SolidIcewx Posted July 28, 2021 Share Posted July 28, 2021 With a shift more to the northeast I wonder if it makes the Detroit Metro area more in play instead of sinking to the southwest Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 28, 2021 Share Posted July 28, 2021 If the CAM solutions are right, Madison doesn't need to be in the Enhanced risk. HRRR and 3K NAM still largely agree on a whiff northeast. Now that I check the WRFs, they give us some storms but not nearly as potent as points north/east.They’ll be too far northeast.The biggest question is how quickly the threat fades with southeastward extent. The moderate risk to MKE seems be wishful thinking.. Link to comment Share on other sites More sharing options...
Indystorm Posted July 28, 2021 Share Posted July 28, 2021 I'm tending to agree with Purduewx here and thinking the CAMS might be off a bit and too far ne. As I look at current satellite, radar, and SPC meso values I'm leaning to a more north south orientation as well a bit farther west. The instability gradient will be all important in its location for what transpires this evening and tonight in the affected areas. 1 Link to comment Share on other sites More sharing options...
RyanDe680 Posted July 28, 2021 Share Posted July 28, 2021 Got that meh feeling Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 28, 2021 Share Posted July 28, 2021 Interesting curl shape/possible broad cyclonic rotation to the southwest edge of the anvil debris/cirrus clouds currently drifting southeast through central Iowa. Not sure if that has any implications on the scenario for later. The cloud deck in general appears to finally be shrinking/dissipating with heating building back in over MN/IA. Edit: No change to the southwestern edge of the risk areas at 1630Z, slight/marginal expanded to the northeast. Link to comment Share on other sites More sharing options...
purduewx80 Posted July 28, 2021 Share Posted July 28, 2021 1 minute ago, CheeselandSkies said: Interesting curl shape/possible broad cyclonic rotation to the southwest edge of the anvil debris/cirrus clouds currently drifting southeast through central Iowa. Not sure if that has any implications on the scenario for later. The overnight MCV is being sheared apart due to the strong winds aloft - def can see those remnants aloft w/ the feature over IA. The only implication I can see related to that is the min in instability caused by the warm front being driven S/W by an outflow boundary. Recovery can happen quickly in this setup during the late PM hours, but it's not totally clear where the instability gradient will be as TS ride the ridge SE and then S tonight. The latest HRRR does capture current instability fields relatively well. Hate to say this, but the 12Z GFS actually looks more reasonable than a lot of the CAMs from what I'm seeing so far. First warning up by Lake of the Woods now. Will be very interesting to see if that's the start of the main show (probably so). Link to comment Share on other sites More sharing options...
Avon Posted July 28, 2021 Share Posted July 28, 2021 Update from Grand Rapids..... Area Forecast Discussion National Weather Service Grand Rapids MI UPDATE... Issued at 1225 PM EDT Wed Jul 28 2021 Latest 12Z guidance is continuing the farther north trend of the most severe convection later tonight, even hinting at the possibility of a derecho impacting much or parts of wrn Lwr MI. Since this is a potentially high impact severe weather event while many folks will be sleeping, communication/messaging the possibility of high/destructive winds this afternoon/evening will be critical. Timing looks to be similar, with potential for a large bow echo sweeping across Lk MI toward or after midnight. Also some potential for the warm advection wing ahead of the main line becoming active a couple hours beforehand. If that does occur, we could have some tornado potential with discrete cells since the warm front will be draped over the area. HRRR has 0-1km SRH of 150-200 m2/s2 with LCLs below 1km. A QLCS-type tornado threat may also develop/exist within the main line. Also of note, in terms of the straight line wind potential, HRRR shows 70 kts at 3 km, of potential descending rear inflow into the back of that line. So some isolated pockets of destructive 80+ mph winds seem plausible later tonight. As far as heavy rainfall/flooding concerns, some intense rainfall rates are likely as the strong/svr convection is coming through tonight, although the progressive nature of the MCS may limit the overall flooding risk. That said, some urban flooding - possibly worthy of areal flood advisories/warnings - may also be needed. Link to comment Share on other sites More sharing options...
