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FXUS06 KWBC 211912
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED MAY 21 2025
6-10 DAY OUTLOOK FOR MAY 27 - 31 2025
TODAY'S ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT IN DEPICTING A HIGH
AMPLITUDE 500-HPA PATTERN ACROSS MUCH OF NORTH AMERICA. THE PERIOD BEGINS WITH
A POWERFUL TROUGH OVER THE GULF OF ALASKA WITH A SECONDARY TROUGH TO ITS NORTH
NEAR NORTHWESTERN MAINLAND ALASKA. AN ANOMALOUS POSITIVELY TILTED RIDGE IS
FORECAST DOWNSTREAM STRETCHING FROM CENTRAL CANADA TO THE INTERIOR WESTERN
CONTIGUOUS UNITED STATES (CONUS). ANOMALOUS TROUGHING IS FORECAST ACROSS MUCH
OF THE EASTERN CONUS CENTERED NEAR THE GREAT LAKES AND OHIO VALLEY. GENERALLY
NEAR NORMAL HEIGHTS ARE FORECAST FOR HAWAII. AS TIME PROGRESSES, THE PRIMARY
TROUGH OVER THE GULF OF ALASKA IS EXPECTED TO WEAKEN BY DAY 10 AS THE FLOW
PATTERN BECOMES MORE ZONAL. HOWEVER, THE SECONDARY TROUGH NEAR THE NORTHWESTERN
MAINLAND IS FORECAST TO PERSIST. THE RIDGING ACROSS THE WEST IS FORECAST TO
PERSIST THROUGHOUT THE PERIOD WITH ABOVE NORMAL HEIGHTS PREVAILING ACROSS THE
REGION. THE TROUGH OVER THE EASTERN CONUS IS EXPECTED TO SLOWLY WEAKEN AND
PROGRESS TOWARD THE COAST. NEAR NORMAL HEIGHTS ARE GENERALLY FORECAST TO
PERSIST FOR HAWAII WITH TROUGHING INDICATED NORTHWEST OF THE STATE AND RIDGING
FORECAST SOUTHEAST OF THE STATE.
WITH MULTIPLE TROUGHS EXPECTED IN THE VICINITY OF ALASKA, BELOW NORMAL
TEMPERATURES ARE FAVORED FOR MOST OF THE STATE. ABOVE NORMAL TEMPERATURES ARE
LIKELY DOWNSTREAM ACROSS MOST OF THE WESTERN CONUS AND NORTHERN PLAINS.
PROBABILITIES OF ABOVE NORMAL TEMPERATURES EXCEED 80 PERCENT FOR PARTS OF THE
NORTHERN ROCKIES WHERE 5-DAY MEAN TEMPERATURES COULD EXCEED 10 DEGREES ABOVE
NORMAL. BELOW NORMAL TEMPERATURES ARE LIKELY FOR MUCH OF THE SOUTH-CENTRAL AND
SOUTHEASTERN CONUS NORTHWARD TO THE MIDDLE MISSISSIPPI VALLEY AND MID-ATLANTIC
STATES. THE AREA MOST LIKELY TO EXPERIENCE BELOW NORMAL TEMPERATURES EXTENDS
FROM THE TENNESSEE VALLEY WESTWARD TO PARTS OF THE LOWER AND MIDDLE MISSISSIPPI
VALLEY AND ADJACENT AREAS OF THE PLAINS. ABOVE NORMAL TEMPERATURES ARE FAVORED
FOR MUCH OF THE FLORIDA PENINSULA TO THE SOUTH OF THE PREDICTED MEAN FRONTAL
BOUNDARY. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR HAWAII, DUE IN LARGE PART
TO ABOVE NORMAL SEA SURFACE TEMPERATURES (SSTS) IN ADJACENT WATERS.
AN ACTIVE PERIOD IS ANTICIPATED ACROSS ALASKA WITH MULTIPLE TROUGHS AFFECTING
THE STATE. ABOVE NORMAL PRECIPITATION IS FAVORED FOR MOST OF THE STATE
EXTENDING SOUTHWARD TO PARTS OF THE PACIFIC NORTHWEST. THE HIGHEST LIKELIHOOD
OF ABOVE NORMAL PRECIPITATION IS FORECAST FOR SOUTHEAST ALASKA, DUE TO
ANTICIPATED ANOMALOUS ONSHORE FLOW AHEAD OF THE STRONG TROUGH FORECAST OVER THE
GULF OF ALASKA. RIDGING AND SURFACE HIGH PRESSURE IS FORECAST ACROSS MUCH OF
THE WESTERN AND NORTHERN CONUS. AS SUCH, BELOW NORMAL PRECIPITATION IS MOST
LIKELY FROM PARTS OF THE GREAT BASIN TO MOST OF THE NORTH-CENTRAL CONUS.
