989
FXUS06 KWBC 151902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON MAY 15 2023
6-10 DAY OUTLOOK FOR MAY 21 - 25 2023
THERE IS DECENT AGREEMENT AMONG THE MODELS WITH RESPECT TO THE 500-HPA HEIGHT
PATTERN ACROSS NORTH AMERICA. HOWEVER, THERE ARE DIFFERENCES WITH RESPECT TO
THE INTENSITY OF THESE FEATURES AND THE RESULTING MID-LEVEL HEIGHT FIELDS
ACROSS EASTERN AND WESTERN PORTIONS OF THE CONTIGUOUS U.S. (CONUS). STRONG
MID-LEVEL RIDGING IS FAVORED OVER THE WESTERN ALEUTIANS, EXTENDING ACROSS MOST
OF ALASKA. A FAVORED SHORT-WAVE TROUGH ACROSS WESTERN CANADA, IN ADDITION TO
MID-LEVEL LOW PRESSURE NEAR THE CALIFORNIA COASTLINE IS FORECAST TO WEAKEN THE
MEAN RIDGE OVER THE WESTERN CONUS. CONVERSELY, THE FORECAST MEAN MID-LEVEL
TROUGH ACROSS THE EASTERN CONUS IS FORECAST TO WEAKEN DURING THE 6-10 DAY
PERIOD, AS THE MEAN MID-LEVEL HIGH PRESSURE IS EXPECTED TO SHIFT EASTWARD
ACROSS THE NORTHERN TIER STATES AND LINK UP WITH A FAVORED STRONG RIDGE OVER
THE NORTH ATLANTIC. BELOW-NORMAL 500-HPA HEIGHTS ARE FAVORED ACROSS MUCH OF THE
SOUTHEASTERN CONUS, ASSOCIATED WITH MID-LEVEL TROUGHING EARLY IN THE 6-10 DAY
PERIOD.
IN ALASKA, BELOW NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF WESTERN
MAINLAND ALASKA, EXTENDING TO THE CENTRAL ALEUTIANS, ASSOCIATED WITH MEAN
NORTHERLY TO NORTHWESTERLY FLOW TO THE NORTHWEST OF A SHORT-WAVE TROUGH.
DOWNSTREAM, ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE INDICATED
ACROSS THE WESTERN AND NORTH-CENTRAL CONUS, UNDERNEATH POSITIVE 500-HPA HEIGHT
ANOMALIES. MID-LEVEL HEIGHTS ARE FORECAST TO RISE ACROSS THE GREAT LAKES AND
NORTHEAST DURING THE NEXT 6 TO 10 DAYS, LEADING TO NEAR TO ABOVE NORMAL
TEMPERATURES ACROSS THOSE REGIONS. BELOW NORMAL TEMPERATURE PROBABILITIES ARE
PREDICTED IN THE SOUTHEASTERN CONUS, ASSOCIATED WITH MEAN SURFACE HIGH PRESSURE
ACROSS THE EASTERN CONUS. RETURN FLOW ALONG ITS SOUTHWESTERN PERIPHERY IS
FAVORED TO PROMOTE INCREASED MOISTURE TRANSPORT INTO THE SOUTH-CENTRAL CONUS,
LEADING TO INCREASED CLOUDINESS AND ENHANCED PROBABILITIES OF BELOW NORMAL
TEMPERATURES ACROSS THE WESTERN GULF COAST STATES AND THE LOWER MISSISSIPPI
VALLEY.
BEHIND A SHORT-WAVE TROUGH OVER THE GULF OF ALASKA, BELOW NORMAL PRECIPITATION
IS FAVORED ACROSS SOUTHWESTERN MAINLAND ALASKA AND THE EASTERN ALEUTIANS.
CONVERSELY, MEAN SOUTHERLY FLOW AHEAD OF THIS FEATURE FAVORS ABOVE NORMAL
PRECIPITATION ACROSS THE EASTERN ALASKA MAINLAND AND THE PANHANDLE. A WEAK TILT
TOWARD BELOW NORMAL PRECIPITATION IS FAVORED ACROSS COASTAL PORTIONS OF THE
PACIFIC NORTHWEST, ASSOCIATED WITH MEAN RIDGING EARLY IN THE 6-10 DAY PERIOD.
