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Central PA & Fringes - December-January 2014-15


djr5001

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PAZ024-025-033>035-061000- /O.NEW.KCTP.WW.Y.0002.150106T0800Z-150106T1800Z/ CAMBRIA-BLAIR-SOMERSET-BEDFORD-FULTON- INCLUDING THE CITIES OF...JOHNSTOWN...ALTOONA...SOMERSET... BEDFORD...MCCONNELLSBURG 232 PM EST MON JAN 5 2015

 

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM TO 1 PM EST TUESDAY... THE NATIONAL WEATHER SERVICE IN STATE COLLEGE HAS ISSUED A WINTER WEATHER ADVISORY FOR SNOW...WHICH IS IN EFFECT FROM 3 AM TO 1 PM EST TUESDAY. * LOCATIONS...LAUREL HIGHLANDS AND PORTIONS OF THE SOUTHERN MOUNTAINS. * HAZARD TYPES...SNOW. * SNOW ACCUMULATIONS...2 TO 4 INCHES. * TIMING...SNOW WILL BEGIN AROUND 3 AM TONIGHT WITH ACCUMULATING SNOWS ENDING LATE TUESDAY MORNING.

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Does anyone know why CTP has not yet updated their winter weather page (snowfall map) to reflect the incoming clipper? Not that I expect advisories up my way, nor any real significant snowfall, but I think that less than 24 from onset, they should at least have updated the accumulation map.

This, no wind advisories or headlines about upcoming wind chills ... seems like something's amiss.

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Does anyone know why CTP has not yet updated their winter weather page (snowfall map) to reflect the incoming clipper? Not that I expect advisories up my way, nor any real significant snowfall, but I think that less than 24 from onset, they should at least have updated the accumulation map.

it may have been updated since you posted this because I just hit refresh and it is there now

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Seems like the wind was pretty intense back in PA last night. Snow looks good for the Commonwealth with the Laurels looking like a good bet for 4"+ and 1-4" elsewhere. I'll just enjoy it from the stands as I'm still out in Phoenix for the remainder of the week. I'll just take my 70's and like it I guess :D

You just might be the smart one with the cold temps this week.

Looking for IPT to get an 1-2" with this clipper. Anyone know when it is suppose to start.

Edit:

000

WWUS41 KCTP 051932

WSWCTP

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE STATE COLLEGE PA

232 PM EST MON JAN 5 2015

.A QUICK MOVING ALBERTA CLIPPER WILL BRING SEVERAL INCHES OF SNOW

TO THE REGION LATE TONIGHT INTO TUESDAY.

PAZ024-025-033>035-061000-

/O.NEW.KCTP.WW.Y.0002.150106T0800Z-150106T1800Z/

CAMBRIA-BLAIR-SOMERSET-BEDFORD-FULTON-

INCLUDING THE CITIES OF...JOHNSTOWN...ALTOONA...SOMERSET...

BEDFORD...MCCONNELLSBURG

232 PM EST MON JAN 5 2015

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM TO 1 PM

http://forecast.weather.gov/product.php?site=NWS&issuedby=CTP&product=WSW

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You just might be the smart one with the cold temps this week.

Looking for IPT to get an 1-2" with this clipper. Anyone know when it is suppose to start.

Edit:

000

WWUS41 KCTP 051932

WSWCTP

URGENT - WINTER WEATHER MESSAGE

NATIONAL WEATHER SERVICE STATE COLLEGE PA

232 PM EST MON JAN 5 2015

.A QUICK MOVING ALBERTA CLIPPER WILL BRING SEVERAL INCHES OF SNOW

TO THE REGION LATE TONIGHT INTO TUESDAY.

PAZ024-025-033>035-061000-

/O.NEW.KCTP.WW.Y.0002.150106T0800Z-150106T1800Z/

CAMBRIA-BLAIR-SOMERSET-BEDFORD-FULTON-

INCLUDING THE CITIES OF...JOHNSTOWN...ALTOONA...SOMERSET...

