PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD 300 PM EST THU DEC 13 2007 6-10 DAY OUTLOOK VALID FOR DEC 19 - 23 2007 FOR THE 6-10 DAY PERIOD... TODAYS ENSEMBLE MEAN SOLUTIONS ARE IN REASONABLY GOOD AGREEMENT IN DEPICTING A DEEP TROUGH FROM ALASKA INTO THE WESTERN CONUS... NEARLY ZONAL FLOW ACROSS THE CENTRAL AND EASTERN CONUS... AND A WEAK TROUGH NEAR THE EAST COAST. THE GREATEST UNCERTAINTY IN THE EXPECTED 500-HPA FLOW PATTERN IS HOW PROGRESSIVE THE PATTERN BECOMES. THE GFS-BASED ENSEMBLE MEAN SOLUTIONS AND THE OPERATIONAL 0Z AND 6Z GFS MODEL RUNS ARE MORE PROGRESSIVE COMPARED TO THE 12Z ECMWF ENSEMBLE MEAN AND THE OPERATIONAL 0Z ECMWF MODEL RUN. IN ADDITION... THE ECMWF ENSEMBLE MEAN SOLUTION INDICATES A TROUGH CLOSER TO THE EAST COAST THAN THE GFS-BASED ENSEMBLE MEAN SOLUTIONS. THE CANADIAN ENSEMBLE MEAN WAS DISCOUNTED AS AN OUTLIER. THE MOST DOMINANT 500-HPA HEIGHT ANOMALY CENTER REMAINS THE LARGE NEGATIVE ANOMALY CENTER (GREATER THAN 200 METERS) OVER SOUTHERN ALASKA. TELECONNECTIONS ON THIS PERSISTENT ANOMALY CENTER AND CONTINUITY FAVORS THE 12Z ECMWF ENSEMBLE MEAN AND IT WILL BE WEIGHTED MOST HEAVILY IN THE OFFICIAL BLEND. FOLLOWING A FRIGID START TO THE WEEK... A MODERATING TREND SHOULD OCCUR ACROSS THE NORTHEAST AND NEW ENGLAND. HOWEVER... THE EXPECTED FRESH SNOW COVER MAY TEMPER THE WARMING TREND. ABOVE NORMAL TEMPERATURES ARE FORECAST FOR THE MID-ATLANTIC... BUT THE TROUGH NEAR THE EAST COAST MAY RESULT IN NEAR NORMAL TEMPERATURES FOR THE SOUTH ATLANTIC COASTAL AREAS AND THE FLORIDA PENINSULA. ABOVE NORMAL 500-HPA HEIGHTS FAVOR ABOVE NORMAL TEMPERATURES ACROSS THE PLAINS... MISSISSIPPI VALLEY... AND MIDWEST. NEAR TO BELOW NORMAL TEMPERATURES ARE FORECAST FOR CALIFORNIA AND THE SOUTHWEST. TEMPERATURE TOOLS ARE IN EXCELLENT AGREEMENT THAT ALASKA WILL EXPERIENCE WELL BELOW NORMAL TEMPERATURES. DURING THE PAST SEVERAL DAYS... LITTLE CHANGE HAS OCCURRED TO THE PRECIPITATION OUTLOOK. ABOVE NORMAL PRECIPIATION REMAINS LIKELY FOR THE WEST COAST WHILE BELOW NORMAL PRECIPITATION REMAINS LIKELY FOR THE NORTHERN PLAINS. A PERSISTENT STORM TRACK FOCUSED FROM THE SOUTHERN PLAINS INTO THE OHIO VALLEY SHOULD RESULT IN ABOVE NORMAL PRECIPITATION FOR THOSE AREAS. NEAR TO ABOVE NORMAL PRECIPITATION IS FORECAST FOR THE DROUGHT PARCHED AREAS OF THE SOUTHERN APPALACHIANS BUT BELOW NORMAL PRECIPITATION IS EXPECTED ACROSS FLORIDA. AN INCREASE IN MOIST WESTERLY FLOW MAY BRING ABOVE NORMAL PRECIPITATION TO THE ALEUTIANS. ELSEWHERE... ACROSS ALASKA... BITTERLY COLD TEMPERATURES WILL BE ACCOMPANIED BY BELOW NORMAL PRECIPITATION. 