brettjrob Posted May 27, 2012 Share Posted May 27, 2012 I'm doing my part to give the setup a little boost by staying home today. My revised target was going to be a 40-mile radius around DDC, as the sfc low and coincident moisture pooling looks somewhat more south on the RAP/HRRR. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 This is the 18z sounding out of MPX could someone help me with reading it? what's your best guess? Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 This is the 18z sounding out of MPX could someone help me with reading it? what's your best guess? That verbatim is fully capped. Ignore the SBCAPE forecast parcel... Would need substantial heating or some rapid mesoscale forcing to lift parcels above that cap/and or eliminate cinh. Not sure if I buy the HRRR depiction of isolated DMC forming ahead of the front based on that sounding...although MPX is farther E than where HRRR initiates. The more likely scenario is that DMC initiates farther SW into NE and possibly eastern SD and propagates into MN. Link to comment Share on other sites More sharing options...
tornadotony Posted May 27, 2012 Share Posted May 27, 2012 This is the 18z sounding out of MPX could someone help me with reading it? what's your best guess? With apologies to Iyaz... There's a lot of subsidence in cap city There's a lot of subsidence in that layer Gotta get the cold front Gotta get the vort max Gotta get somethin' to break that cap... Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 That verbatim is fully capped. Ignore the SBCAPE forecast parcel... Would need substantial heating or some rapid mesoscale forcing to lift parcels above that cap/and or eliminate cinh. Not sure if I buy the HRRR depiction of isolated DMC forming ahead of the front based on that sounding...although MPX is farther E than where HRRR initiates. The more likely scenario is that DMC initiates farther SW into NE and possibly eastern SD and propagates into MN. OK thanks, here is the 18z sounding from Topeka Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 we are caped at H85, that's obvious, but based on these soundings what will the SPC do with the mid afternoon update? The pot sure is on a slow boil here. I'm not sure about Topeka KS and the area around it. Link to comment Share on other sites More sharing options...
jpeters3 Posted May 27, 2012 Share Posted May 27, 2012 RAP predicts an area of enhanced LL SRH to the E of SFC low lobe in south central KS this evening (where LL winds kink a bit more southerly than elsewhere in the state) - also several recent RAP and HRRR runs have developed convection in this region by the 22-00z timeframe. I'm thinking this region may be the most favorable for good supercell structure. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 18z OAX sounding is close eliminating cinh...current obs are now 93/64. I would think storms should be going up within an hour possibly as winds are also beginning to back nicely...acting frontogenetically on the stalled surface boundary. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 RAP predicts an area of enhanced LL SRH to the E of SFC low lobe in south central KS this evening (where LL winds kink a bit more southerly than elsewhere in the state) - also several recent RAP and HRRR runs have developed convection in this region by the 22-00z timeframe. I'm thinking this region may be the most favorable for good supercell structure. That has been the area of interest from 3-4 days ago, but guidance has backed off a tad on low level flow backing...also increasing LCLs. But I agree, could be some nice moderately slow moving, high based sups. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 And I see Carbin already has a much better MCD out, lol. Doesn't discount tor threat. MESOSCALE DISCUSSION 0923 NWS STORM PREDICTION CENTER NORMAN OK 0258 PM CDT SUN MAY 27 2012 AREAS AFFECTED...NE...SD...IA...MN CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 271958Z - 272100Z PROBABILITY OF WATCH ISSUANCE...95 PERCENT SUMMARY...A WATCH WILL BE ISSUED ACROSS PORTIONS OF ERN NEB...WRN IA...AND POSSIBLY SWRN PORTIONS OF MN WITHIN THE NEXT HOUR. CONDITIONS ALONG A COLD FRONT MOVING INTO THESE AREAS SHOULD SUPPORT SEVERE TSTM DEVELOPMENT THROUGH THE REST OF THE AFTERNOON AND INTO THE EVENING. DISCUSSION...SFC ANALYSIS AT 19Z PLACES A NEARLY STALLED COLD FRONT ALONG A LINE FROM MOX IN EXTREME SWRN MN TO LRJ IN NWRN IA TO OFK IN NERN NEB. FRONTAL ZONE CONTINUES ALONG A SWWD LINE TO A TRIPLE-POINT LOW AND DRYLINE ON THE KS/NEB BORDER...ESE OF MCK. WHEN CURRENT SFC CONDITIONS ARE USED TO MODIFY 18Z OBSERVED SOUNDINGS FROM BOTH TOP AND OAX...ALL