Dec 24-25 Snowstorm part 2

[baroclinic_instability]

The overnight hours evolved as I expected... the good band of snow around midnight lifted northeast and left a large part of east-central and southeast Iowa with little to no snow the rest of the night. That's just the way this month has gone. My total was about 1.7 inches when I went to bed and it's still only 2.1 inches.

There is a band of heavy snow currently sinking southeast across the area. The snow rate must be high because just north of Cedar Rapids there are reports of 6 inches. The heavy band is actually right on top of me now, but there is hardly a flurry falling.

Surprised you aren't seeing better rates. That shouldn't last much longer.

[Chicago WX]

DMX and DVN have now popped WSWs for parts of their CWAs. Nice.

[hawkeye_wx]

The heavy band on radar reached me about 40 minutes ago. I am only now beginning to see a few more flakes. It's still barely snowing.

[Thundersnow12]

DVN

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE QUAD CITIES IA IL

345 AM CST FRI DEC 24 2010

DISCUSSION

SHORT TERM...TODAY AND TONIGHT...

SNOW EVENT UNDERWAY WITH MAIN UPPER WAVE SEEN ON W/V IMAGERY OVER

WEST CENTRAL MN...AND INTERACTING WITH SECONDARY VORT OVER SOUTH

CENTRAL IA ATTM. LEAD BANDED WAA SNOWS FROM NORTHWEST OF CID...TO

JUST NORTH OF THE QUAD CITIES...AND TO NEAR STERLING AND PRINCETON

IL. WILL PROBABLY BE SOME 2-3 INCH SNOW REPORTS AT SUNRISE UNDER

THESE AREAS...OR EVEN HIGHER. THE SNOW MORE PATCHY AND SPORADIC

SOUTH OF I80. BUT AS THE MID LEVEL/H7 MB LOW CONTINUES TO

CONSOLIDATE AND PIVOT RIGHT ACRS THE CWA TODAY AND INTO THE

EVENING...A WIDESPREAD AND LONG LIVED SNOW EVENT TO CONTINUE ACRS

THE ENTIRE CWA. AM SOMEWHAT WORRIED IF ADVISORY WILL HOLD IN THE

INDEPENDENCE...TO EAST CEDAR RAPIDS...TO THE CLINTON IA AREAS WITH

SOME 6-7+ INCH AMOUNTS LIKELY BUT WILL BANK ON LENGTH OF EVENT PAST

12 HRS WITH THESE SNOWFALL TOTALS OCCURRING BY MID FRI EVENING/03Z

SAT. ALSO FORCING PROGGED TO BE MORE WIDESPREAD BUT LESS INTENSE

LATER TODAY AS THE MID LEVEL WAVE PASSES...AS OPPOSED TO THE MORE

ROBUST AND CONCENTRATED FORCING OVERNIGHT IN THE CURRENT WAA BANDS.

BUT SOUNDINGS AND BUFKIT ANALYSIS SUGGEST A DEEPENING SATURATED LAYER

OF ALMOST 200 MB IN THE FAVORED -10 TO -20 C LAYER FOR DENDRITIC

ACTIVITY THIS AFTERNOON AND INTO THE EVENING. EVEN LIGHT TO MODERATE

LIFT WITH THESE PROFILES WILL MEAN ADDITIONAL ACCUMULATIONS OF 1-4

INCHES JUST IN THE AFTERNOON AND EARLY EVENING. WILL RAISE THE POPS

TO CATEGORICAL FROM 00Z-06Z SAT ACRS THE SOUTHEAST HALF FOR LINGERING

LIGHT SNOW AND ADDITIONAL LIGHT ACCUMULATIONS UP TO AN INCH AS SLOW

MOVING UPPER WAVE LINGERS BEFORE IT FINALLY WEAKENS AND ROLLS

SOUTHEAST AFTER 06Z. THE EASTERN I80 CORRIDOR EAST OF THE QUAD CITIES

TO PRINCETON IL MAY EXPERIENCE 1-2 INCHES OF ADDITIONAL ACCUMULATION

FROM 00Z-06Z SAT.

