TheWeatherPimp Posted April 6, 2011 Share Posted April 6, 2011 I think it's a little early to be saying something that bold, especially when you're toward the eastern end of the risk area and especially to EMs. We'll see - came from one of my favorite mets up there. I agree it might be a bit to early, but even their CWA looks to be primed by Sunday Afternoon/Evening. Link to comment Share on other sites More sharing options...
Hoosier Posted April 6, 2011 Share Posted April 6, 2011 I think it's a little early to be saying something that bold, especially when you're toward the eastern end of the risk area and especially to EMs. I was a little surprised at that myself. Seems like we've been watching this for a long time but we're still several days out. Link to comment Share on other sites More sharing options...
Hoosier Posted April 6, 2011 Share Posted April 6, 2011 We'll see - came from one of my favorite mets up there. I agree it might be a bit to early, but even their CWA looks to be primed by Sunday Afternoon/Evening. Sunday night is probably going to be a long night regardless of exactly how this evolves. If we keep a nocturnal tornado threat going, that is bad news. It's hard to assess at this point though given the varying solutions and the likelihood that the models aren't going to handle the boundary layer very well this far out. Link to comment Share on other sites More sharing options...
B-Rent Posted April 6, 2011 Share Posted April 6, 2011 Sunday night is probably going to be a long night regardless of exactly how this evolves. If we keep a nocturnal tornado threat going, that is bad news. It's hard to assess at this point though given the varying solutions and the likelihood that the models aren't going to handle the boundary layer very well this far out. I've learned after living here for 8 years to expect nighttime tornadoes as the rule, not the exception. Sent from my ADR6400L using Tapatalk Link to comment Share on other sites More sharing options...
A-L-E-K Posted April 6, 2011 Share Posted April 6, 2011 Bump. wish i could join you but i have too much office work to catch up on. Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 6, 2011 Share Posted April 6, 2011 MKX already has an 80% chance of storms Sunday night...whether they're severe or not looks to be the major question at this point. Sounds like the GFS is more bullish on our potential this far north. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 6, 2011 Author Share Posted April 6, 2011 18z NAM has more instability along and south of the warm front and a weaker cap but still doesn't break out precip till 3z in central IA once the LLJ increases after dark and the warm front rapidly lifts northward into IA increasing instability. some serious parameters... and a pretty damn impressive wind profile/hodo for around IRK, talk about insane turning from the sfc up to H5 and sitting in a environment with near 4000 j/kg and dew points near 70. Link to comment Share on other sites More sharing options...
csnavywx Posted April 6, 2011 Share Posted April 6, 2011 Yes, though this was the same exact crap it pulled for Sunday's storms as well. Too much solar shielding on the model from the low level cloud layers it produces. Those will mix out into some nice cumulus during the day. It's doing it again with similar conditions, so I would buy a break time 2-3 hours before sunset. Note the 20m 700mb height falls and 10-20m 500mb height falls superimposed over 30-40 1000-500mb thickness rises near extreme SW Iowa. If I had to pick a place it would break, it would be there on this run. Of course, then these storms would run into an extremely favorable environment immediately downstream. Edit: If I had to modify that sounding for something closer to reality, I'd raise the surface temps 4-6C and drop the dews 2-4C. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 6, 2011 Author Share Posted April 6, 2011 Yes, though this was the same exact crap it pulled for Sunday's storms as well. Too much solar shielding on the model from the low level cloud layers it produces. Those will mix out into some nice cumulus during the day. It's doing it again with similar conditions, so I would buy a break time 2-3 hours before sunset. Note the 20m 700mb height falls and 10-20m 500mb height falls superimposed over 30-40 1000-500mb thickness rises near extreme SW Iowa. If I had to pick a place it would break, it would be there on this run. Of course, then these storms would run into an extremely favorable environment immediately downstream. Edit: If I had to modify that sounding for something closer to reality, I'd raise the surface temps 4-6C and drop the dews 2-4C. Agreed, no model had southern IA bumping into the mid-upper 80's last sunday and if something fires in that environment it could be trouble. It's so nice to see backed sfc winds in the warm sector. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 6, 2011 Share Posted April 6, 2011 Got the whole weekend off, so we'll be out there. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 6, 2011 Share Posted April 6, 2011 This will give me something to look at tonight, seeing as evening long term shifts don't have a lot of forecast updates. I already like the look of 0-4 km thetae lapse rates compared to the last couple of events, but it's just a cursory glance at this point. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 6, 2011 Share Posted April 6, 2011 Both of my partners are in. We are planning on leaving early Saturday morning, chasing Saturday Evening in Western Illinois/Northeastern Missouri/Southeastern Iowa area; staying in a hotel in Central Illinois Saturday Night and chasing again across Illinois and Indiana on Sunday. Link to comment Share on other sites More sharing options...
