005
FXUS10 KWNH 311847
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
247 PM EDT SUN MAY 31 2020
VALID MAY 31/1200 UTC THRU JUN 04/0000 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.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 12Z TUESDAY
CONFIDENCE: AVERAGE
WHILE DIFFERENCE CONTINUE TO DEVELOP DOWNSTREAM ACROSS ATLANTIC
CANADA, MODELS REMAIN IN GOOD AGREEMENT WITH THE EVOLUTION OF THE
UPPER TROUGH AS IT CONTINUES TO SWING ACROSS THE NORTHEAST U.S.
THROUGH EARLY TUESDAY. EAST OF THE U.S. THERE CONTINUES TO BE
MORE NON-NCEP MODEL SUPPORT FOR A CLOSED LOW DEVELOPING OVER NOVA
SCOTIA BY LATE TUESDAY.
UPPER LEVEL LOW SLOWLY LIFTING FROM NORTHERN MEXICO INTO THE
SOUTHERN PLAINS SUNDAY-TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
OVERALL, MODELS ARE IN GENERALLY GOOD AGREEMENT - SHOWING A BROAD
UPPER LOW DRIFTING NORTH ACROSS THE SOUTHERN PLAINS THROUGH EARLY
TUESDAY BEFORE WEAKENING AS REMNANT ENERGY SPREADS EAST INTO THE
LOWER MISSISSIPPI VALLEY ON WEDNESDAY.
SHORTWAVE LIFTING ACROSS THE PACIFIC NORTHWEST INTO CENTRAL CANADA
LATE SUNDAY INTO EARLY MONDAY,
THEN DROPPING SOUTHEAST INTO THE NORTHEAST U.S. LATE TUESDAY INTO
EARLY WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND, BUT WITH LESS WEIGHT GIVEN TO THE
12Z GFS/GEFS MEAN LATE TUESDAY AND WEDNESDAY
CONFIDENCE: AVERAGE
MODELS ARE IN GOOD AGREEMENT THROUGH EARLY MONDAY, SHOWING THE
SHORTWAVE TROUGH CURRENTLY OVER THE PACIFIC NORTHWEST LIFTING
NORTHEAST ACROSS THE CANADIAN ROCKIES AND INTO CENTRAL CANADA BY
EARLY MONDAY. TIMING AND AMPLITUDE DIFFERENCES BEGIN TO DEVELOP
AS THE SYSTEM BEGINS TO WEAKEN AND MOVE EAST ACROSS THE TOP OF AN
UPPER RIDGE, BEFORE SPILLING SOUTHEAST ACROSS NORTHERN ONTARIO AND
WESTERN QUEBEC INTO THE NORTHEAST U.S. TUESDAY NIGHT INTO
WEDNESDAY. DIFFICULT TO COMPLETELY RULE OUT ANY SOLUTION;
HOWEVER, SUSPECT 12Z GFS AND GEFS MEAN MAY BE A LITTLE SLOW, BOTH
WITH THE WEAK WAVE DROPPING SOUTHEAST INTO NORTHEAST U.S.
WEDNESDAY MORNING AND WITH THE TRAILING FRONT EXTENDING BACK
ACROSS THE GREAT LAKES. THE PROGRESSIVE NATURE OF THE FLOW, ALONG
WITH THE MODEL CONSENSUS WOULD TEND TO SUPPORT SOMETHING FASTER.
THE 00Z ECMWF, WHICH LOOKED TO BE A LITTLE TOO AMPLIFIED GIVEN THE
CONFLUENT FLOW ALOFT, HAS BACKED AWAY FROM THAT SOLUTION WITH ITS
12Z RUN.
UPPER LEVEL TROUGH MOVING FROM THE PACIFIC NORTHWEST MONDAY TO THE
NORTHERN PLAINS AND UPPER MIDWEST TUESDAY-WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: LEAN TOWARD THE UKMET/ECMWF/00Z EC ENSEMBLE MEAN
CONFIDENCE: BELOW AVERAGE
MODELS CONTINUE TO SHOW TIMING AND AMPLITUDE DIFFERENCES WITH THIS
FEATURE, ESPECIALLY AS IT MOVES EAST OF THE CASCADES MONDAY NIGHT.
BY LATE MONDAY AS THE SYSTEM MOVES ACROSS THE PACIFIC NORTHWEST,
THE NCEP GUIDANCE IS GENERALLY DEEPER THAN THE UKMET, ECMWF AND
00Z EC ENSMEAN. THIS CONTINUES DOWNSTREAM ACROSS THE NORTHERN
ROCKIES AND THROUGH THE NORTHERN PLAINS AND UPPER MIDWEST, WITH
THE NCEP GUIDANCE BECOMING SLOWER AS WELL THAN THE FLATTER UKMET,
ECMWF AND EC ENSMEAN. GIVEN THE PROGRESSIVE NATURE OF THE FLOW,
RECOMMEND LEANING TOWARD THE FASTER/FLATTER SOLUTIONS.
CUT-OFF LOW DEVELOPING WEST OF SOUTHERN CALIFORNIA EARLY IN THE
WEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: LEAN TOWARD THE ECMWF/00Z EC ENSEMBLE MEAN
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
MODELS ARE IN GOOD AGREEMENT INDICATING A CLOSED, CUT-OFF LOW
DEVELOPING OFF OF THE SOUTHERN CALIFORNIA AND NORTHERN BAJA
CALIFORNIA COASTS LATE MONDAY INTO EARLY TUESDAY. THERE ARE STILL
SOME MODEL DIFFERENCES WITH RESPECT TO POSITION LATER IN THE
PERIOD, WITH MOST OF THE GUIDANCE INDICATING A CENTER SOUTHWEST OF
THE GFS AND GEFS MEAN. COMPARED WITH ITS 00Z RUN, THE 12Z GFS IS
SHOWING SOME SHIFT IN THAT DIRECTION AS WELL - LENDING SUPPORT FOR
A MORE SOUTHWESTERLY SOLUTION, SUCH AS THE ECMWF AND EC ENSEMBLE
MEAN.
SHORTWAVE MOVING ACROSS WESTERN CANADA AND THE NORTHWESTERN U.S.
LATE TUESDAY-EARLY WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: LEAN TOWARD THE ECMWF/00Z EC ENSEMBLE MEAN
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE NCEP GUIDANCE, ESPECIALLY THE GFS, IS MORE AMPLIFIED THAN THE
GENERAL DETERMINISTIC AND ENSEMBLE CONSENSUS AS THE SYSTEM MOVES
EAST OF THE ROCKIES INTO THE CANADIAN PRAIRIE AND U.S. HIGH PLAINS
WEDNESDAY MORNING.
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.
Main Text Page