876
FXUS06 KWBC 171906
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON JULY 17 2023
6-10 DAY OUTLOOK FOR JUL 23 - 27 2023
THE 6-10 DAY MEAN 500-HPA HEIGHT PATTERN AS DEPICTED BY TODAY’S WEIGHTED BLEND
OF THE ECMWF, GFS, AND CANADIAN ENSEMBLE MEANS ARE SIMILAR TO YESTERDAY’S
SOLUTIONS ACROSS THE FORECAST DOMAIN. AT 500-HPA AN ELONGATED TROUGH IS
FORECAST FROM THE BERING SEA ACROSS THE GULF OF ALASKA TO THE PACIFIC
NORTHWEST, WITH ANOTHER TROUGH PREDICTED OVER THE EASTERN CONTIGUOUS U.S.
(CONUS). A MID-LEVEL RIDGE IS DEPICTED BETWEEN THESE TWO TROUGHS, CENTERED OVER
THE INTERIOR WEST. THIS RIDGE IS EXPECTED TO BRING WIDESPREAD EXCESSIVE HEAT TO
THE WESTERN CONUS, AND IS IN A FAVORABLE POSITION FOR THE SOUTHWEST TO RECEIVE
AT LEAST SOME MONSOONAL PRECIPITATION. THE 0Z DETERMINISTIC ECMWF AND 6Z GFS
SOLUTIONS ARE GENERALLY IN AGREEMENT WITH THE ENSEMBLE MEAN SOLUTIONS, THOUGH
THE 6Z GFS IS A BIT FASTER AND LESS AMPLIFIED WITH THE EASTERN CONUS TROUGH.
THE MANUAL HEIGHT BLEND DEPICTS POSITIVE 500-HPA HEIGHT ANOMALIES OVER MOST OF
THE CONUS AND ALASKA FOR THE 6-10 DAY PERIOD.
PREDICTED ABOVE NORMAL 500-HPA HEIGHTS OVER MOST OF ALASKA AND THE WESTERN
CONUS FAVOR ABOVE NORMAL TEMPERATURES AT THE SURFACE, AND THIS IS SUPPORTED BY
THE VARIOUS REFORECAST TEMPERATURE TOOLS. AHEAD OF THE EASTERN CONUS TROUGH,
ABOVE NORMAL SURFACE TEMPERATURES ARE ANTICIPATED OVER THE NORTHEAST IN
SOUTH-SOUTHWESTERLY LOW-LEVEL FLOW. ACROSS THE DEEP SOUTH AND FLORIDA, ABOVE
NORMAL TEMPERATURE CHANCES ARE INCREASED THROUGH COMPRESSIONAL HEATING AS A
COOL FRONT APPROACHES FROM THE NORTH. THE GREATER UNCERTAINTY IN THE
TEMPERATURE OUTLOOK IS OVER THE REST OF THE EASTERN CONUS, WHERE A MIX OF NEAR-
AND BELOW NORMAL TEMPERATURES ARE FAVORED. THE BIAS-CORRECTED TEMPERATURES FROM
THE ENSEMBLE MEANS FAVOR GREATER SPATIAL COVERAGE OF BELOW NORMAL TEMPERATURES
OVER THE EAST, AS DO THE REFORECAST TEMPERATURES FROM THE CANADIAN ENSEMBLE
MEAN. HOWEVER, THE REFORECAST TEMPERATURES FROM THE ECMWF AND GFS ENSEMBLE
MEANS, AND THE TWO LATEST CALIBRATED 2-METER TEMPERATURES FROM THE ECMWF
ENSEMBLE MEAN FAVOR NEAR NORMAL TEMPERATURES.
