Central PA - February 2016

[r-ville]

WPC thoughts

 

EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1107 AM EST SUN JAN 31 2016

VALID 12Z WED FEB 03 2016 - 12Z SUN FEB 07 2016

...A STORMY START TO FEBRUARY FOR THE NATION...


...GUIDANCE/PREDICTABILITY ASSESSMENT...

THE 06 UTC GFS/GEFS AND 00 UTC ECMWF/ECMWF ENSEMBLES STILL OFFER
EMPHASIS DIFFERENCES BUT HAVE OVERALL COME INTO A BETTER CLUSTERED
SOLUTION WITH MAIN SYSTEMS DURING THE UPCOMING MEDIUM RANGE
FORECAST PERIOD. THIS BOLSTERS FORECAST CONFIDENCE TO SLIGHTLY
ABOVE NORMAL LEVELS...ALBEIT WITH MORE UNCERTAINTY WITH THE MORE
COMPLEX AND SENSIBLE WEATHER FOCUSING SMALL-MID SCALE INTERACTION
AND FOCUS. A FAVORED COMPOSITE BLEND OF THESE GUIDANCE PIECES
ACTED AS THE TEMPLATE FOR THE WPC MEDIUM RANGE FORECAST SUITE.


...SENSIBLE WEATHER HIGHLIGHTS/THREATS...

THE HEAVIEST SNOW AND STRONGEST WINDS ASSOCIATED WITH A MAIN LEAD
SYSTEM TRACKING AWAY FROM GREAT LAKES/NORTHEAST WILL BE WINDING
DOWN AFTER MIDWEEK...BUT COLD CYCLONIC FLOW BEHIND THE STORM AND
SEVERAL TRAILING WEAKER CLIPPER SYSTEMS MAY SUPPORT SOME PERIODS
OF ORGANIZED SNOW THROUGH THE REST OF THE WEEK. THE EXTENT OF
COOLING IS MORE UNCERTAIN GIVEN COMPLEX NRN STREAM FLOW FROM
CANADA. EXPECT WAVINESS ALONG THE FRONT TRAILING FROM THE GREAT
LAKES STORM TO MEANWHILE RESULT IN ENHANCED RAINFALL ALONG
PORTIONS OF THE EAST COAST WED/THU AND SOME THREAT FOR ICE/SNOW
INTO THE SERN US/MID-ATLANTIC WITH IMPULSE/WAVE DEVELOPMENT
THU/FRI. AN EAST COAST WINTER COASTAL STORM THREAT IS POSSIBLE
LATE NEXT WEEKEND WITH NRN AND SRN STREAM FLOW AMPLIFICATION
ALOFT...BUT IMPORTANT DETAILS STILL NEED TO BE RESOLVED. THESE
RESULT IN PART FROM APPROACHING ENERGY ASSOCIATED WITH TWO DYNAMIC
SHORTWAVE TROUGHS EXPECTED TO SLAM INTO THE NORTHWEST THEN SEWD
ACROSS THE WRN US THU/FRI AND AGAIN NEXT WEEKEND. THESE ACTIVE WRN
US SYSTEMS SHOULD GENERATE SWATHS OF ENHANCED PCPN MAINLY FROM THE
CENTRAL-NRN WEST WEST COAST THROUGH THE NORTH-CENTRAL
INTERMOUNTAIN WEST AND ROCKY STATES AS ENHANCED BY LOCAL TERRAIN
AND FAVORABLE UPPER SUPPORT.

SCHICHTEL

 

[pasnownut]

WPC thoughts

where you been all my life Rville.....

 

I love this guy....

 

 

thx for the encouraging find....

 

Nut

[canderson]

Not sure if anyone has noticed but the Midwest is getting a big storm and blizzard Tuesday and Wednesday.

The Euro has sucked for their storm as well.

[Eskimo Joe]

Something ain't right with the OP Euro these past two weeks.  PARA Euro, Euro ENS and OP GFS have been taking it to the cleaners.

[TugHillMatt]

Her ya go guys (and gals). I've been doing You Tube videos for awhile now giving folks a glimpse into my day as a truck driver showing where I go and what I encounter out on the road. Here is one from yesterday.

 

 

You definitely have the Northeast PA accent. My dad is from Hazleton, and we still have a lot of family there. My parents live in Danville now.

 

Snowing only in Hazleton? There's a surprise...not!

[r-ville]

UKIE is pretty close for the upcoming weekend.

Then as we move forward, the GFS tries to phase a northern stream piece (over the GL's) with a coastal reflection which, to the bleary eye, seems to form along the tail end of the stationary front in the W Atl.

 

 

The western ridge, as shown in H5 maps, is really decent, just a bit displaced west but not by much - also slightly positive crest to its structure, which is also not ideal but may work in this situation.

