Week of 7/26

[MWmetalhead]

My forecasted high temps for Detroit and for Grand Rapids:
7/26: (skipping since it's already 2:30 in the afternoon)
7/27: 86, 84
7/28: 83, 83
7/29: 83, 85
7/30: 85, 87
7/31: 85, 85
8/1: 82, 82
8/2: 83, 84

GFS model run from 8AM this morning; first number is projected 5PM temp for Detroit and second number is projected 5PM temp for Grand Rapids:

7/26: 83, 89 (Detroit is probably about right; Grand Rapids is likely a couple degrees too high)
7/27: 90, 90 (103 for Minneapolis and 112 for Omaha!)
7/28: 84, 87 (scorching heat wave for the deep south, the plains, and the rockies)
7/29: 80, 87 (Detroit temp is likely too low)
7/30: 84, 88
7/31: 87, 80
8/1: 84, 83
8/2: 80, 81

Euro-AIFS (Artificial Intelligence Forecasting System) model run from 8AM this morning; first number is projected 2PM temp for Detroit and second number is projected 2PM temp for Grand Rapids (I was unable to obtain 5PM data from this source):

7/26: 81, 85 (not bad; DTW is 83 and GRR is 84 as of 2PM)
7/27: 81, 79 (I think these readings are likely too low)
7/28: 80, 81
7/29: 79, 82
7/30: 82, 84
7/31: 84, 84
8/1: 78, 78
8/2: 81, 83

The heat dome's severity, geographic breadth, and longevity per the Euro is not nearly as prolific as what the GFS is suggesting. I think the GFS is out of control with its forecast.

I'll create a separate post for Monday's severe weather threat shortly.

[MWmetalhead]

Severe weather threat discussion for Monday:

-Storm relative helicity (0 to 3 km above ground level): GFS values peak at about 200 m2/s2 late Monday afternoon and early Monday evening. HRRR shows high values along the immediate MI/IN border into the northern half of Indiana midday & early afternoon Monday, with those high values being pushed quickly southward by mid afternoon.

-Bulk shear (0 to 6 km): Peak values around 50 knots into early evening Monday per the GFS. HRRR shows similar.

-Surface-based lift index: GFS shows healthy values of -6 to even -8 across much of lower Michigan from midday to early evening; The high values then shift south into Indiana and eastern Illinois by late evening. The HRRR shows flimsier values of - 3 or -4 throughout the period across lower Michigan, with much better lift centered over Illinois.

-Mixed-layer CAPE: HRRR keeps best instability over Illinois and southern Wisconsin, with Michigan values near or below 1000 j/kg throughout Monday and Monday night. My source does not show this value when using the GFS model.

-Surface-based CAPE: HRRR solution is very similar to mixed-layer CAPE solution. For the GFS, midday shows values above 2000 j/kg briefly sneaking into south central Michigan, with values above 2500 j/kg briefly sneaking into far SW lower Michigan in the late evening before quickly departing.

-Supercell composite: GFS shows northern IL and NW Indiana has having the best supercell environment. Far SW lower MI could get in on the action Monday evening, though. HRRR keeps all or nearly all of the nasty stuff across IL and western IN.

Conclusion:
- I'd say the severe weather probability for upper Michigan and the northern third of lower Michigan is minimal.
- For the middle third of lower Michigan and for SE lower Michigan, I'd say the probability is about a 1 on a scale of 5.
- For southwest & south central lower Michigan (Allegan, Barry, Eaton and Ingham south to the state line), I'd say the probability is about a 2 on a scale of 5. For the Lansing and Jackson area, the greatest severe weather risk might prove to be the midday hours of Monday. For far SW lower Michigan, the greatest severe weather risk might prove to be early evening on Monday.
- I think the SPC's severe wind outlook for Monday & Monday Night includes far too much of Michigan in the 30% to 44% risk zone, and the fact eastern Illinois is only shaded in the 15% to 29% zone is completely absurd.

I'm not impressed by the tornado risk anywhere in Michigan, with the possible exception of the counties along the MI/IN line. Even there, I'm thinking anything above an EF-1 is very unlikely.

Hail risk is underwhelming, but if we see any, it would more likely be with any midday storm activity.

Severe wind risk would be on the order of 58 mph to 65 mph mostly.

By tomorrow morning, I suspect we'll see some of Michigan downgraded by the Storm Prediction Center from a level 2 risk (slight) to a level 1 risk (marginal), and I suspect we'll see much of Indiana and much of Illinois upgraded to a level 3 of 5 risk (enhanced).

It also would not surprise me to see the Indiana border counties and possibly Van Buren, Kalamazoo and Calhoun Counties included in the level 3 risk. If it were me, I'd probably include Berrien and Cass in the level 3 risk and keep St. Joe, Branch, Van Buren, Kalamazoo and Calhoun in the level 2 risk, assuming overnight model runs don't change substantially from what I summarized above.

[MWmetalhead]

Environment Canada seems to think large hail and damaging winds are possible across Lambton, Kent and Essex Counties from now until 2AM.

