Jan 20th snow event part 2

[Chicago Storm]

LOT

LEVEL FGEN FORCING FARTHER TO THE NORTHEAST...BUT STILL DEALING WITH

SATURATING THE DRIER LOW LEVEL AIR. MAIN CONCERNS WITH THE FORECAST

FOR THIS AFTERNOON WILL BE DEALING WITH A SOUTHWARD TREND IN THE

MODELS FOR AXIS OF HEAVIEST QPF AND COMPLEX PHASING/INTERACTIONS

WITH SOUTHERN LOW PRESSURE SYSTEM. MOST GUIDANCE HAS TRENDED THE

AXIS OF HEAVIEST QPF SLIGHTLY FARTHER SOUTH...INTO PORTIONS OF

NORTHERN WILL COUNTY AND KENDALL COUNTY. GUIDANCE ALSO IN GOOD

AGREEMENT WITH OMEGAS PEAKING MID AFTERNOON INTO EARLY EVENING

WITH RATES OF AN INCH PER HOUR POSSIBLE DURING THIS

PERIOD...PARTICULARLY BETWEEN THE I-90 AND I-80 CORRIDORS. FOR

TOTAL SNOWFALL TODAY...DID MODERATE FORECAST SNOW RATIOS A

BIT...LOOKING AT AN AVERAGE OF 14-15:1 OVER SIX HOUR PERIOD THIS

AFTERNOON...BUT AT LEAST TEMPORARILY WE COULD BE LOOKING AT HIGHER

RATIOS FOR A SHORT WHILE. THIS WILL RESULT IN SNOW TOTALS OF 4 TO

7 INCHES PRETTY MUCH CENTERED DOWN THE I-88 CORRIDOR. WITH NO

MAJOR CHANGES TO GOING FORECAST...WILL NOT MAKE ANY ADJUSTMENTS TO

THE GOING WINTER WEATHER HEADLINES AT THIS TIME BUT DID SLIGHTLY

BUMP UP SNOW TOTALS SOUTH OF THE CURRENT WARNED AREA...EXPECTING

HIGHER END ADVISORY SNOWS ACROSS PORTIONS OF NORTHERN WILL COUNTY

AND KENDALL COUNTY...AS WELL AS LAKE AND PORTER COUNTIES IN

INDIANA. SECONDARY ISSUE WILL BE INTERACTIONS WITH A LOW PRESSURE

SYSTEM MOVING ACROSS THE MID MISSISSIPPI VALLEY LATER THIS

EVENING. GUIDANCE SUGGESTS THAT SOME OF THE STRONGER SYNOPTIC

FORCING AS NOTED BY Q-VECTOR CONVERGENCE WILL SHIFT FARTHER

SOUTH...WITH SOME GUIDANCE EVEN HINTING THAT HEAVIER SNOWS WILL

SHIFT ACROSS THE SOUTHERN PORTION OF THE CWA. BASED ON MODELS POOR

ABILITY TO HANDLE SUCH SITUATIONS...CONFIDENCE IS SOMEWHAT LOW ON

HOW THINGS MAY PLAY OUT THIS EVENING...AND WILL HAVE TO MONITOR

SHORT TERM TRENDS CLOSELY.

[BowMeHunter]

Yeah, and it should be mostly pixie dust unless the heavier bands sw of Madison somehow make it in here.

Should do better than pixie for a little while i would hope but I haven't looked at radar and normally never do during an event so i dunno know for sure. I knew we'd be fighting the pixie battle for a while to start.

[BeastFromTheEast]

Yeah, and it should be mostly pixie dust unless the heavier bands sw of Madison somehow make it in here.

Heavy snow at MSN! 0.25 mile visibility, and the best stuff isn't even here yet!

No pixie dust in bands >20DBZ. I'm sure it would only get better northeast of here where it's even colder aloft.

???

Wazz good Wi-Wx?

[cyclone77]

No pixie dust in bands >20DBZ. I'm sure it would only get better northeast of here where it's even colder aloft.

[turtlehurricane]

???

I see why he's saying it's pixie dust, but it's alot of pixie dust. Also it's not the needle pixie dust or anything, just a bunch of individual flakes with no aggregation since it's so cold. I'll go out soon and check the exact structure.

