Dec 11-13 MW/Lakes/OV snow event part 4

[janetjanet998]

the .75,.5 and .25 QPF after 00z Sunday all moved/epanded a tad SW on the 06z vs 00z GFS In IL

[KeenerWx]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE NORTHERN INDIANA

447 AM EST SAT DEC 11 2010

SHORT TERM

DYNAMIC AND VRY COMPLEX WINTER STORM TO WREAK HAVOC ACROSS THE AREA

THIS WEEKEND.

OF NOTE IS ABRUPT SWD SHIFT SEEN IN ALL NCEP BASED 00Z MODEL

GUIDANCE. THIS ALIGNS MUCH BTR W/HEDGE PREFERENCE FM YDA FOLLOWING

GEM/UKMET BLEND AND LENDS GREATER CONFIDENCE GOING FORWARD ESP

W/NECESSITATED CHGS. WILL EXPAND ERN/SWRN EXTENT OF EXISTING WATCH

AND BACK START TIME TO 12Z SUN. WATER VAPOR THIS MORNING CLEARLY

CONFIRMS PRIOR GUIDANCE DISMAL HANDLING OF STG SW TROUGH DIGGING

SEWD THROUGH SRN NE THIS MORNING AND ALREADY SOUTH OF MANY 06Z MODEL

PROJECTIONS. 00Z CONSENSUS TURNED ABRUPTLY SOUTH AND HAVE CAUGHT ON

ALTHOUGH DOUBT ANY PARTICULAR PIECE OF MODEL BASED GUIDANCE OFFERS A

CONCRETE SOLUTION YET AS SWD DISPLACEMENT HAS PROBABLY NOT RUN ITS

FULL COURSE YET. THAT SAID...SWD SHIFT IN STG MID LVL DEFORMATION

ZONE XPCD AND MORE ACCURATELY PORTRAYED IN 00Z GEM FOLLOWED BY 03Z

SREF AND 00Z GEFS WHICH TAKE RAPIDLY DEEPENING SFC CYCLONE OVR NW IA

SEWD INTO WRN IN NR KLAF W/SECONDARY SFC DVLPMNT LT TONIGHT NR KJKL

THEN TURNS NWD TWD KCLE SUN AFTN. THIS WOULD PLACE MUCH OF CWA

SQUARELY WITHIN IMPRESSIVE TROWAL W/SIG SNOW ACCUMULATIONS SUN AND

SUN NIGHT. PROXIMITY OF 00Z MODEL BASED MID LVL DRY SLOT CONCERNING

BUT AGAIN GIVEN OBVIOUS ACROSS THE BOARD MODEL TREND FEEL QUITE

COMFORTABLE W/WATCH EXTENSION AND DAYSHIFT MAY NEED TO EXPAND

FURTHER TO ENCOMPASS NW OH.

CHG OVR THIS EVENING COMPLICATED W/ANOMALOUSLY STG WAA PUSH HWVR

VARIETY OF POINT SNDGS KEY IN ON SIG ADIABATIC ADJUSTMENT IN 03-06Z

TIMEFRAME COINCIDENT W/ARRIVAL OF DEEP LYRD ASCENT PLUME AND XPC A

RAPID CHANGE OVER W/ALL SNOW BY 06Z. AFT THAT...FCST BOILS DOWN TO

PLACEMENT OF STG MID LVL DEFORMATION ZONE AND HOW CLOSED MID LVL

TROUGH PIVOTS NORTH OUT OF THE OH VALLEY W/CONSENSUS BASICALLY

DUMBBELLING MID LVL TROUGH ARND CWA W/A PROLONGED PD OF MOD-HVY SNOW

ESP NORTH HALF AND RAPIDLY INCREASING GRADIENT FLW SUN AFTN BASED ON

CURRENT GUIDANCE SUITE AND THUS THE REASONING FOR WATCH EXPANSION.