BELOW NORMAL PRECIPITATION IS ALSO FAVORED ACROSS MUCH OF THE EASTERN CONUS
FROM THE EASTERN GREAT PLAINS TO THE APPALACHIANS. INCREASED PROBABILITIES OF
ABOVE NORMAL PRECIPITATION ALONG THE COASTAL PLAIN OF THE SOUTHEAST ARE
ASSOCIATED WITH INCREASED STORMINESS ALONG A MEAN FRONTAL BOUNDARY. THERE IS
ALSO THE POTENTIAL FOR THE DEVELOPMENT OF A COASTAL LOW PRESSURE SYSTEM TOWARD
THE START OF THE 6-10 DAY PERIOD. SOUTHEASTERLY FLOW FROM THE GULF OF MEXICO
INCREASES ABOVE NORMAL PRECIPITATION ODDS ACROSS THE SOUTHERN AND CENTRAL HIGH
PLAINS. ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION ACROSS THE FOUR
CORNERS REGION ARE ASSOCIATED WITH MEAN MID-LEVEL LOW PRESSURE NEAR THE
SOUTHERN COAST OF CALIFORNIA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 50% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, AND 50% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT AMONG DYNAMICAL MODELS SOLUTIONS IN THE LOCATION OF THE MAJOR
MID-LEVEL HEIGHT FEATURES ACROSS NORTH AMERICA, OFFSET BY MODEL INCONSISTENCY
WITH RESPECT TO THE INTENSITY OF THESE MAJOR FEATURES AND THE EVOLUTION OF THE
PATTERN.
8-14 DAY OUTLOOK FOR MAY 23 - 29 2023
DYNAMICAL MODELS ARE IN GOOD AGREEMENT IN DEPICTING A GENERAL PROGRESSION OF
THE OVERALL PATTERN ACROSS NORTH AMERICA FROM THE 6-10 DAY PERIOD. STRONG MEAN
500-HPA RIDGING IS FORECAST TO PERSIST INTO THE WEEK-2 PERIOD ACROSS THE
WESTERN ALEUTIANS. DOWNSTREAM, MID-LEVEL TROUGHING IS FORECAST TO INTENSIFY
ACROSS WESTERN NORTH AMERICA. CONVERSELY, 500-HPA RIDGING IS PREDICTED TO
INCREASE ACROSS MUCH OF THE NORTH-CENTRAL AND EASTERN CONUS DURING WEEK-2,
LEADING TO ABOVE NORMAL MID-LEVEL HEIGHTS ACROSS FROM THE NORTHERN PLAINS TO
THE NORTHEAST. ACROSS THE SOUTHEAST AND GULF COAST STATES, A MEAN FRONTAL
BOUNDARY AND THE POTENTIAL FOR STORMINESS FAVORS BELOW NORMAL 500-HPA HEIGHTS.
IN ALASKA, MEAN SURFACE LOW PRESSURE IN THE GULF OF ALASKA FAVORS PREDOMINANTLY
NORTHERLY FLOW AND BELOW NORMAL TEMPERATURES ACROSS MUCH OF WESTERN AND
SOUTHWESTERN ALASKA. POSITIVE 500-HPA HEIGHTS ACROSS MUCH OF THE NORTHERN TIER
OF THE CONUS FAVOR ENHANCED PROBABILITIES OF ABOVE NORMAL TEMPERATURES FROM THE
WEST COAST TO THE NORTHEAST AND MID-ATLANTIC. ACROSS THE SOUTHEAST AND GULF
COAST STATES, EASTERLY FLOW AND INCREASED STORMINESS ALONG A MEAN FRONTAL
BOUNDARY IS PREDICTED TO LEAD TO BELOW NORMAL TEMPERATURES, WITH BELOW NORMAL
TEMPERATURE ODDS EXTENDING INTO NEW MEXICO.
