After a nearly 3 week stretch of weather dominated by limited moisture and rainfall, the pattern is changing and will become conducive for heavier precipitation later in the weekend and early next week. A preview of what's to come was experienced Tuesday in parts of my area when showers and storms dumped up to 2" of rain in localized spots.
You can see on the satellite how the jet is now aligned from the southwest drawing moisture into the central U.S.
A pronounced trough over the west and ridge over the east have set-up the moisture tap. PWAT's (available water vapor) climbed to 1.3" Tuesday in SE Iowa. That's high for late October.
The baroclinic boundary (the dividing line between cold and warm air) will sharpen over the weekend. A closed low is forecast to form at the 500mb jet stream level Sunday.
This appears to be the first of two disturbances that will act as precipitation triggers Saturday night through Monday night. You can still see the energy lingering over the central U.S. Tuesday morning as it gets ready to eject northeast.
In expectation of wetter weather the Climate Prediction Center has issued this 6-10 precipitation outlook.
One big issue models are struggling with is the amount of phasing that takes place over the weekend. The preferred solution right now (supported by the EURO ensembles) is for one strong disturbance to move through Saturday night and Sunday. You can see it here.
After a short break what should be a stronger storm takes aim on the area Monday. This is the one that has the potential to really rev up depending on the degree of phasing between the northern and southern jets. Monday nights EURO cranked out a powerful storm with dynamic cooling and widespread snow. The latest runs are weaker and warmer with little if any snow in my local area. We'll see how trends develop in the next couple of days as data is better analyzed out west.
As it stands now much of the area appears in line for 1-2" of rain Saturday night through Tuesday. Here's some of the precipitation forecasts.
The Weather Prediction Center.
Meantime, in advance of all this weekend mess, skies will break out today and temperatures should climb to seasonal levels in the mid to upper 50s. The screaming message, it's going to be a BOO-tiful Halloween day. Roll weather...TS