Robbie Garrett
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Posts posted by Robbie Garrett
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Big difference between last November and this November for us is quite clear.
Last Year
- Steeper Temperature Gradient between the Azores and the Atlantic
- Vortex Structure
This Year
- No structure in vortex
- Disrupted jetstream
Looking at the GFS 06z you can quite clearly see some significant changes in the vortex that appears to be getting stronger in 192hrs, to significantly weakening by the end of November. Whilst quite far out you can see from 300hrs to 384 hours it completely starts to disintegrate, this must be Wave 2 activity affecting the vortex as mentioned in the Strat thread.
384hrs
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Some interesting comments from NCEP this evening, some bizarre goings on with the amount of warm air forced into the Arctic circle:
...UNCERTAINTY ASSESSMENT...
FASCINATING 'SHAKE-UP' OR 'RE-SHUFFLE' IN THE WESTERN HEMISPHERIC
CIRCULATION HIGH-LATITUDE FLOW PATTERN TAKING PLACE---STARTED IN
MOTION BY ENERGY AND MOISTURE ORIGINATING IN THE SOUTHWEST PACIFIC
(TROPICAL SYSTEM 'NURI'). THE ENTIRE AIRMASS HAS PUSHED NORTH OF
THE ARCTIC CIRCLE. BARROW ALASKA WAS WARMER EARLIER THIS MORNING
(UTC TIME) THAN AMARILLO TEXAS.
You'll also see comments re teleconnections below:
USING THE WPC TELECONNECTION TOOLS IS INTERESTING---THE POSITIVE
ANOMALY (UPPER-LEVEL HIGH) CENTERED OVER NORTHEAST ALASKA SUGGESTS
MAINTAINING A STEADY DRAW OF CANADIAN ARCTIC AIR INTO
MONTANA...WYOMING AND THE DAKOTAS---SIMILAR TO THE CURRENT
CONDITIONS---THROUGH THE DAY +8/+11 TIME FRAME. CONTRAST THIS TO
THE NEGATIVE ANOMALY---TELECONNECTING THE FORECAST CALLING FOR AN
UPPER-LEVEL LOW OVER SOUTHEAST HUDSON BAY. THE TELECONNECTION
SHIFTS THE ENTIRE COLD 'FOCUS' AT DAY +8/+11 TO THE
MIDWEST...GREAT LAKES AND SOUTHERN PLAINS---ESSENTIALLY THE ENTIRE
LANDMASS AREA EAST OF THE CONTINENTAL DIVIDE. SO THE QUESTION
IS---WHICH ANOMALY TO BASE THE FORECAST ON? OR EVEN BETTER---WHICH
TELECONNECTION IS MORE SIGNIFICANT AND 'UNUSUAL'?
THE UPPER-LEVEL RIDGE IS THERE NOW...AND THE UPPER-LEVEL LOW?
ANOTHER 36 HOURS AWAY AND HARD TO TELL TODAY WITH THE AIR
TEMPERATURES AHEAD OF THE FRONT---ALONG THE EAST COAST
TODAY---UNSEASONABLY MILD.
If the models hold the cold back further west in the USA this then would reflect less eastwards movement of the cold pool. Which would impact the eastern USA and downstream in western Europe.
The last time we had a similar pattern like this.
The amplification allowed for the downstream (Being the UK) - allowed this process to happen.
It's only a matter of time before a pattern change, from what we have at the moment to something more blocked. I agree with Steve Murr's previous comments - 4 weeks seem's a bit long, I just can't see the current pattern holding out much longer with the jetstream being where it is. If it powers up then that's just the way we are going to have to go before something more blocked. I see the stratosphere is going through some changes, that would hopefully propagate downwards. I persume that in 2 weeks time the actual pattern we will have could be very blocked to our North(west/east).
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Looks like at 240hrs, quite a lot warmer over Greenland than normal according to the NCEP. NCEP also goes for a blocked out Arctic. It also shows blocking over Europe with the UK on the edge with blocking to our north. Potentially anything that does change will be very quickly, and I can't wait for the models to start showing an emerging pattern change. Just had a read over at the Strat thread and it looks like anything cold/snow worthwhile is going to be mid-to late December. How festive!!
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Cheers Robbie- I think we are on the same page ish!-
PS
I flew on concorde on a charter flight when I was 8 or 9 @ Mach 2.- on my own!!!!!
Yeah definitely. My only concern is the Jetstream, it's quite far south on the 12z 10th output. But is it to powerful to allow WAA towards Greenland.
Here it is on the ironically similar 12z 14th 2010 output.
Needs to move into this position, but that will only show with a weaker CA Lobe?
How was the Concorde journey? When/Where to/from?
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GFS 120hrs out on 10th November 2010 showed this.
And this is what we got.
It wasn't until the 14th that we started to see something like this come into fruition.