WITH THE MID-LEVEL RIDGE AND INCREASED SUBSIDENCE ALOFT EXPECTED OVER THE
WESTERN CONUS, CHANCES FOR BELOW NORMAL PRECIPITATION ARE INCREASED, THOUGH
WITH TWO EXCEPTIONS. THE FIRST IS THE SOUTHWEST, WHERE MONSOONAL SHOWERS AND
THUNDERSTORMS ARE ANTICIPATED. WITH THE SEASONAL THERMAL LOW PRESSURE IN PLACE,
ANY GULF SURGES THAT OCCUR MAY HELP TO TRANSLATE MEXICAN MOISTURE NORTHWARD
ACROSS THE INTERNATIONAL BORDER INTO FAR SOUTHEASTERN CALIFORNIA OR SOUTHERN
ARIZONA. WITH THE NATIONAL HURRICANE CENTER PREDICTING ONLY A 10% CHANCE OF
TROPICAL CYCLONE FORMATION DURING THE NEXT 7 DAYS IN AN AREA WELL SOUTH OF THE
MOUTH OF THE GULF OF CALIFORNIA, THE ODDS OF GETTING A STRONG GULF SURGE
INITIATED BY A TROPICAL CYCLONE ARE SIGNIFICANTLY REDUCED. THE SECOND EXCEPTION
IS THE PACIFIC NORTHWEST, WHERE A NEARBY MID-LEVEL TROUGH AND ONSHORE FLOW MAY
TRIGGER A FEW SHOWERS OR THUNDERSTORMS. IN THE SOUTHEAST, A NEARBY COOL FRONT
INTERACTING WITH A VERY MOIST AIR MASS IS EXPECTED TO INCREASE THE ODDS OF
ABOVE NORMAL PRECIPITATION. SOME OF THIS PRECIPITATION IS ANTICIPATED TO STREAM
NORTHWARD AHEAD OF THE EASTERN CONUS TROUGH AXIS INTO THE NORTHEAST. FOR
ALASKA, ONSHORE FLOW ELEVATES THE ODDS OF ABOVE NORMAL PRECIPITATION FOR
EASTERN PORTIONS OF THE STATE. RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES
INCREASE THE CHANCES OF BELOW NORMAL PRECIPITATION OVER WESTERN PORTIONS OF
ALASKA.
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 NORMAL, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE VARIOUS MID-LEVEL HEIGHT FORECASTS, OFFSET SOMEWHAT BY
DIFFERENCES IN THE SURFACE TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR JUL 25 - 31 2023
FOR THE WEEK-2 PERIOD, THE PREDICTED MEAN 500-HPA CIRCULATION PATTERN IS
SIMILAR TO THAT EXPECTED DURING THE EARLIER 6-10 DAY PERIOD. MID-LEVEL TROUGHS
ARE INDICATED FROM THE FAR NORTHERN PACIFIC TO THE PACIFIC NORTHWEST, AND OVER
THE EASTERN CONUS, THOUGH WITH SLIGHT EASTWARD PROGRESSION OF THE LATTER
FEATURE COMPARED TO ITS 6-10 DAY FORECAST POSITION. THE MID-LEVEL RIDGE OVER
THE SOUTHWESTERN CONUS IS PREDICTED TO PERSIST THROUGHOUT THE WEEK-2 PERIOD.
THE VARIOUS ENSEMBLE MEAN SOLUTIONS DEPICT POSITIVE 500-HPA HEIGHT ANOMALIES
OVER MOST OF THE CONUS AND ALASKA.
ABOVE NORMAL TEMPERATURE CHANCES ARE INCREASED OVER MOST OF THE LOWER 48 STATES
AND ALASKA DURING THE WEEK-2 FORECAST PERIOD, IN LARGE PART DUE TO THE
PREDOMINANCE OF ANTICIPATED POSITIVE MID-LEVEL HEIGHT ANOMALIES, LARGE-SCALE
RIDGING, AND WEAKENING OF THE EASTERN CONUS TROUGH. REFORECAST TEMPERATURES
FROM THE GFS AND ECMWF ENSEMBLE MEANS, AND TO A LESSER EXTENT THE
BIAS-CORRECTED TEMPERATURES FROM THESE SAME MODELS SUPPORT THE DOMINANCE OF
ABOVE NORMAL TEMPERATURES FAVORED OVER MOST OF THE UNITED STATES. IN CONTRAST,
REFORECAST AND BIAS-CORRECTED TEMPERATURES FROM THE 0Z CANADIAN ENSEMBLE MEAN
DEPICT WIDESPREAD BELOW NORMAL TEMPERATURES OVER MUCH OF THE EAST, CENTERED
NEAR THE TENNESSEE VALLEY AND SOUTHERN APPALACHIANS, RESPECTIVELY. WITH THE
EXPECTED WEAKENING OF THE EASTERN CONUS TROUGH DURING WEEK-2, AND SLIGHTLY
HIGHER GEFS AND ECMWF ENSEMBLE HEIGHT ANOMALY CORRELATION SCORES IN THE PAST
60-DAYS, MORE WEIGHT WAS SUBJECTIVELY GIVEN TOWARDS THESE LATTER MODEL RUNS,
WITH LESS WEIGHT GIVEN TO THE CANADIAN ENSEMBLE MEAN.