WILL CONTINUE THE ADVISORY FOR NOW FOR THE ENTIRE AREA BUT STRESS

THE HIGHER END AMOUNTS. WIDESPREAD 3-6 INCHES...WITH THE ABOVE

MENTIONED AREA ALONG AND NORTH OF I80 OF 4-7 INCHES. IF ACCUMULATING

SNOW LOOKS TO INDEED LINGER LONGER ACRS THE EAST AND SOUTHEAST...THE

ADVISORY WILL HAVE TO BE EXPANDED IN TIME THROUGH POSSIBLY 06Z SAT.

SFC WINDS NOT TO INCREASE TO AROUND 10 KTS TIL LATE TONIGHT AFTER

09Z.

[janetjanet998]

DVN CW

0618 AM SNOW S AURORA 42.62N 91.73W

12/24/2010 E6.0 INCH BUCHANAN IA TRAINED SPOTTER

VERY LIGHT SNOW CONTINUES.

northern IA

0658 AM SNOW 3 SW MASON CITY AIRPORT 43.13N 93.38W

12/24/2010 M9.0 INCH CERRO GORDO IA TRAINED SPOTTER

0613 AM SNOW FOREST CITY 43.26N 93.64W

12/24/2010 M8.0 INCH WINNEBAGO IA LAW ENFORCEMENT

6 INCHES TO 3 AM ... 2 MORE SINCE THEN.

[Chicago WX]

0658 AM SNOW 3 SW MASON CITY AIRPORT 43.13N 93.38W

12/24/2010 M9.0 INCH CERRO GORDO IA TRAINED SPOTTER

[Thundersnow12]

LOT

EARLY MORNING WATER VAPOR/PROFILER DATA DEPICTS MID LEVEL SHORT WAVE

TROUGH MOVING ACROSS THE UPPER MIDWEST...WITH LOW LEVEL WARM

ADVECTION RESPONSE DEVELOPING ACROSS THE MID/UPPER MISSISSIPPI AND

LOWER MISSOURI RIVER VALLEYS. REGIONAL RADAR MOSAIC INDICATES AREA

OF WARM ADVECTION PRECIPITATION FROM SOUTHERN MN/NORTHERN IA

EXTENDING SOUTHEAST INTO NORTHWEST AND CENTRAL IL AT 07Z...WITH SFC

OBS SHOWING SNOW REACHING THE SURFACE WITH MORE VIGOR JUST OFF TO

THE WEST AND SOUTHWEST OF THE WFO CHICAGO CWA WITH SFC VISIBILITIES

IN THE 1-2 MILE RANGE IN SEVERAL SPOTS AND BELOW A MILE IN A FEW AS

WELL. NEAR TERM MODEL DEPICTIONS INDICATE THAT THIS RADAR DETECTABLE

PRECIPITATION IS DEVELOPING IN A REGION OF MODEST ISENTROPIC ASCENT

AND FRONTOGENESIS. GUIDANCE CONTINUES TO LIFT BAND OF SNOW NORTHEAST

ACROSS MUCH OF THE CWA THIS MORNING...AS UPPER MIDWEST SHORT WAVE

BEGINS TO DIG SOUTHEAST. SFC RIDGE AXIS CURRENTLY ACROSS WI/IL WITH

SFC DEW POINT TEMPS IN THE 20S...AND 00Z RAOBS FROM SEVERAL UPSTREAM

SITES DO DEPICT DRY AIR IN LOW LEVELS BELOW AROUND 700 HPA.

