12/3-12/6 MW/GL snow event?

[A-L-E-K]

the LOT overnight AFD had some quality nuggets, including this bit about ratios which sound pretty solid.

DENDRITIC GROWTH ZONE CURRENTLY APPEARS TO BE JUST ABOVE THE FAVORED

OMEGA...LIFT...AREA AT ONSET. THEN DGZ LOWERS BY 09-12Z SAT INTO THE

BETTER OMEGA LYR. THIS PERIOD OF TIME IS WHEN OUR CWFA WILL OBSERVE

THE STEADIER SNOWFALL. SNOW RATIOS ARE PEGGED BTWN 11/1 TO A MAX OF

19/1. WITH DECLINING PWAT WITH THIS SYSTEM...FEEL A SLIGHTLY HIGHER

RATIO WOULD FIT BETTER. STORM TOTALS CURRENTLY ARE IN LINE WITH HIGH

END ADVISORY CRITERIA...HOWEVER WE ARE STILL NEARLY 48 HRS OUT AND

THIS COULD FLUCTUATE IN EITHER DIRECTION.

[Thundersnow12]

right now Id bet on the highest totals from this being on the IA/MN border or so. models have been showing that area for days with the most QPF as it seems the storm will be slowly weakening as it heads southeast.

catching up and looking at the new runs now.

geez, LSX WRF really weakens it as it comes down.

http://www.crh.noaa.gov/lsx/wrf/wrfdisplay.php

[goknights]

The operational models seems to be trending drier yet the sref's seem to be trending juicier. Anyone with more knowledge clue me in on this?

[Stevo6899]

12z GFS is a bit drier. Only a small spot in northeast Iowa has a .50+ qpf. I still think with decent ratios there will be a 4-8 swath wherever the storm starts moving more south than east (heavy bands dont move much). Most likely southern minnesota and northern iowa. I think everywhere else there will be 3-5. Rich keep getting richer. Enjoy it

[prinsburg_wx]

12z RGEM a bit farther northeast. A day or two ago the GEM was the best model for CR, but the 12z has us down to only an inch or so. At least we'll finally get the first real accumulating snow of the season. We have all winter to get some bigger snows.

according to the 12Z RGEM...ND gets a small area with the highest qpf

[Thundersnow12]

according to the 12Z RGEM...ND gets a small area with the highest qpf

can you post the 60hr image?

[Chicago Storm]

can you post the 60hr image?

Only goes out to 48hrs.

[goknights]

No 60 hour image on the RGEM

[Thundersnow12]

Only goes out to 48hrs.

Oh ya duh.

DVN afd

LONG TERM...FRIDAY THROUGH NEXT WEDNESDAY

WILL MAINLY CONCENTRATE EFFORT ON THE POTENTIAL WINTER STORM AT THE

START OF THIS PERIOD. ASSESSING THE SUITE OF NEW 00Z RUN MODELS...

INCREASING CONFIDENCE FOR A HIGHER END ADVISORY OR EVEN A LOWER END

WARNING EVENT FROM LATE FRIDAY AFTERNOON THROUGH MIDDAY SATURDAY

ACRS THE NORTHEAST THIRD TO HALF OF THE DVN FCST AREA. HAVE GONE

MAINLY WITH THE CONSISTENT ECMWF IN FORCING...SPEED AND MOISTURE

FEEDS...WITH SOME REFERENCE TO THERMODYNAMIC PROFILES OF THE GFS.

