Quincy Posted June 24, 2015 Share Posted June 24, 2015 Here's the latest update I've been working on: A severe thunderstorm and isolated tornado threat exists across portions of the middle Mississippi River Valley late this afternoon into the early evening hours. While severe thunderstorms with large hail and damaging winds will be the primary threats, there is a conditional risk for a few tornadoes. The elevated focus area is across southeastern Iowa into far northeastern Missouri and portions of west-central Illinois. Other severe thunderstorms are expected surrounding the conditional threat zone with a tornado threat in the larger surrounding yellow shading as well. Convection was ongoing across much of Iowa at 2 p.m. CDT. A quasi-stationary front was draped from near the Nebraska/Iowa/Missouri tri-state border, southeastward into northern Missouri and west-central Illinois. To the southwest of the front, strong instability in excess of 3000 J/kg MLCAPE was observed via mesoanalysis across much of Missouri, eastern Kansas and far southeastern Nebraska. This warm sector should gradually spread northeast with time. Near the frontal boundary, 20-30 knots of 0-1km shear was noted, with 50+ knots of bulk shear and 0-1km SRH of 150-250 m2/s2. This is a complex setup, but the region on the southern flank of ongoing convection and to the immediate south is where the greatest tornado threat exists. The area near the Missouri/Iowa border should remain capped for most of the afternoon, but there is a conditional threat for supercells to develop late this afternoon into the early evening hours across south-central to southeastern Iowa. Any storms that remain discrete could take advantage of an inflow environment characterized with moderate to strong instability and sufficient low level shear to potentially form a few tornadoes. High resolution convection-allowing models have showed little consistency in timing, storm mode and coverage of such convection. Nonetheless, the threat exists and there is a small window for a strong tornado, if such a storm were to develop and remain isolated. Look for this potential activity to spread east-southeast to southeast into the evening. The ongoing convection may begin to strengthen somewhat over the eastern half of Iowa and eventually northwestern Illinois. This will pose a threat for mainly large hail. There is a greater probability that more widespread convection develops into the evening hours as the low level jet increases and the environment, at least elevated, becomes more unstable with northeast extent. The evening threat looks to be predominantly strong winds, although some large hail will be possible. This should develop near to just north of I-80 in eastern Iowa and spread into northwestern Illinois. Upscale growth may result in a significant MCS forming from this activity as it spreads into northern and central Illinois. This MCS threat should remain south of Chicago, but may spread as far east as portions of Indiana overnight. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted June 24, 2015 Share Posted June 24, 2015 The heavier convection with the current Iowa MCS should remain south of CR and get IC and points just south. Just a general rain here The HRRR, over the last several runs, has gradually shifted tonight's development south from hw20 to hw30. Link to comment Share on other sites More sharing options...
JasonOH Posted June 24, 2015 Share Posted June 24, 2015 MCD just got out out MESOSCALE DISCUSSION 1157 NWS STORM PREDICTION CENTER NORMAN OK 0223 PM CDT WED JUN 24 2015 AREAS AFFECTED...SWRN IA...FAR NWRN MO AND SERN NEB CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 241923Z - 242130Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...WE ARE MONITORING AN AREA ACROSS SWRN IA AND VICINITY FOR A CONDITIONAL TORNADO AND SIG HAIL THREAT. DISCUSSION...VISIBLE IMAGERY SHOWS TWO OUTFLOW BOUNDARIES INTERSECTING NEAR THE MO RIVER FROM SERN NEB INTO SWRN IA WHERE STRONG HEATING WILL CONTINUE TO ERODE THE CAPPING INVERSION THIS AFTERNOON. MEANWHILE UPSTREAM...DEWPOINTS REMAIN NEAR 70 F WHICH WHEN COMBINED WITH FURTHER HEATING WILL YIELD VERY STRONG INSTABILITY. WIND PROFILES NEAR THESE OUTFLOW BOUNDARIES ARE QUITE FAVORABLE FOR BOTH SUPERCELLS AND TORNADOES. DESPITE MOST MODEL GUIDANCE TO THE CONTRARY...AN ISOLATED SUPERCELL OR TWO CANNOT BE RULED OUT BY LATE AFTERNOON IN THIS GENERAL VICINITY...ALTHOUGH PERHAPS DISPLACED A BIT FARTHER NEWD TOWARD EVENING AS THE WARM FRONT DEVELOPS. IF CU FIELDS NEAR THE BOUNDARY CAN SUSTAIN THROUGH LATE AFTERNOON...A WATCH MAY BE NEEDED. ..JEWELL/GUYER.. 06/24/2015 ATTN...WFO...DMX...EAX...OAX... Link to comment Share on other sites More sharing options...
