Feb. 19th-22nd Winter Storm Part 2

[baroclinic_instability]

All depends on where it enters the Plains. My hunch now is it comes into the plains farther to the north because of it being stronger which should equal more ridging ahead of it in the Plains.

I am not discounting it. RGEM is scary intense and sticking to its guns.

[baroclinic_instability]

Prinsburg where did your RGEM maps go?

[BowMeHunter]

To my defense, Bow told me that the EURO QPF inside 48 hours was one of the worst models so I went with it.

Last time I trust him

I read that in the SNE thread some time back. And you said the same to me after I told you that you knob gobbler.

[prinsburg_wx]

Prinsburg where did your RGEM maps go?

sorry...thought i posted the 12z runs but here's 18z 24 & 36

[baroclinic_instability]

Couldn't the early band of heavy snow be an inhibiting factor for the WAA?

Not really. A narrow corridor of early snow is not going to put a kabash on the WAA--especially aloft where it counts. Large snowpacks will put a kabash on WAA to a degree which will then influence it aloft as well--but the large expanses of bare ground here will only help.

[snowstormcanuck]

sorry...thought i posted the 12z runs but here's 18z 24 & 36

RGEM really shunting the precip SE as it moves east. That's a continuation of what it was doing at 12z, maybe even more so this run.

[baroclinic_instability]

sorry...thought i posted the 12z runs but here's 18z 24 & 36

Wow 985. Once 0Z rolls around--we will truly be getting into NOWcast time. Hopefully the guidance has an idea by then--but it probably will not.

[SpartyOn]

Mixing all the way to I69. Per the DTX AFD. Wow a small shift or cooler could change the game for us living on the edge of a significant snow or mixed bag

[kab2791]

GRR issuses Warnings everywhere with 1/4-1/3" ice around 94

[Harry]

I read that in the SNE thread some time back. And you said the same to me after I told you that you knob gobbler.

GRR has actually went with a warning already. Did not expect that..

[Harry]

RGEM really shunting the precip SE as it moves east. That's a continuation of what it was doing at 12z, maybe even more so this run.

Strange how it sends one low to S.MN and then has another just south of here.

Can't recall seeing that happen with this type of system.

[prinsburg_wx]

Wow 985. Once 0Z rolls around--we will truly be getting into NOWcast time. Hopefully the guidance has an idea by then--but it probably will not.

it has a L that drifts across n IA through 48...here's total 48hr qpf

[prinsburg_wx]

Strange how it sends one low to S.MN and then has another just south of here.

Can't recall seeing that happen with this type of system.

it's the rgem but i hope it's qpf forecast pans out...lol

[Harry]

it's the rgem but i hope it's qpf forecast pans out...lol

I hear you.

My *guess* is the MN Low gets weakened by the blocking upstream and thus forces it to redevelop farther to the se. Again don't recall seeing that happen before so take it fwiw.

[wisconsinwx]

One thing I am noticing the weather offices doing is prolonging the back end snow. Previously the Southern Wisconsin offices were expecting this mess to wind down by Monday morning. However, now it's looking likely at least a couple inches of snow will fall in SE Wisconsin even during the day Monday, only prolonging the storm impacts.

[Stevo6899]

RGEM really shunting the precip SE as it moves east. That's a continuation of what it was doing at 12z, maybe even more so this run.

Yea and I think the euro also did that, thus the more southerly precipitation. I think the Nam and gfs are pushing the precipitation too far north.

[Moneyman]

Fun times ahead it looks like. Another storm to track after this as well for the midwest.

[Natester]

Ice ice baby.

