867
FXUS06 KWBC 261916
PMDMRD
PROGNOSTIC DISCUSSIONS FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER CAMP SPRINGS MD
300 PM EDT TUE AUG 26 2008
6-10 DAY OUTLOOK VALID FOR SEP 01 - 05 2008
SIMILAR TO YESTERDAY, THE ENSEMBLE MEAN SOLUTIONS ARE IN VERY GOOD AGREEMENT
FOR THE EXPECTED 500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. AN EXCEPTION,
HOWEVER, IS THE 00Z CANADIAN ENSEMBLE WHICH DEVIATES CONSIDERABLY ESPECIALLY
ACROSS THE EASTERN TWO-THIRDS OF THE US AND THIS MODEL WAS NOT INCLUDED IN THE
OFFICIAL BLEND FOR TODAY. THE ECMWF ENSEMBLE MEAN DATA YESTERDAY INDICATED
LARGER DIFFERENCES THAN THE GFS SUITE OF PRODUCTS BY MAINTAINING A CUTOFF LOW
OFF OF THE NORTHEAST US. TODAY, HOWEVER, THE ECMWF RUNS HAVE COME INTO CLOSER
AGREEMENT WHICH INCREASES CONFIDENCE DURING THIS PERIOD. OPERATIONAL RUNS OF
THE GFS DURING THE PAST 24 HOURS CONTINUE TO VARY WIDELY ACROSS SEVERAL AREAS
OF THE FORECAST DOMAIN AND AGAIN WERE NOT INCLUDED IN THE OFFICIAL BLEND
SOLUTION WHICH WAS PARTITIONED BETWEEN THE GFS SUPERENSEMBLE AND 00Z AND 06Z
ENSEMBLE MEAN SOLUTIONS. BASED ON THE ABOVE APPROACH, A STRONG TROUGH IS
EXPECTED TO SITUATE ITSELF ALONG THE US WEST COAST WITH A RATHER STRONG RIDGE
ACROSS THE EASTERN 2/3 OF THE COUNTRY. AS A RESULT OF THIS FORECAST PATTERN,
ABOVE-AVERAGE TEMPERATURES AND BELOW-MEDIAN PRECIPITATION ARE EXPECTED TO
PREVAIL FROM THE NORTH-CENTRAL US TO PARTS OF THE NORTHEAST US DUE TO THE
STRONG RIDGE AND ABOVE-AVERAGE HEIGHTS IN THIS AREA. FAVORABLE ORIENTATION OF
SUB-TROPICAL RIDGING ACROSS THE ATLANTIC BASIN WILL ALLOW NUMEROUS TROPICAL
DISTURBANCES AND CONTINUED AMPLE MOISTURE FLOW TO IMPACT THE GULF COAST INTO
THE SOUTHWEST US INTO THE INTER-MOUNTAIN WEST WITH ABOVE-MEDIAN PRECIPITATION
DURING THE PERIOD. MOREOVER, THE MEAN TROUGH ALONG THE WEST COAST SHOULD LEAD
TO COOLER THAN AVERAGE TEMPERATURES ACROSS PARTS OF THE PACIFIC NORTHWEST.
TODAYS OFFICIAL 500-HPA BLEND CONSISTS OF 30 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...AND 50 PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8.
MODEL(S) OF THE DAY: GFS SUPERENSEMBLE
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD IS ABOVE AVERAGE, 4 ON A SCALE OF 1
TO 5, DUE TO GOOD MODEL AND FORECAST TOOL AGREEMENT. THE EVOLUTION OF TROPICAL
SYSTEMS ACROSS THE SOUTHERN TIER INCREASES THE UNCERTAINTY IN THIS REGION
DURING THE PERIOD.
THE 6-10 DAY TEMPERATURE PROG IS BASED ON THE KLEIN AND ANALOG SPECIFICATIONS
FROM THE OFFICIAL BLEND, THE AUTO TEMPERATURE FORECAST, THE NORTH AMERICAN
ENSEMBLE FORECAST SYSTEM (NAEFS) TEMPERATURE PROBABILITY FORECASTS, THE KLEIN
PROBABILITIES FROM THE VARIOUS ENSEMBLES, AND UNCALIBRATED AND CALIBRATED
TEMPERATURES FROM THE GFS ENSEMBLE MEAN.
THE 6-10 DAY PRECIPITATION PROG IS BASED ON THE ANALOG AND NEURAL NET
SPECIFICATIONS FROM THE OFFICIAL BLEND, THE AUTO PRECIPITATION FORECAST, THE
NORTH AMERICAN ENSEMBLE FORECAST SYSTEM (NAEFS) PRECIPITATION PROBABILITY
FORECASTS, AND NEURAL NET PROBABILITIES FROM THE VARIOUS ENSEMBLES.
