Model Outlook Thread: January 2010

nacho libre

i'll see your chart and raise you this one:P
a chart simliar to the above is what i'd like to see sometime this February

it must have been good to be alive that day if you were a snow fan

polar low heaven

jambofc

look's like the Atlantic is just to strong at the mo,just keeps pushing those loverly easterlys away every time they try to come in.

maquiladora

Maybe a few light sleet/snow showers on the east coast next Monday/Tuesday based on the 06Z GFS.

maquiladora

maquiladora wrote: »

Maybe a few light sleet/snow showers on the east coast next Monday/Tuesday based on the 06Z GFS.

It has no significant support from other models especially the ECM so that "maybe" is a 1% maybe.
No holding of breaths as defibrillators are scarce

JanuarySnowstor

It looks like ice days are back next week!

kleefarr

Kilkenny City outskirts..

Getting chilly here now..

Temperature: -0.5 °C
Dew Point: -0.8 °C

Clear skies. Frost forming.

patneve

GFS 18Z showing a potent northerly starting next Thursday. Really ridiculous, the forecasting models are/have been all over the place in the past few days. Very interesting times:D

typhooner

GFS has done it's usual 18z wandering around with a mega cold northerly at +216...

http://www.wzkarten3.de/pics/Rtavn2162.png

Su Campu

Yes 1990 certainly was a windy one. Here are the daily summaries, click on the + to see more for each day. Look at Jan 25th at Roches Point!!! :eek:

Roches Point - Jan Feb
Belmullet - Jan Feb
Malin Head - Jan Feb
Valentia - Jan Feb


Roches Point
Extender Data January 25, 1990
Mean temperature:7.3 ºC
Mean dew point:4.7 ºC
Maximum temperature:11.5 ºC
Minimum temperature:3.5 ºC
Mean sea level pressure:979.7 mb
Mean station pressure:--
Mean humidity:84 %
Mean visibility:15.1 Km
Mean wind speed:53.2 Km/h
Maximum sustained wind speed:107.2 Km/h (66.6mph - Hurricane Force) :eek:
Maximum wind gust:159.5 Km/h (99mph) :eek:
Precipitation amount:17.02 mm
Occurrences:Rain or Drizzle

Joe Public

Some of these threads are changing like the weather so the only conclusion I can come to is that the outlook is changeable.

M.T. Cranium

If the flow stays as zonal as the ECM advertises, the cold spell can't really take hold, but strong SW to W winds are quite possible around the end of January given a high energy peak on the 30th. If the flow buckles and allows in a strong northerly, then I would look for this to become a strong NW wind event. So either way, the major models are setting up for strong winds to end the month. The main question to be resolved is direction and whether it becomes cold enough for snow to enter the circulation behind the storm.

It's rare to see such a complete contrast between the two models, they often differ on details but today we're being offered two almost opposite resolutions as early as day five. Hope they agree by midnight because I have to try to pick out a forecast from this mess by 0500.

WolfeIRE

The models seem to indicate polar air moving south in the early part or middle of next week. I have never seen such movement on the models.

nacho libre

M.T. Cranium wrote: »

If the flow stays as zonal as the ECM advertises, the cold spell can't really take hold, but strong SW to W winds are quite possible around the end of January given a high energy peak on the 30th. If the flow buckles and allows in a strong northerly, then I would look for this to become a strong NW wind event. So either way, the major models are setting up for strong winds to end the month. The main question to be resolved is direction and whether it becomes cold enough for snow to enter the circulation behind the storm.

It's rare to see such a complete contrast between the two models, they often differ on details but today we're being offered two almost opposite resolutions as early as day five. Hope they agree by midnight because I have to try to pick out a forecast from this mess by 0500.

i bet the gfs will do what it usually does in these situations and back the ecm evolution at the last minute;)

WolfeIRE

WolfeIRE wrote: »

I have never seen such movement on the models.

you can't say that with much authority lol as you haven't been looking at them long :pac:

I can recall several actual situations in recent decades where the continental cold gets deflected up the north sea at the border of the atlantic influence.
The border will always be somewhere and sometimes we are lucky and the border goes well west of Ireland.

Despite what you might read on two or nw,models differing widely outside 48hrs in the face of a continental wide cold block isn't unusual.

darkman2

Don't panic people! The weather can now resume....


Nothing spectacular for the next 7 days. Cold, Briefly Milder midweek next week then Colder again over the next weekend. Nighttime frosts return from tonight. Daytime temperatures generally 3 - 6C. Mostly dry. Some fog at times.

Short and sweet:)

nacho libre

seeing as the russian high is not going to extend its influence over us i wish the cold to the east would completely move away now as it's just getting in the way of a proper wintry outbreak. it's completely pointless having dry and cool days and cold nights.

So i hope M.T. Cranium's idea of a storm(or at least a strong wind event) does come at the end of month followed by potent polar maritime air or a direct feed of Arctic air. such a setup will be brief, but at least we have a shot at some heavy wintry showers and if we are lucky a polar low may develop to bring widespread snowfall across the country.

