PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT WED APR 25 2007 6-10 DAY OUTLOOK VALID FOR MAY 01 - 05 2007 TODAYS GFS AND CANADIAN ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT AS THEY DEPICT A SHARP 500-HPA TROUGH NEAR THE CANADIAN MARITIMES... A BROAD 500-HPA TROUGH OVER THE WEST... AND A 500-HPA RIDGE IN BETWEEN THESE TWO TROUGHS. THE 12Z ECMWF SHOWS LESS PROGRESSIVE FLOW AS THE PAIR OF TROUGHS ARE FORECAST TO REMAIN ALONG BOTH COASTS. THE GFS AND CANADIAN ENSEMBLE MEAN SOLUTIONS INDICATE BELOW NORMAL 500-HPA HEIGHTS ACROSS THE PACIFIC NORTHWEST... WHILE THE 12Z ECMWF ENSEMBLE MEAN MAINTAINS ABOVE NORMAL 500-HPA HEIGHTS OVER THIS REGION. DUE TO THE GOOD AGREEMENT AMONG THE GFS-BASED AND 0Z CANADIAN ENSEMBLE MEAN SOLUTIONS... THE LESS PROGRESSIVE FLOW FORECAST BY THE 12Z ECMWF ENSEMBLE MEAN IS LIKELY AN OUTLIER TODAY. THE 0Z ECMWF HAS TRENDED AWAY FROM THE EARLIER FORECAST OF DEVELOPING A DEEP CUT-OFF LOW OVER TEXAS BUT ALL MODEL GUIDANCE SUGGESTS A WEAKNESS IN THE 500-HPA RIDGE ACROSS THE SOUTHERN TIER OF THE CONUS. IN ADDITION... A TREND TOWARDS A SPLIT-FLOW PATTERN ENTERING THE WESTERN CONUS HAS BECOME EVIDENT. MODEL GUIDANCE INDICATES A SERIES OF LOW-AMPLITUDE SHORTWAVE TROUGHS TRACKING ACROSS THE SOUTHERN TIER OF THE CONUS. THE OFFICIAL BLEND CHART DEPICTS ABOVE NORMAL 500-HPA HEIGHTS ACROSS MUCH OF THE CONUS EXCLUDING THE FLORIDA PENINSULA... SOUTH TEXAS... AND THE PACIFIC NORTHWEST. ABOVE NORMAL 500-HPA HEIGHTS SUPPORT ABOVE NORMAL TEMPERATURES FROM THE PLAINS TO THE EAST COAST. AS THE WEST COAST TROUGH MOVES INLAND... A COOLING TREND IS EXPECTED ACROSS THE ROCKIES. BELOW NORMAL TEMPERATURES ARE FORECAST FOR THE PACIFIC NORTHWEST AND ALASKAN PANHANDLE. WITH THE EXPECTED 500-HPA TROUGH AXIS ESTABLISHED OVER THE WEST... A WETTER-THAN-NORMAL WEATHER PATTERN IS ANTICIPATED FOR MUCH OF THE WESTERN AND CENTRAL CONUS. THE MID-LATITUDE JET WILL STEER SEVERAL SHORTWAVE TROUGHS FROM THE PACIFIC NORTHWEST INTO THE UPPER MIDWEST. THEREFORE... ABOVE NORMAL PRECIPITATION IS LIKELY OVER THE NORTHERN TIER OF THE ROCKIES AND PLAINS. THE GREATEST UNCERTAINTY IN THE PRECIPITATION FORECAST IS ASSOCIATED WITH THE SMALL AMPLITUDE SHORTWAVES IN THE SOUTHERN STREAM. ALTHOUGH MODEL GUIDANCE HAS BACKED AWAY FROM DEVELOPMENT OF A STRONG CUT-OFF LOW EARLY NEXT WEEK... WEAK SHORTWAVE TROUGHS COMBINED WITH ABUNDANT GULF MOISTURE COULD LEAD TO NEAR OR ABOVE NORMAL PRECIPITATION FOR THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. MEANWHILE... DRIER-THAN-NORMAL CONDITIONS ARE EXPECTED FROM THE SOUTHERN MID-ATLANTIC INTO GEORGIA AND FLORIDA. ELSEWHERE... BELOW NORMAL PRECIPITATION IS FORECAST FOR ALASKA. TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...40 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...AND 20 PERCENT OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8. MODEL(S) OF THE DAY: GFS SUPERENSEMBLE MEAN FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD IS ABOVE AVERAGE... 4 ON A SCALE OF 1 TO 5.... DUE TO GOOD AGREEMENT AMONG MOST OF THE ENSEMBLE MEAN SOLUTIONS. THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE KLEIN ... NEURAL NET AND ANALOG SPECIFICATIONS FROM THE OFFICIAL BLENDED HEIGHT FIELD... THE CPC AUTO TEMPERATURE FORECAST... THE CDC TEMPERATURE TOOL... AND KLEIN AND NEURAL NET PROBABLITIES FROM THE GFS ENSEMBLES. THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE ANALOG AND NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLENDED HEIGHT FIELD... THE CPC AUTO PRECIPITATION FORECAST... THE CDC PRECIPITATION TOOL... AND AN EXAMINATION OF THE DAILY PRECIPITATION FORECASTS FROM THE MODEL GUIDANCE. 