Heavy Rain Threat Part Zwei

[wisconsinwx]

This is for those in Iowa, Minnesota, Wisconsin and Illinois in particular who may be seeing more rounds of heavy rain this Tuesday, Wednesday, Thursday and mainly Friday as a nearly stationary baroclinic zone hovers in the area.

[wisconsinwx]

12z GFS indicates the heaviest bands of convection will probably be over Northern Iowa, SE Minnesota, and Central Wisconsin at this point. I can see anywhere in N and C Iowa, C and S Minnesota, Wisconsin and N Illinois still being fair game for several inches of rain mid to late week.

[A-L-E-K]

My early (too early) guess is far southern Wisconsin or more likely northern Illinois, if only because I always hedge south of model guidance with similar patterns and at this range. Either way, whatever happens will be highly dependant on mesoscale interactions so not much sense getting to fancy now.

EDIT: too fancy, too fancy.

[wisconsinwx]

My early (too early) guess is far southern Wisconsin or more likely northern Illinois, if only because I always hedge south of model guidance with similar patterns and at this range. Either way, whatever happens will be highly dependant on mesoscale interactions so not much sense getting to fancy now.

Well, the last few GFS runs have ranged from Northern Iowa/Southern Minnesota to S. and EC Wisconsin, eventually putting N Illinois in one or two MCS' late Thursday into Friday. I think we have a better chance here than we did last week, but I might as well prepare for a similar near miss in case it happens.

How does the Euro compare to the GFS and NAM? The NAM is much less bullish, but I'm not sure whether to discard it, since it does a poor job in the medium to long range.

[A-L-E-K]

Well, the last few GFS runs have ranged from Northern Iowa/Southern Minnesota to S. and EC Wisconsin, eventually putting N Illinois in one or two MCS' late Thursday into Friday. I think we have a better chance here than we did last week, but I might as well prepare for a similar near miss in case it happens.

How does the Euro compare to the GFS and NAM? The NAM is much less bullish, but I'm not sure whether to discard it, since it does a poor job in the medium to long range.

Whether it's the NAM, GFS or Euro, they all have issues with convection, doesn't matter if it's summer or winter, it's a problem. They'll catch on the the major upper air players and give an idea of what's possible, but looking at QPF maps and following the blobs will set you up for disappointment and when you're looking at more than one possible round, the uncertainty is magnified because the mistakes get amplified downstream. Either way the best action always falls in a pretty narrow stripe so don't take it too seriously.

[Thundersnow12]

I'm going out of town weds so northern IL will once again get a good MCS or two out of this just like this past weekend.

[BeastFromTheEast]

I'm going out of town weds so northern IL will once again get a good MCS or two out of this just like this past weekend.

Thank you,

[A-L-E-K]

Nothing has changed from my previous thoughts, same general area as last weekend under the gun again, starting in eastern iowa and far southern wisconsin and then settling into northern illinois with the I88 area looking best for multiple rounds.

[wisconsinwx]

Haha, the 12z GFS puts the biggest swaths of rain in N. Wisconsin and N Illinois again, giving the areas in between some but not enough. As long as the corfidi vectors do their thing (steer tonight's MCS SE), we might get our welcome rain.

[Chicago Storm]

The ARW and NMM are showing the potential for several inches across E. Iowa/N. Illinois/S. Wisconsin.

[wisconsinwx]

The ARW and NMM are showing the potential for several inches across E. Iowa/N. Illinois/S. Wisconsin.

I saw those. Looks like the ARW in particular has an intense squall line roaring through Madison, Milwaukee, Rockford, and Chicago, among other cities, tomorrow evening.

Edit: it's the NMM, my bad.

[A-L-E-K]

The ARW and NMM are showing the potential for several inches across E. Iowa/N. Illinois/S. Wisconsin.

Pretty impressive totals there with more to come in later periods. Might be seeing flood watches before too long.

