Powerball Posted May 31, 2011 Share Posted May 31, 2011 Central Lower Michigan could be looking at one heck of a damaging wind event latter today. Going to be very interesting watching this unfold. Yep, SW Michigan and Northern/Central Lower Michigan are looking real ominous today, especially with several hours of full sunshine and highs around 90*F ahead of it. Sunday and last Tuesday were impressive with only partial sunshine, so today could really be active. That outflow in Western Wisconsin/Illinois should be the focus for convective initiation. I would also keep an eye on the latest trends too. The recent model runs are veering the winds from a more favorable direction. That could lead to a enhanced tornado threat. Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 On the latest SPC update, a narrowing slight risk area has been extended SSW through St. Louis and a tiny narrow slither of the moderate risk area has been expanded into NW Indiana. The entire slight risk area has also been adjusted a hair to the SE. Except for an extension of the 45% area with the narrow moderate risk slither in NW Indiana and the 15% slight risk down to St. Louis, there were no significant changes. Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 31, 2011 Author Share Posted May 31, 2011 Don't get too jacked, timing is looking less than ideal for this side of the lake, visible shows clouds moving in pretty soon, so passage will be well before peak heating. http://www.ssec.wisc...wisgifloop.html Timing's rarely ideal around here anyway, so I'm used to it. It is unfortunate in that I work until 3:30 today, but it's better than storms moving through in the middle of the night. Link to comment Share on other sites More sharing options...
L.B. LaForce Posted May 31, 2011 Share Posted May 31, 2011 I'm not seeing the backed sfc winds. I'm seeing a whole crapton of unidirectional shear. Link to comment Share on other sites More sharing options...
hm8 Posted May 31, 2011 Share Posted May 31, 2011 MUCAPE already at 2000-3000 across MI Link to comment Share on other sites More sharing options...
kab2791 Posted May 31, 2011 Share Posted May 31, 2011 I guess mostly linear damaging wind threat is the way to go across the state with the low outside chance of a spin-up. I'm not seeing the backed sfc winds. I'm seeing a whole crapton of unidirectional shear. Link to comment Share on other sites More sharing options...
SEMIweather Posted May 31, 2011 Share Posted May 31, 2011 I guess mostly linear damaging wind threat is the way to go across the state with the low outside chance of a spin-up. I agree with this. Should be a fairly widespread threat. Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 31, 2011 Author Share Posted May 31, 2011 Looks like some storms starting to pop in Southcentral and Southwestern Wisconsin. A bit sooner than I'd like, but here in Milwaukee we will still probably have a couple more hours of daytime heating to work with. Link to comment Share on other sites More sharing options...
Stevo6899 Posted May 31, 2011 Share Posted May 31, 2011 Still confused with the coorelation with cape and the cap. The higher the cape the more likely the cap is able to be broken so storms can fire? Or can the cap be so strong sometimes that it doesn't matter what the cape is. Thanks for any input. Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 Still confused with the coorelation with cape and the cap. The higher the cape the more likely the cap is able to be broken so storms can fire? Or can the cap be so strong sometimes that it doesn't matter what the cape is. Thanks for any input. CAPE levels and cap strength have no correlation, except in extreme cases. You can have 7000 J/KG of CAPE but if the cap is too strong then you won't have any storms. It's all in the mid-level (700mb) temps. The warmer they are the stronger the cap is and the harder it'll be to break. When the mid-levels cool or the air below it is warm enough to break it (and as I said you would need extreme warming in this case to break it) is when storms can fire. A forcing machanism such as a cold front, warm front or outflow may also be enough to break it, as they can provide enough forcing of the airmass below the cap to eventually help it break through the cap. In this case we'll have to rely on mid-level cooling and the forcing from the cold front to help break the cap we have Link to comment Share on other sites More sharing options...
L.B. LaForce Posted May 31, 2011 Share Posted May 31, 2011 GRR was concerned with low level CAPE, but RUC says there is plenty Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 31, 2011 Author Share Posted May 31, 2011 Is that narrow line of showers/t'storms back by Madison the location of the cold front, or is the precip slightly ahead of the front? Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 I'm not seeing the backed sfc winds. I'm seeing a whole crapton of unidirectional shear. Some of the models were briefly showing the winds backing to the S/SSE later today. They've backed off again, but it could change. Link to comment Share on other sites More sharing options...
hm8 Posted May 31, 2011 Share Posted May 31, 2011 HRRR says bust for the mod zone but has a nice line in NW OH... Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 wisconsinwx, that's the left over crap from last night's storms. Cold front's just east of a Minneapolis-Des Moines line. Basically where the sharp cloud line is in the sattelite image. The outflow from last night's storms is already along a Grand Rapids-Gary line Link to comment Share on other sites More sharing options...
