Cold Spell - Feb 7th to 13th 2021 - Technical Discussion

TheMilkyPirate

Hopefully the GFS has support in the morning

Danno

Nqp15hhu wrote: »

It was <-10c 850hPa here today and we still rose to 2c, so I am not convinced -13c would deliver anything lower than 0c during the day. Unless cloudy

It will be interesting to see what we max out at tomorrow due to the lower minimums.

Ballyhaise only maxed out at -9.4c under this.

Upper air temperatures are not a rule over temperatures lower down.

Nqp15hhu

Danno wrote: »

Ballyhaise only maxed out at -9.4c under this.

Upper air temperatures are not a rule over temperatures lower down.

I understand, I have seen a few of those days here in 2010 and know we had similar highs (-11.3c in Northern Ireland). However, that’s after days of cold pooling.

Cold air here does not usually mix down to the surface immediately, there can also be fairly steep lapse rates with these continental sourced systems. Most are forecasting highs of 1c on Wednesday. (I have witnessed a 2c high with -13/-14 850hPa).

Arduach

Danno wrote: »

I often wonder as we approach mid February (I know today is only the 8th) does a stronger sun, longer day (even though it was cloudy) mean the rule of thumb of adding 8c to the upper temperature goes out the window? Do we have to add 10c?

That Ballyhaise temp was taken around the solstice?

Arduach

Nqp15hhu wrote: »

I understand, I have seen a few of those days here in 2010 and know we had similar highs (-11.3c in Northern Ireland). However, that’s after days of cold pooling.

Cold air here does not usually mix down to the surface immediately, there can also be fairly steep lapse rates with these continental sourced systems. Most are forecasting highs of 1c on Wednesday. (I have witnessed a 2c high with -13/-14 850hPa).

That makes sense.

YanSno

Some models are over cooking the front on Thursday into Friday. ICON precipitation chart looks very light while it fizzle out as it reaches the Midlands, most likely solution. I'm not saying it will not snow but nothing too significant and nowhere near any previous memorable event.

Nqp15hhu

This is the sounding for Wednesday for here. We may get an ice day if it remains cloudy or is windy.

M.T. Cranium

I'm thinking colder air from Scotland will seep in during the period Tuesday night to mid-day Wednesday, but the -3 to -5 is more of a prediction for inland south Ulster than the north coast which would probably stay closer to freezing.

M.T. Cranium

M.T. Cranium wrote: »

I'm thinking colder air from Scotland will seep in during the period Tuesday night to mid-day Wednesday, but the -3 to -5 is more of a prediction for inland south Ulster than the north coast which would probably stay closer to freezing.

I didn't want to say it,but your jan 1982 comment earlier
I've been thinking that for the past few days about tbis

Nqp15hhu

Well today the sub zero air stayed at 250m-300m. Think we would need -14/-15c 850hPa to guarantee an ice day widespread, with a cold airmass that has only just came through.

TTLF

Might be a silly question, but since It's about the Thursday's low and possible snow event I think It's appropriate to ask here, what counties specifically "In the East" would be experiencing possible Orange level? (Kind of doubt red warning just sceptical about it.) Also I'm guessing "North Leinster" spans from Dublin up to Louth incl Meath?

Thanks

lolie

Bbc forecast fairly confident of mider air over ireland during the weekend, be interesting to see if they still think that in the morning forecast.

Villain

Downgrades all round this morning, less snow Thursday into Friday and then milder air wins out for weekend, unusually consistent across the models too!

Could still change but bad morning .

pad199207

Villain wrote: »

Downgrades all round this morning, less snow Thursday into Friday and then milder air wins out for weekend, unusually consistent across the models too!

Could still change but bad morning .

I couldn’t even bring myself to post. Woeful start to the day. Waiting for 12z to give up the ghost but it’s certainly solid across the main models.

DOCARCH

Villain wrote: »

....milder air wins....

It is our 'default'. It usually does win in these situations!

