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Potent pattern for part TWO being an impact event NYC subforum Thanksgiving weekend: Fri-Sun 11/26-28.


wdrag
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7 minutes ago, wdrag said:

Good Wednesday morning everyone,

Models having trouble with this coming pair of events, but the trend to slowing and coming back for the GFS and GGEM may have started with these 00z-06z/17 cycles. Too early to wave the white flag and surrender to the too far east, benign scenario. 

You've seen the 06Z GFS OP with flurries to LI and measurable north of I80. It's just one member of many.  

I am favoring the 00z/17 GEFS/GFS solutions over what I think are wayward east solutions for the 00z/17 EC/EPS.

To describe the differences... the EC solution has a positive tilt to developments over the area 12z/23-Tuesday. See the 500MB flow pattern. It's an unlikely development, in light of the consistent signal of prior ensembles. 

Attached are the 00z/17 GFS OP 500MB, EC OP,  EPS 500MB (tilted more neutral than it's single member OP, GEFS 500 [ignore the color difference-differing normalizing scheme], and the midnight WPC outlook for more than 3" of snow, basically Tue/Wed which confines the small (10-29%) ensemble chance of decent snow north of I84. 

 

Beyond For-Sat after Thanksgiving continues on the table for measurable snow closer to I95. It's in the favorable -NAO expectation.

Thanks is extended to Pivotal Weather and US Weather and NOAA for these graphics. 

Screen Shot 2021-11-17 at 5.00.29 AM.png

Screen Shot 2021-11-17 at 4.59.19 AM.png

Screen Shot 2021-11-17 at 5.09.20 AM.png

Screen Shot 2021-11-17 at 5.10.11 AM.png

Screen Shot 2021-11-17 at 5.13.17 AM.png

This to me seems like the typical model uncertainty we see at this range with every potential large storm event. We should start to get a clearer picture of what will occur over the next 24-48 hours. 

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25 minutes ago, Rtd208 said:

This to me seems like the typical model uncertainty we see at this range with every potential large storm event. We should start to get a clearer picture of what will occur over the next 24-48 hours. 

Yep... the images posted show how touchy the pattern is to flow patterns, exampling the EC OP as relative outlier when compared to ensembles.

If the models do not trend west from here (06z/17) by this weekend, then it's a more or less typical Nov storm with backside flurries to the city, and scattered wind gusts 40-55KT on the backside, but not the bombogenesis HIGH impact portrayal for our area that was advertised a day or two ago. 

I still think upper lows are trouble and this needs to be monitored for an eventual slightly further southwest and stronger sub 980MB trend into southeast New England. Just my 2c, have no science to back up my concern...just my visual impressions and knowledge of previous guidance. 

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I agree Walt. But IMHO, this  typical model chaos for 5-10 day outlooks points out to a major pattern change in the workings which usually brings in an onslaught of Alberta Clippers/cold fronts to our area during the first week of December.  December 5-7 time frame is very typical for the first accumulating snow for the tri-state area. Anything accumulating before this time frame is a bonus. These  upper level lows are also notorious for  setting up overrunning precip events  a few days later after the frontal passage. 

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19 minutes ago, Albedoman said:

I agree Walt. But IMHO, this  typical model chaos for 5-10 day outlooks points out to a major pattern change in the workings which usually brings in an onslaught of Alberta Clippers/cold fronts to our area during the first week of December.  December 5-7 time frame is very typical for the first accumulating snow for the tri-state area. Anything accumulating before this time frame is a bonus. These  upper level lows are also notorious for  setting up overrunning precip events  a few days later after the frontal passage. 

Yes,  plenty to monitor.  

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The ICON, CMC, and the EURO all get the 2mT down to 30-32 near Tues AM----but the GFS fails and in late Nov/Dec heads for the 50's anyway.

The CMC has a bit of White Stuffing here to boot................

1637150400-EC4O40TDttY.png

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Can't comment too much on how things will transpire.  These are chaotic model runs.