8-14 DAY OUTLOOK FOR MAY 03 - 09 2007: THE LONGWAVE PATTERN DURING WEEK 2 IS QUITE SIMILAR TO THE 6-10 DAY PERIOD THOUGH LESS AMPLIFIED. THE REDUCED AMPLIFICATION IS A RESULT OF A LARGE ENSEMBLE SPREAD WHICH MAINLY REFLECTS A DIFFERENCE IN TIMING OF INDIVIDUAL CIRCULATION FEATURES. THE VARIOUS GFS AND 0Z CANADIAN ENSEMBLE MEAN SOLUTIONS INDICATE THAT A 500-HPA TROUGH WILL PUSH WELL OFF THE EAST COAST WHILE A BROAD TROUGH PERSISTS OVER THE WEST-CENTRAL CONUS. IT SHOULD BE NOTED THAT THE 0Z AND 6Z GFS ARE MORE AMPLIFIED WITH THE WESTERN TROUGH COMPARED TO THEIR RESPECTIVE ENSEMBLE MEAN SOLUTIONS. THE OFFICIAL BLENDED HEIGHT CHART INDICATES THAT 500-HPA HEIGHTS WILL REMAIN AT OR ABOVE NORMAL EXCLUDING SOUTH TEXAS... FLORIDA... AND THE PACIFIC NORTHWEST WHERE BELOW NORMAL 500-HPA HEIGHTS ARE FORECAST. SINCE ONLY MINOR CHANGES ARE NOTED IN THE EXPECTED LONGWAVE PATTERN FROM THE 6-10 DAY PERIOD... THE WEEK 2 TEMPERATURE AND PRECIPITATION FORECAST WILL BE SIMILAR WITH LOWER PROBABILITIES. ABOVE NORMAL TEMPERATURES SHOULD CONTINUE FROM THE MISSISSIPPI VALLEY TO THE EAST COAST BUT A WIDESPREAD AREA OF BELOW NORMAL TEMPERATURES ARE EXPECTED ACROSS THE WEST. DOWNSTREAM OF THE WESTERN TROUGH... THE STORMY WEATHER PATTERN WILL CONTINUE INTO WEEK 2 FOR THE PLAINS AND MISSISSIPPI VALLEY. A LARGE PART OF THE CONUS SHOULD RECEIVE ABOVE NOMRAL PRECIPITATION EXCEPT ALONG THE EAST COAST WHERE BELOW NORMAL PRECIPITATION IS FORECAST. ELSEWHERE... BELOW NORMAL PRECIPITATION WILL CONTINUE OVER PARTS OF ALASKA. THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...40 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...AND 20 PERCENT OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11. FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS ABOVE AVERAGE... 4 ON A SCALE OF 1 TO 5 DUE TO GOOD MODEL CONTINUITY AND GOOD AGREEMENT AMONG THE TEMPERATURE FORECAST TOOLS. THE 8-14 DAY TEMPERATURE PROG IS BASED ON THE ANALOG... NEURAL NET... AND KLEIN SPECIFICATIONS FROM THE OFFICIAL BLENDED HEIGHT FIELD... THE CPC AUTO TEMPERATURE FORECAST... AND THE CDC TEMPERATURE TOOL. THE 8-14 DAY PRECIPITATION PROG IS BASED ON THE ANALOG AND NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLENDED HEIGHT FIELD... THE CPC AUTO PRECIPITATION FORECAST... THE CDC PRECIPITATION TOOL... AND THE NEURAL NET PROBABILITIES FROM THE GFS AND CANADIAN ENSEMBLES. FORECASTER: NOTES: OPERATIONAL CHANGE: AS OF JULY 5 2005 SHADED MAPS HAVE REPLACED THE CONTOUR-ONLY MAPS ON THE CPC WEB SITE. THE CONTOURED MAPS ARE STILL AVAILABLE AT THEIR CURRENT FILE NAMES - SO DIRECT-LINKED USERS ARE NOT AFFECTED. AWIPS GRAPHICS ARE ALSO NOT AFFECTED BY THIS CHANGE. AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OTHERWISE - FORECASTS INCORPORATE FORECASTER INPUT. THE NOTATION FOR THE CATEGORICAL FORECAST INDICATED ON THE MAPS IS THE SAME AS THAT IN THE TABLES: A-ABOVE N-NEAR NORMAL B-BELOW IN THE SOUTHWEST AND OTHER CLIMATOLOGICALLY DRY REGIONS - THERE WILL BE A GREATER THAN 33.3% CHANCE OF NO PRECIPITATION AND OCCASIONALLY EVEN A NORMAL (I.E. MEDIAN) VALUE OF ZERO - ESPECIALLY DURING THE DRY SEASONS. IN SUCH CASES A FORECAST OF NEAR NORMAL IS EFFECTIVELY A FORECAST OF LITTLE OR NO