Christmas Storm V

[DopplerWx]

Now see, that is something that gets my attention right there. If this trend were to change(and I doubt it will), you need to file that quote.

And also when he said, "sometimes these southern stream systems are more resilient than the models give them credit for".

[Shawn]

Now see, that is something that gets my attention right there. If this trend were to change(and I doubt it will), you need to file that quote.

Weather models are always just a tool. Many human elements and thoughts must go into a forecast and anything can happen regardless of what a model says. We could wake up the morning after Christmas and have a foot of snow or nothing. I really don't believe the models are going to 100% accurately predict when this thing will phase if it does. So many factors involved that well, we just can't figure out until it's too late haha.

[Jalba]

Link to the GFS Ensembles

http://raleighwx.americanwx.com/models/gfsensemble/members/12zf066.html

This ones the best lol.

[Carvers Gap]

Per HPC, Thursday Afternoon...

EXTENDED FORECAST DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

136 PM EST THU DEC 23 2010

VALID 12Z SUN DEC 26 2010 - 12Z THU DEC 30 2010

...CONTINUED WET ALONG THE WEST COAST...

...WINTER STORM STILL POSSIBLE ALONG THE EAST COAST SUN-MON...

THE VIGOROUS UPPER TROUGH AND ITS ACCOMPANYING INTENSE POLAR JET

STREAM ARE EXPECTED TO FACILITATES DEAMPLIFICATION OF THE LONGWAVE

PATTERN OVER THE CONUS THROUGH MUCH OF THE MEDIUM RANGE PERIOD

BEFORE REAMPLIFYING TOWARD A TROUGH/RIDGE PATTERN OVER THE

WESTERN/EASTERN CONUS RESPECTIVELY BY DAY 7.

IN THE WEST...PRECIPITATION WILL LIKELY REMAIN ABOVE AVERAGE.

HOWEVER...DETERMINING THE EXACT TIMING/LOCATION OF INDIVIDUAL

EVENTS REMAINS IN QUESTION. SOLUTION SPREAD IS ALREADY ABOVE A

COMFORTABLE LEVEL TO BE PARTICULARLY CONFIDENT ENTERING DAY 3 WITH

MODEL GUIDANCE INDICATING AN INTENSE SPLIT-TROUGH ENTERING THE

REGION...WHICH IS SIMILAR FROM WHAT CROSSED THE WEST YESTERDAY.

THE 00-06Z GFS LIE NEAR THE FAST EDGE OF THE GUIDANCE WITH THE

LEADING EDGE OF THE TROUGH...THE 12Z GFS TRENDING SLOWER...AND ALL

OTHER DETERMINISTIC AND ENSEMBLE GUIDANCE...ALONG WITH THE

HIGH-AMPLITUDE BLOCKED FLOW DOWNSTREAM SUGGESTING THAT THE

SLOWER/DEEPER CAMP OF SOLUTIONS MAY BE MORE ACCURATE. IN

FACT...THE 00-12Z UKMET WHICH INDICATE A SEPARATED AND SOMEWHAT

MATURE CYCLONE MOVING INTO CALIFORNIA AND THE SOUTHWEST SEEMS MOST

REASONABLE GIVEN THE LONGWAVE FLOW...WITH THE 00Z ECMWF/CANADIAN

SLIGHTLY WEAKER AND FASTER BUT STILL PLAUSIBLE.

OTHERWISE...NORTHERN PORTIONS OF THE TROUGH ARE EXPECTED TO

PROGRESS THROUGH THE NORTHWEST WITH SLIGHTLY FASTER TIMING...WITH

NEUTRAL/ZONAL FLOW SPREADING INTO THE ENTIRE WEST FOR ABOUT 48 HRS

BEFORE ANOTHER SIGNIFICANT AND AMPLIFYING TROUGH ENTERS THE WEST

BY THE END OF THE PERIOD. THE 00Z GFS IS A LITTLE FASTER THAN THE

00Z ECMWF WITH THE LEADING EDGE OF THE REAMPLIFYING TROUGH

REACHING THE NORTHWEST BUT OTHERWISE MERGES NICELY WITH IT BY END

OF DAY 7...WITH THE GFS/ECMWF GLOBAL ENSEMBLE MEANS IN PHASE WITH

THEIR DETERMINISTIC MEMBERS. IF THEY ARE CORRECT...A SNOW STORM IS

LIKELY

FOR PORTIONS OF THE CENTRAL/NORTHERN ROCKIES BY DAY 7.

IN THE EAST...MODEL SPREAD HAS CONTINUED TO NARROW CONCERNING THE

TRACK AND OTHER DETAILS OF A POTENTIAL WINTER STORM AFFECTING THE

EAST COAST DAYS 3-4...WITH THE MOST NOTICEABLE AND CONSISTENT

MODEL TREND OBSERVED FOR FASTER NORTHEASTWARD ACCELERATION.

