PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT FRI APR 25 2008 6-10 DAY OUTLOOK VALID FOR MAY 01 - 05 2008 TODAYS AVAILABLE ENSEMBLE MEAN SOLUTIONS ARE IN ONLY FAIR AGREEMENT ON THE EXPECTED 500-HPA FLOW PATTERN OVER NORTH AMERICA FOR THE 6-10 DAY PERIOD. TROUGHS ARE PROGGED OVER WEST/CENTRAL ALASKA, AND OVER THE INTERMOUNTAIN WEST/ ROCKIES. RIDGES ARE FORECAST OVER THE EAST/CENTRAL CONUS, AND EASTERN ALASKA/WESTERN CANADA. THE ENSEMBLE MEAN SOLUTIONS SHOW POOR AGREEMENT NEAR THE GREAT LAKES AS THE 0Z GFS ENSEMBLE MEAN DEPICTS AN AMPLIFIED RIDGE, THE 12Z ECMWF ENSEMBLE MEAN DEPICTS A NEGATIVELY TILTED TROUGH, AND THE CANADIAN ENSEMBLE MEAN SHOWS AN AMPLIFIED RIDGE WEST OF THE AREA AND A NEGATIVELY TILTED TROUGH EAST OF THE AREA. IN GENERAL THE CONUS IS DOMINATED BY FAST ZONAL FLOW ALTHOUGH THE 0Z GFS ENSEMBLE MEAN IS MORE AMPLIFIED WITH THE CIRCULATION PATTERN COMPARED TO THE OTHER ENSEMBLE MEAN SOLUTIONS. THE OPERATIONAL 0Z AND 6Z GFS DEPICT A SPLIT-FLOW TYPE PATTERN WITH A FAST ZONAL FLOW ACROSS THE SOUTHERN CONUS AND AMPLIFIED CIRCULATION FEATURES OVER THE NORTHERN CONUS/CANADA. A BLOCKING FLOW PATTERN IS PROGGED NEAR SOUTHERN HUDSON BAY. YESTERDAYS 12Z ECMWF IS SIMILAR TO THE OPERATIONAL GFS SOLUTIONS EXCEPT IT DEPICTS A MORE CYCLONIC FLOW PATTERN OVER THE CENTRAL CONUS. THE ENSEMBLE MEAN FORECASTS SHOW FAIR CONTINUITY WITH RESPECT TO THEIR SOLUTIONS FROM YESTERDAY. THE ECMWF ENSEMBLE MEAN WAS GIVEN HEAVY WEIGHT IN TODAYS BLEND CHART SINCE IT HAS BEEN SIGNIFICANTLY OUTPERFORMING THE OTHER MODELS RECENTLY. THE PNA INDEX WHICH RECENTLY HAS BEEN WEAKLY NEGATIVE IS FORECAST TO TREND TOWARDS ZERO BY DAY 7, REMAIN CLOSE TO ZERO THROUGH DAY 10 AND BECOME POSITIVE BY DAY 14. THE NAO INDEX WHICH RECENTLY HAS BEEN NEGATIVE IS FORECAST TO REMAIN NEGATIVE THROUGH DAY 7, TREND TOWARDS ZERO BY DAY 10 AND REMAIN NEAR ZERO THROUGH DAY 14. TODAYS BLEND CHART INDICATES NEAR TO ABOVE NORMAL HEIGHTS OVER ALASKA AND NORTHERN MAINE, AND NEAR TO BELOW NORMAL HEIGHTS ACROSS THE REST OF THE CONUS. THE WEAK RIDGE OVER THE CENTRAL CONUS SHOULD LEAD TO WARMER THAN NORMAL WEATHER FOR MUCH OF THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY AND LEAD TO BELOW MEDIAN PRECIPITATION OVER THE OHIO AND TENNESSEE VALLEYS, AND PARTS OF THE SOUTHEAST. SOUTHERLY FLOW AHEAD OF THE TROUGH OVER WEST/CENTRAL ALASKA SHOULD LEAD TO WARMER THAN NORMAL CONDITIONS OVER EASTERN ALASKA AND THE ALASKAN PANHANDLE. ANOMALOUS NORTHERLY FLOW ON THE REARSIDE OF THE ALASKAN TROUGH LEADS TO BELOW NORMAL TEMPERATURES OVER WESTERN ALASKA AND THE ALEUTIANS. THE TROUGH OVER THE ROCKIES SUGGESTS ABOVE MEDIAN PRECIPITATION IS LIKELY FOR MUCH OF THE PLAINS. COOLER THAN NORMAL WEATHER IS LIKELY OVER THE PACIFIC NORTHWEST, THE NORTHERN INTERMOUNTAIN WEST, THE NORTHERN ROCKIES AND THE NORTHERN PLAINS DUE TO BELOW NORMAL 500-HPA HEIGHTS. TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 10 PERCENT OF TODAY'S OPERATIONAL 0Z GFS CENTERED ON DAY 8...10 PERCENT OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8...10 PERCENT OF TODAY'S OPERATIONAL ECMWF CENTERED ON DAY 7...10 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...10 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...15 PERCENT OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8...AND 35 PERCENT OF TODAY'S EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7. MODEL(S) OF THE DAY: 12Z ECMWF ENSEMBLE FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD IS BELOW AVERAGE... 2 ON A SCALE OF 1 TO 5 DUE TO ONLY FAIR AGREEMENT AMONG THE MODELS AND FORECAST TOOLS. THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE KLEIN, NEURAL NET AND ANALOG SPECIFICATIONS FROM THE BLENDED HEIGHT FIELD, THE KLEIN PROBABILITIES FROM THE ECMWF AND CANADIAN ENSEMBLES, THE CDC TEMPERATURE FORECAST, THE CPC AUTO FORECAST, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE FORECAST, TELECONNECTIONS ON A POSITIVE HEIGHT ANOMALY CENTER AT 59N 70W, AND TELECONNECTIONS ON A NEGATIVE HEIGHT ANOMALY CENTER AT 42N 108W. THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE NEURAL NET AND ANALOG SPECIFICATIONS FROM THE OFFICIAL BLEND, DAILY PRECIPITATION FORECASTS FROM THE VARIOUS MODELS, THE CDC PRECIPITATION FORECAST, THE CPC AUTO FORECAST, NEURAL NET PROBABILITIES FROM THE ECMWF AND CANADIAN ENSEMBLES, TELECONNECTIONS ON A POSITIVE HEIGHT ANOMALY CENTER AT 59N 70W, AND TELECONNECTIONS ON A NEGATIVE HEIGHT ANOMALY CENTER AT 42N 108W. 8-14 DAY OUTLOOK FOR MAY 03 - 09 2008: FOR WEEK 2 THE GFS SUPERENSEMBLE AND CANADIAN ENSEMBLE MEANS INDICATE A SLIGHT DEAMPLIFICATION OF THE 500-HPA CIRCULATION PATTERN FROM THAT DEPICTED DURING THE 6-10 DAY PERIOD. THE 0Z AND 6Z GFS ENSEMBLE MEANS ARE SIMILAR TO THE GFS SUPERENSEMBLE MEAN ALTHOUGH THE 6Z ENSEMBLE MEAN IS A LITTLE MORE AMPLIFIED WITH THE EXPECTED CIRCULATION PATTERN. THE 0Z AND 6Z OPERATIONAL GFS ARE GENERALLY NOT IN GOOD AGREEMENT WITH EACH OTHER OR WITH THE ENSEMBLE MEAN SOLUTIONS. THE EXCEPTION IS OVER THE WESTERN CONUS WHERE THE SOLUTIONS AGREE THAT A TROUGH WILL BE LOCATED, ALTHOUGH THE OPERATIONAL 0Z GFS IS SIGNIFICANTLY MORE AMPLIFIED WITH THIS FEATURE. THE BLEND CHART SHOWS NEAR TO BELOW NORMAL HEIGHTS ALONG THE EAST AND GULF COASTS, THE SOUTHWEST AND CALIFORNIA. NEAR TO ABOVE NORMAL HEIGHTS ARE PROGGED ACROSS THE REMAINDER OF THE CONUS AND ALASKA. THE TEMPERATURE AND PRECIPITATION ANOMALY PATTERN OVER THE CONUS DURING WEEK 2 ARE LITTLE CHANGED FROM THOSE FORECAST DURING THE 6-10 DAY PERIOD. THE AREA OF ABOVE NORMAL TEMPERATURES FORECAST OVER THE SOUTHERN PLAINS FOR 6-10 DAYS IS DISPLACED A BIT TO THE NORTH/NORTHEAST INTO THE MISSISSIPPI VALLEY AND GREAT LAKES DURING WEEK 2. AS THE TROUGH NEAR THE GREAT LAKES LIFTS OUT TO THE NORTHEAST, A DRIER WEATHER PATTERN IS PROGGED OVER NEW ENGLAND DURING WEEK 2 COMPARED TO THE 6-10 DAY PERIOD. THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 10 PERCENT OF TODAY'S OPERATIONAL 0Z GFS CENTERED ON DAY 11...10 PERCENT OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11...15 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...15 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...15 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...AND 35 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 A GENERALLY ZONAL FLOW PATTERN EXPECTED OVER THE CONUS WHICH USUALLY RESULTS IN LOW SKILL SCORES FOR THE FORECASTS, AND RELATIVELY POOR AGREEMENT AMONG THE FORECAST TOOLS. THE 8-14 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTOBLEND FORECAST, KLEIN, ANALOG AND NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND, THE CDC TEMPERATURE FORECAST, AND KLEIN PROBABILITIES FROM THE CANADIAN AND GFS ENSEMBLES. THE 8-14 DAY PRECIPITATION PROG IS BASED ON THE ANALOG AND NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND, THE CPC AUTO FORECAST, THE CDC PRECIPITATION FORECAST, AND NEURAL NET PROBABLITIES FROM THE GFS ENSEMBLE. FORECASTER: R. SCHECHTER 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 16. 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: 19810505 - 19530410 - 19900428 - 19590504 - 19540424 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: 19530410 - 19810505 - 19900428 - 19540424 - 19580425 6 to 10 day Outlook Table OUTLOOK FOR MAY 01 - 05, 2008 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON B N OREGON B B NRN CALIF B B SRN CALIF N B IDAHO B N NEVADA N B W MONTANA B A E MONTANA B A WYOMING B N UTAH N B ARIZONA N B COLORADO B N NEW MEXICO N N N DAKOTA B A S DAKOTA B A NEBRASKA B N KANSAS N N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A N MINNESOTA B A IOWA N N MISSOURI A N ARKANSAS A A LOUISIANA A A WISCONSIN N N ILLINOIS N B MISSISSIPPI A N MICHIGAN N N INDIANA N B OHIO N B KENTUCKY N B TENNESSEE A B ALABAMA A B NEW YORK N A VERMONT B A NEW HAMP B A MAINE N A MASS B A CONN B A RHODE IS B A PENN B N NEW JERSEY B N W VIRGINIA B B MARYLAND B N DELAWARE B N VIRGINIA B N N CAROLINA B B S CAROLINA B B GEORGIA N B FL PNHDL N B FL PENIN N N AK N SLOPE N A AK ALEUTIAN B B AK WESTERN B N AK INT BSN N N AK S INT N B AK SO COAST N B AK PNHDL A B 8 to 14 day Outlook Table OUTLOOK FOR MAY 03 - 09, 2008 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N N OREGON B N 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 N ARIZONA B N COLORADO N A NEW MEXICO N A N DAKOTA N A S DAKOTA N N NEBRASKA N N KANSAS A A OKLAHOMA A A N TEXAS N A S TEXAS N A W TEXAS N A MINNESOTA A A IOWA A N MISSOURI A N ARKANSAS A A LOUISIANA N A WISCONSIN A N ILLINOIS A N MISSISSIPPI N N MICHIGAN A B INDIANA A N OHIO A B KENTUCKY A N TENNESSEE N N ALABAMA N B NEW YORK N B VERMONT N B NEW HAMP B B MAINE N B MASS B B CONN B B RHODE IS B B PENN N B NEW JERSEY B B W VIRGINIA N B MARYLAND B B DELAWARE B B VIRGINIA N B N CAROLINA B B S CAROLINA B B GEORGIA B B FL PNHDL B B FL PENIN B B AK N SLOPE N N AK ALEUTIAN B N AK WESTERN B A AK INT BSN A N AK S INT N A AK SO COAST N A AK PNHDL A 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. $$