Nine percent humidity today

[230RN]

https://forecast.weather.gov/MapClick.php?lat=39.7836&lon=-105.1675&unit=0&lg=english&FcstType=graphical

(Current for when you click on it. Nine percent around 3 PM MDT.)

You gots to drive two-three miles before bumping into a water molecule.

Eyeball shriveling, nose-pickin' time.  But good for guns, swamp coolers, drying laundry.

Probably bad for fire danger ratings.

Beef jerky can be made by leaving a slice out for half an hour.

"Wet your whistle" becomes a meaningless term.

Deodorant spray dries before it hits your armpit; spit don't hit the ground.

Dead things don't decay, they just mummify.

I remember being surprised to see "bone dry" iused as a technical term on a lecture bottle of "Bone Dry Carbon Dioxide."   Sample: https://www.airgas.com/product/Gases/Specialty-Gases/Carbon-Dioxide---Specialty-Gas/p/CD%20BD200

"But it's a dry heat..."  Yeah, but holy crap, nine percent?

Terry, 230RN

Edited to change sry heat to dry heat.

[MechAg94]

Sounds like when I was at a site near Las Vegas about this time last year.  For someone who lives on the Texas Gulf Coast, that is just alien.  Dry is 60% down here. 

When I drove back into Texas, it was great to see clouds, green grass, and feel moisture on my cheek. 

[WLJ]

Just checked my weather station, 57% here in Louisville. Sort of dry and zero chance of rain most of the week which is unusual for this time of year here.

[RoadKingLarry]

89% here this morning.

[230RN]

57%?
89%?

That's percentage saturation of water vapor, real water, H₂O, right?  Holy cow, how come youse guys ain't drowning in your own air?

I saw wind velocity was actually zero about an hour ago.  Verrry rare, but off the graph by now 7:25 AM MDT.

Cue Twilight Zone theme.

[WLJ]

Last 30 & 90 days

[Nick1911]

57%?
89%

That's percentage saturation of water vapor, real water, H₂O, right?  Holy cow, how come youse guys ain't drowning in your own air?

I saw wind velocity was actually zero about an hour ago.  Verrry rare, but off the graph by now 7:25 AM MDT.

Cue Twilight Zone theme.

It is not.

It is the percentage of water vapor in the air relative to what the air can hold at that temperature.

As it gets warmer, air can hold a lot more moisture.  This is why relative humidity is somewhat misleading.

If you want to know absolute humidity, that's typically given in grains per pound of air, in US customary units.

At 40F, air can hold about 38 grains of water per pound.  At 90F, it can hold north of 210 grains per pound.

If the total amount of water in the air stays constant and the temperature increases, RH% will drop.

https://www.engineeringtoolbox.com/docs/documents/816/psychrometric_chart_29inHg.pdf

X axis is temperature, Y axis is absolute humidity.  Note the RH% lines that curve through the chart.

[HankB]

When I was last in Tucson, temperatures were in the 104-106 F range, and dewpoints were in the 20s. It didn't feel terribly hot - in fact, it was almost pleasant. Sun was pretty intense, though. Some restaurants with outdoor seating had misters going, which helped cool things down a little, even in the shade.

Here in central Texas (Austin area) when we're in the low 100s, dewpoints - even in the middle of a drought - are typically above 60, sometimes edging into the 70s. THAT feels unpleasant - when you sweat up, you stay damp as long as you're outside.

[230RN]

It is not.

It is the percentage of water vapor in the air relative to what the air can hold at that temperature.

As it gets warmer, air can hold a lot more moisture.  This is why relative humidity is somewhat misleading.

If you want to know absolute humidity, that's typically given in grains per pound of air, in US customary units.

At 40F, air can hold about 38 grains of water per pound.  At 90F, it can hold north of 210 grains per pound.

If the total amount of water in the air stays constant and the temperature increases, RH% will drop.

https://www.engineeringtoolbox.com/docs/documents/816/psychrometric_chart_29inHg.pdf

X axis is temperature, Y axis is absolute humidity.  Note the RH% lines that curve through the chart.

I knew that.  Just minimalized it so I wouldn't trash up my post for the sake of the humor.

No offense, but that's pretty standard knowledge, and I've explained it myself a couple of times but thanks for the definitive explanation.

I was interested to note that WLJ's graphs inclided a confidence band.

Terry

[Nick1911]

Ah, guess that joke went over my head.  Better drink some more coffee before posting. 

I sometimes forget that standard knowledge in this group is leaps and bounds ahead of the general population.

[WLJ]

Temps last 30 days, includes dew points

[RoadKingLarry]

57%?
89%?

