Storm Francis - 24th/25th August 2020

Meteorite58

Thought it might be timely to begin a thread about the next system approaching later Monday 24th into Tues 25th. Not sure if it will be giving a storm name , it is up to UK Met to call this one and it might just fall under the criteria for naming it.
Anyway we can keep an eye on it and see how it progresses.

ECM, UKMO, ARPEGE and GFS all quite well grouped in track and strength at this early stage but there is obviously variances in where the strongest winds will be. Models in the last couple of runs show the track of the system more crossing central Ireland keeping the strongest winds in the SW and along Southern coasts. The further S the system the more it will take the strongest winds offshore and like wise the further N it tracks the stronger the winds inland. It may be that a large area of Ireland does not get any notable winds from this.

Rain wise looks heavy especially in the W and along S and SE coasts.

Los of instability could lead to some vigorous thunderstorms from early morning moving up through the country from the SW I reckon.

Just to Note that ICON has given the system a very flabby look on its latest run and not showing any significant winds, big departure from the last run and this might be an outlier.

The GFS is probably a fair representation of the models in general for the moment anyway if perhaps a bit stronger.

Gaoth Laidir

The 12Z analysis just now shows where Tuesday's system is originating. An area of high theta-e, under an increasing jetstream, which will reach around 270 kph at 200 hPa tomorrow. A lot of scope for changes in how the deepening surface low phases with this jet later tomorrow and during Monday, so no point looking at specifics for now, but at least it's more of a typical baroclinic storm, rather than of post-tropical origin.

sdanseo

Looks awesome in terms of its symmetry and proportions in size to Ireland, giving it a tropical-like appearance and structure. Parts of the country would experience a few different types of weather in quick succession and some would see the eye pass over with almost no weather to speak of in the lull, more similar to a tropical storm than a European windstorm with their ill defined centres.

Impressive on a map and dramatic looking for the likes of IWC but in terms of windspeed a low-grade tropical storm for now.

Tropical systems of a lower apparent strength can still pack a punch compared to what we're used to, (others will be surely able to expand on that and the reasons why I hope?) so will be a very interesting one to follow nonetheless.

Oneiric 3

Fairly reasonable agreement on the 06z En suite that the south would be at the higher risk of seeing the strongest of any winds from this system, but early days yet.

sdanseo

I keep being stuck by the more compact / cyclonic appearance of this and also Ellen. Just more visually impressive.

12Z ECM not convinced of anything more than perhaps 100km/h gusts.
UKMO has the core of the wind well out to sea, albeit slightly stronger.
6Z GFS showing a stronger system.

All looks benign in comparison to early Ellen charts but also slower moving with larger areas of the strongest winds perhaps lasting 6 to 8 hrs in places.

Meteorite58

Again the GFS ECM and ARPEGE sre fairly well grouped. UKMO and ICON taking a lower track through the SW to the SE and hence keeping the stronger winds off shore.



I think the main factor showing up atm is the rainfall amounts, can see the models showing large amounts falling in 24 hrs, between 20 and 35m widespread and up to 50 mm in places possible. I wouldn't take the areas being shown as definite's, just an indication of possible heavy rain leading to spot flooding or more localised flooding.

Still early days and has been discussed, modelling currently proving a bit more tricky as less data available due to less marine and air traffic.

Graces7

Thank you. Just read re next Tuesday and already covered!

Gaoth Laidir

The UKMO have it as a fast-moving system, with its centre passing right over the centre of Ireland. It won't just affect Ireland, however, so it will be a race to see which country names it first. Could be us, the UK or Netherlands, but in any case it would be Francis.

Gaoth Laidir

Analysis at 7 am. The low is not developing as quickly as forecast this time yesterday. Still just a frontal wave at around 42N 45W.



Forecast yesterday

JanuarySnowstor

Precipitation looks very heavy especially for Western and Northwestern areas.
Not so sure about the wind, looks like yellow levels for much of the country with orange levels in Southern coastal parts.
Certainly one to keep an eye on

Gaoth Laidir

Yes, look at the Harmonie

https://twitter.com/MetEireann/status/1297407930401263616?s=19

JackieChang

Wind's picking up now.

JanuarySnowstor

JMA looking quite potent this morning
Only a matter of time before this one is named.
Yellow rainfall warning most probable!
An orange wind warning is also possible though orange seems to be the max for this one

JanuarySnowstor

http://www.meteociel.fr/modeles/jma/runs/2020082306/J48-21.GIF?23-6

Latest 06z Jma nudging it further North
Severe enough so soon after Ellen with a storm force gradient in the southwest

Meteorite58

Looking quite windy now for early Tuesday across the southern half of the country and more so in the SW and S coasts. All areas look to be a bit windy at some stage, parts of the Northern half of the country will experience calm conditions as the center of the Low passes over and turn windy after. Very heavy rainfall and possibly thundery as the initial fronts go through. ECM, ARPEGE, EURO 4 on a slightly more Northerly track than GFS, ICON but only just.

