Christmas Eve Potential Major Winter Storm

[gosaints]

Which is plausible. Need to wait for some sampling of the two streams.

absolutely could happen but the problem I am seeing is the northern stream is becoming stronger by the run

[gosaints]

Parallel GFS spaces the 2 systems enough to cut the 2nd one hard

[bud2380]

parallel still showing the larger snowstorm on the day after Xmas into the plains; moving into the midwest thru 192 hours

[bud2380]

http://i.imgur.com/KfEsC5E.png

[tim the weatherman]

was just looking at twc that they are saying that the begining of next week that rain for lower greatlakes and by xmas eve snow is in the forecast and by the way of this storm needs to get it's act together.

[bud2380]

wider view of the PGFS

 

http://weather.graphics/gsm/2014121812/central/gfs_6hr_snow_acc_central_38.png

[Money]

Most of that comes with a dif. storm though I'm pretty sure.

[bud2380]

GGEM a little more robust and the storm has it's act together more than what the GFS is showing. 

[bud2380]

Most of that comes with a dif. storm though I'm pretty sure.

It is, it's the day after Christmas into the weekend, probably should go on the other thread, but I posted it anyway.  That is the real storm I think worth watching for widespread snows. 

[Money]

GGEM looks to turn a lot of the rain into snow in WI. Tom, could you post the snowfall maps for ggem when you have the time? Thanks

[Money]

http://www.tropicaltidbits.com/analysis/models/gem/2014121812/gem_mslp_pcpn_frzn_us_22.png

 

http://www.tropicaltidbits.com/analysis/models/gem/2014121812/gem_mslp_pcpn_frzn_us_23.png

 

http://www.tropicaltidbits.com/analysis/models/gem/2014121812/gem_mslp_pcpn_frzn_us_24.png

 

http://www.tropicaltidbits.com/analysis/models/gem/2014121812/gem_mslp_pcpn_frzn_us_25.png

[CentralNebWeather]

Boy I love the look of this map. Nebraska gets drilled.  Almost want time to speed up so it doesn't disappear in future runs like has been the case so often this year.

[Tom]

12z GGEM seems to have the southern piece take control and this would be a great solution.  Just need it to phase a bit quicker.

[bud2380]

Money, here is the GGEM thru 6pm Xmas Eve

 

http://i.imgur.com/wdHTh3V.png

[tim the weatherman]

the way of things that this does not be a big snowstorm the way henry margusity of accuweather has said.

[Money]

ECMWF HR 120 has a 996 L in N. IL (the northern stream system) 

[Money]

How does it look, Tom?

[gosaints]

swing and a miss

[Tom]

12z Euro...it develops the stronger southern stream near FL/GA that rides up the East Coast this run.

[gosaints]

Clipper is colder thats about the only positive out of that run

[Money]

Clipper is colder thats about the only positive out of that run

 

I think we're in a good spot for at least a couple inches. Clipper should at least make everything white for Christmas. 

[tbone8]

