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FXUS06 KWBC 231902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED APRIL 23 2025
6-10 DAY OUTLOOK FOR APR 29 - MAY 03, 2025
MULTI-MODEL ENSEMBLE MEANS (GEFS, ECENS, AND CMCE) ARE IN GOOD AGREEMENT WITH A
PROGRESSIVE FLOW PATTERN OVER THE CONTIGUOUS U.S. (CONUS) FROM THE END OF APRIL
THROUGH THE BEGINNING OF MAY. A 500-HPA TROUGH IS FORECAST TO SHIFT EASTWARD
FROM THE GREAT PLAINS TO THE EASTERN CONUS, WHILE AN AMPLIFIED MID-LEVEL RIDGE
BECOMES CENTERED ACROSS THE NORTHERN GREAT PLAINS BY DAY 10. FOR THIS 5-DAY
PERIOD, THE MANUAL 500-HPA HEIGHT BLEND DEPICTS POSITIVE 500-HPA HEIGHT
ANOMALIES FOR NEARLY ALL OF THE CONUS STATES WHICH YIELDS AN INCREASED CHANCE
OF ABOVE-NORMAL TEMPERATURES FOR MOST AREAS. ABOVE-NORMAL TEMPERATURE
PROBABILITIES EXCEED 70 PERCENT ACROSS THE MID-ATLANTIC DUE TO ANOMALOUS WARMTH
AHEAD OF A COLD FRONT. ON DAY 7 (APRIL 30TH), THE WARMEST DAY SO FAR THIS YEAR
IS EXPECTED ACROSS THIS REGION WITH MAXIMUM TEMPERATURES AVERAGING 15 TO 20
DEGREES F ABOVE NORMAL. BEHIND A COLD FRONT, COOLER TEMPERATURES ARE FORECAST
TO OVERSPREAD THE EAST COAST ON MAY 2 AND 3. FARTHER TO THE WEST ACROSS THE
NORTHERN HIGH PLAINS AND MUCH OF THE WEST, ABOVE-NORMAL TEMPERATURE
PROBABILITIES ARE ENHANCED ASSOCIATED WITH THE AMPLIFYING 500-HPA RIDGE. NEAR
NORMAL TEMPERATURES ARE LIMITED TO PARTS OF THE SOUTHWEST AND SOUTHERN GREAT
PLAINS DUE TO LOWER 500-HPA HEIGHTS AND FAVORED WETNESS.
ON DAYS 6 AND 7 (APRIL 29 AND 30), A SLOW-MOVING COLD FRONT IS FORECAST TO
ADVANCE EASTWARD FROM THE MIDDLE MISSISSIPPI VALLEY TO THE EAST COAST. BY DAY
10 (MAY 3), THE ECENS IS TRENDING TOWARDS SURFACE LOW DEVELOPMENT ALONG A
STALLED FRONT OVER THE MID-ATLANTIC. THIS SLOW-MOVING COLD FRONT FAVORS
ABOVE-NORMAL PRECIPITATION THROUGHOUT THE EASTERN AND SOUTH-CENTRAL CONUS. THE
TAIL END OF THIS FRONT IS LIKELY TO BECOME STATIONARY AND EXTEND FROM THE TEXAS
GULF COAST NORTHWESTWARD TO THE RIO GRANDE VALLEY AND SOUTHEASTERN NEW MEXICO
WHERE ABOVE-NORMAL PRECIPITATION PROBABILITIES EXCEED 50 PERCENT. IN THE WAKE
OF A COLD FRONT AND WITH A PREDICTED BUILDING 500-HPA RIDGE, A DRIER PATTERN IS
EXPECTED FOR THE NORTHERN GREAT PLAINS. SINCE PRECIPITATION, ASSOCIATED WITH A
LOW PRESSURE SYSTEM, IS FORECAST TO TIME OFF BY DAY 6, A TWO-CATEGORY CHANGE
(ABOVE TO BELOW-NORMAL PRECIPITATION) FROM YESTERDAY WAS NECESSARY FOR THIS
REGION. THE AMPLIFYING RIDGE ALOFT FAVORS NEAR TO BELOW NORMAL PRECIPITATION
FOR MUCH OF THE WEST.
EXCELLENT MODEL AGREEMENT EXISTS OVER ALASKA AND THE NORTH PACIFIC WITH A DEEP
ANOMALOUS 500-HPA TROUGH PREDICTED. THE TROUGH MAGNITUDE IS FORECAST TO PEAK
AROUND DAY 8 WHEN DAILY 500-HPA HEIGHT ANOMALIES RANGE FROM -120 TO -180 METERS
ACROSS SOUTHWESTERN ALASKA. THIS ANOMALOUS TROUGH ALOFT FAVORS
COLDER-THAN-NORMAL TEMPERATURES FOR MUCH OF ALASKA WITH THE LARGEST
BELOW-NORMAL TEMPERATURE PROBABILITIES (GREATER THAN 70 PERCENT) FORECAST FOR
THE NORTH SLOPE. THE ANOMALOUS MID-LEVEL TROUGH ALONG WITH A SURFACE LOW
CENTERED NEAR THE ALASKA PENINSULA SUPPORT AN INCREASED CHANCE OF ABOVE-NORMAL
PRECIPITATION ACROSS A MAJORITY OF ALASKA.
BASED ON THE GEFS AND ECENS, ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL
PRECIPITATION ARE FAVORED FOR HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 35% 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 EVOLVING LONGWAVE PATTERN.
