883
FXUS06 KWBC 041902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON AUGUST 04 2025
6-10 DAY OUTLOOK FOR AUG 10 - 14 2025
THE ECMWF, GEFS AND CANADIAN ENSEMBLE MODELS BROADLY AGREE ON THE 500-HPA
HEIGHT PATTERN OVER NORTH AMERICA AND SURROUNDING REGIONS DURING THE 6-10 DAY
PERIOD, WITH ONLY MINOR VARIATIONS AMONG THE MODELS IN TERMS OF AMPLITUDE AND
PHASE OF PREDICTED WAVE FEATURES. THE MANUAL HEIGHT BLEND IS BASED ON 0Z
ENSEMBLE MEANS, WEIGHING THE ECMWF MODEL GREATER DUE TO RECENT MODEL ANOMALY
CORRELATION SKILL. THE MANUAL BLEND SHOWS A TROUGH AND BELOW NORMAL 500-HPA
HEIGHTS OVER ALASKA. A STRONG RIDGE AND ABOVE NORMAL 500-HPA HEIGHTS ARE
FORECAST OVER THE NORTHEAST PACIFIC AND THE WESTERN CONTIGUOUS U.S. (CONUS). A
TROUGH IS FORECAST DOWNSTREAM OF THIS RIDGE ACROSS THE NORTH-CENTRAL CONUS.
FARTHER TO THE EAST, STRONG RIDGING IS FORECAST OVER EASTERN CANADA. THIS RIDGE
IS FORECAST TO BE PERSISTENT WITH ABOVE NORMAL HEIGHTS EXPANDING SOUTHWARD TO
THE EASTERN CONUS. NEAR NORMAL 500-HPA HEIGHTS ARE PREDICTED ACROSS HAWAII.
BELOW NORMAL TEMPERATURES ARE FAVORED FOR MOST OF MAINLAND ALASKA DUE TO A
PREDICTED TROUGH AND BELOW NORMAL 500-HPA HEIGHTS OVER THE STATE, WHILE NEAR
NORMAL TEMPERATURES ARE FAVORED OVER PARTS OF SOUTHERN MAINLAND ALASKA AND THE
ALASKA PANHANDLE, SUPPORTED BY TODAY’S CONSOLIDATION TEMPERATURES TOOL. NEAR
NORMAL TEMPERATURE CHANCES ARE ELEVATED OVER THE NORTHERN PLAINS, ASSOCIATED
WITH A PREDICTED MID-LEVEL TROUGH. ABOVE NORMAL TEMPERATURES ARE FAVORED OVER
THE REMAINDER OF THE CONUS. THIS WIDESPREAD AREA OF FAVORED ANOMALOUS WARMTH IS
ATTRIBUTED TO MID-LEVEL RIDGING AND/OR LOW-LEVEL SOUTHERLY FLOW. ABOVE NORMAL
TEMPERATURES ARE LIKELY FOR HAWAII ASSOCIATED WITH ABOVE NORMAL SSTS,
ESPECIALLY FOR WESTERN PORTIONS OF THE ISLAND CHAIN, CONSISTENT WITH THE
AUTOMATED AND CONSOLIDATED TEMPERATURE FORECAST TOOLS.
AN ACTIVE PERIOD IS ANTICIPATED ACROSS MUCH OF ALASKA AS A TROUGH IS FORECAST
TO STRENGTHEN ACROSS THE MAINLAND, CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION OF CALIBRATED MODEL PRECIPITATION FORECASTS. STRONG SUBTROPICAL
RIDGING FAVORS BELOW NORMAL PRECIPITATION ACROSS MUCH OF THE WESTERN CONUS,
EXCEPT FOR PARTS OF NORTHERN IDAHO AND MONTANA, WHERE ABOVE NORMAL
PRECIPITATION IS FAVORED, SUPPORTED BY THE CONSOLIDATED AND AUTOMATED
TEMPERATURE TOOLS. ALSO, NEAR NORMAL OR A SLIGHT LEAN TOWARDS ABOVE-NORMAL
PRECIPITATION IS FORECAST FOR PARTS OF THE DESERT SOUTHWEST WITH INCREASING
MONSOON FLOW LATER IN THIS PERIOD. ABOVE NORMAL PRECIPITATION IS FAVORED OVER
CENTRAL AND EASTERN CONUS, IN AN ENVIRONMENT DOMINATED BY SOUTHERLY RETURN FLOW
FROM THE GULF AND ANY WEAK FRONTAL BOUNDARIES THAT ENHANCE LOW-LEVEL
CONVERGENCE, AND ALSO ASSOCIATED WITH A MID-LEVEL TROUGH THAT IS PREDICTED TO
SLOWLY WEAKEN AS IT MOVES EASTWARD OVER THIS AREA. ABOVE NORMAL PRECIPITATION
IS FAVORED FOR HAWAII, ASSOCIATED WITH A FORECAST WEAKNESS IN TROPICAL RIDGING
ACROSS THE STATE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% 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 AUG 12 - 18 2025
ENSEMBLE MEAN FORECASTS FOR THE 500-HPA CIRCULATION PATTERN OVER NORTH AMERICA
REMAIN IN GENERAL AGREEMENT DURING THE 8-14 DAY PERIOD. IN THE MANUAL BLEND OF
