Winter 2013-14 Pattern Discussion II

[franklin NCwx]

Cmc is still weak and maybe flurries at best. 180 difference compared to the gfs.

[Blue_Ridge_Escarpment]

Cmc is still weak and maybe flurries at best. 180 difference compared to the gfs.

 

I'll take the GFS QPF and the CMC temps....

[mackerel_sky]

Overnight AFD from KGSP

Monitor for the Higher Terrain of NC Mountains.

AREA FORECAST DISCUSSION

NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC

915 AM EST SUN FEB 2 2014

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...

AS OF 145 AM EST SUNDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON

THURSDAY WITH THE UPPER TROF LIFTING TO OUR NORTH AS THE UPPER

PATTERN BEGINS TO FLATTEN OUT AND BECOME MORE ZONAL. OVER THE NEXT

COUPLE OF DAYS...UPPER RIDGING WILL GRADUALLY BUILD OVER THE SE

CONUS AS A SOUTHERN STREAM UPPER TROF DIGS DOWN OVER THE WESTERN

CONUS. THE LONG RANGE MODELS HAVE THIS UPPER TROF APPROACHING THE

FCST AREA BY EARLY SUN WHICH IS DAY 7.

AT THE SFC...A FAIR AMOUNT OF UNCERTAINTY REMAINS WRT THE EVOLUTION

OF THE SFC PATTERN FROM FRIDAY ONWARD. HIGH PRESSURE IS EXPECTED TO

REMAIN OVER THE REGION THRU THURS WITH SOME SORT OF WEDGE PATTERN

BEGINNING TO ESTABLISH ITSELF OVER CENTRAL NC ON FRIDAY. THE MODELS

THEN GENERATE A LOW OVER THE NORTHERN GULF COAST ON SAT AND TRACK IT

NE TOWARDS NEW ENGLAND OVER THE REMAINDER OF THE WEEKEND. THE LATEST

00Z RUN OF THE GFS IS ABOUT 12 HRS SLOWER DEVELOPING THE LOW AND

MOVING IT NE COMPARED TO THE 00Z ECWMF. WITH THE UNCERTAINTY

REMAINING THIS FAR OUT ON DAYS 6 AND 7...NO MAJOR CHANGES WERE MADE

TO THE SENSIBLE FCST. PERIODS OF RAIN...SNOW...SLEET...AND FRZ RAIN

WERE INCLUDED IN THE FCST GRIDS OVER THE HIGHER TERRAIN WITH MOSTLY

RAIN OVER THE REST OF THE CWFA. ALTHOUGH IT IS STILL TOO FAR OUT TO

TRY AND PINPOINT EXACT DURATIONS AND AMOUNTS OF FROZEN PRECIP...SOME

COMBINATION OF P-TYPES LOOKS LIKELY ESPECIALLY OVER THE HIGHER

TERRAIN. TEMPS WILL START JUST BELOW CLIMO WITH HIGHS REMAINING

BELOW CLIMO THRU THE PERIOD AND LOWS LIKELY WARMING ABOVE CLIMO BY

THE WEEKEND.

&&

Wonder what they are seeing to say only higher elevations. GFS 00z was pretty icy. Guess they are leaning on the euro. Their discussion yesterday seemed pretty cold and icy for most of forecast area

[Blue_Ridge_Escarpment]

Wonder what they are seeing to say only higher elevations. GFS 00z was pretty icy. Guess they are leaning on the euro. Their discussion yesterday seemed pretty cold and icy for most of forecast area

 

Yeah it seems like with this setup that the favored CAD areas would be colder than alot of the higher elevations, I was confused by this as well.

[burgertime]

Cmc is still weak and maybe flurries at best. 180 difference compared to the gfs.

 

I don't know how much it means but it's interesting that the CMC is taking one extreme and the GFS last night took another while the 12z took yet another extreme. Euro seems to be holding to the middle of the road so right now I would think it holds the most weight. Models seem to be struggling a lot with this pattern/

[BIG FROSTY]

Well unless the Euro shows something, looks like nothing to worry about anyway. GFS showed devastating Ice storm then 24 hours later  temps nowhere near freezing. lol  If GFS shows  something wintry and has no other model in it's camp it most likely garbage!!!

[nchighcountrywx]

Wonder what they are seeing to say only higher elevations. GFS 00z was pretty icy. Guess they are leaning on the euro. Their discussion yesterday seemed pretty cold and icy for most of forecast area

 

They almost always use a weighted blend, but must have been putting more weight on the ECMWF.

