Jump to content
  • Member Statistics

    17,609
    Total Members
    7,904
    Most Online
    NH8550
    Newest Member
    NH8550
    Joined

November 6th Rain/Wind/Severe Event


HillsdaleMIWeather

Recommended Posts

The rate of surface low deepening as advertised on the GFS is pretty high end for this region of the country.  Not Cleveland Superbomb like (what is) but certainly in line with some of the great fall systems of the past.  But much of the bombing occurs as the surface low is about to head out of the US or after it's already gone.

Link to comment
Share on other sites

  • Replies 148
  • Created
  • Last Reply

The rate of surface low deepening as advertised on the GFS is pretty high end for this region of the country. Not Cleveland Superbomb like (what is) but certainly in line with some of the great fall systems of the past. But much of the bombing occurs as the surface low is about to head out of the US or after it's already gone.

Even with rapid exit as system deepens, still an impressive wind signal on the GFS. Snapshots of 925 mb winds from 12z and 15z Friday.

post-3997-14465265474.png

post-3997-14465265744.png

Soundings over northern IL at 12z already show mixing to 900 mb while 925 mb winds are ~40-45 kt. And the signal is even more impressive over MI at 15z. Inversion is gone on soundings with mixing to 900 mb which would tap 50+ kt winds. Still 35-40 kt at 925 mb over nrn IL at that time.

Link to comment
Share on other sites

Even with rapid exit as system deepens, still an impressive wind signal on the GFS. Snapshots of 925 mb winds from 12z and 15z Friday.

attachicon.gifScreenshot_2015-11-02-22-52-21.png

attachicon.gifScreenshot_2015-11-02-22-53-44.png

Soundings over northern IL at 12z already show mixing to 900 mb while 925 mb winds are ~40-45 kt. And the signal is even more impressive over MI at 15z. Inversion is gone on soundings with mixing to 900 mb which would tap 50+ kt winds. Still 35-40 kt at 925 mb over nrn IL at that time.

 

 

If I had my choice, I'd like to slow this down some to have the strongest winds aloft come over more during the daylight hours in case there's a weak inversion near the surface in the early morning.  But it's questionable how much of an inversion there will be as the low levels should remain pretty well mixed overnight Thursday.

Link to comment
Share on other sites

The 0z GFS lifts the low north just a little bit too quickly for Ohio/Indiana at least IMO...although it's close. Although frontal timing in the afternoon would be preferred, it's not as necessary in strongly forced and high shear situations when CAPE is usually minimal anyways...just need to get the low to bomb before it's moving into Canada.

Link to comment
Share on other sites

Anywhere from Illinois to Indiana? Or, further south? 

That really depends on how quickly the surface low bombs and how quickly it tracks northeast. I'd rather be farther east and probably north in this instance, but we still have almost 3 days to slow down the low some or deepen it quicker.

Link to comment
Share on other sites

The 0z GFS lifts the low north just a little bit too quickly for Ohio/Indiana at least IMO...although it's close. Although frontal timing in the afternoon would be preferred, it's not as necessary in strongly forced and high shear situations when CAPE is usually minimal anyways...just need to get the low to bomb before it's moving into Canada.

Agreed, especially not looking great down here in Cincinnati. At 6am we have 60kts at 4,200 ft, but less than 200 CAPE and less than stellar frontal timing as you mentioned.

Sent from my XT1060 using Tapatalk

Link to comment
Share on other sites

There she is. 

 

"...MIDWEST TO MID-SOUTH...

A CONTINUATION OF DIURNALLY ENHANCED CONVECTION FROM FARTHER W OR A
SEPARATE AREA OF EVENING/OVERNIGHT CONVECTION SHOULD ULTIMATELY
ACCOMPANY THE ACCELERATING FRONT. WHILE SURFACE-BASED INSTABILITY
WILL LIKELY BE MINIMAL N OF THE LOWER OH VALLEY WITH MOIST-ADIABATIC
THERMODYNAMIC PROFILES...THE INCREASINGLY NEGATIVE TILT OF THE
SHORTWAVE TROUGH IN CONJUNCTION WITH A 100-KT 500-MB SPEED MAX COULD
SUPPORT A FAST-MOVING SQUALL LINE WITH AN ACCOMPANYING DAMAGING-WIND
RISK. IN THE LOWER OH VALLEY TO MID-SOUTH...A NOCTURNAL TORNADO RISK
MAY ALSO DEVELOP GIVEN THE POTENTIAL FOR AT LEAST MEAGER
SURFACE-BASED INSTABILITY AND STRONG LOW-LEVEL SHEAR. WITH SUCH
LARGE SPREAD IN GUIDANCE REGARDING THE DEGREE OF CYCLOGENESIS...IN
ADDITION TO THE LIMITED INSTABILITY...WILL DEFER ON A POSSIBLE
SLIGHT RISK."

post-13724-0-84241900-1446540674_thumb.g

Link to comment
Share on other sites

Agreed, especially not looking great down here in Cincinnati. At 6am we have 60kts at 4,200 ft, but less than 200 CAPE and less than stellar frontal timing as you mentioned.

Sent from my XT1060

If we can manage 65kt plus at 850mb ahead of the cold front, I'm not as worried about frontal timing. The 6z GFS held steady with the frontal timing but ramped up wind fields some. The NAM does have a few hundred J/KG of CAPE getting into OH FWIW. I'd probably lean on the NAM for instability over the GFS in situations like this. My main concern is getting the low to really strength before the cold front pushes through, or else the wind fields won't suffice for a severe QLCS.
Link to comment
Share on other sites

Here's a list of highest November PWATS for various locations, and 12z GFS/NAM progged max PWAT values (at either 00z Fri or 12z Fri, depending on location).  The ILN record appears to be in most danger of falling.

 

May bump this in a couple days to see where things stand.

 

 

APX:

 

record:  1.20", 11/1/2013

GFS:  1.31"

NAM:  1.27"

 

 

DVN:

 

record:  1.39", 11/18/2004

GFS:  1.26"

NAM:  1.40"

 

 

ILX:

 

record:  1.53", 11/2/1972

GFS:  1.47"

NAM:  1.50"

 

 

DTX:

 

record:  1.52", 11/6/1977

GFS:  1.52"

NAM:  1.54"

 

 

ILN:

 

record:  1.58", 11/9/2000 and 11/2/1972

GFS:  1.82"

NAM:  1.70"

Link to comment
Share on other sites

At least it's an interesting system to try and forecast if not frustrating. We have terrible lapse rates keeping instability down, but strong dynamics including 30+ kts of 1km shear. It looks like there could be strong synoptic scale lift owing to the vorticity max sweeping through, but also mesoscale lifting mechanisms owing to some mid level frontrogenesis to drive us all insane as well. At least we'll all have the opportunity to hone our skills!

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

  • Recently Browsing   0 members

    • No registered users viewing this page.

×
×
  • Create New...