Iceresistance Posted April 26, 2022 Share Posted April 26, 2022 12z Canadian still breaks the Cap on Thursday's & Friday's setups. Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 26, 2022 Meteorologist Share Posted April 26, 2022 (edited) FWIW, Euro doesn't have capping issues at 0z but instability and shear are weaker than GFS. GFS continues to have a window of opportunity in SE KS from 21z to ~23z for some really nasty supercells. Initiation at 21z is pretty early for the Plains Good call regarding making this a 'sequence' thread. I knew any break in severe weather would be temporary and we'd return to the same old... but not this quick. With a persistent flow of systems entering the US through the west coast, one of these events has to produce something at some point, somewhere. CIPS analogs likes a Plains-to-Ohio Valley conveyor belt This follows climatology pretty well. With the exclusion of the Southeast and secondary focus on the Mid-MS Valley/Ohio Valley, it's safe to assume the analogs chosen include a SE high pressure. Don't want to jinx it but I think the Southeast is done with organized severe weather until the Fall. Finally. Edited April 26, 2022 by ClicheVortex2014 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 26, 2022 Meteorologist Share Posted April 26, 2022 (edited) 18z NAM is similar to GFS in the sense that there's basically no cap at 21z but the cap returns strong at 0z. There's quite the difference in location of greatest parameters though. Below are some area average soundings. Very strong instability with sufficient shear would mean significant wind/significant hail potential. However, LCL is slightly above 1km which is getting kinda high. If we were to assume NAM is completely right about this and semi-discrete storms are going to develop, I could see a 10% hatched tornado but the LCL is really a limiting factor for anything higher than that. Edited April 26, 2022 by ClicheVortex2014 1 Link to comment Share on other sites More sharing options...
Iceresistance Posted April 26, 2022 Share Posted April 26, 2022 I really don't trust the CFSv2, it's showing a May 3rd, 1999 Repeat over Oklahoma. Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 26, 2022 Meteorologist Share Posted April 26, 2022 OUN and ICT are ramping up wording in their AFDs. Both are mentioning a possible, albeit conditional, high-impact event. ICT The chances of developing severe storms increase as we move into Friday as a wide based western CONUS trough axis approaches the Rockies. This time, the dry line may bisect portions of central and south central KS during peak heating. There remains some differences in the progression of the dryline and trailing cold front between models. There looks like there will be much better convergence along the dryline to help convective initiation although once again there looks to be a strong cap in place over much of the area. Should storms develop, all severe hazards, potentially significant, would be possible. A low probability, high impact event is possible. This period will be watched closely in the coming days. OUN For Friday, a negatively-tilted shortwave trough is progged to dig into the Central Plains as it begins to close. As this occurs, a surface low is forecast to deepen and accelerate across Kansas. Gusty southerly winds are expected Friday afternoon in response to the strengthening surface low. The trailing dryline will advance eastward in tandem with the surface low--just west of Highway 81 by Friday afternoon. Ahead of the dryline, the environment will be conditionally favorable for severe thunderstorms. The environment will be characterized by MLCAPE of 2500 to 3000+ J/kg with effective bulk shear ~40 to 45 knots, which is sufficient for supercells. Note that there is some weakness in the wind fields aloft (when compared to the low-levels) given the track of the trough farther to the north. Essentially, wind shear is weak above ~3 km. This may favor more high precipitation (HP) supercells given the weak storm-relative winds aloft. Nevertheless, enlarged, looping low- level hodographs will result in a risk of tornadoes with any supercells. The risk for severe thunderstorms is conditional. In other words, the parameters for severe thunderstorms exist, but can only be realized if storms are able to form. Forecast soundings indicate there will be a cap present. While the greatest ascent to lift the cap will be to the north, there might be sufficient lift farther south with some subtle DPVA (differential positive vorticity advection) combined with the dryline circulation for convection-- especially given the close proximity of the trough. Bottom line: Be prepared for severe weather Friday as the potential for a higher-end severe risk is there *if* the cap breaks. West of dryline, critical to extreme fire weather conditions are forecast as relative humidity values fall to near 10% or lower. ERC values across the far west (near the 100th meridian) and northwest Oklahoma are at or above the 90th percentile, so the fuels remain volatile in this region (given the lack of rainfall/ongoing drought). A Fire Weather Watch will likely be needed in subsequent shifts. Tulsa The greatest potential for severe weather will occur on Friday across much of eastern Oklahoma and western Arkansas. However, the the potential will be conditional in nature. A dry line is forecast to surge into western/central Oklahoma Friday afternoon/ evening. The airmass in advance of the dry line is forecast to be strongly capped during this time. Despite the cap, a few storms may be able to initiate in the vicinity of the dry line Friday evening as a mid-level shortwave moves across Kansas. Any storms that do develop will likely become severe with all modes of severe weather possible as they spread into the area. 2 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 26, 2022 Meteorologist Share Posted April 26, 2022 Great thread from the SPC forecaster who wrote yesterday and todays day 4-8 outlook 3 Link to comment Share on other sites More sharing options...
