XMAS Miracle: Blizzard of 2010 Lead-in Dialogue

[Collinsville]

I'm close to locking in 8-15 here in CT

Sounds good. I believe it will take at least 1.80" of precip to get 20".

[Bryan]

What are the odds some see Thunder Snow out of this? I realize that's usually more of a nowcast issue, just tossing it out there.

[weatherwiz]

Wind is a huge ratio killer. I'd stick to 11-12:1 personally. Seen it many times.

Even with ratios like that we should still make out quite well. Thanks for the heads up about the winds role, will take this into consideration.

[moneypitmike]

Guys this is all I'm saying on the NAM/GFS and to some extent the RGEM on the SW tail of this event, in six hours this is how much the speed and as a result the QPF field has changed. Look way to our sw near NC. The wet one was the 6z, 12z is the new GFS.

That would worry me a little at this range, could just be the models locking in, or they could be playing a game trying to catch up. The "pivot point" went from North Central PA at 6z to near Albany in a single run, another similar shift and our QPF totals here will begin to be effected.

Just something to watch is all, may be at end an end, may not be. Not saying it won't snow in Tolland or east cutty, don't care to be honest. Just saying, 3 for 3 on that change in one run. I need to stress is again for the ones that get all worked up when someone points something out and will accuse me of wrecking christmas, kicking their cats or stealing their chickens....just showing the output and something to watch for.... IF it happened again in 6 more hours and it's a real trend we will begin to compress the NW edge of the snow shield in SNE SE ward

A dose of sobriety.

[weatherwiz]

Sounds great, Ryan! I'm thinking along those lines as well. Pretty worried about the wind potential as well.

[mahk_webstah]

Kind of interesting, GYX's forecast. We are in WSW for a period of heavy snow and a period of moderate snow. But just west towards Hanover has just light snow and ne towards ossippee and Wolfeboro have light snow. the models seem to be slamming those areas though and perhaps even jackpotting them. And this is the forecast after the NAM but before the GFS

[shadow]

juts got home from work merry xmas to all and this storm this is looking sweet

[butterfish55]

Why in god's name hasn't this guy been given the boot?

I wish someone would make you a moderator.

**hint hint***

[Clinch Leatherwood]

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

1018 AM EST SAT DEC 25 2010

VALID DEC 25/1200 UTC THRU DEC 29/0000 UTC

...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR

INGEST...

12Z NAM EVALUATION

MODEL INITIALIZATION ERRORS ARE DESCRIBED UNDER THE RELEVANT

SYSTEM HEADING.

POTENTIAL EAST COAST STORM...

THE OBSERVED 250 MB WIND AND 500 MB HEIGHT AT LAKE CHARLES...WHERE

THE SMALL BUT POTENT SHORTWAVE IS FOUND...APPEAR TO BE INDICATIVE

OF THE SLIGHTLY DEEPER TROUGH RELATIVE TO THE NAM ANALYSIS. AS A

RESULT NAM 500 MB HEIGHTS ARE ABOUT 20 M HIGHER THAN ANALYZED AND

THE OBSERVED WINDS ARE 20 KNOTS LOWER THAN THE NAM ANALYSIS AT 250

MB...WHICH MIGHT REFLECT THE POSSIBILITY THAT THE HIGHER WIND

SPEEDS MAY BE LOCATED FARTHER SOUTH WITH THE SLIGHTLY DEEPER

TROUGH.

THERE DO NOT APPEAR TO BE SIGNIFICANT DIFFERENCES FROM EARLIER

VERSIONS OF THE NAM WITH THE JET STREAK/SHORTWAVE DROPPING

SOUTHWARD ACROSS THE PLAINS STATES THAT WILL LIKELY PHASE WITH THE

GULF LOW/TROUGH TO GENERATE THE INTENSIFYING CYCLONE.

LOW PRESSURE CURRENTLY IN THE GULF OF MEXICO HAS BEEN CONSISTENTLY

HANDLED BY THE OPERATIONAL NAM FOR THE PAST SEVERAL RUNS DATING

BACK TO YESTERDAY AFTERNOON. THE 12Z NAM IS CONSISTENT WITH THE

PAST 3 RUNS THROUGH AROUND SUNDAY AFTERNOON WHEN THERE IS SLIGHT

JOG FARTHER NORTHWARD AS THE LOW IS MOVING TOWARD SOUTHERN NEW

ENGLAND. SUCH A JOG WOULD HAVE SOME IMPLICATIONS...THOUGH

SLIGHT...IN THAT THE CYCLONE CENTER WOULD BE 20 TO 30 MILES

FARTHER NORTH NORTHWEST THAN PREVIOUS RUNS. WHILE THIS IS NOT A

LARGE CHANGE...IT IS STILL CONSISTENT WITH A TENDENCY FOR THE

SYSTEM TO BE CLOSER TO THE COAST THAN FARTHER EAST...AT LEAST FOR

THE NAM.