The airport is indeed reporting hvy snow: http://mesowest.utah.edu/cgi-bin/droman/meso_base.cgi?stn=KMSN&unit=0&timetype=LOCAL

[buckeye]

Could end up being an ice storm for parts of Central Ohio tonight...

ILN not impressed....for Franklin county they are saying 1" of snow tonight, an inch or less tomorrow and a tenth of an inch of ice. Your graph above would be a full fledge icestorm

[BowMeHunter]

lol wiwx was refering to your amplify snow flake size glasses.. Lots of WOTY canadates from this subforum next yr.

[wisconsinwx]

I see why he's saying it's pixie dust, but it's alot of pixie dust. Also it's not the needle pixie dust or anything, just a bunch of individual flakes with no aggregation since it's so cold. I'll go out soon and check the exact structure.

The airport is indeed reporting hvy snow: http://mesowest.utah...&timetype=LOCAL

I can only speak for here. I'm sure it's legit mod to heavy snow in MSN. It does look to be expanding and have enough of an ENE movement to come in here for awhile.

[daddylonglegs]

Couple inches out there... light as can be. Must be a very high ratio. Its one of those you could shovel with a broom.

2F right now... Not sure we are going to hit 11F like they say.

[weatherbo]

LOT

LEVEL FGEN FORCING FARTHER TO THE NORTHEAST...BUT STILL DEALING WITH

SATURATING THE DRIER LOW LEVEL AIR. MAIN CONCERNS WITH THE FORECAST

FOR THIS AFTERNOON WILL BE DEALING WITH A SOUTHWARD TREND IN THE

MODELS FOR AXIS OF HEAVIEST QPF AND COMPLEX PHASING/INTERACTIONS

WITH SOUTHERN LOW PRESSURE SYSTEM. MOST GUIDANCE HAS TRENDED THE

AXIS OF HEAVIEST QPF SLIGHTLY FARTHER SOUTH...INTO PORTIONS OF

NORTHERN WILL COUNTY AND KENDALL COUNTY. GUIDANCE ALSO IN GOOD

AGREEMENT WITH OMEGAS PEAKING MID AFTERNOON INTO EARLY EVENING

WITH RATES OF AN INCH PER HOUR POSSIBLE DURING THIS

PERIOD...PARTICULARLY BETWEEN THE I-90 AND I-80 CORRIDORS. FOR

TOTAL SNOWFALL TODAY...DID MODERATE FORECAST SNOW RATIOS A

BIT...LOOKING AT AN AVERAGE OF 14-15:1 OVER SIX HOUR PERIOD THIS

AFTERNOON...BUT AT LEAST TEMPORARILY WE COULD BE LOOKING AT HIGHER

RATIOS FOR A SHORT WHILE. THIS WILL RESULT IN SNOW TOTALS OF 4 TO

7 INCHES PRETTY MUCH CENTERED DOWN THE I-88 CORRIDOR. WITH NO

MAJOR CHANGES TO GOING FORECAST...WILL NOT MAKE ANY ADJUSTMENTS TO

THE GOING WINTER WEATHER HEADLINES AT THIS TIME BUT DID SLIGHTLY

BUMP UP SNOW TOTALS SOUTH OF THE CURRENT WARNED AREA...EXPECTING

HIGHER END ADVISORY SNOWS ACROSS PORTIONS OF NORTHERN WILL COUNTY

AND KENDALL COUNTY...AS WELL AS LAKE AND PORTER COUNTIES IN

INDIANA. SECONDARY ISSUE WILL BE INTERACTIONS WITH A LOW PRESSURE

SYSTEM MOVING ACROSS THE MID MISSISSIPPI VALLEY LATER THIS

EVENING. GUIDANCE SUGGESTS THAT SOME OF THE STRONGER SYNOPTIC

FORCING AS NOTED BY Q-VECTOR CONVERGENCE WILL SHIFT FARTHER

SOUTH...WITH SOME GUIDANCE EVEN HINTING THAT HEAVIER SNOWS WILL

SHIFT ACROSS THE SOUTHERN PORTION OF THE CWA. BASED ON MODELS POOR

ABILITY TO HANDLE SUCH SITUATIONS...CONFIDENCE IS SOMEWHAT LOW ON

HOW THINGS MAY PLAY OUT THIS EVENING...AND WILL HAVE TO MONITOR

SHORT TERM TRENDS CLOSELY.

Models have been hinting at this since yesterday.

