881
FXUS10 KWNH 011702
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
101 PM EDT MON JUN 01 2020
VALID JUN 01/1200 UTC THRU JUN 05/0000 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z INITIAL MODEL EVALUATION INCLUDING FINAL PREFERENCES AND
CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
UPPER LEVEL LOW SLOWLY LIFTING ACROSS WEST TEXAS AND INTO OKLAHOMA
THROUGH TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A BROAD UPPER LOW CURRENTLY CENTERED OVER WEST TEXAS WILL CONTINUE
TO SLOWLY LIFT NORTHWARD INTO OKLAHOMA THROUGH TUESDAY EVENING
BEFORE WEAKENING AS IT ENTERS THE BROAD UPPER RIDGE AXIS ACROSS
THE MID-SOUTH BY WEDNESDAY. ALL GLOBAL GUIDANCE ARE IN CLOSE
ENOUGH AGREEMENT ON THE MAIN FEATURES TO MERIT THE USE OF A
MULTI-DETERMINISTIC MODEL BLEND.
DEVELOPING LOW BECOMING CUT-OFF AND LINGERING WEST OF BAJA
CALIFORNIA THROUGH MIDWEEK
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A DEVELOPING UPPER LEVEL LOW WILL BECOME PINCHED OFF FROM THE
WESTERLIES FARTHER NORTH, AND BECAUSE OF THE RIDGE AXIS OVER THE
SOUTHERN ROCKIES, IT WILL WOBBLE IN PLACE INTO THURSDAY BEFORE
BEGINNING TO EJECT EAST TOWARD THE CA/MEXICO BORDER LATER
THURSDAY. PLACEMENT AND DEPTH ARE IN EXCELLENT AGREEMENT THROUGH
THURSDAY AMONG GLOBAL DETERMINISTIC GUIDANCE AND A GENERAL MODEL
BLEND IS RECOMMENDED.
ACTIVE FLOW PATTERN ACROSS NORTHERN TIER OF U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
THE WESTERLIES ON THE NORTHERN PERIPHERY OF THE CENTRAL U.S. RIDGE
ARE EXPECTED TO BE RATHER ACTIVE WITH FOUR WELL DEFINED SHORTWAVE
DISTURBANCES TRACKING EASTWARD NEAR THE U.S./CANADA BORDER THROUGH
THURSDAY. THE FIRST SHORTWAVE, CURRENTLY WEST OF LAKE SUPERIOR
WILL TRACK EAST-SOUTHEAST ACROSS PA LATE TONIGHT INTO TUESDAY AND
PRODUCE A STREAK OF PRECIP FROM MI INTO PA TONIGHT. THE SECOND
WAVE IS AN OCCLUDED LOW MOVING INTO NORTHERN MANITOBA WHICH WILL
WEAKEN, BUT SHIFT SOUTHEAST WITH SURFACE LOW PRESSURE ACROSS
NORTHERN NY STATE AND SOUTHERN NEW ENGLAND TUESDAY NIGHT. THIS
WILL LEAVE A COLD FRONT OVER THE NORTHEASTERN TO NORTH CENTRAL
CONUS WHICH WILL BE A FOCUS FOR CONVECTIVE WEATHER THROUGH
THURSDAY. THE THIRD DISTURBANCE IS A WAVE OVER BC WHICH WILL TRACK
ACROSS THE UPPER CANADIAN PRAIRIES TO HUDSON BAY THROUGH TUESDAY
NIGHT WHICH WILL LEAVE A FRONT NEAR THE CANADIAN BORDER WHICH WILL
DIRECT THE NEXT AND FOURTH SYSTEM WHICH WILL REACH THE BC COAST
LATE TUESDAY WHICH WILL TRACK JUST NORTH OF THE BORDER WEDNESDAY
AND DRAG A COLD FRONT ACROSS THE NORTHERN GREAT PLAINS WEDNESDAY
NIGHT. WEAKER IMPULSES FROM THE NORTH PACIFIC FOLLOW THIS FOURTH
WELL-DEFINED WAVE.
MODELS ARE ALL IN EXCELLENT AGREEMENT WITH THE FIRST THREE WAVES
WHICH MAINLY AFFECT THE DAY 1 AND 1.5 (THROUGH TUESDAY NIGHT)
FORECAST. THE 00Z CMC IS TOO FAST AND WEAK WITH THE LAST WAVE ONCE
IT PUSHES ONTO THE SOUTHERN CANADIAN PRAIRIES ON WEDNESDAY. THE
00Z ECMWF/UKMET AND 12Z GFS/NAM ARE ALL IN GOOD ENOUGH STRENGTH
AND POSITION WITH THIS LOW THAT THEY CAN BE USED AS GOOD
REFERENCES FOR THIS SYSTEM WHICH IS THE DOMINANT DAY 2/3 SYSTEM.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
JACKSON
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