465  
FXUS10 KWNH 301915  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
315 PM EDT SAT MAY 30 2020  
 
VALID MAY 30/1200 UTC THRU JUN 03/0000 UTC  
 
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
12Z MODEL EVALUATION INCLUDING PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
UPPER LEVEL TROUGH AND COLD FRONT ACROSS THE EASTERN U.S.  
SATURDAY-MONDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH 00Z TUESDAY  
CONFIDENCE: ABOVE AVERAGE  
 
THROUGH 00Z TUESDAY - AS THE UPPER TROUGH MOVES EAST FROM GREAT  
LAKES/OHIO VALLEY THROUGH THE EASTERN U.S. - THE DETERMINISTIC  
MODEL RUNS AND ENSEMBLE MEANS ARE IN GENERALLY GOOD AGREEMENT WITH  
THE LARGER SCALE FEATURES.  
 
 
UPPER LEVEL LOW SLOWLY LIFTING FROM NORTHERN MEXICO INTO THE  
SOUTHERN PLAINS SATURDAY-TUESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: AVERAGE  
 
WHILE THERE ARE DIFFERENCE WITH RESPECT TO SOME OF ITS ASSOCIATED  
SMALLER SCALE FEATURES, (WHICH FALL BEYOND THE SCOPE OF THIS  
DISCUSSION), MODELS ARE IN GENERALLY GOOD AGREEMENT SHOWING A  
BROAD UPPER LOW LIFTING NORTH FROM NORTHERN MEXICO INTO WEST TEXAS  
ON MONDAY, BEFORE CONTINUING NORTHEAST INTO NORTHERN TEXAS AND  
OKLAHOMA ON TUESDAY.  
 
WEAKENING UPPER LOW LIFTING FROM NORTHERN CALIFORNIA THROUGH THE  
PACIFIC NORTHWEST SATURDAY AND SUNDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH 12Z TUESDAY,  
NON-UKMET BLEND 12Z TUESDAY-00Z WEDNESDAY  
CONFIDENCE: AVERAGE  
 
OVERALL, MODELS ARE IN GOOD AGREEMENT SHOWING AN UPPER LOW  
CURRENTLY CENTERED ALONG THE NORTHERN CALIFORNIA COAST  
TRANSITIONING TO AN OPEN WAVE AS IT LIFTS ACROSS OREGON AND  
WASHINGTON LATE SATURDAY AND SUNDAY. MODELS REMAIN IN GOOD  
AGREEMENT INTO EARLY MONDAY AS THE SYSTEM CONTINUES FARTHER  
NORTHEAST ACROSS THE CANADIAN ROCKIES INTO CENTRAL CANADA.  
SIGNIFICANT MODEL DIFFERENCES DO NOT EVOLVE UNTIL EARLY TUESDAY AS  
SYSTEM BEGINS TO MOVE SOUTH OF HUDSON BAY. AS THE SYSTEM BEGINS  
TO ROUND THE TOP OF THE UPPER RIDGE, THE UKMET BECOMES A NOTED  
OUTLIER - WITH A CLOSED SYSTEM DEVELOPING SOUTH OF HUDSON BAY.  
 
UPPER LEVEL TROUGH MOVING FROM THE PACIFIC NORTHWEST TO THE  
NORTHERN PLAINS AND UPPER MIDWEST MONDAY-TUESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND THROUGH 12Z MONDAY THEN,  
GFS/ECMWF COMPROMISE 12Z MONDAY-00Z WEDNESDAY  
CONFIDENCE: AVERAGE  
 
WITH RESPECT TO TIMING, THE MODELS ARE IN GENERALLY GOOD AGREEMENT  
THROUGH EARLY MONDAY AS THE SYSTEM MOVES EAST FROM THE EASTERN  
PACIFIC INTO THE PACIFIC NORTHWEST. HOWEVER, DIFFERENCES QUICKLY  
DEVELOP AS THE SYSTEM MOVES DOWNSTREAM, WITH THE UKMET, ECMWF AND  
THE 00Z EC ENSEMBLE MEAN BECOMING NOTABLY FASTER THAN THE NCEP  
GUIDANCE THROUGH THE NORTHERN ROCKIES INTO THE PLAINS AND UPPER  
MIDWEST. WHILE THE GFS IS STILL AMONG THE SLOWER SOLUTIONS, IT  
HAS TRENDED FASTER COMPARED TO ITS 00Z AND PREVIOUS 12Z SOLUTIONS.  
AND WHILE STILL FASTER THAN THE GFS, THE 12Z ECMWF IS SLOWER THAN  
ITS 00Z RUN - SUGGESTING THE TWO MODELS MAY BE MOVING TOWARD A  
CONSENSUS.  
 
CUTOFF LOW DEVELOPING WEST OF SOUTHERN CALIFORNIA AND NORTHERN  
BAJA MONDAY-TUESDAY  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: UKMET/ECMWF/00Z EC ENSEMBLE MEAN  
CONFIDENCE: AVERAGE  
 
ENERGY DROPPING SOUTHEAST ACROSS THE EASTERN PACIFIC IS EXPECTED  
TO DEVELOP A CLOSED LOW OFF OF THE SOUTHERN CALIFORNIA AND  
NORTHERN BAJA COASTS EARLY NEXT WEEK. LATEST GUIDANCE SHOWS SOME  
DIFFERENCES WITH RESPECT TO THE POSITION OF THE LOW'S CENTER, WITH  
THE NCEP GUIDANCE GENERALLY EAST OF THE UKMET, ECMWF AND THE 00Z  
EC ENSEMBLE MEAN. TRENDS IN THE GFS SUPPORT LEANING TOWARD THE  
UKMET, ECMWF AND 00Z EC ENSEMBLE MEAN.  
 
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML  
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
PEREIRA  
 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab HPC Page
Main Text Page