[daddylonglegs]

19.12Z MODELS LOOK TO HAVE INITIALIZED RATHER WELL AND CONTINUE TO

OFFER A RATHER TIGHT CONSENSUS OF SOLUTIONS FOR THE IMPENDING WINTER

STORM TO IMPACT THE REGION TONIGHT THRU MON. GFS DID LOOK TO

INITIALIZE SFC DEW POINTS IN THE MOISTURE COMING NORTH ACROSS EAST

TX/OK SOME 5F TO 10F TOO HIGH. THIS LIKELY WHY ITS PRECIP TOTALS FOR

THE AREA LATE TONIGHT THRU MON ARE AMONG THE HIGHEST. DPROG/DT OF

500MB HGTS AT 19.12Z SHOWED MODEL RUNS OF 17.12Z AND 18.12Z ALL

VERIFIED QUITE WELL...WITH THE TIGHTER CONSENSUS FAVORING A

COMPROMISE OF THE EARLIER RUNS. THRU 36HRS...MODELS HAVE TRENDED A

BIT STRONGER WITH THE SHORTWAVE ENERGY INTO IA BY 00Z MON AND A BIT

STRONGER/SLOWER WITH THE DEVELOPING 500MB LOW OVER NEB/SD. GFS WITH

SOMEWHAT BETTER RUN-TO-RUN CONSISTENCY AT 00Z MON. BETTER MODEL

SIMILARITY SEEN THRU MON/MON NIGHT AS THE MID LEVEL LOW/TROUGH MOVES

EAST ACROSS THE REGION...WITH A TREND TOWARD STRONGER AND FAVORING

FASTER OF THE EARLIER RUNS. BY TUE/TUE NIGHT...TREND IS FASTER AS

THE TROUGH EXITS OFF THE EAST COAST...BUT GOOD BETWEEN MODEL AND

RUN-TO-RUN CONSISTENCY WITH THE NEXT TROUGHING/ENERGY INTO THE

WESTERN CONUS. CHECK OF OBS VS. MODEL DATA AT 18Z SHOWED MODELS

GENERALLY GOOD WITH THE SFC MASS FIELDS OVER THE CENTRAL CONUS...

THOUGH GFS REMAINED SOME 5F TO 10F TOO HIGH WITH SFC DEW POINTS IN

THE MOISTURE RETURN ACROSS KS/OK. PER WV IMAGERY...NAM/ECMWF/GEM

LOOKED A BIT BETTER WITH THE WEST COAST/WESTERN CONUS SHORTWAVE

DETAILS. NO CLEAR MODEL FAVORITE THIS CYCLE...BUT SOME INDICATIONS

TO BE WARY OF THE GFS. EVEN WITH THE IMPENDING MAJOR WINTER STORM...

FAVORING ONE MODEL OVER THE OTHER LOOKS TO HAVE MINIMAL IMPACT ON

THE SENSIBLE WEATHER OUTCOME TONIGHT INTO MON. FAVORED THE MODEL/

ENSEMBLE CONSENSUS ONCE AGAIN...WITH SHORT TERM FCST CONFIDENCE

QUITE GOOD THIS CYCLE.

