Unprecedented, Destructive October Snowstorm!

By: Zachary Labe , 6:27 PM GMT on October 28, 2011

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"Current Temperature"


"Current Dewpoint"


"Current Surface Map and Weekly History of Jet Stream Position"


"Regional Radar"


"Regional Satellite"


"Regional Advisories"


"12hr Estimated Precipitation"


"Forecast Max Temperatures"


"Forecast Min Temperature"


"Forecast Weather at 2pm"


"Current Storm Reports"


"Forecast Model Links"
-NAM model 12z...Link
-GFS model 12z...Link
-NMM model 12z...Link
-SREF model 9z...Link

This is a pretty quick intro on computer model forecasts along with beneficial links. Computer models use the complex calculus algorithms to print out the forecasts. Despite our complaning with the models, without them much of us would be lost except in the short time. Some of the earlier computer models consisted of the ETA, NGM, and AVN, which forecasted generally less than 84hrs. They were highly inaccurate, but provided a basis. The ETA was actually the computer model that helped meteorologists predicted the "storm of the century" in March of 1993 so well in advance. But now more than ever we have a myriad of computer models available to the general public with many mesoscale models only available to NOAA. Lets start with the general. All current computer models are based off on the Zulu time. Zulu time is also known as UTC or Greenwich time . Generally to forecast timing of storms my special BUFKIT data transitions UTC time to EST time, which is helpful. But BUFKIT is a special download, which I won't get into, but the transition is helpful as for some reason I never am able to understand time zones too well, hahaha. Anyways let me start with each computer model...

-GFS (Mentioned most of all as it is a global model (Global Forecasting System))
~Available in 0z (initiates at 10:30pm), 6z (initiates at 4:30am), 12z (10:30am), 18z (4:30pm)
~Forecasts out to 384hrs
~Typical biases
Cold bias on long range on 18z run
6z and 18z slightly unreliable
Northwest trend on lows within 84hrs of event

-ECMWF (This is another global model run by an international organization (European Centre for Medium-Range Weather Forecasts))
~Available in 0z (initiates at 1:30am), 12z (initiates at 1:30pm)
~Forecasts out to 240hrs
~Typical biases
Overphases lows in 168hr range
Holds too much energy in southwest
Known as extremely accurate within 140hrs

-NAM (Mesoscale short range model)
~Available in 0z (Initiates at 9:30pm), 6z (Initiates at 3:30am), 12z (initiates at 9:30am), 18z (Initiates at 3:30pm)
~Forecasts out to 84hrs
~Typical biases
Highly inaccurate towards the 84hrs
Handles coastal storms very well and southwest overrunning events
Tendency for way too much QPF

Those three above are the most common models for a beginner in computer models, but there are many more. All of the global models consistent of ensemble models also, such as the GFS has a myriad of ensemble (small models) that create a mean solution known as GEFS. They typically are too cold and southeast with low pressures, but some reason the NWS seems to enjoy using them. There are also more global models than the GFS and ECMWF... The UKMET is run by an internation organization and forecasts out to 144hrs. This model typically comes out an hr before the ECMWF and usually is pretty similar to the ECMWF. The ECMWF may also be known as the EURO by the way. There is also a Canadian model known as the GGEM/CMC, which again contains ensemble models. All of the internation models only run 0z and 12z runs. This is probably for the best as all models only receive new upper air data in 0z and 12z runs, so this is why the American model runs of the 6z and 18z are usually worthless. There is also a high resolution Canadian model known as the RGEM, which is very similar to the American NAM. High resolution (mesoscale models) are important as they usually are able to pick up on fine details such as frontogenesis, advection, adebiatic cooling, convection, etc. Some of this high resolution models include the WRF, HIRES NMM, RUC, ARW. They all are usually very accurate, but the WRF and HIRES NMM usually have wet bias.

As mentioned above there are ensemble models which come up with a mean solution instead of using one computer model's algorithms like the global models use. These ensemble mean solution are known as the MREF and SREF with MREF being in the medium range and SREF in the short range. SREF is usually pretty accurate and forecasts within 87hrs of an event. There are also other computer models used for hurricane forecasting, but I will not get into them. For instance one is the GFDL, which you may have heard of. I find I use mainly the GFS, NAM, and WRF/NMM in the summer, but use all of the models in the winter.

A few models to avoid...
JMA
KMA
CAMPASS
DGEX

Here is a list of links for explanations on how to interperate the models...

