Colder Unsettled Weather Ahead...

By: Zachary Labe , 4:40 PM GMT on December 27, 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"


"Soil Moisture Anomalies and 5-day Precipitation Amounts from Hydro Prediction Center"


"Severe Weather Outlooks from Storm Prediction Center Days 1, 2, and 3"


"12hr Estimated Precipitation"


"Forecast Max Temperatures"


"Forecast Min Temperature"


"Forecast Weather at 2pm"


"Current Storm Reports"


"Fire Outlooks from Storm Prediction Center Days 1, 2, and 3"

(All maps courtesy of NOAA and Penn State Meteo.)

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

"Severe Weather Links"
-Atmospheric Soundings Skewt T charts...Link
-SPC Mesoscale Analysis Pages...Link
-Public Spotter Reports for State College NWS...Link
-Severe Weather Model Forecast indices...Link
-Severe Weather Parameter Definitions...Link

"Flooding Links"
-Automated Pennsylvania Rainfall Recording Stations...Link
-Flash Flooding Guidance...Link
-HPC Forecasts for Excessive Rainfall...Link
-Hydrology Predictions for Lakes, Rivers, and Streams...Link

Lower Susquehanna Valley Doppler...

(Courtesy of WGAL)

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

"10mi northeast of Harrisburg 2011-2012 winter statistics"
(Snow Stats)
Current Snow Cover- 0.0in
Monthly Total (October)- 5.5in
Monthly Total (November)- 0.0in
Monthly Total (December)- 0.4in
Seasonal Total- 5.9in
Winter Weather Advisories- 1
Winter Storm Warnings- 1
Ice Storm Warnings- 0
Blizzard Warnings- 0
Freezing Rain Advisories- 0
Winter Storm Watches- 1

(Temperature Stats)
Lowest High Temperature- 31F
Lowest Low Temperature- 17F
Wind Chill Advisories- 0
Wind Chill Warnings- 0

(Snow Storms Stats)
Historic October Nor'easter - October 29 - 5.5in of wet snow
322 Lake Effect Snow Band - December 17 - 0.3in of wet snow
Weak Clipper - December 29 - 0.1in of snow

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142. TheRasberryPatch
8:53 PM GMT on December 31, 2011
Thank You Blizz. so nice to have your expertise available.

Hopefully, once I get over the mountain and that tunnel just east of Somerset it won't be bad.

On my way out here on Wednesday I hit a lot of snow showers from Carlisle through Pittsburgh. There was snow on the ground from Somerset all the way to Niles. The snow is gone with temps getting into the upper 40's yesterday. Yesterday we had 0.31" of rain. Today is pretty nice with highs in the low 40's.
Member Since: January 26, 2007 Posts: 72 Comments: 6233
141. Zachary Labe
7:42 PM GMT on December 31, 2011
Quoting HeavySnow:
Disgustingly, brutally warm weather here in DC. I'm on Cap Hill now and it is shorts weather for me. Gross. How far out is that 10 inches for KMDT Blizz? I need sunblock. Ski Liberty needs, hmmm, where do I start. Well, they have booze and the golf course is still probably open. They are hurting worse than all of us.

