Friday/Saturday ... significant Appalachian upslope event ..

[Stormsfury]

possible ...

18z ETA/GFS indicates strong upglide across the western banks of the Appalachians Fri thru early Sun which COULD possibly lead to a signficant upsloping event from the NC Mountains northward across the Appalachians ...

The 18z ETA is a bit drier than the 18z GFS, with the 18z GFS indicating POTENTIAL light snows even into the Carolinas w/a s/w trough rounding the base of the cutoff 500mb low over the MA/NE ... typically, downsloping effects prevent much in the way of anything moving from the NW down into the Carolinas appreciable distances away from the mountains ...

ETA 72-78 hours




GFS 72-78 hours




Discussion ...

southern stream energy loads up and pulls northeast out of the GOM while a strong disturbance in the northern stream catches up and phases with the southern system energy. Quite a trough gets carved out in its wake, with s/w disturbances rounding the base of the trough will serve to enhance lift and upglide across the Appalachians. with the upslope component, favored areas COULD receive their first significant snowfall of the season (significant meaning 6" or greater in the favored locations) ...

further downstream across N GA, and into the Carolinas away from the mountains, raw, cool conditions as cold air wraps around the 500mb low and enhanced by leftover moisture (shallow in nature), thickness schemes fall BLO 540dm across GA, and the Carolinas, and COULD spell some flurries. The GFS is too generous with the widespread amount of light QPF coverage.

MR prognostics (Days 8-10) according to the 12z ECMWF mid-month get EXTREMELY interesting with a decent s/w coming into the W US, with a strong E trough held fast by the ridge which HAD been hurting the snowhounds so often this season to date, and COULD be the makings of an overrunning event with CAD ...

SF

[Pileus]

I just hate watching those ragged east bound cumulus clouds just after
FROPA knowing that the mountains have ONCE AGAIN wrung all the
moisture from the atmosphere. Actually disheartening looking on the
horizon to the west seeing the darker cloud deck. I've got it bad.

[JenyEliza]

Here we go......our first winter roller-coaster.....

Let's hope it brings a little snow flurries to put some cheer in our Christmas shopping.

[wxguy25]

As far as the FRI-SAT event goes…The 18z GFS and 12z ECMWF support a SIGNIFICANT St. Lawrence valley snowstorm based on the track of the SLP and 500mb s/w. elsewhere I don’t see sufficient cold air for this to be a Midwest snowstorm and much of the Lakes region will see rain also. The EXCEPTION may be northern New England which could see some ZRA/IP/SN to begin.

I noticed a CLASSIC ZRA signal on the GFS sounding at KCAR valid at 18z SAT however it would appear that the best lift has pulled to the north of the region and eastern ME actually gets dry-slotted. IF the GFS is to be correct, there could be a burst of heavy snow across N NE/ME before a change to freezing Drizzle BUT the St. Lawrence valley should see the highest totals.

There may also be a MAJOR LES event in the favored regions from MI eastward to OH/W PA/W NY since the lakes are unfrozen and as warm as 10C/50F in some locations. This combined w/ strong NW flow and CAA behind the 850hPa low as it heads up into the St. Lawrence valley and pockets of -6 to -9 C 850mb temps overspread the region. Instability may be enhanced as a few weak shortwaves move over the region compounding the threat for heavy accumulations downwind of the lakes, and yes, some of the snow showers/squalls COULD make it east of the, mountains.

When it comes to the Second and VERY potent follow up s/w I don’t see it being able to dig. There is NO 50-50 low, no blocking (and the NAO for the most part is positive) and the PV is out of the picture—thusly there is nothing to drive it southward, so it slips across the lakes and into New England. Granted there could be SOME decent snows to the North of the track of the 500mb low, but no major east coast snowstorm will become of this for those reasons. Remember the three most critical factors influencing the development of a Blockbuster east coast snowstorm is the relationship between the 50-50 low, Blocking, and PV.

The 12z ECMWF D8-10 Was IMO very disappointing. The PV is located over NE Greenland which is indicative of a +NAO and assures us that there will be no MASSIVE arctic intrusion into the EUS through the 20th IF it were to verify. As some of you are well aware, the 0z OP-GGEM had quite a different idea. Notice however the changes over the PAC, there is a clearly defined Aleutian low which is developing the downstream PNA ridge and allowing the trough to come into the EUS. The ridge developing east of SCANDINAVIA and low attempting to cutoff near the Caspian Sea may eventually lead to a rex-blocking scenario over the region perpetuating the re-emergence of the Caspian connection.

Ill have an updated WXBLOG section tomorrow afternoon.

[stormman]

wxguy25, doesnt sound too promising for snow according to you forecast. Yesterday was sounding much better. I know yesterday I heard a poss big winter storm in the 16-18 timeframe. Are you saying that isnt an option anymore. And if not, when do you see any chance for snow for the big cities?

thanks

[breeze]

Local mets are touting snow flurries/showers for Friday
into Saturday. The ground is too warm for it to stick, but,
it sure would be nice to see, anyway.

[therock1811]

Take a look at this Breeze!



This is the 0z (or 7pm) ETA's precip type forecast! Indicates snow across TN/most of KY/OH/IN. And for me here in northern Kentucky? RAIN!

Either way everything seems to point to a significant upsloping event for sections of eastern KY and TN/W VA/WV/and on up the Apps. Even I think where the ETA shows rain on up through WV/PA/NY.

[stormraiser]

Woohooo..... shows snow for me

[yoda]

Woohooo..... shows snow for me

Of course its snow for you Anthony...

[Guest]

There will be NO snow in the I-95 corridor until at LEAST the 16th. Then things may get very interesting. We will have the cold, all we will need is the moisture. AS OF NOW, looks to be highs in the 30's AT MOST for DC Philly and NY, Im thinking highs will probably be in the lowers 30's in DC and Philly and maybe upper 20's in NY. This will be the first very cold air of the season coming up May even see lows in the lower teens in the Western burbs of DC and Philly.

In the upcoming winter storm possibility (17th-20th) current thinking of mine is..... coast will see a rain/mix, I-95 will see mostly snow, and West of the highway will see all snow. For fun, I'll go with 4-8 inches in the cities and the burbs (higher amounts in Western burbs). I do think we will see our 1st significant winter storm of the season around 10 days from now.

After this storm, looks like we still have the cold air and the possibility of ANOTHER winter storm in the East around Christmas, current thinking is lighter than the first (2-4?) May also have a few clippers in between and afterwards. After New Years looks like the pattern will moderate again and we will be back in the 40's and 50's.

[breeze]

Jeremy, I'll tell you like I told my Mama...LOL....
ground's TOO warm - won't stick! I think the
local mets are even kinda laughing about us getting
flurries, now...I think someone wanted to make
Christmas sound REAL white, here....