Sept-Oct heavy rain and Flooding threat

[janetjanet998]

The potential exists for very heavy rain and eventually river flooding over MN, IA, WI and N IL maybe ENE into MI

The pattern seems stuck with a strong high off the East coast with tropical moisture flowing north into the midwest...

Due to recent heavy rains , soil moisture is high and some smaller rivers are in flood in WI.(Kickapoo had record flooding a few days ago)..Northern MO area has been in a drought but heavy rains this morning are weakening the "drought shield" for that area

A ring of fire type pattern is setting up..WPC 7 day rainfall amounts are 4-5 inches from eastern NE into WI(of course isolated higher amounts)

Medium range models suggest this pattern may continue for at least the next 10 days....with mesoscale outflows likely playing a role where the daily heavy rain train sets up

Of course any tropical systems moving around the ridge later on may also add to all of this too

In Summary: major daily flash flood events likely....developing into main stream river flooding events

 

 

 

 

 

 

 

 

 

 

[janetjanet998]

no change really from the new WPC maps...4-5 inches from NE into WI next 7 days...

 

the 18z NAM products are rather concerning for eastern IA into N IL....a little south trend

 

models didn't handle the MO convection well today and that held up the warm front some from moving north ....

 

 

[Hoosier]

Really the question is what kind of totals will there be on a smaller scale. Definitely wouldn't be surprised to see somebody get double digits again.

[hawkeye_wx]

I'm actually getting a bit worried about the first round.  Tonight was going to be our first big night, but the latest 3k nam and hrrr show nothing here.  They have convection blowing up over sw Iowa, which would then move east and southeast, leaving us dry.  Heck, the 3k nam also has nothing Saturday night.

[janetjanet998]

2 hours ago, hawkeye_wx said:

I'm actually getting a bit worried about the first round.  Tonight was going to be our first big night, but the latest 3k nam and hrrr show nothing here.  They have convection blowing up over sw Iowa, which would then move east and southeast, leaving us dry.  Heck, the 3k nam also has nothing Saturday night.

well, as you know,  short range models often perform poorly in these set ups due to unpredictable meso features....for example,  there seems to be a disturbance over NE IL this evening that the models missed or were too weak with...... 1-2 inches of "bonus" rains down(could prime the ground even more if later rains also hit there) and a t-storm warning thrown it for good measure 

 

if a few hours the LLJ should show its hand and give clues for the overnight train location

[CheeselandSkies]

This could be disastrous. River flooding on the Kickapoo and Baraboo Rivers in WI is already rivaling June 2008 levels in some areas. Many of the same communities have been inundated. Only thing missing is a big/destructive breach like happened at Lake Delton.

[janetjanet998]

MKE update pretty much sums it up

 

REA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
646 PM CDT FRI AUG 31 2018  
   
UPDATE  
  
STILL SOME UNCERTAINTY WITH HOW THINGS WILL EVOLVE OVERNIGHT  
TONIGHT, BUT THERE IS GROWING CONSENSUS THAT THE AREA SHOULD BE  
MOSTLY DRY THROUGH MIDNIGHT. AFTER MIDNIGHT, THUNDERSTORMS WILL  
BEGIN TO BLOSSOM AS THE LOW LEVEL JET IS ABLE TO TAP INTO A SOLID  
1500-2000 J/KG OF ELEVATED CAPE. WITH SUFFICIENT BULK SHEAR, A FEW  
STRONGER STORMS WILL BE POSSIBLE. GIVEN THE ELEVATED NATURE TO THE  
THUNDERSTORMS, THE SEVERE WEATHER THREAT SHOULD BE LIMITED TO   
LARGE HAIL.  
  
OF GREATER CONCERN IS THE POTENTIAL FOR HEAVY RAIN. PWATS WILL  
INCREASE TO 2"+ OVERNIGHT, WITH SLOW STORM MOTIONS. THERE MAY ALSO  
BE SOME POTENTIAL FOR BACKBUILDING, AS CORFIDI VECTORS FALL TO  
LESS THAN 10 KNOTS BY THE PRE-DAWN HOURS. ALL OF THIS SUGGESTS  
THAT SOME LOCATIONS WILL LIKELY SEE PERIODS OF VERY HEAVY RAIN,  
BUT WITH LITTLE IN THE WAY OF SURFACE FEATURES TO ORGANIZE  
CONVECTION, IT'S TOUGH TO PINPOINT ANY SPECIFIC AREA THAT HAS THE  
HIGHEST POTENTIAL AT THIS TIME. THE FLASH FLOOD WATCH IS WELL-  
PLACED WITH THOSE AREAS THAT HAVE THE LEAST TOLERANCE FOR  
ADDITIONAL RAINFALL, AND THESE AREAS WILL CERTAINLY BE OF   
GREATEST CONCERN FOR IMPACTS SHOULD THEY SEE THE RAIN OVERNIGHT

