Threat Jan 25-28th time fram. Possible Miller A

[eduggs]

wow man! this is freakin awesome!! sign me up now for this

Hell yes. Me too! Long duration and cold. Can get a good night sleep without missing all the action. Still potentially prolific but doesn't depend on the perfect storm track.

[Edge Weather]

Yes, I guess we could call this one epic.

[Snowtrain]

la epic is the only enso state this winter is in

indeed!

[tornadojay]

I was comparing the surface maps to PDII.. with this particular run, the placement of the high is almost exactly the same... 850 temps were similar... The high pressure in PDII was a bit stronger... up to 1044 at one point before the storm arrived, but most of the time, it was in the 1032 - 1036 range.

[SnoSki14]

I guess its a rainstorm if the NOGAPS says so? The GAPS has been pretty west this year.

Yeah it would be but the NOGAPS this far out would be like the gfs beyond 300 hours.

[wkd]

Yes, I guess we could call this one epic.

By the way, you did an excellent job with the pbp. Seems Tombo prefers to stay in his own area. Let him.

Also, so much for the Euro bias to hang back energy. Maybe we should now say the GFS and GGEM have that bias.

[SnoSki14]

I was comparing the surface maps to PDII.. with this particular run, the placement of the high is almost exactly the same... 850 temps were similar... The high pressure in PDII was a bit stronger... up to 1044 at one point before the storm arrived, but most of the time, it was in the 1032 - 1036 range.

The high pressure was also centered further west than what the Euro shows which kept us very cold. Timing will be key though, there's not much room for error w/o blocking and a 50/50 low. Like someone stated before, PD II could have been a big rainstorm had it come a day later.

PD II was probably the only time such a weak low could produce such prolific snowfall amounts. Before it, I would also imagine that lows had to be very strong in order for us to get a big storm but that is clearly not the case.

[TheTrials]

By the way, you did an excellent job with the pbp. Seems Tombo prefers to stay in his own area. Let him.

Also, so much for the Euro bias to hang back energy. Maybe we should now say the GFS and GGEM have that bias.

UKIE GFS AND GGEM all went crazy with sending the short wave to mexico only to get stuck with the INS when it tried to come back into the gulf.

Euro doesnt dig it and then closes it off in response to PNA amplification and then the east based -NAO and send the closed H5 rolling across the county in a perfect spot for the North East.

[A-L-E-X]

The high pressure was also centered further west than what the Euro shows which kept us very cold. Timing will be key though, there's not much room for error w/o blocking and a 50/50 low. Like someone stated before, PD II could have been a big rainstorm had it come a day later.

PD II was probably the only time such a weak low could produce such prolific snowfall amounts. Before it, I would also imagine that lows had to be very strong in order for us to get a big storm but that is clearly not the case.

No-- we actually want a weak low for a widespread area of heavy snows and not just have banding with lots of haves and have nots. Feb 1983 was the same.

[Chris L]

The high pressure was also centered further west than what the Euro shows which kept us very cold. Timing will be key though, there's not much room for error w/o blocking and a 50/50 low. Like someone stated before, PD II could have been a big rainstorm had it come a day later.

PD II was probably the only time such a weak low could produce such prolific snowfall amounts. Before it, I would also imagine that lows had to be very strong in order for us to get a big storm but that is clearly not the case.

The Blizzard of 1983 was a very weak sfc low, only 1004 mb, which is weaker than PD of 2003.

[A-L-E-X]

Hell yes. Me too! Long duration and cold. Can get a good night sleep without missing all the action. Still potentially prolific but doesn't depend on the perfect storm track.

Yea, this would be like the perfect snowstorm-- lots of qpf, long duration, I get my daytime snow Let's hope it verifies.

[Harbourton]

By the way, you did an excellent job with the pbp. Seems Tombo prefers to stay in his own area. Let him.

Also, so much for the Euro bias to hang back energy. Maybe we should now say the GFS and GGEM have that bias.

I just think Tombo was in the moment as the Euro came in with this epic solution and stayed in that thread.

[A-L-E-X]

The Blizzard of 1983 was a very weak sfc low, only 1004 mb, which is weaker than PD of 2003.

The best kind of set up for a widespread 20" snowfall for our area is a weak sfc low moving slowly up the coast into a very cold dome of arctic air-- in short, get the Pacific moisture to hose into the cold air and you've got prolific snowfall totals over a wide area.

[jrodd321]

Can someone explain to me how the weak low but strong high creates high snow amounts? Just curious.

