December 17th Clipper Discussion

[CoastalWx]

Not really....RGEM/GGEM have apparently been the biggest outliers the entire time.  They were running the low across RI for several runs.

 

It's still progressive is what I mean. 

[weathafella]

Harv seemed confident. 4-6.

[Clinch Leatherwood]

It's still progressive is what I mean. 

 

True but even the Euro had amped up the 2nd s/w markedly at 12z..and dampened out the first one.  GGEM...well....I think they're just lagging.

 

Odd that in this pattern the models can never really catch up until they're inside of 12 hours.

 

I'd like to see the GEFS support the GFS and have the UK or EURO continue to come towards the more prolonged idea of snow...

[weatherwiz]

Yeah i saw that too. Not sure that's the best move.

 

It's an enticing idea but not really convincing enough to go right ahead and do it without seeing some other support.  If some had like 2-4'' range for parts of E. MA and wanted to bump that up I could see that but seeing some totals going 6''+ might be going a little bit overboard right now.   

[wxsniss]

Hedging as much as everyone here:

 

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1120 PM EST MON DEC 16 2013

 

00Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z
NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.


CYCLONE BOMBING NEAR NEW ENGLAND/ATLANTIC CANADA
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: CLOSEST TO THE 21Z SREF MEAN
CONFIDENCE: BELOW AVERAGE

THE LAST COUPLE RUNS OF THE GFS HAVE TRENDED STRONGER WITH THIS
SYSTEM -- SO MUCH SO THAT IT IS ABOUT A DOZEN HPA DEEPER THAN THE
REMAINDER OF THE GUIDANCE WEDNESDAY AND ON THE SLOW/DEEP SIDE OF
THE 12Z GLOBAL ENSEMBLE GUIDANCE. IN CONTRAST TO YESTERDAY, THE
12Z ECMWF IS THE QUICKEST/WEAKEST SOLUTION. ALOFT, A SIGNIFICANT
CHUNK OF MID-LEVEL ENERGY IS MOVING QUICKLY THROUGH CENTRAL QUEBEC
ON THE WEST SIDE OF A BLOCKING RIDGE. THIS LEAVES ENOUGH ROOM FOR
A SHORTWAVE UNDER ITS BASE TO POTENTIALLY CUT OFF -- MEANING THE
GFS CANNOT BE COMPLETELY DISCOUNTED. HOWEVER, CAUTION IS ADVISED
IN COMPLETELY BUYING OFF ON SUCH A SOLUTION, REGARDLESS OF WHAT
THE PATTERN MIGHT ALLOW. AS THE COURSE OF LEAST REGRET, PREFER AN
INTERMEDIATE SOLUTION SUCH AS THE 21Z SREF MEAN -- MAYBE SLIGHTLY
STRONGER -- WITH BELOW AVERAGE CONFIDENCE CONSIDERING THE ABOVE
AVERAGE MODEL SPREAD FOR A SYSTEM SO FAR WITHIN THE SHORT RANGE
PERIOD.

[CoastalWx]

True but even the Euro had amped up the 2nd s/w markedly at 12z..and dampened out the first one.  GGEM...well....I think they're just lagging.

 

Odd that in this pattern the models can never really catch up until they're inside of 12 hours.

 

I'd like to see the GEFS support the GFS and have the UK or EURO continue to come towards the more prolonged idea of snow...

 

I actually like Harvey's numbers. I think we can hold there for now unless the other guidance comes in more bullish. The GFS could be right..but something scares me about this. We'll find out in a little over an hour.

[Typhoon Tip]

Hedging as much as everyone here:

 

MODEL DIAGNOSTIC DISCUSSION

NWS WEATHER PREDICTION CENTER COLLEGE PARK MD

1120 PM EST MON DEC 16 2013

 

00Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE 12Z

NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS.

