059
FXUS06 KWBC 151901
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI AUGUST 15 2025
6-10 DAY OUTLOOK FOR AUG 21 - 25 2025
THE GEFS, ECENS, AND CMCE REMAIN CONSISTENT AND IN GOOD AGREEMENT THAT AN
UNUSUALLY STRONG MID-LEVEL RIDGE FOR THIS TIME OF YEAR EXPANDS WESTWARD OVER
THE HIGHEST LATITUDES OF THE NORTH ATLANTIC EARLY NEXT WEEK. THE 6-10 DAY
MANUAL BLEND DEPICTS POSITIVE 500-HPA HEIGHT ANOMALIES OF 150 METERS OVER
GREENLAND. THIS ANOMALOUS RIDGE COUPLED WITH AN AMPLIFIED RIDGE CENTERED ACROSS
WESTERN NORTH AMERICA IS FORECAST TO RESULT IN A DEEPENING 500-HPA TROUGH OVER
SOUTHEASTERN CANADA AND THE NORTHEAST. THE MOST LIKELY AREA TO AVERAGE
BELOW-NORMAL TEMPERATURE DURING THIS 5-DAY PERIOD, ALBEIT WITH LIMITED
PROBABILITIES, WOULD BE FROM NEW ENGLAND SOUTHWARD TO THE MID-ATLANTIC. A
VARIABLE TEMPERATURE PATTERN DECREASES FORECAST CONFIDENCE ACROSS THE GREAT
LAKES AND OHIO VALLEY WHERE NEAR NORMAL TEMPERATURES ARE FORECAST. ABOVE-NORMAL
TEMPERATURE PROBABILITIES INCREASE FROM NORTH-TO-SOUTH ACROSS THE SOUTHEAST AS
ANY COLD AIR ADVECTION IS LIKELY TO DIMINISH FARTHER TO THE SOUTH. FOR THE
WESTERN HALF OF THE CONUS, ABOVE-NORMAL TEMPERATURES ARE LIKELY DUE TO THE
AMPLIFIED RIDGE OVER THE WEST. ABOVE-NORMAL TEMPERATURE PROBABILITIES EXCEED 70
PERCENT ACROSS THE GREAT BASIN WHERE THE MULTI-MODEL ENSEMBLE MEAN SOLUTIONS
HAVE 5-DAY TEMPERATURES AVERAGING NEAR OR MORE THAN 10 DEGREES F ABOVE NORMAL.
AS OF 11 AM AST ON AUGUST 15, HURRICANE ERIN IS LOCATED CLOSE TO 500 MILES EAST
OF THE NORTHERN LEEWARD ISLANDS. ALTHOUGH ERIN IS EXPECTED TO TURN NORTHWARD
EARLY NEXT WEEK DUE TO A WEAKNESS IN THE SUBTROPICAL RIDGE, THE WEST-TO-EAST
MODEL SPREAD ON ITS EXACT TRACK BECOMES LARGE. PLEASE REFER TO THE NHC
(WWW.NHC.NOAA.GOV) FOR THE LATEST FORECAST DETAILS. AT THIS TIME, THE MODEL
CONSENSUS IS FOR THE DEEP 500-HPA TROUGH OVER THE CANADIAN MARITIMES TO
EVENTUALLY STEER ERIN NORTHEAST AND AWAY FROM THE EAST COAST LATER NEXT WEEK.
ONE OR TWO COLD FRONTAL PASSAGES FAVOR NEAR TO ABOVE-NORMAL PRECIPITATION
ACROSS THE NORTHEAST AND MID-ATLANTIC, WHILE THE TILT TOWARDS ABOVE NORMAL
ACROSS THE SOUTHEAST AND GULF COAST STATES IS RELATED TO A WEAKER-THAN-NORMAL
SUBTROPICAL RIDGE FOSTERING DIURNAL CONVECTION. ALSO, A TROPICAL WAVE MAY REACH
FLORIDA BY DAY 10. PREVAILING SURFACE HIGH PRESSURE AND NORTHWEST FLOW ELEVATE
THE CHANCE OF BELOW-NORMAL PRECIPITATION ACROSS PARTS OF THE OHIO AND MIDDLE
MISSISSIPPI VALLEYS. A 500-HPA RIDGE AXIS IS FORECAST TO BE CENTERED ACROSS THE
FOUR CORNERS WHICH IS A FAVORABLE LOCATION FOR AN ENHANCED MONSOON. INITIALLY,
THE MID-LEVEL RIDGE SHOULD BE STRONG ENOUGH TO LIMIT CONVECTION BUT AS 500-HPA
HEIGHTS DECREASE, CONVECTIVE RAINFALL IS EXPECTED TO INCREASE LATER IN THIS
PERIOD. THEREFORE, ABOVE-NORMAL PRECIPITATION IS FAVORED FROM THE SOUTHWEST
NORTHWARD TO THE GREAT BASIN AND CENTRAL ROCKIES. NORTHWEST FLOW ALOFT WITH
EMBEDDED SHORTWAVE TROUGHS ELEVATE ABOVE-NORMAL PRECIPITATION PROBABILITIES
ACROSS THE NORTH-CENTRAL CONUS. ALTHOUGH LATE AUGUST IS A DRIER TIME OF YEAR,
BELOW-NORMAL PRECIPITATION IS STILL THE MOST LIKELY OUTCOME FOR THE PACIFIC
NORTHWEST AND NORTHERN INTERMOUNTAIN WEST WITH BROAD 500-HPA RIDGING OVER
WESTERN NORTH AMERICA.
