May 11, 2014

Post date: May 11, 2014 2:15:51 PM

Sunday, May 11, 2014 @ 0910 CDT: It was a long -- but very exciting -- chase day, including tracking a group of cells near Kansas City for over four hours. We *did* experience a tornado east of KC, but instead of getting photogenic shots of it, we were trying our best to make sure we didn't get in its way! Rain-wrapped and almost impossible to see, we caught a hard edge of it as it got close to us while we were trying to negotiate some iffy roads in the area. [Nearest village: Arrow Rock, MO.] It was close enough for us to hear the distinctive "roar" of the storm, and we verified that others had reported a tornado on the ground in the same vicinity. I will see if any of my crappy GoPro video shows the hard edge, and will post that later if it turns out well.

Anyway, here are the shots that I *did* get.

As for today, it's still a MODERATE RISK day, and things look promising for possible tornadoes. It looks like we will need to move to our northwest, though, so I will update you all whenever I get a better idea of what the plan is.

...and here's yesterday's travel map:

Sunday, May 11, 2014 @ 1100 CDT: After a quick breakfast at McDonald's (ugh!), we're on the road again, initially targeting the Nebraska City area. I am looking forward to seeing the SPC update later...

Sunday, May 11, 2014 @ 1115 CDT: Here's the SPC text relative to today's MODERATE RISK setup:

SPC AC 111259

DAY 1 CONVECTIVE OUTLOOK

NWS STORM PREDICTION CENTER NORMAN OK

0759 AM CDT SUN MAY 11 2014

VALID 111300Z - 121200Z

...THERE IS A MDT RISK OF SVR TSTMS OVER PARTS OF THE CNTRL PLNS AND MID-MS VLY...

...THERE IS A SLGT RISK OF SVR TSTMS SURROUNDING THE MDT RISK REGION...FROM SW TX NEWD INTO THE OH VLY/GRT LKS...

...SUMMARY...

SEVERE THUNDERSTORMS ARE EXPECTED TO DEVELOP FROM PARTS OF THE CENTRAL PLAINS THROUGH THE MID-MISSISSIPPI VALLEY INTO THE OHIO VALLEY TODAY THROUGH TONIGHT. THE GREATEST CONCENTRATION OF SEVERE WEATHER SHOULD EXTEND FROM CENTRAL AND NORTHERN KANSAS THROUGH SOUTHEAST NEBRASKA INTO MUCH OF IOWA. VERY LARGE HAIL...DAMAGING WIND...AND TORNADOES WILL OCCUR.

...SYNOPTIC SETUP...

POTENT NV/UT UPR LOW/TROUGH SHOULD MOVE E TO THE UT/CO BORDER AREA THIS EVE...BEFORE TURNING ENE AND DEAMPLIFYING OVER ERN CO EARLY MON. THIS WILL RESULT IN STRENGTHENING SSW FLOW OVER THE CNTRL AND SRN PLNS THROUGH THE PERIOD AS HEIGHTS CONTINUE TO RISE OVER THE OH VLY/GRT LKS.

AT LWR LVLS...ELONGATED LOW PRESSURE NOW IN PLACE FROM THE TX PANHANDLE NE INTO ERN NEB/WRN IA EXPECTED TO REMAIN NEARLY STNRY TODAY AS CIRCULATION CENTER DIURNALLY STRENGTHENS OVER THE OK PANHANDLE. THE LOW SHOULD ADVANCE E/NEWD TNGT AND EARLY MON AS SHORTWAVE IMPULSE NOW NEAR THE FOUR CORNERS CONTINUES E INTO THE SRN HIGH PLNS.

THE COLD/STNRY FRONT ASSOCIATED WITH THE PLNS LOW...AND...TO SOME EXTENT...OUTFLOW BOUNDARIES/DIFFUSE WARM FRONT EXTENDING EWD INTO SE NEB/IA...WILL BE THE MAIN FOCUS FOR SVR TSTMS TODAY THROUGH TNGT. CONDITIONS WILL BE FAVORABLE FOR LARGE HAIL...VERY STRONG WINDS...AND A FEW TORNADOES.