[blue60007]

Snowing at a decent clip here.

[Hoosier]

Weenie goggles.

I think we're all snow...very little to no taint. We're not far off I guess, I'll ride 2-3" and call it a day.

I gotta leave less than 2" on the table given the stingier Euro/NAM qpf and possible brief mixing but the actual ongoing trends don't look bad. Gonna ride 1-3"

[McDude]

that microcast on abc is going to be out of their viewing area by the time they run it this evening.

[hawkeye_wx]

About 2.5 inches here. Radar returns to my west are beginning to thin out, so I don't think we can get to 4 inches.

[Gilbertfly]

solid SN down in bolingbrook. . .

[Chicago Storm]

skilling going wtih 4-9" still.

[cyclone77]

Back down to high end light/low end moderate, but still nice dendrites. Somewhere in the 2-3" range. QC just about completely dry slotted now.

[Chicago WX]

I gotta leave less than 2" on the table given the stingier Euro/NAM qpf and possible brief mixing but the actual ongoing trends don't look bad. Gonna ride 1-3"

Seems fair. I don't think we'll mix though. Snowing pretty good right now...fleeting as it will be.

[wisconsinwx]

Have yet to see anything above 15 dbz here. Once we do, the pixie dust will thicken and turn into legit flakes.

[Hoosier]

Seems fair. I don't think we'll mix though. Snowing pretty good right now...fleeting as it will be.

I doubt it as well but you know how those sneaky undermodeled warm layers can go. 35-40 dbz to the west. If that's all snow...

[cyclone77]

2.4" as of noon.

[Geos]

Have yet to see anything above 15 dbz here. Once we do, the pixie dust will thicken and turn into legit flakes.

Needs to warm up - too cold for big flakes! A wind off the lake would do it!

[turtlehurricane]

I saw a mixture of small, and often broken dendrites, with probably columns mixed in. This indicates to me that the supply of cloud water droplets is lacking aloft from the dry air, cause we have perfect conditions for snow growth temp wise.

Still snowing at a good clip despite that, 0.05" of liquid in the past hour and 0.07" storm total.

20-25 dBZ echoes about to move in, perhaps that's where there's more moisture available and there's real dendrites.

[Hoosier]

If only this would last

[Gilbertfly]

[PatrickSumner]

IWX isn't so worried about the dry air. Actually going to raise snow totals in there southern counties...

UPDATE...

REGIONAL RADAR MOSAIC CONTINUES TO SHOW INTENSIFYING BAND OF SNOW

FROM EAST CENTRAL IOWA INTO NORTH CENTRAL ILLINOIS. THIS ZONE OF

STRONGER ISENTROPIC ASCENT WILL OVERSPREAD NORTHERN HALF OF AREA

LATER THIS AFTERNOON INTO TONIGHT. A FEW REPORTS OF 5 TO 6 INCHES

OF SNOW ACCUMULATION ALREADY HAVE BEEN REPORTED ACROSS NORTHWEST

IOWA. STILL SOME CONCERN FOR SOME AREAS RECEIVING WARNING CRITERIA

ACCUMULATIONS BY LATE EVENING. NAM/GFS ISENTROPIC PROGS CONTINUE

TO INDICATE SOME SLIGHT WEAKENING OF ISENTROPIC UPGLIDE AS

STRONGEST FORCING FROM EASTERN IOWA/NORTHERN ILLINOIS TRACKS INTO

NORTHERN INDIANA AS NORTHERN VORT MAX ACROSS IOWA/SOUTHERN

MINNESOTA TENDS TO GET MORE SHEARED ACROSS THE SOUTHERN GREAT

LAKES REGION. WILL CONTINUE TO ASSESS 12Z DATA AND OBSERVATIONAL

TRENDS BUT AT THIS TIME WILL MAINTAIN A HIGHER END WINTER WEATHER

ADVISORY FOR SNOW ACCUMULATIONS OF 4 TO 7 INCHES. PERIOD OF MOST

INTENSE SNOWFALL RATES STILL APPEARS TO BE IN THE 21Z-03Z

TIMEFRAME WHEN ISENTROPIC LIFT IS MAXIMIZED ALONG WITH AN

INCREASINGLY FAVORABLE COLOCATION OF DENDRITIC GROWTH ZONE AND

UPWARD MOTION. ONLY OTHER TWEAK TO FORECAST WAS TO CONTINUE TREND

OF INCREASING SNOWFALL AMOUNTS ACROSS SOUTHERN HALF OF CWA. SOME

INDICATIONS IN HRRR OUTPUT OF SECONDARY BANDED AREA OF SNOW DEVELOPING

LATER THIS EVENING ACROSS LOCATIONS FURTHER SOUTH AS LOW LEVEL

FRONTOGENESIS BEGINS TO INCREASE IN RESPONSE TO SECONDARY UPPER

LEVEL WAVE PROGRESSING THROUGH THE CENTRAL PLAINS THIS AFTERNOON.