Meteorologist Ingyball Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 3 hours ago, ClicheVortex2014 said: 18z NAM is similar to GFS in the sense that there's basically no cap at 21z but the cap returns strong at 0z. There's quite the difference in location of greatest parameters though. Below are some area average soundings. Very strong instability with sufficient shear would mean significant wind/significant hail potential. However, LCL is slightly above 1km which is getting kinda high. If we were to assume NAM is completely right about this and semi-discrete storms are going to develop, I could see a 10% hatched tornado but the LCL is really a limiting factor for anything higher than that. The Plains seem to be able to produce tornadoes even with higher LCLs around 1km. DDCs 19z sounding on Friday had LCLs around 1500m, not sure if those same LCLs were present in Goodland's area or not though. There is a study that I just looked up that talks about this. I only read the abstract, but it suggest other thermodynamic processes can overcome high LCLs. Though the cap also needs to be weak it appears as well. https://journals.ametsoc.org/view/journals/wefo/21/4/waf928_1.xml 1 Link to comment Share on other sites More sharing options...
Cincysnow Posted April 27, 2022 Share Posted April 27, 2022 Often, I need to look up some of the met talk (weather acronyms), and stumbled across this today. A good source of info related to acronyms and the definition of each: https://www.weather.gov/source/zhu/ZHU_Training_Page/convective_parameters/Sounding_Stuff/MesoscaleParameters.html 1 1 Link to comment Share on other sites More sharing options...
Meteorologist Ingyball Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 11 minutes ago, Cincysnow said: Often, I need to look up some of the met talk (weather acronyms), and stumbled across this today. A good source of info related to acronyms and the definition of each: https://www.weather.gov/source/zhu/ZHU_Training_Page/convective_parameters/Sounding_Stuff/MesoscaleParameters.html I know on wxdicso they had some of our lingo underlined that gave a brief description, that could be a good thing to add. @Uscg Ast Otherwise I'll try to make it a point to at least spell out the abbreviations going forward. 2 1 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 (edited) NAM is looking a lot like GFS now. At least the supercell composite map does on the surface. Capping issues along most of the dryline at 0z except for N KS/S NE. Cap isn't an issue along the dryline in S KS. What this means to me is that, given forcing, the action would start in N OK/S KS and gradually work north. Edited April 27, 2022 by ClicheVortex2014 1 Link to comment Share on other sites More sharing options...
Cincysnow Posted April 27, 2022 Share Posted April 27, 2022 37 minutes ago, Ingyball said: I know on wxdicso they had some of our lingo underlined that gave a brief description, that could be a good thing to add. @Uscg Ast Otherwise I'll try to make it a point to at least spell out the abbreviations going forward. No worries, wasn’t directed at you, just thought others (as well as me) could find the site useful. And yes, I do remember the other site having a brief description of terminology. 1 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 (edited) 1 hour ago, Cincysnow said: No worries, wasn’t directed at you, just thought others (as well as me) could find the site useful. And yes, I do remember the other site having a brief description of terminology. fwiw, I'm always happy to try to answer questions, too. In the thread or via pm. I began learning by shamelessly asking questions. A goal of mine has been to pay it forward. Edited April 27, 2022 by ClicheVortex2014 2 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 (edited) GFS has been ridiculously consistent. Not much of significance has changed. Here's an area average sounding for SE KS. Pretty nasty. Edited April 27, 2022 by ClicheVortex2014 1 1 Link to comment Share on other sites More sharing options...