PERSISTENT LIFT HELPING TO SATURATE THINGS FROM THE TOP DOWN HOWEVER

AS EXEMPLIFIED BY GRADUALLY LOWERING CLOUD BASES ACROSS W/SW CWA AND

OF COURSE BY THE SNOW REACHING THE GROUND INTO WESTERN IL AS NOTED

ABOVE. GUIDANCE IN OVERALL AGREEMENT IN SPREADING AREA OF WAA/FGEN

FORCED LGT SNOW ACROSS AREA DURING THE MORNING...BEFORE SPREADING A

PERHAPS MORE WIDESPREAD REGION OF LIGHT/MODERATE SNOW SOUTHEAST

ACROSS THE AREA THIS AFTERNOON/EVENING WITH ACTUAL MID LEVEL

DISTURBANCE. MID LEVEL TROUGH AXIS EVENTUALLY PASSES SOUTHEAST

ACROSS THE AREA LATE TONIGHT...ALLOWING SNOW TO DIMINISH LATE

EVENING AND AFTER MIDNIGHT.

SOME CONCERN ABOUT INITIALLY DRY LOW LEVELS...WITH WRF-NAM RUNS

PARTICULARLY PARCHED ESPECIALLY ACROSS SOUTH/SOUTHEAST COUNTIES OF

CWA UNTIL LATER IN THE DAY. WRF APPEARS TO BE UNDERDOING AERIAL

EXTENT OF CURRENT SNOW BEING REPORTED AT SFC HOWEVER...SO HAVE

GENERALLY MORE TOWARD A BLEND OF QPF FROM SREF/GFS/ECMWF FOR

SNOWFALL AND LIQUID EQUIVALENTS WITH AN AVERAGE SNOW/LIQUID RATIO OF

AROUND 15:1 PER BUFKIT/COBB DERIVED GUIDANCE. THIS RESULTS IN SNOW

AMOUNTS THROUGH 12Z SATURDAY OF ROUGHLY 2-3 INCHES ACROSS CHICAGO

AND NORTHWEST INDIANA...INCREASING TO 4+ INCHES ACROSS SOUTHWEST

PORTIONS OF ADVISORY COUNTIES ALONG WEST/SOUTHWEST CWA BORDER. THIS

FITS GOING ADVISORY WELL...THUS FOR NOW WILL MAINTAIN HEADLINE AS

ORIGINALLY ISSUED.

[janetjanet998]

DSM

INCLUDING THE CITIES OF...FOREST CITY...NORTHWOOD...GARNER...

MASON CITY...CLARION...HAMPTON...ALLISON...WAVERLY...

WEBSTER CITY...ELDORA...GRUNDY CENTER...WATERLOO...MARSHALLTOWN...

TOLEDO

638 AM CST FRI DEC 24 2010

..WINTER STORM WARNING IN EFFECT UNTIL 6 PM CST THIS EVENING

THE NATIONAL WEATHER SERVICE IN DES MOINES HAS ISSUED A WINTER

STORM WARNING FOR HEAVY SNOW...WHICH IS IN EFFECT UNTIL 6 PM CST

THIS EVENING. THE WINTER WEATHER ADVISORY IS NO LONGER IN EFFECT.

* SHORT TERM TRENDS...LIGHT TO MODERATE SNOW CONTINUES ACROSS MOST

OF NORTHERN AND NORTHEASTERN IOWA. THE BULK OF THE ACCUMULATING

SNOWFALL WILL OCCUR THROUGH MID MORNING TODAY...WITH LIGHT SNOW

PERSISTING THEREAFTER THROUGH THE AFTERNOON.

* STORM TOTAL SNOW ACCUMULATIONS...SNOWFALL TOTALS WILL GENERALLY

RANGE FROM 6 TO 9 INCHES WITH LOCALLY HIGHER AMOUNTS POSSIBLE.

OVERNIGHT TOTALS HAVE GENERALLY BEEN 5 TO 7 INCHES WITHIN THE

WARNING AREA...AND ANOTHER 1 TO 3 INCHES IS EXPECTED TODAY.

DVN

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE QUAD CITIES IA IL

648 AM CST FRI DEC 24 2010

...WINTER STORM WILL IMPACT HOLIDAY TRAVEL WITH SIGNIFICANT

ACCUMULATING SNOW THROUGH THIS EVENING...

