Hammered by the Closed Low Aloft

Most of us remember from ground school that air circulates clockwise around a high and counter clockwise around a low pressure center. It’s useful, I guess, to know this to help understand what is happening overall with the weather. But most of the time I just look at the streamlines on the winds aloft forecast map, note that the arrows are blowing directly from my destination to the departure airport, and groan about the yellow or orange color that indicates the headwind is really strong.

The counter clockwise circulation around low pressure gets lots of attention every hurricane season when satellite and radar images show the wind racing around an intense low pressure center. I don’t pretend to understand all of the ingredients necessary to cause a tropical storm to form, but we all hear repeatedly that it is the heat of warm ocean water that fuels the storm. And the low pressure of a cyclone is at the surface so a falling barometer is a very positive indication that nasty weather is on the way.

But there is another low pressure system that is not all that common but makes the flying weather over a huge chunk of the country just plain miserable for days and that is the closed low aloft.

Actually, closed low aloft is now a little used meteorological term. The more common name for these nasty phenomenon is now cutoff low. By either name this is a low pressure system that forms in the upper atmosphere and the circulation is closed, meaning the wind makes a complete counter clockwise circle as it does in a tropical storm or hurricane.

For a closed low to form it must be cut off from the jet stream. Forecasting the formation of a cutoff low is notoriously difficult. Because the low is not being propelled by the jet stream it is almost impossible to predict reliably if it will move, where it will move, or when it will move. And forecasters don’t have much success in predicting when the cutoff low will break apart.

A cutoff low can bring days of strong winds at the surface and aloft, and drenching rains over the same spot. Convective activity pops up all over the place under the low, and the strong winds that shear with altitude and small changes in distance creates huge areas of moderate or greater turbulence. Flying into a cutoff low is simply something none of us wants to do.

As luck would have it a cutoff low formed over the southern states a couple days before I planned to fly from home base in western Michigan to Savannah. The low brought severe storms to eastern Texas, Louisiana, Arkansas and Alabama, and serious flooding in Georgia. I hoped the low would break up or move away before my trip. It didn’t.

The northern edge of the low pressure circulation was very clear on the weather radar mosaic. I could fly along the northern edge almost to the east coast and then make a right turn for Savannah and miss most of the worst weather. But the southeast wind aloft was blowing 50 and more knots. A trip that normally takes 3+45 would take 5+30 so a fuel stop was required. I picked Greensboro as the most southeasterly spot before the weather became really terrible.

By the time I slogged into GSO it was raining, the surface temperature was barely 50 degrees, and it was howling out of the east. Then I had to turn back to a southwesterly course for Savannah and fly through several bands of rain, continuous turbulence, and 50 knots of headwind component even though I stayed at 4,000 feet.

About 30 miles north of Savannah I flew out of the clouds into clear air, the temperature jumped up 10 degrees C, it was in the mid 70s on the ground and the wind was less than 5 knots. The people at the FBO told me “you should have seen how bad it was here this morning.” I think I did see that just a few miles north.

That’s the way it is with a cutoff low. Terrible inside, but not far away the weather is fine. Of course, I got to fly back home the next day and the low was still there but had moved just enough that yesterday’s headwind became mostly a crosswind so I had little help. A closed low aloft is surely Mother Nature’s punishment for pilot’s past sins.

This entry was posted in Mac Clellan's Left Seat Blog. Bookmark the permalink.

29 Responses to Hammered by the Closed Low Aloft

  1. To me, the most important thing about your story is that you made it to your planned destination more or less on schedule, rather than throwing in the towel. That’s what serious pilots — by which I mean pilots who use their GA airplanes for serious gotta-be-there-on-time transportation — do. We may have to duck and weave and try Plan B and then Plan C, but we find a way to get there.

    I must confess that today’s satellite-downlinked nearly-real-time weather in the cockpit makes this a whole lot less exciting than it used to be in the bad old days.

  2. Cary Alburn says:

    Go, my son, and sin no more. :)


  3. Bill says:

    Why would anyone want such misery?