..CNTRL PLNS/MID MS VLY TODAY/TNGT...

SATELLITE AND MODEL FCSTS AGREE THAT WEAK HEIGHT RISES WILL PREVAIL OVER FAR ERN PORTIONS OF THE PLNS AND THE MID-MS VLY TODAY DOWNSTREAM FROM GRT BASIN TROUGH. THIS SUGGESTS THAT SFC HEATING AND LOW-LVL WAA/MOISTURE TRANSPORT WILL BE THE MAIN DESTABILIZATION MECHANISMS OVER THE REGION. THIS SHOULD ALLOW STORMS/MCS NOW OVER SE NEB TO MOVE/DEVELOP ESE ALONG DIFFUSE WARM FRONT ACROSS SRN IA TODAY. OTHER STORMS MAY FORM WITH SFC HEATING FARTHER E/SE INTO PARTS OF IL/IND.

WHILE WIND PROFILES ACROSS THIS REGION WILL SUPPORT SUPERCELLS...ESPECIALLY WITH WWD EXTENT...THE PREDOMINANT STORM MODE WILL BE COMPLICATED BY PRESENCE OF OUTFLOW BOUNDARIES / WEAK FRONTAL SEGMENTS. IF DISCRETE STORMS DO FORM...SETUP COULD SUPPORT A COUPLE TORNADOES IN ADDITION TO LARGE HAIL/LOCALLY DMGG WIND GIVEN RICH LOW-LVL MOISTURE /SFC DEWPOINTS IN THE MID 60S F/ SPREADING NWD FROM CNTRL MO.

FARTHER W...GIVEN STOUT EML CAP...EXPECT THAT MOST OF THE CNTRL PLNS E AND S OF AFOREMENTIONED COLD/STNRY FRONT WILL REMAIN STORM-FREE THROUGH MID-AFTN. BUT COMBINATION OF STRONG SFC HEATING WITH FRONTAL UPLIFT SHOULD SUPPORT VIGOROUS CONVECTIVE DEVELOPMENT ALONG THE BOUNDARY AROUND 21Z FROM SE NEB SSW INTO SW KS. SOME OF THE ACTIVITY IN CNTRL/SW KS INITIALLY WILL BE RELATIVELY HIGH-BASED. COUPLED WITH STRENGTHENING DEEP WIND FIELD /700 MB SPEEDS AROUND 50 KTS ORIENTED ROUGHLY PARALLEL TO THE FRONT/...SETUP COULD SUPPORT UPSCALE DEVELOPMENT INTO AN MCS WITH BOWING SEGMENTS. THESE WILL POSE A RISK FOR SWATHS OF HIGH WIND...IN ADDITION TO LARGE HAIL AND A TORNADO OR TWO. THESE STORMS SHOULD FURTHER CONSOLIDATE OVER CNTRL AND NRN KS THIS EVE/EARLY TNGT AS TROUGH APPROACHES REGION...FURTHER ENHANCING WIND FIELD/ASCENT. EMBEDDED LEWPS/BOWS IN THE MCS WILL POSE A CONTINUING RISK FOR SVR WIND AND ISOLD TORNADOES THROUGH EARLY MON NEWD INTO MUCH OF IA.

FARTHER NE IN NRN KS AND SE NEB/WRN IA...ENVIRONMENT OF 3000 J/KG SBCAPE WITH SMALLER TEMPERATURE-DEW POINT SPREADS AND STRONG SHEAR COULD YIELD A SIZABLE TORNADO THREAT...IN ADDITION TO SVR HAIL AND WIND. THIS THREAT WOULD BE GREATEST WITH ANY STORMS THAT ARE ABLE TO REMAIN SEMI-DISCRETE AND/OR MOVE ALONG OUTFLOW BOUNDARY SEGMENTS LEFT FROM MORNING STORMS.

FARTHER S...ISOLD SVR STORMS MAY FORM WITH AFTN HEATING ALONG DRY LINE/LEE TROUGH EXTENDING SSW THROUGH FAR WRN OK INTO NW TX. LOCALLY DMGG WIND AND HAIL SHOULD BE THE MAIN RISKS POSED BY THIS GENERALLY HIGHER-BASED ACTIVITY. ADDITIONAL STORMS MAY FORM IN THE REGION LATE TNGT OR...MORE LIKELY...EARLY MON AS STRONGER HEIGHT FALLS OVERSPREAD REGION.

