Potential winter threats

[tombo82685]

i saw this in one thread on here. Harrisburg is the only city in pa that has not recieved an inch of snow yet. Just shows where the snow drought areas are.

[RobbTC]

Latest Mt Holly AFD out at 1540

PRETTY LARGE MODEL DIFFERENCES THEN AS TO WHAT OCCURS ON THURSDAY

NIGHT OR FRIDAY WITH THE ECMWF OFFERING A VERY VIGOROUS AND SNOWY

SOLUTION WHILE THE OTHER MEDIUM RANGE MODELS MORE MUTED. IT FEELS

LIKE DEJA VU ALL OVER AGAIN ALTHOUGH THE PLAYERS ARE NOT EXACTLY THE

SAME AS LAST WEEKEND. THE 12Z ECMWF IN AN UNUSUAL MOVE FOR IT IS

TAKING THE SWRN CLOSED LOW EASTWARD MUCH FASTER THAN ANY OF THE

OTHER MEDIUM RANGE MODELS THEN PROCEEDS TO FLIP THAT ENERGY (GOING

NE) WHILE THE CLOSED LOW IT HAS FCST OVER BRITISH COLUMBIA (WHICH IS

STARTING JUST SOUTHEAST OF SIBERIA TODAY) DIVES SEWD AND INITIATES

THE RAPID CYCLOGENESIS OFF THE CAROLINA COAST THURSDAY AFTERNOON. IN

KEEPING THE ENERGY IN THE SOUTHWEST, THE OTHER MEDIUM RANGE MODELS

ARE EMPHASIZING A WEAKER NORTHERN STREAM CLIPPER LIKE SOLUTION WHICH

ALL OF THE CURRENT GEFS MEMBERS ARE FORECASTING. WANT TO SEE MORE

RUN TO RUN CONTINUITY BEFORE OUR FORECASTS BECOME MORE ROBUST, BUT

FOR NOW HAVE STARTED DAY 7 WITH THE CHANCE FOR SNOW.

OVERALL IT REMAINS AN ATYPICAL OR THROW BACK NINA WINTERS FROM THE

EARLY 20TH CENTURY ACROSS OUR CWA. MR DON SUTHERLAND'S RESEARCH

INDICATES THAT THROUGH TODAY THE ARCTIC OSCILLATION (THE NORTH

ATLANTIC OSCILLATION IS PRETTY CLOSELY TIED TO IT) WILL SET A

BLOCKING (NEGATIVE) DECEMBER RECORD FOR ANY NINA WINTER SINCE 1950.

WITH BLOCKING WEATHER PATTERNS TOWARD THE POLE, THE COLD AIR IS

FORCED SOUTHWARD. THIS HAS PRETTY MUCH MADE THE TYPICAL LA NINA

CLIMATOLOGY OF RECENT NINA WINTERS DEAD IN THE WATER. THIS DECEMBER

FOR PHILADELPHIA WILL BE THE COLDEST DECEMBER SINCE 2000 AND THE

COLDEST MODERATE OR STRONG LA NINA SINCE 1955.

[jm1220]

I luv when you say old days. I guess being screwed on every storm event since 2003, it would seem old. ABE is joining you guys this year as being screwed in the snowfall record books, I guess the snowiest place in PA is no longer near Erie but in Philly. I swear this is not a La Nina year but an El Nino year and a La Nada year for us north of the PA turnpike

The snowiest place in the state will likely always be Laurel Mountain. They must average what, 200" of snow per year?!?! Johnstown is also a major lake/upslope snow area.

I'm not sure what the climate was back in the early 1900s, but surely some aspect of the Northeast climo seems to be changing in that central PA is becoming even more of a snow desert than before. You could chalk up to maybe a few winters in a row as coincedence, but this many suggests something more potentially.

[Manny]

Pretty interesting to have a similar set-up to Sunday's storm, with both offering solutions that can impact us with decent snows, just shows what a Strong La NIna with historic blocking can do for us.

[Feb]

I'll take a Miller B over a long tracked Miller A that would drop 2 feet on Philly and NYC anyday

Posts like these are why this guy deserves Weenie of the Year votes.

