12z Model Suite Discussion Thread Jan. 2nd / 3rd

[bluewave]

thanks....what a disaster

 

We'll just have to hope that the coastal trough snows don't shift within the last 48 hrs or so. Getting the trough axis

right this far out in time can be very tricky.

[LnbWx]

I know we're discussing the snow threat but how are we looking for the single digit lows on Friday?

 

GFS/Euro 3 runs before were showing surface -10 line just above NYC. How are they looking now? Assuming it was because of the snow pack expected to be there, are we seeing any changes in the temperatures?

 

Thanks.

[TWCCraig]

I know we're discussing the snow threat but how are we looking for the single digit lows on Friday?

 

GFS/Euro 3 runs before were showing surface -10 line just above NYC. How are they looking now? Assuming it was because of the snow pack expected to be there, are we seeing any changes in the temperatures?

 

Thanks.

 

Much warmer. Both Euro and GFS keep 0F line just NW of NYC. Euro shockingly has temps down to -26F on the CT coast line. Overdone.

[MJO812]

GFS still shows single digits for the area on Saturday morning

[LnbWx]

Much warmer. Both Euro and GFS keep 0F line just NW of NYC. Euro shockingly has temps down to -26F on the CT coast line. Overdone.

 

 

GFS still shows single digits for the area on Saturday morning

 

Thanks. I'm more excited about the cold than the snow.

 

Also, not sure this is a banter and should be kept off the thread.

[NEG NAO]

Just posted by Paul Kocin at HPC :

 

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1058 AM EST TUE DEC 31 2013

VALID 12Z FRI JAN 03 2014 - 12Z TUE JAN 07 2014

A VERY WINTRY SCENARIO IN THE EAST STARTS OFF THE MEDIUM RANGE
FORECAST WITH A QUICK WARM UP IN THE CENTER OF THE COUNTRY. THE
WARM UP IS SHORT LIVED AS A NEW AND SIGNIFICANT OUTBREAK OF COLDER
AIR BEGINS TO ENTER THE NORTHERN ROCKIES AND PLAINS BY DAY
4/SATURDAY AND PROGRESSES EASTWARD BY SUNDAY DAY 5. WITH LARGE
UNCERTAIN IT STILL APPEARS THAT SOME FORM OF PRECIPITATION EVENT
WILL FORM IN ASSOCIATION WITH THIS NEXT OUTBREAK OF COLD AIR ON
DAY 5 INTO DAY 6/MONDAY...WITH A HUGE RANGE OF SOLUTIONS FROM A
FRONTAL PASSAGE TO A MAJOR CYCLONE. BY DAY 7/TUESDAY...MUCH OF
THE CENTRAL AND EASTERN US IS UNDER THE INFLUENCE OF BELOW TO MUCH
BELOW NORMAL TEMPERATURES.

A CUTOFF UPPER RIDGE OVER GREENLAND/NORTHEAST CANADA WILL HELP
RETAIN AN UPPER LOW OVER SOUTHEASTERN CANADA THAT CONTINUES TO
FORCE A TROUGH MOVING TOWARD THE EASTERN US TO REMAIN ON A PATH
CONDUCIVE TO SNOW OVER PORTIONS OF THE NORTHEAST US ON DAY 3.
WHILE THE DETAILS OF THE TROUGH EVOLUTION SEEM FAIRLY
STRAIGHTFORWARD DURING THE BEGINNING OF THE MEDIUM RANGE PERIOD
FOR THE ENSEMBLE MEANS AND THE EVOLUTION OF A COLD CANADIAN HIGH
BUILDING EASTWARD ACROSS SOUTHEASTERN CANADA ARE ALSO
STRAIGHTFORWARD...THE DETAILS OF THE ACTUAL TROUGH EVOLUTION AND
RESULTING SURFACE BAROCLINIC STRUCTURE REMAINS COMPLEX.
SIGNIFICANT MODEL SPREAD DUE TO THE LIKELIHOOD OF SEVERAL CENTERS
OF LOW PRESSURE OF VARYING STRENGTH COMING TOGETHER TO EVENTUALLY
FORM A CYCLONE OVER THE WESTERN ATLANTIC CONTINUES TO MAKE THIS A
CHALLENGING FORECAST EVEN AT THE START OF THE MEDIUM RANGE. IN
GENERAL...CONTINUITY FROM THE OVERNIGHT FORECAST IS MAINTAINED
BASED ON THE CONSISTENCY OF THE ECMWF ENSEMBLE MEANS WITH INPUT
FROM THE 00Z ECMWF AND 06Z GFS...BOTH OF WHICH MAINTAIN A SIMILAR
SPEED AND AMPLITUDE OF THE TROUGH NEARING THE EAST COAST. WITH THE
MAIN TROUGH NEARING THE EAST COAST BY FRIDAY MORNING...A MULTIPLE
CENTER SURFACE SYSTEM IS STILL EXPECTED WITH THE REMAINING
QUESTION BEING HOW INTENSE THE WESTERNMOST SURFACE LOW RESPONDS TO
THE UPPER LEVEL TROUGH WHILE OTHER SURFACE CENTER OR CENTERS SCOOT
FARTHER EASTWARD. IN ANY EVENT...WHATEVER SNOW IS FALLING ON
FRIDAY MORNING SHOULD BE MOVING EASTWARD OUT TO SEA DURING THE DAY
AS THE SYSTEM CONTINUES EASTWARD.