Natester Posted June 24, 2015 Share Posted June 24, 2015 Makes me wonder if the next outlook will have the enhanced risk shifted somewhat south? It wouldn't surprise me considering that the warm front hasn't made much progress today. Hopefully I don't jinx it. Link to comment Share on other sites More sharing options...
A-L-E-K Posted June 24, 2015 Share Posted June 24, 2015 IA complex crapping the bed as it attempts to push into an unfavorable atmosphere Link to comment Share on other sites More sharing options...
homedis Posted June 24, 2015 Share Posted June 24, 2015 IA complex crapping the bed as it attempts to push into an unfavorable atmosphere Yep. Disorganized mess of heavy rain. Link to comment Share on other sites More sharing options...
Santa Clause Posted June 24, 2015 Share Posted June 24, 2015 Think the ENH will be dropped south or just eliminated? Certainly has been an extremely difficult year to pin anything down. Link to comment Share on other sites More sharing options...
Natester Posted June 24, 2015 Share Posted June 24, 2015 Yep. Disorganized mess of heavy rain. And there's more backbuilding going on. Link to comment Share on other sites More sharing options...
Quincy Posted June 24, 2015 Share Posted June 24, 2015 Think the ENH will be dropped south or just eliminated? Certainly has been an extremely difficult year to pin anything down.They'll definitely maintain ENH. Might even see a 10% tor somewhere in southeastern Iowa/vicinity. Link to comment Share on other sites More sharing options...
Central Illinois Posted June 24, 2015 Share Posted June 24, 2015 Here's the latest update I've been working on nice write up thanks for sharing appreciate itSent from my iPhone 6 using Tapatalk Link to comment Share on other sites More sharing options...
RyanDe680 Posted June 24, 2015 Share Posted June 24, 2015 Makes me wonder if the next outlook will have the enhanced risk shifted somewhat south? It wouldn't surprise me considering that the warm front hasn't made much progress today. Hopefully I don't jinx it. It should have a while ago Link to comment Share on other sites More sharing options...
RyanDe680 Posted June 24, 2015 Share Posted June 24, 2015 nice write up thanks for sharing appreciate it Sent from my iPhone 6 +1 Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 MESOSCALE DISCUSSION 1157NWS STORM PREDICTION CENTER NORMAN OK0223 PM CDT WED JUN 24 2015AREAS AFFECTED...SWRN IA...FAR NWRN MO AND SERN NEBCONCERNING...SEVERE POTENTIAL...WATCH POSSIBLEVALID 241923Z - 242130ZPROBABILITY OF WATCH ISSUANCE...40 PERCENTSUMMARY...WE ARE MONITORING AN AREA ACROSS SWRN IA AND VICINITY FORA CONDITIONAL TORNADO AND SIG HAIL THREAT.DISCUSSION...VISIBLE IMAGERY SHOWS TWO OUTFLOW BOUNDARIESINTERSECTING NEAR THE MO RIVER FROM SERN NEB INTO SWRN IA WHERESTRONG HEATING WILL CONTINUE TO ERODE THE CAPPING INVERSION THISAFTERNOON. MEANWHILE UPSTREAM...DEWPOINTS REMAIN NEAR 70 F WHICHWHEN COMBINED WITH FURTHER HEATING WILL YIELD VERY STRONGINSTABILITY.WIND PROFILES NEAR THESE OUTFLOW BOUNDARIES ARE QUITE FAVORABLE FORBOTH SUPERCELLS AND TORNADOES. DESPITE MOST MODEL GUIDANCE TO THECONTRARY...AN ISOLATED SUPERCELL OR TWO CANNOT BE RULED OUT BY LATEAFTERNOON IN THIS GENERAL VICINITY...ALTHOUGH PERHAPS DISPLACED ABIT FARTHER NEWD TOWARD EVENING AS THE WARM FRONT DEVELOPS. IF CUFIELDS NEAR THE BOUNDARY CAN SUSTAIN THROUGH LATE AFTERNOON...AWATCH MAY BE NEEDED...JEWELL/GUYER.. 06/24/2015 Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted June 24, 2015 Share Posted June 24, 2015 Definitely don't see the enhanced area being dropped. Today feel's just like Monday when everyone was writing off the severe potential by mid afternoon. We have plenty of time and the models have been very consistent that the severe weather threat doesn't get going until late this evening and early tonight. Link to comment Share on other sites More sharing options...
