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January Medium/Long Range Discussion

WinterWxLuvr

By WinterWxLuvr,
in Mid Atlantic

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brooklynwx99
brooklynwx99

It looks like we are finally entering an extremely favorable pattern starting around the 14-16th. The Pacific jet retraction will take place during that time, and the +PNA/-EPO will be able to strengt

WxUSAF
WxUSAF

Ok, wanted to make a post showing the impact of the ocean storm on ~Friday to the environment afterward and hence the possibility of a Sunday/MLK day storm.  Helpfully, the 3 big globals provided a ve

psuhoffman
psuhoffman

I know this is long but I’m pretty busy this weekend so this is my one deep analysis contribution for the weekend   But first man that was some epic entertainment in here earlier.  Vice hiatus

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snowmagnet

snowmagnet

Posted
Posted
2 hours ago, benjammin said:

Those tiny maps in the Washington Post and Star. Of course dialing 936-1212 but the biggest thing was when Bob Ryan said it was going to snow a lot because he was usually conservative and right. In January 96 when he forecasted 1-2 feet before a flake had fallen I knew we were going to get nailed.

Sent from my motorola edge plus using Tapatalk


 

I have distinct memories of watching Bob Ryan’s forecasts and loved it when he had to up his snow totals. He was always so conservative with his snow forecasts. 

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Warm Nose

Warm Nose

Posted
Posted
2 hours ago, benjammin said:

Those tiny maps in the Washington Post and Star. Of course dialing 936-1212 but the biggest thing was when Bob Ryan said it was going to snow a lot because he was usually conservative and right. In January 96 when he forecasted 1-2 feet before a flake had fallen I knew we were going to get nailed.

Sent from my motorola edge plus using Tapatalk


 

I know those Washington Star maps well. Used to deliver the Star a longggg time ago.

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high risk

high risk

Posted
Posted
51 minutes ago, NorthArlington101 said:


Could be one of those events where trees, colder surfaces are slick even in places that aren’t below freezing given its fairly frigid tonight and tomorrow.

     Spot on.      It's pretty clearly going to be well down into the 20s Saturday night before the temperature rises later at late.    All road surfaces will be super cold, so just getting to 32 or 33 Sunday morning won't end the icing threat.     It's also worth noting that the NAM Nest appears to be doing its usual thing of being slow with precip arrival, and the earlier start shown by some of the other guidance certainly suggests a fairly disruptive (and likely a high-impact) icing event.     The only thing keeping it from being an extreme high-impact event will be that it's on a Sunday morning.

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gymengineer

gymengineer

Posted
Posted
2 hours ago, Cobalt said:

Some rudimentary research, but here's what I could figure out.

1978-01-29 Follows a sizeable MA/NE storm on the 20th and predates the New England blizzard during Feb 5-7th (which we got scraps from).

1961-01-25 Follows a decent storm from the 18th-21st and predates a sizeable one from Feb 2nd-5th. DCA had a high of 18 and a low of 8 on the 25th, so a pretty frigid timeframe.

2007-01-28 Couldn't find much until well after 

Nice research! Just a couple of notes on these quoted dates:

The blizzard of 2/78 was a also a significant snowstorm from the northeast DC suburbs and northeastward, including Baltimore and especially northeastern MD. Immediate DC and west of the city did miss out.
 

1/26/61 was the only significant snow you missed on your entire list. 5.9” storm for DC. 
 

The end of January 2007 was notable not for a specific storm but for marking the pattern change that brought a wintry and very cold February. 

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WinterWxLuvr

WinterWxLuvr

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Posted
37 minutes ago, high risk said:

     Spot on.      It's pretty clearly going to be well down into the 20s Saturday night before the temperature rises later at late.    All road surfaces will be super cold, so just getting to 32 or 33 Sunday morning won't end the icing threat.     It's also worth noting that the NAM Nest appears to be doing its usual thing of being slow with precip arrival, and the earlier start shown by some of the other guidance certainly suggests a fairly disruptive (and likely a high-impact) icing event.     The only thing keeping it from being an extreme high-impact event will be that it's on a Sunday morning.

I agree with both of you. Sunday morning may be nasty

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nw baltimore wx

nw baltimore wx

Posted
Posted
2 hours ago, AU74 said:

I always felt that Ryan would cover all bases more than being conservative.

The original great DC weatherman was Louis Allen, imo.

Louis Allen? Damn. You's old. And then it was Gordon Barnes and Bill Kamal. 

It’s been alluded to already, but as much as I presently enjoy tracking and guessing the outcomes of snow, I miss the days of kneeling over the newspaper and seeing yesterday’s weather and trying to figure out tomorrow’s from a black and white map with data that’s at least 18 hours old. Even back than I obsessed, but I didn’t do it every six hours.

