Unprecedented, Destructive October Snowstorm!

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

Share this Blog
5
+

"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"

Reader Comments

Comments will take a few seconds to appear.

Post Your Comments

Please sign in to post comments.

or Join

Not only will you be able to leave comments on this blog, but you'll also have the ability to upload and share your photos in our Wunder Photos section.

Display: 0, 50, 100, 200 Sort: Newest First - Order Posted

Viewing: 380 - 330

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10Blog Index

Pure snow at last!
Member Since: Posts: Comments:
Here is a link to a video I made today.

Watch it in 720P and full screen. You can really see the snow fly.

Link

Member Since: Posts: Comments:
Quoting photonchaser:

Already? We are yet to see any thing in Portland, not even any rain. Maybe we will see higher amounts than forcasted!


yeah the grass is already completely covered and its beginning to stick to the roads. Started out here as a mix and then quickly turned over to all snow. Temp just plummeted here. Literally dropping almost 5 degrees in a couple of hours. I believe it is 34 here now.
Member Since: Posts: Comments:


Croton, NY. Just north of Ossining. 465ft elevation, 2 miles east of the Hudson River.


And we're what maybe halfway through. That's one wicked band setting up!



Member Since: Posts: Comments:
...Still raining...

.____.
Member Since: Posts: Comments:
Quoting Sockets:
Wow, all snow now here in Kittery, ME...much sooner than was forecasted. Already accumulating on the ground. We are going to get some impressive snow totals from this.

Already? We are yet to see any thing in Portland, not even any rain. Maybe we will see higher amounts than forcasted!
Member Since: Posts: Comments:
Coming down good here.

Current conditions

heavy snow 5" on the ground. Vis about 100 yards.
Temp steady @ 29F
Light breeze... not enough to call it wind.


Pic from a bit ago.

Hosted on Fotki
Member Since: Posts: Comments:
Mason - refresh my memory...when do you report on final snow accumulation? Also, I checked on my outer cylinder @ 230 and it was completely covered over at the top. Not filled to the top, just coverd over from the wet snow sticking together. I guess I won't be able to report on the water content, unless you have some other way I can use
Member Since: January 26, 2007 Posts: 72 Comments: 6255
still light snow...I measured 5.0" @ 230pm. I would guess I have gotten close to another 2". I will check once the snow has stopped.
Campbelltown, PA just east of Hershey

I was out for 2 hours knocking the snow from all my trees and bushes. what a workout. and every piece of clothing was soaked. My gloves were the wettest
Member Since: January 26, 2007 Posts: 72 Comments: 6255
Wow, all snow now here in Kittery, ME...much sooner than was forecasted. Already accumulating on the ground. We are going to get some impressive snow totals from this.
Member Since: Posts: Comments:
What may be last significant snow band was on radar heading this way, now here in NW Philly. Some wind. This was my birthday...aghhhh 62 today, but in all my years the first time it has snowed on my birthday. Quite a present.
Member Since: Posts: Comments:
4.2" offically here in cashtown.
Member Since: November 5, 2008 Posts: 0 Comments: 1139
368. Gaara
CL&P and UI reporting a combined 100K power outages in CT.. All this well before the peak winds. Thankfully, the brief bit of mixing we had managed to knock a lot of the snow off of the trees.
Member Since: Posts: Comments:
Accumulations are over for LSV for most areas. Crazy that we got these snow accumulations in the day and yet temperatures still have yet to hit 32F this year in Harrisburg! So what are some totals? Keep in mind compaction will reduce your total and the snow is likely melting from the bottom on the ground.
Member Since: December 14, 2007 Posts: 282 Comments: 15099
Seems to be winding down here in HBG.
Member Since: January 29, 2011 Posts: 0 Comments: 53
Still snowing in Harrisburg but the intensity has let up considerably. Actually pretty light now. Just finished digging out the cars...looks like 5" to 6" so far.
Member Since: December 25, 2002 Posts: 0 Comments: 88
Just getting started here in Kittery, Maine. Currently getting a rain snow mix but the temp is falling fast. If this keeps up we are gonna be all snow much sooner than was anticipated.
Member Since: Posts: Comments:
Hurricane Force Wind Warning just off the coast near me!
Member Since: Posts: Comments:
Snow here finally.
Member Since: December 25, 2005 Posts: 0 Comments: 1744
361. bwi
And sure enough, HPC shows a 999mb low just off Ocean City!
Member Since: September 4, 2007 Posts: 0 Comments: 1381
360. bwi
Starting to get some nice snow/slush in Maryland suburbs NE of DC. A little white on the cars and rooftops. Looks like a strong band about 50 miles to our west, oriented from SSW to ENE along the northern Montgomery and Howard county lines. Maybe that will rotate trough. Temp still 35 though.

