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An 86 deg. F dew point!!

Dan Chaffee

An hour ago, Orange City, Ia recorded an 86 deg. dew point. I don't remember ever seeing this anywhere in conus. That's higher than
typical Bangkok, Thai values! Unbelieveably enough, there are locations
that commonly experience 90+ deg. F dew points; Yeman for example.
 
Having an 86F dewpoint must be like being in the tropics! Here in Iowa the highest dewpoint I have seen was 83F a few years ago. A heat advisory has been issued for my area tomorrow where temps will be in the 90s with dewpoints running in the 70s to near 80F!! :shock:
 
Dang someone beat me to it. I was out earlier today and it was just too damn hot and nasty. The terrain over there in the hills seems to allow the dews to pool higher than normally around all the corn. I've been watching those 80 TD readings over there much of the day. I missed the 86, but in Onawa IA right now it is reading 99/85. "Fun" stuff. It doesn't hardly seem fair that this area honestly sees the highest TD and temps(combo) each summer in the US and during the winter gets to be too damn cold too.

Oh yeah and spc meso page indicating sbcabe of 8000 in sw IA.
 
One should be careful when getting too excited about many of the Iowa AWOS/ASOS station's dewpoints thanks to their close proximity to corn fields. During warm spells like this the microscale evapotranspiration from the corn can see pretty extreme dew point spikes...I have no doubts that the ambient Td is around 80F but that 86F value is probably aided by some dense corn nearby.
 
Originally posted by Nic Wilson
One should be careful when getting too excited about many of the Iowa AWOS/ASOS station's dewpoints thanks to their close proximity to corn fields. During warm spells like this the microscale evapotranspiration from the corn can see pretty extreme dew point spikes...I have no doubts that the ambient Td is around 80F but that 86F value is probably aided by some dense corn nearby.

Sure , but to someone who must to work in, or for animals that are subjected to those conditions, it makes no difference what is responsible for the spikes.
 
Yeah alot of western IA has been reading above 80 for TDs today. NE has alot of corn but the readings aren't as bad. I think more than anything it is the terrain there AND the moisture convergence(pooling) going on in that area right now. Onawa is now 101/87.
 
Originally posted by Nic Wilson
One should be careful when getting too excited about many of the Iowa AWOS/ASOS station's dewpoints thanks to their close proximity to corn fields. During warm spells like this the microscale evapotranspiration from the corn can see pretty extreme dew point spikes...I have no doubts that the ambient Td is around 80F but that 86F value is probably aided by some dense corn nearby.

Doesn't matter if it's in close proximity to a cornfield or not - an 86 dewpoint is murder. I think the emphasis in this case is more on the human effect and not the meteorological cause/effect.

I am outside all day, most days, and I could tell a difference in today's conditions as opposed to the past few weeks. I don't know what the HI was today but I'd bet it was at least 100. I can only imagine our heat (Norman) with an 86 dewpoint. That's simply suffucation on land.
 
There was apparently a 90F dewpoint recorded yesterday at 2005z at KENL (near Mt. Vernon, IL) if the decoder at work is accurate. A couple hours of 88F dews to boot. 97 over 90 is just plain nuts. The highest dew I've ever heard of was 94 on the Red Sea coast of Saudi Arabia with a heat index of 154F. U Wyoming has surface data for the Middle East. I noted some 110/75 obs there. Yuck!
 
Its amazing how it can get this hot yet be below zero 6 months from now....temps were in the upper 90s-low 100s with dewpoints in the mid 70s. I guess that is one of the perils of living in the midwest. The early settlers must have had a rough time without the luxury of convienent heat and a/c :? (not to mention the violent weather not seen by many early settlers)
 
I've never heard of a 90F dewpoint temp in the US before, looks like it may be a LOOOOOOOOOOONG, summer... :shock: :cry: :lol:
 
Originally posted by Craig Maire II
I've never heard of a 90F dewpoint temp in the US before, looks like it may be a LOOOOOOOOOOONG, summer... :shock: :cry: :lol:

I don't know how long it will be, but it certainly appears that it will be a humid one. Those are really high dew points.
 
Originally posted by Craig Maire II
I've never heard of a 90F dewpoint temp in the US before, looks like it may be a LOOOOOOOOOOONG, summer... :shock: :cry: :lol:

During the July heat wave in 1995 Appleton, WI reported a 90 degree DP. If memory serves I believe their observation was 103/90 HX 140 something.
 
Dewpoints are over 80 all over the midwest again today. Highest one I can find now is 84 at Shenendoah IA. Even here, sitting in an officially extreme drought, we have dewpoints in the mid 70's.
 
Here's that obs Justin mentioned.

Code:
KENL 212005Z AUTO 21005KT 10SM CLR 36/32 A3003 RMK AO2=

97 deg F temperature, 90 deg F dewpoint. Sounds too insane to be true.

Hey, at least there was a 5 knot breeze!

Tim
 
Map at the time of that obs... you can see the 90F dewpoint a tiny bit south of the image center.

05072120.gif
 
From the map, it looks like the 90 is out to lunch, surrounded by mid 70s to low 80s. Also, the 88 up in east central IL is highly questionable given the surrounding observations.
 
Looks like a typical day in New Orleans in July and August. It always feels like your walking around in a big oven wearing a wet quilt. I will take the temps in the 100's before the td's in the 80's anyday. I remember when I was working in Brownsville a few years ago and I got on the plane at valley airport and it was 106 and when I got off in New Orleans it was 96 but the humidity just takes the air out of your lungs, it is miserable.
 
I would say I'm happy to be in Tokyo right now rather than baking back home in Nebraska, but it's oppressive here as well. The heat isn't too bad, but the humidity is ridiculous at times - especially close to the Bay, which is where I live/work.

Once Typhoon Banyan passes through tomorrow, however, the weather should improve temporarily. I'm looking forward to seeing blue sky.
 
From the map, it looks like the 90 is out to lunch, surrounded by mid 70s to low 80s. Also, the 88 up in east central IL is highly questionable given the surrounding observations.

That 88F dewpoint is in Rantoul, Illinois, an observation site that usually reports dewpoints 4-9 degrees higher than other sites in east-central IL. It's sited at Rantoul National Aviation Center on the SE side of town, but I don't know how that would affect its readings. (And one would expect it to have been recalibrated over the last 10 years, no?)

An old topo map, from the days when the site was Chanute Air Force Base indicates a golf course to the east of the site and small hills (10-30 m) around the town to the N, W and NE, with the highest hills to the northeast. Later on that page, you'll see that it's believed the sensor needs recalibration. I could not find a similar page for Mt. Vernon, but at 0500Z July 25 the sensor reported its region's lowest dewpoint.
 
Having lived there, I seem to recall there may be corn fields about a mile to the west and southwest. Not sure if it's enough to affect the readings though.

Tim
 
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