FOR THE SHORT TERM...NOT MUCH CHANGE IN FCST THINKING FOR THE MAJOR

WINTER STORM TO IMPACT THE REGION STARTING LATER TONIGHT AND

CONTINUING INTO MONDAY. MODELS ALL CONTINUE TO INDICATE VERY

IMPRESSIVE 925-700MB THERMO-DYNAMIC/FN CONVERGENCE FORCING/LIFT TO

MOVE IN TONIGHT AND ACROSS THE AREA SUN. THIS ALONG WITH STRONG

MOISTURE TRANSPORT OF AN AIRMASS WITH 200-250 PERCENT OF NORMAL

PW...STRONG PV ADVECTION AHEAD OF THE SHORTWAVE AND MDT/STRONG

DIVERGENCE ALOFT BETWEEN COUPLED 300-250MB JET MAXES. PRECIP

EXPECTED TO DEVELOP/EXPAND VERY QUICKLY ACROSS THE REGION LATER

TONIGHT AS THE MOISTURE ARRIVES. MODELS AND SREF PROBABILITIES

INDICATE POTENTIAL FOR AS MUCH AS 50 TO 100 J/KG OF CAPE IN THE WARM

SECTOR/INFLOW AIRMASS LATE TONIGHT/SUN. WITH THE STRONG FORCING/LIFT

AND POSSIBLE CAPE...ADDED MENTION OF ISOLATED THUNDER TO THESE

PERIODS FOR MUCH OF THE FCST AREA. IF CONVECTION/THUNDER OCCURS WITH

SNOW...BURSTS OF VERY HEAVY SNOW WITH SNOWFALL RATES OF 2 TO 3

INCHES/HR POSSIBLE. THIS COULD QUICKLY RAISE HAVOC WITH EXPECTED

STORM TOTAL SNOWFALLS IF THE CONVECTION ANCHORS IN THE STRONG FN

CONVERGENCE BAND FOR ANY LENGTH OF TIME. MODEL CONSENSUS STILL KEEPS

THE 0C 850MB ISOTHERM VERY NEAR AN AUSTIN TO WI DELLS LINE SUN. BULK

OF PRECIP NORTH OF ROUGHLY I-90 EXPECTED TO BE SNOW WITH PERHAPS

SOME SLEET AT TIMES SOUTH OF A KRST-KONA-KVOK LINE. A MIX OF WINTRY

PRECIP TYPES EXPECTED SOUTH OF THE AUSTIN TO WI DELLS LINE...AS

MAXIMUM TEMPS ALOFT RANGE FROM NEAR 0C TO +5C TO +6C CLOSER TO

OELWEIN AND DUBUQUE. PRECIP IN THESE AREAS TO START OUT AS A PERIOD

OF SNOW/SLEET TONIGHT...CHANGING TO FREEZING RAIN LATER TONIGHT/SUN

MORNING...THEN TO RAIN SUN AS BOUNDARY LAYER TEMPS ACROSS MUCH OF

NORTHEAST IA/SOUTHWEST WI WARM INTO THE THE MID/UPPER 30S. FCST

GRIDS FOR PRECIP TYPES TONIGHT/SUN BASED ON THE LOCATION OF THE 0C

850MB ISOTHERM BEING CORRECT. ANY DEVIATION IN THE EXPECTED 925-

850MB THERMAL PROFILE WILL HAVE AN IMPACT ON LOCATION OF PRECIP

TYPES/SNOW AMOUNTS...ESPECIALLY NEAR A KAUM-KLSE-MAUSTON LINE.

DYNAMIC COOLING WITH THE STRONG LIFT AND OCCLUSION OF THE SFC-850MB

LOW COOLS THE COLUMN VERY QUICKLY SUN EVENING...WITH THE MIXED

PRECIP TYPES ACROSS THE SOUTH HALF OF THE FCST AREA CHANGING QUICKLY

BACK TO SNOW. THE STRONGER MID LEVEL TROUGH REMAINING WEST OF THE

AREA SUN NIGHT INTO MON AND A SFC-700MB TROUGH REMAINING OVER THE

AREA PROVIDE CONTINUED FORCING/LIFT FOR SNOW INTO MON MORNING.

RAISED SNOW CHANCES TO 80-100 PERCENT SUN NIGHT AND 60-70 PERCENT

MON MORNING WITH ACCUMULATIONS NOW EXPECTED THRU MON MORNING. ONE

CONCERN ALREADY IS POTENTIAL NEED TO EXTEND WINTER STORM WARNING TO

AT LEAST NOON MON. PLENTY OF TIME TO DEAL WITH THAT IF NEEDED WITH

WINTER STORM WARNING WELL LAID OUT FOR NOW. DEEP...FRESH SNOW COVER

AND CAN/ARCTIC HIGH BUILDING LOOK TO SEND TEMPS TO NEAR/BELOW ZERO

FOR TUE MORNING. A COLDER PERIOD TUE/TUE NIGHT WITH THIS HIGH

OVER/DRIFTING EAST OF THE AREA.

[kab2791]

it's the rgem but i hope it's qpf forecast pans out...lol

Whatever gives you the most no matter how it gets the point A to B Says to the NAM, "what dryslot?"

[snowstormcanuck]

Yea and I think the euro also did that, thus the more southerly precipitation. I think the Nam and gfs are pushing the precipitation too far north.

Thing is, at least initially, the RGEM is as far north, if not further north than the GFS/NAM. But rather than progress the low e-w it kind of deepens/stalls it in southern MN, which in turn increases the downstream confluence, causing a lot of my snow to dry up. I don't think the EURO does that at all. In fact, IIRC correctly, the 12z EURO had one of the weakest lows of any of the models. Exact opposite of the RGEM, even if the sensible wx solutions are similar.

