PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT FRI APR 11 2008 6-10 DAY OUTLOOK VALID FOR APR 17 - 21 2008 TODAYS ENSEMBLE MEAN SOLUTIONS ARE IN BETTER AGREEMENT FOR THE 6-10 DAY PERIOD, AND THERE IS LESS SPREAD AMONG INDIVIDUAL ENSEMBLE MEMBERS, COMPARED TO THE LAST COUPLE DAYS FORECASTS. THE 12Z ECMWF ENSEMBLE MEAN FORECASTS A RELATIVELY SHALLOW AND BROADER TROUGH OVER WESTERN NORTH AMERICA THAN THE GFS-BASED ENSEMBLES. TODAYS 0Z AND 6Z GFS ENSEMBLE MEANS AND THE 0Z GFS OPERATIONAL MODEL INDICATE BELOW NORMAL 500-HPA HEIGHTS AS FAR SOUTH AS SOUTHERN CALFORNIA LEADING TO SOMEWHAT COOLER TEMPERATURES FOR PARTS OF THE SOUTHWEST THAN THE ECMWF AND CANADIAN ENSEMBLE MEAN SOLUTIONS. THE ECMWF, CANADIAN AND GFS ENSEMBLE MEANS GENERALLY HAVE RIDGING OVER THE EASTERN HALF OF THE CONUS WITH GREATER 500-HPA HEIGHTS IN THE GFS-BASED ENSEMBLE MEANS THAN THE ECMWF AND CANADIAN ENSEMBLE MEANS. THE 0Z AND 6Z GFS AND 12Z AND 0Z ECMWF HIGH RESOLUTION RUNS ALL FORECAST A MORE AMPLIFIED EASTERN RIDGE RELATIVE TO THE VARIOUS ENSEMBLE MEAN SOLUTIONS PARTLY DUE TO DIFFERENCES IN INDIVIDUAL ENSEMBLE MEMBERS. THE 0Z AND 6Z GFS ENSEMBLE MEAN SOLUTIONS ARE WELL CORRELATED WITH THEIR ANALOGS AND ARE WEIGHTED MORE IN THE OFFICIAL 500-HPA HEIGHT BLEND. ABOVE NORMAL MEAN TEMPERATURES ARE FORECAST FROM NEW MEXICO AND WEST TEXAS NORTHEASTWARD THROUGH THE CENTRAL PLAINS INTO THE NORTHEASTERN QUARTER OF THE U.S. BELOW NORMAL UPPER-LEVEL HEIGHTS WEST OF THE ROCKIES AND OVER THE FLORIDA PENNINSULA FAVOR BELOW NORMAL TEMPERATURES FOR THESE REGIONS. UPPER-LEVEL LOWS THAT FORM AHEAD OF THE WESTERN TROUGH SHOULD PRODUCE ABOVE NORMAL PRECIPITATION FROM THE CENTRAL AND NORTHERN PLAINS EASTWARD INTO THE MIDWEST STATES. PRECIPITATION EARLY IN THE PERIOD AHEAD OF THE PACIFIC JET SHOULD LEAD TO ABOVE NORMAL PRECIPITATION FOR PARTS OF THE PACIFIC NORTHWEST. MEAN TEMPERATURES FOR MOST OF ALASKA SHOULD BE BELOW NORMAL UNDER BELOW NORMAL HEIGHTS AND ANOMALOUS NORTHWESTERLY FLOW, EXCEPT FOR THE ALEUTIONS WHICH SHOULD BE NEAR NORMAL. WESTERN ALASKA AND THE ALASKAN PANHANDLE ARE EXPECTED TO RECIEVE ABOVE NORMAL PRECIPITATION FOR THE PERIOD ALONG THE MEAN STORM TRACK. TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...40 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...AND 40 PERCENT OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8. MODEL(S) OF THE DAY: 6Z GFS ENSEMBLE MEAN AND 12Z ECMWF ENSEMBLE MEAN FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD IS BELOW AVERAGE... 2 ON A SCALE OF 1 TO 5 DUE TO ONLY FAIR AGREEMENT BETWEEN THE ECMWF, CANADIAN AND GFS ENSEMBLE MEAN SOLUTIONS AND SIGNIFICANT DIFFERENCES IN THE EXPECTED TEMPERATURE AND PRECIPITATION PATTERNS. THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTO FORECAST, KLEIN AND ANALOG SPECIFICATIONS OF THE OFFICIAL BLEND AND VARIOUS MODELS, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE GUIDANCE, AND THE CDC REFORECAST TEMPERATURE GUIDANCE. THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE CPC AUTO FORECAST, ANALOG SPECIFICATIONS OF THE OFFICIAL BLEND AND VARIOUS MODELS, DAILY PRECIPITATION PROBABILITIES FROM THE 0Z GFS AND CANADIAN ENSEMBLES, AND THE CDC REFORECAST PRECIPITATION GUIDANCE. 8-14 DAY OUTLOOK FOR APR 19 - 25 2008: THE FORECAST 8-14 DAY UPPER LEVEL FLOW PATTERN IS SOMEWHAT SIMILAR TO THAT FORECAST FOR THE 6-10 DAY PERIOD, WITH A RIDGE OVER THE EASTERN CONUS AND A TROUGH OVER THE WESTERN CONUS. 