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I disagree with our weather forecasters on TV

Discussion pertaining to Detroit, Ann Arbor, Port Huron, and SW Ontario
jadednihilist
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Re: I disagree with our weather forecasters on TV

Post by jadednihilist » Wed Jul 28, 2021 7:57 pm

These storms are certainly taking a while to get organized. Part of the problem, as noted by the NWS offices in Milwaukee and Green Bay is smoke from western wildfires and clouds have blocked some sunlight from reaching the surface limiting some daytime heating. Smoke and dust isn't included in the forecast models.. it's just really computationally expensive to add aerosols into an already complex high resolution model.

The lack of heating has slowed destabilization with plenty of convective inhibition (CIN), which is essentially negative CAPE, over northern Wisconsin. There are still steep lapse rates aloft that has sparked elevated convection in Northern Wisconsin. The much higher CAPE in MN and IA shown in the SPC Mesoanalysis should be pushed northward within the next couple hours. This advection will interact with the powerful upper level winds and that's when things should really get going.

Image

This is the 850 mb level jet in blue pushing into Wisconsin later. At the nose of this jet is where we'll have enough converging low level air parcels to trigger deep convection noted the robust line.

Image

A significant wind event is still quite likely across Wisconsin this evening with downstream impacts across lower Michigan overnight.


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MWmetalhead
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Re: I disagree with our weather forecasters on TV

Post by MWmetalhead » Wed Jul 28, 2021 8:10 pm

I did see that Minneapolis was only 90 degrees around 2PM CT on a day where a high of 98 was forecast. Humidity also wasn't as bad as forecast, at least at the time. I'm too lazy to check what's happening there now.

I'm beginning to think the line will have more of a north to south movement, at least initially, which if true, would dramatically lessen impacts for Michigan, especially east of US 131.

The above thoughts only pertain to the damaging wind threat; I do think toward morning SE Michigan has a decent shot at shower and garden variety storm activity regardless.



km1125
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Re: I disagree with our weather forecasters on TV

Post by km1125 » Wed Jul 28, 2021 8:11 pm

I echo Fargo's comments.

Well, in the spirit of this thread, to be more appropriate, I bow-echo Fargo's comments!! :)



jadednihilist
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Re: I disagree with our weather forecasters on TV

Post by jadednihilist » Wed Jul 28, 2021 8:19 pm

hahah bow echo!

The SPC has decided to go with a high end severe thunderstorm watch with widespread wind gusts of 90+ mph expected.
Image


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MWmetalhead
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Re: I disagree with our weather forecasters on TV

Post by MWmetalhead » Wed Jul 28, 2021 8:26 pm

I think a lot more of NE Illinois should be in the enhanced or moderate risk zone.



jadednihilist
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Re: I disagree with our weather forecasters on TV

Post by jadednihilist » Wed Jul 28, 2021 8:40 pm

Should have the 00 UTC soundings online within the next hours. I'm very interested at seeing what they are showing. I'll update after I do some analysis.


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MWmetalhead
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Re: I disagree with our weather forecasters on TV

Post by MWmetalhead » Wed Jul 28, 2021 9:26 pm

The WI watch has been upgraded to a PDS watch. No derecho or bow echo yet, just a QLCS running in an east-west fashion with some very nasty discrete imbedded supercells.

Unless that line morphs into something that takes on more of a N to S configuration, or unless there's new development (very possible) I'm having a hard time seeing how more than just far western MI gets hit. Bigger threat for eastern half of the L.P. appears to be very heavy rainfall unfortunately.

78 degree dew point at Minneapolis right now!



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MWmetalhead
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Re: I disagree with our weather forecasters on TV

Post by MWmetalhead » Wed Jul 28, 2021 9:42 pm

If a bow echo or derecho forms, I think the genesis will be the nasty cell that extends from Rice Lake to Ladysmith, WI. I think it'll be 2a to 3a before the nasty stuff reaches US 131.



jadednihilist
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Re: I disagree with our weather forecasters on TV

Post by jadednihilist » Wed Jul 28, 2021 10:04 pm

I got a chance to look at the 00Z upper level analysis. Of note is the extremely impressive sounding over Minneapolis with SBCAPE at 6060 J/kg(!!) with 37 kt 0-1 km shear, 45 kt 0-6 km shear, and a super elongated hodograph resulting in storm relative helicity values at 392 m^2/s^2 (!!) from 0-1 km and 480 m^2/s^2 at 0-3 km. This explains the supercells that are firing near the MN/WI border... these could quickly produce quite a nasty tornado.