I looked at the 12z/17 ensembles, and this 500MB trough maximizes all its weather over New England-our area and then weakens eastward.  It seems a little bit progressive...not closing off deep (slow) enough. Yet the progressive EC has -33C over us at 500MB around Tue night-Wed morning.  That warm water along our shores should be a player in the deepening process - lapse rates. Will check back Thursday morning.

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Nothing going on yet, that warrants lots of confident hazard occurrence attention. Nice looking potential at 500 MB but surface response is chaotic as someone previously pointed out. Not throwing in the towel yet as we are 5-7 days out for event one, and 9-11 days out on event two. 

As I sit here at 624A having reviewed my favorite 00z/06z Nov 18, 2021 ops/ensembles...I see slightest chance for iso SVR early Monday morning the 22nd, scattered back side wind gusts 40 knots or so Wednesday, especially NYC/NJ/PA.  Backside very minor snow looks to me like I84 elevation best and just a small chance for a few flurries NYC Wednesday.

The event for next Friday-Sunday, whenever it occurs is also chaotically modeled from cycle to cycle. It is I think beginning to edge out the first one on general qpf, but it too may be too warm except maybe for I-84 elevations.  I do think an event is coming then... and maybe if its too warm, we'll see some brief scattered backside wind of 40 knots.  

A nice looking potential pattern based on the developing Greenland Block,and it's enhancing digging-sharpening  500MB trough of early next week,  but what it yields, is uncertain. Still worthy of monitoring.  Will check back again this evening if consensus modeling is favoring something more than ordinary for late November.  Not changing title down (HIGH impact) because it's Thanksgiving travel-shopping week and modeling may yet coalesce to a stormier impact pattern around here. 

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Attempting to shift the conversation back from METS GM to what still needs to be monitored via the 06Z GEFS animation.  Note at 18z Tuesday, the most intense phase of this system is in progress with a -6SD=purple (for the season and our LA/LO) 500MB trough that is closing off further and further south.  This is the multi member display and averaged.  Lots can be gained from animating (checkmark) and or scrolling through the times.  Other features of note are a good positive tilt track for the next weekend system with vort probably across NJ,    AND      this 06z GEFS modeled continuing depressed (maybe too far south) storm track in early DEC with still above normal heights in northeast Canada. 

 

http://www.meteo.psu.edu/fxg1/ENSHGTAVGNH_6z/ensloopmref.html

 

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2 hours ago, wdrag said:

Attempting to shift the conversation back from METS GM to what still needs to be monitored via the 06Z GEFS animation.  Note at 18z Tuesday, the most intense phase of this system is in progress with a -6SD=purple (for the season and our LA/LO) 500MB trough that is closing off further and further south.  This is the multi member display and averaged.  Lots can be gained from animating (checkmark) and or scrolling through the times.  Other features of note are a good positive tilt track for the next weekend system with vort probably across NJ,    AND      this 06z GEFS modeled continuing depressed (maybe too far south) storm track in early DEC with still above normal heights in northeast Canada. 

 

http://www.meteo.psu.edu/fxg1/ENSHGTAVGNH_6z/ensloopmref.html

 

sounds like 1989

 

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Ordinary weather... despite the developing pattern aloft next week. I like the 00z/19  10 day ops, but it's 10 day, just like the 10 day outlooks waere for this coming Monday-Wednesday, which probably won't be much more than developing blustery chill and some flurries, maybe even a flurry down to NYC?  

If and when the shorter term offers a little more than a 40 kt gust here and there, or deposits snow/ice over the interior...I'll tend to refrain from commenting.  This coming Mon-Wed ahead ends up too late too far east, earliest hint of this was the GEFS a few days ago, in the initial topic discussion.

Til whenever,  have a good day(s) shopping-prepping for the Holidays. 

 

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On 11/19/2021 at 7:43 AM, gravitylover said:

I know it's outside the local zone but is the weather also going to be benign between here and the western end of the state? I have to drive out and back Mon/Tues.

Monday: bands of Lake Effect snow showers in the wake of the CFP, mostly Catskills Poconos northwestward on Monday.  Lingering flurries Tuesday morning. You should manage fine. Smart driving. 

