OceanStWx Posted May 22, 2011 Share Posted May 22, 2011 you can see CU building in perhaps a convergence zone well ahead of the front over western MO into IA..the moisture return is over central IL in that cloud arc heading north..here 10 degree jumps in dewpoints occur as it moves north this may pop rather soon...new RUC hints at that The HRRR wants to develop convection both along a prefrontal trough and again on the cold front. The prefrontal stuff is going by 18 or 19z. This is not a unreasonable evolution at all. Again, this is not a direct comparison, but 6/5 also featured prefrontal convection that went tornadic while the focus was originally on the cold front back towards Des Moines (which did go on to produce at least a couple tornadoes that I can remember). Link to comment Share on other sites More sharing options...
cyclone77 Posted May 22, 2011 Share Posted May 22, 2011 Nice to wake up to sunny skies and a screaming south wind. The vis that Janet posted clearly shows the line of convergence from eastern Kansas into central Iowa. You can also see where the mid-level jet is punching in where all those mid level clouds are over central and western Iowa. Sure wish the timing of that was a bit later, as things may pop a little sooner than I'd like. The good news is we don't have to worry about leftover crapvection like we many times do around the Mississippi valley. The new SREF looks pretty nice! I'm sort of torn on where to head. All of eastern Iowa looks good to me. Seeing the SREF makes me want to lean towards heading north of I-80. We're probably just gonna head west on I-80 into eastern Iowa and pay very close attention to satellite trends. I think the better chance for somewhat more isolated sups along the line will be a bit further south than the bullseye the SREF's showing, so we'll probably play the middle of the road so to speak. Good luck to everyone chasing today. BTW, VERY nice pics Brett! Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 22, 2011 Share Posted May 22, 2011 The atmosphere should destabilize nicely! Already up to 74, with an expected high of 77, so decent chance that busts and we hit 80, extending our string of non-70s highs. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 22, 2011 Share Posted May 22, 2011 Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 22, 2011 Share Posted May 22, 2011 Last couple of RUCs look quite nice, and they have convection coming through at a prime time for storm intensity (around 22 or 23z). Link to comment Share on other sites More sharing options...
Ian Posted May 22, 2011 Share Posted May 22, 2011 Nice shots from yesterday all. Good luck today. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 22, 2011 Share Posted May 22, 2011 That stuff firing up over central Illinois looks enticing. We're about to head out towards the area west of Iowa City and get just ahead of the developing convergence zone. We can go either north or south from there depending on what takes shape... Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 22, 2011 Share Posted May 22, 2011 That stuff firing up over central Illinois looks enticing. We're about to head out towards the area west of Iowa City and get just ahead of the developing convergence zone. We can go either north or south from there depending on what takes shape... The COD team is heading to Iowa city. I prefer staying on the IL side. Link to comment Share on other sites More sharing options...
k*** Posted May 22, 2011 Share Posted May 22, 2011 topeka has been updating the reading page...no official report yet but there's a lot of photos...nothing indicating a violent tornado yet http://www.crh.noaa.gov/news/display_cmsstory.php?wfo=top&storyid=68561&source=0 Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 22, 2011 Share Posted May 22, 2011 I'm so glad I don't have to make a chasing location decision. It would be difficult with a lot of convection firing up at once to decide where to go. If I did, I would choose to go a bit SW of here, maybe around Beloit, Janesville or Rockford. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 22, 2011 Share Posted May 22, 2011 pretty early Link to comment Share on other sites More sharing options...
JoMo Posted May 22, 2011 Share Posted May 22, 2011 Loaded gun. Even as far south as SW MO, conditions are very unstable already. HRRR says I'll be on the very southern end of the system. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 22, 2011 Share Posted May 22, 2011 looks like the confluent zone/ pre-frontal trof is at about from ALO to OTM in eastern IA. I like the eastern half of the MD area as the western half already has slightly veered sfc flow. Link to comment Share on other sites More sharing options...
