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Pittsburgh PA spring 2017


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1 minute ago, Burghblizz said:

But likely over doing it....still a little outside its range. Although it's advertisting a foot creeping in to allegheny county, I also doubt you see the widespread 24" plus totals to the east

It was more about the trend west than anything.  Seems a lot of guidance supporting west trend

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PROBABILISTIC HEAVY SNOW AND ICING DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 510 PM EDT SUN MAR 12 2017 VALID 00Z MON MAR 13 2017 - 00Z THU MAR 16 2017 DAYS 1-3... ...MID ATLANTIC TO THE NORTHEAST... WHILE DIFFERENCES IN THE DETAILS REMAIN...FORECAST CONFIDENCE CONTINUES TO INCREASE THAT LOW PRESSURE DEVELOPING ALONG THE SOUTHEAST COAST MON EVENING WILL DELIVER WIDESPREAD MODERATE TO HEAVY SNOWS TO PORTIONS OF THE INTERIOR MID ATLANTIC AND THEN ACROSS THE NORTHEAST AS IT TRACKS NORTH ALONG THE COAST TUE-WED. GUIDANCE SHOWS MID-LEVEL ENERGY EMANATING FROM THE PACIFIC DIVING SOUTHEAST INTO THE SOUTHEASTERN U.S. MON EVENING WHERE IT IS FORECAST TO BEGIN PHASING WITH SUBTROPICAL ENERGY LIFTING OUT OF THE NORTHERN GULF OF MEX. BY EARLY TUE THIS PHASED ENERGY IS EXPECTED TO BEGIN LIFTING NORTH...ASSUMING A NEGATIVE TILT AHEAD OF NORTHERN STREAM LOW CLOSING OFF OVER THE UPPER GREAT LAKES. MODELS SHOW THE SHORTWAVE LIFTING RAPIDLY TO THE NORTH ALONG THE MID ATLANTIC TO THE NORTHEAST BY LATE TUE...GRADUALLY PHASING WITH THE NORTHERN STREAM LOW AS THE LOW DRIFTS EAST. AT THE SURFACE...LOW PRESSURE ORGANIZING ALONG THE SOUTHEAST COAST MON EVENING WILL BEGIN TO RAPIDLY DEEPEN AS IT TRACKS NORTH ALONG THE MID ATLANTIC COAST EARLY TUE BEFORE REACHING THE SOUTHERN NEW ENGLAND COAST BY TUE EVENING. MOST OF THE GUIDANCE SHOWS THE SURFACE LOW PRESSURE DROPPING INTO THE UPPER 970S AS IT APPROACHES EASTERN LONG ISLAND AND SOUTHEASTERN NEW ENGLAND TUE AFTERNOON-EVENING. AS HAS BEEN THE CASE...GUIDANCE STILL DIFFERS ON THE DETAILS OF THE LOW TRACK...WHICH OF COURSE HAS SIGNIFICANT IMPLICATIONS TO THE SNOWFALL FORECAST AS WELL. FORTUNATELY THROUGH 12Z TUE...THE LATEST DETERMINISTIC GUIDANCE IS FAIRLY WELL-CLUSTERED...WITH A LOW CENTER OFF OF THE DELMARVA COAST. THEREAFTER THE SPREAD INCREASES...WITH THE GFS MOVING TO THE PROGRESSIVE AND EASTERN EDGE OF THE GUIDANCE...WITH THE ECMWF/UKMET/NAM CLUSTERED FURTHER TO THE WEST AS THE LOW MOVES ALONG THE NORTHEAST COAST LATE TUE INTO WED. WITH THE GUIDANCE IN GOOD AGREEMENT UP TO THAT POINT...WPC PREFERRED A COMPROMISE BETWEEN THE ECMWF AND THE GFS INTO DAY 2 (ENDING 00 UTC WED)...WHICH WOULD SUPPORT MODERATE TO HEAVY SNOW ALONG AND TO THE NORTH AND WEST OF THE I-95 CORRIDOR FROM DC TO COASTAL MAINE. MARGINAL LOW LEVEL/BOUNDARY LAYER TEMPS ARE LIKELY TO KEEP AMOUNTS IN CHECK FURTHER TO THE SOUTH AND EAST. OF COURSE ANY SHIFT IN THE SURFACE LOW TRACK COULD HAVE