Convective/Thunderstorm Discussion : Spring/Summer 2017

Meteorite58

sparrowcar wrote: »

Any upgrade IYO for today/tomorrow Meteorite58?

Well plenty of instability tomorrow, but as Convective Weather says will there be too much cloud cover to get convection going. To me showing the most potential for thunderstorms in quite awhile if there is enough break in the clouds.



Convective Outlook
VALID 06:00 UTC Fri 31 Mar 2017 - 05:59 UTC Sat 01 Apr 2017

ISSUED 18:42 UTC Thu 30 Mar 2017

ISSUED BY: Dan

Upper trough approaching from the Atlantic on Friday will serve to steepen lapse rates as cool air aloft overspreads relatively warm SSTs (and diurnally-heated land). The net result is a few hundred Jkg-1 CAPE, with bands of showery precipitation, perhaps isolated thunderstorms, moving N-wards and E-wards across Ireland into western Britain. Some small hail will be possible in the most intense cells.


Better instability will be found over portions of Ireland, but with the proviso that excessive cloudiness may inhibit convective depth somewhat - hence for now have refrained from upgrading to SLGT. A few heavy showers are possible in E England during Friday afternoon, but convective depth looking marginal for lightning. Also, French exports may get close to SE England during the first half of Friday morning and again late afternoon / early evening.

Meteorite58

Met Eireann going for widespread thundery showers in the afternoon after the initall band of rain clears.

Tomorrow

The last of the rain will finally clear northwards early on Friday. Then the day will brighten with good sunny spells in many places for the morning time. However heavy thundery showers will also break out, these becoming widespread through the afternoon and evening. Highest temperatures of 12 to 15 degrees moderate southwest breezes.

Iancar29

Pulse type storms today. Few sferics possible with the better diurnal heating.
Lack of nearby jet streak however given little to no shear so minimal chance for cells to last/organise.

Comhrá

Interesting how the streamers are forming over the mountains in W.Cork and moving NE in the airflow. Hopefully a few nice thunderstorms in the Southwest and Midlands in the afternoon.

DOCARCH

A couple of sparks now in the Galway and Athlone area: http://brunnur.vedur.is/athuganir/eldingar/i_dag_na.html?

Rikand

3 more rumbles over Athlone just now

Rikand

The dogs are out in the garden and they're hearing the rumbles of thunder a second or two before we are. They're barking at it before it seems to reach

highdef

Rikand wrote: »

The dogs are out in the garden and they're hearing the rumbles of thunder a second or two before we are. They're barking at it before it seems to reach

It must be something else they are barking at. Sound can't arrive at a given location quicker depending on the species of animal hearing it. Maybe some sort of shockwave we can't hear but definitely not the thunder itself

Meteorite58

Lightning activity today, seems to have quietened down now.

Meteorite58

Again showery conditions developing tomorrow, heaviest in the afternoon, this time coming from the NW. Possibility of some lightning. Perhaps Central, East or South East . Shear low again, doesn't strengthen until early evening and by that time most of the showers should have cleared.





EDIT : Update Only 1 sferic showing up. Just off Rosslare in the afternoon.

pedigree 6

highdef wrote: »

It must be something else they are barking at. Sound can't arrive at a given location quicker depending on the species of animal hearing it. Maybe some sort of shockwave we can't hear but definitely not the thunder itself

It could be the thunder that the dogs are hearing? (I'm definitely leaving the question mark there).
It just could be a higher pitch of sound that travels before the lower pitch that humans can hear.

Dogs can hear a frequency of 67 to 45,000 Hz.
Humans can hear 64 to 23,000 Hz.

As an example say the thunder clap starts off at 40,000 Hz and goes down to 10,000 Hz during the rumble.
Humans wouldn't be able to hear the start of the clap (tune) but dogs would? (Again ?)

Gaoth Laidir

pedigree 6 wrote: »

It could be the thunder that the dogs are hearing? (I'm definitely leaving the question mark there).
It just could be a higher pitch of sound that travels before the lower pitch that humans can hear.

Dogs can hear a frequency of 67 to 45,000 Hz.
Humans can hear 64 to 23,000 Hz.

As an example say the thunder clap starts off at 40,000 Hz and goes down to 10,000 Hz during the rumble.
Humans wouldn't be able to hear the start of the clap (tune) but dogs would? (Again ?)

The speed of sound is independent of the frequency so the dogs could not hear it first.

pedigree 6

Gaoth Laidir wrote: »

The speed of sound is independent of the frequency so the dogs could not hear it first.

