daddylonglegs Posted May 2, 2012 Share Posted May 2, 2012 La Crosse doesn't seem hyped on anything in my backyard: FOR THE AFTERNOON...CONVECTION NEAR THE OUTFLOW SHOULD CONTINUE TO DIMINISH AS THE CAPPING MOVES NORTHEAST...AND THE OVERALL LOW LEVEL JET DIMINISHES WITH THE TYPICAL DIURNAL WEAKENING. WAS INITIALLY CONCERNED THAT SURFACE BASED CONVECTION WOULD FIRE ON THE OUTFLOW BOUNDARY IN NORTHERN MISSOURI. IF THIS OCCURRED...WE COULD GET COMPLETELY SHUT OUT OF ANY CONVECTION IN THE FORECAST AREA FOR THE AFTERNOON AND EVENING. HOWEVER...THERE APPEARS TO BE WAY TOO MUCH CAPPING OVER NORTHERN MISSOURI. CURRENTLY MLCIN VALUES ARE AROUND 100 J/KG. NOW THE WESTERN EDGE OF THE OUTFLOW IN FAR EASTERN NEBRASKA LOOKS MORE REASONABLE TO CONVECT...ESPECIALLY NORTH OF OMAHA WHERE CAPPING IS LESS SUBSTANTIAL. ANTICIPATING CONVECTION TO DEVELOP THERE TOWARDS 21Z...WITH CORFIDI VECTORS SUGGESTING A MOVEMENT EASTWARD THEN SOUTHEASTWARD THROUGH IOWA TONIGHT. THE 02.00Z HIRES ARW MODEL RUN AT NCEP SEEMS TO HANDLE THIS WELL... AND ALSO MIMICS WHERE SPC DAY 1 MODERATE RISK AREA EXISTS. PERHAPS A PORTION OF THIS MCS CLUSTER MAY CLIP OUR NORTHEAST IOWA COUNTIES TONIGHT...LIKELY AFTER 01Z OR SO. NOW AS FAR AS POSSIBLE DEVELOPMENT OVER THE FORECAST AREA. AM NOT SURE HOW FAR NORTH THE OUTFLOW BOUNDARY CAN MAKE IT UNDER THE CAP THIS AFTERNOON. HOWEVER...IT DOES APPEAR THIS EVENING THERE WILL BE AN INCREASE IN 850MB MOISTURE TRANSPORT WITH THE NOSE POINTING INTO LOCATIONS SOUTH OF I-90. 02.00Z ECMWF...WHICH IS HANDLING THE CURRENT CONVECTION FAIRLY WELL...SHOWS THIS MOISTURE TRANSPORT SURGE THE BEST. SO WOULD ENVISION MAYBE AFTER 22/23Z CONVECTION FIRING ACROSS NORTHERN IOWA...THEN SPREADING EAST ALONG THE GRADIENT OF MOISTURE TRANSPORT. REGARDING OTHER MODEL DATA...PROBLEMS WITH A LOT OF IT IS EITHER THEY ARE NOT MIMICKING THE OUTFLOW BOUNDARY WELL IN THE WIND FIELDS...AND/OR THE DEWPOINTS ARE WAY TOO HIGH ACROSS IOWA. THEREFORE...THIS FORECAST LEANS TOWARDS THE 22.00Z HIRES ARW/ECMWF MODELS. SEVERE WEATHER RISKS STILL APPEAR TO BE LARGE HAIL...DAMAGING WINDS AND HEAVY RAIN. CANNOT RULE OUT COMPLETELY A TORNADO OCCURING...BUT WE REALLY NEED TO HAVE THAT OUTFLOW BOUNDARY LIFT NORTH INTO THE AREA. IF ANY SPOT HAS A CHANCE TO SEE A TORNADO IT WOULD BE IN NORTHEAST IOWA...CLOSEST TO THE OUTFLOW LIFTING NORTH. Link to comment Share on other sites More sharing options...
cyclone77 Posted May 2, 2012 Share Posted May 2, 2012 LOL @ RAP bumping cape up to 4000j/kg from nearly 0j/kg in 6hrs over western IL. This model may be even more aggressive than the RUC was. Link to comment Share on other sites More sharing options...