Not

Seen a snow plough on the M50 this evening. Maybe someone knows something we don't, or it's just arrived two weeks too late..

ch750536

Not wrote: »

Seen a snow plough on the M50 this evening. Maybe someone knows something we don't, or it's just arrived two weeks too late..

Was it moving?

Not

ch750536 wrote: »

Was it moving?

About 80km/h

Snowaddict

There are quite marked differences in NWP Guidance, even out to Day 5 at the moment.

However, towards Day 7 in particular, there is general broadscale agremment amongst NWP Guidance tonight. Out to Day 10 - Day 14, the overall trend would seem to favour a Mid Latitude Block, centred to the West/Northwest of Ireland, in the High North Atlantic. Present indications do not suggest a firm Retrogression signal to Greenland, because of residual energy remaining over Greenland itself.

This is indicated nicely by tonight's CPC Prognostic Medium Term Outlook:

CPC Prognostic Chart - Medium Term Outlook - 500mb Level

http://www.cpc.noaa.gov/products/predictions/814day/814day.03.gif

Again, I am not sure as to what effects, we will see at the tropospheric level from the latest warming at the 30mb Level, 90N, but I certainly do expect to see a strong signal for blocking (Location Very Uncertain) during the latter period of this month & into February, from the residual effects of a displaced and generally unorganised Polar Vortex but also from the effects of the latest warming. Full effects, if they are to occur, will not be seen until about Day 15 - Day 20 from the 25/26th of January.

30mb Temperature



Latest Medium Term ECMWF Ensembles for De Bilt, Holland, suggest a Polar Northerly flow, directly off the North Sea into Holland. This reinforces the concept of a semi-retrogressive block centred to the West/Northwest of Ireland, with a strong Northerly flow into Europe. A weak, perhaps moderate Northwesterly to Northerly flow may also develop across Ireland during this period, depending on how far Northwestwards the block is to ridge. There is a low chance at the moment, about 20%, of a subsequent Northeasterly flow developing in the far medium term during early February, with troughing over the continent. Such a trend is indicated on tonight's ECMWF 12Z Control evolution.

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

NAO & AO

Generally trending neutral to slightly negative into the medium term, the AO suggesting a more marked fall in value later towards Day 10 onwards, indicative of a potential block strengthening over Greenland / to the far Northwest.

Summary

In summary then, pressure rising over the medium term, with generally settled conditions developing across the country. Temperatures perhaps cool overall at first, but with an amount of Atlantic influence still trapped within the general airflow. Quite possibly falling into the cold or rather cold category by Day 7, with somewhat clearer air filtering across the country & being of a somewhat drier nature. Later, around Day 7 & towards Day 10, there is the potential for a more marked Northerly/Northwesterly/Northeasterly airflow across the country, with even sharper frosts.

The general Jet Profile at the moment is very similar to that of the profile at Christmas 2008. However, the 30mb temperature is becoming increasingly supportive of High Latitude Blocking later in the period.

Blocking will persist for some time, the question relates to it's exact location & as to how this will influence us in terms of any renewed cold outbreak. Overall, the outlook is far from clear cut but Background elements give about 55% weighting in favour of at least some form of renewed cold between now & Day 14.

Let's see how it pans out.

SA

Deep Easterly

Snowaddict wrote: »

There are quite marked differences in NWP Guidance, even out to Day 5 at the moment.

However, towards Day 7 in particular, there is general broadscale agremment amongst NWP Guidance tonight. Out to Day 10 - Day 14, the overall trend would seem to favour a Mid Latitude Block, centred to the West/Northwest of Ireland, in the High North Atlantic. Present indications do not suggest a firm Retrogression signal to Greenland, because of residual energy remaining over Greenland itself.

SA

Great summary as usual SA. Unfortunately, there does seem to be a trend towards a slow moving mid atlantic block over the last few runs; the result which will be more non-descript rubbish for the foreseeable. A high in that position will probably mean a lot of cloud overall, particularly for the west and north, with drizzle at times. Could be some decent sunny breaks, particularly further south and east, but temps swings will never be a feature. Neither mild nor cold. Just boring. January is usually the most active weather month of the year weatherwise, but not so this time. Hopefully Feb/March will bring something more violent and vigorous.

jambofc

charts look as exciting as watching francis wilson telling the weather,as said above jan usually a exciting month weather wise but not this year.
i don't really have much hope of the easterly becoming established again,fingers crossed Feb and march might fulfil our appetite for snowy days

I would agree with SA above.
Theres a non descript week coming up.
After that if we can pull a northeasterly out of a northerly we're in business.

Remember ground conditions are still very cold despite recent rain and milder air temps.
The hills near me still have snow drifts in the ditches and on the road edges from the snow 2 weeks ago.
There are the remains of the large 7ft drifts up at 900ft for instance that are still rock solid with 2 ft depth remaining.They're big enough that I can even see them from here at 6 miles distance as the crow flies

Essentially with cold frosty night time conditions,I don't see the ground warming up so it will be a case if more snow comes that it will settle easily.

