942
FXUS06 KWBC 191902
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 19 2025
6-10 DAY OUTLOOK FOR MAY 25 - 29 2025
TODAY'S MODEL SOLUTIONS ARE IN DECENT AGREEMENT. A FAIRLY AMPLIFIED 500-HPA
PATTERN SHOULD BE IN PLACE AT THE START OF THE PERIOD WHICH WILL SLOWLY
DEAMPLIFY AS THE PERIOD PROGRESSES. THE MANUAL 500-HPA HEIGHT BLEND IS BASED
PRIMARILY ON THE OPERATIONAL ECMWF AND EUROPEAN ENSEMBLE MEANS, WITH
CONTRIBUTIONS FROM THE GEFS AND CANADIAN ENSEMBLE AS WELL. THE OPERATIONAL
ECMWF WAS INCLUDED TO ADD MORE AMPLITUDE TO THE PATTERN WHICH MAY BE GETTING
ERRONEOUSLY FLATTENED BY OUTLIER MEMBERS IN THE ENSEMBLES. THE RESULTANT MANUAL
BLEND FEATURES MID-LEVEL RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS CENTERED OVER
CENTRAL CANADA AND EXTENDING SOUTHWESTWARD THROUGH MOST OF THE WESTERN
CONTIGUOUS UNITED STATES (CONUS). MEANWHILE, A MID-LEVEL TROUGH AND
BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST FARTHER SOUTHEAST CENTERED OVER THE
NORTHEASTERN CONUS. THE MEAN 5-DAY ANOMALY ASSOCIATED WITH THIS TROUGH IS
CONSIDERABLY WEAKER THAN IN FORECASTS FROM THE PAST SEVERAL DAYS, CONSISTENT
WITH THE ANTICIPATED DEAMPLIFICATION OF THE PATTERN WHICH SHOULD BE WELL
UNDERWAY BY THE END OF THE PERIOD. TO THE WEST, A FAIRLY STRONG MID-LEVEL
TROUGH IS EXPECTED TO COVER MOST OF ALASKA, WITH THE MOST ANOMALOUS 500-HPA
HEIGHTS (-9 TO -15 DM) COVERING SOUTHERN PARTS OF THE STATE AND THE ADJACENT
GULF OF ALASKA. SLIGHTLY BELOW-NORMAL 500-HPA HEIGHTS ARE PREDICTED ACROSS
HAWAII BY MOST TOOLS.
MEAN SURFACE LOW PRESSURE SHOULD BE CENTERED SOMEWHERE OVER THE WESTERN NORTH
ATLANTIC WITH HIGHER PRESSURES FARTHER TO THE WEST OVER AND NORTH OF THE GREAT
LAKES, UPSTREAM FROM THE MEAN MID-LEVEL TROUGH. THIS SHOULD ESTABLISH
SLOWLY-MODERATING BUT BELOW-NORMAL TEMPERATURES INTO MOST OF THE CENTRAL AND
EASTERN CONUS OUTSIDE THE NORTHERN AND SOUTHERN FRINGES OF THIS REGION. THE
TOOLS ARE IN FAIR TO GOOD AGREEMENT PLACING THE BEST CHANCES FOR SUB-NORMAL
TEMPERATURES (OVER 50 PERCENT) FROM THE MIDDLE MISSISSIPPI VALLEY EASTWARD
ACROSS THE LOWER GREAT LAKES, STRETCHING AS FAR SOUTH AND EAST AS THE OHIO
RIVER. CONSISTENT WITH THE LOWER MID-LEVEL TROUGH AMPLITUDE, IT SHOULD BE NOTED
THAT THESE ODDS ARE CONSIDERABLY LOWER THAN IN FORECASTS FROM LATE LAST WEEK,
WHEN CHANCES FOR BELOW-NORMAL TEMPERATURES TOPPED 70 PERCENT IN SOME AREAS.
MEANWHILE, ABOVE-NORMAL TEMPERATURES ARE ANTICIPATED FOR MOST OF THE WESTERN
CONUS UNDER MID-LEVEL RIDGING, EXCEPT ALONG THE IMMEDIATE WEST COAST, WHERE
MEAN NORTH TO NORTHWESTELY SURFACE FLOW IS EXPECTED, AND HEIGHTS WILL BE CLOSER
TO NORMAL. WARMER THAN NORMAL CONDITIONS ARE FAVORED ACROSS HAWAII, CONSISTENT
WITH THE CONSOLIDATION, BUT THERE IS MORE UNCERTAINTY ACROSS ALASKA, ESPECIALLY
THE SOUTHERN TIER. RAW ENSEMBLE MEAN OUTPUTS SHOW GREATLY ENHANCED ODDS FOR
SUB-NORMAL TEMPERATURES ACROSS THE SOUTHERN MAINLAND AND SOUTHEASTERN SECTIONS,
BUT THE BIAS-CORRECTED VERSIONS REDUCE THE ANOMALIES SOMEWHAT. THE REFORECAST
TOOLS, HOWEVER, ARE CONSIDERABLY MILDER. THE GEFS REFORECAST SLIGHTLY FAVORS
COOLER THAN NORMAL WEATHER WHILE THE CANADIAN ENSEMBLE REFORECAST DEPICTS
INCREASED ODDS FOR ABOVE-NORMAL TEMPERATURES THERE. THE EUROPEAN ENSEMBLE
REFORECAST FAVORS NEITHER TEMPERATURE EXTREME. THE ALASKA TEMPERATURE FORECAST
IS A COMPROMISE OF THE TOOLS, FAVORING COOLER THAN NORMAL CONDITIONS IN
SOUTH-CENTRAL AND SOUTHEASTERN ALASKA, BUT WITH LOWER CHANCES THAN DEPICTED BY
THE CONSOLIDATION AND THE AUTO BLEND.