  4. jay says:

    Don’t know for sure but would bet Delta flys there at less cost and more comfort (in the air).

  5. Mac says:

    Well, I hope you guys are not pilots. Of course, you can even drive under a closed low without a hint of turbulence. But it starts out as work when you tell somebody you will be there at such and such a time. And then it becomes a challenge to make the trip on time with acceptable risk.
    Do you think pulling a bunch of Gs is fun and comfortable? Or pushing over in outside maneuvers that stretch everything the wrong way is cheap and fun? That’s what aerobatic pilots or military pilots do for their own reasons.
    Or how about wrestling a taildragger to the ramp in a strong wind when the guys flying nose gear airplanes just drive in? Is that work or fun?
    I know the answer. It’s a challenge. We all fly for our own reasons and my reason is to go where I want when I want on as predictable a schedule as possible. And a closed low aloft puts the interest into what some pilots think is boring point-to-point flying.
    To each his own, but I yield nothing to Delta or any other airline. Besides, if an airline was on schedule the trip would still have taken three hours longer door to door than my slow trip around the closed low.
    Mac Mc
    Mac Mc

  6. Matt says:

    Geez Mac, must have been a pretty special occasion.

    I’d guess you spent somewhere near $2,000 in gas alone getting there and back, all for one night in Savannah.

    Of course I get the whole “getting there on time, on my own schedule” thing, but at what price?

    Not trying to condemn you here, just curious to hear how you rationalise such expenditure.

    • Ronald Pogatchnik says:

      Wow Matt, sounds as if you do not understand what Mac said. We fly because we love it, we can, and it is fun. We don’t fly when we can’t afford it .

      Why so negative.

  7. SkyGuy says:

    Guess Mac has the $$$$.

    We don’t.

  8. Josh says:

    The last couple years I’ve given a lot of thought to this idea of rationalizing the cost of flying – the conclusion I’ve come to is that you don’t. At least if you’re flying for fun. Not anymore than you should try to rationalize a Harley or a boat, a new house or even a new cell phone.

    My family and I recently flew our old Cessna 172 from Ohio to Florida. The trip was an absolute ball – we had just enough different weather to make the trip interesting. Not only were the challenges of the flight personally gratifying to me, I was kind of a celebrity to friends and family who could only dream of doing something like that.

    I will say this – a person does need to look carefully at what aircraft they fly and the costs involved. Being in the business, I generally advise new pilots to buy an aircraft that is well below what they can afford – we all know the guy who bought the high performance retract or twin that is a hangar queen because they can’t afford to put gas in it or maintain it. Better in my book to be the guy that has a Cessna 150 and flies it an hour or so a week.

  9. jay says:

    Mac, I’m a pilot and own a tailwheel plane. Thanks for asking Would just rather yield to the professionals if I absolutely have to be there. I call it aeronautical decision making and financial common sense. But hey, that’s just me.

  10. Thomas Boyle says:

    Ladies and gentlemen,

    We share a common love of flying.

    I suggest that any of us who feels inclined to criticize the flight activities and motivations of other fliers, needs to get out into the world more.

    Most people don’t fly at all.

  11. Bill Strawn says:

    Why I Fly My 182 versus Southwest (who I love dearly):
    1. Security is opening the hanger door, not being lovingly stroked by an unattractive TSA agent.
    2. I have met the greatest people at small airports and FBOs, who are not pushing past me to get to their gate to wait for an aluminum tube.
    3. My bride makes the best PB&J sandwiches for when we are flying, and they beat plain peanuts.
    4. Cause I saved my meager salary as a working stiff, and now have a little of those savings to spend on something few others in this country know about, much less do.
    5. Nothing beats a beautiful blue sky above a cottony, rolling mass of clouds, while I listen to the pros wish they could change their destination in a storm as easily as I do mine.
    6. I have wanted to fly since I was a young child, and finally can.
    7. I figure what I spent on each years tuition for 7 years of kid’s college can now go to enjoying my airplane.