Hoosier Posted June 24, 2015 Author Share Posted June 24, 2015 More recent frames of DMX radar showing a bit of sinking southward, at least of the heavier stuff. And as was mentioned above, the bow echo has dramatically weakened. Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 OAX VWP is impressive... And this type of veering wind profile is LIKELY seen across much of that MD area depicted above, and low-level backing might be even more impressive along the actual boundary/WF. Link to comment Share on other sites More sharing options...
homedis Posted June 24, 2015 Share Posted June 24, 2015 Definitely don't see the enhanced area being dropped. Today feel's just like Monday when everyone was writing off the severe potential by mid afternoon. We have plenty of time and the models have been very consistent that the severe weather threat doesn't get going until late this evening and early tonight. Agree 100%. Warm front still has plenty of time to move and everything else also has plenty time to set up. Still think a slight south shift with the enhanced is going to come Edit: Also the current path of the disorganized MCS could tell us about how the convection later on will move, but we still have some time to see when this mess will turn SE. Link to comment Share on other sites More sharing options...
Hoosier Posted June 24, 2015 Author Share Posted June 24, 2015 Count me in on the ENH not being dropped. Could see it shifted south though. Link to comment Share on other sites More sharing options...
Quincy Posted June 24, 2015 Share Posted June 24, 2015 SDA reporting 88/77 and it looks legit. 92/75 at STJ. Link to comment Share on other sites More sharing options...
homedis Posted June 24, 2015 Share Posted June 24, 2015 SPC is late on this one Edit: Updated it... SLIGHTLY south. By slightly I mean VERY slight (like 15 miles south again) Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 ...THERE IS AN ENH RISK OF SVR TSTMS FROM IA THROUGH NRN AND CNTRL IL INTO WRN IND... ...THERE IS A SLGT RISK OF SVR TSTMS FROM THE NRN AND CNTRL PLAINS THROUGH THE MIDWEST... ...THERE IS A SLGT RISK OF SVR TSTMS OVER A PORTION OF THE SERN STATES... ...THERE IS A MRGL RISK OF SVR TSTMS FROM THE CNTRL AND NRN PLAINS INTO THE MIDWEST... ..THERE IS A MRGL RISK OF SVR TSTMS ..SUMMARY A SEVERE THREAT IS EXPECTED FROM PARTS OF THE NORTHERN PLAINS EAST SOUTHEASTWARD INTO THE MIDWEST MAINLY LATE THIS AFTERNOON AND EVENING. LARGE HAIL AND DAMAGING WIND GUSTS ALONG WITH A THREAT FOR A FEW TORNADOES WILL BE POSSIBLE. A CONCENTRATED AREA OF SEVERE STRAIGHT-LINE WINDS MAY OCCUR ACROSS IOWA INTO PORTIONS OF NORTHERN/CENTRAL ILLINOIS THIS EVENING AND OVERNIGHT. ..IA THROUGH NRN MO INTO NRN AND CNTRL IL AND WRN IND HAVE MADE ONLY MODEST ADJUSTMENTS TO CURRENT FORECAST. VISIBLE AND OBJECTIVE ANALYSIS DATA SHOW A CONVECTIVELY ENHANCED BOUNDARY FROM SERN MO NWWD THROUGH SERN NEB. AN MCS CONTINUES EAST WELL NORTH OF THIS FEATURE THROUGH IA. HOWEVER...CLEARING SOUTH OF THE MCS IS CONTRIBUTING TO DESTABILIZATION OF THE SFC LAYER NORTH OF THE BOUNDARY