8-14 DAY OUTLOOK FOR SEP 03 - 09 2008:
FOR WEEK 2, THERE IS REASONABLY GOOD AGREEMENT BETWEEN THE ENSEMBLE MEAN
SOLUTIONS WHICH GENERALLY REFLECT A SLIGHTLY DEAMPLIFIED 500-HPA PATTERN THAN
THAT SHOWN FOR THE 6-10 DAY PERIOD. THE MAIN FEATURES DURING THE 6-10 DAY
PERIOD ARE ALSO EXPECTED TO BE IN PLACE DURING THIS FORECAST PERIOD. THERE WILL
CONTINUE TO BE A TROUGH ALONG THE US WEST COAST WITH A STRONG RIDGE ACROSS THE
EASTERN TWO-THIRDS OF THE COUNTRY. THE MAIN DIFFERENCE DURING THIS PERIOD FROM
THE 6-10 DAY PERIOD IS THE SUBSTANTIALLY DECREASED AGREEMENT IN THE FORECAST
TOOLS ESPECIALLY FOR PRECIPITATION. THEREFORE CONFIDENCE IS LOWER FOR THE WEEK
2 PERIOD. THE OFFICIAL BLEND IS BASED ON THE GFS SUPERENSEMBLE AND 00Z AND 06Z
ENSEMBLE MEAN SOLUTIONS. ABOVE-AVERAGE TEMPERATURES ARE EXPECTED TO CONTINUE
ACROSS MUCH OF THE NORTH-CENTRAL US, GREAT LAKES AND NORTHEAST US DUE TO THE
CONTINUATION OF THE RIDGE IN THIS AREA BUT DUE TO GREATER VARIABILITY IN THE
FORECAST TOOLS, PROBABILITIES ARE SOMEWHAT LOWER. BELOW-AVERAGE TEMPERATURES
ARE EXPECTED ACROSS PARTS OF THE PACIFIC NORTHWEST, SOUTHWEST US, AND ALONG THE
GULF COAST. OTHER THAN THE NORTHWEST US, THE BELOW-AVERAGE TEMPERATURES ARE
GENERALLY RELATED TO ANTICIPATED INCREASED CLOUD COVER AND PRECIPITATION.
ABOVE-MEDIAN PRECIPITATION IS EXPECTED TO CONTINUE DURING THIS PERIOD ACROSS
THE GULF COAST AND PARTS OF THE SOUTHWEST US DUE TO THE LIKELY CONTINUATION OF
TROPICAL DISTURBANCES AND TROPICAL MOISTURE IN GENERAL. THE ABOVE-MEDIAN
PRECIPITATION IS LIKELY TO BE ORIENTED SLIGHTLY NORTHEASTWARD DURING THIS
PERIOD. BELOW-MEDIAN PRECIPITATION IS EXPECTED TO BE FOCUSED ACROSS THE
NORTHEAST US.
THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF 30 PERCENT OF YESTERDAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 10...20 PERCENT OF YESTERDAY'S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 10...AND 50 PERCENT OF YESTERDAY'S GFS SUPERENSEMBLE MEAN
CENTERED ON DAY 10.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS NEAR AVERAGE, 3 ON A SCALE OF 1
TO 5 DUE TO GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFFSET BY
RELATIVELY POOR AGREEMENT AMONG THE FORECAST TOOLS. LARGE UNCERTAINTY EXISTS
FOR FUTURE DEVELOPMENTS IN THE TROPICS.
THE 8-14 DAY TEMPERATURE PROG IS BASED ON THE KLEIN AND ANALOG SPECIFICATIONS
FROM THE OFFICIAL BLEND, THE AUTO TEMPERATURE FORECAST, THE NORTH AMERICAN
ENSEMBLE FORECAST SYSTEM (NAEFS) TEMPERATURE PROBABILITY FORECASTS, AND THE
KLEIN PROBABILITIES FROM THE GFS AND CANADIAN ENSEMBLES.
THE 8-14 DAY PRECIPITATION PROG IS BASED ON THE NEURAL NET SPECIFICATION FROM
THE OFFICIAL BLEND, NORTH AMERICAN ENSEMBLE FORECAST SYSTEM (NAEFS)
PRECIPITATION PROBABILITY FORECASTS, THE AUTO BLEND PRECIPITATION FORECAST, AND
THE CDC PRECIPITATION FORECAST.
FORECASTER: GOTTSCHALCK
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
SEPTEMBER 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:
19710908 - 19990825 - 19670909 - 19760827 - 19700814
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:
19710908 - 19990825 - 19760826 - 19610830 - 19670903
6 TO 10 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 01 - 05, 2008
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF N N
SRN CALIF N N IDAHO B N NEVADA B N
W MONTANA N N E MONTANA N N WYOMING N N
UTAH B A ARIZONA B A COLORADO N A
NEW MEXICO B A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS N N OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI A N
ARKANSAS N A LOUISIANA B A WISCONSIN A B
ILLINOIS A B MISSISSIPPI B A MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A N
TENNESSEE A N ALABAMA N A NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A N
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A B W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA A B
N CAROLINA N N S CAROLINA N N GEORGIA N A
FL PNHDL B A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N N
AK S INT N N AK SO COAST N N AK PNHDL N N
8 TO 14 DAY OUTLOOK TABLE
OUTLOOK FOR SEP 03 - 09, 2008
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B N NRN CALIF N N
SRN CALIF N N IDAHO B N NEVADA B N
W MONTANA N N E MONTANA N N WYOMING N N
UTAH B N ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA A N S DAKOTA A A
NEBRASKA N A KANSAS N A OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS N A LOUISIANA B A WISCONSIN A N
ILLINOIS A N MISSISSIPPI N A MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA N A NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A B W VIRGINIA A N
MARYLAND A B DELAWARE A B VIRGINIA A N
N CAROLINA A N S CAROLINA N N GEORGIA N N
FL PNHDL B A FL PENIN B A AK N SLOPE A N
AK ALEUTIAN N A AK WESTERN A A AK INT BSN A N
AK S INT A A AK SO COAST N A 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.
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