jcwxguy Posted May 18, 2013 Share Posted May 18, 2013 passing through pratt now, should be in greensburg in half an hour Link to comment Share on other sites More sharing options...
CUmet Posted May 18, 2013 Share Posted May 18, 2013 For what it's worth, the 12z ECMWF definitely has pulled the dryline across northern OK and KS back towards the west, having a more N-S orientation than the previous few runs. Associated with this is a trend towards more backed surface winds across OK as well.I'm becoming slowly more confident in a major tornado outbreak occurring on Sunday, focused on central/northern OK and into southern KS. Frankly I'm a little concerned that brettjrob is so bearish about it, because he's an excellent severe wx forecaster. Link to comment Share on other sites More sharing options...
andyhb Posted May 18, 2013 Share Posted May 18, 2013 MESOSCALE DISCUSSION 0675 NWS STORM PREDICTION CENTER NORMAN OK 0209 PM CDT SAT MAY 18 2013 AREAS AFFECTED...NWRN KS...NERN CO AND WRN NEB CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 181909Z - 182045Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...STORMS ARE EXPECTED TO INITIATE BY 20-21Z FROM NERN CO INTO NWRN KS AND EXTREME SERN WY...THEN SUBSEQUENTLY DEVELOP NEWD INTO WRN NEB DURING THE EVENING. PRIMARY THREATS WILL BE VERY LARGE HAIL AND ISOLATED TORNADOES. STORMS MAY EVENTUALLY GROW UPSCALE INTO ONE OR MORE CLUSTERS LATER IN THE EVENING WITH AN INCREASING THREAT FOR DAMAGING WIND. A TORNADO WATCH WILL LIKELY BE NEEDED PRIOR TO 21Z. DISCUSSION...THIS AFTERNOON A DRYLINE EXTENDS FROM SERN WY TO A MESOLOW NEAR THE KS/CO BORDER THEN FARTHER SWD THROUGH SWRN KS. THE LATEST OBJECTIVE ANALYSIS INDICATES THE WARM SECTOR HAS BECOME VERY UNSTABLE IN CORRIDOR FROM NWRN KS THROUGH EXTREME NERN CO AND WRN NEB WHERE VERY STEEP LAPSE RATES /APPROACHING 9 C/KM/ HAVE OVERSPREAD THE MOIST AXIS. SPECIAL 18Z RAOB FROM NORTH PLATTE NEB INDICATES A STRONG CAPPING INVERSION IS STILL IN PLACE JUST BELOW 700 MB IN ASSOCIATION WITH WARM AIR AT BASE OF THE EML. THIS SUGGESTS THUNDERSTORM INITIATION WILL LIKELY BE FARTHER WEST ACROSS NERN CO AND NWRN KS. SATELLITE IMAGERY SHOWS MID-LEVEL CONVECTION SPREADING RAPIDLY NWD ACROSS NERN CO AND NWRN KS AND APPEARS TO BE IN ASSOCIATION WITH MID-LEVEL ASCENT ACCOMPANYING A NEWD EJECTING SHORTWAVE TROUGH. FORCING FROM THIS FEATURE AND DEEPER MIXING OVER THE HIGH PLAINS OF NERN CO THROUGH WRN KS WILL LIKELY SUPPORT THUNDERSTORM INITIATION ALONG THE DRYLINE SOMETIME DURING THE NEXT COUPLE HOURS. VERTICAL SHEAR THROUGH A DEEP LAYER WILL REMAIN SUFFICIENT FOR SUPERCELLS CAPABLE OF VERY LARGE HAIL GIVEN THE FAVORABLE LAPSE RATES AND STRONG INSTABILITY. ALSO...THE THREAT FOR ISOLATED TORNADOES IS EXPECTED TO INCREASE IN WINDOW FROM LATE AFTERNOON INTO EARLY EVENING AS THE LLJ STRENGTHENS AND BEFORE THE BOUNDARY LAYER DECOUPLES AND WHILE SOME STORMS MAY STILL BE DISCRETE. STORMS MAY EVENTUALLY CONGEAL INTO ONE OR MORE CLUSTERS DURING THE EVENING...WITH AN ATTENDANT INCREASE IN DAMAGING WIND THREAT. ..DIAL/KERR.. 05/18/2013 Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 Just got off an awesome forty five minute long conference with a few old buddies of mine and I finally decided to pull the trigger on my first Plains chase in about nine years. Just booked a flight for Monday morning to OKC and I'll meet up with everyone in Tulsa, for what looks to be an extremely interesting chase day on Monday. Last time I was out here was during the record breaking May 2004 sequence, so I hope we can pull off something interesting once again. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 DDC is currently at 93/59 Western portions of the MDT risk in SW Kansas look to have some moisture issues. Link to comment Share on other sites More sharing options...