[Indystorm]

Sebenste on heavy rain chances

at least one or more

organized clusters of thunderstorms could roll through the area. With very high

moisture expected to be in place, any thunderstorms could produce rainfall rates

of up to 6" per hour over an area, dropping 2" or more of rain in a short period

of time. Confidence is increasing that flash flooding could become a concern for

some areas of northern Illinois tomorrow night into Thursday morning...and then

again later in the afternoon and evening if temperatures recover fast enough. I

have kept the flood risk at slight, but bumped it up to 25%. There might be a

somewhat higher risk of heavy rainfall at our Rockford and Lorado Taft campuses

closer to the front, but all areas are vulnerable. Current model rain estimates

along and north of I-88 are 1"-2.5" by the models, with locally heavier amounts,

of course, through Thursday night. A lesser but still significant threat of high

winds and quarter sized hail are possible. Additionally...barely enough wind

shear could occur for a very isolated tornado.

[wisconsinwx]

Sebenste on heavy rain chances

at least one or more

organized clusters of thunderstorms could roll through the area. With very high

moisture expected to be in place, any thunderstorms could produce rainfall rates

of up to 6" per hour over an area, dropping 2" or more of rain in a short period

of time. Confidence is increasing that flash flooding could become a concern for

some areas of northern Illinois tomorrow night into Thursday morning...and then

again later in the afternoon and evening if temperatures recover fast enough. I

have kept the flood risk at slight, but bumped it up to 25%. There might be a

somewhat higher risk of heavy rainfall at our Rockford and Lorado Taft campuses

closer to the front, but all areas are vulnerable. Current model rain estimates

along and north of I-88 are 1"-2.5" by the models, with locally heavier amounts,

of course, through Thursday night. A lesser but still significant threat of high

winds and quarter sized hail are possible. Additionally...barely enough wind

shear could occur for a very isolated tornado.

I think if a squall line the caliber of what the NMM is showing materializes, the severe weather threat will be more substantial than mentioned here.

[Hoosier]

Wettest months on record for Chicago:

17.10" Aug 1987

14.17" Sep 1961

13.63" Sep 2008

12.25" Aug 2001

12.06" Oct 1954

11.28" Aug 1885

10.58" Jun 1892

9.96" Jun 1993

9.70" Aug 2007

9.68" Aug 1977

9.56" Jul 1889

9.44" Sep 1977

9.04" Jul 2011

Definitely a shot to get into the top 5 depending on the exact evolution of these complexes.

[A-L-E-K]

I think if a squall line the caliber of what the NMM is showing materializes, the severe weather threat will be more substantial than mentioned here.

One of the main reasons i started the first heavy rain thread independent of the severe thread was the overall low probability of severe weather with these setups. Dynamics in general just won't be that great, sure it can be somewhat overcome by high/extremem instability and well developed cold pools, but i wouldn't anticipate widespread severe weather in this area. Training efficient rain producing convection will be the big story.

Wettest months on record for Chicago:

17.10" Aug 1987

14.17" Sep 1961

13.63" Sep 2008

12.25" Aug 2001

12.06" Oct 1954

11.28" Aug 1885

10.58" Jun 1892

9.96" Jun 1993

9.70" Aug 2007

9.68" Aug 1977

9.56" Jul 1889

9.44" Sep 1977

9.04" Jul 2011

Definitely a shot to get into the top 5 depending on the exact evolution of these complexes.

I'll say no ORD gets at least 1" by Friday afternoon and would say all the records but the top spot are at least in play.

[Thundersnow12]

Jesus

[A-L-E-K]

Jesus

yep, LOT mentions areas between i80m and i90 falling in the overlap zone, not to mention last week. Things could get real.

[Thundersnow12]

yep, LOT mentions areas between i80m and i90 falling in the overlap zone, not to mention last week. Things could get real.

ofcourse, and I will be gone again, ugh.

hopefully August brings more goods.

[wisconsinwx]

ofcourse, and I will be gone again, ugh.

hopefully August brings more goods.

