First Ground and Air Frost Watch - Season 2023-24

[damianslaw]

It's the 1 September and time for this yearly thread..

Please use it to speculate and record first ground and air frosts.

An air frost is when temps drop below 0 degrees.

Here we don't tend to record our first ground frost until late Sept. 

First air frost by about 3rd week October.

Some Highland glens could record a slight grass frost tonight, but otherwise no chance of frost on the horizon anytime soon.

[Seasonal Trim]

End of September would be fantastic. End of October is more realistic for my area and even that is optimistic.

[Don]

48 minutes ago, Seasonal Trim said:

End of September would be fantastic. End of October is more realistic for my area and even that is optimistic.

Yes, cold nights with slight frosts in September would be great.  The last time I remember air frosts in October was back in 1992.

[sundog]

29 minutes ago, Don said:

Yes, cold nights with slight frosts in September would be great.  The last time I remember air frosts in October was back in 1992.

Did you not get an air frost in late October 2010? 

I remember Autumn 92 having quite a number of  ground frosts. One of my favourite Autumns.  An Autumn that properly felt like Autumn.  From memory decent frosts from late September into  early winter- late December. Although the winter overall wasn't much to write home about.

[Frigid]

Hoping for a frost fest in these upcoming months, mid September onwards. Predicting we see our first air frost at the end of October and our first ground frost sometime in December. 

[damianslaw]

23 Sept 2012 delivered -3 to inland lakeland valleys. Our earliest sharp frost in recent times.

Just now, Frigid said:

Hoping for a frost fest in these upcoming months, mid September onwards. Predicting we see our first air frost at the end of October and our first ground frost sometime in December. 

Assume mean other way round.

[sundog]

Dublin Airport recorded its coldest Oct night only a few yrs ago , think it was in 2020. -2c, nothing spectacular but it isn't far from the coast.

Edit 2018. And 2018 was the last time I recorded an air frost in Oct. 

Edited September 1, 2023 by sundog

[damianslaw]

I see Aboyne went down to 2.8 overnight. Just about grass frost territory.

[Polar Maritime]

-2c last night just outside Corgarff, 2 nights in a row.

[dryfie]

1 hour ago, damianslaw said:

I see Aboyne went down to 2.8 overnight. Just about grass frost territory.

Indeed, 0600 report shows air min of 2.4c and grass -1 (only reported to nearest whole degree).

AAXX 02064

03080 05983 03005 10039 20038 30038 40212 53005 60002 333 10161 20024 3/101 60005 70000 91006 90710 91106=

[cheese]

We normally record our first ground frost in mid/late October, first air frost in mid/late November. Any kind of frost in September is exceptionally rare. 
 

I expect our lowest temperature this month to be around 5-6C. 

Edited September 2, 2023 by cheese

[damianslaw]

6 hours ago, Polar Maritime said:

-2c last night just outside Corgarff, 2 nights in a row.

Is that official? Seems an anomaly..

[jules216]

44 minutes ago, damianslaw said:

Is that official? Seems an anomaly..

Felagie Glen -1.6 Yesterday and -1.2 today. Delachuper near Corgarff today -1.6. I was co-managing the installation using Nasa Landsat maps. Its a ecowit solar GSM station,of course unoficial. Felagie is about 15km NE of Braemar.

[summer blizzard]

I seem to remember that the remains of Ex Hurricane Ophelia in 2005 brought a frost in September 2005 albeit probably not that cold in West Yorkshire. 

[B87]

Average first frost at Heathrow is 22nd November. I think we might even get one in late October this year if high pressure dominates.

[Metwatch]

Lots of personal stations recording an air frost in the Highlands last few mornings. Nothing overly rare at this time of year.

[jules216]

45 minutes ago, Metwatch said:

Lots of personal stations recording an air frost in the Highlands last few mornings. Nothing overly rare at this time of year.

This is Felagie Glen station. Image 3 looking towards west, station is towards 2/3rds bit to the right. I think we didnt nail the spot 100% perfect as there is about 4 mtrs lower altitude we can go. Very rapid cooling 2 nights now where its almost frost before midnight while other cold hollows are about 1.5/2C warmer,then the drop slows and Corgarff or Carrbridge come close within minimas. Might be some valley low cloud or inversion also which slows the absolute drop. But I am happy. Yesterday it was coldest reading measured in whole of UK to date, previous -0.6°C in 2004 elsewhere in Scotland which is UK absolute minima for 1.9.

[jules216]

If anybody is curious, my obsesion changed from long range,GSDM,stratosphere etc. to "Frost Hunting". We have installed about 15 stations now in Slovakia with almost WMO quality readings - Young or Barani radiation shields in frost hollows. Our premier location Poľana can achieve air frost even under +14°C T850hPa with increddibly nearly 15°C inversion. In May we measured -12.8°C about 4°C colder then May offical record in Slovakia below 1000m.asl. Here she is

Edited September 2, 2023 by jules216

[damianslaw]

6 hours ago, jules216 said:

This is Felagie Glen station. Image 3 looking towards west, station is towards 2/3rds bit to the right. I think we didnt nail the spot 100% perfect as there is about 4 mtrs lower altitude we can go. Very rapid cooling 2 nights now where its almost frost before midnight while other cold hollows are about 1.5/2C warmer,then the drop slows and Corgarff or Carrbridge come close within minimas. Might be some valley low cloud or inversion also which slows the absolute drop. But I am happy. Yesterday it was coldest reading measured in whole of UK to date, previous -0.6°C in 2004 elsewhere in Scotland which is UK absolute minima for 1.9.

Thanks, surprised so low and little comment. The forecasts didn't mention any chance of sub freezing. Shows how cool an airmass we've just had. Very under the radar.

[Seasonal Trim]

First frost seems a million miles away atm when we could be looking at 30° over the next few days. Although, wouldn't it be great to go from a mini heatwave to first frost all within September.

 

We can only dream. 

[jules216]

On 03/09/2023 at 01:25, damianslaw said:

Thanks, surprised so low and little comment. The forecasts didn't mention any chance of sub freezing. Shows how cool an airmass we've just had. Very under the radar.

I am sure its because these are not official stations. There was another frost today in Highlands I ve counted 7 station below 0°C in Invernesshire and Aberdeenshire despite T850hPa being +14°C!  It just shows what a carefully considered scientific approach does, re.cold doline placements. Out of those 7 I think at least 5 were installed this year using Landsat Thermal images.

[damianslaw]

Time for this thread to come out of hibernation.. it plays hide and seek in September...

Alas Highland valley spots in the Grampians could drop close to freezing early hours tomorrow, with greater risk early hours Wednesday.

A light grass frost just about possible N Pennine cold spots, Shap and Redesdale Wednesday morning.

Welcome observations next couple of days.

[jules216]

11 hours ago, damianslaw said:

Time for this thread to come out of hibernation.. it plays hide and seek in September...

Alas Highland valley spots in the Grampians could drop close to freezing early hours tomorrow, with greater risk early hours Wednesday.

A light grass frost just about possible N Pennine cold spots, Shap and Redesdale Wednesday morning.

Welcome observations next couple of days.

North of Carrbridge.

[MattStoke]

Common for Scottish glens to have their first frost as early as August.

On 02/09/2023 at 00:14, Frigid said:

Hoping for a frost fest in these upcoming months, mid September onwards. Predicting we see our first air frost at the end of October and our first ground frost sometime in December. 

Going to be difficult to get an air frost without a ground frost....

[johnholmes]

29 minutes ago, MattStoke said:

Common for Scottish glens to have their first frost as early as August.

Going to be difficult to get an air frost without a ground frost....

so difficult it is impossible