ALSO FOR NOW...HAVE IGNORED THE SLIGHT NORTHEASTWARD JOG OF THE NEW

00Z RUN ECMWF WITH ITS FORCING AND DEF ZONE PRECIP PLACEMENT...AND

SHUNTED ITS PARAMETERS SOUTHWESTWARD AGAIN WHICH MATCHES THE OLDER

12Z RUN. ALL OTHER NEW MODEL RUNS HAVE TRENDED FURTHER SOUTH AND THE

NORTHWARD ADJUSTMENT OF THE 00Z EURO DOESN/T MAKE SENSE AT THIS

POINT. ELEVATED WAA WING OR LEAD ISENTROPIC LIFT SNOWS SHOULD

OVERSPREAD THE NORTHWESTERN CWA BY LATE FRI AFTERNOON...POSSIBLY

REACHING AS FAR SOUTH AS I80 BY SUNDOWN. THE CURRENTLY ACCEPTED

PROPAGATION PATH AND STRENGTH OF BOTH THE MID LEVEL WAVE AND LLVL

INVERTED TROF COMPLEX SUGGEST BULK OF THE SNOW ACCUMULATIONS TO

OCCUR BETWEEN 00Z-12Z SAT...WITH SOME LINGERING LIGHTER

ACCUMULATIONS OF AN INCH OR TWO EAST OF A DBQ TO QUAD CITIES LINE

FROM 12Z-18Z SAT. SATURATION OF THE PRIME -10 TO -20 C ICE NUCLEATION

LAYER OCCURS MAINLY FRI NIGHT AS WELL/ALTHOUGH FCST SOUNDINGS SUGGEST

IT IS A BIT HIGH FOR A LARGER DENDRITIC BURST/...WITH SOME POST-

WAVE MID LAYER DRYING OCCURRING SATURDAY. ALL IN ALL BY MIDDAY

SATURDAY TAKING INTO ACCOUNT THE ABOVE MENTIONED FAVORED MODEL

BLENDS...THE POTENTIAL IS THERE FOR 3-5 INCHES AND SOLID ADVISORY

CRITERIA ALONG AND NORTH OF A LINE FROM JUST NORTH OF VINTON AND

CEDAR RAPIDS IA...TO THE NORTHERN QUAD CITIES/CLINTON...AND TO 20

MILES SOUTH OF STERLING IL. IF ALL COMES TOGETHER WITH A MORE

ENHANCED MOISTURE FEED ALONG ADVECTIVE AND CONVERGENT ELEVATED THTA-

E WING...THERE COULD BE A SWATH OF 5-8 INCHES FROM MANCHESTER IA...

TO BELLEVUE...MT CARROLL AND FREEPORT. THIS LATEST THINKING TAKES

INTO ACCOUNT AN AVERAGE SLR 12:1 RATIO PROFILE FOR THE BULK OF THE

EVENT. WILL HOIST A PRELIMINARY WINTER STORM WATCH FOR AREAS ROUGHLY

ALONG AND NORTH OF A LINE FROM CEDAR RAPIDS...TO CLINTON AND TO SOUTH

OF STERLING. FOLLOWING DAY SHIFT MAY HAVE TO FINE TUNE WATCH FURTHER

IN AREAL COVERAGE AND AMOUNTS...AS THE WESTERN WAVE BECOME BETTER

SAMPLED BY UPPER AIR NETWORK WITH INLAND PROPAGATION.

[csnavywx]

can you post the 60hr image?

It only goes to 48 hours. Canadians don't bother with 48-84, and I tend to agree with their reasoning.

[Thundersnow12]

MKX

FRIDAY NIGHT THROUGH SAT NIGHT...FCST CONFIDENCE MEDIUM TO HIGH

A STRONG 500MB SHORTWAVE CROSSING THE NORTHERN PLAINS WILL REACH THE

DAKOTAS BY LATE FRI AFTERNOON...THEN DROP SOUTHEAST ACROSS IOWA FRI

NIGHT AND IL/IN ON SATURDAY. THIS SHORTWAVE WILL CREATE AN AREA OF

SFC LOW PRESSURE WHICH WILL TRACK ALONG AN 850MB BAROCLINIC ZONE

FROM SD TO IOWA TO IL. THE ASSOCIATED INVERTED TROUGH WILL FOCUS

850-700MB FGEN/WAA AND STRONG OMEGA OVER PORTIONS OF THE MIDWEST FRI

NIGHT THROUGH SATURDAY...BRINGING WIDESPREAD ACCUMULATING SNOW TO

SOUTH CENTRAL AND SOUTHEAST WISCONSIN.

THE GFS CONTINUES TO BRING THE SYSTEM ACROSS THE REGION THE

FASTEST...BRINGING PRECIP TO SE WI PRIOR TO 00Z SAT. THE NAM HAS THE

SLOWEST SOLN...AND THE ECMWF IS IN BETWEEN. BUFKIT MODEL SNDGS SHOW

A DEEP DENDRITIC SNOW GROWTH ZONE AROUND 150MB...CO-LOCATED OR JUST

ABOVE THE MAX OMEGA VALUES. THE GENERAL CONSENSUS FOR STRONGEST

FORCING OVER THE CWA SEEMS TO BE AROUND 06Z.

