* User

Welcome, Guest. Please login or register.

Login with username, password and session length

Advertisement


Author Topic: October 2020  (Read 4457 times)

0 Members and 1 Guest are viewing this topic.

Offline Thundersnow

  • Administrator
  • Tornado
  • ******
  • Posts: 11,827
  • Location: Nolensville
  • Liked:
  • Likes Given: 549
Re: October 2020
« Reply #45 on: October 16, 2020, 11:48:54 AM »
Frost advisories are going up for tonight and tomorrow morning.

Offline gcbama

  • Derecho
  • ******
  • Posts: 1,225
  • Location: Lewis County Tn
  • Liked:
  • Likes Given: 3
Re: October 2020
« Reply #46 on: October 16, 2020, 01:16:32 PM »
Frost advisories are going up for tonight and tomorrow morning.

this may be a dumb question....how cold do temps normally have to be for frost to form?

Online TNHunter

  • Severe Thunderstorm
  • ****
  • Posts: 409
  • Location:
  • Liked:
  • Likes Given: 1
Re: October 2020
« Reply #47 on: October 16, 2020, 02:03:17 PM »
this may be a dumb question....how cold do temps normally have to be for frost to form?

32 degrees lol the freezing point of water.  Many people think it can form at higher temperatures because they see frost when the low was only 38 or whatever.  Where you see frost, the temperature on the surface of that material is 32 degrees.

I have heard of a lot of old timers talking about the poison in frost that kills plants lol.  They water their plants early in the morning to "wash off the poison" lol.  Old sayings
« Last Edit: October 16, 2020, 02:05:46 PM by TNHunter »

Offline BRUCE

  • Tornado
  • ******
  • Posts: 8,079
  • Location: Spring creek
  • home of three ef4 tornadoes since 1999
  • Liked:
  • Likes Given: 2258
Re: October 2020
« Reply #48 on: October 16, 2020, 02:05:21 PM »
32 degrees lol the freezing point of water.  Many people think it can form at higher temperatures because they see frost when the low was only 38 or whatever.  Where you see frost, the temperature on the surface of that material is 32 degrees.
i have seen frost form at 36 degrees. F
Come on severe wx season...

Online TNHunter

  • Severe Thunderstorm
  • ****
  • Posts: 409
  • Location:
  • Liked:
  • Likes Given: 1
Re: October 2020
« Reply #49 on: October 16, 2020, 02:06:34 PM »
Did you actually take a temperature reading at the surface where the frost was?  If you see frost and the air temperature is only 36-38 that doesn't mean at the surface of the material with frost isn't 32.  Cold air is more dense than warm air so it sinks.
« Last Edit: October 16, 2020, 02:09:46 PM by TNHunter »

Offline Thundersnow

  • Administrator
  • Tornado
  • ******
  • Posts: 11,827
  • Location: Nolensville
  • Liked:
  • Likes Given: 549
Re: October 2020
« Reply #50 on: October 16, 2020, 02:12:50 PM »
Frost can form with air temperatures above freezing, into the upper 30s.

I think it's a radiational cooling thing... exposed surfaces can actually cool below the ambient air temperature. Someone else might provide a more precise answer.
« Last Edit: October 16, 2020, 02:17:25 PM by Thundersnow »

Offline Crockett

  • Administrator
  • Tornado
  • ******
  • Posts: 3,542
  • Location: Oneida, TN
  • Liked:
  • Likes Given: 42
Re: October 2020
« Reply #51 on: October 16, 2020, 05:46:57 PM »

I have heard of a lot of old timers talking about the poison in frost that kills plants lol.  They water their plants early in the morning to "wash off the poison" lol.  Old sayings

Don't laugh. It might not be poison but it works. When I put out my garden too early and there's frost in the forecast, I have actually turned on my sprinklers to keep frost from forming and killing the plants. Obviously that's not going to work if temps are cold enough for falling water to freeze on contact, but if that's the case then we're dealing with a freeze advisory/warning rather than a frosty advisory and that's gonna be an entirely different animal.

Online TNHunter

  • Severe Thunderstorm
  • ****
  • Posts: 409
  • Location:
  • Liked:
  • Likes Given: 1
Re: October 2020
« Reply #52 on: October 16, 2020, 07:08:59 PM »
Don't laugh. It might not be poison but it works. When I put out my garden too early and there's frost in the forecast, I have actually turned on my sprinklers to keep frost from forming and killing the plants. Obviously that's not going to work if temps are cold enough for falling water to freeze on contact, but if that's the case then we're dealing with a freeze advisory/warning rather than a frosty advisory and that's gonna be an entirely different animal.

