Severe weather: 5/10-5/12 Plains/Midwest

[Chicago Storm]

Standard Broyles outlook.

[Disc]

A couple more soundings from C IA for posterity. Don't remember seeing a STP of 14 on one of these before.

 

[tornadotony]

A couple more soundings from C IA for posterity. Don't remember seeing a STP of 14 on one of these before.

 

I do, but only once w/o thermonuclear capping.

[chase_stormz]

Where i Central IA are those located?

 

A couple more soundings from C IA for posterity. Don't remember seeing a STP of 14 on one of these before.

 

[jut2005]

Anyone have any opinions on whether or not the Iowa City area is going to see any major tornadoes?  I see we are on the edge of the 45% hatched area but all the models I look at seem to have the tornado threat just to our West(note I have no weather forecasting experience).  The tornado threat seems to quickly drop off as you head east  of Des Moines towards the Quad Citites.  Is IC looking at more of a hail/wind threat than a tornado threat?

 

Thanks in advance for your comments.  I will be glued to this forum for the next 48 hours and enjoy everyones opinions. 

[Disc]

stormchaserck19, on 10 May 2014 - 2:22 PM, said:

Where i Central IA are those located?

 

First one is Boone, IA. Second is Carroll, IA.

[Jonbo]

I may not have to go far tomorrow if I choose to head out (or not even have to leave   ) and chase a few. Been awhile since I've been truly concerned about what could happen IMBY.

[andyhb]

*4 km NAM image*

 

That secondary low it pops up there would be bad news, Omaha is right under the gun if the front retreats that far north.

[chase_stormz]

So it looks like the ceiling for an Iowa tornado outbreak is 4/8/1999. That's gonna be awfully hard to match... 

[andyhb]

So it looks like the ceiling for an Iowa tornado outbreak is 4/8/1999. That's gonna be awfully hard to match... 

 

Well it wouldn't be incredibly hard to match if you have a few supercells go to absolute town near the WF given the ridiculous environment that is there. This event might not be prolific as the D2 outlook seems to suggest, but in terms of intensity, all the ingredients look to be there should the following work themselves out. The first question is leftover convection from today/tonight and then second how far north the WF gets and then last, but certainly not least: storm coverage itself once zero hour gets there.

[chase_stormz]

Very true. What's your thought on initiation, and when that will occur? And where?

Well it wouldn't be incredibly hard to match if you have a few supercells go to absolute town near the WF given the ridiculous environment that is there. This event might not be prolific as the D2 outlook seems to suggest, but in terms of intensity, all the ingredients look to be there should the following work themselves out. The first question is leftover convection from today/tonight and then second how far north the WF gets and then last, but certainly not least: storm coverage itself once zero hour gets there.

[andyhb]

Very true. What's your thought on initiation, and when that will occur? And where?

 

Well that's kind of dependent on where everything sets up, the triple point seems like a good place to start. I'm not going to get into timing more specifically since there's still a number of uncertainties, but obviously mid afternoon would be favoured as CIN weakens.

[chase_stormz]

Do you personally believe we will see a couple of sups out along the WF in IA? SPC seems fairly confident we will but I'm not as certain with a lack of forcing. 

Well that's kind of dependent on where everything sets up, the triple point seems like a good place to start. I'm not going to get into timing more specifically since there's still a number of uncertainties, but obviously mid afternoon would be favoured as CIN weakens.

[andyhb]

Do you personally believe we will see a couple of sups out along the WF in IA? SPC seems fairly confident we will but I'm not as certain with a lack of forcing. 

 

Not as confident as I'd like to be at this juncture, put it that way. I mentioned this somewhere else, but a concern is cells initiating near the triple point and then moving ENE into IA through the afternoon/evening with the ambient environment spreading/becoming rapidly more impressive along with them and ahead of them.

[ZackH]

We have our first mesoscsle model concern... the SPC WRF doesn't break out precip in the highest threat zone. Wouldn't worry about the hi res models this far out, though. I don't see forcing being a concern. Depending on what model you're looking at, you have 45 to 55 knot 500mb winds well into Iowa by 21z. That's well ahead of the triple point.

