PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS CLIMATE PREDICTION CENTER NCEP NATIONAL WEATHER SERVICE WASHINGTON DC 3 PM EST TUE JAN 1 2002 6 TO 10 DAY OUTLOOK FOR JAN 7 - 11 2002 . . . . . . . . MODEL COMPARISONS: THE PRINCIPAL ASSORTMENT OF MODEL SOLUTIONS TODAY CONTINUE TO BE IN GOOD AGREE- MENT ON AN AMPLIFIED MEAN RIDGE ALONG THE WEST COAST OF NORTH AMERICA...A TROUGH CENTERED OVER THE EASTERN U.S...AND ANOTHER MEAN TROUGH FROM FAR EASTERN SIBERIA ACROSS THE BERING SEA TO WESTERN ALASKA. THIS POSITIVELY PHASED PNA (PACIFIC NORTH AMERICAN) PATTERN IS SUPPORTED BY THE HIGH RESOLUTION MRF - THE ENSEMBLE AVERAGE - THE DAVA (DIVERGENT ANOMALY VORTICITY ADVECTION) MODEL - AND THE ECMWF SOLUTION...WITH THE DAVA PREDICTING A MORE POSITIVELY SLOPED TROUGH FROM THE EASTERN GREAT LAKES REGION SOUTHWESTWARD INTO THE SOUTHERN PLAINS. THIS PATTERN SUGGESTS RELATIVELY MILD CONDITIONS WILL PREVAIL ACROSS THE NORTHWESTERN TWO- THIRDS OF THE LOWER 48...WITH NEAR TO BELOW AVERAGE TEMPERATURES OVER THE SOUTHEASTERN THIRD OF THE NATION. WITH THE EASTERN TROUGH AXIS EXPECTED TO RUN THROUGH THE EAST-CENTRAL STATES...WE WOULD EXPECT TO SEE A SERIES OF STORMS FORMING NEAR THE GULF COAST AND TRACKING NORTHEASTWARD NEAR THE ATLANTIC COAST. THIS COULD SET THE STAGE FOR SNOWY/ICY CONDITIONS ACROSS THE MIDDLE AND NORTH- ERN ATLANTIC COASTAL STATES...THOUGH MUCH DEPENDS UPON ACTUAL PHASING OF NORTH- ERN STREAM AND SOUTHERN STREAM SHORTWAVES AND THE EXACT TRACK THAT EACH AREA OF LOW PRESSURE TAKES. . . . . . . . . CONFIDENCE IN TODAYS FORECAST IS RATED AS ABOVE AVERAGE... 4 ON A 1-5 SCALE... LARGELY DUE TO GOOD NUMERICAL MODEL AGREEMENT. THE OFFICIAL 500 MB HEIGHT FORECAST FOR THE 6 TO 10 DAY PERIOD USES 30 PERCENT OF TODAYS MRF ENSEMBLE MEAN CENTERED ON DAY 8... 30 PERCENT OF TODAYS DAVA SOL- UTION CENTERED ON DAY 8... 15 PERCENT OF TODAYS HIGH RESOLUTION MRF CENTERED ON DAY 8... 15 PERCENT OF TODAYS ECMWF MODEL CENTERED ON DAY 7... AND 10 PER- CENT OF THE MOST RECENT 5-DAY MEAN OBSERVED PATTERN. . . . . . . . . MODEL OF THE DAY: MRF ENSEMBLE AND DAVA THE TEMPERATURE PROG IS BASED PRIMARILY ON A CONSENSUS BETWEEN THE KLEIN OBJEC- TIVE SPECIFICATIONS FROM THE BLEND...AND THE SURFACE ANALOGS FROM THE DAVA - THE MRF - AND ECMWF MODELS. THE ANOMALOUS WARMTH EXPECTED OVER THE NORTHERN ATLANTIC STATES IS ATTRIBUTED TO EASTERLY ANOMALOUS FLOW OF MODIFIED ATLANTIC AIR. THE LACK OF BITTER COLD DRY AIR...ALONG WITH THE INCREASED MOISTURE CON- TENT FROM THE ATLANTIC...SHOULD PRIMARILY CONTRIBUTE TO ELEVATED OVERNIGHT MINIMUM TEMPERATURES FOR NEW ENGLAND AND MOST OF NEW YORK. THE PRECIPITATION PROG IS BASED MOSTLY ON THE ACCUMULATED MRF MODEL PRECIPITA- TION CORRECTED FOR RECENT BIASES...AND IS CONSISTENT WITH THE PREDICTED STORM TRACKS SHOWN BY THE MRF. . . . . . . . . 