General Model Output Discussion

[ribster]

I am amazed tonight at the number of members that are debating the models from +144 onwards, now I know that the model discussion is to discuss the variation in the models but these charts very rarely verify.

SS2

Clue is in the title though....

[PB22]

18Z GFS sticks to its guns with the easterly theme for next week:

http://www.wzkarten.de/pics/Rtavn1261.html

http://www.wzkarten.de/pics/Rtavn1262.html

[Matty M]

Fairly decent 132hr chart from the GFS

Ultimately such a shame we dont have a deep cold pool to tap into though.

[snowingtequila]

On this run I think some snow would be possible by Monday night in the south east maybe?

http://91.121.94.83/modeles/gfs/run/gfs-0-120.png?18

[Grimsby Snow Lover]

Don't often comment on here due to my lack of knowledge but could someone tell me whether this potential easterly would deliver snow to coastal regions as Sundays easterly gave us heavy rain here. The 528 dam seems to be over us which is surely a good sign if this actually happened. Would love a bit of help thanks.

[igloo]

18Z GFS sticks to its guns with the easterly theme for next week:

http://www.wzkarten..../Rtavn1261.html

http://www.wzkarten..../Rtavn1262.html

yes just by the skin of its teeth everything looks very slightly further east i would not be surprised if future runs follow the same line as the ECM after all that tends to happen with this model

[grab my graupel]

Fairly decent 132hr chart from the GFS

Ultimately such a shame we dont have a deep cold pool to tap into though.

Would we need a deep cold pool, though, Matty? I'd have thought the continent would cool quite rapidly once the block was established

[Cloud 10]

ecm12z gfs18z

GFS and ECM go head to head at +144hrs,which one will be closer to the mark?

[cooling climate]

I do not know if this has been posted yet. This snippet is from Bret Anderson over on Accuweather.

Tuesday, January 12, 2010 3:11 PMGreat News for Forecasters of Winter Storms and UpdateNow this is something that can really be helpful to weather forecasters, and I am happy to forward this new release from the National Oceanic and Atmospheric Administration (NOAA). Due to the shear size of the Pacific, there has been clearly a lack of real data that gets loaded into the computer models. This project should certainly help in reducing some of the flip-flopping of models for storms several days out and of course improve the overall accuracy as we get some real, accurate atmospheric readings of storms out in the Pacific that will eventually push across the United States and Canada. Nice to see!

NOAA Dispatches High-Tech Research Plane to Improve Winter Storm Forecasts

NOAA’s Gulfstream IV aircraft, known for investigating Atlantic hurricanes, will begin flying over the North Pacific Ocean to fill gaps in atmospheric observations, which will enhance forecasts of winter storms for the entire North American continent through improved computer modeling.

The highly specialized twin turbofan jet will be stationed at Yokota Air Force Base in Japan through February before repositioning to Honolulu in March. From these locations, the aircraft will be tasked by the National Centers for Environmental Prediction — a division of NOAA’s National Weather Service — to fly into data sparse regions to collect information such as wind speed and direction, pressure, temperature and humidity. This data will be sent via satellite to global operational weather forecasting centers — and fed into sophisticated computer forecast models.<BR itxtvisited="1"><BR itxtvisited="1">“These flights will help us better observe and understand the current state of the atmosphere over the Pacific, where most of North America’s weather originates, in order to better predict future conditions across the U.S. and Canada three to six days in advance,” said Louis Uccellini, Ph.D., director of the National Centers for Environmental Prediction in Camp Springs, Md.<BR itxtvisited="1"><BR itxtvisited="1">These computer model improvements will play an essential role in meteorological support for the Winter Olympics in Vancouver in addition to more precise precipitation forecasts along the U.S. West Coast and points farther east.

NOAA incorporated the Japan-based missions into its annual Winter Storms Reconnaissance program in early 2009 -- flying 332 flight hours and logging miles equivalent to circling the Earth five times. Prior to 2009, missions were flown from Alaska, Hawaii and the U.S. West Coast. By expanding the reach across the International Date Line to Japan, NOAA is essentially pushing farther upstream to observe areas of interest with greater lead times.

These missions showed significant positive impact to global numerical weather prediction models, increasing both accuracy and lead times for high-impact weather events. For example, model forecasts of precipitation amounts improved, on average, 10 to 15 percent.

------------------<BR itxtvisited="1">

[Matty M]

I would take this 18z GFS

[Tom D]

Fairly decent 132hr chart from the GFS

Ultimately such a shame we dont have a deep cold pool to tap into though.

I remember reading here a couple of days ago that despite the uppers not necessarily showing 'deep cold' as you put it, remember that continental Europe is frigid at the surface, so any airflow originating from that direction will also be very cold.

Re ECM vs GFS - does anyone have a link to the ensembles for the ECM? (London or Holland).