The 10in is an accretion of several smaller snow events over the longer range around the day 10-16 range.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
140. HeavySnow
6:16 PM GMT on December 31, 2011
Disgustingly, brutally warm weather here in DC. I'm on Cap Hill now and it is shorts weather for me. Gross. How far out is that 10 inches for KMDT Blizz? I need sunblock. Ski Liberty needs, hmmm, where do I start. Well, they have booze and the golf course is still probably open. They are hurting worse than all of us.
Member Since: July 7, 2004 Posts: 18 Comments: 2989
139. PhillySnow
5:56 PM GMT on December 31, 2011
56F here and a beautiful spring day yet again. It's amazing how green our grass is. I'm glad to hear there's some cold air coming, and possibly even with precipitation for some folk!
Member Since: December 18, 2009 Posts: 0 Comments: 1210
138. bwi
5:56 PM GMT on December 31, 2011
62 degrees at DCA -- 57 here in close-in MD suburbs.
Member Since: September 4, 2007 Posts: 0 Comments: 1356
136. Zachary Labe
5:32 PM GMT on December 31, 2011
12z GFS is best run I have seen in a while... Actually brings the cold air and precipitation together. Almost 10in of snow verbatim on the GFS for KMDT in the long range.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
135. Zachary Labe
5:18 PM GMT on December 31, 2011
Quoting TheRasberryPatch:
Thank you so much for your forecast and advice, Blizz. It is very much appreciated.
I sort of thought conditions would be bad with the winds they were predicting. This will be the first LES here in Niles, MI. Pretty incredible and figures it almost always occurs when I am traveling back.

Do you think conditions will be bad throughout the PA turnpike? or just the snowbelt regions? I noticed they don't have much for LSV forecast.

Thank you for your thoughts LT. I have done this drive in the past white knuckled and it isn't fun.

The Laurels could be pretty bad on the turnpike between Latrobe and Bedford. Conditions could be near whiteout by late Sunday night into Monday around Somerset. A few squalls are likely to make it into the LSV, but predicting those will be impossible to track where until a few hours before (maybe 322 band). Winds along the turnpike may be howling upwards of 55mph above 1500ft Sunday night.

I am working on a new blog detailing the lake effect and cold outbreak. It will probably be posted Sunday morning or so.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
134. TheRasberryPatch
5:07 PM GMT on December 31, 2011
Thank you so much for your forecast and advice, Blizz. It is very much appreciated.
I sort of thought conditions would be bad with the winds they were predicting. This will be the first LES here in Niles, MI. Pretty incredible and figures it almost always occurs when I am traveling back.

Do you think conditions will be bad throughout the PA turnpike? or just the snowbelt regions? I noticed they don't have much for LSV forecast.

Thank you for your thoughts LT. I have done this drive in the past white knuckled and it isn't fun.
Member Since: January 26, 2007 Posts: 72 Comments: 6233
133. Zachary Labe
4:35 PM GMT on December 31, 2011
Quoting TheRasberryPatch:
Good morning Blizz

I am up here in Niles, MI just north of South Bend. They have Winter Storm Watch for Sunday evening into Tuesday morning. Heavy snow is predicted from the LES. Any thoughts? I am travelling supposedly Monday AM, but I am afraid it will be bad road conditions all day Monday from the Indiania Toll Rd into Ohio Turnpike and through to Somerset. I realize LES isn't easy to predict. The winds are supposed to be strong with temps on Monday in low 20's. I just am concerned the road conditions with snow, blowing and drifting snow. Not fun. I may just leave on Sunday afternoon with temps closer to freezing.

I would advise leaving as early as possible. Conditions are going to rapidly deteriorate by Sunday evening through Tuesday night with blizzard conditions across all of the snow belt regions. It is pretty much guaranteed for several severe bands isolated through the entire area of interstate. Winds will be nearing 45mph, so blowing snow will be a major problem with whiteout conditions.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
132. originalLT
4:16 PM GMT on December 31, 2011
TRP, I hope Blizz can give you some idea of how bad the LES will be for you. In any event, be careful on the road. Safe trip back. LT
Member Since: January 31, 2009 Posts: 0 Comments: 7058
131. TheRasberryPatch
4:13 PM GMT on December 31, 2011
Good morning Blizz

