Weird Windshear

I thought this was interesting so I'll share it. I hit some unusual
windshear I suppose last night going into St. Simmon's Island, GA
(BQK) in an A36 Bonanza. Here we were, me flying and the non-pilot
owner (my brother-in-law) in the right seat cruising at 3000 over the
top of a broken layer about 25 south of the localizer to runway 7,
about 9:30 EST. We were in moderate to occasionally severe turbulance
and I had been warned by the FSS briefer about a windshear at 1000 agl
- I think it was the fact that there was a 180 degree diff in wind
direction between the surface and 1000 agl that was causing it. Oh
yeah, a big fat low pressure was sitting right on top of BQK, more or
less, as I could determine from the duats graphical current analysis in
the motel room an hour later. The pressure had been dropping since
Atlanta and the altimeter was down to 29.68 I believe. Anyway, here we
are in flat out cruise, I look up and notice I'm only indicating 140
or so when I should see 165, and dropping a couple of knots per second.
As the airspeed goes through 110, I bring in full RPM and manifold and
we continue to lose airspeed down to 80 knots. I'm wondering what the
heck is going on, we're now in a climb attitude and get one blip of
the stall warning. By this time I've disengaged the ap and now am
allowing the airplane to drop to maintain around 80. I'm just about
to call ATC when we start picking up airspeed, slowly. Man, that was
weird.

Were there any mountains or hills around? It could have been a mountain
wave. I had experienced the same exact thing in upstate NY/Massachusettes
border heading northbound with a wind coming from the northwest. Did you
start picking up speed afterward? After I had experienced the downdraft
where I had full power in to maintain 80kts and my altitude, I then needed
to keep a descending profile to again maintain the altitude with a
corresponding 135kt IAS.

Everyone I talked to that had experienced this said it was very weird the
first time they encountered it.

Marco Leon

"Bravo8500" wrote in message
oups.com...
I thought this was interesting so I'll share it. I hit some unusual
windshear I suppose last night going into St. Simmon's Island, GA
(BQK) in an A36 Bonanza. Here we were, me flying and the non-pilot
owner (my brother-in-law) in the right seat cruising at 3000 over the
top of a broken layer about 25 south of the localizer to runway 7,
about 9:30 EST. We were in moderate to occasionally severe turbulance
and I had been warned by the FSS briefer about a windshear at 1000 agl
- I think it was the fact that there was a 180 degree diff in wind
direction between the surface and 1000 agl that was causing it. Oh
yeah, a big fat low pressure was sitting right on top of BQK, more or
less, as I could determine from the duats graphical current analysis in
the motel room an hour later. The pressure had been dropping since
Atlanta and the altimeter was down to 29.68 I believe. Anyway, here we
are in flat out cruise, I look up and notice I'm only indicating 140
or so when I should see 165, and dropping a couple of knots per second.
As the airspeed goes through 110, I bring in full RPM and manifold and
we continue to lose airspeed down to 80 knots. I'm wondering what the
heck is going on, we're now in a climb attitude and get one blip of
the stall warning. By this time I've disengaged the ap and now am
allowing the airplane to drop to maintain around 80. I'm just about
to call ATC when we start picking up airspeed, slowly. Man, that was
weird.




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Oops, I said 25 south, I ment 25 north. It was flat as a cracker. I
didn't have the increase like you were saying ... I've felt smaller
up/down drafts going in and out of cumulous before, but this occurred
over a lenghty perdiod of time relatively, like 30 seconds or so. We
had had a strong head wind all the way down, but when we were doing 80
indicated, I now remember seeing 97 on the GPS. I was on the localizer
a few minutes later and so I didn't get a chance to see how strong the
tail wind was. After we landed, driving to the motel, we noticed the
smoke from a paper mill descending after it left the stack. I wondered
if that was somehow related ... descending air? Low pressure, hmm.