Indystorm Posted May 22, 2011 Share Posted May 22, 2011 Hey, everyone. Do you remember the high risk for WI and northern IL that busted earlier this year? I think I remember reading that the reason storms weren't more intense and prolific than forecast was because of a lack of a prefrontal trough. Well, we have a prefrontal trough today. And I have meetings later this afternoon and evening in LaPorte and Plymouth and will have to wait till I get home to catch up on how things went. Link to comment Share on other sites More sharing options...
TimChgo9 Posted May 22, 2011 Share Posted May 22, 2011 Wondering if they will pop a watch for us earlier than expected. NIce day outside so far. 79 here now, with S winds at 10-15mph. Dewpoint is 56 but it's climbing. Getting the camera and video camera ready... Hopefully I can get some decent pics... Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 22, 2011 Share Posted May 22, 2011 Wondering if they will pop a watch for us earlier than expected. NIce day outside so far. 79 here now, with S winds at 10-15mph. Dewpoint is 56 but it's climbing. Getting the camera and video camera ready... Hopefully I can get some decent pics... I think they will. Many of the short term models pop storms in South Central Wisconsin and North Central Illinois around 19 or 20z, earlier than MKX is expecting for sure. Link to comment Share on other sites More sharing options...
huronicane Posted May 22, 2011 Share Posted May 22, 2011 DTX to launch 18z sounding. AREA FORECAST DISCUSSIONNATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 1143 AM EDT SUN MAY 22 2011 .UPDATE... THE SHORTWAVE WHICH TRIGGERED EARLY MORNING CONVECTION HAS PULLED OFF TO THE NORTHEAST...LEAVING SOUTHEAST MICHIGAN IN THE SUBSIDENCE WAKE...LEADING TO SUNSHINE AND TEMPERATURES WELL INTO THE 70S...AS OF 11 AM. THE MAIN QUESTION IS HOW MUCH WARMING/DRYING HAS OCCURRED IN THE MID LEVELS...BECAUSE BASED OFF OUR 12Z DTX SOUNDING...MID 80S FOR HIGHS WITH MID 60 DEW PTS WILL SUPPORT CAPES OF 2500-3000 J/KG WITH NO CAP. THESE VALUES ARE SUPPORTED BY 12Z NAM. IF THERE WAS ONLY MARGINAL WARMING IN THE MID LEVEL (PROBABLY LAUNCH 18Z SOUNDING TO HELP PROVIDE SOME ANSWERS)...WOULD EXPECT THE LOW LEVEL BACKED FLOW/LAKE BREEZES BE SUFFICIENT TO FIRE UP A CELL OR TWO...WITH OUTFLOW BOUNDARIES LIKELY SUFFICIENT TO PRODUCE ADDITIONAL CELLS. HAVE TO WATCH REMNANT OUTFLOW BOUNDARY FROM NORTHERN INDIANA...ALONG WITH LAKE MICHIGAN BREEZE LATE IN THE DAY AS WELL. Link to comment Share on other sites More sharing options...
huronicane Posted May 22, 2011 Share Posted May 22, 2011 Very likely overdone, but SPC Mesoanalysis showing >9500J/kg SBCAPE between MAF and SJT. Link to comment Share on other sites More sharing options...