-PennState E Wall, which runs all of the models
http://www.meteo.psu.edu/~gadomski/ewall.html

-PennState E Wall tutorial on computer models (Check it out)
http://www.personal.psu.edu/adb241/eWallTutorial/ Main.htm

-Severe Weather parameters used on models, explanation
http://www.crh.noaa.gov/sgf/n=severe_weather_chec klist_paper

-Forecasting winter weather
http://www.crh.noaa.gov/lmk/soo/docu/precip_type. php

-NCEP; used to find American Computer models
http://www.nco.ncep.noaa.gov/pmb/nwprod/analysis/

-Severe Weather Models
http://www.wxcaster.com//conus_0012_us_models.htm

-Winter Weather Models
http://www.wxcaster.com/conus_snowfall.htm

-Model Soundings
http://wxweb.meteostar.com/sample/sample.shtml?te xt=KMDT#

The last link is listed above as model soundings which takes all of the data to print out all sorts of information including precipitation type along with dynamics such as Omega. This is very complex and takes some time getting used to. Also you may see this data instead of in charts, it is sometimes used in SKEWT T charts.

I hope all of this information helped out... Keep in mind precipitation amounts is QPF, with 500mb aloft being the jet stream, 700mb aloft measuring relative humidity, 850mb aloft measuring 5,000ft aloft temperatures, 925-1000mb measuring surface temperatures. Generally I would look at the GFS and NAM first to get a hang of it along with reading the tutorial links. Use the 850mb and 2m charts for the GFS especially as they are pretty self explanatory and color coded. You will find some maps for international models are confusing and black and white.

Lower Susquehanna Valley Doppler...

(Courtesy of WGAL)

Follow my 24hr forecasts on Twitter... Link and Facebook... Link.

Please post storm reports in this blog from across the Northeast during the winter storm and please post location of observation in each report...

This blog is in progress. Check back soon...

Winter Forecast 2011-2012... Link

Historic October Nor'easter...
Higher cirrus will begin to flood the northern Middle Atlantic later in the day Friday after high temperatures in the mid 40s with partly cloudy skies. Clouds will begin to thicken and lower Friday night with precipitation moving northward as a 1000hPa coastal low pressure moves up the coast. The low pressure will follow an ideal track up and along the coast and if it were winter... this would be a major snowstorm for all of the Northeast including towards the coast. But given climatological means during late October, snow will only fall in certain locations well to the northwest. Precipitation will move northward as rain into Virginia and Maryland Friday night and move up into southern Pennsylvania also as rain. Evaporational cooling will begin as 2m temperatures fall to near dewpoint values late Friday night changing over to snow for southern Pennsylvania particularily for elevations above 800ft with a rain/snow mix in the valleys.

As the low begins to intensify further, a deformation axis will likely form well to the west of the center of circulation. The placement of this axis is key to the snow accumulation region as it will bring cold air down the surface in the form of dynamic cooling. Given the low track this axis is likely to form in eastern Pennsylvania up through central New England. Saturday will feature well below normal highs withs highs not reaching 40 as far south as Washington DC. Precipitation will intensify during the day. Ground temperatures initially in the 40s and marginal boundary layer temperatures will keep the highest accumulations in the higher elevations with several inches possible above 200ft (perhaps up to 12in as far south as South Mountain, Pennsylvania). Elsewhere valley locations can also expect some light snow accumulation as far south as northern Maryland. For the I-95 corridor, a mix of rain and snow is likely with no accumulation. Snow accumulations up through New England are likely 4-7in for the valleys and 8-14in for the higher elevations. I could even envision higher amounts given the strength of the deformation axis. Total QPF printout from guidance such as the ECMWF and GEFS suggest 1.0in-2.0in across the entire Northeast.

Most of the snow will fall during the day Saturday. If timing were a bit more favorable such as Saturday night, this would have been a potentially record breaking, rare October snow event.

Given the high leaf foliage in some areas, the combination of wet snow will cause major tree damage in some locations especially in eastern Pennsylvania. Power outages are possible. Snow ratios will be near 6/7:1 with rates up to 0.5in/hr at times. Given the heavier snow rates at times, even areas with boundary layer temperatures at 34-35F may see a quick accumulation.

I want to raise a few critical points...

1) Current ground temperatures really have little to do with snow accumulation when rates fall above 0.5in/hr. Snow can accumulate even on roads. The sun angle in late October is like mid February and has little impact. Combine this with marginal temperatures, cloud cover, and heavy snow rates this will cause snow to accumulate very easily after the initial lighter snow.

2) The biggest concern is the trees which I have been hyping for the last 24hrs. Snow accumulations possibly over 10in in some areas of south-central Pennsylvania up through New England could bring devastation to trees. The heaviness of the wet snow on foliage is a disaster. And looking a records, this has never happened before in many areas!