 

Will be interesting to see how they reassess things on the 12z ECMWF that just came in.

 

Update: Taken verbatim, on the front end of the event while precip is falling,  the ECMWF has a hard time even grazing 31 degrees in the NW NC High Country.   On the backside of the Sunday system, there is hardly any upslope snow to speak of.

 

Will have to see if the Wed-Thu storm changes things relative to the weekend and how the ensembles react over the next few days.

 

So far the ECMWF Ensembles as of 0Z suggest a pretty good warm conveyor at 850mb for Saturday around the ridge off shore.

 

http://models.weatherbell.com/ecmwf/2014020200/noram/eps_t850_noram_27.png  (subscription required)

 

Cant see any reason to alarm anyone at this point.  Meanwhile it is a nice warm up outside today.   Enjoy it.

[msuwx]

Well unless the Euro shows something, looks like nothing to worry about anyway. GFS showed devastating Ice storm then 24 hours later  temps nowhere near freezing. lol  If GFS shows  something wintry and has no other model in it's camp it most likely garbage!!!

I don't know that I would say temps are nowhere near freezing on the 12z GFS. In fact, in Mt. Airy, the temp sits at 33 for a large portion of the event. Mid 30s in GSO and mid to upper 30s in CLT.

[Pilotwx]

We are just going to have to wait till the first in the series of storms passes. Before we stop having these wild swings. Ens and Ops can't even agree along with split flow just too much for the models to handle right now.

[beanskip]

Interesting new Euro solution -- first high moves out -- by Day 7, coast low off N.C. coast -- looks like Tennessee Valley special -- temps way too warm in N.C.

EDIT: Actually more of a double barrel low -- from Wilmington N.C. to the NE.

My guess is that most of precip has fallen before temps crash over Tenn./Alabama, et al, but those with access to higher level graphics will need to weigh in.

[BIG FROSTY]

I don't know that I would say temps are nowhere near freezing on the 12z GFS. In fact, in Mt. Airy, the temp sits at 33 for a large portion of the event. Mid 30s in GSO and mid to upper 30s in CLT.

I should have worded it different, I did see it had 33 for a long period, but might as well have 43 as 33, lol  Main point I was trying to make is goes from one extreme to another. I emailed a friend this morning and told him I bet it backs off that Ice storm at 12z because it was all alone on it yesterday. But, Yes I shouldn't said no where near freezing!!! My bad...

[burgertime]

Euro is basically just a coldish rain. 

[WXinCanton]

I should have worded it different, I did see it had 33 for a long period, but might as well have 43 as 33, lol  Main point I was trying to make is goes from one extreme to another. I emailed a friend this morning and told him I bet it backs off that Ice storm at 12z because it was all alone on it yesterday. But, Yes I shouldn't said no where near freezing!!! My bad...

  That is the exact reason the Ensembles are much better at this range almost all of the time.   Look at the ensembles and the trends on them.  Deep breathes

[msuwx]

I should have worded it different, I did see it had 33 for a long period, but might as well have 43 as 33, lol  Main point I was trying to make is goes from one extreme to another. I emailed a friend this morning and told him I bet it backs off that Ice storm at 12z because it was all alone on it yesterday. But, Yes I shouldn't said no where near freezing!!! My bad...

Haha. No problem. Wasn't trying to jump on you at all. Just was clarifying.

[Blue_Ridge_Escarpment]

So what we have learned so far today is that anything from a Winter Storm to cold rain to nothing is still on the table.  Carry on.

[Brick Tamland]

Wild swings in the models. Probably means they are not handling things right like Robert said. I would not be surprised to see it trend colder.

[packbacker]

Interesting run of the Euro, starts diverging fairly quickly after day 4/5 from the GFS. GFS is just much stronger/deeper, Euro isn't but does have a system that is progressive, if you were to combine the models you would have something nice probably.

[SN_Lover]

12z GFS

 

10/20 ensemble members of the GFS show cold air damming for NC

5/20 ensemble members have negative temperature anomalies for NC

 

DT said on facebook the 0z and 6z ensembles were very warm. 

 

operational run 2m temp

[Cold Rain]

Looking at the operational models, after this event, you can flat forget about anymore winter threats as far as the eye can see.

