cyclone77 Posted May 6, 2014 Share Posted May 6, 2014 Thursday's setup looks better now with less morning crapvection lingering around though the afternoon. It looks like the best setup though is way west of the sub out in eastern NE, or western Iowa. Eastern Iowa points east will get sloppy seconds as the convection craps out moving into more stable air Thu night. Sunday looks interesting out in southwest Iowa on the Euro. Also the eastern half of Iowa on Monday. However the GFS looks completely different. Link to comment Share on other sites More sharing options...
Hoosier Posted May 6, 2014 Share Posted May 6, 2014 Could have some severe threat here on Friday but instability doesn't look that great (better on the GFS, what do you know) and probably looking at something lower end. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted May 6, 2014 Share Posted May 6, 2014 Instability on the 12z EURO is similar to the 12z GFS. Link to comment Share on other sites More sharing options...
Hoosier Posted May 7, 2014 Share Posted May 7, 2014 Was looking at forecast soundings for tomorrow to see how warm we might get and I couldn't help but notice the very steep mid level lapse rates being progged by the models. In fact, the 00z NAM has 700-500 mb lapse rates in excess of 9 C/km here. Looking at the bigger picture, there's an enormous area with similar lapse rates for tomorrow. My thoughts started to wander and I'm wondering what effect the Central/Western drought may have on severe season in our area. Anyone know of any studies on this subject, like if it could lead to greater capping/enhanced EMLs when the mid level flow originates from that region? Link to comment Share on other sites More sharing options...
IWXwx Posted May 7, 2014 Share Posted May 7, 2014 Was looking at forecast soundings for tomorrow to see how warm we might get and I couldn't help but notice the very steep mid level lapse rates being progged by the models. In fact, the 00z NAM has 700-500 mb lapse rates in excess of 9 C/km here. Looking at the bigger picture, there's an enormous area with similar lapse rates for tomorrow. My thoughts started to wander and I'm wondering what effect the Central/Western drought may have on severe season in our area. Anyone know of any studies on this subject, like if it could lead to greater capping/enhanced EMLs when the mid level flow originates from that region? Interesting thought. Makes sense. If it does enhance capping, it would probably be more pronounced in the western part of the subforum with less of an effect as you go east. Link to comment Share on other sites More sharing options...
Indystorm Posted May 7, 2014 Share Posted May 7, 2014 I would also think it would aid in pushing the dry line farther east when we are able to finally break the cap as has happened in some of our more significant svr wx episodes. Link to comment Share on other sites More sharing options...
Hoosier Posted May 8, 2014 Share Posted May 8, 2014 May 8-9 severe thread http://www.americanwx.com/bb/index.php/topic/43603-may-8-9-severe-weather/ Link to comment Share on other sites More sharing options...
cyclone77 Posted May 8, 2014 Share Posted May 8, 2014 Sunday still looking nice on the Euro for southern Iowa points south and southwest. Monday also still looking decent for the east half of Iowa into IL. GFS starting to trend towards the Euro. 06z is much less progressive than earlier runs. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 8, 2014 Share Posted May 8, 2014 liking garden variety storm chances later this evening...maybe not quite as pathetic/decaying as I thought 12 hours ago Link to comment Share on other sites More sharing options...
Castaway Posted May 8, 2014 Share Posted May 8, 2014 Hope so Alek. Some interval clearing at the very least would be nice Link to comment Share on other sites More sharing options...
Hoosier Posted May 8, 2014 Share Posted May 8, 2014 Sunday still looking nice on the Euro for southern Iowa points south and southwest. Monday also still looking decent for the east half of Iowa into IL. GFS starting to trend towards the Euro. 06z is much less progressive than earlier runs. Sunday looks interesting on the NAM farther east too. Only one problem...it's the NAM. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 8, 2014 Share Posted May 8, 2014 Sunday looks interesting on the NAM farther east too. Only one problem...it's the NAM. Everything still looks pretty good for both days on the 12z Euro. Monday looks really nice for Iowa and southern MN conditionally of course. If those areas are able to destabilize it could be a pretty interesting day in those areas. Love the way that mid-upper levels look. Link to comment Share on other sites More sharing options...