Downstream in Green Bay, the instability (at 1177 J/kg with 236 J/kg CIN) remains modest and the wind profile has more modest (but still sufficient for organized convection) low level shear at 19 kts (0-1km) with 57 kt 0-6 km shear. As the low level jet pushes eastward, that will both serve to destabilize the atmosphere across central and eastern Wisconsin and also increase storm relative helicity.

At the 500 mb level, there's a developing weak shortwave trough extending from Duluth to south/east of Hudson Bay. This shortwave will increase the upper support for the mesolow that eventually forms from this developing derecho.

Michigan impacts
I agree with MW that now that we know where convective initiation is occurring, the severe threat is shifting westward, with a much lower chance of seeing extreme weather across Metro Detroit. The corridor of strongest winds will move across much of Wisconsin, perhaps into SW lower Michigan, and Illinois and Indiana. Heavy rain is still a distinct possibility here, as well as some isolated damaging wind gusts -- but overall shouldn't be too extreme.

This system will gradually move eastward into the mid Altantic tomorrow, increasing the severe weather threat down there.


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Thunderstorm
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Re: I disagree with our weather forecasters on TV

Post by Thunderstorm » Wed Jul 28, 2021 10:22 pm

Grand Rapids Area Forecast Discussion UPDATE

ISSUED AT 1014 PM EDT WED JUL 28 2021

I THOUGHT IT GOOD TO SAY SOMETHING ABOUT THE TIMING OF THE STORMS
TONIGHT. THERE IS AN AREA OF STORMS ORGANIZING OVER NORTHERN
WISCONSIN. THE STORMS ARE EXPECTED TO BECOME BETTER ORGANIZED AND
MOVE INTO OUR NORTHWEST CWA NEAR BIG SABLE POINT NEAR OR AFTER
MIDNIGHT. THE STORMS WILL CONTINUE TO MOVE SOUTH AND STRENGTHEN
IN RESPONSE TO A STRENGTHENING LOW LEVEL JET AND MIX LAYER CAPES
NEAR 2000 TO 2500 J/KG. IT SEEMS THE GREATEST THREAT FOR DAMAGING
WINDS WOULD BE SOUTH OF LITTLE SABLE POINT AND WEST OF A LINE FROM
BIG RAPIDS TO JACKSON. THERE DOES SEEM TO BE THE POTENTIAL FOR
WIND GUSTS OVER 70 MPH WITH SOME THE BOW ECHOS EXPECTED TO MOVE
INTO THIS AREA EARLY THURSDAY MORNING.

ALSO LOCALLY VERY HEAVY RAIN AND LOCALIZED FLOODING STILL SEEMS TO
BE AN ISSUE WITH THIS STORMS. SO OF OUR HI-RES MODELS ARE SHOWING
MORE THAN 2 INCHES OF RAIN FALLING IN LESS THAN 6 HOURS (REALLY
LESS THAN 3 HOURS). THE HEAVIEST RAIN WOULD BE IN THE SAME AREA AS
THE STRONGEST WINDS ARE POSSIBLE.



DISCUSSION
(THIS EVENING THROUGH NEXT WEDNESDAY)
ISSUED AT 800 PM EDT WED JUL 28 2021

WE REMAIN ON TRACK FOR POTENTIALLY DESTRUCTIVE THUNDERSTORM WIND
GUSTS LATE TONIGHT WITH A HEIGHTENED RISK FOR TREE AND STRUCTURAL
DAMAGE ALONG WITH A LARGE NUMBER OF POWER OUTAGES. THE LATEST SPC
MESOANALYSIS SUGGESTS MLCAPE VALUES OF 2000-3000 J/KG EVEN INTO
THE 03Z-05Z TIMEFRAME FROM MKG TO GRR TO BTL AND POINTS WESTWARD
WITH LITTLE TO NO MLCIN. THAT WILL HELP ALLOW THE STRONGEST
THUNDERSTORM WINDS TO MIX DOWN TO THE SURFACE WITH LITTLE TO NO
RESISTANCE.