SIGNIFICANT IMPACTS ON WHERE THIS TRANSITION ZONE SETS UP. FOR THE DAY 2 PERIOD...WPC PROBABILISTIC GUIDANCE SHOWS A MODERATE RISK FOR 24-HR ACCUMULATIONS OF A FOOT OR MORE EXTENDING FROM N-CENTRAL MD TO THE SOUTHERN MAINE COAST. IN ADDITION TO THE STRONG UPPER FORCING...LOW TO MID LEVEL FRONTOGENESIS IS EXPECTED TO SUPPORT THE POTENTIAL FOR HEAVY SNOWFALL RATES. BY DAY 3 (ENDING 00 UTC THU)...HEAVIEST SNOW ACCUMULATIONS ARE EXPECTED TO CENTER ACROSS NORTHERN NEW ENGLAND...PARTICULARLY ACROSS NORTHERN MAINE WHERE PROBABILISTIC GUIDANCE SHOWS A MODERATE RISK FOR ACCUMULATIONS OF A FOOT OR MORE. IN ADDITION TO THE SYNOPTICALLY DRIVEN SNOW...STRONG NORTHERLY TO NORTHWESTERLY SNOW ON THE BACKSIDE OF THE SYSTEM IS EXPECTED TO ENCOURAGE DEVELOPING LAKE-EFFECT SNOWS...BOLSTERING AMOUNTS ACROSS PORTIONS OF WESTERN NY. WITH THE SPREAD INCREASING AND THE GFS MOVING TOWARD THE EASTERN EDGE OF THE GUIDANCE ENVELOPE...WPC PREFERRED A SOLUTION MORE IN LINE WITH THE ECMWF. BUT WITH THE ECMWF MOVING TOWARD THE SLOWER EDGE OF THE GUIDANCE...INCORPORATED SOME OF THE EC ENSEMBLE MEAN INTO THE PREFERRED SOLUTION AS WELL. ...UPPER MS VALLEY/UPPER GREAT LAKES... THE AFOREMENTIONED MID-UPPER LEVEL PACIFIC SHORTWAVE IS EXPECTED TO DROP SOUTHEAST FROM THE NORTHERN PLAINS INTO THE MID MS VALLEY AS THE PREVIOUSLY NOTED NORTHERN STREAM TROUGH BEGINS TO DROP INTO THE UPPER GREAT LAKES. AMPLE LOW LEVEL THETA-E ADVECTION IS EXPECTED TO HELP SUPPORT LIGHT TO MODERATE SNOWS SUN NIGHT INTO MON ACROSS PORTIONS OF SOUTHERN MN...IA TO LOWER MI...NORTHERN IND AND NORTHWEST OH. HEAVIEST AMOUNTS ARE EXPECTED TO CENTER ACROSS EASTERN IA INTO SOUTHERN WI AND NORTHERN IL...WHERE WPC PROBABILISTIC GUIDANCE SHOWS A SLIGHT RISK FOR SNOW ACCUMULATIONS OF 8-INCHES OR MORE FOR THE DAY 1 PERIOD (ENDING 00 UTC TUE). THE PROBABILITY OF ICE ACCUMULATIONS OF 0.25 INCH OR MORE IS LESS THAN 10 PERCENT.

 

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8 minutes ago, Mailman said:

Not sure if that rule applies for this time range.

I was thinking the same thing, but can't hurt to have it close to the coast like that. To bad the storm isn't taking a more NNE trajectory rather than ENE from that point. If it tracked over the PA\NJ boarder that would probably get some better snows back our way.

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6 minutes ago, RitualOfTheTrout said:

I was thinking the same thing, but can't hurt to have it close to the coast like that. To bad the storm isn't taking a more NNE trajectory rather than ENE from that point. If it tracked over the PA\NJ boarder that would probably get some better snows back our way.

Right....or stall/slowly move through that general latitude, or even retrograde slightly. That's a common thing seen in our bigger storms. That's where the 500 closed low always helps. If the storm scoots off to the ENE, so typically go the heavier snows.

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