432
FXUS10 KWNH 261819
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
216 PM EDT SUN JUL 26 2020
VALID JUL 26/1200 UTC THRU JUL 30/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION INCLUDING PREFERENCES AND FORECAST CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..MID-UPPER LEVEL TROUGHING OVER THE NORTHERN CONUS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
NO CHANGES TO THE PREVIOUS THINKING. MID TO UPPER-LEVEL ENERGY
OVER SOUTHERN CANADA IS EXPECTED TO CLOSE OFF BEFORE SETTLING OVER
ONTARIO LATER IN THE PERIOD, WHILE THE LARGER SCALE TROUGH DEEPENS
OVER THE GREAT LAKES REGION. AT THE SURFACE, A PRONOUNCED COLD
FRONT IS FORECAST TO MARCH ACROSS THE NORTHERN TIER INTO THE GREAT
LAKES WHILE UPSTREAM RIDGING BUILDS OVER THE CANADIAN ROCKIES. IN
THE INCREASINGLY AMPLIFIED PATTERN, THE MODELS HAVE CONVERGED ON A
SIMILAR IDEA AND SHOW VERY GOOD AGREEMENT THROUGH 84 HOURS WITH
THE SYNOPTIC PATTERN.
..MID-LEVEL ENERGY OVER CALIFORNIA/GREAT BASIN
..ENERGY ADVANCING SOUTHEAST ACROSS THE PLAINS BY WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND...THROUGH 72 HOURS
NON-NAM BLEND...AFTER 72 HOURS
CONFIDENCE: ABOVE AVERAGE
A BROAD UPPER TROUGH AND EMBEDDED CLOSED LOW OVER CA WILL DRIFT
EAST-NORTHEAST OVER THE NEXT COUPLE OF DAYS AND CROSS INTO THE
GREAT BASIN AROUND THE NORTH SIDE OF THE SUBTROPICAL RIDGE OVER
THE SOUTHWEST AND THE SOUTHERN PLAINS. THIS ENERGY THEN IS
EXPECTED TO ACTUALLY AMPLIFY A BIT OVER PORTIONS OF THE NORTHERN
ROCKIES BY WEDNESDAY AND THEN DIG SOUTHEAST OUT ACROSS THE PLAINS.
THE MODELS OVERALL SHOW GOOD SYNOPTIC SCALE AGREEMENT THROUGH MOST
OF THE PERIOD. HOWEVER, THE 12Z NAM DOES GENERALLY APPEAR TO BE A
TAD TOO SLOW AND TOO FAR NORTH WITH ITS ENERGY OVER THE PLAINS ON
WEDNESDAY. THE 12Z NAM AND 12Z GFS BOTH MAY ALSO BE A TAD TOO
STRONG, BUT THERE IS ROOM FOR A SOMEWHAT STRONGER CLOSED MID-LEVEL
LOW TO EVOLVE OVER THE CENTRAL PLAINS BY THE END OF THE PERIOD
CONSIDERING THE NOTABLE STRENGTHENING OF THE SUBTROPICAL RIDGE
OVER THE DESERT SOUTHWEST. A GENERAL MODEL BLEND WILL BE PREFERRED
THROUGH 72 HOURS, WITH A NON-NAM BLEND THEREAFTER GIVEN SOME OF
ITS ENERGY PLACEMENT CONCERNS.
..SHORTWAVE TROUGHS APPROACHING CA/PACIFIC NORTHWEST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-UKMET BLEND
CONFIDENCE: ABOVE AVERAGE
A PAIR OF NEW SHORTWAVES TROUGH WILL BE APPROACHING THE WEST COAST
OVER THE NEXT FEW DAYS, WITH ONE ARRIVING OVER THE PACIFIC
NORTHWEST ON TUESDAY, AND ONE ARRIVING ACROSS CA ON WEDNESDAY.
GENERALLY THE MODELS ARE IN GOOD AGREEMENT, WITH STRONG EXCEPTION
TO THE 12Z UKMET WHICH IS MUCH TOO SLOW WITH THE ENERGY
APPROACHING CA ON WEDNESDAY. THE UKMET OVERALL ENDS UP MORE OUT OF
PHASE RELATIVE TO THE OTHER MODELS WITH THE ENERGY OVER THE
PACIFIC NORTHWEST AND EVEN A RATHER STRONG CLOSED LOW THAT IS
SITUATED SOUTH OF THE GULF OF AK AT THE END OF THE PERIOD. A
NON-UKMET BLEND WILL AGAIN BE PREFERRED FOR THE TIME BEING.
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.
ORRISON
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