 

If only there were some help downstream (even if transient) the storm centering on 2/9-10 would be a bigger hit than the nuisance type event being modeled at present.

[r-ville]

 

[heavy_wx]

52 F this morning...snow cover obliterated.

[sauss06]

Glad to see you posting again R-ville.......... and happy to see you bringing some storms with you 

[AllWeather]

52 F this morning...snow cover obliterated.

We've had some crazy inversions down here in the S Susq Valley the last couple days. Currently 34 F in Lancaster while Coatesville sitting in the mid 40s. Snow cover holding on

[Voyager]

It was 31 at my house in Tamaqua and 47 in Hazleton this morning.

[r-ville]

 

12z GFS places emphasis on the system near the 8th and quashes the threat for the 10th time period. Solid hit for most of PA - but is it correct? The other models seem to want to favor the latter of the two.

 

With all the Pac energy running around, models will probably continue to exhibit differences in exact timing which leads to varying solutions on the Operational runs.

[djr5001]

Has anyone else noticed that KMDT has been much colder than surrounding sites today?  With a breeze out of the northwest I am wondering if this is being influenced by the mountains of snow on city island creating a cold pool of air that is being channeled down the river to the ASOS site.

 

[canderson]

Has anyone else noticed that KMDT has been much colder than surrounding sites today? With a breeze out of the northwest I am wondering if this is being influenced by the mountains of snow on city island creating a cold pool of air that is being channeled down the river to the ASOS site.

KMDT_temp_02012016.jpg

I can confirm it's FREEZING downtown with the wind coming off Snow Mountain.

I'd bet MDT has a good snow bunker around their station, too.

[MAG5035]

Been rather uncertain about the upcoming pattern after our cutter goes through early this week. The cold coming right behind the cutter doesn't look as biting and def more transient than had previously been progged. There certainly appears to be a pretty decent amplification in the cards right around that Feb 9-10th timeframe as has been consistently modeled the last several days with the PNA making a major spike. That much seems certain, but the details are certainly all over the place with the pieces running around that may or not put a big system together. There could also be temp issues with the cold lessening ahead of whatever system forms, especially towards the I-95 corridor. Phasing of course is a big thing, as little or none probably presents a lighter event (but an event nonetheless) coming from the northern stream wave. Looking at the new 12z Euro, that one places more emphasis on the GL low and presents more of an inverted trough precip scenario (snow) for the commonwealth and a late developing coastal low. Kind of an interesting run, cuz right before the northern stream really drops in, the southern stream wave escapes out ahead of that briefly forming a coastal off the FL/GA/SC coast. With that said, still pretty far out in terms of lead time and I don't feel that the Euro has necessarily been all that great this winter with the southern stream.

 

More significant cold comes in the wake of this pattern amplification and with that likely more emphasis on northern stream waves (clippers, etc). On that subject, one issue I've noticed this winter is the northern stream storm track really hasn't dropped enough to put us in really good shape for clippers so far this winter...instead taking lows well above PA and delivering only light snows to mainly the western/central counties. Ideally you want a clipper low dropping just under the PA border, and we really haven't seen anything close to that yet. We also haven't had any real major lasting intrusions of arctic air either, so hopefully a change in that will get us some of the more typical light-moderate events we usually see. 

 

Also have a bit of uncertainty about strength and lasting power of said cold as well. A strat-warming event and the associated splitting of the 10mb PV, -AO, etc) would argue for consistent cold intrusion into the mid-latitudes. A continued positive PNA would also help that cold center on our end of the country. However, the NAO looks to remain on the + side and the MJO looks to be mired near the circle or very weak phase 4 at best with the UK and Euro models insisting on it going solidly into the lousy 4 and 5 phases. Could imply a southeast ridge pushes back against a really deep cold intrusion if we indeed get into a higher amplitude phase 4-5 regime. It makes for quite a mixed signal really, so will be interesting to see what side ends up winning that battle. 

[r-ville]

Actually pretty good agreement on the global models that extend to the Day7 plus time period.

 

Looks like the GFS, in particular, wants to tap deep tropical moisture and bring it up with the coastal ~9th

 

 

 

Even WPC has "that look"

 

 

Nice Surface High in Canada - contrasts to a 50/50 low = funnel in the cold to counter the deep warmth riding up with the southern stream. Not sure if the 50/50 holds throughout (unlikely) but would set down decent shot of antecedent cold air mass.

[Itstrainingtime]

Has anyone else noticed that KMDT has been much colder than surrounding sites today?  With a breeze out of the northwest I am wondering if this is being influenced by the mountains of snow on city island creating a cold pool of air that is being channeled down the river to the ASOS site.