  12. KB says:

    Thanks for the article Mac, I’d heard of a cut-off low before in weather briefings, but never bothered to find out more. We at Houston Center dealt personally with this system for days. It’s no fun for the controllers on the ground either. Having deviations around weather is one issue, but the added workload and frequency congestion of requests for ride reports, altitude changes, etc. is miserable…well…mainly because everyone IS miserable.

    And to those who advocate flying commercial instead, you might be safer and less stressed (arguably), but the bumps will be as bad or even worse at 460 knots vs. 170 knots. It will be uncomfortable either way.

  13. Gary B. says:

    I learned long ago (relatively speaking) that there are some things worth more than money. I’m not “rich” by the definition most people think of, but I don’t claim to be poor either; certainly not if I can afford to own my own plane (even if it is only a 1/4 share in a modest Piper Archer II). Using this aircraft (or my flying club’s aircraft, if I can’t use my own for whatever reason), I frequently fly to visit family in MD, which is about a 2-2.5hr flight from my home base in CT. Taking the bus there would be the absolute cheapest way to travel, followed by car, but I loath the thought of a 4-6hr highway journey. The train really isn’t any faster, nor is commercial aviation, which leaves general aviation as the preferred mode of transportation when it comes to time between points. My weekend trips would not at all be the same if it wasn’t for GA.

    However, it does mean that occasionally (often?) I have to deal with en-route weather that doesn’t want to cooperate with my plans. Certainly, my plane is far less capable than Mac’s and I am thus forced to cancel more often, but it does still mean having to work my way through some less-than-ideal weather. Knowing a little bit about how the weather works, and having data-linked weather in the cockpit, can go a long way towards managing the risks properly.

    I would like to see more blog entries about how to properly manage these risks, and how the loss of certain equipment (XM WX failure, for example) impacts the decision-making process. There are right ways and wrong ways to “push the boundaries” (after all, we never would have made it past the first flight lesson if we weren’t continually pushing the boundaries in a methodical, safety-oriented nature), and it’s something all VFR and IFR pilots should learn, regardless of what equipment you fly.

  14. Ed Roo says:

    I think back to the previous century when Duane Cole was flying from airshow to airshow in his clipped wing TaylorCraft. He never missed an event because of weather.

  15. Marc Taylor says:

    I found Mac’s article very informative. I don’t follow the math on $2,000 in fuel. And I certainly don’t enjoy traveling on any airline these days.

  16. Richard Montague says:

    As near as I can tell the concensus here is that Mac should have made the trip on a Harley.

  17. Shannon says:

    This article presents clear idea for the new people of blogging, that truly how to do running a blog.

  18. Spot your order now as stock is very restricted.
    Feast your eyes & thank you for your patronage:) Have a barokah day ahead.

  19. Donnie says:

    Far more detailed details can be accessed at the BC Student Outcomes
    internet site.

  20. Shana says:

    Super affordable price tag for super amazing service!

  21. Both are excellent and do the job.

  22. Janell says:

    Dr. Snow traced the cholera outbreak to the Broad Street pump.

  23. Mari says:

    By the tip of 2012, this quantity had dropped to $three,543.00.
    Nevertheless, there are a number of contributing elements that will have an effect on the overall value
    of breast augmentation surgery.

  24. Annmarie says:

    Headgear delivers measured quantities of pressure in particular instructions to achieve optimal results.
    Headgear works only when it is worn by the patient as prescribed by the orthodontist.

  25. Kelli says:

    Cover up, regardless of the temp(at worst carry sarong and over shirt
    with sleeves) or be refused entry, even at the Sistine Chapel in Rome
    or you’ve gotten wasted your time standing ,waiting and sweating.

  26. Erica says:

    The second class (Protections) will not be as apparent.

    Car rental companies offer several insurance choices. You
    absolutely have to consider insurance coverage earlier than you arrive at the counter.

Leave a Reply

Your email address will not be published. Required fields are marked *


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>