Snow This Thursday/Friday

[Stormsfury]

but if its near newfoundland, any system across the east would weaken once it gets close to the broad confluent flow , anyway. so it has to be further north or out of the picture right?

Anything too far north gets sheared right out .. exactly .. however, with an active subtropical feed, the setup would be PRIME for a significant CAD event and overrunning moisture ... and you do NOT need a rapidly deepening cyclone to have profilic snowfall amounts ...

Also, the South/Southeast COULD have maybe one more last hurrah at the chance of a winter storm before the winter is out ...

IMHO, the setup does look conducive down the road for a MECS/SECS in early March ... but at the same time, would LIKELY initiate a pattern change afterwards ....

SF

[Stormsfury]

And with an active subtropical branch, there's a POSSIBILITY of actually getting a good GOM storm to crop up ...

[Kelly]

presidents day was an overrunning event, and gave the northeast very heavy snows. but probably a Miller A would be a much better scenario. that way the low is already fairly deep by the time it reaches the north carolina coast, instead of just developing in the inverted trough in a miller type B scenario.

[Stormsfury]

PD II was a very meager 1006mb low but coupled with a 1046mb HIGH in Eastern Canada which remained locked in and a solid feed of overrunning moisture made this storm so memorable, but the original PD Blizzard 1979 was quite a storm ... I don't have the specifics on it, but have 4 satellite images of the PD 1979 Blizzard ... and this one was just as memorable including in CHS with a severe icestorm (I was not even 7 years old, and still remember that icestorm vividly)...

SF

[Kelly]

didn't the low actually develop an eye like structure, the first presidents day storm in 1979 that is.

[Stormsfury]

didn't the low actually develop an eye like structure, the first presidents day storm in 1979 that is.

Yes ... this is the 3rd of 4 satellite pictures from the 1979 President's Day Storm ...

http://www.stormsfury1.com/Weather/WinterWeather.html

[Kelly]

wow, it has pretty nice looking inflow, and plenty of convection wrapping around the back side. almost looks like a hurricane. its the sharp thermal contrast that cuases that to happen right. a subtropical system to develop an eye?

[Stormsfury]

wow, it has pretty nice looking inflow, and plenty of convection wrapping around the back side. almost looks like a hurricane. its the sharp thermal contrast that cuases that to happen right. a subtropical system to develop an eye?

I believe what happened on the 1979 PDS was the storm became so wrapped-up that dry air got entrained all the way around ... but yes, there was a sharp thermal gradient ... I need to pull up some reanalysis maps for more details ...

Whoa, reanalysis maps absolutely shocked me on this one ...

February 18th, 1979 - 500mb level

February 19th, 1979 - 500mb level

February 20th, 1979 - 500mb level

[Stormsfury]

February 20th, 1979 - 850mb Temperatures

[R0bb0871]

I love those images! Make it happen again!

[Kelly]

it doesn't even look like the low closed off and the trough didn't have much amplitude either.

[Stormsfury]

it doesn't even look like the low closed off and the trough didn't have much amplitude either.

It totally shocked me also .. but notice the positioning of the PV, and the amount of cold 850mb temperatures ... (too bad the SFC temperatures aren't available on the Plymouth Reanalysis Maps) ...

February 18th, 1979 00z 850mb temperatures

February 19th, 1979 00z 850mb temperatures

Interesting ... the thickness schemes, with an obvious cold air damming scenario ... the 1000mb-500mb thickness schemes (5400 line) across NC....however, the 1000mb-850mb thickness schemes (1320 line) tell a much different story ...

02/18/1979 1000-500mb thickness scheme

02/18/1979 1000-850mb thickness scheme

02/19/1979 1000mb-500mb thickness scheme

02/19/1979 1000mb-850mb thickness scheme

SF

[Stormsfury]

Absolute vorticity at the 850mb level ... classic Miller B ...

