517
FXUS06 KWBC 191918
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI MAY 19 2023
6-10 DAY OUTLOOK FOR MAY 25 - 29 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 MID-LEVEL TROUGHING OVER THE
BERING SEA 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 AS WELL AS PARTS OF
SOUTHWESTERN CALIFORNIA.
ENHANCED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE FAVORED FROM THE PACIFIC
NORTHWEST AND MOST OF THE INTERIOR WEST, THE NORTH-CENTRAL CONUS, AND 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
NORTHERN AND CENTRAL PLAINS, AND PORTIONS OF THE UPPER MISSISSIPPI VALLEY.
CONVERSELY, A TILT TOWARD BELOW-NORMAL TEMPERATURES IS INDICATED FOR
SOUTHWESTERN CALIFORNIA. ELEVATED PROBABILITIES OF BELOW-NORMAL TEMPERATURES
ARE ALSO FORECAST FOR PORTIONS OF SOUTHERN TEXAS 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
NORTHERN ALASKA, ASSOCIATED WITH A NEARBY MID-LEVEL RIDGE AND ABOVE-AVERAGE
HEIGHTS.
ODDS FOR BELOW-NORMAL PRECIPITATION ARE ALSO FAVORED FROM EASTERN TEXAS
NORTHEASTWARD ACROSS PARTS OF THE LOWER AND MIDDLE MISSISSIPPI VALLEY, THE OHIO
AND TENNESSEE VALLEYS, THE GREAT LAKES REGION INTO THE NORTHEAST. BELOW-NORMAL
PRECIPITATION IS ALSO MOST LIKELY OVER WESTERN WASHINGTON, AND PARTS OF
NORTHERN ARIZONA AND SOUTHERN UTAH. THIS IS CONSISTENT WITH THE PRECIPITATION
CONSOLIDATION TOOL. 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 MUCH OF CALIFORNIA NORTHEASTWARD TO PARTS OF THE NORTHERN
ROCKIES.. 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. ABOVE-NORMAL PRECIPITATION IS LIKELY OVER MUCH 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 27 - JUN 02, 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 NORTHERN 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. CONVERSELY, PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE ELEVATED
ACROSS SOUTHWESTERN CALIFORNIA, SOUTHERN TEXAS 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, WHILE ABOVE-NORMAL
TEMPERATURES ARE LIKELY OVER NORTHERN 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 NEAR- TO ABOVE-NORMAL PRECIPITATION ARE FAVORED
OVER MOST OF THE WESTERN HALF OF THE CONUS, EXCEPT FOR NORTHERN ARIZONA AND
SOUTHERN TEXAS WHERE A TILT TOWARD BELOW-NORMAL PRECIPITATION IS INDICATED).
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 EASTERN 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 MOST OF ALASKA, SUPPORTED BY MOST OF THE
DYNAMICAL PRECIPITATION FORECAST TOOLS.
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
JUNE 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:
19570505 - 19510508 - 19890429 - 20070513 - 19760429
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:
19570505 - 19510508 - 19890430 - 19640529 - 19630518
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 25 - 29 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A A NRN CALIF N A
SRN CALIF B B IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A N ARIZONA A B COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A N
N TEXAS N B S TEXAS N B W TEXAS N A
MINNESOTA A A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A B
ILLINOIS A B MISSISSIPPI N B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE B B ALABAMA B N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A B
MASS N B CONN N B RHODE IS N B
PENN A B NEW JERSEY B B W VIRGINIA N B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST B A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 27 - JUN 02, 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 A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA N N COLORADO A A
NEW MEXICO N A N DAKOTA A N S DAKOTA A N
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS N N S TEXAS N N W TEXAS N A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A 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 N N DELAWARE N N VIRGINIA N A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN N A AK N SLOPE N 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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