Geos Posted May 2, 2012 Share Posted May 2, 2012 MKX's thoughts on today and tonight: DEEPER MIXING IS TAKING PLACE IN SOUTHEAST WI NEAR THE LAKE AND SHOULD CONTINUE THROUGH AT LEAST EARLY AFTERNOON. DRY WEATHER EXPECTED ACROSS WHOLE FORECAST AREA UNTIL AFTER 00Z. THERE IS A POSSIBILITY THAT A FIRST ROUND OF CONVECTION COULD FIRE UP IN NORTHEAST IOWA AND TRACK EAST ACROSS SOUTHERN WI AS THE 850MB LOW LEVEL JET NOSES INTO THE AREA. HOWEVER...RESIDUAL CLOUDS AND STABLE ATMOSPHERE DUE TO LAST NIGHT/S CONVECTION MAY HINDER THAT DEVELOPMENT. CONVECTION IS NEARLY IMMINENT IN EASTERN NEBRASKA LATE THIS AFTERNOON AND A CLUSTER OF THUNDERSTORMS WILL TRACK EAST OVERNIGHT. THEY MAY TRACK JUST SOUTH OF THE WI BORDER OR MAY GO RIGHT ACROSS SOUTHERN WISCONSIN. EXPECTING A LULL BEHIND THAT ROUND OF CONVECTION THROUGH LATE MORNING. THEN ALL BETS ARE OFF AS TO WHEN AND WHERE THE NEXT ROUND OF CONVECTION WILL FIRE SINCE THAT WILL DEPEND ON TONIGHT/S CONVECTION. Link to comment Share on other sites More sharing options...
Gilbertfly Posted May 2, 2012 Share Posted May 2, 2012 Filtered sun...DP has subsided a tad....looks like a little bit trying to get brewing in W IL . . . nothin' to write home about ATM... gusty westerlies have also finally subsided....near calm ATM Link to comment Share on other sites More sharing options...
hm8 Posted May 2, 2012 Share Posted May 2, 2012 DTX Aviation update isn't awesome sounding... AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 150 PM EDT WED MAY 2 2012 .AVIATION... //DISCUSSION... A WARM FRONT WILL ADVANCE ACROSS SOUTHEAST MICHIGAN THROUGH THE LATTER HALF OF THE DAY. WHILE THIS WILL PROVIDE AN INCREASINGLY MOIST AND UNSTABLE ENVIRONMENT THROUGH EARLY EVENING...CONFIDENCE IN POTENTIAL THUNDERSTORM DEVELOPMENT/COVERAGE ALONG THIS BOUNDARY REMAINS QUITE LOW. THE WINDOW FOR THUNDERSTORMS APPEARS SMALL /20-23Z/...AND GIVEN THE UNCERTAINTY WILL HOLD OFF ON DEFINING ANY SPECIFIC TSRA MENTION WITH THIS TAF PACKAGE. A WELL MIXED SOUTH-SOUTHWEST WIND EMERGING WITHIN THE FRONTAL PASSAGE WILL BRING SOME GUSTS TO 20 KNOTS PRIOR TO 00Z. Link to comment Share on other sites More sharing options...
aurora Posted May 2, 2012 Share Posted May 2, 2012 Appears we may be getting close to initiation in the Thumb. Link to comment Share on other sites More sharing options...
Thundersnow12 Posted May 2, 2012 Share Posted May 2, 2012 12z NMM with a few complexes tomorrow night. Link to comment Share on other sites More sharing options...
