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12Z Model runs Christmas Eve 2010


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From BOX AFD:

"WE WANTED TO NOTE THAT WE HAVE RECEIVED MESSAGES FROM

HPC ABOUT INITIALIZATION PROBLEMS ON BOTH THE NAM AND GFS RUNS THIS

MORNING. "

i guess it was after 10:16?

MODEL DIAGNOSTIC DISCUSSION

NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD

1016 AM EST FRI DEC 24 2010

VALID DEC 24/1200 UTC THRU DEC 28/0000 UTC

...SEE NOUS42 KWNO ADMNFD FOR THE STATUS OF THE UPPER AIR

INGEST...

12Z NAM EVALUATION

INITIALIZATION ERRORS DO NOT APPEAR TO SIGNIFICANTLY IMPACT ITS

SOLUTION.

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Ask yourselves this as we wait for the rest of the suite:

How many times has the higher res NAM/RGEM been east/weaker than the GFS at this stage? I cannot remember one time. Either the RGEM/NAM are suffering from a significant issue or the GFS is, it's staggering at this range that the roles are reversed. One thought is the situation is so extreme, and there is so much energy that the higher res models so far are being tripped up by meso features and are displacing the low further east in a feedback loop.

i think you hit the nail on the head there... i see a BIG feadback loop in the 12Z NAM... the maximum vorticity jumps north from the mid atl. coast to NE of the benchmark in 6 hours... with a storm wrapped that tightly, that should NOT happen.

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HPC and NCEP sites don't look too serious with initialization problems.

HPC site- model diagnostic discussion says initialization errors doesn't affect NAM.

NCEP status

000

NOUS42 KWNO 241340

ADMNFD

SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE

NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD

1337Z FRI DEC 24 2010

12Z NCEP MODEL PRODUCTION IS ON TIME..

12Z NAM RAOB RECAP...

BRW/70026 - 10142

GUM/91212 - 10142

NCC/78988 - 10142

YNN/78073 - 10142

ZED/71126 - MISSING TTAA/BB

ASY/70414 - 10145

KCR/78384 - PURGED ALL HGTS AND TEMPS

GYM/76256 - PURGED REPORT...TWIN REPORT

CRITICAL WEATHER DAY STATUS...

NCEP DOES NOT ANTICIPATE A CWD DURING THE NEXT 3 DAYS.

$$

Edit, add link for future reference...

http://www.nws.noaa.gov/view/validProds.php?prod=ADM&node=KWNO

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i guess it was after 10:16?

It's kind of common they don't catch GFS errors until the 12-1pm statement. Very typical.

It's impossible to say it effected anything. It's also impossible to say it hurt the favorable outcome, who's to say it wouldn't be a bigger GFS hit. I heard the same thing - that the NAM was not/less effected but how can that really be unless it was a data error?

Would be ironic if something had been happening for a bit here that was contributing to the model flops.

What a mess.

We will prob see the updated status by 1 as usual....most of the time it's about 1220

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INITIALIZATION ERRORS IN NUMEROUS DIAGNOSTIC

QUANTITIES...INCLUDING HEIGHT/VORTICITY FIELDS/RH...ARE EVIDENT IN

BOTH THE 12Z NAM/GFS WITH SMALL BUT LIKELY SIGNIFICANT SHORTWAVE

TROUGHS OVER SOUTH DAKOTA/NEBRASKA ALONG WITH

SASKATCHEWAN/MANITOBA...WITH THESE AREAS ALSO NOT PARTICULARLY

RESOLVED OR PREDICTED WELL BY THE 00Z ECMWF. THUS...THE SPECIFIC

PREDICTIONS BY ALL DETERMINISTIC GUIDANCE ARE IN QUESTION...WITH

THE RECOMMENDATION TO FOLLOW CONTINUITY...WITH THE FINAL OUTCOME

MOST BELIEVED TO LIE BETWEEN THE 06Z GFS AND 00Z ECMWF...WITH ALL

ENSEMBLE GUIDANCE INCLUDING THE SREF MEAN/GEFS MEAN/ECMWF ENSEMBLE

MEAN ALSO CONSIDERED USEFUL TO ADDRESS THE CONTINUED UNCERTAINTY.

