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2020 Short/Medium Range Severe Thread


Hoosier
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1 hour ago, A-L-E-K said:

lock it in

Capture.JPG

Stranger things have happened. The MCV that developed over Lake Erie a few days ago also had a surface circulation and winds near these levels. 

The MCV already has a surface low co-located with it, and there are 30-35KT gusts N and E of it down in KS this morning. If it is able to maintain some convection near its center, then something along those lines is possible this evening. Similar to the Brown Ocean Effect sometimes allowing tropical systems to intensify over land when you have sufficient heat and moisture flux from the ground. 

 

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1 hour ago, A-L-E-K said:

yeah overnight MCS merger took place in a traditionally bad spot for a us and has spewed a ton of a debris

on the plus side, IR shows tops warming rapidly already and MCV track for later still looks workable

for now I'm more enthused about the potential for excessive rain in the metro. nice signal for a prolonged low level jet focus in the area this evening...including the 12Z NAM (below) and 09/12Z RPM. 

floop-nam-2020071512.850wh.us_mw.gif.099cf52406a9245444b91a4036cd78c6.gif

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excessive rain is what we do best so you're probably on the right track, just like that NAM comes in 2-3 across metro

 

the GOES16 IR loop of the IA diving SE and merging is pretty slick, especially as the remnant is not being lifted back north into the main MCV

 

https://weather.cod.edu/satrad/?parms=regional-midwest-15-96-1-100-1&checked=map&colorbar=undefined

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Mesoscale Precipitation Discussion 0491
NWS Weather Prediction Center College Park MD
1142 AM EDT Wed Jul 15 2020

Areas affected......Central Missouri to central Illinois...

Concerning...Heavy rainfall...Flash flooding possible

Valid 151545Z - 152145Z

Summary...Flash flooding is possible as showers and thunderstorms
expand across central Illinois into north central Missouri.
Rainfall totals between now and 22z are expected to be 1-3 inches
with isolated maxima to 5 inches.  

Discussion...Widespread showers and thunderstorms moving northeast
from northern Missouri are expected to continue moving across
central Illinois through early afternoon.

The northern half of the threat area over central to northern IL
is where a low level warm front centered near 850 mb drifts north,
with focused warm and moisture advection combining with frontal
convergence and 850-700 mb moisture fluxes to produce ascent.

Since the axis of instability is forecast to remain over northern
to central Missouri, redevelopment of cells is expected as
temperatures rise in the warm sector and instability increases
with time.  The 14z RAP indicates potential for mixed layer CAPE
values to increase to 2000-3000 j/kg early this afternoon over 
east central Missouri.  

The precipitable water values are estimated to increase to 2-2.25
inches in the 14z run of the RAP this morning from northeast
Missouri across central Illinois. A closed 850-700 mb low moving
across northern Missouri provides focus for lift in the area of
greatest moisture, along with pre-frontal convergence east of a
quasi stationary surface front near the Iowa/Illinois border and
forming cold front in northeast Missouri. 

With moist, convergent flow centered near 850 mb, convection
should develop in the higher precipitable water axis. Rainfall
rates of 1-2 in/hr will be likely given the high available
moisture in east central Missouri.

The high res models from the 12z NAM Conus Nest, 00z NSSL WRF,
13-14z HRRR, experimental HRRR, and 12z WRF ARW/ARW member 2
forecast clusters of 1-3 inches of rain by 21z, with isolated
maxima to 5 inches. Flash flood guidance in 2-3 inches of rain in
3 hours, so flash flooding will be focused on the more persistent
clusters of storms.

The activity has been developing and moving a little more quickly
to the east northeast than most of the guidance.
The 06-12z Canadian regional GEM has captured the faster east
progression better than the WRF ARW/NMMB/Experimental HRRR.

Also, these models may be depicting heavier rain too far north
into the area of less instability in southeast Iowa.

Petersen

ATTN...WFO...DVN...EAX...ILX...LOT...LSX...SGF...

ATTN...RFC...MBRFC...NCRFC...NWC...

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That just went tornado warned too.

 

BULLETIN - EAS ACTIVATION REQUESTED
TORNADO WARNING
NATIONAL WEATHER SERVICE LINCOLN IL
141 PM CDT WED JUL 15 2020

THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A

* TORNADO WARNING FOR...
  CENTRAL TAZEWELL COUNTY IN CENTRAL ILLINOIS...

* UNTIL 215 PM CDT.

* AT 141 PM CDT, A SEVERE THUNDERSTORM CAPABLE OF PRODUCING A TORNADO
  WAS LOCATED OVER SOUTH PEKIN, OR NEAR PEKIN, MOVING NORTHEAST AT 25
  MPH.

  HAZARD...TORNADO.

  SOURCE...RADAR INDICATED ROTATION.

  IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT 
           SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED. 
           DAMAGE TO ROOFS, WINDOWS, AND VEHICLES WILL OCCUR.  TREE 
           DAMAGE IS LIKELY.