brettjrob Posted May 18, 2013 Share Posted May 18, 2013 For what it's worth, the 12z ECMWF definitely has pulled the dryline across northern OK and KS back towards the west, having a more N-S orientation than the previous few runs. Associated with this is a trend towards more backed surface winds across OK as well. I'm becoming slowly more confident in a major tornado outbreak occurring on Sunday, focused on central/northern OK and into southern KS. Frankly I'm a little concerned that brettjrob is so bearish about it, because he's an excellent severe wx forecaster. Don't be. I'm already starting to back down, and my primary reasoning before was basically just that the NAM was so bearish and has been correct in its bearishness several times this season. But with both a global (ECMWF) and hi-res mesoscale (WRF-NMM) model trending rapidly more favorable, I'm quickly leaning in that direction. My bearishness also wasn't so much categorically bearish, but rather arguing the "floor" on Sunday was rather low for such a hyped event. However, I've always thought the ceiling was quite high, and the floor seems to be rising now. If the dryline stays well W of I-35 and is oriented due N-S (or even bends back to the NW), I imagine something in the ballpark of 5/24/11 will be possible. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 18, 2013 Share Posted May 18, 2013 Greensburg chaser convergence with CU to the west. Link to comment Share on other sites More sharing options...
brettjrob Posted May 18, 2013 Share Posted May 18, 2013 Also, regarding today, the convection-allowing models have clearly taken a stand in favor of the southern target, with nearly all of them initiating explosive supercells somewhere in the PTT-WWR vicinity late afternoon. However, current sfc obs have me this close to blasting N to at least I-70. Absolutely primed environment N of HYS with obs of ~82/70 and SE sfc winds. Storms initiating down S will likely be initially high-based, but eventually move into a much better environment -- just hope they don't go outflow-dominant in the interim. Link to comment Share on other sites More sharing options...
Srain Posted May 18, 2013 Share Posted May 18, 2013 MESOSCALE DISCUSSION 0676 NWS STORM PREDICTION CENTER NORMAN OK 0219 PM CDT SAT MAY 18 2013 AREAS AFFECTED...SWRN KS...WRN OK...NW TX...FAR ERN OK/TX PANHANDLES CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 181919Z - 182015Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...SCATTERED TSTM INITIATION IS EXPECTED ON THE DRYLINE BY 21-22Z. VERY LARGE HAIL...ISOLATED TORNADOES...AND DAMAGING WIND WILL BE POSSIBLE. WATCH ISSUANCE IS EXPECTED IN THE NEXT HOUR OR SO. DISCUSSION...LATEST SFC ANALYSIS DEPICTS THE DRYLINE EXTENDING FROM SWRN KS INTO THE FAR ERN OK/TX PANHANDLES AND NW TX. VIS IMAGERY SHOWS CU INCREASING IN THE WELL-MIXED AIRMASS IN THE VICINITY OF THE DRYLINE ACROSS SW KS INTO THE TX PANHANDLE. WHILE ONE EMBEDDED VORT MAX IS MOVING NWD OUT OF THE AREA...ANOTHER EMBEDDED VORT MAX OVER SERN CO/NERN NM SHOULD AID IN CONVECTIVE INITIATION LATER THIS AFTERNOON. THE 18Z DDC SOUNDING SHOWS VERY STEEP LAPSE RATES IN EXCESS OF 9.5 C/KM IN THE 750-500 MB LAYER...WHICH WILL SUPPORT VERY HIGH TO EXTREME MLCAPE OF 3000-4000 J/KG IN AREAS AHEAD OF THE DRYLINE THIS AFTERNOON AND EARLY EVENING. WHILE FLOW IS RELATIVELY MODEST...INCREASING SWLY MIDLEVEL FLOW IS SUPPORTING EFFECTIVE SHEAR OF 35-45 KTS AHEAD OF THE