Central PA thread - Spring-like weather now, but...

[EasternUSWX]

GFS says nothing to see here folks!! Move along.

Where have you been. It has said that all along. However, this run is very close to phasing. 0Z should do it.

[NortheastPAWx]

CTP:

THE DRAMATIC AMPLIFICATION OF THE UPPER LEVEL PATTERN COMBINED

WITH AVAILABLE TROPICAL MOISTURE (A HARDLY EVER SEEN 3.01"

BULLSEYE OF PRECIPITABLE WATER PROGGED WELL OFF THE CAROLINA COAST

SUNDAY AFTERNOON FOR INSTANCE) MEANS THE STAGE IS SET FOR A LARGE

ATMOSPHERIC RESPONSE LATE THIS WEEKEND AND EARLY NEXT WEEK...BUT THE

MILLION DOLLAR QUESTION IS WHAT EXTENT WILL IT IMPACT COASTAL

AREAS AND ULTIMATELY HAVE OVER PA? WE CANNOT ANSWER THAT QUESTION

WITH MUCH CONFIDENCE TODAY...BUT MODEL CONSENSUS AND CONSISTENCY

CONTINUES TO GIVE CONFIDENCE AND CREDENCE TO PREVIOUS SOLUTIONS OF

A TROPICAL STORM OR HURRICANE (SANDY) UNDERGOING POTENTIAL

EXTRATROPICAL TRANSITION AND CONTINUED EXPLOSIVE DEEPENING EARLY

NEXT WEEK...WITH POTENTIAL SIGNIFICANT IMPACTS TO COASTAL AREAS

AND EVEN THE POTENTIAL FOR HIGHER ELEVATION SNOWFALL. PROXIMITY TO

THE COAST REMAINS THE BIG QUESTION.

WHILE CURRENT FORECASTS DO NOT REFLECT THE LOWER PROBABILITY HIGH

IMPACT OUTLIER SOLUTION AT THIS TIME...WE`VE REMAINED CONSISTENT

WITH MID RANGE CHC POPS AND TIMING TIED TO THE NORTHWARD

PROGRESSION OF THE TROPICAL AND THEN EXTRATROPICAL CYCLONE... AND

INTERACTION WITH THE APPROACHING LONGWAVE TROF FROM THE GREAT

LAKES AND OHIO VALLEY ON SATURDAY. ECMWF SOLUTION REMAINS THE MOST

ENTICING AND DRAMATIC...AND WOULD RESULT IN A STORM OF EPIC

PROPORTION TO SAY THE LEAST FOR COASTAL AREAS SPANNING FROM THE

MID ATLANTIC NORTHWARD TO SOUTHERN NEW ENGLAND. DIALING IT

BACK THOUGH...SUCH A SOLUTION HAS A 20 PERCENT OR LESS CHANCE OF

OCCURRING AS WE ARE 5+ DAYS OUT. STAY TUNED AS WE`LL OBVIOUSLY BE

WATCHING CLOSELY AND TWEAKING FORECASTS AS THE WEEK WEARS ON.

[MAG5035]

Where have you been. It has said that all along. However, this run is very close to phasing. 0Z should do it.

Actually not necessarily, it was one of the first on the scene when computer models started going off the deep end Sat night/Sun, the GFS 12z Sunday had a sub 960 off the Delmarva that curled in. Just check out the very first page of the New England Sandy thread... specifically posts 1-6.

[Santa Clause]

Good points MAG!! Basically the Euro is the worst case scenario...very very unlikely that comes close to panning out. More likely is a blend of the two...New England only needs slight shifts to be in trouble though. If Euro would come true, some areas would see destructive flooding to say the least!!

[Eskimo Joe]

Wow

Matt Noyes ‏@MattNoyesNECN

12Z GFS Ensemble Mean: http://ow.ly/i/13khk 12Z EC Ensemble Mean:http://ow.ly/i/13khv Now that's a match.

[JamieOber]

Good points MAG!! Basically the Euro is the worst case scenario...very very unlikely that comes close to panning out. More likely is a blend of the two...New England only needs slight shifts to be in trouble though. If Euro would come true, some areas would see destructive flooding to say the least!!

