May 15th - 20th Plains Storm/Severe disco

[Stebo]

Thinking we can put more confidence in the GFS at this point?

 

I wouldn't say more confidence in the GFS, however I would say much less confidence in the NAM.

[Thundersnow12]

Getting lunch in Hays then heading south to probably DDC or Greensburg. 

[SquatchinNY]

OK is pumping parameters.

CAPE: 3000-5000

LI: -8 to -12

EHI 3 km: 2-6

Currently, that is

[KSWx]

Welp, looks like the preliminary 12Z GFS is coming into agreement with the 12Z NAM.

 

Edit: Scratch that, 00Z is looking good as ever.

[Stebo]

Welp, looks like the preliminary 12Z GFS is coming into agreement with the 12Z NAM.

Looks unchanged from the previous runs with respect to tomorrow maybe a touch east with the main instability axis but nothing terribly significant.

[David Reimer]

Dodge City and Wichita will be holding conference calls this afternoon as the "Severe weather threat has increased across the area this evening."

[Indystorm]

 

Maybe up in your area, but things are turning bad (more tornadic) down here. Especially around 00z-03z. 

 

Stay safe and monitor events for us.  I know you will be on your guard and especially watchful this weekend into Monday.

[Ground Scouring]

For today's event, the 12Z RAP is not showing as much 0-1-km helicity as it did on previous runs...due primarily to a weaker surface low by 00Z tonight. This results in less low-level backing relative to the LLJ which takes a somewhat longer time to intensify overnight. So the best kinematics and the best thermodynamics are not exactly aligned. With the capping in place, this could cut down the tornado risk. My main focus is shifting to tomorrow, which based upon trends is looking like a High Risk, especially with the trend toward a secondary surface low which would boost the tornado threat between 00-06Z. The overnight LLJ and helicity look formidable.

[Superstorm93]

Current SBCAPE and DEWPS 

 

 

(Not for the faint of bandwidth)

 

http://i300.photobucket.com/albums/nn39/Stormchaser20079/American%20Stuff/ScreenHunter_21May181150.png

 

Parts of Oklahoma are already popping 7000+ j/KG 

 

 

 

[Thundersnow12]

Not because of this parameter alone but I would think tomorrow will go high risk at some point. When was the last day we had 2 days like this in a row in the plains? 

 

[ZackH]

For today's event, the 12Z RAP is not showing as much 0-1-km helicity as it did on previous runs...due primarily to a weaker surface low by 00Z tonight. This results in less low-level backing relative to the LLJ which takes a somewhat longer time to intensify overnight. So the best kinematics and the best thermodynamics are not exactly aligned. With the capping in place, this could cut down the tornado risk. My main focus is shifting to tomorrow, which based upon trends is looking like a High Risk, especially with the trend toward a secondary surface low which would boost the tornado threat between 00-06Z. The overnight LLJ and helicity look formidable.

 

Yah, but the RAP has shown to be fairly useless... and it was also showing very unrealistic moisture issues on earlier runs... I don't trust it.

[baroclinic_instability]

Near Norman Monday, in the vicinity of the secondary lee low. 

[brettjrob]

Between the unfavorable frontal/dryline orientation (SW-NE) and questionable backing of low-level winds, I'm not even convinced tomorrow warrants a 15% hatched tor area, let alone HIGH, at this stage. Those different biases and perspectives we all have that baro mentioned yesterday are a funny thing. But I'm focused mainly on today, which I think will impress barring too much mixing (which remains a possibility).

[baroclinic_instability]

DAY 3 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
0231 AM CDT SAT MAY 18 2013

VALID 201200Z - 211200Z

...THERE IS A SLGT RISK OF SVR TSTMS ACROSS PARTS OF THE SRN
PLAINS...CNTRL PLAINS...MID MS VALLEY...UPPER MS VALLEY AND GREAT
LAKES REGION...

...REGIONAL SEVERE WEATHER EPISODE POSSIBLE ACROSS PARTS OF THE SRN
AND CNTRL PLAINS INTO THE OZARKS MONDAY AFTERNOON AND EVENING...

...SRN AND CNTRL PLAINS/OZARK PLATEAU...
AN UPPER-LEVEL LOW WILL REMAIN IN PLACE ACROSS THE NRN AND CNTRL
PLAINS ON MONDAY WITH SOUTHWEST FLOW LOCATED FROM THE SRN PLAINS
INTO THE MID MS VALLEY. AT THE SFC...A LOW IS FORECAST TO MOVE NEWD
ACROSS THE SRN PLAINS WITH DEWPOINTS SOUTH AND EAST OF THE LOW IN
THE MID TO UPPER 60S F. A CAPPING INVERSION IN PLACE FOR MUCH OF THE
DAY...SHOULD WEAKEN BY LATE AFTERNOON ALLOWING FOR ROBUST CONVECTIVE
INITIATION. MODEL FORECASTS DEVELOP SEVERAL CLUSTERS OF
THUNDERSTORMS LATE MONDAY AFTERNOON FROM THE SFC LOW NEAR THE RED
RIVER NEWD INTO CNTRL AND ERN OK. THE MODELS APPEAR TO ORGANIZE AN
MCS ACROSS THE SRN PLAINS AND MOVE THIS CONVECTIVE SYSTEM NEWD INTO
THE OZARKS DURING THE EVENING.

