Severe Threat June 11-13

[SchaumburgStormer]

 

Funny how things escalate when there is not crap-vection to ruin the day.

[jojo762]

Wow... First High-Risk of the year for the Great Lakes, and not for the Central Plains, and it's for damaging winds, not tornadoes... I don't remember seeing a high-risk base on damaging wind probabilities in a long time.

[Chicago Storm]

It should be noted that Carbin was part of the MD.

[A-L-E-K]

It should be noted that Carbin was part of the MD.

 

 

[hm8]

Dtx update

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI

1049 AM EDT WED JUN 12 2013

UPDATE

THE FORECAST CONCERNS TODAY OBVIOUSLY REVOLVE AROUND THE POTENTIAL

FOR SEVERE WEATHER ACROSS THE SOUTHERN THIRD OF THE FORECAST AREA.

AS IS OFTEN THE CASE...THE SEVERE WEATHER POTENTIAL OVER SRN MI IS

NOT VERY CLEAR CUT AND CARRIES A LOT OF UNCERTAINTY.

THE OVERNIGHT CONVECTION OVER IOWA ALLOWED A MESO SCALE VORTICITY

MAX TO DEVELOP...WHICH THE LATEST SATELLITE DATA SUGGESTS IS NOW

ROLLING ACROSS SRN WI. DESPITE WARMING CLOUD TOPS THIS MID LEVEL

IMPULSE WILL COMBINE WITH GOOD LOW LEVEL MOISTURE ADVECTION TO

SUSTAIN AT LEAST SCATTERED TO NUMEROUS SHOWERS ACROSS THE SOUTHERN

HALF OF THE FORECAST AREA WELL INTO THE AFTERNOON. THE SURFACE WARM

FRONT IS STILL EXPECTED TO LIFT TOWARD THE MI BORDER THIS

AFTERNOON. 12Z RAOBS ACROSS THE MIDWEST SHOW A DEEP ELEVATED MIXED

LAYER WHICH IS NOW OVERSPREADING THE OHIO VALLEY AND SRN GREAT

LAKES. THIS WILL PROVIDE A SUBSTANTIAL CAPPING INVERSION BY EARLY

AFTERNOON. THE CAP WILL HOWEVER ALLOW MODERATE TO HIGH INSTABILITY

TO DEVELOP SOUTH OF THE WARM FRONT THIS AFTERNOON. THE LOW LEVEL

FLOW WILL BACK AND STRENGTHEN DURING THE AFTERNOON AS THE DEEPER

MID LEVEL IMPULSE ROTATES INTO THE UPPER MS VALLEY. THIS WILL

ADVECT LOW TO MODERATE ELEVATED INSTABILITY INTO SRN MI LATER THIS

AFTERNOON...NORTH OF THE SFC WARM FRONT. THE LATEST MODEL

INDICATIONS ARE THAT THE BETTER INSTABILITY /0-3KM MU CAPE OVER

1500 J/KG/ WILL EXTEND ALONG AN AXIS FROM LANSING TO DETROIT BY

00Z THIS EVENING. IF THE CLOUDS BREAK ENOUGH LATE IN THE

DAY...SOME SURFACE BASED CAPE ALONG A SECONDARY THERMAL TROUGH

AXIS MAY IGNITE CONVECTION IN THIS REGION. DEEP LAYER SHEAR UP

TO 60 KNOTS AND GOOD LOW LEVEL CYCLONIC CURVATURE IN THE HODOGRAPH

WILL BE SUPPORTIVE OF SUPPER CELLS. IT APPEARS THE MOST PROBABLE

TIME PERIOD FOR THIS CONVECTION WILL NOT BE UNTIL 22Z TO 03Z.

AS LARGER SCALE DYNAMICS INCREASE LATE THIS EVENING...CONVECTION

SHOULD GROW UPSCALE AND EVOLVE INTO A FORWARD PROPAGATING LINEAR

MCS. THE DEGREE OF INSTABILITY IS SUPPORTIVE OF THE DEVELOPMENT OF

A LARGE COLD POOL WITH THIS MCS...SO RAPID FORWARD PROPAGATION AND

DAMAGING WINDS ARE A CONCERN. THE LOCATION OF INITIATION WILL BE

KEY AS TO WHETHER THIS MCS WILL IMPACT THE EXTREME SOUTHERN

SECTIONS OF SE MI OR REMAIN SOUTH OF THE MI BORDER. IF THIS SYSTEM

DEVELOPS OVER NORTHERN ILLINOIS THIS EVENING... LOCATIONS ALONG

AND SOUTH OF THE I-94 CORRIDOR STAND A CHANCE OF BEING IMPACTED BY

THE NORTHERN SECTION OF THE MCS LATE IN THE EVENING. THERE

CERTAINLY IS A CHANCE THAT THE DYNAMICS WILL FORCE DEVELOPMENT

FARTHER SOUTH...IN WHICH CASE THE SEVERE THREAT WILL REMAIN SOUTH

OF THE FORECAST AREA.

