Significant severe weather threats 4/8-10

[Ian]

Cell near La Crosse looks nice.. dropping decent hail. Pretty high based looking at cams tho. Might have a chance. Almost right where our supercell was last yr.

[thunderman]

Cell near La Crosse looks nice.. dropping decent hail. Pretty high based looking at cams tho. Might have a chance. Almost right where our supercell was last yr.

 

I doubt it does much tornado wise ... better moisture is still a bit to far south.  However I would for that cell potential drop some monster hail.

[iowahawkeyedave]

I doubt it does much tornado wise ... better moisture is still a bit to far south.  However I would for that cell potential drop some monster hail.

Yeah, it might have a better chance if it keeps making that right turn and heads towards Great Bend.

[ND_Supercell]

What did they change?

 

Yikes! I hadn't dusted this product off in months until today, but they did change the formula and it is definitely generating much higher probabilities now. That's a shame because my very anecdotal evidence was that it was well-calibrated with a low false alarm rate.

 

They must have felt it didn't have a very high probability of detection, though, because they relaxed the criteria for MLCAPE (now >500, previously > 1000 J/kg) and more importantly, MLLCL (now <1500 m AGL, previously < 1000 m AGL). The 60 to 75 % probabilities over north central OK and south central KS early this evening based on today's 15Z SREF run seemed relatively rare using the old formula.

[soonertrey]

We would have gone nuts for a significant tornado ingredients map like this last year--- that is, before they changed the formula for it.  It's for today (3 hours in the future)  ha ha.

 

http://www.americanwx.com/bb/index.php?app=core&module=attach&section=attach&attach_rel_module=post&attach_id=95930'>SREF_prob_combined_sigtor__f015.gif

That is an absolute joke.

[Indystorm]

Not expecting much in the way of tornadoes this evening but thinking we could see some sig hail. 60-64 dews are creeping northward into central OK now and will help prime the pump for tomorrow and Tuesday.

[Chicago Storm]

There was a weak/disorganized wall cloud on the cell near Bison, KS for a time.

[Buckeye05]

I have seen multiple brief cone funnels on Ben McMillans cam...

[Chicago Storm]

I have seen multiple brief cone funnels on Ben McMillans cam...

Yep...It tried but failed once again.

[thunderman]

Storm in western MO means serious business.  Damaging winds and hail up to 2" very likely.

 

[Indystorm]

If we can get a lone supercell like the one currently over sw MO with all the right parameters tomorrow or Tuesday we could really have a beast of a tornado producing storm.

[harrisale]

Nice sounding for Woodward, OK tomorrow off the 00Z NAM, although surface temp-dewpoint spread is a little far and thus LCL could be a limiting factor (1493m).

[Ian]

Things still seem a bit slow for tomorrow overall... if it was like late May or June maybe. Could be something good tho I guess.. jet over the warm sector isn't fantastic. I'd prob push into eastern CO and hope for the best.

[Chinook]

For what it's worth-- this is a radar anomaly. (Central Nebraska) How does such a thing happen?  It looks like a thunderstorm, but it isn't. The high reflectivity was only at the 0.5 degree tilt.

 

 

[JoMo]

For what it's worth-- this is a radar anomaly. (Central Nebraska) How does such a thing happen?  It looks like a thunderstorm, but it isn't. The high reflectivity was only at the 0.5 degree tilt.

 

 

2013_04_08_0418z_radar_anomaly.png

 

HAARP!! (kidding)

 

It looks like anomalous propagation. Perhaps superrefraction/ducting based on the strength of the echoes. 

[JoMo]

Things still seem a bit slow for tomorrow overall... if it was like late May or June maybe. Could be something good tho I guess.. jet over the warm sector isn't fantastic. I'd prob push into eastern CO and hope for the best.

 

E CO and NW KS looks like the place to be.

 

[JoMo]

Day 2 is out. Score one for the ECMWF and Tulsa AFD this afternoon and yesterday noticing the increasing anafrontal tendencies. 