THE 12Z NAM SEEMS TO CLUSTER WELL WITH THE UKMET/CANADIAN RUNS BUT

CONTINUE TO BE FARTHER EAST OF THE RECENT GFS/NAEFS ENSEMBLE MEAN

AND OPERATIONAL SOLUTIONS AND SOMEWHAT FARTHER EAST THAN THE THE

00Z EUROPEAN AS WELL. JUST HAD A DISCUSSION THAT THE 09Z SREF

MEANS BRING HIGHER PRECIPITATION AMOUNTS INTO THE MID ATLANTIC

REGION...ANOTHER INDICATION OF THE WESTWARD DRIFT OF THE GFS

SOLUTIONS OVER THE PAST 24 HOURS THOUGH HAVE NOTHING TO DO WITH

THE 12Z NAM.

SHORTWAVE APPROACHING SOUTHERN CALIFORNIA...

THE NAM IS CONSISTENT WITH THE PREVIOUS 2 RUNS IN BRING THIS

SYSTEM INTO SOUTHERN CALIFORNIA BY SUNDAY MORNING WHILE BEING

FASTER THAN THE FORECAST ISSUED AT 18Z YESTERDAY.

MAJOR TROUGH MOVING TOWARD THE PACIFIC NORTHWEST SUNDAY INTO

MONDAY...

NAM IS CONSISTENT WITH EARLIER RUNS ON SUNDAY/DAY 1 BUT THEN

APPEARS TO ACCELERATE RELATIVE TO THE EARLIER MODELS BY MONDAY/DAY

2. 12Z NAM HAS SHORTWAVE AXIS OVER WESTERN MONTANA WHILE EARLIER

RUNS APPEAR FLATTER AND FARTHER WEST TOWARD WASHINGTON/OREGON.

THIS IS EVEN A MODEST CHANGE FROM THE 06Z RUN WHICH SHOWS MORE

WEST SOUTHWESTERLY FLOW OVER OREGON AND WASHINGTON AT 500 MB WHILE

WEST TO NORTHWESTERLY FLOW IS CURRENTLY SHOWN BY THE 12Z RUN. THE

SEA-LEVEL PRESSURE FIELDS ONLY SHOW SUBTLE DIFFERENCES WITH A LOW

IN MANITOBA FARTHER SOUTH THAN EARLIER RUNS AT 12Z MONDAY.

[SC48]

The situation with the 12Z GFS was at hour 48 the .5 inch band seperated too far from the center of the low. Unlike the prvious runs 6Z, the plume of moisture (.5") was mostly in Mass not southern New Hampshire, so knowing the bias of the GFS, the precipitation will be closer in than that far detached from the storm. Add that .5" amount to eastern Mass and you expand the purple color again. That's alll the really happened.

[Organizing Low]

with the latest runs, im trimming back my max amounts to 1-2 feet.

[dendrite]

Ryan--lock with double digits on the low-end. Ratios and consistently appropriate qpf makes it reaonable (though I understand being cautious on the public airwaves:).

Yeah...wind breaks the crystal structure all apart and you get the consistency of sugar blowing in your face. The Superstorm of '93 was documented to have inflated high ratios when it really wasn't the case. The precip gauges struggle to "catch" the snow in strong winds due to turbulence over the gauge. There were also some evaporational issues as well due to the heated gauge. It's a bit better now as they've gone over to weighing gauges at most ASOS sites. There's also wind screens to try to minimize the turbulence, but it only works so much. You'll still have some undercatch with 30-40mph+ winds. If you take a core sample from a representative area, melt it down, and measure it out you should get a decent water equiv value to determine your ratio.

[40/70 Benchmark]

Just in an anecdotal sense, so please don't send a calvary of H5 charts my way to prove me incorrect.....this event reminds me of Feb 2006 in the sense that it was a late party-conscensus and that the QPF is impressive, but nothing breath taking.

8-16" sounds right.

[adamrivers]

Wow we are going to slammed it seems. The max zone appears to be moving west? Oh this is awesome..

Seems to be headed right towards us now...... precip issues along the coast bigtime ....

[shadow]

I'm off today but I've locked in 8-15" here in CT. Near blizzard conditions are possible too.

now thats what i am talking about nice x mas gift

[40/70 Benchmark]

Seems to be headed right towards us now...... precip issues along the coast bigtime ....

Not really.....everyone outside of the cc canal is fine and E MA looks to be in the best spot.

[moneypitmike]

Just got word from my DC sister of her "suprise snow" falling outside her home in northern VA.

Sister in NYC just said "Snow? I didn't hear anything about that.....".

[Stevo6899]

Merry xmas everyone! Jealous I dont have anything to track here in michigan. LOL at all this lock it in stuff. Forget the models. Why do you conitnue to look at them? They have been off and on all week. They are pretty much useless in depicting phasing off the east coast. What makes you think they possibly wont phase too late on tonights 0z runs. The potential is there obviously but sit back relax and prepare to nowcast!