ABOVE-NORMAL PRECIPITATION IS FAVORED OVER MUCH OF THE SOUTH-CENTRAL AND
SOUTHEASTERN CONUS, NORTHWARD ALONG THE EAST COAST. ENSEMBLE MEAN SURFACE
PRESSURE FORECASTS ALL SHOW A DECENT INFLOW OF MOISTURE FROM THE GULF INTO THE
SOUTH-CENTRAL AND SOUTHEASTERN CONUS WHILE SURFACE HIGH PRESSURE OVER AND/OR
NEAR THE GREAT LAKES. WHERE THE CIRCULATION FROM THESE TWO FEATURES MEET, A
WAVERING DE FACTO FRONT WILL BECOME ESTABLISHED OVER THE SOUTHEAST WHICH SHOULD
SERVE AS A FOCUS FOR ENHANCED RAINFALL. SLIGHTLY REDUCED ODDS FOR HEAVIER THAN
NORMAL PRECIPITATION EXTENDS NORTHWARD ALONG THE EAST COAST INTO ADJACENT
CANADA NEAR THE SLOWLY DEAMPLIFYING MID-LEVEL TROUGH, WHICH SHOULD BE DRIFTING
EASTWARD. ANALOGS AND AUTO BLENDS FAVOR THE HEAVIER PRECIPITATION EXTENDING
CONSIDERABLY NORTHWARD INTO THE DAKOTAS, BUT THE ENHANCED ODDS WILL DECREASE TO
THE NORTH. MEANWHILE, ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED ALONG PARTS OF
THE WEST COAST CONSISTENT WITH CYCLONIC MID-LEVEL FLOW BETWEEN THE ANOMALOUSLY
HIGH 500-HPA HEIGHTS IN THE INTERIOR WEST AND THE FAIRLY STRONG TROUGH
EXTENDING EASTWARD FROM SOUTH OF ALASKA. IN THE CONUS, INCREASED ODDS FOR DRIER
THAN NORMAL CONDITIONS ARE LIMITED TO PORTIONS OF THE GREAT LAKES AND ADJACENT
AREAS NEAR MEAN SURFACE HIGH PRESSURE. CONSISTENT WITH THE CONSOLIDATION, ODDS
LEAN TOWARD WET WEATHER ACROSS HAWAII, AND NEAR TO NORTH OF THE FORECAST TROUGH
NEAR ALASKA, MOST OF THE STATE IS EXPECTING WETTER THAN NORMAL CONDITIONS,
ESPECIALLY IN SOUTHEASTERN PARTS OF THE STATE, WHERE ODDS FOR SURPLUS
PRECIPITATION EXCEED 50 PERCENT.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 17% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, 30% OF TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND
18% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: SLIGHTLY ABOVE AVERAGE, 4 OUT OF
5. GOOD AGREEMENT ON THE HEIGHT PATTERN AMONG THE ENSEMBLE MEANS IS OFFSET
SLIGHTLY BY SOME AREAS OF INCONSISTENCY AMONG THE DYNAMICAL AND STATISTICAL
TEMPERATURE AND PRECIPITATION TOOLS, AND BY SLOWLY INCREASING UNCERTAINTY
INHERENT IN A SHIFTING, DEAMPLIFYING PATTERN.
8-14 DAY OUTLOOK FOR MAY 27 - JUN 02, 2025
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD DEPICT A SLOWLY PROGRESSIVE AND
DEAMPLIFYING 500-HPA CIRCULATION PATTERN. MEAN 500-HPA ANOMALIES ARE GENERALLY
EXPECTED TO BE SLIGHTLY EAST OF THEIR LOCATION RELATIVE TO THE 6- TO 10-DAY
PERIOD BUT WITH CONSIDERABLY LESSER AMPLITUDE. THESE CHANGES RESULT FROM A SLOW
DEAMPLIFICATION AND INCREASINGLY PROGRESSIVE PATTERN WITH TIME THAT RESOLVES
INTO A RELATIVELY FLAT PATTERN OVER THE WESTERN NORTHERN HEMISPHERE BY THE END
OF WEEK-2. ONE CHANGE FROM LAST WEEK IS THE POTENTIAL FOR THE MID-LEVEL RIDGE
IN THE WEST TO MAINTAIN MORE AMPLITUDE AS IT DRIFTS EASTWARD, BUT THIS HAS
LITTLE EFFECT ON THE SENSIBLE WEATHER. ENSEMBLE MEAN SOLUTIONS PREDICT
MID-LEVEL RIDGING AND SOMEWHAT ABOVE-NORMAL 500-HPA HEIGHTS OVER THE CENTRAL
CONUS WHILE THE WEAK MEAN MID-LEVEL TROUGH AND BELOW-NORMAL 500-HPA HEIGHTS
FARTHER EAST ARE EXPECTED TO FILL, RESULTING IN NEAR-NORMAL HEIGHTS OVER THE
NORTHEAST BY THE END OF WEEK-2. MEANWHILE, THE MID-LEVEL TROUGH OVER AND SOUTH
OF ALASKA MAINTAINS SOME STRENGTH FOR THE FIRST FEW DAYS OF WEEK-2, BUT BY THE
END OF THE PERIOD, IT HAS DRIFTED EAST AND WEAKENED CONSIDERABLY, CONSISTENT
WITH MOST OTHER FEATURES AND THE BROAD-SCALE CHANGES EXPECTED IN THE MID-LEVEL
PATTERN.