That's percentage saturation of water vapor, real water, H₂O, right?  Holy cow, how come youse guys ain't drowning in your own air?

I saw wind velocity was actually zero about an hour ago.  Verrry rare, but off the graph by now 7:25 AM MDT.

Cue Twilight Zone theme.

This time of year we measure our morning dew fall in inches.

[Brad Johnson]

Texas Tech has a series of weather stations dotted around the region - Texas panhandle and Rolling Plains areas. Realtime readings (well, every few minutes, anyway...). Great for tracking common meteorological info.

https://www.mesonet.ttu.edu/

They also have a radar page which is much less bloated than the new NWS product. More like the old WSR88D page.

https://www.mesonet.org/index.php/weather/radar/KLBB

Brad

[JTHunter]

Here's another example of RH for you.
On 6/2/76, I was on a zoology field trip from my university and we were entering Joshua Tree Natl. Monument.  The bus boiled over on the way in and, as it turned out, the park office was already closed for the summer!  A bunch of us went climbing on the rock piles (200-300' high) near where the bus had to stop and two groups raced up two of these piles to see who got to the top first.  While it was fun, we all ended up winded and sweaty.  We went over and stood in the shade of the bus and there was a slight breeze, maybe 3-8 mph.  Within 10 minutes, we were cooled off and dry again.  The prof estimated the RH at ~5% at the time. 

[230RN]

There have been days where I didn't have to use a towel after a shower.  I did, out of habit, but I didn't have to.

Not much trouble with humidity-caused gun rusting here in Commierado.

A little different from NYC, where I was born and raised.  We didn't have guns, but tools would rust no matter what you did.  It seemed the salt air didn't help; salt spray from the ocean waves would evaporate, leaving teeny-tiny particles of sea salt to blow around.  Salt + tools + humidity = rust.

Terry

REF (Corrosion due to humidity): 
Hatcher's Notebook says a great deal about humidity in his chapter on "Gun corrosion and ammunition developments."

One of the things that drove the Ordnance Department nuts with regard to the old corrosive primers was the fact that sometimes barrel corrosion developed weeks after thorough cleaning, sometimes it didn't.  The mystery was solved when it was discovered that humidity over 50% caused it, and that percentage of humidity might not be reached for a random time after the cleaning.  See pages 348-349, Hatcher's Notebook

[Brad Johnson]

If it's any consolation, it's snowing in Fraser / Winter Park today.

https://youtu.be/hQeFtIAmlqQ

Brad

[230RN]

^
Well, at 8700 feet, Fraser's kind of "across the (vertical) 'border' " of about 6500 feet, more or less.

In fact, it's snowing pretty good here near Golden at ~5600 feet.

Fun at night shining a laser out into the falling flakes.  Discovered that one night by trying to take the air temperature with my IR sensor which has a laser beam on it.

Sample:

   

"Ooooo !  Sparkles !  Eeeeee !  Pretty !"  Don't have little ones around but the kiddies would probably love it.  (Yeah, even this 84yo kid.)

Don't use the lasers on your gun sights.<"Legal" advice just to cover my own ass.

Terry, 230RN

REF (Current for when you click on it):
https://forecast.weather.gov/MapClick.php?lat=39.7836&lon=-105.1675&unit=0&lg=english&FcstType=graphical

[Perd Hapley]

We had a funeral in Urbana IL this morning, and were leisurely making our way back. We were coming south from Springfield, and as soon as we got onto 270 West, toward St Louis, we heard a tornado warning. Didn't have any place to go, so we eventually parked under a gas station canopy, and came inside. Or at least, the wife is inside. I'm right outside the door, watching. Nothing but rain, so far.

Back on the road now.

[230RN]

Just a warning?  I wouldn't have taken evasive / sheltering action unless one was visible.  At least in a vehicle, you can try to head at right angles to its perceived path. Or possibly outrun it.

Opposing views?  Enlighten me, please.

Yeah, some guys got killed in a car, but they were storm chasers and deliberately placed themselves in danger and got themselves stuck in an inescapable situation and the car went bouncity bouncity bouncity with them inside going thumpity thumpity thumpity --although I think IIRC, one got ejected from the car while it was going bouncity bouncity bouncity.

Tragic, but I feel as bad for them as I would for a skydiver whose 'chutes didn't open.  Splattery splattery splattery.  Or a technical rock climber who lost his its her grip. Tumblity tumblity tumblity.  Owie owie owie.  Recovery recovery recovery by helicoptery.