THE GEFS, ECENS, AND CMCE DEPICT A SOUTHWEST TO NORTHEAST ORIENTED 500-HPA
RIDGE FROM THE ALEUTIANS TO SOUTHERN MAINLAND ALASKA. THIS RIDGE FAVORS NEAR TO
ABOVE-NORMAL TEMPERATURES STATEWIDE WITH BELOW-NORMAL PRECIPITATION FAVORED FOR
PARTS OF SOUTHEASTERN ALASKA. FORECAST CONFIDENCE IS RELATIVELY HIGH FOR
ABOVE-NORMAL PRECIPITATION ACROSS NORTHWESTERN ALASKA DUE TO ENHANCED ONSHORE
FLOW AND GOOD MODEL AGREEMENT.
BASED ON THE GEFS AND ECENS, ABOVE-NORMAL TEMPERATURES AND NEAR NORMAL
PRECIPITATION ARE FAVORED FOR HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 35% 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 MODEL AGREEMENT AND CONSISTENCY ON THE LONGWAVE PATTERN.
8-14 DAY OUTLOOK FOR AUG 23 - 29 2025
MULTI-MODEL ENSEMBLE MEANS (GEFS, ECENS, AND CMCE) ARE IN GOOD AGREEMENT AT THE
BEGINNING OF WEEK-2 WITH A DEEP 500-HPA TROUGH EXTENDING FROM SOUTHEASTERN
CANADA INTO THE NORTHEASTERN CONUS ALONG WITH AN AMPLIFIED RIDGE OVER WESTERN
NORTH AMERICA. HOWEVER, AS EARLY AS DAY 10 OR 11, THESE ENSEMBLE MEAN SOLUTIONS
DEPICT THE WESTERN RIDGE WEAKENING AS A TROUGH IS FORECAST TO APPROACH THE WEST
COAST. GIVEN THE GOOD MODEL AGREEMENT FOR LOWER 500-HPA HEIGHTS OVER THE WEST
COMPARED TO YESTERDAY, ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE DECREASED.
TEMPERATURE TOOLS ALONG WITH POSITIVE 500-HPA HEIGHT ANOMALIES SUPPORT AN
INCREASED CHANCE OF ABOVE-NORMAL TEMPERATURES ACROSS THE WEST, CENTRAL TO
SOUTHERN GREAT PLAINS, LOWER TO MIDDLE MISSISSIPPI VALLEY, AND SOUTHEAST.
BELOW-NORMAL TEMPERATURES ARE MORE LIKELY FOR THE UPPER MISSISSIPPI VALLEY,
GREAT LAKES, AND NORTHEAST DUE TO THE INFLUENCE FROM A DEEP 500-HPA TROUGH OVER
SOUTHEASTERN CANADA.