Chicago Storm Posted May 8, 2014 Author Share Posted May 8, 2014 18z GFS was a decent bit slower...and another step towards the ECMWF. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 9, 2014 Share Posted May 9, 2014 Per 00z GFS southern Iowa on Sunday definitely looking interesting with the backed surface winds and nice 50kt+ H5 jet moving in later in the day. The GFS and NAM show the cold front undercutting things pretty quickly across Kansas later in the day. This would indicate the best tor threat would be up over southern Iowa/northern Missouri associated with the warm front/nose of best instability/theta-e. The other area would be down in Oklahoma along the dry line, and away from the surging Kansas cold front. Of course the Euro has been saying no to the idea of a crashing cold front through Kansas on Sunday, which opens up the whole area from southern NE/southwest IA down into OK for good tor threat. I'd lean towards the Euro at this point personally. The GFS has already been trending towards it the last few days, and probably will continue. The 00z GFS also continues to trend towards a less progressive solution for Monday, much like the Euro. Still not as slow as the Euro, but trends may continue. Either way it looks like Monday should be very nice over Iowa/Minnesota. Nicely timed 60-80kt H5 jet rounds the base of the trough and kicks things off in a big way if instability cooperates lol. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 12, 2014 Share Posted May 12, 2014 after another brutal week, looks like a legit shot at some prolonged warmth Link to comment Share on other sites More sharing options...
Hoosier Posted May 12, 2014 Share Posted May 12, 2014 after another brutal week, looks like a legit shot at some prolonged warmth Not sure if you meant to post this in the long range spring thread, but anyway, it appears like the pattern may turn more favorable for severe prospects again during that time. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 18, 2014 Share Posted May 18, 2014 Tuesday looks semi-interesting for the eastern half of Iowa into northern IL/southern WI. Low-level shear is horrific, but the mid-levels are nice, with 40-45kts H5 blowing west to east overhead. 12z GFS maintains a stout cap, but the 00z Euro and the 12z NAM errode it enough to ignite a complex of storms over central Iowa. Decent bulk shear should allow for organization into some sort of a linear MCS. Both the Euro and NAM show cape building to over 2000j/kg ahead of the developing complex. Tor threat looks about nil, but a damaging wind event could develop wherever this ends up setting up. Link to comment Share on other sites More sharing options...
Hoosier Posted May 18, 2014 Share Posted May 18, 2014 5% risk area outlined for Tuesday. Instability looks pretty good (nothing crazy for this time of year) but SPC thinks the models may be overdoing low level moisture. Link to comment Share on other sites More sharing options...
IWXwx Posted May 18, 2014 Share Posted May 18, 2014 5% risk area outlined for Tuesday. Instability looks pretty good (nothing crazy for this time of year) but SPC thinks the models may be overdoing low level moisture. No facts to back this up, but it seems that it is a model bias for this area in the late spring. Link to comment Share on other sites More sharing options...
Hoosier Posted May 18, 2014 Share Posted May 18, 2014 No facts to back this up, but it seems that it is a model bias for this area in the late spring. Anectodally I'd agree, though it seems to become less of an issue toward the end of spring and into summer imo...the exception being if there's a deep drought. Models generally showing a large area of 65+ degree dewpoints in the area on Tuesday. There are dewpoints in the 60s right now in parts of TX. My opinion doesn't matter as much but if the models are off I don't think it will be by much...like I don't think we'll be talking about 8-10 degree errors. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 19, 2014 Share Posted May 19, 2014 18z NAM looks pretty darn good for some solid severe weather Tuesday evening Link to comment Share on other sites More sharing options...