3) I-95 is a tough forecast and is dependent on exact low track. But given the dynamics of this storm which may cause even thundersnow, the big cities should all change to snow at some point.

4) Given the time of year, water temperatures are very warm and the temperature gradient and the natural baroclinicity along the coast will cause the storm to rapidly undergo bombogenesis with very unusual mesoscale features. This will cause some areas to see rapidly high QPF totals.

Selected City Accumulations for the Northeast...
Hagerstown, MD- Rain/snow then heavy snow. Accumulations 5-12in
Baltimore, MD- Rain changing to snow. Accumulations up to 4in especially the higher hills.
Salisbury, MD- Mostly rain with a trace of snow
Pittsburgh, PA- Rain/snow then snow. Accumulations 2-4in
State College PA- Moderate snow. 5-7in
Williamsport, PA- Heavy snow. Accumulations 5-10in
Altoona, PA- Moderate snow. Accumulations 5-7in
Harrisburg, PA- Heavy snow. Snow accumulations 6-14in
Lancaster, PA- Heavy snow. Snow accumulations 6-13in
Philadelphia, PA- Rain/snow changing to snow. Accumulations 1-3in+
Allentown, PA- Heavy snow. Snow accumulations 6-14in
Scranton, PA- Heavy snow. Snow accumulations 6-12in
Washington, DC- Rain changing to rain/snow. Spotty 1-3in accumulations are possible
Wilmington, DE- Rain changing to rain/snow. Spotty 1-4in accumulations are possible
Dover, DE- Rain changing to rain/snow with trace accumulations
Trenton, NJ- Rain/snow changing to snow. Accumulations 2-4in
New York City, NY- Rain/snow changing to snow. Accumulations 1-6in depending on location.
Poughkeepsie, NY- Heavy snow. Accumulations 5-10in
Binghamton, NY- Light snow. Accumulations 3-6in
Ithaca, NY- Light snow. Accumulations 2-4in
Albany, NY-Moderate snow. Accumulations 4-8in
Hartford, CT- Rain/snow changing to heavy snow. Accumulations 4-7in
Concord, NH- Heavy snow. Accumulations 5-10in
Providence, RI- Rain changing to rain/snow. Spotty 1-3in accumulations
Worcester, MA- Heavy snow. Snow accumulations 6-13in
Boston, MA- Rain/snow with spotty accumulations 1-3in
Nantucket, MA- Heavy rain and high winds up to 60mph
Hyannis, MA- Heavy rain and gale force winds in excess of 60mph
Portland, ME- Heavy snow. Accumulations 4-9in
Bangor, ME- Heavy snow. Accumulations 6-12in
"Subject to Change"

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Winds picked up here about 10:45AM then the precip. started at about 11:15AM first alittle rain, at 40F then quickly to a wet snow. Temp. down to 34F in the matter of minutes, winds NE 10-15mph. with some higher gusts. Snow just beginning to stick on some surfaces Baro. down to 30.01"F. LT Stamford CT.
Member Since: January 31, 2009 Posts: 0 Comments: 8010
The light breeze that's beginning right now could actually help get some of the snow off these trees. Hopefully it doesn't get too strong though.
Member Since: August 5, 2010 Posts: 0 Comments: 588
Good morning everyone. I've received around 2" of snow so far north of Harrisburg and lost my power briefly.
Branches look heavily weighed down already and we've got at least 4 more inches to go, so this isn't looking too good.
Member Since: August 5, 2010 Posts: 0 Comments: 588
back to weather, the roads are covered here and some of the trees by my apartment are looking extremely stressed.

good thing I moved my Blazer.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
Well by virtue of their being 7-1, likely 8-1 after today and having a chance of being 10-1 headed to Madison for the season finale, and the fact that they sell tickets for the Florida bowls, they're already pretty much guaranteed a January 2nd (there are NO bowl games on Jan 1st this year because it falls on a Sunday) Bowl game in Florida.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
back to rain
Member Since: December 25, 2005 Posts: 0 Comments: 1744
Snowing moderately now, sticking on surfaces...this is crazy. This doesn't happen in October in NYC. We haven't even had a frost yet...
Member Since: January 20, 2009 Posts: 0 Comments: 1521
Quoting weathergeek5:


Keeps on going back and forth between sleet and rain


Same here, major battlefield between rain and snow, sleet getting into everything.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
Quoting PalmyraPunishment:


Yeah, I would agree with that assessment of the conference as a whole. Sparty is clearly the class of the conference and after that you have Wisconsin/Nebraska/PSU and the order that those three teams end up could be shuffled weekly because they all have weaknesses and strengths over each other, and then after that it's Michigan and a big drop to the rest.

