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June 20-21 and June 24-27 Heavy Rain/Severe Threats


Hoosier

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The 12km NAM is very much different than the 4km. The 4km shows a significant MCS that transverses northern Illinois/Indiana and makes it all the way to western Ohio before dissipating. 

 

The HRRR shows a mess of junk convection ongoing across much of Iowa by 11 a.m. CDT. #2015ing.

 

Edit: Note that the NAM has really struggled with convection, especially convective initiation in the short-term. It's not doing so well in that respect so far tonight either.

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Despite everyone dogging it yesterday, the 6/22/15 12z & 18z run of the 4 KM NAM actually handled yesterday evening and night's convection very well and was the only model to latch onto the idea of a string of supercells from Northern Missouri and Iowa up to Michigan despite the morning convection.

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The question is, are we going to be seeing a MCS or anything in the morning? I am in Chicago.. That could hinder things for the day like it did yesterday. 

There's gonna be one ongoing to Chicago's southwest at 12z... and almost every NWS office in the current enhanced risk talked about it. Yet, most of them remain certain about severe potential. DMX seemed to be the most certain. 

 

If someone already posted DMX or ILX's afternoon AFD, tell me and I'll delete it. 

 

.LONG TERM /WEDNESDAY THROUGH TUESDAY/...

ISSUED AT 343 PM CDT TUE JUN 23 2015

SEVERE WEATHER OUTBREAK AND HEAVY RAIN POTENTIAL ON WEDNESDAY

INTO WEDNESDAY NIGHT WAS THE MAIN CONCERN OVER THE EXTENDED

PERIOD. LEANED TOWARD A NAM/ECMWF BLEND FOR POP/WX TRENDS

WEDNESDAY INTO WEDNESDAY NIGHT AS GFS SEEMS TOO FAR NORTH WITH

THE WARM FRONT AND THUS CONVECTION.

WEDNESDAY INTO WEDNESDAY NIGHT...ONGOING MCS TONIGHT IS

ANTICIPATED TO PERSIST THROUGH THE MORNING HOURS OVER FAR

SOUTHERN IOWA AND LOOKS TO STAY SOUTH OF HIGHWAY 34 TO THE

MISSOURI BORDER. QUESTIONABLE HOW FAR NORTH THE WARM FRONT WILL

SURGE ASSOCIATED WITH THE SURFACE LOW EJECTING OUT OF THE CENTRAL

ROCKIES TOMORROW. THIS IS CERTAINLY DEPENDENT ON THE MCS LOCATION

OVERNIGHT TONIGHT...BUT THE NAM/ECMWF AND EVEN THE GFS HAVE A

DECENT HANDLE ON CURRENT CONVECTIVE TRENDS BUT DIFFER IN SOLUTIONS

BY WEDNESDAY MORNING. THE WARM FRONT SHOULD SURGE NORTH TO

NORTHEAST THROUGH THE DAY WEDNESDAY AND LOOKS TO SET UP BETWEEN

INTERSTATE 80 TO HIGHWAY 20 AND BE SLIGHTLY ORIENTED NORTHWEST TO

SOUTHEAST BY THE LATE AFTERNOON. STRONG IMPULSE PUNCHES INTO

WESTERN IOWA BY THE AFTERNOON AND TRANSITIONS EAST THROUGH THE

STATE INTO THE EVENING HOURS WEDNESDAY. STRONG WAA...MOISTURE

TRANSPORT AND THETA-E ADVECTION INTO THE STATE BEHIND THE WARM

FRONT ALLOWING FOR THE ATMOSPHERE TO QUICKLY DESTABILIZE. THE

SURFACE BASED CAPE INCREASES TO AT LEAST 2500 J/KG BUT POSSIBLY

RISING OVER 4500 J/KG BY THE LATE AFTERNOON ALONG THE MO/IA

BORDER. WEAK CAP IN PLACE...BUT AFOREMENTIONED UPPER LEVEL VORT

MAX WILL BE STRONG ENOUGH TO INITIATE STORMS. DEEP LAYER SHEAR

RANGES FROM 45 TO 55 KNOTS AND 0-1 KM SHEAR RANGES FROM 20-25

KNOTS WITH GOOD VEERING THROUGH THE LOWER LEVELS LEADING TO A

DECENT TORNADIC POTENTIAL...ESPECIALLY IF STORMS TIE INTO THE

SURFACE BOUNDARY TO ENHANCE ANY LOW LEVEL VORTICITY. LARGE HAIL

AND WIND ARE ALSO HIGHLY LIKELY WITH THESE STORMS. HENCE...HIGH

CONFIDENCE IN SEVERE WEATHER POTENTIAL ACROSS A GOOD PORTION OF

THE FORECAST AREA TOMORROW AFTERNOON THROUGH THE EVENING.