[IWXwx]

25 minutes ago, janetjanet998 said:

well, as you know,  short range models often perform poorly in these set ups due to unpredictable meso features....for example,  there seems to be a disturbance over NE IL this evening that the models missed or were too weak with...... 1-2 inches of "bonus" rains down(could prime the ground even more if later rains also hit there) and a t-storm warning thrown it for good measure 

 

if a few hours the LLJ should show its hand and give clues for the overnight train location

You're right about the short range models and the same thing happened in Southern IN this afternoon where a cluster of storms blew up and dumped heavy rains over a few counties this afternoon even though nothing was modeled. It's setup where if a butterfly flaps its wings.....

[Geoboy645]

3 hours ago, janetjanet998 said:

MKE update pretty much sums it up

 

REA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI  
646 PM CDT FRI AUG 31 2018  
   
UPDATE  
  
STILL SOME UNCERTAINTY WITH HOW THINGS WILL EVOLVE OVERNIGHT  
TONIGHT, BUT THERE IS GROWING CONSENSUS THAT THE AREA SHOULD BE  
MOSTLY DRY THROUGH MIDNIGHT. AFTER MIDNIGHT, THUNDERSTORMS WILL  
BEGIN TO BLOSSOM AS THE LOW LEVEL JET IS ABLE TO TAP INTO A SOLID  
1500-2000 J/KG OF ELEVATED CAPE. WITH SUFFICIENT BULK SHEAR, A FEW  
STRONGER STORMS WILL BE POSSIBLE. GIVEN THE ELEVATED NATURE TO THE  
THUNDERSTORMS, THE SEVERE WEATHER THREAT SHOULD BE LIMITED TO   
LARGE HAIL.  
  
OF GREATER CONCERN IS THE POTENTIAL FOR HEAVY RAIN. PWATS WILL  
INCREASE TO 2"+ OVERNIGHT, WITH SLOW STORM MOTIONS. THERE MAY ALSO  
BE SOME POTENTIAL FOR BACKBUILDING, AS CORFIDI VECTORS FALL TO  
LESS THAN 10 KNOTS BY THE PRE-DAWN HOURS. ALL OF THIS SUGGESTS  
THAT SOME LOCATIONS WILL LIKELY SEE PERIODS OF VERY HEAVY RAIN,  
BUT WITH LITTLE IN THE WAY OF SURFACE FEATURES TO ORGANIZE  
CONVECTION, IT'S TOUGH TO PINPOINT ANY SPECIFIC AREA THAT HAS THE  
HIGHEST POTENTIAL AT THIS TIME. THE FLASH FLOOD WATCH IS WELL-  
PLACED WITH THOSE AREAS THAT HAVE THE LEAST TOLERANCE FOR  
ADDITIONAL RAINFALL, AND THESE AREAS WILL CERTAINLY BE OF   
GREATEST CONCERN FOR IMPACTS SHOULD THEY SEE THE RAIN OVERNIGHT

I really hope I don't wake up tomorrow to 2008 v2 with the Crawfish.

[janetjanet998]

 

 

Large MCS over IA into NW IL and SW WI. 3-4 inches down in areas.'...isolated 6-7 inches ......with widespread 1+ inch amounts

Waterloo IA 3.02 inches since midnight

The MCS would start to weaken here this morning and become more progressive as it moves east into CHI metro

However this will prime the ground for whatever develops this afternoon and tonight for round 2...which the exact location won't be known until later 

WPC has still has 5+ inches the next 7 days from NE into WI..with a bullseye of 7 inches over SW IA

IMO extreme rainfall amounts are possible the next week if the train tracks don't fluctuate north/south much each day

 

 

 

 

[hawkeye_wx]

14 hours ago, hawkeye_wx said:

I'm actually getting a bit worried about the first round.  Tonight was going to be our first big night, but the latest 3k nam and hrrr show nothing here.  They have convection blowing up over sw Iowa, which would then move east and southeast, leaving us dry.  Heck, the 3k nam also has nothing Saturday night.

Well, we certainly didn't end up dry as a big MCS plowed across Iowa.  However, I did kinda get screwed and ended up in a dry pocket when the backbuilding back edge stalled to the west and stuck Cedar Rapids in lighter rain.  I picked up 0.87" once the storms morphed into a steady rain shield.  Even now, the back edge is trying to re-energize and miss north.