I don't even think PSU should be ranked, much less 19th, but whatever, that's out of my control.


I think Sparty and Wisconsin are very good, but not on the same level as the big schools of the SEC or Big 12. Nebraska is next and Michigan and PU are below them. PU has a good defense, but like we saw in the Alabama game they are not close to being a New Years Day bowl, but with the tie-ins you never know these days
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Quoting CapeCoralStorm:
hard rain with some frozen precip in new castle,de


Keeps on going back and forth between sleet and rain
Member Since: December 25, 2005 Posts: 0 Comments: 1744
2" on the ground and still the same intensity of snow. my road is covered, but it has zero traffic on it.
Temp 32.6F dewpt 31.8F

I stepped outside and heard a tree crack in the woods. This is not going to be pretty if we get 6-8 hours of this snow. I have trees already bending down. Not going to be pretty
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Quoting TheRasberryPatch:


With the weather you better have a good running game because throwing the ball will be mostly non-existant. And you better hold onto the ball. Is it me or is most of the Big Ten mediocre at best?


Yeah, I would agree with that assessment of the conference as a whole. Sparty is clearly the class of the conference and after that you have Wisconsin/Nebraska/PSU and the order that those three teams end up could be shuffled weekly because they all have weaknesses and strengths over each other, and then after that it's Michigan and a big drop to the rest.

I don't even think PSU should be ranked, much less 19th, but whatever, that's out of my control.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
Has become primarily snow in Brooklyn now with the temperature down to 36 degrees.
Member Since: January 20, 2009 Posts: 0 Comments: 1521
Nothing going on here yet in springfield, looks like there's some nice virga way ahead of the storm so hopefully when the snow arrives it will just start falling!
Member Since: February 23, 2010 Posts: 0 Comments: 685
214. RkTec
Photobucket
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Quoting PalmyraPunishment:
Snow has become heavy in the last 20 minutes or so, ground is now completely white, roads are covering up. Just saw footage from Happy Valley, I wish I were there :(

Silas Redd's been experiencing "stingers" this week. With the snow, they'll likely abandon the already anemic passing game completely and hand him the rock. Hopefully he holds up.


With the weather you better have a good running game because throwing the ball will be mostly non-existant. And you better hold onto the ball. Is it me or is most of the Big Ten mediocre at best?
Member Since: January 26, 2007 Posts: 72 Comments: 6276
212. RkTec
11 a.m. obs for Emmaus, PA - Lehigh County
Temp: 33
DP: 33
Moderate snow
1.75" on snowboard
0.75" on paved surfaces, mainly secondary roads snow/slush covered
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Snow has become heavy in the last 20 minutes or so, ground is now completely white, roads are covering up. Just saw footage from Happy Valley, I wish I were there :(

Silas Redd's been experiencing "stingers" this week. With the snow, they'll likely abandon the already anemic passing game completely and hand him the rock. Hopefully he holds up.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
About an inch of snow on the cars and a half inch on the parking lot at the moment. A light coating on the road ways but it is coming down in very heavy flakes. Walking out to my car heard a few branches popping off like firecrackers
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Light snow just started in Warwick, NY
Member Since: January 10, 2009 Posts: 0 Comments: 92
Quoting PhillySnow:


I'll hope for your power to stay on, then!

We're all snow hours before predicted. It's sticking to trees and a bit now to the road. I think your upgrade for Philadelphia is correct, Blizz!



WHAT still very wet here right across the Delaware.

35F wintry mix here.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
hard rain with some frozen precip in new castle,de
Member Since: May 16, 2009 Posts: 0 Comments: 213
Snow mixed with rain a few minutes ago in Holmdel NJ on Jersey shore (Monmouth County) Amazing
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Very light snow starting here in Western Sullivan County Ny/ Pa Border.
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Quoting originalLT:
PhillySnow, thanks for asking, the answer is no, as of now, we have an electrition coming by later today. We did get 2 space heaters from a friend, and they are helping alot. Hopefully, he'll get it fixed--seems to be an electrical problem, not a problem with the furnace itself(I hope!).


I'll hope for your power to stay on, then!

We're all snow hours before predicted. It's sticking to trees and a bit now to the road. I think your upgrade for Philadelphia is correct, Blizz!