BEDFORD...MCCONNELLSBURG

232 PM EST MON JAN 5 2015

...WINTER WEATHER ADVISORY IN EFFECT FROM 3 AM TO 1 PM

http://forecast.weather.gov/product.php?site=NWS&issuedby=CTP&product=WSW

 

Advisory start time looks pretty good when comparing to the early looks from the HRRR and RAP, which have precip entering the central counties around 2-3 am. Precip gets to IPT around 5am-ish.

 

Model runs yesterday shifted this weak system a bit to the south of where it had been, focusing the axis of heavier snows more on the southern tier. In fact, it's looking like the stuff that might've been capable of delivering a stripe of scattered 4-6 inch amounts thru the middle of the state is going to go into the western MD/West VA ridges to die. The air mass had trended colder on the models and thus pressed this south a bit. I think advisory placement is OK although it's weird their map continues the 2-4 in the Sus Valley if they decided not to put advisories. 1-2 might end up being the better bet in that area anyways since it currently appears the precip with the best rates might skirt or stay south and downsloping may come into play a bit. Otherwise, the rest of the area save for possibly the extreme northern tier should see a T-2 event. While this should be a high ratio event (at least a 14-15:1), I think we may be missing the good lift (very weak system) and slightly too cold aloft in the snow growth zone to get the optimum setup for the 20:1+ stuff. Exceptions to this would be the Laurels region, as the extra lift generated from the orographic forcing could offer up better rates and ratios. Some very high parts of Somerset and southern Cambria County might sneak a 5-6" amount.

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Advisory start time looks pretty good when comparing to the early looks from the HRRR and RAP, which have precip entering the central counties around 2-3 am. Precip gets to IPT around 5am-ish.

 

Model runs yesterday shifted this weak system a bit to the south of where it had been, focusing the axis of heavier snows more on the southern tier. In fact, it's looking like the stuff that might've been capable of delivering a stripe of scattered 4-6 inch amounts thru the middle of the state is going to go into the western MD/West VA ridges to die. The air mass had trended colder on the models and thus pressed this south a bit. I think advisory placement is OK although it's weird their map continues the 2-4 in the Sus Valley if they decided not to put advisories. 1-2 might end up being the better bet in that area anyways since it currently appears the precip with the best rates might skirt or stay south and downsloping may come into play a bit. Otherwise, the rest of the area save for possibly the extreme northern tier should see a T-2 event. While this should be a high ratio event (at least a 14-15:1), I think we may be missing the good lift (very weak system) and slightly too cold aloft in the snow growth zone to get the optimum setup for the 20:1+ stuff. Exceptions to this would be the Laurels region, as the extra lift generated from the orographic forcing could offer up better rates and ratios. Some very high parts of Somerset and southern Cambria County might sneak a 5-6" amount.

 

Thanks for your continued input on this system MAG. At this point I'd be thrilled to see 2" here, but expecting around 1. Hoping at least a few in this forum can eek out a 3-4" event  :snowing:

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Things still look on track for 2 to 3 inches in these parts. Does CTP wait until after the snow falls to issue advisories. Very odd. This will likely mess up school in the am here. Bad timing.

 

CTP did issue advisories for their southwestern counties of Cambria, Somerset,Blair, Bedford, and Fulton for 2-4 inches. I'm not sure why they wouldn't for the Sus Valley if their map suggests the same types of amounts. Philly has advisories all the way to Allentown despite them showing a CWA wide 1-2 inches in their realm (probably issuing for impact purposes with rush hour timing over amounts). LWX has lower thresholds in their CWA.

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Hate to speak poorly of them, but there is and always has been a bias towards warm with these guys...and they are often last to pull the trigger on adv/warn in CPA.  As we also get to read Mt. Holly and Pitt's discussions, you will see a more balances/proactive discussion of models and related watch/warnings that may be posted.  I get that some of us like it cold and some warm, but in the business of the weather....it is what it is, and I feel they sometimes do more of a disservice in being "late to the dance".  I'd much rather see something issued then tempered back, than to have a last minute notification for the "normal" folks that do not follow the passion of most on this board.

 

JMO's 

 

Nut

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CTP not having an advisory for the Lower Susq. Valley makes 0.0 sense.

Mt. Holly forecast discussion just was updated with their reasoning for expanding their advisory further north and west due to timing and impact on the am commute. Not advising due to criteria is a disservice to the public and does not help to protect life or property as their mission suggests. Hopefully CTP overnight fee will see that the spirit of the criteria is what matters most.

