12Z models 12/18/10

[BaltimoreWxGuy]

at 120 hrs at 500 MB you could argue that so yes you do have a Point.

BUT clearly northern stream energy from sw and s central Canada does drop into or 'PHASE" in the s/w in the STJ crossing the Rockies

it is the phasing that makes the system go BOOM as it closes off A 500 LOW when it cross the Mississippi river at 144 hrs as it goes 'NEUTRAL"

OK, fair enough...I just figured it was valid to point out because I would think a system with its energy resulting from the west coast rather than a clipper coming out of Canada would be more robust and have more moisture to work with, but as you pointed out, I suppose both players are a big factor,

[jlewis1111]

whats ur take dt on this storm with the models for xmas wknd

[usedtobe]

The GFS deciption of this system being THAT strong is fooking crazy and without ANY basis in fact.

None

zero ...

aModerate decent clipper? ... sure.

976 MB!?!?!?!? come on folks

It might be unlikely but the cpc D+8 analogs which are based on the mean 500 pattern for the 5 days centered on Dec 26 have 2 KU storms of the 10 analogs which suggest despite us being a a nina, the probability of a 4 inch or greater storm at dca is quite a bit higher than climo of 6 such events in 123 years and the climo for a KU storm is probably lower than that. So the storm threat is definitely worth watching and is more worthy of interest than the dec 19 event was. Sure, the odds are strongly stacked against such a strong storm in a nina year but stranger things have happened. If the probability of a KU storm is only 10 percent that's still pretty significant at such a long time range.

[Ender]

It might be unlikely but the cpc D+8 analogs which are based on the mean 500 pattern for the 5 days centered on Dec 26 have 2 KU storms of the 10 analogs which suggest despite us being a a nina, the probability of a 4 inch or greater storm at dca is quite a bit higher than climo of 6 such events in 123 years and the climo for a KU storm is probably lower than that. So the storm threat is definitely worth watching and is more worthy of interest than the dec 19 event was. Sure, the odds are strongly stacked against such a strong storm in a nina year but stranger things have happened. If the probability of a KU storm is only 10 percent that's still pretty significant at such a long time range.

The change in the analog date set is pretty dramatic. We suddenly have several "great dates" showing up while we been lucky to pull off a single so-so analog date is most the CPC D8 lists in the past almost two months. Of course, they have to have the D8 composite forecast correct or these analogs are meaningless.

[SnowGoose69]

Any guesses as to when the GFS loses the storm for 2-3 days in classic mode? I'd say within the next 4 runs.

[gymengineer]

It might be unlikely but the cpc D+8 analogs which are based on the mean 500 pattern for the 5 days centered on Dec 26 have 2 KU storms of the 10 analogs which suggest despite us being a a nina, the probability of a 4 inch or greater storm at dca is quite a bit higher than climo of 6 such events in 123 years and the climo for a KU storm is probably lower than that. So the storm threat is definitely worth watching and is more worthy of interest than the dec 19 event was. Sure, the odds are strongly stacked against such a strong storm in a nina year but stranger things have happened. If the probability of a KU storm is only 10 percent that's still pretty significant at such a long time range.

I wish we had access to the pinned Eastern threads you made last winter about each of the big snow threats. Do you remember off the top of your head how many big snowstorms were showing up on the analogs for, say, the 2/5-6 or 12/19 storms? Didn't 2/83 show up for both?

[BaltimoreWxGuy]

Any guesses as to when the GFS loses the storm for 2-3 days in classic mode? I'd say within the next 4 runs.

Maybe Im being overly optimistic, But I dont think the GFS loses this one, sure the track may waffle a bit here and there but I think the general idea sticks....cyclogensis might not occur on future runs but this type of storm could still produce a decent snow without it.

[usedtobe]

The change in the analog date set is pretty dramatic. We suddenly have several "great dates" showing up while we been lucky to pull off a single so-so analog date is most the CPC D8 lists in the past almost two months. Of course, they have to have the D8 composite forecast correct or these analogs are meaningless.

