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Winter 2021-22 Short/Medium Range Discussion

Chicago Storm

By Chicago Storm,
in Lakes/Ohio Valley

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ILSNOW

ILSNOW

Posted
Posted

Great  Izzi writeup (excerpts) 

Textbook La Nina pattern in place across the country and likely
to continue through the long term period with a powerhouse jet
stream, progged at times to exceed 200kt at 250 mb, separating
record breaking cold over the Pacific Northwest and southwestern
Canada from record heat over the southeastern U.S. Over the past
week or so long and then medium range models have been advertising
a gradual southward shift of the jet stream and storm track,
placing our area under the gun for more active, and potentially
wintry weather, during the long term period.
The timing differences among the various models have shrunk
considerably with precip expected to move into southern CWA
shortly after 12z Tuesday and then spread quickly north, likely
reaching the IL/WI border by around 18z. Unfortunately there
remain meaningful differences in thermal profiles Tuesday, with
the GEM and NAM both on the warm end of the spectrum and the ECMWF
on the cold end with the GFS sandwiched between. In the GEM/NAM
scenario, a brief period of wintry mix would quickly change to all
rain with little or no accumulation. The ECMWF holds onto a
deeper cold air mass longer and allows for a period of
accumulating snow Tuesday roughly north of I-80 with the most
significant accums north of I-90. Conceptually, a
weakening/filling surface low would be less effective in
dislodging low level cold air, which would lend a bit of credence
to the EMCWF solution suggesting a quick couple inches of snow
will accumulate, mainly northwest of I-90 Tuesday.
The hyper active, La Nina fueled Pacific jet is progged by medium
range guidance, which is in remarkably good agreement at this
distance, to develop a classic Panhandle to lower Great Lakes
strong storm late Friday into Saturday. If this system
materializes as advertised, it would have the potential to produce
a significant winter storm with heavy snow and strong winds
Friday night into Saturday somewhere in the Midwest. Our area is
certainly in the "cone of uncertainty" with this system and it
will bear close watching over coming days. It`s worth noting
that at this time range it isn`t the slightest bit uncommon for
there to be dramatic changes in model guidance in both the track
and strength of a potential storm systems, so it is way too early
to place any stock in any particular model`s current forecast
track or intensity, let alone their snowfall output. The primary
message this distance is: stay tuned, it could get messy next
weekend somewhere in the region.
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Baum

Baum

Posted
Posted
2 hours ago, ILSNOW said:

Great  Izzi writeup (excerpts) 

Textbook La Nina pattern in place across the country and likely
to continue through the long term period with a powerhouse jet
stream, progged at times to exceed 200kt at 250 mb, separating
record breaking cold over the Pacific Northwest and southwestern
Canada from record heat over the southeastern U.S. Over the past
week or so long and then medium range models have been advertising
a gradual southward shift of the jet stream and storm track,
placing our area under the gun for more active, and potentially
wintry weather, during the long term period.
The timing differences among the various models have shrunk
considerably with precip expected to move into southern CWA
shortly after 12z Tuesday and then spread quickly north, likely
reaching the IL/WI border by around 18z. Unfortunately there
remain meaningful differences in thermal profiles Tuesday, with
the GEM and NAM both on the warm end of the spectrum and the ECMWF
on the cold end with the GFS sandwiched between. In the GEM/NAM
scenario, a brief period of wintry mix would quickly change to all
rain with little or no accumulation. The ECMWF holds onto a
deeper cold air mass longer and allows for a period of
accumulating snow Tuesday roughly north of I-80 with the most
significant accums north of I-90. Conceptually, a
weakening/filling surface low would be less effective in
dislodging low level cold air, which would lend a bit of credence
to the EMCWF solution suggesting a quick couple inches of snow
will accumulate, mainly northwest of I-90 Tuesday.
The hyper active, La Nina fueled Pacific jet is progged by medium
range guidance, which is in remarkably good agreement at this
distance, to develop a classic Panhandle to lower Great Lakes
strong storm late Friday into Saturday. If this system
materializes as advertised, it would have the potential to produce
a significant winter storm with heavy snow and strong winds
Friday night into Saturday somewhere in the Midwest. Our area is
certainly in the "cone of uncertainty" with this system and it
will bear close watching over coming days. It`s worth noting
that at this time range it isn`t the slightest bit uncommon for
there to be dramatic changes in model guidance in both the track
and strength of a potential storm systems, so it is way too early
to place any stock in any particular model`s current forecast
track or intensity, let alone their snowfall output. The primary
message this distance is: stay tuned, it could get messy next
weekend somewhere in the region.

the entire LOT office will have to do damage control on his hype. Good news  is with it being 7 days out his damage is negligible and possible. When he goes "rogue" within 24 hours it's much more problematic. 

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hlcater

hlcater

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1 minute ago, Chicago Storm said:

PNA/SE ridge is still amped at that point. Doesn't trend downward until after that period.

There's quite a lot of cold air/higher pressures to the north of the system in Canada pressing down. Think that suppresses the system at least some. The EC depiction from earlier today seemed like the most likely outcome to me.

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Chicago Storm

Chicago Storm

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There's quite a lot of cold air/higher pressures to the north of the system in Canada pressing down. Think that suppresses the system at least some. The EC depiction from earlier today seemed like the most likely outcome to me.

Depends on the state of upstream NAO blocking and PV lobe location at the time. Any solution is really plausible at this time.


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Baum

Baum

Posted
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Fairly benign board reactions from the overnight runs outside of the usual "it's a rainer" or "it'll be a suppressed POS" crowd despite the fact we are days away from having any real clue. Nevertheless, despite the LOT futility record and the wailing and gnashing of teeth that this winter will suck it seems we have the potential for major panhandle hooker to track perhaps two weeks later than many would like but right in time for the New Year which has occurred many times before. So winter tracking season has officially begun IMBY really not much later than many years before. LOT concurs:

 "CONSIDERABLE QUESTIONS REMAIN WITH THE EXACT TIMING AND   
TRACK OF THIS POTENTIAL STORM SYSTEM, AND THIS WILL PLAY A MAJOR   
ROLE IN THE LOCAL IMPACTS THE AREA EXPERIENCES. THIS BEARS CLOSE   
WATCHING OVER THE NEXT SEVERAL DAYS AS IT IS LIKELY TO RESULT IN A  
SIGNIFICANT PERIOD OF WINTER WEATHER SOMEWHERE ACROSS THE   
MIDWEST. ANYONE WITH TRAVEL PLANS ACROSS THE REGION THIS WEEKEND   
SHOULD PAY CLOSE ATTENTION TO THE FORECAST. "

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Baum

Baum

Posted
Posted

and of note regarding the record late measurable snow at LOT and tomorrow's nuisance event:

 FINALLY, FOR GENERAL WEATHER/CLIMATE DATA INTEREST,   
CHICAGO’S REMARKABLE MEASURABLE SNOW DROUGHT HAS A INCREASINGLY   
GOOD CHANCE OF ENDING WITH THIS EVENT.   
  
CASTRO 

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