I am up here in Niles, MI just north of South Bend. They have Winter Storm Watch for Sunday evening into Tuesday morning. Heavy snow is predicted from the LES. Any thoughts? I am travelling supposedly Monday AM, but I am afraid it will be bad road conditions all day Monday from the Indiania Toll Rd into Ohio Turnpike and through to Somerset. I realize LES isn't easy to predict. The winds are supposed to be strong with temps on Monday in low 20's. I just am concerned the road conditions with snow, blowing and drifting snow. Not fun. I may just leave on Sunday afternoon with temps closer to freezing.
Member Since: January 26, 2007 Posts: 72 Comments: 6233
130. Zachary Labe
3:58 PM GMT on December 31, 2011
Quoting Mason803:
temp has jumped to 54f already this morning. i think i might have the warmest temp in the state. just lovely

Up to 51F here currently; feels extremely warm outside today!
Member Since: December 14, 2007 Posts: 278 Comments: 15045
129. Mason803
3:30 PM GMT on December 31, 2011
temp has jumped to 54f already this morning. i think i might have the warmest temp in the state. just lovely
Member Since: November 5, 2008 Posts: 0 Comments: 1139
128. Zachary Labe
2:46 PM GMT on December 31, 2011
Even the lake effect event does not look quite as good as it once did; the arctic front lags a bit on Monday keeping the flow west-southwest for a time. That flow is horrible for Pennsylvania for lake effect, but does give a nice band up through Buffalo and Watertown, NY.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
127. weatherman321
5:34 AM GMT on December 31, 2011
Excited for this lake effect event, for early next week.
Currently were forecast to receive c-2in on monday, 2-4in monday night and c-1in for tuesday.. Pattern change still don't look good for january...maybe Feb? but anyways I'll take what ever i can get at this point.
Member Since: August 23, 2008 Posts: 0 Comments: 140
126. Zachary Labe
4:14 AM GMT on December 31, 2011
Quoting originalLT:
Blizz, just looked at your charts from your posts #37 and #41, very interesting--big difference in accumulation from Philly to Harrisburg. For 2010-2011 winter , Harrisburg looked to be about 5" less than "average", if I'm reading it right.

You are 100% correct; totally different setup last year which was very conducive to eastern snowfalls. We just unfortunately missed out here to the west. You are reading that chart correctly, but it is based on Middletown Airport (KMDT). Their average is 4in lower than the actual city of Harrisburg. And then up here along the mountain you can add about another 4in to the average. I would say here in Linglestown, I am around 38in for a seasonal average. Middletown is along the river and a good bit south of here including the city of Harrisburg. It always makes me angry that our records are based at a location so displaced from the actual city which holds the record title.

I hope that made sense, lol.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
125. listenerVT
4:04 AM GMT on December 31, 2011
Got home from work just past 8pm last night and it was 2F here. We saw -3F on the porch thermometer. Today the birds were at the feeders in full force, and it warmed to 17F by the time I had to leave to pick up my Granddaughter. I'd say we got another inch or so of snow. Tonight, though, the temps are on the rise (about 24F here now). We're looking at freezing rain overnight and until sometime after I drive to work in the morning.
Member Since: July 11, 2007 Posts: 0 Comments: 5401
124. originalLT
3:49 AM GMT on December 31, 2011
Blizz, just looked at your charts from your posts #37 and #41, very interesting--big difference in accumulation from Philly to Harrisburg. For 2010-2011 winter , Harrisburg looked to be about 5" less than "average", if I'm reading it right.
Member Since: January 31, 2009 Posts: 0 Comments: 7058
123. originalLT
3:41 AM GMT on December 31, 2011
Thanks Blizz, didn't realize that for you guys in the LSV, But you have to admit the set-up was better, more conducive to the possibility for snow for the NE than this year for sure, you happened to miss it last year I guess.
Member Since: January 31, 2009 Posts: 0 Comments: 7058
122. photonchaser
2:21 AM GMT on December 31, 2011
We got a short 15 minute burst of snow today which left a nice dusting on all the trees. At least it sort of looks like winter...for now.
Member Since: June 3, 2004 Posts: 1 Comments: 134
121. originalLT
12:53 AM GMT on December 31, 2011
And you are right, TheF1Man, that clipper has a nice "swirl" to it. I guess they are saying it's the positive NAO, and other things as Blizz has said, and no blocking over Greenland that's really hurting our chances for coastal storm developement, and the lack of a nice cold high pressure system over Eastern Canada to funnel down some nice cold North East winds.
Member Since: January 31, 2009 Posts: 0 Comments: 7058
120. Zachary Labe
12:50 AM GMT on December 31, 2011
Quoting TheF1Man:
Clipper actually looks pretty good on the radar. Any chance that the temperature will suddenly drop 30 degrees?! Played football with friends today, wore shorts and short-sleeves no problem. I don't ever remember being able to do that.