FROM SERN NEB...NRN MO INTO SRN IA WHERE LATEST OBJECTIVE ANALYSIS SHOWS 1500-3000 J/KG MLCAPE...BUT THE ATMOSPHERE REMAINS CAPPED. CURRENT INDICATIONS ARE THAT ADDITIONAL STORMS MAY DEVELOP THIS AFTERNOON INTO EARLY EVENING ALONG THE SRN PERIPHERY OF THE MCS SUPPORTED BY FURTHER DIABATIC WARMING OF THE BOUNDARY LAYER AND FORCING ASSOCIATED WITH PROGRESSIVE MCV. SHOULD STORMS DEVELOP VWP DATA SHOW STRONG DEEP SHEAR AND LARGE HODOGRAPHS IN THIS REGION WHERE LOW-LEVEL WINDS REMAIN BACKED TO SLY OR SELY NORTH OF THE OUTFLOW BOUNDARY. SHOULD STORMS DEVELOP THIS EVENING...SUPERCELLS WILL BE LIKELY WITH A THREAT FOR A FEW TORNADOES...VERY LARGE HAIL AND DAMAGING WIND. ADDITIONAL STORMS ARE EXPECTED OVERNIGHT ACROSS IA AS STRENGTHENING LLJ INTERACTS WITH THE PRE-EXISTING BAROCLINIC ZONE. WHILE INITIAL THREAT MAY BE LARGE HAIL...STORMS MAY EVENTUALLY CONGEAL INTO AN MCS SUPPORTING POTENTIAL FOR A MORE CONCENTRATED ZONE OF DAMAGING WIND. ..DIAL.. 06/24/2015 Link to comment Share on other sites More sharing options...
RyanDe680 Posted June 24, 2015 Share Posted June 24, 2015 Barely any change on the D1... again, still surprising.. Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 Introduced a 10% TOR Prob across southern IA as I figured they might yesterday after things came into focus, and as Quincy analyzed earlier as well. Interesting though, since they introduced that given the impressive LLVL wind profile, that they didn't have any mention of a strong tornado too. Link to comment Share on other sites More sharing options...
Natester Posted June 24, 2015 Share Posted June 24, 2015 18z NAM 4k shows initiation along highway 30. Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 18Z HRRR later at 00Z/Thursday across SE IA. Just to give an idea of the environment that will be in place... Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted June 24, 2015 Share Posted June 24, 2015 18z 4 km NAM continues to show several rounds of intense convection moving from Iowa into North Central and Central Illinois and into Indiana. Link to comment Share on other sites More sharing options...
jojo762 Posted June 24, 2015 Share Posted June 24, 2015 18z NAM 4k shows initiation along highway 30. 18Z 4K NAM initialized like trash. Link to comment Share on other sites More sharing options...
Hoosier Posted June 24, 2015 Author Share Posted June 24, 2015 18z 4 km NAM continues to show several rounds of intense convection moving from Iowa into North Central and Central Illinois and into Indiana. Worth mentioning though that it did not initialize the current activity well at all, so its placement for stuff later may be suspect. Link to comment Share on other sites More sharing options...
Quincy Posted June 24, 2015 Share Posted June 24, 2015 20z ESRH: Link to comment Share on other sites More sharing options...
Natester Posted June 24, 2015 Share Posted June 24, 2015 Is the storms in western Iowa the main show or not? Link to comment Share on other sites More sharing options...
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