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Arctic Outbreak (Second Try)


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2 F? I go out in shorts and a T in that weather thumbsupsmileyanim.gif

Yeah, it's kind of funny that Grand Forks was below zero all day yesterday, and about -20F at night...but we're not even talking about that. GFK is just cold without even "trying"...the climate differences between the northern plains and midwest are amazing.

If we had a day in Chicago of -2/-20, it would seem like the world is ending. But in GFK, it's just a run-of-the-mill cold airmass...no big deal. :snowman:

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:whistle:

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

204 PM EST MON JAN 10 2011

VALID 12Z THU JAN 13 2011 - 12Z MON JAN 17 2011

...12Z MODEL CYCLE UPDATE...

NO SIGNIFICANT CHANGES WERE MADE TO THE MORNING PACKAGE...ALTHOUGH

A SOUTHWARD ADJUSTMENT WAS MADE AT DAY 7 WITH THE FRONTAL

BOUNDARY. THIS WAS IN RESPONSE TO THE TREND NOTED IN THE 12Z GEFS

MEAN/CMC. IN ADDITION...FROM PREVIOUS EXPERIENCE...THE SOUTHWARD

PENETRATION OF MODIFIED ARCTIC AIR ALWAYS SEEMS TO BE

UNDERESTIMATED BY MODEL GUIDANCE. SO ADJUSTING THE FRONTAL SYSTEM

ACCORDINGLY APPEARED THE WAY TO GO.

WITH THE CLIPPER-LIKE SYSTEM MOVING THROUGH THE UPPER GREAT LAKES

ON SATURDAY...THE 12Z GFS HAS TRENDED TOWARD A FLATTER SOLUTION

ALOFT WHICH LEADS TO LESS SURFACE CYCLOGENESIS. HOWEVER...BEFORE

THIS OCCURS...THE GFS DEPICTED A SFC LOW WHICH WAS SIGNIFICANTLY

STRONGER WHILE CROSSING THE NORTHERN PLAINS. THIS IDEA WAS ALSO

SUPPORTED BY THE 12Z ECMWF. HOWEVER...NO ADJUSTMENTS TO THE

PRODUCTS WERE MADE GIVEN THE LARGE SCATTER IN THE INTENSITY

FORECASTS FROM THE GFS/ECMWF DURING THEIR LAST SEVERAL RUNS.

ONE OTHER NOTE TO MAKE IS THE FACT THE 12Z GEFS MEAN HAS PULLED

EVEN FURTHER TO THE EAST AT DAY 7 WITH THE RIDGE OVER THE EASTERN

PACIFIC. THIS HAS THE EFFECT OF INCREASING THE SPREAD BETWEEN THAT

AND THE 00Z ECMWF ENSEMBLE MEAN. AT THIS TIME...THE ORIGINAL

FORECAST BLEND WILL BE MAINTAINED.

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Yeah, it's kind of funny that Grand Forks was below zero all day yesterday, and about -20F at night...but we're not even talking about that. GFK is just cold without even "trying"...the climate differences between the northern plains and midwest are amazing.

If we had a day in Chicago of -2/-20, it would seem like the world is ending. But in GFK, it's just a run-of-the-mill cold airmass...no big deal. :snowman:

ya you get used to it, i didn't even wear a jacket when i headed into my office today, just my hoodie and we might get up to a blistering 10 degrees today. :thumbsup:

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The Ops have been lost. I suspect it's a bit too soon to discount an Arctic Intrusion into the Lower 48. We shall see.

As I hve been saying, the Pacific is becoming favorable for a cold pattern E of the Rockies...If you want cold to go far south, the 10 day Euro is a step in the right direction. Says "what +EPO" and break of the -NAO pattern? This time with <-35C temps in Canada

00zECMWF500mbHeightAnomalyNA240.gif

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You beat me to it. Severe artic plunge delayed but not denied? 850mb -40C pop for the first time this season, and with the W coast ridge, it's gonna head south unadulterated this run.

Nice...the "vodka isotherm" makes an appearance. :guitar:

The 10-day Euro is definitely interesting...need to see if it can hold for a run or two.