* THIS DANGEROUS STORM WILL BE NEAR...
  PEKIN AROUND 155 PM CDT.
  TREMONT AROUND 205 PM CDT.
  MORTON AND MACKINAW AROUND 215 PM CDT.

OTHER LOCATIONS IMPACTED BY THIS TORNADIC THUNDERSTORM INCLUDE
GROVELAND.

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 INTERSTATE 155 BETWEEN MILE MARKERS 25 AND 31.
 INTERSTATE 474 NEAR MILE MARKER 14.
 INTERSTATE 74 BETWEEN MILE MARKERS 99 AND 103.
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Tornado watch issued at 2:10

Meso update on that watch at 2:13

 

3 mins..got to be the fastest ever

 

TORNADO WATCH NUMBER 373   NWS STORM PREDICTION CENTER NORMAN OK   210 PM CDT WED JUL 15 2020     THE NWS STORM PREDICTION CENTER HAS ISSUED A     * TORNADO WATCH FOR PORTIONS OF   EASTERN ILLINOIS   SOUTHWEST AND CENTRAL MISSOURI     * EFFECTIVE THIS WEDNESDAY AFTERNOON AND EVENING FROM 210 PM   UNTIL 900 PM CDT.     * PRIMARY THREATS INCLUDE...   A FEW TORNADOES POSSIBLE   SCATTERED DAMAGING WIND GUSTS TO 70 MPH LIKELY   SCATTERED LARGE HAIL EVENTS TO 1.5 INCHES IN DIAMETER POSSIBLE     SUMMARY...AN REMNANT MCV AND ITS RELATED STRONG DEEP-LAYER/LOW-LEVEL   WINDS WILL SUPPORT SUPERCELL THUNDERSTORMS AS WELL AS ORGANIZING   LINEAR BOWING STORMS THROUGH MID/LATE AFTERNOON. A FEW TORNADOES ARE   POSSIBLE ASIDE FROM MORE PREVALENT DAMAGING THUNDERSTORM WINDS.   SEVERE HAIL MAY ALSO OCCUR.  

 

MESOSCALE DISCUSSION 1234  
NWS STORM PREDICTION CENTER NORMAN OK  
0213 PM CDT WED JUL 15 2020  
  
AREAS AFFECTED...WEST-CENTRAL/CENTRAL IL  
  
CONCERNING...TORNADO WATCH 373...  
  
VALID 151913Z - 152015Z  
  
THE SEVERE WEATHER THREAT FOR TORNADO WATCH 373 CONTINUES.  
  
SUMMARY...ALL SEVERE HAZARDS, INCLUDING LARGE HAIL AND A TORNADO OR  
TWO, ARE POSSIBLE ALONG THE NORTHERN PERIPHERY OF TORNADO WATCH 373  
FOR THE NEXT HOUR OR TWO.  
  
DISCUSSION...RECENT SURFACE ANALYSIS PLACES A LOW NORTH OF COU IN  
CENTRAL MO, WITH A WARM FRONT EXTENDING EAST-NORTHEASTWARD ACROSS  
CENTRAL IL. SHOWERS AND THUNDERSTORMS HAVE BEEN ONGOING ACROSS  
WEST-CENTRAL AND CENTRAL IL NORTH OF THIS WARM FRONT FOR THE PAST  
FEW HOURS. HOWEVER, RECENT RADAR IMAGERY HAS SHOWN A STRENGTHENING  
TREND WITH A FEW OF THESE STORMS, PARTICULARLY THE STORM IN TAZEWELL  
COUNTY. AS EVIDENCED BY THE 17Z ILX SOUNDING, INSTABILITY IS MODEST  
IN THIS REGION, BUT VERTICAL SHEAR IS STRONG. AS A RESULT, MORE  
PERSISTENT UPDRAFTS SHOULD BE ABLE TO ORGANIZE/ROTATE, CONTRIBUTING  
TO A SLIGHTLY GREATER SEVERE THREAT THAN WOULD OTHERWISE BE  
SUPPORTED BY THE INSTABILITY. ADDITIONALLY, INITIALLY ELEVATED  
STORMS (LIKE THOSE WEST OF TAZEWELL COUNTY) MAY BE ABLE TO  
TRANSITION TO MORE SURFACE-BASED IF MID-LEVEL ROTATION PERSISTS  
AND/OR AS A RESULT OF INTERACTION WITH THE WARM FRONTAL ZONE.  
CONSEQUENTLY, ALL SEVERE HAZARDS ARE POSSIBLE, INCLUDING LARGE HAIL  
AND A TORNADO OR TWO.  

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Severe threat will easily miss south of the area the rest of today, but rain/t’storms congealing across DVN and ILX CWA’s will spread across the area this evening. Without widespread/heavier/training t’storms, amounts should be kept in check though, unless south of I-80.


.

