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Quick thump potential Wed night (12/7-12/8/11)


snowgeek

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They really don't expect a changeover until 6Z?

My point and click for here actually says rain/snow until 2 AM then snow.... what model are they looking at?

And they don't even have an advisory up for my neighbor across the field in the Western Schenectady County zone.

WITH REGARD TO TONIGHT/S STORM...THE FIRST ISSUE WILL BE UPDATING

THE CURRENT SUITE OF WINTER WEATHER STATEMENTS EARLY THIS

AFTERNOON. LATEST 12Z/NAM CONTINUES TO SUGGEST HEAVY

QPF...ALTHOUGH LINGERING A BIT LONGER...PAST 06Z...WHEN THE COLDER

AIR ARRIVES. EXTREME MID LEVEL F-GEN SUGGESTS THAT...WHEN THE

CHANGEOVER TO SNOW OCCURS...IT COULD BE VERY HEAVY...EVEN IF FOR

ONLY A COUPLE OF HOURS. CAN NOT RULE OUT SNOWFALL RATES OF 2-3

INCHES/HOUR...OR EVEN HIGHER...WITHIN THE FIRST HOUR OR TWO AFTER

CHANGEOVER. NOW...SHOULD THE PRECIP LINGER ONLY AN HOUR OR MORE

THAN CURRENTLY EXPECTED...HIGHER TOTAL SNOWFALL AMOUNTS COULD

EASILY BE REACHED...PERHAPS ALMOST DOUBLE WHAT IS CURRENTLY

INDICATED. WILL ASSESS THIS VERY CLOSELY OVER THE NEXT 1-3

HOURS...PENDING OUTPUT FROM THE GFS AND ALSO TRENDS FROM THE

HRRR/RUC 13...AND ENHANCED SHORT TERM WRF. SHOULD HIGHER AMTS SEEM

LIKELY...UPGRADES TO WIDESPREAD ADVISORIES...AND WARNINGS MAY BE

NEEDED.

How do you spell BOOOOOYAAAAAAA!

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6Z looks late for a changeover, especially for you! Lots of catch up going on with this one!

They really don't expect a changeover until 6Z?

My point and click for here actually says rain/snow until 2 AM then snow.... what model are they looking at?

And they don't even have an advisory up for my neighbor across the field in the Western Schenectady County zone.

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Yup... waiting patiently........ ok - maybe impatiently... :popcorn:

They really don't expect a changeover until 6Z?

My point and click for here actually says rain/snow until 2 AM then snow.... what model are they looking at?

And they don't even have an advisory up for my neighbor across the field in the Western Schenectady County zone.

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WITH REGARD TO TONIGHT/S STORM...THE FIRST ISSUE WILL BE UPDATING

THE CURRENT SUITE OF WINTER WEATHER STATEMENTS EARLY THIS

AFTERNOON. LATEST 12Z/NAM CONTINUES TO SUGGEST HEAVY

QPF...ALTHOUGH LINGERING A BIT LONGER...PAST 06Z...WHEN THE COLDER

AIR ARRIVES. EXTREME MID LEVEL F-GEN SUGGESTS THAT...WHEN THE

CHANGEOVER TO SNOW OCCURS...IT COULD BE VERY HEAVY...EVEN IF FOR

ONLY A COUPLE OF HOURS. CAN NOT RULE OUT SNOWFALL RATES OF 2-3

INCHES/HOUR...OR EVEN HIGHER...WITHIN THE FIRST HOUR OR TWO AFTER

CHANGEOVER. NOW...SHOULD THE PRECIP LINGER ONLY AN HOUR OR MORE

THAN CURRENTLY EXPECTED...HIGHER TOTAL SNOWFALL AMOUNTS COULD

EASILY BE REACHED...PERHAPS ALMOST DOUBLE WHAT IS CURRENTLY

INDICATED. WILL ASSESS THIS VERY CLOSELY OVER THE NEXT 1-3

HOURS...PENDING OUTPUT FROM THE GFS AND ALSO TRENDS FROM THE

HRRR/RUC 13...AND ENHANCED SHORT TERM WRF. SHOULD HIGHER AMTS SEEM

LIKELY...UPGRADES TO WIDESPREAD ADVISORIES...AND WARNINGS MAY BE

NEEDED.

How do you spell BOOOOOYAAAAAAA!

NWS Albany was a little slow to catch on this time around. The ECMWF and the NAM agreed that this would be more than a 1-3" event 24 hrs ago, and that's usually a pretty reliable combination. That said, this event is really a matter of "threading the needle", so it would not have made sense to issue watches and advisories yesterday when there was still a good chance of seeing either mostly rain or an out-to-sea solution.