[Thundersnow12]

very cool 6hr sequence from a forecast sounding perspective for here tomorrow morning from 9z to 15z. We saturate rapidly after 9z and can really see the 850mb-950mb layer cool quickly as well due to the amount of ascent taking place and destabilization through the column and look to have a brief period of some intense snow around 12z. After that we get quite the warm push at 15z and some pretty pornographic wind fields as well lol

[baroclinic_instability]

Ice ice baby.

Your avatar is wicked. When was that event? Only time you see large supercells clustered like that is during bombing events where the upper low tanks out and supercells start popping off everywhere as the height fields tank and rapidly destabilize near the low.

[prinsburg_wx]

the rgem has the 850 L near sioux falls at hr 30 so could be some mix for a time in s MN...is this the time period for possible thundersnow, baro?

[baroclinic_instability]

Thing is, at least initially, the RGEM is as far north, if not further north than the GFS/NAM. But rather than progress the low e-w it kind of deepens/stalls it in southern MN, which in turn increases the downstream confluence, causing a lot of my snow to dry up. I don't think the EURO does that at all. In fact, IIRC correctly, the 12z EURO had one of the weakest lows of any of the models. Exact opposite of the RGEM, even if the sensible wx solutions are similar.

Euro verbatim is not too realistic IMO with its track. It has had more significant issues than usual with this storm and has typically been the most suppressed and last to trend away from that with this storm.

[Thundersnow12]

Your avatar is wicked. When was that event? Only time you see large supercells clustered like that is during bombing events where the upper low tanks out and supercells start popping off everywhere as the height fields tank and rapidly destabilize near the low.

I'm pretty sure that pic is from 5/10 last year lol I saved it as well. what a fun and intense nowcasting day that was.

[baroclinic_instability]

Harry what do the euro ensemble members look like compared to its op?

[Thundersnow12]

looks like LOT is going to put the next row of counties under a WWA and thunderstorm talk in the warm sector ahhh TSSN to elevated storms would be the best lol

SHORT TERM...WINTRY WEATHER MIX FOR THE WEEKEND CONTINUES TO BE MAIN

CONCERN FOR THE LATEST FORECAST PACKAGE. A WARM FRONT LIFTING

THROUGH THE REGION WILL BRING SNOW...SLEET...AND FREEZING RAIN

TONIGHT INTO SUNDAY MORNING BEFORE BECOMING ALL RAIN BY SUNDAY

AFTERNOON. SPRINKLE IN A FEW THUNDERSTORMS SUNDAY EVENING...THEN

RETURN TO SNOW OVERNIGHT SUNDAY AS THE WEATHER SYSTEM DEPARTS TO

THE EAST.

A BROAD TROUGH OVER THE WESTERN CONUS WILL SLOWLY PROGRESS EASTWARD.

A POTENT SHORTWAVE TROUGH WILL KICK OUT OVER THE ROCKY MOUNTAINS

LATER THIS EVENING WITH SURFACE CYCLOGENESIS OCCURRING OVERNIGHT.

