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We appear to near the threshold into a new pattern - good opportunity to start a new forecast/banter

Typhoon Tip

By Typhoon Tip,
in New England

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Typhoon Tip

Typhoon Tip

Posted
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The other thread is now over-shadowed by the dark karma of banned souls ...  so let us begin anew as the summer sun seems to be on the verge of rising.  

 

Looking at NAO teleconnector, and although the summer correlation is considerable different the cold season, or even the transition seasons, still, I do not think it is a coincidence that the last time we experience midland heat, which is to say 88 to 94F over DPs around 60, was at the beginning of the month when the NAO spent a week positive.  The westerlies temporarily contracted polarward over eastern N/A, and heat ...more home grown, evolved.  

 

nao.sprd2.gif

 

Most operational guidance of the more dependable variety agree that as the weekend ages, heights will build and quite possibly exceed 588 DM to latitudes N of Boston-Buffalo.  This is less in the Euro, and perhaps extreme in the GFS.   Taking the compromised solution there may be the course of least regret, as there are reasons to argue against either.  I would like to see the Euro's NAO product, but just eye-balling the freebies ensemble mean, it appears the NAO domain is sufficiently positive in the deep layer heights for the operational run to ease off its tendency to lower heights up in the NE CONUS.   Here is just the D7 that the ECMWF offers on it's free site... What should leap out is that the mean has a much more smoothed over +NAO with lower heights well-behaved over D. Straight and Greenland, as opposed to the operational run, where we see a small wave-lengthed warfare of features up there.   

 

essential!Geopotential%20at%20500hPa!Nor

 

Big Heat, has no formal definition.  It's just an expression that's evolved over time -- I think Walter Drag may have introduced this while at NWS, Taunton back in the day.  Anyway, ...borrowed or not, there are markers/precursors to look for in determining the extremeness of summer-time positive departures.   Usually, preceding a big heat episode for the northern OV, southern Ontario, the MA and NE regions, there is a buildup of heated air over the Steppe climate regions of the deep SW CONUS.  This air is effectively capped from advecting out of that area due to governing synoptics -- usually by a period of +PNAP (Perennial north-American Pattern, not always the same set up as a +PNA) construct to the flow.  But then the pattern "sea-saws" ...sloshing back toward a -PNAP, with heights that tend to lower along the Pacific Coast. That releases the heat into (usually) a down-stream resulting ridging.  The flip from -NAO to +NAO has preceded just about every big heat scenario I have tracked.  Firey +19 to as high as +26C, 850mb temperature nodes situated amid a continental streamer of this heated air as it conveyors its way out of the deep SW.  Scott LOVES it when I refer to this as a Sonoran Heat Release.   

 

In this situation, we do see these precusors playing out more or less depending on guidance types.   Here is the D8, 00z operation Euro from PSU's e-wall, showing this nodal heat amid conveyor rather nicely, along with it's origin and the general behavior of getting pulled out of the deep SW by the deep layer circulation

 

f192.gif

 

The season as a whole, however, has had a repeating tendency to buckle and never quite shred the tendency for blocking packets N of the Can/U.S. border.  Until the tendency goes away, "big heat" may not verify too well.  I'm less than confident there.  I am more confident, however, that the run-up period, Sunday through Tuesday, should see a midland heatwave, perhaps similar to that of earlier this month, with somewhat higher DPs due to having crossed the evapo-transpiration threshold/soil moisture.   

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Damage In Tolland

Damage In Tolland

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Summer lovers are completely free and naked right now.

Late June Looks More Humid Across the Nation; Staying the Course July Through September Period

A trend toward the end of the month into the first week of July is higher humidity levels and fewer below-normal areas. There is a cool front later next week, but the intensity of coolness behind the front continues to trend weaker.

A rich, moist south to southeast flow will produce showers and thunderstorms from time to time this weekend through the middle of next week. Humidity levels will run high and drenching downpours leading to localized flooding will be the main threat. The area that could receive the heaviest rain during this period will be the Southeast, mid-Atlantic and Appalachians.

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Typhoon Tip

Typhoon Tip

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Maybe 3-4 days?

 

Yeah, I'm more confident in the nearing 90 Sunday to perhaps in 90s Tuesday and Wednesday than I am thereafter.   

 

Although, the D8 to 9 of the 12z Euro looks rather suspicious in the way it just arbitrarily tilts the flow NW through the GL....may be a premature end there.   I'm willing to entertain a shallow mid level wave denting the ridge with a cold front/thunder/MCS interval mid week, more so than a full-on trough digging in...  I've been hammering this Euro bias to cleave troughs out of the eastern N/A heights; it's fitting.   

 

So the lack of confidence after mid-week is based more upon seasonal trends.   