[eduggs]

The 18z NAM is leaving the SW cutoff mostly in place but strongly digging the northern stream energy through the Dakotas and south of there by 84hr. The s/w ridge in the ohio valley is strengthening and heights are building along the coast. This is the same basic idea as the 12z GFS, but with the "clipper" s/w and associated vorticity further south and the developing trof sharper and deeper. Extrapolated this could lead to some kind of coastal re-development and moderate event - more toward the middle of the week than the end.

I think we could get a storm next week with or without the SW cutoff sliding east. But something closer to the ECMWF idea increases the potential magnitude of impact.

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/nam/18/images/nam_500_084l.gif

[tombo82685]

The 18z NAM is leaving the SW cutoff mostly in place but strongly digging the northern stream energy through the Dakotas and south of there by 84hr. The s/w ridge in the ohio valley is strengthening and heights are building along the coast. This is the same basic idea as the 12z GFS, but with the "clipper" s/w and associated vorticity further south and the developing trof sharper and deeper. Extrapolated this could lead to some kind of coastal re-development and moderate event - more toward the middle of the week than the end.

I think we could get a storm next week with or without the SW cutoff sliding east. But something closer to the ECMWF idea increases the potential magnitude of impact.

http://www.nco.ncep....am_500_084l.gif

yea several of the gfs ens members have been showing an increase threat for atleast some snows in the wed-fri period.

[Grothar]

i saw this in one thread on here. Harrisburg is the only city in pa that has not recieved an inch of snow yet. Just shows where the snow drought areas are.

And I am sure Reading/ABE is not far behind. My new motto- keep the snowhole open. We should sell our salt to philly for thousands a ton when they run out. Well one good thing, no munic tax hike this year. Our public works guys are getting the mowers and weedwackers tuned up and ready

[Rainshadow]

What was the last year we had a strong Nina and several coastal storms/above avg snowfall in the PHL area? 95-96?

For a moderate or strong la nina to get well above gotta go back to 1916-7 or 1909-10, 1955-6 which is paralleling with temps (but not snow to date), PHL had 23".

[Rainshadow]

Well damnit, here we go again.

I think Tony (rainshadow) can probably help out with this, but I heard a little nugget this week that said that PHL has received 20 12"-or-greater snowstorms in its recorded weather history. 7 of these storms have occurred since 2003, and 4 have occurred in the last 54 weeks. If true, that's amazing.

12 of the 20 have occurred since the winter of 1995-6, yes 7 of 20 since 2002-3.

[bluehens]

Gotta throw out the 12z op Euro run. Its ensembles in no way support it and show a robust clipper bombing Miller B which I believe is what at least some other models show. South and West of NYC FTL again.

[RowanBrandon]

Yeah let's throw it out just like the HPC told us to throw out the 12z GFS on Christmas Eve.

[eduggs]

yea several of the gfs ens members have been showing an increase threat for atleast some snows in the wed-fri period.

I hadn't checked the GEFS since yesterday but after you mentioned it I see what you mean about this period. But none of them appears to dig the s/w far enough south to bring a good threat. Nor do any of them eject the SW cutoff like the ECMWF. The result is that the persistent central or eastern US trof remains relatively low amplitude.

I don't really like the look of the GFS or GEFS as they are now. But the ECMWF and the NAM (quick glance at the 12z Canadian looks a bit like the NAM) offers two different ways that this mid or late week threat could gain legitimacy.

[CooL]

Gotta throw out the 12z op Euro run. Its ensembles in no way support it and show a robust clipper bombing Miller B which I believe is what at least some other models show. South and West of NYC FTL again.

from what i understand the euro ens have a large spread, however, the GFS ens hint at a bombing miller b also...We have a looong way to go before we know what we are in for

[atownwxwatcher]

Gotta throw out the 12z op Euro run. Its ensembles in no way support it and show a robust clipper bombing Miller B which I believe is what at least some other models show. South and West of NYC FTL again.

I would not go as far as saying it does not support the operational solution but i also would not go as far as saying it supports it 100%...

At least from these images of the means it looks like there is a low pressure around Hatteras that would move NNE from there...

