PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EDT THU AUG 12 2004 6 TO 10 DAY OUTLOOK FOR AUGUST 18 - 22 2004 . . . . . . . TODAYS 500-HPA GEOPOTENTIAL HEIGHT FORECASTS ARE IN GOOD AGREEMENT OVER THE NORTH AMERICAN VICINITY AND ADJACENT OCEANIC AREAS FOR THE 6-10 DAY PERIOD...WITH THE EXCEPTION OF THE OPERATIONAL ECMWF WHICH IS QUITE UNLIKE THE OTHER SOLUTIONS AND WILL BE BRIEFLY DISCUSSED LATER. THE PRIMARY CIRCULATION FEATURES EXPECTED FOR THIS 6-10 DAY PERIOD INCLUDE A RIDGE EXTENDING FROM THE GREAT BASIN AND ROCKIES NORTHWESTWARD THROUGH INTERIOR BRITISH COLUMBIA AND ACROSS MOST OF ALASKA...AND A MEAN TROUGH OVER THE EASTERN LOWER 48 STATES WHICH IS PART OF A FULL LATITUDE TROUGH STRETCHING FROM NEAR THE NORTH POLE ACROSS ALL OF EASTERN NORTH AMERICA. THERE ARE DIFFERENCES BETWEEN MODEL RUNS AS TO THE PLACEMENT OF THIS MEAN TROUGH...WITH SOME FORE- CASTING THE AXIS NEAR THE EAST COAST AND OTHERS AS FAR WEST AS THE MISSISSIPPI RIVER. THE CONSENSUS POSITION HOWEVER CONTINUES TO BE OVER THE OHIO VALLEY AND APPALACHIANS. AS NOTED ABOVE...TODAYS ECMWF SOLUTION IS VERY DIFFERENT FROM ITS GFS-RELATED COUNTERPARTS. PROB- LEMS ARISE EARLY ON...WITH HURRICANE CHARLEYS POSITION BEING INITIAL- IZED SOMEWHAT SOUTH OF ITS CURRENT LOCATION...AND ULTIMATELY TAKING THE STORM NORTHWESTWARD TO THE TEXAS COAST. THE ECMWF ALSO HAS FAST ZONAL FLOW ACROSS THE NORTHWESTERN U.S. AND SOUTHWESTERN CANADA... SEVERING THE WESTERN RIDGE IN HALF. THE UNLIKELINESS OF THE ECMWF SCENARIO HAS RESULTED IN IT BEING DISCOUNTED TODAY. 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.. THIS IS CONSISTENT WITH THE COOLER TEMPERATURES EXPERIENCED 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 FREQUENTLY...DESPITE BEING PUNCTUATED TEMPORARILY BY SHORT-LIVED PATTERN CHANGES. HURRICANE CHARLEY IS PRESENTLY LOCATED OVER THE NORTHWESTERN CARIB- BEAN SEA. FORECAST PROJECTIONS FROM THE NATIONAL HURRICANE CENTER (NHC) TAKE CHARLEY ACROSS WESTERN CUBA AND NEAR THE OUTERMOST FLOR- IDA KEYS IN 18 TO 24 HOURS. ALTHOUGH THE STATE MOST LIKELY TO EXPER- IENCE LANDFALL IS FLORIDA...THE CENTRAL GULF COAST STATES SHOULD NOT LET DOWN THEIR GUARD IN CASE CHARLEY ASSUMES A MORE WESTERN TRAJEC- TORY. PEOPLE ARE URGED 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 25 PERCENT OF TODAYS GFS ENSEMBLE MEAN CENTERED ON DAY 8...25 PERCENT OF THE CANADIAN ENSEM- BLE MEAN CENTERED ON DAY 8...25 PERCENT OF TODAYS ECMWF ENSEMBLE CENTERED ON DAY 7...15 PERCENT OF TODAYS DAVA SOLUTION CENTERED ON DAY 8...AND 10 PERCENT OF TODAYS OPERATIONAL 0Z GFS CENTERED ON DAY 8. MODEL OF THE DAY: NO PREFERENCE FORECAST CONFIDENCE FOR THE 6 TO 10 DAY PERIOD IS RATED AS ABOVE AVERAGE TODAY...4 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 ...AS WELL AS ON THE LATEST 5-DAY MEAN OBSERVED TEMPERATURES. THE CDC REFORECAST TEMPERATURE TOOL WAS NOT AVAILABLE TODAY. THE HEAVY RAINS PREDICTED FROM TROPICAL STORM BONNIE AND HURRICANE CHARLEY IN THE NEXT FEW DAYS ACROSS MUCH OF THE EASTERN SEABOARD WILL LIKELY HOLD TEMPERATURES DOWN A BIT OVER THAT REGION DURING THE 6-10 DAY RANGE. THE 6 TO 10 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...AND BIAS CORREC- TED PRECIPITATION FROM THE 0Z GFS. THE CDC REFORECAST TOOL FOR PRE- CIPITATION WAS NOT AVAILABLE TODAY. . . . . . . . 