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may 10-16 convection


forkyfork

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The severe threat tomorrow looks legit. When was the last time we had a decent EML combined with 50KT midlevel flow during the warm season? We are finally starting to see the steep midlevel lapse rates outside the cold season. The 12z Euro pounds the  NW burbs down to NYC.

 

NAMNE_con_lapse57_033.png.63b4ee3b165ff3b449ab131f4d90e28b.png

 

 

 

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1 hour ago, bluewave said:

The severe threat tomorrow looks legit. When was the last time we had a decent EML combined with 50KT midlevel flow during the warm season? We are finally starting to see the steep midlevel lapse rates outside the cold season. The 12z Euro pounds the  NW burbs down to NYC.

 

NAMNE_con_lapse57_033.png.63b4ee3b165ff3b449ab131f4d90e28b.png

 

 

 

it looks similar to may 18 2000

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How does the 56 degree SST play in all this.    Even 75 degree water in mid summer seems to weaken storms as they approach NYC.

The Skew-T is useful, but has been known to fail completely.  An example would be Chicago---July 13 or so, 1995.    The chart came out of the printer spinning----but nothing happened.   Vaguely remember Lake Michigan got into the mix somehow.

Anyone remember this and know what happened?    The heat reached us July 15 @102, but Chicago was 106, I think.

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KDIX

 
The bulk of the convective development in the afternoon just to
our northwest and west is forecast to occur with a secondary
short wave also tied to near a surface cold front. The arrival
of this feature during peak heating combined with ample boundary
layer moisture and stronger flow aloft will result in the
potential for strong to severe thunderstorms. It appears the
timing of the convection is after 18Z/2PM on Tuesday starting
across our western zones. While there are some differences on
the evolution of the convection, the wind profiles and
instability parameters should favor line segments. The more
unidirectional flow above the boundary layer should favor
embedded bowing segments. A plume of steeper mid level lapse
rates along with ample instability above the freezing level
should tend to favor some hail in the stronger updrafts. The
development of cold pools however and potential outflows to
enhance/focus eastward propagation will tend to locally enhance
the wind threat. The SPC has much of our area in a slight risk
for severe thunderstorms Tuesday afternoon with an enhanced area
just to our north.
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48 minutes ago, bluewave said:

It may be another case of the squall line remaining more intense along the North Shore than the South Shore.

I think the severe threat ends at the Hudson River. Areas further East should still get a good storm.

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The CAMs are pretty insistent on developing some QLCS spin-ups with the line in PA/NJ, which is consistent with the weak but slightly-backed low-level winds and the tendency for bowing segments driven by the excellent speed shear in the mid levels.  The HRRR wants to substantially weaken convection as it comes off the mountains in a Jersey, which is consistent with climo, but I wonder if the EML plume won’t overcome that today.  More CAPE then our usual.  Of course things will fizzle as soon as they hit the marine layer but that’s more NYC than NJ.

All the CAMs are supportive of a major supercell developing in the climatologically favored spot over the Mohawk valley and tracking over Albany to Springfield.  Would be very wary of tornados with that storm if it happens as modeled.  Where the winds back on the east side the Hudson River, Housatonic, and CT valleys, a storm can get a low-level meso going by sucking in some vorticity from the backed winds, and then the strong low level rotation can persist into the hills and the setup has produced  some of the big Northeast tornados (Great Barrington, Springfield, Worcester..)

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Wouldn’t be shocked to see a few spin ups over the interior today. Think the potential is there for big hail too, with wind as the greatest threat. Might even see upgrade to Moderate risk now that it’s clear that the morning convection won’t be a negative factor.

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24 minutes ago, NJwx85 said:

Wouldn’t be shocked to see a few spin ups over the interior today. Think the potential is there for big hail too, with wind as the greatest threat. Might even see upgrade to Moderate risk now that it’s clear that the morning convection won’t be a negative factor.

It's basically clear out to our west and no junk to burn off. That will stoke the fire.

 

image.gif

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29 minutes ago, NJwx85 said:

Wouldn’t be shocked to see a few spin ups over the interior today. Think the potential is there for big hail too, with wind as the greatest threat. Might even see upgrade to Moderate risk now that it’s clear that the morning convection won’t be a negative factor.

Yes I am quite shocked on how quickly things have cleared out this morning... still have some fog to burn off but it does really feel like those of the severe weather days... We'll see what happens.  Some of our biggest opportunities in the past came up empty but I believe that was mostly because of early morning activity and clouds lasting to long which this is not the case today!

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from the nws nyc ....Across the Enhanced Risk area, Bulk Richardson numbers are 15 to
25 indicating the potential for isolated supercells ahead of the
main line of storms. Given high Energy Helicity Indices and
Significant Tornado Parameter (both greater than 1) there is
the potential for isolated tornadoes, especially in any isolated
supercells that form ahead of the main squall line
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