Central PA/fringes of MD - December 2013 continued

[Rick G]

peer pressure at the NWS <binghamton>:

 

ONLY A BRIEF BRK IN THE ACTION AHD OF THE NEXT SYSTEM. OVERRUNING
PCPN DVLPS LATE FRI NGT AND EARLY SAT UNDER THE RR OF THE UPR JET.
OVERALL THE UPWARD VERTICAL MOTION IS MODERATE AT BEST AND
MOISTURE IS NOT EXACTLY DEEP AS THE INITIAL SOURCE REGION IS THE
UPR PLAINS. THIS SHD RESULT IN LGT SNOWS FOR THE INITIAL HRS OF THE
STORM.

LTR SAT...DEEPER MOSITURE FROM THE GULF ARRIVES AS THE SRN BRANCH
SYSTEM DVLPS A SFC LOW MVG NWRD IN THE TN VLY. SYSTEM HAS DBL SFC
LOWS EARLY ON WITH A LOW OVER OH WHILE A CSTL LOW DEEPENS OVER ERN
NC. LOWS CONSOLIDATE ARND 06Z SUN OVER CSTL NJ AND BEGIN TO DEEPEN
MORE RAPIDLY. GOOD DEEP ELY FLOW DVLPS LATE IN THE GAME AND A PD
OF HEAVIER SNOW SEEMS LIKELY LATE SAT NGT BEFORE THE SNOW TAPERS
OFF SUN MRNG. EVEN SO...BEST UVM IS NOT EXACTLY WELL ALIGNED WITH
THE BEST DENDRITIC GROATH AREA FOR MUCH OF THE STORM. ALSO...
SYSTEM REMAINS AS AN OPEN WV AT THE UPR LVLS SO IS LACKING A GOOD
CHANCE FOR DEFORMATION BANDS DVLPG LATE IN THE EVENT.

EVEN THE NORMALLY ROBUST NAM QPF FCSTS ARE AT HIGH END ADVISORY
LVLS FOR THE STORM LDG ME TO THINK THAT SNOWFALL AMTS WILL BE BLO
WARNING CRITERIA. BEST CHANCE FOR HIER AMTS APPEAR TO BE OVER THE
WRN CATS AND PERHAPS XTTRM NEPA. FURTHER SOUTH...THERE/S STILL THE
RISK OF SOME ICE PELLETS OVER THE POCONOS AND SCRANTON METRO AREA.
FRZG RAIN SEEMS LIKE A MORE REMOTE CHANCE WITH THE NARROW ABV FRZG
LYR AND VERY COLD SFC AIR.

KIND OF HEMMED IN BY WATCHES SO WENT WITH A WATCH FOR THE AREA AS
WELL...BUT MOST LIKELY LOOKING AT A HIGH END ADVISORY.

-- End Changed Discussion --

[psuhoffman]

I never saw such model consensus the past several runs for a long time. if something fails now, then we should probably go back to the old days of forecasting without computers. :-) and this is the 0z runs.

The models do better in this type of pattern and when dealing with stj systems. Things are being driven by larger scale features and waa as the stj runs into the cold being dumped into the conus. They struggle when things are northern branch dominated and they have to deal with timing the embedded sw's in a fast flow and phasing issues. Way more meso scale features to deal with there also. This is a more stable pattern and model performance is better. Same thing happened in 2010. We saw all those storms from well in advance.

[psuhoffman]

I never saw such model consensus the past several runs for a long time. if something fails now, then we should probably go back to the old days of forecasting without computers. :-) and this is the 0z runs.

The models do better in this type of pattern and when dealing with stj systems. Things are being driven by larger scale features and waa as the stj runs into the cold being dumped into the conus. They struggle when things are northern branch dominated and they have to deal with timing the embedded sw's in a fast flow and phasing issues. Way more meso scale features to deal with there also. This is a more stable pattern and model performance is better. Same thing happened in 2010. We saw all those storms from well in advance.