 

KMDT_temp_02012016.jpg

This morning when I left for work at 5:30am, I had a temperature of 32. By the time I drove 4 miles to the top of Chickies Hill it was 50! 

[Itstrainingtime]

* Active Pattern with Vacillating Temps throughout February *

 

Noon Monday, February 1:
Sunday's incredible high temperature of 56 degrees, along with bright sunshine, made for an almost Spring-like feel despite the lingering snow pack. Another dramatic surge of warm air is on the way for Wednesday, as a large storm tracks from Colorado to the Great Lakes. This storm will direct low-level wind flow from the Gulf of Mexico due north into the Commonwealth Tuesday night, and so temperature will likely rise overnight into the 50s by mid-morning Wednesday. The advance of this warm, moist air mass will help drive a period of rain late Tuesday night into Wednesday, before peeks of midday sunshine try to develop. While it will certainly be less sunny than Sunday, even an hour or two of passing sunshine, along with a brisk South wind, will be enough to lift temps to near 60 for the midday/afternoon hours. In case you're wondering, Wednesday's record high is 64° (1991)...a record that's in play if everything lines up just right. An approaching cold front will then trigger some late-day or evening showers and, perhaps, even an isolated T-storm.

The late week will turn seasonably chilly, but not unseasonably cold. Thursday is a transition day with highs in the low/mid 40s. Friday will be breezy and cool with a few flurries possible (especially in the mountains) and highs in the mid 30s. Right now, the weekend looks dry with partly sunny skies and high temps reaching the low/mid 40s.

For more than a week now, I've been eyeing the second week of February as a potentially stormy period as a split flow jet stream brings pressing cold air from the north and a storm or two from the Pacific across the south. It's much too early to get into details, but I do believe there's a storm to contend with during the Monday-Wednesday (Feb 8-10) period. Computer modeling is not trustworthy at this time, given that the key disturbances (for next week's complex storm) are still far out over the Pacific. Reading the pattern, however, I see two things that make me lean towards a "mixed precip" event here in Lancaster (or even rain ending as snow storm) rather than an all-snow storm. #1. Fresh cold air will be lacking across southeastern PA early next week...so rain (or wintry mix) is a better bet in the PA lowlands while snow is more likely in the mountains. #2. Jet stream ridging along the Northwest US coast favors an inland storm track in the East...perhaps roughly up the I-81 corridor. Obviously track and timing aren't things we can lock in for several more days, and so a plowable all-snow storm can't be rule out...but experience tells me that a mix/changeover event is more likely in southeastern PA. --Hörst

[r-ville]

18z GFS not only threatens the dates I've been mentioning, but even a few more. Including an actual GOM monster in its la la range (end of the run). Verbatim, we'd be looking at double digits in a ten day time period.

[r-ville]

 

* Active Pattern with Vacillating Temps throughout February *

 

Noon Monday, February 1:

Sunday's incredible high temperature of 56 degrees, along with bright sunshine, made for an almost Spring-like feel despite the lingering snow pack. Another dramatic surge of warm air is on the way for Wednesday, as a large storm tracks from Colorado to the Great Lakes. This storm will direct low-level wind flow from the Gulf of Mexico due north into the Commonwealth Tuesday night, and so temperature will likely rise overnight into the 50s by mid-morning Wednesday. The advance of this warm, moist air mass will help drive a period of rain late Tuesday night into Wednesday, before peeks of midday sunshine try to develop. While it will certainly be less sunny than Sunday, even an hour or two of passing sunshine, along with a brisk South wind, will be enough to lift temps to near 60 for the midday/afternoon hours. In case you're wondering, Wednesday's record high is 64° (1991)...a record that's in play if everything lines up just right. An approaching cold front will then trigger some late-day or evening showers and, perhaps, even an isolated T-storm.

The late week will turn seasonably chilly, but not unseasonably cold. Thursday is a transition day with highs in the low/mid 40s. Friday will be breezy and cool with a few flurries possible (especially in the mountains) and highs in the mid 30s. Right now, the weekend looks dry with partly sunny skies and high temps reaching the low/mid 40s.

For more than a week now, I've been eyeing the second week of February as a potentially stormy period as a split flow jet stream brings pressing cold air from the north and a storm or two from the Pacific across the south. It's much too early to get into details, but I do believe there's a storm to contend with during the Monday-Wednesday (Feb 8-10) period. Computer modeling is not trustworthy at this time, given that the key disturbances (for next week's complex storm) are still far out over the Pacific. Reading the pattern, however, I see two things that make me lean towards a "mixed precip" event here in Lancaster (or even rain ending as snow storm) rather than an all-snow storm. #1. Fresh cold air will be lacking across southeastern PA early next week...so rain (or wintry mix) is a better bet in the PA lowlands while snow is more likely in the mountains. #2. Jet stream ridging along the Northwest US coast favors an inland storm track in the East...perhaps roughly up the I-81 corridor. Obviously track and timing aren't things we can lock in for several more days, and so a plowable all-snow storm can't be rule out...but experience tells me that a mix/changeover event is more likely in southeastern PA. --Hörst

 

 

CAD signature may create more of a mixed ice to snow  than any plain rain to snow scenario, IMHO. But otherwise, it's good to see EH starting to verify that which the Bering Sea Rule and East Asia Rule have signaled for a while now.