ABOVE-NORMAL TEMPERATURES CONTINUE TO BE FAVORED ACROSS MOST OF WESTERN NORTH
AMERICA, PARTS OF THE SOUTHERN PLAINS, AND THE FLORIDA PENINSULA IN THE WEEK-2
PERIOD UNDER RIDGING AND POSITIVE MEAN 500-HPA HEIGHT ANOMALIES. PORTIONS OF
THE PACIFIC NORTHWEST ARE AN EXCEPTION, WITH LOWER HEIGHTS DRIFTING IN FROM THE
NORTHWEST FAVORING NEITHER EXTREME OF TEMPERATURE FOR THE WEEK. PROBABILITIES
OF ABOVE-NORMAL TEMPERATURES NO LONGER REACH 50% ACROSS THE INTERIOR WEST AND
SOUTHERN TEXAS, BUT ODDS FOR WARMTH REMAIN ROBUST IN SOUTHERN FLORIDA, TOPPING
60% OVER THE SOUTHERN HALF OF THE PENINSULA. BELOW-NORMAL TEMPERATURES ARE
AGAIN FAVORED FOR MUCH OF THE EASTERN CONUS UNDER AND TO THE SOUTHWEST OF THE
SLOWLY DEAMPLIFYING TROUGH, CONSISTENT WITH ABOVE-NORMAL SURFACE PRESSURE TO
THE NORTH AND WETTER-THAN-NORMAL CONDITIONS FARTHER SOUTH. BUT INCREASING
500-HPA HEIGHTS OVER THE NORTHERN FRINGE OF THE EASTERN CONUS BRINGS INCREASED
ODDS FOR WARMTH INTO NORTHERN MINNESOTA AND ADJACENT WISCONSIN, AS WELL AS MUCH
OF MAINE. ODDS FOR COOLER-THAN-NORMAL WEATHER EXCEED 50 PERCENT OVER AND NEAR
THE LOWER OHIO VALLEY, THOUGH TEMPERATURES SHOULD SLOWLY TREND CLOSER TO
NEAR-NORMAL WITH TIME. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF
MAINLAND ALASKA UNDER SLOWLY REBOUNDING 500-HPA HEIGHTS TO THE WEST OF THE
WEAKENING TROUGH. ABOVE-NORMAL TEMPERATURES ARE FAVORED TO PERSIST ACROSS
HAWAII DURING WEEK-2 BY DYNAMICAL MODELS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 11, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 35% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5. DECENT
AGREEMENT ON THE MEAN PATTERN IS OFFSET BY AREAS OF DISAGREEMENT IN THE RAW AND
DERIVED TEMPERATURE AND PRECIPITATION TOOLS, PLUS THE UNCERTAINTIES INHERENT TO
A CHANGING, DEAMPLIFYING PATTERN.
FORECASTER: RICH TINKER
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
JUNE 19.
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:
19840429 - 19750519 - 19810514 - 19640508 - 19700429
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:
19640508 - 19840428 - 20040526 - 19750520 - 19700428
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 25 - 29 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A A
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO N A N DAKOTA N A S DAKOTA B A
NEBRASKA B A KANSAS B A OKLAHOMA B A
N TEXAS N A S TEXAS A A W TEXAS N A
MINNESOTA N N IOWA B A MISSOURI B A
ARKANSAS B A LOUISIANA A A WISCONSIN B B
ILLINOIS B A MISSISSIPPI B A MICHIGAN B B
INDIANA B A OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B N
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 27 - JUN 02, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA N N
NEBRASKA N N KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS A A W TEXAS N A
MINNESOTA A B IOWA B N MISSOURI B N
ARKANSAS B A LOUISIANA N A WISCONSIN N B
ILLINOIS B N MISSISSIPPI B A MICHIGAN B N
INDIANA B N OHIO B A KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK N A
VERMONT N A NEW HAMP N A MAINE A A
MASS N A CONN N A RHODE IS N A
PENN B A NEW JERSEY N A W VIRGINIA B A
MARYLAND N A DELAWARE N A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL A A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL B 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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