Sent from my LG-LS980 using Tapatalk

[tornadotony]

We have our first mesoscsle model concern... the SPC WRF doesn't break out precip in the highest threat zone. Wouldn't worry about the hi res models this far out, though. I don't see forcing being a concern. Depending on what model you're looking at, you have 45 to 55 knot 500mb winds well into Iowa by 21z. That's well ahead of the triple point.

Sent from my LG-LS980

The 00z run of that model the night before 4/28 had zero convection in northern AL after 18z.  Whoopsies.

[ZackH]

Exactly... I have just seen people irrationally freaking out about it already

Sent from my LG-LS980 using Tapatalk

[andyhb]

Also tomorrow could be a day where that radar hole in N MO/S IA really rears its ugly head again (today also could be).

 

Just looking at mesoanalysis, the RAP currently appears to be underestimating SB/MLCAPE by a decent margin especially in eastern KS and western MO.

[JoMo]

Also tomorrow could be a day where that radar hole in N MO/S IA really rears its ugly head again (today also could be).

 

Just looking at mesoanalysis, the RAP currently appears to be underestimating SB/MLCAPE by a decent margin especially in eastern KS and western MO.

 

Both the RAP and HRRR have a low dewpoint problem. I've watched it with each setup that was in my area and each time the RAP/HRRR mix out the dewpoints too much. I'm not sure if it's a model issue or if the drought is causing the issue. 

[Chinook]

Here's something that's going on now:  there's a splitting cell hear Holton KS, that popped up within the last hour.

[andyhb]

Both the RAP and HRRR have a low dewpoint problem. I've watched it with each setup that was in my area and each time the RAP/HRRR mix out the dewpoints too much. I'm not sure if it's a model issue or if the drought is causing the issue. 

 

It's definitely a model issue since the RAP tends to have problems with overestimating temperatures (which also leads to its LCL heights being too high like 5/19/13).

[TheWeatherPimp]

Also tomorrow could be a day where that radar hole in N MO/S IA really rears its ugly head again (today also could be).

 

Just looking at mesoanalysis, the RAP currently appears to be underestimating SB/MLCAPE by a decent margin especially in eastern KS and western MO.

 

It's really surprising how bad some of the radar holes are and how long they've let them go without working towards a resolution.

[Hvward]

Cells east and se of Wichita really look ominous.  45,000k+ tops and starting to show some signs of rotation.  

[andyhb]

It's really surprising how bad some of the radar holes are and how long they've let them go without working towards a resolution.

 

Well money is obviously one of the problems, but the radar holes in the Arklatex and the one in N MO/S IA are significant considering how tornado prone those areas are (there's also one in the Arklamiss).

 

Case in point, that's a pretty nasty looking cell moving towards Albany, MO.

[andyhb]

If we get something like what is happening today over IA and MO tomorrow, there will be some serious problems to say the least.

 

Also TOP has a much stronger worded (and very well written) discussion with their most recent AFD.

By mid morning, expect all elevated thunderstorms to have moved
north out of the Nebraska border with warm air and a cap around 850
HPa. Also expect substantial moisture transport under this cap,
bringing surface dewpoints into the upper 60s and perhaps
approaching 70. This will also likely bring a layer of stratus
below the cap. Expect this stratus to be thickest in eastern KS,
but should at least scatter out by early afternoon, and perhaps
clear out completely over north central KS by mid afternoon.
Thus expect ample heating while the frontal boundary sets up on a
SSW to NNE axis in central KS, likely near the HWY 81 corridor.
Storms will develop in earnest by mid (perhaps early?) afternoon
along this front and will rapidly become severe. Given the
expected frontal orientation and the cap in place, expect that
some of these storms through early evening may have success in
remaining somewhat isolated and then having a storm motion off of
the frontal boundary and into the warm sector. This seems to be
most favored across northern KS. These storms would be capable of
very large hail. Fairly large, looped hodographs also suggest a
tornado threat as storms become well organized, although at least
in the afternoon, the warm temperatures may limit that potential
somewhat as LCL`s may be too high for enhanced tornado potential.
Regardless...the threat is there.

