861
FXUS06 KWBC 212010
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS, MD
300 PM EST FRI NOV 21 2008
6-10 DAY OUTLOOK FOR NOV 27 - DEC 01, 2008
AS HAS BEEN THE CASE OVER THE PAST COUPLE OF DAYS, THE MAJORITY OF THE
OPERATIONAL AND ENSEMBLE MODELS CONTINUE TO SUGGEST A 500-HPA PATTERN FEATURING
A RIDGE ACROSS THE NORTHERN ATLANTIC, A TROUGH ACROSS THE EASTERN U.S., A RIDGE
IN SOUTHWEST CANADA WITH ENERGY UNDERCUTTING THE RIDGE ACROSS THE SOUTHWEST
U.S., AND A TROUGH ACROSS WESTERN ALASKA. HOWEVER, THERE IS SOME DISAGREEMENT
AMONG THE MODELS IN THE DETAILS OF SOME OF THESE FEATURES. MOST OF THE MODELS
TODAY INDICATE A WEAKER RIDGE ACROSS SOUTHWEST CANADA AND A STRONGER TROUGH
ACROSS THE SOUTHWEST U.S. THAN WAS THE CONSENSUS YESTERDAY. HOWEVER, THE MODELS
ARE SPLIT INTO TWO DISTINCT CAMPS WITH THEIR HANDLING OF THE NORTH ATLANTIC
RIDGE AND EASTERN U.S. TROUGH. THE FIRST CAMP, CONSISTING OF THE GFS
SUPERENSEMBLE MEAN, THE 00Z AND 06Z GFS ENSEMBLE MEANS, THE CANADIAN ENSEMBLE
MEAN AND THE 00Z OPERATIONAL ECMWF ALL SUPPORT A STRONGER NORTH ATLANTIC RIDGE
AND AN OPEN TROUGH ACROSS THE EASTERN U.S. THE SECOND CAMP, CONSISTING OF THE
00Z AND 06Z OPERATIONAL GFS AND YESTERDAY'S 12Z ECMWF ENSEMBLE MEAN, INDICATE A
LESS-AMPLIFIED NORTH ATLANTIC RIDGE, WITH A CLOSED UPPER LOW OVER THE EAST. ON
THE BASIS OF CONTINUITY WITH THE OFFICIAL BLEND FROM YESTERDAY, THE OFFICIAL
FORECAST TODAY LEANS TOWARDS THE FIRST SOLUTION.
THE MAJORITY OF THE TOOLS ARE IN GOOD AGREEMENT ON THE TEMPERATURE
PROBABILITIES ACROSS THE COUNTRY, WITH FAIR TO GOOD AGREEMENT WITH REGARD TO
THE PRECIPITATION PROBABILITIES. THE CONSENSUS AMONG THE TOOLS NOW INDICATE
COLDER THAN AVERAGE TEMPERATURES ACROSS MUCH OF THE LOWER 48 STATES, WITH THE
EXCEPTION BEING THE NORTHERN PLAINS, WHERE MOST OF THE TOOLS SUGGEST NEAR
NORMAL TEMPERATURES. THIS SEEMS REASONABLE GIVEN THE TROUGH IN THE EAST AND
WITH LOWER HEIGHTS ACROSS THE WEST. GREATER THAN MEDIAN PRECIPITATION CHANCES
ARE WELL AGREED UPON ACROSS THE SOUTHWEST INTO THE SOUTHERN PLAINS BY THE
MAJORITY OF THE TOOLS, WITH DRIER THAN MEDIAN CONDITIONS EXPECTED ACROSS THE
NORTHWEST AND ACROSS THE SOUTHEAST. THERE ARE SOME DIFFERENCES IN REGARDS TO
PRECIPITATION CHANCES ACROSS THE NORTHEAST, WITH THE TOOLS SUGGESTING
NEAR-MEDIAN OR BELOW-MEDIAN PRECIPITATION CHANCES. THE OFFICIAL FORECAST CALLS
FOR NEAR-MEDIAN PRECIPITATION ACROSS THE NORTHEAST, AS A WEST-NORTHWESTERLY
UPPER FLOW IN THIS REGION RESULTS IN GENERALLY DRY CONDITIONS BUT ALSO LEAVES
OPEN THE POTENTIAL FOR SHORTWAVES/CLIPPER-TYPE SYSTEMS TO MOVE THROUGH THE MEAN
EASTERN TROUGH. WARMER AND WETTER CONDITIONS ARE WELL AGREED UPON ACROSS EAST
ALASKA AHEAD OF THE TROUGH FORECAST OVER WESTERN ALASKA.
TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 20 PERCENT OF TODAY'S OPERATIONAL
ECMWF CENTERED ON DAY 7...25 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8...20 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...30
PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...AND 5 PERCENT OF
TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8.
MODEL OF THE DAY: GFS SUPERENSEMBLE MEAN.
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 ON A SCALE OF 1 TO 5,
OWING TO FAIRLY CONSISTENT MODEL AGREEMENT OVER THE PAST COUPLE DAYS WITH THE
GENERAL 500-HPA PATTERN AND FAIR AGREEMENT FROM THE TOOLS, TEMPERED BY
DIFFERENCES IN THE HANDLING OF RIDGING ACROSS THE NORTH ATLANTIC AND TROUGHING
IN THE EASTERN U.S.
THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE THE CPC AUTOMATED TEMPERATURE
FORECAST, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM TEMPERATURE FORECAST,
KLEIN TEMPERATURE PROGS AND MODEL ANALOG TEMPERATURE SPECIFICATION COUNTS.
THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE THE NORTH AMERICAN ENSEMBLE
FORECAST SYSTEM PRECIPITATION FORECAST, THE CPC AUTOMATED PRECIPITATION
FORECAST, NEURAL NETWORKS, AND ANALOG PRECIPITATION SPECIFICATION COUNTS FROM
THE OPERATIONAL AND ENSEMBLE MODELS.
8-14 DAY OUTLOOK FOR NOV 29 - DEC 05, 2008
THERE IS REMARKABLE AGREEMENT AMONG THE ENSEMBLE MODELS TO THE GENERAL 500-HPA
PATTERN THROUGH THIS PERIOD. THE PATTERN LOOKS QUITE SIMILAR TO THE 6-10 DAY
PERIOD, FEATURING A RIDGE IN THE NORTH ATLANTIC, A TROUGH ACROSS THE EAST WITH
AN EXTENSION OF THE TROUGH BACK SOUTHWESTWARD ACROSS THE FOUR CORNERS REGION, A
RIDGE ENTERING THE WESTERN COAST OF CANADA, AND A TROUGH OVER THE BERING SEA.
THE ENSEMBLE CONSENSUS IS SIMILAR TO THE RUN OF THE 00Z OPERATIONAL GFS FROM
YESTERDAY. LITTLE CHANGE IN THE DETAILS OF MOST OF THESE FEATURES IS NOTED
COMPARED TO YESTERDAY, HOWEVER, ALL OF THE ENSEMBLES ARE IN AGREEMENT ON A
STRONGER SOUTHWEST U.S. TROUGH THAN WAS THE CONSENSUS YESTERDAY AND WITH A
LESS-PROGRESSIVE ALASKA TROUGH. TODAY'S 00Z OPERATIONAL GFS IS STILL SIMILAR TO
THE ENSEMBLE MEAN CONSENSUS, BUT IS MORE AMPLIFIED WITH THE RIDGE ACROSS THE
WEST COAST OF CANADA AND CLOSES OFF AN UPPER LOW OVER SOUTHERN CALIFORNIA. THE
06Z OPERATIONAL GFS IS STILL THE OUTLIER AMONG THE MODELS, RETURNING TO A
EASTERN U.S. TROUGH-THE 06Z RUN FROM YESTERDAY SHOWED MUCH OF THE EAST IN A
SOUTHWESTERLY, WARM ADVECTION REGIME-BUT IT DEPICTS A POWERFUL CLOSED LOW
OFFSHORE OF CALIFORNIA. THIS POWERFUL CLOSED LOW THAT THE 06Z OPERATIONAL GFS
SHOWS HAS NO SUPPORT FROM THE OTHER MODELS EXCEPT SOME SUPPORT FROM THE THE 00Z
OPERATIONAL GFS, WHICH, AS PREVIOUSLY INDICATED, HAS A MUCH WEAKER CLOSED UPPER
LOW OVER SOUTHERN CALIFORNIA.