hm8 Posted May 2, 2012 Share Posted May 2, 2012 MESOSCALE DISCUSSION 0660 NWS STORM PREDICTION CENTER NORMAN OK 0157 PM CDT WED MAY 02 2012 AREAS AFFECTED...LOWER MI CONCERNING...SEVERE POTENTIAL...WATCH POSSIBLE VALID 021857Z - 022030Z PROBABILITY OF WATCH ISSUANCE...40 PERCENT SUMMARY...POTENTIAL EXISTS FOR AN INCREASING SEVERE TSTM THREAT THIS AFTERNOON ACROSS EAST/SOUTHEAST PORTIONS OF LOWER MI...WHICH COULD INCLUDE A RISK FOR A TORNADO ASIDE FROM SEVERE HAIL/WIND. DISCUSSION...IT APPEARS THAT THE REGION IS BEING INFLUENCED BY THE SOUTHERN/TRAILING PORTION OF A NORTHEAST-MOVING SHORTWAVE TROUGH OVER THE UPPER GREAT LAKES REGION INTO ONTARIO THIS AFTERNOON. A RECENT INCREASE/DEEPENING OF THE CU FIELD HAS BEEN NOTED IN EAST-CENTRAL LOWER MI PER VISIBLE SATELLITE IMAGERY...AND THIS ROUGHLY COINCIDES WITH A CORRIDOR OF MAXIMIZED CONVERGENCE NEAR A WEAK FRONTAL WAVE/WARM FRONT. THERMODYNAMIC MODIFICATIONS TO THE 12Z OBSERVED SOUNDING FROM DETROIT...ALONG WITH SHORT-TERM RAP GUIDANCE/SPC OBJECTIVE ANALYSIS...SUGGEST THAT CINH IS NOW NEGLIGIBLE WITH A CORRIDOR OF MODERATE INSTABILITY EXTENDING NORTHEASTWARD INTO SOUTHEAST/EAST-CENTRAL LOWER MI. AMID RELATIVELY STRONG DEEP LAYER SOUTHWESTERLY FLOW...ORGANIZED/SUSTAINED STORM MODES INCLUDING SOME SUPERCELLS WOULD BE POSSIBLE SHOULD DEEP CONVECTIVE INITIATION OCCUR...WITH A TORNADO AND HAIL/WIND RISK CONDITIONALLY POSSIBLE. HOWEVER...UNCERTAINTY CURRENTLY EXISTS REGARDING THE LIKELIHOOD/EXTENT OF SAID SEVERE THREAT...ESPECIALLY GIVEN THAT MID-LEVEL WAVE WILL BE MOVING AWAY FROM THE REGION AND MASS CONVERGENCE/DEEP LAYER SHEAR SHOULD SLOWLY ABATE WITH TIME. SHORT-TERM TRENDS ARE BEING CLOSELY MONITORED FOR A POSSIBLE WATCH. ..GUYER/CARBIN.. 05/02/2012 Link to comment Share on other sites More sharing options...
hm8 Posted May 2, 2012 Share Posted May 2, 2012 DTX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DETROIT/PONTIAC MI 357 PM EDT WED MAY 2 2012 SHORT TERM THROUGH TONIGHT A RATHER CHALLENING AND ILL-DEFINED FORECAST /MAINLY IN TERMS OF THUNDER POTENTIAL/ BOTH IN THE IMMEDIATE NEAR TERM AND AGAIN LATE TONIGHT. AT THE SURFACE...LATEST ANALYSIS WRAPS A WARM FRONT FROM THE DETROIT CORRIDOR NORTHWEST ALONG I-75 AND THEN WEST THE LAKE MI SHORELINE SOUTH OF LUDINGTON. A GOOD PUSH OF WARM/MOIST AIR ADVECTION ALONG THE BACKEDGE OF THIS FRONTAL ZONE...AIDED BY DEEP MIXING...EFFECTIVELY DRIVING TEMPERATURES WELL INTO THE 70S TO AROUND 80F SOUTH. WHILE STRONGER LOW LEVEL DESTABILIZATION WILL REMAIN DEFINED TO OUR SOUTH/WEST...RECENT SPC MESOANALYSIS SUGGESTS A WINDOW FOR 0-1 KM MLCAPE TO ACHIEVE 1000-1500 J/KG ALONG AND SOUTH OF I-96 PRIOR TO SUNSET. DESPITE THE GROWING LOW LEVEL INSTABILITY AND PRESENCE OF A WARM FRONT...THE OVERALL SETUP STILL LACKS A MORE DEFINED FORCING MECHANISM TO ANCHOR CONVECTION AND CARRIES SOME CONCERNS AT THE MID LEVELS. WEAK LOW TO MID LEVEL CONVERGENCE AXIS CURRENTLY MARCHING EAST ACROSS SOUTHEAST MICHIGAN PROMOTING LITTLE MORE THAN SOME LOWER BASED CU DEVELOPMENT AT PRESS TIME. PLAUSIBLE SCENARIO REMAINS OVER THE NEXT 2-3 HOURS FOR SOME CONBINATION OF THIS BOUNDARY AND THE WARM FRONT TO FOCUS SCATTERED CONVECTION ACROSS THE SOUTH/EAST. NOTING THE RAPID CLEARING WORKING ACROSS WEST-CENTRAL LOWER MI...THERE DOES APPEAR TO BE A