STRONG AREA OF FRONTOGENESIS AS WELL AS ISENTROPIC LIFT PROVIDE MAIN

FORCING OVERNIGHT ACROSS THE FORECAST AREA. MODEL SOUNDINGS BECOME

SATURATED SHORTLY AFTER MIDNIGHT ALLOWING ONSET OF PRECIPITATION

FROM WEST TO EAST ACROSS THE FORECAST AREA. WET

PRECIPITATION LOOKS LIKE IT WILL INITIALLY START OUT AS SNOW AS THE

COLUMN COOLS BELOW FREEZING DUE TO EVAPORATION IN THE TOP-DOWN

SATURATION PROCESS. TWO OR THREE INCHES OF SNOW IS POSSIBLE

ACROSS THE NORTHWESTERN PORTIONS OF THE FORECAST AREA. WARM LAYER

ALOFT QUICKLY DEVELOPS HOWEVER AT WHICH POINT WE COULD START TO

MIX IN SLEET. BY AROUND DAYBREAK TOMORROW...THE WARM LAYER IS

SUFFICIENTLY DEEP TO COMPLETELY MELT ANY FROZEN PRECIP. SURFACE

TEMPERATURES WILL STILL BE BELOW ZERO ACROSS ROUGHLY THE NORTHERN

HALF OF THE FORECAST AREA INDICATING FREEZING RAIN. BY THIS

POINT...FORCING IS STRONGEST ALONG AND JUST NORTH OF THE WISCONSIN

AND ILLINOIS BORDER. WILL GO AHEAD AND UPGRADE THE WINTER STORM

WATCH TO A WARNING AS THERE IS INCREASING CONFIDENCE ON

SIGNIFICANT ACCUMULATION OF ICE IN EXCESS OF A QUARTER INCH. WITH

THE THICKNESS PACKING PRETTY TIGHT AND A FAIRLY QUICK TRANSITION

NORTHWARD OF THE WARM FRONT...DONT THINK THERE WILL BE A PROLONGED

PERIOD OF FREEZING RAIN ALONG THE SECOND TIER OF COUNTIES...BUT

SUFFICIENTLY LONG ENOUGH THAT THERE MAY BE LIGHT ACCUMULATIONS ON

ROADWAYS THAT WILL CAUSE PROBLEMS...THUS WILL GO AHEAD AND ISSUE A

SHORTER TERM WINTER WEATHER ADVISORY FOR THIS AREA.

AT SOME POINT...TEMPERATURES WILL WARM ENOUGH THAT PRECIPITATION

WILL BECOME ALL RAIN. STILL A LITTLE UNCERTAINTY AT WHICH POINT THIS

WILL OCCUR...BUT WITH STRONG WARM ADVECTION WITH A 60KT

SOUTHWESTERLY JET AT 700MB...THERMAL PACKING WILL BECOME TIGHT

THROUGH THE AFTERNOON SLIMMING THE MIXED PRECIP AREA. FOR

NOW...EXPECT THIS TRANSITION FOR THE NORTHERN TIER COUNTIES TO

HAPPEN AROUND NOON TOMORROW. STRONGEST FORCING SUNDAY AFTERNOON

TRANSITIONS NORTH OF THE STATE LINE. EXPECT LIGHT RAIN EVEN DRIZZLE

AS YOU MOVE FARTHER SOUTH AWAY FROM THE WARM FRONT. A MARGINAL

INSTABILITY AXIS PASSES THROUGH THE REGION LATE AFTERNOON INTO THE

EVENING AND WE MAY SEE A FEW THUNDERSTORMS DEVELOP AHEAD OF THE

SURFACE LOW. THIS LOW IS PROGGED TO PASS THROUGH THE FORECAST AREA

AFTER MIDNIGHT TOMORROW WITH TEMPERATURES QUICKLY DROPPING ON THE

BACKSIDE OF THE LOW AND PRECIP TRANSITIONING BACK TO ALL SNOW. COULD

SEE SOME LIGHT ACCUMULATIONS DURING THE DAY MONDAY BEFORE THE

TRAILING 700MB TROUGH FINALLY PASSES THROUGH LATE MONDAY NIGHT

SIGNALING AN END TO THE PRECIPITATION.

[TugHillMatt]

GRR has actually went with a warning already. Did not expect that..

Yeah, did you read the warning details? Yet another Warning from GRR that does not match what they discuss in their forecast discussion.

[Stevo6899]

Thing is, at least initially, the RGEM is as far north, if not further north than the GFS/NAM. But rather than progress the low e-w it kind of deepens/stalls it in southern MN, which in turn increases the downstream confluence, causing a lot of my snow to dry up. I don't think the EURO does that at all. In fact, IIRC correctly, the 12z EURO had one of the weakest lows of any of the models. Exact opposite of the RGEM, even if the sensible wx solutions are similar.

Good points, thanks.. I'm on my phone so only glanced at ewall euro. Weird to see the euro on its own. Don't think it was just a bad run because last night it had all snow in the Detroit area also. I do think its too supressed. So many models, which one will score?