On visible satellite, sort of looks like an "eye" off Ocean City MD.
Member Since: September 4, 2007 Posts: 0 Comments: 1381
There...back on line, finally! One of our mini-power outages managed to somehow zap the WIFI router and wipe the configuration. Had to start from scratch, set up the router, and then reconfigure every wireless device in the house to access the router. What a pain...

Still heavy, steady snow here in Harrisburg. Probably 4-5 inches and showing no signs of letting up.
Member Since: December 25, 2002 Posts: 0 Comments: 88
Quoting originalLT:
Good to see you "check in" Pcroton. LT


Hi LT it's been some time.

Great event. You have some time before more cold air filters in for you there. It's on the way this evening I would suspect.

I'm not liking the now freezing of the heavy wet snow on the branches along with the prospect of winds picking up to the 45+ range later as the low winds up and pulls away.

Not a good scenario for us at all. Too many trees with foliage left.

What a terrible leaf season. Half gone. Whats left is half washed out yellows/reds/browns and half GREEN if you can believe it.

Member Since: Posts: Comments:
If you stand outside branches falling is fairly constant...about every 20 seconds or so you hear a creak creak crack CRASH in the woods lol.

Every so often we lose power for a moment or two.






Member Since: Posts: Comments:
Quoting originalLT:
We have about 3-4" of very wet slushy snow, Temp. has been holding about 33F wind generally N-NE 10-15mph. Baro 29.85F Many large branches have broken off, wires hanging over roads, lights have flickered and many in my neighborhood are without power--afraid mine could go soon. No phone service, have to use the cell phone. (Got my heat fixed though!) As long as we have power, it will work. LT Stamford CT.


That's bad news LT. First your heat, now your power. We're fortunate to have our wires underground. Hope you fair ok. I think we've not even hit the halfway point yet in terms of accumulation.
Member Since: Posts: Comments:
Good to see you "check in" Pcroton. LT
Member Since: January 31, 2009 Posts: 0 Comments: 7451
We have about 3-4" of very wet slushy snow, Temp. has been holding about 33F wind generally N-NE 10-15mph. Baro 29.85F Many large branches have broken off, wires hanging over roads, lights have flickered and many in my neighborhood are without power--afraid mine could go soon. No phone service, have to use the cell phone. (Got my heat fixed though!) As long as we have power, it will work. LT Stamford CT.
Member Since: January 31, 2009 Posts: 0 Comments: 7451
First plow just went by.
Member Since: Posts: Comments:
Hey Goofy good to "see" ya.

Currently approaching 6".

Member Since: Posts: Comments:
Snow type changed from big wet flakes to drier finer flakes and more numerous now.

The low is beginning to wind up. Winds shifting more northerly and colder as a result.

Seems the dry slot is done with it's northward progression and the north-south banding is beginning to set up.

Looks like a go for 12"+ for me up here. Just north of Ossining.

Member Since: Posts: Comments:
40 N, 74 W

Afternoon: at 1300 some sleet here for a while, more than an inch of rain. Barometer dropped from 1026 mb at midnight to 1007 and still dropping. be interesting to see what the backside of the storm has in store for us. Winds, gusting to 34 mph on the beach, out of the NE, temp at 40 F.

Nice shots P
Member Since: Posts: Comments:
Cannot believe how heavy it was just snowing!!!!!! Still have power here in Fishing Creek Valley...which is hard to believe too!!!
Member Since: January 29, 2011 Posts: 0 Comments: 53
last few radar scans show dry slot slowlly sorta filling in a bit.....winds definitely starting to pick up here on long island, seein some leaves rustling around...still a heavy rain snow mix here on long island...just waiting for that sun to go down.....wish this started at night....
Member Since: Posts: Comments:
I feel like this is the kind of storm you read about happening in say the 1800s and thinking "How the heck can it snow like that in October? Oh well, doubt it's anything I'll ever see."