Blizz is this the opposite to last year where all of the cold air spilled out of the arctic and into the U.S. Now this year it's all bottled up?


Polar vortex over Alaska is killing us allowing Pacific air to flood the entire nation.

originalLT- Farther inland was a low snow year compared to the I-95 corridor last winter. We ended with nearly 10in below average here in Harrisburg. And we missed the heaviest snows during 09-10.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
119. originalLT
12:45 AM GMT on December 31, 2011
Nature does tend to even-out things over the long run. We've just had two very snowy winters in a row, not surprised if we get a horrible one(for snow that is) ,this winter season.
Member Since: January 31, 2009 Posts: 0 Comments: 7058
118. TheF1Man
12:24 AM GMT on December 31, 2011
Clipper actually looks pretty good on the radar. Any chance that the temperature will suddenly drop 30 degrees?! Played football with friends today, wore shorts and short-sleeves no problem. I don't ever remember being able to do that.

Blizz is this the opposite to last year where all of the cold air spilled out of the arctic and into the U.S. Now this year it's all bottled up?

Member Since: February 23, 2010 Posts: 0 Comments: 669
117. Zachary Labe
11:45 PM GMT on December 30, 2011
Quoting HeavySnow:


Any glimmer of hope on the horizon(or further)?

Winter of 2012-2013?

We can cross our fingers that a lake effect snow shower moves east of the mountains next week, although down there I doubt there is much chance. Looks like a warm spell is coming next weekend already. I predict this month will feature temperature mean anomalies of +3.0F for most areas.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
116. HeavySnow
11:43 PM GMT on December 30, 2011
Quoting Blizzard92:
You know the weather pattern is bad when an Alberta clipper brings rain as far north as the the US/Canadian border; what a depressing winter!


Any glimmer of hope on the horizon(or further)?

Winter of 2012-2013?
Member Since: July 7, 2004 Posts: 18 Comments: 2989
115. Zachary Labe
10:37 PM GMT on December 30, 2011
You know the weather pattern is bad when an Alberta clipper brings rain as far north as the the US/Canadian border; what a depressing winter!
Member Since: December 14, 2007 Posts: 278 Comments: 15045
114. Zachary Labe
8:49 PM GMT on December 30, 2011
Quoting MariettaMoon:
Blizz: I'm really shocked that there's no coastal cyclone development given how amplified the trough is early next week. It seems that since there is no Greenland/Iceland block, the trough is so progressive that it just sweeps right through giving a very small window of opportunity for coastal cyclogenesis. An area of low pressure does end up firing up well off the coast south/southeast of the Canadian Maritimes.

Also, the 980mb low over Quebec early next week is so large and strong that the wind effects are felt all the way down into the Carolinas, with strong west winds blowing well offshore not allowing south/east winds to blow from the Gulf Stream to the shore, inhibiting cyclogenesis there.

Am I right/wrong in my analysis of the situation?

Your analysis is completely accurate. The flow is definitely too progressive next week for the low pressure to move along the coast; had there been a blocking mechanism, perhaps things would be different. Latest 12z ECWMF strengthens the low about 300mi off the coast, but there really isn't any feature that should pull it back west.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
113. MariettaMoon
6:23 PM GMT on December 30, 2011
Blizz: I'm really shocked that there's no coastal cyclone development given how amplified the trough is early next week. It seems that since there is no Greenland/Iceland block, the trough is so progressive that it just sweeps right through giving a very small window of opportunity for coastal cyclogenesis. An area of low pressure does end up firing up well off the coast south/southeast of the Canadian Maritimes.