SO IN SHORT...THERE IS A SLIGHT RISK OF SEVERE WEATHER FOR

LOCATIONS ALONG AND SOUTH OF A LANSING TO DETROIT LINE THIS

EVENING. TO THE NORTH OF THIS LINE...ANY LATE DAY CLEARING COULD

LEAD TO ENOUGH INSTABILITY TO CREATE SOME ISOLATED STRONG TO

SEVERE STORMS. THE CONFIDENCE OF THIS OCCURRING IS QUITE LOW. OVER

THE NEXT HOUR...THERE WILL BE AN UPDATE TO THE FORECAST AND HWO

MAINLY TO REFINE THE MOST PROBABLE TIME OF SEVERE WEATHER AND MAKE

SOME MINOR UPDATES TO REFLECT THE LATEST FORECAST THOUGHTS.

Sent from my HTCONE using Tapatalk 2

[Chicago WX]

First High Risk of the year, for anywhere, correct?

Steam bath here, 80/71 at 11:00am.

[hm8]

Weenie, I assume?

Sent from my HTCONE using Tapatalk 2

[Nighthawk]

Long time lurker - first time posting.

Just a quick question - when was the last time the LOT CWA was placed under a high risk? It seems like it's been a couple of years, at the very least.

[MidwestChaser]

[A-L-E-K]

I am surprised they didn't wait to issue something more focused immediately downstream of the eventual bowing MCS.  The outlined area is rather large.

[Chicago Storm]

Weenie, I assume?

Sent from my HTCONE  2

No, not at all.

[Chicago Storm]

yeah...I suspect 70% sun strength at or around noon down here...still headed west joe?

Somewhere north of I-80 in IL is where I'll go. Exactly where has yet to be determined.

[A-L-E-K]

overcast starting to thin over Chicagoland.

[snowlover2]

Wow a high risk coming out. Got nothing but sun here 83/71.

[Chicago Storm]

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1043 AM CDT WED JUN 12 2013

MESOSCALE DISCUSSION

1042 AM CDT

...WIDESPREAD SEVERE WEATHER OUTBREAK ACROSS THE REGION EXPECTED
LATE THIS AFTERNOON AND EVENING INCLUDING TORNADIC POTENTIAL IN
NORTH CENTRAL IL LATE THIS AFTERNOON...

SEVERE WEATHER THREAT CONTINUES WITH OBSERVATIONAL TRENDS HINTING
MORE AT PRECISE EVOLUTION AND TIMING.

WHAT LEFTS OF OVERNIGHT DECAYING MCS IS MOVING FROM SOUTHEAST WI
OVER LAKE MI. VISIBLE SATELLITE AND REGIONAL RADAR MOSAIC
INDICATE SOME BRIEF SUPPRESSION BEHIND THIS WHILE THERE IS AN AXIS
EXTENDING SOUTHWARD ON RADAR OF LIKELY SOME MID-LEVEL CONVERGENCE.
THERE HAS NOT BEEN ANY DEVELOPMENT ALONG THIS THUS FAR BUT CANNOT
RULE OUT A FEW ELEVATED STORMS THROUGH 3 PM OR SO ACROSS FAR
NORTHERN AND NORTHEAST IL.

