000
FXUS06 KWBC 231900
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU MAY 23 2013
6-10 DAY OUTLOOK FOR MAY 29 - JUN 02, 2013
TODAY'S ENSEMBLE MEAN SOLUTIONS EXHIBIT GOOD AGREEMENT ON THE PREDICTED MEAN
500-HPA HEIGHTS FOR THE 6-10 DAY PERIOD OVER NORTH AMERICA. MOST SOLUTIONS
AGREE ON A 500-HPA TROUGH ALONG THE WEST COAST OF THE LOWER 48 STATES WITH A
500-HPA RIDGE OVER THE EASTARN CONUS. THE GFS AND ECMWF OPERATIONAL RUNS ARE IN
FAIRLY GOOD AGREEMENT WITH THEIR RESPECTIVE ENSEMBLE MEANS, ALTHOUGH THE
OPERATIONAL SOLUTIONS ARE GENERALLY MORE AMPLIFIED WITH THE MAIN CIRCULATION
FEATURES. THE ENSEMBLE SPAGHETTI DIAGRAMS INDICATE LOW TO MODERATE SPREAD
ACROSS THE MAJORITY OF THE FORECAST DOMAIN. MORE WEIGHTING WAS GIVEN TO THE 00Z
ECMWF ENSEMBLE MEAN BASED ON ITS SKILL DURING THE PAST 60 DAYS ASSESSED BY
ANOMALY CORRELATIONS.
TODAYS BLEND CHART INDICATES NEAR TO BELOW NORMAL HEIGHTS FOR THE WESTERN HALF
OF THE CONUS, WITH NEAR TO ABOVE NORMAL HEIGHTS EXPECTED OVER THE EASTERN HALF
OF THE CONUS.
ANOMALOUS UPPER-LEVEL TROUGHING LEADS TO ENHANCED CHANCES FOR BELOW NORMAL
TEMPERATURES OVER THE WESTERN PORTION OF THE LOWER 48 STATES. THERE ARE
INCREASED ODDS OF NEAR TO ABOVE NORMAL TEMPERATURES OVER MOST OF THE CENTRAL
AND EASTERN CONUS, WHICH IS PRIMARILY ATTRIBUTED TO PREDICTED ABOVE-NORMAL
500-HPA HEIGHTS ACCOMPANYING THE MAIN RIDGE, AND SOUTHERLY OR SOUTHWESTERLY
ANOMALOUS FLOW. THE FORECAST RIDGING AND ASSOCIATED POSITIVE 500-HPA HEIGHT
ANOMALIES OVER ALASKA LEAD TO ENHANCED PROBABILITIES FOR ABOVE NORMAL
TEMPERATURES FOR THIS AREA.
ANOMALOUS UPPER-LEVEL TROUGHING OVER THE WEST AND ITS ASSOCIATED JET FAVOR
ABOVE MEDIAN PRECIPITATION FOR MOST OF THE NORTHERN TIER OF THE U.S. EXTENDING
FROM PACIFIC NORTHWEST EASTWARD THROUGH THE NORTHERN PLAINS TO THE GREAT LAKES.
UPPER-LEVEL RIDGING INCREASES THE ODDS FOR BELOW MEDIAN PRECIPITATION FROM THE
SOUTHWEST ACROSS THE SOUTHERN PLAINS TO THE SOUTHEAST. BELOW MEDIAN
PRECIPITATION IS FAVORED FOR MOST OF ALASKA.
TODAY'S 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...10 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...10
PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8...20 PERCENT OF
TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 8...25 PERCENT OF TODAY'S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8...AND 15 PERCENT OF TODAY'S 0Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8.
MODEL OF THE DAY: TODAY'S 00Z ECMWF ENSEMBLE MEAN
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE MODELS AND DERIVED TOOLS.