FORECAST SOUNDINGS IN SRN OK AND NEAR THE RED RIVER IN NORTH TX AT
00Z/TUE SHOW IMPRESSIVE THERMODYNAMIC AND SHEAR PROFILES WITH MLCAPE
VALUES OF 2500 TO 3500 J/KG AND 0-6 KM SHEAR VALUES OF 45 TO 55 KT.
THIS ENVIRONMENT SHOULD BE FAVORABLE FOR SUPERCELLS WITH LARGE HAIL.
HAILSTONES OF GREATER THAN 2 INCHES IN DIAMETER WILL BE POSSIBLE
WITH THE MORE DOMINANT SUPERCELLS. IN ADDITION...LOW-LEVEL
HODOGRAPHS ALSO LOOK IMPRESSIVE WITH 0-3 KM STORM RELATIVE
HELICITIES IN THE 400 TO 50O M2/S2 RANGE BY EARLY MONDAY EVENING.
THIS SUGGESTS TORNADIC SUPERCELLS WILL BE POSSIBLE WITH A POTENTIAL
FOR STRONG TORNADOES. IF MESOSCALE CONDITIONS COME TOGETHER AS THE
MODELS SUGGEST...THEN A CLUSTER OF TORNADOES COULD OCCUR ACROSS
PARTS OF THE SRN PLAINS LATE MONDAY AFTERNOON INTO THE EVENING. WIND
DAMAGE WILL ALSO BE POSSIBLE WITH SUPERCELLS AND BOWING
LINE-SEGMENTS. THE MAIN CONCERN ABOUT FORECASTING A SIGNIFICANT
EVENT THIS FAR OUT...IS THAT MULTIPLE DAYS OF THUNDERSTORMS BETWEEN
NOW AND MONDAY WILL LIKELY ALTER THE OUTCOME AND THAT THE SCENARIO
WILL BE DIFFERENT THAN WHAT IS CURRENTLY PRESENTED BY THE MODELS.

...MID TO UPPER MS VALLEY/GREAT LAKES...
AN UPPER-LEVEL LOW IS FORECAST TO REMAIN IN PLACE ACROSS THE NRN AND
CNTRL PLAINS ON MONDAY AS A SHORTWAVE TROUGH ROTATES AROUND THE ERN
SIDE OF THE UPPER-LEVEL LOW. THE SHORTWAVE TROUGH AND AN ASSOCIATED
MID-LEVEL JET WILL HELP FOCUS CONVECTIVE DEVELOPMENT ACROSS THE MID
TO UPPER MS VALLEY AND GREAT LAKES REGION MONDAY AFTERNOON. SFC
DEWPOINTS ARE FORECAST TO BE IN THE LOWER TO MID 60S F ACROSS A
BROAD CORRIDOR FROM THE MID MS VALLEY EXTENDING NEWD INTO THE LOWER
OH VALLEY WHERE THE MODELS DEVELOP MODERATE INSTABILITY BY
AFTERNOON. THIS COMBINED WITH MODERATE DEEP LAYER SHEAR
PROFILES...ENHANCED BY THE MID-LEVEL JET...SHOULD SUPPORT SEVERE
THUNDERSTORM DEVELOPMENT. THE SEVERE THREAT SHOULD DEVELOP ACROSS A
BROAD AREA WHERE MESOSCALE FEATURES AND THE MAGNITUDE OF INSTABILITY
WILL BECOME IMPORTANT FOR SEVERE THREAT COVERAGE. WIND DAMAGE AND
LARGE HAIL APPEAR TO BE THE GREATEST THREATS AT THIS TIME BUT MUCH
UNCERTAINTY EXISTS CONCERNING HOW THE EVENT WILL PLAY OUT.

..BROYLES.. 05/18/2013

[Superstorm93]

Not even lunch and the roads are already loaded with spotters. 

 

[Stebo]

Not even lunch and the roads are already loaded with spotters. 

 

ScreenHunter_21 May. 18 12.04.png

 

Damn and this is just the known ones, not counting your average Joes.

[Ground Scouring]

12Z GFS for 00Z tonight on the OK-KS border, east of U.S. Route 183:

 

 

[baroclinic_instability]

Not trying to derail today, but the latest 12z GFS is undoubtedly the most impressive run I have seen from any of the globals for Monday, parking a sub 1000 hpa lee low near the Panhandle late Monday. Both the 12z NAM/GFS are cranking the 850 flow into the 55 kt range by 03z Monday as the dynamic/nocturnal LLJ gets going. 