Really for here, the worst case scenario is not flooding but snow. There are still a fair amount of leaves on the trees and if we even get several inches of snow with high winds, that's a big problem.

[NeffsvilleWx]

Sorry to interrupt the doomsday storm conversation, but this ran in the local paper today regarding last friday's tornado.

http://lancasteronli...ter-County.html

Apparantly, a tornado warning for solanco WAS issued, 8 minutes after the tornado did it's deed. They (NWS state college) said that (paraphrased) the criteria wasn't met to issue a warning. However, radar returns showed that there was a very high likelyhood that there was a tornado on the ground (I realize that there is some lag time between radar sweeps, and hindsight is 20/20). TOR's were issued for harford county in northern maryland, and i believe part of berks/lebanon counties, but not lancaster. I would think the reports of a tornado on the ground in harford county should have instantly put CTP on alert to notify solanco. As a result, 15 people were injured, but it could have easily been much worse.

Did CTP take the "best" course of action? Or should they have issued it sooner?

[JamieOber]

Sorry to interrupt the doomsday storm conversation, but this ran in the local paper today regarding last friday's tornado.

http://lancasteronli...ter-County.html

Apparantly, a tornado warning for solanco WAS issued, 8 minutes after the tornado did it's deed. They (NWS state college) said that (paraphrased) the criteria wasn't met to issue a warning. However, radar returns showed that there was a very high likelyhood that there was a tornado on the ground (I realize that there is some lag time between radar sweeps, and hindsight is 20/20). TOR's were issued for harford county in northern maryland, and i believe part of berks/lebanon counties, but not lancaster. I would think the reports of a tornado on the ground in harford county should have instantly put CTP on alert to notify solanco. As a result, 15 people were injured, but it could have easily been much worse.

Did CTP take the "best" course of action? Or should they have issued it sooner?

The storm weakened before it got there then reintensified. Given this was not an ordinary tornado situation, this is a difficult call to make. There was also no ground reports received due to night.

The flip side of this is people in Bucks County no doubt thought "what tornado, wrong again" since there were few damage reports.

Having dealt with the public while working at AccuWeather, I've learned how much of a fine line this all is.

[NeffsvilleWx]

The storm weakened before it got there then reintensified. Given this was not an ordinary tornado situation, this is a difficult call to make. There was also no ground reports received due to night.

The flip side of this is people in Bucks County no doubt thought "what tornado, wrong again" since there were few damage reports.

Having dealt with the public while working at AccuWeather, I've learned how much of a fine line this all is.

I do realize that it's a very difficult situation. On one hand, if you warn everything, the public becomes complacent and bodily harm. On the other, you only warn confirmed events, and risk bodily harm.

It's really a catch 22. I would think that, at least, a severe t-storm warning would have been appropriate, given the previous probability of tornadic activity.

I was getting ready for bed when this all went down, had no idea and I'm less than 20 miles away. I know this is subjective, but was there really enough attenuation before crossing into PA to only issue a special wx statement?

[JamieOber]

I do realize that it's a very difficult situation. On one hand, if you warn everything, the public becomes complacent and bodily harm. On the other, you only warn confirmed events, and risk bodily harm.

It's really a catch 22. I would think that, at least, a severe t-storm warning would have been appropriate, given the previous probability of tornadic activity.

I was getting ready for bed when this all went down, had no idea and I'm less than 20 miles away. I know this is subjective, but was there really enough attenuation before crossing into PA to only issue a special wx statement?

A couple of things. I remember this: http://www.americanwx.com/bb/index.php/topic/36936-october-2012-obs-and-discussion/page__st__385#entry1798233 and wondering if there was a tornado at all.

This is a key part of the story,,,the question is, should they have warned on a storm that was intensifying but not as yet a severe storm...judgement call:

Following a "credible report" of a funnel cloud sighting in Baltimore County, the NWS at 6:52 p.m. issued a second tornado warning, this one for Harford County, Md., just south of York, through 7:30 p.m.