Maybe I'm not explaining myself properly.
Say someone playing a brass instrument and they start off in a high pitched note and go to a lower pitched note.
What do you hear?
You hear the first note played first.

Actually when you think of it high pitched sound bounces off things while low pitched is absorbed.

Listen I'm not going to argue.
Just offering a hypothesis.

pad199207

Anyone know where you can access the lighting strike count for the US for today? There's have been an incredible amount of lightning activity across the gulf states today!

vicwatson

pad199207 wrote: »

Anyone know where you can access the lighting strike count for the US for today? There's have been an incredible amount of lightning activity across the gulf states today!

This any good ?

http://en.blitzortung.org/live_lightning_maps.php?map=30

Iancar29

http://en.sat24.com/HD/en/eu/visual

Some convection taking place in the midlands at present moving NE. The odd sferic is possible id say.

Bsal

Looks nice from space

Meteorite58

Monday night / Tuesday chance of Thunder and hail . Met Eireann saying especially in the E on Tues.

Meteorite58

Day 2 Convective Outlook
VALID 06:00 UTC Mon 24 Apr 2017 - 05:59 UTC Tue 25 Apr 2017

ISSUED 17:37 UTC Sun 23 Apr 2017

ISSUED BY: Dan

On Monday, a sharpening upper trough will slide slowly SE-wards across the British Isles, driving a cold front southwards and eventually introducing an Arctic airmass overnight into Tuesday. Given strong flow aloft along the cold front, some elements of line convection will be possible, albeit in a rather messy fashion and generally lacking in any sufficient depth to be concerned over lightning potential.

However, ahead of the cold front, hints of surface troughing will likely help the development of some low-level convergence on Monday afternoon / early evening, sufficient to generate a few moderately-heavy showers over S/SE England. Overall convective depth is likely to be too shallow for lightning activity, but have issued a low-end LOW threat level to highlight the area with some very marginal potential for isolated lightning activity.

Farther north, more significant instability will develop through the evening and overnight as the upper trough and associated cold airmass drives southwards. During the night hours, the most intense convection will be found over seas and hence affecting windward coasts, and here the lightning potential will be greatest (albeit still considered a LOW threat level in any given location). Small hail and gusty winds will be possible with some of these wintry showers (along with the associated risk of snow accumulations, especially on high ground). A few cold air funnels (or brief tornado/waterspout) will also be possible.

Meteorite58

I wonder will there be a bit of activity along the N and NW coasts later tonight ?

Oscar Bravo

Lightning just to the north of Castlebar town about an hour ago in a heavy shower of hail/sleet. temperature dropped to 1 degree in the shower.

DominoDub

Pea sized hail just now in Dublin 2 ...maybe even a rumble

pad199207

Thunder here in D20

Jpmarn

Heard a clap of thunder near Limerick city.

Meteorite58

No thunder observed here near Tralee but some impressive cloudscapes with good sunshine all day. Not much precipitation in Tralee , few big drops and side swiped by a hail shower . Outside Tralee I got 4.0mm in the gauge. Good few sferics around the country .

Big hail/ rain shower here atm.

Tralee at 15.30

Comhrá

Meteorite58, what website did you source the nice satellite pic of Ireland from, please?

Meteorite58

Meteorite58, what website did you source the nice satellite pic of Ireland from, please?

Here you go Comhra, great site .

https://worldview.earthdata.nasa.gov/

Comhrá

Thanks Meteorite58, great site alright, just checking it out now.

Meteorite58

Slight possibility of a couple of rumbles tomorrow I would think.

Meteorite58

http://www.convectiveweather.co.uk/forecast.php?date=2017-04-30



Day 2 Convective Outlook
VALID 06:00 UTC Sun 30 Apr 2017 - 05:59 UTC Mon 01 May 2017

ISSUED 21:31 UTC Sat 29 Apr 2017

ISSUED BY: Dan

On Sunday, medium level instability will be present close to the cold front as a narrow plume of high ThetaW advects northwards from Iberia on the forward side of the disrupting trough. The exact interaction between this trough disruption and surface features remains a little uncertain, but it is plausible some embedded elevated convection may occur close to the front, perhaps deep enough to produce some sporadic lightning.


On the rear-side of the cold front, surface troughing will lead to low-level wind convergence over SW England and SW Ireland, which may serve the focus for some isolated surface-based convection to occur on Sunday afternoon and early evening. Too much uncertainty exists over this potential and subsequent coverage, but given some reasonable DLS there may be scope to upgrade either of these areas to SLGT should confidence/coverage increase.