11/13/05: WIND EVENT / NOVEMBER GALE

[Robert Dewey]

Okay, still quite a few hours away... But the NAM has come into agreement with the GFS and other medium range models in a big way. It has the low deepening on the order of 12-14MB over 12 hours, down to 980MB or slightly lower, with a very tight pressure gradient at the SFC thanks to +1030MB highs on each side of the low... In the low levels, NAM shows widespread 60-80KNTS at 850MB (haven't checked mixing layer heights / thetaE x-sections, etc. yet), but the SFC plot does indicate sustained winds of 40KNTS for most of northern WI and northern lower MI...

 

[Joel Wright]

Yup, looks like a pretty good high wind event in WI and MI. It's bombing too late again to give the rest of the midwest anything too exciting.

 

[Robert Dewey]

Just got done looking at NAM BUFKIT data and cross sections for various locations... General mixing layer heights are around 5K FT after the front passes, and wherever the strongest low level wind sets up is where things will get pretty bad. For instance, NAM shows 70-75KNTS well within the mixing layer at APX (Alpena, MI)... That's absolutely beyond impressive, that would translate into frequent gusts of 80-90MPH if the NAM has it's way! Basically, a mixing layer of 5K FT taps into the 850MB level, so what you see on that map is the gust potential for certain areas that can mix high enough (northern lower MI, WI, etc.). Talk about an inland hurricane!

Further away from the low, at DTX (Detroit/Pontiac, MI), things are a more "reasonable" with 45-55KNTS within the mixing layer... That would translate into solid advisory to low end warning criteria winds of 50-60MPH (gusts).

And just some info, Joel... I wouldn't discount your area quite yet. It all depends on where exactly the upper level low winds up - while the models agree that it WILL wind up, WHERE it winds up is still a question mark. The latest 00Z GFS actually digs the trough a bit deeper, and thus the system is about 25 MI further south.

 

[Robert Dewey]

...The Legend Lives On...

NAM continues to show a widespread damaging wind across the Great Lakes, though the trough now extends a bit further south than the 00Z run. The 12Z BUFKIT isn't in yet, so I am using cross sections to analyze the situation. But, the 06Z NAM BUFKIT did show an increase in winds across the GRR and DTX areas, with a forecast of 50-60KNTs rather than the 45-55KNTS previously.

Latest NAM and cross sections show most of MI and southern/central WI mixing well up into the 5-6K FT layer, or roughly 850-800MB, with very intense CAA taking place. At that level, winds of 60-70KNTS will be widespread, with pockets of 70-80KNTS above the lakes... At the SFC, that would translate into widespread and frequent 60-80MPH gusts, with 80-90MPH possible over the lakes and lake shore areas. That would rival or exceed the storm that occured back in November of 1998, where Mackinac reports wind gusts of up and over 90MPH!

The best pressure fall/rise couplet slides across northern lower MI, where the strongest winds will be likely given the combination of CAA, +70KNTS in the mixing layer, and a very strong pressure fall/rise couplet previously mentioned.

This looks like it could be quite a damaging event for areas of the Great Lakes, and if it materializes it could be by far the worst synoptic wind event in quite some time.

____

EDIT: Here are some maps...

Cross section of Theta-E and winds (mixing layer height):
http://www.waveformpc.com/pics/cross_section.gif
http://www.waveformpc.com/pics/cross_section2.gif

And a map of the 4-6K FT average wind speed:

 

[Tim Gonyo]

Looks like southern WI and most of Lower Michigan is gonna get nailed!

 

[Robert Dewey]

DTX:

A HIGH WIND WATCH IS IN EFFECT ACROSS THE NORTHERN CWA AND HEADLINES WILL LIKELY BE NEEDED FOR THE SOUTH HALF AS WELL.

Sounds like a good idea to me... Still 18-24 hours away, so all of the details may not be 100 percent accurate, but I think it's safe to say someone will get some extremely high winds tomorrow.

