696
FXUS06 KWBC 031908
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED MAY 03 2023
6-10 DAY OUTLOOK FOR MAY 09 - 13 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 TROUGH IS ANTICIPATED FROM THE BERING SEA SOUTHEASTWARD
ACROSS THE GULF OF ALASKA TO THE GREAT BASIN OF THE CONTIGUOUS U.S. (CONUS). A
MID-LEVEL RIDGE IS PREDICTED FROM THE EAST-CENTRAL CONUS NORTHWESTWARD ACROSS
THE UPPER MISSISSIPPI VALLEY AND NORTHERN PLAINS, CENTRAL AND WESTERN CANADA,
AND PORTIONS OF EASTERN AND NORTHERN ALASKA. AN AMPLIFIED 500-HPA TROUGH IS
FORECAST FROM THE CANADIAN MARITIMES SOUTHWARD ACROSS THE FAR WESTERN ATLANTIC
OCEAN. WITH TIME, AS THE MID-LEVEL RIDGE SHIFTS WESTWARD, THE MARITIMES TROUGH
IS ALSO EXPECTED TO SHIFT WESTWARD, ALLOWING 500-HPA HEIGHTS TO FALL ACROSS NEW
ENGLAND.
THERE ARE INCREASED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FOR NEARLY ALL
AREAS EAST OF THE CONTINENTAL DIVIDE (THE EXCEPTION BEING NEAR-NORMAL
TEMPERATURES FAVORED FOR PORTIONS OF NEW ENGLAND). THIS 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 MUCH OF THE COUNTRY WEST OF THE CONTINENTAL
DIVIDE. THERE ARE ELEVATED CHANCES FOR BELOW-NORMAL TEMPERATURES FOR THE
SOUTHWESTERN ALASKA MAINLAND AND THE ALASKA 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 THE PACIFIC NORTHWEST AND THE NORTHERN HALF OF
CALIFORNIA EASTWARD ACROSS THE NORTHERN ROCKIES, GREAT PLAINS, MISSISSIPPI
VALLEY, AND FROM THE OHIO VALLEY AND MID-ATLANTIC REGION SOUTHWARD TO THE GULF
AND ATLANTIC COASTS. THE ABOVE-NORMAL PRECIPITATION FAVORED OVER A LARGE
PORTION OF THE WEST IS ASSOCIATED WITH A 500-HPA TROUGH AND RELATED
MID-LATITUDE LOW PRESSURE SYSTEMS. OVER THE CENTRAL AND SOUTHEASTERN CONUS, THE
ANOMALOUS WETNESS IS DUE TO EXPECTED MOIST RETURN FLOW AND FRONTAL ACTIVITY.
ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED OVER THE VICINITY OF THE SOUTHERN
ALASKA COAST, IN PROXIMITY TO A MID-LEVEL TROUGH AND ASSOCIATED CYCLONIC
ACTIVITY. BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ENHANCED OVER PARTS OF
NEW ENGLAND, NORTHWESTERN ALASKA, AND OVER PARTS OF THE CENTRAL AND SOUTHERN
ROCKIES. THIS IS SUPPORTED BY THE PRECIPITATION CONSOLIDATION FORECAST, THE
AUTO-PRECIPITATION FORECAST, AND THE GFS AND ECMWF ENSEMBLE REFORECAST
PRECIPITATION.
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, AND AMONG THE SURFACE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR MAY 11 - 17 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 RIDGE INDICATED FROM THE EAST-CENTRAL CONUS THROUGH
WESTERN AND CENTRAL CANADA TO ALASKA DURING THE 6-10 DAY PERIOD IS FORECAST TO
RETROGRADE APPROXIMATELY 10-15 DEGREES LONGITUDE. THE SOUTHWESTERN PERIPHERY OF
THE MARITIMES TROUGH IS EXPECTED TO LINGER ACROSS NEW ENGLAND. ENSEMBLE MEANS
ALSO INDICATE THE CONTINUATION OF A MEAN TROUGH NEAR THE WEST COAST OF NORTH
AMERICA.
