EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 235 AM EDT WED JUL 23 2014 VALID 12Z SAT JUL 26 2014 - 12Z WED JUL 30 2014 ...OVERVIEW AND GUIDANCE EVALUATION/PREFERENCES... GUIDANCE CONTINUES TO SUGGEST WELL ABOVE AVERAGE CONFIDENCE IN THE DEVELOPMENT OF A VERY AMPLIFIED WRN RIDGE/ERN TROUGH PATTERN. MOST MODEL/ENSEMBLE MEAN RUNS SHOW AN AREA OF MID LVL HGT ANOMALIES EXCEEDING 2 STDEVS BELOW NORMAL SETTLING INTO THE OH VLY/CNTRL APLCHNS REGION FOR AT LEAST A PART OF THE LATTER HALF OF THE PERIOD. HGT ANOMALIES IN THE SRN PART OF THE UPR HIGH FCST TO BE CNTRD OVER THE SRN ROCKIES MAY EXCEED 2 STDEVS ABOVE NORMAL AS WELL. WHILE THERE IS REMARKABLY GOOD AGREEMENT IN THE RESULTING MEAN PATTERN BY THE LATTER HALF OF THE PERIOD... SOME QUESTION MARKS REMAIN IN THE ROUTE TAKEN TO GET THERE. IN PARTICULAR THERE IS STILL NOTABLE TIMING SPREAD IN THE SEWD PROGRESSION OF ENERGY ASSOC WITH THE COMPACT UPR LOW JUST N OF THE NRN PLAINS AS OF THE START OF THE PERIOD EARLY SAT. ON THE POSITIVE SIDE THERE APPEARS TO BE SOME CONVERGENCE TOWARD THE IDEA OF MAINTAINING REASONABLE DEFINITION TO THE ENERGY AS IT DROPS SEWD TOWARD THE GRTLKS VERSUS HAVING IT SHEARED AS SPORADICALLY FCST BY SOME PRIMARILY NON-GFS MODEL RUNS. GFS RUNS HAVE TENDED TO BE IN THE FASTER PART OF THE ENVELOPE AND THE ECMWF SLOWER. AS AMPLIFICATION TAKES PLACE IN THE FIRST HALF OF THE PERIOD THE SFC PATTERN MAY BE SOMEWHAT AMORPHOUS WITH MULTIPLE SFC LOWS THOUGH FAVORING BEST DEFINITION OVER THE GRTLKS. LOW PRESSURE IS EXPECTED TO CONSOLIDATE/STRENGTHEN AS IT LIFTS NEWD FROM THE GRTLKS MON-WED. PREFER AN EVEN WEIGHTING OF OPERATIONAL MODEL DETAIL AND AGREEABLE LARGER SCALE EVOLUTION OF THE ENSEMBLE MEANS. INITIAL TIMING OF THE 18Z GFS IS LESS EXTREME THAN THE 12Z RUN SO THE 18Z GFS/12Z ECMWF SOLNS ARE BLENDED WITH THE 18Z GEFS/12Z ECMWF MEANS. THE NEW 00Z GFS/UKMET/CMC FALL IN THE MIDDLE TO FASTER HALF OF THE SPREAD WITH THE INITIAL UPR LOW AND COMPARE FAIRLY WELL TO ESTABLISHED CONSENSUS BY DAY 5 MON. GIVEN STRENGTH OF THE WRN CONUS-CNTRL CANADA RIDGE... SLOWER STILL LOOKS BETTER WITH THE UPR LOW DRIFTING OVER THE NERN PAC. BLENDING THE ENSEMBLE MEANS WITH THE 18Z GFS/12Z ECMWF HELPS TO TONE DOWN HGT FALLS NEARING THE PAC NW COAST DAY 7 WED IN THE LATTER SOLNS. STILL THEY ARE MUCH CLOSER TO THE MEANS THAN THE VERY PROGRESSIVE 12Z GFS. ...SENSIBLE WEATHER HIGHLIGHTS... EXPECT COOLER TEMPS TO SPREAD SEWD FROM THE NRN TIER DURING THE PERIOD... LEAVING MUCH OF THE ERN 2/3 OF THE CONUS WITH BELOW AVERAGE READINGS BY THE MIDDLE OF NEXT WEEK. IN GENERAL MAX TEMPS SHOULD BE SOMEWHAT FARTHER BELOW NORMAL THAN THE MINS THOUGH IN MOST CASES LIKELY NOT AS EXTREME AS WITH THE PREVIOUS SURGE OF COOL AIR. AHEAD OF THIS COOLING TREND ONE OR MORE SFC LOWS/FRONTAL SYSTEMS WILL SUPPORT AREAS OF RNFL/TSTMS OVER THE ERN THIRD OF THE CONUS FROM THE WEEKEND INTO EARLY NEXT WEEK... SETTLING TOWARD THE SERN/GULF COAST THEREAFTER. SOME LINGERING ACTIVITY MAY CONTINUE FOR A TIME IN THE VICINITY OF THE GRTLKS NEAR THE CORE OF THE UPR TROUGH. MEANWHILE LOW LVL UPSLOPE FLOW BEHIND THE TRAILING PART OF THE MAIN SFC FRONT MAY INCREASE POTENTIAL FOR LOCALLY HVY RNFL OVER PORTIONS OF CO/NM. OVER THE INTERIOR WEST... TEMPS SHOULD BE NEAR TO ABOVE NORMAL WITH HIGHEST ANOMALIES TENDING TO BE OVER THE NORTHWEST. EXPECT MOST CONVECTION TO BE ON THE LGT/SCT SIDE. RAUSCH