315
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 THU MAY 04 2023
6-10 DAY OUTLOOK FOR MAY 10 - 14 2023
THE GFS, ECMWF, AND CANADIAN ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD
AGREEMENT ON THE 6-10 DAY MEAN 500-HPA HEIGHT FORECASTS ACROSS NORTH AMERICA
AND OCEANIC ENVIRONS. A DEEP TROUGH IS ANTICIPATED FROM THE WEST COAST OF
ALASKA SOUTHWARD ACROSS THE ALASKA PENINSULA AND GULF OF ALASKA. THE PREDICTED
DEEPENING OF THIS TROUGH IS ASSOCIATED WITH THE RETROGRESSION OF A MID-LEVEL
RIDGE FROM WESTERN CANADA TO EASTERN AND CENTRAL ALASKA. THE ENSEMBLE MEAN
SOLUTIONS INDICATE THE BROAD CYCLONIC FLOW ON THE SOUTHERN SIDE OF THE GULF OF
ALASKA TROUGH ENDS UP SPLITTING INTO A NORTHERN STREAM AND A SOUTHERN STREAM
NEAR THE WEST COAST OF THE CONTIGUOUS U.S. (CONUS). THE NORTHERN STREAM IS
DIVERTED TOWARDS THE RIDGE OVER WESTERN CANADA AND MUCH OF ALASKA, WHILE THE
SOUTHERN STREAM IS DIVERTED INTO A TROUGH ANTICIPATED OVER THE WESTERN CONUS,
THOUGH THE PLACEMENT OF THIS TROUGH RANGES FROM THE INTERMOUNTAIN REGION TO THE
ROCKIES. THE 6Z DETERMINISTIC GFS RUN PREDICTS THIS TROUGH TO BE MORE AMPLIFIED
AND SITUATED OVER THE ROCKIES AND GREAT PLAINS. FARTHER DOWNSTREAM, A MID-LEVEL
RIDGE IS PREDICTED OVER THE EAST-CENTRAL CONUS, AND ANOTHER DEEP TROUGH IS
FORECAST ACROSS THE CANADIAN MARITIMES AND WESTERN ATLANTIC.
THERE ARE INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR MOST OF THE
PACIFIC NORTHWEST AND NORTHERN INTERMOUNTAIN REGION, AND FROM THE ROCKIES
EASTWARD TO THE ATLANTIC COAST. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES
EXCEED 70% IN THE VICINITY OF THE NORTH-CENTRAL MISSISSIPPI VALLEY. THE
EXCEPTION TO THIS FAVORED ANOMALOUS WARMTH IS THE RIO GRANDE VALLEY OF TEXAS,
WHERE NEAR-NORMAL TEMPERATURES ARE FAVORED. THE EXPANSIVE AREA OF FAVORED
ABOVE-NORMAL TEMPERATURES IS WELL SUPPORTED BY THE TEMPERATURE CONSOLIDATION
FORECAST, THE CALIBRATED REFORECAST TEMPERATURES FROM THE GFS, ECMWF, AND
CANADIAN ENSEMBLE MEANS, AND THE AUTO-TEMPERATURE FORECAST. THIS IS CONSISTENT
WITH THE EXPECTATION OF MID-LEVEL RIDGING AND ABOVE-NORMAL 500-HPA HEIGHTS
ACROSS THIS BROAD REGION. ABOVE-NORMAL TEMPERATURES ARE ALSO INDICATED OVER
NORTHEASTERN PORTIONS OF ALASKA, PRIMARILY SUPPORTED BY THE CONSOLIDATION TOOL
AND ECMWF AND CANADIAN REFORECASTS. NEAR TO SLIGHTLY BELOW-NORMAL 500-HPA
HEIGHTS, AND THE PRESENCE OF A MID-LEVEL TROUGH, FAVOR BELOW-NORMAL
TEMPERATURES FOR PORTIONS OF SOUTHERN CALIFORNIA AND THE SOUTHWEST. THERE ARE
ELEVATED CHANCES FOR BELOW-NORMAL TEMPERATURES FOR SOUTHWESTERN PARTS OF THE
ALASKA COAST, FROM THE ALASKA PENINSULA TO THE SEWARD PENINSULA, IN AN AREA
PREDICTED TO BE DOMINATED BY A 500-HPA TROUGH AND BELOW-NORMAL 500-HPA HEIGHTS.