Meanwhile, NWS meteorologists in State College, which monitors Lancaster County weather, were tracking the same storms, which appeared to wane as they headed here, Jung said.

"The storms' circulation over Lancaster County was not as strong as what we had to the south," he said. "The overall structure looked like it was weakening."

In addition, at that point the NWS had yet to confirm the tornado sighting in Maryland, Jung said.

As one of the storms neared the county, it intensified, prompting the NWS at 7:58 p.m. to issue a special weather statement indicating a strong thunderstorm near Holtwood, moving northeast at 30 mph, with heavy rains and wind gusts to 40 mph.

As the storm continued to intensify, the NWS upgraded that statement at 8:18 p.m. to a severe thunderstorm warning indicating a storm packing winds in excess of 60 mph.

Read more: http://lancasteronline.com/article/local/762529_Weather-service-explains-lack-of-warning-for-Friday-s-tornado-in-Lancaster-County.html#ixzz2AAjc88ml

[JamieOber]

GFS says nothing to see here folks!! Move along.

From poking around the other subforums, it appears that the 18z is further west and the ensembles are farther west than the operational.

[Eskimo Joe]

From poking around the other subforums, it appears that the 18z is further west and the ensembles are farther west than the operational.

Correct. Consensus building on a NJ -> eastern Long Island "landfall". I'm still waiting until Thursday evening before getting 'excited' over this.

[tombo82685]

Just from going off the euro, i think the laurels into garret county md would be the place to be if good precip can get back there. The northern tier where the euro has 18+ looks suspect to me. The thicknesses are above 546, a sneaky warm layer looks to be in the sounding somewhere also.

[Eskimo Joe]

From Hurricane Hunters:

00

URNT12 KNHC 240035

VORTEX DATA MESSAGE AL182012

A. 24/00:09:40Z

B. 14 deg 44 min N

077 deg 10 min W

C. 850 mb 1339 m

D. 39 kt

E. 305 deg 29 nm

F. 065 deg 40 kt

G. 312 deg 41 nm

H. 991 mb

I. 16 C / 1519 m

J. 20 C / 1519 m

K. NA / NA

L. Ragged Eye

M. C32

N. 12345 / 8

O. 0.02 / 4 nm

P. AF302 0318A SANDY OB 10

MAX OUTBOUND AND MAX FL WIND 57 KT SE QUAD 00:25:00Z

Additoinal spiral band 20nm dia in eye

;

[MAG5035]

Sorry to interrupt the doomsday storm conversation, but this ran in the local paper today regarding last friday's tornado.

http://lancasteronli...ter-County.html

Apparantly, a tornado warning for solanco WAS issued, 8 minutes after the tornado did it's deed. They (NWS state college) said that (paraphrased) the criteria wasn't met to issue a warning. However, radar returns showed that there was a very high likelyhood that there was a tornado on the ground (I realize that there is some lag time between radar sweeps, and hindsight is 20/20). TOR's were issued for harford county in northern maryland, and i believe part of berks/lebanon counties, but not lancaster. I would think the reports of a tornado on the ground in harford county should have instantly put CTP on alert to notify solanco. As a result, 15 people were injured, but it could have easily been much worse.

Did CTP take the "best" course of action? Or should they have issued it sooner?

Also something that might not be known too greatly, Lancaster county is in a tough spot really when you want to track severe weather via NEXRAD. There's three radars nearby that can technically cover Lancaster County: CCX (State College), DIX (Philly's radar that is located in central NJ), and LWX (Sterling, VA). Of the three radars, DIX is the "closest" radar and its beam at the lowest angle is at around 8k feet in the tornado warned area. The other two hit at about 10-11k feet. Thus, you cannot see velocities or anything below that level, making it difficult to judge if the rotation you might see at 8k feet is getting to the surface. From the radar imagery I saw (though admittedly i'd probably need a harder look to give a better judgement) there was some rotation evident at the time but the strength of it didn't look like a slam dunk to issue/continue the tornado warning. You probably saw my post back on page 12 #418 about the correlation coefficient product possibly picking up a tornadic debris signature. But with the height of the beam, which was getting near the freezing layer at that height.. that can debatable too. It's a tough call. They did note some rotation detected in the severe thunder storm warning right?