THERE IS THE POTENTIAL FOR LAKE ENHANCEMENT WITH THIS SYSTEM.

1000-850MB WINDS HAVE A SOUTHEASTERLY COMPONENT AT 00Z SAT...WHICH

BACKS EASTERLY 12-18Z SAT AND NORTHEASTERLY AFTER. THERE WILL BE A

DEEP LAYER OF DRY AIR TO OVERCOME NEAR THE LAKE EARLY IN THE

EVENT...BUT ONCE SATURATION OCCURS BY 06Z...THE LAKE WILL HAVE A

CHANCE TO PRODUCE ENHANCED SNOW AMOUNTS. DELTA T/S WILL BE AROUND

15-16C WITH A DEEP INVERSION HEIGHT. MODEL 1000-850MB CONVERGENCE IS

ALSO PINPOINTED ALONG THE LAKESHORE AREAS...ESPECIALLY FOR THE

12-18Z TIME PERIOD.

THERE IS STILL MODEL DISAGREEMENT IN QPF AMOUNTS FOR A GIVEN 6-HR

PERIOD...BUT THEY GENERALLY AGREE ON THE HIGHEST AMOUNTS DURING THE

00Z TO 06Z PERIOD FOR THE SOUTHWEST CWA AND THE 06-12Z FOR ALMOST

ALL OF THE CWA. ROEBBER/COBB SNOW RATIO METHODS AND MODEL GFS/NAM

SNOW RATIOS ARE IN PRETTY GOOD AGREEMENT OF THE EVENT BEGINNING WITH

13 TO 15:1 RATIOS AND THEN INCREASING TO 17 TO 18:1 RATIOS LATER.

WITH QPF TOTALS OF AROUND A HALF INCH IN SW CWA...0.35 TO 0.4 INCHES

IN SE CWA...AND A QUARTER INCH IN THE NE CWA...STORM TOTAL SNOW

AMOUNTS ADD UP TO ALMOST 8 INCHES IN SW CWA...5 TO 7 INCHES IN SE

CWA...AND 3 TO 4 INCHES IN NE CWA.

THESE AMOUNTS PAINT WARNING CRITERIA /GREATER THAN 6 INCHES/ IN SW

HALF OF CWA...SO WENT WITH WINTER STORM WATCH FOR SW CWA FOR 00Z SAT

TO 00Z SUN...BUT LEFT OUT RACINE/KENOSHA. CONFIDENCE OF ROLLING INTO

A WINTER STORM WARNING INSTEAD OF A WINTER WEATHER ADVISORY IN THE

CENTRAL PART OF THE CWA IS A LITTLE LOWER...BUT INCLUDED HALF IN THE

WATCH ANYWAY. ALSO...THE LAKE ENHANCEMENT POTENTIAL SEEMS

THERE...BUT WOULD LIKE TO WAIT ANOTHER MODEL RUN OR TWO TO ADD

RACINE/KENOSHA INTO A WATCH.

[Stevo6899]

"My prediction: there will either be a Snow Advisory or Winter Storm Watch issued for Chicagoland by the time I hit the air at 4:00." Mike Caplan on facebook. I would guess an advisory

[KeenerWx]

"My prediction: there will either be a Snow Advisory or Winter Storm Watch issued for Chicagoland by the time I hit the air at 4:00." Mike Caplan on facebook. I would guess an advisory

For sure only an advisory. This thing's going to die out as it heads east, or so it seems. Looks like Chicagoland should be good for 2-4", maybe some 5" in LOT's NW FA.

[A-L-E-K]

For sure only an advisory. This thing's going to die out as it heads east, or so it seems. Looks like Chicagoland should be good for 2-4", maybe some 5" in LOT's NW FA.

Pretty much my thinking as well without factoring in any lake enchancement, which for now looks meager.

[mnchaser]

What you know MN bullseye...

Not really? Sure some parts of MN have done pretty decent so far this year..But some places have also been screwed..for example anywhere east of I-35 has just been shafted, and if it wasn't for the 10 inches I received in one freak storm on Nov. 12-13, I would only have about 3 inches of snow on the year.

Your statement should really say, "What you know Northern MN isn't the bullseye on this one."

[Chicago Storm]

if it wasn't for the 10 inches I received in one freak storm on Nov. 12-13, I would only have about 3 inches of snow on the year.