[vortex]

NATIONAL WEATHER SERVICE QUAD CITIES IA IL

1157 AM CST FRI JAN 20 2012

.UPDATE...

WITH AXIS OF HEAVIEST SNOWFALL BECOMING APPARENT...HAVE EXTENDED

WINTER STORM WARNING FURTHER SOUTH...TO REACH FROM CID ACROSS THE

NORTHERN QUAD CITIES METRO...EAST INTO WHITESIDE COUNTY IL.

STRONG ELEVATED WARM ADVECTION/CONVERGENCE/FRONTOGENESIS HAS SET UP

IN A W-NW TO E-SE AXIS FROM NW IA THROUGH EAST CENTRAL IA INTO W

CENTRAL IL. RADAR AND SHORT TERM MODELS CONFIRM A WAVE RIPPLING

ALONG THIS BAROCLINIC AXIS CURRENTLY MOVING THROUGH EASTERN

IA...AND ANOTHER FURTHER UPSTREAM OVER NW OR N CENTRAL IA. HEAVY

SNOW HAS BEEN FALLING FOR THE PAST SEVERAL HOURS FROM DBQ W TO

INDEPENDENCE WITH MODERATE TO OCCASIONALLY HEAVY SNOW SOUTH TO

WHAT APPEARS TO BE THE WHAT WILL BE THE PRIMARY DELINEATION OF

SNOW TO LITTLE OR NO SNOW. THIS IS ROUGHLY FROM VINTON SE ACROSS

NORTHEAST JOHNSON COUNTY...SOUTHERN CEDAR COUNTY...AND NORTHERN

SCOTT IN IA...AND PORT BYRON TO PRINCETON IN IL.

CONSIDERING THE RATE AT WHICH SNOW IS FALLING AND THE UPPER LEVEL

FORCING CONTINUING WELL THROUGH THE AFTERNOON...WIDESPREAD 6 TO 8

INCH SNOW AMOUNTS ARE LOOKING MORE LIKELY OVER THE WARNING AREA

FROM THIS MORNING...AND ROUGHLY A ROW OF COUNTIES FURTHER

SOUTH WHERE THE WARNING HAS BEEN EXPANDED...BASED ON THE ABOVE

MENTIONED TRENDS. BASED ON CURRENT SNOWFALL RATES AND

TRENDS...TOTALS WELL OVER 8 INCHES WILL BE POSSIBLE BETWEEN THE

HIGHWAY 20 AND HIGHWAY 30 CORRIDORS.

[Chicago WX]

If only this would last

Nice. Make due with what we got. Good flake size...maybe a half inch before it moves out. Bonus to my earlier thinking/fears.

[Chicago Storm]

12z ECMWF

Excluding 12-18z precip...

LSE: 0.11"

MSN: 0.26"

MKE: 0.30"

SBM: 0.14"

CID: 0.12"

DVN: 0.13"

PIA: 0.09"

RFD: 0.32"

ORD: 0.44"

MDW: 0.43"

DEC: 0.06"

VPZ: 0.40"

LAF: 0.19"

IND: 0.20"

MIE: 0.25"

OKK: 0.25"

FWA: 0.33"

HAO: 0.20"

DAY: 0.25"

CMH: 0.24"

TDZ: 0.36"

CLE: 0.33"

MKG: 0.22"

GRR: 0.24"

BTL: 0.34"

ADG: 0.38"

DTW: 0.31"

PHN: 0.20"

YKF: 0.13"

YYZ: 0.11"

[cyclone77]

So far just a trace in Muscatine Iowa. Areas just south of the QC have a dusting at best. One hell of a range along the southern edge. People on FB in the QC are already questioning forecast amounts. Sure was/is a tough forecast.