Smitty's attempt to educate and to a much lesser extent, entertain, about all facets of life; but primarily the meteorological and the climatological aspects of the earth sciences.
This upcoming week will once again feature spectacular late summer wx with a very brief surge of heat and humidity mid-week...let me quickly explain whilst I listen to my new and improved PSU Nittany Lions....do you hear it? Do you hear it? The infamous roar!
2 sprawling high pressure systems will move SE from central O Canada and keep most of the heat and humidity off to our south and west. There will be a brief surge Wed after high pressure system number one settles in for the Monday-Tuesday time frame...here are the forecast clear sky morning lows for Monday...temps will be a few degrees cooler since this is for 2 am and the is a few more hours of radiational cooling until the sun rises ~7:30 am...
It should be cooler than this am when I broke out my chamois shirt to help alleviate the chill. This map shows the surface pressures and the humidity, or in this case, the lack thereof, at the same time Mon am...PWATS are known in the biz as "Precipitable Water". The larger the number, the more humid the air mass...
This 1023 mb will exit stage right and allow for the heat and humidity over the lower Miss Valley to advect NE towards PA. By Wed pm, temps will surge to near 90F and the absolute humidity will easily double making Wednesday possibly the last truly hot day of 2013!
Note the surge of the "green" or higher PWAT air moving towards PA! From an even purer scientific point of view, look at how the center of lower pressure literally is pulling this less dense air towards its center located in Quebec, north of my favorite eastern state, MAINE!
However, lurking off to the NW is yet another surge of cool, dry O Canadian air being ushered in by high pressure so by Saturday am...here are the forecast low temps...note how the lakes are much warmer than the surrounding land adjacent to it. Makes for good grape growing and wine making on the SE shores of Erie and Ontario...or so I am told!
Accompanying that air mass is the much drier air as we see in this model of both PWATs and surface pressures...a nice "banana" high that in the winter would love to be attacked from the SW and lead to a nice overrunning event of snow and ice...not too long for the fun and games to start!
By the way, with this absolutely perfecto wx, all of nature's creatures are taking advantage. Look at what Kay spotted outside our humble abode...simply awe inspiring and impressive!
And a wider view to note the engineering intricacies of his (or her) web; not sure of the structural importance of the "zig-zag" pattern above and below his (or her) body? But it is pretty wild!
Ok...with all of that said, enjoy the remainder of the weekend...and enjoy Boris!
Keeping an eye on the tropics....
Smitty
AA: Nice weather continues next week but with a brief surge of heat and humidity for Wednesday.
Here were are as we enjoy absolutely spectacular September weather, the question was once again asked of me "Smitty, where are all the hurricanes?" Obviously, my circle of friends are well educated knowing that as we enter deeper into the month of September, hurricanes in the Atlantic basin are usually commonplace. In fact, here are some climatological statistics for tropical storms and hurricanes for the Atlantic basin using the 30 year period from 1981-2010:
Named Storms per year: 12.1
Becoming Hurricanes: 6.4
Becoming CAT 3 or greater: 2.7
Here is the current wide angle view of the Atlantic via IR satellite imagery:
There are 2 areas of disturbed wx, the broad circulation just to the NW of the Yucatan Peninsula and the double barreled low over the Leeward Islands. In fact, if the atmospheric energy could work in cahoots as opposed to stealing each other's thunder, a named system would likely develop just to the north of PR. As of this writing, that does NOT look likely.
So what is this title about...ACE? A relatively recent manner in determining how active a tropical season was or was not is not by simply looking at how many storms formed, but to apply a quantitative measure based on wind energy created by these tropical cyclones. The acronym ACE represents "Accumulated Cyclone Energy". For those of you who are truly interested or are like me and really don't have a life outside of weather and some good music, the ACE index is derived by summing the squares of the max sustained wind speed (knots) measured every 6 hours for each and every named storm while they are at AT LEAST tropical storm strength. Here is the ACE Index as viewed climatologically for both hemispheres...clearly September is the high ACE month in the NH!
So where do we stand today? In the Atlantic basin, we are obviously WELL BELOW NORMAL! Our normal ACE Index at this point is 39...we are presently sitting at 8.3! All of August and nearly 15% of September are gone! The Atlantic better start kickin' to get even close to normal...here is the ACE as compared to the last 11 years...2013 is the black line running across the bottom. The vertical blue line is today.
By the way, here are the numbers of tornadoes reported YTD...again, 2013 is the black line that is well below the other lines indicating a severe season with many fewer tornadoes as compared to recent years gone by.