WITH A MEAN UPPER RIDGE TRENDING TO BUILD OVER THE EASTERN PACIFIC
FROM THE SHORT RANGE INTO THE MEDIUM RANGE...SEVERAL SHORTWAVE
SYSTEMS WILL BEGIN TO PROGRESS SOUTH AND EASTWARD OVER WESTERN
CANADA WHILE ANOTHER LARGE UPPER LOW OVER NW CANADA ALSO BEGINS TO
MOVE SOUTH AND EASTWARD AS WELL. BY DAY 5...ANOTHER LARGE VORTEX
WILL BE FOUND ACROSS SOUTH CENTRAL CANADA WITH A HUGE MASS OF
ARCTIC AIR POISED TO MOVE SOUTH AND EASTWARD ACROSS MUCH OF THE
CENTRAL AND EASTERN US. SIGNIFICANT DIFFERENCES ALSO CHARACTERIZE
THIS DEVELOPMENT WITH THE ECMWF ENSEMBLE MEANS SHOWING THE LARGEST
AMPLITUDE AND GREATER SOUTHWARD PUSH OF THE ARCTIC AIR WITH
GFS/NAEFS ENSEMBLE MEANS SHOWING A SLIGHTLY FLATTER
SCENARIO...ESPECIALLY BY DAY 6. WHILE THE 00Z ECMWF CREATES A
POTENTIALLY HISTORIC SCENARIO BY DAY 6...IT REMAINS A VERY LOW
PROBABILITY SOLUTION AS IT REMAINS MUCH MORE AMPLIFIED THAN THE
CORRESPONDING ECMWF ENSEMBLE MEAN SOLUTION. THE 06Z GFS ACTUALLY
LOOKS MORE LIKE THE 00Z ECMWF ENSEMBLE MEAN SOLUTION AND IS
SOMEWHAT FOLLOWED WHILE STILL SHOWING A VERY LARGE COLD OUTBREAK
MOVING INTO THE CENTRAL AND EASTERN US ON DAYS 6 INTO 7...WITH THE
DETAILS OF HOW LOW PRESSURE AT THE SURFACE ULTIMATELY DEVELOPING
ALONG THE LEADING EDGE OF THE COLD AIR STILL VERY MUCH UNCERTAIN
AT THIS POINT WITH A VERY MODEST SYSTEM SHOWN AT THE PRESENT TIME
BUT WILL LIKELY CHANGE SIGNIFICANTLY AS THE DAYS GET CLOSER.
CHANCES ARE THAT THIS NEXT SYSTEM WILL LIKELY ALSO BE A
SIGNIFICANT WINTER WEATHER EVENT SOMEWHERE FROM THE TENNESSEE AND
OHIO VALLEYS EASTWARD INTO THE NORTHEAST.

KOCIN
 

[ace0927]

We'll just have to hope that the coastal trough snows don't shift within the last 48 hrs or so. Getting the trough axis

right this far out in time can be very tricky.

 

the 12Z NAVGEM is essentially a complete miss

 

Edit: so is the GGEM

[allgame830]

the 12Z NAVGEM is essentially a complete miss

 

I am sure the forecast won't be based on the NAVGEM... lol

[donsutherland1]

I know we're discussing the snow threat but how are we looking for the single digit lows on Friday?

 

GFS/Euro 3 runs before were showing surface -10 line just above NYC. How are they looking now? Assuming it was because of the snow pack expected to be there, are we seeing any changes in the temperatures?

 

Thanks.

The GFS still indicates single digit readings across the region.

[wolfie09]

12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT

RANGE FORECASTS.

