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gsytch

Persistent Cold Air in Florida

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Walt

Due to relatively high dew points here in Florida (say, as compared to the southwest USA where it tends to be more semi arid), most of what folks refer to as frost in my environs is really black ice. Black ice is merely frozen dew.

Technically, frost only forms below the "frost point" (via sublimation, going from a gas, directly to a solid) which is below 32F degrees, whereas dew forms above 32F degrees (on leaves, roof tops, etc.) and then freezes to what looks similar to frost, once the surfaces it's residing on reaches 32F degrees ( a 3-step process, going from water vapor [gas], to water [liquid], to a solid [ice]).

Generally, I've read that black ice is more harmful to plant foliage than frost -- all other conditions being equal.

On some radiational cooling nights I've seen black ice form on flat surfaces when the ambient air temperature was actually in the high 30sF -- as war_eagle explained,i.e., exposed flat surfaces facing more directly to the open sky lose their heat much faster than the surrounding air.

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amazondk
The timing of temps, rain, sun and wind......have been in my favor as far as last night, today and tonight.....feel bad for you further down the state who are ending your rain and getting cold tonight.....there may be some frozen rain on some palms in the state tonight.....my sympathies.

I voluntarily soaked my yard today.....ran the sprinklers for quite a few hours. I figured the palms would like to be well hydrated before getting frozen :blink:

Boy Larry that sounds like a last meal before the firing squad. I hope it did not get that bad.

dk

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gsytch

It is now sleeting out in my back yard. Temp 37.2F and sleet is FALLING. On my patio there are ice pellets accumulating lightly. This will surely go down as a major freeze. The pitter patter of sleet is NOT a sound I ever dreamed of here in Tampa Bay! Greg :o

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spockvr6
For instance, most people in the humid south have seen nights where the air temp, which is taken about 5 feet above ground level in open air, may be 36-38 with a dew point of 28 and yet rooftops and cars are covered in frost. The surfaces of rooftops and cars radiate their heat much faster than surrounding surfaces and the temperature of the air right around the rooftop and car has dropped to 28, and thus the moisture in the air has become a solid, frost. When frost has formed you can be sure that the air in the immediate area of the frost has reached it's dew point and is <= 32F.

Ive actually measured this on a few occasions with a very fine gauge thermocouple that I was able to use to measure the sirface temperature of a car roof on a clear night.

When the air was ~40F, I measured the car roof as having a surface temp of ~33F! It was right on the cusp of being slushy!

One can assume skyward facing leaf surfaces are analogous......they can easily be colder than the actual air temperature around them due to radiational heat losses.

Also, on dead calm nights, there can be a tremendous temperature gradient. On one occasion 4-5 years ago which I remember well, I measured ~34F at 5-6 ft (which is where official readings are taken), and 28F right at the ground. So, any plants which were down there would have seen a much colder temperature than the "official" reading would have indicated.

Edited by spockvr6

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spockvr6
The timing of temps, rain, sun and wind......have been in my favor as far as last night, today and tonight.....feel bad for you further down the state who are ending your rain and getting cold tonight.....there may be some frozen rain on some palms in the state tonight.....my sympathies.

I voluntarily soaked my yard today.....ran the sprinklers for quite a few hours. I figured the palms would like to be well hydrated before getting frozen :blink:

Boy Larry that sounds like a last meal before the firing squad. I hope it did not get that bad.

dk

Good analogy!

Im not sure if this is bad or not....but its 35F and is raining here!?!?!?!? Never have I seen such!

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spockvr6
It is now sleeting out in my back yard. Temp 37.2F and sleet is FALLING. On my patio there are ice pellets accumulating lightly. This will surely go down as a major freeze. The pitter patter of sleet is NOT a sound I ever dreamed of here in Tampa Bay! Greg :o

Greg-

I am colder than you, but seeing rain. I just walked outside (almost hoping for ice to be falling, just to say Ive experienced it), but it was just cold water :blink:

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spockvr6
I believe this cold spell is going into the infamous freeze hall of fame: The Freeze of 2010!

Granted, the minimum is not as bad as '89 or '62, but as far as freeze damage is concerned, it will be bad. Not to mention the very possible sleet/snow flurries in central Florida.

Quite true! A "freeze" to call the worst in some respects. We've rooting for Florida [sadly Texas is already a loss :o

I tend to watch the Galveston,TX temps closely as so many times, what is experienced there with regard to lows on a given cold event is not terribly far off what Tampa Bay sees the next day.

