929
FXUS10 KWNH 251852
PMDHMD
MODEL DIAGNOSTIC DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
151 PM EST SAT JAN 25 2020
VALID JAN 25/1200 UTC THRU JAN 29/0000 UTC
...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR
INGEST...
12Z MODEL EVALUATION WITH LATEST PREFERENCES AND CONFIDENCE
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
..DEEP CLOSED LOW MOVING ACROSS THE NORTHEAST THROUGH SUNDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: ABOVE AVERAGE
VERY GOOD AGREEMENT PERSISTS IN THE EVOLUTION OF A STRONG CLOSED
LOW CURRENTLY ACROSS THE OHIO VALLEY LIFTING NORTHEAST SLOWLY
THROUGH THE WEEKEND. THE MAIN CORE OF THIS FEATURE HAS GOOD MODEL
CONSENSUS THAT IT WILL DRIFT THROUGH NEW ENGLAND BY SUNDAY AND
THEN OVER ATLANTIC CANADA ON MONDAY. THE GUIDANCE AT LEAST THROUGH
MONDAY IS AGREEABLE SUCH THAT A GENERAL MODEL BLEND CAN BE
PREFERRED.
..SHORTWAVE CROSSING THE NORTHERN PLAINS THROUGH SUNDAY
..ENERGY THEN DIGGING THROUGH THE MIDWEST/OH VALLEY ON MONDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: NON-NAM BLEND
CONFIDENCE: ABOVE AVERAGE
A SHORTWAVE CURRENTLY OVER THE NORTHERN HIGH PLAINS WILL DIVE
SOUTHEAST ACROSS THE MIDWEST AND BE RACING ACROSS THE OH VALLEY BY
LATE MONDAY. IT WILL THEN REACH THE MID-ATLANTIC COAST MONDAY
NIGHT. THE 12Z NAM IS A STRONGER OUTLIER WITH THIS SYSTEM, AND SO
A NON-NAM BLEND WILL BE PREFERRED.
..SHORTWAVE CROSSING THE GREAT LAKES LATE MONDAY
..DROPPING DOWN ACROSS THE OH VALLEY ON TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z UKMET/ECMWF
CONFIDENCE: AVERAGE
IN THE WAKE OF THE SHORTWAVE ON MONDAY, A NEW NORTHERN STREAM
SHORTWAVE WILL DROP SOUTHEAST AND CROSS THE OH VALLEY ON TUESDAY.
THE 12Z CMC IS A STRONGER AND SLOWER OUTLIER SOLUTION WITH THIS
ENERGY. HOWEVER, THERE HAVE BEEN SOME GLOBAL MODEL TRENDS
(ESPECIALLY WITH THE NON-NCEP SOLUTIONS) TO BE STRONGER WITH THIS
ENERGY. IN FACT, THE 12Z NAM IS NOW SUDDENLY AMONG THE WEAKEST AND
MOST PROGRESSIVE SOLUTIONS, WITH THE 12Z GFS ONLY A LITTLE
SLOWER/DEEPER. THE 12Z UKMET AND 12Z ECMWF ARE REASONABLY WELL
CLUSTERED AND TEND TO BEST APPROXIMATE THE MODEL CONSENSUS IN
BETWEEN THE DEEP CMC AND WEAKER NAM/GFS, SO A BLEND OF THE UKMET
AND ECMWF WILL BE PREFERRED AT THIS POINT.
..SPLIT FLOW TROUGH CROSSING THE WEST COAST ON SUNDAY
..ENERGY EJECTING THROUGH THE SOUTHWEST AND PLAINS BY TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: BLEND OF THE 12Z NAM/GFS/ECMWF
CONFIDENCE: SLIGHTLY BELOW AVERAGE
THE MODELS ALL TAKE A PROGRESSIVE SPLIT-FLOW TROUGH ACROSS THE
WEST COAST ON SUNDAY, WITH A SOUTHERN STREAM PORTION OF THE ENERGY
THEN DROPPING DOWN ACROSS THE SOUTHWEST AND AMPLIFYING INTO A
CLOSED LOW AS IT APPROACHES THE SOUTHERN HIGH PLAINS BY EARLY
TUESDAY. MEANWHILE, THE NORTHERN STREAM COMPONENT OF THE TROUGH
WILL BE OVER THE NORTHERN HIGH PLAINS. THE 12Z CMC IS AN OUTLIER
WITH BOTH NORTHERN AND SOUTHERN STREAM COMPONENTS AS IT IS LIKELY
TOO STRONG/SLOW AND TOO FAR NORTH WITH THE SOUTHERN STREAM ENERGY,
AND TOO SLOW WITH THE ENERGY IN THE NORTHERN STREAM. THE 12Z UKMET
ALSO APPEARS TO BE TOO SLOW/DEEP WITH ITS HANDLING OF THE NORTHERN
STREAM ENERGY AND LIKE THE CMC TENDS TO SUPPORT A BIT MORE
INTERACTION BETWEEN NORTHERN AND SOUTHERN STREAM TROUGHS LATE IN
THE PERIOD. THE NAM/GFS AND ECMWF ALL FAVOR A BIT MORE STREAM
SEPARATION AT LEAST THROUGH THIS PERIOD WITH JUST SOME SUBTLE
NORTHERN/SOUTHERN STREAM TROUGH INTERACTION AT THE VERY END OF THE
PERIOD AS THE ENERGY APPROACHES THE MS VALLEY. WILL PREFER A BLEND
OF THE NAM/GFS AND ECMWF WITH BOTH STREAMS AT THIS TIME GIVEN THEY
STILL TEND TO HAVE THE STRONGER ENSEMBLE SUPPORT.
..PROGRESSIVE UPPER TROUGH OVER THE PACIFIC NORTHWEST TUESDAY
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
PREFERENCE: GENERAL MODEL BLEND
CONFIDENCE: AVERAGE
YET ANOTHER IN A SERIES OF PACIFIC SHORTWAVE TROUGHS WILL ARRIVE
ON TUESDAY ACROSS THE PACIFIC NORTHWEST. OVERALL, THE GUIDANCE HAS
TENDED TO TREND A LITTLE STRONGER WITH THIS SYSTEM, BUT THERE IS
BETTER AGREEMENT ON TIMING AND DEPTH. WILL PREFER A GENERAL MODEL
BLEND AT THIS POINT.
MODEL TRENDS AT WWW.WPC.NCEP.NOAA.GOV/HTML/MODEL2.HTML
500 MB FORECASTS AT WWW.WPC.NCEP.NOAA.GOV/H5PREF/H5PREF.SHTML
ORRISON
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