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, AND THE
AUTO-TEMPERATURE FORECAST ARE IN GOOD AGREEMENT WITH THIS PATTERN. INCREASED
PROBABILITIES OF ABOVE-NORMAL TEMPERATURES IN EASTERN AND NORTHERN ALASKA,
ASSOCIATED WITH THE AMPLIFYING RIDGE AND RISING HEIGHTS EXPECTED IN THAT AREA,
ARE PREDICTED BY THE REFORECAST AND CONSOLIDATION TEMPERATURE TOOLS AND IS THE
FAVORED SOLUTION TODAY . HOWEVER, THE AUTO-TEMPERATURE FORECAST AND
BIAS-CORRECTED TOOLS FROM THE VARIOUS ENSEMBLE MEANS FAVOR NEAR TO BELOW-NORMAL
TEMPERATURES FOR THIS AREA. NEAR-NORMAL TEMPERATURES ARE FAVORED FOR REMAINING
AREAS OF THE CONUS AND ALASKA.
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE ENHANCED FOR PARTS OF THE FAR
NORTHERN ROCKIES, THE HIGH PLAINS REGION AND ADJACENT PORTIONS OF THE FOUR
CORNERS REGION AND SOUTHERN PLAINS, THE LOWER MISSISSIPPI VALLEY, AND THE GULF
AND SOUTH ATLANTIC COAST STATES. THE AUTO-PRECIPITATION AND CONSOLIDATED
PRECIPITATION TOOLS ARE IN GENERAL AGREEMENT WITH THIS FORECAST. THIS IS
LARGELY DUE TO THE ANTICIPATED PRESENCE OF A WESTERN CONUS TROUGH AND
DISTURBANCES MOVING SOUTHEASTWARD ACROSS THE NORTHERN INTERMOUNTAIN REGION AND
NORTHERN ROCKIES. THE ANOMALOUS WETNESS FORECAST OVER THE GULF AND SOUTH
ATLANTIC COAST STATES IS ATTRIBUTED TO A MID-LATITUDE STORM SYSTEM PROJECTED TO
MOVE ACROSS THE EASTERN HALF OF THE CONUS DURING WEEK-2. ABOVE-NORMAL
PRECIPITATION IS ALSO FAVORED FOR SOUTH-CENTRAL AND MOST OF SOUTHEAST ALASKA.
THESE AREAS OF FAVORED ABOVE-NORMAL PRECIPITATION ARE SUPPORTED BY THE
AUTO-PRECIPITATION FORECAST AND PRECIPITATION CONSOLIDATION FORECAST, AND ARE
DUE TO THE PROXIMITY OF EXPECTED STORM TRACKS. BELOW-NORMAL PRECIPITATION IS
FAVORED FOR PARTS OF THE UPPER GREAT LAKES REGION, AND FROM NORTHERN CALIFORNIA
EASTWARD THROUGH NORTHERN PORTIONS OF UTAH.
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:
19710504 - 19560413 - 19830421 - 19800508 - 19580507
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:
19560413 - 19710504 - 19830421 - 19980506 - 19730501
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 09 - 13 2023
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 N A E MONTANA A A WYOMING A A
UTAH N N ARIZONA N N COLORADO A N
NEW MEXICO A N 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 A MISSISSIPPI A A MICHIGAN A N
INDIANA A N OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A N
VERMONT N N NEW HAMP N N MAINE N N
MASS N N CONN A N 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 A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN N N
AK S INT N A AK SO COAST N A AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 11 - 17 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 N ARIZONA N A COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A A
N TEXAS N A S TEXAS N A W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA N A WISCONSIN A N
ILLINOIS A N MISSISSIPPI A A 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 A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN A N
AK S INT N N AK SO COAST B 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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