MORE COMPLICATING FCTR LIES W/PLACEMENT OF LIKELY EXTREME LK

ENHANCED SNOW BAND W/BLEND OF HIGHRES GUIDANCE SLWR IN DVLPG INTENSE

SINGLE BAND SUN EVE AND THEN SLOWLY PIVOTING THIS EWD MON. EQL HGTS

NOTED NR 10 KFT AND LIKELY SEEDER-FEEDER MECHANISM ALOFT STILL IN

PLACE SUGGEST ADDNL SWD EXPANSION TO INCLUDE WHITE/CASS/AND MIAMI

COUNTIES PSBL BUT THIS IS QUITE RARE AND NOT INCLINED TO PUSH IT

THAT FAR SOUTH. OTHERWISE EWD PROGRESSION OF LK EFFECT HOLDS W/PRIOR

INITIAL WATCH YET DID EXTEND THROUGH 06Z TUE W/NEWER 06Z GUIDANCE

KEEPING THE ERN BAND W/LK SUPERIOR CONNECTION GOING WELL INTO TUE

AFTN AS INVERSION HGTS SLOW TO DROP GIVEN DOWNSTREAM BLOCKING

HOLDING FIRM AND DEEP MID LVL TROUGH STILL EXTENDING WWD THROUGH THE

LAKES. QPF GRIDS WEIGHTED TWD SYNOPTIC EVENT W/POTENTIAL LK EFFECT

CONTRIBUTION HEAVILY CONSERVED AS SOMEWHAT WAVERING PLACEMENT OF

BAND AND MORE IMPORTANTLY DURATION AS YET MOST UNCERTAIN AND TIED

DIRECTLY W/PLACEMENT OF MID LVL TROUGH AXIS AND TRACK/INTENSITY OF

SFC CYCLONE. NEVER THE LESS...SOME HIGHRES BASED GUIDANCE SUGGESTS

STORM TOTAL SNOW ACCUMULATIONS APCHG 30 INCHES OVR

LAPORTE/BERRIEN/ST JOE COUNTIES.

[MadTown]

La Crosse stickin with a wwa for southwest wisconsin

[Omahawx]

Winter weather advisory just issued for me for extensive blowing snow later on today and blizzard warning issued for Council Bluffs, IA

[KeenerWx]

GFS looks good for 2-4" @ home..a little less in West Lafayette.

Let it snow!

[KeenerWx]

LOT's new forecast graphic. Suggests about 6" back at home, but northeast portion of Porter county gets almost a foot. Definitely considering making a visit to home.

[Chicago Storm]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE NORTHERN INDIANA

447 AM EST SAT DEC 11 2010

WATER VAPOR THIS MORNING CLEARLY CONFIRMS PRIOR GUIDANCE DISMAL

HANDLING OF STG SW TROUGH DIGGING SEWD THROUGH SRN NE THIS MORNING

AND ALREADY SOUTH OF MANY 06Z MODEL PROJECTIONS. 00Z CONSENSUS

TURNED ABRUPTLY SOUTH AND HAVE CAUGHT ON ALTHOUGH DOUBT ANY PARTICULAR

PIECE OF MODEL BASED GUIDANCE OFFERS A CONCRETE SOLUTION YET AS SWD

DISPLACEMENT HAS PROBABLY NOT RUN ITS FULL COURSE YET. THAT SAID...

SWD SHIFT IN STG MID LVL DEFORMATION ZONE XPCD AND MORE ACCURATELY

PORTRAYED IN 00Z GEM FOLLOWED BY 03Z SREF AND 00Z GEFS WHICH TAKE

RAPIDLY DEEPENING SFC CYCLONE OVR NW IA SEWD INTO WRN IN NR KLAF

W/SECONDARY SFC DVLPMNT LT TONIGHT NR KJKL THEN TURNS NWD TWD

KCLE SUN AFTN.

Interesting.