INDICATIONS POINT TO THE INITIATION OF DEEP CONVECTION WITHIN ANOTHER HOUR OR SO. THIS SCENARIO IS ALSO SUPPORTED BY THE LATEST RR AND HRRR MODELS AND IS CONSISTENT WITH EARLIER SREF GUIDANCE. /NOTE: ANOTHER MCD WILL BE ISSUED SHORTLY FOR TSTM POTENTIAL FROM KS TO OK./ DEEP-LAYER VERTICAL SHEAR MAGNITUDES ON THE ORDER OF 40KT AND MLCAPE IN THE 1200-1800 J/KG RANGE WILL CONTRIBUTE TO ROBUST AND ORGANIZED STORM DEVELOPMENT. REMOVAL OF REMAINING INHIBITION ALONG THE FRONT WILL OCCUR AS DEEP-LAYER ASCENT OVERSPREADS THE REGION THROUGH THE EVENING. THIS SHOULD RESULT IN A SIGNIFICATION INCREASE IN STORMS ALONG THE FRONT AND NEAR THE TRIPLE LOW. AREAL COVERAGE OF THIS ROBUST DEVELOPMENT LENDS CONFIDENCE IN SEVERE WEATHER...ESPECIALLY LARGE HAIL AND DAMAGING WINDS. TORNADO POTENTIAL IS A BIT MORE UNCERTAIN GIVEN RELATIVELY HIGH CLOUD BASES....VEERED LOW LEVEL FLOW AHEAD OF THE FRONT...AND DEEP-LAYER UNIDIRECTIONAL WIND PROFILES EVIDENT IN SOUNDINGS AND VWP/PROFILER DATA ACROSS THE REGION. THESE LIMITATIONS...HOWEVER...CAN BE OFFSET TO SOME DEGREE BY UPDRAFT STRETCHING...STORM INTERACTIONS...AND THE POTENTIAL FOR VERY LOCALIZED AREAS TO EXPERIENCE ENHANCED SR FLOW/HELICITY...SUCH AS NEAR THE TRIPLE POINT LOW. TORNADO THREAT IS ALSO LIKELY GREATER NEARER THE SURFACE LOW AND WARM FRONT IN MN WHERE ANOTHER WATCH MAY BE NEEDED SHORTLY AFTER THIS INITIAL WATCH. Link to comment Share on other sites More sharing options...
tornadotony Posted May 27, 2012 Share Posted May 27, 2012 Setup seems similar to the 5/19 case in KS...would watch the triple point. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 I have friends setting up near Redwood Falls MN, looks good to me, although maybe 50 miles south or thereabouts I think would be better Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 Looks like convective initiation east of Broken Bow. Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 I have friends setting up near Redwood Falls MN, looks good to me, although maybe 50 miles south or thereabouts I think would be better MN has potential...also got a friend who may be chasing up that way. Only worry is cap. Link to comment Share on other sites More sharing options...
jpeters3 Posted May 27, 2012 Share Posted May 27, 2012 That has been the area of interest from 3-4 days ago, but guidance has backed off a tad on low level flow backing...also increasing LCLs. But I agree, could be some nice moderately slow moving, high based sups. RAP runs have actually been backing LL flow a bit more as the day has progressed, and also trended toward more extensive convective development in this region (which it wasn't doing much earlier this morning). Also, TDs are slightly higher to the south (relative to near the KS/NE boarder) with sightly lower sfc temps, presumably equating to slightly lower LCLs (as if it would really make a difference though). Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 from MPX BASED ON SVR WX PARAMETERS...THE MAIN THREAT WILL BE INITIALLY LARGE HAIL...THEN TRANSITION INTO A STRAIGHT LINE WND EVENT. HOWEVER...NEAR THE WARM FRONT ACROSS CENTRAL MN...ISOLATED TORNADOES ARE POSSIBLE...MAINLY BEFORE 8 PM Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 I have friends setting up near Redwood Falls MN, looks good to me, although maybe 50 miles south or thereabouts I think would be better MESOSCALE DISCUSSION 0926 NWS STORM PREDICTION CENTER NORMAN OK 0349 PM CDT SUN MAY 27 2012 AREAS AFFECTED...CNTRL MN INTO NWRN WI CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 272049Z - 272145Z PROBABILITY OF WATCH ISSUANCE...80 PERCENT SUMMARY...WARM SECTOR ACROSS CNTRL MN INTO NWRN WI IS BEING MONITORED FOR A TORNADO WW. CONVECTIVE INITIATION IS POSSIBLE OVER THE NEXT HOUR OR TWO. DISCUSSION...ALTHOUGH THE AREA HAS REMAINED CAPPED BENEATH A STRONG EML...INCREASING FORCING FOR ASCENT WITH AN APPROACHING LARGER SCALE UPPER TROUGH...AND AMPLE SURFACE HEATING /TEMPERATURES IN THE MID 80S F/ ARE CONTRIBUTING TO AN EROSION OF THE REMAINING CONVECTIVE INHIBITION. THE WARM FRONT /PER 20Z SURFACE OBSERVATIONS/ HAS PROGRESSED NWD TO CNTRL MN AND NWRN WI...WHILE A NE-SW ORIENTED COLD FRONT HAS REACHED WRN MN. THE POTENTIAL EXISTS FOR DISCRETE AND ROBUST UPDRAFTS WITHIN THE WARM SECTOR. INITIAL DEVELOPMENT WILL LIKELY BE SUPERCELLULAR...ESPECIALLY INVOF OF THE WARM FRONT WHERE DEEP-LAYER SHEAR VECTORS ARE LARGELY ORTHOGONAL TO THE FRONTAL BOUNDARY. WITH INCREASINGLY FOCUSED SURFACE CONVERGENCE ALONG THE COLD FRONT...A FORCED LINE OF CONVECTION AND SUBSEQUENT WIND THREAT WILL BECOME LIKELY THIS EVENING. ..HURLBUT/CARBIN.. 05/27/2012 Link to comment Share on other sites More sharing options...