snowlover2 Posted May 19, 2014 Share Posted May 19, 2014 New day 3 outlook for Wednesday has a slight risk area for a good chunk of the OV. DAY 3 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK0206 AM CDT MON MAY 19 2014VALID 211200Z - 221200Z...THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE OH VALLEY ANDPORTIONS OF THE MID MS VALLEY......THERE IS A SLGT RISK OF SVR TSTMS ACROSS THE CENTRAL HIGHPLAINS......SUMMARY...SCATTERED THUNDERSTORMS...POSSIBLY SEVERE...ARE EXPECTED TO DEVELOPACROSS THE OH VALLEY AND OVER PORTIONS OF THE CENTRAL HIGH PLAINS....OH VALLEY/MID MS VALLEY...RIDGE-TOPPING SHORT-WAVE TROUGH IS EXPECTED TO DIG SEWD ACROSS THEUPPER GREAT LAKES REGION INTO THE OH VALLEY DURING THE LATTER HALFOF THE PERIOD. WHILE STRONGEST MID-LEVEL HEIGHT FALLS/ASCENT SHOULDSPREAD ACROSS MI/NRN OH/PA...FRONTAL CONVERGENCE ALONG WIND SHIFTTRAILING ACROSS THE OH VALLEY INTO MO SHOULD PROVE ADEQUATE FOR TSTMDEVELOPMENT BY MID-AFTERNOON. TRUE MARITIME TROPICAL AIRMASS WILLSTRUGGLE TO ADVANCE INLAND OVER THE NEXT FEW DAYS BUT MODELSCONTINUE TO INSIST A CORRIDOR OF RELATIVELY HIGH PW...1.25INCH...WILL EXTEND ALONG/AHEAD OF COLD FRONT PRIOR TO CONVECTIVEDEVELOPMENT. STRENGTHENING NWLY FLOW THROUGH A DEEP LAYER WILLPROVIDE MORE THAN ADEQUATE SHEAR FOR MAINTENANCE OF ORGANIZEDTHUNDERSTORMS. HAVE INTRODUCED 15 PERCENT SEVERE PROBS TO ACCOUNTFOR HAIL/WIND WITH DAYTIME CONVECTION....CENTRAL HIGH PLAINS...UPPER LOW IS EXPECTED TO DRIFT SWD ACROSS THE GREAT BASIN TO APOSITION OVER SRN NV BY 22/12Z. A BELT OF STRONGER FLOW ALOFT WILLEXTEND ACROSS NRN MEXICO THROUGH THE SRN ROCKIES INTO THE CNTRL HIGHPLAINS OF CO WHERE POST-FRONTAL CONVECTION IS EXPECTED TO EVOLVEWITHIN UPSLOPE ELY FLOW. IF LOWER 50S SFC DEW POINTS HOLD ACROSSNERN CO IT APPEARS SIGNIFICANT INSTABILITY MAY BE IN PLACE PRIOR TOCONVECTIVE INITIATION. NAM FORECAST SOUNDING FOR LIC AT 21ZEXHIBITS SBCAPE ON THE ORDER OF 2500 J/KG WITH VERTICAL SHEARSTRONGLY SUPPORTIVE OF SUPERCELLS. FORECAST TEMPERATURE/DEW POINTSPREADS OF 20F OR LESS SUGGEST A TORNADO THREAT WILL ACCOMPANYSUPERCELLS THAT DEVELOP NORTH OF THE FRONT...IN ADDITION TO LARGEHAIL...DARROW.. 05/19/2014 Link to comment Share on other sites More sharing options...
Hoosier Posted May 19, 2014 Share Posted May 19, 2014 Models haven't backed off on dewpoints yet for tomorrow. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 19, 2014 Share Posted May 19, 2014 Models haven't backed off on dewpoints yet for tomorrow. i'd knock em down a point or two but they should be adequate for some high-end garden variety / low end severe i'd lock this in Link to comment Share on other sites More sharing options...
Stebo Posted May 19, 2014 Share Posted May 19, 2014 i'd knock em down a point or two but they should be adequate for some high-end garden variety / low end severe i'd lock this in Perfect for here too, would love storms to end my shift and then drive out to the lake after work to watch the light show. Link to comment Share on other sites More sharing options...
