EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
1138 AM EDT FRI JUN 14 2013

VALID 12Z MON JUN 17 2013 - 12Z FRI JUN 21 2013

...OVERVIEW AND PREFERENCES...

MEDIUM RANGE GUIDANCE MAINTAINS BETTER THAN AVERAGE
AGREEMENT/CONTINUITY FOR LARGE SCALE FLOW... CONSISTING OF AN ERN
PAC CLOSED LOW/AMPLIFIED TROUGH ALOFT MOVING INTO THE WEST WHILE A
ROCKIES RIDGE BUILDS INTO THE PLAINS/MS VALLEY AND TROUGHING
SETTLES OVER THE EAST.  CURRENT INDICATIONS ARE THAT THE PLAINS/MS
VLY RIDGE MAY STRENGTHEN LATE NEXT WEEK WHILE THE TWO MEAN TROUGHS
WEAKEN A LITTLE.  FOR DAYS 3-5 MON-WED... OPERATIONAL MODELS STILL
VARY WITH LOW PRES FCST TO BRUSH NRN NEW ENGLAND BUT AN AVERAGE OF
00Z ECMWF/00Z-06Z GFS RUNS AND TO A LESSER EXTENT 00Z UKMET
PROVIDES A GOOD INTERMEDIATE SOLN THAT IS BETTER DEFINED THAN THE
ENSEMBLE MEANS.  THIS SOLN REPRESENTS CONSENSUS FOR THE SYSTEM
MOVING INTO THE WEST.  BY DAYS 6-7 THU-FRI PREFER TO LEAN 2/3
TOWARD THE 00Z ECMWF MEAN VERSUS THE 06Z OR 00Z GEFS MEAN AS
RECENT CONTINUITY HAS HEDGED A LITTLE SLOWER... WHILE FOR THE ERN
TROUGH ALOFT THIS SOLN LIES BETWEEN THE MORE AMPLIFIED 00Z ECMWF
AND FLATTER 00Z/06Z GFS. 


...GUIDANCE EVALUATION...

MODELS CONTINUE TO VARY WITH THE HANDLING OF SHRTWV ENERGY OVER
THE NERN CONUS/SERN CANADA DURING THE FIRST HALF OF THE PERIOD...
AND THUS DIFFER WITH SFC EVOLUTION.  ON THE GOOD SIDE
MODELS/ENSEMBLES HAVE IMPROVED THEIR CLUSTERING AT THE SFC
SOMEWHAT OVER THE PAST DAY AND NOW INDICATE LOW PRES TRACKING OVER
OR JUST N OF NRN NEW ENGLAND.  THE 00Z ECMWF IS A LITTLE SLOWER
THAN ITS ENSEMBLE MEAN AND 00Z/06Z GFS RUNS ARE FASTER THAN THEIR
MEANS.  THE 00Z UKMET MAY BE A LITTLE TOO WRAPPED UP WITH ITS
SYSTEM.  TYPICAL BIASES ARGUE FOR AN INTERMEDIATE SOLN FOR TIMING
THOUGH ENOUGH OPERATIONAL SIGNAL EXISTS FOR A BETTER DEFINED
SYSTEM THAN FCST BY THE MEANS.  THE FAVORED OPERATIONAL BLEND INTO
DAY 5 YIELDS SUCH A SOLN.

FOR THE MOST PART SOLNS HAVE BEEN MORE CONSISTENT/AGREEABLE THAN
AVG WITH THE CLOSED LOW TRACKING INTO THE NORTHWEST AND TROUGH
EXTENDING TO ITS S.  WHAT TRENDS EXIST OVER THE PAST FEW RUNS OF
GFS/GEFS MEAN/ECMWF/ECMWF MEAN RUNS ARE ON THE SLOWER SIDE...
FAVORING 2/3 WEIGHTING OF THE ECMWF MEAN THAT BECOMES A LITTLE
SLOWER WITH THE CORE OF MID LVL ENERGY BY LATE NEXT WEEK.  AMONG
LATEST RUNS BY DAY 7 FRI THE 00Z GFS AND FARTHER SWD 00Z CMC MAY
BE A LITTLE FAST WITH THE MID LVL CLOSED LOW WHILE THE 06Z GFS
TRACKS FARTHER SWD THAN CONSENSUS.

WHILE THE FCSTS FOR THE MEAN FEATURES OVER THE CONUS HAVE BEEN
FAIRLY STABLE... THERE HAS BEEN MORE SPREAD/DAILY VARIABILITY IN
SOME DETAILS OF FLOW ACROSS THE NERN PAC/ALASKA AND CANADA.  IN
SOME SOLNS THIS HAS HAD SOME INFLUENCE ON NRN LATITUDES OF THE
CONUS.  OF NOTE THIS CYCLE THE 06Z GFS LOWERS HGTS MORE THAN
CONSENSUS BETWEEN THE GRTLKS AND HUDSON BAY... BY DAY 7 LEADING TO
A FARTHER SEWD EXTENT OF A SRN CANADA FRONT AND MORE SUPPRESSED
SFC PATTERN OVER THE NRN PLAINS AS WELL.  THE 00Z ECMWF IS ON THE
FASTER SIDE OF THE SPREAD WITH CLOSED LOW ENERGY TRACKING TO THE N
OF HUDSON BAY.


...SENSIBLE WEATHER HIGHLIGHTS...

DURING THE FIRST HALF OF NEXT WEEK EXPECT SOME LOCALLY HVY AREAS
OF CONVECTION ALONG AN ERN CONUS COLD FRONT TRAILING FROM EXTREME
NERN CONUS/SERN CANADA LOW PRESSURE.  THIS FRONT SHOULD STALL OVER
THE SOUTH AND NWWD INTO THE PLAINS... SERVING TO FOCUS SOME
LINGERING ACTIVITY IN ITS VICINITY.  BY LATE IN THE WEEK ANY
PLAINS CONVECTION SHOULD TAPER OFF AS THE BNDRY BEGINS TO LIFT
NEWD AS A WARM FRONT WHILE DIURNALLY ENHANCED RNFL OVER THE
SOUTHEAST SHOULD CONTINUE THROUGH THE END OF THE WEEK.  SYSTEM
MOVING INTO THE WEST WILL BRING MULTIPLE DAYS OF RNFL INTO THE
NORTHWEST/NRN ROCKIES AND EVENTUALLY PORTIONS OF THE NRN PLAINS. 
THE MOST PRONOUNCED TEMPERATURE ANOMALIES SHOULD BE SEEN MID-LATE
WEEK... APPROX FROM THE NRN HALF OF THE WEST INTO THE NRN HIGH
PLAINS ON THE COLD SIDE AND CNTRL-SRN HIGH PLAINS ON THE WARM
SIDE.  IN BOTH CASES SOME LOCATIONS MAY SEE 10-15 F DEPARTURES
FROM NORMAL FOR DAYTIME HIGHS.

RAUSCH