[MaineJayhawk]

Just got word from my DC sister of her "suprise snow" falling outside her home in northern VA.

Sister in NYC just said "Snow? I didn't hear anything about that.....".

Few know. People I talked to yesterday spoke of "some snow" but nothing like what is currently progged. I wanted to tell them that the tide was turning, but the initialization error fiasco made me gun shy. Not sure how many are going to be watching the news today.

[moneypitmike]

Who here is bothered by the hpc/messenger assessments?

I'm trouble a bit.

[dendrite]

12z Ukie maps...keep in mind no 6hr qpf at 42hr yet.

[Bostonseminole]

Merry xmas everyone! Jealous I dont have anything to track here in michigan. LOL at all this lock it in stuff. Forget the models. Why do you conitnue to look at them? They have been off and on all week. They are pretty much useless in depicting phasing off the east coast. What makes you think they possibly wont phase too late on tonights 0z runs. The potential is there obviously but sit back relax and prepare to nowcast!

merry x-mas.. I can't seem to get away from computer..

[MaineJayhawk]

12z Ukie maps...keep in mind no 6hr qpf at 42hr yet.

Crushing.

[Typhoon Tip]

I'm starting to get really worried on the GFS... it keeps showing this stupid V cutout for SNH.. Anyone know why its doing that?

...

Yes, I was just discussing that with a fellow Met on the phone ....

The GFS appears to be using hygrocscopic absorption of the QPF.

In other words, evaporationally robbing an interval of the action. I don't think that is outright correct considering that detail has limited support from the other guidance. On the other side, I can see that extremely rapid pressure falls down the coast would cause a pretty powerful ageostrophic response up this way, and that could very well cause more N component to the llv flow; if so, dry air entrained from the N could cause a kind of slanwise vertical deformation in PWAT. I actually remember a storm in the 1990s that did something like that.... It was one where the mid and upper levels closed off and the forecast was for a 'hook and latter' scenario, but when it backed in you could see billows of deep virga rumbling overhead in Lowell Mass with only flurries making it down to the SFC - they had to trunk the winterstorm warning back to only SE zones as a result, too. We were grandly pissed as Met student at the time, no doubt! But we had N winds there and dry dry dry just ate the damn thing alive - the sky turned orange at sunset as the western rim of the storm never made it to the Berkshires.

[HarveyLeonardFan]

If this thing trends any farther NW this will be similar to February 1995 for a lot of places from PVD on south that changed to rain.

[snowNH]

Yes, I was just discussing that with a fellow Met on the phone ....

The GFS appears to be using hygrocscopic absorption of the QPF.

In other words, evaporationally robbing an interval of the action. I don't think that is outright correct considering that detail has limited support from the other guidance. On the other side, I can see that extremely rapid pressure falls down the coast would cause a pretty powerful ageostrophic response up this way, and that could very well cause more N component to the llv flow; if so, dry air entrained from the N could cause a kind of slanwise vertical deformation in PWAT. I actually remember a storm in the 1990s that did something like that.... It was one where the mid and upper levels closed off and the forecast was for a 'hook and latter' scenario, but when it backed in you could see billows of deep virga rumbling overhead in Lowell Mass with only flurries making it down to the SFC - they had to trunk the winterstorm warning back to only SE zones as a result, too. We were grandly pissed as Met student at the time, no doubt! But we had N winds there and dry dry dry just ate the damn thing alive - the sky turned orange at sunset as the western rim of the storm never made it to the Berkshires.

In other words, We should be worried about that?

[weathafella]

Just ran MAV snow number. Other than the outer cape and ACK, some nice totals. HYA: 4+, EWB,PYM,TAN,BOS,BVY,BED,ORH,everything else in MA, 8+, NYC 8+, BWI 8+, PHL 8+, PWM 8+, AUG 6+. BOS,BVY,PWM etc have some additional beyond the first number. It's coming!

[moneypitmike]

12z Ukie maps...keep in mind no 6hr qpf at 42hr ye

How do those positions compare to 00z? Seems like it has quite the cut-off from PSF-ORE on qpf.

On the other hand, seems like it kinda stalls there doesn't it?

[Clinch Leatherwood]

The situation with the 12Z GFS was at hour 48 the .5 inch band seperated too far from the center of the low. Unlike the prvious runs 6Z, the plume of moisture (.5") was mostly in Mass not southern New Hampshire, so knowing the bias of the GFS, the precipitation will be closer in than that far detached from the storm. Add that .5" amount to eastern Mass and you expand the purple color again. That's alll the really happened.

I disagree cordially. Take a look at the band it had down in EVA on the old run, it's 150 miles NE this run. That's how much faster/more progressive this run is.

if it's moving to consensus fine, but the NAM was somewhat faster too. Just something to watch.

[Bryan]

Does anyone have a listing or map of the stations? I know BOS,ORH,PVD and all the main one but some I'm not sure of and would be nice to look and see where everyone is talking about geographically.