PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT TUE AUG 10 2004 6 TO 10 DAY OUTLOOK FOR AUGUST 16 - 20 2004 . . . . . . . TODAYS 500-HPA GEOPOTENTIAL HEIGHT FORECASTS CONTINUE TO BE IN FAIR AGREEMENT OVER THE NORTH AMERICAN VICINITY AND ADJACENT OCEANIC AREAS FOR THE 6-10 DAY PERIOD. INTERMODEL COMPARISONS DEMONSTRATE CONSIDERABLE VARIATION IN AMPLITUDE AND PHASE OF PREDICTED LONG WAVES...WHICH TRIMS BACK THE DEGREE OF CONFIDENCE IN THIS FORECAST. THE PRIMARY CIRCULATION FEATURES...(AS SHOWN BY THOSE MODELS USED IN THE FORMULATION OF THE BLEND)... EXPECTED FOR THIS 6-10 DAY PERIOD INCLUDE A RIDGE EXTENDING FROM THE GREAT BASIN AND ROCKY MOUNTAINS NORTHWESTWARD THROUGH INTERIOR BRITISH COLUMBIA AND MUCH OF ALASKA WITH A POSITIVE HEIGHT ANOMALY CENTER OF +120 METERS NEAR BARROW... ANOTHER STRONG ANOMALOUS BLOCK CENTERED OVER SOUTHERN GREENLAND... AND A ZONALLY ORIENTED TROUGH FROM THE SEA OF OKHOTSK ACROSS THE BERING SEA AND GULF OF ALASKA REGION. ANOTHER PRIMARY FEATURE IS A MEAN TROUGH OVER THE EASTERN LOWER 48 STATES...WHICH IS PART OF A FULL LATITUDE TROUGH STRETCHING FROM THE NORTH POLE ACROSS ALL OF EASTERN NORTH AMERICA. INSPECTION OF 0Z GFS MODEL ERRORS OVER THE PAST WEEK (AND TO A LES- SER EXTENT THE PAST MONTH) REVEALS THAT THIS MODEL HAS BEEN UNDER- FORECASTING 500-HPA HEIGHTS OVER ALASKA...WHILE OVER-FORECASTING HEIGHTS OVER THE NORTHEASTERN U.S. AND ALSO OFF THE BRITISH COLUM- BIA COAST. THIS IS CONSISTENT WITH THE COOLER TEMPERATURES EXPER- IENCED LATELY ACROSS THE NORTHEAST...AND THE CONTINUING ANOMALOUS WARMTH OVER ALASKA. THE STABILITY OF THESE BIASES OVER THE PAST MONTH SHOWS THAT THE PRESENT CIRCULATION REGIME IS RECURRING FRE- QUENTLY...DESPITE BEING PUNCTUATED TEMPORARILY BY SHORT-LIVED PAT- TERN CHANGES. TROPICAL STORM CHARLEY IS NOW LOCATED OVER THE EAST-CENTRAL CARIB- BEAN. FORECAST PROJECTIONS FROM THE NATIONAL HURRICANE CENTER TAKE CHARLEY TOWARDS THE YUCATAN CHANNEL AND STRENGTHEN IT TO A HURRI- CANE BY FRIDAY. IT APPEARS AS THOUGH THIS SYSTEM IS HEADED FOR THE EASTERN GULF OF MEXICO AND COULD HAVE A SIGNIFICANT IMPACT ON FLOR- IDA BY EARLY NEXT WEEK. DETAILS ARE FAR FROM CERTAIN AT THIS RANGE ...AND PEOPLE ARE ADVISED TO MONITOR THE PROGRESS OF THIS STORM BY CONSULTING THEIR LOCAL NEWS MEDIA AND THE INTERNET WEBSITE OF THE NATIONAL HURRICANE CENTER LOCATED AT HTTP://WWW.NHC.NOAA.GOV THE OFFICIAL D+8 HEIGHT PROG CONSISTS OF 40 PERCENT OF TODAYS GFS ENSEMBLE MEAN CENTERED ON DAY 8...30 PERCENT OF THE CANADIAN ENSEM- BLE MEAN CENTERED ON DAY 8...20 PERCENT OF TODAYS DAVA SOLUTION CEN- TERED ON DAY 8...AND 10 PERCENT OF TODAYS OPERATIONAL 0Z GFS CENTER- ED ON DAY 8. MODEL OF THE DAY: GFS ENSEMBLE (THE ECMWF ENSEMBLE HAS BEEN SCORING BETTER LATELY BUT COULD NOT BE INCORPORATED INTO TODAYS OFFICIAL HEIGHT FORECAST). FORECAST CONFIDENCE FOR THE 6 TO 10 DAY PERIOD IS RATED AS AVERAGE TODAY...3 ON A SCALE FROM 1 TO 5. THE 6 TO 10 DAY TEMPERATURE PROG IS BASED ON THE KLEIN... NEURAL NETWORK...AND ANALOG SPECIFICATIONS FROM THE OFFICIAL 500-HPA BLEND AND THE CDC REFORECAST TEMPERATURE TOOL. THE 6 TO 10 DAY PRECIPITATION PROG IS BASED ON NEURAL NET AND ANALOG SPECIFICATIONS FROM THE OFFICIAL 500-HPA PROG...CDC REFORECAST PRE- CIPITATION...CALIBRATED PRECIPITATION PERCENTAGES FROM THE GFS ENSEM- BLE MEMBERS...AND BIAS CORRECTED PRECIPITATION FROM THE 0Z GFS. . . . . . . . 