8-14 DAY OUTLOOK FOR MAY 01 - 07 2025
THE GEFS, ECENS, AND CMCE CONTINUE TO INDICATE A PATTERN CHANGE HEADING INTO
THE START OF MAY. THE LONGWAVE 500-HPA TROUGH, THAT HAS BEEN QUITE PERSISTENT
OVER THE WESTERN CONUS DURING APRIL, IS FORECAST TO BE REPLACED BY A RIDGE
EARLY IN WEEK-2. THIS MID-LEVEL RIDGE IS THEN FORECAST TO SLOWLY SHIFT EASTWARD
AND BECOME CENTERED OVER THE GREAT PLAINS BY THE END OF WEEK-2. THE BROAD
500-HPA RIDGE WITH POSITIVE HEIGHT ANOMALIES SUPPORT AN INCREASED CHANCE OF
ABOVE-NORMAL TEMPERATURES THROUGHOUT MUCH OF THE WESTERN AND NORTH-CENTRAL
CONUS. SOUTHERLY SURFACE FLOW AND ANOMALOUS WARMTH EARLY IN WEEK-2 TILT THE
TEMPERATURE OUTLOOK TOWARDS ABOVE-NORMAL TEMPERATURES ALONG THE EAST COAST.
HOWEVER, IN RESPONSE TO THE BUILDING RIDGE UPSTREAM, A 500-HPA TROUGH IS
EXPECTED TO DEVELOP AND BRING A COOLING TREND TO THIS REGION, LATER IN WEEK-2.
BEHIND A COLD FRONT, NEAR NORMAL TEMPERATURES ARE FAVORED FROM THE OHIO VALLEY
SOUTH TO THE LOWER MISSISSIPPI VALLEY. ELEVATED BELOW-NORMAL TEMPERATURE
PROBABILITIES ARE FORECAST FOR MUCH OF TEXAS DUE TO THE EXPECTATION OF
WIDESPREAD CLOUDINESS AND FAVORED WETNESS ALONG A STATIONARY FRONT.
A COLD FRONTAL PASSAGE AT THE BEGINNING OF WEEK-2, AN AMPLIFYING 500-HPA
TROUGH, AND THE POTENTIAL FOR SURFACE LOW DEVELOPMENT FAVOR ABOVE-NORMAL
PRECIPITATION ACROSS THE EASTERN CONUS ALONG WITH THE GULF COAST STATES. DUE TO
A STALLED FRONT EARLY IN WEEK-2 AND THE ENSEMBLE MEANS DEPICTING ONE OR TWO
SHORTWAVE TROUGHS WITHIN THE SOUTHERN STREAM, AN INCREASED CHANCE OF
ABOVE-NORMAL PRECIPITATION IS FORECAST FOR THE SOUTHERN GREAT PLAINS AND FOUR
CORNERS REGION. ALONG AND TO THE EAST OF THE 7-DAY MEAN RIDGE AXIS,
BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS THE NORTHERN GREAT PLAINS AND
UPPER TO MIDDLE MISSISSIPPI VALLEY. A PREDICTED TROUGH ENTERING THE WEST AND
THE POTENTIAL OF A WETTER PATTERN RETURNING BY THE END OF WEEK-2 PRECLUDE GOING
WITH LARGER BELOW-NORMAL PRECIPITATION PROBABILITIES. CONSISTENT WITH THE
AUTOMATED AND CONSOLIDATION TOOLS, ABOVE (BELOW)-NORMAL PRECIPITATION IS
SLIGHTLY FAVORED FOR WASHINGTON, NORTHERN IDAHO, NORTHWESTERN MONTANA (PARTS OF
CALIFORNIA).
THE ANOMALOUS 500-HPA TROUGH IS FORECAST TO PERSIST OVER ALASKA THROUGH THE
BEGINNING OF MAY. THEREFORE, THE 8-14 DAY TEMPERATURE AND PRECIPITATION
OUTLOOKS ARE QUITE SIMILAR TO THE 6-10 DAY PERIOD. A RELATIVELY COOL, WET
PATTERN IS FAVORED FOR MUCH OF ALASKA DURING WEEK-2.
BASED ON THE GEFS AND ECENS, ABOVE-NORMAL TEMPERATURES AND ABOVE-NORMAL
PRECIPITATION ARE FAVORED FOR HAWAII. POSITIVE SEA SURFACE TEMPERATURE
ANOMALIES ALSO SUPPORT ABOVE-NORMAL TEMPERATURES THROUGHOUT HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
MODEL AGREEMENT OFFSET BY UNCERTAINTY ASSOCIATED WITH A FORECAST PATTERN CHANGE
AT THIS TIME OF YEAR.
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 MAY
15.
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:
20020420 - 19540420 - 19810407 - 20080417 - 19640420
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:
20020421 - 19540421 - 20080416 - 19810407 - 20020506
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR APR 29 - MAY 03, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A N
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 A
VERMONT A A NEW HAMP A N MAINE A N
MASS A N CONN A A RHODE IS A N
PENN A A NEW JERSEY A A 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 N
AK ALEUTIAN B A 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 MAY 01 - 07 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A N 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 A COLORADO A A
NEW MEXICO A A N DAKOTA A B S DAKOTA A B
NEBRASKA A N KANSAS A N OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS N N LOUISIANA N A WISCONSIN A B
ILLINOIS N B MISSISSIPPI N A MICHIGAN N B
INDIANA N B OHIO N N KENTUCKY N N
TENNESSEE N N ALABAMA N A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A N
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A 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 N A FL PENIN N A AK N SLOPE B N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B A
AK S INT N A AK SO COAST N A AK PNHDL N 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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