[weatherbo]

from IWX:

GENERALLY 6 TO 10 INCHES OF SNOW ARE POSSIBLE WITHIN THE WATCH

AREA WITH HIGHER AMOUNTS OF 10 TO 20 INCHES AND LOCALLY HIGHER

AMOUNTS LIKELY NORTH AND WEST OF A LINE FROM WINIMAC TO WARSAW TO

THREE RIVERS.

damn impressive

[janetjanet998]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE MILWAUKEE/SULLIVAN WI

420 AM CST SAT DEC 11 2010

SHORT TERM

TODAY AND TONIGHT...CONFIDENCE...MEDIUM.

WATER VAPOR IMAGERY AND 500MB RUC ANALYSIS SHOW DIGGING SHORTWAVE

OVER NEBRASKA AND KANSAS EARLY THIS MORNING. STRONG TEMPERATURE

GRADIENT AND COLD AIR ADVECTION AT 500MB OVER EASTERN DAKOTAS/NE

WITH THE UPPER LOW...SHOWING GOOD POTENTIAL FOR RAPID DEEPENING. SFC

LOW PRESSURE CENTERED OVER WESTERN IOWA...AND RADAR SHOWING PRECIP

ASSOCIATED WITH INITIAL SURGE OF WARM AIR ADVECTION SPREADING ACROSS

CENTRAL MN...SE MN...AND WESTERN WI. WELL-DEFINED SPIRAL SHAPE IN

RADAR REFLECTIVITY OVER THE NE/IA BORDER WITH THE CENTER OF THE

LOW...AND ADDITIONAL POCKETS OF HEAVIER PRECIP ACROSS MUCH OF IOWA

AND MO. IMPRESSIVE TEMP GRADIENT WITH THE SFC COLD FRONT ACROSS

EASTERN NE. SPC MESOANAYSIS DEPICTING STRONG 850MB OVER SE

MN/EASTERN IA.

BAND OF HEAVIER PRECIP FALLING ALONG WESTERN CWA BORDER NEARLY

STATIONARY OVER THE PAST TWO HOURS WAS PRODUCING MAINLY SNOW

ACCORDING TO OBSERVERS AND ASOS. AHEAD OF THAT BAND...SOME OBSERVERS

REPORTED LIGHT FREEZING RAIN OR FREEZING DRIZZLE PRODUCING SOME

LIGHTLY GLAZED SURFACES WITHIN POCKETS OF THE LIGHTER RADAR RETURNS.

TEMPERATURES WILL WARM TO ABOVE FREEZING BETWEEN 8 AND 11 AM FOR

MUCH OF THE CWA THIS MORNING...THUS CUTTING OFF POTENTIAL FOR

FREEZING RAIN. RAIN WILL CHANGE TO SNOW AS THE SFC LOW MOVES ACROSS

NORTHERN IL...SLOWER TO CHANGE OVER IN THE SOUTHEAST CWA. MOST

CONFIDENCE IN ALL SNOW AFTER 00Z TONIGHT.

WINTER STORM WARNINGS FOR THE NW CWA AND ADVISORIES FOR FAR

SOUTHEAST CWA. CHANGED TIMING TO ACCOUNT FOR THIS INITIAL FREEZING

RAIN/SNOW IN NORTHEAST CWA...AND LATER CHANGE OF SNOW TO RAIN FOR

CENTRAL CWA.

SUNDAY AND SUNDAY NIGHT...FORECAST CONFIDENCE MEDIUM.

THE 500MB UPPER LOW WILL CONTINUE TO DEEPEN AS IT TRACKS ACROSS IL

AND INTO THE OHIO RIVER VALLEY ON SUNDAY. SFC PRESSURE IS EXPECTED

TO DEEPEN AS WELL DURING THIS TIME. NORTH TO NORTHWEST WINDS ON THE

BACK SIDE OF THE SFC LOW WILL INCREASE SIGNIFICANTLY OVER SOUTHERN

WI AROUND 12Z SUN. MODEL SNDGS SHOW MIXING TO AROUND 925MB/1500 FT

AT 18Z...ALLOWING 45 KT AT MSN AND 55KT AT MKE WINDS TO MIX DOWN. OF

COURSE THOSE WINDS WILL NOT REACH THE SFC...BUT THE GUST POTENTIAL

IS THERE. NORTHERLY WINDS 25 KT AT MSN AND 35 KT AT MKE WITH HIGHER

GUSTS LIKELY MIDDAY SUN.