500-HPA HEIGHTS OVER THE U.S. SOUTHWEST ARE SOMEWHAT LOWER IN THE 8-14 DAY PERIOD. THE RESULTING TEMPERATURE AND PRECIPITATION PATTERNS ARE THEREFORE SOMEWHAT SIMILAR IN THE 6-10 AND 8-14 DAY PERIODS. THE AREA OF EXPECTED BELOW NORMAL MEAN TEMPERATURES IN THE WEST HAS EXPANDED EASTWARD OF THE ROCKIES INTO THE HIGH PLAINS. ABOVE NORMAL MEAN TEMPERATURES ARE LESS LIKELY IN THE SOUTHERN PLAINS IN THE 8-14 DAY PERIOD THAN THE 6-10 DAY PERIOD AND MOST PROBABLE FROM THE MISSISSIPPI VALLEY EASTWARD. ABOVE NORMAL PRECIPITATION IS LIKELY EAST OF THE TROUGH OVER THE WESTERN CONUS, PRIMARILY OVER THE NORTHERN AND CENTRAL PLAINS INTO THE WESTERN GREAT LAKES REGION. THE PACIFIC NORTHWEST COAST AND U.S. SOUTHWEST SHOULD BE DRY, AS WELL AS THE GULF COAST STATES NORTHEASTWARD INTO THE MIDDLE ATLANTIC COAST STATES. WESTERN ALASKA, THE ALEUTIANS AND THE ALASKAN PANHANDLE SHOULD CONTINUE TO SEE ABOVE NORMAL RAINFALL AMOUNTS IN THE 8-14 DAY PERIOD. THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...40 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...AND 40 PERCENT OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11. FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS BELOW AVERAGE... 2 ON A SCALE OF 1 TO 5 DUE TO FAIR AGREEMENT BETWEEN THE CANADIAN AND GFS ENSEMBLE MEAN UPPER-LEVEL HEIGHT PATTERNS, AND SOME DISAGREEMENT AMONG THE TEMPERATURE AND PRECIPITATION TOOLS. THE 8-14 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTO FORECAST, KLEIN AND ANALOG SPECIFICATIONS OF THE OFFICIAL BLEND AND VARIOUS MODELS, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE GUIDANCE, AND THE CDC REFORECAST TEMPERATURE GUIDANCE. THE 8-14 DAY PRECIPITATION PROG IS BASED ON THE CPC AUTO FORECAST, ANALOG SPECIFICATIONS OF THE OFFICIAL BLEND AND VARIOUS MODELS, DAILY PRECIPITATION PROBABILITIES FROM THE 0Z GFS AND CANADIAN ENSEMBLES, AND THE CDC REFORECAST PRECIPITATION GUIDANCE. FORECASTER: D. COLLINS 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 APRIL 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: 19880331 - 19760329 - 19730418 - 19810404 - 19880326 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: 19880331 - 19810404 - 19760329 - 19550415 - 19730418 6 to 10 day Outlook Table OUTLOOK FOR APR 17 - 21, 2008 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B A OREGON B A NRN CALIF B N SRN CALIF B N IDAHO B N NEVADA B N W MONTANA B N E MONTANA N N WYOMING N N UTAH B N ARIZONA N B COLORADO N B NEW MEXICO A B N DAKOTA N A S DAKOTA N A NEBRASKA A A KANSAS A A OKLAHOMA A A N TEXAS A N S TEXAS N B W TEXAS A B MINNESOTA A A IOWA A A MISSOURI A A ARKANSAS A N LOUISIANA N B WISCONSIN A A ILLINOIS A A MISSISSIPPI N B MICHIGAN A A INDIANA A A OHIO A A KENTUCKY A N TENNESSEE A N ALABAMA N B NEW YORK A A 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 B W VIRGINIA A N MARYLAND A B DELAWARE A B VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA N B FL PNHDL B B FL PENIN B B AK N SLOPE B B AK ALEUTIAN N A AK WESTERN B A AK INT BSN B N AK S INT B N AK SO COAST B A AK PNHDL B A 8 to 14 day Outlook Table OUTLOOK FOR APR 19 - 25, 2008 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B N OREGON B B NRN CALIF B B SRN CALIF B B IDAHO B N NEVADA B B W MONTANA B N E MONTANA B A WYOMING B N UTAH B B ARIZONA B B COLORADO B B NEW MEXICO N B N DAKOTA N A S DAKOTA N A NEBRASKA N A KANSAS N A OKLAHOMA A N N TEXAS A N S TEXAS A B W TEXAS N N MINNESOTA N A IOWA N A MISSOURI A A ARKANSAS A N LOUISIANA A B WISCONSIN A A ILLINOIS A A MISSISSIPPI A B MICHIGAN A A INDIANA A A OHIO A N KENTUCKY A N TENNESSEE A B ALABAMA A B 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 B W VIRGINIA A B MARYLAND A B DELAWARE A B VIRGINIA A B N CAROLINA A B S CAROLINA A B GEORGIA A B FL PNHDL N B FL PENIN N B AK N SLOPE B B AK ALEUTIAN N A AK WESTERN B A AK INT BSN B A AK S INT B A AK SO COAST B A AK PNHDL B A 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. $$