[nchighcountrywx]

Of interest this morning though on the GFS, Ryan Maue did share this:

 

Ryan Maue ‏@RyanMaue14h

@whatdoweseehere that 1044 mb high in Eastern Canada is new for winter -- reminds me of a more famous block pic.twitter.com/5pRV0ewYIc

[nchighcountrywx]

And our afternoon AFD update from the boys at KGSP:

 

000
FXUS62 KGSP 021934
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
234 PM EST SUN FEB 2 2014

 

.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
AS OF 200 PM SUNDAY...WITH SURFACE LOW MOVING RAPIDLY OFF THE
MID-ATLANTIC COAST...AND 1030+ MB SURFACE HOW OOZING EASTWARD ACROSS
THE LOWER GREAT LAKES...COLD AIR WILL SPILL SOUTH ACROSS THE
MID-ATLANTIC AND SOUTHEAST MON NIGHT/EARLY TUE...HERALDING THE ONSET
OF A CLASSICAL COLD AIR DAMMING EVENT. MEANWHILE...AS ANOTHER IN A
SERIES OF SOUTHERN STREAM SHORT WAVE TROUGHS BEGINS TO EJECT OUT OF
THE SOUTHERN PLAINS...MOIST UPGLIDE WILL DEVELOP ATOP THE COLD DOME
DURING THE DAY TUESDAY...WITH UPGLIDE ASSISTED BY A STRENGTHENING
SOUTHERLY UPSLOPE FLOW. ALTHOUGH LIKELY TO CATEGORICAL POPS WILL BE
CARRIED BY TUE AFTERNOON...THIS LOOKS TO BE A LIGHT QPF EVENT...AS
UPGLIDE AND THE UPSLOPE WIND COMPONENT WILL BE RELATIVELY WEAK. WITH
CAD BECOMING ENTRENCHED BY TUE MORNING...FREEZING TEMPS COULD BECOME
LOCKED IN FOR A TIME IN THE CLIMATOLOGICALLY FAVORED AREAS ALONG THE
EASTERN BLUE RIDGE IN NC. THIS WOULD ALLOW FOR THE POSSIBILITY OF AT
LEAST A BRIEF PERIOD OF -FZRA. NAM FORECAST SOUNDINGS FROM THE
NORTHERN MTNS DEPICT A BRIEF PERIOD OF FZRA...WHILE A MAJORITY OF
SREF MEMBER SOUNDINGS DO AS WELL. THEREFORE...WE WILL CONTINUE TO
FORECAST CHANCES FOR ACCUMULATING ICE TUE MORNING. AGAIN...QPF IS
EXPECTED TO BE LIGHT...SO ANY ICE ACCUMS WOULD BE VERY LIGHT. THE
MAX TEMP FORECAST FOR TUE WILL BE VERY TRICKY...AS HIGHS WILL OCCUR
IN MOST AREAS AT 12Z...WITH SLOWLY FALLING TEMPS (INTO THE MID/UPPER
30S) EXPECTED THROUGHOUT THE DAY.

CAD WILL BEGIN TO ERODE TUE NIGHT...AS SURFACE HIGH WEAKENS AND
MOVES OFF THE NEW ENGLAND COAST...AND SURFACE LOW LIFTS NORTHEAST ON
THE WEST SIDE OF THE SOUTHERN APPALACHIANS. UPGLIDE WILL GRADUALLY
WEAKEN AS A RESULT. ADDITIONALLY...FORCING ALONG THE COLD FRONT TO
OUR WEST WILL WEAKEN...AND ATTENDANT SHOWER BAND WILL BEGIN TO LOSE
ORGANIZATION AS IT MOVES INTO FAR WESTERN NC TOWARD 12Z WEDNESDAY.
NEVERTHELESS...WILL CARRY CATEGORICAL POPS IN THE FAR WESTERN MTNS
PRIOR TO 12Z...WITH POPS DIMINISHING TO THE LOW END OF THE LIKELY
RANGE WED MORNING AS THE FRONT SWEEPS ACROSS THE AREA. TEMPS WILL
WARM QUICKLY ON WED...REACHING THE 60S IN MOST AREAS OUTSIDE THE
MTNS BEFORE THE STRONGER COLD ADVECTION SETS IN LATE IN THE
DAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM EST SUNDAY...ONCE AGAIN THE EXT RANGE EXHIBITS GOOD
CONFIDENCE IN THE FIRST COUPLE PERIODS AND LOWERING CONFIDENCE
THEREAFTER. THE ONGOING NWFS WILL COME TO A QUICK END WED NIGHT AS
VERY DRY ARCTIC AIR MIXES IN AHEAD OF A 1035 MB HIGH. H85 TEMPS DROP
TO AROUND THE -3 C RANGE DURING THE DAY THU AND THIS WILL HELP
KEEP MAX TEMPS ABOUT 5 DEGREES BLOW NORMAL IN GOOD SUNSHINE. THERE
ARE SIMILAR LOOKING MOISTURE FLUXES BTW THE OP MODELS WITH THE SRN
BOUNDARY...YET THE 12Z GFS IS MUCH MORE AGGRESSIVE WITH THE NORTHWARD
TRANSPORT INTO THE CWFA. THE IMPENDING WRN CYCLOGENESIS AND CAD
DEVELOPMENT HAVE SIGFNT DIFFERENCES AMONG THE GUIDANCE AS WELL BY 12Z
FRI AND THE AMOUNT OF ISENT LIFT WITH THE PRONOUNCED GFS CAD IS A
NOTICEABLE OUTLIER. THUS...POPS HAVE BEEN ADJUSTED DOWN A LITTLE FOR
THE ONSET PRECIP THU NIGHT.

