378
FXUS02 KWBC 071738
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
137 PM EDT SAT JUN 07 2008
VALID 12Z TUE JUN 10 2008 - 12Z SAT JUN 14 2008
MODELS ARE IN REASONABLY GOOD AGREEMENT THIS PERIOD WITH A
SHORTWAVE EXITING THRU THE GREAT LAKES REGION DAY 3 WHILE THE EAST
COAST RIDGE RECEDES SEAWARD. UPSTREAM GOOD AGREEMENT ON A STRONG
SHORTWAVE AND CLOSED MID LEVEL LOW COMING THRU WA DAY 3 ROTATING
EWD ACROS MT INTO ND DAYS 4 AND 5 AND LIFTING NEWD INTO MANITOBA
DAY 6 WITH A DEEP TROF EXTENSION INTO THE SOUTHWEST. UPSTREAM
DIFFICULTIES OCCUR IN THE NERN PACIFIC WITH THE NEXT SHORTWAVE
DROPPING SEWD OVER THE NERN PAC RIDGE. ECMWF IS STHE STRONGEST
HERE DAYS 5-7 TAKING A SECOND STRONG CLOSED LOW INTO WA FRI AND
NRN ROCKIES SAT. ALL OTHER MODELS INCLUDING ECMWF ENSEMBLES MORE
THAN SUGGEST THIS IS OVERDONE. GFS ENSEMBLE RELATIVE MEASURE OF
PREDICTABLITY INDICATES HIGH CONFIDENCE WITH THE LEAD DEEP CLOSED
LOW BUT LOW CONFIDENCE AND PREDICTABILITY WITH THIS FEATURE COMING
INTO THE PAC NW.
UPDATED HPC PRELIMS USED 00Z ECMWF DAYS 3 AND 4 TUES/WED BLENDING
IN THE ECMWF MEAN DAY 5 THURS AND BY FRI AND SAT ARE A BLEND OF
ECMWF AND GFS ENS MEAN.
12Z GFS RUN FOLLOWING REASONABLE CONTINUITY DAYS 3 TO 5 TUE-THURS.
HTS THRU THE PLAINS ARE ABOUT 30 MTRS DEEPER WITH THIS RUN ON DAY
6 FRI WHILE OFF THE CANADIAN MARITIMES IT IS MUCH DEEPER AND
SLOWER WITH A CLOSED LOW WHICH THEN DROPS SWD TO NR 40N 60W.
UPSTREAM THE NEW GFS RUN HAS FLATTENED THE UPSTREAM PAC NW/NRN
ROCKIES SHORTWAVE FROM ITS PRIOR RUN WHICH WAS AND IS A PREFERRED
HPC SOLUTION CLOSE TO THE ENS MEAN. 12Z GFS ENS MEAN DOES NOT
SUPPORT THE NWRN ATLC DEEP CLOSED LOW SYSTEM BUT IS REASONABLE AT
THIS TIME FRAME UPSTREAM ACROSS CONUS.
MINOR FRONTAL CHANGES TO PRIOR PRELIMS OTRW STAYING WITH EARLY
SOLUTION OF ECMWF DAYS 3-4 BLENDING IN ENSEMBLE MEANS 5-7.
ROSENSTEIN
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