[janetjanet998]

12 NAM favors N IL  back into IA with a 4-7 inch thin stripe before the train moves North and West monday as the ridge builds back a little more NW on the East Coast,,

it seems to be a hair too far north with this mornings MCS though...

 

it seems the OMA NE area gets overlapped with the tracks (west-east moving then south-north)  and the NAM cracks out 7-10  inches around there

[janetjanet998]

after the previous training days.....both the 12z CMC and GFS develop a tropical system in the gulf and move it up this way...GFS further east and faster 

CMC/GEM solution seems to have the flow around it overriding a front with epic precipitation amounts

 

 

[Hoosier]

1 hour ago, janetjanet998 said:

after the previous training days.....both the 12z CMC and GFS develop a tropical system in the gulf and move it up this way...GFS further east and faster 

CMC/GEM solution seems to have the flow around it overriding a front with epic precipitation amounts

 

 

12z Euro has a landfalling system in southeast Louisiana in just under 96 hours.  

We should know in the next day or two if there's going to be an organized system, though it may not actually matter that much... can still get the moisture without significant cyclone development.

[Hoosier]

Tropical system looks like it gets buried in Texas on the Euro.  Not really seeing anything to steer it this way on this run.  

[Indystorm]

Flash flood watches out from western MI west through northern IL and IA to eastern Nebraska.  Storms starting to form that east/west training line.

[janetjanet998]

Round 2 starting ... WPC still has that same stripe of 5 to 7 inches over the next 7 days 

 

looks like they keep the tropical low over Texas  via the 6/7 day QPF 

[Chicago Storm]

A few storms that develop across the area this evening had supercell characteristics and some rotation, one of which passed through here.

Since then a nice train has set up, though slowly shifting north. Looks like some heavy rain/flood issues for the northern tier tonight.

[Hoosier]

26 minutes ago, Chicago Storm said:

A few storms that develop across the area this evening had supercell characteristics and some rotation, one of which passed through here.

Since then a nice train has set up, though slowly shifting north. Looks like some heavy rain/flood issues for the northern tier tonight.

I was out between Valpo and Wheatfield tonight and saw frequent lightning to the north.  Was a little surprised to see how far away the storms were when I checked radar.

[janetjanet998]

NO change to WPC precip maps maps.MOD risk for excessive rainfall today, Slight tomorrow , and then moderate again tuesday

NWS Weather Prediction Center College Park MD
439 AM EDT Sun Sep 02 2018
 
Day 1
Valid 12Z Sun Sep 02 2018 - 12Z Mon Sep 03 2018 

...MODERATE RISK OF EXCESSIVE RAINFALL OVER THE MID MS VALLEY... 

...Central Plains into the Mid MS Valley and Great Lakes...
Another active convective day from portions of the Central Plains 
into the Great Lakes. Overall a similar setup to what we have been 
seeing the past few days with the region in between the upper 
level troughing over the west and ridging over the east. The 
synoptic setup is probably not quite as good over IA/WI/IL as it 
has been...with the upper jet displaced a bit further north and 
weaker 850mb moisture transport forecast. But will continue to 
have a boundary in place, weak to moderate low level flow into the 
boundary, and another shortwave pushing northeast across the area. 
PWs will also be equal or even a bit higher compared to yesterday. 
Thus appears likely that additional convection will occur across 
IA into southern WI and northern IL this afternoon and overnight. 
Like the synoptic situation, the high res model signal is not 
quite as robust over the area today either...but still suggesting 
an additional 1-3"...and still the potential for localized 3-5" 
totals given the persistent (albeit weaker) moisture transport 
supportive of some training/backbuilding and higher PWs. Given the 
heavy antecedent rainfall over central and southern IA, this 
additional rainfall likely poses an elevated flash flood threat. 
For this reason have opted to upgrade to a Moderate Risk for much 
of southern and central IA, with additional flash flooding likely 
today. Some potential this may need to be expanded into portions 
of northern IL and southern WI as well...although at this time the 
signal for 3"+ additional amounts is lower here, and thus will 
maintain a Slight for now.

The heaviest rainfall magnitudes over the day 1 period may 
actually end up falling further south across central KS into far 
southeast NE. 850mb moisture transport is more impressive across 
this corridor...and the persistent and stationary nature of this 
moisture transport axis is very favorable for backbuilding and 
training convection. Thus would appear like a corridor of longer 
duration heavy rains is possible, with both the 0z HREF and HRRR 
indicating pockets of 5"+ totals. Current indications are that 
this activity should end up mainly south of where the heaviest 
antecedent rainfall has been. For this reason will keep the risk 
level at Slight across KS and southeast NE. But will need to 
monitor through the day...as the setup does have the potential to 
warrant an upgrade even if the rainfall falls over drier grounds. 
And if there were to be a shift north in the axis into areas that 
were recently hit hard, then additional flash flooding would 
certainly become likely and warrant an upgrade. Thus will keep an 
eye on trends and reevaluate as the day progresses. 