8 TO 14 DAY OUTLOOK FOR JAN 9 - 15 2002 . . . . . . . . TODAYS WEEK 2 MRF AND ENSEMBLE MEAN ARE ALSO IN GOOD GENERAL AGREEMENT...THOUGH THE MRF SHOWS A SUBTLE SPLIT IN THE NORTH AMERICAN FLOW PATTERN. THE NORTHERN BRANCH OF THE WESTERLIES FLATTENS OUT MORE OVER ALASKA AND NORTHERN CANADA... IMPLYING SOMEWHAT FASTER ZONAL FLOW COMPARED WITH RECENT HIGHLY MERIDIONAL PAT- TERNS. WITH THE BERING SEA TROUGH RETROGRADING BACK OVER SIBERIA...ALASKA SHOULD EXPERIENCE A WELCOME MODERATION IN TEMPERATURES. CONFIDENCE IS THOUGHT TO BE NEAR AVERAGE TODAY...RATED 3 ON A SCALE OF 1-5. THE BLENDED 500 MB HEIGHT PATTERN USES 60 PERCENT OF TODAYS MRF ENSEMBLE MEAN CENTERED ON DAY 11... AND 40 PERCENT OF TODAYS MRF MODEL CENTERED ON DAY 11. THE TEMPERATURE OUTLOOK IS BASED MAINLY ON A CONSENSUS OF THE KLEIN AND NEURAL NET SPECIFICATIONS FROM THE OFFICIAL HEIGHT PROG...AND ALSO FROM THE KLEINS OPERATING OFF THE MRF AND ENSEMBLE MEAN MODELS. THE PRECIPITATION FORECAST IS BASED PRIMARILY ON THE ACCUMULATED MRF MODEL PRECIPITATION OUTPUT CORRECTED FOR RECENT BIASES...AND IS GENERALLY CONSISTENT WITH THE EXPECTED STORM TRACKS. FORECASTER: A. ARTUSA NOTES: A WEB PAGE WITH FORECAST TOOLS ON IT IS AVAILABLE EACH DAY AT 3 PM AT: WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/PREDICTIONS/SHORT_RANGE AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OTHERWISE - FORECASTS INCORPORATE FORECASTER INPUT. MODEL OF THE DAY - FOR 6-10 DAYS - IS THE MODEL WHOSE SOLUTION IS CONSIDERED TO BE MORE RELIABLE THAN USUAL - AND MAY BE GIVEN HIGHER THAN TYPICAL WEIGHT IN THE BLEND. NO MODEL OF THE DAY IS CHOSEN FOR 8-14 DAYS. 500 MB HEIGHT IS THE HEIGHT - IN METERS - ABOVE MEAN SEA LEVEL - AT WHICH ABOUT HALF OF THE MASS OF THE ATMOSPHERE LIES ABOVE AND BELOW - AS MEASURED BY THE PRESSURE. UPPER AIR STORM SYSTEMS TEND TO BE STEERED IN THE DIRECTION OF THE WINDS AT 500 HPA. 500-HPA SYSTEMS CORRELATE STRONGLY WITH SURFACE WEATHER. ANOMALY - THE ARITHMETIC DIFFERENCE BETWEEN THE VALUE OF A VARIABLE AT A GIVEN PLACE AND TIME AND THE LONG-TERM AVERAGE OF THAT VARIABLE AT THAT PLACE AND TIME OF YEAR. . . . . . . . . TELECONNECTIONS GIVE THE HISTORICAL RELATIONSHIP BETWEEN THE 500-HPA HEIGHT AT A GIVEN POINT AND ALL OTHER POINTS ON A MAP FOR A GIVEN TIME OF YEAR. WE AVERAGE THE TOP/BOTTOM 10% OF DAILY MAPS FROM 1950-1999 FOR THE SAME TIME OF YEAR HAVING THE