236
FXUS06 KWBC 051902
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 05 2025
6-10 DAY OUTLOOK FOR MAY 11 - 15 2025
TODAY'S GEFS- AND ECMWF- BASED SOLUTIONS ARE IN GOOD AGREEMENT IN DEPICTING A
HIGH AMPLITUDE 500-HPA PATTERN ACROSS MUCH OF NORTH AMERICA. THE CANADIAN
ENSEMBLE MEAN IS AN OUTLIER IN DEPICTING MUCH LESS AMPLIFICATION AND WAS
LARGELY DISCOUNTED TODAY. THE PERIOD BEGINS WITH A POSITIVE NORTH ATLANTIC
OSCILLATION (NAO) CHARACTERIZED BY ANOMALOUS TROUGHING OVER THE DAVIS STRAIT
EXTENDING SOUTHWARD NEAR NORTHERN NEW ENGLAND AND POSITIVE HEIGHT ANOMALIES
ACROSS MUCH OF THE MID-LATITUDE NORTH ATLANTIC. A STRONG ANOMALOUS RIDGE IS
FORECAST ACROSS THE THE NORTHERN PLAINS AND A TROUGH OR CLOSED LOW IS PREDICTED
TO UNDERCUT THIS RIDGE NEAR THE MOUTH OF THE MISSISSIPPI. ACROSS WESTERN NORTH
AMERICA AND THE EASTERN PACIFIC, THREE MAIN FEATURES ARE FORECAST TO DOMINATE,
THE FIRST TWO FEATURES BEING A PAIR OF TROUGHS LOCATED OVER THE BERING SEA AND
JUST OFF THE WEST COAST OF THE CONTIGUOUS UNITED STATES (CONUS). RIDGING IS
FORECAST IN BETWEEN THESE TWO TROUGHS WELL OFFSHORE OF THE PACIFIC NORTHWEST.
AS TIME PROGRESSES, THE PATTERN IS FORECAST TO BE SLOW-MOVING. BY THE END OF
THE PERIOD, THE TROUGH OVER THE BERING SEA IS PREDICTED TO AMPLIFY AND
OVERSPREAD WESTERN ALASKA. THE DOWNSTREAM TROUGH NEAR THE WEST COAST IS
FORECAST TO SLOWLY MOVE ONSHORE AND PROGRESS TO THE INTERIOR WEST BY DAY 10.
THE ANOMALOUS RIDGE OVER THE NORTHERN PLAINS IS FORECAST TO SLOWLY PROGRESS TO
THE GREAT LAKES AND POTENTIALLY THE NORTHEAST TOWARD THE END OF THE PERIOD.
FINALLY, THE TROUGH OR CLOSED LOW NEAR THE MOUTH OF THE MISSISSIPPI IS
PREDICTED TO SLOWLY LIFT NORTHEASTWARD TO THE SOUTHEAST BY THE MIDDLE OF THE
PERIOD AND THEN TO THE SOUTHERN ATLANTIC COAST.
ABOVE NORMAL TEMPERATURES ARE LIKELY FOR MOST OF THE NORTHERN TWO-THIRDS OF THE
CONUS EAST OF THE ROCKIES DUE TO ANOMALOUS AND PERSISTENT RIDGING. THE HIGHEST
LIKELIHOOD OF UNSEASONABLE WARMTH IS ACROSS THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY NEAR THE CENTER OF THE PREDICTED MEAN RIDGE. BELOW NORMAL
TEMPERATURES ARE FAVORED ALONG THE WEST COAST OF THE CONUS AS A TROUGH IS
FORECAST TO MOVE INLAND DURING THE PERIOD. PROBABILITIES OF ABOVE NORMAL
TEMPERATURES ARE ENHANCED ACROSS MUCH OF THE SOUTHWEST, AHEAD OF THE PREDICTED
WEST COAST TROUGH. NEAR TO BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE GULF
COAST REGION AND ADJACENT AREAS OF THE LOWER MISSISSIPPI VALLEY, SOUTHERN
PLAINS, AND SOUTHEAST, AS A SLOW MOVING LOW PROGRESSES FROM THE CENTRAL GULF
COAST TO THE SOUTHEAST. NEAR NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF
WESTERN ALASKA AS THE POSITION OF THE TROUGH TO THE WEST OF THE STATE WOULD
TEND TO LEAD TO ABOVE NORMAL TEMPERATURES WHILE THE BELOW NORMAL HEIGHTS
ASSOCIATED WITH THE TROUGH WOULD ARGUE MORE FOR COLD. NEAR NORMAL TEMPERATURES
WERE FAVORED DUE TO THESE COMPETING INFLUENCES. A SLIGHT TILT TOWARD BELOW
NORMAL TEMPERATURES IS INDICATED FOR EASTERN ALASKA CONSISTENT WITH PREDICTED
NEAR TO BELOW NORMAL 500-HPA HEIGHTS. A SLIGHT TILT TOWARD ABOVE NORMAL
TEMPERATURES IS INDICATED FOR PARTS OF THE ALEUTIANS CONSISTENT WITH THE
MAJORITY OF DYNAMICAL MODEL GUIDANCE. ABOVE NORMAL TEMPERATURES ARE LIKELY
ACROSS HAWAII CONSISTENT WITH ANTICIPATED ABOVE NORMAL SEA SURFACE TEMPERATURES
(SSTS) IN ADJACENT WATERS.