PROBABILITIES OF SUB-NORMAL PRECIPITATION EXCEED 50 PERCENT ACROSS THE NORTHERN
PLAINS AND UPPER MISSISSIPPI WHERE SURFACE HIGH PRESSURE IS PREDICTED TO
DOMINATE. THIS SURFACE HIGH IS EXPECTED TO PUSH A FRONTAL BOUNDARY FARTHER TO
THE SOUTH THAN TYPICAL THIS TIME OF YEAR, LEADING TO INCREASED PRECIPITATION
CHANCES ACROSS MUCH OF THE SOUTHERN CONUS. THE TAIL END OF THIS FRONTAL
BOUNDARY WILL LIKELY BE A FOCAL POINT FOR INCREASED PRECIPITATION CHANCES FOR
THE SOUTHERN HIGH PLAINS. POTENTIAL MOISTURE ADVECTION FROM BOTH THE GULF AND
FROM POTENTIAL TROPICAL ACTIVITY IN THE PACIFIC ALSO CONTRIBUTE TO INCREASED
TOTALS ACROSS THIS REGION. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED ALONG THE
EASTERN SEABOARD AHEAD OF THE PREDICTED MEAN TROUGH AXIS OVER THE EASTERN CONUS
AND DUE TO POTENTIAL SURFACE LOW DEVELOPMENT NEAR THE MID ATLANTIC EARLY IN THE
PERIOD. A SLIGHT TILT WORD ABOVE NORMAL PRECIPITATION IS INDICATED FOR HAWAII,
CONSISTENT WITH CALIBRATED PRECIPITATION AMOUNTS FROM THE ECMWF AND GEFS
ENSEMBLES.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 20% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
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 AGREEMENT AMONG TODAY’S ENSEMBLE MEANS.
8-14 DAY OUTLOOK FOR MAY 29 - JUN 04, 2025
THE WEEK-2 PERIOD BEGINS WITH A HIGHLY AMPLIFIED PATTERN FEATURING ANOMALOUS
RIDGING ACROSS MUCH OF THE WEST AND NORTHERN PLAINS. TROUGHS ARE PREDICTED OVER
ALASKA AND THE EASTERN SEABOARD. A TROUGH OR CLOSED LOW IS FORECAST OVER THE
EASTERN PACIFIC NEAR THE BAJA CALIFORNIA PENINSULA ASSOCIATED WITH A POTENTIAL
TROPICAL SYSTEM. AS TIME PROGRESSES THE PATTERN BECOMES SIGNIFICANTLY MORE
ZONAL AS THE TROUGH OVER THE GULF OF ALASKA WEAKENS AND THE RESULTANT
DOWNSTREAM FLOW FLATTENS. BY THE END OF WEEK-2, MOST MODEL SOLUTIONS PREDICT
ABOVE NORMAL HEIGHTS OVERSPREADING MOST OF THE CONUS IN THIS LOWER AMPLITUDE
PATTERN. AN EXCEPTION IS FOR PARTS OF MAINLAND ALASKA WHERE RESIDUAL TROUGHING
IS FORECAST TO PERSIST BUT WITH DIMINISHED AMPLITUDE. PERSISTENT TROUGHING IS
ALSO FORECAST OVER THE SOUTHEAST OR GULF COAST WITH MODELS GENERALLY
FORECASTING A SLOW RETROGRESSION OF THIS FEATURE TOWARD THE CENTRAL GULF COAST
BY THE END OF WEEK-2. GENERALLY NEAR NORMAL HEIGHTS ARE EXPECTED FOR HAWAII
THROUGHOUT THE PERIOD.
BELOW NORMAL TEMPERATURES REMAIN LIKELY ACROSS ALASKA DUE TO PREDICTED
TROUGHING, ESPECIALLY EARLY IN THE PERIOD. RIDGING AND ABOVE NORMAL HEIGHTS ARE
FORECAST TO PERSIST ACROSS MOST OF THE WEST AND NORTHERN PLAINS THROUGHOUT THE
PERIOD, LEADING TO INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ACROSS
THESE REGIONS. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE
SOUTHEASTERN AND SOUTH-CENTRAL CONUS, DUE TO ANOMALOUS TROUGHING PREDICTED
EARLY IN THE PERIOD. ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE NORTHEAST
AS HEIGHTS ARE PREDICTED TO RISE ACROSS THE REGION AS TIME PROGRESSES. ABOVE
NORMAL TEMPERATURES ARE FAVORED FOR THE SOUTHERN HALF OF THE FLORIDA PENINSULA
TO THE SOUTH OF A MEAN FRONTAL BOUNDARY. A TILT TOWARD ABOVE NORMAL
TEMPERATURES IS ALSO FORECAST FOR HAWAII DUE TO ABOVE NORMAL SSTS.