I agree it does work, just thought the poison part was funny

Offline gcbama

  • Derecho
  • ******
  • Posts: 1,225
  • Location: Lewis County Tn
  • Liked:
  • Likes Given: 3
Re: October 2020
« Reply #53 on: October 16, 2020, 10:19:29 PM »
Frost can form with air temperatures above freezing, into the upper 30s.

I think it's a radiational cooling thing... exposed surfaces can actually cool below the ambient air temperature. Someone else might provide a more precise answer.

SO basically a freeze advisory means all ground surfaces will be at 32 or below and a frost advisory would mean some surfaces will be at 32 just not everything i gather is what the advisories mean? Always wondered why frost advisory would be issued for temps at 35-38 degrees

Offline Coach B

  • Derecho
  • ******
  • Posts: 2,138
  • Location: Marshall County
  • Liked:
  • Likes Given: 248
Re: October 2020
« Reply #54 on: October 17, 2020, 06:42:09 AM »
SO basically a freeze advisory means all ground surfaces will be at 32 or below and a frost advisory would mean some surfaces will be at 32 just not everything i gather is what the advisories mean?

They issue the freeze advisories when they expect the actual reported air temps to be below freezing throughout the area in question.

Offline Thundersnow

  • Administrator
  • Tornado
  • ******
  • Posts: 11,827
  • Location: Nolensville
  • Liked:
  • Likes Given: 549
Re: October 2020
« Reply #55 on: October 17, 2020, 07:00:18 AM »
SO basically a freeze advisory means all ground surfaces will be at 32 or below and a frost advisory would mean some surfaces will be at 32 just not everything i gather is what the advisories mean? Always wondered why frost advisory would be issued for temps at 35-38 degrees

Freeze warning is when near or sub-freezing air temperatures are expected for a period of time, which means there’s depth to things freezing... it’s penetrating. Frost advisories are issued when air temps are expected to remain above freezing, but frost may form on surfaces, which is a risk for the most sensitive plants. The difference is- it’s very “surface-y.”

Think of it like the difference between a plant getting some of its leaves damaged by frost forming and a freeze outright killing a plant because it froze within its stems to the core.

Offline JHart

  • TNWX Supporter
  • Supercell
  • ******
  • Posts: 507
  • Location: Lascassas (NE Rutherford County)
  • Liked:
  • Likes Given: 145
Re: October 2020
« Reply #56 on: October 17, 2020, 11:28:49 AM »
This morning, the temperature dropped to 30F in the creek bottom about one hundred feet away from the house.  We had a heavy frost on the grass, but latent heat from the bricks and sidewalk protected the weary summer annuals.

Time for one final mow this afternoon before I surrender the yard to wild onions until April.
Hire the left-handed --- its fun to watch them write.

Offline schneitzeit

  • Derecho
  • ******
  • Posts: 1,809
  • Location: Nashville, TN, 37211
  • Liked:
  • Likes Given: 1570
Re: October 2020
« Reply #57 on: October 18, 2020, 12:13:22 PM »
12Z Goofus puts our first snowstorm on the map 10 days from now. Lol
.

Offline Clarksville Snowman

  • Derecho
  • ******
  • Posts: 2,332
  • Location: Woodlawn
  • Liked:
  • Likes Given: 2033
Re: October 2020
« Reply #58 on: October 18, 2020, 01:33:32 PM »
Yep just seen that, I do think the midwest has a good chance. Would be nice to get a good snowpack to the northwest early in the year with staying power. But keeping it there without a quick melt is the concern, especially this time of year. The last snow in october in my area that actually covered the ground was Halloween of 1993, the first year I moved into woodlawn. It covered the grassy areas and most stayed on the ground through the next day. I remember when I was around 5 years old, I think it was 1969 that we had 3-4 inches on the ground Halloween night it snowed all day long and quit around dark. I remember the roads were slushy but the grass was covered. It can snow that early but it's rare and it's been awhile. But there have been a few good snows in early november if you go to the record books. ::snowman:: ::snowman:: ::snowman::

Offline BRUCE

  • Tornado
  • ******
  • Posts: 8,079
  • Location: Spring creek
  • home of three ef4 tornadoes since 1999
  • Liked:
  • Likes Given: 2258
Re: October 2020
« Reply #59 on: October 18, 2020, 02:24:34 PM »
12Z Goofus puts our first snowstorm on the map 10 days from now. Lol
not happening ... lol
Come on severe wx season...

 

* Recent Posts

Hurricane Zeta
by TNHunter
[Today at 09:08:52 AM]
October 2020
by TNHunter
[Today at 05:53:24 AM]
Long Range Discussion: Winter 2020-2021
by Coach B
[October 26, 2020, 09:35:20 PM]
2020 Tropical Season Outlook
by dwagner88
[October 26, 2020, 09:12:02 PM]
Fall 2020: Because Fall Comes Before Winter
by Greyhound
[October 22, 2020, 10:58:15 AM]

Advertisement