High Pressure but it’s OVC - why?

RyanB

RyanB

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Here’s the current synoptic picture. I’m in SE Tennessee and as you can see, there’s high pressure right over us, yet it’s solid overcast all across the region with a ~2000ft ceiling. What gives?

F7A1430B-E31C-4146-8C77-476C5B5810F2.jpeg
 
Where does it say that a high pressure can’t be overcast?

looks to me like the high is bringing moisture from the east and the low is bringing moisture from the south into the area.
 
Exactly as MS noted. High pressures tend to be good VFR weather, but if there is enough moisture pulled in, you’ll get clouds. Happened to me around NYE last year when I was stuck staring at ice bomb clouds for 3 days straight and it was a high pressure the whole time.
 
masloki said:
Exactly as MS noted. High pressures tend to be good VFR weather, but if there is enough moisture pulled in, you’ll get clouds. Happened to me around NYE last year when I was stuck staring at ice bomb clouds for 3 days straight and it was a high pressure the whole time.
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Makes sense. Must be moisture getting pulled in from that stationary front around the gulf coast.
 
RyanB said:
Here’s the current synoptic picture. I’m in SE Tennessee and as you can see, there’s high pressure right over us, yet it’s solid overcast all across the region with a ~2000ft ceiling. What gives?

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Click to expand...

High is relative. Looking at the altimeter settings, they are around 30.00 even, so not really that high.
 
RyanB said:
Here’s the current synoptic picture. I’m in SE Tennessee and as you can see, there’s high pressure right over us, yet it’s solid overcast all across the region with a ~2000ft ceiling. What gives?

View attachment 108567
Click to expand...

the southeastern US is famous for our persistent summer highs (usually the Bermuda high), and local inversions due to the “hill & dale topography that traps both moisture & pollutants (like TVA smoke) near the ground. Sunlight striking the pollution creates ground level ozone over time, which means the visibility goes down with time. Come September, we’re actually glad to see those heat-engines (hurricanes) redistribute the heat, wring the moisture out of the atmosphere, & settle the pollutants. Summer sailing & flying in the SE are hot, sticky, & low vis.
 
You are in an area of "zonal flow" now, which can carry disturbances from east to west causing crappy weather even without a low. This includes some nasty convective activity.

That analysis is worth what you paid for it, lol.
 
OVC002 at KPUJ in NW Atlanta. Popped into the clouds at 005 and only saw the ground at MDA / DA. IMC the entire flight. Great day for IMC currency.
 

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RyanB said:
Here’s the current synoptic picture. I’m in SE Tennessee and as you can see, there’s high pressure right over us, yet it’s solid overcast all across the region with a ~2000ft ceiling. What gives?

View attachment 108567
Click to expand...
I came out of my PPL also thinking the high pressure days will be the best days with no exceptions. Learned the following summer that weird stuff really happens during some of the high pressure areas. To me the weirdest one is that its literally CAVU for 100 miles in any direction. But then right at our destination clouds form and it starts raining. And I just had a more signficatn thing happen up here in MN/SD on Saturday. The wind was even up to about 7kts, enough to make the wind turbines turn. And well after noon, temps in the mid 80's, winds about 7kts we had ceilings as low as 800ft with few at 300ft. I did some over the top and thankfully our home base was wide open. But our destination wasn't so we had to divert. Maybe its worst where you are but this was 100miles wide for an entire day. It was a case where humidity had dropped the night before, wind slowly switched to SE and must have been just the right amount if moisture pumping in to main OVC all day but not rain. Here's a shot where it just opened up for about 15 miles. All the rest was solid OVC. Its hard to tell in the picture but several of them are in the low clouds and turning.

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Go here and click on the map for your area. https://aviationweather.gov/fcstdisc Depending on who does the weather in your region, it can be a pretty good discussion of what's happening and sometimes why.
You do have to make sure to scroll down below the map image to see the discussion.
 
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