798  
FXUS10 KWNH 050524  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
123 AM EDT FRI JUN 05 2020  
 
VALID JUN 05/0000 UTC THRU JUN 08/1200 UTC  
 
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z INITIAL MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE  
 
...AMPLIFYING WAVE SHIFTING EAST ACROSS ONTARIO THROUGH TONIGHT  
AND NORTHERN NEW ENGLAND SATURDAY NIGHT...  
 
PREFERENCE: BLEND OF 12Z ECMWF/00Z NAM WITH SOME 00Z GFS/12Z UKMET  
CONFIDENCE: AVERAGE  
 
GOOD AGREEMENT AMONG GLOBAL GUIDANCE WITH THIS TROUGH AMPLIFYING  
AS IT SHIFTS EAST ACROSS THE NORTHEASTERN CONUS THIS WEEKEND. THE  
00Z GFS DEPICTS ITS TYPICAL TOO PROGRESSIVE BIAS BY SUNDAY/DAY 3,  
BUT THAT IS AS THE MID-LEVEL TROUGH AXIS IS SHIFTING OFF MAINE.  
THE MAIN OUTLIER IS THE 12Z CMC WHICH IS MUCH LESS AMPLIFIED WITH  
THE TROUGH OVER THE NORTHEAST. QPF FROM THE 12Z ECMWF/00Z NAM ARE  
QUITE SIMILAR FOR DAY 2 AND ARE PREFERRED. THE GFS QPF IS A BIT  
PROGRESSIVE FOR DAY 2, BUT INCLUSION OF IT AND THE 12Z UKMET ARE  
REASONABLE AT LOWER WEIGHTS.  
 
...INITIAL CUT-OFF LOW OFFSHORE SOUTHERN CALIFORNIA, MOVING  
ONSHORE TONIGHT, INTO GREAT BASIN SATURDAY, THE WYOMING ROCKIES  
SATURDAY NIGHT, AND THE NORTHERN PLAINS SUNDAY.  
 
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
A CUT OFF UPPER LOW WILL ONSHORE INTO SOUTHERN CALIFORNIA THIS  
EVENING. THE LOW OPENS UP AS IT MOVES INLAND WITHIN CONFLUENT FLOW  
AND BECOMES AN OPEN WAVE AND DEAMPLIFIES AS IT MOVES NORTH ACROSS  
THE GREAT BASIN SATURDAY. THE SHORTWAVE ENERGY MERGES WITH THE  
NORTHERN STREAM CLOSED LOW OVER THE PACIFIC NORTHWEST, WITH THE  
MODELS SHOWING A 700-500 MB WAVE AND SFC FLOW DEVELOPING IN MT  
LATE SATURDAY, WITH THE SFC LOW CROSSING INTO CANADA BY 12Z  
SUNDAY. EVEN THE SFC LOW DEVELOPING IN ID AND MOVING INTO MT SAT  
HAS GOOD CLUSTERING AMONG GLOBAL GUIDANCE. THE GOOD CLUSTERING  
SUPPORTS A MODEL BLEND TO MITIGATE MINOR TIMING AND LOCATION  
DIFFERENCES.  
 
...CLOSED LOW OFF BRITISH COLUMBIA DRIFTING SOUTH THROUGH FRIDAY  
NIGHT AND THEN OFF WASHINGTON/OREGON SATURDAY, MOVING EAST AND  
ONSHORE SATURDAY NIGHT-SUNDAY...  
 
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
EXCELLENT GLOBAL DETERMINISTIC CLUSTERING WITH THE CLOSED 500 MB  
LOW MOVING SOUTH OFFSHORE FROM BRITISH COLUMBIA FRIDAY, THEN OFF  
WA/OR SATURDAY, THEN MOVING THE LOW ONSHORE  
SATURDAY NIGHT, AND INTO THE NORTHERN ROCKIES SUNDAY. THERE IS  
BETTER THAN USUAL CLUSTERING AMONG THESE MODELS AND THEIR  
RESPECTIVE ENSEMBLE MEANS.  
 
   
..CRISTOBAL  
 
PREFERENCE: 03Z NHC ADVISORY  
CONFIDENCE: REFER TO NHC PRODUCTS  
 
THE OFFICIAL TRACK FOR T.D. CRISTOBAL IS A BIT OF COMPROMISE  
BETWEEN GLOBAL GUIDANCE, AVOIDING THE FASTER AND FARTHER EAST GFS  
THROUGH DAY 2. THE 12Z ECMWF AND 00Z NAM TRACKS A LITTLE SLOWER  
AND FARTHER WEST WITH THE 00Z CMC/UKMET A LITTLE FASTER AND ON THE  
EAST SIDE. MOST GUIDANCE SHIFTS WEST ON DAY 3 NEAR THE CENTRAL  
GULF COAST WITH THE NHC TRACK ON THE EAST SIDE OF THE GLOBAL  
DETERMINISTICS BY SUNDAY NIGHT.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
JACKSON  
 
 
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