SEMIweather Posted May 31, 2011 Share Posted May 31, 2011 One of the few times we'll have this much surface heating in Lower MI. Link to comment Share on other sites More sharing options...
wisconsinwx Posted May 31, 2011 Author Share Posted May 31, 2011 wisconsinwx, that's the left over crap from last night's storms. Cold front's just east of a Minneapolis-Des Moines line. Basically where the sharp cloud line is in the sattelite image. The outflow from last night's storms is already along a Grand Rapids-Gary line I was just wondering. MKX's discussion said they expected the front to enter Wisconsin around 12z, so it made sense that it would be already by Madison at this point. Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 Moderate risk has been adjusted SE to include the areas that were formerly in the 30% wind area. Far NW Lower Michigan is out The western edge of the slight risk has been shaved a bit more, the narrow SW area around St. Louis is gone again and much of Ohio is now in the slight risk area. Link to comment Share on other sites More sharing options...
L.B. LaForce Posted May 31, 2011 Share Posted May 31, 2011 Moderate risk has been adjusted SE to include the areas that were formerly in the 30% wind area. Far NW Lower Michigan is out The western edge of the slight risk has been shaved a bit more, the narrow SW area around St. Louis is gone again and much of Ohio is now in the slight risk area. Oh wow, they updated early Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 Details: 30% hail area hasn't change in Michigan, but the portion in WI/IL is gone. 45% wind area has been removed from far NW lower Michigan and adjusted SE. The SW portion of the 5% tornado area has been shaved a bit 30% wind area now includes NW Ohio and I believe was also shaved some on the SW edge. Link to comment Share on other sites More sharing options...
hm8 Posted May 31, 2011 Share Posted May 31, 2011 Shweeet Kinda feel bad for the UP/ Upper LP of MI....went from Day 2 30% hatched just a regular 15%. Link to comment Share on other sites More sharing options...
kab2791 Posted May 31, 2011 Share Posted May 31, 2011 I'm liking the already steep mid-level lapse rapse rates, LIs around -6 to -7 and MLCAPES of 2000+. Link to comment Share on other sites More sharing options...
Hoosier Posted May 31, 2011 Share Posted May 31, 2011 Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 MUCAPE values are already 4000+ J/KG in much of Ohio up through Detroit. and LI's are -10 or better. It's rare we have that type of instability this way. DCAPE is 1500 J/KG. Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 FWIW, DTX posted a briefing for the severe weather, but it came out before the SPC update. Best time according to them is between 5 PM and 9 PM. Link to comment Share on other sites More sharing options...
kab2791 Posted May 31, 2011 Share Posted May 31, 2011 CU bubbling a bit along existing boundary over Western lower MI Link to comment Share on other sites More sharing options...
weathergy Posted May 31, 2011 Share Posted May 31, 2011 Could see much tree damage out of this, winds will be coming from a direction trees aren't used to. Link to comment Share on other sites More sharing options...
Stebo Posted May 31, 2011 Share Posted May 31, 2011 CU bubbling a bit along existing boundary over Western lower MI Yeah that CU line from Mount Pleasant down to Benton Harbor will probably be our big line. Link to comment Share on other sites More sharing options...
kab2791 Posted May 31, 2011 Share Posted May 31, 2011 GRR: .SHORT TERM...(100 PM EDT TUE MAY 31 2011)(THIS AFTERNOON THROUGH WEDNESDAY) THERE IS A SIGNIFICANT THREAT FOR SEVERE WEATHER THIS AFTERNOON AND EVENING OVER MUCH OF SOUTHWEST LOWER MICHIGAN. THE MAIN THREAT IS DAMAGING WINDS...HOWEVER TORNADOES ALSO WILL BE POSSIBLE. LATEST SPC OBJECTIVE ANALYSES INDICATE BUILDING INSTABILITY /MLCAPE ALREADY GREATER THAN 2500 J PER KG/ ACROSS MUCH OF LOWER MI. PER 12Z ILX RAOB AND RECENT AIRCRAFT SOUNDINGS...CAP ASSOCIATED WITH EML CONTINUES TO ERODE IN RESPONSE TO LARGE SCALE UPPER FORCING ASSOCIATED WITH INTENSE UPPER PV MAXIMUM MOVING NORTHEAST INTO MN. VWPS AT DVN BENEATH THE APPROACHING AREA OF SUBSIDENCE SEEN ON WV SATELLITE INDICATE STRONG UNIDIRECTIONAL SHEAR...PARTICULARLY BELOW 3 KM. THE NE DIRECTION OF THE SHEAR VECTOR CROSSING THE N-S FRONTAL BOUNDARY SEEN MOVING INTO WI SUGGESTS A MIXED MODE OF CONVECTION... WITH A TRANSITION FROM SUPERCELLS TO A QLCS OVER SRN LOWER MI THIS AFTERNOON. SIGNIFICANTLY...THE NEAR SURFACE FLOW DIRECTION PARALLELS A SUBSTANTIAL FETCH OF SE LAKE MICHIGAN. THIS OFTEN FAVORS INITIAL CONVECTIVE DEVELOPMENT ALONG A BAROCLINICALLY STRENGTHENED HORIZONTAL CONVECTIVE ROLL EXTENDING DOWNWIND /NORTHEAST/ FROM THE SOUTH HAVEN AREA. THIS COULD MARK THE WESTERN EDGE OF THE INITIAL SEVERE WEATHER THREAT THIS AFTERNOON. ANOTHER WAVE OF SEVERE CONVECTION WITH DAMAGING WINDS WILL BE POSSIBLE ACROSS THE ENTIRE CWFA EARLY THIS EVENING WITH THE APPROACH OF THE COLD FRONT AND ATTENDANT DEEP LAYER FORCING...SHEAR AND INSTABILITY. THE WIND DAMAGE THREAT REMAINS ELEVATED BY THE SIGNIFICANT DRY AIR PUNCH SEEN ON THE WV CHANNEL. Link to comment Share on other sites More sharing options...