A-L-E-K Posted July 28, 2021 Share Posted July 28, 2021 gonna ride instability gradient down I90 into ne il 1 3 1 Link to comment Share on other sites More sharing options...
Tezeta Posted July 28, 2021 Share Posted July 28, 2021 What even constitutes a good derecho these days for you guys? After Iowa I think it would be hard to get off on more run of the mill events. At least that’s been my experience with tropical stuff. What sort of wind gusts will you need to see to not say meh? 1 Link to comment Share on other sites More sharing options...
yoda Posted July 28, 2021 Share Posted July 28, 2021 Day 1 Convective Outlook NWS Storm Prediction Center Norman OK 0300 PM CDT Wed Jul 28 2021 Valid 282000Z - 291200Z ...THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS WISCONSIN...SOUTHERN HALF OF LAKE MICHIGAN...SOUTHWEST LOWER MICHIGAN... ...THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS SOUTHEAST VIRGINIA...EASTERN NORTH CAROLINA... ...SUMMARY... Potentially widespread severe thunderstorms are expected late this afternoon through tonight along a corridor from northeastern Minnesota across Wisconsin into southwest Lower Michigan. A few severe storms are also expected this afternoon over parts of Virginia and North Carolina. ...Discussion... The only change this outlook update is to upgrade severe-wind probabilities from the southern half of Lake Michigan southeastward into northwest OH. Recent runs of the HRRR indicate an intense rear inflow jet late tonight as a bow moves southeastward across Lake Michigan into the Michiana vicinity. Confidence in a widespread severe-gust threat has increased and is depicted in the minor nudges upwards in probabilities. ..Smith.. 07/28/2021 Link to comment Share on other sites More sharing options...
sbnwx85 Posted July 28, 2021 Author Share Posted July 28, 2021 SPC pushes moderate risk into Western Michigan/extreme N. Indiana. Zoomed in view. 2 Link to comment Share on other sites More sharing options...
Jim Martin Posted July 28, 2021 Share Posted July 28, 2021 Link to comment Share on other sites More sharing options...
Chicago Storm Posted July 28, 2021 Share Posted July 28, 2021 5 hours ago, Chicago Storm said: They’ll be too far northeast. The biggest question is how quickly the threat fades with southeastward extent. The moderate risk to MKE seems be wishful thinking. . And then they double down, and bring the mod risk to the IL/WI border and into NW MI/N IN. Likely overdone. 2 Link to comment Share on other sites More sharing options...
nwohweather Posted July 28, 2021 Share Posted July 28, 2021 Atmosphere just looks so ripe, even into the overnight hours. So much moisture and shear available for the expected bow echo that it should be able to absolutely roar tonight. Wouldn't be shocked to see even a strong tornadic spin up as well in that line. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 28, 2021 Share Posted July 28, 2021 First MD out just for 40% probability of a watch over north-central MN (slight risk area). Still in watchful waiting mode. Link to comment Share on other sites More sharing options...
