3 Snows During The Christmas Week

Christmas Eve, the day after Christmas, and now it is looking as if there will be yet another round of winter precip in the form of accumulating snows Friday night into Saturday.  Before we jump ahead to the weekend event, let's look back at what just transpired during the last 24 hrs.  At my humble abode, I measured 3.4 inches of snow prior to the changeover to freezing rain and ultimately some plain rain well after sunset.  The total amount of precip was 0.72"; therefore, roughly half of the precip fell as snow.  I believed that the primary low and its overrunning precip would hold longer than it did.  Once the energy transfer took over, so did the upper air support for the precip that did come fast & furious for a time.  Look at the obs at KCXY in terms of visibility...4 hrs of less than 1 mile vis...and visibilities were far less during the height of the snowfall Wed afternoon!

Here is the storm now as seen from space...Note the cold air rushing out over the Gulf creating the clouds off the TX and LA coasts!  Lots of StratoCu for us here in PA today on strong NW winds!

Here is another graphic with the isobars/pressures overlaid...

And the current temps across the CONUS...note that the 32°F isotherm traverses PA...quite cold in the plains of O Canada!

After yesterday's snow, take a look at the snow covered US...

...and compare the map above to the map below from last year at this time!

And more snow will be added to the CONUS by this weekend as yet another disturbance will track from the southern plains towards the New England coast.  The runs have been getting closer and closer to the coast, but we are still a bit away from the onset of the event and all the "players" are yet on the continent for the models to properly ingest...Here is the Euro...it's a nice moderate snowfall for KMDT Sat am...

What is interesting is that the 500 mb lowest pressures of the Euro ensembles are in a quite favorable area for even greater deepening of a surface low that would impact southern PA to an even greater extent than the operational indicates.

Here is the Ukie's take...

And the GFS...a bit further SE...but the ensembles again argue for a bit closer in towards the continent...

Here are the ensembles...the lowest heights are again in a favorable position to spin up a nice storm for southern PA...and the trough is somewhat negatively tilted...

Here is the operational's take on the vorticity in the middle levels...if that vort max can become less sheared and more "phased" a stronger storm is in the cards for Sat am...note where I circled in RED...

OK...I've bored y'all enough...so if you take a stroll outside anytime this week...keep this Christmas-time ditty in mind...I think Annie makes most songs sound great...enjoy!

Smitty

AA:  Looking at yet another snowfall for Friday night into Saturday midday...then getting "brutally" cold for the New Year's celebrations!

Merry Christmas

Just like Bing sang about, many around KMDT will awaken to a beautiful snow covered landscaped around the Harrisburg area!  I was not at home to witness the onset of the snow, but it did come just prior to sunset and fell rather steadily as per the obs at KCXY for ~4 hrs.  Take a look at how the visibility was rapidly decreased once the snow began to fall.  The roads in the Lancaster area quickly became snow covered and slick as many cars slid off the roadway as I witnessed driving to Christmas Eve services!  Not good...I was wondering where PENN DOT was...this was not a secret...

Here is a quick map of where the snow accumulated across the Lower Susquehanna Valley as reported to the NWS in State College.  Not the highest amounts shaded right across the central part of York County with a bulls-eye right at my humble abode!  When I returned from Christmas Eve services, there was measured 2.5 inches on the ground...so I'm sure a reading of closer to 3" was accurate nearer to the ending of the heaviest accumulating snows!  Not too shabby for Christmas Eve in these parts...!

And there is more on the way...but the modeling, although increasing in its consistency, is still waffling back and forth on many issues from exact surface low placement to upper air flow downstream and upstream, to the amount of warm ocean air that intrudes ~1 mile above the surface.  All of these factors lead to a rather difficult and challenging forecast.  Over the years, I've seen these synoptics usually do the following in these parts:

1.  Begin as snow...and snow rather heavily at the start...
2.  Slowly mix with and then change to sleet and rain...
3.  End as a brief period of accumulating snow before getting blustery and very cold...

I believe this will once again be the scenario in these parts.  There will be an extremely tight gradient as well with the heaviest snow; places like Blaine, Perry Co may receive 12" while KMDT only 4-6", and Philly just 1".  If you are looking for the heaviest snows with this storm, I feel that State College, Dubois, Clearfield, Renovo, Lock Haven, etc are in the "sweet spot" as the upper levels will struggle to get above 0°C and copious amount of precip will fall as snow.  The latest GFS shows this rather narrow gradient in terms of accumulated snows...

This is a tricky forecast.  I just wished there was a stronger high pressure in southern Quebec!  Not that 1033 mb is a small high...just a few mb greater in terms of its air's density would make me feel a bit more confident in forecasting a major event for KMDT!

As I've been touting for the last several days now, we are looking at a plowable and possibly a high impact snow event later Wed into Thursday.  The other thing that makes me just a tad hesitant is that the 00Z Euro trended just a smidgen warmer overnight...but the GFS has been trending colder with each of its last several (6?) runs...so we will see what we will see.

And by the way there is potentially more fun and games waiting in the wings for this upcoming weekend!  We need to get closer to that event once the atmosphere exerts its energy potential the next few days...

So I wish y'all a very Merry Christmas...and I truly appreciate you taking the time to reads these posts, as I try to inform you of things the TV guys and the NWS State College may not be...I will leave you with this....Enjoy!