8 TO 14 DAY OUTLOOK FOR AUGUST 18 - 24 2004 THOUGH TODAYS GFS ENSEMBLE AND DAVA D+11 RUNS ARE SUGGESTING GOOD CONTINUITY WITH TODAYS OFFICIAL 6-10 DAY HEIGHT PROG...THE OPERA- TIONAL 0Z GFS AND YESTERDAYS 18Z GFS SOLUTIONS ARE PREDICTING AN OVERALL DEAMPLIFICATION OF THE CIRCULATION PATTERN OVER MUCH OF NORTH AMERICA DURING WEEK 2. IF TRUE...AND THE WESTERLIES INCREASE IN STRENGTH NEAR THE 50N LATITUDE CIRCLE...IT WILL MEAN GREATER UN- CERTAINTY REGARDING THE TIMING OF INDIVIDUAL SHORT WAVES EMBEDDED WITHIN THE MEAN FLOW...AND A FAIRLY CHANGEABLE TEMPERATURE REGIME. THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 50 PERCENT OF TODAYS GFS ENSEMBLE MEAN CENTERED ON DAY 11...20 PERCENT OF TODAYS DAVA CENTERED ON DAY 11...20 PERCENT OF TODAYS 0Z GFS CENTERED ON DAY 11...AND 10 PERCENT OF YESTERDAYS 18Z GFS CENTERED ON DAY 10. FORECAST CONFIDENCE FOR THE 8 TO 14 DAY PERIOD IS BELOW AVERAGE...2 ON A SCALE OF 1 TO 5. THE 8 TO 14 DAY TEMPERATURE PROG IS BASED ON THE KLEIN...NEURAL NET- WORK...ANALOG SPECIFICATIONS FROM THE OFFICIAL 500-HPA BLEND AND THE CDC REFORECAST TEMPERATURE TOOL. THE 8 TO 14 DAY PRECIPITATION PROG IS BASED ON NEURAL NET AND ANALOG SPECIFICATIONS FROM THE OFFICIAL 500-HPA PROG...CALIBRATED PRECIPI- TATION PERCENTAGES FROM THE GFS ENSEMBLE MEMBERS...BIAS CORRECTED PRECIPITATION FROM THE 0Z GFS...AND CDC REFORECAST PRECIPITATION. FORECASTER: A. ARTUSA . . . . . . . NOTES: 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. EFFECTIVE THURSDAY MAY 17 2001...THE CLIMATE PREDICTION CENTER HAS SWITCHED TO 1971-2000 BASE PERIOD MEANS FOR TEMPERATURE... PRECIPITATION...AND 500-HPA HEIGHTS AS REFERENCE IN THE CLIMATE OUTLOOKS. THE 1971-2000 BASE PERIOD MEANS HAVE REPLACED THE 1961-1990 BASE PERIOD MEANS. THE NEXT MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED THURSDAY... AUGUST 19. 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: 19650729 - 19630814 - 19500810 - 19620726 - 19960722 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 7 DAY PERIODS CENTERED ON THE FOLLOWING DATES: 19630814 - 19540809 - 19650729 - 19530819 - 19500810 6 to 10 day Outlook Table OUTLOOK FOR AUG 16 - 20, 2004 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON A A NRN CALIF A B SRN CALIF A B IDAHO N B NEVADA A B W MONTANA N B E MONTANA N B WYOMING N B UTAH N B ARIZONA A N COLORADO B A NEW MEXICO N A N DAKOTA B N S DAKOTA B N NEBRASKA B N KANSAS B N OKLAHOMA B N N TEXAS N B S TEXAS N B W TEXAS N A MINNESOTA B A IOWA B N MISSOURI B N ARKANSAS B B LOUISIANA B N WISCONSIN B A ILLINOIS B N MISSISSIPPI B N MICHIGAN B A INDIANA B N OHIO B N KENTUCKY B N TENNESSEE B N ALABAMA B N NEW YORK B N VERMONT B N NEW HAMP B N MAINE B N MASS B N CONN B N RHODE IS B N PENN B N NEW JERSEY B N W VIRGINIA B N MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B A S CAROLINA B A GEORGIA B A FL PNHDL B A FL PENIN N A AK N SLOPE A B AK ALEUTIAN A A AK WESTERN A B AK INT BSN A B AK S INT A N AK SO COAST A A AK PNHDL A N 8 to 14 day Outlook Table OUTLOOK FOR AUG 18 - 24, 2004 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N A OREGON N A NRN CALIF A B SRN CALIF N B IDAHO B A NEVADA N B W MONTANA B A E MONTANA B A WYOMING B N UTAH B B ARIZONA N B COLORADO B A NEW MEXICO N B N DAKOTA B N S DAKOTA B N NEBRASKA B A KANSAS B A OKLAHOMA B N N TEXAS B B S TEXAS N B W TEXAS A B MINNESOTA B N IOWA B A MISSOURI B A ARKANSAS B N LOUISIANA B N WISCONSIN B A ILLINOIS B A MISSISSIPPI B N MICHIGAN B A INDIANA B A OHIO B A KENTUCKY B N TENNESSEE B N ALABAMA B N NEW YORK N N VERMONT N N NEW HAMP N N MAINE N N MASS N N CONN N N RHODE IS N N PENN N N NEW JERSEY N N W VIRGINIA N N MARYLAND N N DELAWARE N N VIRGINIA N N N CAROLINA N N S CAROLINA B N GEORGIA B N FL PNHDL B N FL PENIN B N AK N SLOPE A B AK ALEUTIAN A A AK WESTERN A A AK INT BSN A N AK S INT A A AK SO COAST A 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. $$