CYCLONE BOMBING NEAR NEW ENGLAND/ATLANTIC CANADA

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

PREFERENCE: CLOSEST TO THE 21Z SREF MEAN

CONFIDENCE: BELOW AVERAGE

THE LAST COUPLE RUNS OF THE GFS HAVE TRENDED STRONGER WITH THIS

SYSTEM -- SO MUCH SO THAT IT IS ABOUT A DOZEN HPA DEEPER THAN THE

REMAINDER OF THE GUIDANCE WEDNESDAY AND ON THE SLOW/DEEP SIDE OF

THE 12Z GLOBAL ENSEMBLE GUIDANCE. IN CONTRAST TO YESTERDAY, THE

12Z ECMWF IS THE QUICKEST/WEAKEST SOLUTION. ALOFT, A SIGNIFICANT

CHUNK OF MID-LEVEL ENERGY IS MOVING QUICKLY THROUGH CENTRAL QUEBEC

ON THE WEST SIDE OF A BLOCKING RIDGE. THIS LEAVES ENOUGH ROOM FOR

A SHORTWAVE UNDER ITS BASE TO POTENTIALLY CUT OFF -- MEANING THE

GFS CANNOT BE COMPLETELY DISCOUNTED. HOWEVER, CAUTION IS ADVISED

IN COMPLETELY BUYING OFF ON SUCH A SOLUTION, REGARDLESS OF WHAT

THE PATTERN MIGHT ALLOW. AS THE COURSE OF LEAST REGRET, PREFER AN

INTERMEDIATE SOLUTION SUCH AS THE 21Z SREF MEAN -- MAYBE SLIGHTLY

STRONGER -- WITH BELOW AVERAGE CONFIDENCE CONSIDERING THE ABOVE

AVERAGE MODEL SPREAD FOR A SYSTEM SO FAR WITHIN THE SHORT RANGE

PERIOD.

 

That was titled the 12z guidance, yo -

[40/70 Benchmark]

Will, quick OT, but how much did you end up with yesterday?

[CoastalWx]

Ukie isn't really biting either. I think the GFS is too aggressive.

 

Well I can't see 6hr QPF, so it might be more bullish between 00z and 06z. But, it doesn't seem GFS-like.

[weathafella]

Uncle looks decent. Hard to know what happens because you can't see qpf 24 to 30 but it looks robust.

[eduggs]

The 0z GFS looks very similar to 18z.  Maybe a touch more wrapped up and wetter for eastern sections.  It certainly didn't regress, but claims that it was another big jump are overstated.  But it certainly is interesting as is.  And considering some of the stronger/wetter members of the 18z GEFS suite, this still has a little room to improve further.  Then again, the other guidance still doesn't completely support a longer, possibly more significant event.

[Clinch Leatherwood]

I actually like Harvey's numbers. I think we can hold there for now unless the other guidance comes in more bullish. The GFS could be right..but something scares me about this. We'll find out in a little over an hour.

 

Scott I like his numbers too.  IMO we already know where the Euro is going.  Check the 36h 12z Euro at 500mb vs the 48h 0z from the other night.  Now lay that over the 12z/18z/0z GFS runs.  The Euro and GFS are very similar with the diving energy what's different is some of these models still give some gusto to that lead s/w.  The GFS kills it.  That's either the GFS picking up on the trend prior to the other models or it's out to lunch and the Euro will be some version of the RGEM/NAM.

 

It's a mystery to me why this is so problematic at such short range.

[weathafella]

I thought uk looked ok especially at 500. Not exactly gfs but not far off.

[CoastalWx]

I thought uk looked ok especially at 500. Not exactly gfs but not far off.

 

It was better than 12z at that level, but just a bit too progressive.  The GFS still could be right.

[Clinch Leatherwood]

RAP is all wrapped up at 18 hours. 

 

Anyway, I like the idea of it snowing to some extent in eastern areas Tuesday night.  To what extent who knows....even the RGEM has some OES for a time on exit.

