RUNNING LIKE A RED DOG...
After a delightful day Tuesday, the rain machine is fired up and running like a red dog. Showers and scattered thunderstorms punched their ticket again Tuesday night and will be roaming the area through much of Wednesday. This will be a progressive event but because available water vaper is high (with PWAT values up to 1.25 inches), some areas are likely to see moderate to heavy rain totals.
As I stated, the high moisture levels lend themselves to pockets of heavy rain which will be defined by banding tied to frontogenetic forcing. Overnight the system kicked up a mesoscale convective complex (MCS) in southwest Iowa that has turned southeast with its heaviest rain just clipping my southern counties. A secondary round of forcing is shown impacting much of my area when it arrives Wednesday. General amounts of 1/4 to 1/2 inch look likely but there should be a band or two where amounts of an inch or more occurs. Some models are hinting at the northern half to one third of the region as being the most likely spot to pick up the heavier rains Wednesday. It will be interesting to see how much the overnight MCS disrupts the moisture flow as it passes to our south. I've seen occasions where that robs water vapor from the atmosphere further north decreasing rain totals where my area will be situated. So far models are not showing that trend but it is a potential negative. As a result, I'm not real comfortable picking any region as a focus for the heavier rains and potentially amounts could end up lighter than guidance indicates.
CAPE (instability) is also limited so thunderstorms will not be severe and perhaps not even found in some areas. However, those that can fire will be efficient rain producers hence the heavy rain threat in spots. Here's the projected CAPE at 10:00am Wednesday.
This is what models are suggesting for rain totals late Tuesday night. Still quite a bit of range in solutions.
The 3k NAM
The 12k NAM
With Wednesday's system long gone, Thursday promises to be a dry and pleasant day. With considerable sunshine highs should generally be in the mid to upper 70s. A keeper.
Friday is up in the air as the EURO promises mainly light showers that are most concentrated in the southwest. The GFS however brings another round of wet weather right through the heart of my area. I wonder if the GFS may be too aggressive with precipitation and too deep with it into my local area. Suffice it to say there is low confidence in this event but to me the better rain chances Friday will be confined to the area southwest of the Quad Cities. It may be that my northeastern counties see little if any rain. Here's what the EURO shows....
The GFS on the other hand drills my central counties with another soaker. For now, I have doubts about the magnitude of this scenario.
Over the weekend a warm front begins to inch towards the central Midwest from the south. It's possible a few showers or storms could clip mainly the north Saturday night as warm air advection kicks in there. Most of todays new guidance keeps the majority of the weekend dry and temperatures will begin to slowly climb. Highs Saturday should reach the upper 70s north to low 80s south. Sunday as the warm front makes its push highs should get into the range of 82 north to 88 south.
SOME SUMMER SIZZLE
There's serious indications that early next week summer is going to come blazing into town on a freight train. As mentioned in recent posts a stout heat dome is forecast to expand over the Midwest centered around a 595mb high over Illinois.
That produces a couple days of heat, especially if you buy the EURO's idea. It shows highs Tuesday and Wednesday around 100 in southeast Iowa. Mid to upper 90s are shown elsewhere.
Those readings are about 20 degrees above normal at the time of year when norms are closer to 80.
Even worse, the EURO depicts dewpoints in the low to mid 70s which would get heat index values above 100 degrees which would warrant heat advisories or warnings if this whole set-up verifies.
I will stress that the GFS does not show the intensity of the heat that the EURO does. It also does not last more than 2-3 days on either model. That said, even if it ends up a few degrees cooler, early next week looks like a hot tamale for the central Midwest.
After Monday the atmosphere looks capped inhibiting thunderstorms near the ridge core for a couple days. However, with time we may get into a more favorable pattern for some ridge riding thunderstorms. If we do, and can break the cap, instability will be proficient and robust thunderstorms would be the end result. Somebody will likely experience such a thing but when and where is a question that can't be answered at this distance.
All in all, there's plenty of weather on the table and the forecast will be highly changeable from day to day through Tuesday. Sounds like fun to me. Happy hump day and roll weather...TS