THE SURFACE LOW PRESSURE IS DEVELOPING NORTHEASTWARD INTO SOUTHWEST
AND CENTRAL IA AS OF 10 AM WITH A WARM FRONT EVOLVING EAST
NORTHEAST FROM THERE. THIS LOOKS TO BE FROM NEAR WATERLOO IA TO
SAVANNA IL AND THEN BECOMING MORE ILL-DEFINED EAST OF THERE INTO
THE CWA. DEW POINTS IN THE LOWER 70S ARE ADVECTING UP TO THIS
BOUNDARY WITH WINDS STRONGLY BACKED TO THE NORTH OF THIS. THERE
HAS BEEN GROWTH IN THE CU ACROSS IA NEAR THIS DEVELOPING FRONT.
AS THE MAIN VORT MAX AND MID-LEVEL SPEED MAX MOVE EAST FROM
EASTERN SD/NORTHEAST NE...DEVELOPMENT OF ROBUST CONVECTION IS
HIGHLY LIKELY BY MID AFTERNOON ACROSS NE IA/SW WI/NW IL. SUPERCELL
DEVELOPMENT WOULD BE A FAVORED MODE ALONG AND IMMEDIATELY NORTH OF
THE WARM FRONT. FURTHER NORTH AND NORTHEAST FROM THE TWIN CITIES
TO MILWAUKEE...ELEVATED CONVECTION MAY INCREASE. ALL OF THIS IS
SLIGHTLY FURTHER NORTH THAN EARLIER ANTICIPATED...BUT THE SEVERE
WEATHER THREAT HAS NOT DIMINISHED FOR OUR AREA...JUST FOCUSED MORE
SO IN THE LATE AFTERNOON AND EVE.

GIVEN THE ANTICIPATED EVOLUTION MENTIONED ABOVE WHICH HAS THE
SUPPORT OF THE RAP AND SEVERAL CONVECTIVE-ALLOWING MODELS...NORTH
CENTRAL IL WILL LIKELY BE UNDER THE GUN LATE THIS AFTERNOON. THIS
INCLUDES THE ROCKFORD AREA DURING RUSH HOUR AS STORMS EVOLVE
EASTWARD IN A FAVORED COMBINATION OF DISCRETE TO SMALL SCALE
CLUSTERS. TORNADIC POTENTIAL WILL CERTAINLY EXIST WITH THESE GIVEN
THE HELICITY RICH AIR NEAR THE BOUNDARY AND ANTICIPATED SURFACE-
BASED CAPE. CONVECTIVE TEMPERATURES FOR THIS ARE FORECAST TO BE
AROUND 80 DEGREES ON THE RAP. WHILE TEMPERATURE TRENDS HAVE BEEN
SLOW TO CLIMB ACROSS THE AREA THUS FAR...SOME THINNING OF THE
CLOUDS AND THE NORTHWARD PUSH OF THE WARM SECTOR SHOULD ALLOW THAT
TO OCCUR.

THE EVENING TIME PERIOD SHOULD SEE THE MOST COVERAGE OF SEVERE
CONVECTION IN THE FORECAST AREA AND WILL BE THE PRIME TIME FOR
CHICAGOLAND. THE LOW-LEVEL JET IS FORECAST TO INCREASE TO 40-50 KT
AND POINT INTO THE ONGOING CONVECTION. SOME SCATTERED CONVECTIVE
DEVELOPMENT...POTENTIALLY SEVERE AND SURFACE BASED...EAST AND
SOUTH OF THIS IS FAVORED DURING THE EVE. SUFFICIENT DEEP LAYER
SHEAR AND RICH LOW-LEVEL MOISTURE WILL OFFER AMPLE WIND THREAT
WITH THE ORGANIZED CONVECTIVE CLUSTERS. WITH THE SURFACE LOW
PROJECTED TO TRACK EAST NEAR THE I-88 CORRIDOR...THERE IS
INCREASING LIKELIHOOD THAT THE MAIN MCV/MCS WILL DEVELOP NEAR THIS
CORRIDOR AS WELL. A MAJORITY OF THE EXPLICIT GUIDANCE DOES
INDICATE THIS. VERY HEAVY RAINFALL AND AN ENHANCED WIND THREAT
WILL EXIST WITH THIS...WHICH WOULD LIKELY IMPACT CHICAGO IN THE
6-10 PM TIME FRAME. 
 

[hm8]

Weenie, I assume?

Sent from my HTCONE  2

No, not at all.

So a conservative forecaster writing about a high risk in the md? Or something else I'm missing entirely.

Sent from my HTCONE using Tapatalk 2

[mjwise]

The only way to get a wind-driven high risk day is with a 60% WIND group. Jeepers. Would be fun to chase, but NIMBY please. Looks like we'll only get cold pool rains up here late into tonight from the looks at the later RAP runs.

