537
FXUS10 KWNH 011922
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
318 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 FINAL MODEL EVALUATION INCLUDING 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 NORTHWEST TEXAS WILL
CONTINUE TO SLOWLY LIFT NORTHWARD INTO OKLAHOMA TONIGHT BEFORE
WEAKENING THROUGH TUESDAY NIGHT EAST OF BROAD UPPER RIDGE AXIS
OVER THE SOUTHERN ROCKIES. 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 GOOD ENOUGH AGREEMENT THROUGH
THURSDAY AMONG GLOBAL DETERMINISTIC GUIDANCE AND A GENERAL MODEL
BLEND IS RECOMMENDED. ONE NOTE IS THE 12Z UKMET AND ECMWF ARE A
BIT DEEPER WITH THE LOW CENTER BY LATE THURSDAY WHICH MAY SLOW THE
EASTERN EJECTION OF THE LOW WHICH IS NOTED BEYOND THE DAY 3
TIMEFRAME WITH THE GFS BEING MORE PROGRESSIVE.
ACTIVE FLOW PATTERN ACROSS NORTHERN TIER OF U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE
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.
THERE ARE ESSENTIALLY TWO CAMPS WITH THE POSITION OF THE COLD
FRONT OVER THE MIDWEST WEDNESDAY NIGHT/THURSDAY WHICH IS
ASSOCIATED WITH THE OCCLUDED LOW REMNANTS THAT SHIFT OFF THE
SOUTHERN NEW ENGLAND COAST TUESDAY NIGHT. THE 12Z ECMWF/CMC AGREE
ON A FARTHER NORTH SOLUTION WHILE THE 12Z UKMET/GFS ARE SLIGHTLY
FARTHER SOUTH WITH THE 12Z NAM SOMEWHAT IN BETWEEN. GIVEN THE
POSITION OF THE FRONT ON DAY 3 HAS AN UNDERSTANDABLE DIFFERENCE, A
GENERAL MODEL BLEND IS RECOMMENDED.
THE 12Z CMC HAS COME IN BETTER AGREEMENT WITH CONSENSUS WITH THE
PROGRESSION OF THE LAST LOW TRACKING OVER THE SOUTHERN CANADIAN
PRAIRIES WEDNESDAY/WEDNESDAY NIGHT.
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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