Looming March Meteorological Monster?

Say it ain't so...oh no, Mr Smith!  Well, don't shoot the messenger, but the global modeling has been hinting at this for quite sometime and I simply wanted to bask in the record breaking warmth of this past week.  (Wednesday's 79°F was the all-time February max since official records began in 1888 at KMDT!) As so eloquently sung by Lindsey Buckingham and Christine McVie "...Yesterday's Gone..." and "...Don't you look back...", I must now begin to "think about tomorrow".  And as we all know, March can always have a few tricks up her sleeve and this year looks to be no exception.  Humor me for a brief post...

First the negative NAO blocking signal as shown by the Euro...this is a major block where shenanigans run rampant underneath.  That is a huge anomalous block over Greenland with a closed low strengthening over PA.  Now this is 7-8 days hence, but certainly does bear watching...

And the GFS shows a reasonable depiction of the surface chaos...

I always like to see what the analog package offers to get a sense of how the atmosphere might like to resolve itself with such anomalies using the CPC's super-ensemble analogs.  I perused the the top 2 hits and they are somewhat amazing!  Some of you will likely remember the Ash Wednesday storm of 1962!  It must have been a doozy as I remember reading an article published by the USGS on this storm a few years back stating it was up to that point, the most damaging coastal event to the eastern US ever!  That's saying something considering the major hurricanes that ravaged the east coast in the 30s and the 50s!

And this graphic remembering the Ash Wednesday storm looks similar to what both the GFS and the Euro seem to think might evolve...

And the 1958 analog though not the exact same week, a very similar pattern. A Cat 2 NESIS storm...

You see, Greenland blocks are very tricky, but they do tend to generate powerful and slow moving nor'easters.  With the upper air synoptics in place coupled with relatively warm water off the east coast and an increasing sun angle, the necessary energy requirements, the players are indeed on the field for a March meteo monster!  Here is an historical graphic depicting the surface low evolution of the 1962 storm that crushed the mid-Atlantic with heavy wet snows with the Shenandoah Valley being hardest hit.  I hesitate to post this...but I will.  Here is the somewhat consistent Euro for the past 3 runs now...this would be rather intriguing!

OK...off to watch the rain, low clouds, drizzle, fog, rising creeks...etc.  You get the point.  For my buddy Noah below...the Swatty should be well-behaved this weekend and start to recede by late Sunday evening...

I did have a couple of musical references, but this is the one I'll leave y'all with a slice of Americana...enjoy!  And enjoy your week's end!

Smitty

AA:  Rainy weekend; no $%!T Sherlock...right?  Watching the first week of March...winter just might make a rockin' return!

Healthy Hydrology

After last evening's snowfall on already saturated ground, prepare for the inescapable quagmire about to ensue today and later this week as this morning's glorious white landscape will evolve into one of muck, mud, and mire over the upcoming week.  As I mentioned yesterday, 2 days of likely max records coupled with more days with measurable precipitation than not will create our soggy landscape.  For those of you with creek and stream interests in our state, well, this hydrological post is for you.  I've always been fascinated with river and stream forecasting as the inputs to do so accurately seem far less than what is needed for numerical atmospheric and weather forecasting, but the myriad of variables is simply "ginormous"!  Let's start by diving into this, but I promise, we will only get ankle deep at best...

First, the current stream levels.  Many are at capacity as shown below.  Where historical data is less available, as opposed to assigning a specific percentile discharge, the term "High" is simply used.  One thing to note is that the majority of gages located along the main stem of the Susquehanna in PA are only in the 75-90 percentile; an indication that river flooding is quite common as most are aware at this time of year. However, blue dominates the graphic below; healthy hydrology!

The next graphic I will show is hard to believe seeing how wet it has seemingly been over the past several weeks; however, the extensive freeze of earlier this winter along with our very low water content snows of late December and January (along with a relatively benign autumn) put us into this "dry" condition as determined by the drought monitor.  This past week (left), we climbed out of drought from last week (right) into simply dry conditions.  I'm suspecting there will be no yellow this week in PA; not even any "yellow snow"!  And don't worry, I will not play Frank Zappa's "Don't You Eat That Yellow Snow" at the end of this...

Now a few specific streams.  First, the Susquehanna River at Harrisburg.  It should likely be completely ice free flowing past Harrisburg this week...but still muddy.

Now the stream I drive by each and every day (Yellow Breeches) but often can't see as sunrise is still near the relatively late 7 am hour...though we are on the underside of 7 am now here at our latitude!  Ye-haw!  Being spring fed, the Breeches has a healthy flow even in the dead of summer but like all others will respond to recent rains and snow melt as it did earlier this week.  The gage is located just behind Cedar Cliff High School...

For my loyal East Shore readers...and one in particular (Noah) who monitor and view the Swatty on a daily basis.  The gage for this creek is located about 1/2 way between the Manada Creek and the 39 bridge north of Hershey.

Simply reminiscing now, but I used to call...that's right...make a phone call to a recorded line to obtain the current levels for streams in the Susquehanna River basin.  The one of particular of interest to us for canoeing purposes was Penn's Creek.  You see, a necessary level was needed so as to not bang off rocks though the Poe region of the creek.  Penns is PA's longest limestone stream I believe and another with adequate water for fisherman most of the year; yet another reason to paddle this stream when the stream was up so as to not upset the many anglers.  The headwaters are actually Penns Cave, but arguably, the most scenic section runs from Coburn to Weikert, but by floating  further to Glen Iron made for a glorious day.  Currently, it is at a nice level to paddle...

Of concern is that over the remainder of the month, a plus anomaly is almost certain.  Clearly the graphic below indicates a plume of moisture laden air advecting from the gulf region towards the northeast US through the Ohio Valley and crossing PA.  Just exactly where the heaviest of the rain falls is still uncertain, but the modeling is indicating an unsettled time of it the next 10 days.  Dry weather will be at a premium to be sure...unless you're under the Bermuda High in the Atlantic!

Here is the current water vapor tracing across the CONUS...note the atmospheric stream from the tropical Pacific aimed at the northeast...

OK...enough.  But I would like to thank all of you who do read this and I truly appreciate your many observations, comments, questions, etc...As y'all know, I will always peruse the weather and its effects across not only PA but all of the country and even to some extent worldwide.  But I also like to from time to time share this with y'all and am happy that many of you enjoy it.  And I know some enjoy my musical selections as well; I hope you like this mellow one.  Listen to the lyrics in line one...thus my choice for today.  (I guess Paul didn't like winter?)

Happy Sunday!

Smitty

AA:  A wet time of it the next couple of weeks.  You'd swamp your mowers if you were mowing!