Yet lo and behold...
Member Since: Posts: Comments:
first post here... I like the reports. I am on the North Shore of western suffolk county on long Island. Currently reporting rain/snow mix. 2-6 inches here with 6-10 in city? I saw a dry slot further south in eastern pa, will this affect totals. Thanks guys.
Member Since: Posts: Comments:
Looks, on radar, like this thing is beginning to turn into the beast some were speaking of. We have 2.5" compacted inches of snow on the ground which has made for a slushy mess. I'm guessing at least an inch more than that has fallen. They just upped our totals, as I expected they'd have to at some point, from 2-4" to 6-10." I'm still in total awe of such an impressive October snowfall.
Member Since: Posts: Comments:
I'm seeing my heaviest snow yet. It's probably well over an inch per hour.
Member Since: Posts: Comments:
Dry slot....this is rather anticlimactic
Member Since: Posts: Comments:
About an inch of slushy snow/sleet here in northwest phila. Roads wet to slushy. Small to moderate limbs down in some areas, but not widespread. Winds a mixed blessing, stressing trees, but also jostling trees just enough to dislodge some of the snow weight. Precip was moderate sleet with snow but now slacked off to near nothing.
Member Since: Posts: Comments:
About an inch of slushy snow/sleet here in northwest phila. Roads wet to slushy. Small to moderate limbs down in some areas, but not widespread. Winds a mixed blessing, stressing trees, but also jostling trees just enough to dislodge some of the snow weight. Precip was moderate sleet with snow but now slacked off to near nothing.
Member Since: Posts: Comments:
We have about 4 inches on the ground in Lawnton, just E of Harrisburg and it is coming down at a real heavy rate. It reminds me of the white outs they have near Buffalo. If this keeps up of another 4 hours, we will end up with about 12 to 14 inches of snow. I good snow for making snow men or snow forts. I wasn't prepaired because I couldn't find my boots or hat and gloves. Finally found the boots in the trunck of the car.

Member Since: April 18, 2011 Posts: 0 Comments: 31
339. Gaara
Smaller flakes and some mixing now in Coastal CT. First power flicker, too. Great.
Member Since: Posts: Comments:
crazzzzzzzzzy here.
Member Since: December 15, 2007 Posts: 19 Comments: 987
Quoting danielb1023:
Pcroton.....we already crushed previous October snow records here so the rest is gravy. We are playing with house money now!!!!!!!!


This is true...even if it ended now it'd be an incredible event.

Whether or not it goes into incredible territory depends on the band's tilting and where it sets up.

Where I am usually the dry slot gets close but then stalls...and as the band tilts to it's north/south orientation I am left in snow the whole time.

We will see how it pans out. It'll be the difference between a 6-8" storm and a 12-18" storms. Either or for a couple of places.
Member Since: Posts: Comments:
sleet falling now
Member Since: December 25, 2005 Posts: 0 Comments: 1744
Snow in annandale, mostly rain on Capitol Hill. First snow/slushball of the year made and thrown. Target acquired and destroyed.
Member Since: Posts: Comments:
Still coming down as snow here in East Petersburg, PA. (about 7 miles N of Lancaster). Had some sleet about 30 minutes ago, then back to moderate snow. About 2.5 inches on the ground, roads are slushy. Not looking like the 10+ predicted here though...
Member Since: Posts: Comments:
Trees on their way out...

Member Since: Posts: Comments:
Quoting CapeCoralStorm:
Anyone have any thoughts on northern delaware? It just started raining again here. 0 snow outside of a couple large flakes earlier..

Are we going to get snow, or are we up the river....


You've been dry slotted at the moment...expect some rain changing to snow when the sun goes down.....could see a slushy coating/2" depending on where you are...there is definitely a back side yet to sweep through....patience....
Member Since: Posts: Comments:
Anyone have any thoughts on northern delaware? It just started raining again here. 0 snow outside of a couple large flakes earlier..

Are we going to get snow, or are we up the river....
Member Since: Posts: Comments:
Pcroton.....we already crushed previous October snow records here so the rest is gravy. We are playing with house money now!!!!!!!!
Member Since: September 2, 2010 Posts: 0 Comments: 256

Viewing: 380 - 330

Page: 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10Blog Index

Top of Page

About Blizzard92

Cornell University- Atmospheric Sciences Undergrad; Research Assist.- Onset of Spring Indices Toolbox; Interests- Small spatial scale climatolology

Local Weather

Scattered Clouds
69 °F
Scattered Clouds

Blizzard92's Recent Photos

Personal Weather Stations

Linglestown, PA
Elevation: 520 ft
Temperature: 24.2 °F
Dew Point: 15.2 °F
Humidity: 68%
Wind: Calm
Wind Gust: 9.0 mph
Updated: 10:37 AM EST on January 18, 2014

About Personal Weather Stations