Over time into the evening, expect storms to continue to develop
along the frontal boundary but should begin to congeal more and more
into line segments perhaps with embedded supercells. This is where
the forecast gets a bit more tricky. Deep layer shear remains
impressive, and low level shear strengthens significantly in the
evening as the LLJ intensifies across the region. Should the
atmosphere remain quite unstable through the night...and feel that
it will...could see supercell structures persist well after dark and
perhaps into the early morning hours. Model sounding suggest that
they will become slightly elevated, but with such a shallow
inversion that it can not be trusted. Current thoughts are that the
tornado potential will increase early evening as the LLJ begins to
increase, and by late evening may continue to increase but only if
supercell structures can be maintained. The bottom line is to expect
these storms to be intense across the local forecast area,
especially north of the Kansas Turnpike through mid evening but
possibly across the entire area into the early morning hours. In
addition, heavy rainfall will be a possibility along with some
training of storms, and while much of the area is quite dry there
is some potential for flash flooding.

 

OAX:

BY SUNDAY AFTERNOON CONDITIONS LOOK TO DETERIORATE QUICKLY.
SURFACE DEW POINTS RISE QUICKLY INTO THE LOW/MID 60S IN RESPONSE
TO STRONG MOISTURE TRANSPORT UNDER THE MODEST LOW-LEVEL JET. THIS
SUBSTANTIAL INCREASE IN MOISTURE WILL GIVE WAY TO MIXED LAYER CAPE
VALUES AOA 2000 J/KG. THIS COMBINED WITH 0-6 KM SHEAR VALUES OF
40-60 KNOTS AND THE NORTHWARD ADVANCING SURFACE WARM FRONT WILL
SET THE STAGE FOR AN ACTIVE SEVERE WEATHER NIGHT. ALL SEVERE
THREATS WILL BE SEEN...TORNADOES...LARGE HAIL AND STRONG WINDS AS
SUPERCELLS DEVELOP UNDER THE STRENGTHEN LOW-LEVEL JET.
FINALLY...GIVEN THE STRONG MOISTURE TRANSPORT EXPECTED AND THAT
THE MID-LEVEL FLOW WILL BE GENERALLY PARALLEL TO THE SURFACE
FRONT...VERY HEAVY RAIN AND FLOODING WILL BE POSSIBLE. SEE THE
HYDROLOGY DISCUSSION FOR MORE INFORMATION ON THIS.

 

ICT:

FOCUS THEN SHIFTS TO SUNDAY AFTERNOON/EVENING AS THE STRONG
COLD FRONT OVERTAKES THE DRY-LINE ACROSS CENTRAL KANSAS.
INTENSE SURFACE HEATING WITH TEMPERATURES AROUND 90F WILL
LEAD TO A VERY UNSTABLE AIRMASS JUST EAST OF THE FRONT...WITH
VERY IMPRESSIVE DEEP LAYER SHEAR. WHILE THE ENVIRONMENT WILL
BE SUPPORTIVE OF SUPERCELLS IN THE FIRST FEW HOURS OF STORM
INITIATION...FLOW ALOFT BECOMING MORE PARALLEL WITH THE
COLD FRONT SHOULD TEND TO RESULT IN TRANSITION TO A LINEAR
MODE AS THE EVENING PROGRESSES ON SUNDAY. THAT SAID...BESIDES
THE RISK FOR SUPERCELL TORNADOES AND LARGE HAIL...A TORNADO
RISK COULD CONTINUE WITH THE TRANSITION TO A QUASI-LINEAR
MODE...ESPECIALLY PREFERENTIALLY ON THE SOUTHERN MOST CELLS
AS THEY DEVELOP ALONG THE FRONT. THE SEVERE RISK SHOULD
DIMINISH ON SUNDAY NIGHT AND HOPEFULLY MUCH OF CENTRAL AND
SOUTH CENTRAL KANSAS WILL EXPERIENCE MORE NUMEROUS COVERAGE
OF CONVECTION FOR MUCH NEEDED RAINFALL.