 

ILX

.LONG TERM...(WEDNESDAY THROUGH TUESDAY)

ISSUED AT 305 PM CDT TUE JUN 23 2015

THE WARM FRONT WILL SLOWLY LIFT NORTHWARD TOMORROW...BUT EXACTLY HOW

FAR NORTH IT WILL MAKE IT REMAINS IN QUESTION...ESPECIALLY IF THERE

IS A WELL DEVELOPED MCS TO OUR WEST LATE TONIGHT WHICH SHOULD WEAKEN

AS IT PUSHES INTO OUR AREA DURING THE MORNING ON WEDNESDAY. SEVERAL

HI-RES MODELS SUGGEST THE REMNANTS OF THE CONVECTION WILL SLOWLY PUSH

ACROSS MAINLY OUR WEST AND SOUTHWEST TOMORROW BEFORE DECREASING IN

COVERAGE BY AFTERNOON. THIS MAY HOLD BACK THE NORTHWARD PUSH OF THE

WARM FRONT DURING THE DAY WITH THE REAL STRONG PUSH NORTH TOMORROW

NIGHT AS A COMBINATION OF STRONG LOW LEVEL THETA-E ADVECTION AND

MOISTURE TRANSPORT OCCURS AHEAD OF THE APPROACHING SHORTWAVE. THIS

COMBINED WITH PRECIPITABLE WATER VALUES OF AROUND 2 INCHES AND MOST

UNSTABLE CAPE VALUES OF 2500-3000 JOULES/KG WILL LEAD TO A STRONG TO

SEVERE FORWARD PROPAGATING MCS TO OUR WEST/NORTHWEST WHICH WILL

SHIFT EAST-SOUTHEAST INTO OUR AREA LATER TOMORROW EVENING/OVERNIGHT.

NAM-WRF BUFKIT SOUNDINGS FOR TOMORROW EVENING EXHIBIT 30-40 KTS

INFLOW (850 MB LOW LEVEL JET) AND WARM CLOUD DEPTHS IN EXCESS OF

12,500 FT WHICH WILL BE VERY EFFICIENT RAIN MAKERS. AREAS ALONG AND

NORTH OF A CANTON TO BLOOMINGTON LINE WILL BE INCLUDED IN ON A

FLASH FLOOD WATCH FOR WEDNESDAY NIGHT THRU THURSDAY MORNING FOR

THE POTENTIAL FOR HEAVY TO EXCESSIVE RAINFALL AMOUNTS OF 1.5 TO

2.5 INCHES WITH AREAS POTENTIALLY SEEING OVER 3 INCHES WITH THIS

TYPE OF SETUP.

 

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Despite everyone dogging it yesterday, the 6/22/15 12z & 18z run of the 4 KM NAM actually handled yesterday evening and night's convection very well and was the only model to latch onto the idea of a string of supercells from Northern Missouri and Iowa up to Michigan despite the morning convection.

They did...even the 4k 12z 21JUNE had the main show in northern IL being that lone sup that rolled through down to kankakee...truthfully i mostly only watched northern il action though on the model runs

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Basing off of the solution by the 00Z 12KM NAM it looks like we could be looking at another derecho... Across N IA/ S WI/ N IL and into E/W MI... NAM develops a pretty strong MCV it appears, convective enhanced low... with westerly/sw'ly H85 flow at ~50-60kts, and 45-55kts at H925 feeding into this starting around 06Z and increasing through the morning. Instability looks questionable though... But doubt that that will matter much with STRONG moisture loading taking place, to help bring that strong LLJ down to the surface. Also looks like the southern end of the MCS/ bow/ whatever it'll be could have some decent spin-up tornado potential as well, especially if it is semi-discrete/ transient supercell-type structures on the tail end, as it will be feeding off a reservoir of at least moderately strong instability juxtaposed to extreme 0-3/0-1KM SRH of 350-550m2/s2. Thoughts? 