MODEL FORECASTS, A TROUGH AND BELOW NORMAL 500-HPA HEIGHTS ARE FORECAST TO
PERSIST ACROSS ALASKA. ABOVE NORMAL 500-HPA HEIGHTS ARE FORECAST OVER MOST OF
THE CONUS IN THE WEEK-2 PERIOD, BUT EXPECTED TO WEAKEN COMPARED WITH THE 6-10
DAY PERIOD. THE BROAD ANOMALOUS RIDGE FORECAST OVER EASTERN CANADA DURING THE
6-10 DAY PERIOD DEAMPLIFIES. SHALLOW CYCLONIC FLOW IS PREDICTED FARTHER TO THE
NORTH, CENTERED OVER THE GREAT LAKES REGION. SLIGHTLY BELOW NORMAL 500-HPA
HEIGHTS ARE PREDICTED ACROSS HAWAII.
BELOW NORMAL TEMPERATURE CHANCES ARE ELEVATED FOR MOST OF ALASKA, DUE TO A
PERSISTENT TROUGH AND BELOW NORMAL 500-HPA HEIGHTS, AS INDICATED BY TODAY’S
AUTO TEMPERATURE FORECAST. FARTHER SOUTH, MOST OF THE CONUS IS FAVORED TO HAVE
ABOVE NORMAL TEMPERATURES DURING WEEK-2, BASED ON WIDESPREAD MID-LEVEL RIDGING,
POSITIVE 500-HPA HEIGHT DEPARTURES, AND BROAD SOUTHERLY FLOW FROM THE GULF,
SUPPORTED BY MOST OF THE DYNAMICAL TEMPERATURE FORECAST TOOLS. ABOVE NORMAL
TEMPERATURES ARE FAVORED FOR HAWAII, WITH THE HIGHEST CONFIDENCE ACROSS WESTERN
AND CENTRAL PORTIONS OF THE ISLAND CHAIN, CONSISTENT WITH THE CONSOLIDATED AND
AUTOMATED TEMPERATURE TOOLS.
AN ACTIVE PATTERN IS ANTICIPATED TO CONTINUE INTO WEEK-2 FOR MUCH OF ALASKA
ASSOCIATED WITH PERSISTENT TROUGHING. ABOVE NORMAL PRECIPITATION IS ALSO
FAVORED ALONG PORTIONS OF THE NORTHERN TIER OF THE CONUS, UNDERNEATH PREDICTED
SHALLOW CYCLONIC FLOW. ABOVE NORMAL PRECIPITATION CHANCES ARE ALSO ELEVATED FOR
THE MOST OF THE EASTERN CONUS DUE TO ENHANCED MOISTURE ADVECTION ASSOCIATED
WITH PREDICTED SOUTHEASTERLY OR SOUTHERLY LOW-LEVEL FLOW. ABOVE NORMAL
PRECIPITATION IS FAVORED ACROSS PARTS OF SOUTHERN CALIFORNIA AND SOUTHERN
ARIZONA, SUPPORTED BY MOST OF THE DYNAMICAL PRECIPITATION FORECAST TOOLS. NEAR
TO ABOVE NORMAL PRECIPITATION REMAINS FAVORED FOR HAWAII, ASSOCIATED WITH
PREDICTED MID LEVEL TROUGH IN THE VICINITY, WARRANTED BY THE AUTOMATED
PRECIPITATION TOOL.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% 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 THE 500-HPA PATTERN OFFSET BY WEAK PRECIPITATION SIGNALS
ACROSS MUCH OF THE FORECAST DOMAIN.
FORECASTER: LUKE 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
AUGUST 21.
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:
19980801 - 19890716 - 20010816 - 19530818 - 19970728
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:
19980801 - 19890715 - 20010815 - 19970729 - 19970803
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 10 - 14 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B NRN CALIF A N
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA N N E MONTANA N N WYOMING A N
UTAH A B ARIZONA A B COLORADO A N
NEW MEXICO A N N DAKOTA N N S DAKOTA A N
NEBRASKA A N KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A N W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A A NEW JERSEY A N W VIRGINIA A A
MARYLAND A A DELAWARE A 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 B A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 12 - 18 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF N 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 N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A 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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