HIGHER DEGREE OF SUBSIDENCE WORKING IN BEHIND THIS FEATURE...SO THE WINDOW FOR DEVELOPMENT LOOKS SMALL /THROUGH 22Z/. IN ADDITION...MID LEVEL LAPSE RATES REMAIN MODEST. THIS CONDITIONAL CONVECTIVE THREAT WILL CARRY A RISK OF SEVERE WEATHER GIVEN A BACKGROUND WESTERLY WIND FIELD CONTAINING 25-30 KNOTS OF DEEP LAYER SHEAR. SUBSIDENCE WILL RAPIDLY MITIGATE THIS CONVECTIVE OPPORTUNITY HEADING INTO THE EVENING AND OVERNIGHT PERIOD. ATTENTION WILL REFOCUS TO THE WEST AS ADDITIONAL NOCTURNAL DEVELOPMENT LIKELY ORGANIZES INTO ONE MORE MCS ACROSS THE MIDWEST. POTENTIAL WILL EXIST FOR SOME REMNANT OF THIS ACTIVITY TO SPILL EAST/NORTHEAST AND BE AT THE DOORSTEP AS THE LOW LEVEL JET FORCING VEERS TOWARD DAYBREAK. A MILD NIGHT AHEAD...WITH LOWS IN THE UPPER 50S/LOWER 60S. Link to comment Share on other sites More sharing options...
SpartyOn Posted May 2, 2012 Share Posted May 2, 2012 Feels like good old fashion spring instability out there. Link to comment Share on other sites More sharing options...
hm8 Posted May 2, 2012 Share Posted May 2, 2012 There are some pretty looking parameters in SEMI right now (cape 2000-3000, supercell composite of 12, STP of 2, EHI of 6, etc)... problem is these will be on the decline and initiation, if it happens at all, won't be for another couple hours. Link to comment Share on other sites More sharing options...
aurora Posted May 2, 2012 Share Posted May 2, 2012 There are some pretty looking parameters in SEMI right now (cape 2000-3000, supercell composite of 12, STP of 2, EHI of 6, etc)... problem is these will be on the decline and initiation, if it happens at all, won't be for another couple hours. With each passing minute, today is looking more and more like a cap bust. Or, more accurately (since there is essentially no CIN according to mesoanalysis), there's just not enough of a trigger. Oh well, what can you do. The good news is, there's more chances tomorrow and Friday. Link to comment Share on other sites More sharing options...
Stebo Posted May 2, 2012 Author Share Posted May 2, 2012 Lack of forcing plus weak wind shear = no storms today for SEMI. Our hope is that stuff moves in tonight for some action. If not might have to wait until tomorrow. Link to comment Share on other sites More sharing options...
afterimage Posted May 2, 2012 Share Posted May 2, 2012 Interesting the little "jog" adjustment on the slight area, for the rest of today/tonight....has encompassed more of northern half IN Link to comment Share on other sites More sharing options...
afterimage Posted May 2, 2012 Share Posted May 2, 2012 I am kinda slow, and I now noticed this...shoulda posted it above.... http://www.spc.noaa.gov/products/md/md0662.html Link to comment Share on other sites More sharing options...
weathergy Posted May 2, 2012 Share Posted May 2, 2012 If we could get a lake breeze here in SEMI, it could initiate things, but the shortwave is really moving through just about closing the window. Link to comment Share on other sites More sharing options...
SpartyOn Posted May 2, 2012 Share Posted May 2, 2012 I'm sure we have all seen much better parameters but these are solid for MI. Whatever does go up it will explode fast and furious. Link to comment Share on other sites More sharing options...