brettjrob Posted May 27, 2012 Share Posted May 27, 2012 The current dew points across the southern and central Plains, given several days of uninterrupted southerlies down to the Gulf Coast in late May, are just wrong. Not sure I've ever seen anything like it this late in the season. Surface maps like this would normally be reserved for last-minute moisture situations within 24 hrs. of return flow commencing -- if anything. Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 living here in the north metro, for the first time today I'm starting to see some upward motion to the ne of me. Game is about to begin IMO Can't see much to the sw of me, to many trees, we live in a nice mature area of Champlin MN Link to comment Share on other sites More sharing options...
baroclinic_instability Posted May 27, 2012 Share Posted May 27, 2012 living here in the north metro, for the first time today I'm starting to see some upward motion to the ne of me. Game is about to begin IMO Can't see much to the sw of me, to many trees, we live in a nice mature area of Champlin MN May have to wait a bit, CU look flat on vis, cap still holding. If a few can go though, potential definitely exists. Are you out chasing? Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 this is from MPX BASED ON SVR WX PARAMETERS...THE MAIN THREAT WILL BE INITIALLY LARGE HAIL...THEN TRANSITION INTO A STRAIGHT LINE WND EVENT. HOWEVER...NEAR THE WARM FRONT ACROSS CENTRAL MN...ISOLATED TORNADOES ARE POSSIBLE...MAINLY BEFORE 8 PM Link to comment Share on other sites More sharing options...
Minnesota Meso Posted May 27, 2012 Share Posted May 27, 2012 May have to wait a bit, CU look flat on vis, cap still holding. If a few can go though, potential definitely exists. Are you out chasing? Not chasing, that's not my thing, once a event happens, I'm on to the next one, I really enjoy forecasting a event as opposed to chasing it. Link to comment Share on other sites More sharing options...
Ian Posted May 27, 2012 Share Posted May 27, 2012 We've been watching the dry line near Franklin NE for quite a while not.. struggling mainly so far, though it might be getting closer. Mini convergence with Laubach crashing our party. Everyone else seems to be biting but we'll wait. Link to comment Share on other sites More sharing options...
MNstorms Posted May 27, 2012 Author Share Posted May 27, 2012 Storms popped up in South Minnesota. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 27, 2012 Share Posted May 27, 2012 Nice couplet organizing south of Greely Center. Link to comment Share on other sites More sharing options...
brettjrob Posted May 27, 2012 Share Posted May 27, 2012 TOG in Antelope Co., NE. LCLs are slightly better up there, though still quite marginal. EDIT: Next cell down the line in Greeley Co. looking relatively similar in terms of velocity presentation. Link to comment Share on other sites More sharing options...
SouthernNJ Posted May 27, 2012 Share Posted May 27, 2012 Quite a large supercell about 30 miles west of Norfolk NE. This thing could produce some significant hail. Link to comment Share on other sites More sharing options...
SouthernNJ Posted May 27, 2012 Share Posted May 27, 2012 Nice couplet organizing south of Greely Center. This one conceivably could've had a warning upgrade based on the 513 velocity scan, we'll see if anything gets reported. Link to comment Share on other sites More sharing options...
hm8 Posted May 27, 2012 Share Posted May 27, 2012 NE cells spitting out tennis balls, couple of 2.5" reports Link to comment Share on other sites More sharing options...
Indystorm Posted May 27, 2012 Share Posted May 27, 2012 Interesting to watch training supercells in eastern Nebraska moving into an area of higher CAPE, better moisture, good bulk shear and increasing helicity. Could be an interesting evening. Link to comment Share on other sites More sharing options...
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