.A STRONG DISTURBANCE IN THE NORTHERN PLAINS WILL CONTINUE TO

SPREAD ACCUMULATING SNOW ACROSS ALL OF THE REGION TODAY AND INTO

THE EVENING. WIDESPREAD SNOW ACCUMULATIONS OF 3 TO 6 INCHES CAN

BE EXPECTED WITH ISOLATED HIGHER AMOUNTS POSSIBLE. AREAS GENERALLY

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

RECEIVE 5 TO 8 INCHES OF NEW SNOWFALL BY THIS EVENING. WIND

SPEEDS WILL BE FAIRLY LIGHT DURING THE SNOW...BUT GIVEN THE

EXPECTED POWDERY NATURE OF THE SNOW...DRIFTING MAY OCCUR IN OPEN

OR RURAL AREAS ESPECIALLY LATER TONIGHT.

IAZ040>042-051>054-065-066-242300-

/O.UPG.KDVN.WW.Y.0010.000000T0000Z-101225T0000Z/

/O.NEW.KDVN.WS.W.0004.101224T1248Z-101225T0000Z/

BUCHANAN-DELAWARE-DUBUQUE-BENTON-LINN-JONES-JACKSON-CEDAR-CLINTON-

INCLUDING THE CITIES OF...INDEPENDENCE...MANCHESTER...DUBUQUE...

VINTON...CEDAR RAPIDS...ANAMOSA...MAQUOKETA...TIPTON...CLINTON

648 AM CST FRI DEC 24 2010

..WINTER STORM WARNING IN EFFECT UNTIL 6 PM CST THIS EVENING

THE NATIONAL WEATHER SERVICE IN THE QUAD CITIES HAS ISSUED A

WINTER STORM WARNING FOR HEAVY SNOW...WHICH IS IN EFFECT UNTIL

6 PM CST THIS EVENING. THE WINTER WEATHER ADVISORY IS NO LONGER

IN EFFECT.

[janetjanet998]

this storm is overchieving

]

now both the 06 NAM and GFS have speckles of .5 QPF (60 hour) from NE MO to ORD

[hawkeye_wx]

I know with snow there can be a delay between the time a band moves over on radar and when it actually starts snowing, but this time it took an hour... pretty odd. It's now snowing moderate to low end heavy with good size flakes and it continues to increase.

[mnchaser]

Very close to 5 inches here, Which takes us over the 50 inch mark on the year...We shattered the all time December Snowfall record here in Mankato with this system!

Honestly we are setting ourselves up for a down right nasty blizzard probably nobody on this board has experienced..All it will take now is a nice 8"+ storm with some good winds and I'd say welcome back to the 70s Southern MN. We have been lucky so far..Only one of these storms have packed winds with it.

[A-L-E-K]

this storm is overchieving

]

now both the 06 NAM and GFS have speckles of .5 QPF (60 hour) from NE MO to ORD

things are going to have to start pushing north for ORD to get in on that, dry flow doing a great job killing the action over NE Illinois, but enchanced band down around I80 is going to dump.

[csnavywx]

Just woke up to moderate snow with large dendrite aggregates. Almost no wind outside. These things are piling up quite fast. Didn't expect this type of snow rate this early on.

[A-L-E-K]

Just woke up to moderate snow with large dendrite aggregates. Almost no wind outside. These things are piling up quite fast. Didn't expect this type of snow rate this early on.

Really nice enhanced band organizing, 6" reports should be widespread inside this area LOT needs to add WWA for their southern counties further east and could upgrade far southwest to warnings given upstream reports and organizing band.

[csnavywx]

Really nice enhanced band organizing, 6" reports should be widespread inside this area

Models were right on with the DGZ being very deep. Have some 1/2" to 1" diameter aggregates out there.

[janetjanet998]

southern cook and eastern Will may be the big winner perhaps a foot

they will get in that band soon and may not stop snowing for 18+ HOURS....then the LES kicks in later

[A-L-E-K]

Models were right on with the DGZ being very deep. Have some 1/2" to 1" diameter aggregates out there.

It's going to be painful watching you get pummeled all day while i hang high and dry, luckily this pattern that has kept far NE Illinois in a dry flow is about to be blown wide open. You should see 4"+ easy based on the way that band is setting up.