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And my buddy 57 is calling for a warmup...:arrowhead:

Many bought the drastic EPO switch, but forgot to look at the tropics. Even though it goes against the current ENSO state, a coherent MJO wave in all models is forecasted to go trough phases 7 and 8. This helps Indonesia to dry out a bit, while switching the -OLR anomalies closer to the dateline. This is very nicely modeled in the GEFS, with the bulk of the tropical forcing around the dateline. This usually promotes an Aleutian low and ridging in the W Coast of North America. That, plus having a disturbed stratosphere argues against the AO going positive, so the EPO ridge doesn't fully migrate to Siberia, and that's how we still have cross polar flow and a supressed PV in Central Canada, plus all the cold air that is currently being transferred to Canuck land are a recipe for some strong cold. Not etched on stone, but this is, IMO, more reasonable than a huge warmup.

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Many bought the drastic EPO switch, but forgot to look at the tropics. Even though it goes against the current ENSO state, a coherent MJO wave in all models is forecasted to go trough phases 7 and 8. This helps Indonesia to dry out a bit, while switching the -OLR anomalies closer to the dateline. This is very nicely modeled in the GEFS, with the bulk of the tropical forcing around the dateline. This usually promotes an Aleutian low and ridging in the W Coast of North America. That, plus having a disturbed stratosphere argues against the AO going positive, so the EPO ridge doesn't fully migrate to Siberia, and that's how we still have cross polar flow and a supressed PV in Central Canada, plus all the cold air that is currently being transferred to Canuck land are a recipe for some strong cold. Not etched on stone, but this is, IMO, more reasonable than a huge warmup.

We've seen many a bust with the pattern and the 'mechanics' at work on a global scale are very interesting to watch unfold. Now let's see if the goods can get delivered.

post-32-0-22469200-1294775240.gif

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GB AFD:

IT/S DEFINITELY BEEN A STRUGGLE GETTING A HANDLE ON THE POTENTIAL

FOR BITTERLY COLD TEMPS. AT SEVERAL POINTS DURING THE PAST COUPLE

WEEKS...MODELS HAVE INDICATED A MAJOR ARCTIC INTRUSION JUST BEYOND

THE END OF THE FCST PERIOD. BUT THUS FAR...ALL WE/VE ENDED UP

DOING IS PUTTING THE COLD AIR OFF FARTHER INTO THE FUTURE. MODELS

HINTING AT THE SAME THING AGAIN TDA...AND STARTING TO WONDER IF WE

ARE IN FOR ANOTHER TEASE. PART OF THE PROBLEM MAY BE RELATED TO

THE DOMINANT PATTERN WE WERE IN FOR THE PAST SEVERAL WEEKS.

ALTHOUGH THE STG RIDGING OVER AK WOULD NORMALLY RESULT IN VERY

COLD AIR SPILLING INTO THE NRN CONUS...WE DIDN/T START WITH VERY

COLD AIR ACRS MUCH OF CANADA. IN FACT...THE STG/PERSISTENT

BLOCKING OVER ERN CANADA AND THE N ATL ACTUALLY BROUGHT AIR FM THE

ATLANTIC ACRS MUCH OF ERN AND EVEN INTO CENTRAL CANADA...AND THAT

AIR MASS WAS ACTUALLY MILD /RELATIVELY SPEAKING/ FOR THIS TIME OF

YEAR. NOW THAT AK RIDGE HAS BEEN IN PLACE OF A WHILE...COLD AIR

RESERVES ARE RAPIDLY INCRG OVER NWRN CANADA...THOUGH INITIAL SURGE

OF COLD AIR GETS SHOVED BACK WWD INTO THE CANADIAN ROCKIES. IT IS

INTERESTING TO NOTE THAT ANIMATIONS OF THE NORTHERN HEMISPHERIC

FLOW OFF THE PAST FEW RUNS OF THE ECMWF...GFS...AND CANADIAN

MODELS ALL SHOWED A CHUNK OF VERY COLD AIR FM NERN SIBERIA

BREAKING OFF AND HEADING SWD THROUGH CANADA LATE THIS WEEKEND AND

EARLY NEXT WK...LEAVING IT POISED OVER THE CANADIAN PRAIRIE

PROVINCES BY LATE NEXT WK. WITH DEEP VORTEX PROGGED TO BE IN

HUDSON BAY AREA AT THAT TIME...PERHAPS THE COLD SNAP THAT ALWAYS

SEEMS TO BE JUST BEYOND THE HORIZON WL FINALLY MATERIALIZE. WE/LL

SEE.

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