Edited January 13, 2010 by Tommyd1258

[Matty M]

Would we need a deep cold pool, though, Matty? I'd have thought the continent would cool quite rapidly once the block was established

Probably not as we have very dry cold surface cold and it would develop but it would be nice to have the full lot!

[Guest North Sea Snow Convection]

Excellent GFS 18z - and keeps the continuity going. Love the way that little low undercuts ESE through northern france and helps the cold keep backing further and further west.

As suggested earlier, the ECM operational was on the warm side - so the easterly is not off the agenda by any means. Hopefully 'as you were' once again in the morning

Edited January 13, 2010 by North Sea Snow Convection

[Spurry]

From (limited) experience i know the 18z(pub run) can be a bit unconventional at times , but if this one comes off then next tuesday /wed should be a snow/coldfest (why is there not a smilie for going on knees and praying)

Edited January 13, 2010 by Spurry

[Tom Montalbano]

That 18z GFS run has left me exhausted. I'm at about t228 now and it was like watching a "Rocky" film. Atlantic lows and Siberian high trading blows, with the Siberian High gaining the upper hand until they both seem exhausted and on the ropes but neither of them can land the knock-out punch!

Regards,

Tom.

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

The -10 uppers could be back pretty soon:

[Cloud 10]

That 18z GFS run has left me exhausted. I'm at about t228 now and it was like watching a "Rocky" film. Atlantic lows and Siberian high trading blows, with the Siberian High gaining the upper hand until they both seem exhausted and on the ropes but neither of them can land the knock-out punch!

Regards,

Tom.

Its good to know the 18z hasn't lost its touch.

All eyes on the 120 fax.

[Tom Montalbano]

Ladies and Gentleman, a unanimous decision on points, the still undefeated Northern Hemisphere pressure champion, in the Red Corner,

"The Siberian High". (For showing more aggression for the the majority of the run). I'll get my coat and go and lie down in a dark room for half an hour!

Regards,

Tom.

[Weather-history]

Saturday 1pm UKMO temps

Not exactly mild away from the SW

[jam]

Saturday 1pm UKMO temps

Not exactly mild away from the SW

Not bad for the ' Big Thaw'... bet that hasnt been mentioned quite so much today on the 'meeja'

[casparjack]

Saturday 1pm UKMO temps

http://www.meteociel...2-580.GIF?13-18

Not exactly mild away from the SW

What's also very apparent is the large swathe of -5/-6c to the East, not far away...

[Cloud 10]

Tonight's +120 fax.meteociel.fr - modèle UKMO pour la France, resolution 1.25 degré

A fair bit different to the 18z! but not without promise.

[Thundery wintry showers]

Don't often comment on here due to my lack of knowledge but could someone tell me whether this potential easterly would deliver snow to coastal regions as Sundays easterly gave us heavy rain here. The 528 dam seems to be over us which is surely a good sign if this actually happened. Would love a bit of help thanks.

Would we need a deep cold pool, though, Matty? I'd have thought the continent would cool quite rapidly once the block was established

You don't need an especially deep cold pool to give sunshine and snow showers off an easterly. 850hPa values near -10C and thicknesses of around 522 dam or below tend to suffice, and the cold pool we'd be tapping into easily fulfils both of those criteria. Only eastern coastal districts may see marginal temperatures- but even those areas should get cold enough if the easterly can persist for upwards of a couple of days. It's more a question of whether this easterly will come off or not, rather than whether it will be cold enough.

The main reason why we traditionally see a lot of dry cloudy easterlies is because the air often ends up sourced from southern Europe and thus stable and not especially cold. This does not look likely from the current setup- the more likely way for the easterly to go the "way of the pear" would be for it to be situated too far east leaving Britain in a no-man's land, which is still a possibility, about 30% for now.

[Avain]

Hmm, the other day when the GFS 18z "pub run" (what does that mean? the forecast team went to the pub and got plastered?) came out and showed a warmer trend many of the cold lovers were decrying it and saying don't take any notice of the pub run, it's usually no good etc, but tonight, because it shows a colder aspect, it's suddenly got more respect than a hoodie with a tank? A certain lack of objectivity with the assessment of the models perhaps?

Edited January 13, 2010 by Avain

[phil nw.]

Ladies and Gentleman, a unanimous decision on points, the still undefeated Northern Hemisphere pressure champion, in the Red Corner,

"The Siberian High". (For showing more aggression for the the majority of the run). I'll get my coat and go and lie down in a dark room for half an hour!

Regards,

Tom.

Yes it`s very much like a fight as in Harry Hill`s show(which is better?).

Seriously though Tom this could run and run with less cold interludes,as per the weekend, and cold spells in between.

That Siberian block is massive but the vortex is looking stronger than it`s been all Winter up to now and periously close to it`s nest.

http://www.wetterzentrale.de/pics/Rhavn1201.gif

We are at the end of the Siberian line and can never be sure at this stage how it will pan out.