I see Galveston is sitting at 25F and still dropping this AM and therefore, unless something changes, this is approximately what I might need to expect here.

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spockvr6

Might I need to change my signature to 9a/9b from 9b/10a?!?!?!?!??!

LOL

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gsn

I was WRONG about the precipitation, was SLEETING pretty heavily here just a few minutes ago...currently 35.9F here!

Kinda wierd hearing the ice hit palm fronds!

Edited by gsn

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Zeeth

No sleet, but raining at 35F. This REALLY IS a "California winter"

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Tyrone

Reading this thread has gone from being merely painful to excruciatingly agonising. SLEET!!!!!!! Ice hitting palm fronds!!!!!!!!! 35F and rain!!!!! That is something I've never experienced either and never want to see in my area ever. I would be either panicking, or just totally resigned to the damage in a state of silent shock. I'd have a stiff drink, and hope I'd fall asleep and wake up when the sun comes out.

Either that or I would have set up large gas powered fans to blow hot air through the yard.

I'm beginning to fear what winter will hold for us in 6 months.

Best regards

Tyrone

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spockvr6

Deleted....attachments too small

Edited by spockvr6

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SunnyFl
Reading this thread has gone from being merely painful to excruciatingly agonising. SLEET!!!!!!! Ice hitting palm fronds!!!!!!!!! 35F and rain!!!!! That is something I've never experienced either and never want to see in my area ever. I would be either panicking, or just totally resigned to the damage in a state of silent shock. I'd have a stiff drink, and hope I'd fall asleep and wake up when the sun comes out.

Either that or I would have set up large gas powered fans to blow hot air through the yard.

I'm beginning to fear what winter will hold for us in 6 months.

Best regards

Tyrone

There's an unfortunate possibility that you could get a bit of this 6 months from now. Only thinking this b/c of how widespread the cold is - TWC is calling it the "Arctic Blast" - it's not only all over the US, but Europe is having a terrible time, with bad, maybe record, snowfalls everywhere.

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gsn

forecast for tonight from the NWS for Titusville...

Tonight: Partly cloudy, with a low around 28. Northwest wind between 10 and 15 mph, with gusts as high as 20 mph.

if this forecast is right, looks like this will be an ADVECTIVE event rather than radiational!

Edited by gsn

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spockvr6

Here it comes.......looks like its right on that classic 45 degree angle.

post-200-1263043555_thumb.jpg

Edited by spockvr6

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cobra2326

It's sleeting here. 33F and falling... The bottles have been under a tarp all night, with a heater under there. Hopefully it stops raining/snowing/whatever they call it up north so I can protect the foxtail and king.

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cobra2326
Reading this thread has gone from being merely painful to excruciatingly agonising. SLEET!!!!!!! Ice hitting palm fronds!!!!!!!!! 35F and rain!!!!! That is something I've never experienced either and never want to see in my area ever. I would be either panicking, or just totally resigned to the damage in a state of silent shock. I'd have a stiff drink, and hope I'd fall asleep and wake up when the sun comes out.

Either that or I would have set up large gas powered fans to blow hot air through the yard.

I'm beginning to fear what winter will hold for us in 6 months.

Best regards

Tyrone

There's an unfortunate possibility that you could get a bit of this 6 months from now. Only thinking this b/c of how widespread the cold is - TWC is calling it the "Arctic Blast" - it's not only all over the US, but Europe is having a terrible time, with bad, maybe record, snowfalls everywhere.

Let's hope not. If Tyrone's lowest ever was -0.7C, then I doubt they would experience conditions like these. I know pinellas recorded 19F at one point (maybe 89), so it's happened before here, and worse. Brooksvilles record was 12F, so I better not get anywhere near that or even the Chinese fans will be dead.

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gsytch

Jon- I cannot even THINK you are trying to grow stuff like that up there! I teach at Hudson Middle School, about a few miles south of the hernando line, and so much freezes there every year. It is sleeting again here, 36.1F...awaiting a snowflake? Greg :violin:

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sarasota alex

Was 36 at 8AM outside. Now it's 34 at 9:20. Good thing the rain is not freezing.

