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Winter Storm 1/6 - 1/8, 2017

StoneColdWeatherAustin

By StoneColdWeatherAustin,
in Southeastern States

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nchighcountrywx

nchighcountrywx

Posted
Posted

WPC 

PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
406 AM EST WED JAN 04 2017

VALID 12Z WED JAN 04 2017 - 12Z SAT JAN 07 2017


DAYS 1 THROUGH 3...


...WEST COAST/INTERMOUNTAIN WEST...

ONE OF THE MORE ANOMALOUS PATTERNS CONCERNING PAC AND SUBTROPICAL
MOISTURE TRANSPORT WILL IMPACT THE WEST ON WED AND THURS TO
DELIVER WIDESPREAD HEAVY SNOWFALL. A DOUBLE CLOSED LOW STRUCTURE
OVER THE EAST CENTRAL PAC AND ALONG THE NW COAST WILL LOCK IN DEEP
MOIST WRLY FLOW INTO CA AND SPREADING DOWNSTREAM. THE GENERAL
TRAJECTORY ON WED WILL BE INTO NRN/CENTRAL CA AND SPREADING
DOWNSTREAM INVOF THE POLAR/ARCTIC BOUNDARY FROM NRN/CENTRAL NV
INTO NRN UT/SRN WY AND CO BEFORE REACHING THE CENTRAL HIGH PLAINS.
THERE IS NOT MUCH SPREAD IN THIS SCENARIO WHICH BLASTS THE ENTIRE
SPINE OF THE SIERRA INTO THE NRN WASATCH AND MUCH OF THE CO
ROCKIES. THEN ON THURS... THE CLOSED LOW ALONG THE WEST COAST
FLATTENS AND BEGINS TO GET CAUGHT UP IN THE WESTERLIES TO DIG
SOUTH AND EAST TOWARD THE FOUR CORNERS REGION. THUS THE FOCUS FOR
HEAVY SNOWFALL WILL SHIFT SOUTH FROM GENERALLY THE CENTRAL/SRN
SIERRA INTO THE SRN WASATCH AND SRN ROCKIES... WHILE BLEEDING OUT
INTO THE SRN HIGH PLAINS. WPC FELT VERY CONFIDENT IN THE EXTREMELY
HEAVY SNOW ACCUMULATIONS BOTH DAYS... MAINLY BASED ON A COMBO OF
THE GFS/ECMWF. THE BOTTOM LINE IS THE NEXT TWO DAYS WILL BE A HIGH
END EVENT FOR THE WEST WITH LIKELY RECORD SNOWFALL AMOUNTS FOR THE
TERRAIN.

...GREAT LAKES...

LAKE EFFECT SNOW WILL BE LIKELY DOWNWIND OF THE GREAT LAKES OVER
THE NEXT THREE DAYS WITH THE GENERALLY TRAJECTORY BEING SOUTH AND
WEST. A DEEPENING AREA OF LOW PRESSURE NEAR THE ERN LAKES WILL
LIFT NORTH ON WED TO LOCK IN DEEP CYCLONIC FLOW. THE SPOTS FOR THE
HEAVIEST ACCUMULATIONS WILL BE UPSTATE NY NEAR THE TUG-HILL
PLATEAU OFF ONTARIO... INTO SWRN NY STATE OFF ERIE AND NEAR THE
KEWEENAW PENINSULA/ERN UP OF MI AND NWRN LOWER MI.

...OH/TN VALLEYS INTO MID ATLANTIC AND COASTAL NORTHEAST...

UPPER DYNAMICS STREAMING FROM THE PAC THROUGH THE INTER-MOUNTAIN
WEST WILL EJECT OUT INTO THE CENTRAL PLAINS/MID MS VALLEY... AHEAD
OF THE NEXT SHORT WAVE DRIVING THE NEXT ARCTIC AIR MASS SURGE INTO
THE UPPER MIDWEST. A SHIELD OF LIGHT TO MDT SNOW WILL SPREAD
EASTWARD ACROSS THE OH/TN VALLEYS THURS AFTN/EVENING FOR MINIMAL
ACCUMULATIONS WITH SOME SLIGHT OROGRAPHIC ENHANCEMENT INTO THE
CENTRAL APPALACHIANS OF WV INTO THE LAUREL HIGHLANDS OF PA.
OVERNIGHT THURS... UPPER DYNAMICS REACHING THE NC COASTLINE WILL
INDUCE AN AREA OF LOW PRESSURE TO ALLOW ANOTHER PRECIP SHIELD TO
FLOURISH OVER THE MID-ATL REGION. THE LOW WILL PRESS NORTH AND
EAST RAPIDLY WHILE DEEPENING AND A THREAT OF LIGHT ACCUMULATIONS
WILL BE POSSIBLE INVOF THE DELMARVA BEFORE THE PRECIP EXPANDING
PRECIP SHIELD MOVES OFFSHORE. THIS MEANS POSSIBLE ACCUMULATIONS OF
UP TO AN INCH ALONG THE I95 CORRIDOR FROM DC TO PHL TO NYC WITH
LOCALLY HEAVIER AMOUNTS OVERNIGHT THURS INTO FRI MORNING. THERE IS
ALSO A SLIGHT THREAT ON FRI THAT THE NRN/NWRN PERIPHERY OF THE
PRECIP SHIELD CLIPS LONG ISLAND... RI AND SOUTHEAST MA BUT
ACCUMULATIONS SHOULD BE MINIMAL.