ALTHOUGH THE WEEK-2 OUTLOOK TILTS TOWARDS THE WET SIDE ACROSS THE SOUTHWEST,
GREAT BASIN, AND CENTRAL ROCKIES, THE PATTERN IS EXPECTED TO BECOME LESS
FAVORABLE FOR AN ENHANCED MONSOON LATER IN THIS PERIOD AS A 500-HPA TROUGH
APPROACHES THE WEST COAST AND THE FLOW BECOMES MORE WESTERLY. THE UPSTREAM
MID-LEVEL TROUGH SUPPORTS AN ELEVATED CHANCE OF ABOVE-NORMAL PRECIPITATION FROM
THE PACIFIC NORTHWEST EAST TO THE NORTHERN AND CENTRAL GREAT PLAINS. A
TWO-CATEGORY CHANGE (BELOW TO ABOVE-NORMAL PRECIPITATION) FROM THE 6-10 TO 8-14
DAY PERIOD IS NECESSARY DUE TO THE APPROACHING TROUGH BY DAY 11. THE DRY SIGNAL
ACROSS THE CENTRAL CONUS HAS DIMINISHED TODAY IN THE MODEL GUIDANCE AND NEAR
NORMAL PRECIPITATION IS NOW FORECAST FROM THE GREAT LAKES SOUTHWARD TO THE
MIDDLE MISSISSIPPI VALLEY AND OZARKS. FOLLOWING HURRICANE ERIN, A SERIES OF
TROPICAL WAVES ARE EXPECTED TO CROSS THE MAIN DEVELOPMENT REGION OF THE
ATLANTIC. THE DETERMINISTIC 0Z ECMWF AND 12Z GFS MODELS ALONG WITH SEVERAL
ENSEMBLE MEMBERS FROM THE GEFS AND ECENS FAVOR THE NEXT TROPICAL WAVE OR
CYCLONE REACHING THE BAHAMAS OR CUBA EARLY IN WEEK-2. THE WET TILT FORECAST FOR
THE FLORIDA PENINSULA AND THE COASTAL SOUTHEAST IS RELATED TO THE POTENTIAL FOR
ENHANCED RAINFALL WITH THIS TROPICAL WAVE. A MID-LEVEL TROUGH AND CYCLONIC FLOW
SUPPORT AN ELEVATED CHANCE OF ABOVE-NORMAL PRECIPITATION ACROSS THE NORTHEAST.
POSITIVE 500-HPA HEIGHT ANOMALIES FAVOR ABOVE-NORMAL TEMPERATURES ACROSS THE
SOUTHERN TWO-THIRDS OF ALASKA. ENSEMBLE MEAN SOLUTIONS, ESPECIALLY THE ECENS,
HAVE TRENDED TOWARDS LOWER 500-HPA HEIGHTS FOR NORTHERN ALASKA WITH A DEEP,
CLOSED MID-LEVEL LOW NORTH OF THE STATE. THEREFORE, NEAR NORMAL TEMPERATURES
ARE FORECAST ACROSS NORTHERN ALASKA. SIMILAR TO THE 6-10 DAY PERIOD, ENHANCED
ONSHORE FLOW FROM THE BERING SEA LEADS TO AN INCREASED CHANCE OF ABOVE-NORMAL
PRECIPITATION ACROSS NEARLY ALL OF MAINLAND ALASKA.
BASED ON THE GEFS AND ECENS, ABOVE-NORMAL TEMPERATURES AND NEAR TO BELOW-NORMAL
PRECIPITATION ARE FAVORED FOR HAWAII. POSITIVE SEA SURFACE TEMPERATURE
ANOMALIES ALSO SUPPORT ABOVE-NORMAL TEMPERATURES, ESPECIALLY ACROSS THE
NORTHWESTERN ISLANDS.
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: BELOW AVERAGE, 2 OUT OF 5, DUE TO
A QUICK TRANSITION TO A LESS AMPLIFIED LONGWAVE PATTERN AND WEAK SIGNALS AMONG
THE PRECIPITATION TOOLS.
FORECASTER: BRAD PUGH
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:
19960806 - 19980815 - 19590827 - 19530811 - 19810730
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:
19960805 - 19590828 - 19810730 - 20060728 - 19980815
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 21 - 25 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A N
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A N
N TEXAS A N S TEXAS A A W TEXAS A N
MINNESOTA N A IOWA N N MISSOURI A B
ARKANSAS A B LOUISIANA A A WISCONSIN N N
ILLINOIS N B MISSISSIPPI A N MICHIGAN N N
INDIANA N B OHIO N B KENTUCKY N N
TENNESSEE N N ALABAMA A A NEW YORK B N
VERMONT B N NEW HAMP B N MAINE B A
MASS B N CONN B N RHODE IS B N
PENN N N NEW JERSEY B N W VIRGINIA N N
MARYLAND B N DELAWARE B N VIRGINIA B 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 A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 23 - 29 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA N A S DAKOTA N A
NEBRASKA A A KANSAS A A OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA B N IOWA N N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN B N
ILLINOIS A N MISSISSIPPI A N MICHIGAN B N
INDIANA N N OHIO B N KENTUCKY A N
TENNESSEE A N ALABAMA A N NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B N NEW JERSEY B A W VIRGINIA B N
MARYLAND B N DELAWARE B A VIRGINIA N N
N CAROLINA A A S CAROLINA A A GEORGIA A N
FL PNHDL A N FL PENIN A A AK N SLOPE N A
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A N 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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