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BULLETIN - EAS ACTIVATION REQUESTED  
TORNADO WARNING  
NATIONAL WEATHER SERVICE LINCOLN IL  
407 PM CDT WED JUL 15 2020  
  
THE NATIONAL WEATHER SERVICE IN LINCOLN HAS ISSUED A  
  
* TORNADO WARNING FOR...  
  NORTH CENTRAL MCLEAN COUNTY IN CENTRAL ILLINOIS...  
  
* UNTIL 415 PM CDT.  
  
* AT 406 PM CDT, A CONFIRMED TORNADO WAS LOCATED JUST EAST OF   
  GRIDLEY, OR 14 MILES SOUTHWEST OF PONTIAC, MOVING NORTHEAST AT 20   
  MPH.  
  
  HAZARD...DAMAGING TORNADO.  
  
  SOURCE...WEATHER SPOTTERS CONFIRMED TORNADO.  
  
  IMPACT...FLYING DEBRIS WILL BE DANGEROUS TO THOSE CAUGHT WITHOUT   
           SHELTER. MOBILE HOMES WILL BE DAMAGED OR DESTROYED.   
           DAMAGE TO ROOFS, WINDOWS, AND VEHICLES WILL OCCUR.  TREE   
           DAMAGE IS LIKELY.  
  
* THIS TORNADIC THUNDERSTORM WILL REMAIN OVER MAINLY RURAL AREAS OF  
  NORTH CENTRAL MCLEAN COUNTY.  

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Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
348 PM CDT Wed Jul 15 2020

.MESOSCALE DISCUSSION...
348 PM CDT

Watching an impressively wound-up convectively-enhanced Mesoscale
Convective Vortex lifting northeastward out of Central Illinois
this afternoon. This feature seems to have been born out of
convection last night across the Texas and Oklahoma Panhandles.
Typically the more well-developed MCV`s carry with them a flow
enhancement, and that certainly seems to be the case here.
Lincoln`s special 17z sounding sampled 50-60 kts of flow in the
550-400 mb layer, and this is supporting effectively deep layer
shear values of about 50 kts into our southern counties. While
overall instability values aren`t high (likely due to somewhat
pronounced mid-level warming noted on the aforementioned
sounding), recent objective SPC mesoanalysis depicts a corridor of
150 to nearly 200 J/kg of 0-3 km MLCAPE, more than sufficient in
concert with the elevated shear values to locally augment low and
mid- level updraft accelerations. It is thus not a surprise to see
an established supercell northwest of Bloomington.

The concern locally here is that even in the face of limited
instability from a typical sense (read: MLCAPE), a hodograph run
using KILX`s radar and the rather deviant storm motion on the
right-motion vector and breezy southeast winds yields 0-3 km SRH
values nearing 400-450 m2/s2. As a result, we did recently
coordinate a small/targeted tornado watch for our far southwestern
counties to highlight this localized threat developing over the
next few hours. Corridor of localized damaging wind gusts and some
hail threat will also exist in this region, although the limit on
the hail potential should be capped a bit by the muted mid-level
lapse rates. The severe threat will likely have a harder time
building too much farther northwest than I-55 given the expansive
and persistent cloud cover today holding temperatures down, but
peeks of sunshine south and east of there may help locally boost
the severe potential through this afternoon and into the evening.

Finally, we are still monitoring at least a localized flash flood
threat into the evening as rather slow storm motions and at least
some potential for a bit of training will be possible within a
richly-moist atmosphere. Already seeing some 2-3" rainfall amounts
out of the storms upstream. Greatest signal for this potential is
across roughly the southeastern half of the CWA.

Carlaw
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worst flooding in quite a while here

2.85 inches on 1 hour at the airport last ob if it is correct

5 total

City and SE metro hit hard

Peoria, Pekin, East Peoria. Morton  and smaller towns hit hard

edit:  several on facebook reporting 6 inch rain gauge overflowing NW side of Morton

 

 

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47 minutes ago, janetjanet998 said:

0640 PM     HEAVY RAIN       2 N PEORIA INTERNATIONA 40.70N 89.68W   
07/15/2020  M6.48 INCH       PEORIA             IL   TRAINED SPOTTER   
  
            RAIN SINCE 1PM  

Airport measured 5.19" including 2.85" in one hour and 1.41" in another hour

KPIA 151954Z 06008KT 3/4SM R04/2200V5500FT +TSRA BR FEW007 BKN021 OVC027 21/19 A2991 RMK AO2 LTG DSNT ALQDS SLP125 P0141 T02110194

KPIA 152254Z 35006KT 3/4SM R04/2800VP6000FT +RA BR SCT002 OVC015 23/21 A2981 RMK AO2 LTG DSNT ALQDS TSE22 SLP092 P0285 T02280211

KPIA 152354Z 07006KT 10SM OVC004 23/21 A2982 RMK AO2 LTG DSNT E AND SE RAE40 CIG 003V007 SLP094 P0016 60515 T02280211 10239 20211 55024

 

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