cyclone77 Posted April 6, 2011 Share Posted April 6, 2011 18z NAM has more instability along and south of the warm front and a weaker cap but still doesn't break out precip till 3z in central IA once the LLJ increases after dark and the warm front rapidly lifts northward into IA increasing instability. some serious parameters... and a pretty damn impressive wind profile/hodo for around IRK, talk about insane turning from the sfc up to H5 and sitting in a environment with near 4000 j/kg and dew points near 70. That sounding is beautiful. Love the 30kts just off the surface. Wish we could lock this in now lol. Link to comment Share on other sites More sharing options...
hm8 Posted April 6, 2011 Share Posted April 6, 2011 LOT with a brilliant write up, especially the bolded part EXTENDED FORECAST DISCUSSION... 315 PM CDT... BY SATURDAY...THE NEXT UPSTREAM SYSTEM WILL GATHER STRENGTH. HAVE GENERALLY CONTINUED TO FOLLOW THE ECMWF WHICH REMAINS SLOWER THAN THE OTHER MODELS...PARTICULARLY THE GFS. THIS SYSTEM IS EXPECTED TO DEVELOP A LITTLE FARTHER NORTH THAN THE FIRST SYSTEM...WITH THE MAIN SFC LOW TRACKING INTO THE UPPER MISSISSIPPI VALLEY. THIS WILL ALLOW THE WARM FRONT TO SURGE NORTH...PUTTING THE WHOLE CWA FIRMLY IN WARM SECTOR AIR...WITH TEMPERATURES REACHING INTO THE LOW TO MIDDLE 70S. SATURDAY SHOULD BE A TRANSITION DAY AS THE STRONGEST LOW LEVEL FORCING WILL BE WELL NORTH AND WEST OF THE CWA. THE IS A CHANCE FOR SOME SCATTERED SHOWERS OF THUNDERSTORMS ON SATURDAY AS A WEAK SHORTWAVE RIDES OVER THE BUILDING UPPER RIDGE AS IT MOVES EAST OF THE MISSISSIPPI RIVER. THROUGH SATURDAY EVENING AND INTO SUNDAY...CONVECTIVE POTENTIAL WILL BE ON THE INCREASE AS THE UPPER TROUGH DEEPENS OVER THE ROCKIES. THE ASSOCIATED COLD FRONT WILL STRENGTHEN AS IT SWEEPS ACROSS THE PLAINS. GIVEN THE STRENGTH OF THE FRONT AND THE WARM/MOIST ADVECTION IN THE WARM SECTOR...SEVERE THUNDERSTORMS WILL BE A DISTINCT POSSIBILITY FOR SEVERE THUNDERSTORMS. THE ENVIRONMENT SHOULD BE WELL CAPPED THROUGH MUCH OF THE DAY...BUT AS THE FRONT WORKS EWD...THE CAP SHOULD BREAK AND CONVECTIVE ACTIVITY QUICK TO DEVELOP. AS USUAL...TIMING WILL BE THE QUESTION. AS MENTIONED ABOVE...HAVE BEEN TRENDING TOWARD THE ECMWF...WHICH HAS BEEN ON THE SLOWER SIDE OF THE GUIDANCE ENVELOPE. GIVEN THE LATER ARRIVAL TIME...HAVE ONLY HAD A QUICK OPPORTUNITY TO LOOK AT THE NEW 12Z ECMWF RUN...AND IT IS TRENDING EVEN SLOW AND MORE AMPLIFIED THAN THE ALREADY SLOWER OLD 00Z RUN. IF THIS TREND CONTINUES...THE GREATER THUNDERSTORM AND SEVERE POTENTIAL MAY HOLD OFF UNTIL LATER SUNDAY NIGHT OR EARLY MONDAY. THIS SITUATION WILL BEAR WATCHING OVER THE NEXT FEW DAYS FOR FURTHER FORECAST REFINEMENT. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 6, 2011 Author Share Posted April 6, 2011 LOT with a brilliant write up, especially the bolded part Never been a fan of Krein's AFD's. This was ok IMO. Link to comment Share on other sites More sharing options...