EARLIER PREFERENCES WERE FOR A SCENARIO CLOSEST TO THE 06Z GFS

WHICH REPRESENTED AN AVERAGE OF THE MOST WESTWARD 00Z ECMWF AND

MORE EASTWARD 00Z GFS...WITH THE LAST SEVERAL RUNS OF THE

UKMET/CANADIAN SOUTH AND/OR EAST OF AN OTHERWISE NARROWING CLUSTER

OF GUIDANCE AND THUS WERE NOT SERIOUSLY CONSIDERED. DESPITE

IMPROVED CLUSTERING OF SOLUTIONS AND SOME CONSISTENCY IN

TRENDS...IT REMAINS PREMATURE TO PICK A SPECIFIC DETERMINISTIC

SOLUTION WITH HIGH CONFIDENCE. THE TROUGH APPROACHING THE REGION

HAS ONLY RECENTLY ENTERED THE MORE DENSELY POPULATED OBSERVATIONAL

NETWORK...AND THUS IT WILL PROBABLY TAKE ANOTHER 1 OR 2 MODEL RUNS

AT LEAST TO RESOLVE THE MULTIPLE STREAM INTERACTIONS WHICH IS

CRUCIAL TO A SUCCESSFUL FORECAST IN THIS SHORTWAVE PATTERN.

THUS...THE FINAL PRESSURES/FRONTS WERE ONLY NUDGED ABOUT MIDWAY

BETWEEN THE 06-12Z GFS...WHICH CREDITS THE NEW CONSENSUS FOR A

FASTER SOLUTION WHILE ALSO MAINTAINING CONTINUITY AS THE PRECISE

TRACK FORECAST STILL CONTAINS A LARGE AMOUNT OF UNCERTAINTY.

There you go. Now, we get to stay up late for another 0z run of the Euro...

[DopplerWx]

Weather models are always just a tool. Many human elements and thoughts must go into a forecast and anything can happen regardless of what a model says. We could wake up the morning after Christmas and have a foot of snow or nothing. I really don't believe the models are going to 100% accurately predict when this thing will phase if it does. So many factors involved that well, we just can't figure out until it's too late haha.

Yeah, and the amount of changes in the models in just 24 hours in unreal. No doubt theyll continue to change. If the models continue to trend further east and drier thru 00z tonight then we should start worrying, until then just wait for the 18z runs.

[strongwxnc]

Good find. I see Five total that shows a good to great run for our area. But yes, The one you picked is very nice.

+ reading the HPC thoughts on the NS coming and and getting better sampled.. Well, down to the wire folks..

Link to the GFS Ensembles

http://raleighwx.ame...rs/12zf066.html

This ones the best lol.

[WidreMann]

The Euro isn't terrible. I think the days of a big day are over. But this could still be non-trivial snow event for a lot of central and eastern NC into southern VA and down into N Ga and SC.

[Blue_Ridge_Escarpment]

Here is the QPF total for the GFS Ensemble p001 shown above:

[Snow haven]

when do you think (if ever) the models will have a better understanding of this storm? I have family coming in from florida and were wondering if they needed to leave early to avoid this the snow. or will it cause that much of trouble. I want all the snow we can get but i also want them to be safe. I know things are not looking like they did yesterday, but how many times in the past have storms done the opposite of what we thought? let me know what you guys think about the traveling part from florida. Im not worried about amount.

[Brick Tamland]

The Euro isn't terrible. I think the days of a big day are over. But this could still be non-trivial snow event for a lot of central and eastern NC into southern VA and down into N Ga and SC.

I agree. Everyone locked onto the Euro because of what it showed the last couple of days. But the models are really all different and are going all over the place now. We have no idea what will really happen now, and we really didn't have an idea of what would happen when the Euro was showing a monster storm. It's still most likely going to snow somewhere in the SE on Christmas, probably in NC and VA. We just don't have any idea of how much, and we never really did,

[Shawn]

when do you think (if ever) the models will have a better understanding of this storm? I have family coming in from florida and were wondering if they needed to leave early to avoid this the snow. or will it cause that much of trouble. I want all the snow we can get but i also want them to be safe. I know things are not looking like they did yesterday, but how many times in the past have storms done the opposite of what we thought? let me know what you guys think about the traveling part from florida. Im not worried about amount.

I think a lot of people like myself are going to give you the not sure route. So many factors involved in this. Some people will see snow but how much and where at are still extremely volatile.

[Pilotwx]

Okay I'm going to make a call based on the 500mb 48hr EURO. I think the storm will be North of Houston @ 48 instead of LA Coast. If you look @ the contour lines and trough axis it seem to be more North and West than where the Euro puts the Lows, or where it captures the low. So for this reason I'm not giving in just yet!

I'm going to quote you and post images accordingly...

@48hr

[strongwxnc]

This is a local met who does a great job at his job.

again from Andy Wood at Fox 21 (GSP location)

http://foxcarolinaweather.wordpress.com/2010/12/23/afternoon-thought/

"I would strongly advise keeping a close eye on this Southern Stream (pacific-originating) Storm as it moves across the desert southwest and into Texas. Data may be under-playing the strength of it a bit… or quite a bit. I say this especially since a few very well-respected forecasters in the northeastern US have mentioned it this morning. One thing is for sure… this roller-coaster ride isn’t over.