Hoosier Posted May 19, 2014 Share Posted May 19, 2014 i'd knock em down a point or two but they should be adequate for some high-end garden variety / low end severe i'd lock this in 1 or 2 degrees shouldn't hurt the setup. The thing I'm more concerned about is the rather anemic low level flow, although all bets are off if we get an organized/mature MCS. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 19, 2014 Share Posted May 19, 2014 Yeah the 4km NAM is pretty interesting and convection actually looks fairly discrete at CI before congealing a few hours after. Link to comment Share on other sites More sharing options...
snowlover2 Posted May 19, 2014 Share Posted May 19, 2014 New day 2 makes mention of a possible MCS developing. DAY 2 CONVECTIVE OUTLOOKNWS STORM PREDICTION CENTER NORMAN OK1227 PM CDT MON MAY 19 2014VALID 201200Z - 211200Z...NO SVR TSTM AREAS FORECAST......SUMMARY...ISOLATED SEVERE STORMS MAY DEVELOP ACROSS PARTS OF THE MIDWEST ANDTHE CENTRAL HIGH PLAINS TUESDAY AFTERNOON AND EVENING....SYNOPSIS...A STOUT MID-LEVEL ANTICYCLONE WILL REMAIN ANCHORED OVER THE SRNPLAINS WITH A RIDGE EMANATING NEWD TOWARDS THE GREAT LAKES ANDNORTHEAST. THIS RIDGE WILL BE DISPLACED E AS A SHORTWAVE TROUGHGRADUALLY PROGRESSES EWD ALONG THE N-CNTRL CONUS/S-CNTRL CANADIANBORDER. ATTENDANT SURFACE CYCLONE WILL SIMILARLY TRACK EWD WITH AWEAK COLD FRONT ARCING ACROSS THE UPPER MS VALLEY TO CNTRL HIGHPLAINS ON TUE AFTERNOON. IN THE WEST...AN UPPER-LEVEL TROUGH WILLEVOLVE INTO A CUTOFF LOW OVER CA/NV....MIDWEST...AN INCREASINGLY MOIST AND POTENTIALLY UNSTABLE AIR MASS WILL DEVELOPAHEAD OF THE APPROACHING COLD FRONT AS LOWER TO MIDDLE 60S SURFACEDEW POINTS BECOME ESTABLISHED ACROSS SRN PORTIONS OF WI/LOWER MI ONSWD. ROBUST DIURNAL HEATING SHOULD YIELD MLCAPE REACHING 1500-2500J/KG S/W OF LK MI.LARGE-SCALE ASCENT ALONG THE WEAK COLD FRONT APPEARS NEBULOUS OWINGTO MINIMAL CONVERGENCE ALONG THE BOUNDARY AND THE LLJ REMAININGWELL-DISPLACED TO THE S OVER THE OH VALLEY TO OZARK PLATEAU. THEGLANCING PERIPHERY OF MINIMAL MID-LEVEL HEIGHT FALLS IN RESPONSE TOTHE SHORTWAVE TROUGH ALONG THE INTERNATIONAL BORDER MAY FOSTERSUFFICIENT ASCENT FOR A FEW STORMS TO DEVELOP NEAR THE FRONT ALONGTHE NRN EDGE OF THE EML PLUME/STRONGER CAPPING INVERSION. SHOULDTHIS OCCUR...40-50 KT DEEP-LAYER SHEAR WOULD SUPPORT ORGANIZEDUPDRAFTS CAPABLE OF SEVERE HAIL/WIND...WITH SOME POTENTIAL FORUPSCALE GROWTH INTO AN MCS GIVEN THE DEGREE OF INSTABILITY. BUT WITHLARGE DISCREPANCIES IN GUIDANCE ON IF/WHERE STORMS MAY FORM ALONGWITH SUBTLE FORCING MECHANISMS FOR ASCENT...WILL DEFER TO LATEROUTLOOKS ON A POSSIBLE SLIGHT RISK DELINEATION. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 19, 2014 Share Posted May 19, 2014 The NAM, mostly the new 18z run is the most aggressive with how far south the front gets late tomorrow afternoon/evening when convection takes off. The GFS and the Euro seem to keep it a little further north. Link to comment Share on other sites More sharing options...
Stebo Posted May 19, 2014 Share Posted May 19, 2014 New day 2 makes mention of a possible MCS developing. They also backed off the mention of dew points being too high on the models, basically only thing holding back tomorrow would be location of convective initiation, as it stands I would expect the entire 5% they have currently to be bumped up to 15% for tomorrow. Link to comment Share on other sites More sharing options...
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