AN ACTIVE PERIOD IS ANTICIPATED ACROSS MUCH OF THE WESTERN CONUS AS AN
ANOMALOUS TROUGH PUSHES INLAND FROM THE PACIFIC DURING THE PERIOD. ABOVE NORMAL
PRECIPITATION IS FAVORED FOR MOST AREAS OF THE CONUS FROM THE ROCKIES WESTWARD
WITH THE EXCEPTION OF CLIMATOLOGICALLY DRY AREAS OF THE SOUTHWEST AND SOUTHERN
CALIFORNIA. AS THE TROUGH PROGRESSES EASTWARD, ABOVE NORMAL PRECIPITATION
PROBABILITIES INCREASE ACROSS PARTS OF THE NORTHERN PLAINS. ABOVE NORMAL
PRECIPITATION IS ALSO LIKELY FOR THE SOUTHEAST AS A SLOW MOVING LOW PRESSURE
SYSTEM IS EXPECTED TO PROMOTE AMPLE MOISTURE ADVECTION INTO THIS REGION FROM
THE GULF. IN BETWEEN THESE TWO ACTIVE REGIONS, PREDICTED EXPANSIVE SURFACE HIGH
PRESSURE IS LIKELY TO LEAD TO BELOW NORMAL PRECIPITATION ACROSS MOST OF THE
SOUTHERN PLAINS, MISSISSIPPI VALLEY, GREAT LAKES, AND NORTHEAST. CONVERSELY,
ABOVE NORMAL PRECIPITATION IS FAVORED ACROSS MUCH OF ALASKA DUE TO PERSISTENT
ANOMALOUS TROUGHING PREDICTED OVER THE BERING SEA. ABOVE NORMAL PRECIPITATION
IS ALSO FAVORED FOR HAWAII, CONSISTENT WITH SKILL WEIGHTED CALIBRATED
PRECIPITATION AMOUNTS CALCULATED FROM THE GEFS AND ECMWF ENSEMBLES.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 20% 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 BETWEEN GEFS- AND ECMWF- BASED SOLUTIONS.
8-14 DAY OUTLOOK FOR MAY 13 - 19 2025
THE WEEK-2 PERIOD BEGINS WITH A HIGHLY AMPLIFIED PATTERN FEATURING ANOMALOUS
RIDGING OVER THE GREAT LAKES AND TROUGHS OVER THE SOUTHEAST, WEST COAST, AND
BERING SEA. AS TIME PROGRESSES THE PATTERN REMAINS PERSISTENT IN MANY AREAS.
THE TROUGH OVER THE BERING SEA IS GENERALLY FORECAST TO REMAIN IN PLACE AND
GRADUALLY REDUCE IN INTENSITY. THE TROUGH NEAR THE WEST COAST IS FORECAST TO
SLOWLY PROGRESS EASTWARD, POTENTIALLY LEADING TO A MORE ACTIVE PATTERN ACROSS
THE PLAINS WITH TIME. THE RIDGE OVER THE GREAT LAKES IS GENERALLY FORECAST TO
REMAIN IN PLACE WHILE THE TROUGH OVER THE SOUTHEAST VERY SLOWLY PROGRESSES
NORTHEASTWARD TOWARD THE MID-ATLANTIC COAST. GENERALLY NEAR NORMAL 500-HPA
HEIGHTS ARE FORECAST FOR HAWAII, WELL TO THE SOUTH OF A RIDGE FORECAST ACROSS
THE EASTERN PACIFIC DURING THE EARLY AND MIDDLE PARTS OF THE PERIOD.