Consider that low pressure to our South West and what it does on the 15th, and have a look at the Scandinavian high. Heights building over Greenland, watch for the link up of the Azores with Greenland. It's not as simple as that but if the Jet across Iberia remains the same and the other half follows the Vortex lobe over Canada into the Arctic then I'd suggest Greenland heights building near the 20th November, but the other way looks to be High pressure over the UK.
I think the 2014 picture looks far easier to a blocked NH than the 2010 route. What happens this weekend with regards to the building of heights is what will likely effect the last two weeks of November.
I see no major difference between the 120hr forecast in 2010 for the 14th of November and today's 120hr forecast for the 10th of November. Literally no major differences. Reading what Steve Murr has put, it's of similar thoughts to me - Day 8-10 looks interesting.
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Tamara's post earlier pretty much outlines exactly where we'll head in NWP terms within the next week plus. A lessening of the -AO is almost a certainty IMO and this is based on what we've seen historically and hints within the extended ensemble suites. It's nothing to be particularly worried about however. The current N hemispheric set up has lit the torch paper so to speak. All that is required now is a bit of patience and to sit back over the next month and watch it unfold.
Will be interesting to see what the MetOffice updates bring each week.
As long as the vortex is split into two lobes with NH over the Artic/Greenland - I cannot see a repeat of last year. Although the positioning of the WAA towards Greenland could be crucial; I think if 84-120hrs verifies anything after this period at the moment being FI - the actual prognosis could be different.
4 years the models have come a very long way, so hopefully it continuous with rising heights.
I think for November - look North not East....
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The potential is definitely there. I suspect the models will drop the idea very soon though and bring it back, just like 2010.
I remember someone mentioning in 2010 the models struggled processing something and it defaulted to raging westerly before coming back for a synoptic dream 7 days from the event. Was it a shortwave that changed the models breifly before coming back online?
Hope someone can answer this.
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GFS is flirting with history. Take a look at this, obviously the dates are different but only by a few days. Actually looking at a the synoptic in the future we are in quite a position moving forward. I seem to remember 2010 was pure synoptic. I actually think the Jetstream over the UK and western Europe is in quite a good position to allow the building of heights over Scandinavia and Greenland. If the low to our south west is to further dig southeast, then we are surely in a good position synopticallly for the end of November 2014?
I expect downgrades, and upgrades if there's any fruition of a cold spell. It's just remarkable how the models are counting down to an event like November 2010. Not saying they two will be the same, just how similar the models are behaving before a possible event.
2010 - 78hrs away
2014 - 78hrs away
2010 -120hrs away
2014 -120hrs away
Here's the NCEP clearing showing heights to our north, northeast.
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I seem to remember a mild period (Didn't we just hit 24*C last week) before a fairly wet period with the models counting down for two weeks showing northern blocking. Re: November 2010
Easterlies/Northerly before throwing away the idea then coming back with something even bigger.
I am intrigued by the similarities of the two months thus far.
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I've had 31, that doesn't include the ones I didn't observe when I was sleeping/inside work.
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My friend Sarah on her way to Stockholm from Heathrow just posted these of the Squall coming through Heathrow.
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depends where you are Robbie been fairly moribund in my neck of the woods
.....Sorry to hear, it's been dire down here for many years. Only recently has it been awesome.
Yep. Reminds me of the summers in the 90's when I was a child.
Summers after 1999 have been terrible for storm activity really, you were lucky if you got one good one a year. 2004 was decent, but this year has been far better.
Yeah I remember those late 90's too, very small and scared of those overnight MCS. Harry and Lauren remember them too thankfully
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Been by far the stormiest Summer in a very very long time...
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London earlier, taken by the BBC Weather team.
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I just left work at Heathrow. Constant lightning from different cells. Thunders here and there and oh torrential rainfall. I'm drenched...
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First rumble of thunder of the day heard here near Croydon, just south of the storm developing towards central London and the bases of the clouds above are getting increasing dark.
More heading northbound Nick? Cell to my South West and West have been moving slow. Poor vis to the south where you are.
Cell over me and Oval Cricket is producing lightning every 5 minutes, raining heavy here.
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Deep rolling thunder and lightning just in the next post code. Flights still going through it.
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Thunder!!!! Quite a few active Cells in London right now.
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Raining quite a bit with Surface Based CBs in London, can't see much as there's plenty of poor visibility but very poor vis to my south at the moment.
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CB's going up in London, very slow moving with precipitation.
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OMG the storm over France is striking around twice a second...midlands storm doing well also
Only need one now here
need an overnight MCS -
The storm west of Rouen right now is huge, It's very very lively. Wish we had that here
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Any chance of a new thread, this one is huge :O
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Model Output Discussion 1200 hrs 15/11/14
in Forecast Model Discussion
Posted
I for one cannot understand why the models are struggling so much. It has to be the pattern we currently have going forward, but it's so close yet so far away from developing into strong Northern Blocking. If that low to our SW digs further SE then we are in, as long as the Azores ridges north.