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FXUS06 KWBC 171903
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 17 2023
6-10 DAY OUTLOOK FOR MAY 23 - 27 2023
TODAY'S MODEL SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED AMPLIFIED
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS DURING
THE 6-10 DAY PERIOD. THE MANUAL 500-HPA HEIGHT BLEND IS BASED PRIMARILY ON THE
ENSEMBLE MEANS FROM THE GFS, ECMWF, AND CANADIAN MODEL ENSEMBLES DUE TO RECENT
MODEL SKILL. THE RESULTANT MANUAL BLEND FEATURES ANOMALOUS MID-LEVEL TROUGHING
OVER SOUTHWESTERN ALASKA, AND THE WEST COAST OF THE CONTIGUOUS U.S. (CONUS),
ANOMALOUS RIDGING OVER THE NORTH-CENTRAL AND NORTHEASTERN CONUS, AND A WEAK
TROUGH OVER SOUTHEASTERN CONUS. ABOVE-AVERAGE HEIGHTS ARE FORECAST FOR ALASKA
AND MOST OF THE CONUS DURING THE 6-10 DAY PERIOD, WITH WEAK BELOW-NORMAL
HEIGHTS INDICATED FOR THE GULF COAST REGION AND MUCH OF THE SOUTHEAST.
ENHANCED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM MOST OF THE
WESTERN AND NORTH-CENTRAL CONUS EASTWARD OVER THE GREAT LAKES AND NORTHEAST,
ASSOCIATED WITH MID-LEVEL RIDGING AND/OR ABOVE-AVERAGE 500-HPA HEIGHTS. THE
HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES (IN EXCESS OF 70 PERCENT)
ARE INDICATED OVER PARTS OF THE UPPER AND MIDDLE MISSISSIPPI VALLEY, AND
PORTIONS OF THE NORTHERN? CENTRAL PLAINS. ELEVATED PROBABILITIES OF
BELOW-NORMAL TEMPERATURES ARE FORECAST FOR PORTIONS OF THE SOUTHERN PLAINS AND
MUCH OF THE SOUTHERN ATLANTIC REGION. THIS IS ASSOCIATED WITH INCREASED
PRECIPITATION AND CLOUD COVER ANTICIPATED OVER THESE AREAS, AND ARE SUPPORTED
BY THE BIAS-CORRECTED TEMPERATURE FORECASTS. CHANCES FOR BELOW-NORMAL
TEMPERATURES ARE INCREASED OVER PARTS OF SOUTHWESTERN ALASKA, LARGELY DUE TO
THE PROXIMITY OF A MID-LEVEL TROUGH. PROBABILITIES FOR ABOVE-NORMAL
TEMPERATURES ARE SLIGHTLY ENHANCED OVER PORTIONS OF EASTERN ALASKA, ASSOCIATED
WITH A NEARBY MID-LEVEL RIDGE AND ABOVE-AVERAGE HEIGHTS.
DRIER NORTHERLY FLOW ANTICIPATED OVER WESTERN PORTIONS OF WASHINGTON AND OREGON
FAVORS BELOW-NORMAL PRECIPITATION FOR THE 6-10 DAY PERIOD. ODDS FOR
BELOW-NORMAL PRECIPITATION ARE ALSO FAVORED FROM MUCH OF THE MISSISSIPPI VALLEY
NORTHEASTWARD ACROSS THE CENTRAL AND EASTERN GREAT LAKES REGION, THE OHIO AND
TENNESSEE VALLEYS, AND THE ATLANTIC COAST STATES FROM MAINE SOUTHWESTWARD TO
WEST VIRGINIA. THIS IS CONSISTENT WITH THE PRECIPITATION CONSOLIDATION TOOL AND
CALIBRATED REFORECAST PRECIPITATION. SURFACE LOW PRESSURE DEVELOPMENT OVER
FLORIDA DURING THE FORECAST PERIOD AND ASSOCIATED ONSHORE FLOW INCREASES THE
PROBABILITIES OF ABOVE-NORMAL PRECIPITATION FOR THE SOUTHERN ATLANTIC REGION
AND EASTERN PORTIONS OF THE GULF COAST REGION. RAW PRECIPITATION PROBABILITIES
AND CALIBRATED REFORECAST PRECIPITATION INCREASE THE ODDS OF ABOVE-NORMAL
PRECIPITATION FOR APPROXIMATELY THE SOUTHWESTERN QUARTER OF THE CONUS, WITH
MAXIMUM PROBABILITIES EXCEEDING 50 PERCENT OVER MUCH OF THE FOUR CORNERS
REGION. THIS IS ASSOCIATED WITH INCREASED MOISTURE OUT AHEAD OF THE WEST COAST
TROUGH. A MODEST TILT TOWARDS ABOVE-NORMAL PRECIPITATION IS INDICATED
NORTH-NORTHEASTWARD TO THE CANADIAN BORDER, FROM MONTANA TO THE UPPER
MISSISSIPPI VALLEY. NEAR TO BELOW-NORMAL PRECIPITATION IS FAVORED OVER WESTERN
ALASKA, WHILE ABOVE-NORMAL PRECIPITATION IS LIKELY OVER THE REMAINDER OF THE
STATE OF ALASKA, SUPPORTED BY THE TEMPERATURE CONSOLIDATION AND
AUTO-TEMPERATURE FORECAST TOOLS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 8, 30% 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
FAIRLY GOOD MODEL AGREEMENT REGARDING THE 500-HPA HEIGHT FORECASTS ACROSS NORTH
AMERICA, OFFSET BY DIFFERENCES AMONG THE SURFACE TEMPERATURE AND PRECIPITATION
TOOLS.
