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PHL Jan 11-12 Miller B Thread


am19psu

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DONT SHOOT THE MESSENGER, but I heard that the 12ZNAM had the infamous "initialization errors"

MODEL INITIALIZATION ERRORS ARE INDICATED UNDER THE RELEVANT

...SYSTEM HEADING.

..ERN CONUS/WRN ATLC EVOLUTION TUE ONWARD

WITH THE WAVE OFF THE SERN COAST THE NAM SFC ANALYSIS IS ABOUT 2

MB WEAKER THAN OBSERVED... AND MAY ALSO BE A LITTLE SSE OF THE

OBSERVED POSN. DEPENDING ON THE FCST HR THE NAM MID LVL SYSTEM IS

IN THE MIDDLE OR SLOWER HALF OF THE GUIDANCE SPREAD. THE SFC LOW

ALONG THE EAST COAST IS GENERALLY IN THE WRN THIRD OF THE

ENVELOPE. FROM TUE INTO WED THE PAST 24 HRS OF NAM RUNS SHOW

GRADUALLY FASTER TREND WITH LEADING MID LVL HGT FALLS PROGRESSING

FROM THE MID MS VLY INTO THE MID ATLC/NEW ENGLAND. THIS TREND

DIMINISHES BY F36 LATE WED. THE NAM COMPARES WELL TO OTHER WELL

CLUSTERED GUIDANCE WITH WEAKENING SFC LOW PRESSURE TO THE W OF THE

APLCHNS.

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DONT SHOOT THE MESSENGER, but I heard that the 12ZNAM had the infamous "initialization errors"

MODEL INITIALIZATION ERRORS ARE INDICATED UNDER THE RELEVANT

...SYSTEM HEADING.

..ERN CONUS/WRN ATLC EVOLUTION TUE ONWARD

WITH THE WAVE OFF THE SERN COAST THE NAM SFC ANALYSIS IS ABOUT 2

MB WEAKER THAN OBSERVED... AND MAY ALSO BE A LITTLE SSE OF THE

OBSERVED POSN. DEPENDING ON THE FCST HR THE NAM MID LVL SYSTEM IS

IN THE MIDDLE OR SLOWER HALF OF THE GUIDANCE SPREAD. THE SFC LOW

ALONG THE EAST COAST IS GENERALLY IN THE WRN THIRD OF THE

ENVELOPE. FROM TUE INTO WED THE PAST 24 HRS OF NAM RUNS SHOW

GRADUALLY FASTER TREND WITH LEADING MID LVL HGT FALLS PROGRESSING

FROM THE MID MS VLY INTO THE MID ATLC/NEW ENGLAND. THIS TREND

DIMINISHES BY F36 LATE WED. THE NAM COMPARES WELL TO OTHER WELL

CLUSTERED GUIDANCE WITH WEAKENING SFC LOW PRESSURE TO THE W OF THE

APLCHNS.

I think having a weaker pressure than reality and being SSE than reality, might be a "positive" initialization error. But I could be wrong.

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I think having a weaker pressure than reality and being SSE than reality, might be a "positive" initialization error. But I could be wrong.

It's an error in our favor, basically indicating that they feel the the preicp shield should have been about the same as 06z given the placement of the low.

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lol.... another "initialization error" this time the 12z GFS.... again, in our favor...

OFF THE MODEL INITIALIZATION AT 12Z, THE GFS APPEARS TOO FLAT WITH

THE SERN TROF AT 500MB AND A FARTHER OFFSHORE WHILE INTERNALLY

LOGICAL, MAY BE TOO EAST. THE WALLOPS 1C WARMER TEMPS AT 850MB

ARE NOT EXTENDING THAT FAR INLAND AS APG AND IAD 850MB TEMPS ARE

AT OR BELOW -4C AND MODEL INITIALIZATION IS TOO WARM THERE. SO NO BIG

PTYPE CHANGES WITH THIS UPDATE.

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lol.... another "initialization error" this time the 12z GFS.... again, in our favor...

OFF THE MODEL INITIALIZATION AT 12Z, THE GFS APPEARS TOO FLAT WITH

THE SERN TROF AT 500MB AND A FARTHER OFFSHORE WHILE INTERNALLY

LOGICAL, MAY BE TOO EAST. THE WALLOPS 1C WARMER TEMPS AT 850MB

ARE NOT EXTENDING THAT FAR INLAND AS APG AND IAD 850MB TEMPS ARE

AT OR BELOW -4C AND MODEL INITIALIZATION IS TOO WARM THERE. SO NO BIG

PTYPE CHANGES WITH THIS UPDATE.

Even with the error, the GFS wasn't THAT dry. Light snow lasts a bit longer, and it's still .25-.5.

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ETA looks epic! The final trending seems to indicate a shift wwd that would favor PHL and and NYC and even maybe just maybe further towards the A in ABE!!

I keep on dreaming of the white fluff, that beautiful white fluffy stuff. What would a crack addict say if he didn't know what snow was, and stepped outside tomorrow?

Cheers!

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You do have to be a little careful though; TOO Much trending west means tighter gradients and the possibility of the S/R line to shift further inland as well.