.LONG TERM...(FRIDAY THROUGH WEDNESDAY)
ISSUED AT 358 AM EST THU DEC 18 2014

MOST IMPORTANT INFORMATION FIRST SO THIS LONG TERM WILL BEGIN WITH
DISCUSSION OF POSSIBLE WINTER STORM NEXT WEEK. HYPE ALREADY WELL
UNDERWAY BUT A LOT OF UNCERTAINTY REMAINS WITH RESPECT TO THE VERY
IMPORTANT AND CRITICAL DETAILS OF WHEN AND WHERE THIS STORM WILL
CREATE IMPACTS. CAUTIOUS BUT INFORMATIVE APPROACH WARRANTED GIVEN
THE DAY 6 TO 7 TIME FRAME AND A VERY ENERGETIC PACIFIC JET STREAM
WHICH IS POORLY SAMPLED. THUS NUMEROUS CRITICAL CHANGES AND
DEVIATIONS IN MODEL SOLUTIONS EXPECTED WITH EACH ITERATION OVER THE
NEXT SEVERAL DAYS. THE BROAD SYNOPTIC AGREEMENT AMONG MODELS DOES
GIVE HIGHER THAN NORMAL CONFIDENCE THAT A SUBSTANTIAL STORM SYSTEM WILL
IMPACT SOME PART OF THE EASTERN CONUS REGION BY CHRISTMAS.
HOWEVER...ALREADY SEEING MODEL ADJUSTMENTS IN POTENTIAL TIMING AND
TRACK OF SYSTEM AS WELL AS HOW FAST COLDER AIR WILL SWEEP IN.
CONFIDENCE REMAINS BELOW NORMAL ON IMPORTANT DETAILS SUCH AS
TRACK...PCPN TYPE AND AMOUNTS. LATEST 00Z MODELS TRENDING SYSTEM
WESTWARD AS THEY TEND TO DO WITH DYNAMICALLY STRONG AND NEGATIVELY
TILTED SYSTEMS. CURRENT MODEL RUNS DO BRING COLD AIR IN ON CHRISTMAS
EVE SO KEPT PCPN TYPE ALL SNOW IN THIS PERIOD FOR NOW. MODELS STILL
SHOWING A VERY STRONG LOW DEVELOPING WITH TIGHT GRADIENT AS BLOCKY
PATTERN STALLS SYSTEM OVER GREAT LAKES REGION. ANY SNOW THAT DOES
FALL BY CHRISTMAS WILL CERTAINLY CREATE TRAVEL ISSUES AND HAVE
SIGNIFICANT IMPACTS DUE TO BLOWING AND DRIFTING. THIS REMAINS WORTHY
OF MENTION IN HWO BUT RESTRAINT SHOULD BE EXERCISED FOR NOW IN THE
FORECASTS OF TRACK AND SNOW AMOUNTS GIVEN LITTLE SKILL AT THIS TIME
RANGE.

[Tom]

Right now the models are primarily getting their data from planes flying in the Pacific anyway.  Until this energy can get decent sampling (Sun/Mon), we should expect models to be inconsistent.

[Money]

18z GFS coming in with a  stronger/south/slower northern stream and a stronger southern stream. Let's see where this ends up..

[gosaints]

18z GFS coming in with a stronger/south/slower northern stream and a stronger southern stream. Let's see where this ends up..

Another whole new idea

[Money]

18z PAR

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014121818/gfsp_z500_mslp_us_22.png

[Money]

http://www.tropicaltidbits.com/analysis/models/gfsp/2014121818/gfsp_z500_mslp_us_23.pngHmm..

 

 

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014121818/gfsp_z500_mslp_us_24.png

 

http://www.tropicaltidbits.com/analysis/models/gfsp/2014121818/gfsp_z500_mslp_us_25.png

[Grizzcoat]

this is one of most confusing times I have seen with models in the medium range. As Tom mentioned-- guidance is really going to struggle until these systems get closer to shore or on. Usually under 96 hours has been in my experience when you start to see them get locked on-- it maybe 72 in this type of pattern.

[Money]

18z PAR GFS has a 966 L in N. MI

 

It's all going to come down to how far the northern stream can dig, and equally as important, how strong the southern stream can get.

[tim the weatherman]

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
249 PM CST THU DEC 18 2014

NEXT WEEK A SIGNIFICANT PATTERN CHANGE IS FORECAST TO TAKE PLACE
ACROSS THE NORTHWESTERN HEMISPHERE WITH SIGNIFICANT LONG WAVE TROUGH
SETTING UP OVER THE UPPER MISSISSIPPI VALLEY AND EVENTUALLY THE
EASTERN CONUS. THE SYSTEM THAT WILL EVENTUALLY CARVE OUT THE DEEP
TROUGH OVER THE REGION IS ACTUALLY THE SAME SIGNIFICANT STORM THAT
JUST AFFECTED JAPAN...SO IT HAS A LONG FAIRLY AND DATA SPARSE REGION
OF THE PACIFIC TO TRAVERSE BEFORE ARRIVING IN OUR AREA. AS IS
TYPICAL WITH LARGE SCALE PATTERN CHANGES...THERE HAVE BEEN
SIGNIFICANT RUN TO RUN MODEL VARIATIONS IN THE HANDLING OF THE
DETAILS OF THIS CYCLONE/DEVELOPING TROUGH AND WOULD ANTICIPATE
FURTHER CHANGES IN LATER MODEL RUNS.