LocoAko Posted May 22, 2011 Share Posted May 22, 2011 1630Z SPC Update: DAY 1 CONVECTIVE OUTLOOK NWS STORM PREDICTION CENTER NORMAN OK 1117 AM CDT SUN MAY 22 2011 VALID 221630Z - 231200Z ...THERE IS A MDT RISK OF SVR TSTMS OVER SERN MN...ERN IA...PARTS OF WI/IL/MO...NERN OK AND NWRN AR... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE GREAT LAKES INTO THE SRN PLAINS... ...UPPER GREAT LAKES INTO THE MID MS AND OH VALLEYS... DEEP-LAYER CYCLONE OVER ERN SD WILL TRANSLATE EWD INTO THE UPPER MS VALLEY BY THIS EVENING WITH AN ASSOCIATED 50-60 KT MIDLEVEL JET STREAK OVERSPREADING THE UPPER MIDWEST THROUGH THE PEAK OF THE DIURNAL HEATING CYCLE. SURFACE CYCLONE WILL ACCORDINGLY DEVELOP EWD TO CNTRL MN BY 23/00Z WITH ASSOCIATED WARM FRONT RAPIDLY LIFTING NWD THROUGH ERN IA/IL INTO WI AND LOWER MI TODAY. HEIGHT FALLS/DYNAMIC FORCING FOR ASCENT ATTENDANT TO MIDLEVEL SYSTEM COUPLED WITH FRONTAL UPLIFT WILL FOSTER SCATTERED SVR TSTMS BY EARLY AFTERNOON INITIALLY FROM PORTIONS OF E-CNTRL/SERN MN AND ERN IA/NERN MO INTO WI/IL. THE COMBINATION OF A MOIST...MODERATELY TO STRONGLY UNSTABLE AIR MASS --I.E. MLCAPE RANGING FROM 1000-1500 J/KG OVER MN/WI TO 2000-3000 J/KG ACROSS MO/IL-- COUPLED WITH 40-50 KT DEEP-LAYER SHEAR ORIENTED ORTHOGONAL TO SURFACE FRONT WILL YIELD A BAND OF SUPERCELLS CAPABLE OF TORNADOES...LARGE HAIL AND DAMAGING WINDS. THE GREATEST TORNADO POTENTIAL --SOME POTENTIALLY SIGNIFICANT-- APPEARS TO BE ACROSS CNTRL/SRN WI INTO IL THIS AFTERNOON AND EVENING WHERE LOW-LEVEL SHEAR WILL BE ENHANCED BY A GRADUALLY STRENGTHENING LLJ. STORMS MAY GROW UPSCALE INTO A QLCS TONIGHT WITH A CONTINUED THREAT FOR MAINLY HAIL AND DAMAGING WIND GUSTS SPREADING EWD THROUGH LOWER MI AND THE OH VALLEY. FOR ADDITIONAL NEAR TERM GUIDANCE...SEE MCD 849. ...SRN PLAINS... 12Z REGIONAL SOUNDINGS SHOWED THE POTENTIAL FOR EXPLOSIVE TSTM DEVELOPMENT LATER TODAY WITH A VERY MOIST BOUNDARY LAYER BENEATH STEEP MIDLEVEL LAPSE RATES...RESULTING IN MLCAPE OF 3000-4000 J/KG. GIVEN THAT LARGE-SCALE FORCING FOR ASCENT WILL REMAIN NEGLIGIBLE THROUGH THE DIURNAL HEATING CYCLE...THE PRIMARY UNCERTAINTIES ARE LOCATION AND EVENTUAL COVERAGE OF SEVERE STORMS. DRYLINE LOCATED FROM WRN OK INTO W-CNTRL AND SWRN TX AS OF MID MORNING WILL MIX MOST RAPIDLY EWD TODAY ACROSS NRN HALF OF OK WITH THE BOUNDARY EXTENDING FROM E OF THE I-44 CORRIDOR INTO W-CNTRL TX BY MID/LATE AFTERNOON. CURRENTLY THE HIGHEST PROBABILITY FOR DIURNAL TSTM DEVELOPMENT APPEARS TO BE FROM NERN OK NEWD INTO MO WHERE AREA WILL BE INFLUENCED BY LEFT EXIT REGION OF UPPER JET STREAK STRETCHING FROM THE SRN ROCKIES INTO SRN PLAINS. HOWEVER...GIVEN THE POTENTIAL FOR STRONG HEATING W OF DRYLINE AND A BREAKABLE CAP /SEE 12Z FWD SOUNDING/...ISOLATED SEVERE STORMS WILL BE POSSIBLE ALONG THE LENGTH OF THE DRYLINE. LATEST MODEL GUIDANCE