Pittsburgh/Western Pa Weather

[whamcity]

I am scarred from the last event. Some of this still suggests some mixing. 

[KPITSnow]

Nws basically says nothing about the event in their discussion. Probably wants to downplay after the last event

[Rdd9108]

Lets wait and see the GFS and NAM keep on trending while the Euro holds its ground. Although the amounts on the snowfall map maybe quite overdone.

[Mailman]

I can't say that I'm buying into this DT special....

[whamcity]

Almost no weather media outlets are saying anything other than a sloppy, slushy mess. 

[RitualOfTheTrout]

How about the totals for the whole event? Euro said 10-12. Im interested to see if these models are finally getting a clue about the intense cold coming into the CONUS.

I'd be skeptical of those totals for several reasons but especially because I don't think those take into account any melting that would take place if say we get 4 inches of snow Sunday night then it rains all day Monday and melts it away then we get 4 more on Tuesday for example. We may end up getting 3 2-4 inch events but at the end of the storm train it seems unlikely, at least at this point, that you will go out in your yard with a yard stick and meausre 12 inches.

[RitualOfTheTrout]

Also, be careful reading on the other subforums. The Sunday-Monday event will rely heavily on CAD with a 1035-1040 high to the north with a storm cutting to the west. Unfortunately we are on the wrong side of the Apps for CAD. It may end up being 36 and rain here, while areas in southern VA are in the upper 20s.

[north pgh]

12z Nam coming in a little colder and still showing 5 inches.

NWS now calling for 1-2 Friday.

I think if the GFS comes in colder we may see NWS up to a 2-4 inch scenario Friday assuming we go to snow early.

[Rdd9108]

Ill take 2-4 and take off running. So whats the idea with the next waves. Will there be less chance of mixing?

[KPITSnow]

Gfs is quite a bit colder.

Two big threats in November and early December. When was the last time that happened?

[RitualOfTheTrout]

Ill take 2-4 and take off running. So whats the idea with the next waves. Will there be less chance of mixing?

Friday-Saturday will have rain changing to snow, with what looks like our best chance at accumulating snow. Then Sunday-Monday will have snow quickly changing to a wintry mix to rain. Maybe even some zr Sunday night. It looks like most of the precip though will be rain, at least based on today's 12z GFS.

 

I don't see how we would avoid mixing in the second storm. Even if the cold air can hang on longer, or the high can pump cold air in longer, it would likley mean more sleet and zr rather than snow. There isn't even the weenie hope of a fater transfer, as this is not a Miller-B, GFS drives the low up into Canada.

[colonel717]

 Reduced: 62% of original size [ 1024 x 768 ] - Click to view full image

 

 

 

[north pgh]

NATIONAL WEATHER SERVICE PITTSBURGH PA
343 PM EST WED DEC 4 2013

.SYNOPSIS...
RAIN WILL SPREAD OVER THE REGION ON THURSDAY AS A COLD FRONT
SLIDES TOWARD THE REGION. AS THE COLD FRONT PASSES...RAIN WILL
CHANGE TO SNOW ON FRIDAY.

&&

.NEAR TERM /THROUGH THURSDAY/...
LOW PRESSURE WILL DEEPEN AS IT MOVES FROM ILLINOIS NORTHEAST INTO
CANADA. OUR REGION WILL REMAIN IN THE WARM SECTOR
OVERNIGHT...AND SOUTHERLY FLOW WILL ALLOW OVERNIGHT LOWS TO REMAIN
WARMER THAN NORMAL DAYTIME HIGHS FOR EARLY DECEMBER. THE BULK OF
THE RAINFALL SHOULD REMAIN TO THE WEST OVERNIGHT...WITH THE FRONT
CROSSING THROUGH THE REGION THURSDAY. WITH THE FRONT ARRIVING LATE
IN THE DAY...TEMPERATURES WILL RISE INTO THE UPPER 50S AND 60S.

&&

.SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/...
THE FRONT WILL ESSENTIALLY STALL OUT JUST TO THE EAST OF THE
FORECAST AREA THURSDAY NIGHT INTO FRIDAY...WITH MULTIPLE
SHORTWAVES RIDING ALONG THE FRONT TO THE NORTHEAST. ONE SHORTWAVE
IS LIKELY THURSDAY NIGHT...WITH ANOTHER MOVING UP THE FRONT ON
FRIDAY. MANY LOCATIONS WILL PICK UP HALF AN INCH OF RAINFALL
THURSDAY NIGHT.

