809
FXUS10 KWNH 130448
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1248 AM EDT SUN OCT 13 2019
VALID OCT 13/0000 UTC THRU OCT 16/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z INITIAL MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
DEEP PLAINS/UPPER MIDWEST CYCLONE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
THE ANOMALOUSLY DEEP LAYER CYCLONE OVER THE NORTH-CENTRAL U.S.
WILL GRADUALLY WEAKEN AS IT LIFTS NORTHEASTWARD ACROSS ONTARIO,
CANADA OVER THE NEXT COUPLE OF DAYS. THE INITIAL COLD FRONT FROM
THIS LOW HAS REACHED THE EAST COAST BUT IS FORECAST TO STALL
ACROSS THE SOUTHEAST ON SUNDAY AND GOING INTO MONDAY, AND A
SECONDARY COLD FRONT CROSSES THE GREAT LAKES AND OHIO VALLEY
THROUGH SUNDAY NIGHT. THE MODELS REMAIN WELL CLUSTERED WITH THIS
SYSTEM AND THEREFORE A DETERMINISTIC MODEL BLEND IS PREFERRED.
PACIFIC NORTHWEST TO THE NORTHERN PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 00Z GFS/12Z ECMWF
CONFIDENCE: SLIGHTLY ABOVE AVERAGE
THE NEXT FEATURE OF INTEREST TO AFFECT THE WESTERN U.S. WILL BE A
PROGRESSIVE UPPER-LEVEL TROUGH AND ASSOCIATED COLD FRONT THAT
SHOULD REACH THE WEST COAST BY EARLY SUNDAY, AND THEN ADVANCE
INLAND ACROSS THE NORTHERN ROCKIES ON MONDAY. BY MONDAY NIGHT,
THE HEIGHT FALLS START ARRIVING ACROSS THE HIGH PLAINS AND INDUCES
LEE-SIDE CYCLOGENESIS OVER THE CENTRAL PLAINS TO UPPER MIDWEST.
THE GFS AND ECMWF GLOBAL MODELS ARE FAIRLY ALIGNED WITH THEIR
ENSEMBLE MEANS. HOWEVER, THE NAM BECOMES TOO AMPLIFIED OVER THE
NORTHERN PLAINS BY TUESDAY MORNING AND THE CMC IS FARTHER NORTH
WITH THE SURFACE LOW OVER THE NORTHERN GREAT LAKES BY TUESDAY
NIGHT, SO A GFS/ECMWF COMPROMISE IS A GOOD STARTING POINT.
SOUTHWESTERN U.S. TO SOUTHERN PLAINS
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECMWF/EC MEAN/NAM
CONFIDENCE: AVERAGE
TROUGHING MOVING THROUGH THE WESTERN US WILL EVENTUALLY PINCH OFF
A SOUTHERN STREAM SHORTWAVE ACROSS SOUTHERN CALIFORNIA EARLY
MONDAY. IT REMAINS THE CASE THAT THE UKMET AND CMC ARE MORE
AMPLIFIED ALOFT ACROSS THE SOUTHWEST ON MONDAY COMPARED TO THE
OTHER GUIDANCE. BY TUESDAY MORNING, THE GFS AND THE GEFS MEAN ARE
MORE PROGRESSIVE ACROSS THE WESTERN HIGH PLAINS AND THE UKMET/CMC
ARE SLOWER. THE ECMWF IS MORE AMPLIFIED AT 700MB BY TUESDAY
ACROSS THE SAME GENERAL AREA. AT THE SURFACE, THE UKMET IS
DISPLACED TO THE NORTH WITH THE SURFACE LOW OVER THE CENTRAL
PLAINS. TAKING THESE FACTORS INTO ACCOUNT, A BLEND OF THE
ECMWF/EC MEAN/NAM SHOULD SUFFICE FOR NOW.
MODEL TRENDS AT WWW.WPC.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NOAA.GOV/H5PREF/H5PREF.SHTML
HAMRICK
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