in brief interludes.
Over the next 10 days the GFS shows above normal temperatures for most of North America east of the Continental Divide.
The next 7 days, the GFS indicztes the average temperature departures at +12-13 degrees per day through the 13th.
The following 7 days they cool some but are still very substantial running about 8 degrees above normal per day October 13-20th.
Needless to say, we've got some warm temperatures in our future. The one thing that remains a little uncertain is the position of the mean trough. Out 2 weeks it's tough to really dial in on the precise location but the Midwest is certainly in play and hopefully we get in the right spot to put a dent in this nasty dry cycle. Time will tell. Below you can see the precipitation departures indicated by the GFS and EURO over the next 15-16 days.
The GFS (16 days)
The EURO (15 days)
Getting back to the here and now, the big issue through Thursday night is how much rain falls from the cut-off disturbance that's lifting north our of Arkansas. A couple bands of energy will rotate around the center enhancing lift and precipitation. However, the rain is likely to be tied to scattered bands that spin around the low. The banded nature of the rainfall could mean that amounts will vary quite a bit over short distances. I also want to stress that the rains will be occasional mixed with some drizzle at times (not a washout). Models have been a little inconsistent with rain totals and the GFS for the most part is lower the past 24 hours and further east. The EURO remains quite bullish but is not quite as wet as earlier runs. The WPC blend is more consistent and lower than both models and I feel considering the pattern and need for rain may be closest to reality. I will lean that way and hope it beats me on the high side. We really need the moisture! Overall, my thinking is that most amounts will fall into the range of 1/10th to 1/2 inch. Here are the totals for the entire event. If there is an area that's most favored for the heavier rains it's roughly from the Mississippi River east.
The WPC blend
Friday the disturbance opens up and lifts out of the Midwest. That will lead to improvement and another dose of warm temperatures this weekend. Saturday with some sunshine should be very warm and still looks to me like a day in the low to mid 80s. Windy though with gusts to 30 mph. Sunday will be a bit cooler but still well above normal by October standards with highs upper 70s to low 80s.
Another fast moving system enters the region late Monday or Monday night and that brings a respectable chance of rain. That's the next focus after what appears to be a very fine weekend. Roll weather...TS
COMING UP IN FRIDAY'S POST...
I also want to mention that my winter outlook will be out Friday morning. There's a lot of speculation going around that a decent winter is brewing. I'll throw my hat into the ring and see what I can do to sway you one way or the other. Right or wrong, I put a lot of work into it and I hope you will find it interesting and informative. Here's to plenty of white gold and a white Christmas. It's been awhile.