[MAG5035]

Really for here, the worst case scenario is not flooding but snow. There are still a fair amount of leaves on the trees and if we even get several inches of snow with high winds, that's a big problem.

At this point, all the leaves that are left are mostly the ones on the oak trees here. I'd say we're probably about where we were for the October 29th storm last year. There really wasn't too many issues with that storm since the heaviest snow fell in the high ground which lost most of all its leaves by that point and the few inches we saw in the valley. Contrast that to the debacle we had in Oct 09' since it came two weeks earlier and most trees still had foliage. I'm only speaking to the prospect of seeing a "normal" once in a generation October snowfall... if we get 20-40" with the wind like some of the euro runs have been depicting there's no getting around the monumental impact to the area that would cause.

[Santa Clause]

Sorry guys, I'm just in way over my head. How is a tropical system going to bring snow to anyone??? Also wouldn't flooding be a threat for most in CPA with slow moving storm system?? Also wouldn't it need a more western threat for the bigger threat of tropical storm winds/heaviest rainfall??

[WxLover]

Also something that might not be known too greatly, Lancaster county is in a tough spot really when you want to track severe weather via NEXRAD. There's three radars nearby that can technically cover Lancaster County: CCX (State College), DIX (Philly's radar that is located in central NJ), and LWX (Sterling, VA). Of the three radars, DIX is the "closest" radar and its beam at the lowest angle is at around 8k feet in the tornado warned area. The other two hit at about 10-11k feet. Thus, you cannot see velocities or anything below that level, making it difficult to judge if the rotation you might see at 8k feet is getting to the surface. From the radar imagery I saw (though admittedly i'd probably need a harder look to give a better judgement) there was some rotation evident at the time but the strength of it didn't look like a slam dunk to issue/continue the tornado warning. You probably saw my post back on page 12 #418 about the correlation coefficient product possibly picking up a tornadic debris signature. But with the height of the beam, which was getting near the freezing layer at that height.. that can debatable too. It's a tough call. They did note some rotation detected in the severe thunder storm warning right?

That is correct MAG, the SVTW did mention some rotation was detected. If Phil. NEXRAD has a closer beam , would they would be able to detect a tornado sig. more accurately than CCX.

[Sunny and Warm]

Sorry guys, I'm just in way over my head. How is a tropical system going to bring snow to anyone??? Also wouldn't flooding be a threat for most in CPA with slow moving storm system?? Also wouldn't it need a more western threat for the bigger threat of tropical storm winds/heaviest rainfall??

While Sandy may still have some warm core features, she will be post-tropical by that time, and will perform similarly to a noreaster such as occurred last October, only on a much grander scale if her energy gets captured by the mid latitude trough. The depiction of her being at 940-ish mb's does not mean it will be a cat 4 hurricane. It means that the trough is lending energy to what WAS Sandy, and she achieves that pressure through non-tropical processes such as you would see along the coast in winter with a developing noreaster.

[Jmister]

Sorry guys, I'm just in way over my head. How is a tropical system going to bring snow to anyone??? Also wouldn't flooding be a threat for most in CPA with slow moving storm system?? Also wouldn't it need a more western threat for the bigger threat of tropical storm winds/heaviest rainfall??

You would be right, a purely tropical system would make it nearly impossible to produce snow or have a large precip field. However, Sandy will not be purely tropical by the time it nears the coast (assuming it does so). Take a look at the Euro. First plot is the 150 hr forecast that shows Sandy remaining warm-core and thus still mostly tropical. By 162, it is beginning to transition to an extratropical system (baroclinic - requiring a temperature gradient). Once extratropical, the storm will expand with respect to wind field, pressure field, and precip field. Additionally, it will NOT bring in tropical warmth as it makes "landfall."

edit: the extratropical transition is better illustrated by 168, but I'm too lazy to get a new screen grab.

[JamieOber]

Sorry guys, I'm just in way over my head. How is a tropical system going to bring snow to anyone??? Also wouldn't flooding be a threat for most in CPA with slow moving storm system?? Also wouldn't it need a more western threat for the bigger threat of tropical storm winds/heaviest rainfall??