yoda Posted July 28, 2021 Share Posted July 28, 2021 Mesoscale Discussion 1378 NWS Storm Prediction Center Norman OK 0509 PM CDT Wed Jul 28 2021 Areas affected...portions of east-central and northeast MN...northern WI Concerning...Severe potential...Tornado Watch likely Valid 282209Z - 290015Z Probability of Watch Issuance...95 percent SUMMARY...Rapid development of supercell thunderstorms is anticipated in the next few hours, with a risk for very large hail, damaging winds, and potentially a few tornadoes. A Tornado Watch will likely be issued prior to 00z. DISCUSSION...A warm front extended south/southeast across central/southern MN at 22z, and this front will continue to move east through this evening as a weak surface low moves east across central MN. Latest visible imagery reveals moderate/towering cumulus over central MN north of the Twin Cities area, embedded within a larger area of clouds over central/northern MN and northern WI. Current expectations are for thunderstorms to develop in the next few hours near the warm front and move southeast during the evening. Northwesterly deep-layer shear of 45-55 kts in the vicinity of the front will support intense supercells initially, and locally-enhanced 0-3 km SRH will be favorable for low-level rotation and potential for tornado development. Steep mid-level lapse rates will also support a risk for very large hail, and damaging winds are also expected. Current thinking is that the tornado threat will warrant a Tornado Watch for the first few hours after initiation given the near-storm environment, with eventual transition into a fast-moving MCS with widespread damaging wind potential later this evening/overnight. A Tornado Watch will likely be coordinated with affected NWS Weather Forecast Offices prior to 00z. ..Bunting/Goss.. 07/28/2021 ...Please see www.spc.noaa.gov for graphic product... ATTN...WFO...DLH...ARX...MPX... Link to comment Share on other sites More sharing options...
yoda Posted July 28, 2021 Share Posted July 28, 2021 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 28, 2021 Share Posted July 28, 2021 Now we're talking. Sun's back out here, after we were overcast for a time this afternoon. Link to comment Share on other sites More sharing options...
StormfanaticInd Posted July 28, 2021 Share Posted July 28, 2021 If a tornado forms in this environment watch out. Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 28, 2021 Share Posted July 28, 2021 HRRR gradually trending toward bringing the western end of the MCS over the Madison area, although weakened from earlier, but of course it wants to bring the storms through right when I'll be commuting to work. Link to comment Share on other sites More sharing options...
Jim Marusak Posted July 28, 2021 Share Posted July 28, 2021 so, your thoughts... are we waiting on the 00Z RAOBS for the watch issuance, or for more TCU's to go up quickly? Link to comment Share on other sites More sharing options...
Sydney Claridge Posted July 28, 2021 Share Posted July 28, 2021 1 hour ago, StormfanaticInd said: If a tornado forms in this environment watch out. The parameters for significant tornadoes and the Violent Tornado Parameter are both very high over the Twin Cities metro area. These parameters are not everything by themselves, but still, it is not an environment you would want a supercell to form and then go on to produce a significant tornado, especially over a highly populated metropolitan area like MSP. 1 Link to comment Share on other sites More sharing options...
Tezeta Posted July 28, 2021 Share Posted July 28, 2021 Is this gonna bust? 1 Link to comment Share on other sites More sharing options...
CheeselandSkies Posted July 29, 2021 Share Posted July 29, 2021 MD expires in 12 minutes and no watch yet... Link to comment Share on other sites More sharing options...
Tezeta Posted July 29, 2021 Share Posted July 29, 2021 1 minute ago, CheeselandSkies said: MD expires in 12 minutes and no watch yet... That’s what has me scared. I live on the west coast and figured by the time I got home from work I’d have something to track. Link to comment Share on other sites More sharing options...
Indystorm Posted July 29, 2021 Share Posted July 29, 2021 700mb temps still 10-12 in the affected area where we anticipate a watch. Cap? Link to comment Share on other sites More sharing options...
Jim Marusak Posted July 29, 2021 Share Posted July 29, 2021 Just now, Indystorm said: 700mb temps still 10-12 in the affected area where we anticipate a watch. Cap? off the MPX RAOB, or INL? Link to comment Share on other sites More sharing options...
Indystorm Posted July 29, 2021 Share Posted July 29, 2021 SPC meso page for what it is worth Link to comment Share on other sites More sharing options...
Jim Marusak Posted July 29, 2021 Share Posted July 29, 2021 ok. just was wondering. because those RAOBS might be what is the final piece they're looking at (as well as the storms up in NW Itasca County). Link to comment Share on other sites More sharing options...
HillsdaleMIWeather Posted July 29, 2021 Share Posted July 29, 2021 Severe Thunderstorm Watch issued Link to comment Share on other sites More sharing options...
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