MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 216 PM EST WED NOV 09 2016 VALID NOV 09/1200 UTC THRU NOV 13/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... ...AN EVALUATION OF THE 12Z MODEL GUIDANCE ALONG WITH FINAL PREFERENCES/FORECAST CONFIDENCE... ...PAIR OF SHORTWAVES MOVING OFF THE EASTERN SEABOARD TONIGHT... ...SURFACE CYCLONE EXITING THE MID-ATLANTIC COAST... FINAL PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: ABOVE AVERAGE WATER VAPOR IMAGERY THIS AFTERNOON SHOWED A PAIR OF SYSTEMS CROSSING THE MID-ATLANTIC AND SOUTHERN QUEBEC...RESPECTIVELY. A BROAD SWATH OF LIGHT TO LOCALLY MODERATE RAINFALL HAS ACCOMPANIED THE FORMER WAVE WITH THIS SYSTEM EVENTUALLY EXITING THE NC OUTER BANKS BY 10/0600Z. THE UNCERTAINTY WHICH WAS NOTED IN THE OFFSHORE WATERS HAS DECREASED MARKEDLY WITH THE ARRIVAL OF THE 12Z MODEL SUITE AS THE 12Z CMC TRENDED SLOWER. THIS BROUGHT IT BACK CLOSER TO THE CONSENSUS. AS SUCH...A GENERAL MODEL COMPROMISE APPEARS WARRANTED. ...QUASI-STATIONARY UPPER LOW LINGERING OVER NORTHERN MX... ...INVERTED SURFACE TROUGH OVER THE FAR WESTERN GULF OF MX... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF FORECAST CONFIDENCE: AVERAGE A SOUTHWEST-NORTHEAST ORIENTED UPPER TROUGH CURRENTLY EXTENDING FROM CENTRAL MX INTO TX WILL CONTINUE RETROGRADING BACK TOWARD FAR WEST TX/NORTHERN MX. EVALUATING THE ENSEMBLE SPAGHETTI PLOTS FROM THE PAST FOUR MODEL CYCLES...THE NORTHEASTWARD JOG THE PREVIOUS 00Z GEFS MEMBERS DEPICTED APPEARED TO BE AN OUTLIER AS MORE RECENT RUNS PULLED BACK TOWARD THE CONSENSUS. LOOKING AHEAD TO 12/0000Z...THE 00Z ENSEMBLES HAVE ALL MOVED TOWARD A QUICKER LIFTING OF THE UPPER LOW BACK TOWARD SOUTHERN NM. ALTHOUGH THE 12Z NAM CAME IN EVEN FURTHER TOWARD THE NORTHEAST RELATIVE TO MOST SOLUTIONS. CONSIDERING THE SURFACE PATTERN EAST OF THE UPPER LOW...THE 12Z NAM/CMC WERE ALSO MUCH MORE AGGRESSIVE IN DEPICTING A CYCLONIC CIRCULATION WHICH DOES NOT HAVE A WHOLE LOT OF SUPPORT THUS FAR. GIVEN THE ABOVE ASSESSMENT...WPC FAVORS A COMBINATION OF THE 12Z GFS/ECMWF. ...PROGRESSIVE SHORTWAVE CURRENTLY PUSHING INTO COASTAL WA... ...EVENTUAL AMPLIFIED FLOW CROSSING THE GREAT LAKES/NORTHEASTERN U.S. ON FRIDAY/SATURDAY... ...ACCOMPANYING COLD FRONT... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF FORECAST CONFIDENCE: SLIGHTLY BELOW AVERAGE MODEST HEIGHT FALLS CROSSING THE WA COAST WILL TRACK ATOP A STOUT UPPER RIDGE ANCHORING THE INTERMOUNTAIN WEST/ROCKY MOUNTAIN REGION. THIS CARRIES THE SHORTWAVE ENERGY INTO SOUTHERN ALBERTA/SASKATCHEWAN WHILE ADJOINING A STRONGER LONGWAVE TROUGH ACROSS CENTRAL CANADA. NOTABLE SPREAD DOES NOT SHOW UP UNTIL ROUGHLY FRIDAY EVENING WITH MANY OF THE 00Z GEFS MEMBERS BEING SLOWER RELATIVE TO THE DOWNSTREAM CLUSTER. THIS DOES LEAD TO FURTHER UNCERTAINTIES AS THE SOUTHWESTERN FLANK OF THE TROUGH TRAVERSES THE MID-SOUTH/CAROLINA REGION. THERE CONTINUES TO BE A LOT OF RUN-TO-RUN UNCERTAINTIES AMONG THE SOLUTIONS WITH THE 12Z CMC BECOMING THE SLOWEST FORECAST AFTER THE PREVIOUS RUN WAS THE QUICKEST. ADDITIONALLY...THERE ALSO REMAINS A DIVIDE BETWEEN THE 12Z GFS/ECMWF CAMPS WITH TIMING DIFFERENCES WITH THE NORTHERN EXTENT OF THE TROUGH EXITING NEW ENGLAND AS WELL AS THAT PINCHING OFF OVER THE SOUTHEASTERN U.S. WILL CONTINUE TO SPLIT THE DIFFERENCE BETWEEN THIS PAIR OF SOLUTIONS ALTHOUGH PLAN ON BACKING OFF ON THE USE OF ENSEMBLE MEANS FOR DAY 3. THIS IS DUE TO THE FACT THE 00Z ECMWF ENSEMBLE MEAN APPEARS TO BE MUCH QUICKER THAN ALL OF THE 12Z DETERMINISTIC FORECASTS. ...NEXT PACIFIC SYSTEM REACHING THE NORTHWESTERN U.S. COAST BY 12/0600Z... FINAL PREFERENCE: BLEND OF THE 12Z GFS/ECMWF FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE A SHARP BAND OF HEIGHT FALLS NEARING 130W ON FRIDAY MORNING WILL EVENTUALLY AFFECT THE PACIFIC NORTHWEST COAST BETWEEN 12/0000Z AND 12/0600Z. SIMILAR TO YESTERDAY...THE 12Z CMC ADJUSTED FROM ITS PREVIOUS OUTLYING FORECAST WHICH BRINGS IT CLOSER TO THE REST OF THE PACK. AS THE SYSTEM TRANSLATES INLAND...THE 12Z GFS TRENDED SLOWER AS DID THE 12Z ECMWF. PLAN ON FOLLOWING THIS NEW TREND AND BLEND THE TWO SOLUTIONS TOGETHER. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... RUBIN-OSTER