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cobra2326
Jon- I cannot even THINK you are trying to grow stuff like that up there! I teach at Hudson Middle School, about a few miles south of the hernando line, and so much freezes there every year. It is sleeting again here, 36.1F...awaiting a snowflake? Greg :violin:

Haha, I'm still in denial. Every year, some random people always plant Adonidias, foxtails, etc. only for them to melt away come winter. I build tents around the King, Foxtail and Bottles and run heaters when it gets below freezing, so they've all been in the ground a few years now. Other stuff stays in pots and comes into the heated sunroom when it gets below 40F. To me, this event is just longer than others...

Still, I grew up in clearwater and could have cared less about plants then. Now that I'm interested, I'm stuck up here... Major microclimate envy!

I'm beginning to worry about prolonged cold rather than freeze being a problem. Usually I protect stuff to keep it free from spotting, etc. This year I just want something other than total defoliation.

Edited by cobra2326

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JayW

My neighbors said that they woke up at 3:30 am and went outside and it was snowing... more like flurries, said if you held your hand out, they melted the second they hit it, but you could see it in the air, just not on the ground. They have our low for 22 or 23 tomorrow, but I know that we'll likely see teens out here, maybe lower than the 19.6 earlier in the week. I'm mostly worried about my Silver Bizmarkia and my Silver Serenoa Repens. The Bizmark still looks fine, but the Serenoa Repens have spots on them now. Here's a pic of one of them, the morning we hit 19.6*...

DSCF1122.jpg

Edited by JayW

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cfkingfish

I have 38 persistent in my yard, and dropping, kinda ridiculous. I am going outside, I have two planted palms I want to survive, I am good with the others. It will be hard to cover tonight, I don't even see a reason with those winds.

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redant

How to feel good about forecast lows of 31-35 for tonight, go to bed last night with forecast lows for tonight of 26. Needless to say it was hard to get a good nights sleep last night. Presently in the mid 40's and disgusting out.

Edited by redant

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palmislandRandy

The projected low Sunday 7:00 am in South Palm Beach County has risen from 31 to 34! :blink: Am I supposed to feel relieved??? Hang in there my northern palmys!

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palmislandRandy

When the rain stops, is it a good idea to hit the crowns with a pre-emtive spray of a fungicide?

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Trópico

Freezing rain right at this minute! NW Orlando... 10:15 AM. Local Temp 32°F.

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gsytch

Still sleeting at 10am.. temp fell to 35.0F HORRIBLE I am watching my yard melt in front of my eyes. EVERYTHING is showing damage except for the most hardy palms. :-(((((((((((((((((((((

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Trópico

Sleet at 10:30 AM. Collapsed fronds on Hyophorbe verschaffeltii and Dypsis cabadae. Trying to protect their bases the best I can.

Edited by Trópico

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cobra2326

We're no longer getting sleet here, just plain rain... Maybe it's 32.1F? lol

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BS Man about Palms
Might I need to change my signature to 9a/9b from 9b/10a?!?!?!?!??!

LOL

Larry, I changed mine in Jan 2007 from 10b to 10a... :(

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Walt

All morning it's been raining lightly here and the temperature is 36.7F degrees at 10:40 a.m.

I desparately want the rain to stop and the water to dry up so I can re wrap my tender palms before the temperatures drop below freezing.

Thus far I've protected them from two back to back nights of 28.9F degrees. But it may be all for naught if I can't get them re wrapped. I have heating cables wrapped around the palms and the wraps hold enough heat in that they will not get cold damaged.

This is the first time in 13 years that it has ever rained so that I am unable to wrap my palms because they were wet. Further, this is the first time in the 13 years I've lived here that the temperature is forecasted not to get out of the low 40sF. The lowest high I recall ever having here was 49 degrees, and I think that was back in January of 2001 the day proceeding the lowest low temperature I ever recorded here close to the house, 22 degrees.

AdonidaFP.jpg

Un wrapped Adonidia palm. This palm got totally defoliated last January because I was too lazy to wrap it.

AdonidaFP1.jpg

Adonidia palm with bundled fronds to reduce girth. EasyHeat heating cable spirally wrapped, starting from fronds, down past growth bud, crownshaft (covered with terry cloth towel to prevent scorching, but cables don't hurt foliage, trnk, etc.) and trunk.

