064
FXUS02 KWBC 281824
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
223 PM EDT SAT JUN 28 2008
VALID 12Z TUE JUL 01 2008 - 12Z SAT JUL 05 2008
ONLY MINOR CHANGES WERE MADE TO THE PRELIM GRAPHICS....WITH THE
12Z NCEP ENSEMBLE MEAN CONTINUING TO SHOW GOOD AGREEMENT IN THE
WAVE PATTERN TO THE ECMWF AND ECMWF ENSEMBLE MEAN. THE 12Z GFS
SHOWS A SLIGHTLY HIGHER AMPLITUDE IN THE EASTERN US TROUGH AND WAS
THE FINAL PROGS WERE NOT ADJUSTED TO MAINTAIN CONTINUITY. THE
ECMWF MEAN WAS PREFERRED DAYS 5-7 AS IT DID NOT BRING AS MUCH
HEIGHT FALLS INTO THE W COAST STATES THU-SAT DAYS 5-7.
CLIMATOLOGICALLY...WRN RIDGES ARE RESISTANT TO BEING BROKEN DOWN
DURING THE SUMMER MONTHS. THE 00Z/27 ECMWF MEAN/12Z GEFS MEAN
PRESERVES THE IDEA OF THE STRONG GREAT BASIN/NORTHERN ROCKIES HIGH
AMPLITUDE 500 MB RIDGE. THE 06Z/27 RUN OF THE OPERATIONAL GFS ALSO
SUPPORTED LESS 500MB HEIGHT FALL REACHING THE W COAST DAYS
5-6...ALTHOUGH IT DID SHOW SOME FALLS REACHING THE COAST BY DAY 7.
THE EARLY PRELIM DISCUSSION FOLLOWS BELOW.
LATEST MEDIUM RANGE MODELS CONTINUED TO SUPPORT A MEAN TROF OVER
ERN CANADA TO THE GREAT LAKES/MIDWEST. ADDITIONAL ENERGY WILL DIG
SEWD FROM CENTRAL CANADA TO REINFORCE THIS TROF...THOUGH ALL
GUIDANCE INDICATES THAT THE TROUGH WILL BE LESS AMPLIFIED BEYOND
DAY 3. USED A BLEND OF THE 00Z ECMWF AND THE 12Z EC MEAN ON DAYS
6-7 AS CONFIDENCE DIMINISHES DUE TO DIVERGENT MODEL SOLNS WITH THE
TIMING OF FEATURES SWINGING THRU THE BASE OF THE ERN CANADA TROF.
ELSEWHERE...A TROF SHOULD HOLD THRU THE GULF OF AK AND ERN
PAC...AND A STRONG RIDGE THROUGH THE INTERIOR WEST. THERE IS SOME
PATTERN PROGRESSION INDICATED BY THE 00Z ECMWF/GFS AND GLOBAL ENS
MEAN WITH HEIGHT FALLS OVER THE NORTHWEST BY DAYS 6-7 AS A PIECE
OF ENERGY CROSSES THE PAC NW INTO WRN CANADA.
..REGIONAL HIGHLIGHTS
TWO AREAS WILL HAVE THE LIMELIGHT THIS PERIOD REGARDING SENSIBLE
WEATHER. ONE WILL BE THE GULF COAST REGION AND FL.. THERE...AN
UNSEASONABLE COLD FRONT WILL SWEEP THE DEEPER MOISTURE ALL THE WAY
TO THE GULF COAST AND FL BY TUE....WHERE IT WILL LINGER THRU THU
BEFORE BEGINNING TO WORK BACK N NEXT WEEKEND. INDEED BOTH THE GFS
AND ECMWF SHOW THE FRONT ACTUALLY GETTING DOWN INTO THE NRN GULF
OF MEXICO...QUITE UNUSUAL FOR EARLY JULY. MOST OF THE SHOWERS THAT
OCCUR TUE-THU SHOULD BE CLOSE TO THE IMMEDIATE COASTLINE EXCEPT
FOR MORE GENERAL SHOWERS/STORMS OVER FL.
THE SECOND AREA BE IN CONNECTION WITH A SECOND FRONT WED-FRI THAT
WILL BE PUSHING SWD INTO THE MIDWEST AND GRT LAKES WED-FRI ON THE
SRN EDGE OF THE NEXT CANADIAN TROF. SOME LOCALLY HEAVY STORMS
COULD AGGRAVATE FLOODING PROBLEMS IN IA OR MO.
A THIRD MINOR AREA WILL BE THRU THE ROCKIES WHERE OCCASIONAL
MOSTLY NOCTURNAL MCS ACTIVITY WILL MOVE OFF THE MOUNTAINS DURING
THE AFTERNOONS INTO THE HIGH PLAINS AT NIGHT. THESE MCS CLUSTERS
WILL HAVE LOW MODEL PREDICTABILITY DAY BY DAY.
FLOOD/PETERSEN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page