PRECIPITATION. THE NARRATIVE DESCRIPTION OF THE FORECAST PATTERNS FOR TEMPERATURE AND PRECIPITATION FOR BOTH THE 6-10 OR 8-14 DAY PERIODS HAS BEEN DISCONTINUED. THE STATE TABLES FOR BOTH THE 6-10 AND 8-14 DAY PERIODS ARE NOW CONTAINED IN THIS MESSAGE...AVAILABLE AS PMDMRD ON AWIPS. THE CLIMATE PREDICTION CENTER USES 1971-2000 BASE PERIOD MEANS FOR TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN THE CLIMATE OUTLOOKS. THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON MAY 17. NEW NOTE EFFECTIVE MAR 16 2004: THE GLOSSARY FORMERLY FOUND AT THIS LOCATION WILL NO LONGER BE TRANSMITTED AS PART OF THIS MESSAGE. IF YOU WISH TO SEE THE DEFINITIONS OF TERMS USED IN THESE MESSAGES... PLEASE GO TO THE CPC WEB PAGE AT (USE LOWER CASE) HTTP://WWW.CPC.NCEP.NOAA.GOV AND FOLLOW THE APPROPRIATE LINKS. ANALOGS TO THE 5 DAY MEAN OBSERVED PATTERN CENTERED 3 DAYS AGO (D-3) FOR THE REGION FROM 20N to 70N LATITUDE AND 175E to 60W LONGITUDE INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES: 19690414 - 19690409 - 19930506 - 19920417 - 19930407 ANALOGS TO THE 7 DAY MEAN OBSERVED PATTERN CENTERED 4 DAYS AGO (D-4) FOR THE REGION FROM 20N to 70N LATITUDE AND 175E to 60W LONGITUDE INCLUDE THE 5 DAY PERIODS CENTERED ON THE FOLLOWING DATES: 19930406 - 19690414 - 19930412 - 19700416 - 19870407 6 to 10 day Outlook Table OUTLOOK FOR MAY 01 - 05, 2007 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF N N SRN CALIF N N IDAHO N A NEVADA A A W MONTANA N A E MONTANA A A WYOMING A A UTAH A A ARIZONA N N COLORADO A A NEW MEXICO N N N DAKOTA A A S DAKOTA A A NEBRASKA A A KANSAS A A OKLAHOMA A N N TEXAS A N S TEXAS N N W TEXAS N N MINNESOTA A A IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A N WISCONSIN A A ILLINOIS A A MISSISSIPPI A N MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A N ALABAMA A N NEW YORK A N VERMONT A N NEW HAMP A N MAINE A N MASS A N CONN A N RHODE IS A N PENN A N NEW JERSEY A N W VIRGINIA A N MARYLAND A N DELAWARE A N VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA A B FL PNHDL A B FL PENIN N B AK N SLOPE B N AK ALEUTIAN A N AK WESTERN A N AK INT BSN N B AK S INT A B AK SO COAST N B AK PNHDL B N 8 to 14 day Outlook Table OUTLOOK FOR MAY 03 - 09, 2007 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF N A SRN CALIF N N IDAHO B A NEVADA B A W MONTANA B A E MONTANA N A WYOMING N A UTAH B N ARIZONA N N COLORADO N N NEW MEXICO N N N DAKOTA N A S DAKOTA N A NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS A A S TEXAS N A W TEXAS A N MINNESOTA A A IOWA A A MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN A A ILLINOIS A A MISSISSIPPI A A MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A A ALABAMA A N NEW YORK A B VERMONT A B NEW HAMP A B MAINE A B MASS A B CONN A B RHODE IS A B PENN A B NEW JERSEY A B W VIRGINIA A N MARYLAND A B DELAWARE A B VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA A B FL PNHDL A B FL PENIN A B AK N SLOPE N N AK ALEUTIAN A B AK WESTERN N B AK INT BSN A N AK S INT A B AK SO COAST A B AK PNHDL B N LEGEND TEMPS WITH RESPECT TO NORMAL PCPN WITH RESPECT TO MEDIAN A - ABOVE N - NEAR NORMAL A - ABOVE N - NEAR MEDIAN B - BELOW B - BELOW THE FORECAST CLASSES REPRESENT AVERAGES FOR EACH STATE. NORMAL VALUES - WHICH MAY VARY WIDELY ACROSS SOME STATES - ARE AVAILABLE FROM YOUR LOCAL WEATHER SERVICE FORECAST OFFICE. FOR ADDITIONAL INFORMATION SEE MESSAGE FXUS06 KWBC - ON AWIPS AS PMDMRD. $$