Cold & Dry

How do those 2 words greet you this cold Thursday morning?  With one of the colder mornings in recent times...and it's about time...people living in the eastern US face the prospect of watching an extremely deep trough pass through our part of the continent without any atmospheric fanfare, save for some feisty lake effect snows in the lee of the "warm" lakes.  As I type this, the 5 am obs at KCXY is 23ºF with a dew point of 13ºF.  What makes that somewhat impressive in light of our recent above normal temps is that the air is still moving with a W wind of 5 mph!  It might drop to the coldest temp yet this winter (19ºF) prior to our 7:30 am sunrise!

Just take a look at our near year end climatogram for Harrisburg.  73 inches+ of precip is unreal.  And also note how the temps this December have been up in the "pink" band of above normal in terms of temps.  Only a small amount of the temp has spent any time down in the "blue"...and for lovers of the winter wx, that gives us the blues!

But that will change, both in the precip department and the temperature department as an Arctic front appears to be scheduled to cross our area on/about Sunday afternoon.  Once we get into the true arctic origin air (with dew points in the single digits and below 0ºF), it appears that most of next week will be featuring reinforcing shots of arctic air with little in terms of precip, save for some flurries that make it SE of the mountains.  Take a look at the Euro for next Monday evening...that is one deep trough!

And being supported by a vast arctic high located from Quebec down to SC...that map below screams of clipper type systems only affecting us here in PA...

As does the 500 mb vorticity map for the middle of next week...there is simply no modeled energy "upstream" so to speak as shown by the yellow patches of vorticity (atmospheric spin or energy)...again a bit disheartening as the modeling is squelching any idea of storm system developing in the flow.

The storms are developing out over the Atlantic as shown by both the Euro (storm well out to sea)...

and the Canadian...Yesterday, both the Euro and the Canadian had storms much closer to the coast.  Today, they have trended these storms even further out to sea.  There is still a chance of a weaker system developing along the natural baroclinicity of the cold land/warm ocean interface, but that is frankly grasping at straws for snow-lovers here in the eastern US.

 One thing, however, is that the snow guns will be going full bore as the arctic air will allow for decent artificial snow making at places like Roundtop.  The other snow guns will be downwind of the Great Lakes as shown by the snowfall graphic below.  Note the accumulations in the favored snow belts around the lakes...

Compare that to the initialization of the model seen below...also note the glacier beginning to form up in Quebec above...

So there you have it.  Cold and dry.  Nothing fancy. I will, however, issue a static electricity warning as the lower dew points will support speedy electrons traveling from people to ground at the most unsuspecting times as well as the most predictable ones!  I hate sliding out of my car and getting lit up with what seems to be at least 1,000 Volts!  But as my E&M prof at PSU reminded us so often, "it's not the voltage that will kill you, it's the amperage!".  Heck, all I know is that I HATE STATIC ELECTRIC POTENTIAL, and next week will be very conducive to generating ample electric potential between human and everything!

Have a great Thursday...and I'll keep looking for a storm to develop on the arctic front!

Smitty

AA:    Coldest air of the winter next week...very little if any precip to accompany it however....but plenty of static electricity will!  Beautiful baby my friend! Glad everyone is healthy & your kids get their looks from their mom!

Exhilarating Euro

Just a very brief post to keep everyone in the loop concerning the deepening trough for next week by a severely buckling jet stream into the eastern US.  I will use all ECMWF maps as they tend to do best at this time range; although sometimes just a bit overdone.  I'll cut right to the chase with the first map, why leave anyone hanging right?  This simply put is a crippling nor'easter!  It would be our storm of the year if this model and everything leading up to this would actually verify!

The map above would drive sub-freezing air all the way to the Gulf Coast and into northern FL on the backside of a powerful sub 990 mb bomb just east of ACY and deepening!  The 500 mb anomalies are quite extreme as shown below.  The 500 mb heights are actually "off the charts"!

As I showed yesterday, the GFS reforecast hinted at this.  Here is the latest from that rather successful endeavor by the Earth Science Research Lab (ESRL), the Physical Sciences Division.

Here is the American GFS for the surface for the same time period next week.  Until both models tend to merge into more reasonable agreement, its quite uncertain that a major storm will disrupt the eastern half of the US.  As you can plainly see...nada.  Quiet and gentle NW flow of relatively mild temps.  But a few days later, a storm not quite of the Euro's immensity affects us here in the east.

But the GFS ensembles do show quite an anomalous trough over the east for the same time period.  So something is up.  Where's there smoke; there's fire!

So the jury is still out...time will tell...and all that jazz.  But it is the first time this winter where I feel that there is a real possibility of getting some appreciable snowfall here in the sub-tropics we call southern PA.  Unlike today, where there is a real likelihood of us achieving ~1 inch of rainfall by midnight.  Here is the latest NAM depicting SE PA as the "hot-spot" so to say in terms of rainfall amounts.

As the storm passes just to our NW over Lake Erie by midnight or so tonight.  Note the winds in their cyclonic movement just to the NW of PA.

Approaching another New Years Eve celebration in our lives and some things just never change.  So kick back and enjoy the piano version of "Old Long Ago" that is traditionally heard on numerous occasions at this time of year.  The lyrics, as simple as they may be, are provided as well.  Enjoy!