THE CAD WILL STRENGTHEN DURING THE DAY FRI AND PERSIST UNTIL AT
LEAST SAT AFTERNOON...HOWEVER THERE ARE BIG DIFFERENCES IN THE
THERMAL PROFILES BTW THE GFS/ECMWF. THE LATEST ECMWF HAS BACKED OFF
IT/S EARLIER COLDER SOLN AND IT/S SOUNDINGS NOW INDICATE ALL -RA FOR
MOST OF THE FCST AREA EXCEPT THE HIGHER NC MTN REGIONS AND PERHAPS
THE EXTREME NW PIEDMONT WHERE FREEZING PRECIP FINALLY CATCHES UP
WITH LOW SFC TW/S LATE FRI INTO SAT MORNING. THE GFS BOURGOUIN
METHOD SOUNDINGS ON THE OTHER HAND...INDICATE THE EVENT SHOULD BE A
MIX SN/IP/ZR ACROSS THE MTNS LATE FRI SPREADING INTO THE NRN FHILLS
AND PIEDMONT BY SAT MORNING. PARTIAL THICKNESSES NOMOGRAMS ARE A
LITTLE CONFUSING...SHOWING A GOOD CASE FOR MAINLY -ZR...WHICH
CONTRADICTS THE WARM LAYERED ENERGY PROFILES. IN ANY CASE...THERE
STILL LOOKS TO BE A GOOD CASE FOR A WINTRY EVENT FRI/SAT ACROSS THE
NRN ZONES...HOWEVER THE DEGREE OF AVAILABLE PRECIP...THERMAL
PROFILES AND EVENTUAL CAD TYPE ARE STILL UNCERTAIN RIGHT NOW. A COLD
FRONT SHOULD SCOUR THE CAD SAT NIGHT WITH A COLDER CA/CP AIRMASS MIX
OCCURRING SUN. WITH THE MOIST CAD AND AIRMASS CHANGE...TEMPS SHOULD
HAVE A RELATIVELY LOW DIURNAL CURVE...WITH MAXES ABOUT 10 DEGREES
BLOW NORMAL AND MINS RIGHT AROUND NORMAL EACH DAY.

 

&&

[packbacker]

Looking at the operational models, after this event, you can flat forget about anymore winter threats as far as the eye can see.

Looks very bleak in the LR but I am still hanging by a thread for this 2/9 potential. The Euro ENS mean looks very similar to the GEFS mean. Still a long shot but think maybe we can see a few front end flakes with light icing before it's all washed away. If I was in the mtns I would be very interested still could be a nice storm. Definitely looks like another BOS 10"+ event, which would be like the seventh going back to last Feb.

[HKY_WX]

i really like the look of the HP setup on this one. again, such as the last storm, patience is a virtue. snow scenario has never been likely, but a snow to ice scenario or ice scenario is still very much in play here. i think the models will continue to swing wildly as they resolve the s/w complex on the west coast.

[GaWx]

Today, I looked at the strongest that the center of each CAD'ing high was (most centered in/near the NE US) just before or near the start of the ZR for 29 ATL major ZR's since the late 1800's. Here they are in descending order in mb's:

 

 

1048, 1947, 1047, 1045, 1045, 1042, 1042, 1040, 1040, 1039, 1038, 1038, 1038, 1038, 1037, 1037, 1036, 1035, 1035, 1034, 1034, 1034, 1033, 1031, 1031, 1030, 1029, 1027, 1027

 

Median 1037; Avg.: 1037; Mode 1038 followed by 1034; highest concentration 1034-8

 

 So, most major ATL ZR CAD highs (69%) are actually weaker than 1040 mb at their strongest, which many people likely don't realize. More are actually within the narrow 1034-8 range than 1040+. Also, about as many are within the 1027-34 range as 1040+.