8-14 DAY OUTLOOK FOR MAY 31 - JUN 06, 2013
TODAY'S ENSEMBLE MEAN SOLUTIONS EXHIBIT GOOD AGREEMENT ON THE EXPECTED MEAN
500-HPA CIRCULATION PATTERN OVER NORTH AMERICA AND VICINITY FOR THE 8-14
DAY PERIOD. THE MAIN CIRCULATION FEATURES DEPICTED BY THE ENSEMBLE MEANS
INCLUDE A 500-HPA HEIGHT RIDGE OVER THE EAST-CENTRAL CONUS AND A TROUGH OVER
THE WEST COAST OF THE CONUS. THE GFS OPERATIONAL RUNS ARE IN FAIRLY GOOD
AGREEMENT WITH THEIR RESPECTIVE ENSEMBLE MEANS, ALTHOUGH THE OPERATIONAL
SOLUTIONS ARE GENERALLY MORE AMPLIFIED WITH THE MAIN CIRCULATION FEATURES. THE
ENSEMBLE SPAGHETTI DIAGRAMS INDICATE LOW TO MODERATE SPREAD ACROSS THE MAJORITY
OF THE FORECAST DOMAIN. TODAY'S WEEK 2 UPPER-LEVEL HEIGHT MANUAL BLEND FAVORS
THE 00Z ECMWF ENSEMBLE MEAN SOLUTION.
THE PRECIPITATION AND TEMPERATURE PATTERNS IN THE WEEK 2 PERIOD ARE EXPECTED TO
BE VERY SIMILAR TO THAT FROM THE 6-10 DAY PERIOD, ONLY LOWER PROBABILITIES.
ANOMALOUS UPPER-LEVEL TROUGHING LEADS TO ENHANCED CHANCES FOR BELOW NORMAL
TEMPERATURES OVER THE WESTERN PORTION OF THE LOWER 48 STATES. THERE ARE
INCREASED ODDS OF NEAR TO ABOVE NORMAL TEMPERATURES OVER MOST OF THE CENTRAL
AND EASTERN CONUS, WHICH IS PRIMARILY ATTRIBUTED TO PREDICTED ABOVE-NORMAL
500-HPA HEIGHTS ACCOMPANYING THE MAIN RIDGE, AND SOUTHERLY OR SOUTHWESTERLY
ANOMALOUS FLOW.
ANOMALOUS UPPER-LEVEL TROUGHING OVER THE WEST AND ITS ASSOCIATED JET FAVOR
ABOVE MEDIAN PRECIPITATION FOR MOST OF THE NORTHERN TIER OF THE U.S.
UPPER-LEVEL RIDGING INCREASES THE ODDS FOR BELOW MEDIAN PRECIPITATION FROM THE
SOUTHWEST ACROSS THE SOUTHERN PLAINS TO THE SOUTHEAST.
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...10 PERCENT OF TODAY'S 0Z GFS ENSEMBLE MEAN CENTERED ON
DAY 11...10 PERCENT OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 11...20
PERCENT OF TODAY'S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 11...25 PERCENT OF
TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11...AND 15 PERCENT OF
TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11.
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO GOOD AGREEMENT AMONG THE MODELS AND DERIVED TOOLS.
FORECASTER: LUKE HE
NOTES:
AUTOMATED FORECASTS ARE ISSUED ON SATURDAY AND SUNDAY. OCCASIONALLY MANUAL
INTERVENTION IS NECESSARY TO ADDRESS QUALITY CONTROL AND CONSISTENCY ISSUES.
IN THESE CASES, FORECASTS ARE MANUALLY DRAWN BUT A FULL DISCUSSION IS NOT
ISSUED.
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
THE TEMPERATURE MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING WARMER
(ORANGE, \"A\"), COLDER (BLUE, \"B\"), OR CLOSE TO (UNSHADED, \"N\")
HISTORICAL AVERAGE VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, \"F\"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
THE PRECIPITATION MAP SHOWS REGIONS WITH > 33% CHANCE OF BEING
WETTER (GREEN, \"A\"), DRIER (TAN, \"B\"), OR CLOSE TO (UNSHADED, \"N\")
HISTORICAL MEDIAN VALUES FOR THE CALENDAR PERIOD OF THE FORECAST
(DASHES, \"INCHES\"). LABELS ON THE SHADED LINES GIVE THE PROBABILITY
(> 33%) OF THE MORE LIKELY CATEGORY (B OR A). PROBABILITY OF N IS
ALWAYS < 40%.
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 CLIMATE PREDICTION CENTER USES 1981-2010 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
JUNE 20
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:
19910519 - 19620520 - 19990513 - 20050603 - 19620601
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:
19910519 - 19990513 - 19620521 - 20030505 - 19960529
|