AT THIS POINT...FAIRLY HIGH CONFIDENCE THAT A STORMIER AND
EVENTUALLY COLDER PATTERN WILL SETTLE IN NEXT WEEK. INITIALLY LOOKS
TO BE MORE OF A RAIN/SHOWER EVENT EARLY IN THE WEEK TRANSITIONING TO
MORE FLURRIES/SNOW SHOWERS AS THE UPPER LOW SETTLES IN OVER THE
REGION. LATEST RUNS REALLY ARENT LOOKING TOO FOREBODING FOR
SIGNIFICANT SNOWFALL...BUT AT THIS POINT WOULD REALLY CAUTION ABOUT
LATCHING ONTO ANY ONE SOLUTION AS THERE WILL LIKELY BE MORE MODEL
VARIABILITY IN THE COMING DAYS. CERTAINLY SOME POTENTIAL EXISTS FOR
TRAVEL IMPACTS HEADING INTO THE MIDDLE OF NEXT WEEK.

IZZI

[GDR]

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

249 PM CST THU DEC 18 2014

 

NEXT WEEK A SIGNIFICANT PATTERN CHANGE IS FORECAST TO TAKE PLACE

ACROSS THE NORTHWESTERN HEMISPHERE WITH SIGNIFICANT LONG WAVE TROUGH

SETTING UP OVER THE UPPER MISSISSIPPI VALLEY AND EVENTUALLY THE

EASTERN CONUS. THE SYSTEM THAT WILL EVENTUALLY CARVE OUT THE DEEP

TROUGH OVER THE REGION IS ACTUALLY THE SAME SIGNIFICANT STORM THAT

JUST AFFECTED JAPAN...SO IT HAS A LONG FAIRLY AND DATA SPARSE REGION

OF THE PACIFIC TO TRAVERSE BEFORE ARRIVING IN OUR AREA. AS IS

TYPICAL WITH LARGE SCALE PATTERN CHANGES...THERE HAVE BEEN

SIGNIFICANT RUN TO RUN MODEL VARIATIONS IN THE HANDLING OF THE

DETAILS OF THIS CYCLONE/DEVELOPING TROUGH AND WOULD ANTICIPATE

FURTHER CHANGES IN LATER MODEL RUNS.

 

AT THIS POINT...FAIRLY HIGH CONFIDENCE THAT A STORMIER AND

EVENTUALLY COLDER PATTERN WILL SETTLE IN NEXT WEEK. INITIALLY LOOKS

TO BE MORE OF A RAIN/SHOWER EVENT EARLY IN THE WEEK TRANSITIONING TO

MORE FLURRIES/SNOW SHOWERS AS THE UPPER LOW SETTLES IN OVER THE

REGION. LATEST RUNS REALLY ARENT LOOKING TOO FOREBODING FOR

SIGNIFICANT SNOWFALL...BUT AT THIS POINT WOULD REALLY CAUTION ABOUT

LATCHING ONTO ANY ONE SOLUTION AS THERE WILL LIKELY BE MORE MODEL

VARIABILITY IN THE COMING DAYS. CERTAINLY SOME POTENTIAL EXISTS FOR

TRAVEL IMPACTS HEADING INTO THE MIDDLE OF NEXT WEEK.

 

IZZI

That doesn't sound like the b-word!

[NEJeremy]

That doesn't sound like the b-word!