 

Will's right about the Euro ensembles.  The GFS members have had the suggestion too.  I actually wanted to start this discussion yesterday but was busy.

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CoastalWx

CoastalWx

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Yeah, I'm more confident in the nearing 90 Sunday to perhaps in 90s Tuesday and Wednesday than I am thereafter.   

 

Although, the D8 to 9 of the 12z Euro looks rather suspicious in the way it just arbitrarily tilts the flow NW through the GL....may be a premature end there.   I'm willing to entertain a shallow mid level wave denting the ridge with a cold front/thunder/MCS interval mid week, more so than a full-on trough digging in...  I've been hammering this Euro bias to cleave troughs out of the eastern N/A heights; it's fitting.   

 

So the lack of confidence after mid-week is based more upon seasonal trends.   

 

Will's right about the Euro ensembles.  The GFS members have had the suggestion too.  I actually wanted to start this discussion yesterday but was busy.

Definitely a hot signal as a piece of heat temporarily breaks off. The ULL well to our north backs off a bit while a trough helps eject heat from the high plains into the northeast. I do think the ridge will again retro back and we move into a pattern that maybe features fropas and periodic shwrs/tstms.

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Typhoon Tip

Typhoon Tip

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In the meantime, it's not hard to see why the GFS thought we'd be dealing with a coastal on those runs last week.  This looks pretty "leafy", and those of us N of the front have chilly (for June with NE breezes and mist.   Feels like a coastal is around.  

 

avn-l.jpg

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ORH_wxman

ORH_wxman

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In the meantime, it's not hard to see why the GFS thought we'd be dealing with a coastal on those runs last week.  This looks pretty "leafy", and those of us N of the front have chilly (for June with NE breezes and mist.   Feels like a coastal is around.

 

 

Yeah, it actually is a developing coastal storm along the sluggish frontal boundary...but barely misses SE tonight as it strengthens. ACK/Cape might get a little wind burst. Winds are already out of the northeast along the coast.

75c.gif

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weatherwiz

weatherwiz

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That 500mb pattern by the Euro thee would actually give some hope for a big severe weather setup.  We would be on the crest of the ridge, and this means we will be closer to the stronger westerlies and this is where your steepest lapse rates are likely to reside.  Could also be very active with s/w's along with MCS'

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Typhoon Tip

Typhoon Tip

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That 500mb pattern by the Euro thee would actually give some hope for a big severe weather setup.  We would be on the crest of the ridge, and this means we will be closer to the stronger westerlies and this is where your steepest lapse rates are likely to reside.  Could also be very active with s/w's along with MCS'

 

Yep, left the option on the table for Scott a while ago, in that a cfropa mid week was understandable and/or MCS activity.  The ridge node is initially west of us, and the flow is flat at 500mb escaping our region, and that has right turning barn burner written all over it.  Even without a cfropa, I would have to think there would be an MCS at one point or another in that flow. 

 

Than we'll see thereafter if that trough return has any merit.  Seasonal trends says yes, climatology and teleconnectors combined argue for less.  Couple of GFS ensemble members have the stellar dome toward the end of the month.   

 

Heat waves on this side of the Solstice out to about July 20th are particularly harsh for having such normal sun angles. 

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Typhoon Tip

Typhoon Tip

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Yeah, it actually is a developing coastal storm along the sluggish frontal boundary...but barely misses SE tonight as it strengthens. ACK/Cape might get a little wind burst. Winds are already out of the northeast along the coast.

75c.gif

 

Yep, seems the GFS had the right idea -- going back, I suspect convective feedback was falsity this time in allowing the low to deepen so demonstratively as it had it last week, more so than whether there would be a wave or not.  

 

Interesting...  I don't think the Euro had this wave developing ?   damn, wish I had taken note of that. 

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powderfreak

powderfreak

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Man it just finally got dark at 9pm and the temp is plummeting. 

 

At 915pm, down to 54F and some mesonet sites in the 1,200-1,500ft range are already tickling the upper 40s.

 

Bust out the sweatshirts for the campfire....bottle this up with 40s at night and 70s during the day into the weekend.  Then we see if the heat comes.  Maybe it'll hit 80F one of these days.

 

Tonight: Partly cloudy until midnight...then clearing. Lows in the mid 40s. Light and variable winds.

Wednesday: Mostly sunny. Highs around 70. North winds around 10 mph.

Wednesday Night: Clear. Lows in the mid 40s. Northwest winds around 10 mph until midnight...becoming light and variable.

Thursday: Sunny. Highs in the lower 70s. Light and variable winds.

Thursday Night: Mostly clear. Lows in the upper 40s. Light and variable winds.

Friday: Partly sunny. Highs in the lower 70s.

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