[AllWeather]

Looks like a great storm from the turnpike to the north..mostly snowy QPF. Up in the central counties you'll get the added benefit of being on the northern edge of heavier QPF and the lower edge of great snow ratios. For those south of the turnpike, there will likely be a precip-type battle after sunset tomorrow, but this area could dry slot in time to avoid a messy scenario. We'll see. Overall, this storm has great potential, hitting the areas that were skipped out on the past 2 storms, but still giving everyone in this forum something to cheer about!

[NeffsvilleWx]

Nice pic saussy!

[PennMan]

The new 03Z SREFs took a pretty big swing at getting the very high probs for significant snow (4+ probs) further south to involve pretty much everyone above  the turnpike. CTP has also expanded the watch area to involve the entire CWA. 

 

Threw together a first call map.. wasn't too hard to make for the first two ranges. The vast majority of PA should see at least a 3-6 inch snowfall from this. I tend to think that for the most part the top end on amounts will be about 8 inches, but highlighted a region where some scattered amounts of 9 or 10 inches might show up. Keeping the region within my 6" boundary a bit more narrow than what CTP has for their new snow map. Ultimate track of the low might dictate where precip becomes more broken and where the solid precip shield lingers the longest. Further north might expose southern PA to this while north central sees the heaviest snowfall. Further south could focus heaviest in say, south central PA into the Lower Sus Valley. Tried to keep my map in the middle, folks that end up with the best QPF matched up with the best snow ratios are gonna be who sees 6+. Will have to watch model runs today to make any adjustments. The only regions I really expect mixing to knock things down much is far SW PA and far SE PA, the rest of the area should remain all snow or at least stay all snow for the part of the storm that's going to do the damage. This should be a nice snow event for everyone. 

 

Slide1.png

 

Looks good.  I think the most likely places to see 9-10" are probably the higher elevations of the Endless Mountains and Poconos with the easterly flow giving them a boost...wouldn't shock me to see a 12" report from either location when all is said and done.

[sauss06]

Nice pic saussy!

Thanks you, i just deleted though, i thought i put it in the banter thread as it probaably didn't belong here.

 I'm kind of interested in hearing the northern guys temps overnight, i bet they had to go single digit. Looking more likely of our best snowfall in awhile, looking through my notes 1-21-12 was the last time i had 5".

[mappy]

6z NAM for Westminster, .48 qpf when snowing, but again will be hovering near freezing. Id expect low ratios. I'm thinking 2-4" at my house.

[mappy]

GFS is a litter drier, around .25qpf when snowing

[NortheastPAWx]

Got to love the NAM. From the 6z run for UNV:

 

131214/2300Z 41 12011KT 26.3F SNOW 15:1| 1.4|| 0.00|| 0.00|| 0.094 12:1| 4.1|| 0.00|| 0.00|| 0.35 100| 0| 0
131215/0000Z 42 12013KT 25.8F SNOW 14:1| 2.9|| 0.00|| 0.00|| 0.215 12:1| 7.0|| 0.00|| 0.00|| 0.56 100| 0| 0

[JamieOber]

Hey hey, for all we know they could wind up correct...1-3 was basically what happened last Friday.

There's very little chance of this storm being a widespread 1-3 across PA.

[JamieOber]

Got to love the NAM. From the 6z run for UNV:

 

131214/2300Z 41 12011KT 26.3F SNOW 15:1| 1.4|| 0.00|| 0.00|| 0.094 12:1| 4.1|| 0.00|| 0.00|| 0.35 100| 0| 0

131215/0000Z 42 12013KT 25.8F SNOW 14:1| 2.9|| 0.00|| 0.00|| 0.215 12:1| 7.0|| 0.00|| 0.00|| 0.56 100| 0| 0

:drunk: :drunk:

 

That's crazy.

[mappy]

To add to the weather office snow maps, here is the one from LWX... a little higher than I expected for my part of town.

[heavy_wx]

The forecast GFS sounding for MDT showed an above freezing layer around 950 mb at 00z Sunday which would change those areas and places to the southeast over to sleet/freezing rain. Temperatures at UNV stay just below freezing for the entire period. Snow growth starts out pretty good with some lift Saturday morning in the dendritic snow growth zone, though this layer is not completely saturated and the best lift becomes lower in the atmosphere by the afternoon. The best lift is below the dendritic snow growth zone for MDT as well.