THE TEMPERATURE AND PRECIPITATION CHANCES ACROSS THE U.S. FOR THIS PERIOD ARE
REASONABLY WELL AGREED UPON AMONG THE MAJORITY OF THE TOOLS. COLDER THAN NORMAL
TEMPERATURES ARE INDICATED ACROSS MUCH OF THE LOWER 48 STATES, WITH THE NOTABLE
EXCEPTION BEING THE NORTHERN PLAINS, WITH NEAR-NORMAL TEMPERATURE CHANCES
THERE. MUCH OF ALASKA SHOULD BE WARMER THAN AVERAGE IN THE WARM ADVECTION
REGIME AHEAD OF THE AFOREMENTIONED TROUGH. THE PACIFIC NORTHWEST AND WILL BE
DRIER THAN MEDIAN, WITH NEAR-MEDIAN PRECIP CHANCES ACROSS THE EAST AND THE
NORTHERN PLAINS STATES. ABOVE-MEDIAN PRECIP CHANCES ARE EXPECTED DOWNSTREAM OF
THE AFOREMENTIONED SOUTHWEST U.S. TROUGH ACROSS THE SOUTHWEST U.S. AND SOUTHERN
PLAINS, WITH ABOVE-MEDIAN PRECIPITATION ALSO EXPECTED OVER MUCH OF ALASKA OUT
AHEAD OF THE TROUGH ENTERING WESTERN ALASKA.
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 5 PERCENT OF TODAY'S OPERATIONAL
0Z GFS CENTERED ON DAY 11...25 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...35
PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...AND 15 PERCENT
OF TODAY'S CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 ON A SCALE OF
1 TO 5, OWING TO VERY GOOD AGREEMENT AMONGST THE ENSEMBLE MODELS AND WITH
REASONABLY GOOD AGREEMENT WITH THE TOOLS.
THE 8-14 DAY TEMPERATURE PROG IS BASED ON: THE NORTH AMERICAN ENSEMBLE FORECAST
SYSTEM TEMPERATURE FORECAST, THE CPC AUTOMATED FORECAST, AND ANALOG TEMPERATURE
COUNT SPECIFICATIONS FROM THE OPERATIONAL AND ENSEMBLE MODELS.
THE 8-14 DAY PRECIPITATION PROG IS BASED ON: THE CPC AUTOMATED PRECIPITATION
FORECAST, THE NORTH AMERICAN ENSEMBLE FORECAST SYSTEM PRECIPITATION FORECAST,
NEURAL NETWORK PRECIPITATION FORECASTS AND THE ANALOG PRECIPITATION
SPECIFICATION COUNTS FROM THE OPERATIONAL AND ENSEMBLE MODELS.
FORECASTER: ANDREW LOCONTO
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 18.
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:
19961111 - 19761104 - 19561130 - 19871120 - 19951123
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:
19961111 - 19761104 - 19561130 - 19621031 - 19661101
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 27 - DEC 01, 2008
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF N N
SRN CALIF B N IDAHO B B NEVADA B N
W MONTANA N B E MONTANA N B WYOMING B N
UTAH B N ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA N B S DAKOTA N B
NEBRASKA N N KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N B IOWA N N MISSOURI B N
ARKANSAS B A LOUISIANA B A WISCONSIN N N
ILLINOIS N N MISSISSIPPI B N MICHIGAN N N
INDIANA B N OHIO B N KENTUCKY B B
TENNESSEE B N ALABAMA B N NEW YORK B N
VERMONT B N NEW HAMP B N MAINE N N
MASS B N CONN B N RHODE IS B N
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B N FL PENIN B N AK N SLOPE A N
AK ALEUTIAN N N AK WESTERN A N AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 29 - DEC 05, 2008
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF B N
SRN CALIF B N IDAHO B B NEVADA B N
W MONTANA B B E MONTANA N B WYOMING B N
UTAH B N ARIZONA B N COLORADO B A
NEW MEXICO B A N DAKOTA N N S DAKOTA N N
NEBRASKA B N KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N N IOWA N N MISSOURI B N
ARKANSAS B N LOUISIANA B N WISCONSIN N N
ILLINOIS B N MISSISSIPPI B N MICHIGAN N N
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 N N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B N
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 N AK N SLOPE A N
AK ALEUTIAN N N AK WESTERN A N AK INT BSN A A
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.
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