Also, the 980mb low over Quebec early next week is so large and strong that the wind effects are felt all the way down into the Carolinas, with strong west winds blowing well offshore not allowing south/east winds to blow from the Gulf Stream to the shore, inhibiting cyclogenesis there.

Am I right/wrong in my analysis of the situation?
Member Since: June 11, 2011 Posts: 36 Comments: 677
112. MariettaMoon
5:45 PM GMT on December 30, 2011
Quoting NEwxguy:
our non winter continues this weekend.Even the artic shot next week,isn't anything record breaking and will only last a couple of days.We only had a trace of snow in December so I went looking at past winters with light snowfall in December and most of them continued the this pattern,with some snowfall,but nothing major,a couple years rebounded to have normal snowfall totals,but a lot of others were below normal snowfall for the winter.


Wednesday morning, 01/04 forecast lows F and (daily records F in parenthesis)
Caribou: -4F (-27F)
Burlington: -2F (-27F)
Portland: 9F (-18F)
Concord: 0F (-23F)
Syracuse: 6F (-18F)
Albany: 7F (-15F)
Mount Pocono: 9F (-23F)
Boston: 14F (-4F)
New York: 19F (-3F)
Pittsburgh: 14F (-8F)
Harrisburg: 18F (3F)
Philadelphia: 20F (2F)
Baltimore: 17F (4F)
Washington: 22F (-3F)
Member Since: June 11, 2011 Posts: 36 Comments: 677
111. Zachary Labe
3:09 PM GMT on December 30, 2011
Well Middletown officially reported .1in yesterday. Looks like we don't leave skunked here in Harrisburg for December; a whopping .1in of snow officially, woah! And a wonderful .4in here in Linglestown for the month!
Member Since: December 14, 2007 Posts: 278 Comments: 15045
110. NEwxguy
3:07 PM GMT on December 30, 2011
our non winter continues this weekend.Even the artic shot next week,isn't anything record breaking and will only last a couple of days.We only had a trace of snow in December so I went looking at past winters with light snowfall in December and most of them continued the this pattern,with some snowfall,but nothing major,a couple years rebounded to have normal snowfall totals,but a lot of others were below normal snowfall for the winter.
Member Since: September 6, 2007 Posts: 862 Comments: 15056
109. PhillySnow
12:36 PM GMT on December 30, 2011
We had flurries yesterday afternoon around 2pm. Nothing stuck, but it was a very welcome surprise!

35F here and supposed to go up to 51 today. *sigh*
Member Since: December 18, 2009 Posts: 0 Comments: 1210
108. listenerVT
3:50 AM GMT on December 30, 2011
Glad to see you all got the snow I sent down!!

;-)



Quoting Blizzard92:

hmmm, I didn't think it was ever clickable? That upslope effect really plows you guys with snow up there year after year. Even in the worst of winters (this one, lol), upslope never lets you down.



Whenever you hear: "Western slopes of the Green Mountains" ~ that's here!

Strange, I'm sure I've clicked on that map and come up elsewhere before. It might have been at Sully's, and I know Crowe made it clickable on his blog. Somehow I thought I'd done it from here too... *scratches head*


Member Since: July 11, 2007 Posts: 0 Comments: 5401
107. Zachary Labe
10:18 PM GMT on December 29, 2011
Getting a nice burst of probably 1mi light snow. Even parts of road getting a quick coating.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
106. TheF1Man
9:06 PM GMT on December 29, 2011
Quoting originalLT:
Blizz, like the term "heavy coating"! Would like the term "heavy snow accumulation" , better!