SUGGESTS DEEPER PBL MIXING MAY LEAD TO DECREASING LOW-LEVEL MOISTURE CONTENT THIS AFTERNOON...LARGELY ACROSS PORTIONS OF CNTRL/ERN TX. WHILE THIS MAY TEMPER THE DEGREE OF INSTABILITY...EXPECT AFTERNOON MLCAPE VALUES OF 3000-4000+ J/KG. WHEN COUPLED WITH 35-40 KT OF DEEP WLY SHEAR...SETUP WILL FAVOR THE DEVELOPMENT OF SUPERCELLS WITH VERY LARGE HAIL BEING THE PRIMARY HAZARD. THE TORNADO THREAT WILL INCREASE IN THE 23/00-03Z TIME PERIOD AS A STRENGTHENING SLY LLJ ENHANCES LOW-LEVEL SHEAR. ...LOWER MS/TN VALLEYS INTO SRN APPALACHIANS... REGENERATIVE TSTM DEVELOPMENT IS OCCURRING THIS MORNING ACROSS AR WITHIN A ZONE OF LOW-LEVEL WAA ASSOCIATED WITH A SWLY LLJ ORIGINATING OVER SRN TX. CONTINUED HEATING/DESTABILIZATION ALONG THE SRN/ERN PERIPHERY OF ONGOING STORMS IN CONCERT WITH A GROWING/DEEPENING COLD POOL MAY ALLOW FOR THE DEVELOPMENT OF A FORWARD-PROPAGATING MCS WITH EMBEDDED SUPERCELLS WHICH WOULD TRACK ACROSS THE TN VALLEY AND NRN GULF COAST STATES WITH ATTENDANT THREATS OF DAMAGING WINDS AND HAIL AND PERHAPS A COUPLE TORNADOES. FOR ADDITIONAL NEAR-TERM GUIDANCE...SEE MCD 850. ...LOWER GREAT LAKES INTO NC... THE EWD PROGRESSION OF A COUPLE OF WEAK MIDLEVEL IMPULSES WILL PROVIDE SUFFICIENT BACKGROUND FORCING TO SUPPORT DIURNAL TSTM DEVELOPMENT WITHIN A WARMING/DESTABILIZING AIR MASS WHERE AFTERNOON MLCAPE WILL RANGE FROM 1000-2000 J/KG OVER NC TO AROUND 500 J/KG ACROSS PORTIONS OF NY/PA. THE STRONGEST VERTICAL SHEAR WILL RESIDE ACROSS THE LOWER GREAT LAKES...DIMINISHING WITH SWD EXTENT. AS SUCH...THE POTENTIAL WILL EXIST FOR A FEW STRONG-MARGINALLY SEVERE STORMS THIS AFTERNOON INTO EVENING WITH THE PRIMARY THREATS BEING HAIL AND LOCALLY STRONG WIND GUSTS. ..MEAD/GRAMS.. 05/22/2011 Link to comment Share on other sites More sharing options...
Srain Posted May 22, 2011 Share Posted May 22, 2011 Welcome to the wild Southern Plains Jake. Link to comment Share on other sites More sharing options...
LocoAko Posted May 22, 2011 Share Posted May 22, 2011 Welcome to the wild Southern Plains Jake. Thanks! Yeah, I'm trying not to clog up your already well-established thread with my own excitement but I don't think I've ever been in 4,500 J/kg of SBCAPE with a LI of -10 before. Wild... It looks like the very best storms may go NE of me here but we will see. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 22, 2011 Share Posted May 22, 2011 Very likely overdone, but SPC Mesoanalysis showing >9500J/kg SBCAPE between MAF and SJT. save that image, as we might never see that again or for a very long time. Link to comment Share on other sites More sharing options...
huronicane Posted May 22, 2011 Share Posted May 22, 2011 save that image, as we might never see that again or for a very long time. Done. Link to comment Share on other sites More sharing options...