THE SYSTEM SEEMS TO BE SLOWING DOWN...EACH MODEL RUN GETS SLOWER AND

THERE IS DECENT AGREEMENT ON ADDITIONAL ACCUMULATING SNOW. UP TO 2

INCHES IN NORTHEAST CWA AND AROUND AN INCH CENTRAL DURING THE

MORNING HOURS. SNOW TAPERING OF QUICKLY FROM WEST TO EAST THROUGH

EARLY AFTERNOON.

WITH SNOW STILL FALLING AND VERY STRONG NORTHERLY WINDS...BLOWING

SNOW WILL BRING VISIBILITIES DOWN TO DANGEROUS LEVELS AT TIMES. NEAR

BLIZZARD CONDITIONS WILL BE POSSIBLE IN OPEN AREAS. HOWEVER...WILL

NOT GO WITH BLIZZARD WATCH OR WARNING AT THIS TIME...AS IT LOOKS

LIKE THE MAJORITY OF THE AREA SHOULD NOT REACH FULL BLIZZARD

CRITERIA CONDITIONS. WINTER STORM WARNINGS WILL BE ABLE TO COVER

THESE HAZARDOUS CONDITIONS. STAY TUNED TO LATEST WSW FOR DETAILS.

[KeenerWx]

from IWX:

GENERALLY 6 TO 10 INCHES OF SNOW ARE POSSIBLE WITHIN THE WATCH

AREA WITH HIGHER AMOUNTS OF 10 TO 20 INCHES AND LOCALLY HIGHER

AMOUNTS LIKELY NORTH AND WEST OF A LINE FROM WINIMAC TO WARSAW TO

THREE RIVERS.

damn impressive

Enjoy, bud

[janetjanet998]

RUC continues its trend NORTH with the low

it did have iot over about IowaCity

now more like cedar falls

and then west of RFD at 03z

chicago dry slot

[weatherbo]

Enjoy, bud

[snowstormcanuck]

6z NAM is by far the coldest model run I've seen in the last 2-3 days. 6z RGEM/GFS not as much. I'm going with a call of 2" of wet snow here in Toronto, then a change to rain, and then a disgusting dryslut. Best trowal action looks to setup from Lk Huron through MI and back towards Chicago/S. WI. Enjoy your blizzard guys! I'm going back to bed.

[janetjanet998]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

429 AM CST SAT DEC 11 2010

DISCUSSION

345 AM...

THE TIME OF THE CALM BEFORE THE STORM IS DECREASING RAPIDLY.

FOR HEADLINES...WILL MAINTAIN THE WINTER STORM WATCH FOR SEVERAL

REASONS. THROUGH MUCH OF THE DAY TODAY...THE BULK OF THE

PRECIPITATION WILL BE RAIN. RAIN SHOULD CHANGE OVER TO A RAIN/SNOW

MIX AND THEN SNOW FOR THE ROCKFORD AREA THIS EVENING WITH THE SNOW

SPREADING EAST OVERNIGHT TONIGHT. THE HEAVIEST SNOW WILL BE WELL

NORTH OF THE CWA TONIGHT AND ONLY 2 TO 4 INCHES OF SNOW IS

EXPECTED TONIGHT...FOR THE NORTHERN TIER COUNTIES. FREEZING

DRIZZLE WILL BE THE CONCERN OVERNIGHT TONIGHT...PARTICULARLY FOR

THE CENTRAL AND SOUTHERN PORTIONS OF THE CWA...BUT THE EXACT

IMPACT OF THE FREEZING DRIZZLE AND THE AMOUNT OF GLAZING IS STILL

UNCLEAR...ESPECIALLY GIVEN THE WARMING TREND TODAY. THE EXACT

TRACK OF THE LOW CENTER WILL BE CRITICAL TO THE AMOUNT OF GLAZING.