THIS APPROACH DISREGARDS THE SUBSTANTIALLY DEEPER AND WESTWARD

SHIFT OF THE 12Z GFS REGARDING THE POWERFUL LOW TRACKING UP THE

EASTERN SEABOARD...AND TO A LESSER EXTENT THE 12Z NAM WHICH LIES

NEAR THE FAST EDGE OF THE GUIDANCE WITH THE DEVELOPING LOW.

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12Z NAM/GFS EVALUATION INCLUDING PRELIMINARY PREFERENCES

...SPLIT SHORTWAVE TROUGHS EXTENDING OVER THE PLAINS/MIDWEST...

...LOW PRESSURE FORMING ALONG THE EAST COAST THROUGH MONDAY...

PREFERENCE: EQUAL BLEND OF THE 06Z GFS/00Z ECMWF OR THE ENSEMBLE

MEANS

INITIALIZATION ERRORS IN NUMEROUS DIAGNOSTIC

QUANTITIES...INCLUDING HEIGHT/VORTICITY FIELDS/RH...ARE EVIDENT IN

BOTH THE 12Z NAM/GFS WITH SMALL BUT LIKELY SIGNIFICANT SHORTWAVE

TROUGHS OVER SOUTH DAKOTA/NEBRASKA ALONG WITH

SASKATCHEWAN/MANITOBA...WITH THESE AREAS ALSO NOT PARTICULARLY

RESOLVED OR PREDICTED WELL BY THE 00Z ECMWF. THUS...THE SPECIFIC

PREDICTIONS BY ALL DETERMINISTIC GUIDANCE ARE IN QUESTION...WITH

THE RECOMMENDATION TO FOLLOW CONTINUITY...WITH THE FINAL OUTCOME

MOST BELIEVED TO LIE BETWEEN THE 06Z GFS AND 00Z ECMWF...WITH ALL

ENSEMBLE GUIDANCE INCLUDING THE SREF MEAN/GEFS MEAN/ECMWF ENSEMBLE

MEAN ALSO CONSIDERED USEFUL TO ADDRESS THE CONTINUED UNCERTAINTY.

THIS APPROACH DISREGARDS THE SUBSTANTIALLY DEEPER AND WESTWARD

SHIFT OF THE 12Z GFS REGARDING THE POWERFUL LOW TRACKING UP THE

EASTERN SEABOARD...AND TO A LESSER EXTENT THE 12Z NAM WHICH LIES

NEAR THE FAST EDGE OF THE GUIDANCE WITH THE DEVELOPING LOW.

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INITIALIZATION ERRORS IN NUMEROUS DIAGNOSTIC

QUANTITIES...INCLUDING HEIGHT/VORTICITY FIELDS/RH...ARE EVIDENT IN

BOTH THE 12Z NAM/GFS WITH SMALL BUT LIKELY SIGNIFICANT SHORTWAVE

TROUGHS OVER SOUTH DAKOTA/NEBRASKA ALONG WITH

SASKATCHEWAN/MANITOBA...WITH THESE AREAS ALSO NOT PARTICULARLY

RESOLVED OR PREDICTED WELL BY THE 00Z ECMWF. THUS...THE SPECIFIC

PREDICTIONS BY ALL DETERMINISTIC GUIDANCE ARE IN QUESTION...WITH

THE RECOMMENDATION TO FOLLOW CONTINUITY.

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what i gather from the HPC is air on the side of caution... they said those errors MIGHT have impacted the forecast... they did not say they definitively did... I'm not going to pass any judgement until the 00Z runs tonight.

based on the 18Z ruc compared to the 6 hr depiction on the 12Z GFS if anything i#d say it was too weak with the norhtern shortwave and too fart NE with the TX shortwave.

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what i gather from the HPC is air on the side of caution... they said those errors MIGHT have impacted the forecast... they did not say they definitively did... I'm not going to pass any judgement until the 00Z runs tonight.

based on the 18Z ruc compared to the 6 hr depiction on the 12Z GFS if anything i#d say it was too weak with the norhtern shortwave and too fart NE with the TX shortwave.

Do you mean to far Ne?

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People need to relax and cool it with the angry posts - this solution was a huge shift from all recent model guidance. Data initialization errors or not it seemed like a major long shot.

yeah, but the GFS trends were still West even before the 12Z run. It just needed a touch more of a pull from that 500 MB low , and it got it.

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Aren't the ensembles run on slightly different initialization conditions to see the results of those changes? If so why do those also show a big hit then?

They're run with certain artificial perturbations to the observed initial conditions. So if the observed data is significantly off, those perturbations will still cluster around the faulty data.

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