 

You can have a blizzard with 1/2" of snow. What makes a blizzard is the wind not the amount of snow, and the winds with this storm will be plenty strong

[WBadgersW]

Still 6 days to go. Really anything can happen.

[Grizzcoat]

NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL

249 PM CST THU DEC 18 2014

 

NEXT WEEK A SIGNIFICANT PATTERN CHANGE IS FORECAST TO TAKE PLACE

ACROSS THE NORTHWESTERN HEMISPHERE WITH SIGNIFICANT LONG WAVE TROUGH

SETTING UP OVER THE UPPER MISSISSIPPI VALLEY AND EVENTUALLY THE

EASTERN CONUS. THE SYSTEM THAT WILL EVENTUALLY CARVE OUT THE DEEP

TROUGH OVER THE REGION IS ACTUALLY THE SAME SIGNIFICANT STORM THAT

JUST AFFECTED JAPAN...SO IT HAS A LONG FAIRLY AND DATA SPARSE REGION

OF THE PACIFIC TO TRAVERSE BEFORE ARRIVING IN OUR AREA. AS IS

TYPICAL WITH LARGE SCALE PATTERN CHANGES...THERE HAVE BEEN

SIGNIFICANT RUN TO RUN MODEL VARIATIONS IN THE HANDLING OF THE

DETAILS OF THIS CYCLONE/DEVELOPING TROUGH AND WOULD ANTICIPATE

FURTHER CHANGES IN LATER MODEL RUNS.

 

AT THIS POINT...FAIRLY HIGH CONFIDENCE THAT A STORMIER AND

EVENTUALLY COLDER PATTERN WILL SETTLE IN NEXT WEEK. INITIALLY LOOKS

TO BE MORE OF A RAIN/SHOWER EVENT EARLY IN THE WEEK TRANSITIONING TO

MORE FLURRIES/SNOW SHOWERS AS THE UPPER LOW SETTLES IN OVER THE

REGION. LATEST RUNS REALLY ARENT LOOKING TOO FOREBODING FOR

SIGNIFICANT SNOWFALL...BUT AT THIS POINT WOULD REALLY CAUTION ABOUT

LATCHING ONTO ANY ONE SOLUTION AS THERE WILL LIKELY BE MORE MODEL

VARIABILITY IN THE COMING DAYS. CERTAINLY SOME POTENTIAL EXISTS FOR

TRAVEL IMPACTS HEADING INTO THE MIDDLE OF NEXT WEEK.

 

IZZI

I wish DMX could write discos like the above--- mentioning Japan etc...

[Geos]

Starting to like the chances of a white Christmas in this area now. Not expecting a big storm, but maybe a widespread 2-4" snowfall in on the table for Tuesday into Wednesday.

[tim the weatherman]

.LONG TERM...(FRIDAY NIGHT THROUGH THURSDAY)
ISSUED AT 314 PM EST THU DEC 18 2014

FOCUS OF THE LONG TERM REMAINS ON POTENTIAL STORM NEXT WEEK WITH
LITTLE SENSIBLE WEATHER CONCERNS THROUGH THE WEEKEND GIVEN
PERSISTENT HIGH PRESSURE OVER THE REGION. HERE IS WHAT WE KNOW:

200 KT PACIFIC JET STREAK...CURRENTLY STILL ON THE OTHER SIDE OF THE
INTERNATIONAL DATE LINE...WILL EVENTUALLY WORK ITS WAY INTO THE
CENTRAL CONUS AND CARVE OUT A DEEP LONGWAVE TROUGH. DIGGING TROUGH
WILL BECOME NEGATIVELY TILTED...AND EVENTUALLY CLOSED OFF...BY
CHRISTMAS EVE. STRONG UPPER DIVERGENCE ON THE NOSE OF THIS
CYCLONICALLY CURVED JET STREAK WILL WORK IN TANDEM WITH IMPRESSIVE
DIFFLUENCE AND MIDLEVEL CVA TO SUPPORT A DEEP SURFACE LOW SOMEWHERE
OVER THE GREAT LAKES/NORTHEAST CONUS CHRISTMAS EVE INTO CHRISTMAS
DAY.