February 18th, 1979

February 19th, 1979

February 20th, 1979

[FLguy]

the problem is 1000-850mb partial thicknesses account for temps below the 850mb level.

so if you were looking for a classic CAD signature using thickness methods you would like to see the 1000-850mb partial thickness contour south of the 850-500mb partial thickness contour. this is significant of low level cold air.

but even still partial thicknesses dont tell the full story. you could have a below freezing layer close to the surface and precip would freeze on contact even with thicknesses which are too warm to support ZRA. thats where soundings come in.

you dont always need a closed low, but in order for a decent deformation zone to set up and prolonged heavy snow to occur, you do want to see the mid levels close and the tilt of the trough become negative. which of course increases PVA and allows for stronger UVM to develop. eventhough the low never closed off, the tilt of the trough was meridional to start (as the s/w was digging and the trough undergoing amplification on the 18th) then began to tilt strongly negative as the s/w lifted out on the 19th and 20th.

[verycoolnin]

So... what do you think the setup will be on Thursday (anyone)?

[Stormsfury]

the problem is 1000-850mb partial thicknesses account for temps below the 850mb level.

so if you were looking for a classic CAD signature using thickness methods you would like to see the 1000-850mb partial thickness contour south of the 850-500mb partial thickness contour. this is significant of low level cold air.

but even still partial thicknesses dont tell the full story. you could have a below freezing layer close to the surface and precip would freeze on contact even with thicknesses which are too warm to support ZRA. thats where soundings come in.

you dont always need a closed low, but in order for a decent deformation zone to set up and prolonged heavy snow to occur, you do want to see the mid levels close and the tilt of the trough become negative. which of course increases PVA and allows for stronger UVM to develop. eventhough the low never closed off, the tilt of the trough was meridional to start (as the s/w was digging and the trough undergoing amplification on the 18th) then began to tilt strongly negative as the s/w lifted out on the 19th and 20th.

Which is why I'm bummed out that the Plymouth Site doesn't have SFC maps on the reanalysis ...

SF

[FLguy]

So... what do you think the setup will be on Thursday (anyone)?

sure its a good snow for the RAH-ORF corridor. per the ETA, if the GFS is correct than its little more than a waste of another s/w.

[FLguy]

the problem is 1000-850mb partial thicknesses account for temps below the 850mb level.

so if you were looking for a classic CAD signature using thickness methods you would like to see the 1000-850mb partial thickness contour south of the 850-500mb partial thickness contour. this is significant of low level cold air.

but even still partial thicknesses dont tell the full story. you could have a below freezing layer close to the surface and precip would freeze on contact even with thicknesses which are too warm to support ZRA. thats where soundings come in.

you dont always need a closed low, but in order for a decent deformation zone to set up and prolonged heavy snow to occur, you do want to see the mid levels close and the tilt of the trough become negative. which of course increases PVA and allows for stronger UVM to develop. eventhough the low never closed off, the tilt of the trough was meridional to start (as the s/w was digging and the trough undergoing amplification on the 18th) then began to tilt strongly negative as the s/w lifted out on the 19th and 20th.

Which is why I'm bummed out that the Plymouth Site doesn't have SFC maps on the reanalysis ...

SF

NCEP does or more specifically the CDC but im not sure of the exact URL

[Stormsfury]

Yeah I know, but I don't know the exact URL either ... otherwise, I'd have it linked on my website ...

[Anonymous]

Let it Become a 50/50 low! ( lol I sound like Jeb)

i dont know if thats such a good thing, chris.

Yes, He Is crazy, with snow, and cold......... But I for, one, Would love to see another March 1993 Blizzard.... or PD2...

WE have not had much snow here this winter. The NE got it in December. NJ and PA got it in January, and so did NC.

And yeah, I am Crazy about Snow and Cold. I definitely would not mind a Gulf Stream shutdown one little bit and I will not back off it no matter how reprehensible that is to everyone. Besides I do not control the weather. I still love snow and 50 below zero cold more than anything else in Life.

I can't wait til peeps start crying about how long Spring will take to get into the NE. Boy am I gonna have fun with those folks. I worship snow, I worship cold, and I openly make fun of people who choose to live up north where there is a lot of snow and they get stuck having to shovel all the snow, then cry about the fact that they have to shovel all the snow. Too bad. I aint gonna change. I worship snow and I worship cold and thats all there is to it. I am going to publish pages on my website that openly promote those ideas as well. I am sinking to new lows with this stuff. I can not believe how chilly we got in the MA this winter only to get hardly any snow.

Like I said I am Crazy about snow and cold and I am only going to get far, far worse. Snow comes First in my life, and always will.


ARCTIC SNOW BLITZ JEB!!!!PRAY THAT THE GULF STREAM SHUTS DOWN!!