 

Should auld acquaintance be forgot,
And never brought to mind?
Should auld acquaintance be forgot,
And auld lang syne!

Chorus.-For auld lang syne, my dear,
For auld lang syne.
We'll take a cup o' kindness yet,
For auld lang syne.

Enjoy your mid-holiday-week!

Smitty

AA:  Watching a major storm possibility for next week.  Rainy today; breezy and much cooler tomorrow once storm pulls northeast of PA.

Rockin' Weatherwise Into The New Year

If you believe the Physical Science Division (PSD) reforcast model or the Euro, it appears that the 1st couple of weeks into January could get exciting around these parts if you're a lover of winter weather.  However, before I address those thoughts, lets look at what is coming at PA for the next 24-48 hrs.  Below is a current water vapor image of the US.  The blues are very wet regions of deep moisture in the mid and upper levels at the atmosphere.  Simply put, these pockets of atmosphere support moderate to heavy rainfall.  That blob is advecting directly towards PA.  Therefore expect a fairly healthy dose of liquid sunshine Tuesday into early Wednesday morning.

Here is what the NAM says in terms of amounts of rainfall for the period ending Wednesday midday.

Once the storm passes through by Wednesday at sunrise, cold and blustery conditions will prevail for Wednesday with daytime maxes struggling to get out of the 30s.  With winds gusting to 30+mph, it will feel like the coldest day of the week.  Take a look at the midday winds.

But what I want to really alert y'all to is the likelihood of some fun 'n' games beginning with the changing of the calendar.  The Euro has one deep trough digging deeply into the eastern US this weekend with a reinforcing shot of cold quickly following.  I am showing the deepest trough in the graphic below.  This is the operational run of the ECMWF forecast for Monday.

And here are the Euro ensembles for the midweek period next week...

And even the highly regarded PSD reforecast model that has been performing very well since its inception within the past several months!  That is most decidedly placing a deep trough here in the eastern part of the US with a ridge off the west coast.  This type of pattern should allow for some winter storminess here in the eastern part of the states and the northeast. 

Maybe January will have some winter wx to offer as being suggested by both the GFS reforecast project and the Euro Center's ensembles.  There are caveat, however, the primary one being no negative NAO or negative AO.  Thus any cold shot should be transient unless blocking upstream develops over the high latitudes near Greenland.  Trust me, there is plenty of cold Arctic air available in NW O Canada and AK.  Look at this article from Reuters...

Look at that cold over AK and NW O Canada.  Compare that to the anomalous warmth over the Mississippi Valley as shown by the GFS operational.  That will change somewhat as next week progresses with that digging trough that will usher in much colder air from the polar region.

OK...so we are watching for a pattern change...and that will not occur until the New Year.  Until then, enjoy Dan Fogelberg's version of Same Old Lang Syne from 1980.  This song has always been one of my favorite ballads about the adventures of life.  I hope you enjoy it as well...

Smitty

AA:  Looking to a pattern change to colder and stormier wx for the 1st couple of weeks in January.  A rainy Tuesday pm and a windy & cold Wednesday.

Merry Christmas!

I'm simply taking a brief break from what I personally consider to be the best 24-48 hour period of the calendar year in terms of pure euphoria and enjoyment whether you are a kid of 1 or 92...as the songwriter so eloquently sings.  But as everyone knows, the weather takes no breaks and the models were running as if this were just another day.  But the celebration of the birth of the holy child is far from any ordinary day...that is certain!  And the run of the 12Z ECMWF is far from ordinary as well.  As you can see, the model run below has a rainy scenario for us in the Tuesday time frame as the upper level low finally ejects from the desert SW and spins into quite a gale center affecting the interior Ohio Valley and New England!  Check out this prime locale if we had ANY arctic air in place for us here in southern PA!  Just a bit too far inland to allow for a major snow event in the lower SQ Valley.

But not for places further west...say west of the Appalachian Mtns and the mountains themselves as depicted by the GFS snow cover map.  The 2 maps below show the anticipated snow accumulations through midweek...thanks to the storm as shown above.  I believe any snow southeast of AOO to SCE to AVP will not accumulate.  Rain will be the operative word for us through Wednesday morning.

But then the true fun and games will begin!  The Euro sees a major amplification and buckling of the jet which has the potential to usher in the New Year with a major snowfall event as shown below.  Once again, it is waaaay too early to get excited, but the pattern is such that I can now buy into this numerical solution!  Well Golly gee...isn't that a beaut Gomer?  That's almost as glorious as the 1st Christmas morn....well not really; not even close!, but you get the picture!  Can you dig it?  If you like snow or own a snow blower that needs a serious workout, I know you're feeli' it!

OK...enough of the excitement.  That is a week away.  It's simply a mathematical interpretation of the atmosphere's whims over the next 169 hours...but it is sure inviting.  I will close with this this video that I thought was a great little ditty by someone who obviously has too much time on his hands and is a master at video editing!  I loved it and I hope you do too!  MERRY CHRISTMAS EVERYONE...and thanks so very much for humoring me by reading my weather opinions!

Enjoy your Christmas night!

Smitty

AA:  The Tuesday storm will be wet; the weekend storm should be WHITE!  Merry Christmas my friend!