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Report back when the changeover is achieved there. :)

Okay. The National Weather Service is really downplaying this. I think Tompkins County should be under an advisory, considering there is a reasonable chance we will meet the criteria of 4 inches.

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They really don't expect a changeover until 6Z?

My point and click for here actually says rain/snow until 2 AM then snow.... what model are they looking at?

And they don't even have an advisory up for my neighbor across the field in the Western Schenectady County zone.

Agreed...not sure what they're using for a basis of their changeover times. My point forecast said after 3am...when the 6z runs suggested between 10pm-1am. Latest NAM supports even an earlier changeover...closer to 10pm. I do think they are seeing that thus the language in the discussion about the possibility of amounts double the current forecast...but seems like they don't want to buy into it just yet. Looks like GFS is a tick warmer than the NAM for 12z...but even still...probably drops 0.5" of QPF after the changeover. They are gonna need WWA's for the valley and warnings for the higher terrain in my opinion. Even my 2-4" for the valley would bust low if the NAM verified. A blend of the NAM and GFS probably supports 3-6" in the valley, 6-10" for high terrain.

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000

WWUS41 KALY 071709

WSWALY

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE ALBANY NY

1209 PM EST WED DEC 7 2011

MAZ001-025-NYZ058-063-VTZ013-014-080100-

/O.UPG.KALY.WW.Y.0023.111207T2300Z-111208T1100Z/

/O.NEW.KALY.WS.W.0014.111207T2300Z-111208T1100Z/

NORTHERN BERKSHIRE-SOUTHERN BERKSHIRE-WESTERN GREENE-

WESTERN ULSTER-BENNINGTON-WESTERN WINDHAM-

INCLUDING THE CITIES OF...PITTSFIELD...NORTH ADAMS...

GREAT BARRINGTON...LEE...LENOX...HOUSATONIC...HUNTER...

TANNERSVILLE...WINDHAM...SUNDOWN...ELLENVILLE...WOODSTOCK...

WEST HURLEY...KERHONKSON...NAPANOCH...PHOENICIA...BENNINGTON...

JACKSONVILLE...NEWFANE

1209 PM EST WED DEC 7 2011

...WINTER STORM WARNING IN EFFECT FROM 6 PM THIS EVENING TO 6 AM

EST THURSDAY...

THE NATIONAL WEATHER SERVICE IN ALBANY HAS ISSUED A WINTER STORM

WARNING FOR HEAVY SNOW...WHICH IS IN EFFECT FROM 6 PM THIS

EVENING TO 6 AM EST THURSDAY. THE WINTER WEATHER ADVISORY IS NO

LONGER IN EFFECT.

* LOCATIONS...CENTRAL AND SOUTHEAST CATSKILLS...BERKSHIRES AND

SOUTHERN GREEN MOUNTAINS.

* HAZARD TYPES...HEAVY SNOW.

* ACCUMULATIONS...5 TO 10 INCHES OF SNOW ACROSS THE SOUTHERN

BERKSHIRES AND BENNINGTON COUNTY...6 TO 12 INCHES OF SNOW ACROSS

THE NORTHERN BERKSHIRES AND CENTRAL AND SOUTHEAST

CATSKILLS...AND 8 TO 16 INCHES OF SNOW ACROSS WESTERN WINDHAM

COUNTY.

* TIMING...RAIN CHANGING TO SNOW THIS EVENING AND CONTINUING

THROUGH TONIGHT.

* IMPACTS...SNOW COVERED ROADS.

* WINDS...BECOMING NORTHWEST THIS EVENING AT 5 TO 15 MPH WITH

GUSTS UP TO 25 MPH OVERNIGHT.

* TEMPERATURES...IN THE MID TO UPPER 30S THIS EVENING...DROPPING

INTO THE UPPER 20S BY THURSDAY MORNING.

* VISIBILITIES...GENERALLY ONE QUARTER TO ONE MILE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER STORM WARNING MEANS SIGNIFICANT AMOUNTS OF SNOW...

SLEET...AND ICE ARE EXPECTED OR OCCURRING. STRONG WINDS ARE ALSO

POSSIBLE. THIS WILL MAKE TRAVEL VERY HAZARDOUS OR IMPOSSIBLE.

&&

$$

NYZ047-051-VTZ015-080100-

/O.CON.KALY.WW.Y.0023.111207T2300Z-111208T1100Z/

SCHOHARIE-WESTERN ALBANY-EASTERN WINDHAM-

INCLUDING THE CITIES OF...COBLESKILL...MIDDLEBURGH...ALTAMONT...

