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July 17-19 Severe Weather


snowlover2
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Upper-level WV imagery is key to finding these subtle shortwaves that kick off warm-season convection. I haven't really seen any guidance catch onto the activity over Chicago, etc now. 

Going back to 0930Z, look how the cells fire on the leading edge of that darker spot on WV. Model assimilation needs to be able to key in on these features to get it right.

1258319821_ScreenShot2020-07-19at5_50_22AM.thumb.png.6a1ccd692f4804bf2eb433b666041530.png

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8 minutes ago, Powerball said:

Purely anecdotal based on past observations, but in the past I've noticed when there's limited cirrus debris blowing out ahead a complex of storms, they tend to reintensify with the onset of daytime heating.

20200719_1051_sat_irbw_dtw.jpg

 

good observation. obviously depends on a lot of factors, but if the air mass is able to destabilize to surface-based convection owing to the lack of debris clouds, then things can fire up quickly.

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10 minutes ago, purduewx80 said:

good observation. obviously depends on a lot of factors, but if the air mass is able to destabilize to surface-based convection owing to the lack of debris clouds, then things can fire up quickly.

Between that and what you pointed out earlier about the shortwave, I'm definitely feeling better about Detroit's severe weather chances than I did last night. 

None of the models seemingly have a handle of the storms over the southern part of Lake Michigan back through Illinois.

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8 minutes ago, Powerball said:

Between that and what you pointed out earlier about the shortwave, I'm definitely feeling better about Detroit's severe weather chances than I did last night. 

Will have to see the 12Z upper air data to determine capping and the convective trigger temp, but timing out what's here now, this activity will be near Detroit around 17-18Z/1-2ET. Plenty of time to heat up from the looks of it. 

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Models not doing well with the IL/SE IA convection

a couple of severe warmed storms in SE IA

 

cloud tops continue to cool and expand 

 

HRRR trying to catch  up

looks like some training over the south Chicago Suburbs incoming

 

ILX update

 RAPID DEVELOPMENT OF THUNDERSTORMS  
OCCURRED AROUND 5-6 AM, WITH LATEST RADAR MOSAICS SHOWING SEVERAL  
CLUSTERS OF THUNDERSTORMS FROM THE CHICAGO METRO TO PEORIA, WEST  
INTO SOUTH CENTRAL IOWA. MODEL DEPICTIONS HAVE NOT BEEN STELLAR  
WITH THEIR ACCURACY THUS FAR IN THIS SCENARIO, THOUGH THE NSSL WRF  
APPEARS TO HAVE SOMEWHAT OF A HANDLE ON AT LEAST THE ILLINOIS  
PORTION OF THE ACTIVITY.

 

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8 minutes ago, janetjanet998 said:

Models not doing well with the IL/SE IA convection

a couple of severe warmed storms in SE IA

DVN radar indicating ~80mph winds around 3500' with those. 

Curious to see if that cluster rides the front into Chicago towards midday or early afternoon. 

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34 minutes ago, purduewx80 said:

DVN radar indicating ~80mph winds around 3500' with those. 

Curious to see if that cluster rides the front into Chicago towards midday or early afternoon. 

Good t storm with pouring rain here at Griffith now. I hope that second cluster moves more se when it gets to Chi town area.  Under a significant wx advisory for strong storms until 9:30 and a flood advisory until 11:45.  Two inches of rain have already fallen in some areas.

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new development east of the western cluster just west of me...clusters may merge

meanwhile...A quick spin up?

 

0842 AM     TSTM WND DMG     SPERRY                  40.95N 91.15W  
07/19/2020                   DES MOINES         IA   EMERGENCY MNGR     
  
            BILLBOARD DAMAGE AND TWISTED SIGNS BY THE   
            JOHN DEERE DEALERSHIP.   
  

 

 

 

 

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WPC for flooding

ESOSCALE PRECIPITATION DISCUSSION 0506  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
958 AM EDT SUN JUL 19 2020  
  
AREAS AFFECTED...CENTRAL ILLINOIS...NORTHWEST INDIANA  
  
CONCERNING...HEAVY RAINFALL...FLASH FLOODING POSSIBLE  
  
VALID 191358Z - 191858Z  
  
SUMMARY...THUNDERSTORMS PRODUCING HOURLY RATES BETWEEN 1.0-2.0"  
WILL BE CAPABLE OF FLASH FLOODING THIS MORNING ACROSS PORTIONS OF  
CENTRAL ILLINOIS TO NORTHWEST INDIANA.  
  