 

 

 

 

DAY 2 CONVECTIVE OUTLOOK   NWS STORM PREDICTION CENTER NORMAN OK  1253 AM CDT MON APR 08 2013     VALID 091200Z - 101200Z     ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE LOWER MO VALLEY TO THE  SRN PLAINS...      ..SYNOPSIS    HIGHLY AMPLIFIED UPPER-LEVEL TROUGH OVER THE WEST SHOULD EVOLVE INTO  A FEW DISTINCT SHORTWAVE IMPULSES...TWO OF WHICH WILL BE PROMINENT  FOR AFFECTING SEVERE POTENTIAL IN THE CNTRL STATES. ONE IMPULSE  SHOULD MOVE NEWD TOWARDS THE CNTRL HIGH PLAINS/BLACK HILLS...WHILE  ANOTHER SHOULD EJECT ONTO THE SRN HIGH PLAINS TUE NIGHT. AT THE  SURFACE...A DRYLINE WILL MIX EWD INTO WRN OK AND ACROSS THE EDWARDS  PLATEAU IN TX. A SHARP COLD FRONT WILL PROGRESSIVELY OVERTAKE THE  DRYLINE...LIKELY REACHING A NERN TO S-CNTRL TX LINE BY 12Z/WED.         ..LOWER MO VALLEY TO THE SRN PLAINS    A BROAD CORRIDOR OF SEVERE TSTMS WITH ALL HAZARD TYPES POSSIBLE IS  EXPECTED TO COMMENCE TUE AFTERNOON AND CONTINUE THROUGH WED MORNING.     NCEP GUIDANCE HAS FINALLY COME INTO LINE WITH THE MORE CONSISTENT  ECMWF WITH DETAILS OVER THE SYNOPTIC PATTERN...RENDERING HIGHER  CONFIDENCE IN THE ANTICIPATED CONVECTIVE EVOLUTION. NEVERTHELESS...A  FEW LIMITING FACTORS HAVE MITIGATED A MODERATE RISK ISSUANCE ATTM. A  MODERATELY UNSTABLE AIR MASS WILL BECOME MORE WIDESPREAD WITH LOWER  TO MIDDLE 60S SURFACE DEW POINTS IN MOST OF THE S-CNTRL  CONUS...BENEATH A STOUT CAPPING INVERSION THAT SHOULD LARGELY  INHIBIT WARM SECTOR/DRYLINE TSTM DEVELOPMENT. SHORTWAVE IMPULSES  EJECTING FROM THE WRN CONUS TROUGH ALSO DO NOT APPEAR FAVORABLY  TIMED FOR THE DIURNAL HEATING CYCLE...WITH GREATER MID-LEVEL HEIGHT  FALLS NOT ANTICIPATED TO OVERSPREAD THE WARM SECTOR UNTIL THE LATTER  HALF OF THE PERIOD. DAYTIME TSTM INITIATION WILL LIKELY BE TIED TO  THE COLD FRONT AND NEAR THE INTERSECTION OF THE MERGING COLD  FRONT/DRYLINE...WITH TSTM COVERAGE SUBSTANTIALLY INCREASING DURING  THE EVENING/OVERNIGHT. THE UNDERCUTTING NATURE OF THE COLD FRONT  SHOULD LIMIT THE SUSTAINABILITY OF ROBUST INDIVIDUAL UPDRAFTS.    NEVERTHELESS...STEEP MID-LEVEL LAPSE RATES AND STRONG DEEP-LAYER  SHEAR WILL BE FAVORABLE FOR SUPERCELL CLUSTERS INITIALLY PRODUCING  LARGE HAIL /SOME SIGNIFICANT/ ALONG WITH A FEW TORNADOES AND  ISOLATED DAMAGING WINDS. WITH TIME...AN EXTENSIVE LINE OF CONVECTION  SHOULD FORM BUT AS THE COLD FRONT BECOMES INCREASINGLY  ANAFRONTAL...SEVERE HAIL/WIND RISKS MAY BE SUBDUED. STILL...SOME  INCREASE IN TORNADO AND DAMAGING WIND THREAT IS POSSIBLE EARLY WED  MAINLY IN NERN TX/WRN AR AS LOW-LEVEL SLYS STRENGTHEN WITH APPROACH  OF THE SRN HIGH PLAINS IMPULSE.  