Admin Sentinel Posted April 27, 2022 Admin Share Posted April 27, 2022 1 hour ago, Ingyball said: I know on wxdicso they had some of our lingo underlined that gave a brief description, that could be a good thing to add. @Uscg Ast Otherwise I'll try to make it a point to at least spell out the abbreviations going forward. Will definitely work on this with the crew 2 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 Wish there was a better way to compare mlcape with mlcin but this really fares well with previous Euro runs... 21z capped, 0z uncapped. Opposite of GFS. Another way to look at it is that both models have a window for uninhibited instability. 1 Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 Day 3 enhanced. Also decent sized hatched severe threat. DAY 3 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 0238 AM CDT WED APR 27 2022 VALID 291200Z - 301200Z ...THERE IS AN ENHANCED RISK OF SEVERE THUNDERSTORMS ACROSS PARTS OF SOUTHEAST NEBRASKA INTO NORTHEAST KANSAS... ..SUMMARY SEVERE THUNDERSTORMS CAPABLE OF ALL HAZARDS ARE POSSIBLE FRIDAY AFTERNOON INTO FRIDAY NIGHT ACROSS PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS INTO THE LOWER MISSOURI VALLEY. ..SYNOPSIS A NEGATIVE-TILT MID/UPPER TROUGH WILL BE CENTERED FROM THE NORTHERN INTERMOUNTAIN REGION TO THE SOUTHERN ROCKIES FRIDAY MORNING. THIS SYSTEM IS EXPECTED TO SHIFT EAST THROUGH THE PERIOD, EMERGING OVER THE PLAINS BY EVENING. AS THIS OCCURS, AN UPPER LOW IS EXPECTED TO CLOSE OVER THE CENTRAL PLAINS. THIS WILL FOCUS THE STRONGEST FLOW, FORCING FOR ASCENT AND UPPER DIVERGENCE FROM FAR NORTHERN OK INTO KS AND NE. AT THE SURFACE, LOW PRESSURE IS FORECAST TO DEEPEN OVER WESTERN KS AND SHIFT EAST NEAR THE KS/NE BORDER THROUGH EVENING BEFORE LIFTING NORTHEAST TOWARD SOUTHEAST SD OVERNIGHT. A DRYLINE WILL EXTEND SOUTHWARD FROM THE LOW ACROSS CENTRAL KS INTO CENTRAL OK/TX BY MID-AFTERNOON. MEANWHILE, A WARM FRONT WILL LIFT NORTHWARD THROUGH THE PERIOD, EXTENDING FROM THE LOW NEAR CENTRAL NE INTO SOUTHERN IA DURING THE AFTERNOON/EVENING. LOW TO MID 60S F SURFACE DEWPOINTS (WITH SOME POCKETS OF UPPER 60S F POSSIBLE WITH SOUTHWARD EXTENT) WILL RESIDE WITHIN THE WARM SECTOR. A SURFACE COLD FRONT WILL SURGE SOUTHEAST DURING THE EVENING/OVERNIGHT, EVENTUALLY OVERTAKING THE DRYLINE AND BECOMING POSITIONED FROM SOUTHWEST IA INTO WESTERN MO, SOUTHEAST OK AND NORTH-CENTRAL TX BY SATURDAY MORNING. ..NE/KS INTO THE LOWER MO VALLEY FORECAST GUIDANCE INDICATES A STRONG MIDLEVEL CAP WILL ERODE BY LATE AFTERNOON AMID INCREASING ASCENT AND LOW-LEVEL MOIST ADVECTION. BACKED LOW-LEVEL WINDS NEAR THE TRIPLE POINT WILL RESULT IN ENLARGED LOW-LEVEL HODOGRAPHS WITH FORECAST EFFECTIVE SHEAR MAGNITUDES AROUND 35-45 KT. BACKED LOW-LEVEL FLOW WILL ALSO ENHANCE LOW-LEVEL SHEAR, WITH SRH VALUES INCREASING TO GREATER THAN 250 M2/S2. THIS WILL BE FAVORABLE FOR ROTATING SUPERCELLS, AND A FEW TORNADOES ARE POSSIBLE. VERY STEEP MIDLEVEL LAPSE RATES AND MLCAPE AS HIGH AS 2500 J/KG WILL SUPPORT LARGE TO VERY LARGE HAIL. INITIAL SUPERCELL ACTIVITY MAY EVENTUALLY GROW INTO CLUSTERS AS THE COLD FRONT SURGES EAST DURING THE EVENING, RESULTING IN A POTENTIAL TRANSITION TOWARD DAMAGING GUSTS AND HAIL AS CONVECTION SPREADS EAST/NORTHEAST INTO PARTS OF THE MO VALLEY. ..OK/TX A SOMEWHAT MORE CONDITIONAL THREAT WILL EXTEND SOUTHWARD ALONG THE DRYLINE INTO OK/TX. FORCING FOR ASCENT WILL BE WEAKER ACROSS THIS AREA. ADDITIONALLY, GUIDANCE SUGGEST THE STOUT CAPPING INVERSION WILL REMAIN INTACT ACROSS MUCH OF THE AREA THROUGH PEAK HEATING. HOWEVER, A NARROW CORRIDOR ALONG THE DRYLINE APPEARS LIKELY TO BECOME UNCAPPED DURING THE AFTERNOON AMID STRONG HEATING AND INCREASING LOW-LEVEL MOISTURE. IF THESE CELLS DEVELOP, SUPERCELLS CAPABLE OF ALL SEVERE HAZARDS WILL BE POSSIBLE ACROSS PARTS OF CENTRAL OK INTO NORTHWEST TX. AS THE COLD FRONT DEVELOPS SOUTHEAST DURING THE LATE EVENING/OVERNIGHT, ELEVATED STORMS ARE MORE LIKELY TO SHIFT EAST ACROSS THE AREA. THIS ACTIVITY WILL MAINLY POSE A RISK FOR LARGE HAIL. 1 Link to comment Share on other sites More sharing options...