[TheTrials]

The high pressure was also centered further west than what the Euro shows which kept us very cold. Timing will be key though, there's not much room for error w/o blocking and a 50/50 low. Like someone stated before, PD II could have been a big rainstorm had it come a day later.

PD II was probably the only time such a weak low could produce such prolific snowfall amounts. Before it, I would also imagine that lows had to be very strong in order for us to get a big storm but that is clearly not the case.

There is a 50/50 low and there is an east based -NAO and because the surface low is weak the HP can hold on just long enough before the 50/50 moves out but the 50/50 moves up and not out to sea in response to the east based -NAO.

[atownwxwatcher]

Yeah it would be but the NOGAPS this far out would be like the gfs beyond 300 hours.

Not really true..the Nogaps was more west with every system this year then the rest of the guidance and what verified in the end was a more western track including this event coming later tonight into tomorrow.

You generally do not want to see a model such as the NOGAPS with a very progressive bias that far NW...the reality of the NOGAPS would have it to the SE by a wide margin with its bias. However...its not...its west...

[tornadojay]

Can someone explain to me how the weak low but strong high creates high snow amounts? Just curious.

they key in this type of situation is a strong baroclinic zone or coastal front right along the coast that is basically an enabler for upward forcing... that, along with a persistant flow from the east, overriding that, creates your constant heavy precipitation..

Why is a weak low key as well? With a strong low, you have the risk of introducing too much warm air into the equation, but a weak low pressure at the surface, 850 mb, and 700 mb is just enough to keep the forcing going without allowing the warmer air to advect too far westward. The result is that the temp charts at that level remain constant and you just keep the coastal front in the same position and just use it to your advantage for hours on end

[H2Otown_WX]

Can someone explain to me how the weak low but strong high creates high snow amounts? Just curious.

Good article about PDII explains how the weak surface low was able to produce heavy snow: http://www.cbs6albany.com/sections/weather/historical/paststorms/2003/Feb17-2003_PresidentsStorm.htm

[A-L-E-X]

Not really true..the Nogaps was more west with every system this year then the rest of the guidance and what verified in the end was a more western track including this event coming later tonight into tomorrow.

You generally do not want to see a model such as the NOGAPS with a very progressive bias that far NW...the reality of the NOGAPS would have it to the SE by a wide margin with its bias. However...its not...its west...

Yes, but we'd like the euro track more than the nogaps one.

[A-L-E-X]

they key in this type of situation is a strong baroclinic zone or coastal front right along the coast that is basically an enabler for upward forcing... that, along with a persistant flow from the east, overriding that, creates your constant heavy precipitation..

Why is a weak low key as well? With a strong low, you have the risk of introducing too much warm air into the equation, but a weak low pressure at the surface, 850 mb, and 700 mb is just enough to keep the forcing going without allowing the warmer air to advect too far westward. The result is that the temp charts at that level remain constant and you just keep the coastal front in the same position and just use it to your advantage for hours on end

The funny thing is, you'd expect this kind of set up in a moderate or strong el nino (both 1983 and 2003 fit that category), not a moderate or strong la nina lol. I guess the +PNA is giving us an el nino pattern.

[tornadojay]

I wish the Euro showed 250 mb jet, but PDII had us in the right entrance of a jet streak which was also very adventageous.

[tornadojay]

The funny thing is, you'd expect this kind of set up in a moderate or strong el nino (both 1983 and 2003 fit that category), not a moderate or strong la nina lol. I guess the +PNA is giving us an el nino pattern.

from straight out of the book.... all credits on this quote to K&U, btw..

"This storm developed during a winter during which a moderate El Nino was present and the NAO tended toward a negative value. That said, the storm actually developed in a period of winter where the El Nino was weakening and when the sign of the NAO was actually positive"

[Harbourton]

they key in this type of situation is a strong baroclinic zone or coastal front right along the coast that is basically an enabler for upward forcing... that, along with a persistant flow from the east, overriding that, creates your constant heavy precipitation..

Why is a weak low key as well? With a strong low, you have the risk of introducing too much warm air into the equation, but a weak low pressure at the surface, 850 mb, and 700 mb is just enough to keep the forcing going without allowing the warmer air to advect too far westward. The result is that the temp charts at that level remain constant and you just keep the coastal front in the same position and just use it to your advantage for hours on end

Nice explanation! These type of storms have that slow precip creep up the coast that can drive you nuts.

[Kaner587]

I'm just amazed at the constant parade of storms and cold that doesn't seem to want to end any time soon

[A-L-E-X]

I wish the Euro showed 250 mb jet, but PDII had us in the right entrance of a jet streak which was also very adventageous.

