882
FXUS10 KWNH 271831
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
130 PM EST MON JAN 27 2020
VALID JAN 27/1200 UTC THRU JAN 31/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...SHORTWAVE DIVING ACROSS THE PLAINS TO OFF THE NORTH CAROLINA
COAST TONIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
GUIDANCE IS IN GOOD AGREEMENT IN SPATIAL AND INTENSITY EVOLUTION
OF THIS FEATURE AS IT SHEARS OFF TO THE EAST TODAY AND TONIGHT.
...SPLIT FLOW TROUGH CROSSING THE MOUNTAIN WEST TODAY AND REACHING
THE SOUTHEAST WEDNESDAY NIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: 12Z GFS/ECMWF/UKMET
CONFIDENCE: AVERAGE
19Z UPDATE: THE 12Z CMC HAS COME INTO A BIT BETTER AGREEMENT WITH
THE BETTER MODEL CLUSTERING INITIALLY, BUT IT STILL BECOMES A
PRETTY CLEAR OUTLIER BY 00Z THURSDAY WITH A STRONGER/SLOWER WAVE
ENTERING THE OHIO VALLEY. THUS WOULD STILL PREFER TO LEAVE OFF THE
CMC FROM OUR PREFERENCES. THE 12Z UKMET DID TREND CLOSER TO THE
GFS/ECMWF CLUSTER, ALTHOUGH IS A TOUCH SLOWER WITH THE TROUGH
MOVEMENT. ALL IN ALL THINK A COMBINATION OF THE 12Z
ECMWF/GFS/UKMET RESULTS IN A PRETTY GOOD STARTING POINT FOR THIS
SYSTEM...WITH THE NAM AND CMC STILL NOT PREFERRED.
THE NEW 12Z GFS HAS COME INTO PRETTY GOOD AGREEMENT SYNOPTICALLY
WITH THE 00Z ECMWF WITH REGARDS TO HOW THE SHORTWAVE ENERGY WITHIN
THE CENTRAL U.S. TROUGH EVOLVES AS IT MOVES INTO THE SOUTHEASTERN
PORTION OF THE COUNTRY WEDNESDAY NIGHT INTO THURSDAY. THE 12Z NAM
HAS THE SAME IDEA INITIALLY, BUT IS OVERALL SLOWER THAN THE BETTER
CONSENSUS, WHICH EVENTUALLY RESULTS IN A FLATTER, YET MORE
ENERGETIC WAVE OVER THE SOUTHERN MID ATLANTIC ON THURSDAY. WILL
LEAN AGAINST THIS SOLUTION AT THIS TIME SINCE THE NAM PRETTY
QUICKLY BECOMES A SLOW OUTLIER WITH THIS TROUGH EVOLUTION. THE 00Z
CMC QUICKLY BECOMES AN OUTLIER WITH ITS HANDLING OF THE SHORTWAVE
ENERGY OVER THE PLAINS BY TUESDAY AFTERNOON. GIVEN HOW QUICK THE
CMC DEVIATES FROM THE BETTER MODEL CLUSTERING, WOULD NOT RECOMMEND
USING IT WITH THIS SYSTEM...AND WOULD EXPECT WE WILL SEE THE 12Z
RUN AT LEAST COME A BIT MORE IN LINE WITH THE GFS/ECMWF IDEA. THE
00Z UKMET INITIALLY LOOKS SIMILAR TO THE GFS/ECMWF CLUSTER, BUT
ENDS UP BECOMING FLATTER BY LATER WEDNESDAY INTO THURSDAY OVER THE
EAST. THERE MAY BE SOME ROOM FOR THE GFS/ECMWF TO BECOME A BIT
FLATTER, BUT THINK THE UKMET IS LIKELY TOO MUCH SO. THUS AT THIS
POINT A GFS/ECMWF BLEND SEEMS TO OFFER THE BEST SOLUTION FOR THIS
SYSTEM.
...PROGRESSIVE UPPER TROUGH OVER THE PACIFIC NORTHWEST AND
AMPLIFYING INTO THE SOUTHERN PLAINS WEDNESDAY.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
19Z UPDATE: THE SPREAD IN THE 12Z SUITE OF GUIDANCE HAS CONTINUED
TO TIGHTEN A BIT OVER THE SOUTHWEST BY DAYS 2/3. THUS A GENERAL
MODEL BLEND STILL LOOKS IN GOOD SHAPE. THE GFS/UKMET ARE A BIT
MORE PROGRESSIVE, WITH THE NAM/CMC/ECMWF CLUSTERED WELL A BIT
SLOWER/SOUTH WITH THE DEVELOPING CLOSED LOW. TRENDS SUGGEST
SOMEWHERE IN THE MIDDLE IS THE MOST PROBABLE OUTCOME AT THIS TIME.
YET ANOTHER IN A SERIES OF PACIFIC SHORTWAVE TROUGHS WILL ARRIVE
ON TUESDAY ACROSS THE PACIFIC NORTHWEST, AND THEN DIG INTO THE
SOUTHWEST LATER WEDNESDAY INTO THURSDAY. AGREEMENT REMAINS PRETTY
GOOD ON THE BROAD SCALE. COMPARING THE FULL SUITE OF ENSEMBLES,
THE 00Z ECWMF REMAINS A BIT FURTHER SOUTH WITH THE ENERGY BY 12Z
THURSDAY, WITH THE 00Z UKMET ON THE NORTHERN EDGE OF THE FULL
ENSEMBLE ENVELOPE. HOWEVER NEITHER OF THESE SOLUTIONS ARE
DIFFERENT ENOUGH TO BE RULED OUT AT THIS POINT. THUS IN GENERAL
THINK A GENERAL BLEND/CONSENSUS SHOULD WORK OKAY WITH THIS SYSTEM
FOR THE TIME BEING THROUGH 00Z FRIDAY.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
CHENARD
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