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...20 PERCENT OF TODAY'S OPERATIONAL ECMWF CENTERED ON DAY 7...20 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...AND 40 PERCENT OF TODAY'S EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7. MODEL(S) OF THE DAY: ECMWF ENSEMBLE MEAN FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD IS ABOVE AVERAGE... 4 ON A SCALE OF 1 TO 5 DUE TO REASONABLY GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS. THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTO FORECAST... ANALOGS OF THE OFFICIAL BLEND AND VARIOUS MODELS... NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND... THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE GUIDANCE... THE CDC TEMPERATURE TOOL... AND TELECONNECTIONS ON A NEGATIVE 500-HPA HEIGHT ANOMALY CENTERED AT 60N 150W. THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE CPC AUTO FORECAST... ANALOGS OF THE OFFICIAL BLEND AND VARIOUS MODELS... NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND... DAILY PRECIPITATION FORECASTS FROM THE VARIOUS MODELS... AND TELECONNECTIONS ON A NEGATIVE 500-HPA HEIGHT ANOMALY CENTERED AT 60N 150W. 8-14 DAY OUTLOOK FOR DEC 21 - 27 2007: THE GFS-BASED ENSEMBLE MEAN SOLUTIONS ALONG WITH THE OPERATIONAL 0Z AND 6Z GFS MODEL RUNS INDICATE THAT THE 500-HPA FLOW PATTERN WILL REMAIN SLOWLY PROGRESSIVE AS A TROUGH MOVES INTO THE ROCKIES. THE OFFICIAL BLEND SHOWS ABOVE NORMAL 500-HPA HEIGHTS ACROSS THE GREAT LAKES AND NORTHEAST WITH NEAR TO SLIGHLY BELOW NORMAL 500-HPA HEIGHTS ACROSS THE REMAINDER OF THE CONUS. WELL BELOW NORMAL 500-HPA HEIGHTS PERSIST ACROSS ALASKA. AS THE 500-HPA MEAN TROUGH SHIFTS EAST... ABOVE NORMAL TEMPERATURES SHOULD SPREAD INTO THE EAST AND BELOW NORMAL TEMPERATURES SHOULD EXPAND INTO THE ROCKIES. MEANWHILE... ABOVE NORMAL TEMPERATURES WILL PERSIST ACROSS THE MISSISSIPPI VALLEY AND MIDWEST. WELL BELOW NORMAL 500-HPA HEIGHTS WILL LIKELY CONTINUE THE BELOW NORMAL TEMPERATURES ACROSS ALASKA. THE PROGGED 500-HPA HEIGHT FIELD AND PRECIPITATION TOOLS SUGGEST THAT A GRADUAL DRYING TREND MAY BEGIN FOR SOUTHERN CALIFORNIA AND THE DESERT SOUTHWEST BUT THE PACIFIC NORTHWEST WILL LIKELY REMAIN WETTER THAN NORMAL. THE PERSISTENT STORM TRACK WILL MAINTAIN ABOVE NORMAL PRECIPITATION FROM THE SOUTHERN PLAINS INTO THE OHIO VALLEY AND MID-ATLANTIC. DURING THE PAST FEW DAYS... MODEL GUIDANCE HAS TRENDED WETTER FOR THE EXCEPTIONAL DROUGHT AREAS OF THE SOUTHEAST DUE TO LOWER 500-HPA HEIGHTS. THE FLORIDA PENINSULA SHOULD REMAIN DRIER THAN NORMAL. ABOVE NORMAL PRECIPITATION IS FORECAST FOR THE ALEUTIANS AND THE ALASKAN PANHANDLE WITH BELOW NORMAL PRECIPITATION FOR THE REMAINDER OF ALASKA. 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...20 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...AND 40 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11. FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS ABOVE AVERAGE... 