THE PRECIPITATION OUTLOOK FOR WEEK-2 IS BASED ON WEAK SIGNALS CHARACTERISTIC OF
THE SUMMER SEASON AND SIGNIFICANT DIFFERENCES BETWEEN THE OBJECTIVE TOOLS.
ABOVE NORMAL PRECIPITATION CHANCES ARE ENHANCED FROM SOUTHERN CALIFORNIA
EASTWARD AND NORTHEASTWARD ACROSS MUCH OF ARIZONA AND THE SOUTH-CENTRAL
ROCKIES, BASED PRIMARILY ON NOMINAL CLASS LIMITS ASSOCIATED WITH THE ARID
CLIMATOLOGY, NOT THE EXPECTATION OF A STRONG MONSOON. A SMALL-SCALE AREA OF
FAVORED ABOVE NORMAL PRECIPITATION IS ALSO DEPICTED OVER PARTS OF THE
NORTHEAST, IN ADVANCE OF A MID-LEVEL TROUGH AXIS, AND WITH STATISTICAL SUPPORT
FROM ANALOGS BASED ON THE MANUAL 500-HPA HEIGHT BLEND. BELOW NORMAL
PRECIPITATION CHANCES ARE ENHANCED OVER PARTS OF THE PACIFIC NORTHWEST, THE
NORTHERN INTERMOUNTAIN REGION, NORTHERN ROCKIES, AND MUCH OF THE GREAT PLAINS
AND MISSISSIPPI VALLEY, ASSOCIATED WITH THE WESTERN MID-LEVEL RIDGE. THE WEAK
PRECIPITATION SIGNALS INDICATED BY A VARIETY OF TOOLS MAKES IT DIFFICULT TO
NARROW DOWN THE MOST LIKELY TRACKS OF SUMMERTIME THUNDERSTORM CLUSTERS (KNOWN
AS MESOSCALE CONVECTIVE SYSTEMS) DOWNSTREAM OF THE WESTERN RIDGE AXIS. IN
ALASKA, THE PRECIPITATION OUTLOOK IS GENERALLY SIMILAR TO THAT OF THE 6-10 DAY
PERIOD, WITH INCREASED CHANCES OF BELOW NORMAL PRECIPITATION OVER
WESTERN/SOUTHWESTERN PORTIONS OF THE STATE, WHILE ABOVE NORMAL PRECIPITATION IS
FAVORED FOR NORTHEASTERN/EASTERN SECTIONS OF ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 25% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR NORMAL, 3 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE VARIOUS MID-LEVEL HEIGHT FORECASTS AND SURFACE
TEMPERATURE TOOLS OFFSET BY LARGE DIFFERENCES IN THE PRECIPITATION MODEL
GUIDANCE.
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
JULY 20.
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:
19940724 - 19930731 - 19960723 - 20060629 - 19840705
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:
20060629 - 19930730 - 19940723 - 19960721 - 20030723
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 23 - 27 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B NRN CALIF A N
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI N N
ARKANSAS N N LOUISIANA A A WISCONSIN A N
ILLINOIS N N MISSISSIPPI N A MICHIGAN A N
INDIANA N N OHIO N N KENTUCKY N N
TENNESSEE N N ALABAMA N A NEW YORK N N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN N A RHODE IS A N
PENN N N NEW JERSEY N A W VIRGINIA N N
MARYLAND N N DELAWARE N A VIRGINIA N N
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN N N AK WESTERN A N AK INT BSN A N
AK S INT A N AK SO COAST N N AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 25 - 31 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 A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
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 A 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 A N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A N
AK ALEUTIAN N N AK WESTERN A N AK INT BSN A N
AK S INT A 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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