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I asked CTP on facebook why no advisories, they just posted this answer:

"The reason is our advisory criterion is 3" average over half or more of a county. We have to use the mid point of ranges, so we would need to forecast 2-4 inches to justify an advisory, Overall we are just expecting a light snow which for mid winter is pretty commonplace."

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I asked CTP on facebook why no advisories, they just posted this answer:

"The reason is our advisory criterion is 3" average over half or more of a county. We have to use the mid point of ranges, so we would need to forecast 2-4 inches to justify an advisory, Overall we are just expecting a light snow which for mid winter is pretty commonplace."

For midwinter it may be commonplace....but for this winter....its quite a rare occurrence, and at least until we get a few "under our belt" a proactive/safe approach would be a smart play.

 

Like I said, they are always last, and if they decided to do it overnight, it's too late IMO.  I'm not using my sno goggles to read into this, but they are about public information.  To me, I dont care..I know its gonna snow, and many ask me when and how much...but to the average Joe, public awareness is important, as they do not spend the time on weather boards like us.  

 

Wasting gazzilions of dollars on special announcement boards while driving along interstates is too late for most.  At that point to me its like....No $hit sherlock.

 

Nut

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Well with the latest Gfs they will likely have to pull the trigger for York and Adams overnight. I see the nightmare that 1-2 inches of snow causes on 83 around here. With modern road congestion etc they should consider lowering the criteria or adding a snow advisory to the list advising the general public of snow covered roads.

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Well with the latest Gfs they will likely have to pull the trigger for York and Adams overnight. I see the nightmare that 1-2 inches of snow causes on 83 around here. With modern road congestion etc they should consider lowering the criteria or adding a snow advisory to the list advising the general public of snow covered roads.

To be fair a sunny 72 degree day causes havoc on 83 ...

Sticking with my .75" MDT prediction.

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As promised, here is my map via a different method than I usually do. Normally I just draw my snow zones over a map using powerpoint. This way uses ArcGIS software and making a layout for the results. For any folks that are familiar, it interpolates the map off of the different stations I put on the map and had labelled. Snow amounts were calculated from taking the ratio x QPF. Highest ratios I used were 20:1 in the Laurels Region. Pittsburgh area, SW PA, and southern tier were 17:1. I-80 corridor and Sus Valley were 14-15:1. Far northern tier 12:1. Best precip and lift will run along southern PA. It gets a bit too cold aloft and your away from the best lift for optimum snow rates the further north you go, hence the reason for tapered ratios. 

 

I entered about 170 points to make the map produced from the interpolation nice and smooth and entered QPF as best as I could via comparing total precip off the various models, which are pretty close at this point. This is a really low QPF event (I entered a lot of 0.15 and 0.2 amounts) so ratios will factor more into if these amounts verify than it usually does. It's a work in progress, it took me awhile enter the points. But I can use this and improve on it for future events.

 

post-1507-0-89214000-1420529413_thumb.pn

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As promised, here is my map via a different method than I usually do. Normally I just draw my snow zones over a map using powerpoint. This way uses ArcGIS software and making a layout for the results. For any folks that are familiar, it interpolates the map off of the different stations I put on the map and had labelled. Snow amounts were calculated from taking the ratio x QPF. Highest ratios I used were 20:1 in the Laurels Region, Pittsburgh area, SW PA, and southern tier were 17:1. I-80 corridor and Sus Valley were 14-15:1. Far northern tier 12:1. Best precip and lift will run along southern PA. It gets a bit too cold aloft and your away from the best lift the further north for optimum snow rates the further north you go, hence the reason for tapered ratios. 

 

I entered about 170 points to make the map produced from the interpolation nice and smooth and entered QPF as best as I could via comparing total precip off the various models, which are pretty close at this point. This is a really low QPF event (I entered a lot of 0.15 and 0.2 amounts) so ratios will factor more into if these amounts verify than it usually does. It's a work in progress, it took me awhile enter the points. But I can use this and improve on it for future events.

 

attachicon.gifJan 6 Snowmap.png

Nice looking map...Will gladly take my 2-3" and be happy ;)

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