685  
FXUS10 KWNH 160633  
PMDHMD  
 
MODEL DIAGNOSTIC DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
232 AM EDT FRI AUG 16 2019  
 
VALID AUG 16/0000 UTC THRU AUG 19/1200 UTC  
 
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR  
INGEST...  
 
00Z MODEL EVALUATION...INCLUDING PREFERENCES AND CONFIDENCE  
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
   
..OVERALL PATTERN ACROSS THE CONUS
 
 
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~  
PREFERENCE: BLEND OF THE 00Z GFS/ECMWF  
CONFIDENCE: SLIGHTLY ABOVE AVERAGE  
 
THE UPPER-LEVEL PATTERN STARTS OFF WITH MODEST RIDGING ACROSS THE  
SOUTHWEST AND BROAD NORTHWESTERLY FLOW TO ITS NORTH AND DOWNSTREAM  
ACROSS THE NORTHERN PLAINS AND MIDWEST, LEADING TO BROAD TROUGHING  
ACROSS THE EASTERN HALF OF THE NATION. THE RIDGE OVER THE  
SOUTHWEST WILL CONTINUE TO WEEKEND ON FRIDAY AND SATURDAY AS  
STRONGER NORTHERN STREAM TROUGHING DIGS SOUTH THROUGH SOUTHWEST TO  
SOUTH-CENTRAL CANADA AND ACROSS THE NORTHERN ROCKIES AND NORTHERN  
PLAINS REGION. ON SUNDAY, THE TROUGHING WILL PIVOT ACROSS THE  
MIDWEST AND GREAT LAKES REGION, BUT WILL BEGIN TO RETREAT A BIT  
FARTHER NORTH WHICH WILL ALLOW AN ELONGATED SUBTROPICAL RIDGE TO  
BE FOCUSES ACROSS THE CENTRAL AND SOUTHERN U.S. AND RATHER STRONG  
ZONAL FLOW FROM THE NORTHWEST TO THE NORTHEAST ASSOCIATED WITH THE  
WESTERLIES UP ACROSS THE NORTHERN TIER OF THE NATION.  
 
ANOMALOUS MOISTURE WILL REMAIN IN PLACE AHEAD OF A SLOW MOVING  
FRONT WHICH WILL EXTEND FROM THE MID-ATLANTIC REGION TO THE GULF  
COAST, WHILE IMPULSES IN NORTHWEST FLOW ALOFT KEEP THE CENTRAL  
PLAINS TO THE MIDWEST ACTIVE WITH MULTIPLE ROUNDS OF ORGANIZED  
CONVECTION. THERE IS BROAD AGREEMENT AMONG THE GLOBAL MODELS WITH  
THE SYNOPTIC SCALE FEATURES ACROSS THESE AREAS, BUT THE 00Z NAM IN  
GENERAL APPEARS TO BE A TAD TOO AMPLIFIED WITH ITS CONVECTIVELY  
ENHANCED VORT ENERGY CROSSING AREAS OF THE LOWER MO AND MIDDLE MS  
VALLEYS THROUGH FRIDAY AND SATURDAY.  
 
ACROSS THE SOUTHEAST AND EASTERN GULF COAST REGION, THE GUIDANCE  
CONTINUES TO HINT AT A WEAK AREA OF LOW  
PRESSURE DEVELOPING ALONG THE AFOREMENTIONED FRONT, AND THE  
GUIDANCE AGREES IN LIFTING A WEAK AREA OF LOW PRESSURE UP ALONG  
THE FRONT AND ACROSS THE SOUTHERN MID-ATLANTIC THROUGH FRIDAY  
NIGHT AND THEN OFFSHORE THE EAST COAST ON SATURDAY. A SECOND AREA  
OF LOW PRESSURE IS ALSO BEING FORECAST BY THE GUIDANCE TO EVOLVE  
NEAR THE COASTAL PLAIN OF THE CAROLINAS SUNDAY NIGHT AND MONDAY.  
THE 00Z UKMET IS A STRONGER OUTLIER WITH THIS SYSTEM WHICH ALSO  
CORRESPONDS TO A MUCH WETTER SOLUTION OVER SOUTHEAST NC.  
 
THE HEIGHT FALL EVOLUTION ACROSS SOUTHWEST TO SOUTH-CENTRAL CANADA  
IS BETTER RESOLVED IT WOULD APPEAR AS COMPARED TO 24 HOURS, BUT  
THE 00Z NAM APPEARS TO BE A TAD TOO STRONG WITH BOTH OF ITS CLOSED  
LOWS WITH ONE IMPACTING SASKATCHEWAN AND MANITOBA, AND ONE DIGGING  
SOUTH ACROSS BRITISH COLUMBIA. THERE IS NOTABLY BETTER SUPPORT  
FROM THE GEFS MEAN AND ECENS MEAN FOR THE NON-NAM DETERMINISTIC  
SUITE OF GUIDANCE AND PARTICULARLY THE 00Z GFS/ECMWF SOLUTIONS.  
GIVEN THE CONCERNS WITH THE NAM AND UKMET LOCALLY ACROSS THE CONUS  
AND OVER CENTRAL AND SOUTHERN AREAS OF CANADA, A BLEND OF THE GFS  
AND ECMWF WILL BE PREFERRED AT THIS POINT.  
 
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML  
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML  
 
ORRISON  
 

 
 
CLICK HERE TO GO TO PREVIOUS BULLETINS.

The Nexlab HPC Page Main Text Page