...SOUTHEAST...

THE THREAT OF FROZEN PRECIP IS INCREASING ON FRI INTO SAT MORNING
ACROSS THE SOUTHEAST AND SOUTHERN MID-ATL STATES. A SHORT WAVE
DIGGING INTO THE UPPER MIDWEST TODAY IS DRIVING ANOTHER SURGE OF
ARCTIC AIR. THE ASSOCIATED COLD FRONT WITH THIS FEATURE WILL SWEEP
TOWARD THE SOUTHEAST COAST OVER THE NEXT TWO DAYS AND EVENTUALLY
STALL. MEANWHILE UPSTREAM... THE CLOSED LOW NEAR THE NW COAST WILL
EVENTUALLY BECOME AN OPEN WAVE... GET CAUGHT UP IN THE WESTERLIES
AND PROCEED DOWNSTREAM TO ARRIVE INTO THE SOUTH BY SAT MORNING.
THE GUIDANCE ALL INDICATE THIS SHORT WAVE ARRIVING BUT VARY ON
DEPTH AND PROGRESSION. HOWEVER... INCREASING BROAD SWRLY UPPER
DIFLUENT UPPER FLOW WILL ALLOW MOISTURE FROM THE GULF OF MEXICO
AND SUBTROPICS TO ADVANCE NORTH AND BEGIN OVERRUNNING INTO THE
COLD SECTOR. THE ECMWF IS THE MOST AMPLIFIED SOLUTION... THUS
ALLOWING MUCH MORE MOISTURE RETURN AND SCOURING THE LOW LEVELS OUT
QUICKER. THE GFS IS FLATTER... THUS NOT AS MUCH MOISTURE RETURN
BUT LOCKING IN THE COLD AIR MORE. THE NAM IS SOMEWHERE IN BETWEEN
AT THIS POINT. WPC WENT WITH A COMPROMISE FOR THE THREAT OF
ACCUMULATION SNOW AND PERHAPS SOME ICING PRETTY FAR SOUTH FROM
PARTS OF AL/GA INTO THE CAROLINAS AND SRN VA. THIS FCST REMAINS
UNCERTAIN BUT THE CHANCES ARE BECOMING GREATER EACH MODEL CYCLE.


MUSHER

 

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SnowGoose69

SnowGoose69

Posted
Posted
8 minutes ago, Raine1212 said:

Went to bed seeing a chance of snow for the Augusta, GA. and wake up to a wintry mix. I prefer the snow, should I be worried about getting a lot of ice.  Don't think I could handle a ice storm again.

No, this is either a snow or rain event there or both.  I don't see a significant snow event for SC/GA as of now after looking at all the data this morning.  I think the GFS is too flat and this thing is going north.  The tough part for that area is if the system is deeper and turns the corner more going north does it result in more moisture as it begins to pull out and produce more snow in that region.  As of now if I was in ATL/AGS/GSP I'd probably pull for the deeper solution because it may bring better moisture and better chance of snow eventually.  The 12Z OP Euro yesterday won't cut it, the 00Z with a bit more deepening might.  The 06Z NavGEM continues to go north.

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burrel2

burrel2

Posted
Posted

I'm starting to get concerned with boundary layer temps over the Savannah river valley friday night. The GFS has insisted on keeping this strip of area as rain until about midnight, which is really cutting down on totals.  It seems odd to me with 850's so cold, especially when it's showing places like atlanta and columbia dropping below freezing very fast. Hopefully it's wrong.

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Jon

Jon

Posted
Posted

Don't focus on Ptypes for Central NC yet. 00z Euro Op running warm at 850c for RDU, for example, 5c too warm at onset. Just a few hours slower and could be all snow for this area. Ptypes we can watch later, loving the trends and setup this morning.


