EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 1204 PM EDT TUE AUG 04 2015 VALID 12Z FRI AUG 07 2015 - 12Z TUE AUG 11 2015 ...GUIDANCE AND UNCERTAINTY ASSESSMENT... WPC MEDIUM RANGE SURFACE FRONTS/PRESSURES AND 500 MB PROGS ALONG WITH ASSOCIATED 2.5KM SENSIBLE WEATHER GRIDS HAVE BEEN PRIMARILY DERIVED FROM THE 00 UTC ECMWF ENSEMBLE MEAN. THIS ENSEMBLE MEAN SEEMED TO BEST FIT TRENDS/CLUSTERED DETAILS FROM DETERMINITSIC MODEL GUIDANCE THAT THEMSELVES SEEMINGLY OFFER TOO MUCH RUN TO RUN INCONSISTENCY FOR EXPLICIT INCLUSION. ...PATTERN OVERVIEW AND SENSIBLE WEATHER HIGHLIGHTS THREATS... IN THIS PATTERN....THE HEAVIEST RAINFALL POTENTIAL MAY WELL BE CONCENTRATED WITH A LOW EXPECTED TO LIFT/DEVELOP FROM THE MID-ATLANTIC FRI TO OFF NEW END AND INTO ERN CANADA THIS WEEKEND...ALONG WITH ACIVITY ALONG A TRAILING FRONT DUG DOWN THROUGH THE SERN US AND BACK OUT INTO THE CENTRAL PLAINS. THE LEAD LOW OFFERS LESS THAN STELLAR MODEL TO MODEL CONSISTENCY...ESPECIALLY RECENT GFS RUNS. THIS LEAVES OPEN POTENTIAL OF A TRACK MORE IN LINE WITH THE WET/UNSETTLED TUCKED IN ECMWF OR MORE OFFSHORE LIKE OTHER MODELS. THE WPC TRACK IS CLOSE OFFSHORE THE NERN US...BUT NOT AS INLAND AS THE 00 UTC ECMWF CONSIDERING ITS SUPPORTING MID-UPPER LEVEL TROUGH IS NOT MORE CLOSED. MEANWHILE...TRANSLATION OF STEADILY PROGRESSIVE NRN STREAM TROUGH ENERGIES WITH SOME AMPLITUDE FOR AUGUST OFFERS SOME TIMING UNCERTAINTIES...BUT FITS AN OVERALL PATTERN FAVORING SRN CANADIAN TO N-CENTRAL US...MIDWEST/GREAT LAKES...AND OH VALLEY/NERN US/MID-ATLANTIC FRONTAL SYSTEM PASSAGES THAT WILL FOCUS LOCALLY POTENT LEAD CONVECTION AND POST-FRONTAL COOLING. UPSTREAM...UNSEASONABLY DEEP MID-UPPER LEVEL TROUGHING DIGGING FROM OFF WRN CANADA TO JUST OFF THE PACIFIC NW/NRN CA SHOULD MEANWHILE ALLOW AN INLAND PCPN AND COOLING FRONTAL PUSH SUN-NEXT TUE. DOWNSTREAM...EXPECT MONSOONAL ACTIVITY TO CONTINUE AS MOISTURE FEED UP THROUGH THE SW AND INTERMOUNTAIN W/ROCKY STATES. SCHICHTEL