DISCUSSION...ALONG AND AHEAD OF A SURFACE COLD FRONT ANALYZED FROM  
EASTERN IOWA INTO NORTHERN IOWA, SCATTERED TO NUMEROUS  
THUNDERSTORMS HAVE INTENSIFIED IN THE LAST HOUR PER RECENT RADAR  
RETURNS AND COOLING CLOUD TOPS SEEN IN THE GOES-EAST IR IMAGERY.  
ANOMALOUSLY HIGH MOISTURE HAS POOLED AHEAD OF THE FRONT,  
CHARACTERIZED BY DEWPOINTS IN THE MID 70S AND PWS AROUND 2 INCHES  
(1.75" AT ILX) WHICH IS 2.5-3.0 STANDARD DEVIATIONS ABOVE THE  
CLIMATOLOGICAL MEAN. SBCAPE IS NOW UP TO AROUND 2000 J/KG.  
FINALLY, PER THE LATEST RAP, 850 MB INFLOW INTO THE CONVECTION  
REMAINS 20-30 KTS THIS MORNING.  
  
HI-RES GUIDANCE, INCLUDING LATEST HRRR RUNS, ARE NOT INITIALIZING  
CURRENT ACTIVITY VERY WELL WHICH LEADS TO AN OVERALL LOWER  
CONFIDENCE IN THE EVOLUTION OF THE STORMS THIS MORNING AND  
POTENTIAL FLASH FLOOD THREAT. WITH INCREASING SOLAR INSOLATION AND  
BUILDING INSTABILITY INTO THE REGION, AND THE EXPECTATION THAT THE  
MOISTURE TRANSPORT WILL REMAIN CONDUCIVE, THERE ISN'T ANY STRONG  
REASON FOR THE CONVECTION TO WANE AT THIS POINT IN THE MID TO LATE  
MORNING HOURS, AND THERE'S POTENTIAL FOR SOME BACKBUILDING OR  
REPEATING ROUNDS GIVEN THE MEAN FLOW IS ORIENTED PARALLEL TO THE  
STORM MOTION (AND WATCHING THE SMALLER CLUSTER OF STORMS OVER  
SOUTHEAST IA THAT COULD GROW FURTHER AND TRACK OVER THE SAME  
AREAS).  
  
GIVEN THE HIGH PWS, SUFFICIENT INSTABILITY, AND WARM CLOUD DEPTHS  
ABOVE 4 KM, HOURLY TOTALS BETWEEN 1-2" CAN BE EXPECTED AND TOTALS  
THROUGH 18Z AS HIGH AS 3" IN PLACES. THE 7-DAY PRECIPITATION  
DEPARTURES SHOW SOME ABOVE NORMAL AREAS ACROSS  
CENTRAL/NORTH-CENTRAL ILLINOIS AND IS WHERE SOME OF THE FFGS ARE  
LOWER, AND WITH THE POTENTIAL FOR SOME OF THIS HEAVY RAINFALL TO  
FALL OVER URBAN OR MORE SENSITIVE AREAS, SOME FLASH FLOODING WILL  
BE POSSIBLE.  
  

 

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This area got 3-8 inches last Weds...much of woodford got 6-8 inches then

also 3-4 inches down over southern Grundy and that cluster is still well west....

come on LOT where is the flash flooding warning?

 

BULLETIN - EAS ACTIVATION REQUESTED  
FLASH FLOOD WARNING  
NATIONAL WEATHER SERVICE LINCOLN IL  
1005 AM CDT SUN JUL 19 2020  
  
THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A  
  
* FLASH FLOOD WARNING FOR...  
  MARSHALL COUNTY IN CENTRAL ILLINOIS...  
  WOODFORD COUNTY IN CENTRAL ILLINOIS...  
  NORTHEASTERN TAZEWELL COUNTY IN CENTRAL ILLINOIS...  
  