[baroclinic_instability]

Weenie-land for hires modeling, but the last frame of the NAM 4 km (60 hr) for 00z Tuesday (Mon evening) across OK.

[Superstorm93]

Extremely impressive WRF-NMM gif. Sunday looks like a skilled weenie drew that scenario. 

 

(Courtesy of Dr. Ryan Maue) 

 

[CT Rain]

Nice looking sounding this morning at DDC. Obviously a lot of CIN to overcome but with falling heights and QG forcing over the area we should see that cap erode nicely this afternoon. 

 

 

[yoda]

1630 SPC OTLK

 

..CENTRAL PLAINS    AN INITIAL IMPULSE...NOW LIFTING NORTHEAST OF THE PANHANDLE REGION  INTO THE CENTRAL PLAINS...IS CONTRIBUTING TO SOME UNCERTAINTY  CONCERNING DRYLINE POSITION AND CONVECTIVE POTENTIAL LATER THIS  AFTERNOON...MAINLY SOUTH OF THE KANSAS/OKLAHOMA BORDER.  HOWEVER...THE DRYLINE IS STILL EXPECTED TO BE THE MAIN FOCUS FOR  STRONGEST DESTABILIZATION AND STORM DEVELOPMENT LATER THIS  AFTERNOON.  AIDED BY FORCING ASSOCIATED WITH CONTINUING MID-LEVEL  HEIGHT FALLS...SUBSTANTIAL MID-LEVEL INHIBITION IS EXPECTED TO  WEAKEN SUFFICIENTLY FOR THE INITIATION OF DISCRETE SUPERCELLS ACROSS  SOUTHWESTERN NEBRASKA INTO WESTERN KANSAS DURING THE 21-00Z TIME  FRAME...PERHAPS SOUTHWARD ACROSS WESTERN OKLAHOMA INTO NORTHWEST  TEXAS AS WELL.    VERY LARGE HAIL MAY BE THE PRIMARY SEVERE THREAT...INITIALLY... BUT  LOW-LEVEL LAPSE RATES PROBABLY WILL BE SUFFICIENTLY STEEP TO SUPPORT  A RISK FOR TORNADOES BENEATH INCREASINGLY CYCLONIC AND DIFLUENT  HIGH-LEVEL FLOW.  AS THE 850 MB JET BECOMES MORE SOUTHERLY AND  STRENGTHENS TO 40-50+ KT LATER THIS EVENING...A WINDOW OF  OPPORTUNITY WILL EXIST FOR INCREASING TORNADIC POTENTIAL...INCLUDING  THE RISK FOR ONE OR TWO STRONG TORNADOES.  THIS POTENTIAL APPEARS TO  HINGE LARGELY ON HOW LONG IT TAKES FOR CONVECTION TO GROW UPSCALE  INTO ORGANIZING MESOSCALE CONVECTIVE SYSTEMS...WITH DAMAGING  STRAIGHT LINE WINDS BECOMING A MORE PROMINENT THREAT.  THIS REMAINS  UNCERTAIN...BUT IT APPEARS THAT UPSCALE GROWTH COULD OCCUR FAIRLY  QUICKLY.    ..KERR/DEAN.. 05/18/2013  

[baroclinic_instability]

Nice looking sounding this morning at DDC. Obviously a lot of CIN to overcome but with falling heights and QG forcing over the area we should see that cap erode nicely this afternoon. 

That sounding verbatim would take a lot more than synoptic QG forcing (even in the presence of strong diurnal heating) to erode that cap.

[CT Rain]

That sounding verbatim would take a lot more than synoptic QG forcing (even in the presence of strong diurnal heating) to erode that cap.

 

Some more low level moisture wouldn't hurt lol

[Chicago Storm]

We just passed through ICT, heading west.

[Ian]

Between the unfavorable frontal/dryline orientation (SW-NE) and questionable backing of low-level winds, I'm not even convinced tomorrow warrants a 15% hatched tor area, let alone HIGH, at this stage. Those different biases and perspectives we all have that baro mentioned yesterday are a funny thing. But I'm focused mainly on today, which I think will impress barring too much mixing (which remains a possibility).

Where you going?

[Thundersnow12]

We just passed through ICT, heading west.

 

In Hays now, then south.

[JoMo]

Tulsa for Sunday. (big graphic)

 

http://www.srh.noaa.gov/images/rtimages/tsa/headimg.png

[David Reimer]

For those chasing today, gas is at $3.79 at the Cenex in Greensburg. That's pretty much lower than what I saw anywhere else on 400 between here and Wichita. We're still chilling at the Best Western on the west side of town. Skies are pretty much clear now in the low levels. 

[Ian]

We're in Russell but have mainly just been heading west thru now. Dropping south a bit, probably to Great Bend for a bit. Not sure which target to bite on but tempted to do the southern KS one.