 

 

This is from Tulsa's AFD Sunday Afternoon:

 

 

THE MOST LIKELY SCENARIO IS FRONTAL FORCING ALONG A SURGING COLD FRONTWILL PROVIDE THE LIFT NEEDED FOR CONVECTION. HOWEVER...SINCE UPPERTROUGH IS COMING OUT WITH A POSITIVE TILT...THE UPPER FLOW WILL BEPARALLEL TO THE FRONT...THUS STORMS THAT DEVELOP WITH THE FRONTWILL TEND TO BE UNDERCUT QUICKLY. THE ECMWF CONTINUES TO SHOWALMOST ALL QPF ON THE COOL SIDE OF THE FRONT...INDICATIVE OF THISVERY SCENARIO. I`M NOT SAYING THERE WILL NOT BE SEVEREWEATHER...BUT THE TENDENCY FOR STORMS TO BE UNDERCUT WILL LIMITTHE SEVERE POTENTIAL. POST-FRONTAL RAIN AND STORMS ARE FORECAST TOCONTINUE THRU WEDNESDAY...TAPERING OFF BY THURSDAY MORNING.

[thunderman]

NSSL WRF for this afternoon.  Develops a line across western KS.  Biggest "interest" cell is one on the southern end that seems to be able to organize pretty well.

 

00z Z:

 

04z Z:

 

03z Max Updraft Helicity:

[Ian]

E CO and NW KS looks like the place to be.

 

 

prob i40 either side of the border or maybe the alva to pratt corridor tho that one seems it's a big gamble still.. not sure the cap goes. kinda wonder if they really need a 10% but whatever.

[SluggerWx]

Sun is coming out here in Denver. Blue skies closer to the foothills, and the haze is fading at my house in Stapleton.

[BryanB]

Day 2 of the Plains Tornado Chase has brought us to Colby, Kansas. Currently sitting at 68° and mostly sunny. Will take a wait and see approach before moving, but hopefully can get a nice cell to develop out in E. Colorado and move out into Kansas.

[JoMo]

The new Day 2 gave me a headache.

 

http://www.spc.noaa.gov/products/outlook/day2otlk.html

[Jim Marusak]

any plans to put up an 18Z-20Z sonde in LBF, DDC, or AMA to see how much of a cap they'll have to overcome with the air mass? because that seems to be the uncertainty attm, not whether the potential is there once the cap breaks.

[baroclinic_instability]

any plans to put up an 18Z-20Z sonde in LBF, DDC, or AMA to see how much of a cap they'll have to overcome with the air mass? because that seems to be the uncertainty attm, not whether the potential is there once the cap breaks.

I would guess no for this event, especially with the budget crunch.

[Jim Marusak]

I would guess no for this event, especially with the budget crunch.

just wondering.

 

but with the budget crunch, will this curtail any such efforts if we get indications of a real big outbreak, or even for major hurricanes down the line?

[SluggerWx]

In Denver now, thinking of heading east about 200 miles in an hour or so.

Think it'll be worth the haul?

3 hours of driving is a rather low opportunity cost to at least see awesome structure on the plains.

Thoughts?

Sent from my DROID RAZR using Tapatalk 2

[harrisale]

any plans to put up an 18Z-20Z sonde in LBF, DDC, or AMA to see how much of a cap they'll have to overcome with the air mass? because that seems to be the uncertainty attm, not whether the potential is there once the cap breaks.

 

Cap definitely the issue today. SPC Tornado probs dropped to 5% now.

[ZackH]

In Denver now, thinking of heading east about 200 miles in an hour or so. Think it'll be worth the haul? 3 hours of driving is a rather low opportunity cost to at least see awesome structure on the plains. Thoughts? Sent from my DROID RAZR using Tapatalk 2

 

If you can get to the Colby, KS area, you will most likely see storms/supercells.  There should also be a window to see a tornado or two as well before the storms run into the stout eastern CAP.  The further south target is the higher risk, higher reward play IMO.  If it goes, the storms will be much more impressive further south near the OK/KS border.  However, I think that you will see nice structure in NW KS and maybe a tornado.

[icebreaker5221]

15Z HRRR breaks the cap and develops a lone supercell in east-central CO that tracks into northwest KS later in the evening.  Definitely an improvement over earlier runs of the HRRR which had little to nothing. 

[andyhb]

15Z HRRR breaks the cap and develops a lone supercell in east-central CO that tracks into northwest KS later in the evening.  Definitely an improvement over earlier runs of the HRRR which had little to nothing. 

 

This appears to be in agreement with the SPC/NSSL WRF, which have one or two supercells in the same general area.