_______________________________

…just saw this discussion below after I typed what I typed above…

HPC Discussion

-Hydrometeorological Prediction Center in Maryland-

IT REMAINS PREMATURE TO PICK A SPECIFIC DETERMINISTIC

SOLUTION WITH HIGH CONFIDENCE. THE TROUGH APPROACHING THE REGION

HAS ONLY RECENTLY ENTERED THE MORE DENSELY POPULATED OBSERVATIONAL

NETWORK…AND THUS IT WILL PROBABLY TAKE ANOTHER 1 OR 2 MODEL RUNS

(AT LEAST) TO RESOLVE THE MULTIPLE STREAM INTERACTIONS WHICH IS

CRUCIAL TO A SUCCESSFUL FORECAST IN THIS SHORTWAVE PATTERN.

Again, two jetstreams in a split flow with energy flying all over the place like a crazed painter throwing buckets of paint on a wall. I am dead serious… that is about as close to accurate as what we have in the upper levels.

Here’s what we know: there will be cold air very much in place… we know there is a storm, but the only question is “how strong” of a storm & “how far off the coast is it going to track”. "

[superjames1992]

Does anyone have any information on the 12z Euro ensembles?

[eyes2theskies]

Eagerly awaiting all of the Afternoon disco's should be interesting and curious to see when GSP issues a winter storm watch

[strongwxnc]

I doubt they will. If anything and I mean anything a wwa or a sps... but

Eagerly awaiting all of the Afternoon disco's should be interesting and curious to see when GSP issues a winter storm watch

[tarheelwx]

I think we're all still in the game here. Time for the northwest trend to begin.

Enough of the "as long as DC to Boston don't get it" stuff. Let's at least hope that if we can't get it in the southeast that those up northeast get pounded - they deserve it after last winter. I'd hate to think that they built up their back muscles for nothing. Also, who's to say that in a couple of weeks we don't have a hp over the northeast with precip moving in and borderline temps and we need just an extra degree or 2 to have frozen/freezing precip - it could all boil down snow cover to our northeast. So, let's have the spirit of Christmas and want snow for all!!!

Merry Christmas,

TW

[Jalba]

Hopefully Fixed now.

From 6am - 2pm.

[Pilotwx]

Does anyone have the position of the low out west and the one to the north. Someone had posted a map of the actual location this morning?

[eyewall]

From WRAL:

Snow is still in the forecast for this weekend but it is not looking like a significant snowfall...am not going to call off the dogs yet as we have a couple days to go til it arrives...the latest at 5PM on WRAL-TV.

IE their walk down has begun as well.

[strongwxnc]

Looks to be moving due east....

Killer Loop

Hopefully Fixed now.

From 6am - 2pm.

[Pilotwx]

I think I just found something that may have a MAJOR in pact on the on going forecast! Look to the NE on the WV I am linking to. The storm in NF looks to be retrograding back south and east ( maybe wrong) but looks to me that it is. This may bottle up the upper air features and slow the progression of the Low to the NW and West, so they might both get captured into one storm.

http://www.goes.noaa.gov/GSSLOOPS/ecwv.html

[Solak]

Does anyone have the position of the low out west and the one to the north. Someone had posted a map of the actual location this morning?

Time sensitive, I think...

[Solak]

[Jalba]

I'll probably stick to looping this national image instead. Looks better. I'll keep adding the hours to it, as long as the .gif is not too big

BTW NAM Starting...

[superjames1992]

I think I just found something that may have a MAJOR in pact on the on going forecast! Look to the NE on the WV I am linking to. The storm in NF looks to be retrograding back south and east ( maybe wrong) but looks to me that it is. This may bottle up the upper air features and slow the progression of the Low to the NW and West, so they might both get captured into one storm.

http://www.goes.noaa...LOOPS/ecwv.html

Interesting find. I don't know if it will make any difference, but I certainly hope so. I don't believe this was forecasted by the models.

[AirNelson39]

I think we're all still in the game here. Time for the northwest trend to begin.

Enough of the "as long as DC to Boston don't get it" stuff. Let's at least hope that if we can't get it in the southeast that those up northeast get pounded - they deserve it after last winter. I'd hate to think that they built up their back muscles for nothing. Also, who's to say that in a couple of weeks we don't have a hp over the northeast with precip moving in and borderline temps and we need just an extra degree or 2 to have frozen/freezing precip - it could all boil down snow cover to our northeast. So, let's have the spirit of Christmas and want snow for all!!!

Merry Christmas,

TW

+1 couldn't agree more!!

Merry Christmas

[Pilotwx]

Thanks!

[Itunis]

FFC notes the decreasing moisture in their aftn disco but isn't giving up quite yet.

[NEGa]

FFC notes the decreasing moisture in their aftn disco but isn't giving up quite yet.

it obviously now looking like there wont be a lot of moisture probably, but still likes a white christmas is possible in parts of n ga and still have a chance of some snow. while i would love a biggie, of course, even a couple of inches would be really nice even if its not warning criteria