WHAT WE DON`T KNOW IS THE EXACT TRACK AND EVOLUTION OF THIS TROUGH
AND ASSOCIATED SURFACE LOW(S). MODEL ACCURACY IN THESE FINER SCALE
DETAILS IS VERY LOW BEYOND 3-4 DAYS...LARGELY DUE TO THE FACT THAT
THE RELEVANT SYNOPTIC DRIVERS ARE STILL OVER THE DATA-SPARSE NORTH
PACIFIC. LATEST 12Z NWP SUITE CONTINUES TO OFFER AN INCONSISTENT
PICTURE REGARDING THE SPECIFIC DETAILS OF THIS EVENT. THAT BEING
SAID...IT CAN BE USEFUL TO NOTE THE TRENDS AND THE TREND OVER THE
PAST FEW CYCLES HAS GENERALLY BEEN A WARMER TRACK FOR OUR CWA AND
LATER PHASING. THIS WOULD RESULT IN THE BULK OF PRECIP FALLING AS
RAIN IN OUR AREA. NOTABLY LACKING WITH THIS EVENT IS A SOURCE OF
VERY COLD AIR UPSTREAM. DEEPENING LOW WILL CERTAINLY PULL IN SOME
BELOW FREEZING TEMPERATURES EVENTUALLY BUT THIS MAY TAKE SOME TIME
AND WITH A SURFACE LOW TRACK DIRECTLY OVERHEAD OR JUST TO OUR
NORTHWEST...MAY ARRIVE AFTER THE BULK OF THE PRECIP/FORCING HAS
EXITED. THIS IS THE SOLUTION CHAMPIONED BY THE LATEST 12Z GFS AND
SIMILARLY BY THE ECMWF...SUGGESTING JUST SOME LIGHT SNOW SHOWERS AND
PERHAPS SOME GUSTY WINDS ON THE 24TH. THOUGH IT SHOULD ALSO BE NOTED
THE LATEST GFS AND ECMWF NOW BRING A SECONDARY LOW THROUGH THE
REGION ON FRIDAY THE 26TH WITH A BETTER CHANCE OF ACCUMULATING
SNOWFALL.

BOTTOMLINE...THERE WILL BE A STRONG STORM SOMEWHERE OVER THE REGION
DURING THE MIDDLE TO END OF NEXT WEEK BUT IMPORTANT DETAILS
REGARDING TIMING...PRECIP TYPES...AND AMOUNTS IN OUR LOCAL AREA
REMAIN UNCLEAR. TO ECHO THE SENTIMENTS OF THE PREVIOUS
FORECASTER...RESTRAINT SHOULD BE EXERCISED IN FORECASTING EXACT SNOW
AMOUNTS AND WITH PLACING MUCH VALUE IN ANY ONE PARTICULAR MODEL
ITERATION. SUFFICE IT TO SAY...ANYONE WITH TRAVEL PLANS DURING THIS
TIME SHOULD STAY TUNED TO THE LATEST FORECAST AND BE PREPARED FOR
HAZARDOUS WEATHER CONDITIONS. (from no ind nws)

[Tom]

Comparing 18z GFS Ensembles from 24 hours ago to today's run...notice it digs the energy farther west and south now compared to yesterday's run.  Slight differences, but bigger implications down the road.

[Money]

18z Ensembles

 

http://mp1.met.psu.edu/~fxg1/ENSPRSNE_18z/f144.gif

[Scott26]

18z Ensembles

 

http://mp1.met.psu.edu/~fxg1/ENSPRSNE_18z/f144.gif

When we see that the ensembles are all over the place that is when we take the Deterministic models with a grain of salt. Obviously, we shouldn't expect much accuracy this far out especially since we have such a complex system with so many moving parts.

[Money]

0z GFS coming in much slower with the northern stream through 72