* UNTIL 100 PM CDT.  
  
* AT 1004 AM CDT, DOPPLER RADAR INDICATED THUNDERSTORMS PRODUCING  
  HEAVY RAIN ACROSS THE WARNED AREA. UP TO THREE INCHES OF RAIN HAVE   
  ALREADY FALLEN FOR PORTIONS OF THE WARNED AREA AND ADDITIONAL   
  HEAVY RAIN OF 1 TO 2 INCHES PER HOUR IS POSSIBLE. FLASH FLOODING   
  IS ONGOING OR EXPECTED TO BEGIN SHORTLY.  
  

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and where is SPC still.... not a good day for the pros

 

BULLETIN - EAS ACTIVATION REQUESTED  
SEVERE THUNDERSTORM WARNING  
NATIONAL WEATHER SERVICE QUAD CITIES IA/IL  
1011 AM CDT SUN JUL 19 2020  
  
THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A  
  
* SEVERE THUNDERSTORM WARNING FOR...  
  PUTNAM COUNTY IN NORTH CENTRAL ILLINOIS...  
  BUREAU COUNTY IN NORTH CENTRAL ILLINOIS...  
  
* UNTIL 1045 AM CDT.  
  
* AT 1011 AM CDT, A SEVERE THUNDERSTORM WAS LOCATED OVER TISKILWA, OR  
  7 MILES SOUTH OF PRINCETON, MOVING EAST AT 55 MPH.  
  
  THIS IS A VERY DANGEROUS STORM!  
  
  HAZARD...80 MPH WIND GUSTS.  
  
  SOURCE...TRAINED WEATHER SPOTTERS.

 

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Finally something

 

  
MESOSCALE DISCUSSION 1274  
NWS STORM PREDICTION CENTER NORMAN OK  
1012 AM CDT SUN JUL 19 2020  
  
AREAS AFFECTED...NORTHERN ILLINOIS/NORTHWESTERN INDIANA  
  
CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE   
  
VALID 191512Z - 191645Z  
  
PROBABILITY OF WATCH ISSUANCE...40 PERCENT  
  
SUMMARY...A CLUSTER OF ONGOING STORMS CONTINUES TO SURGE  
EAST-NORTHEASTWARD ACROSS NORTH-CENTRAL ILLINOIS.  CONTINUATION OF  
LOCALLY SEVERE WIND GUSTS OVER THE NEXT HOUR OR SO COULD WARRANT WW  
ISSUANCE.  
  
DISCUSSION...LATEST RADAR LOOP SHOWS A CLUSTER OF THUNDERSTORMS  
BOWING/SURGING EAST-NORTHEASTWARD ACROSS NORTH-CENTRAL ILLINOIS AT  
50 KT AT THIS TIME.  THE STORMS ARE ONGOING NEAR/JUST AHEAD OF THE  
SURFACE COLD FRONT LYING NORTHEAST TO SOUTHWEST ACROSS THE AREA, AND  
IT APPEARS THAT THE LOCAL CONVECTIVE ENHANCEMENT IS ASSOCIATED WITH  
A REMNANT MCV.  
  
DOWNSTREAM FROM THIS BOWING CLUSTER, PERSISTENT RAINFALL/CONVECTION  
HAS BEEN OCCURRING ACROSS PARTS OF NORTHEAST ILLINOIS AND INTO  
NORTHWESTERN INDIANA, WHICH -- ALONG WITH RELATIVELY DENSE CLOUD  
COVER HINDERING HEATING -- SUGGESTS THAT SEVERE-CALIBER WIND GUST  
POTENTIAL MAY REMAIN TEMPERED/LOCAL AS CONVECTION GRADUALLY  
APPROACHES THE CHICAGO METRO AREA.  HOWEVER, WITH LATEST OBJECTIVE  
ANALYSES MAINTAINING AN AXIS OF 2000 J/KG MIXED-LAYER CAPE, AND  
MODERATE/UNIDIRECTIONAL WESTERLY IN THE 30 TO 40 KT RANGE,  
CONVECTION APPEARS LIKELY TO REMAIN ORGANIZED IN THE SHORT TERM.   
WHILE CURRENT THINKING IS THAT WIND RISK MAY REMAIN LIMITED OVER THE  
NEXT 1 TO 2 HOURS, CONTINUATION OF SEVERE-CALIBER GUSTS INTO REGIONS  
THAT HAVE BEEN RAIN-COOLED COULD PROMPT WW CONSIDERATION.  

