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Winter 2014-2015 Pattern Discussion Thread III


BIG FROSTY

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Also GFS PARA I think has the right of it more aloft. You can see both tonight and last night it's dragging that 850 line further south the closer we get to the event at the onset. I think this starts as SN/IP for many before switching over to ZR. 

 

Yeah 6z PARA looks very close to starting as snow in WNC while column temps on the 6z GFS don't really support anything other then a cold rain.  Freezing line stays above 700mb but keeps temps around 3-5c below.  It doesn't look like the GFS thinks WNC will be effected by the wedge nearly as much which is very common, but it is a crapshoot right now.  If the high ticks a bit stronger WNC could really be a mess along with much of NC.  Anyone on the VA/NC line looks to be in the best position for wintery precipitation imo as of now.

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I thought Euro took a big step to the GFS solution....it's just a little delayed. Also GFS PARA looked fantastic. Much colder aloft so it's closer to snow for a lot in NC...then it has an ULL drop in which would bring more snow to NC. I really think after Monday is our first real shot at some snow. Euro had a similar look at the end of it's run as well. 

RAH mentions the later(Monday) chance for wintery precip. 

 

USUAL TIMING DIFFERENCES DURING THE MEDIUM RANGE ARE EXACERBATED BY

UNCERTAINTIES WITH HOW QUICKLY THE AFOREMENTIONED BAJA LOW

EJECTS...SUCH THAT FORECAST CONFIDENCE IS BELOW AVERAGE WITH RESPECT

TO HOW QUICKLY MOISTURE ARRIVES AND INTERACTS WITH THE COLD HIGH(S)

OVER THE EAST. THE CURRENT FORECAST FAVORS TIMING LATER SUN-SUN

NIGHT...WHICH WOULD FAVOR MOSTLY LIQUID THROUGH MON. IF

PRECIPITATION WERE TO ARRIVE EARLIER IN THE DAY SUN...FREEZING RAIN

WOULD BE PROBABLE OVER MUCH OF THE PIEDMONT. LONGER RANGE GUIDANCE

FAVORS FURTHER NORTHERN STREAM AMPLIFICATION...SUCH THAT YET ANOTHER

ARCTIC COLD FRONT WOULD USHER A FRESH ARCTIC HIGH INTO THE MIDDLE

ATLANTIC AND NORTHEAST LATE MON-MID-WEEK...WHICH WOULD (RE-

)INTRODUCE A THREAT OF WINTRY PRECIPITATION...IF MOISTURE LINGERS

OVER NC...MON NIGHT-TUE.

 

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Folky folks,

 

For the LR the models seem to be trending towards a coastal low at 10 days. This could be our shot at snow instead of ice. The Euro EPS is improved with the anomaly signature on this day and there is tons of energy involved with this system that some operationals are having trouble with. I think this is a "perfect timing" type of system where the placement of the high and the moisture on the backside of the low can give NC/SC some winter wx. Whether or not this can trend into a stronger system and/or bomb remains to be seen but I like the signature showing up. There is a ton of energy involved with this so solutions will change as we get closer, maybe for the better.

 

00z Euro EPS

NdSoVHI.png

 

00z Euro Vorticity

JxAkyRW.png

 

06z GFS PARA

BZ8VvDk.png

 

Euro weeklies had this system as well. The only issue may be cold but this far out who knows, the trend is there for some coastal system during this time frame and it's on time with what would be our next cold shot, although not as deep/strong as this coming one this week, which is a good thing because we won't have suppression if this system decides to ramp up.

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Jon, I was just about to comment on that. Depending on which model you believe, there is high pressure building across the north or a pesky low up there. Like you said, the good thing is, there is a strong signal across many model/ens suites for a storm at that time in that area. Something to keep an eye on for sure.

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ya, Jon, I agree...if you are looking for a "Big dawg" storm, its not happening this weekend...  Just not going too.  That will be a purely light, but most effective way, to get ZR to accumulate.  The potential for a bigger storm is there mid next week, it appears.

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It will be interesting to see the GFS products today.  The EURO is stubborn on this, the CMC is somewhat there, not quite...I MAINLY account for it not being to see a proper wedge, so I count that more toward the GFS side.  We shall see.  Lots of time to watch this, but shockingly we have another american vs the the world debate.  Who will win?

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So is the Euro showing a miller A? Or the GFS ? Does it start in the gulf and move off the Carolinas? I thought yesterday, it was looking like some strung out energy and overrunning ?

I guess you can say Miller A although the low is weak (1008mb off the coast of wilmington) and slides off into the atlantic without touching the NE...so I would go with the Euro was kinda screwy this run really giving that little bit of energy all it can and got it a little ramped up. We'll see what the 12z does with it.

