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FXUS06 KWBC 081902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON MAY 08 2023
6-10 DAY OUTLOOK FOR MAY 14 - 18 2023
DYNAMICAL MODELS ARE IN GOOD AGREEMENT REGARDING AN AMPLIFIED 500-HPA
GEOPOTENTIAL HEIGHT PATTERN ACROSS THE FORECAST DOMAIN DURING THE 6-10 DAY
PERIOD. RIDGING IS PREDICTED ACROSS WESTERN NORTH AMERICA AND MUCH OF ALASKA,
WITH A TREND TOWARD MORE TROUGHING IN THE EAST BY THE END OF THE PERIOD AS
MID-LEVEL LOW PRESSURE DEVELOPS ACROSS NORTHEASTERN CANADA. THE ASSOCIATED
DECREASING MID-LEVEL HEIGHTS OVER THE EASTERN CONUS TELECONNECT WITH THE
UPSTREAM RIDGING TO THE WEST AS WELL AS THE MADDEN JULIAN OSCILLATION (MJO)
PROPAGATING INTO PHASES 7 AND 8. TODAY’S MANUAL 500-HPA HEIGHT BLEND DEPICTS
ABOVE NORMAL HEIGHTS ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS, ALONG WITH
ALASKA. NEAR NORMAL HEIGHTS ARE DEPICTED ACROSS MUCH OF THE EASTERN AND
SOUTHERN TIER OF THE CONUS, WITH BELOW NORMAL HEIGHTS FAVORED ACROSS THE
NORTHEAST.
EARLY IN THE PERIOD, DAILY RECORD HIGH TEMPERATURES ARE POSSIBLE ACROSS THE
PACIFIC NORTHWEST UNDERNEATH AMPLIFIED RIDGING, WITH THE NATIONAL BLEND OF
MODELS INDICATING TEMPERATURES OVER SOME LOW ELEVATION AREAS EXCEEDING 90 DEG
F. WHILE SOME MODERATION IS FORECAST LATER IN THE PERIOD, THE OVERALL PATTERN
SUPPORTS HIGH PROBABILITIES (GREATER THAN 80 PERCENT) FOR ABOVE-NORMAL
TEMPERATURES ACROSS PARTS OF THE PACIFIC NORTHWEST AND GREAT BASIN, WITH
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES REMAINING ELEVATED THROUGHOUT MUCH
OF THE WEST AND NORTHERN PLAINS. THE PATTERN IN THE EAST IS FORECAST TO BE MORE
TRANSITIONAL, AS TROUGHING INCREASES TOWARD DAY-10. THE HIGHEST PROBABILITIES
FOR BELOW-NORMAL TEMPERATURES ARE FORECAST ACROSS THE SOUTHERN PLAINS DUE TO
ENHANCED RAINFALL FORECAST BEFORE AND DURING THE FORECAST PERIOD. ENHANCED
CHANCES FOR BELOW-NORMAL TEMPERATURES ARE ALSO DEPICTED ACROSS PARTS OF THE
GREAT LAKES, OHIO VALLEY, AND NORTHEAST, CLOSER TO THE TROUGH AXIS OVER EASTERN
CANADA. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE ELEVATED ACROSS PARTS
OF THE SOUTHERN MID-ATLANTIC AND SOUTHEAST TIED TO RELATIVELY WARMER
TEMPERATURES FORECAST EARLY IN THE PERIOD. RIDGING ACROSS ALASKA GENERALLY
SUPPORTS ENHANCED PROBABILITIES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES ACROSS
THE STATE, WITH THE EXCEPTION OF PARTS OF THE SOUTH-CENTRAL MAINLAND WHERE
BELOW-NORMAL TEMPERATURES ARE FAVORED DUE TO INCREASED CLOUD COVER AND
PRECIPITATION CHANCES.
RIDGING FAVORS INCREASED PROBABILITIES OF BELOW-NORMAL PRECIPITATION ACROSS
PARTS OF THE NORTHWEST CONUS AND NORTH-CENTRAL CONUS. AN ANOMALOUS CYCLONIC
MID-LEVEL CIRCULATION IS FORECAST TO DEVELOP UNDERNEATH THE RIDGE AXIS, ACROSS
NORTHERN MEXICO OR THE EASTERN PACIFIC SOUTH OF CALIFORNIA, WHICH FAVORS
INCREASING CHANCES FOR PRECIPITATION ACROSS CLIMATOLOGICALLY DRY AREAS OF THE
SOUTHWESTERN CONUS. THIS IN TURN FAVORS HIGH PROBABILITIES OF ABOVE-NORMAL
PRECIPITATION OVER THESE AREAS (GREATER THAN 70 PERCENT OVER PARTS OF ARIZONA
AND NEW MEXICO), WITH ELEVATED PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION
EXTENDING THROUGH THE SOUTHERN PLAINS AND MUCH OF THE EASTERN CONUS AS
SOUTHERLY FLOW AND MOISTURE ADVECTION INCREASE AHEAD OF BUILDING TROUGHING.
WEAK TROUGHING FORECAST OVER THE BERING SEA FAVORS ELEVATED PROBABILITIES FOR
ABOVE-NORMAL PRECIPITATION ACROSS ALASKA, WITH THE EXCEPTION OF PARTS OF
SOUTHEAST ALASKA WHERE PROBABILITIES FOR BELOW-NORMAL PRECIPITATION ARE
INCREASED.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 30% OF TODAY'S 0Z CANADIAN
ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT REGARDING AN AMPLIFIED PATTERN ACROSS NORTH AMERICA,
OFFSET BY SOME TRANSITION ACROSS THE EAST TOWARD THE END OF THE PERIOD.
