699  
FXUS10 KWNH 271617  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
1116 AM EST MON NOV 27 2017  
 
VALID NOV 27/1200 UTC THRU DEC 01/0000 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z NAM/GFS EVALUATION WITH PRELIMINARY MODEL PREFERENCES  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
NAM/GFS INITIALIZATION ERRORS DO NOT SEEM TO DEGRADE THEIR SHORT  
RANGE FORECASTS.  
 
CLOSED LOW DROPPING OFFSHORE CA/BAJA CALIFORNIA  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: NON-NAM BLEND; CONFIDENCE ABOVE AVE  
 
THE 12Z NAM KEEPS THIS SYSTEM WEAK AND PROGRESSIVE WHILE THE REST  
OF THE GUIDANCE SHOWS IT DROPPING SOUTH OFFSHORE CA AND BAJA  
CALIFORNIA. AS THE UPSTREAM RIDGE IS AMPLIFYING, THE MORE DUG  
IN/ANTICYCLONIC WAVE BREAKING EVENT APPEARS MORE LIKELY. A  
NON-NAM COMPROMISE IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.  
 
UPPER LOW/SHORTWAVE MOVING THROUGH SOUTHERN U.S. MON-THU  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GFS/ECMWF/UKMET BLEND; CONFIDENCE ABOVE AVE  
 
THE 00Z CANADIAN WAS THE WEAKEST WITH THIS SYSTEM WHILE THE 12Z  
NAM BECAME THE STRONGEST FROM WEDNESDAY ONWARD -- THE USUAL NAM  
BIAS. A COMPROMISE OF THE INTERMEDIATE 12Z GFS, 00Z ECMWF, AND  
00Z UKMET IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.  
 
SHORTWAVE STREAKING THROUGH THE NORTHERN TIER TUE-THU  
SHORTWAVE STREAKING THROUGH THE NORTHERN TIER MON-WED  
MID-LEVEL LOW OVER FL THROUGH TUESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
THE GUIDANCE SHOWS GOOD AGREEMENT WITH THESE SYSTEMS. A  
COMPROMISE OF THE 00Z CANADIAN, 00Z UKMET, 00Z ECMWF, 12Z GFS, AND  
12Z NAM IS PREFERRED WITH ABOVE AVERAGE CONFIDENCE.  
 
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