 

The primary lifting mechanism looks to be through isentropic flow with a stout arctic high in place over southern Quebec. The GFS suggests little in the way of frontogenesis will be present until the storm begins to intensify off the coast of southern New England. The Euro does have an area of 850 mb frontogenesis over southern PA, strongest over southeast PA around 00z Sunday. Any mesoscale lifting that does occur in this area may be near the same time when the warmer air at low-levels moves in. It is worth noting that the Euro keeps the entire profile at MDT below freezing at this time.

 

Overall it looks like at least four inches is likely over central regions of PA. We'll be relying mostly on isentropic lift and decent snow-liquid ratios to achieve accumulations. Areas in SE PA may have better mesoscale lift  for a time Saturday evening but ratios will be lower due to aggregation and less favorable snow growth. There also is the risk of a changeover to sleet/freezing rain which could further lower totals in that region. We'll have to watch the boundary layer temperatures to see if the profile can stay mainly below freezing. If that occurs, SE PA could see at least 4" as well.

[sauss06]

Got to love the NAM. From the 6z run for UNV:

 

131214/2300Z 41 12011KT 26.3F SNOW 15:1| 1.4|| 0.00|| 0.00|| 0.094 12:1| 4.1|| 0.00|| 0.00|| 0.35 100| 0| 0

131215/0000Z 42 12013KT 25.8F SNOW 14:1| 2.9|| 0.00|| 0.00|| 0.215 12:1| 7.0|| 0.00|| 0.00|| 0.56 100| 0| 0

 

 

:drunk: :drunk:

 

That's crazy.

wow look at you guys

[NeffsvilleWx]

My prediction:

 

[NeffsvilleWx]

Could someone please post the euro text for LNS?

[mappy]

My prediction:

 

 

ahhh, that map is a classic

[NeffsvilleWx]

ahhh, that map is a classic

 

The US Virgin Islands and a few peninsulas on the western shore really get the shaft with this one. Also, anyone directly on the mason-dixon line is booked for 5-10 inches, regardless of surrounding areas. It's a strange phenomenon that I've picked up on through the years.

[NortheastPAWx]

My prediction:

 

Damn Virgin Islands screw zone strikes again!   

[Superstorm]

That is classic! LMAO

[paweather]

My prediction:

 

OMG LOL!

[Santa Clause]

Neff just made my day lol!! I agree does anyone have euro output for IPT also?

[skiier04]

Holy cow that 6z NAM was incredible for kunv.  Lets see what 12z can do.

[heavy_wx]

KLNS:

SAT 06Z 14-DEC  -6.9    -6.9    1028      79      48    0.00     557     535    SAT 12Z 14-DEC  -5.3    -6.8    1030      84     100    0.01     556     533    SAT 18Z 14-DEC  -1.8    -5.2    1026      87      97    0.06     555     535    SUN 00Z 15-DEC  -1.2    -2.5    1020      96      99    0.33     556     540    SUN 06Z 15-DEC   0.2     2.8    1009      96      29    0.27     553     546    SUN 12Z 15-DEC  -0.4    -1.6    1008      97      43    0.00     547     541    

KIPT

SAT 06Z 14-DEC  -9.1    -9.0    1028      90      94    0.00     553     531    SAT 12Z 14-DEC  -8.7    -9.0    1030      89      99    0.04     553     529    SAT 18Z 14-DEC  -5.3    -8.0    1027      87      99    0.10     552     531    SUN 00Z 15-DEC  -4.8    -5.8    1020      92      97    0.29     551     535    SUN 06Z 15-DEC  -3.4    -0.9    1011      95      88    0.20     548     539    SUN 12Z 15-DEC  -2.3    -4.0    1008      96      35    0.02     544     537    SUN 18Z 15-DEC   0.5    -8.3    1009      69      16    0.00     542     534    

KMDT

SAT 06Z 14-DEC  -7.8    -6.5    1028      79      45    0.00     556     534    SAT 12Z 14-DEC  -5.8    -6.9    1029      87      99    0.02     556     533    SAT 18Z 14-DEC  -2.2    -5.0    1026      86      97    0.07     555     535    SUN 00Z 15-DEC  -1.1    -2.9    1019      96      99    0.33     555     540    SUN 06Z 15-DEC  -0.7     2.2    1010      96      41    0.19     552     544    SUN 12Z 15-DEC  -1.1    -2.6    1009      96      39    0.00     547     540    