Iceresistance Posted April 27, 2022 Share Posted April 27, 2022 Slight Risks through May 2nd now April 30th - Mississippi & Ohio Rivers May 1st - Western Texas May 2nd - Northern Texas, Southern 2/3rd's of Oklahoma, NW Louisiana, & SW Arkansas 1 Link to comment Share on other sites More sharing options...
ElectricStorm Posted April 27, 2022 Author Share Posted April 27, 2022 Starting to get more concerned for KS on Fri, wouldn't be surprised to see this end up as a 15 hatched moderate risk day. Not excited about anything south of there though. Leaning towards a cap bust in OK for now Link to comment Share on other sites More sharing options...
Iceresistance Posted April 27, 2022 Share Posted April 27, 2022 All the TV Mets I've seen in OKC have Friday as "Severe weather possible, but highly conditional". Link to comment Share on other sites More sharing options...
StormfanaticInd Posted April 27, 2022 Share Posted April 27, 2022 If the cap does break it could indeed get interesting Link to comment Share on other sites More sharing options...
ElectricStorm Posted April 27, 2022 Author Share Posted April 27, 2022 You know the parameters are going to be bonkers when 5/10 and 5/24 both show up in the analogs... I think it will be tough to break the cap in OK but so much can change in a couple days we'll still have to watch it. If anything can break it watch out https://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SP&fhr=F072&rundt=2022042700&map=thbSVR 1 Link to comment Share on other sites More sharing options...
Iceresistance Posted April 27, 2022 Share Posted April 27, 2022 28 minutes ago, OKwx_2001 said: You know the parameters are going to be bonkers when 5/10 and 5/24 both show up in the analogs... I think it will be tough to break the cap in OK but so much can change in a couple days we'll still have to watch it. If anything can break it watch out https://www.eas.slu.edu/CIPS/ANALOG/DFHR.php?reg=SP&fhr=F072&rundt=2022042700&map=thbSVR Most of the models have a stronger cap bias, but only the observed soundings will tell the truth on the Cap strength. Link to comment Share on other sites More sharing options...
Neoncyclone Posted April 27, 2022 Share Posted April 27, 2022 What an absolutely incredible environment the 12 GFS depicts, ridiculous lapse rates to the order of 9.7C in the mid-high levels..... This run features more bad news, I can pull soundings from random places up and down the dryline and see breach-able caps all along. Hope this doesn't become the trend, but the GFS has been incredibly consistent lately, not just for this setup. 21z still a largely uncapped environment, so initiation would almost have to start around that time for any substantial threat to unfold as the cap only strengthens as the night goes on according to the GFS anyways. N OK/S KS border. C OK (still has a pretty strong cap) C KS 1 Link to comment Share on other sites More sharing options...
ElectricStorm Posted April 27, 2022 Author Share Posted April 27, 2022 Slight risk up for today now. Shouldn't be a tornado threat, but could be some gusty winds Link to comment Share on other sites More sharing options...
Meteorologist ClicheVortex2014 Posted April 27, 2022 Meteorologist Share Posted April 27, 2022 (edited) 2 hours ago, Neoncyclone said: What an absolutely incredible environment the 12 GFS depicts, ridiculous lapse rates to the order of 9.7C in the mid-high levels..... This run features more bad news, I can pull soundings from random places up and down the dryline and see breach-able caps all along. Hope this doesn't become the trend, but the GFS has been incredibly consistent lately, not just for this setup. 21z still a largely uncapped environment, so initiation would almost have to start around that time for any substantial threat to unfold as the cap only strengthens as the night goes on according to the GFS anyways. N OK/S KS border. C OK (still has a pretty strong cap) C KS That first one... wow. Even the hail core of a hypothetical supercell in that environment would absolutely wreck a car. Love me a nice dryline. Got a 60 degree dew point gradient on 3km NAM. Edited April 27, 2022 by ClicheVortex2014 1 Link to comment Share on other sites More sharing options...
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