Stebo Posted May 2, 2012 Author Share Posted May 2, 2012 Cells popping in Canada, looks like we have to wait for tonight around here. West of here Chicago and IL should get rocking late this evening though. Link to comment Share on other sites More sharing options...
weathergy Posted May 2, 2012 Share Posted May 2, 2012 Cells popping in Canada, looks like we have to wait for tonight around here. West of here Chicago and IL should get rocking late this evening though. Things might pop in Wanye county, and Monroe just as the convergence zone exits the state. Link to comment Share on other sites More sharing options...
turtlehurricane Posted May 2, 2012 Share Posted May 2, 2012 Convective plumes are becoming more vigorous along the boundary in Nebraska. Won't be long now until the cap blows with temps in the low 80s out there. Link to comment Share on other sites More sharing options...
turtlehurricane Posted May 3, 2012 Share Posted May 3, 2012 Cells beginning to take shape in eastern IA, heading northeast towards Wisconsin. Lots of hail reports with the intense line of cells south of Minneapolis, those are just beginning to enter northern WI. Link to comment Share on other sites More sharing options...
daddylonglegs Posted May 3, 2012 Share Posted May 3, 2012 Of course everything good is firing just to my north... Link to comment Share on other sites More sharing options...
cyclone77 Posted May 3, 2012 Share Posted May 3, 2012 Big changes to new SPC outlook. Eastern Iowa points east dropped from the slight risk. Link to comment Share on other sites More sharing options...
hawkeye_wx Posted May 3, 2012 Share Posted May 3, 2012 Quad Cities nws now also beginning to talk down tonight's action. Sheesh. For days tonight was expected to be a big night. Link to comment Share on other sites More sharing options...
Geos Posted May 3, 2012 Share Posted May 3, 2012 Link to comment Share on other sites More sharing options...
cyclone77 Posted May 3, 2012 Share Posted May 3, 2012 Quad Cities nws now also beginning to talk down tonight's action. Sheesh. For days tonight was expected to be a big night. All the cloud debris/leftover festering convection tomorrow morning will probably have an impact on tomorrow night's action too. Wouldn't be surprised to see the 30% probs dropped on the new day1. Already took away the hatched. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 3, 2012 Share Posted May 3, 2012 lack of a focused trigger really hasn't helped get over the somewhat marginal instability. Link to comment Share on other sites More sharing options...
IWXwx Posted May 3, 2012 Share Posted May 3, 2012 Talking about the possible reduction in on-site surveys, it sounds like this is one of them. Central Indiana - At least one tornado has been confirmed as part of the severe weather that produced flooding rains, hail to golf ball size and areas of wind damage Tuesday afternoon and evening. The tornado touched down southeast of Crawfordsville near New Ross along County Road 500S between CR625E and CR700E. From eyewitness Skywarn storm spotters' reports, pictures and videos of the tornado and damage, and from Indianapolis TV stations' damage pictures, the tornado is being rated preliminarily as an EF1 with winds estimated between 100 mph and 110 mph. The tornado began at approximately 736 pm, was on the ground for about a half mile, and lifted around 737 pm. The damage rating was based on a destroyed barn, and damaged nearby homes, trees and power poles. Other reports of brief tornadoes near Yeddo south of Veedersburg, near Cory southeast of Terre Haute, and near Columbus are still being investigated by county emergency management. As new details become available, they will be updated in this news story. Just getting caught up. I think they are making a big mistake in not sending NWS teams out to do damage surveys. There is a whole list of objections, not the least being a compromise of scientific study. I think that there is a thread on here somewhere discussing this, so I won't belabor the point. Link to comment Share on other sites More sharing options...
frostfern Posted May 3, 2012 Share Posted May 3, 2012 There is some development now just W of the Quad Cities. Also an E-W oriented boundary pushing north across southern WI looks to be the northern edge of the nocturnal LLJ in progress. Looks like stuff may fire north of that line first, then the squall line pushes east across all of southern WI and northern IL if it consolidates. Probably not going to reach Lake Michigan until around midnight though, unless more cells can develop ahead. Link to comment Share on other sites More sharing options...
A-L-E-K Posted May 3, 2012 Share Posted May 3, 2012 There is some development now just W of the Quad Cities. Also an E-W oriented boundary pushing north across southern WI looks to be the northern edge of the nocturnal LLJ in progress. Looks like stuff may fire north of that line first, then the squall line pushes east across all of southern WI and northern IL if it consolidates. Probably not going to reach Lake Michigan until around midnight though, unless more cells can develop ahead. midnight?!?...not even close Link to comment Share on other sites More sharing options...
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