MANY OF THE LAST SIX HOURS OR SO OF THE HRRR RUNS HAVE INDICATED
POCKETS OF 90+ MPH WIND GUSTS MOVING INTO OUR LAKESHORE COUNTIES
WITH THESE STORMS TONIGHT. SIGNIFICANT EFFECTIVE SHEAR VALUES OF
50-60 KTS ARE PROJECTED, HELPING AID OR INCREASE STORM INTENSITY.
ISOLATED TORNADOES OR EMBEDDED QLCS TORNADOES ARE STILL ON THE
TABLE AS WELL, BUT THE THREAT IS LIKELY DWARFED BY THE STRAIGHT
LINE WIND DAMAGE RISK GIVEN THE AREAL SCOPE AND INTENSITY THAT MAY
BE FEATURED WITH THESE STORMS TONIGHT. AS FOR TIMING, WE BELIEVE
THAT AFTER 11PM STILL LOOKS ON TRACK FOR OUR NW REGION, THEN INTO
THE EARLY MORNING HOURS FOR THE MAJORITY OF WESTERN, CENTRAL, AND
SOUTHERN LOWER MI.

THERE MAY ALSO BE AN AREAL FLOOD RISK DEPENDING ON POSSIBLE
REDEVELOPMENT OF SHOWER AND THUNDERSTORM ACTIVITY BEHIND THE MAIN
COMPLEX OF STORMS. SOME AREAS COULD GET 2"-4" OF RAIN IF THIS
OCCURS, LEADING TO SOME PONDING OF WATER ON ROADS PRIOR TO
SUNRISE.



jadednihilist
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Re: I disagree with our weather forecasters on TV

Post by jadednihilist » Wed Jul 28, 2021 10:23 pm

Grand Rapids NWS remains quite bullish on SW MI seeing extreme impacts overnight.

https://mesonet.agron.iastate.edu/wx/af ... 2107290209

I am skeptical given the current storm motion. It seems that they're banking on the west-to-east low level jet at 850 to pushes the storms in a more easterly direction. There's also a decent eastward component to the winds at 700 mb, too.

Edit: Thanks for posting the Grand Rapids discussion, Thunderstorm. They're definitely banking on the LLJ.


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Thunderstorm
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Re: I disagree with our weather forecasters on TV

Post by Thunderstorm » Wed Jul 28, 2021 11:08 pm

Movement on those storms in western Wisconsin are south-southeast.

Latest MD
https://www.spc.noaa.gov/products/md/md1380.html



Thunderstorm
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Re: I disagree with our weather forecasters on TV

Post by Thunderstorm » Thu Jul 29, 2021 12:25 am

NWS Grand Rapids Update:

.UPDATE...
ISSUED AT 1215 AM EDT WED JUL 29 2021

IT STILL LOOKS LIKE STRONG TO SEVERE STORMS ARE POSSIBLE IN OUR
SOUTHWEST CWA LATE TONIGHT OR REALLY TOWARD SUNRISE THURSDAY.
CURRENTLY THERE IS A LINE OF STORMS MOVING MORE SOUTH THAN EAST
OVER NORTH CENTRAL WISCONSIN. THE LATEST RAP MODEL SUGGESTS THE
LOW LEVEL JET WILL REDEVELOP FARTHER EAST AROUND 3-4 AM OVER
CENTRAL LAKE MICHIGAN.

AS THAT HAPPENS, CONVECTION SHOULD
DEVELOP OVER OUR NW CWA AFTER 4 AM AND THAT NOW APPEARS TO BE
WHAT WILL BE OUR PRIMARY EVENT. THIS MAY SUGGEST TOO THAT
THIS MAY BE MORE OF RAIN EVENT THAN A DAMAGING WIND EVENT. WE WILL
CONTINUE TO MONITOR THIS.



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MWmetalhead
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Re: I disagree with our weather forecasters on TV

Post by MWmetalhead » Thu Jul 29, 2021 12:51 am

Nice to see the NWS is finally recognizing what I stated a few hours ago (Jaded mentioned many of these same points, too):
-Movement is more southward than eastward
-Serious questions exist as to eastern extent of storms
-More & more likely severe activity misses most of Michigan. For Michigan to see significant SVR, new storm development will likely need to occur.
-Focus is increasingly on a heavy rain event more so than a SVR wind threat.

I do note what appears to be some enhanced elevated instability near Green Bay, well behind what is currently the main line. Consistent lightning on radar now for 90+ minutes up that way. As the LLJ maxim heads east, perhaps that'll spark expansion and strengthening of that activity, but that's a big "if" at this point.



Thunderstorm
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Re: I disagree with our weather forecasters on TV

Post by Thunderstorm » Thu Jul 29, 2021 2:28 am

Severe Thunderstorm Watch
for Allegan, Berrien, Cass, Kalamazoo, St. Joseph, Van Buren Counties
https://www.spc.noaa.gov/products/watch/ww0400.html



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