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Basing off of the solution by the 00Z 12KM NAM it looks like we could be looking at another derecho... Across N IA/ S WI/ N IL and into E/W MI... NAM develops a pretty strong MCV it appears, convective enhanced low... with westerly/sw'ly H85 flow at ~50-60kts, and 45-55kts at H925 feeding into this starting around 06Z and increasing through the morning. Instability looks questionable though... But doubt that that will matter much with STRONG moisture loading taking place, to help bring that strong LLJ down to the surface. Also looks like the southern end of the MCS/ bow/ whatever it'll be could have some decent spin-up tornado potential as well, especially if it is semi-discrete/ transient supercell-type structures on the tail end, as it will be feeding off a reservoir of at least moderately strong instability juxtaposed to extreme 0-3/0-1KM SRH of 350-550m2/s2. Thoughts? 

Maybe another derecho... but not so much in the places you outlined... specifically north Indiana and Michigan. I see you're seeing the high reflectivity, but for the most part, I think the MCS is north of the warm front... where there's essentially no instability.

 

post-13588-0-12566500-1435116702_thumb.g

post-13588-0-81870600-1435116706_thumb.g

Yes, I realize the warm fronts I drew don't match up. :P

 

I think the MCS is being caused by the WAA... and will get pushed away from the instability. I'm thinking a possible derecho for Iowa/Illinois/west and central Indiana

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Maybe another derecho... but not so much in the places you outlined... specifically north Indiana and Michigan. I see you're seeing the high reflectivity, but for the most part, I think the MCS is north of the warm front... where there's essentially no instability.

 

attachicon.gifZjrn9o9.gif

attachicon.gifQcAo9Ba.gif

Yes, I realize the warm fronts I drew don't match up. :P

 

I think the MCS is being caused by the WAA... and will get pushed away from the instability. I'm thinking a possible derecho for Iowa/Illinois/west and central Indiana

Well, I mentioned that instability was likely an issue...But with the very impressive amount of flow at H7 (70-80kts),H85(50-60kts), and H925 (45-55kts) it just seems like given the amount of moisture loading at least some of those winds could get translated down to the surface... But guess I could be/probably will be wrong... we will see. Might not even matter since the NAM solution is a quite bit different  (further north) than some other 00Z guidance.

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I'm still pretty hesitant about surface based convection making it as far north as some of these models are showing.  HRRR and even the 4km keep backbuilding/festering zombie vection going in Iowa for much of the day tomorrow.  Unlike yesterday, we don't have a potent surface low and associated upper level system to really help draw everything further north.  I'm guessing the effective warm front will hang out in southern Iowa most of the day tomorrow, and really won't get much of a chance to advance north before the main show kicks off late afternoon/early evening.  I think the best shot for meaningful severe will stay south of a Des Moines to Pontiac IL line.  My 2 cents anyway.

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Well, I mentioned that instability was likely an issue...But with the very impressive amount of flow at H7 (70-80kts),H85(50-60kts), and H925 (45-55kts) it just seems like given the amount of moisture loading at least some of those winds could get translated down to the surface... But guess I could be/probably will be wrong... we will see. Might not even matter since the NAM solution is a quite bit different  (further north) than some other 00Z guidance.

True about the winds translating down... especially if there's convection. But I don't think it would be enough for severe-caliber winds. I just think back to cool season HSLC squalls. Even with the most extreme shear (60+ knots at 925mb, etc), you need a few hundred joules/kg of CAPE to get severe winds. We had 4 HSLC squalls between October 2013 and February 2014... I don't think we ever got more than 200 j/kg in any case.

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As far what I expect though for the 06Z SWODY1... Probably a near continuation of the D2 1730Z due to uncertainties of how the possible morning MCS/ elevated convection will evolve. BUT due to the decent model agreement about a SVR MCS moving across the ENH risk area as well as the environment in place could see a possible upgrade to MDT (probably for the 1630Z update if concerns diminish about morning/early afternoon convection) across parts of E IA/W IL for damaging winds... Otherwise 10% hatched TOR for possible tornado threat early in the evening with any discrete supercell along the Warm Front IF there is not too much concern over morning convection, with the possibility of a strong tornado or two due to the impressive LLVL SHR and 0-3KM SRH ... As well as 30% hatched for large hail, with the possibility of an upgrade to 45% should concerns regarding convective evolution diminish, and the threat of more discrete convection prior to upscale growth becomes evident. 