MEAN SURFACE LOW PRESSURE IN THE GULF OF ALASKA FAVORS INCREASED ODDS OF ABOVE
NORMAL PRECIPITATION ACROSS EASTERN INTERIOR AND SOUTHEASTERN MAINLAND ALASKA,
EXTENDING INTO THE PANHANDLE, AND BELOW NORMAL PRECIPITATION ACROSS
SOUTHWESTERN ALASKA. MEAN RIDGING EARLY IN THE WEEK-2 PERIOD FAVORS A TILT IN
THE ODDS TOWARD BELOW NORMAL PRECIPITATION ACROSS PARTS OF THE PACIFIC
NORTHWEST. PREDOMINANT SURFACE HIGH PRESSURE OVER THE EASTERN CONUS INDICATES
AN INCREASED POTENTIAL FOR BELOW NORMAL PRECIPITATION FROM THE MIDDLE
MISSISSIPPI VALLEY TO THE NORTHEAST. FRONTAL ACTIVITY AND THE POTENTIAL FOR THE
DEVELOPMENT OF AN AREA OF LOW PRESSURE ALONG THE SOUTHEAST COAST EARLY IN THE
WEEK-2 PERIOD INCREASES ODDS OF ABOVE NORMAL PRECIPITATION ACROSS THE
SOUTHEAST. MOISTURE TRANSPORT FROM THE GULF OF MEXICO INCREASES ODDS OF ABOVE
NORMAL PRECIPITATION ACROSS PORTIONS OF THE SOUTHERN AND CENTRAL PLAINS.
ENHANCED ODDS OF ABOVE NORMAL PRECIPITATION IN THE FOUR CORNERS IS ASSOCIATED
WITH MID-LEVEL LOW PRESSURE NEAR THE COAST OF SOUTHERN CALIFORNIA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 45% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, AND 55% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT AMONG THE TOOLS IN THE PREDICTED MID-LEVEL HEIGHT PATTERN ACROSS MUCH
OF NORTH AMERICA, BUT WITH SOME INCREASED UNCERTAINTY WITH RESPECT TO THE
EVOLUTION OF THE OVERALL PATTERN AND WITH THE POTENTIAL DEVELOPMENT OF SURFACE
LOW PRESSURE NEAR THE SOUTHEAST COAST.
FORECASTER: ADAM HARTMAN
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:
19570504 - 19720527 - 19860528 - 19870505 - 19890428
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:
19570503 - 19890428 - 19860527 - 19720527 - 19760427
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 21 - 25 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A N E MONTANA A N WYOMING A A
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 N A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI B B
ARKANSAS B B LOUISIANA B B WISCONSIN A B
ILLINOIS N B MISSISSIPPI B B MICHIGAN N B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B NEW YORK N B
VERMONT N N NEW HAMP N N MAINE A N
MASS N N CONN N N RHODE IS N N
PENN N B NEW JERSEY N N W VIRGINIA B B
MARYLAND B B DELAWARE B N VIRGINIA B B
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN A A AK N SLOPE N N
AK ALEUTIAN B B AK WESTERN B N AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 23 - 29 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A N
SRN CALIF A A IDAHO A N NEVADA A A
W MONTANA A N E MONTANA A N WYOMING A A
UTAH A A ARIZONA N A COLORADO A A
NEW MEXICO B A N DAKOTA A N S DAKOTA A N
NEBRASKA A A KANSAS A A OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS N N LOUISIANA B N WISCONSIN A N
ILLINOIS A B MISSISSIPPI B N MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY N B
TENNESSEE N B ALABAMA B N NEW YORK A B
VERMONT A B NEW HAMP A B MAINE A N
MASS A B CONN A B RHODE IS A B
PENN A B NEW JERSEY A B W VIRGINIA N B
MARYLAND A B DELAWARE N B VIRGINIA N B
N CAROLINA N A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N N
AK ALEUTIAN B B AK WESTERN B N AK INT BSN B N
AK S INT B A AK SO COAST B 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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