DRYLINE...WHICH WILL BE MORE THAN SUFFICIENT FOR SUPERCELL DEVELOPMENT UPON STORM INITIATION. DISCRETE SUPERCELL ACTIVITY IS EXPECTED WITHIN THE FIRST 2-3 HOURS OF INITIATION...WITH VERY LARGE HAIL IN EXCESS OF BASEBALL SIZE THE PRIMARY THREAT. LARGE T/TD SPREADS AND RELATIVELY WEAK LOW-LEVEL SHEAR WILL LIMIT THE TORNADO THREAT INITIALLY...BUT A MARKED INCREASE IN THE LOW-LEVEL JET WILL INCREASE THE TORNADO THREAT TOWARD EVENING ACROSS MAINLY NWRN OK INTO SWRN KS...WITH ISOLATED STRONG TORNADOES POSSIBLE WITH ANY STORMS THAT CAN REMAIN DISCRETE AFTER 00Z. HOWEVER...STORM CONSOLIDATION IN A WELL-MIXED ENVIRONMENT MAY RESULT IN UPSCALE GROWTH AND A TRANSITION TO MORE OF A SEVERE WIND THREAT THIS EVENING...POSSIBLY LIMITING THE WINDOW OF OPPORTUNITY FOR A MORE ROBUST TORNADO THREAT. ..DEAN/KERR.. 05/18/2013 ATTN...WFO...ICT...FWD...OUN...DDC...SJT...GLD...LUB...AMA... Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 Anyone have a good satellite feed? SPC's is not working. Also, new MD up with 95% probability tor issuence. Mentions strong tor possibility for any discrete storm past 00z. Link to comment Share on other sites More sharing options...
David Reimer Posted May 18, 2013 Share Posted May 18, 2013 Greensburg chaser convergence with CU to the west. Come over to the Best Western on the west side of town and say hi! We're in the lobby. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 TCU just west of DDC Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 ^More poppers in W OK and TX panhandle. Initiation likely coming within 60 minutes. Link to comment Share on other sites More sharing options...
Coreyback Posted May 18, 2013 Share Posted May 18, 2013 Anyone have a good satellite feed? SPC's is not working. Also, new MD up with 95% probability tor issuence. Mentions strong tor possibility for any discrete storm past 00z. As with most of their web stuff, College of DuPage has pretty solid satellite pages. 1km/2km sectors, some overlays, and whatnot. Plays nice on mobile, too, at least on my Nexus tablet. http://weather.cod.edu/satrad/ Link to comment Share on other sites More sharing options...
CT Rain Posted May 18, 2013 Share Posted May 18, 2013 It's awfully dry around 850mb on the 18z DDC soundings. The 12z NAM does push that drier air northeast and advects in some moisture after 21z and especially by 00z. This moisture return will obviously have big implications on eroding that cap and where the cap goes first. Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 DDC still down? Oh boy. That stinks. Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 18, 2013 Share Posted May 18, 2013 NAM-based CIPS analog guidance for 00Z tomorrow includes 05/29/2004 in first place, then 06/04/2005, 05/02/2008, 05/17/1991, 04/26/1991...and to this I might add 05/02/1942 (six F4s in NE OK/SE KS) based upon NCAR 20c Reanalysis's H5 archive. Here is the chart from 18Z on that last date. Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 As with most of their web stuff, College of DuPage has pretty solid satellite pages. 1km/2km sectors, some overlays, and whatnot. Plays nice on mobile, too, at least on my Nexus tablet. http://weather.cod.edu/satrad/ Exactly what I needed. Thank you! Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 DDC still down? Oh boy. That stinks. DDC is fine. L2/L3 feeds are both responding with no issues. Link to comment Share on other sites More sharing options...