 

But like has been mentioned, all this is dependent on the convective progression during the morning and early afternoon. In any event, even with persistent convection into the afternoon, the threat would likely just shift further south which could potentially compromise the potential for a higher-end threat due to it becoming increasingly displaced from mid-level support, but we will see in about 12 hours or so.

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I've been a lurker here for awhile (I own the WilmingtonWx site) and I figured this would make for a suitable first post. Looking at the 00Z CIPS Analogs, the 9th best match is the June 13th, 2013 Ohio Valley Derecho series. That was a wind driven High risk day from the SPC and although the chances that event is matched are slim, the CAMS are showing a very similar - albeit less intense for now - scenario playing out. First an MCS rides from Chicagoland south into Ohio laying out an OFB that triggers a squall line that sweeps further south. Interested to see how the Wednesday MCS affects Thursday's here at CMH.

 

http://www.eas.slu.edu/CIPS/ANALOG/stats.php?reg=EC&model=NAM212&fhr=F048&rundt=2015062400

 

nam4km_ref_ncus_11.pngnam4km_ref_neus_17.png

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Still non river flooding problems ongoing in places hit hard last night...

FLOOD STATEMENT

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

1025 PM CDT TUE JUN 23 2015

LA SALLE IL-WILL IL-KANKAKEE IL-LEE IL-KENDALL IL-GRUNDY IL-

NEWTON IN-JASPER IN-

1025 PM CDT TUE JUN 23 2015

...A FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 AM CDT WEDNESDAY FOR

NORTHERN LA SALLE...SOUTHWESTERN WILL...KANKAKEE...LEE...SOUTHWESTERN

KENDALL...GRUNDY...NORTHERN NEWTON AND CENTRAL JASPER COUNTIES...

WIDESPREAD FLOODING CONTINUES THIS EVENING IN THE WAKE OF THE LATEST

ROUND OF HEAVY RAINFALL TO AFFECT THE AREA MONDAY NIGHT. LOCAL

EMERGENCY MANAGEMENT AND LAW ENFORCEMENT INDICATE VARIOUS FLOODED

ROADS AND LOW LYING AREAS...FROM WHICH WATER WILL ONLY SLOWLY RECEDE

INTO WEDNESDAY.

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Still non river flooding problems ongoing in places hit hard last night...

FLOOD STATEMENT

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

1025 PM CDT TUE JUN 23 2015

LA SALLE IL-WILL IL-KANKAKEE IL-LEE IL-KENDALL IL-GRUNDY IL-

NEWTON IN-JASPER IN-

1025 PM CDT TUE JUN 23 2015

...A FLOOD WARNING REMAINS IN EFFECT UNTIL 1100 AM CDT WEDNESDAY FOR

NORTHERN LA SALLE...SOUTHWESTERN WILL...KANKAKEE...LEE...SOUTHWESTERN

KENDALL...GRUNDY...NORTHERN NEWTON AND CENTRAL JASPER COUNTIES...

WIDESPREAD FLOODING CONTINUES THIS EVENING IN THE WAKE OF THE LATEST

ROUND OF HEAVY RAINFALL TO AFFECT THE AREA MONDAY NIGHT. LOCAL

EMERGENCY MANAGEMENT AND LAW ENFORCEMENT INDICATE VARIOUS FLOODED

ROADS AND LOW LYING AREAS...FROM WHICH WATER WILL ONLY SLOWLY RECEDE

INTO WEDNESDAY.

Some of the worst flooding I've seen here in a loong time.

Definitely don't need anymore rain.

I'd imagine another 2 inches here would put the river flooding in record territory. Fields look like lakes.

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I've been a lurker here for awhile (I own the WilmingtonWx site) and I figured this would make for a suitable first post. Looking at the 00Z CIPS Analogs, the 9th best match is the June 13th, 2013 Ohio Valley Derecho series. That was a wind driven High risk day from the SPC and although the chances that event is matched are slim, the CAMS are showing a very similar - albeit less intense for now - scenario playing out. First an MCS rides from Chicagoland south into Ohio laying out an OFB that triggers a squall line that sweeps further south. Interested to see how the Wednesday MCS affects Thursday's here at CMH.

 

http://www.eas.slu.edu/CIPS/ANALOG/stats.php?reg=EC&model=NAM212&fhr=F048&rundt=2015062400

 

 

Watching the simulated radar, I was thinking the same thing. I have a feeling SW OH is gonna get screwed over just like June 12/13

 

Ignore the rain... couldn't get a blank slate.

post-13588-0-29668700-1435121529_thumb.g

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