 

[Andy Wehrle]

Inland hurricane is right. And we thought it was windy last Wednesday. :shock:

Edit: La Crosse's AFD says it all:

SO TO SUM IT ALL UP....A SEVERE THREAT...THEN HIGH WINDS...THEN A POSSIBLE ACCUMULATING SNOW IN THE NEXT 3-4 DAYS. MUST BE NOVEMBER.

 

[Robert Dewey]

Latest 18Z NAM looks like it initialized a bit too weak with the SFC low (993MB, versus 18Z obs of 991MB)... Comparing the 21Z/3HR NAM SFC fields to the 20Z SFC obs, NAM has 995MB over areas that are already at or below 990MB... Unless those stations bump up to 995MB over the next hour, then I would have to say the NAM may be too weak with this system...

 

[Robert Dewey]

00Z NAM also looks a bit weak with the initialization... The RUC seems to be doing a better job, and puts the low at around 982MB by 12Z tomorrow over western Lake Superior. Also of interest, DVN is currently reporting wind gusts of 45-50KNTS behind the cold front, with widespread 35KNT winds elsewhere... Otherwise, things still look on track for a significant damaging wind event tomorrow afternoon and evening.

Here is the data from my weather station... Don't be surprised if you see extreme values (or abnormally low values; like every METAR station is reporting 30KNTS and I'm only reporting 10-15KNTS), as I can't vouch for it's accuracy. I'll probably report after the storm is over as to whether or not it was accurate.

Weather Station - 15 MI EAST OF NWSFO DTX

I'll see if I can get my webcam up in a bit to so that I can stream live data tomorrow via the internet (at 256k).

 

[Andy Wehrle]

***Wind Advisory upgraded to High Wind Warning for parts of western Minnesota and northwestern Iowa. Sustained winds 40-50 mph are expected with gusts to 60 mph***

Bomb-o-genesis seems to be right on track with most stations near the cyclone center reporting sub-990 mb pressures. Lowest pressures I can find are at St. Cloud, MN at 988.5 mb (29.16" HG) and Brainerd, MN at 987.9 mb (29.15" HG). Interestingly, both have rather calm winds at 3 and 10 MPH, respectively. I guess you could call this the "eye of the storm".

 

[Joel Wright]

...Also of interest, DVN is currently reporting wind gusts of 45-50KNTS behind the cold front....

I measured a peak wind gust of 49mph as the band of thunderless heavy showers came through. It blew hard for quite awhile. That was my highest gust of the year so far.

It looks like the strongest winds will spread across souther MN into the northern half of WI, and then into far northern lower MI and the UP.

 

[Robert Dewey]

Found this pretty interesting:

Plenty of lightning in and around the center of the low... Lowest pressure I can see now is 987MB, being reported by several stations. Looks like a good portion of WI, almost all of lower MI, and the sections of the U.P. will get slammed by very intense winds. The U.P. might actually be saved given their location relative to the low (too close to the center of circulation). 03Z RUC showing 800MB winds (the top of the mixing layer at most locations mentioned) of 65KNTS by 15Z with a 984MB low. We shall see...

 

[Robert Dewey]

Here is my webcam server: http://67.149.108.24/

I believe it uses Java, and it's streaming at 256k so you'll probably need a broadband connection to view it. I've never used this webcam before, so it might go out, fall off the shelf, etc.. :lol:

 

[Joel Wright]

After the 49.2mph gust during the line of convection last evening, my record for the gradient wind since was 47.7mph around 6am this morning. It looks like the stronger winds expanded a bit further south than what I expected yesterday.

It looks like the winds are getting ready to really kick up in MI..

 

[Robert Dewey]

My weather station gets a data spike every now and then of >90MPH. I don't know what the deal is, but ignore them... :x

EDIT: Hmm... That's odd. It seemed to report a 55MPH wind gust fairly accurately. Based on other sites around me that are seeing 40-45MPH gusts, 55MPH doesn't seem too far off (considering my temporal resolution is better). My average gust speed is around 35MPH, right on target with NWS METAR sites...