andyhb Posted May 18, 2013 Share Posted May 18, 2013 NAM-based CIPS analog guidance for 00Z tomorrow includes 05/29/2004 in first place, then 06/04/2005, 05/17/1991, 04/26/1991...and to this I might add 05/02/1942 (six F4s in NE OK/SE KS) based upon NCAR 20c Reanalysis's H5 archive. Three of those events (from the CIPS) had large tornadoes in the vicinity of Wichita. Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 DDC is fine. L2/L3 feeds are both responding with no issues. You are right. Thanks Link to comment Share on other sites More sharing options...
icebreaker5221 Posted May 18, 2013 Share Posted May 18, 2013 The rapid strengthening of the LL jet from 00Z - 06Z across N OK / S KS is telling. Both GFS and NAM have nothing over 35 kt at 850 mb at 21Z, and both have isolated 60 kt + by 06Z. Really reminds me of a similar intensification of the LL jet in the same locations as 05-05-2007 00Z-06Z (Greensburg tornado). Only question is whether or not storms will be able to take full advantage of that subsequent LL helicity by remaining discrete, or if we'll just have one big MCS by then. Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 What layer is best to see shear? Bulk? Talking about on SPC meso feeds. Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 And away we go WW170 http://www.spc.noaa.gov/products/watch/ww0170.html Link to comment Share on other sites More sharing options...
andyhb Posted May 18, 2013 Share Posted May 18, 2013 What layer is best to see shear? Bulk? Talking about on SPC meso feeds. What? I depends on what type of shear you want to look at, if you are looking for 0-3 km/0-1 km/effective helicity, it should be there, along with 0-1 km shear, 0-6 km bulk shear, effective bulk shear, etc. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 Large tornado watch just issued. Covers portions of NE/CO/KS Link to comment Share on other sites More sharing options...
SquatchinNY Posted May 18, 2013 Share Posted May 18, 2013 Pretty towers NE of Garden City. Link to comment Share on other sites More sharing options...
Ground Scouring Posted May 18, 2013 Share Posted May 18, 2013 That warm temperature bulge at 700 mb over the TX Panhandle could help initiate gravity waves near DDC within the hour, thus both preventing an early MCS and providing fuel for initiation once the cap erodes around 00Z. Any delay in initiation, which is what we are seeing now relative to the NAM (which initiated storms by 21Z), would favor more discrete storms as the LLJ intensifies in the coming hours. Link to comment Share on other sites More sharing options...
Superstorm93 Posted May 18, 2013 Share Posted May 18, 2013 19z (f01) Run of the RAP must have had a glitch or something. The SBCAPE values are up to 8500 j/KG just south of ICT 70/20 Tor probs on this watch DISCUSSION...INITIATION OF SEVERE STORMS IS EXPECTED DURING THE NEXT FEW HOURS...BOTH WITHIN MOIST UPSLOPE FLOW NEAR THE LEE SURFACE TROUGH ACROSS PARTS OF WESTERN NEBRASKA INTO NORTHEAST/EAST CENTRAL COLORADO...AND ALONG THE DRYLINE ACROSS PARTS OF WESTERN KANSAS. AS ACTIVITY SPREADS NORTHWARD/NORTHEASTWARD WITHIN A VERY UNSTABLE ENVIRONMENT...VERY LARGE HAIL AND A FEW TORNADOES APPEAR POSSIBLE WITH STRONGEST STORMS INTO EARLY EVENING. TORNADIC POTENTIAL MAY BE A BIT SLOWER TO DEVELOP AHEAD OF THE DRYLINE ACROSS KANSAS...THAN IN THE COOLER UPSLOPE REGIME TO THE NORTHWEST...BUT LOW-LEVEL JET STRENGTHENING AND INCREASING BOUNDARY LAYER RELATIVE HUMIDITY WILL SUPPORT A WINDOW OF OPPORTUNITY FOR ONE OR TWO STRONG TORNADOES ACROSS PARTS OF WESTERN INTO CENTRAL KANSAS NEAR/SHORTLY AFTER SUNSET. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 18, 2013 Share Posted May 18, 2013 Come over to the Best Western on the west side of town and say hi! We're in the lobby. We're sitting at the Kwik Shop with pretty much everyone else lol. Link to comment Share on other sites More sharing options...
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