TROUGH MOVING THROUGH THE EAST

LOW MOVING THROUGH THE SOUTHEAST

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PREFERENCE: GFS/ECMWF/UKMET COMPROMISE

CONFIDENCE: AVERAGE

WHILE ITS SOLUTION ALOFT DOES NOT APPEAR TO STRAY FAR FROM THE

OTHER GUIDANCE, THE 12Z NAM SURFACE LOW SOLUTION ACROSS THE

EAST/NORTHWEST ATLANTIC LIES NORTH OF THE 00Z GLOBAL ENSEMBLE

ENVELOPE OF SOLUTIONS, AND WAS NOT CONSIDERED PLAUSIBLE. THE 00Z

CANADIAN OUTRACES THE REMAINDER OF THE GUIDANCE WITH THIS SYSTEM.

THE 00Z ECMWF/06Z GEFS MEAN SOLUTIONS FAVOR A COMPROMISE OF THE

00Z ECMWF/12Z GFS/00Z UKMET, WHICH IS PREFERRED WITH AVERAGE

CONFIDENCE CONSIDERING THE SYSTEM'S PROGRESSIVE NATURE

[ace0927]

I am sure the forecast won't be based on the NAVGEM... lol

ah, so its ONLY allowed to get a mention when it shows 24mm's of precip?

[SnowGoose69]

the 12Z NAVGEM is essentially a complete miss

 

Edit: so is the GGEM

 

Ordinarily that depiction by the NavGEM would thrill me because given its progressive bias its not THAT BAD...however, given where it was just 24-36 hours ago its gone way progressive, but perhaps its just back to being irself.

[allgame830]

ah, so its ONLY allowed to get a mention when it shows 24mm's of precip?

 

thats not what i am saying... but I would love to see the NWS or HPC use it haha definitely not

[jm1220]

ah, so its ONLY allowed to get a mention when it shows 24mm's of precip?

The NAVGEM's verification scores are poor, this was shown here even when it was depicting a blizzard.

[Allsnow]

Gfs ens mean is similar to op. Extends .5+ to the eastern half of nj

[ace0927]

The NAVGEM's verification scores are poor, this was shown here even when it was depicting a blizzard.

I know...my bringing it up was tongue in cheek...same with the GGEM.

[jm1220]

Gfs ens mean is similar to op. Extends .5+ to the eastern half of nj

That's a good sign. 0z worried me last night but hopefully today we see more of an extension back to the coast with the low which develops in response to the main trough rather than the lead vort. I would think there's more of a reflection near the coast, since models sometimes go too crazy on these lead vorts. The GFS might still be having feedback issues-notice the diamond shaped blob of convection it fires up as the lead vort develops that low. Usually that doesn't happen. For now I'd go with 3-6" or 4-8" for most of the area, higher amounts further east toward Long Island and north into CT.

[earthlight]

These look light years better then I thought they would

 

[+SNfreak21]

These look light years better then I thought they would

 

Ensemble #5 

[JSantanaNYC]

These look light years better then I thought they would

 

 

I wished you were the only person doing model analysis here.

You always give good info, even if the model shows nothing, you explain why is right or wrong.

[peregrinator]

These look light years better then I thought they would

 

 

 

Better than 00z, but not quite as good as 06z, where 5 or 6 of the 12 members actually dumped 0.75"+ from NYC eastward. Interestingly, it looks like the driest solutions have gotten drier since 00z, while the wetter solutions have trended even wetter--not something you'd expect as the event draws closer.

[REDMK6GLI]

Earthlight and allsnow do the PbP for the 12z euro please JSantanaNYC is right, you always explain model runs whether they're right or wrong

[WE GOT HIM]

A wetter sloution still cant be ruled out

These look light years better then I thought they would

 

[TauntonBlizzard2013]

Huge euro run. Should have a better idea of all the players involved

[Monmouth_County_Jacpot]

Earthlight and allsnow do the PbP for the 12z euro please JSantanaNYC is right, you always explain model runs whether they're right or wrong

I agree

[SnoSki14]

Come on Euro, just give a couple of inches and everyone will be happy.

[earthlight]

Come on Euro, just give a couple of inches and everyone will be happy.

 

If we beg in this thread, maybe it'll happen.

[earthlight]

Negligible changes so far. 

[REDMK6GLI]

Huge euro run. Should have a better idea of all the players involved

I think even earthlight knows that these model runs from the euro on are really going to be telling in what is going to happen with this storm

[mob1]

If we beg in this thread, maybe it'll happen.

Statistics show that begging is as useful as wishcasting.