I'll take a coating at this point! I'm already tired of looking at bare limbs.
Member Since: February 23, 2010 Posts: 0 Comments: 669
105. originalLT
9:05 PM GMT on December 29, 2011
Blizz, like the term "heavy coating"! Would like the term "heavy snow accumulation" , better!
Member Since: January 31, 2009 Posts: 0 Comments: 7058
104. Zachary Labe
8:04 PM GMT on December 29, 2011
Light snow ending here in Linglestown, heavy coating here on most objects.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
103. Mason803
8:00 PM GMT on December 29, 2011
0.2" of snow here in Cashtown today. Brings my ytd snowfall to 4.6" which really isn't that bad all things considered.
Member Since: November 5, 2008 Posts: 0 Comments: 1139
102. Beachllama
6:05 PM GMT on December 29, 2011
Light snow in Germantown, MD, this is a pleasant surprise! Temp 37F.
Member Since: January 9, 2011 Posts: 0 Comments: 138
101. wunderstorm87
6:04 PM GMT on December 29, 2011
We have some surprise light snow coming down now. 31.7F
Member Since: August 5, 2010 Posts: 0 Comments: 588
100. Pcroton
4:58 PM GMT on December 29, 2011
Quoting originalLT:
Pcroton, good to hear from you again, was getting alittle worried! About the same weather for me here in Stamford. Thanks Tropic. for clarifying those posts.


Hey LT, goofy, and everyone else. Just been so very busy working that something had to take a back seat...and the internet was the one.

Member Since: September 26, 2011 Posts: 29 Comments: 5111
99. Pcroton
4:40 PM GMT on December 29, 2011
Quoting MariettaMoon:
12/22 RECORD HIGH MAXIMUM
Islip NY: 59F*

12/22 RECORD HIGH MINIMUMS
Norfolk VA: 55F (t)
Danville VA: 58F*


It got so warm when that system cranked up. I hit 62 here in Croton. Saw 18 last night. Sitting at 29 right now.

Looking cold next week though.

For northern Westchester county:

MONDAY NIGHT
MOSTLY CLOUDY. LOWS IN THE LOWER 20S.

TUESDAY
PARTLY SUNNY AND BRISK. COLD WITH HIGHS IN THE UPPER 20S.

TUESDAY NIGHT
PARTLY CLOUDY. COLD WITH LOWS AROUND 10 ABOVE. WIND
CHILL VALUES AS LOW AS ZERO.

WEDNESDAY
SUNNY. COLD WITH HIGHS IN THE MID 20S. WIND CHILL
VALUES AS LOW AS 5 BELOW IN THE MORNING.

Member Since: September 26, 2011 Posts: 29 Comments: 5111
98. Pcroton
4:38 PM GMT on December 29, 2011
Seeing some precip showing in central PA. Could this be a weak disturbance to give us a few snow showers this evening up here in SE NY and into CT/NJ? Where I am situated now even the smallest snow shower event means I usually get a dusting up here on this hill.
Member Since: September 26, 2011 Posts: 29 Comments: 5111
97. Zachary Labe
3:09 PM GMT on December 29, 2011
Nice lake effect snow outbreak next week and it is likely to be quite widespread. I would not be surprised if some of us east of the mountains get some light accumulations from a few rogue streamers. Snow belts should really get some higher totals.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
96. PhillySnow
2:22 PM GMT on December 29, 2011
Congratulations on your snow, Listener! Vermont is definitely on our list of places to retire when the time comes.

29F here this morning, and it's very welcome. Almost feels like winter.

MM - Thanks for the annual snowfall probabilities. Always good to have perspective.
Member Since: December 18, 2009 Posts: 0 Comments: 1210
95. Zachary Labe
2:00 PM GMT on December 29, 2011
Quoting listenerVT:


Not quite all. I'm about an hour below the Canadian border and temps have dropped into the teens already today and are aiming at sub-zero tonight.