AND THEN THERE IS THE STRONG WINDS THAT WILL DEVELOP AS THE

DEFORMATION SNOW BAND MOVES ACROSS THE AREA SUNDAY. BLOWING AND

DRIFTING SNOW WILL BE A SIGNIFICANT CONCERN AS WINDS APPROACH OR

EXCEED 40 MPH. THEN BY SUNDAY NIGHT AND MONDAY...ARCTIC COLD WILL

HIT THE ILLINOIS PORTION OF THE CWA AND LAKE EFFECT SNOW WILL HIT

THE NWRN INDIANA COUNTIES. WIND CHILL READING SHOULD REACH

ADVISORY CRITERIA AND MAY EVEN HIT WARNING CRITERIA IN SOME

LOCATIONS. LAKE EFFECT SNOW AMOUNTS MAY ALSO REACH WARNING

CRITERIA LEVELS FOR PORTER COUNTY AND POSSIBLY EVEN LAKE COUNTIES

IN INDIANA. SO...GIVEN THE DIVERSITY OF HEADLINE CRITERIA

PHENOMENA EXPECTED OVER THE NEXT FEW DAYS...WE FEEL THAT IT WOULD

BE BEST TO MAINTAIN THE WINTER STORM WATCH FOR A WHILE LONGER

UNTIL THE EXACT WARNING SITUATION BECOMES MORE CLEAR.

THE WEATHER PICTURE ASSOCIATED WITH THE LOW DEEPENING OVER THE

CNTRL PLAINS IS COMING INTO BETTER FOCUS THE CLOSER WE GET TO THE

EVENT. THE VARIOUS MODELS ARE COMING INTO A BETTER CONSENSUS...AT

LEAST FOR THE NEXT 24 HOURS...WITH THE TRACK AND MOTION OF THE LOW

CENTER. THE TREND OVER RECENT RUNS HAS BEEN FOR THE LOW CENTER TO

TRACK SLIGHTLY SOUTH AND A LITTLE SLOWER WITH EACH RUN. THE LATEST

00Z MODEL RUNS CONTINUE THIS TREND...WITH THE LOW CENTER MOVING

THROUGH NRN IL...RATHER THAN SRN WI AS WAS SEEN LAST NIGHT.

ALSO...THE TIMING OF THE PROGRESSION IS SLOWING DOWN AS WELL. THIS

SLOWING TREND IS QUITE IS MATCHED BY THE LATEST SATELLITE

OBSERVATIONS WITH INDICATED THE UPPER LOW CENTER DEEPENING AND

SWINGING A LITTLE MORE SOUTHERLY INTO ERN NEBRASKA. THE OBSERVED

SATELLITE TRENDS OVER THE LAST SEVERAL HOURS NICELY MATCH THE

EARLY PERIOD MODEL TRENDS...PARTICULARLY THE NAM12. SO...SINCE THE

MODELS ARE IN DECENT AGREEMENT FOR THE EARLY PORTIONS OF THE SHORT

TERM...HAVE GENERALLY FOLLOWED THE TRACK AND TIMING OF THE NAM.

