RIDERS ON THE STORM...
The past 24 hours Midwesterner's have been riding out a potent November storm that is tracking directly through eastern Iowa. Showers and thunderstorms have been active with with many places in eastern Iowa and NW Illinois on the hook for 1-3 inches of rain before the storm spins its way into Wisconsin Saturday morning. Amounts while still appreciable, will end up lighter SE of the Quad Cities due to the effects of a dry slot just east of the storm center track. Here's what the National Model Blend indicated for rainfall totals...just a guide. We'll have a list of final amounts at the conclusion of the event.
Notice though on the surface depiction how the heavier rain band is focused just NW of the surface low track situated in SE Iowa near Muscatine early Saturday morning. Track is essential when it comes to mesocale details that determine precipitation impacts.
While it ain't necessarily pretty, the rain was a huge blessing for much of the central Midwest. It was especially welcome in Iowa where the entire state is abnormally dry and 81 percent is in either moderate, severe, or extreme drought.
Here in Dubuque we received more than an inch of rain on a calendar day for the first time on 88 days...almost 3 months! We had a pretty good little thunderstorm too. Below you can see the impressive satellite representation revealing the deep feed of moisture ahead of the 145kt upper level jet feeding in from the SW. Love it!
What's left of the rain will diminish from south to north Saturday morning as drier air swings in behind the surface low and attendant cold front. Blustery W/SW winds may reach gusts over 40 mph as a rapid pressure rise follows the front. Temperatures will start mild early Saturday with 50s west of the Mississippi and low 60s east. However, the strong winds will drive much colder air into the region in the afternoon with readings back in the low to mid 40s in all areas by early afternoon. Some spotty light showers or drizzle is also possible in the afternoon but the heavy rain is done.
Sunday significant improvement is anticipated ahead of a weak cold front approaching from the NW. Highs will reach into the upper 50s to low 60s with at least partly sunny skies. As the front passes Sunday evening winds will turn to the east and finally the SE Tuesday. That should drop highs into the low to mid 50s Monday and mid to upper 50s Tuesday.
By this time the western trough is reloading creating another formidable trough over the Rockies. That means it's time for a warm-up with readings into the 60s both Wednesday and perhaps part of Thursday. However, as energy rounds the latest trough it appears a strong cold front will sweep the central Midwest with renewed chances of showers and a few thunderstorms, much like we are seeing now. That's followed by sharply colder temperatures next Friday.
If my theory is right, this is the point that the EPO starts to do its dirty work entering a strongly negative phase which suggests significant ridging over the eastern Pacific. That teleconnects to a pattern that would allow colder air to push over the central U.S.
The developing negative EPO the next 2 weeks.
The GFS shows the expected response with much of the nation well below normal during the 10 day period November 10-20th.
The weeklies of the EURO indicate the EPO remaining negative through December 18th which certainly would lay the foundation for a quick start to winter.
The weeklies indicate this for snowfall through December 18th.
With regard to the weeklies, I can only say that nobody (including me) expects a 6 week forecast to be perfect. That said, the trend is your friend until it isn't. I think the weeklies have merit considering the blocking I'm expecting at high latitudes, sea surface temperatures, La Nina, and a warm AMO (Atlantic Multidecadal Oscillation) that's tempered by a colder MDR (main development region for hurricanes in the tropical Atlantic).
As you can see below, warm Atlantic Sea Surface temperatures paired with cooler ones in the main development region of the tropics, (combined with a La Nina) correlate to cold winter temperature patterns over the NC United States .
We will know soon enough. Enjoy the rest of your weekend and as always, roll weather...TS