 

Jon, I was just about to comment on that. Depending on which model you believe, there is high pressure building across the north or a pesky low up there. Like you said, the good thing is, there is a strong signal across many model/ens suites for a storm at that time in that area. Something to keep an eye on for sure.

Yeah definitely something to watch. The models haven't backed off the solution since I posted about them on the 4th, which is a good sign. Several GFS ens members have some kind of coastal storm, with a few giving snow to NC and the SE. It will be interesting to see how models further develop this storm but I know all the focus is on the first one so just want to keep people updated on the potential fireworks near mid-month as well. For those who thought winter was cancelled they should be getting a wake-up right now.

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I thought Euro took a big step to the GFS solution....it's just a little delayed. Also GFS PARA looked fantastic. Much colder aloft so it's closer to snow for a lot in NC...then it has an ULL drop in which would bring more snow to NC. I really think after Monday is our first real shot at some snow. Euro had a similar look at the end of it's run as well. 

 

Yep, that's exactly what I'm seeing, and the primary difference in the various solutions comes down to how fast the piece of energy sitting off the Baja California emerges into the mean flow... 

wv.jpg

 

 

The ECMWF & GEM are as usual, much slower/further south compared the GFS suite & the Parallel, and knowing how slow the Euro is w/ disturbances in the southwestern US (& the GEM as well, often is worse than the Euro in fact), I'm inclined to think the icy solution that has been consistently offered by the GFS/Para will win out. We'll have a better handle on this system once a trough sitting back over the Gulf of Alaska erodes the PNA ridge enough to create a weakness for the system to slip back eastward & come ashore in northern Mexico.

Model-Comparison-Jan-6-2014-0z-96hrs-Ove

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Well.....it looks like CAE is paying attention  :) 

 

.LONG TERM /FRIDAY THROUGH MONDAY/...
YET ANOTHER SHORTWAVE MOVES THROUGH THE PERSISTENT BROAD UPPER
TROUGH OVER MUCH OF THE COUNTRY ON FRIDAY WHICH WILL RESULT IN A
BRIEF RETURN TO SOUTHWESTERLY SURFACE FLOW. THIS WILL ALLOW SOME
MODIFICATION OF THE ARCTIC AIRMASS AND RESULT IN WARMER
TEMPERATURES AIDED BY MOSTLY SUNNY SKIES...THOUGH TEMPERATURES
WILL REMAIN WELL BELOW NORMAL. ANOTHER REINFORCING FRONT WILL
SLIDE THROUGH THE FORECAST AREA FRIDAY NIGHT WITH WINDS RETURNING
TO THE NORTHEAST. OVERNIGHT LOWS FRIDAY NIGHT EXPECTED IN THE 20S.

UNSETTLED WEATHER ARRIVES LATE IN THE WEEKEND INTO EARLY NEXT WEEK
AS THE UPPER TROUGH FINALLY BREAKS DOWN AND MID LEVEL 500MB FLOW
BECOMES MORE ZONAL AND CONFLUENT OVER THE EASTERN PART OF THE
COUNTRY. THIS WILL RESULT IN STRENGTHENING 1040MB SURFACE HIGH
PRESSURE OVER THE EASTERN OHIO VALLEY AND NORTHEASTERN STATES
WHICH RIDGES DOWN INTO THE SOUTHEASTERN STATES ON SATURDAY. UPPER
LEVEL FLOW BACK MORE SOUTHWESTERLY SATURDAY NIGHT INTO SUNDAY AS
SOUTHERN STREAM ENERGY MOVES ACROSS THE GULF COAST STATES
RESULTING IN THE DEVELOPMENT OF A COASTAL TROUGH OFFSHORE AND
STRENGTHENING COLD AIR DAMMING WEDGE OVER THE FORECAST AREA.