AN ACTIVE PATTERN IS ANTICIPATED TO CONTINUE INTO WEEK-2 FOR MUCH OF THE
SOUTHERN TIER OF THE CONUS. A PREDICTED FRONTAL BOUNDARY EARLY IN THE PERIOD
LEADS TO INCREASED CHANCES OF ABOVE NORMAL PRECIPITATION FROM THE SOUTHERN
PLAINS AND SOUTHERN ROCKIES EASTWARD ACROSS THE GULF COAST REGION TO SOUTHERN
PORTIONS OF THE EAST COAST. ABOVE NORMAL PRECIPITATION IS MOST LIKELY FOR PART
OF THE SOUTHERN PLAINS / WESTERN GULF COAST REGION DUE TO POTENTIAL ENHANCED
LOW LEVEL MOISTURE ADVECTION FROM THE GULF. THE TROPICS MAY ALSO BE A PLAYER IN
INCREASING PRECIPITATION CHANCES IN THE SOUTHERN CONUS. THE POTENTIAL
DEVELOPMENT OF A TROPICAL SYSTEM IN THE EASTERN PACIFIC MAY LEAD TO INCREASED
MID-LEVEL MOISTURE ADVECTION TO PORTIONS OF THE SOUTHERN HIGH PLAINS.
ADDITIONALLY, DAILY MODEL OUTPUT IS INDICATING THE POTENTIAL FOR INCREASED
TROPICAL MOISTURE FLOW INTO THE FLORIDA PENINSULA LATER IN WEEK-2. CONVERSELY,
PREDICTED EXPANSIVE SURFACE HIGH PRESSURE FAVORS A DRIER THAN NORMAL PATTERN
ACROSS MOST OF THE NORTHERN CONUS FROM THE GREAT LAKES WESTWARD TO THE NORTHERN
PLAINS. A SLIGHT TILT TOWARD BELOW NORMAL PRECIPITATION ALSO EXTENDS WESTWARD
TO INCLUDE THE NORTHERN ROCKIES, MUCH OF THE COLUMBIA RIVER BASIN, AND PARTS OF
NORTHWESTERN CALIFORNIA DUE TO PREDICTED MID-LEVEL RIDGING. AN ACTIVE PATTERN
REMAINS LIKELY FOR MOST OF ALASKA SOUTHWARD TO EXTREME NORTHERN PORTIONS OF THE
PACIFIC NORTHWEST, DUE TO PREDICTED MEAN CYCLONIC MID-LEVEL FLOW. A SLIGHT TILT
WORD ABOVE NORMAL PRECIPITATION IS INDICATED FOR HAWAII, CONSISTENT WITH
CALIBRATED PRECIPITATION AMOUNTS FROM THE ECMWF AND GEFS ENSEMBLES.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 20% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 50% 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
MODEL AGREEMENT ON AN AMPLIFIED PATTERN EARLY IN THE PERIOD OFFSET BY INCREASED
UNCERTAINTY ASSOCIATED WITH A POTENTIAL CHANGE TO A MORE ZONAL PATTERN LATER IN
THE PERIOD.
FORECASTER: SCOTT H
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:
20040530 - 20010603 - 19990505 - 19620603 - 19890517
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:
20010602 - 20040531 - 19620603 - 19990509 - 19990502
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 27 - 31 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO B A N DAKOTA A B S DAKOTA A B
NEBRASKA B N KANSAS B N OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA B B MISSOURI B N
ARKANSAS B N LOUISIANA B A WISCONSIN A B
ILLINOIS B B MISSISSIPPI B A MICHIGAN N B
INDIANA B B OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B A NEW YORK N A
VERMONT N N NEW HAMP N N MAINE N N
MASS N A CONN N A RHODE IS N A
PENN B A NEW JERSEY N A W VIRGINIA B N
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL N 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
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 29 - JUN 04, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A B E MONTANA A B WYOMING A N
UTAH A A ARIZONA A N COLORADO A A
NEW MEXICO A A N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS N N OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI B N
ARKANSAS B A LOUISIANA B A WISCONSIN A B
ILLINOIS N B MISSISSIPPI B A MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY B B
TENNESSEE B N ALABAMA B A NEW YORK N N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN N B NEW JERSEY N N W VIRGINIA N B
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N N S CAROLINA B N GEORGIA B A
FL PNHDL B A FL PENIN A A AK N SLOPE B N
AK ALEUTIAN B A 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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