BRATTLEBORO...WEST BRATTLEBORO...BELLOWS FALLS

1209 PM EST WED DEC 7 2011

...WINTER WEATHER ADVISORY REMAINS IN EFFECT FROM 6 PM THIS

EVENING TO 6 AM EST THURSDAY...

* LOCATIONS...THE SCHOHARIE VALLEY...HELDERBERGS...AND EXTREME

SOUTHEAST VERMONT.

* HAZARD TYPES...MODERATE SNOW.

* ACCUMULATIONS...3 TO 6 INCHES OF SNOW...EXCEPT 4 TO 8 INCHES OF

SNOW ACROSS EXTREME SOUTHEAST VERMONT.

* TIMING...RAIN CHANGING TO SNOW THIS EVENING...WITH SNOW

CONTINUING THROUGH THE NIGHT.

* IMPACTS...SNOW COVERED ROADS.

* WINDS...BECOMING NORTHWEST THIS EVENING AT 5 TO 15 MPH WITH

GUSTS UP TO 25 MPH OVERNIGHT.

* TEMPERATURES...IN THE MID TO UPPER 30S THIS EVENING...DROPPING

INTO THE UPPER 20S BY THURSDAY MORNING.

* VISIBILITIES...GENERALLY ONE HALF TO ONE MILE.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

A WINTER WEATHER ADVISORY MEANS THAT PERIODS OF SNOW...SLEET...OR

FREEZING RAIN WILL CAUSE TRAVEL DIFFICULTIES. BE PREPARED FOR

SLIPPERY ROADS AND LIMITED VISIBILITIES...AND USE CAUTION WHILE

DRIVING.

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After seeing the full 12z suite...I don't think I'm confident enough to raise my call in Albany from 2-4". NAM is the juiciest and changes us over the earliest. But mostly everything suggests the heaviest banding stays south and gives us maybe 0.5" QPF after the switch. Would love for the NAM to win this one...but I'm not sure I see it happening. So 2-4" for the valley...I'll still say 4-8" in the higher elevations (especially south of ALB).

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It can't be snowing in Binghamton. 850's are still above freezing and its not even snowing in Ithaca yet.

Well there's no sounding data out of Binghamton to say what the 850s are right now. Heavier precip rates over Binghamton compared to Ithaca means better dynamic cooling. You see this all the time in borderline situations...change over to snow with heavy precip then back to light/ran drizzle when intensity lets up.

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Well there's no sounding data out of Binghamton to say what the 850s are right now. Heavier precip rates over Binghamton compared to Ithaca means better dynamic cooling. You see this all the time in borderline situations...change over to snow with heavy precip then back to light/ran drizzle when intensity lets up.

The BGM reporting station is the Binghamton Airport / NWS Office, which sits over 1600 feet ASL in the Town of Maine. Below is the NWS Office webcam showing the snow already starting to accumulate on the grass and vehicles...

http://www.erh.noaa.gov/bgm/webcam/

webcamfront.png?1323283906305

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Well 2-4" ain't so shabby considering the pattern and lack of cold air. My gut tells me that the heavier banding will get into the CD. I'm going for 3-6" in the valley and 5-9" in the Helderberg's. Did you see the Euro?

After seeing the full 12z suite...I don't think I'm confident enough to raise my call in Albany from 2-4". NAM is the juiciest and changes us over the earliest. But mostly everything suggests the heaviest banding stays south and gives us maybe 0.5" QPF after the switch. Would love for the NAM to win this one...but I'm not sure I see it happening. So 2-4" for the valley...I'll still say 4-8" in the higher elevations (especially south of ALB).

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12z NAM seems to want to bring the banding into ALB...can we flip early enough to take advantage?

I think so. What we are seeing here is a classic case where the models (namely the GFS) is too warm aloft because it doesn't properly account for the dynamical cooling that will take place as melting snow falls through the column of the atmosphere. If the precipitation rate is strong enough, this effect will overcome the initial warm nose.

I actually think the 12z NAM has a really realistic senario in regards to the potential changeover time. As the very heavy precipitation rates moves into the region, we should see this start to cool the column. Check out the sounding animation I made for the 12z NAM.