 

DMX:

ALL EYES ARE ON SUNDAY WHEN THERE IS A LIKELIHOOD OF SEVERE
WEATHER ACROSS MUCH OF THE FORECAST AREA. THIS POTENTIAL IS WELL
COVERED IN THE SPC OUTLOOK DISCUSSION AND READERS ARE ENCOURAGED
TO UTILIZE THAT RESOURCE AS IT IS UPDATED THROUGH TONIGHT AND INTO
TOMORROW. IN SHORT...BY SUNDAY MORNING AN ELONGATED SURFACE LOW
PRESSURE SYSTEM WILL STRETCH FROM AROUND THE OKLAHOMA PANHANDLE
NORTHEAST TOWARD IOWA WITH AN INVERTED TROUGH ALONG ITS AXIS.
ONGOING STORMS AROUND EASTERN NEBRASKA AND ALONG THE
IOWA/MISSOURI BORDER WILL COMPLICATE THE SITUATION...AND LIKELY
RESULT IN AN EFFECTIVE WARM FRONT STRETCHING ACROSS CENTRAL IOWA
BY SUNDAY AFTERNOON...CONNECTING TO A COLD FRONT RUNNING DOWN INTO
CENTRAL OR EASTERN KANSAS. SEVERE THUNDERSTORM POTENTIAL WILL BE
MAXIMIZED ALONG THIS EFFECTIVE WARM FRONT WITH VERY HIGH
INSTABILITY AND WIND SHEAR SUPPORTING SUPERCELLS AND POSSIBLY
MULTIPLE...STRONG TORNADOES. HOWEVER...THE DETAILS OF WHERE THIS
WARM FRONT LIES AND EXACTLY HOW MUCH DESTABILIZATION WILL OCCUR
WILL BE DEPENDENT ON THE EVOLUTION OF THE OVERNIGHT/MORNING STORMS
AND THUS THE THREAT IS SOMEWHAT CONDITIONAL. ALL RESIDENTS OF IOWA
SHOULD BE ON ALERT AND MONITOR THE LATEST WEATHER INFORMATION
CLOSELY TONIGHT AND SUNDAY INTO SUNDAY NIGHT.

[JoMo]

It's really surprising how bad some of the radar holes are and how long they've let them go without working towards a resolution.

 

They could plug the Plains holes with probably 7-8 radars.

 

[Superstorm93]

If we get something like what is happening today over IA and MO tomorrow, there will be some serious problems to say the least.

 

Also TOP has a much stronger worded (and very well written) discussion with their most recent AFD.

 

OAX:

 

ICT:

 

DMX:

 

Impressive amount of discrete cells...

 

[Indystorm]

 

BULLETIN - IMMEDIATE BROADCAST REQUESTED  

SEVERE THUNDERSTORM WARNING  

NATIONAL WEATHER SERVICE TOPEKA KS  

443 PM CDT SAT MAY 10 2014  

 

THE NATIONAL WEATHER SERVICE IN TOPEKA HAS ISSUED A  

 

* SEVERE THUNDERSTORM WARNING FOR...  

CENTRAL LYON COUNTY IN EAST CENTRAL KANSAS...  

 

* UNTIL 530 PM CDT  

 

* AT 441 PM CDT...A SEVERE THUNDERSTORM WAS LOCATED 8 MILES SOUTHEAST  

OF COTTONWOOD FALLS...AND MOVING NORTHEAST AT 40 MPH.  

 

HAZARD...HEN EGG SIZE HAIL AND 70 MPH WIND GUSTS.  

 

SOURCE...RADAR INDICATED.  

 

IMPACT...PEOPLE AND ANIMALS OUTDOORS WILL BE INJURED. EXPECT HAIL  

DAMAGE TO ROOFS...SIDING...WINDOWS AND VEHICLES. EXPECT  

CONSIDERABLE TREE DAMAGE. WIND DAMAGE IS ALSO LIKELY TO  

MOBILE HOMES...ROOFS AND OUTBUILDINGS.  

 

* THE SEVERE THUNDERSTORM WILL BE NEAR...  

EMPORIA AROUND 505 PM CDT.  

AMERICUS AROUND 510 PM CDT.  

ADMIRE AND ALLEN AROUND 525 PM CDT.  

[Hvward]

KMBC on live with the chopper cam near KC.  http://www.kmbc.com/news/live/24440840

[Indystorm]

Cell nw of Trenton MO looks like a beast of a hailer.