True but i think that's easier to do than get the a single day mean pattern right so I think the suggestion of an increased threat is right. Of course at this time range, a probability of a 4 inch or greater event is small because the climo probalities are so low. A probability of 20% would be about 4 times the normal climo for the 5 day period.

[Dsnowx53]

The thing with this event is that we actually have a semblance of a west-coast ridge. That would mean that northern stream energy dropping down is more likely than it was for this past event. The whole PV could never drop down like the D+7 model runs were showing, partially because there was no ridge to its west to force it southward. This time around, we (hopefully) DO have a ridge to its west that can force it southward, so the situation is not nearly as delicate as it was for the Dec. 19th "threat".

[Caveman]

I do believe the super ensembles enable a forecaster to add another powerful tool to one's plethora of data that is available in this day in age. The large scale Synoptics of the upper air pattern can certainly support and even create the necessary physics to manifest the surface depiction of the analog dates. I personally think analogs certainly show good correlation between upper atmospheric synoptics and surface reflections although I do not have much research to support this theory.

[usedtobe]

I wish we had access to the pinned Eastern threads you made last winter about each of the big snow threats. Do you remember off the top of your head how many big snowstorms were showing up on the analogs for, say, the 2/5-6 or 12/19 storms? Didn't 2/83 show up for both?

I wish I had them also, I did save some that were prior to the event but were centered beyond both of them. I remember 5 dates for the dec 19 storm and 3 for the feb 5th storm. Sadly, I had posted earlier times than the one I saved for the dec 19th event that included the 5 dates but they got blown awy during the period when easternwx crashed and marcus had to get rid of much of the excess baggage in the form of images.

[usedtobe]

The gfs 12Z ensembles really like some kind of storm and are in better agreement than with the last storm. One caveat, at these time ranges, the ensembles often do not have enough spread so it's likely that the next run or two will show more variation than this one. If they don't, then we can probalby assume the predictability of this storm will be higher than was present the sunday mostly non event.

[mdsnowlover]

wes, with due respect to you, what does hpc have to say about the possibility. ??I greatly respect you discussion here, and there maybe a possibility, due to your reasoning.

[Guest someguy]

whats ur take dt on this storm with the models for xmas wknd

see other thread....

[Guest someguy]

ANYONE SEE THE 0Z EURO ENSEMBLE MEAN ?

not too shabby abby

[icebreaker5221]

At 72 hrs there are already HUGE differences between the GFS and the EURO with regards to the Midwest clipper.

[Wow]

Euro @ 96... enter the southern s/w

[Wow]

compared to 12z GFS:

[mdsnowlover]

ANYONE SEE THE 0Z EURO ENSEMBLE MEAN ?

not too shabby abby

is it assumed that the depicted surface low will go west to east??

[usedtobe]

wes, with due respect to you, what does hpc have to say about the possibility. ??I greatly respect you discussion here, and there maybe a possibility, due to your reasoning.

They take a low to the TN valley by day 7 so it sounds like they are on the same wavelength.

[Wow]

Euro @ 144 hrs. I like the HP nosing in over the east coast.

[Guest someguy]

168 HRS 12Z EURO SIGNIFICANT LOW OVER EASTERN SC

500 trough phasing

0 850 on va nc state line RIC -4C DCA -6C NYC -8C

[Guest someguy]

180 HRS LOW FLIES OFF NC COAST 500 Low does NOT close off

[LakeEffectKing]

168 HRS 12Z EURO SIGNIFICANT LOW OVER EASTERN SC

500 trough phasing

0 850 on va nc state line RIC -4C DCA -6C NYC -8C

[Terpeast]

180 HRS LOW FLIES OFF NC COAST 500 Low does NOT close off

Sounds like a more suppressed track by 12z ec

[RedSky]

sounds supressed south like almost half the GFS ensembles

[jlewis1111]

like the canadian

[Guest someguy]

12z GFS ENSEMBLE MEAN is pretty bullish as well

[jlewis1111]

Hear we go again seems like the same spot we where in last week for tomorrow's big event. Urg I hope something comes out of this pattern for next wkdn

[weathervswife]

QPF?