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Jebman

Jebman

Posted
Posted
3 hours ago, nw baltimore wx said:

Louis Allen? Damn. You's old. And then it was Gordon Barnes and Bill Kamal. 

It’s been alluded to already, but as much as I presently enjoy tracking and guessing the outcomes of snow, I miss the days of kneeling over the newspaper and seeing yesterday’s weather and trying to figure out tomorrow’s from a black and white map with data that’s at least 18 hours old. Even back than I obsessed, but I didn’t do it every six hours.

I remember Gordon Barnes. Wow I am VERY old lol

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Jebman

Jebman

Posted
Posted
8 hours ago, psuhoffman said:

Man there’s some crazy sh*t showing up on the long range guidance. Anyone notice the 18z Gfs nearly pulled off the same thing the ggem was doing at 12z but missed the phase by like 12 hours. Still managed a pretty good storm anyways but that was so close to a monster. I’ll say this…it’s rare we get the arctic jet amplified so far south as being indicated. It does open the door to some fun possibilities. 

It will happen, it will demolish the entire Mid Atlantic with Vodka Cold and seriously heavy snow - and it shall be dubbed The PSU Hoffman Blizzard of 2022.

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psuhoffman

psuhoffman

Posted
Posted
7 hours ago, WinterWxLuvr said:

Some may think I’m nuts, but if it snows 12” between now and Feb 11 I will call that an utter failure.

Those long range ensemble means are extremely smoothed and the members themselves are low resolution.  Plus it’s 10-1. So you’re not seeing the typical meso scale factors that cause places in the NW zones to get more snow.  
 

second those means are skewed towards climo and for most that is above climo for that period and the places that aren’t it’s because of factor 1 above.  

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psuhoffman

psuhoffman

Posted
Posted

Model performance analysis of 1/7 event 

I’m putting this here since I feel it’s relevant to factor in future analysis but mods can move it if they feel it belongs somewhere else. 
 

From super long range most guidance was amplifying the trough around a single SW and cutting a storm well NW of us. What eventually happened was the trough split with two SWs amplifying with just enough spacing to work out. The first pulled the boundary south and the second took advantage of that for us. But those are details I don’t expect guidance to get from day 8+. All guidance had the very general longwave pattern pretty well depicted imo. 
 

Once inside day 8 the euro was the first to pick up on the details and show the eventual outcome. But the Gfs and ggem were only about 24 hours behind and by day 5 all 3 had the synoptic setup mostly correct.  
 

The debate from day 5 in was about meso banding and transfer issues. Not things the globals can possibly nail at range. 
 

We knew there would be one max running to our NW and one max further east once the coastal developed. The globals picked that out pretty well fairly early. I remember discussing that possibility based on this type of setup on a zoom chat when it was still 5 days out then the next run both the euro and Gfs picked up on it.  That’s pretty good Imo. 

Around 2-3 days out most guidance was too far SW with the costal transfer and associated development of deformation axis.  Most guidance was showing that starting in the VA northern neck through the Delmarva  in reality that formed in Delaware and got going in NJ.  That’s a typical error and I never want to be on the SW edge of a developing miller b coastal.  That’s a recipe for a bust 90% of the time.  
 

Within 24 hours the euro, NAM3k and rgem did the best with banding and qpf.  Have to factor in ratios.  In this type setup even the kuchera can be low.  

Gfs was way too wet and developed the deform over DC instead of NJ.  Hrrr was too dry.  I’ve noticed it does ok with banding but often is too dry outside it.  Maybe it overdoes subsidence.  The href did very well but once inside 12 hours it’s hard to use since it’s only run every 12 hours and has a lag.  I really hope they continue to improve on the idea of a short range high resolution ensemble with the new fv3 system.  It’s a great idea that just hasn’t been perfected yet.

Last thought on the high resolution models.  They can be maddening because they’re susceptible to errors due to their high resolution.  But they can also see details the globals can’t.  The NAM often picks up on mid level warm layers first.  Imo when a high resolution model is in line synoptically with the consensus among the globals it’s a good idea to pay attention to their details.  Also does what they’re showing make sense.  If they have a mid level warm later, what’s the track of the mid and upper level low?  Is there a screaming southerly flow at h7?  Things like that.  Are those details on the globals just being underestimated due to lower resolution?  Apply some analysis to determine if what the high res guidance is saying is correct because it can see details better or an error due to going off on a tangent due to higher res.  
 

Overall I think the guidance did very well.  Resolving a miller b in a fast slow is extremely difficult and they got the synoptic idea correct from pretty far out.  

 

 

 

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Bob Chill

Bob Chill

Posted
Posted
4 minutes ago, Ji said:

Dark days ahead. Trough is way too far east. Too many competing shortwaves. Too much dominant northern stream. Phasing not in sync. Result: depressing model runs and waste of cold

Yep long range is depressing. Good thing our events have been popping in the mid/short range. Hidden from plain sight and makes Ji go something something 

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