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AREA FORECAST DISCUSSION  
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE, IL  
1005 AM CDT SUN JUL 19 2020  
   
MESOSCALE DISCUSSION  
  
1005 AM CDT  
  
CURRENTLY, A COMPACT BOWING LINE OF STORMS (AND ASSOCIATED MCV)   
IS MOVING ACROSS HENRY, BUREAU, STARK, AND NORTHERN MARSHALL   
COUNTIES. THE BOW IS BEING DRIVEN BY A STRONG 80-85KT RIJ SEEN   
NICELY ON OUR RADAR, WITH REPORTS FROM NWS QUAD CITIES CONFIRMING   
SEVERE WINDS ARE REACHING THE SURFACE. GIVEN THE STORM IS MOVING   
INTO AN AIRMASS INTO WHICH HEAVY RAIN AND HENCE COOL AIR HAS BEEN   
FALLING OVER THE PAST FEW HOURS, AND THE LOW-LEVEL SHEAR IS NOT  
OPTIMALLY STRONG TO BALANCE SUCH A STRONG SURGING RIJ/COLD POOL,   
CONFIDENCE IN THE DAMAGING WINDS CONTINUING TO PLOW INTO LA SALLE   
COUNTY IS NOT HIGH EVEN THOUGH A RESERVOIR OF PLENTIFUL   
INSTABILITY EXISTS DOWNSTREAM FROM THE CLUSTER. SO, WHILE THE BOW   
MAY CONTINUE EASTWARD THROUGH NORTHERN ILLINOIS, THE HIGHEST WINDS  
MAY REMAIN ELEVATED AND HENCE LIMIT THE SEVERE WEATHER THREAT TO   
AN ISOLATED BASIS. WE TOUCHED BASE WITH SPC AND THEY AGREE  
- THOUGH IF DAMAGE CONTINUES INTO LA SALLE COUNTY, WE WILL HAVE TO  
ENTERTAIN THE IDEA OF A SEVERE THUNDERSTORM WATCH THROUGH A SMALL  
PORTION OF NORTHERN ILLINOIS.   
  

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RGENT - IMMEDIATE BROADCAST REQUESTED  
SEVERE THUNDERSTORM WATCH NUMBER 384  
NWS STORM PREDICTION CENTER NORMAN OK  
1035 AM CDT SUN JUL 19 2020  
  
THE NWS STORM PREDICTION CENTER HAS ISSUED A  
  
* SEVERE THUNDERSTORM WATCH FOR PORTIONS OF   
  NORTHEAST ILLINOIS  
  NORTHERN INDIANA  
  SOUTHWEST LOWER MICHIGAN  
  NORTHWEST OHIO  
  LAKE MICHIGAN  
  
* EFFECTIVE THIS SUNDAY MORNING AND EVENING FROM 1035 AM UNTIL  
  600 PM CDT.  
  
* PRIMARY THREATS INCLUDE...  
  SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY  
  ISOLATED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE  
  
SUMMARY...A FAST-MOVING COMPLEX OF STORMS OVER NORTHERN ILLINOIS  
WILL APPROACH THE CHICAGO AREA, WHILE OTHER STORMS DEVELOP THIS  
AFTERNOON ALONG A BOUNDARY ACROSS NORTHERN INDIANA.  DAMAGING WIND  
GUSTS ARE THE PRIMARY CONCERN WITH THESE STORMS.

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I just got an alert on my phone of a tornado warning for my region, I just see some weak rotation south of Clifford that is now gone. Its linear "crapped-the-bed" squall line that moved through so I dunno? There were 3 separate tornado warnings including near London and Mitchell (tornado capital of Ontario).

Very dark morning with increasing rumbles of thunder. Imagine if every mid-day in the summer was like this.

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