THERE ARE ELEVATED CHANCES FOR ABOVE-NORMAL PRECIPITATION FOR A LARGE PORTION
OF THE CONUS. THIS INCLUDES FROM THE FOUR CORNER STATES, WYOMING, AND EASTERN
MONTANA EASTWARD ACROSS THE GREAT PLAINS, MOST OF THE MISSISSIPPI VALLEY, THE
LOWER TENNESSEE VALLEY, THE GULF COAST STATES, AND GEORGIA. WESTERN PORTIONS OF
THE AREA OF FAVORED ABOVE-NORMAL PRECIPITATION IS ATTRIBUTED TO THE PROXIMITY
OF A MID-LEVEL TROUGH. FOR CENTRAL AND SOUTHEASTERN PORTIONS OF THE CONUS, A
STORM SYSTEM IS FORECAST TO DEVELOP OVER THE CENTRAL CONUS AND SHIFT EASTWARD
WITH TIME, SUPPLIED WITH AMPLE ATLANTIC AND GULF MOISTURE. WRAP-AROUND, UPSLOPE
PRECIPITATION IS FAVORED OVER THE NORTHERN PLAINS, ON THE NORTHERN SIDE OF THE
STORM SYSTEM. ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED OVER THE VICINITY OF
THE SOUTHERN ALASKA COAST, ASSOCIATED WITH A MID-LEVEL TROUGH AND CYCLONIC
ACTIVITY. ODDS ARE MODESTLY TILTED TOWARDS BELOW-NORMAL PRECIPITATION OVER
MAINE, MOST OF WASHINGTON, OREGON, NORTHERN CALIFORNIA, ADJACENT PARTS OF
NEVADA AND IDAHO, AND THE VICINITY OF ALASKA’S SEWARD PENINSULA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 34% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE-AVERAGE, 4 ON A SCALE OF
1-5. THIS IS DUE TO FAIRLY GOOD AGREEMENT AMONG THE 500-HPA HEIGHT PATTERNS
TODAY, THOUGH OFFSET BY THE UNCERTAINTY IN THE PREDICTED POSITION OF THE
WESTERN CONUS TROUGH.
8-14 DAY OUTLOOK FOR MAY 12 - 18 2023
THE 500-HPA MEAN CIRCULATION PATTERN DURING WEEK-2 IS EXPECTED TO BE SIMILAR TO
THAT PREDICTED DURING THE 6-10 DAY FORECAST PERIOD, THOUGH WITH MINOR
ADJUSTMENTS NEEDED. THE ANTICIPATED SOUTHERN STREAM TROUGH OVER THE WESTERN
CONUS IS DEPICTED OVER CALIFORNIA AND/OR THE SOUTHERN INTERMOUNTAIN REGION BY
THE ENSEMBLE MEANS, WEST OF ITS PREDICTED MEAN POSITION DURING THE 6-10 DAY
PERIOD. ABOVE-AVERAGE 500-HPA HEIGHTS ARE EXPECTED ACROSS MOST OF THE CONUS AND
ALASKA. THE MID-LEVEL FLOW PATTERN ACROSS THE LOWER 48 STATES DURING WEEK-2 IS
PREDICTED TO BE LESS AMPLIFIED RELATIVE TO THE ANTICIPATED FLOW PATTERN DURING
THE 6-10 DAY PERIOD.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MOST OF THE CONUS DURING WEEK-2, DUE
TO PREDICTED ABOVE-AVERAGE MID-TROPOSPHERIC HEIGHTS AND DEAMPLIFIED FLOW. THE
REFORECAST CALIBRATED TEMPERATURE TOOLS, CONSOLIDATED TEMPERATURE TOOL,
BIAS-CORRECTED CANADIAN AND ECMWF ENSEMBLE MEAN TEMPERATURES, AND THE
AUTO-TEMPERATURE FORECAST ARE IN GOOD AGREEMENT WITH THIS PATTERN. INCREASED
PROBABILITIES OF ABOVE-NORMAL TEMPERATURES IN NORTHEASTERN ALASKA, ASSOCIATED
WITH AN AMPLIFYING RIDGE AND RISING HEIGHTS EXPECTED IN THAT AREA, ARE
PREDICTED BY THE REFORECAST AND CONSOLIDATION TEMPERATURE TOOLS. THIS SOLUTION
IS FAVORED OVER THE BELOW-NORMAL TEMPERATURES DEPICTED BY THE BIAS-CORRECTED
ENSEMBLE MEANS, WHICH MAY BE TOO COLD GIVEN THE PREDICTED AMPLIFYING RIDGE AND
RISING HEIGHTS ACROSS THAT AREA. MOST OF THE DYNAMICAL GUIDANCE ALSO SUPPORTS
BELOW-NORMAL TEMPERATURES FOR MUCH OF NEW MEXICO, TEXAS, AND FROM ALASKA’S