KUNV

 

SAT 06Z 14-DEC  -9.8    -6.6    1028      84      67    0.00     554     532    
SAT 12Z 14-DEC  -7.5    -7.6    1029      90      99    0.05     554     531    
SAT 18Z 14-DEC  -5.1    -5.6    1025      89      99    0.11     553     533    
SUN 00Z 15-DEC  -3.1    -4.1    1018      95      97    0.30     551     537    
SUN 06Z 15-DEC  -2.4    -0.4    1010      96      85    0.13     548     540    
SUN 12Z 15-DEC  -0.6    -5.0    1009      94      22    0.01     545     537    
SUN 18Z 15-DEC  -0.3    -9.0    1011      70      21    0.01     543     534  

[NeffsvilleWx]

KLNS:

SAT 06Z 14-DEC  -6.9    -6.9    1028      79      48    0.00     557     535    SAT 12Z 14-DEC  -5.3    -6.8    1030      84     100    0.01     556     533    SAT 18Z 14-DEC  -1.8    -5.2    1026      87      97    0.06     555     535    SUN 00Z 15-DEC  -1.2    -2.5    1020      96      99    0.33     556     540    SUN 06Z 15-DEC   0.2     2.8    1009      96      29    0.27     553     546    SUN 12Z 15-DEC  -0.4    -1.6    1008      97      43    0.00     547     541    

KIPT

SAT 06Z 14-DEC  -9.1    -9.0    1028      90      94    0.00     553     531    SAT 12Z 14-DEC  -8.7    -9.0    1030      89      99    0.04     553     529    SAT 18Z 14-DEC  -5.3    -8.0    1027      87      99    0.10     552     531    SUN 00Z 15-DEC  -4.8    -5.8    1020      92      97    0.29     551     535    SUN 06Z 15-DEC  -3.4    -0.9    1011      95      88    0.20     548     539    SUN 12Z 15-DEC  -2.3    -4.0    1008      96      35    0.02     544     537    SUN 18Z 15-DEC   0.5    -8.3    1009      69      16    0.00     542     534    

KMDT

SAT 06Z 14-DEC  -7.8    -6.5    1028      79      45    0.00     556     534    SAT 12Z 14-DEC  -5.8    -6.9    1029      87      99    0.02     556     533    SAT 18Z 14-DEC  -2.2    -5.0    1026      86      97    0.07     555     535    SUN 00Z 15-DEC  -1.1    -2.9    1019      96      99    0.33     555     540    SUN 06Z 15-DEC  -0.7     2.2    1010      96      41    0.19     552     544    SUN 12Z 15-DEC  -1.1    -2.6    1009      96      39    0.00     547     540    

KUNV

 

SAT 06Z 14-DEC  -9.8    -6.6    1028      84      67    0.00     554     532    

SAT 12Z 14-DEC  -7.5    -7.6    1029      90      99    0.05     554     531    

SAT 18Z 14-DEC  -5.1    -5.6    1025      89      99    0.11     553     533    

SUN 00Z 15-DEC  -3.1    -4.1    1018      95      97    0.30     551     537    

SUN 06Z 15-DEC  -2.4    -0.4    1010      96      85    0.13     548     540    

SUN 12Z 15-DEC  -0.6    -5.0    1009      94      22    0.01     545     537    

SUN 18Z 15-DEC  -0.3    -9.0    1011      70      21    0.01     543     534  

 

Thanks. Euro seems more similar to the 06z GFS than the NAM. Both feature a changeover to fzra around 06z sunday. Nam is colder.

[Cashtown_Coop]

My prediction:

I love it! The red jackpot zone is placed perfectly!

[EasternUSWX]

NAM is a good old shellacking 

[Big Jims Videos]

NAM pounds central and eastern pa from hours 33-39.

[Porsche]

How about Northern Lancaster, how do the temps look?

Thanks