AS THE FRONT PASSES...TEMPERATURES WILL TUMBLE SOME 20 TO 25
DEGREES THURSDAY NIGHT. ON FRIDAY...TEMPERATURES MAY NOT EVEN RISE
FROM THE OVERNIGHT VALUES. A CONCERN WITH THE FRONT IS THAT WHILE
TEMPERATURES WILL SIGNIFICANTLY DROP AT THE SURFACE...A WARM LAYER
COULD REMAIN ALOFT...BRINGING THE CHANCE FOR MIXED PRECIPITATION.
HARD TO PIN DOWN EXACTLY HOW THIS PRECIPITATION TYPE EVOLUTION
COULD OCCUR...BUT FOR NOW THE FORECAST HAS RAIN CHANGING OVER TO
SNOW...WITH A FEW HOURS OF SLEET AS A POSSIBILITY AS WELL. IN
ADDITION...FRIDAY AFTERNOON IS WHEN THE GREATEST AMOUNT OF
PRECIPITATION IS EXPECTED TO FALL...RIGHT AS TEMPERATURES WILL BE
CRITICAL FOR DETERMINING WHAT TYPE OF PRECIPITATION IS FALLING.
THAT TIME PERIOD COULD FIND RAIN ACROSS THE SOUTH...WITH HEAVY
SNOW FALLING TO THE NORTH. SNOWFALL TOTALS HAVE BEEN BUMPED UP BY
A COUPLE OF INCHES. THE FRIDAY AFTERNOON AND FRIDAY EVENING TIME
PERIOD WILL NEED TO BE CLOSELY MONITORED DURING FUTURE FORECASTS.

AFTER FRIDAY EVENING PRECIPITATION SHOULD RAPIDLY MOVE OFF TO THE
EAST...WITH JUST A SLIGHT CHANCE OF SNOW PERSISTING ON THE RIDGES
SATURDAY MORNING. ALTHOUGH THE FLOW WILL BE FAVORABLE FOR LAKE
EFFECT OR UPSLOPE SNOW...PROFILES JUST APPEAR TO BE WAY TOO DRY
WITH INVERSION LEVELS ONLY REACHING ABOUT 3000 FT. HAVE KEPT
MOSTLY CLOUDY SKIES IN THE FORECAST...BUT LITTLE PRECIPITATION.
HIGH TEMPERATURES ON SATURDAY WILL BE ABOUT 10 DEGREES BELOW
NORMAL.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
MORE ACTIVE WEATHER IS EXPECTED EARLY NXT WEEK AS PTN OF CNTRL
CONUS TROFG AND WRN ATLANTIC RIDGING MAINTAINS OVRALL SWLY FLOW
OVR THE UPR OH REGION. ECMWF AND GFS INDICATE RAPID EMERGENCE OF
LOW PRES FM THE LWR MS VALLEY TO THE GREAT LAKES ON SUNDAY AND
MONDAY.

AS THESE MDLS HAVE CONSISTENTLY SHOWN A TRACK WEST OF THE
IMMEDIATE AREA OVR THE LAST CPL OF DAYS...HAVE ACCEPTED A WARMER
WPC SOLN AS IS TYPICAL OF THAT WINTER PATH. UNFORTUNATELY...THE
WARM ADVCTN ON THE ERN FLANK OF THE LOW...COMBINED WITH COLD AIR
ENTRENCHMENT REINFORCED VIA NEW ENGLAND HIGH PRES...MAY SPPRT
PROLONGED FREEZING RAIN FOR PART OF THE AREA. FOR NOW...HAVE OPTED
FOR A MORE AGGRESSIVE PCPN PHASE CHANGE FM SNOW AND FREEZING RAIN
TO ALL RAIN AS SUNDAY NGT PROGRESSES. A HAZARDOUS WEATHER OUTLOOK
WILL ALSO BE INCLUDED AND MONITORING WILL CONTINUE.

OTHERWISE...COLDER AND DRIER AIR WL BE SHUNTED OVR THE UPR OHIO
REGION IN THE WAKE OF THAT SYSTEM...WITH TEMPS AND POPS FORECAST
USING A COMBO OF WPC AND MOS GUIDANCE.

&&

[CoraopolisWx]

Well, here we go again.

 

Last week it was the storm being too weak, that hurt us.

This time a weaker storm won't be the worst thing, as a stronger central low could pull more warm air into the region.

 

The late week storm setup is usually pretty good for us, as we saw in mid November.

 

This upcoming pattern is something we might see in late January/early Febuary, not so much early December.

[RitualOfTheTrout]

Well, here we go again.

 

Last week it was the storm being too weak, that hurt us.

This time a weaker storm won't be the worst thing, as a stronger central low could pull more warm air into the region.

 

The late week storm setup is usually pretty good for us, as we saw in mid November.

 

This upcoming pattern is something we might see in late January/early Febuary, not so much early December.

Judging from the 18z, it looks like the Sunday-Monday storm is weaker than 18z, or maybe even popping a secondary? I don't have time to treally look closely but if that trend continues more frozen would seem likely.

[Rdd9108]

Is it safe to say this looks like a 2-4 event for the whole event max? Its only December but Im already starting to hate how the heavier snows almost always fall to the north.

