Between the senseless gun slaughter in Las Vegas and the death of Tom Petty ( a dude on my playlist many times over) I was in a pretty foul mood Monday. It wasn't until after the models came in with some big rain numbers that I finally got my mind in a better place. Thank God for the weather, it always gets me through....(TP could have made a fine song out of that).
This coming wet weather I'm referring to involves 3 systems in a short period of time. The first (already soaking western Iowa and Minnesota) hits my area Tuesday night. Another ripples through Thursday and the last but not least "big kahuna" hits Friday. The 3 events combined result in rain totals in the 1-3" range. Here's the EURO rainfall forecasts:
Now the 18Z GFS. Note that both models have over 3" in Cedar Rapids and the GFS has 5" on the 0z run for the Quad Cities.
The storm that I'm most interested in is tied to a surface low that runs from the Plains into Iowa Friday. The GFS is deeper on the pressure and further northwest than the EURO but it doesn't seem to impact the end result. Here's the EURO's depiction of the surface features Friday evening.
To get widespread significant rain you need moisture and that's one thing this system will have plenty of. Here's the PWAT's (precipitable available water vapor) forecast by the EURO. Amounts of up to 2" are common.
PWAT's that high this time of year are about twice (200%) what's normal.
While there is some respectable shear the amount of CAPE (convective available energy) appears limited. For that reason the severe weather threat seems low but that needs to be watched. As of now, the Storm Prediction Center does not have any severe risk in its day 4 Friday outlook. It does show this for Thursday day 3.
As the first round of energy arrives Tuesday the associated cold front will create a decent temperature contrast from west to east across the Midwest. The EURO has this for highs.
Once the front passes Tuesday night temperatures will cool throughout the Midwest and by Thursday readings will be as much as 20 degrees cooler than what we see Tuesday. Finally, some weather to get into. Perhaps even a drought busting wet period! A bright spot in an otherwise dark day. Roll weather...TS