Indystorm Posted April 6, 2011 Share Posted April 6, 2011 Never been a fan of Krein's AFD's. This was ok IMO. Well, baroclinic instability would remind us that this is only because mets are sometimes pressed for time to get these things out and grammatical and other wording mistakes can be made. Link to comment Share on other sites More sharing options...
jdrenken Posted April 7, 2011 Share Posted April 7, 2011 EAX had a book like usual during severe events. MEDIUM RANGE (SATURDAY THROUGH WEDNESDAY)... ...MULTIPLE EPISODES OF SIGNIFICANT SEVERE WEATHER POSSIBLE THIS WEEKEND... ALTHOUGH LITTLE CHANGE IN THE OVERALL PATTERN HAS BEEN NOTED IN OPERATIONAL AND ENSEMBLE MEMBERS THROUGHOUT THE MEDIUM RANGE PERIOD...MINOR DIFFERENCES AND TRENDS IN THE MORE PRECISE TIMING OF SALIENT FEATURES EJECTING THROUGH THE PLAINS ARE QUITE EVIDENT IN THE PAST 12 HOURS. NOT SURPRISINGLY...THE RECENT OPERATIONAL GFS AND MAJORITY OF ITS ENSEMBLE MEMBERS HAVE SLOWED THE PROGRESSION OF DEEP DESERT SOUTHWEST NEGATIVE HEIGHT ANOMALIES INTO THE PLAINS BY ABOUT 6-12 HOURS VERSUS THIS TIME YESTERDAY. THIS MATCHES CLOSER TO THE PREFERRED ECMWF/GEM/GEM ENSEMBLE BLEND PREVIOUSLY TAKEN...AND NOW MORE DETAILS FROM THE 12Z GFS COULD BE UTILIZED FOR THIS FORECAST PACKAGE. BASED ON A MAJORITY APPROACH FROM ALL NAEFS MEMBERS...FEEL THE 00Z ECMWF IS SLIGHTLY TOO DEEP AND TOO FAR SOUTH WITH THE H5 LOW (ALBEIT TIMING GOOD...AND THE MOST RECENT 12Z ECMWF RECTIFYING THIS DISCREPANCY)...WITH THE 12Z OPERATIONAL GEM SLIGHTLY TOO SLOW AND TOO FAR WEST...LEADING TO A FEELING THAT THE 12Z GFS IS NOT A BAD COMPROMISE AT THIS POINT. LARGE SWRN TROUGH WILL BEGIN TO MAKE AN EASTWARD JOG SATURDAY AFTERNOON...AS STRONG 120+KT JET ENERGY TRANSLATES TO THE ERN PERIPHERY OF THE TROUGH AXIS. H5 HEIGHT FALLS WILL START TO CROSS INTO THE PLAINS STATES WITH LEE SFC PRESSURES DEEPENING OVER THE CNTRL HIGH PLAINS...ALLOWING QUALITY DEEP GULF MOISTURE TO SURGE NORTH THROUGHOUT THE WARM SECTOR. IT STILL APPEARS THAT AT LEAST ONE SUBTLE LEAD SHORTWAVE WILL PROPAGATE EAST INTO THE PLAINS AND CROSS THE DRYLINE THROUGH CNTRL KANSAS INTO A REGION OF HIGHLY DIFFLUENT JET FLOW ALOFT. ALTHOUGH MODEL FORECASTS OF NEAR 70 DEGREE SFC DEWPOINTS ARE ALMOST ASSUREDLY OVER INFLATED...STILL