[CoraopolisWx]

Is it safe to say this looks like a 2-4 event for the whole event max? Its only December but Im already starting to hate how the heavier snows almost always fall to the north.

From what I saw the 0Z Nam, and to an extent the GFS seem to slow down the heaviest precip a bit, and allow more cold air ahead of it.

 

However considering the setup, 2-4 wouldn't be that bad.

[Rdd9108]

What kind of drugs is the Euro on that continues to snow 6-9 on the non high rez maps?? Is the Euro coming in colder than the other models.

[RitualOfTheTrout]

What kind of drugs is the Euro on that continues to snow 6-9 on the non high rez maps?? Is the Euro coming in colder than the other models.

Take any snow map with a grain of salt, and a non high res with a lump of salt regardless of the model spitting them out, especially in a tough to forecast setup like what we will see tomorrow and Sudnay.

 

2-4 for tomorrow into Saturday seems reasonable, although the NWS seems very bareish right now given the approach of the dry slot and continued WAA in the mid levels. Hopefully todays runs come in a little colder so we don't waste all our qpf on rain. 

[JamieOber]

Take any snow map with a grain of salt, and a non high res with a lump of salt regardless of the model spitting them out, especially in a tough to forecast setup like what we will see tomorrow and Sudnay.

 

2-4 for tomorrow into Saturday seems reasonable, although the NWS seems very bareish right now given the approach of the dry slot and continued WAA in the mid levels. Hopefully todays runs come in a little colder so we don't waste all our qpf on rain. 

If the snowmap is from WxBell, take it with a lump of cyanide; it'll save the disappointment. Those maps are horrible.

[colonel717]

Looks like the 12Z NAM is a whiff on snow for WPA.  Snow West and North.

[north pgh]

Looks like the 12Z NAM is a whiff on snow for WPA.  Snow West and North.

Yes according to this model we get over 1/2 inch of freezing rain and sleet and 1 inch of snow. Much will depend on when the switch over happens. If we change quicker we can still get more snow.

[Rdd9108]

I feel like in the case of this big arctic high that temperatures can be something that the models can't get a perfect grasp on. Is that correct?

[Burghblizz]

12z GFS looks colder for first event. Could be just be weenism because i just snuck a quick peek at work.

[RitualOfTheTrout]

12z GFS looks colder for first event. Could be just be weenism because i just snuck a quick peek at work.

No its definitely colder than the NAM, or the front pass through a bit faster, however you want to look at it. Both models show the surface cooling faster than the mid levels so some sleet and zr are good possibility. Just eyeballing from the graphics the GFS shows probably at least .3-.5 as snow outside of maybe extreme SW PA.

[Rdd9108]

So i know its one of those things that will be impossible to predict, but Ill be out on the roads tomorrow night. How much around Wexford should I look for. O

[Burghblizz]

Its been showing 6"+ but dont think anyone was buying it due to boardline temps. This run was colder....or like you said maybe faster....so it looked like more precip as snow. But again, just a quick glance by me and havent seen output

[RitualOfTheTrout]

So i know its one of those things that will be impossible to predict, but Ill be out on the roads tomorrow night. How much around Wexford should I look for. O

I'd be curious to know how pavement temperatures are going to cool. On one hand its in the 60s today, but on the other we are progeed to cool into the upper 30s tonight with some more cold rain. Is that enough to offset todays warmth? I'd be skeptical any zr would accumulate on pavement and concrete tomorrow, but as the temps drop and we switch to snow, if you happen to get a heavy burst it could still get icy fast I would think.

[RitualOfTheTrout]

Its been showing 6"+ but dont think anyone was buying it due to boardline temps. This run was colder....or like you said maybe faster....so it looked like more precip as snow. But again, just a quick glance by me and havent seen output

I still think at this point, gauging off the GFS 2-4 looks like a safe call. If things end up colder as we get closer then who knows, maybe 4-6 wouldn't be that far fetched?

[north pgh]

No its definitely colder than the NAM, or the front pass through a bit faster, however you want to look at it. Both models show the surface cooling faster than the mid levels so some sleet and zr are good possibility. Just eyeballing from the graphics the GFS shows probably at least .3-.5 as snow outside of maybe extreme SW PA.

You are correct. It looks like going below freezing will not be the issue but the warm air aloft. I think that we will lose 5 or 6 hours of snowfall to sleet and freezing rain tomorrow afternoon. The heavier snow will be just to our west and Northwest like the last storm. If things shift a tad further east we could get that changeover faster and get more snow. I haven't seen the numbers yet for GFS  but the models seem to be locking in.

Looking at the CCEM we are still right on the edge but mostly a mix before ending as snow.

 

http://collaboration.cmc.ec.gc.ca/cmc/cmdn/pcpn_type/pcpn_type_gem_reg.html