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July 2020 Discussion


Baroclinic Zone
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14 minutes ago, dendrite said:

Yeah that d9-10 euro knifing a plume of 24C in here is probably how a July 1911 played out. You had widespread 100-104° max temps with a few even higher including the NH record at Nashua of 106°. Get the right westerly flow with full sun and that 24C will do it...especially with more thermodynamic potential with relatively lower dews in the 60s. It’ll probably verify as a couple days of 20-21C though resulting in mid-upper 90s. 

For now...agreed... I'd even go 19 C as a base-line corrective assumption and think 94s.... 

Just seasonal trends, as we mused rightfully so yesterday - I'm a big fan of trend like that because they are really an echo of the background environmental mechanism - eventually, the teleconnections et al will dictate because energy and mass is conserving in every direction...blah blah blah. 

The GEFs agree with the EPS in the 500 mb hydrostatic layout within an acceptable margin of error, and both are nearing or at historic plausibility ... hmmm. Here's the thing:  It's the first time that has happened this year.... so, that could be a philosophical argument to offset said trends -we'll have to see. But both/blend offer a margin of error that would fit big hypsometric/scalar 850 mb numbers inside of those hydrostatic heights - ... Course, a cumulus butterfly notwithstanding...

The GEFs modulates by D10 into a look where probably it has a couple members tipping NW flow... going toward said consistent/seasonal agreement. That may introduce BD contensions and longevity ...probably start sending quasi-dry-line non-cold fronts that skrew us out of big numbers without actually being physical recognizable fronts... haha... you know how that works.  Meanwhile, the Euro is ratcheting up an even hotter D11 or 12 extrapolation with 25+C 850s west of ORD ready and completely able to dragon fart right on in here ... 

Yeah, that 1911 comparison...interesting.  It's too bad we haven't got a better re-analysis source work for that??  I mean the NCEP library is sketchy earlier than the 1950s...

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11 minutes ago, dendrite said:

Yeah that d9-10 euro knifing a plume of 24C in here is probably how a July 1911 played out. You had widespread 100-104° max temps with a few even higher including the NH record at Nashua of 106°. Get the right westerly flow with full sun and that 24C will do it...especially with more thermodynamic potential with relatively lower dews in the 60s. It’ll probably verify as a couple days of 20-21C though resulting in mid-upper 90s. 

100F is a challenge to reach here.

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11 minutes ago, dendrite said:

Yeah that d9-10 euro knifing a plume of 24C in here is probably how a July 1911 played out. You had widespread 100-104° max temps with a few even higher including the NH record at Nashua of 106°. Get the right westerly flow with full sun and that 24C will do it...especially with more thermodynamic potential with relatively lower dews in the 60s. It’ll probably verify as a couple days of 20-21C though resulting in mid-upper 90s. 

Until I see, the ensembles do it....I'm selling. The ensembles are impressive, but they still sow enough of a hint of it getting pinched and we end up with 20C for a day or two.

 

 

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1 hour ago, Typhoon Tip said:

Anatomy of a "Sonoran Heat Release"  ... Walter Drag coined this expression back ... Jesus, I wanna say around 2000 give or take, but I really like this turn of phrase because it does very nicely label the synoptic mechanism for how excessive/'BIG HEAT' gets acutely discernable and transmitted across the mid latitudes of North America.  

Below is a still frame animation of the 850 mb temperatures, which rather nicely elucidates how this type of heat expulsion from preprep synoptic west, is identifiably different than the background climatology of standard middle latitude summer warmth ... Typically there is a synoptic trapping and huge insolation charging of SW regional air mass within a lower theta-e environment; this concomitantly/physically expands heights and primes for hypsometric mixing should this air get ejected, where higher geometries or conserved... The soundings over those regions begin to represent that air... Elevated Mixed Layer is a marker, but the 800 mb temperatures in general might show surpluses.. then, a larger scale perturbation in the flow 'dislodges' segments of it and get pulled out.. Typically this happens because height falls near or descend through the Pacific Northwest, and down stream there is an establish mid level veering in the larger circulation eddy.  IF/when said air is then ejected, but then happens to time well with an anomalous mid level hydrostatic heights, the hypsometric heights are then getting a positive feedback on ability to expand diurnally. Tall boundary layers with very long surface potential temperature adiabats results... and this 'synergistic' sort of results in numbers that exceed the typology of summer heat for regions ..usually extending Iowa to New England/Mid Atlantics...

