Good Monday and welcome to the first full week of December. Spring is in the air on this Monday as mild temps and scattered showers dominate the day. Snow and cold lovers across the country are left out in the… mild. Most are probably thinking here we go again. Well… hang tough. The change toward winter continues to show up very strongly later this weekend into next week.
Let’s start with the mild present. Temps today will be well into the 60s again and a 70 is possible… especially across the south. Scattered showers will be noted with a rumble of thunder possible.
The first of many cold fronts over the next few week shows up by late Tuesday. This front will spark a line of showers and thundershowers that rolls eastward across the state. Locally heavy downpours will be likely by the late afternoon and evening hours. Winds will be gusty and temps will come way down behind this front. Highs Wednesday and Thursday should stay in the 40s for many areas.
As you know, I’ve been targeting the period of December 7th-14th for a big change in the pattern that will lead us into winter. There is little doubt the pattern is going to drastically change during this period and will likely set the stage for several shots of cold and snow threats for the middle and end of the month. Take a look at this snippet from the HPC extended forecast discussion:
MODELS AND TELECONNECTIONS
PREDICT DEVELOPMENT OF A BROAD SCALE POSITIVELY TILTED
TROUGH…SUPPORTED BY INTRUSIONS OF ARCTIC AND MODIFIED ARCTIC AIR
INTO THE CENTRAL/EASTERN STATES.
They are now sniffing out this huge pattern change to a deep trough across our part of the world. Once that gets locked in, it should stay there through Christmas. The only real question I have is, exactly how does this trough get established? That’s the real question to tackle this week and I’ve been doing a lot of research on similar changes during December and one thing stood out. Most of them had to go through a lot of rain to get from the mild start to the wintry stuff.
This coming weekend looks wet around here as our trough slowly digs in across the middle of the country. This causes a front to slow down across the Ohio Valley by Friday. Waves of low pressure will ride northeastward along this boundary and that should allow for rounds of locally heavy rain across this region. That’s a good thing because we are getting pretty dry again.
The series of lows should feature the final one as being the bigger of the bunch and feature more of a wintry aspect after it passes by. I suspect that low will track over us or just to our west and could result in a huge temp jump and dive. Timing these waves of low pressure is an impossible task for the models and they will feature some wild swings in the coming days.
Again… I’m only talking about timing and placement of the lows this weekend and NOT the change toward a wintry pattern. I showed you a series of 500mb maps from the European model with my last update and that still looks good through next week. To illustrate this thing likely locking in… check out the GFS Ensembles 500mb Height Anomalies even farther down the road…
Buckle up for the ride into winter… it’s gonna be bumpy one. 😉
I will update things later today. Have a great Monday and take care.