4 ON A SCALE OF 1 TO 5 DUE TO GOOD AGREEMENT AMONG THE GFS MODEL SOLUTIONS. THE 8-14 DAY TEMPERATURE PROG IS BASED ON THE CPC AUTO FORECAST... ANALOGS OF THE OFFICIAL BLEND AND VARIOUS MODELS... NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND... THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE GUIDANCE... AND THE CDC TEMPERATURE TOOL. THE 8-14 DAY PRECIPITATION PROG IS BASED ON THE CPC AUTO FORECAST... ANALOGS OF THE OFFICIAL BLEND AND VARIOUS MODELS... NEURAL NET SPECIFICATIONS FROM THE OFFICIAL BLEND... AND THE CPC CALIBRATED PRECIPITATION FROM THE GFS-BASED MODELS. FORECASTER: PUGH 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 DECEMBER 20. 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: 19911201 - 19711227 - 19981221 - 19881227 - 19901222 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: 19911201 - 19781122 - 19981221 - 19901223 - 19611213 6 to 10 day Outlook Table OUTLOOK FOR DEC 19 - 23, 2007 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON N A OREGON N A NRN CALIF N A SRN CALIF B A IDAHO A A NEVADA N A W MONTANA A N E MONTANA A B WYOMING A B UTAH N A ARIZONA B A COLORADO A N NEW MEXICO N A N DAKOTA A B S DAKOTA A B NEBRASKA A B KANSAS A N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS A A MINNESOTA A B IOWA A N MISSOURI A A ARKANSAS A A LOUISIANA A A WISCONSIN A B ILLINOIS A A MISSISSIPPI A A MICHIGAN A N INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A A ALABAMA A N NEW YORK A A VERMONT N A NEW HAMP N A MAINE N A MASS N A CONN A A RHODE IS N A PENN A A NEW JERSEY A A W VIRGINIA A A MARYLAND A A DELAWARE A A VIRGINIA A A N CAROLINA A A S CAROLINA A N GEORGIA A B FL PNHDL A B FL PENIN N B AK N SLOPE B B AK ALEUTIAN B A AK WESTERN B B AK INT BSN B B AK S INT B B AK SO COAST B B AK PNHDL B N 8 to 14 day Outlook Table OUTLOOK FOR DEC 21 - 27, 2007 STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN WASHINGTON A A OREGON N A NRN CALIF N A SRN CALIF B N IDAHO N N NEVADA B N W MONTANA A B E MONTANA A B WYOMING N B UTAH B N ARIZONA B N COLORADO B N NEW MEXICO B A N DAKOTA A B S DAKOTA A B NEBRASKA A B KANSAS A N OKLAHOMA A A N TEXAS A A S TEXAS A A W TEXAS N A MINNESOTA A B IOWA A B MISSOURI A N ARKANSAS A A LOUISIANA A A WISCONSIN A B ILLINOIS A N MISSISSIPPI A A MICHIGAN A N INDIANA A A OHIO A A KENTUCKY A A TENNESSEE A A ALABAMA A N NEW YORK A A VERMONT A N NEW HAMP A N MAINE A N MASS A N CONN A A RHODE IS A A PENN A A NEW JERSEY A A W VIRGINIA A A MARYLAND A A DELAWARE A A VIRGINIA A A N CAROLINA A A S CAROLINA A N GEORGIA A N FL PNHDL A B FL PENIN A B AK N SLOPE B B AK ALEUTIAN B A AK WESTERN B B AK INT BSN B B AK S INT B N AK SO COAST B N AK PNHDL N 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. $$