MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 158 AM EST TUE JAN 10 2017 VALID JAN 10/0000 UTC THRU JAN 13/1200 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... 00Z NCEP MODEL EVALUATION INCLUDING INITIAL PREFERENCE AND FORECAST CONFIDENCE ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SURFACE CYCLOGENESIS OVER THE PLAINS INTO GREAT LAKES TUES/WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 10/00Z ECMWF/GFS BLEND CONFIDENCE: AVERAGE A BROAD LATITUDINAL WAVE CROSSING THE ROCKIES FRONT RANGE WILL CONTINUE TO MAKE ITS WAY TO THE MIDWEST AND GREAT LAKES FROM THROUGH WED. IT SPURS A LARGE AREA OF SURFACE CYCLOGENSIS. OVERALL THE NCEP MODELS WERE IN FAIRLY GOOD AGREEMENT...ALTHOUGH THE NAM TENDED TO HANDLE SHORTWAVE ENERGY SOMEWHAT DIFFERENTLY THAN THE GFS WHICH RESULTS IN A STRONGER SHORTWAVE TROF SPINNING UP TO THE LEE OF LAKE HURON LATE TUESDAY EVENING. THE GFS HAS CONSISTENTLY BEEN SPEEDING UP THE FORWARD SPEED OF THIS WAVE BUT OVERALL IT HAS BETTER RUN TO RUN CONSISTENCY THAN THE NAM. IN THE 00Z RUN...THE NAM SPUN UP A MUCH STRONGER VORT THAN OTHER OPERATIONAL RUNS FROM ITS OWN 09/12Z RUN. GIVEN THE NUMBER OF SMALL INTERNAL FEATURES/WAVES TO THE LARGE SYSTEM THERE REMAIN SMALLER SCALE DETAILS THAT REMAIN IMPORTANT THAT A LARGER BLEND WILL TAMP DOWN BUT ARE ALSO DIFFICULT TO PREDICT WITH HIGH CERTAINTY. AS SUCH A BLEND OF THE GFS WITH THE NAM/ECMWF HAS ONLY AVERAGE CONFIDENCE AS A WHOLE. CYCLONIC FLOW AND EMBEDDED SHORTWAVES SINKING ACROSS NORTHERN PLAINS ASSOCIATED FLAT SURFACE WAVE ACROSS GREAT LAKES EARLY THURS AND MORE COMPACT SURFACE WAVE CURVING THROUGH THE CANADIAN PRAIRIES THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~ PREFERENCE: 10/00Z NAM/GFS/UKMET BLEND CONFIDENCE: AVERAGE IN THE WAKE OF THE FIRST MAINLY PACIFIC WAVE AND SURFACE CYCLOGENESIS...BROAD CYCLONIC FLOW BEGINS TO EMERGE OUT OF CANADA WITH TWO SIGNIFICANT SHORTWAVE FEATURES. THE INITIAL CONDITIONS LEFT BY THE EXITING SHORTWAVE AS WELL AS HOW MUCH AND WHAT TIME SHORTWAVE ENERGY IS PHASED OUT OF THE PACIFIC STREAM LEAD TO MODERATE SPREAD OVERALL, PARTICULARLY IN THE STRENGTH/DEPTH OF THE TWO WAVES AND THEIR SPACING/TIMING. OVERALL THE 00Z NCEP RUNS WERE IN GOOD AGREEMENT WITH EACH OTHER AND STILL FIT ROUGHLY WHERE THEY HAD BEEN IN 12Z OPERATIONAL/ENSEMBLE RUNS. SAW NO REASON TO MAKE BIG CHANGES TO THE PREVIOUS MODEL CHOICES. THE 00Z NON NCEP MODELS WERE FUNDAMENTALLY THE SAME AS THEIR PREVIOUS RUNS SO SAW NO REAL REASON TO ALTER THE MODEL CHOICE. THE ONE EXCEPTION TO THAT WAS THE UKMET...WHOSE 00Z RUN GOT IT INTO BETTER AGREEMENT WITH THE NCEP RUNS. POTENT INNER CORE OF UPPER LOW REACHES THE WEST COAST TUESDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 10/00Z GFS/ECMWF/UKMET BLEND CONFIDENCE: SLIGHTLY ABOVE AVERAGE GOES WV MOSAIC STILL DENOTES VERY IMPRESSIVE INNER CORE OF THE UPPER LOW WEST OF THE WA/OR COAST. THIS WAVE WILL