[CoastalWx]

Scott I like his numbers too.  IMO we already know where the Euro is going.  Check the 36h 12z Euro at 500mb vs the 48h 0z from the other night.  Now lay that over the 12z/18z/0z GFS runs.  The Euro and GFS are very similar with the diving energy what's different is some of these models still give some gusto to that lead s/w.  The GFS kills it.  That's either the GFS picking up on the trend prior to the other models or it's out to lunch and the Euro will be some version of the RGEM/NAM.

 

It's a mystery to me why this is so problematic at such short range.

 

Fast flow and one s/w after another will do it. I do admit this setup is a little more difficult then normal it seems for models to resolve.

[40/70 Benchmark]

Looks great at H5...famous last words.

 

I'm out.

[CoastalWx]

Scott I like his numbers too.  IMO we already know where the Euro is going.  Check the 36h 12z Euro at 500mb vs the 48h 0z from the other night.  Now lay that over the 12z/18z/0z GFS runs.  The Euro and GFS are very similar with the diving energy what's different is some of these models still give some gusto to that lead s/w.  The GFS kills it.  That's either the GFS picking up on the trend prior to the other models or it's out to lunch and the Euro will be some version of the RGEM/NAM.

 

It's a mystery to me why this is so problematic at such short range.

 

I'm not saying the trend is wrong...I'm just not sure of a 8-10 inch event or more that the GFS shows.

[eduggs]

Uncle looks decent. Hard to know what happens because you can't see qpf 24 to 30 but it looks robust.

Do you have the 500mb prog?  I don't really care about QPF.  Gonna overlay with the GFS on plymouth...

[wxsniss]

That was titled the 12z guidance, yo -

 

Nah... 

"00Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES"

And they refer to 21z SREF.

And this was just posted 11:20pm tnite.

And echo what several here are saying... slower/deeper GFS solution can't be ruled out.

 

 

[Ginx snewx]

Looks great at H5...famous last words.

I'm out.

you Jack

[Clinch Leatherwood]

Fast flow and one s/w after another will do it. I do admit this setup is a little more difficult then normal it seems for models to resolve.

The new Gfs and old euro are very close at 5h aside of that lead s/w which the Gfs dampens. It's either scoring a coup of has bad data on that feature for some reason.

[eduggs]

The UK is definitely not biting on the 2nd wave.  Nor is the Canadian. 

[weathafella]

Do you have the 500mb prog?  I don't really care about QPF.  Gonna overlay with the GFS on plymouth...

[CoastalWx]

The new Gfs and old euro are very close at 5h aside of that lead s/w which the Gfs dampens. It's either scoring a coup of has bad data on that feature for some reason.

 

Sometimes it's all or nothing, in other words it's not linear. If the lead s/w were to produce, it will help kick the baroclinic zone east and nothing is left. The euro op might have been depicting that at 12z. The GFS destroys the forst s/w and not the second one can act on the thermal ribbon and even enhance it. 

[eduggs]

I thought uk looked ok especially at 500. Not exactly gfs but not far off.

I overlayed 500mb and they are pretty different over SNE at 36hrs... which is strange for such a short term prog.  The UK looks more similar to pre 18z GFS runs.

[CoastalWx]

GEFS are biting.

[Clinch Leatherwood]

Sometimes it's all or nothing, in other words it's not linear. If the lead s/w were to produce, it will help kick the baroclinic zone east and nothing is left. The euro op might have been depicting that at 12z. The GFS destroys the forst s/w and not the second one can act on the thermal ribbon and even enhance it.

I guess the real question is:

How did the Gfs pick up the destruction of that feature before the others or...why did it destroy a relevant feature in error.

Euro has been off its game but it should at least come towards this solution to make it seem more likely.

[CoastalWx]

GEFS certainly side with the op.

[SouthCoastMA]

GEFS are biting.

Remember that storm in early January of last year that the GFS and GEFS blew up as a tucked in coastal 24-36 hours out? We still ended up getting a decent storm in se mass..but overall the GFS and the agreeable GEFS were out to lunch. Hopefully this isn't a repeat.