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FXUS10 KWNH 241607
PMDHMD

MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1207 PM EDT FRI OCT 24 2014

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

...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...


12Z MODEL EVALUATION WITH PREFERENCES

NAM/GFS INITIALIZATION ERRORS DO NOT APPEAR TO DEGRADE THEIR SHORT
RANGE FORECASTS.


DEEP CYCLONE MOVING INTO THE PACIFIC NORTHWEST SATURDAY
MID-UPPER TROUGH MOVING ACROSS THE INTERMOUNTAIN WEST SUNDAY TO
CENTRAL/NORTHERN PLAINS MONDAY

PREFERENCE: 06Z GFS/00Z ECMWF COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 00Z ECMWF/00Z UKMET/06Z GFS/12Z NAM CLUSTER WELL WITH THE
TRACK OF THE SFC LOW MOVING FROM THE PACIFIC JUST OFF THE OREGON
COAST AND INTO WA STATE...WITH MINOR TIMING DIFFERENCES.
THE LOW OCCLUDES IN SOUTHWEST CANADA AND A TRIPLE POINT LOW FORMS
ON THE LEE SIDE OF THE ROCKIES IN THE NORTHERN PLAINS SUNDAY.  THE
12Z GFS MADE A SIGNIFICANT CHANGE TO SLOW DOWN THE LOW AS IT
REACHES THE COAST AND FALLS BEHIND THE OTHER MODELS WITH A FURTHER
WEST POSITION 06Z-12Z SUN.  THE 06Z GEFS MEAN AND OPERATIONAL GFS
CLUSTER BETTER WITH THE OTHER MODELS...SO CONFIDENCE IS LOW IN THE
12Z GFS ADJUSTMENT.

THE 00Z ECMWF/UKMET/12Z NAM IN THE NORTHERN PLAINS CLUSTER WELL
WITH THE LOW 00Z MON-12Z MON AS IT APPROACHES THE CANADIAN BORDER.


THE 00Z CANADIAN WAS A SLIGHTLY DEEP OUTLIER AT 500 MB ACROSS MT
EARLY MONDAY AND THE NORTHERN PLAINS MONDAY AFTERNOON, AND ITS
SURFACE SOLUTION IS FURTHER SOUTH THAN THE OTHER GUIDANCE ACROSS
THE NORTHERN PLAINS.  LESS WEIGHTING IS GIVEN THE 00Z CANADIAN
GIVEN THE THE MAJORITY CLUSTER SFC LOW FURTHER NORTH ALONG THE
US/CANADIAN BORDER.


...CYCLONE DEVELOPING OVER NORTHERN NEW ENGLAND INTO ATLANTIC
CANADA...

PREFERENCE: MODEL COMPROMISE
CONFIDENCE: ABOVE AVERAGE

THE 12Z GFS TRENDED TO A MORE SOUTHEAST DEVELOPMENT LOCATION WITH
BETTER OVERLAP NOW WITH ITS SOLUTIONS AND THE 09Z SREF MEAN/00Z
ECMWF/00Z UKMET.  AS A RESULT OF AN IMPROVED CLUSTERING OF
SOLUTIONS...A CONSENSUS OF THESE SOLUTIONS IS RECOMMENDED.
THE 12Z NAM UIS JUST A TAD SOUTH OF THE PRIMARY CLUSTER AS THE LOW
CROSSES NORTHERN MAINE.

...CYCLONE MOVING EAST TOWARDS VANCOUVER ISLAND MON-MONDAY
EVENING...

PREFERENCE: 06Z GFS/09Z SREF MEAN/12Z NAM
CONFIDENCE: AVERAGE

THE MODELS ARE IN AGREEMENT ON THE CLOSED LOW DEVELOPING IN THE
NORTH EAST PACIFIC AND MOVING EAST NORTHEAST IN THE DIRECTION OF
VANCOUVER ISLAND LATE MON-MON EVENING.
THERE ARE TYPICAL TIMING/TRACK DIFFERENCES WITH THE 00Z ECMWF ON
THE FASTER/SOUTHEASTERN EDGE OF THE GUIDANCE SUITE....WITH THE
ECMWF ENSEMBLE MEAN A FEW HOURS SLOWER AND IN EXCELLENT AGREEMENT
WITH THE 06Z GFS/06Z GEFS MEAN/09Z SREF MEAN/12Z NAM ON THE
CYCLONE TIMING.


...MODEL TREND GRAPHICS AT
www.wpc.ncep.noaa.gov/html/model2.shtml...
...500 MB FORECASTS AT
www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml...

PETERSEN

$$





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