jojo762 Posted May 11, 2014 Share Posted May 11, 2014 Amazing plume of L-LVL moisture in extreme SE NE. WF still hasn't made it to Lincoln/ Omaha yet.. South of the warm front DP's ~70 degrees with ~80 degree temps, north of the WF still at ~mid/upper 50's DP's and temps AOA 65... quite a gradient in air masses. Warm front has appeared to be fairly quasi-stationary IMO since 13Z with a little movement toward the north. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 11, 2014 Share Posted May 11, 2014 Currently on I-80 between DSM and OMA. Heading to around Beatrice, NE. Link to comment Share on other sites More sharing options...
CUmet Posted May 11, 2014 Share Posted May 11, 2014 Environment in the Omaha area is looking ugly later on as the warm front moves north and assumes a position where it's essentially intersecting the metro with extreme low level backing in place (a bit like 4/27 in the Little Rock area) and a plume of steep mid level lapse rates associated with the EML is overspreading the region pretty nicely. Agreed, it looks like the Lincoln-Omaha corridor is going to be the prime location for a significant tornado threat. The last few HRRR runs have been placing the warm front along this line or a tad bit south of there, and they all have been developing a lead cell or two with massive updraft helicity. I think this is the type of setup where you'll get that one cell that goes crazy and produces significant tornadoes, while everything behind that cell lines out pretty quickly as the cold front advances. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 With mid 60s dews south of the front and an EML with near 8.5 C/km mid level lapse rates, that's a pretty explosive combination especially blended with the low LCL heights. Link to comment Share on other sites More sharing options...
tornadotony Posted May 11, 2014 Share Posted May 11, 2014 Agreed, it looks like the Lincoln-Omaha corridor is going to be the prime location for a significant tornado threat. The last few HRRR runs have been placing the warm front along this line or a tad bit south of there, and they all have been developing a lead cell or two with massive updraft helicity. I think this is the type of setup where you'll get that one cell that goes crazy and produces significant tornadoes, while everything behind that cell lines out pretty quickly as the cold front advances. Agreed. With the apparent most favorable corridor being one of the most populated areas under risk, it's disconcerting. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 MESOSCALE DISCUSSION 0562NWS 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 Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 11, 2014 Share Posted May 11, 2014 Agreed, it looks like the Lincoln-Omaha corridor is going to be the prime location for a significant tornado threat. The last few HRRR runs have been placing the warm front along this line or a tad bit south of there, and they all have been developing a lead cell or two with massive updraft helicity. I think this is the type of setup where you'll get that one cell that goes crazy and produces significant tornadoes, while everything behind that cell lines out pretty quickly as the cold front advances. The HRRR literally targets Omaha l Resolves two intense supercells within its 3km grid with every severe parameter maxed out. Shows an insane amount of UH as well as surface wind gusts near 90mph. Link to comment Share on other sites More sharing options...
jojo762 Posted May 11, 2014 Share Posted May 11, 2014 Anybody think the SPC will go PDS with this? Given the obvious explosive and volatile environment it seems warranted... They might do what they did a few weeks ago on 4/27 and go TOR watch then go PDS if the higher tornado threat is becoming more blatant. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 Another concern is that the storm motions today will favour storms moving parallel to the WF rather than across it (like 4/27) so any supercells that can stay out ahead could track into IA as well where the environment looks to recover quite quickly this afternoon. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 Very intense mid level rotation on the tornado warned storm in IA, it is emerging from that cluster nicely and is looking a lot more supercellular as of the last few scans. Link to comment Share on other sites More sharing options...
Chinook Posted May 11, 2014 Share Posted May 11, 2014 they have issued another tornado warning for that embedded cell in Iowa (Russel, Iowa) Link to comment Share on other sites More sharing options...
thewxmann Posted May 11, 2014 Share Posted May 11, 2014 Anybody think the SPC will go PDS with this? Given the obvious explosive and volatile environment it seems warranted... They might do what they did a few weeks ago on 4/27 and go TOR watch then go PDS if the higher tornado threat is becoming more blatant. Tornado risk is only at 10% right now... probably not high enough to warrant PDS. Link to comment Share on other sites More sharing options...
SmokeEater Posted May 11, 2014 Share Posted May 11, 2014 Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 11, 2014 Share Posted May 11, 2014 Tornado risk is only at 10% right now... probably not high enough to warrant PDS. Agreed. The threat is too localized and is likely to be restricted to one or two (F2+) tornado-producing cells. Link to comment Share on other sites More sharing options...
wxmeddler Posted May 11, 2014 Share Posted May 11, 2014 MD for dryline. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 Cell WNW of Ottumwa, IA is really wrapping up, inflow is very strong. Link to comment Share on other sites More sharing options...
jojo762 Posted May 11, 2014 Share Posted May 11, 2014 KTOP sounding at 18Z is very odd. Shows SBCAPE and MLCAPE both under 1000J/KG and 0-1km shear of 14kts w/ 74m2/s2 of SRH, and 0-3km shear of 32kts w/ 166m2/s2 of SRH. Supercell composite of only 1. Interestingly the VAD profiler from TWX shows a much different picture, as well as SPC mesoanalysis. Any idea as to why this is? Obviously KTOP isn't in the main threat area, but it isnt too far south/east Link to comment Share on other sites More sharing options...
