594  
FXUS10 KWNH 081835  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
134 PM EST FRI DEC 08 2017  
 
VALID DEC 08/1200 UTC THRU DEC 12/0000 UTC  
 
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL PREFERENCES WITH CONFIDENCE INTERVALS  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
ERRORS WITHIN THE GFS/NAM INITIALIZATIONS DO NOT SEEM TO DEGRADE  
THEIR SHORT RANGE FORECASTS.  
 
 
SYSTEM SIDESWIPING THE PACIFIC NORTHWEST MONDAY AFTERNOON  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: UKMET; CONFIDENCE SLIGHTLY ABOVE AVERAGE  
 
DIFFERENCES WITH THIS SYSTEM ARE BECOMING MUCH LESS SIGNIFICANT.  
THE 12Z ECMWF/ITS OLD ENSEMBLE MEAN ARE THE QUICKEST WHILE THE  
NCEP GUIDANCE IS THE QUICKEST. THE 12Z UKMET MAKES FOR A NICE  
INTERMEDIATE SOLUTION, WHICH IS PREFERRED WITH SLIGHTLY ABOVE  
AVERAGE CONFIDENCE.  
 
SHORTWAVE DROPPING INTO THE NORTHERN PLAINS SUNDAY NIGHT  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: ECMWF/UKMET/GFS BLEND; CONFIDENCE AVERAGE  
 
THE GUIDANCE SHOWS SOME CONVERGENCE ALOFT AND AT THE SURFACE IN  
THEIR 12Z RUNS. THE 12Z NAM IS THE QUICKEST WHILE THE 12Z  
CANADIAN IS THE DEEPEST. THE GUIDANCE OVERALL REMAINS WELL WITHIN  
THE BROAD 00Z GLOBAL ENSEMBLE SPREAD RESPECTIVELY. A COMPROMISE  
OF THE 12Z ECMWF, 12Z UKMET, AND 12Z GFS IS ADVISED TO HELP DEAL  
WITH MODEL ISSUES AND TO ACCOUNT FOR EXPECTED PATTERN WITH  
CONFIDENCE NO BETTER THAN AVERAGE CONSIDERING FAIRLY POOR  
RUN-TO-RUN VARIABILITY.  
 
UPPER LOW MOVING INTO NORTHERN BAJA CA MONDAY  
PHASING SHORTWAVES ACROSS THE MID-ATLANTIC LATE SATURDAY  
SURFACE LOW MOVING OFFSHORE THE EAST COAST  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
ANY DIFFERENCES SEEN IN THE GUIDANCE WITH THESE SYSTEMS ARE WITHIN  
THE NOISE LEVEL. A COMPROMISE OF THE 00Z CANADIAN, 00Z UKMET, 00Z  
ECMWF, 12Z GFS, AND 12Z NAM IS ADVISED WITH ABOVE AVERAGE  
CONFIDENCE. FOR PRECIPITATION/SNOW AMOUNT FORECAST THOUGHTS, SEE  
OUR QUANTITATIVE PRECIPITATION FORECAST (QPFPFD) AND PROBABILISTIC  
HEAVY SNOW AND ICING DISCUSSIONS (QPFHSD).  
 
THE NEXT COMPLETE MODEL DIAGNOSTIC DISCUSSION (PMDHMD) WILL BE  
ISSUED BY 1645Z SATURDAY.  
 
ROTH  
 
PREVIOUS MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
PREVIOUS 500 MB FORECASTS AT  
WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page