Member Since: December 18, 2009 Posts: 0 Comments: 1270
There's around 3-4 inches on the ground, with about six inches on the cars and the clothes line beams. Many trees have already come down, and one large tree split off and is now lying in our garden. Amounts of just under 3 inches in the valley. It will surely be an interesting PSU game today. They had to change the parking around and many will have to take a shuttle to the stadium.
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I think I got this photo posting thing figured out now. Try, try again! :-)

Photo taken at 10:30 a.m., Harrisburg (Swatara Twp), PA
Member Since: December 25, 2002 Posts: 0 Comments: 88
Philadelphia Art Museum reporting all snow!
Member Since: August 28, 2008 Posts: 79 Comments: 3713
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Member Since: December 25, 2002 Posts: 0 Comments: 88
The temp was 43 when I awoke at 830AM. It is now down to 37...I'm thinking we might have complete changeover long before predicted. Is that likely, Blizz?
Member Since: January 20, 2009 Posts: 0 Comments: 1521
Sleet coating on several surfaces.
Member Since: August 28, 2008 Posts: 79 Comments: 3713
S+ here. this is a great rate!
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Hello everyone :) Haven't checked in for a while, but I figure today is an appropriate time to return. It's been rain all morning in New York, but, regardless of what it shows on radar, snow flakes have begun mixing in here in Brooklyn. Long before they said they would. I'm assuming it'll go back to all rain most of the day, until nightfall, but it does make me wonder. More rain than snow, to be sure, but it's great to see the scattered flakes for the first time in many months.
Member Since: January 20, 2009 Posts: 0 Comments: 1521
LSV is for the lower Susquehanna valley in Pennsylvania.

Quoting TheRasberryPatch:
Blizz - are the oranges on the radar northeast of DC sleet or heavy snow?
the yellows have filled in over the area

Definitely snow when it moves up here. Probably sleet down there.
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Latest discussion talks about deformation occurring over Western PA. What does that mean in terms of weather?
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Snow has kind of let up here in Camp Hill for the moment. Grass is white, not quite past "dusting" category, but I am surprised at how quickly it began laying.
Member Since: January 31, 2007 Posts: 9 Comments: 2250
Quoting pittsburghnurse:
Just saying this was an under reported event for the local area. Did the storm move west?


I agree they where still reporting t-1inch last night for most of the local area, can't wait to see what they say tonight
Member Since: August 23, 2008 Posts: 0 Comments: 140
Quoting originalLT:
Be careful MM, driving in those conditions and going up in altitude can be very dangerous. Maybe you should hold off till Sunday.


I'll be careful, but no way for Sunday. I'm getting there today, whatever it takes!
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Just saying this was an under reported event for the local area. Did the storm move west?
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Not too much snow here yet in Confluence Pa (1335 ft), although a heavy band is approaching us. I took some photos this morning. As you can see many of the trees still have leaves



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Quoting wxgeek723:


How'd you end up in Moorestown? That's about 12 miles away from me.


I posted below how I ended up here. I'm waiting for my wife to get out of work around noon at a bank she's working at nearby. Then we're heading right from here to the gated community of Arrowhead Lakes, township of Pocono Lake around 1700ft. I'll be careful. I've driven in countless heavy snowstorms. I used to be a cross-country truck driver, 18-wheeler where driving in heavy snow was just a part of every day life. I've got 4-wheel drive, I'll be alright! My wife on the other hand, she wouldn't be alright in her 2-wheel drive Honda.
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Not sure if this will help the trees, but some breeze blowing the tops of the trees. I was thinking this might help keep the snow accumulating on the tops of the trees.

As much as I don't care for TWC, I was watching this AM and they were saying it's not if we lose power it is be prepared because it's when it will happen
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Quoting CapeCoralStorm:
Spoke to soon. Large snow flakes mixing in with the rain now in New Castle,De


Just saw that. I was about to report it on here
Member Since: December 25, 2005 Posts: 0 Comments: 1744
Blizz - are the oranges on the radar northeast of DC sleet or heavy snow?
the yellows have filled in over the area
Member Since: January 26, 2007 Posts: 72 Comments: 6276
Spoke to soon. Large snow flakes mixing in with the rain now in New Castle,De
Member Since: May 16, 2009 Posts: 0 Comments: 213
Quoting weatherman321:
Greensburg, PA - 3-4inches have fallen, grass covered, my road in town is covered(penndot must have watch local weather haha) some trees are starting to get weighed down, especially my neighbors tree, which is right in the power lines... Blizz how much longer should this band be over us??


We've still got a pretty heavy rate West of you here in Pitt. No signs of slowing down but maybe some warming mixing in.
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Saw a Facebook picture from Shippensburg, roads are covered!!!
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