8-14 DAY OUTLOOK FOR MAY 16 - 22 2023
THE 500-HPA HEIGHT PATTERN DURING WEEK-2 IS SIMILAR TO THAT OF THE 6-10 DAY
PERIOD, RESULTING IN A LARGELY PERSISTENT AND SIMILAR FORECAST. RIDGING REMAINS
FAVORED ACROSS WESTERN NORTH AMERICA, WITH TROUGHING PREDICTED OVER EASTERN
CANADA, ALTHOUGH THE AMPLITUDE OF THESE FEATURES IS WEAKER COMPARED TO THE 6-10
DAY PERIOD. THE WEEK-2 MANUAL HEIGHT BLEND DEPICTS ABOVE-NORMAL HEIGHTS ACROSS
THE WEST AND EXTENDING THROUGH ALASKA, AND NEAR-NORMAL HEIGHTS ACROSS MUCH OF
THE EAST. THE LARGEST NEGATIVE HEIGHT ANOMALIES ARE PREDICTED ACROSS EASTERN
CANADA, WITH SLIGHTLY BELOW-NORMAL HEIGHTS EXTENDING INTO THE GREAT LAKES AND
NORTHEAST.
INCREASED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES CONTINUE TO BE FORECAST
ACROSS MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS UNDERNEATH ANOMALOUS
RIDGING. CONVERSELY, PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE ELEVATED
ACROSS PARTS OF THE SOUTHERN PLAINS DUE TO INCREASED PRECIPITATION FORECAST.
THE TROUGHING OVER EASTERN CANADA SUPPORTS ELEVATED CHANCES OF BELOW-NORMAL
TEMPERATURES ACROSS THE EAST-CENTRAL CONUS WITH MULTIPLE SHORTWAVES AND FRONTAL
SYSTEMS POSSIBLY MOVING ACROSS THE REGION. ENHANCED CHANCES OF ABOVE-NORMAL
TEMPERATURES ARE FORECAST ACROSS PARTS OF THE SOUTHEAST AND EASTERN NEW
ENGLAND, AHEAD OF THE MEAN FRONTAL BOUNDARY AND UNDERNEATH MORE SOUTHERLY
MID-LEVEL FLOW. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE INCREASED
ACROSS SOUTHEAST ALASKA AND NORTHEASTERN MAINLAND ALASKA, CONSISTENT WITH THE
ECMWF AND GEFS REFORECAST TOOLS, AND POSITIVE HEIGHT ANOMALIES. DESPITE HIGHER
HEIGHTS, INCREASED PRECIPITATION FAVORS NEAR TO BELOW-NORMAL TEMPERATURES
ACROSS SOUTHWEST ALASKA.
INCREASED PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION REMAIN FAVORED ACROSS
MUCH OF THE SOUTHWEST TIED TO THE AFOREMENTIONED CYCLONIC CIRCULATION PREDICTED
UNDERNEATH THE RIDGING TO THE NORTH. OCCASIONAL FRONTAL SYSTEMS ROTATING
THROUGH THE TROUGHING FAVOR ELEVATED CHANCES OF ABOVE-NORMAL PRECIPITATION
ACROSS THE SOUTHEAST. ANOMALOUS NORTHERLY MID-LEVEL FLOW FAVORS INCREASED
CHANCES FOR BELOW-NORMAL PRECIPITATION ACROSS MUCH OF THE NORTHERN TIER OF THE
CONUS, WITH THE HIGHEST PROBABILITIES ACROSS THE UPPER MIDWEST. ELEVATED
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE FORECAST ACROSS ALASKA DUE TO
INCREASED SOUTHERLY FLOW ASSOCIATED WITH WEAK TROUGHING PERSISTING OVER THE
BERING SEA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 30% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
A GENERALLY PERSISTENT FORECAST FROM THE 6-10 DAY PERIOD, OFFSET BY SOME
DECREASE IN AMPLIFICATION.
FORECASTER: THOMAS COLLOW
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 1991-2020 BASE PERIOD MEANS AS REFERENCE IN
THE CLIMATE OUTLOOKS.
THE NEXT SET OF LONG-LEAD MONTHLY AND SEASONAL OUTLOOKS WILL BE RELEASED ON MAY
18.
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:
19510502 - 19980511 - 19750502 - 19750507 - 20030423
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:
19510502 - 19980512 - 19750506 - 19940518 - 19750430
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 14 - 18 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A B NEVADA A A
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A A ARIZONA A A COLORADO B A
NEW MEXICO B A N DAKOTA A B S DAKOTA A B
NEBRASKA N B KANSAS B B OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA N B MISSOURI N B
ARKANSAS B N LOUISIANA B A WISCONSIN N B
ILLINOIS N B MISSISSIPPI N A MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY N N
TENNESSEE N A ALABAMA A A NEW YORK B N
VERMONT B N NEW HAMP N N MAINE N N
MASS N N CONN N N RHODE IS N N
PENN B N NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 16 - 22 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A N NEVADA A A
W MONTANA A B E MONTANA A B WYOMING A N
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO B A N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS N N OKLAHOMA B N
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N B IOWA N B MISSOURI B B
ARKANSAS B N LOUISIANA B A WISCONSIN N B
ILLINOIS B B MISSISSIPPI B A MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B N
TENNESSEE B N ALABAMA B A NEW YORK B B
VERMONT N N NEW HAMP N N MAINE N N
MASS A N CONN N N RHODE IS A N
PENN N B NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT B A AK SO COAST B 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
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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