THE GFS IS COLDER WITH THE NEAR SURFACE LAYER AND AS THE WEDGE
STRENGTHENS DUE TO INCREASED ISENTROPIC LIFT OF WARM MOIST AIR
ATOP THE MODIFIED SHALLOW ARCTIC AIR MASS...FORECAST SOUNDINGS
INDICATE POTENTIAL FOR SOME WINTRY PRECIP AND POSSIBLE FREEZING
RAIN ON SUNDAY. THE GFS IS WETTER AS WELL GIVING NEARLY A QUARTER
INCH OF LIQUID PRECIPITATION...WHICH ITS SOUNDINGS WOULD SUGGEST
FALLING AS FREEZING RAIN. THE ECMWF IS LESS AGGRESSIVE WITH THE
MOISTURE RETURN AND QPF AND SLOWER OVERALL WITH THE DEVELOPMENT OF
THE PRECIPITATION AND THEREFORE ALLOWS THE BOUNDARY LAYER TO
BECOME WARMER AND RESULTANT PRECIPITATION IS LIQUID RAIN. THE GFS
HAS BEEN CONSISTENT WITH ITSELF FOR MANY RUNS SHOWING THE COLDER
SOLUTION AND GEFS ENSEMBLE RUNS SHOW SOME SUPPORT FOR WINTRY
PRECIP AS WELL. IN GENERAL MODELS TEND TO HANDLE SHALLOW ARCTIC
AIR POORLY AND WARM TEMPERATURES TOO QUICKLY AND WITH THE DRY
NATURE OF THE AIRMASS WITH WETBULB TEMPERATURES WELL BELOW
FREEZING...THINK THERE IS REALISTIC POTENTIAL FOR FREEZING RAIN OR
SOME TYPE OF WINTRY PRECIP AT THE ONSET SO WILL INCLUDE A MENTION
IN THE HWO THIS MORNING. ALSO TO BE CONSISTENT WITH THE WEATHER
AND TEMPERATURE GRIDS WILL INCLUDE A RAIN/FREEZING RAIN MIX EARLY
SUNDAY BEFORE CHANGING TO ALL RAIN. AGAIN THE PRECIPITATION
CHANCES REMAIN AT SLIGHT CHANCE WITH THIS FORECAST.

PERSISTENT SOUTHWESTERLY FLOW ALOFT CONTINUES INTO EARLY NEXT WEEK
WITH PWAT VALUES RISING TO NEAR AN INCH BY MONDAY WILL KEEP RAIN
CHANCES IN THE FORECAST THROUGH MONDAY. TEMPERATURES REMAIN WELL
BELOW NORMAL ON SUNDAY BUT WARM BACK UP A BIT ON MONDAY.

&&

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Brad Panovich Meteorologist added 2 new photos.
5 mins ·

Sunday ice threat still in the cards, if anything the set-up is becoming more favorable for wintry weather. Still early but the chances of wintry weather are up to around 30% right now. The set-up is still cold & dry surface air with warmer air above that. This is is going to be sleet and freezing rain. The threat is still ice. Stay tuned!

10906099_805329766206148_881364791395055
10896886_805329776206147_311275963702904
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^ That write-up from Columbia was good.  The northern and southern stream interaction & confluence pattern is different between the Euro and GFS, and the Euro is moving the surface high off the VA/NC coast while the GFS suite is holding the high over the Ohio Valley and into the Northeast in good damming position.  Euro is warmer/drier.  GFS is colder/wetter.

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Hello all. I don't have time to post here a lot but do drop in from time to time. Looking through previous post I saw a few about concern over the ground being frozen for this event so I'm posting the 06Z Para GFS modeled soil temperatures. This is right before precipitation begins to fall over most of the Carolinas.  Looks like frozen ground may be a problem around and to the north of a line from ATL, GSP, CLT, to RDU. This is the avg soil temperature for the top 10cm (4in) so the actual surface temp could deviate a degree or so. In this way this event is somewhat different as usually with freezing rain ground temps outside of the mountains and foothills are warm enough to prevent ice accumulation on paved surfaces.

This is all assuming the evolution depicted by the GFS is correct of course. :)

 

 

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^ That write-up from Columbia was good.  The northern and southern stream interaction & confluence pattern is different between the Euro and GFS, and the Euro is moving the surface high off the VA/NC coast while the GFS suite is holding the high over the Ohio Valley and into the Northeast in good damming position.  Euro is warmer/drier.  GFS is colder/wetter.

Yeah, I agree....RAH had a similar write up I believe...need more model agreement before you go running with this one.

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Hello all. I don't have time to post here a lot but do drop in from time to time. Looking through previous post I saw a few about concern over the ground being frozen for this event so I'm posting the 06Z Para GFS modeled soil temperatures. This is right before precipitation begins to fall over most of the Carolinas.  Looks like frozen ground may be a problem around and to the north of a line from ATL, GSP, CLT, to RDU. This is the avg soil temperature for the top 10cm (4in) so the actual surface temp could deviate a degree or so. In this way this event is somewhat different as usually with freezing rain ground temps outside of the mountains and foothills are warm enough to prevent ice accumulation on paved surfaces.

This is all assuming the evolution depicted by the GFS is correct of course. :)

 

Thanks for posting this UNCCmetgrad.  Great discussion you provided above.  I welcome your continued frequent posting.

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This is the latest regarding this weekend form NWS in Wakefield, VA. They cover the NE section of NC.