How many snowstorms have delivered over 2 feet of snow in Baltimore, New York City (Im using JFK for reference) and Boston? PD2 is the only one that immediately comes to mind.

[A-L-E-X]

from straight out of the book.... all credits on this quote to K&U, btw..

"This storm developed during a winter during which a moderate El Nino was present and the NAO tended toward a negative value. That said, the storm actually developed in a period of winter where the El Nino was weakening and when the sign of the NAO was actually positive"

Nice find Jay, so the pattern actually went "inside out" when the big dog developed

[baroclinic_instability]

I will post what I posted in the Mid-Atlantic--it is great to get excited, but I would temper that excitement with the reality of the situation at hand. This is a tough forecast for the models to handle--very tough. Operational runs are almost useless beyond 100-120 hours.

Here is a good look at the GFS operational in the Pacific. Watch each wave disturbance break off the Pacific Jet then pass over the Eastern Pacific Ridge. The exact timing of these low amplitude features and how strong they eventually are is almost impossible for the models to accurately simulate--then more variability is thrown into the mix as they pass through the coastal ranges and dense mountain networks of BC. This is likely going to be some of the lowest verification scores of the models all winter with this pattern we are getting into.

http://weather.utah....fs004&r=PA&d=TS

[tornadojay]

Nice explanation! These type of storms have that slow precip creep up the coast that can drive you nuts.

No problem.. Always happy to try to explain as best I can.

How many snowstorms have delivered over 2 feet of snow in Baltimore, New York City (Im using JFK for reference) and Boston? PD2 is the only one that immediately comes to mind.

hmm.. I'd have to check that out.. not sure off the top of my head.

Nice find Jay, so the pattern actually went "inside out" when the big dog developed

For anyone who does not have the Northeast Snowstorms book by Kocin and Uccellini... I highly recommend you getting it.. you won't be dissapointed.. it is the ultimate book for nor'easters... I was lucky enough to have met both of them at the first tri-state weather confernce several years ago.. each of them signed my copy. Awesome stuff!!!

[TheTrials]

HPC 12z final update

12Z UPDATE... NEW GUIDANCE INCLUDING THE ECMWF HAS COME INTO

BETTER AGREEMENT WITH DAY 3 SUN PLAINS EVOLUTION WITH A BETTER

DEFINED SFC REFLECTION THAN THE 00Z ECMWF. THE FINAL FCST

INCORPORATES IDEAS FROM THE 12Z ECMWF/UKMET/CMC WITH THE GFS LESS

FAVORED AS IT IS ON THE DEEP SIDE OF THE SOLN SPREAD. UNCERTAINTY

REMAINS ABOUT AS HIGH AS BEFORE FOR THE REST OF THE FCST. THE

UKMET/CMC HAVE TRENDED TOWARD THE GFS SCENARIO OF PULLING A

SIGNIFICANT AMOUNT OF ENERGY SWWD INTO NWRN MEXICO BY DAY 5 TUE

THUS LEADING TO A MORE PROGRESSIVE/EWD WRN ATLC SYSTEM. HOWEVER

THE 12Z ECMWF MAINTAINS CONTINUITY... ALBEIT IN SLIGHTLY SLOWER

FORM... TOWARD A MORE CONSOLIDATED NRN STREAM MID LVL SYSTEM THAT

ULTIMATELY MAINTAINS AN EAST COAST SFC LOW ON THE WRN EDGE OF THE

GUIDANCE SPREAD. SOME TIMING/DETAIL DIFFS ARE NOTED WITH UPSTREAM

FEATURES WITH MORE DATA DESIRED BEFORE MAKING A CONFIDENT

ADJUSTMENT. FOR DAYS 4-7 THE FULL EVALUATION OF LATEST SOLNS IN

LIGHT OF SENSITIVITY OF THE FCST PATTERN FAVORS ONLY MINOR DETAIL

ADJUSTMENTS TO THE UPDATED PRELIM ISSUANCE.

[jm1220]

Nice find Jay, so the pattern actually went "inside out" when the big dog developed

The El Nino definitely had a role in developing PDII, as well as the Gulf, since the storm was a big rainmaker in So. Cal and it had a great tap directly from the tropics. We were fortunate to have that massive high in Quebec to keep the cold air in. When the snow started I think it was in the single digits. And it crawled north at most 10 mph. DC had over a foot of snow before we had a flake. The sleet came veeerrryyy close though at the end, and I had a few pellets mix in at the very end, but not enough to lower the totals at all. Still widespread 20"+ in this area. But for that much snow, it was quite boring. No real banding structure or anything like that-just continuous overrunning of that massive tropical tap into the cold dome.