[djr5001]

http://cms.met.psu.edu/sref/severe/2016/23Jan2016.pdf

 

a good read here on the recent snowstorm

[MAG5035]

http://cms.met.psu.edu/sref/severe/2016/23Jan2016.pdf

 

a good read here on the recent snowstorm

 

Def a good write-up, a lot of mention on the 850 wind anomalies that are a big part of major east coast storms and something that was consistently progged on the models leading up to the storm. No doubt it was big factor in aiding the widespread excessive 24-36"+ totals. Definitely quite something that they were on the same level as Hurricane Sandy. 

 

Speaking of which...I forgot to mention that they already have the NESIS rating out for the storm, which ended up to be a middle of the road Category 4 storm. It was good for 4th on the list of NESIS storms, with only the '93 and '96 blizzards and March 2,1960 beating it. 

[Blizzard of 93]

The 12z run of the Euro EPS ensemble mean had the best look for snow since the week before our recent blizzard. Next Tuesday, There is large cluster of lows that track under PA & hug the coast near the DelMarva region. The mean snow amount for most of CTP area is between 3-4 inches.

About 30 of the ensemble members bring most of us at least a few inches,& some members show 6+ inches. By the end of the 15 day run, the mean snow amount increases from 6 inches near the MD line to near 9 inches further north in PA.

[r-ville]

The 12z run of the Euro EPS ensemble mean had the best look for snow since the week before our recent blizzard. Next Tuesday, There is large cluster of lows that track under PA & hug the coast near the DelMarva region. The mean snow amount for most of CTP area is between 3-4 inches.

About 30 of the ensemble members bring most of us at least a few inches,& some members show 6+ inches. By the end of the 15 day run, the mean snow amount increases from 6 inches near the MD line to near 9 inches further north in PA.

 

The 12z run of the Euro EPS ensemble mean had the best look for snow since the week before our recent blizzard. Next Tuesday, There is large cluster of lows that track under PA & hug the coast near the DelMarva region. The mean snow amount for most of CTP area is between 3-4 inches.

About 30 of the ensemble members bring most of us at least a few inches,& some members show 6+ inches. By the end of the 15 day run, the mean snow amount increases from 6 inches near the MD line to near 9 inches further north in PA.

 

Have a feeling that the storm ~10th is capable of delivering more than just a few inches (as modeled right now). IIRC the Euro is a QPF stingy model in the medium range.

 

984mb at the Delmarva sweet spot. Big question is, "can it stay there as modeled?"

 

[r-ville]

[Blizzard of 93]

I agree R-vile, the 0z Euro Op that you posted above shows the low hugging the coast of the

Southern tip of Delaware. Somehow, verbatim it only gives MDT 4 inches of snow. With a low in that spot, the precip rates & coverage would be much greater. The low forms in NC, & strengthens as it heads northeast, which is a great spot for most of CTP. Let's hope this track holds in future runs, & then we would be in business !

[pasnownut]

This past few days has been nothing short of maddening with the models trying to latch onto what's going on and what bundles of energy to play with.  I know they typically struggle to catch on, and in a season of back an forth with warm/cold...I need dramamine.

 

I hope it holds, and that the AO/NAO finally go neg and stay there for a while.  This could be our shot.

 

Nut

[heavy_wx]

I agree R-vile, the 0z Euro Op that you posted above shows the low hugging the coast of the

Southern tip of Delaware. Somehow, verbatim it only gives MDT 4 inches of snow. With a low in that spot, the precip rates & coverage would be much greater. The low forms in NC, & strengthens as it heads northeast, which is a great spot for most of CTP. Let's hope this track holds in future runs, & then we would be in business !

 

That system is basically a clipper that redevelops offshore of the mid-Atlantic. As depicted, the system doesn't develop a significant cold conveyer belt until it reaches New England. This evolution makes it difficult to produce significant precipitation as far west into central PA as would a mature coastal low at the same location. Of course, this potential system is still 7+ days out so specific operational runs are going to be of limited value for the next few days.

[canderson]

Heavy rain and 60 just murders snowpack. I'll probably not have anything left at home except a few larger piles tonight.

[NortheastPAWx]

Hey, at least rain events don't fringe us