Su Campu

Here's a 30hPa timelapse since the recent SSW event, showing the regeneration of the strong polar vortex. It remains to be seen what effect, if any, an Atlantic block will have. The probability is minimal, therefore we can also basically rule out the chances of a prolonged period like earlier this month.

darkman2

Im not expecting a long, sustained, cold period as the teleconnections don't fit that scenario for the moment. That's not to say a very cold period will not occur though it will probrably be very temporary. The UKMO this evening is going for a North, Northeasterly toward the end of next week but it looks to be a 48hr thing with High Pressure to the West toppling the flow.

Regarding the above UKMO-I watch the BBC news 24 forecasts a lot.
Yesterday they were emphasizing the cold coming in from the Northeast and spreading SW as the low the precip of which now is still affecting scotland slips into France.

Today completely different.
Totally totally different in just 12hrs...

Rain spreading in from the west as the mild wins over the cold were the words used.
The graphics with the blue with the word cold moving in on the back end of the current low and fronts completely ditched.


Thats a perfect example of how the 2nd largest forecasting service in the world [in my opinion] can't even call weather even 12hrs ahead at times now properly with all the super computer tools and human experience they have.

As for any cold that does come [and it will,it is only january after all]...theres nothing wrong with your typical 4 or 5 day spell of cold aka a quick cold snap.
The problem is for Dublin and the East anyway,that if you warm up the near continent ,you'llnueter a 4 day snap as it just won't have the time to get here properly before the atlantic whisks it away again.It would end up being another hill snow event.

Thats the danger.

A northwestesterly heh...thats a donegal and owenc thing unless you live in Malin head where you'll have cold rain [or Belmullet].

darkman2

Deleted User wrote: »

Regarding the above UKMO-I watch the BBC news 24 forecasts a lot.
Yesterday they were emphasizing the cold coming in from the Northeast and spreading SW as the low the precip of which now is still affecting scotland slips into France.

Today completely different.
Totally totally different in just 12hrs...

Im not supprised. There has been very little consistency between all the models and post 96hrs they all fly off on different tangents. It's been quite bad this winter almost to the point where at times you just cannot make a forcast with much credibility beyond a couple of days. We are not talking about long range - the differences just 3 days in advance have been rediculous at times.

Snowaddict

Another rather uninteresting 12Z GFS Operational evolution, although it must be stated that it has come some way towards the general Euro (ECMWF/UKMO) evolution in the past 24 Hours..

There is indeed a vast amount of uncertainty over the coming days with regard to the general pattern.

It's also interesting to note that the latest NWP Verification Stats suggest that ECMWF & UKMO are once again ahead of other Guidance to Day 5 & Day 6 in terms of accuracy.

I think that the latest 12Z UKMO Evolution is very interesting, trending quite a way towards last night's ECMWF Operational Evolution. Once the segment of the Polar Vortex is advected into Scandinavia later during the coming week in the form of a Northerly flow, there is the potential for secondary cold troughing to develop, with the potential for Westward/Southwestward Advection of relatively deep cold air.



In addition, the latest 12Z UKMO Evolution has another area of Broad HP off the Eastern US Seaboard & Canadian Maritimes at T+144, progressing North/Northwestwards. In addition, at this timeframe, the main block has also ridged into southern Greenland to an extent, with marked WAA up the Western side of Greenland. Another interesting feature is the 1050MB high centred near the Pole at T+144, that could very well bode well for a -AO signal later in the period.

The outlook is very uncertain but that's a very positive UKMO 12Z Operational Run in my opinion & correlates nicely with at least some of the background signals.

However, there is not overwhelming support for a sustained cold or even severe cold outbreak at this time.

Notably, the 30mb Temperature has broken the long term average line on the latest update.

SA

Snowaddict

Today's ECMWF 12Z Operational Evolution has a slow moving, semi-retrogressive Block out to T+144, with at least some height rises over Greenland out to T+144..

If it were to verify then conditions would be turning increasingly colder from a little after midweek next week, with even colder conditions at T+144, along with Northeasterly winds across the country and pressure falling 1010MB & 1007MB. In such a flow, moderate to severe overnight frosts would develop with the threat of wintry showers in Eastern & Northern areas.



This is somewhat even more potent than indicated on the overnight ECMWF 00Z Evolution, however the longevity of any such incursion is very uncertain due to the broadscale pattern in the Northern Hemisphere.

SA

nacho libre

a potent north westerly next weekend with sleet and snow showers by night will do me:D

looking at the models long term anyone hoping for sustained cold can forget it. we were were spoiled with what happened in the so-called "big freeze". It'll likely never happen again for years. So it's back to the more normal routine of four or five days of cold from a potent arctic feed of air, if we're lucky, though it's more likely that we'll get a two day north westerly airflow before the usual atlantic ridge moves in on the third day.