[Bryan Wood]

Wow... First High-Risk of the year for the Great Lakes, and not for the Central Plains, and it's for damaging winds, not tornadoes... I don't remember seeing a high-risk base on damaging wind probabilities in a long time.

 

In our area, besides June 29...I believe 10-26-2010.

 

http://www.spc.ncep.noaa.gov/exper/archive/event.php?date=20101026

[Chicago Storm]

So a conservative forecaster writing about a high risk in the md? Or something else I'm missing entirely.

Sent from my HTCONE  2

A good convective forecaster writing about a high risk in the MD.

[Brewers]

Sun starting to peak through the clouds here

[Gilbertfly]

DVN using PDS verbage in their SWS...

 

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE QUAD CITIES IA IL
1052 AM CDT WED JUN 12 2013

...HIGH RISK FOR SEVERE WEATHER ACROSS EASTERN IOWA AND NORTHWEST
ILLINOIS THIS AFTERNOON...

INGREDIENTS ARE COMING TOGETHER SUPPORTING A HIGH THREAT FOR SEVERE
THUNDERSTORMS WITH DAMAGING WINDS...LARGE HAIL AND TORNADOES OVER
MUCH OF EASTERN IOWA...WEST CENTRAL AND NORTHWEST ILLINOIS THIS
AFTERNOON.

SUPERCELL THUNDERSTORMS ARE EXPECTED TO DEVELOP BETWEEN NOON AND 3
PM OVER PORTIONS OF EASTERN IOWA AND NORTHWEST ILLINOIS. THESE
STORMS WILL BE CAPABLE OF PRODUCING WINDS OVER 70 MPH...LARGE HAIL
AND TORNADOES...WITH MOVEMENT TO THE EAST AROUND 40 TO 50 MPH.
INDIVIDUAL STORMS ARE EXPECTED TO ORGANIZE INTO A LINE OF STORMS
WITH WIDESPREAD DAMAGING WIND AS THEY EXIT EAST ACROSS
NORTHERN ILLINOIS FROM MID TO LATE AFTERNOON.

A TORNADO WATCH WILL LIKELY BE ISSUED FOR THE AREA THIS AFTERNOON.
WHILE THE THREAT OF SEVERE WEATHER IS NOT IMMINENT...THIS IS A
POTENTIALLY DANGEROUS SITUATION AND YOU SHOULD MAKE PLANS FOR WHERE
YOU WILL TAKE SHELTER IF WARNINGS ARE ISSUED. CLOSELY MONITOR NOAA
WEATHER RADIO OR LOCAL MEDIA OUTLOOKS FOR FURTHER UPDATES AND
WARNINGS.

 

 

[Chitown Storm]

Sun breaking through the clouds here about 25 mi west of Chicago. Still pretty overcast though.

[Chargers09]

The only way to get a wind-driven high risk day is with a 60% WIND group. Jeepers. Would be fun to chase, but NIMBY please. Looks like we'll only get cold pool rains up here late into tonight from the looks at the later RAP runs.

Where are you located?

[A-L-E-K]

Sun breaking through the clouds here about 25 mi west of Chicago. Still pretty overcast though.

 

 

another hour or two to go

[Geos]

Cloudy still here. Definitely a marine influence in place. I would imagine heavy rain and maybe wind is the greatest threat up this way today. - unless the warm front were to shoot north.

[mjwise]

Where are you located?

 

Pretty much KARB. I'm less than a 1/4 mile from that terminal as I sit here. At least my read is the severe possibilities aren't particularly good and that a period of rain is more likely. Hopefully not going to be a total shutout the way last year's derecho was though.

 

EDIT: Even we're at 72/65 here and we haven't seen so much as a peep of sun with clearing occurring in SW MI, so there may be possibilities here yet.

[Drizzle]

Sun starting to break through here in Dekalb.

[Chargers09]

Pretty much KARB. I'm less than a 1/4 mile from that terminal as I sit here. At least my read is the severe possibilities aren't particularly good and that a period of rain is more likely. Hopefully not going to be a total shutout the way last year's derecho was though.

EDIT: Even we're at 72/65 here and we haven't seen so much as a peep of sun with clearing occurring in SW MI, so there may be possibilities here yet.

I think those of is south of 59 are really in the game. I wouldn't worry.

[Castaway]

[TimChgo9]

Wow. 

 

High Risk for the area. This the first High Risk in quite some time, right? 

 

Getting prepared for some rocking and rolling later.