Stebo Posted May 11, 2014 Share Posted May 11, 2014 KTOP sounding at 18Z is very odd. Shows SBCAPE and MLCAPE both under 1000J/KG and 0-1km shear of 14kts w/ 74m2/s2 of SRH, and 0-3km shear of 32kts w/ 166m2/s2 of SRH. Supercell composite of only 1. Interestingly the VAD profiler from TWX shows a much different picture, as well as SPC mesoanalysis. Any idea as to why this is? Obviously KTOP isn't in the main threat area, but it isnt too far south/east The transmission ended at only 400mb so the top half of the sounding is missing. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 KTOP sounding at 18Z is very odd. Shows SBCAPE and MLCAPE both under 1000J/KG and 0-1km shear of 14kts w/ 74m2/s2 of SRH, and 0-3km shear of 32kts w/ 166m2/s2 of SRH. Supercell composite of only 1. Interestingly the VAD profiler from TWX shows a much different picture, as well as SPC mesoanalysis. Any idea as to why this is? Obviously KTOP isn't in the main threat area, but it isnt too far south/east The sounding didn't sample the entire troposphere, for one. You can tell the CAPE profile is impressive. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 What a hook west of Ottumwa. Link to comment Share on other sites More sharing options...
SmokeEater Posted May 11, 2014 Share Posted May 11, 2014 Link to comment Share on other sites More sharing options...
wxmeddler Posted May 11, 2014 Share Posted May 11, 2014 Tor Watch from IA watch border along the WF down to near Hays.KS Link to comment Share on other sites More sharing options...
Disc Posted May 11, 2014 Share Posted May 11, 2014 Beatrice, NE is 81/68 as of 2pm. Looks like the front is now somewhere between Beatrice and Omaha. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 That supercell in IA could be going for awhile, has a very intense updraft. Link to comment Share on other sites More sharing options...
Indystorm Posted May 11, 2014 Share Posted May 11, 2014 Sig tor up to 5 south of Hastings to Superior. Does not bode well for the Lincoln/Omaha corridor NE of there. Link to comment Share on other sites More sharing options...
andyhb Posted May 11, 2014 Share Posted May 11, 2014 Tornado watch for NE/IA, 80/50 tornado probs. URGENT - IMMEDIATE BROADCAST REQUESTEDTORNADO WATCH NUMBER 142NWS STORM PREDICTION CENTER NORMAN OK220 PM CDT SUN MAY 11 2014THE NWS STORM PREDICTION CENTER HAS ISSUED A* TORNADO WATCH FOR PORTIONS OFSOUTHWEST IOWANORTH-CENTRAL AND NORTHEAST KANSASFAR NORTHWEST MISSOURISOUTH-CENTRAL AND EASTERN NEBRASKA* EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 220 PM UNTIL1000 PM CDT.* PRIMARY THREATS INCLUDE...SEVERAL TORNADOES LIKELY WITH A COUPLE INTENSE TORNADOESPOSSIBLESCATTERED LARGE HAIL LIKELY WITH ISOLATED VERY LARGE HAIL EVENTSTO 2.5 INCHES IN DIAMETER POSSIBLEISOLATED DAMAGING WIND GUSTS TO 70 MPH POSSIBLETHE TORNADO WATCH AREA IS APPROXIMATELY ALONG AND 60 STATUTEMILES NORTH AND SOUTH OF A LINE FROM 70 MILES SOUTH SOUTHWEST OFKEARNEY NEBRASKA TO 35 MILES NORTHEAST OF SHENANDOAH IOWA. FOR ACOMPLETE DEPICTION OF THE WATCH SEE THE ASSOCIATED WATCH OUTLINEUPDATE (WOUS64 KWNS WOU2).PRECAUTIONARY/PREPAREDNESS ACTIONS...REMEMBER...A TORNADO WATCH MEANS CONDITIONS ARE FAVORABLE FORTORNADOES AND SEVERE THUNDERSTORMS IN AND CLOSE TO THE WATCHAREA. PERSONS IN THESE AREAS SHOULD BE ON THE LOOKOUT FORTHREATENING WEATHER CONDITIONS AND LISTEN FOR LATER STATEMENTSAND POSSIBLE WARNINGS.&&OTHER WATCH INFORMATION...CONTINUE...WW 141...DISCUSSION...EXPLOSIVE TSTM DEVELOPMENT IS ANTICIPATED FROM JUSTNORTHEAST OF A SURFACE LOW OVER NORTH-CENTRAL KANSAS NORTHEAST ALONGA WARM FRONT MOVING NORTH THROUGH EASTERN NEBRASKA AND WESTERN IA.GIVEN THE COMBINATION OF MODERATE TO STRONG INSTABILITY AND STRONGLOW-LEVEL AND DEEP-LAYER SHEAR...THE ENVIRONMENT WILL BE QUITEFAVORABLE FOR LONG-LIVED SUPERCELLS CAPABLE OF VERY LARGE HAIL ANDTORNADOES...A COUPLE OF WHICH COULD BE INTENSE.AVIATION...TORNADOES AND A FEW SEVERE THUNDERSTORMS WITH HAILSURFACE AND ALOFT TO 2.5 INCHES. EXTREME TURBULENCE AND SURFACEWIND GUSTS TO 60 KNOTS. A FEW CUMULONIMBI WITH MAXIMUM TOPS TO500. MEAN STORM MOTION VECTOR 24030....MEAD Link to comment Share on other sites More sharing options...
Derecho! Posted May 11, 2014 Share Posted May 11, 2014 Sig tor up to 5 south of Hastings to Superior. Does not bode well for the Lincoln/Omaha corridor NE of there. Tops out at 7. Link to comment Share on other sites More sharing options...
wxmeddler Posted May 11, 2014 Share Posted May 11, 2014 Impressive taking into account the local backing near the WF. Link to comment Share on other sites More sharing options...
Chinook Posted May 11, 2014 Share Posted May 11, 2014 A few cells are popping near Dodge City Link to comment Share on other sites More sharing options...
SmokeEater Posted May 11, 2014 Share Posted May 11, 2014 Initiation near Red Cloud, NE. Link to comment Share on other sites More sharing options...
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