WHAT THIS MEANS AS FAR AS THE MORNING FORECAST UPDATE IS

CONCERNED IS THAT THE PROGRESSION OF THE SYSTEM WILL BE A LITTLE

SLOWER...WITH PCPN NOT HITTING THE I-39 CORRIDOR UNTIL LATER THIS

MORNING AND THEN STEADILY OVERSPREADING THE REGION THROUGH THE

MORNING AND INTO THE EARLY AFTERNOON. THE BULK OF THE PCPN WILL

MOSTLY BE RAIN THROUGH THE DAY TODAY...WITH THE EXCEPTION OF THE

FAR WESTERN LOCATIONS WHICH WILL SEE SOMETHING OF A WINTRY MIX OF

RAIN AND FREEZING RAIN THIS MORNING...CHANGING OVER TO RAIN AND

SNOW THIS AFTERNOON AND THEN CHANGING OVER TO ALL SNOW THIS

EVENING. THE SNOW WILL BEGIN TO MOVE THROUGH THE FOX VALLEY AND

INTO THE CHICAGO METRO AREA DURING THE EARLY EVENING

HOURS...THOUGH THE NWRN INDIANA COUNTIES SHOULD STILL SEE RAIN

WELL INTO THE EVENING. FINALLY BY AROUND MIDNIGHT...THE RAIN WILL

MOVE EAST OF THE CWA...AND THE WINTRY PCPN WILL COVER THE WHOLE

CWA. ONE COMPLICATING FACTOR WITH THE PCPN TYPE FORECAST IS THE

AFFECT OF A PRONOUNCED MID LEVEL DRY SLOT ASSOCIATED WITH THE

SYSTEM. THE DRY SLOT IS ALREADY OBSERVED IN THE LATEST WATER VAPOR

IMAGERY...AND FOLLOWING THE TIMING OF THE NAM12 SOLUTION...THE DRY

SLOT WILL PUSH INTO THE WRN PORTIONS OF THE CWA BY MIDNIGHT. THE

EXACT LOCATION OF THE LOW CENTER IS CRITICAL TO THE PCPN FORECAST.

THE CURRENT EXPECTATION IS THAT A PERIOD OF FREEZING

DRIZZLE...PERHAPS MIXED WITH A LITTLE LIGHT SNOW...WILL CROSS THE

AREA LATE TONIGHT THROUGH SUNDAY MORNING. THE NRN TIER COUNTIES

ALONG THE WISCONSIN BORDER MAY REMAIN NORTH OF THE IMPACT OF THE

DRY SLOT...SEEING JUST THE CHANGE FROM RAIN TO SNOW AND MISS THE

FREEZING DRIZZLE. THE AREA SEEING THE MOST IMPACT OF THE FREEZING

DRIZZLE SHOULD BE ALONG AND SOUTH OF I-80...THOUGH LOCATIONS

BETWEEN I-80 AND I-88 WILL LIKELY SEE MORE OF A MIX OF LIGHT SNOW

AND FREEZING DRIZZLE.

FOLLOWING THE PASSAGE OF THE DRY SLOT...THE WRAP AROUND SNOW AND

PORTIONS OF A DEFORMATION ZONE SNOW BAND WILL SPREAD ACROSS THE

AREA. THIS IMPACT OF THE SNOW WILL BE COMPOUNDED BY STRONG

NORTHWEST WINDS AS SFC LOW CONTINUES A SLOW DEEPENING TREND AND

STRONG ARCTIC HIGH PRESSURE BUILDS INTO THE NRN PLAINS.

INITIALLY...SNOW-LIQUID RATIOS SHOULD BE IN A FAIRLY TYPICAL 10-12

TO 1 RANGE...BUT AS THE COLD AIR ASSOCIATED WITH THE ARCTIC AIR

MASS IS DRAWN OVER NRN IL...SNOW RATIOS WILL INCREASE TO 20 TO 1

OR GREATER...LEADING TO A LIGHT...DRY SNOW. WITH WINDS INCREASING

TO 40MPH OR HIGHER... BLOWING AND DRIFTING SNOW WILL BE A

SIGNIFICANT CONCERN AS WELL AS SERIOUS REDUCTIONS OF VISIBILITY.

DEPENDING ON THE EXACT STRENGTH OF THE WINDS AND LEVEL OF

VISIBILITY REDUCTION IN THE BLOWING SNOW...SOME AREAS MAY SEE

BLIZZARD CONDITIONS SUNDAY AFTERNOON AND EVENING.

ALSO BY SUNDAY EVENING...LAKE EFFECT SNOW WILL BECOME A SERIOUS

CONCERN FOR NWRN INDIANA. AN EXTENDED NWLY FETCH OF COLD AIR OVER

THE RELATIVELY WARM LAKE MICHIGAN WATERS WILL BE PRIMED FOR LAKE

EFFECT SNOWS. LAKE EFFECT SNOW AMOUNTS WILL VARY DEPENDING ON HOW

LAKE EFFECT SNOW BANDS SET UP...BUT GIVEN THE DURATION OF THE

FAVORED FETCH...PORTIONS OF PORTER COUNTY COULD SEE AMOUNTS IN

EXCESS OF 20 INCHES.