Would tend to side with ARPEGE for the moment as looking like the probable winds that we could get and an idea of rainfall accumulations. A bit further S will reduce the winds a bit.

igCorcaigh

Yellow wind and rain warnings issued.

Silver-Tiger

Earlier than usual for these? Would they just be too get people's attention with the possibility that upgrades may come?

igCorcaigh

Silver-Tiger wrote: »

Earlier than usual for these? Would they just be too get people's attention with the possibility that upgrades may come?

Sufficient level of confidence in yellow conditions? Might upgrade to orange.

endainoz

Silver-Tiger wrote: »

Earlier than usual for these? Would they just be too get people's attention with the possibility that upgrades may come?

Possibly, bit I'd be more afraid this won't be needed at all as it will be seen as not as powerful as the last one. Considering the atrocious amount of rain forecast combined with what's fallen already, many trees could be under pressure.

brevity

My two days “holidays” in Killarney should be fun...

TTLF

going to Galway during this, I'm actually pretty excited to see what happens. Fun times ahead.

Gaoth Laidir

12Z analysis, showing the 1011-hPa low around half way between New Foundland and the Azores. It's currently underneath the cloud head of a 270-kph jet.

Oscar Bravo

Latest Met Eireann warnings

Status Yellow - Wind warning for Munster and Wexford

It will become very windy on Tuesday as strong southwest winds veer westerly with widespread mean speeds between 50 and 65km/h and gusts between 90 and 110km/h, higher in coastal areas.

Valid: 06:00 Tuesday 25/08/2020 to 19:00 Tuesday

Status Yellow - Rainfall warning for Connacht, Donegal, Cork, Kerry and Waterford

Intense rainfall is expected at times Monday night and on Tuesday. Falls of 30 to 50mm are expected with surface flooding.

This rainfall will further elevate river levels and may result in river flooding also.

Valid: 00:00 Tuesday 25/08/2020 to 23:59 Tuesday 25/08/2020

JanuarySnowstor

https://modeles.meteociel.fr/modeles/icon/gruns/2020082312/icon-0-45.png?23-12

Icon is first out the blocks this evening and it keeps the low pressure quite flabby. No wind event here but of course it got Ellen wrong also!

JanuarySnowstor

https://modeles.meteociel.fr/modeles/gfs/runs/2020082312/gfs-0-48.png?12
12z Gfs, slightly tighter gradient across the South!
Orange territory for wind!

watlantic

Certainly an interesting Monday night/Tuesday morning ahead. The rain and T-storm potential looks quite dramatic on the ECMWF model run, particularly for the west. GFS has the central pressure a bit lower and the storm's arrival a bit earlier, but overall there's good model consensus. Bft 8 to 9 (possibly stronger gusts locally)winds seem less of a threat this time, but significant amounts of precipitation could be dumped in places in a relatively short time frame.

Gaoth Laidir

The latest UKMO fax for 12Z tomorrow has the low 4 hPa higher than the 00Z forecast run had it, 998 vs 994 hPa. Positionwise a hair further east.

Latest forecast cycle



00Z forecast cycle

JanuarySnowstor

http://modeles.meteociel.fr/modeles/gem/runs/2020082312/gem-0-48.png?12
Gem similar to gfs, tight gradient across the South!

sdanseo

GFS much of the same really. Wind field a bit larger and further south. No orange level wind over land.

Fine margins though, 25km/h higher is red territory which of course is more a failing of the absolutely ridiculous warning criteria than anything meaningful.

Bear in mind at this range in advance of Ellen one model (ECM) was calling for 202km/h in around the same location.

Rainfall though is a different story. Much of Galway and Mayo well into orange warning territory >50mm/24h.

JanuarySnowstor

http://www.meteociel.fr/modeles/jma/runs/2020082312/J42-21.GIF?23-12
This evenings Jma not for off a full blown storm.
Nudges the system further North than the others bringing more of the country into orange category.
Met Eireann will likely name this system later this evening

Tazio

JanuarySnowstor wrote: »

http://modeles.meteociel.fr/modeles/gem/runs/2020082312/gem-0-48.png?12
Gem similar to gfs, tight gradient across the South!

Yea saw that too..it's been hinting on and off for a while at another Kerry / Cork storm again . Great

sdanseo

12z ECM out in the next hour or so. MÉ more likely to take any naming decisions based on that and Harmonie.

JanuarySnowstor

https://www.meteociel.fr/modeles/ecmwf/runs/2020082312/ECM1-48.GIF?23-0

Ecm says hello storm Francis!!

sdanseo

On the contrary, ECM not convinced yet. But a slight upgrade on its part nonetheless.

I wouldn't like to be the one calling this one. I'd say they probably will, eventually, given all the recent rainfall, wind and the potential that the ground is sodden and trees will already be weakened as well as in full leaf.

The 146km/h mark can be discounted as it's 3,000ft in the air.
Generally gusts struggling to 110km/h or to a mean of 65km/h over land.
Rainfall 6h/24h also barely just almost at Orange levels. (45-50mm/24h - Orange would be 50mm/24h + )

Oscar Bravo

Update

Status Yellow - Wind warning for Munster, Carlow, Kilkenny and Wexford


It will become very windy on Tuesday as strong southwest winds veer westerly with widespread mean speeds between 50 and 65km/h and gusts between 90 and 110km/h, higher in coastal areas.