I do not think anyone really is going to have to worry about precipitation problems with a further west track. The low will be deepening very rapidly and this will cause the height lines to crash which is basically what all guidance in suggesting...

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ERN CONUS/WRN ATLC EVOLUTION TUE ONWARD...PREFERENCE: NAM/00Z ECMWF/09Z SREF MEAN COMPROMISE WITH SOMEINPUT FROM LATEST RUC RUNSWITH THE WAVE OFF THE SERN COAST THE NAM/GFS SFC ANALYSES AREABOUT 2 MB WEAKER THAN OBSERVED. BASED ON BOUNDARY LAYER WINDANALYSES... THE NAM MAY BE A LITTLE SSE OF THE OBSERVED SFC LOWPOSN AND TO A GREATER EXTENT THE GFS APPEARS TO BE INITIALIZED TOOFAR EWD. CONTINUING FROM INITIALIZATION TIME THE GFS REMAINS EWDOF THE NAM FOR THE DURATION OF TIME THAT THE SYSTEM AFFECTS THEEAST COAST. THE 09Z SREF MEAN AND 00Z ECMWF FCSTS VALID AT 12ZVERIFY CLOSEST TO OBSERVED AMONG RECENT GUIDANCE AND THE 12ZCANADIAN REG GEM OFFERS REASONABLE SUPPORT FOR THE NAM SCENARIO. 14Z-15Z RUC RUNS MAY BE A LITTLE WEAK BUT DO OFFER A TRACK WWD OFTHE GFS. AFOREMENTIONED CONSIDERATIONS RECOMMEND A COMPROMISEAMONG THE NAM/00Z ECMWF/09Z SREF MEAN WITH SOME IDEAS FROM LATESTRUC RUNS ALSO LIKELY PROVING TO BE HELPFUL. THE COMPROMISE OF THESREF MEAN/ECMWF WITH THE NAM ACCOUNTS FOR THE FACT THAT THE NAMLEANS TO THE SLOWER SIDE OF THE NON-GFS GUIDANCE SPREAD DURING WEDINTO WED NIGHT AND SOMETIMES HAS SLOW BIASES....MODEL TREND GRAPHICS AT WWW.HPC.NCEP.NOAA.GOV/HTML2.SHTML......500 MB FORECASTS ATWWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...RAUSCH

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ERN CONUS/WRN ATLC EVOLUTION TUE ONWARD...PREFERENCE: NAM/00Z ECMWF/09Z SREF MEAN COMPROMISE WITH SOMEINPUT FROM LATEST RUC RUNSWITH THE WAVE OFF THE SERN COAST THE NAM/GFS SFC ANALYSES AREABOUT 2 MB WEAKER THAN OBSERVED. BASED ON BOUNDARY LAYER WINDANALYSES... THE NAM MAY BE A LITTLE SSE OF THE OBSERVED SFC LOWPOSN AND TO A GREATER EXTENT THE GFS APPEARS TO BE INITIALIZED TOOFAR EWD. CONTINUING FROM INITIALIZATION TIME THE GFS REMAINS EWDOF THE NAM FOR THE DURATION OF TIME THAT THE SYSTEM AFFECTS THEEAST COAST. THE 09Z SREF MEAN AND 00Z ECMWF FCSTS VALID AT 12ZVERIFY CLOSEST TO OBSERVED AMONG RECENT GUIDANCE AND THE 12ZCANADIAN REG GEM OFFERS REASONABLE SUPPORT FOR THE NAM SCENARIO. 14Z-15Z RUC RUNS MAY BE A LITTLE WEAK BUT DO OFFER A TRACK WWD OFTHE GFS. AFOREMENTIONED CONSIDERATIONS RECOMMEND A COMPROMISEAMONG THE NAM/00Z ECMWF/09Z SREF MEAN WITH SOME IDEAS FROM LATESTRUC RUNS ALSO LIKELY PROVING TO BE HELPFUL. THE COMPROMISE OF THESREF MEAN/ECMWF WITH THE NAM ACCOUNTS FOR THE FACT THAT THE NAMLEANS TO THE SLOWER SIDE OF THE NON-GFS GUIDANCE SPREAD DURING WEDINTO WED NIGHT AND SOMETIMES HAS SLOW BIASES....MODEL TREND GRAPHICS AT WWW.HPC.NCEP.NOAA.GOV/HTML2.SHTML......500 MB FORECASTS ATWWW.HPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML...RAUSCH

Basically they are saying that the models are wrong about the low placement at initialization and the strength, and that the ECMFW is the closest but may still have been too far east, this bodes well for PHL and N and W.

We will see how the nowcast develops further, seeing as NOAA is already saying we have to watch bc it could be NAMlike or even further west.

Don't despair, we may be in for a surprise or two!

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Good, I'm an ABE guy too. I work in Newark though. So I straddle both threads.

ETA looks epic! The final trending seems to indicate a shift wwd that would favor PHL and and NYC and even maybe just maybe further towards the A in ABE!!

I keep on dreaming of the white fluff, that beautiful white fluffy stuff. What would a crack addict say if he didn't know what snow was, and stepped outside tomorrow?

Cheers!

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