HIGHEST/LOWEST 500-HPA HEIGHT AT THE SPECIFIED POINT. KLEIN AND NEURAL NETWORK SPECIFICATIONS GIVE THE HISTORICAL RELATIONSHIP BETWEEN 500-HPA HEIGHT ANOMALIES AND SURFACE TEMPERATURE AND PRECIPITATION. KLEIN SPECIFICATIONS TEND TO EMPHASIZE REGIONAL TELECONNECTIONS - WHILE THOSE FROM THE NEURAL NETWORK WORK FROM GLOBAL TELECONNECTIONS. DAVA MEANS DIVERGENT ANOMALY VORTICITY ADVECTION MODEL. THIS IS A BAROTROPIC MODEL WITH DIVERGENCE IN IT TO ALLOW MORE ACCURATE PREDICTION OF LONG WAVES THAN A NON-DIVERGENT BAROTROPIC MODEL. REFERENCE: QIN J. AND H.M. VAN DEN DOOL - 1996: SIMPLE EXTENSIONS OF AN NWP MODEL. MON. WEA. REV. - VOL 124 - PP 277-287. 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 ON THURSDAY JANUARY 17. . . . . . . . . 6 to 10 day Outlook Table STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A N OREGON A N NRN CALIF A N SRN CALIF A B IDAHO A B NEVADA A B W MONTANA A N E MONTANA A B WYOMING A B UTAH A B ARIZONA N B COLORADO A B NEW MEXICO N B N DAKOTA A N S DAKOTA A N NEBRASKA A B KANSAS A B OKLAHOMA A B N TEXAS N B S TEXAS B B W TEXAS N B MINNESOTA A N IOWA A N MISSOURI A B ARKANSAS N B LOUISIANA B B WISCONSIN A N ILLINOIS A B MISSISSIPPI N B MICHIGAN A B INDIANA N B OHIO N B KENTUCKY N B TENNESSEE N B ALABAMA B B NEW YORK A N VERMONT A A NEW HAMP A A MAINE A A MASS A A CONN A A RHODE ISL A A PENN N N NEW JERSEY N A W VIRGINIA N N MARYLAND N A DELAWARE N A VIRGINIA N N N CAROLINA N N S CAROLINA B N GEORGIA B N FL PNHDL B A FL PENIN B A AK N SLOPE B B AK ALEUTIAN B A AK WESTERN B A AK INT BSN N B AK S INT A N AK S COAST A A AK PNHDL A N 8 to 14 day Outlook Table STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A B OREGON N B NRN CALIF A B SRN CALIF A B IDAHO N B NEVADA N B W MONTANA N B E MONTANA A B WYOMING N B UTAH N B ARIZONA N B COLORADO N B NEW MEXICO N B N DAKOTA A N S DAKOTA A B NEBRASKA A B KANSAS N B OKLAHOMA N B N TEXAS N B S TEXAS B B W TEXAS N B MINNESOTA A N IOWA N N MISSOURI N B ARKANSAS B B LOUISIANA B B WISCONSIN N N ILLINOIS N B MISSISSIPPI B B MICHIGAN N N INDIANA B B OHIO B B KENTUCKY B B TENNESSEE B B ALABAMA B B NEW YORK B N VERMONT N N NEW HAMP N N MAINE A A MASS N N CONN N N RHODE ISL N N PENN B B NEW JERSEY B N W VIRGINIA B B MARYLAND B N DELAWARE B N VIRGINIA B N N CAROLINA B N S CAROLINA B N GEORGIA B N FL PNHDL B N FL PENIN B A AK N SLOPE A B AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A AK S INT A A AK S COAST A A 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 N - NEAR NORMAL 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 - ON AFOS AS NFDPMDMRD. NNNN NNNN