Ed Lizard Posted May 22, 2011 Share Posted May 22, 2011 When there is thousands of J/Kg difference between SB and mixed CAPE, I suspect the ML number is better indicator. Oh, the other day the 7 am CRP sounding was something lke 5600 J/Kg, and nothing happened. Texas, especially South Texas, is the land of wasted CAPE. Link to comment Share on other sites More sharing options...
janetjanet998 Posted May 22, 2011 Share Posted May 22, 2011 everthing looks like a go starting in SE MN near the triple point with a small warm sector wedge near closed off 500mb low, storms will work more SE with time perhaps with several spokes Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 22, 2011 Share Posted May 22, 2011 getting several obs now in southeast IA with dew points between 70-72..and thats without the 10ft corn. Link to comment Share on other sites More sharing options...
janetjanet998 Posted May 22, 2011 Share Posted May 22, 2011 TORNADO WATCH NUMBER 322 NWS STORM PREDICTION CENTER NORMAN OK 1210 PM CDT SUN MAY 22 2011 THE NWS STORM PREDICTION CENTER HAS ISSUED A TORNADO WATCH FOR PORTIONS OF NORTHEAST IOWA SOUTHEAST MINNESOTA WESTERN WISCONSIN EFFECTIVE THIS SUNDAY AFTERNOON AND EVENING FROM 1210 PM UNTIL 800 PM CDT. TORNADOES...HAIL TO 2 INCHES IN DIAMETER...THUNDERSTORM WIND GUSTS TO 70 MPH...AND DANGEROUS LIGHTNING ARE POSSIBLE IN THESE AREAS. DISCUSSION...SRN FRINGE OF ELEVATED TSTMS ONGOING ACROSS SERN MN/WRN WI MAY BECOME PROGRESSIVELY SURFACE BASED THIS AFTERNOON OWING TO THE RAPID NWD FLUX OF 60+ F DEWPOINTS ALONG AND S OF WARM FRONT. ADDITIONAL STORM DEVELOPMENT WILL BE POSSIBLE ALONG WARM AND COLD FRONTS ASSOCIATED WITH SURFACE LOW MOVING FROM E-CNTRL SD TOWARD CNTRL MN. ENHANCED LOW-LEVEL SHEAR AHEAD OF SURFACE LOW COUPLED WITH THE MOISTENING/DESTABILIZING AIR MASS WILL SUPPORT SUPERCELLS CAPABLE OF LARGE HAIL AND TORNADOES. Link to comment Share on other sites More sharing options...
ZackH Posted May 22, 2011 Share Posted May 22, 2011 Hey, everyone. Do you remember the high risk for WI and northern IL that busted earlier this year? I think I remember reading that the reason storms weren't more intense and prolific than forecast was because of a lack of a prefrontal trough. Well, we have a prefrontal trough today. And I have meetings later this afternoon and evening in LaPorte and Plymouth and will have to wait till I get home to catch up on how things went. That was a moderate not a high and it was still a tornado outbreak. Chased it and it was far from a bust. The moderate easily verified. That was April 10 and that's the only substantial WI threat I remember this year and I know for a fact there wasn't ever a high up there this year. And I'm almost positive that's the only mod WI has had also. Link to comment Share on other sites More sharing options...
Hoosier Posted May 22, 2011 Share Posted May 22, 2011 That was a moderate not a high and it was still a tornado outbreak. Chased it and it was far from a bust. The moderate easily verified. That was April 10 and that's the only substantial WI threat I remember this year and I know for a fact there wasn't ever a high up there this year. Correct. The Illinois portion was fairly quiet but Wisconsin did well. Link to comment Share on other sites More sharing options...
Powerball Posted May 22, 2011 Share Posted May 22, 2011 Things are looking good this way. The cap is nearly non-existant and CAPE is over 2000J/KG with moisture advection continuing. There's quite a bit of dry air above 900mb though, that and the lack of a defined trigger scares me. Based on 850mb temps of 17*C and full sunshine we should make it to the mid 80s, we'll see. Link to comment Share on other sites More sharing options...
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