 

Edit: Interestingly, I found no correlation between strength of high and how bad each ZR was in ATL!! This surprised me.

 

***Edit #2: That being said, I assume that the # of NE highs near 1027-34 far outnumbers the # at 1040-1048. So, the % of 1040-48 highs producing a major ZR at ATL is likely a good bit higher than that for 1027-34, which would be intuitive.

[dsaur]

Looking at the operational models, after this event, you can flat forget about anymore winter threats as far as the eye can see.

Ok, Mr. It will be warm   The models folks rely on are proving unfathomable.  Changing from run to run.  What do we look too when models are confusing?  Climo.  What does Climo say?  Well, is it winter?  Then it is more likely to be cold than warm...the last few years not withstanding, lol.   What has it been doing lately.  Since March, the highs have come down and the water run underneath.  Has anything happened to stop that general motion?  Don't know, but don't think so.  So...I'm not looking for warm, and I'm betting, if you are betting, you don't either   I mean we've got arctic waves, and split flows, it's the dead of winter, anything goes....... but warmth...no warmth allowed.  T

[dsaur]

Larry, I'd been reading NEGa's ideas about how deep the cad gets in his yard by pressure in the highs, with interest. I'd not paid attention to what pressure it takes to push one into here.  I've gone more by where it's freezing.  If I'm 34, the Lookout's most likely getting freezing rain.  If La Grange, is 34 then I might be getting freezing rain.  Now I'm curious if the pressure has less to do with it, at first, than the placement, and wind strength.  Some time's they just push on through here, against the waa, and sometimes I stay on the edge. I just assumed the stronger high, had the stronger winds, but I guess not necessarily make it, or break it colder.  T

[mackerel_sky]

Brother Joe Bastardi hints of a big winter storm next weekend near the bite of New England and New Jersey:

Subscribers:

http://www.weatherbell.com/premium/joe-bastardi/why-the-ecmwf-is-wrong-next-weekend

Boy things can sure change over 12 hrs?!! He flops like a fish. This morning he tweeted about the storm not being able to cut through the monster high and looking like his doodle maps.?! I'm assuming that would have to happen to get snow where he is talking about now. CAD signal still showing, just not as cold 35-40. Can def trend colder

[Tacoma]

things look so good one minute for a southeast snow storm to nothing at all the next day.  Robert seems to think a winter storm for the southeast, I'm pulling for Robert on wxsouth weather.  says the Euro will catch on eventually.

[GaWx]

 

Larry, I'd been reading NEGa's ideas about how deep the cad gets in his yard by pressure in the highs, with interest. I'd not paid attention to what pressure it takes to push one into here.  I've gone more by where it's freezing.  If I'm 34, the Lookout's most likely getting freezing rain.  If La Grange, is 34 then I might be getting freezing rain.  Now I'm curious if the pressure has less to do with it, at first, than the placement, and wind strength.  Some time's they just push on through here, against the waa, and sometimes I stay on the edge. I just assumed the stronger high, had the stronger winds, but I guess not necessarily make it, or break it colder.  T

 

 Well, based on the study I just did today, the highest pressure at the center of the high (usually in /near the NE US) is not all that correlated (if at all) with how bad it gets in ATL. So, perhaps the pressure has less to do with it than we thought. At a minimum, I think this tells me it is a lot more complex than just looking at the strongest of the center of the NE high. For example, the great 1973 ZR was associated with just a 1037 mb peak in Ontario of all places. The NE US's pressures were actually lower. The highest was in the northern Plains (1044), which really wasn't in a position to CAD into the SE. It was a pretty odd setup with no unusually strong CAD from what I saw.

 

1/1973 was associated with a Miller A, which was the case for only 7 of the 29 major ATL ZR's.

 

Edit: Lowest pressure for center of highs associated with just the seven Miller A major ZR storms: weaker on average, which seems somewhat intuitive

 

With Miller A: 1042, 37, 37, 34, 30, 27, 27. Median  only 1034. Mean only ~1033.5. The mean and median for all 29 is a good bit higher at 1037.

[superjames1992]

So, after a quick glance at the 12z models, we have the GFS sending the low to Illinois, we have the Euro doing an Apps Runner kind of deal, and we have the Canadian squashing the system so there's hardly any precip at all (maybe snow showers?).  Hmm...

 

EDIT: And the NAVGEM (NOGAPS) keeps the system suppressed, aside from maybe rain and/or snow showers.  No surprise there since that's its bias, IIRC.