Powerball Posted May 31, 2011 Share Posted May 31, 2011 MESOSCALE DISCUSSION 1039 NWS STORM PREDICTION CENTER NORMAN OK 1200 PM CDT TUE MAY 31 2011 AREAS AFFECTED...THE UPPER MS VLY AND UPR GRT LKS CONCERNING...SEVERE POTENTIAL...WATCH LIKELY VALID 311700Z - 311930Z LATEST SFC ANALYSIS SHOWS A COLD FRONT ARCING SOUTH AND SOUTHEAST ACROSS WRN ONT THROUGH WRN WI INTO ERN IA. THE FRONT IS MOVING ENE AT ABOUT 30 KT AND SHOULD EXTEND FROM WRN UPR MI THROUGH CNTRL WI INTO FAR ERN IA BY EARLY AFTN. AHEAD OF THE FRONT...RADAR AND VWP DATA SHOW A LOW LVL WIND SHIFT LINE LEFT OVER FROM LAST EVENINGS MCS IN THE DAKOTAS/NEB. THIS LINE IS JUST NOW CROSSING LK MI...AND SHOULD CONTINUE ENE AT ABOUT THE SAME SPEED AS THE COLD FRONT. FINALLY...IN THE INCREASINGLY WARM AND UNSTABLE AIR AHEAD OF THE WIND SHIFT LINE...TCU ARE GROWING OVER THE NRN HALF OF LWR MI. ATTM...WATER IMAGERY AND PROFILER/VWP DATA SHOW A STRONG N-S SHORTWAVE IMPULSE OVER CNTRL MN BEGINNING TO TAKE ON A NEGATIVE TILT. THIS IMPULSE...MARKED BY AN 80 KT 500 MB JET STREAK ...SHOULD ACCELERATE NEWD ACROSS CNTRL/NRN MI LATER TODAY WHILE THE PARENT UPR LOW EDGES MORE SLOWLY ENE FROM MB INTO ONT. COMBINATION OF CONTINUED SFC HEATING...LOW LVL MOISTURE INFLOW...AND LARGE SCALE ASCENT WITH UPR IMPULSE EXPECTED TO FOSTER RAPID TSTM DEVELOPMENT IN THE NEXT COUPLE OF HOURS ALONG THE COLD FRONT...THE WIND SHIFT LINE...AND WITHIN THE TCU FIELD. GIVEN STRENGTH OF DEEP...LARGELY UNIDIRECTIONAL SWLY FLOW AND FAVORABLE THERMODYNAMIC SETUP...POTENTIAL WILL EXIST FOR UPSCALE DEVELOPMENT OF THE STORMS INTO ONE OR MORE FORWARD-PROPAGATING SQLNS. EMBEDDED BOWING STRUCTURES AND SUPERCELLS IN THE SQLNS WILL HAVE THE POTENTIAL FOR VERY DMGG WIND...IN ADDITION TO LARGE HAIL AND POSSIBLY A COUPLE TORNADOES. ..CORFIDI.. 05/31/2011 ATTN...WFO...DTX...APX...GRR...MQT...GRB...MKX...DLH...ARX... LAT...LON 44059036 45549029 46669035 47258982 47408713 46388392 45278304 44158353 43458536 43658933 44059036 Link to comment Share on other sites More sharing options...
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