BE REPLACED AS THE HUB OF THE LARGER SCALE CYCLONE IN DUE TIME AS IT ROLLS EAST WITH ASSOCIATED SURFACE LOW MAKING LANDFALL NEAR THE MOUTH OF THE COLUMBIA RIVER LATER THIS COMING MORNING. THERE IS FAIRLY SOLID MODEL AGREEMENT WITH THIS SYSTEM AND EVOLUTION WITH RESPECT TO THE WEST COAST. THE 00Z NAM CONTINUED THE IDEA SHOWN BY PREVIOUS RUNS OF BEING A BIT DEEPER AND SLOWER TO WIND DOWN. AS A RESULT...THIS DIFFERENCE ALLOWS FOR GREATER INTERACTION WITH THE NORTHERN STREAM TROF WED/THURSDAY NOT SUPPORTED BY OTHER 12Z OPERATIONAL RUNS OF THE 00Z GFS. WILL CONTINUE TO KEEP IT FROM THE MODEL CHOICE AT THIS POINT. IN ADDITION...NOTHING IN HOW THE 00Z GFS EVOLVES THE SYSTEM GIVES ANY REASON TO RE-INTRODUCE THE 09/12Z UKMET AT THIS POINT. AS SUCH A BLEND OF THE 10/00Z GFS AND 09/12Z ECMWF BEST REPRESENTS THE MEAN. CONFIDENCE FOR THIS FEATURE INSIDE THE LARGER TROF IS AVERAGE. UNDERCUTTING SHORTWAVE AFFECTING N CA/SW OR LATE TUES INTO WED ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: NON CMC BLEND CONFIDENCE: AVERAGE A STRONG SHORTWAVE FROM THE CENTRAL PACIFIC RACES INTO THE EASTERN PACIFIC BY TUESDAY UNDER CUTTING THE WEAKENING UPPER LOW FEATURE. THIS WILL DIRECT DEEP MOISTURE FLUX AND ANOTHER BOUT OF FLOODING CONCERNS FOR N CA STARTING LATER TODAY AND PERSISTING INTO WEDNESDAY. THE ECMWF IS SLIGHTLY MORE SHALLOW AND SOMEWHAT FASTER IN THE MID-LEVELS COMPARED TO THE NAM/GFS WITH THE NAM/GFS ARE A BIT MORE VERTICALLY STACKED. THE 00Z NAM CAME IN WITH A STRONGER SOLN AND A CLOSED 546 DM CONTOUR WHERE AS BEFORE IT WAS AN OPEN WAVE WHICH PROPAGATED EASTWARD WHILE THE 00Z GFS CONTINUED TO SHOW A CLOSED MID LEVEL SYSTEM. THE 00Z ECMWF MADE A SHIFT TOWARDS THE IDEA OF CLOSING OFF A MID LEVEL CENTER LIKE OTHER RUNS FROM THE 00Z MODEL PRODUCTION CYCLE...SO IT CAN BE GIVEN AS MUCH CONSIDERATION AS ANY OTHER OF THE GLOBAL MODELS. REMAINING NORTHEAST TROF ENERGY SWINGING THROUGH THE WEST THURSDAY ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ PREFERENCE: 10/00Z GFS/ECMWF/CMC BLEND CONFIDENCE: AVERAGE WESTERN EXTENSION OF SHORTWAVE ENERGY IN THE DIGGING NORTHERN STREAM WEST OF THE COASTAL RANGE CAN BE SEEN BREAKING OFF NEAR HAIDA GWAII CURRENTLY. THERE IS FAIR MODEL AGREEMENT THAT THIS ENERGY WILL CONSOLIDATE AND LINGER OFFSHORE AS THE OVERALL LARGE SCALE TROF CONTINUES TO BREAK DOWN LATER TODAY AND WEDNESDAY. EVENTUALLY...THE VAST MAJORITY OF GLOBAL GUIDANCE AND ENSEMBLE MEMBERS DRAW THE WAVE SOUTH AND EAST TOWARD THE WEST COAST THURSDAY AS THE BASE OF THE LARGER SCALE TROF. THE MAIN EXCEPTION IS THE OLD UKMET WHICH SHOWING A BIT MORE STRENGTH IS INFLUENCED BY THE MEAN TROF LESS AND BREAKS OFF INTO A DEEP CONCENTRIC CLOSED LOW WELL OFFSHORE. SINCE THIS IS STILL 180 DEGREES OUT OF PHASE WITH THE 09/12Z RUN OF THE OPERATIONAL AND ENSEMBLE RUNS...IT REMAINS ONE OF THE MODELS NOT PREFERRED. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... BANN