637
FXUS10 KWNH 270714
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
214 AM EST MON JAN 27 2020
VALID JAN 27/0000 UTC THRU JAN 30/1200 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
00Z MODEL EVALUATION WITH FINAL PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
...SHORTWAVE DIVING ACROSS THE PLAINS TO OFF THE NORTH CAROLINA
COAST TONIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM 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.
THE NAM IS A BIT STRONG BUT ALSO A BIT FAST WITH THIS ENERGY WHEN
COMPARED TO THE OTHER GUIDANCE AND THE CONSENSUS. ALTHOUGH THE
DIFFERENCES ARE MINIMAL, SINCE THE REMAINING SUITE IS IN LOCK
STEP, CHOSE TO REMOVE THE NAM FROM THE PREFERRED BLEND.
...SPLIT FLOW TROUGH CROSSING THE MOUNTAIN WEST TODAY AND REACHING
THE SOUTHEAST WEDNESDAY NIGHT...
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GEFS/GFS/ECMWF/ECENS
CONFIDENCE: BELOW AVERAGE
07Z UPDATE: TREND IN THE GUIDANCE HAS BEEN FOR A DEEPER 500/700MB
TROUGH DIGGING INTO THE SOUTHERN PLAINS EARLY D2, BUT STILL
CONSIDERABLE SPREAD EXISTS BY D3 AS THE TWO MID-LEVEL IMPULSES TRY
TO INTERACT ACROSS THE SOUTHEAST. WHILE THE D2 PERIOD IS BEGINNING
TO FAVOR A DEEPER SOLUTION, WHICH BRINGS THE 00Z GFS BACK INTO THE
BLEND, THE LONGITUDINAL SEPARATION OF THE NORTHERN AND SOUTHERN
STREAM ON D3 IS INCREASING, SUGGESTING LESS INTERACTION ACROSS
THAT REGION.
PROGRESSIVE SPLIT FLOW TROUGH MOVING ACROSS THE MOUNTAIN WEST THIS
MORNING WILL MOVE ACROSS THE CONUS AS THE SOUTHERN STREAM BECOMES
DOMINANT, WITH A CLOSED LOW LIKELY DEVELOPING ACROSS THE SOUTHERN
PLAINS AND INTO THE SOUTHEAST BY THE MIDDLE OF THE WEEK. THE
NORTHERN STREAM PORTION WILL NOT DISSIPATE, HOWEVER, AND THE
GUIDANCE DIVERGES BY D3 INTO HOW MUCH INTERACTION WILL OCCUR WITH
THE TWO IMPULSES.
THE UKMET CONTINUES TO BE A SHALLOW AND FAST OUTLIER, BUT IS
SHOWING SOME SIGNS OF DEEPENING TOWARDS THE GLOBAL CONSENSUS IN
ITS LAST FEW RUNS. STILL, IT IS OUTSIDE THE ENSEMBLE ENVELOPE WITH
ITS POSITION AND INTENSITY. THE NAM REMAINS SLOW OVERALL AS THE
FEATURE DEEPENS, WHICH MAKES SIGNIFICANT QPF DIFFERENCES (HEAVIER
FURTHER NORTH AND WEST) INTO THE SOUTHERN PLAINS D2. THE GFS IS A
BIT STRONGER THAN THE MEAN WITH THE SOUTHERN ENERGY, AND KEEPS THE
AMOUNT OF INTERACTION, ESPECIALLY BY D3, OF THE TWO FEATURES TO A
MINIMUM. THIS AGREES WITH THE CMC, ALTHOUGH THE CMC APPEARS TO BE
TOO FAST WITH THE SOUTHERN STREAM IMPULSE WHICH IS WHY THE LEVEL
OF INTERACTION IS SO WEAK. THIS LEAVES THE ECMWF/ECENS/GEFS WHICH
ARE IN GOOD AGREEMENT WITH THE TIMING AND DEPTH OF THE SOUTHERN
STREAM ENERGY, AND PROVIDE A LITTLE MORE IMPETUS FOR INTERACTION
BY D3 ACROSS THE SOUTHEAST.
...PROGRESSIVE UPPER TROUGH OVER THE PACIFIC NORTHWEST AND
AMPLIFYING INTO THE SOUTHERN PLAINS WEDNESDAY.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: ECENS/GEFS MEANS WITH SOME WEIGHT OF THE 00Z/27 NAM
CONFIDENCE: SLIGHTLY BELOW AVERAGE
YET ANOTHER IN A SERIES OF PACIFIC SHORTWAVE TROUGHS WILL ARRIVE
ON TUESDAY ACROSS THE PACIFIC NORTHWEST, AND THEN DIG INTO THE
WEST ON WEDNESDAY, WITH THE GRADUAL DEVELOPMENT OF A CLOSED LOW
OVER THE SOUTHWEST LATE WEDNESDAY. THERE IS GOOD AGREEMENT IN THE
BROAD SCALE, BUT FINER RESOLUTION DIFFERENCES IN THE TIMING OF THE
LOW CLOSING OFF, AS WELL AS TO WHAT LATITUDE THIS WILL OCCUR ARE
CONSIDERABLE. THE ECMWF IS FAST TO CLOSE OFF THE UPPER LOW OVER
MEXICO, AND IS ALSO THE FURTHEST SOUTH OF THE GLOBAL MODELS. IT IS
WELL SOUTH OF ITS MEAN AS WELL, WHICH IS WELL COLLOCATED WITH THE
NAM AND GEFS MEAN. THE CMC AND UKMET ARE MUCH FURTHER EAST WITH
THE TROUGH AXIS BY D3, LIKELY TOO PROGRESSIVE DUE TO BEING WEAKER.
A BLEND OF THE ECENS/GEFS MEAN SEEMS MOST APPROPRIATE, BUT SOME
NAM WOULD HELP WITH THE FINER DETAILS OF QPF IN THE TERRAIN AS ITS
MASS FIELDS ARE REASONABLE.
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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