8-14 DAY OUTLOOK FOR MAY 25 - 31 2023
ENSEMBLE MEAN SOLUTIONS FOR THE 8-14 DAY PERIOD PREDICT A FAIRLY PERSISTENT
500-HPA CIRCULATION PATTERN ACROSS NORTH AMERICA AND SURROUNDING REGIONS.
ANOMALOUS MID-LEVEL RIDGING WITH ABOVE-NORMAL 500-HPA HEIGHTS IS PREDICTED OVER
THE NORTH-CENTRAL AND NORTHEASTERN CONUS, AND A TROUGH IS EXPECTED TO PERSIST
NEAR THE WEST COAST. A WEAK TROUGH WITH SLIGHTLY BELOW-NORMAL 500-HPA HEIGHTS
IS SITUATED OVER THE SOUTHEAST. MOST ENSEMBLE MEANS AND DETERMINISTIC SOLUTIONS
PREDICT WEAK RIDGING FROM WESTERN CANADA INTO ALASKA.
DURING WEEK-2, INCREASED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE
FORECAST FOR APPROXIMATELY THE NORTHERN TWO-THIRDS OF THE CONUS UNDERNEATH
ANOMALOUS RIDGING. THIS IS WELL SUPPORTED BY THE CALIBRATED REFORECAST
TEMPERATURES, THE TEMPERATURE CONSOLIDATION TOOL, AND THE AUTO-TEMPERATURE
FORECAST. PROBABILITIES OF ABOVE-NORMAL TEMPERATURES EXCEED 60 PERCENT FROM THE
GREAT LAKES REGION EASTWARD ACROSS THE NORTHEAST. CONVERSELY, PROBABILITIES FOR
NEAR- TO BELOW-NORMAL TEMPERATURES ARE ELEVATED ACROSS THE SOUTHERN PLAINS AND
THE SOUTHEAST (EXCEPT FOR SOUTHERN FLORIDA, WHERE ABOVE-NORMAL TEMPERATURES ARE
INDICATED), ASSOCIATED WITH INCREASED PRECIPITATION AND CLOUD COVER. CHANCES
FOR BELOW-NORMAL TEMPERATURES ARE INCREASED OVER SOUTHWESTERN ALASKA, SUPPORTED
BY MOST DYNAMICAL TEMPERATURE FORECAST TOOLS. WITH SNOW COVER DECREASING
SUBSTANTIALLY ACROSS THE STATE, THE BIAS-CORRECTED TEMPERATURE TOOLS MAY BE
ARTIFICIALLY PROLONGING THE DURATION OF ANY PERIOD OF BELOW-NORMAL TEMPERATURES.
INCREASED PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION ARE FAVORED OVER MOST OF
THE WESTERN HALF OF THE CONUS EXTENDING EASTWARD INTO THE UPPER MISSISSIPPI
VALLEY. THIS WIDESPREAD AREA LIES ALONG AND EAST OF A MID-LEVEL TROUGH, WITH
ACCESS TO MOISTURE FROM THE EASTERN PACIFIC OCEAN AND GULF OF MEXICO.
ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED FROM THE CENTRAL GULF COAST REGION
EAST-NORTHEASTWARD TO THE SOUTHERN ATLANTIC COAST, AND IS ASSOCIATED WITH A
SLOW-MOVING LOW PRESSURE SYSTEM. ABOVE-AVERAGE 500-HPA HEIGHTS AND SUFFICIENT
DISTANCE FROM STORM TRACKS FAVOR MODESTLY INCREASED CHANCES FOR BELOW-NORMAL
PRECIPITATION FOR ILLINOIS, THE OHIO VALLEY, AND THE CENTRAL AND EASTERN GREAT
LAKES REGION INTO THE NORTHEAST. ELEVATED CHANCES FOR ABOVE-NORMAL
PRECIPITATION ARE FAVORED OVER EASTERN ALASKA , WHILE BELOW-NORMAL
PRECIPITATION IS SLIGHTLY FAVORED OVER THE WESTERN ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S GFS
SUPERENSEMBLE 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT ON A 500-HPA PATTERN 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 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:
19890428 - 19570505 - 19760428 - 19510507 - 19860529
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:
19890429 - 19570504 - 19760427 - 19510506 - 19850519
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 23 - 27 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A N E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO N A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA N A
N TEXAS N N S TEXAS B N W TEXAS N A
MINNESOTA A A IOWA A N MISSOURI A N
ARKANSAS N N LOUISIANA N N WISCONSIN A N
ILLINOIS A B MISSISSIPPI N N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE N B ALABAMA N N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY N B W VIRGINIA N B
MARYLAND N B DELAWARE N B VIRGINIA N B
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 25 - 31 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF N A
SRN CALIF N A IDAHO A N NEVADA A A
W MONTANA A N E MONTANA A N WYOMING A A
UTAH A A ARIZONA N N COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS N N S TEXAS B N W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA N 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 N N 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 N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN N A AK N SLOPE N N
AK ALEUTIAN B N AK WESTERN N N AK INT BSN N N
AK S INT N N AK SO COAST N 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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