FINALLY...TEMPERATURES WILL BE A CONCERN. AS THE ARCTIC HIGH

PRESSURE BUILDS EWD...AIR TEMPERATURES SHOULD DROP BELOW ZERO FOR

LOCATIONS AWAY FROM LAKE MICHIGAN AND THE LAKE EFFECT SNOW REGION.

TEMPERATURES SHOULD REMAIN BITTERLY COLD WELL INTO MID WEEK. WHILE

THE STRONG WINDS ARE STILL IN PLACE MONDAY AND TUESDAY...THERE

WILL LIKELY BE PERIODS WHERE THE WIND CHILL READING WILL DROP

BELOW -20F.

KREIN

[KeenerWx]

You get Met to run the WRF for you. Would be pretty interesting to see what it shows. As Adam Samberg would say....ahh nevermind.

[KeenerWx]

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

429 AM CST SAT DEC 11 2010

DISCUSSION

345 AM...

ALSO BY SUNDAY EVENING...LAKE EFFECT SNOW WILL BECOME A SERIOUS

CONCERN FOR NWRN INDIANA. AN EXTENDED NWLY FETCH OF COLD AIR OVER

THE RELATIVELY WARM LAKE MICHIGAN WATERS WILL BE PRIMED FOR LAKE

EFFECT SNOWS. LAKE EFFECT SNOW AMOUNTS WILL VARY DEPENDING ON HOW

LAKE EFFECT SNOW BANDS SET UP...BUT GIVEN THE DURATION OF THE

FAVORED FETCH...PORTIONS OF PORTER COUNTY COULD SEE AMOUNTS IN

EXCESS OF 20 INCHES.

Oh boy...

[janetjanet998]

STL

THE SLOWER SOLUTIONS PRIMARILY COME INTO PLAY TONIGHT...WITH

ISTENTROPIC ANALYSIS INDICATING TROWAL DEVELOPING AS MOISTURE AND

PRECIP WRAPS BACK INTO THE COLD AIR AND RETURNS TO OUR FA. DONT

REALLY SEE ANY BANDING POTENTIAL...BUT CERTAINLY ISENTROPIC ASCENT

WILL BE STRONG ENOUGH TO GENERATE LIGHT...BUT STEADY SNOWFALL.

MODEL QPF DEPICTIONS LOOK QUITE REASONABLE...AND SUGGESTS 2-3

INCHES OF SNOW MAY FALL IN N SECTIONS OF THE FA LATE TONIGHT INTO

SUN MORNING...WITH PERHAPS UP TO AN INCH ALONG THE I-70 CORRIDOR.

BELIEVE MOST OF THE MEASURABLE PRECIP WILL EXIT OUR FAR E COUNTIES

AROUND MIDDAY SUNDAY.

[weatherbo]

You get Met to run the WRF for you. Would be pretty interesting to see what it shows. As Adam Samberg would say....ahh nevermind.

Did yestersay off of 12 z runs and that was pretty impressive alone, but with the southward shift overnight I'm gonna ask him to run another when he gets home form work, which isn't til noon.

[Cyrys]

As of the 4AM observations in Iowa, the lowest pressure was in Orange City at 1000.33. Orange City is about 40 miles south of the Minnesota/Iowa border. Will see what the 5 AM observations show.

[KeenerWx]

Did yestersay off of 12 z runs and that was pretty impressive alone, but with the southward shift overnight I'm gonna ask him to run another when he gets home form work, which isn't til noon.

I'll be waiting.

Be sure to post it!

[janetjanet998]

DSM

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE DES MOINES IA

449 AM CST SAT DEC 11 2010

SHORT TERM /TODAY AND TONIGHT/

CURRENTLY THE SFC LOW IS SET UP WELL SOUTH OF PREVIOUS PROJECTIONS.