I would say at the very least it gives some support to the Operational run...where the operational run becomes a real outlier is actually out in its long range with the cutter...

[A-L-E-X]

I would have to think eventually that overrunning and cutting storms will return this winter, they just have to in strong Ninas like this. When that happens you guys are at least in the game for front end snows and ice. Maybe some clippers can also be beneficial, since they were usually the only kind of storm to regularly overperform in central PA when I was there.

Yea, but as the nina weakens, we end up with something like March 1956

Its not a strong nina anyway-- more like moderate.

[Feb]

I would not go as far as saying it does not support the operational solution but i also would not go as far as saying it supports it 100%...

At least from these images of the means it looks like there is a low pressure around Hatteras that would move NNE from there...

I would say at the very least it gives some support to the Operational run...where the operational run becomes a real outlier is actually out in its long range with the cutter...

Agreed. If you actually look at the frame before the one you posted, it has a weak low in Georgia that appears on the NC coast then off NE. DT posted on facebook that the euro had some, but not a lot of support from its ensembles.

[eduggs]

I would not go as far as saying it does not support the operational solution but i also would not go as far as saying it supports it 100%...

I would say at the very least it gives some support to the Operational run...where the operational run becomes a real outlier is actually out in its long range with the cutter...

Yup, that's decent support for a Day 6&7 chart. Obviously there's some spread so the s/w doesn't look so sharp on the mean chart. Looking back at days 3-5 it looks like some of the individual members leave the cutoff in the SW like most of the other guidance. But several of them must resemble the OP run to get the mean chart to look like it does.

[SteveB]

Wow, thanks Rainshadow! Those are some jaw-dropping comparisons. Here's to a healthy, happy, and safe new year to all and to more snow and cold so we can live thru an historic winter!

[eduggs]

Nothing great on the 18z GFS through day 6. There's room for improvement days 4-5 - I believe the s/w that breaks off from the PV to form a clipper and possible weak miller B type storm could dig further south and ignite something more significant.

At day 6 another lobe of the PV is poised to dive south. There's a tremendous amount of vorticity associated with it and the west to east elongation of the height field allows for the possibility of a much stronger miller B in later frames.

[eduggs]

Looks like the 18z shows a potent clipper to redeveloper. I like how there's little model consensus in the med/long range except on the basic idea of persistent storm threats and cooler than average temperatures.

[CooL]

The 18z gfs isnt going to clear up anything

the only thing you can take from this is its going to be cold with multiple storm threats (3 total on this run that bring us snow)

[Snowshack]

Gotta throw out the 12z op Euro run. Its ensembles in no way support it and show a robust clipper bombing Miller B which I believe is what at least some other models show. South and West of NYC FTL again.

You can't really throw out anything at 120+ hours, especially with how poorly the last two east coast lows were depicted this far out.

[daxx]

I know it is way out on gfs, but look at the lack of total qpf in the areas that just missed the last storm.

[Voyager]

http://www.erh.noaa....x.php?tab=norms

Obviously a rough, general map that doesn't account for every hill...but the basic idea is there...

That map is all wrong....eastern pa needs to be flipped north to south.

[snowlurker]

Just wanted to wish everyone who made tracking this year so fun - Tombo, Metfan Rainshadow, Wes, Don, ALL the mods and a bunch of others - a very Happy New Year!

[Grothar]

Sure looks like a snow hole to me- just date stamp last week and email it to HPC- they will never know

I know it is way out on gfs, but look at the lack of total qpf in the areas that just missed the last storm.

[atownwxwatcher]

I know it is way out on gfs, but look at the lack of total qpf in the areas that just missed the last storm.

Except that map can not even be accurate because of the following 60 hr total maps

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_p60_312m.gif

http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/namer/gfs/18/images/gfs_p60_384m.gif

[kpantz]

<br />Except that map can not even be accurate because of the following 60 hr total maps;

<br />This particular 384 totals map is contoured at 1" intervals. It's accurate.

[daxx]

Except that map can not even be accurate because of the following 60 hr total maps

I was only posting this map for laughs. We all know this will change, at least I hope.