621
FXUS10 KWNH 240653
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
252 AM EDT WED JUN 24 2020
VALID JUN 24/0000 UTC THRU JUN 27/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
CLOSED LOW OVER ONTARIO/QUEBEC
TROUGH CROSSING THE EASTERN U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE UPPER LEVEL LOW IN PLACE OVER THE NORTHERN GREAT LAKES IS
EXPECTED TO LIFT NORTH/NORTHEASTWARD OVER THE NEXT FEW DAYS WHILE
THERE WILL BE SOME SOUTHWARD EXPANSION ON THE LONGWAVE TROUGH OVER
THE EASTERN U.S., WHICH PUSHES A COLD FRONT THROUGH MUCH OF THE
MID-ATLANTIC AND NEW ENGLAND BEFORE WASHING OUT OVER THE
SOUTHEAST. FROM A SYNOPTIC POINT OF VIEW, MASS FIELDS ARE IN GOOD
SHAPE IN THE REGION AND A GENERAL MODEL BLEND IS PREFERRED.
SHORTWAVE CROSSING THE PACIFIC NORTHWEST AND PLAINS
ENERGY DIGGING INTO THE SOUTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z GFS/ECMWF/NAM
CONFIDENCE: AVERAGE
GUIDANCE HAS TRENDED BETTER OVER THE LAST FEW RUNS AND NOW SHOWS
FAIRLY GOOD AGREEMENT IN THE SYNOPTIC PATTERN AS A SHORTWAVE
TROUGH SKIRTS ACROSS THE PACIFIC NORTHWEST INTO THE NORTHERN
ROCKIES. THE UKMET IS A FASTER OUTLIER AND WHILE THE GFS IS ON THE
SLOWER SIDE OF THE GUIDANCE, IT IS CLOSER TO THE OVERALL MEANS AND
ECMWF/NAM. BIGGER DIFFERENCES ARE NOTED ON THE SOUTHERN END, WHERE
SOME OF THE MODELS ADVERTISE SOME ENERGY SEPARATING OUT AND
DIGGING FURTHER SOUTH OVER SOUTHERN CALIFORNIA. THE ECMWF HOLDS
BACK THE ENERGY THE MOST WHILE THE GFS IS A BIT FLATTER/FASTER.
GIVEN THE TWO AREAS OF DIFFERENCES, FROM A MASS FIELD PERSPECTIVE,
A BLEND OF THE GFS/ECMWF/NAM IS PREFERRED.
STRONG SHORTWAVE APPROACHING PACIFIC NORTHWEST THIS WEEKEND
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 00Z ECMWF/GFS
CONFIDENCE: AVERAGE
DURING THE DAY 3 TIME FRAME, A STRONG SHORTWAVE TROUGH FROM THE
GULF OF ALASKA IS FORECAST TO DROP SOUTH ALONG THE B.C. COAST AND
APPROACH THE PACIFIC NORTHWEST BY SATURDAY MORNING. ALL OF THE
DETERMINISTIC GUIDANCE SHOWS THIS FEATURE WITH VARYING DEGREES OF
STRENGTH, THE GFS AND CMC BEING ON THE STRONGER SIDE SHOWING A
CLOSED LOW AT 500 MB WHILE THE NAM AND ECMWF ARE A BIT WEAKER AND
OPEN (ALSO SLOWER). FOR NOW, GIVEN SOME OF THE MODEL SPREAD, A
BLEND OF THE GFS/ECMWF SEEMS SUFFICIENT AT THIS TIME.
LOWER TO MID MS RIVER VALLEY...DEEP SOUTH
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE ECENS/GEFS/CMC/NAM
CONFIDENCE: AVERAGE
07Z UPDATE: THE 00Z UKMET TRENDED BACK TOWARD THE IDEA OF A
WEAKER,SLOWER WAVE COMING OUT OF THE LOWER MS VALLEY AND NOW SHOWS
FAIRLY GOOD AGREEMENT WITH THE OTHER 00Z GUIDANCE.
WEAK FLOW ALOFT WITH PIECES OF SHORTWAVE ENERGY BECOMING REMOVED
FROM THE WESTERLIES WILL DRIFT OVER THE TEXAS GULF COAST AND LOWER
MS VALLEY. THE MODELS ARE STRUGGLING WITH WHAT TO DO WITH THIS
ENERGY AS IT ATTEMPTS TO GET LIFTED BACK NORTHEAST INTO THE LARGER
LONGWAVE TROUGH. THE UKMET IS THE MOST AGGRESSIVE WITH THIS IDEA,
DEVELOPING A STRONGER SHORTWAVE OVER THE SOUTHEAST TOWARD THE NC
COAST BY THE END OF DAY 3. THE OTHER MODELS ALL HAVE SOME FLAVOR
OF HOLDING THE ENERGY BACK, CLOSER TO THE GULF COAST, WHICH IS
GENERALLY FAVORED. THE ECMWF/NAM SHOW THE SLOWEST/WESTERN SOLUTION
WHILE THE GFS TRIES TO LIFT IT NORTHEAST BY DAY 3. GIVEN THE MESSY
MASS FIELDS AND WEAK FLOW GENERALLY, THE SENSIBLE WEATHER IS ALSO
MESSY AND LOW CONFIDENCE. AS SUCH, THE DAY 2 AND PARTICULARLY THE
DAY 3 PREFERENCES FOR A HEAVY WEIGHT OF THE ECENS/GEFS MEANS WITH
SOME INCLUSION OF THE CMC/NAM
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
TAYLOR
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