LONG TERM /FRIDAY THROUGH MONDAY/...

BELOW NORMAL TEMPS PERSIST THRU THE EXTENDED PERIOD...WITH

INCREASING CHANCES FOR PRECIP LATE NEXT WEEKEND.

NRN STREAM REMAINS ACTIVE...WITH YET ANOTHER SHORTWAVE DIVING OUT OF

THE CANADIAN PRAIRIES OVER THE GREAT LAKES REGION FRI. ASSOCIATED DRY

CLIPPER FRONT WILL PUSH THRU THE REGION LATE FRI INTO FRI EVENING.

IN ADVANCE OF THE FRONT...HEIGHTS/THICKNESSES RECOVER AS H85 TEMPS

RETURN TO ~-5C. HIGHS FRI IN THE UPPER 30S TO LOW 40S. SHORTWAVE

EXITS THE COAST FRI NIGHT AS STRONG 1030-1040MB SFC HIGH PRESSURE

BUILDS OVER THE OH VALLEY. SFC HIGH BUILDS OVERHEAD FRI

NIGHT...REMAINING OVER THE MID-ATLANTIC THRU SUN. LOW LEVEL

THICKNESSES DROP OFF BEHIND THE FRONT...WITH HIGHS SAT ONLY IN THE

MID-UPPER 30S. HIGH PRESSURE RETREATS NWD SUN AS A COASTAL TROUGH

SHARPENS ALONG THE SE COAST. SRN STREAM ENERGY WILL TRACK ACROSS THE

SE SUN...AS MOISTURE INCREASES IN SWLY FLOW. WILL MAINTAIN CHANCE

POPS ACROSS THE REGION SUN INTO MON FOR WAA/OVERRUNNING PRECIP.

MODELS INDICATE THE POTENTIAL FOR MIXED/FROZEN PRECIP SUN NIGHT INTO

MON MORNING...BUT ENSEMBLES SHOW A LARGE SPREAD IN THE THERMAL

PROFILE. TEMPS THRU THE WEEKEND REMAIN COOL...GENERALLY IN THE LOW

40S. OVERNIGHT LOWS THRU THE PERIOD WARM FROM THE UPPER TEENS THURS

MORNING TO THE LOW 30S THRU THE WEEKEND.

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Hello all. I don't have time to post here a lot but do drop in from time to time. Looking through previous post I saw a few about concern over the ground being frozen for this event so I'm posting the 06Z Para GFS modeled soil temperatures. This is right before precipitation begins to fall over most of the Carolinas.  Looks like frozen ground may be a problem around and to the north of a line from ATL, GSP, CLT, to RDU. This is the avg soil temperature for the top 10cm (4in) so the actual surface temp could deviate a degree or so. In this way this event is somewhat different as usually with freezing rain ground temps outside of the mountains and foothills are warm enough to prevent ice accumulation on paved surfaces.

This is all assuming the evolution depicted by the GFS is correct of course. :)

 

 

Hey man, you got red tagged! Congrats!

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^ That write-up from Columbia was good.  The northern and southern stream interaction & confluence pattern is different between the Euro and GFS, and the Euro is moving the surface high off the VA/NC coast while the GFS suite is holding the high over the Ohio Valley and into the Northeast in good damming position.  Euro is warmer/drier.  GFS is colder/wetter.

It was good, and I would like to see more just like this  :D 

 

Yeah, I agree....RAH had a similar write up I believe...need more model agreement before you go running with this one.

Agree

 

Big difference. I suppose it caved towards the euro.

Don't worry......it will change again soon   :P  

Hello all. I don't have time to post here a lot but do drop in from time to time. Looking through previous post I saw a few about concern over the ground being frozen for this event so I'm posting the 06Z Para GFS modeled soil temperatures. This is right before precipitation begins to fall over most of the Carolinas.  Looks like frozen ground may be a problem around and to the north of a line from ATL, GSP, CLT, to RDU. This is the avg soil temperature for the top 10cm (4in) so the actual surface temp could deviate a degree or so. In this way this event is somewhat different as usually with freezing rain ground temps outside of the mountains and foothills are warm enough to prevent ice accumulation on paved surfaces.

This is all assuming the evolution depicted by the GFS is correct of course. :)

 

Congrats on the red tag!!   :clap:

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ot gonna happen this run, as obviously yall have said.  I have said from the get go, It always made me nervous the GFS is the only one showing the icing. *outside of NC*  Not saying this is right, the euro is always right..nothing like that, but it would do good for confidence if they agreed somewhat.  Hope that made sense?   I agree the GFS is only warmer because its drier

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