THE NEXT STORM UP....
A vigorous fall storm worked its way over southeast Iowa Monday delivering showers, thunderstorms, and some much needed rain. Here's a radar estimate of how much rain fell Sunday night through Monday evening. Many places had an inch or two but there was that one little area in EC Iowa that underperformed. That's disappointing as that is the spot that needed it most.
This tighter perspective shows amounts in my area Sunday through Monday morning at 9:00am
With Monday's system on the way out, the next one is fast on its heels. The later digs into the four corners Tuesday and then rides the sling-shot northeast as a very dynamic storm Wednesday. You can see the pair separated by fair skies over the Plains in the satellite image below. That's the sunshine we'll enjoy Tuesday. Toss in temperatures in the low 70s and you've got yourself a keeper.
At 500mb you can see the impressive trough that's finally brought moisture and enough forcing to get the rain machine started locally. You can also distinctly see the energy in Nevada that drives our next rain chance Wednesday.
At this point there are two windows open for precipitation from this disturbance. The first is driven by warm air advection Wednesday morning. Scattered showers and storms are likely thanks to this wave of forcing. The second window is associated with cold air advection and a punch of dry air that arrives late afternoon or evening along a cold front. While the surface low and triple point are well north of the region, there's a nice punch of mid level dry air and healthy shear. Moisture looks plentiful with dew points potentially reaching the upper 60's. Below you can see the dew points in the upper 60s near the Mississippi while in western Iowa they are 30+ degrees lower in the mid 30s.
With late day readings in the mid to upper 70s indicated, that should generate at least modest instability and perhaps a short window for severe weather potential. The composite radar of the 3k NAM does indicate a broken line of storms crossing the river between 5 and 7:00PM.
The threat of any storms and associated severe weather later Wednesday is highly uncertain and muddled by a number of key variables such as timing and instability. Confidence is low that storms will even form, let alone whether they will be strong. In the end, the best prospects for rain may very well occur in the morning when a strong but quick wave of warm advection sweeps across the region.
Behind the front Thursday, skies look to clear and temperatures will turn cooler. Even so, highs in the upper 60s will still be above normal and it looks like a pleasant day.
Friday is a wild card right now with the GFS showing a scenario where another system ejects out of the southern Plains with widespread showers and storms. The EURO is much further south and just swipes the SE with some deformation showers. Either way, at the very least we are likely to deal with clouds. At the very worst, another round of potentially wet weather is possible. I'm not ready to pull the trigger on any solution yet until we remove some of the energy from the pattern later Wednesday. Mesoscale details from the dynamic mid-week system could play an important role in defining Friday's storm track. However, I like a drier solution and would not be surprised to see rain chances go way down on the GFS in coming days, especially in the NW 2/3rds of my area.
That will do it for this blog. Have a terrific Tuesday and roll weather.