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On 11/19/2021 at 6:07 AM, wdrag said:

Ordinary weather... despite the developing pattern aloft next week. I like the 00z/19  10 day ops, but it's 10 day, just like the 10 day outlooks waere for this coming Monday-Wednesday, which probably won't be much more than developing blustery chill and some flurries, maybe even a flurry down to NYC?  

If and when the shorter term offers a little more than a 40 kt gust here and there, or deposits snow/ice over the interior...I'll tend to refrain from commenting.  This coming Mon-Wed ahead ends up too late too far east, earliest hint of this was the GEFS a few days ago, in the initial topic discussion.

Til whenever,  have a good day(s) shopping-prepping for the Holidays. 

 

Good morning Walt. My 8th decade has left me with an ample supply of old sayings. One I value is ‘forewarned is forearmed’. You, as a compassionate professional do no more than that. And if, by a stroke of good atmospheric fortune, an extreme event is averted, your value is not diminished but increased. For me being ready is far better than being not. As always ….

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4 hours ago, rclab said:

Good morning Walt. My 8th decade has left me with an ample supply of old sayings. One I value is ‘forewarned is forearmed’. You, as a compassionate professional do no more than that. And if, by a stroke of good atmospheric fortune, an extreme event is averted, your value is not diminished but increased. For me being ready is far better than being not. As always ….

Well said. :clap:

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4 hours ago, rclab said:

Good morning Walt. My 8th decade has left me with an ample supply of old sayings. One I value is ‘forewarned is forearmed’. You, as a compassionate professional do no more than that. And if, by a stroke of good atmospheric fortune, an extreme event is averted, your value is not diminished but increased. For me being ready is far better than being not. As always ….

Thank you for your note...   I try not to gaffe too many, otherwise it's crying wolf.  We did know that it wasn't a lock. 

This first one is quite the weakened-positive tilt 500MB trough that both ensembles at 7 days and beyond had considerably wrong, GEFS more so than the more progressive EPS.  Disappointing yes, but the expected and still to develop near Greenland block I thought would be enough to justify the consideration.  Event #2 is still on the boards, even if miniscule. Could be a windy cold event with a few flurries or something a little more but overall... I think at least through Thanksgiving, most welcome the relatively quiet pattern here.  

No comment on event #2 til it's more certain to be nothing or something.

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  • wdrag changed the title to Potent pattern for part TWO being an impact event NYC subforum Thanksgiving weekend: Fri-Sun 11/26-28.

Thread now refocuses headline on part TWO 26-28, w possible extension to 29 in the future. Part ONE failed due to modeling leading up to the 15th issuance being too deep aloft, too quick. Ended up further east and we were dry with a chill gusty wind.  Tags: dropped heavy rain, and changed damaging wind to wind event.

Modeling beginning with the cycles of Tuesday the 23rd have increasingly hinted at a possible wind advisory event for part of the area later Friday into Saturday morning followed by some sort of snow or flurry event Sunday - possibly lingering into Monday. Questionable outcome but we do know the modeling is digging a 3rd strong short wave trough into the northeast USA late this coming weekend. Therefore, while the first on the 23rd didn't produce hazardous weather, the second may generate a bit of a wind event in the wake of the cold frontal passage late this Friday, and the 3rd may allow some sort of coastal low to develop Sunday, departing Monday the 29th. Uncertainty exists.

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Thanks for the posts...  I have yet to examine 12z/24 ensembles and probably won't be able to til after 8P... but,  probably good to discuss this coming pair of events (Fri, Sun-Mon).  Timing short wave passage Monday seems differ on the models.  Anyway, glad it's still viable.  I may be too enthusiastic but it's a bit of a start. BIG N Atlc BLOCK has helped set it up... 

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35 minutes ago, LoboLeader1 said:

 Climatology wise I would tend to hedge on a non-event here. Folks N & W will likely fare better with frozen precip.

 

 

 

 

I think mood flakes are becoming more possible Sunday with potential for something more. 

Really depends on how much the shortwave is able to dig. We do have cold air around which is positive.

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