But I made it safely home! =Whew!= It's treacherous out there. Came out of work to 3-4" of snow on my car, and underneath a hefty layer of ice. The wind is whipping, too. Not exactly conducive to the sneakers I was wearing. It's still snowing (about 1/2" per hour), here in the hometown of Snowflake Bentley.

You are all welcome to move here!


P.S.: Blizz, when you have chance, can you make the "Regional Advisories" graphic clickable again? Thanks!

hmmm, I didn't think it was ever clickable? That upslope effect really plows you guys with snow up there year after year. Even in the worst of winters (this one, lol), upslope never lets you down.
Member Since: December 14, 2007 Posts: 278 Comments: 15045
94. MariettaMoon
6:21 AM GMT on December 29, 2011
12/22 RECORD HIGH MAXIMUM
Islip NY: 59F*

12/22 RECORD HIGH MINIMUMS
Norfolk VA: 55F (t)
Danville VA: 58F*
Member Since: June 11, 2011 Posts: 36 Comments: 677
93. MariettaMoon
5:33 AM GMT on December 29, 2011
Just an addition to the average seasonal snowfall talk from before... I guess it's up to the personal preference on how to decifer what was a snowy season, an average season, or a season with little snowfall at a particular station.

On a 100 year seasonal snowfall record, a single season with a rediculously high amount of snowfall should only "skew" the average upwards only slightly. There will be more of an upward skew if that season occured during a 30 year seasonal snowfall record.

Some folks may prefer a median approach to measure the severity of a particular snow season at a location.

Most people will know this, but an "average" or "mean" is conducted by added the total snowfall of every season, and dividing the answer by the total number of seasons.

Most people will know this, but a "median" is conducted by lining up each seasons total from highest to lowest and taking the number in the exact middle of that list. If there are 100 seasons, count down 50 from the top and 50 from the bottom and take the value between each of those 2. (If those two values are 23.4" and 23.0", then 23.2" would be your median season snowfall). Or, seperate the 100 seasons into thirds. The highest third, the middle third, and the lower third to create a "range" of relative severity of snowfall seasons. Or, you might prefer a bell curve.

Some examples of Philadelphia are below...

(of 126 seasons from 1884-1885 to 2010-2011)

EXACT AVERAGE / MEAN: 22.7"

EXACT MEDIAN: 20.7"

HEAVIEST MEDIAN 1/3: 25.4" - 78.7"
MODERATE MEDIAN 1/3: 16.8" - 25.0"
LIGHTEST MEDIAN 1/3: T" - 16.5"

BELL CURVE...
# of years it snowed between…
78.0” – 83.9” = 1
72.0” – 77.9” = 0
66.0” – 71.9” = 0
60.0” – 65.9” = 1
54.0” – 59.9” = 2
48.0” – 53.9” = 1
42.0” – 47.9” = 5
36.0” – 41.9” = 6
30.0” – 35.9” = 9
24.0” – 29.9” = 19
18.0” – 23.9” = 34
12.0” – 17.9” = 28
6.0” – 11.9” = 12
0” – 5.9” = 8

% Chance of receiving at least X" in any guven season...
78.0” = 1%
72.0” = 1%
66.0” = 1%
60.0” = 2%
54.0” = 3%
48.0” = 4%
42.0” = 8%
36.0” = 13%
30.0” = 20%
24.0” = 35%
18.0” = 61%
12.0” = 83%
6.0” = 93%
T” = 100%
Member Since: June 11, 2011 Posts: 36 Comments: 677
92. originalLT
5:22 AM GMT on December 29, 2011
Thanks, MM.
Member Since: January 31, 2009 Posts: 0 Comments: 7058

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About Blizzard92

Cornell University- Atmospheric Sciences Student; Central PA SKYWARN Storm Spotter; American Meteorological Society Member; PA CoCoRaHS Branch Member

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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

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