2m7vjph.gif

Starting at 18z (an hour ago), you can see the significant warm nose currently in place over Albany. However, also notice the significant layer of nearly isothermal temperatures above 850mb. This is the melting snow layer that is already causing a part of the column to cool to freezing. This seems like an accurate solution, given the amount of bright banding we are already starting to see on radar as the precipitation increases. If the NAM is correct with the precipitation intensity, this will only increase as we progress into the afternoon. Notice that as time progresses between 21z and 00z the isothermal layer starts to do a number on the warm nose aloft. While there is some weak warm air advection, the dynamical cooling that should be underway could very well overpower this signal, since the advection is not very intense between 850mb and 925mb. By 02z, the 850mb low finally starts to get better organized, and you notice that the wind vector orientation starts to shift around the northwest. The NAM promptly responds by creating a fully isothermal layer without evidence of a warm nose aloft over Albany by 02z (9pm). At this point, heavy wet snow will likely be falling, which will finally cause the boundary layer to cool to near freezing (by 03z).

The GFS seems to have no concept of this dynamical cooling element in its soundings. This could be due to the lower overall precipitation expected, which would limit the potential of the melting snow cooling the column. The ECWMF decidedly sides with the NAM as opposed to the GFS, and I think this is a logical solution at this time, considering the expected precipitation rates and the evidence of melting snow already occurring given the radar reflectivity signature.

Basically, I think Albany is in store for at least a 3-6 hour period of heavy snow, and the changeover time will be key to how much the lower elevations end up receiving. I'd error on the higher side of guidance given these forecast soundings, especially if the mesoscale banding sets up directly over the Capitol District. If the banding remains south of the region, not only will the amounts be reduced, but so will the amount of cooling in the column, so this is a case where temperature and precipitation totals are strongly correlated.

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The NAM and the ECMWF agree more about the 850 temperature cooling below 0C in ALB between 00z and 03z. The GFS is probably wrong with waiting until after 03z..it seems to have a warm bias with low-level temps. The bigger question is the banding...the ECMWF has the best banding setting up just southeast of ALB.

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The NAM and the ECMWF agree more about the 850 temperature cooling below 0C in ALB between 00z and 03z. The GFS is probably wrong with waiting until after 03z..it seems to have a warm bias with low-level temps. The bigger question is the banding...the ECMWF has the best banding setting up just southeast of ALB.

Yep... this is the million dollar question (as it always is for snowstorms in nor-easters). Its very difficult to know ultimately where the final mesoscale band will set up. If its right over KALB, this will be a significant heavy wet snowstorm that will probably be on the upper end of advisory criteria (and warning criteria in the mountains). If the mesoscale band sets up southward (like the October snowstorm), then we end up with significantly less snowfall, and perhaps a later changeover time given less melting snowfall bringing down the isothermal layer aloft.

At this point, the ECWMF based on the 3hr QPF maps has the band setting up just to our SE here in metro Albany, but we are close enough to pick up .25-.35" QPF in a three hour period, which isn't too shabby and should drop at least advisory criteria snowfall (given a 8-10:1 ratio). Shift this band northward by 20-30 miles though and we go up above .5" for multiple 3 hour periods!

212srhy.png

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The NAM and the ECMWF agree more about the 850 temperature cooling below 0C in ALB between 00z and 03z. The GFS is probably wrong with waiting until after 03z..it seems to have a warm bias with low-level temps. The bigger question is the banding...the ECMWF has the best banding setting up just southeast of ALB.

Just about to post that in response to phil's post. EC and NAM do agree on timing of changeover...but not on the setup of the best banding. And I didn't see any other 12z guidance other that the NAM that supported the best banding setting up over the capital region...everything else was just S & E. If 18z holds, maybe its on to something...but I wouldn't be shocked to see it slide a bit south. So while I agree ALB should change over by 10pm tonight...if the heaviest banding set up to the south...I can't see us with anymore than 2-4". If best banding does set up around here...then you can double that forecast.

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Just about to post that in response to phil's post. EC and NAM do agree on timing of changeover...but not on the setup of the best banding. And I didn't see any other 12z guidance other that the NAM that supported the best banding setting up over the capital region...everything else was just S & E. If 18z holds, maybe its on to something...but I wouldn't be shocked to see it slide a bit south. So while I agree ALB should change over by 10pm tonight...if the heaviest banding set up to the south...I can't see us with anymore than 2-4". If best banding does set up around here...then you can double that forecast.

I completely agree with this! Its all about the mesoscale banding at this point.

The NAM does have some support from the HRRR, except its a couple hours faster with the mesoscale band setup over KALB. Still not too bad of an agreement.

344uvpx.png

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Welcome to the board! You'll probably want to be in different Upstate forums depending on the storm. The general forum is good for medium and long range outlooks. New England has a very active and informative forum.

Hey guys, I'm new here and thought that my first chance at measurable snowfall this year would be a good time to join. I'm from Allentown, PA but am in Ithaca for college(Cornell). Is this where all the CNY people hang out? It seems like there are regional cliques even within the regional subforums.

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