FEEL A SOLID 13 G/KG OF WELL MIXED SFC-H8 MOISTURE WILL BE AVAILABLE IN THE WARM SECTOR...YIELDING MLCAPES AOA 2500 J/KG...ALBEIT WITH STILL SOME CINH. DEEP LAYER 0-6 KM AND LOW LEVEL 0-1 KM SHEAR PARAMETERS WILL BE MORE THAN SUFFICIENT FOR SUPERCELLULAR CONVECTION...WITH 0-3 KM SRH APPROACHING 400 M2/S2 SUPPORTING LOW LEVEL ROTATION TO COUPLE WITH ITS MIDLEVEL COUNTERPART. GIVEN THAT DEEP ASCENT IS SUFFICIENT TO BREAK THE REMAINING CAPPING INVERSION BY PEAK HEATING...FEEL MODEL QPF DEPICTION AND THE STORM INITIATION POINT IS LIKELY POSITIONED TOO FAR EAST SATURDAY AFTERNOON (MORE LIKELY BEGINNING IN NORTH CNTRL KANSAS/SOUTH CNTRL NEBRASKA)...THOUGH STORM MOTION VECTORS WOULD BRING ANY SUPERCELLS INTO NERN KANSAS/FAR NWRN MISSOURI BY LATE AFTERNOON/EARLY EVENING...WITH ALL MODES OF SEVERE WEATHER POSSIBLE. ANY ACTIVITY SHOULD MOVE INTO IOWA LATER SATURDAY EVENING WITH THE PASSAGE OF THIS ASSUMED LEAD WAVE. GIVEN THE SLOWER TIMING OF THE H5 WAVE FROM NEW MEXICO EARLY SUNDAY MORNING TO CNTRL KANSAS SUNDAY AFTERNOON...MUCH OF THE FORECAST AREA WOULD BE AT RISK FOR WIDESPREAD SEVERE WEATHER THROUGH EARLY SUNDAY EVENING...AS A DRYLINE PUNCHES EAST INTO FAR WRN MISSOURI JUXTAPOSED WITH FAVORABLY STRONG DYNAMICAL LIFT AND UNSTABLE SFC PARCELS. MODELS ARE CONSISTENT IN INDICATING SLIGHTLY LESS AVAILABLE INSTABILITY SUNDAY AFTERNOON...OWING TO A REDUCTION IN LAPSE RATES ALOFT AND PARTIAL CONTAMINATION OF THE BOUNDARY LAYER QUALITY. HOWEVER...IT STILL APPEARS SUFFICIENT ENERGY AND INSTABILITY WILL BE PRESENT DURING THE HEAT OF THE DAY...WITH THE FLOW PATTERN CONCEPTUALLY MATCHING HISTORICALLY LARGE SEVERE WEATHER EPISODES. ALTHOUGH DEEP LAYER SHEAR PARAMETERS WILL BE MAXED OUT ON THE NOSE OF THE JET ROUNDING THE TROUGH BASE...LOW LEVEL WINDS MAY BE SOMEWHAT VEERED WITH LESSER SHEAR INTO THE CLOUD BASE. HOWEVER...THIS MAY JUST BE A LOW RESOLUTION MODEL ARTIFACT...AND WITH PRESSURE FALLS STILL REMAINING WEST OF THE CWA...BOUNDARY LAYER WINDS MAY REMAIN MORE BACKED THAN FORECAST. AS WITH SATURDAY...ALL MODES OF SEVERE WEATHER APPEAR POSSIBLE/PROBABLE SUNDAY...EXCEPT COVERAGE WOULD LIKELY BE FAR MORE EXPANSIVE...AND IMPACTING A DENSER POPULATION BASE. Link to comment Share on other sites More sharing options...
