Jump to content
  • Member Statistics

    17,589
    Total Members
    7,904
    Most Online
    LopezElliana
    Newest Member
    LopezElliana
    Joined

Christmas Grinch Storm Part 2


Chicago Storm

Recommended Posts

  • Replies 575
  • Created
  • Last Reply

Credit to tom. He was skeptical at 5pm. Worked the meteorology not only the modeling.

 

Yep, definitely deserves credit and his call sound like a safe bet at this point. He still stressed there could be snow bursts that could complicate travel. 

Fwiw the RPM spread snow further west than the 4km and 12km NAM.

Link to comment
Share on other sites

I had a funny feeling this storm was going to go this way.  It just didn't "feel" like a snow storm for this part of the subforum.  I mentioned a few posts back that I was figuring 1"-2" for around here, and that might pan out.  I have been reading posts here and looking at models when I could, and I have been waiting for the shift to the east, and the earlier run of the Euro, even though at the time, it was the outlier, I had a feeling it was on to something.  The other thing was that caveat that Alek pointed out in that AFD about the convection down near the Gulf Coast, and it's possible effect on this system. 

Link to comment
Share on other sites

Credit to tom. He was skeptical at 5pm. Worked the meteorology not only the modeling.

And this is not to slight anyone cause I'm sure most that followed this pain in the arse don't trust it.

 

Anyone else hear his last moment comment that we could be back in the 50's on Friday?

Link to comment
Share on other sites

I'd be careful with the snow maps as they could be too stingy farther west if the changeover happens faster than the 00z runs suggest.

 

The RGEM says, "What precipitation farther west?" Sharp cutoff over ORD land.

 

EDIT: Maybe you need to be in EASTERN Lake County to get in on the good stuff.

 

Link to comment
Share on other sites

I'd be careful with the snow maps as they could be too stingy farther west if the changeover happens faster than the 00z runs suggest.

 

I see what you're saying. So it's not necessarily less precipitation...just a matter of changeover time. Which, as we can tell, the NAM is changing it over much faster than the GFS.

Link to comment
Share on other sites

The RGEM says, "What precipitation farther west?" Sharp cutoff over ORD land.

 

EDIT: Maybe you need to be in EASTERN Lake County to get in on the good stuff.

 

attachicon.gifrgem_apcpn_ncus_12.png

 

 

 

Look at the snow map posted earlier in the thread

 

post-7389-0-81267800-1419392746.png

 

It looks awful if you're in IN, etc but that's still a pretty good amount of precip.  No way of knowing just how quickly the cooling process occurs but you gotta have precip to be in the game.

Link to comment
Share on other sites

IWX may need to consider throwing up advisories for their northwest and north central counties since it is a holiday, although it will be chump change to them, being in the lake belt.

Wondered about that. Might be wise to do so, or at least issue a SWS, since we seem to be in the middle of a shift...

Link to comment
Share on other sites

Very interesting cold weather thunderstorm setup unfolding in the Ohio Valley up thru Western NY and S Ontario tomorrow evening.  5% issued by SPC and NWS Buffalo had this to say......

LATEST NAM AND GFS RUNS CONTINUE TO DROP THE SHOWALTER INDEX DOWN TO
JUST BELOW 0C WITH MUCAPE OF AROUND 100J/KG FOR PARCELS ROOTED JUST
ABOVE THE SURFACE. BY SUMMER STANDARDS THIS INSTABILITY IS
NEGLIGIBLE...HOWEVER IN THE PRESENCE OF A STRONGLY FORCED COLD FRONT
IT MAY BE ENOUGH TO SUPPORT A LINE OF CONVECTIVE SHOWERS THAT MAY
PRODUCE THUNDER. 500MB WINDS EXCEED 100 KNOTS...WHICH IS AN OLD RULE
OF THUMB THRESHOLD FOR A COLD SEASON DERECHO IF A STRONGLY FORCED
ENVIRONMENT IS PRESENT. IF SUCH A CONVECTIVE LINE IS ABLE TO
DEVELOP...THE PRESENCE OF A VERY STRONG WIND FIELD IN THE MID LEVELS
MAY SUPPORT A RISK OF CONVECTIVELY GENERATED DAMAGING WIND GUSTS.
THESE SEVERE GUSTS WOULD BE MOST LIKELY WITH ANY SMALL SCALE BOWING
SEGMENTS THAT DEVELOP ALONG THE LINE...IF IT MATERIALIZES.

Link to comment
Share on other sites

Very interesting cold weather thunderstorm setup unfolding in the Ohio Valley up thru Western NY and S Ontario tomorrow evening.  5% issued by SPC and NWS Buffalo had this to say......

LATEST NAM AND GFS RUNS CONTINUE TO DROP THE SHOWALTER INDEX DOWN TO

JUST BELOW 0C WITH MUCAPE OF AROUND 100J/KG FOR PARCELS ROOTED JUST

ABOVE THE SURFACE. BY SUMMER STANDARDS THIS INSTABILITY IS

NEGLIGIBLE...HOWEVER IN THE PRESENCE OF A STRONGLY FORCED COLD FRONT

IT MAY BE ENOUGH TO SUPPORT A LINE OF CONVECTIVE SHOWERS THAT MAY

PRODUCE THUNDER. 500MB WINDS EXCEED 100 KNOTS...WHICH IS AN OLD RULE

OF THUMB THRESHOLD FOR A COLD SEASON DERECHO IF A STRONGLY FORCED

ENVIRONMENT IS PRESENT. IF SUCH A CONVECTIVE LINE IS ABLE TO

DEVELOP...THE PRESENCE OF A VERY STRONG WIND FIELD IN THE MID LEVELS

MAY SUPPORT A RISK OF CONVECTIVELY GENERATED DAMAGING WIND GUSTS.

THESE SEVERE GUSTS WOULD BE MOST LIKELY WITH ANY SMALL SCALE BOWING

SEGMENTS THAT DEVELOP ALONG THE LINE...IF IT MATERIALIZES.

 

Well that sure makes things more interesting. Check out those 500mb winds as the front passes. Nice momentum transfer as well.

 

YYZ forecast sounding off the 00Z NAM4km.

 

cnUWSjR.png

Link to comment
Share on other sites

Noticeable difference in placement of the rain/snow line between the NMM and ARW.  ARW is quicker with the changeover and appears to have more intense precip.  This is reason for folks like Tim and me (and maybe even Chicago) to not completely bail yet.  It's all going to come down to how intense that band of precip is and how soon it can force a changeover to snow.

 

 

post-14-0-81243300-1419398290_thumb.gif

Link to comment
Share on other sites

Testing this feature...

 

Partially out of boredom, partially out of desperation, I created an animation of RAP runs, 22z to 04z, all valid for 08z. Only conclusion(s) you might draw from this is a slowing down in progression of the low, and maybe even a nudge to the west, particularly in the final frame.

 

May have to click on the image to view animation.

post-12308-0-89120600-1419401171_thumb.g

Link to comment
Share on other sites

Exact location of the back edge of the precip shield still problematic.  I noticed that 20 out of 21 of the 21z SREF members produced over a quarter inch of precip at ORD while the 00z Euro looks like it's almost a shutout.  I'll be following what happens with that...would be a pretty bad SREF bust this close in.

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...