737  
FXUS10 KWNH 220705  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
305 AM EDT TUE OCT 22 2019  
 
VALID OCT 22/0000 UTC THRU OCT 25/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
 
CENTRAL U.S. CYCLONE; SECONDARY LOW FROM CAROLINAS TO NEW ENGLAND  
TODAY-WED.  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: GENERAL MODEL BLEND  
CONFIDENCE: ABOVE AVERAGE  
 
OCCLUDED LOW NEAR MSP WILL CONTINUE TO LIFT NORTH/NORTHEAST OVER  
THE NEXT 48 HOURS INTO WESTERN ONTARIO AND GRADUALLY BECOME  
STACKED WITH THE UPPER LEVEL LOW. ITS STRENGTH WILL MORE OR LESS  
MAINTAIN ITSELF THE NEXT 2 DAYS THEN SOME GRADUAL WEAKENING IS  
EXPECTED. A SECONDARY LOW PRESSURE WILL FORM ACROSS THE SOUTHERN  
APPALACHIANS AND THEN LIFT ALONG THE EASTERN U.S. COASTLINE.  
OVERALL, WITH BOTH OF THESE FEATURES THERE IS VERY GOOD AGREEMENT  
WITH ABOVE AVERAGE FORECAST CONFIDENCE IN THE PLACEMENT AND  
STRENGTH SUCH THAT A GENERAL MODEL BLEND IS SUFFICIENT.  
 
STRONGER SHORTWAVE DROPPING THROUGH ROCKIES INTO THE SOUTHERN  
PLAINS EARLY TO MID WEEK  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: ECENS MEAN (WITH SOME CMC/UKMET WEIGHT)  
CONFIDENCE: BELOW AVERAGE  
 
07Z UPDATE: WITH THE REST OF THE 00Z GUIDANCE NOW AVAILABLE, THERE  
WAS NOT MUCH, IF ANY, TREND TOWARD BETTER AGREEMENT ON THE  
EVOLUTION OF THE MID/UPPER LEVEL SHORTWAVE ENERGY OVER THE  
SOUTHWEST US AND SOUTHERN PLAINS LATE IN THE WEEK. THE 00Z  
ECMWF/CMC IN FACT TRENDED DEEPER, DIGGING THE LOW WELL INTO NEW  
MEXICO. THE UKMET IS CLOSED OFF AS WELL, BUT NOT AS FAR (TX  
PANHANDLE AT 25.12Z). THIS IS IN STARK CONTRAST TO THE NCEP  
GUIDANCE (GFS/NAM) WHICH IS FLATTER AND MORE PROGRESSIVE. GIVEN  
THE HIGHER THAN USUAL SPREAD AT 3 DAYS, THE WPC PREFERENCE IS  
STILL FOR A SOLUTION SIMILAR TO THE ECENS MEAN, WHICH DIGS THE LOW  
WELL INTO THE SOUTHWEST US, BUT ISN'T AS AGRESSIVE AS THE  
DETERMINISTIC EC. FORECAST CONFIDENCE IS BELOW AVERAGE.  
 
---PREVIOUS DISCUSSION---  
SHORTWAVE ENERGY DROPPING SOUTHWARD THROUGH THE CANADIAN ROCKIES  
AND BUILDING HEIGHTS OVER THE EASTERN PACIFIC WILL LEAD TO AN  
AMPLIFIED PATTERN BY LATER IN THE WEEK. STRENGTHENING SOUTHERN  
STREAM ENERGY WILL DEVELOP ACROSS THE SOUTHWEST INTO WEST TEXAS.  
THE ECMWF REMAINS THE MOST AMPLIFIED, CLOSING OFF THE MID/UPPER  
LEVEL FEATURE THOUGH THERE IS SOME SUPPORT WITH THE CMC AS WELL.  
LOOKING AT THE LAST SEVERAL MODEL RUNS, THE GFS HAS BEEN SLOWLY  
TRENDING TOWARD THE ECMWF SOLUTION, THOUGH NOT AS AGGRESSIVE WHILE  
SUBSEQUENT RUNS OF THE ECMWF HAVE BEEN FAIRLY CONSISTENT.  
 
THE WPC PREFERENCE REMAINS FOR A HEAVY WEIGHT TOWARD THE NON-NCEP  
GUIDANCE BUT NOT AS AMPLIFIED AS THE DETERMINISTIC ECMWF SUGGESTS,  
WITH MOST OF THE WEIGHT TOWARD THE ECENS MEAN WHICH IS A GOOD  
COMPROMISE AT THIS POINT UNTIL FORECAST CONFIDENCE INCREASES AND  
MODEL SPREAD LOWERS.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
TAYLOR  
 

 
 
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