We got snow from Wilma in 2005.

[MAG5035]

Just from going off the euro, i think the laurels into garret county md would be the place to be if good precip can get back there. The northern tier where the euro has 18+ looks suspect to me. The thicknesses are above 546, a sneaky warm layer looks to be in the sounding somewhere also.

Yea thats an interesting aspect, 1000-500mb thicknesses are a good bit more than you would usually think would be the case. I had to dig out the other key thickness numbers to decipher where the 1000-500 thickness was getting stretched out. I used hour 174 just for a sample since thats one of the better frames for the storm itself retrograding into PA and It's def good from 850 on down. 850's are sufficient and although 925s are marginal at just barely above 0.. anyone with elevation is likely seeing snow. Overall, 1000-850 thickness was easily below the magic number of 1320 in most of PA at this hour on the Euro. It appears to me that the "warm" layer is occurring up higher at like 700mb. And indeed, temps at 700mb are actually the same or a bit warmer at 700mb, than at 850mb in Northern PA. But still near and below zero at that level. And lastly, I had a look at 850-500 thickness and it was higher than that magic number (4100) everywhere in PA, compared to roughly ranging from 4140 to 4200 west to east across the central third. So IMO, it seems abnormally warm for a snow event between 850 and 500mb but still cold enough to allow snow all the way down to the level the boundary layer temps would allow. I'm sure this probably has something to do with the tropical origins of this system. At any rate, certainly wouldn't imagine high totals like the Euros putting out if it assumes 10:1, as the warm mid levels probably would compromise snow growth among the usual issues you'd have with October snow. Precip rates were def not the insanity in PA that they were in this mornings Euro either.

Well that ended up being a big post on that subject, haha.

[Eskimo Joe]

Also something that might not be known too greatly, Lancaster county is in a tough spot really when you want to track severe weather via NEXRAD. There's three radars nearby that can technically cover Lancaster County: CCX (State College), DIX (Philly's radar that is located in central NJ), and LWX (Sterling, VA). Of the three radars, DIX is the "closest" radar and its beam at the lowest angle is at around 8k feet in the tornado warned area. The other two hit at about 10-11k feet. Thus, you cannot see velocities or anything below that level, making it difficult to judge if the rotation you might see at 8k feet is getting to the surface. From the radar imagery I saw (though admittedly i'd probably need a harder look to give a better judgement) there was some rotation evident at the time but the strength of it didn't look like a slam dunk to issue/continue the tornado warning. You probably saw my post back on page 12 #418 about the correlation coefficient product possibly picking up a tornadic debris signature. But with the height of the beam, which was getting near the freezing layer at that height.. that can debatable too. It's a tough call. They did note some rotation detected in the severe thunder storm warning right?

This times a million. I have found that WGAL radar gives a better radar presentation for Lancaster and York Counties, especially during the winter when you are watching virga.

[NortheastPAWx]

So yeah, about that storm y'all...GFS looking more west potentially

[MAG5035]

Killing some time before the 0z runs. This is one of about 6 deer in the yard right now.

[EasternUSWX]

GFS OP getting owned by its own ENS. lol

[EasternUSWX]

Euro takes central PA to the cleaners. Then blows up the cleaners.... lol

[MAG5035]

Euro takes central PA to the cleaners. Then blows up the cleaners.... lol

Yea KJST, KAOO, and KUNV are up over 3" total in the text on just the 6 hour frames that you could argue snow. Euros gonna be makin another 24-48 weenie map outta this one probably.

[EasternUSWX]

Yea KJST, KAOO, and KUNV are up over 3" total in the text on just the 6 hour frames that you could argue snow. Euros gonna be makin another 24-48 weenie map outta this one probably.

Wunderground maps show 12" at my house so ya. lol

[MAG5035]

I do notice this high thickness thing again with the run. with sufficient 850's and 2m temps maybe a degree or two above freezing, thickness runs in the high 540s at AOO and UNV. I'd imagine it's the warmer mid-levels around 700mb driving that figure up again like I was explaining earlier.