I disagree.

[bmw]

Look at the impact the filtered sunlight over the past 2 weeks has had on the Great Lakes Surface temperatures.

Lake Huron hit the hardest, down from a peak of 70.6 degrees F to only 62.6 degrees F nine days later.
Lake Ontario down from 73.6 F to 66.5 F
Lake Superior is a mere 47.5 degrees right now. It was 59.1 degrees at this time last year.

https://apps.glerl.noaa.gov/coastwatch/ ... 1024_3.dat

[MotorCityRadioFreak]

Environment Canada seems to think large hail and damaging winds are possible across Lambton, Kent and Essex Counties from now until 2AM.

I disagree.

Looks like Hamilton, Ontario did get hit. I don’t think that is in those counties.

Most important question, did NWS fix Pontiac radar?

[MWmetalhead]

Hamilton is a good 150 miles east of the areas I mentioned.

Yes, at least for now, DTX radar is working properly.

The SPC upgraded Illinois and Indiana to a level 3 risk, as expected, and surprisingly, areas along & south of a Ludington, to Alma, to Detroit line were also upgraded.

I've not had a chance to review overnight model data.

[MWmetalhead]

CAPE remains on the flimsy side for lower Michigan in most of the model data I just reviewed, but bulk shear has intensified, especially for this evening. I think that's what has the SPC nervous.

I do still think the best chance for severe weather is in the Chicago area.

I think the slight risk zone indicated by the SPC goes too far north (I'd end it at roughly M-55), and I also think the enhanced risk zone covers too much of lower Michigan (my zone would be south & west of a Holland to Coldwater line). So, my slight risk and enhanced risk zones have expanded versus what I indicated yesterday afternoon but are not as bullish as the official SPC outlook.

Based on bulk shear, a few wind gusts to 75 mph now cannot be ruled out, especially in that Holland to Coldwater & points southwest corridor I mentioned.

[MWmetalhead]

I don't forecast for the U.P. generally, but it's worth mentioning some nasty storms are crossing through Gogebic and Ontonagon Counties this morning.

I'm far SW lower Michigan, another nasty cell is moving through Van Buren and Cass counties right now.

[MWmetalhead]

The SPC completely failed to issue weather watches for the Milwaukee and Chicago Metro areas prior to the arrival of massive super cellular storms this morning.

Chicago belatedly was finally placed under a watch moments ago (same WW that includes much of western and central lower Michigan).

The director of the SPC should be fired immediately!

The local NWS offices in WI and IL did a good job of issuing warnings thankfully.

These vicious storms moved over areas that just 12 hours ago were in a marginal risk outlook for today, so many folks were likely caught off guard.

[Rate This]

The SPC completely failed to issue weather watches for the Milwaukee and Chicago Metro areas prior to the arrival of massive super cellular storms this morning.

Chicago belatedly was finally placed under a watch moments ago (same WW that includes much of western and central lower Michigan).

The director of the SPC should be fired immediately!

The local NWS offices in WI and IL did a good job of issuing warnings thankfully.

These vicious storms moved over areas that just 12 hours ago were in a marginal risk outlook for today, so many folks were likely caught off guard.

They’ve maybe had a tornado west of Chicago and there is a confirmed extremely dangerous tornado (it doesn’t say large for some reason) in the Appleton, WI area right now… they look real nasty overall. I see that there is a severe thunderstorm watch as far east as Lansing now. The storms look like they are traveling on an angle enough to get to us later, at least the northern portion.

[MWmetalhead]

Even if Appleton doesn't get a tornado, they'll probably get widespread destructive straight line winds damage and hail to golf ball size or larger. That is a violent storm for sure!

Storm movement will turn SE as they approach Michigan. I think Lake Michigan will cause the storms to weaken somewhat. The environment for storms, if the model data is correct, isn't as favorable over Michigan as it is over Wisconsin, NE Illinois and NW Indiana.

[MWmetalhead]

The middle part of the storm cluster, midway between Milwaukee and Muskegon, looks much weaker than earlier.

I think Benton Harbor to South Bend is at greatest risk of seeing widespread damage from storms this afternoon.

Some spotty severe weather could occur from the cluster moving ashore in the Silver Lake area. That segment of storms could reach portions of Kent County eventually.

This is going to be a prolific severe weather event for Chicagoland.

[MWmetalhead]

The storms as they've moved into western lower Michigan have weakened a great deal. Everything is just "garden variety" at the moment.

[MWmetalhead]

Nearly all of lower Michigan has been downgraded to a slight risk by the SPC.

Only the SW tip of the state remains in the enhanced risk outlook.

I think much of the slight risk area in Michigan should be marginal at this point.

Only the Indiana border counties + Hillsdale remain under a severe thunderstorm watch.

[MWmetalhead]

The NWDS in Grand Rapids over hyped today's severe weather threat. This is why many people do not take storm forecasting seriously.

https://www.weather.gov/grr/weatherstory