Which is still more than just about all of us have.

[KeenerWx]

Pretty much my thinking as well without factoring in any lake enchancement, which for now looks meager.

Better than that 1/3", right?

[Chicago Storm]

Pretty much my thinking as well without factoring in any lake enchancement, which for now looks meager.

Looks like I will have to change my original call...

[Stevo6899]

Latest GGEM has it falling apart east of iowa also. Is it the NAO block thats forcing this thing to weaken and move south? Or the trough in the east left behind by the most recent storm?

[A-L-E-K]

Better than that 1/3", right?

Even better than a dusting though.

[Stebo]

Not really? Sure some parts of MN have done pretty decent so far this year..But some places have also been screwed..for example anywhere east of I-35 has just been shafted, and if it wasn't for the 10 inches I received in one freak storm on Nov. 12-13, I would only have about 3 inches of snow on the year.

Your statement should really say, "What you know Northern MN isn't the bullseye on this one."

Well I know that the majority of MN has been hit hard, the area east of 35 is a fraction of the land mass compared to the rest MN

[MadTown]

my thinkin is madison wi gets 4-5". I just don't see us getting into a WSW

[Moneyman]

How does the GGEM look? Euro better continue it's wet trend from last night, or it won't be looking good here.

[mnchaser]

Which is still more than just about all of us have.

I suppose, But take in account how much further south the majority of the members live, not exactly winter wonderland states.

[weatherbo]

http://www.sanfordlabs.com/WRF/82scale.png

Friday evening thru Sunday morning.

[Thundersnow12]

AREA FORECAST DISCUSSION...UPDATED

NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI

1034 AM CST THU DEC 2 2010

UPDATE

NEW 12Z NAM AND 12Z GFS HAVE TRENDED DOWN A BIT ON QPF FOR THE

FRIDAY NIGHT AND SATURDAY SNOW EVENT. NAM DOES FORM A MESO VORTEX

OVER LAKE MICHIGAN THAT BRINGS ENHANCED SNOW TO PORTIONS OF

WASHINGTON AND OZAUKEE COUNTY...BUT THIS BRINGS EVEN LESS SNOW TO

AREAS JUST TO THE SOUTH OVER MILWAUKEE. 700 MB RH ON THE NAM SHOWS

AREA OF 90 PCT RH FROM NORTHWEST TO SOUTHEAST ACROSS THE FORECAST

AREA...BUT STRUGGLES TO REACH 100 PCT. MODERATE Q VECTOR

CONVERGENCE IN 700 TO 500 MB REGION. MODERATE ISENTROPIC LIFT WITH

2 GRAMS/KG OVER THE FAR SOUTHWEST OF THE FORECAST AREA. CYCLONIC

SHEAR AXIS AT 500 MB IS FAVORABLE FOR THE SOUTHWEST HALF OF THE

FORECAST AREA.

ALL THINGS CONSIDERED CURRENT MODELS INDICATE A LIKELY HIGH END

ADVISORY EVENT MAINLY SOUTHWEST HALF OF THE FORECAST AREA ALONG

WITH LAKE ENHANCEMENT POTENTIAL...ESPECIALLY IF MESO VORTEX

DEVELOPS AS INDICATED ON THE NAM.

FOR NOW THINKING IS TO LEAVE CURRENT WATCH AS IS...BUT MAY MAKE

SOME CHANGES FOR THE AFTERNOON PACKAGE ONCE ALL MODELS/GUIDANCE

IS AVAILABLE.

[A-L-E-K]

http://www.sanfordla...WRF/82scale.png

Friday evening thru Sunday morning.

LE pretty evident there.

[MadTown]

beat me to it thundersnow

[Hoosier]

2-4" seems like a safe range for LAF. We moved out of the southern fringe with the 0z runs...which is nice. Looks like a good dumping for where the WSWs are lined up currently.

I might have to lower into the 2-4" range but I'm gonna wait a bit for further runs to confirm. Definitely still liking 6 to locally 9 or 10 to the northwest of here.

[Moneyman]

Euro:

we're out to 48... the system retrograding off the east coast has a stretched out 1000 mb low pressure.. the clipper has a light to moderate snow band from Minneapolis through Chicago.

Not sure if it's stronger or anything but that was from the euro thread.