It's real interesting how, at least around here, things have a way of evening out. It seems right after months with outrageous rain totals (like June 2008, with over 12 inches), the next couple months are real dry. That likely won't be the case, and for your sake, I hope it's not. I know how you feel.

[wisconsinwx]

One of the main reasons i started the first heavy rain thread independent of the severe thread was the overall low probability of severe weather with these setups. Dynamics in general just won't be that great, sure it can be somewhat overcome by high/extremem instability and well developed cold pools, but i wouldn't anticipate widespread severe weather in this area. Training efficient rain producing convection will be the big story.

I'll say no ORD gets at least 1" by Friday afternoon and would say all the records but the top spot are at least in play.

It won't have the potential of tonight's event, but SPC put up 30% probs in NE Iowa, and SW and parts of SC Wisconsin, so it is not as nonexistent as last week's heavy rainmakers were in terms of significant severe. If we don't get a whole lot of convection in the morning, there should be enough destabilization to put out an event of some sort. MKX even mentioned the potential for isolated tornadoes.

[wisconsinwx]

Throw out the 0z NAM right now. It's way too slow; it has the MCS currently exiting S. Dakota now still putting down rain in S Dakota around 12z.

[A-L-E-K]

ruh oh

[wisconsinwx]

Looks like some pretty decent rains on the way finally in the next few hours with more to come this afternoon and evening. Madison getting some much-needed rain as I speak.

[wisconsinwx]

My guess is I'll see close to an inch with this morning round. Hopefully it clears out in time to get some heating.

[BowMeHunter]

Got drizzle.. maybe can pick up a couple tenths with the little bit left to come through. This is not worth f'ing up a morning of fishing with pops.

[wisconsinwx]

Got drizzle.. maybe can pick up a couple tenths with the little bit left to come through. This is not worth f'ing up a morning of fishing with pops.

Don't be fooled, these storms are pretty efficient rain producers. Isolated spots back near Madison got around 3 inches per estimates.

[BowMeHunter]

Don't be fooled, these storms are pretty efficient rain producers. Isolated spots back near Madison got around 3 inches per estimates.

This is my back yard where rain turns to poop on me not madison lol. I'm just cranky because I wait all yr like its Christmas morning as a kid for this outing on Lake MI with our gang and now this nuisance rain I got so far screwed this trip up for a lot of the guys who can't reschedule for tomorrow AM.

prob got a couple tenths with the light to mod stuff that just rolled through. few blobs of decent rain rain to the SW but who knows what they do and I don't except to get lucky with them.. prob end up with a third of an inch if that and pretty much what expected with higher amounts west and north.. See what this evening and tonight brings

[A-L-E-K]

Don't be fooled, these storms are pretty efficient rain producers. Isolated spots back near Madison got around 3 inches per estimates.

meh, madison got about .5" per radar estimates with a small stripe of 1.5-2.5 well west of there. Everything seems to be playing out as expected with far western Wisconsin getting the brunt of round 1. I'd looked for additional scattered action to keep firing north of the wf into WI during the day. The main show will be the linear MCS that will probably getting going just north of the border this evening and slide ese with the cold front overnight. Right now i'd favor 1 county row north or south of the border for the main show overnight.

[wisconsinwx]

This is my back yard where rain turns to poop on me not madison lol. I'm just cranky because I wait all yr like its Christmas morning as a kid for this outing on Lake MI with our gang and now this nuisance rain I got so far screwed this trip up for a lot of the guys who can't reschedule for tomorrow AM.

prob got a couple tenths with the light to mod stuff that just rolled through. few blobs of decent rain rain to the SW but who knows what they do and I don't except to get lucky with them.. prob end up with a third of an inch if that and pretty much what expected with higher amounts west and north.. See what this evening and tonight brings

Yeah, it's a shame the airport has to be located near there, but what can you do? It looks like those heavier showers and storms will move through the southern part of the county. If it was severe convection I would agree they would weaken as they head toward you, but the atmosphere is moist, especially with increasing precipitable water values, that I think you'll be good to go for some more rain.