Indystorm Posted April 7, 2011 Share Posted April 7, 2011 Wow that briefing is about as strongly worded as they could possibly make it - strange for that far out. Hard to ramp down from that. Well, it is for emergency managers and not the general public. When I went to the advanced day long spotter training session I could sense that some of our IWX mets are itching for svr wx season to begin. Sounds like some of us. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 7, 2011 Share Posted April 7, 2011 First SPC MARS match for 500 mb heights for Sunday evening (00Z), just for fun. And here is the the reanalysis for that date/time in 1991. Not all that dissimilar to what the GFS shows attm. GFS is closing the upper low off south (in Kansas rather than Nebraska), but pretty close. Not saying it will happen, but interesting to compare. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 7, 2011 Share Posted April 7, 2011 GFS Cape & SRH 0-3km for Saturday Evening at 00z Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 7, 2011 Author Share Posted April 7, 2011 something that I like to look at...highest theta-e values we have seen all year at both 850mb and the sfc. Link to comment Share on other sites More sharing options...
OceanStWx Posted April 7, 2011 Share Posted April 7, 2011 Interesting seeing a number of the models hinting at this set up, a dry line/triple point mixing east along the IA/MO border. This example is the GFS, which doesn't have the trailing cold front overtaking the dry line until 06z Monday. Edit: Made those boundaries easier for folks to see. Link to comment Share on other sites More sharing options...
L.B. LaForce Posted April 7, 2011 Share Posted April 7, 2011 Kirksville part deux? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 7, 2011 Author Share Posted April 7, 2011 Interesting seeing a number of the models hinting at this set up, a dry line/triple point mixing east along the IA/MO border. This example is the GFS, which doesn't have the trailing cold front overtaking the dry line until 06z Sunday night. Edit: Made those boundaries easier for folks to see. Ya its really going to be interesting is to how the sfc low situation places out on sunday. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 7, 2011 Author Share Posted April 7, 2011 Kirksville part deux? And thats newer Thompson method which is usually a bit lower and smaller of an area. Kirksville without the rain wrapped part lol. Link to comment Share on other sites More sharing options...
TheWeatherPimp Posted April 7, 2011 Share Posted April 7, 2011 I'm liking Northeastern Missouri/Western Illinois right now (of course the radar hole of the Midwest). Link to comment Share on other sites More sharing options...
Kevin Askew Posted April 7, 2011 Share Posted April 7, 2011 I'm liking Northeastern Missouri/Western Illinois right now (of course the radar hole of the Midwest). Yeah yesterday picked Quincy IL For Sunday evening target for now. Still holding to that and your right the radar hole for sure.. Link to comment Share on other sites More sharing options...
wisconsinwx Posted April 7, 2011 Share Posted April 7, 2011 Do you guys think the Lower Lakes (Chicago/Milwaukee/Detroit and areas in between) will see tornadic storms Saturday or Sunday? Link to comment Share on other sites More sharing options...
Thundersnow12 Posted April 7, 2011 Author Share Posted April 7, 2011 Yeah yesterday picked Quincy IL For Sunday evening target for now. Still holding to that and your right the radar hole for sure.. What's the point of picking a target before the day 3 is even out? lol I don't get that. Things are most likely going change, and thats not including the mesoscale. Link to comment Share on other sites More sharing options...
csnavywx Posted April 7, 2011 Share Posted April 7, 2011 Kirksville part deux? Perhaps later in the night. The problem with setting up there for initiation is the fact that there's a well-agreed upon 500mb s/w ridge that helps keep things capped that far east (and slight height rises aloft). The better height falls are further west over far SW Iowa, NW Missouri and over into E NE/KS, and this would be the region to look for initiation, imo. Storms that get going farther west will have a great environment to move into later however, so some long-lived supercells seem probable. Edit: This is again, all based off current model consensus, which is still on the 3-day timeframe, and should be taken with a grain of salt. Link to comment Share on other sites More sharing options...
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