94d4fe0488db32d7fbcd34863bf28f61.png
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Solak

Solak

Posted
Posted

RAH HWO this morning: 

.DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY.

THERE IS THE POTENTIAL FOR WINTRY PRECIPITATION TO OCCUR FRIDAY
NIGHT THROUGH SATURDAY ACROSS SECTIONS OF CENTRAL NC. WHILE ITS
TOO EARLY TO DETERMINE WITH HIGH CERTAINTY THE AMOUNT OF
PRECIPITATION THAT WILL OCCUR, IT DOES APPEAR THAT AREAS OF SNOW
OR A WINTRY MIX OF PRECIPITATION WILL OCCUR ACROSS OUR REGION,
WITH SOME ACCUMULATION POSSIBLE. THE AMOUNT AND THE DURATION OF
THE WINTRY PRECIPITATION WILL BE DETERMINED BY: THE TRACK OF THE
SURFACE LOW, EXPECTED TO PASS TO OUR SOUTH AND SOUTHEAST; AND THE
DEPTH OF THE COLD AIR. THIS IS A CASE WHERE SMALL CHANGES IN
EITHER PARAMETER WILL RESULT IN SIGNIFICANT CHANGES IN THE FORECAST.

RESIDENTS ARE ADVISED TO KEEP ABREAST OF THE FORECAST THROUGH THE
REMAINDER OF THE WORK WEEK.
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SnowDawg

SnowDawg

Posted
Posted

GSP doesn't seem to be buying the Euro at this point according to their discussion.

 

"For now we feel the best choice is to stick with the GFS-like solution, which is more in line with the trends of late; this puts the peak PoPs early Saturday and does not support FZRA or IP within the CWFA border. Accums are based mostly on WPC QPF and a 12:1 ratio; this would be slightly above climo, which seems likely based on the exceptionally cold profiles."
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DopplerWx

DopplerWx

Posted
Posted

good to see the 06z gfs come in nw with the precip shield once again, eager to see todays run as the s/w should be onshore and sampling will not be an issue.  can't ask for much better of a look at this point if you are in nc.  the euro temps concern me a bit but the gfs has remained consistent over the past 2 days and shows an all snow solution.  we will see.

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strongwxnc

strongwxnc

Posted
Posted
32 minutes ago, SnowDawg said:

GSP doesn't seem to be buying the Euro at this point according to their discussion.

 

"For now we feel the best choice is to stick with the GFS-like solution, which is more in line with the trends of late; this puts the peak PoPs early Saturday and does not support FZRA or IP within the CWFA border. Accums are based mostly on WPC QPF and a 12:1 ratio; this would be slightly above climo, which seems likely based on the exceptionally cold profiles."
 

Good idea to stick with GSP thoughts as we slide closer to the event. 

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Jon

Jon

Posted
Posted
The NAM wants to keep disappointing folks...what gives?  I realize it is still outside of 60 but geesh


My understanding the LR Nam has been performing pretty bad with precip and precip expansion, even in short lead times. Someone can comment. I'd like to look how it verified versus the GFS and Euro on latest rain storm the SE had but don't have time. I can't trust it until the Euro backs off on overall precip.


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SnowNiner

SnowNiner

Posted
Posted
3 minutes ago, strongwxnc said:

Good idea to stick with GSP thoughts as we slide closer to the event. 

At this point that makes sense...GFS has been consistent with the most trough separation and temp profiles, it's just been correcting NW a little over time as expected.  EURO still jumping around a bit it seems like.  Best case scenario I think for mby is GFS wins and keeps the NW trend a bit longer. 

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Tacoma

Tacoma

Posted
Posted
1 minute ago, olafminesaw said:

If the Euro doesn't adjust south at all at 12z I think its safe to say the gfs is to far south, especially if it adjusts north at all.

Just from past experience I think we're about to see a pretty good NW jog, would be surprised if we don't.

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griteater

griteater

Posted
Posted
31 minutes ago, mackerel_sky said:

Is the blue line the snow line? 540 line? This would be way too warm!

Mac a good rough estimate for the snow line in our area in this setup is 543, so a little south of that 540 line.  Of course, looking at soundings as we get closer is the best course of action for a particular location

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Buddy1987

Buddy1987

Posted
Posted

I like the look of the NAM thus far. At 26, you can see the s/w is stronger out in northern CA, while the northern stream energy is kind of leaving it somewhat. I have a feeling this may be a good run here coming up in later slides.

 

Edit: at 29, it is even more pronounced now with the s/w out over CA. 

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