Merry Christmas y'all!

Smitty

AA:  Looking at a snow to rain back to brief snow event Wed-Thurs; then another potential storm over the weekend.  Getting MUCH colder next week!

Cold to Follow...?

Not sure about the upcoming MAJOR storm this Wed-Thurs, but one thing I am fairly confident about and that the anomalous cold that will greet us on the the 1st few days of the New Year!  I for one...if I were going to be hanging outside anywhere in the northeast USA to usher in the New Year,... be dressed for winter's harshest cold!  Here is the 5 day anomalies centered on New years Day!  It is a cold graphic....no doubt!  This is in degrees C...so it is essentially -10°F from the norms!  That's darn cold!  If there is any snow pack, it will be much colder than indicated!

The Euro and the GFS both promote a cold and relatively dry pattern as per the 500 mb upper air pattern as seen below...

And the US generated model of the Climate Forecast System Version 2 suggests that January will be severely cold!

So I am fairly confident of cold weather hanging tough here in the month of January...and the pattern of storms will be prevalent across the CONUS...but how much the cold dome of high pressure can be attacked by the southern stream will be interesting.  This could be a January where many will want an early spring as the severity of winter weighs on many.  It could also be a January that is simply dominated and overwhelmed by NW flow; cold and dry.  But cold should rule the month of January!  We will see what we will see...

As for the Wed-Thurs system, WISH-CASTING...as opposed to forecasting...I'm rooting for the Japanese model...this is a major hit!  KMDT would be looking at 12-18" if this would verify!  Bring it!

OK...I'll leave y'all with this...and I'll try to update tomorrow morning once the Euro rolls in...(Check Twitter...) and before I spend my time away from the models, climatology, and meteorology in general to spend with family and friends...

Merry Christmas, Happy Hanukkah...or whatever you so desire to celebrate.  For me, I celebrate the birth of the Christ child...or as the lyricist wrote years ago...my favorite Carol...

What child is this, who, laid to rest,On Mary's lap is sleeping?Whom angels greet with anthems sweet,While shepherds watch are keeping?This, this is Christ the King,Whom shepherds guard and angels sing,Haste, haste to bring him laud,The Babe, The Son of Mary!...

I will also link to this since it is one of my favorites...

Once again, MERRY CHRISTMAS!

AA:  A cold January looks to be in the cards...

Post Christmas Wx Uncertainty

With the threat of a major nor'easter 3-4 days away, there remains a tremendous amount of uncertainty within this time frame.  Quickly here before I receive some divine intervention with my addiction with the wx, I will show you the Euro Model for the path of this storm...unfortunately, the "free" Euro model output is for only 24 hour increments and cannot really depict where the exact path of the LOWS will track.  With that said, there will be 2 lows...the primary traveling up towards KPIT with a secondary low forming as energy is transferred towards the natural baroclinic zone of the coast/ocean interface.  Here are the 3 Euro positions...

Christmas Night

Wednesday night

 Thursday Night

Note in the Wed. night graphic, you can see centers of low pressure; one in WV and one forming over in the coastal plain of VA/NC.  The sooner the secondary forms, the more likely for a major snowfall.  IT IS WAAAAAAY TOOOOO EARLY to determine an exact path or precip type for KMDT with this storm.  I do feel that in excess of 1" will fall from the skies...the million dollar question WHITE OR WET???  Not sure...I do like the high pressure to the north on all of the modeling.  I will not bore you with the 500 mb map now, but there is adequate (not very strong what I like to see) confluence over the province of Quebec.  This supports cold air funneling southwestward towards PA and helping hold the cold in place.  The synoptics of this pattern are very complicated with the extreme cold just to the NW of the CONUS and the anomalously warm oceans to our east.  Many of you will see forecasts for rain...that is because the GFS is the furthest west of all of the global modeling and as of this writing...AN OUTLIER!  It does develop a secondary storm, but too far north and east to make it snow much in these parts.  Here it is...

GFS Model

As for Christmas Eve snow, we are still looking at a skiff of ~1-2" before changing to very light freezing drizzle by early Christmas morning.  A white frosting SHOULD greet anxious youngsters and adult winter wx lovers alike!  But the big ticket item is most certainly Wed-Thurs...and I'll try to keep y'all updated as best as I can.  

Follow me on Twitter...if you so desire!  It is very quick and easy for me to quickly post a graphic or quick statement concerning the wx.  Heck, I can even post while pumping out some cardio on the arc trainer.  In fact, it makes the workout go a bit quicker!  If you have a smart phone, Twitter is extremely easy to utilize.  No...you do not need to tweet!  Just get a screen name and a valid email address...and you can access Twitter!  Do it...it's perfectly legal to be a Twit!  And I think most of you will be pleasantly surprised as to what you QUICKLY find out!

OK...off to receive divine intervention.  Let me leave y'all with this wonderful ditty...

Merry Christmas!

Smitty

AA:  Nice Sunday, increasing clouds and cold Christmas Eve with light snow arriving late in the day.  Cold and mostly cloudy Christmas Day awaiting the bigger storm for Wed-Thurs.  By the way, another for the weekend...different story for a different day!  Merry Christmas my friend!