MODEL DIAGNOSTIC DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1255 PM EDT WED JUL 09 2014 VALID JUL 09/1200 UTC THRU JUL 13/0000 UTC ...SEE NOUS42 KWNO (ADMNFD) FOR THE STATUS OF THE UPPER AIR INGEST... THERE DID NOT APPEAR TO BE ANY INITIALIZATION ERRORS WITH THE NAM/GFS DEEMED SIGNIFICANT ENOUGH TO IMPACT THEIR FORECASTS. ...UPPER TROF ANCHORING NORTHEASTERN NORTH AMERICA... ...SURFACE BOUNDARY EXITING THE NORTHEASTERN U.S... PREFERENCE: GENERAL MODEL COMPROMISE FORECAST CONFIDENCE: SLIGHTLY ABOVE AVERAGE A DEEP AND ANOMALOUS UPPER TROUGH TROF WILL SLOWLY CRAWL EASTWARD THROUGH THE ERN STATES THE REST OF THE WORK WEEK. A SERIES OF SHORTWAVE IMPULSES WILL WORK IN CONJUNCTION WITH AN ASSOCIATED SURFACE FRONT FOR SCATTERED SHOWERS/STORMS FROM THE MID-ATL AND SOUTHEAST INTO THE SOUTH. THE GUIDANCE IS OVERALL IN DECENT AGREEMENT WITH THE UPPER TROUGH/500MB HEIGHTS AND SLOW PROGRESSION OF THE SURFACE FRONT THURS THROUGH SAT... THOUGH SHORT WAVE DETAIL DIFFS TOUGHER TO DIAGNOSE. WPC WILL RECOMMEND A GENERAL MODEL BLEND/COMPROMISE OVER THE THREE DAYS. ...BROAD UPPER TROF MOVING ACROSS WESTERN INTO CENTRAL CANADA... ...SHORTWAVE SLIDING FROM THE NORTHERN PLAINS/UPPER MIDWEST TO EAST... PREFERENCE: BLEND OF THE GFS/ECMWF FOR MASS FIELDS/ECMWF FOR SHORT WAVE DETAILS FORECAST CONFIDENCE: AVERAGE MODELS DEPICT A DYNAMIC SYSTEM PROGRESSING FROM WRN TO CENTRAL CANADA ON THURS AND FRI BEFORE SETTLING OVER CENTRAL CENTRAL CANADA ON SAT AS A LARGE CLOSED UPPER LOW. THE ASSOCIATED SURFACE COLD FRONT WILL GRADUALLY PRESS SOUTH THROUGH MUCH OF THE UPPER MIDWEST... REACHING THE GREAT LAKES INTO THE MID MS VALLEY/CENTRAL PLAINS BY LATE SAT. JUST OUT AHEAD OF THE COLD FRONT AND SPECIFICALLY THE ASSOCIATED WARM FRONT... A SHORTWAVE ON THE NRN EXTENSION OF THE MONSOONAL CHANNEL NEAR NWRN NV/ERN OR WILL GET CAUGHT UP IN THE WESTERLIES. THIS FEATURE WILL TRACK ACROSS MT/WY THROUGH THE DAKOTAS WED TO THUR EVENING AND THE UPPER MS VALLEY INTO THE GREAT LAKES/WRN OH VALLEY BY FRI EVENING BEFORE SHEARING OUT DOWNSTREAM FOR SAT. THIS COULD BE A FAVORABLE ZONE ON THURS AND FRI FOR MORE CONCENTRATED CONVECTIVE HEAVY RAIN AREAS ALONG WITH THE TRAILING END OF THE SURFACE COLD FRONTAL ZONE. THE TAIL END OF THE FRONT WILL STALL ON SAT FROM THE CENTRAL PLAINS/MID MS VALLEY OR NEAR THE EDGE OF THE 500MB RIDGE CENTER... AS MORE MONSOONAL DYNAMICS EJECT FROM THE CENTRAL ROCKIES. WPC REALLY PREFERS THE MASS FIELDS OF THE ECMWF/GFS FOR THE FCST PERIOD BUT PREFER THE SHORT WAVE DETAILS OF THE ECMWF OVER THE GFS FRI INTO SAT. ...WEAK TROF OFFSHORE OF THE WEST COAST LATE IN THE PERIOD... PREFERENCE: BLEND OF GUIDANCE FORECAST CONFIDENCE: AVERAGE AN UPPER DISTURBANCE WELL OFFSHORE OF CA WILL BEGIN TO APPROACH CENTRAL/NRN CA LATE THURS BEFORE GRADUALLY LIFTING UP THE PAC NW COAST/INTERIOR NW FRI AND SAT. THE GUIDANCE OVERALL APPEARS TO HAVE A SOLID HANDLING ON THE PROGRESSION AND TRACK OF THIS SHORT WAVE IMPULSE THROUGHOUT THE FCST PERIOD ALONG WITH THE POTENTIAL ISOLATED TSTRM/DRY LIGHTNING ACTIVITY FROM NRN CA NORTHWARD INTO THE INTERIOR NW. www.wpc.ncep.noaa.gov/html/model2.shtml... www.wpc.ncep.noaa.gov/h5pref/h5pref.shtml... MUSHER