..CORFIDI/SMITH.. 05/11/2014

Sunday, May 11, 2014 @ 1200 CDT: The SPC update is out now...

Sunday, May 11, 2014 @ 1300 CDT: Mesoscale Discussion 0562 was just released... Looks like things will start happening at around the time that we get into position. No time to waste!

MESOSCALE DISCUSSION 0562

NWS STORM PREDICTION CENTER NORMAN OK

1249 PM CDT SUN MAY 11 2014

AREAS AFFECTED...N-CNTRL/NE KS...S-CNTRL/SE NEB...FAR SW IA...FAR NW MO

CONCERNING...SEVERE POTENTIAL...TORNADO WATCH LIKELY

VALID 111749Z - 111945Z

PROBABILITY OF WATCH ISSUANCE...95 PERCENT

SUMMARY...SUPERCELL TSTMS ARE EXPECTED TO DEVELOP WITHIN THE NEXT HOUR OR TWO FROM N-CNTRL KS NEWD INTO FAR SW IA. ALL FACETS OF SVR WX ARE POSSIBLE WITH THE POTENTIAL FOR WIND GUSTS GREATER THAN 65 KT...HAIL LARGER THAN 2 INCHES IN DIAMETER...AND TORNADOES...A FEW OF WHICH COULD BE STRONG. AS A RESULT...A TORNADO WATCH WILL BE NEEDED BY 20Z OVER PORTIONS OF THE AREA.

DISCUSSION...RECENT VISIBLE SATELLITE IMAGERY SHOWS AN INCREASINGLY AGITATED AND BUOYANT CU FIELD IN THE VICINITY OF RESIDUAL OUTFLOW BOUNDARIES FROM EARLIER CONVECTION. SURFACE OBSERVATIONS ALSO INDICATE BETTER MOISTURE ACROSS THIS AREA WITH DEWPOINTS IN THE MID TO UPPER 60S. TEMPERATURES SOUTH OF AN OUTFLOW BOUNDARY EXTENDING FROM JUST N OF RSL ENEWD TOWARDS STJ HAVE INCREASE TO ABOVE 80 DEG F.

MODIFICATION OF THE 12Z TOP SOUNDING WITH RECENT OBSERVATIONS YIELDS AN UNCAPPED ENVIRONMENT WITH MLCAPE GREATER THAN 2500 J PER KG. HOWEVER...SOME MID-LEVEL WARMING IS LIKELY ONGOING WITH SOME CONVECTIVE INHIBITION REMAINING. CONTINUED HEATING IS EXPECTED TO ERODE THIS INHIBITION WITH RESULTANT CONVECTIVE INITIATION.

TWX AND EAX VAD PROFILERS SHOW VEERING LOW-LEVEL FLOW WITH TWX RECENTLY MEASURING 219 M2/S2 OF 0-1 KM SRH. CONTINUED NWD PROGRESS OF THE WARM FRONT IS EXPECTED...WITH STRONGLY VEERING WIND PROFILES EXPECTED ACROSS THE WARM SECTOR FROM N-CNTRL KS NEWD INTO FAR SW IA. BULK SHEAR IS ALSO EXPECTED TO INCREASE THROUGHOUT THE AFTERNOON AS A LEAD SHORTWAVE MOVES THROUGH THE CNTRL PLAINS.

THIS ENVIRONMENT WILL READILY SUPPORT SUPERCELLS CAPABLE OF VERY LARGE HAIL /GREATER THAN 2 INCHES IN DIAMETER/...STRONG WINDS...AND TORNADOES...A FEW OF WHICH COULD BE STRONG. AS SUCH...A TORNADO WATCH WILL BE NEEDED ACROSS PORTIONS OF THE AREA BY 20Z.

..MOSIER/MEAD.. 05/11/2014

Sunday, May 11, 2014 @ 1515 CDT: The SPC has updated the Day 1 Tornado Outlook once again... and we are moving again into better position.