 

[janetjanet998]

Long term AFD from DVN mentions tropical  system

 

ONG TERM  
(MONDAY THROUGH NEXT SATURDAY)  
ISSUED AT 330 AM CDT SUN SEP 2 2018  
  
THE LATEST SUITE OF MEDIUM RANGE MODELS KEEP THE MID SUMMER-LIKE  
RING OF FIRE GOING FOR MUCH OF THE UPCOMING WEEK IN OR NEAR THE  
LOCAL AREA OF CONCERN. STILL SOME HOPE THAT MID LEVEL RIDGE   
RETROGRADE OR AMPLIFICATION SHUNTS THE MAIN HEAVY RAIN AXIS JUST   
TO THE WEST AND NORTH OF THE LOCAL AREA, BUT PORTIONS OF THE CWA   
WILL STILL BE SUSCEPTIBLE TO AT LEAST GETTING CLIPPED BY STORMS   
AND MORE BOUTS OF HEAVY RAIN, ESPECIALLY THE NORTHWEST AND   
NORTHERN THIRD OF THE FCST AREA THROUGH WED. THERE COULD BE ALMOST  
THE DAILY NEED FOR A FLOOD WATCH FOR PORTIONS OF THE AREA FOR   
MUCH OF THE UPCOMING WEEK. COMPOUNDED ROUNDS OF HEAVY RAIN IN OR   
NEAR THE AREA WILL IMPACT RIVER BASINS WITH ROUTED FLOW, OR   
LOCALIZED RAIN PRODUCING INCREASED RIVER FLOODING AS THE WEEK   
PROGRESSES. WILL ALSO HAVE TO WATCH FOR THE TROUBLING SIGN OF   
REMNANTS OF A TROPICAL SYSTEM GETTING DRAWN UP TOWARD THE AREA BY  
NEXT WEEKEND OR THE WEEK AFTER, WHICH COULD REALLY COMPOUND   
FLOODING PROBLEMS IN AN AREA HIT BY OCCASIONAL BOUTS AND SWATHS   
OF HEAVY RAIN FOR OVER A WEEK. THE 00Z GFS BREAKS THE FLOODING   
PATTERN BY SEPT 10TH OR 11TH WITH A BIG COOL DUMP/LONG WAVE TROF   
OUT OF CANADA.  
  

[hawkeye_wx]

The first two nights of storms and heavy rain have really dumped on some areas, but Cedar Rapids has been stuck in the dry hole, just downstream of the heavy storms, both nights.  I was only able to get 0.12" last night.

[janetjanet998]

45 minutes ago, hawkeye_wx said:

The first two nights of storms and heavy rain have really dumped on some areas, but Cedar Rapids has been stuck in the dry hole, just downstream of the heavy storms, both nights.  I was only able to get 0.12" last night.

12z NAM and WPC discussion: well day/night 3 of the train may be missing a few box cars over IA/IL ..still heavy rains though in IA/IL/WI ..seems KS/NE get smoked ..

tomorrow looks like the train is back around you

tuesday it may shift north and west

I should note there is a tropical disturbance near LA and the NAM takes some of this moisture and seems to increase PW values even more coming up into the midwest ...but it does push the train well SE by 84 hours as high pressure builds into MN

 

[cyclone77]

Picked up 0.67" from yesterday morning's storm complex.  The storms last eve stayed just to the north but put on a hell of a light show.  It was enough to even knock the power out for a short time as a barrage of CGs skirted a bit north of town.  

Think the best shot at heavy rain will be north and west of the QC tonight, but it's close enough we'll have to keep an eye on it.  

[janetjanet998]

Both the 12z GFS and CMC have that tropical system up this way with the GFS more east...

 

at least it takes the high PW moisture with it as it moves east next weekend

[Chicago Storm]

12 hours ago, Hoosier said:

I was out between Valpo and Wheatfield tonight and saw frequent lightning to the north.  Was a little surprised to see how far away the storms were when I checked radar.

Yea, I heard that from others that it was visible from a far distance.

Lightning was prolific all night here. Not a ton of CG's though.

