777
FXUS02 KWBC 301757
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS HYDROMETEOROLOGICAL PREDICTION CENTER CAMP SPRINGS MD
156 PM EDT WED JUL 30 2008
VALID 12Z SAT AUG 02 2008 - 12Z WED AUG 06 2008
OVERALL MEAN FORECAST PATTERN OVER CONUS REMAINS THE SAME WITH A
MEAN TROF ALONG B.C AND THE PAC NW AND A MEAN TROF ALONG THE
CANADIAN MARITIMES AND NE COAST. RIDGING EXTENDS WWD FROM AFRICA
ACROSS THE ATLC THRU THE SOUTHEAST AND INTO THE PLAINS AND
SOUTHWEST.
GFS HAS ATROCIOUS CONTINUITY WITH ITS PRIOR TWO RUNS BEGINNING
SUNDAY DAY 4 AS IT HOLDS BACK A MID LEVEL LOW OVER WRN CANADA AND
BUILDS RIDGING OVER THE CENTRAL CANADIAN PLAINS AND DROPS
ADDITIONAL ENERGY INTO A NERN CONUS/ CAN MARITIME TROF. THIS
RESULTS IN REVERSING A 2.5 POSITIVE STANDARD DEVIATION MID LEVEL
RIDGE BUILDING OVER ERN CONUS INTO A NEG 2.5 STANDARD DEVIATION
TROF IN A 12 HR RUN CHANGE AS IT DROPS HTS 180 MTRS. THIS RESULTS
IN MOS TEMP VALUES DROPPING AS MUCH AS 15 DEGREES IN ONE 12 HR
RUN. GFS TRIED DOING THIS THE OTHER DAY OVER THE GREAT LAKES ONLY
TO REVERT BACK AGAIN. GFS ENS MEAN INDICATES THAT THE 00Z GFS ERN
TROF IS 60 MTRS TOO LOW WHILE ECMWF AND ITS MEAN INDICATE IT TO BE
ABOUT 90-120 MTRS TOO LOW. ECMWF HAS BETTER CONTINUITY DAYS 4-6.
06Z GFS ALREADY TRENDING 60+ MTRS HIGHER WITH ITS ERN CONUS TROF
THAN THE PRIOR 00Z RUN.
NEW 12Z GFS GOING BACK TO ITS ERN TROF 30 MTRS DEEPER THAN THE ITS
06Z RUN BUT REMAINS THE SAME ELSW. NEW UKMET/CMC AND 12Z GFS
ENSEMBLES ARE A BETTER MATCH TO ECMWF WITH HTS BACK CLOSER TO THE
06Z GFS RUN AND CLOSE TO THE 00Z ECMWF DAYS 6-8.
UPDATED HPC PRELIMS AND AFTN FINALS REMAIN SIMILAR TO EARLY
RELEASE USING A DOMINANT ECMWF WITH ADDITIONAL INPUT FROM THE
ECMWF ENS MEANS.
MONSOONAL RAINS WILL RETURN TO THE SOUTHWEST BEGINNING SUNDAY AS
UPPER LEVEL RIDGING BECOMES MORE FAVORABLE OVER THE AREA.
RAIN THREAT CONTS ALONG THE NE AND CENTRAL GULF COAST AS MOST
MODELS LEAVE BEHIND A MID LEVEL TROF/ CLOSED LOW THAT WILL WORK
WWD ACROSS THE GULF COAST TRIGGERING CONVECTION SAT TO MON.
MCS POTENTIAL ALONG THE SRN EDGE OF THE WESTERLIES NRN
PLAINS/UPPER MS VALLEY POSSIBLY INTO THE NORTH EAST MID TO LATE
NEXT WEEK.
HOT CONDS WILL CONT IN THE CENTRAL AND SRN PLAINS EXTENDING EWD
THRU THE LOWER OH AND TN VALLEYS AND THRU THE SOUTHEAST AND MID
ATLC REGIONS MON-WED. MID LEVEL H500 HTS ARE 1.5 TO 2 STANDARD
DEVIATIONS ABOVE NORMAL BUT H850 TEMP ANOMALIES ARE VERY HIGH
EXPANDING/SHIFTING FROM THE ROCKIES/PLAINS REGION SATURDAY TO THE
SOUTHEAST MONDAY THRU THURSDAY WHERE THEY ARE IN EXCESS OF 4-5
STANDARD DEVIATIONS ABOVE NORMAL. THIS WILL RESULT IN WIDESPREAD
TEMPS IN THE UPPER 90S AND INTO THE CENTURY MARK WITH SCATTERED TO
POSSIBLE WIDESPREAD RECORD TEMPS FROM THE CENTRAL MS/OH VALLEY
REGION INTO THE SOUTHEASTERN PIEDMONT AND UPPER COASTAL PLAIN.
ROSENSTEIN
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page