515
FXUS10 KWNH 220919
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
419 AM EST FRI NOV 22 2019
VALID NOV 22/0000 UTC THRU NOV 25/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...WEAKENING CLOSED LOW CROSSING THE FOUR CORNERS INTO THE PLAINS
FRIDAY/SATURDAY, PHASING WITH POTENT NORTHERN STREAM SHORTWAVE
ACROSS GREAT LAKES SAT INTO SUN...
...SURFACE LOW MOVING FROM THE LOWER MISSISSIPPI VALLEY INTO THE
CENTRAL APPALACHIANS FRIDAY NIGHT INTO SATURDAY...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
09Z UPDATE: NO SIGNIFICANT CHANGES NOTED WITH THE REST OF THE 00Z
GUIDANCE NOW AVAILABLE. THE GENERAL MODEL BLEND PREFERENCE STILL
APPEARS SUFFICIENT.
---PREVIOUS DISCUSSION---
CLOSED LOW OVER THE SOUTHWEST U.S. AND FOUR CORNERS REGION WILL
CONTINUE TO MAKE PROGRESS EASTWARD OVER THE NEXT COUPLE OF DAYS,
EJECTING OUT INTO THE SOUTHERN/CENTRAL PLAINS FRIDAY NIGHT INTO
SATURDAY. THIS SYSTEM IS THEN FORECAST TO PHASE WITH NORTHERN
STREAM ENERGY OVER THE GREAT LAKES AND LEAD TO A FAIRLY ANOMALOUS
NEGATIVE TILTED TROUGH OVER THE NORTHEAST U.S. BY LATE IN THE
WEEKEND WITH A SURFACE LOW DEEPENING FROM THE TN VALLEY TOWARD THE
MID-ATLANTIC. MODEL AGREEMENT HAS INCREASED SOMEWHAT IN THE LAST
CYCLE OR TWO, ESPECIALLY WITH THE MID/UPPER LEVEL PATTERN WHERE
FOR THE MOST PART, DIFFERENCES ARE MINIMAL. AT THE SURFACE
HOWEVER, THERE REMAINS SOME SPREAD WITH RESPECT TO THE LOW TRACK,
WHERE THE MAJORITY OF THE GEFS MEMBERS ARE SOUTH (SOUTHERN
APPALACHIANS) WHILE THE ECENS MEMBERS ARE TO THE NORTH (OH
VALLEY). AS THE LOW MOVES OFF THE MID-ATLANTIC COAST, THE SPREAD
LESSENS SOME AND THERE IS REASONABLE CONSENSUS. FROM A SENSIBLE
WEATHER PERSPECTIVE, QPF FOOTPRINT IS FAIRLY SIMILAR ACROSS THE
MID-ATLANTIC AND NORTHEAST, WITH DIFFERENCE MAINLY BEING IN
MAGNITUDE. WITH THIS IN MIND, A GENERAL MODEL BLEND WOULD SUFFICE
FOR THIS TIME PERIOD.
...EMBEDDED SHORTWAVES WITHIN STRONG ZONAL NORTHERN PACIFIC JET
INTO THE NORTHWEST...
..ASSOCIATED SURFACE WAVE ACROSS THE NORTHERN TIER BY 00Z MON
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-CMC BLEND
CONFIDENCE: AVERAGE
FAIRLY ACTIVE NORTHERN STREAM ENERGY WILL BRING A PARADE OF
SHORTWAVES ACROSS THE NORTHERN TIER OF THE U.S. DURING THE SHORT
TERM PERIOD WHILE A LARGE CLOSED LOW DRIFTS WELL OFFSHORE THE
SOUTHERN CALIFORNIA COAST. THE LARGE SCALE SYNOPTIC SETUP AND
EVOLUTION IS FAIRLY REPRESENTED BY THE VARIOUS DETERMINISTIC
MODELS THROUGH ABOUT 48 HOURS, BUT THEN THE 12Z CMC SEEMS TO
DIVERGE FROM THE CONSENSUS. IT IS MUCH WEAKER WITH THE ENERGY
COMING INTO THE PAC NW ON SUNDAY AND THEN IS SLOWER WITH THE NEXT
FEATURE COMING IN EARLY NEXT WEEK. SO BOTH ITS TEMPORAL AND
MAGNITUDE DIFFERENCES SUGGEST IT AS AN OUTLIER FROM THIS CYCLE.
OTHERWISE, THE RELATIVELY GOOD CONSENSUS IN MASS FIELDS AND
LIGHTER QPF FAVORS A GENERAL MODEL BLEND (EXCLUDING THE CMC).
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
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