AdonidiaFP2.jpg

Adonida palm over-wrapped with quilted mattress covers for insulation to hold in heat from heating cables. Over the years, regardless of how cold it got, my wrapped palms, with heating cables, have never been cold damaged

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happ
No sleet, but raining at 35F. This REALLY IS a "California winter"

Hate to say it but "raining at 35F is not a California winter" [more like Oregon I'm afraid]. :wacko:

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redant

When you have so many palms it's hard to get excited about wrapping any, just not enough time or materials to make a big difference, it kind of sucks.

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Alicehunter2000

Man.......I'm feeling really bad for you folks to my east and south. Yesterday I had the bad feeling that what happened with the perfect timing of weather events that kept me relatively ok, was going to be bad for you all. I didn't really think it was going to be THAT bad. What ya'll are describing is horrific palmwise.........freezing rain! sleet! in Tampa ( and other areas down there)......that is just freakishly bad.

I feel horrible for saying, but events for me (weatherwise) have turned out just about perfect (as cold weather can be) for my area. We dried out pretty much from the night before (and got some much needed water) Then we had cloud cover all night last night (no rain) and light winds, temps didn't drop below 26.........much better than expected. Now as if right on cue this morning the clouds are being replaced by clear skies at 10:00 am with light winds. Should warm up substantially. Still not sure how low it will get tonight, but since it is a Saturday, I have all day to string a few Christmas lights and prepare.

I really feel fortunate up here but I feel extremely bad for you all. The real tragedy is that we always know up here to expect a really bad freeze every few years (and plant pretty hardy stuff). But ya'll have all that beautiful tropical-like foliage that is really getting hammered. I go down every year for convention to Orlando, St. Pete and/or Miami etc. It will be heartbreaking to see the damage.....(not to mention the financial costs associated with this freeze).

Good luck to you all tonight.......clear skies just beginning at 10:00 am up here.....temps around 30-32......plan your day accordingly wherever you are. This is what's coming next.

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Zeeth

I wrapped my coconut last night. It's still raining and cold. I removed the sheets and blankets from it, but should I untie all the fronds too? Also, should I remove the christmas lights?

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spockvr6
I really feel fortunate up here but I feel extremely bad for you all.

Save the condolences for a few days! The next two nights are going to be the worst for everyone.....north to south, if the forecasts are even remotely accurate.

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Alicehunter2000

Larry, I have the feeling you are right. I'm glad it is Saturday and I don't have to work. I am going to spend the day putting Christmas lights on the Bizmarkias and wrapping the spears on the queens.........I haven't gone below 25 up here yet.....but the sky is blue, blue, blue and I got a feeling tonight is going to be cold,cold,cold. Thanks for extra warning......I think my luck is running out.

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PalmatierMeg

"Well, I never felt more like singing the blues,

'cause I never thought that I'd ever lose

my dear palms"

10 a.m. - 39.6 and rain

11:15 - 40.6 and rain

11.45 - 40.3 and rain

Stop raining, dammit!

Sorry.

How can I cover my palms unless the rain stops and the sun comes out to dry them? In all my years in FL I've never seen it rain at 50F or less. Low tonight is forecast to be 31. I can tell from experience (forgotten irrigation) that wet palms + freezing temps = Death.

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spockvr6
Larry, I have the feeling you are right. I'm glad it is Saturday and I don't have to work. I am going to spend the day putting Christmas lights on the Bizmarkias and wrapping the spears on the queens.........I haven't gone below 25 up here yet.....but the sky is blue, blue, blue and I got a feeling tonight is going to be cold,cold,cold. Thanks for extra warning......I think my luck is running out.

Its funny how blue skies are normally so enjoyable.......just not right now :mrlooney:

We are still completely clouded over down here, but obviously this will change in time. The temp is not really wamring up at all, so unless something changes dramatically, I dont see how it will get much above 40F.

For my area, if the winds stay N/NW, there will be some possibility of being spared. If not......good night Irene!

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redant
[i]"Well, I never felt more like singing the blues,

'cause I never thought that I'd ever lose

my dear palms"

10 a.m. - 39.6 and rain

11:15 - 40.6 and rain

11.45 - 40.3 and rain

Stop raining, dammit!

Sorry.

How can I cover my palms unless the rain stops and the sun comes out to dry them? In all my years in FL I've never seen it rain at 50F or less. Low tonight is forecast to be 31. I can tell from experience (forgotten irrigation) that wet palms + freezing temps = Death.

I'm thinking keep raining, keep the cloud cover for as long as possible, might be the only thing that spares me. I could be wrong on this but I can't wrap so KEEP THE CLOUDS PLEASE.

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