632
FXUS10 KWNH 300637
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
237 AM EDT THU JUL 30 2020
VALID JUL 30/0000 UTC THRU AUG 02/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...MID-UPPER LEVEL TROUGHING OVER THE NORTHEAST TO THE OHIO VALLEY
AND MID ATLANTIC...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF UKMET/NAM/ECMWF
CONFIDENCE: AVERAGE
THE MODELS INDICATE A DEEP LAYER TROUGH DRIFTS EAST ACROSS NEW
ENGLAND, WITH FAIRLY GOOD CLUSTERING OF SOLUTIONS, ALLOWING A
CONSENSUS BASED APPROACH TO BE USED.
DIFFERENCES EXIST AS THE WAVY FRONT IN THE OHIO VALLEY MOVES EAST
ACROSS THE APPALACHIANS ACROSS THE MID ATLANTIC STATES.
THE GFS LACKS WAVES ON THE FRONT NOTED IN THE
NAM/UKMET/CANADIAN/ECMWF, SO THE GFS IS LEAST PREFERRED. THE
NAM/ECMWF/UKMET/CANADIAN HAVE TIMING/PHASING DIFFERENCES. A BLEND
OF THESE SOLUTIONS IS PREFERRED TO UTILIZE INTERMEDIATE TIMING
UNTIL BETTER AGREEMENT DEVELOPS.
...ENERGY ADVANCING SOUTH FROM THE PLAINS THURSDAY TO THE LOWER MS
VALLEY FRI AND OHIO VALLEY SAT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF 00Z NAM/12Z UKMET/00Z ECMWF
CONFIDENCE: AVERAGE
MID-LEVEL ENERGY COMING OUT OF THE CENTRAL PLAINS SLOWLY SAGS
SOUTHEASTWARD TOWARD THE OZARKS ON FRIDAY AND AMPLIFIES IN THE
LARGER SCALE TROUGHING ALONG THE MS RIVER VALLEY THROUGH THE GREAT
LAKES REGION BY SATURDAY MORNING. THE MODELS DEVELOP LOW PRESSURE
IN THE LOWER MS RIVER VALLEY FRI NIGHT TO EARLY SAT. THE 00Z
GFS/12Z CANADIAN WERE FASTER IN THE LOW PRESSURE PROGRESSION,
WHICH ARE LEAST FAVORED AS USUALLY AMPLIFYING TROUGHS FAVOR SLOWER
MOVING, MORE AMPLIFIED SYSTEMS.
SO THE PREFERENCE HERE IS THE CLUSTER OF THE 00Z ECMWF/12Z UKMET
AND 00Z NAM. THE 00Z UKMET BECAME A DEEP, SLOW OUTLIER SO THERE
IS MORE CONFIDENCE IN THE 12Z UKMET THAN 00Z RUN.
...TROPICAL STORM ISAIAS PROXIMITY TO FL/ THE SOUTHEAST COAST THIS
WEEKEND...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NHC ADVISORY
CONFIDENCE: REFER TO NHC PRODUCTS
THE MODELS HAVE SIGNIFICANT DIFFERENCES ON THE TRACK OF TROPICAL
STORM ISAIAS, WITH THE 12Z-00Z ECMWF/00Z NAM OVERALL A BIT CLOSER
TO THE NHC TRACK, WITH THE 00Z GFS/12Z CANADIAN GLOBAL WELL
REMOVED FROM THE OFFICIAL TRACK. THE 00Z UKMET HAS A SIMILAR
TRACK, BUT SLOWER TIMING. FOR THE LATEST INFORMATION ON TROPICAL
STORM ISAIAS, PLEASE SEE THE LATEST NHC ADVISORY.
...COLD FRONT MOVING THROUGH THE NORTH-CENTRAL U.S. FRIDAY AND
SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF ECMWF/GFS/NAM
CONFIDENCE: AVERAGE
THERE IS RELATIVELY GOOD AGREEMENT FOR THE TROUGH AXIS AND RELATED
COLD FRONT IMPACTING THE NORTH-CENTRAL U.S. THROUGH SATURDAY.
WHILE MINOR TIMING DIFFERENCES ARE EVIDENT, SUCH AS THE LOW
PRESSURE ALONG THE FRONT 00Z SAT IN DIFFERENT LOCATIONS AMONG THE
GFS/CMC/UKMET, THE DIFFERENCES ARE SMALL ENOUGH TO ALLOW FOR A
GENERAL MODEL BLEND AT THIS TIME.
..UPPER LOW/TROUGH APPROACHING THE PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF ECMWF/GFS/NAM
CONFIDENCE: AVERAGE
DUE TO THE HIGH AMPLITUDE DOWNSTREAM RIDGE OVER THE INTERIOR WEST,
THE MID-UPPER TROUGH OVER THE EASTERN PACIFIC WILL BE SLOW TO MOVE
EAST. THERE ARE NO SIGNIFICANT DIFFERENCES NOTED WITH THIS SYSTEM,
WITH A LEAD SHORT AMPLITUDE PROGRESSIVE 700 MB WAVE MOVING NORTH
ACROSS WA INCLUDED ON DAY 2.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
THIS PRODUCT WILL TERMINATE AUGUST 15, 2020:
WWW.WEATHER.GOV/MEDIA/NOTIFICATION/PDF2/SCN20-58PMDHMD_TERMINATION.
PETERSEN
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