Terry, 230RN

[RoadKingLarry]

A "warning" means there is an active tornado in the vicinity. That means it's time to get the cameras out  .

Can't always see 'em coming. At night unless you see the power flashes where it's taking out the lines or if it's rain wrapped you might not know it's on you till you are well on your way to The Land of Oz.

[Perd Hapley]

Just a warning?  I wouldn't have taken evasive / sheltering action unless one was visible.  At least in a vehicle, you can try to head at right angles to its perceived path. Or possibly outrun it.

Opposing views?  Enlighten me, please.

"Just a warning" means you're in more immediate danger than a "watch." It means you should get in the cellar. (Or get the camera, cuz something might go down real soon.)

 I once had the pleasure of being on the freeway, going right past Lambert Field, right around the time it was being wrecked by a twister. Got no desire to relive the experience, in the middle of featureless Illinois farmland, where there's nowhere to hide.

[RocketMan]

Just a warning?  I wouldn't have taken evasive / sheltering action unless one was visible.  At least in a vehicle, you can try to head at right angles to its perceived path. Or possibly outrun it.

Opposing views?  Enlighten me, please.

Terry, 230RN

You should seek shelter, not try to outrun a tornado in a car.  Why, you ask?  Lots of high falutin' reasons given in our storm spotter and chasing training, all boiling down to that in a car you are limited by where the road network goes, by the other panicky fools out there driving with you, and by the tornado's unpredictable behavior.
The road network often does not go where you want it to when the tornado is trying to climb into your trunk.  This should be self-explanatory.
Panicky fools have a very annoying tendency to do foolish and unexpected things as they drive. They turn randomly, crash, clog up the roads, etc., thereby thwarting your best laid plans to drive away from the tornado.
Tornados themselves often change their direction of travel.  When they do, it's frequently a turn to the right.  If you have committed to a direction of travel to skirt around a tornado and then the tornado becomes a "right mover", it can thoroughly ruin your day.
Plus, if the tornado is close by, you have to deal with flying debris, which can be deadly even if you are inside a car.

Edited to add additional info.

[230RN]

WRT^

"...At least in a vehicle, you can try to head at right angles to its perceived path. Or possibly outrun it."

Bolding added.

Well, sure, but your crazy other driver scenario is true anyhow, tornado or no tornado.  And your remark about those tornado chasers is irrelevant since they weren't trying to escape in the first place.

Certainly, your course of action depends on circumstances, but for the general situation, (A) I wouldn't automatically try to shelter up and (B) My perhaps clouded judgement would be to drive away as noted.  I did shelter my camper under an overpass when some really rough weather occurred.  I got there just in time, the underpass filled up with other vehicles in a hurry. Tornadoes out in the boonies aren't necessarily reported on newscasts, but holy crap, the sky sure opened up and there was a roaring sound but that could have been the hail.

Despite the vagaries of tornado direction-taking, if you have any distance from them at all, my estimation is the best bet is to move away from them...the "right angles" has been recommended by Officialdom, for what it's worth.  They aren't looking for Rocket Man, after all.  "Hey, there's Rocket Man's car !  Let's go git 'im!"

But it depends on what you guess your chances are.  Do you hit with 17 in Blackjack?

Perd did not go into great detail on the situation, so his choice may have been perfectly valid, even under a "warning" alert.  I just wanted to comment on the notion that it seemed automatic.  May have been a good choice given the exact situation.

Terry taps his cards.  "Hit me."

Dealer skids card to Terry.  "Oh, *expletive deleted*it. A five."

Terry, 230RN

[Perd Hapley]

The thing is, Terry, when you're heading down the freeway, at dusk, with heavy cloud cover, you don't know if you're heading toward the possible tornado, or away. If it starts to rain, visibility gets worse. And because (again) it's a rural freeway, your selection of "right angles" is limited, if you're not prepared for off-roading.

In fairness, I think I have heard the advice about moving away at a right angle, but I've also heard you should take shelter in a ditch, if you're outside. I'm pretty sure both of those are meant as backup measures, if you can't get into some kind of of structure.

As it happened, the wind got awfully strong, and there was some hard rain for a while. I don't regret being off the road for that. Plus, we had the car under a canopy, in case of hail. Delayed us about an hour, but we were OK with it.

[Ben]

^^^

Sounds like you made all the right decisions for the circumstances. I wouldn't want to be trying to navigate an escape route at nightfall in an unfamiliar area either. Prudence says "first good shelter and call it good". Plus it would have sucked if you had driven away from the tornado and straight into a hailstorm and had that damage to deal with.

Glad you and the Mrs are okay.