SEWARD PENINSULA SOUTHWARD THROUGH THE ALASKA PENINSULA, AND CONTINUING
EASTWARD NEAR THE COAST TO SOUTHEAST ALASKA.
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE ENHANCED FOR APPROXIMATELY THE
SOUTHERN HALF OF THE CONUS, COINCIDENT WITH AND AHEAD OF THE TROUGH FORECAST
OVER CALIFORNIA AND THE SOUTHWEST. THE AUTO-PRECIPITATION AND CONSOLIDATED
PRECIPITATION TOOLS ARE IN GENERAL AGREEMENT WITH THIS FORECAST. ABOVE-NORMAL
PRECIPITATION IS ALSO FAVORED FOR THE SOUTH-CENTRAL COAST OF ALASKA, AND THE
SOUTHEASTERN MAINLAND. THIS IS ASSOCIATED WITH THE PREDICTED PROXIMITY OF A
MID-LEVEL TROUGH. PRECIPITATION ODDS ARE MODESTLY TILTED TOWARDS BELOW-NORMAL
PRECIPITATION FROM THE PACIFIC NORTHWEST EASTWARD ACROSS THE NORTHERN
INTERMOUNTAIN REGION, NORTHERN ROCKIES, AND CONTINUING EASTWARD ACROSS THE
NORTHERN TIER OF STATES TO THE UPPER PENINSULA OF MICHIGAN. THIS REGION IS
EXPECTED TO BE UNDER A MID-LEVEL RIDGE, ABOVE-AVERAGE 500-HPA HEIGHTS, AND IS
WELL REMOVED FROM MEAN STORM TRACK LOCATIONS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 34% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 33% 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 ON A
SCALE OF 1-5, DUE TO FAIR AGREEMENT AMONG THE 500-HPA HEIGHT AND TEMPERATURE
TOOLS, WITH THE MOST UNCERTAINTY REGARDING THE PRECIPITATION OUTLOOK.
FORECASTER: ANTHONY A
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
18.
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:
19710502 - 19830421 - 19560414 - 19800508 - 19980506
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:
19710504 - 19560413 - 19830421 - 19980506 - 19770508
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 10 - 14 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF N N
SRN CALIF B N IDAHO A N NEVADA N N
W MONTANA A N E MONTANA A A WYOMING A A
UTAH N A ARIZONA B A COLORADO A A
NEW MEXICO N A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A N
ILLINOIS A N MISSISSIPPI A A MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
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 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 A N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN N N
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 12 - 18 2023
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 N E MONTANA A N WYOMING A N
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO B A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A A OKLAHOMA A A
N TEXAS N A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA A N MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A N
ILLINOIS A N MISSISSIPPI A A MICHIGAN A N
INDIANA A N OHIO A N 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 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 A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN N N
AK S INT B N AK SO COAST B N AK PNHDL N 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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