"Bravo8500" wrote in message
oups.com...
After we landed, driving to the motel, we noticed the
smoke from a paper mill descending after it left the stack. I wondered
if that was somehow related ... descending air? Low pressure, hmm.

Oh man the dreaded stinking papermill! I do mean stink too! There's one in
Jesup , GA that will just turn your stomach within 30 miles of it! The one
there in Brunswick never bothered me much, I guess I got lucky and coastal
winds blew the funk the other way! Brings back memories,..ah to be home
on the banks of the Ogeechee in good old Georgia.

Patrick

"W P Dixon" wrote

Oh man the dreaded stinking papermill! I do mean stink too! There's one in
Jesup , GA that will just turn your stomach within 30 miles of it!

The locals say that that is the "smell of money." It is fermentation,
breaking down the pulp.

This windshear was all related to the passage of the developing storm, a
Nor'easter, now headed up the east coast. Lots of complex things going on.
A cold front was in the area, so you have warm air from the south rising
over it, air from the north blowing and being trapped under the rising warm
air, and changing directions along the frontal boundary. Now add to that a
developing low pressure system, and a good bit of convection activity, and
you have a ......well, a mess! ;-o

That there is some 'o those tecqicquanal wather terminiiligy!

I'm about half surprised there was not some of that solid h2o mixed in there
somewhere, too.
--
Jim in NC

Lots of complex things going on.

I think you're exactly right. That sounds right on with the warm air
from the south and the cold from the north underneathe. I thought it
was interesting how the briefer got it right on too with his warning. I
heard one controller tell someone up high that there was strange
jetstream pattern or something. They were all getting beat up. There
was a tornado reported a couple of hours before we arrived. The forty
mile an hour winds and rain had moved offshore about that time, a
couple of hours before. This gives me new respect for
windshear/downdrafts. My bro-in-law told me he has heard of trees being
flattened by downdrafts. If they can flatten a tree, they can take an
airplane and plant it, no doubt. I went down the ILS into Huntsville
one night when they were giving Low Level windshear alerts .. next time
that happens I'll have them vector me around some before attempting it,
having experienced it.

"Marco Leon" mleon(at)optonline.net wrote in message
...
Were there any mountains or hills around? It could have been a mountain
wave.

I don't think he had problems with mountains or hills at St Simons
Island,...it's a island off the coast of Georgia. A tool bridge away from
Brunswick , GA . Really flat land. Maybe winds coming ashore?

Patrick

W P Dixon wrote:

"Marco Leon" mleon(at)optonline.net wrote in message
...

Were there any mountains or hills around? It could have been a
mountain wave.


I don't think he had problems with mountains or hills at St Simons
Island,...it's a island off the coast of Georgia. A tool bridge away
from Brunswick , GA . Really flat land. Maybe winds coming ashore?

Here in NC you can get mountain waves a few hundred miles downwind from the
Appalachians, though I've never experienced anything as severe as the OP
describes. I think St Simons is too far south for Appalachian mountain waves,
though.

I cannot personally speak for the "a few hundred miles", but I have
experienced mountain wave within ten nm of the lee side of the
Appalachians in both North Carolina and Georgia.

Dave Butler wrote:
Here in NC you can get mountain waves a few hundred miles downwind from
the Appalachians, though I've never experienced anything as severe as
the OP describes. I think St Simons is too far south for Appalachian
mountain waves, though.

On Fri, 04 Mar 2005 22:16:49 GMT, jsmith wrote:

I cannot personally speak for the "a few hundred miles", but I have
experienced mountain wave within ten nm of the lee side of the
Appalachians in both North Carolina and Georgia.

Dave Butler wrote:
Here in NC you can get mountain waves a few hundred miles downwind from
the Appalachians, though I've never experienced anything as severe as
the OP describes. I think St Simons is too far south for Appalachian
mountain waves, though.

Some where around here I have some photos of lenticular clouds over
the Michigan, Ohio border taken from the company King Air.

The Pilot and copilot were remarking that was something you just don't
see around here, but there they were.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com