HEADING TO THE FINISH LINE

It was another cooker Thursday with near record Aprils highs in the 80s. In many spots it was the 3rd consecutive day with warmth of that caliber, a tough feat to accomplish before April 14th. Unfortunately the end is in site but not before another fine day Friday. As the saying goes, all good things must end.

The process of change begins with the break down of the blocking pattern that's been in place since Monday. As it does, systems can start moving again and by all accounts it seems as if we are headed into an active pattern going forward that will feature plenty of temperature swings. Watch in the animation below how the warm ridge gets knocked down and a cold unsettled trough builds in for the second half of the weekend. So long 80s, it sure was nice to meet you!

Synoptically, the transition involves a cold front and wave of low pressure that slowly emerges off the high Plains Friday and Saturday. Southwest flow finally taps into some moisture at the low levels. The process really doesn't occur in earnest until Friday night but by Saturday, dew points are nearing 60, a nice jump from the mid to upper 40s of Friday morning.

That ultimately increases available water vapor (PWAT's) to values greater than an inch, a healthy level.

The cold front approaching from the west has slowed a few hours from previous runs and that allows another day of very mild temperatures with highs hitting the low to mid 70s.

The combination of warmth and newfound moisture leads to respectable instability and CAPE for scattered thunderstorm development, especially later in the afternoon.

The limiting factor for widespread severe weather is a lack of shear. A few updrafts could produce some hail and gusty winds and SPC notes that with a marginal risk of severe weather (level 1 of 5). Some areas certainly could see some brief downpours where thunderstorms occur.

ONE HOT DEAL... 3 NIGHTS FOR THE PRICE OF 2 MEMORIAL WEEKEND IN GALENA

THE LITTLE WHITE CHURCH AWAITS YOU

Get the gang together. Kick off summer with a free night at the church, one of the most unique stays in the Midwest. Call Carolyn at 563-676-3320 or email carolynswettstone@yahoo.com CLICK HERE

IT"S SNOW JOKE, WHITE GOLD RETURNS TO THE FORECAST!

The most challenging aspect of the weekend to forecast is the potential for wet snow to fall in some part of the Midwest. Recent guidance has come in more bullish on that potential wrapping in cold air and rain as a low pressure wave forms along the cold front near or just east of the Mississippi River early Sunday. Not only does this increase precipitation totals, it pulls enough cold air in to change rain to snow (or at least a mix of rain and snow) before the storm departs. Aside from the usual problems with timing any transition, the late season nature of the event will make it difficult to snow unless precipitation comes down fast and furious enabling efficient evaporative cooling. I've seen it happen a few times this late in the year resulting in some decent slushy accumulations. if it happens it won't be around for long. Currently, its the NW half of my area that has the greatest threat of seeing the flakes. Models hold off on any snow until Sunday afternoon or night.

We have some details to sort out regarding snow but I think it's becoming more and more likely that some parts of the central Midwest will see accumulations, especially Sunday night. This certainly needs to be watched as these late season storms can do some wild things. Just to show you I'm not off my rocker, here's what a few models are suggesting for slushy snow accumulations. This is just raw model guidance and far from a sure thing but the trends have grown stronger the past 24 hours. FYI, I would highly doubt the extreme amounts the GFS shows.

The GFS

The EURO

The NAM

Precipitation which certainly begins as rain before any transition occurs looks significant. Here's the projected rainfall totals Saturday-Monday.

The GFS

The EURO

The NAM

After one last mild day Saturday, temperatures start our Sunday relatively mild but will take a significant tumble Sunday afternoon falling into the 30s north to the 40s elsewhere by evening. Sunday night readings head for the low 30s, especially where snow falls.

Monday is shaping up to be a fresh day with highs in the upper 40s north to the low to mid 50s south. Tuesday 55 to 60 looks good and Wednesday showers and storms return with highs back in the 60s, maybe 70 far south.

I will also add that new forecasts indicate a 50 percent chance or greater odds of major flooding on the Mississippi

River from Dubuque to Burlington in coming weeks.

The 2 week rainfall forecast on the GFS will not help the situation if indeed it verifies.

Well, there you have it, a forecast with everything but the kitchen sink. Enjoy Friday, we are approaching the finish line for these amazing temperatures. Roll weather...TS

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