Valid: 06:00 Tuesday 25/08/2020 to 19:00 Tuesday 25/08/2020

Issued: 20:19 Sunday 23/08/2020

Gaoth Laidir

Analysis at 18Z has it 1010 hPa at 44N 40W, slightly higher than forecast yesterday. Water vapour image for the same time. The low centre is located just north of that darkest green blob near the centre of the image.





UKMO Fax shows slightly stronger gradient winds along the west and south coasts. The centre will be travelling at around 40 kph so it will be a fairly quick period of maximum winds. Out at the current centre the total precipitable water is 50-55 mm, so plenty to generate those high rainfall totals, especially on southeast-facing upslopes, such as in Kerry, Cork and Wicklow.

Meteorite58

ECM, UKMO and ARPEGE quite tightly grouped, GFS a small bit lower and deeper, ICON higher pressure by far and coming in the furthest S.

So ARPEGE probably a good representation of the first group, been fairly consistent also, HARMONIE coming into view and looks like the highest winds very much a coastal thing. Track similar to UKMO, down to 979 hPa just off the N Kerry coast at 07.00 Tues and 983 hPa at 13.00 as the center is over the East coast.

Marine warning might go Orange and this might cover coastal land areas.

Looks like a high end Yellow warning in the Munster region atm.

Meteorite58

I think it could go to an Orange warning level for rainfall along the SW, S. Going by the ECM looks like they could get over 30 mm in 6 hours . UKMO similar

Was in Killarney today and the lakes are extremely high, even spilling into the car parks at Ross Castle.

Meteorite58

Met Office


Tues 01.00



Tues 13.00



Weds 01.00



Warm moisture laden air mass. DP getting up around 15C

Oneiric 3

Meteorite58 wrote: »

Met Office


Tues 01.00

This does not look to dissimilar to the pattern which brought some record-breaking rainfall totals to the SW back in August 1986. Syran spoke of this event just recently in fact.

Oneiric 3

The EPS (mean of all the ECMWF runs) seems fairly certain now that we are all in for a fair dollop of rain by midnight Tuesday, with the SW in general bearing the brunt:

JanuarySnowstor

https://modeles.meteociel.fr/modeles/gfs/runs/2020082318/gfs-0-42.png?18
Tonight's gfs is upgrading a nudge
Orange territory now for wind South of the centre
If that ain't a storm I dunno what is!

pad199207

Status Yellow - Rainfall warning for Ireland

Met Éireann Weather Warning

Intense rainfall is expected at times Monday night and on Tuesday. Falls of 30 to 50 mm are expected with surface flooding.

This rainfall will further elevate river levels and may result in river flooding also.

Valid: 21:00 Monday 24/08/2020 to 21:00 Tuesday 25/08/2020

Issued: 06:41 Monday 24/08/2020

M.T. Cranium

I certainly agree with everything posted about this event, but just wanted to add that readers in many parts of the country, in particular central Leinster, are going to experience a fairly prolonged interval of light winds due to the shape and trajectory of this low, as it tracks through counties from about Clare to Dublin/Meath, so please don't come on slagging forecasters about the absence of the predicted alert level winds, those are most likely to affect Munster and south Leinster and only late in the event will they start to blow in more moderate intensity across central counties in the wake of the departing storm.

Gaoth Laidir

Latest analysis has it 1002 hPa down 5 hPa iin 5 hkurs and looking like a plate of spaghetti.



Latest forecasts, showing the positioning of the strongest gradients along the south.

Supercell

Flooding rather than wind damage may be the main story here. Cork could be in for bad flooding again, Bray in Wicklow has flooded several times in recent memory too and may be vulnerable again tomorrow into Wednesday. Just two examples that spring to my mind when looking at those fax charts.

sryanbruen

Named Francis by the UK Met now.

Oneiric 3

Supercell wrote: »

Flooding rather than wind damage may be the main story here. Cork could be in for bad flooding again, Bray in Wicklow has flooded several times in recent memory too and may be vulnerable again tomorrow into Wednesday. Just two examples that spring to my mind when looking at those fax charts.

I agree, I think the potential mod to high rainfall totals in parts of the south will be the bigger story from this system.

Graces7

sryanbruen wrote: »

Named Francis by the UK Met now.

Why do they pick such.... friendly names? Ellen! Francis! Gentle names.

Graces7

Graces7 wrote: »

Why do they pick such.... friendly names? Ellen! Francis! Gentle names.

Maybe they should have chosen Frankenstein!

or after tropical diseases like Ebola.

Gaoth Laidir

Met Éireann's Harmonie has been very consistent since yesterday with its rainfall forecast. The big problem is going to be that training rainband lying across the centre of the country tomorrow afternoon and evening. Several hours of 5-10 mm/hr rainfall rates through the midlands and east.

https://twitter.com/MetEireann/status/1297786040464408576?s=20