423
FXUS10 KWNH 030714
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
313 AM EDT WED JUN 3 2020
VALID JUN 3/0000 UTC THRU JUN 6/1200 UTC
...SEE NOUS42 KWNO (ADMSDM) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION INCLUDING FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
UPPER LEVEL LOW SLOWLY LIFTING INTO OKLAHOMA THAT DRIFTS EAST INTO
WEDNESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A BROAD UPPER LOW CURRENTLY CENTERED OVER EASTERN OKLAHOMA WILL
TRACK EASTWARD ACROSS ARKANSAS, AND THEN EVOLVE INTO A BROAD UPPER
LEVEL TROUGH. THE 250-500 MB TROUGH AXIS WILL EXTEND SOUTHWARD
OVER THE NORTHERN GULF OF MEXICO, AND THIS WILL BE IMPORTANT SINCE
UPPER LEVEL FLOW AHEAD OF IT WILL PLAY A ROLE IN THE FUTURE TRACK
OF TROPICAL STORM CRISTOBAL. ALL GLOBAL GUIDANCE ARE IN CLOSE
ENOUGH AGREEMENT ON THE MAIN FEATURES TO MERIT THE USE OF A
MULTI-DETERMINISTIC MODEL BLEND.
CUT-OFF LOW LINGERING SOUTHWEST OF CALIFORNIA THROUGH THURSDAY
BEFORE EJECTING EAST
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: MODERATE-HIGH
A CUT OFF UPPER LOW WILL REMAIN NEARLY ANCHORED IN PLACE THROUGH
THURSDAY WEST OF THE RIDGE AXIS OVER THE SOUTHERN ROCKIES BEFORE
BEGINNING TO EJECT EAST TOWARD SOUTHERN CALIFORNIA BY THURSDAY
NIGHT AND INTO FRIDAY. SIMILAR TO YESTERDAY, THE GFS REMAINS
SLIGHTLY FASTER IN BRINGING THE CLOSED LOW EASTWARD ON FRIDAY
COMPARED TO THE OTHER GUIDANCE, AND THE UKMET AND CMC ARE NOW
SLIGHTLY FASTER THAN THEIR EARLIER RUNS. THE ECMWF AND THE EC
MEAN REMAIN THE SLOWER SOLUTIONS TOWARDS THE END OF THE FORECAST
PERIOD.
ACTIVE FLOW PATTERN ACROSS NORTHERN TIER OF U.S.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND THROUGH THURSDAY, THEN 00Z
ECMWF/UKMET/12Z EC MEAN
CONFIDENCE: MODERATE
THE WESTERLIES ON THE NORTHERN PERIPHERY OF THE CENTRAL U.S. RIDGE
WILL REMAIN ACTIVE WITH TWO WELL-DEFINED SHORTWAVE DISTURBANCES
TRACKING EASTWARD NEAR THE U.S./CANADA BORDER THROUGH THE END OF
THE WEEK. THE FIRST DISTURBANCE IS A SHORTWAVE OVER NORTHERN
MANITOBA WHICH WILL TRACK SOUTH OF THE HUDSON BAY REGION BY
WEDNESDAY AND BE DIRECTED ACROSS NORTHERN MAINE BY A DEEP LOW OVER
LABRADOR, AND RESULT IN A COLD FRONT STALLING OVER THE
EAST-CENTRAL U.S. AND PROVIDE A FOCUS FOR RAINFALL. THE SECOND
SYSTEM, CURRENTLY OVER ALBERTA, WILL TRACK JUST NORTH OF THE
BORDER AND EVOLVE INTO AN UPPER LOW OVER MANITOBA BY WEDNESDAY
NIGHT. THIS WILL SEND A COLD FRONT ACROSS THE NORTHERN GREAT
PLAINS WEDNESDAY NIGHT AND ACROSS THE MIDWEST BY THURSDAY.
DESPITE THE QUASI-ZONAL AND PROGRESSIVE FLOW PATTERN IN PLACE
ACROSS THE REGION, MODELS ARE IN GOOD AGREEMENT THROUGH THURSDAY,
EXCEPT FOR THE 00Z CMC THAT IS WEAKER THAN THE REST OF THE
GUIDANCE WITH EASTWARD PROGRESSION OF THE SECOND WAVE OVER THE
CANADIAN PRAIRIES STARTING LATE WEDNESDAY. THE 00Z GFS BECOMES
SLIGHTLY MORE AMPLIFIED WITH THE SECOND WAVE BY THURSDAY EVENING
ACROSS THE NORTHERN PLAINS, AND THE NAM IS SLOWER WITH IT BY
FRIDAY AS IT CROSSES THE NORTHERN GREAT LAKES REGION.
CLOSED LOW DRIFTING SOUTH FROM GULF OF ALASKA BY FRIDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND THROUGH 12Z FRIDAY, THEN NON-CMC
BLEND
CONFIDENCE: MODERATE-HIGH
AN UPPER LEVEL LOW ORIGINATING OVER THE GULF OF ALASKA IS EXPECTED
TO DROP SOUTHEASTWARD, WEST OF THE BRITISH COLUMBIA COAST, AND BE
SITUATED SEVERAL HUNDRED MILES WEST OF THE WASHINGTON COAST BY
SATURDAY MORNING. EXCEPT FOR A SLIGHTLY SLOWER CMC BEYOND FRIDAY
MORNING, THERE IS ENOUGH DETERMINISTIC MODEL AGREEMENT TO MERIT
THE USE OF A GENERAL MODEL BLEND FOR THIS REGION.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.SHTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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