Humberto Salazar

Ah well there's always next winter. Models swift in bringing Atlantic in this morning. No one ever bets long term against it.

Slashermcguirk

Hardly, met Éireann as of an hour ago going for snow until Saturday. Stop posting nonsense

Humberto Salazar wrote: »

Ah well there's always next winter. Models swift in bringing Atlantic in this morning. No one ever bets long term against it.

Villain

Slashermcguirk wrote: »

Hardly, met Éireann as of an hour ago going for snow until Saturday. Stop posting nonsense

The latest models have just updated, expect forecasts to change, it can still change but when UKMO, GFS and ECM all move the same way it would be some change to see them flip back.

Slashermcguirk

For Saturday I would assume it could change alright, as long as there is snow Thursday and Friday I am not bothered about the weekend. I would be surprised if met Éireann would go on Claire Byrne show last night to say big snow unless they were certain about the near forecast like Thursday. Weekend was always going to be a battleground

Villain wrote: »

The latest models have just updated, expect forecasts to change, it can still change but when UKMO, GFS and ECM all move the same way it would be some change to see them flip back.

Zogabomb

Villain wrote: »

The latest models have just updated, expect forecasts to change, it can still change but when UKMO, GFS and ECM all move the same way it would be some change to see them flip back.

That is in regard to the weekend though, Thursday still looks interesting, no?

Snowbiee21

Zogabomb wrote: »

That is in regard to the weekend though, Thursday still looks interesting, no?

No. ECM GFS UKMO say no

Humberto Salazar

Slashermcguirk wrote: »

Hardly, met Éireann as of an hour ago going for snow until Saturday. Stop posting nonsense

It's not going to 'snow until Saturday'. We have a risk of frontal snow for Thursday and Friday yes, and then according to ECM, not me, the mild push gets through during Saturday. I post facts not nonsense. You can dispute the facts if you wish.

Villain

Zogabomb wrote: »

That is in regard to the weekend though, Thursday still looks interesting, no?

Oh still snow widely Thursday and into Friday but amounts also reduced a little.

Zogabomb

Snowbiee21 wrote: »

No. ECM GFS UKMO say no

Not true for Thursday and into Friday for the North and East at least

Slashermcguirk

You are talking nonsense, you said winter over when a lot of snow is due Thursday and Friday. If winter was over the mild would be arriving now. The weekend is far less of a big deal if a lot of people get snow between now and Friday. Just dismissing that is ridiculous

Humberto Salazar wrote: »

It's not going to 'snow until Saturday'. We have a risk of frontal snow for Thursday and Friday yes, and then according to ECM, not me, the mild push gets through during Saturday. I post facts not nonsense. You can dispute the facts if you wish.

pad199207

Given all the erratic behaviour of the models of recent there still is the chance that this could be just a big wobble by the models overnight and may be corrected later today but it’s a smidgen.

Just don’t call it until the 12z come out, can’t stress that enough.

Snowbiee21

Zogabomb wrote: »

Not true for Thursday and into Friday for the North and East at least

In terms of precipitation rates, a definite downgrade

Zogabomb

Snowbiee21 wrote: »

In terms of precipitation rates, a definite downgrade

Maybe so but still interesting. Definite snow potential

Slashermcguirk

Just read your own post, usual negative sensationalist nonsense. “There is always next winter”and.....”models swiftly bring in the Atlantic this morning”’...........Talk about misleading when that is likely on Friday or Saturday.

Humberto Salazar wrote: »

Ah well there's always next winter. Models swift in bringing Atlantic in this morning. No one ever bets long term against it.

KingdomRushed

There is a near total flip if not total flip to milder in the GFS ensembles. I can't see any snow risk post Friday myself now. The scatter is gone. I presume no more scandi highs developing in the set.

Gfs operational is all rain too from Friday night onwards. Thereafter lots of potent rain systems move through leading to likely flooding concerns especially for Munster.

I have to say after the promise of a 2-4 day whiteout it is disappointing. At least we will still see some frontal snow Thursday, but don't snooze on it, it won't be around long