THE 00Z GFS INITIALIZED SFC FEATURES AND THE PV ANOMALY LOCATIONS

WELL WHILE THE NAM WAS TOO FAR NORTH IN BOTH INSTANCES. BASICALLY

FOLLOWED A BLEND OF THE 03Z SREF AND THE 00Z GFS FOR SFC FEATURES

AND QPF.

[baroclinic_instability]

DSM

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE DES MOINES IA

449 AM CST SAT DEC 11 2010

SHORT TERM /TODAY AND TONIGHT/

CURRENTLY THE SFC LOW IS SET UP WELL SOUTH OF PREVIOUS PROJECTIONS.

THE 00Z GFS INITIALIZED SFC FEATURES AND THE PV ANOMALY LOCATIONS

WELL WHILE THE NAM WAS TOO FAR NORTH IN BOTH INSTANCES. BASICALLY

FOLLOWED A BLEND OF THE 03Z SREF AND THE 00Z GFS FOR SFC FEATURES

AND QPF.

This discussion makes no sense considering the surface low is still sitting over NW Iowa at 1000 hpa while the 0Z GFS takes the low across central Iowa. Also worth noting the deformation band is setting up farther NW than the models predict.

[janetjanet998]

As of the 4AM observations in Iowa, the lowest pressure was in Orange City at 1000.33. Orange City is about 40 miles south of the Minnesota/Iowa border. Will see what the 5 AM observations show.

CHEROKEE 999.33

[BowMeHunter]

I'll just lol @ mke's afd and leave it at that.

[baroclinic_instability]

DSM

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE DES MOINES IA

449 AM CST SAT DEC 11 2010

SHORT TERM /TODAY AND TONIGHT/

CURRENTLY THE SFC LOW IS SET UP WELL SOUTH OF PREVIOUS PROJECTIONS.

THE 00Z GFS INITIALIZED SFC FEATURES AND THE PV ANOMALY LOCATIONS

WELL WHILE THE NAM WAS TOO FAR NORTH IN BOTH INSTANCES. BASICALLY

FOLLOWED A BLEND OF THE 03Z SREF AND THE 00Z GFS FOR SFC FEATURES

AND QPF.

KCKP at 999.4 hpa in very NW Iowa. This discussion is worthless.

[Cyrys]

Looks like the winner for low pressure as of 5AM is Cherokee Iowa at 999.3. Cherokee is about 65 miles south of the Minnesota/Iowa border. The lowest pressure in Minnesota was 1002 in Jackson.

[janetjanet998]

This discussion makes no sense considering the surface low is still sitting over NW Iowa at 1000 hpa while the 0Z GFS takes the low across central Iowa. Also worth noting the deformation band is setting up farther NW than the models predict.

looks to me at 12z the low will be a hair south of the 06z NAM and north of 06z GFS, but a tad slower versus both? also a tad stronger

[baroclinic_instability]

looks to me at 12z the low will be a hair south of the 06z NAM and north of 06z GFS, but slower versus both? also a tad stronger

09Z surface analysis still deeper and farther NW than both. Also the PV anomaly is still tracking NE so no reason this surface low won't track a tad more E-NE before turning straight E. Also deformation band is farther NW than both GFS/NAM.

WV loop and PV anomaly. Circulation still heading north-east along the MN/IA/NE/SD border.

http://rap.ucar.edu/...e=-1&duration=4

[Cyrys]

Rochester, Austin, Preston, and Dodge Center(SE MN) all reporting mixed precip or freezing rain as of 5AM. Winona still reporting light snow while La Crosse is reporting Light Snow and mist. Points south of La Crosse in Wisconsin are reporting mixed precip or freezing rain. I might just luck out, as the dry punch never quite reached me in the southwest MSP metro.

[prinsburg_wx]

Am I right or not thus far?

http://www.hpc.ncep....rgnamsfcwbg.gif

kudos...great discussions & analysis, thank you