8 TO 14 DAY OUTLOOK FOR AUGUST 20 - 26 2004 FOR WEEK 2...LITTLE CHANGE IS ANTICIPATED IN THE MEAN FLOW PATTERN FROM DAYS 6-10. WEAK TROUGHING REMAINS OFF THE U.S. WEST COAST... AND A SIGNIFICANTLY STRONGER TROUGH PERSISTS OVER THE EAST-CENTRAL STATES. ANOMALOUS RIDGING IS INDICATED OVER MOST OF ALASKA...AND ALSO OVER THE SOUTHERN CANADIAN MARITIMES REGION. 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 6Z GFS CENTERED ON DAY 11 ...AND 10 PERCENT OF YESTERDAYS 12Z GFS CENTERED ON DAY 10. FORECAST CONFIDENCE FOR THE 8 TO 14 DAY PERIOD IS ABOVE AVERAGE...4 ON A SCALE OF 1 TO 5. THE 8 TO 14 DAY TEMPERATURE PROG IS BASED ON THE KLEIN...NEURAL NET- WORK...AND ANALOG SPECIFICATIONS FROM THE OFFICIAL 500-HPA BLEND. A NEW TOOL...THE WEEK 2 GFS ENSEMBLE MEAN 2-METER CALIBRATED TEMPERA- TURE TOOL...WAS ALSO USED TO SOME EXTENT IN THE FORMULATION OF THE SURFACE TEMPERATURE PROG. 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...AND BIAS CORREC- TED PRECIPITATION FROM THE 0Z GFS. 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: 19650730 - 19960723 - 19620726 - 19930801 - 19500810 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: 19650729 - 19960723 - 19620726 - 19630814 - 19500723 6 to 10 day Outlook Table OUTLOOK FOR AUG 18 - 22, 2004 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON A B NRN CALIF A B SRN CALIF A B IDAHO A B NEVADA A B W MONTANA N B E MONTANA N B WYOMING B A UTAH N N ARIZONA N N COLORADO B A NEW MEXICO B A N DAKOTA B N S DAKOTA B N NEBRASKA B A KANSAS B A OKLAHOMA B A N TEXAS B N S TEXAS B N W TEXAS B A MINNESOTA B A IOWA B A MISSOURI B A ARKANSAS B A LOUISIANA B N WISCONSIN B A ILLINOIS B A MISSISSIPPI B N MICHIGAN B N INDIANA B A OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA B N NEW YORK B N VERMONT N N NEW HAMP N N MAINE N N MASS N A CONN N A RHODE IS N A PENN B A NEW JERSEY B A W VIRGINIA B A MARYLAND B A DELAWARE B A VIRGINIA B A N CAROLINA B N S CAROLINA B N GEORGIA B N FL PNHDL B N 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 B AK SO COAST A B AK PNHDL A B 8 to 14 day Outlook Table OUTLOOK FOR AUG 20 - 26, 2004 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON A B NRN CALIF A B SRN CALIF A N IDAHO A B NEVADA A B W MONTANA A N E MONTANA B A WYOMING A A UTAH N N ARIZONA N A COLORADO B A NEW MEXICO N A N DAKOTA B N S DAKOTA B N NEBRASKA B A KANSAS B A OKLAHOMA B A N TEXAS B N S TEXAS B N W TEXAS B A MINNESOTA B B IOWA B A MISSOURI B A ARKANSAS B A LOUISIANA B B WISCONSIN B B ILLINOIS B A MISSISSIPPI B A MICHIGAN B B INDIANA B A OHIO B A KENTUCKY B A TENNESSEE B A ALABAMA B N NEW YORK B N VERMONT N N NEW HAMP N N MAINE A N MASS N N CONN N N RHODE IS N N PENN B N NEW JERSEY B N W VIRGINIA B A MARYLAND B A DELAWARE B N VIRGINIA B A N CAROLINA B A S CAROLINA B N GEORGIA B N FL PNHDL B N FL PENIN N N AK N SLOPE A B AK ALEUTIAN A A AK WESTERN A B AK INT BSN A B AK S INT A B AK SO COAST A B AK PNHDL A 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. $$