[janetjanet998]

12z ECWMF also has a shreared out version of that tropical system near STL at 192 hours..major difference between it and GFS at days 8-9 

 

 

 

DVN HYDROLOGY  
  
ISSUED AT 103 PM CDT SUN SEP 2 2018  
  
TORRENTIAL RAINS FELL ONCE AGAIN OVER THE AREA LAST NIGHT. THESE  
RAINS FELL ON THE UPPER REACHES OF TRIBUTARY RIVERS THAT FLOW INTO  
OUR CWA, MOST PROLIFICALLY ON THE ENGLISH, IOWA, WAPSIPINICON AND  
ROCK RIVERS. RAINFALL OF 1 TO 2 INCHES WAS COMMON, WITH SOME 3 TO  
4 INCH REPORTS IN IOWA COUNTY, AND JO DAVIESS/STEPHENSON COUNTIES.  
THESE RAINS, COMBINED WITH ONGOING HIGH WATER, AND FORECAST  
RAINFALL AHEAD ARE RESULTING IN HIGHER THAN NORMAL CONFIDENCE IN  
RIVERS REACHING FLOOD STAGE,MODERATE FLOOD STAGE AND EVEN MAJOR IN  
ONE CASE. FOR THAT REASON, WE HAVE BYPASSED USING THE WATCH WITH  
RESPECT TO A FEW POINTS THAT ARE AROUND 3 DAYS OUT FROM REACHING  
FLOOD LEVEL. THIS WET PATTERN IS HIGH ENOUGH CONFIDENCE THAT  
FORECASTS ARE MORE LIKELY TO INCREASE THAN FALL SHORT ONCE ALL THE  
WEEK'S RAINS FALL.   
  
THE ENGLISH RIVER AT KALONA GOT HIT WITH FLASH FLOODING RAINS  
AGAIN LAST NIGHT, THEREFORE, HITTING 18 FEET OF MAJOR SEEMS LIKELY  
AND WE HAVE ISSUED A WARNING REACHING MAJOR. MARENGO IS IN A  
SIMILAR POSITION ON THE IOWA RIVER, BUT IS EXPECTED TO REMAIN  
MODERATE TODAY. IN ADDITION, MODERATE FLOODING IS EXPECTED ON THE  
IOWA RIVER AT OAKVILLE AND WAPELLO. ON THE SKUNK, SIGOURNEY SHOULD  
ALSO NOW REACH MODERATE, POSSIBLY NEAR MAJOR. ONCE AGAIN, FUTURE  
RAINS MAY FORCE HIGHER LEVELS.   
  
THE WAPSI AT DEWITT 4S SAW MODERATE STAGE RISE YESTERDAY, AND IS  
FALLING, BUT ROUTED WATER WILL ONCE AGAIN CAUSE MODERATE FLOODING  
IN THE NEXT FEW DAYS.   
  
THE MISSISSIPPI IS RISING, AND WITH SO MANY TRIBS SHOOTING UP, IS  
LIKELY TO BE ADJUSTED FARTHER. FOR NOW, THE CONFIDENCE ON MINOR  
FLOOD IS HIGH ENOUGH TO ISSUE WARNINGS FOR NEW BOSTON ON  
DOWNSTREAM, EXCEPT FOR KEOKUK.  
  

[KM_F]

New Hampton, Ia: 8/27 1.21"; 8/28 .62"; 8/29 3.5"; 9/1 1.47"; 9/2 1.63" so far. The hail from our yard on 8/28. An awful lot of rain in the last few days.

Sent from my Pixel 2 XL using Tapatalk

[hawkeye_wx]

The euro continues to be extremely bullish with the rain through the entire week.  While the GFS, and even the Canadian, have been hinting the rain may be swept away to the east and south as early as Wednesday night, the euro keeps an upper disturbance parked over NE/KS/IA, which pumps high moisture into Iowa like a conveyor.  Today's 12z run has widespread 5-12 inches of rain across the state through Saturday.

[janetjanet998]

19 minutes ago, hawkeye_wx said:

The euro continues to be extremely bullish with the rain through the entire week.  While the GFS, and even the Canadian, have been hinting the rain may be swept away to the east and south as early as Wednesday night, the euro keeps an upper disturbance parked over NE/KS/IA, which pumps high moisture into Iowa like a conveyor.  Today's 12z run has widespread 5-12 inches of rain across the state through Saturday.

seems it also keeps a southerly flow  in the plains days 8-9 while the GFS Builds in a high...in not sure what the moisture and precip are though,..I assume it is shunted east and has to rebuild 

This also seems to plow  Florance into the east coast ...while the GFS is well east with the stronger trough east