And the prospects of a flourish of hurricanes is not really in the cards of many of the global models. Here is the Euro showing some signs of life 7 days hence...
With all of that said, I'll leave you with a different kind of ACE...enjoy!
And enjoy the end of your work week...
Smitty
AA: It's been a below normal season for tropical storms to date when using the ACE index. But ask any of the land barons along the east and Gulf coasts; they are all quite fine with this lack of activity!
As we now proceed deeper into the month of what is often some spectacular wx for the year, it is always good to look back at what we just endured...and that is August 2013. And remarkably, August had NO DAYS...NONE, where the max temp reached 90F! In fact, on only 3 occasions did the mercury top out at 87F; the 27th, 30th, and 31st. The lowest temp for the month was 53F on the 15th of the month. Here is a climatogram of temps for KMDT.
I believe it is plainly evident that the bulk of the temp bars spent most of their time at or below normals with the notable exception of the past week. In fact, while perusing the entire year, again, with the 2 exception2 of late Jan and early April, cool was the rule for most of 2013 in KMDT to this point.
As for precip, KMDT is running a few inches below the 30 year average to date. Here is a quick graphic showing the accumulated precip for the calendar year to this point. It seems strange that we are running a deficit of rainfall, but the numbers don't lie! KMDT had 14 days of measurable rainfall in August, but only 2 of the days had in excess of 0.50" of rain, the heaviest falling on the 28th where the airport received 0.92". It's just that the torrid heat that often persists for spells over our summers just wasn't present this past August.
There was a very unique precipitation event not too far to our east however at the end of July in the City of Brotherly Love. Look at the 8.02" at the end of July and the spike of accumulated precip that will not allow Philly to run a precip deficit this year! A narrow band of intense thunderstorms trained right over the airport and voila, and incredible event is now forever recorded in the books at KPHL! Two and a half month's worth of rainfall in about 2 hours! Unreal!
So while Philly is running a huge surplus, we are running a 3" annual shortfall in precip! Clearly, though, the temps were more in line with KMDT as Philly also had a cool August. In fact, both KPHL and KMDT ran ~1.5F below the 30 year average for the month of August. Had it not been for the anomalous heat the last week of August, a much larger deficit would've been achieved for August. I'm not sure why I don't see the GW crowd touting that fact?!?
So what does September hold in store? The CFS v2 suggests a warm west especially up into O Canada, and cooler east, again especially up in the province of Quebec. In these parts, we should see a progressive pattern meaning swings in temps from below norms at times to above norms. Statistically, it should all balance out to very much near the 30 year average by month's end...
And speaking of August, I'll leave you with what I believe might be the most famous cut off of Eric Clapton's 10th studio album released in 1986 titled August. He and Phil Collins collaborated to produce this number one hit that many will recognize as being in the Tom Cruise-Paul Newman film, The Color of Money. Enjoy this "August Flashback"...and enjoy your mid-week spell of spectacular wx!
Smitty
AA: August was cooler than normal and believe it or not slightly drier than normal! And August was a good LP released in the mid 80s by one of my favs, EC!
A bona fide cold front will pass through within 24 hrs of this posting...and from this seat, a welcomed change to the current month in which we now reside. Here is the 850 mb temps as forecasted by the Euro for tomorrow am...
And a secondary shot of autumn to be felt in these parts later in the week...say about Friday...
But later in the medium range, the heat from the southern plains is threatening to return...here, the Euro shows a broad SW flow advecting heat and humidity towards PA. In addition, if there are any tropical troubles, and there very well may be, this pattern allows for a tropical system to move along the Appalachians up towards these parts beginning any time from this weekend on...
Here is the NAM tropical wind swath suggesting the potential for a storm to be moving towards FL by late in the weekend...I don't really but this solution, however...
O Canada keeps this potential well off to the N and E of the CONUS...albeit, a formidable storm nonetheless...
So on this Labor Day, 2013, the final day of summer as viewed from an historic point of view, we enjoyed late season heat and humidity. However, as we progress deeper into September, most notably this week, cooler and much drier wx will become the served up on the wx menu. With that said, let me leave you with one of my favs off an album released in 1970 with an appropriate title for today...
...and here is that tune...from a live version album (Europe '72).
Enjoy your Tuesday and the beginning of your WORK WEEK...for most of you reading this...
Smitty
AA: Cooler and drier this week. Warmer air returns next week. Still watching the tropics and listening to good tunes.