Below is showing how this phenomenon typically evolves in the 850 mb level...  From left to right .. top down, that's D6, 7, 8 and 9 of the 00z operational Euro ... Note, the last panel has a re-enforcing mass/plume ejection that is backloading the initial continental conveyor

(C/o "Tropical Tidbits" https://www.tropicaltidbits.com/analysis/models/):

sono.thumb.jpg.c3261bebaed208d44e2277578d9037bc.jpg

 

Here is the day-9 500 mb hydrostatic/heights layout for/during that ending frame above:

Eu.thumb.jpg.85210cb073aded32c8e1504c972b11eb.jpg

This is about as obscene and anomalous as I have ever seen one of these modeled ... in a vacuum, regardless of any man-handled and beef-witted assumptive mangled surface temperature products there may be in existence ...this would support 100 to 105 temperature readings in most urban and/or climate favorable locales or where not available to modulation from any local offset physical circumstances... extending across a mammoth geographical area of the CONUS... ORD/DET/BUF/NYC/BOS ... DCA-PWM ... the Tenn Valley to Missouri would all suffer excessive and historic/high risk heat criteria in the 2-meter.  And what would make this particularly bad is the synergistic feed-back from it being multi-day where the previous diurnal cycle services the next with an improved setting for heating across successive periods... 

I have lower confidence issues with this happening right now...  mainly because the seasonal trend to build larger 500 mb hydrostatic anomalies in the D6 to 10+ range has been dominating the guidance tenor as spring has aged into summer, and thus far, few or not have managed to transpire ...or not nearly with the same panache and resonance as these guidance depictions.  What has corrected routinely, is a NW flow adaptation as these latter ranges become more midrange proper...then verifying as NW/confluence circumstantially driving fropas and 'backdoor' type corrections in the lower troposphere east of OH/Kentucky ~ longitude.  

Having said that... I am not 0 confidence either :)  ha... seriously, the GEFs gave me pause...

Gfs1.jpg.6379bb102607e62d48a57c4e171c684c.jpg

That is an extraordinary appeal from that hugely ballasted mean - in that it has more perturbed members ( I believe ... check that -) but to have that sort of ginormous 594+ isohypses closed contour ...situated "reasonably" well/collocated over the same region as the EPS ...should at least send a flag.  I just don't know about the extremeness...and given to the fact that we are nearing the climatological apex of summer anyway, ... if we mute this by some reasonable conserved approach: (seasonal trend + individual model bias + typical D8 uncertainty)/3 ..it might = something less obscene and probably more like a standard heat wave.  

Meanwhile, we have advanced climatology/formally scienced papers being disseminated about these sort of events becoming more commonplace, both in N--S amplitude and W--E duration ( symbolically...).  I have personally noted that in recent summers, North America ( particularly eastern) has been spared these sort of "special" heat events that are synergistically over achieving ... The last time we had a run in with this higher tier exceptional heat expression, and had it actually succeed from extended modeling detection all the way into verification, was the big heat event in 2011 that ended with the historic Derecho that ripped from NP-MA in July that summer...  

 

 

 

 


Out of curiousity, how long does it take you to write a post?  :)

 

Thanks for the info.

 

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3 minutes ago, CoastalWx said:

Just based on the height look and the core of jet winds near the US/CA border..it might be good for a MCS or two given we straddle the edge of the hottest 850Ts.

Yeah I like being on the NE corner of that heat dome. Keep the 594-600dm garbage in the OH valley and Mid Atl. 

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47 minutes ago, dendrite said:

Yeah that d9-10 euro knifing a plume of 24C in here is probably how a July 1911 played out. You had widespread 100-104° max temps with a few even higher including the NH record at Nashua of 106°. Get the right westerly flow with full sun and that 24C will do it...especially with more thermodynamic potential with relatively lower dews in the 60s. It’ll probably verify as a couple days of 20-21C though resulting in mid-upper 90s. 

105 in Maine (Bridgton) and Vermont, for their hottest on record as well.  That 1911 furnace had the benefit of modest (low 60s?) dews in NNE, judging by minima in the 60s and diurnal ranges 35+, except at ASH which had minima to mid-70s.

Farmington co-op has touched triples just twice since 1911, reaching 100 in June 1944 and 101 on Hot Saturday in 1975.  Has not topped 95 since 1995. (And I hope it doesn't this year, either.)

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1 hour ago, dryslot said:

Socked in here with clouds so i don't know if we can destabilize enough for widespread severe up here, I always remain skeptical on these threats.

Weakening line of showers should go thru here in the next half hour, and trailing cloud debris won't help with destabilizing afterwards.

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Just now, tamarack said:

Weakening line of showers should go thru here in the next half hour, and trailing cloud debris won't help with destabilizing afterwards.

Couple very brief peeks of sun here so far today, I see that line drying up as it moves SE thru Central ME.

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