[csnavywx]

southern cook and eastern Will may be the big winner perhaps a foot

they will get in that band soon and may not stop snowing for 18+ HOURS....then the LES kicks in later

Yeah, noticed that the NAM doesn't move the snow out until about 12Z tomorrow, later near the lake, with very a very prominent banding signature that stretches well inland.

[A-L-E-K]

southern cook and eastern Will may be the big winner perhaps a foot

they will get in that band soon and may not stop snowing for 18+ HOURS....then the LES kicks in later

Yep, they will overlap between the box I drew above and the LES. Going to get smoked. Cook county may have a 12" gradient when all is said and done.

oh yeah, lol @ LOT for not hoisting some kind of headlines for that area.

[michsnowfreak]

Pict or it didn't happen

According to S MN climate summaries, snow depths for 12/23 ranged from 12" in Chanhassen (suburban minny) and St Cloud, to 16" in Minneapolis, to 26" in Rochester

[csnavywx]

Yep, they will overlap between the box I drew above and the LES. Going to get smoked. Cook county may have a 12" gradient when all is said and done.

oh yeah, lol @ LOT for not hoisting some kind of headlines for that area.

"Dry ring" on the composite reflectivity is shrinking pretty fast. Snow falling down to about 2kft over/near the LOT radar, so I would expect that you start to see some consistent flakes in the next several hours.

[janetjanet998]

looks like some waek echoes lredy over the lke moving inland ner the IL/IN border

perhaps some weak lake enhancment even for the system snow

[A-L-E-K]

"Dry ring" on the composite reflectivity is shrinking pretty fast. Snow falling down to about 2kft over/near the LOT radar, so I would expect that you start to see some consistent flakes in the next several hours.

Yeah i didn't mean to say i won't see flakes from this, this just make like the 4th enhanced band that will get shunted to my southwest.

FWIW 12z NAM seems to have initialized the band over you too far south, so it's probably going to underdo your QPF, as odd as it sounds to use NAM and underdo QPF in the same sentence.

[A-L-E-K]

looks like some waek echoes lredy over the lke moving inland ner the IL/IN border

perhaps some weak lake enhancment even for the system snow

This has been hinted at for some time and is the wild card for my area.

[csnavywx]

Yeah i didn't mean to say i won't see flakes from this, this just make like the 4th enhanced band that will get shunted to my southwest.

FWIW 12z NAM seems to have initialized the band over you too far south, so it's probably going to underdo your QPF, as odd as it sounds to use NAM and underdo QPF in the same sentence.

Yeah, at least the wetter trend has been consistently there for the past few runs, so in my book, while the actual QPF might've been underdone, at least there was an indication that it was likely going to be that way.

[janetjanet998]

NAM has .5 inch precip next 24 hours..but as Alek pointed out i think tht my be up near I-80

Mod-heavy snow down in MO(Cou SN+) west in IRK(SN) north in RFD (SN)

central IL in a snow hole

[Cyrys]

The MSP airport should be very close to a new December snowfall record. Since that heavier band last night set up over the heart of the metro last night, the far southwest metro missed on the heavier totals. I'm at around 2.5" for the storm.

[A-L-E-K]

NAM has .5 inch precip next 24 hours..but as Alek pointed out i think tht my be up near I-80

Mod-heavy snow down in MO(Cou SN+) west in IRK(SN) north in RFD (SN)

central IL in a snow hole

Central IL caught between systems. Really like the area between 88 and 80 in Illinois for the next 6hrs or so to pile up some nice totals.

[janetjanet998]

MO

0811 AM SNOW ASHLAND 38.77N 92.26W

12/24/2010 M4.0 INCH BOONE MO TRAINED SPOTTER

STILL SNOWING AT THIS TIME

0821 AM SNOW 1 W CUBA 38.06N 91.41W

12/24/2010 M4.0 INCH CRAWFORD MO TRAINED SPOTTER

STILL SNOWING

[A-L-E-K]