ABOVE NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE CONUS EAST OF THE
ROCKIES. THIS IS ESPECIALLY TRUE FOR THE GREAT LAKES DUE TO PERSISTENT RIDGING.
COOLER THAN NORMAL TEMPERATURES ARE FAVORED WEST OF THE ROCKIES AS A TROUGH
ORIGINALLY NEAR THE WEST COAST SLOWLY PUSHES EASTWARD. NEAR NORMAL TEMPERATURES
ARE FAVORED FOR MOST OF ALASKA DUE TO COMPETING INFLUENCES BETWEEN A RELATIVELY
MILD 500-HPA FLOW PATTERN AND EXPECTED BELOW NORMAL HEIGHTS. BELOW NORMAL
TEMPERATURES REMAIN SLIGHTLY FAVORED FOR SOUTHEASTERN ALASKA CONSISTENT WITH
ANTICIPATED BELOW NORMAL HEIGHTS EARLY IN THE PERIOD. A SLIGHT TILT TOWARD
ABOVE NORMAL TEMPERATURES IS INDICATED FOR PARTS OF THE ALEUTIANS CONSISTENT
WITH THE MAJORITY OF DYNAMICAL MODEL GUIDANCE. ABOVE NORMAL TEMPERATURES REMAIN
LIKELY ACROSS HAWAII ASSOCIATED WITH ANTICIPATED ABOVE NORMAL SSTS IN ADJACENT
WATERS.
AN ACTIVE PATTERN IS ANTICIPATED TO CONTINUE INTO WEEK-2 FOR MUCH OF THE WEST
(WITH THE EXCEPTION OF CLIMATOLOGICALLY DRY AREAS OF THE SOUTHWEST AND SOUTHERN
CALIFORNIA) DUE TO A SLOW MOVING TROUGH. AS THIS TROUGH SLOWLY PROGRESSES
EASTWARD, A MORE ACTIVE PATTERN IS FAVORED FOR MUCH OF THE PLAINS. PREDICTED
ANOMALOUS SOUTHERLY FLOW AHEAD OF THE TROUGH AND LEADS TO AN INCREASE IN
PROBABILITIES OF ABOVE NORMAL PRECIPITATION ACROSS MUCH OF THE PLAINS. THIS IS
PARTICULARLY TRUE FOR THE NORTHERN PLAINS AND PARTS OF THE ROCKIES AS SURFACE
LOW PRESSURE IS FORECAST TO DEVELOP AND POTENTIALLY AMPLIFY PRECIPITATION
AMOUNTS IN THIS REGION. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED FOR PARTS OF
THE SOUTHEAST (PARTICULARLY EARLY IN THE PERIOD) AS A TROUGH SLOWLY EXITS THE
REGION. IN ITS WAKE, SURFACE HIGH PRESSURE FAVORS BELOW NORMAL PRECIPITATION
ACROSS MUCH OF THE REMAINDER OF THE EASTERN CONUS, GENERALLY FROM THE MIDDLE
AND LOWER MISSISSIPPI VALLEY NORTHWARD TO THE NORTHEAST. AN ACTIVE PATTERN AND
INCREASED ABOVE NORMAL PRECIPITATION CHANCES REMAIN FORECAST FOR MUCH OF ALASKA
DUE TO PERSISTENT TROUGHING OVER THE BERING SEA. ABOVE NORMAL PRECIPITATION IS
ALSO FAVORED FOR HAWAII, CONSISTENT WITH SKILL WEIGHTED CALIBRATED
PRECIPITATION AMOUNTS CALCULATED FROM THE GEFS AND ECMWF ENSEMBLES.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 20% 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 PREDICTED FAIRLY PERSISTENT PATTERN.
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 MAY
15.
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 11 - 15 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF N N IDAHO N A NEVADA N A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA N B
N TEXAS N B S TEXAS B B W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS N B LOUISIANA B B WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE N B 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 B
MARYLAND A B DELAWARE A N VIRGINIA A N
N CAROLINA A A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN N A AK N SLOPE N N
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 13 - 19 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA N A WYOMING N A
UTAH B A ARIZONA B N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A B W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B 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 B
MARYLAND A B DELAWARE A B VIRGINIA A N
N CAROLINA A N S CAROLINA A A GEORGIA A N
FL PNHDL A N FL PENIN A A AK N SLOPE N N
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N 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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