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FXUS06 KWBC 181919
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE JULY 18 2023
6-10 DAY OUTLOOK FOR JUL 24 - 28 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, THOUGH WITH A SLIGHT EASTWARD SHIFT OF
THE CIRCULATION FEATURES. 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 NEAR THE EAST COAST OF THE CONTIGUOUS U.S. (CONUS). A
MID-LEVEL RIDGE IS DEPICTED BETWEEN THESE TWO TROUGHS, CENTERED OVER THE
INTERIOR WEST. THE RECENT EXCESSIVE HEAT OVER APPROXIMATELY THE WESTERN HALF OF
THE CONUS IS LARGELY DUE TO THE MAGNITUDE AND PERSISTENCE OF THIS RIDGE. THE 0Z
DETERMINISTIC ECMWF AND 6Z GFS SOLUTIONS ARE GENERALLY IN AGREEMENT WITH THE
ENSEMBLE MEAN SOLUTIONS. 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 MOST OF THE
WESTERN AND CENTRAL CONUS FAVOR ABOVE NORMAL TEMPERATURES AT THE SURFACE, AND
THIS IS SUPPORTED BY THE VARIOUS REFORECAST TEMPERATURE TOOLS. AS THE MID-LEVEL
RIDGE OVER THE WEST BEGINS TO SHIFT EASTWARD, MID-LEVEL HEIGHTS ARE EXPECTED TO
DROP ACROSS THE PACIFIC NORTHWEST FAVORING NEAR TO BELOW NORMAL SURFACE
TEMPERATURES. 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 REDUCED PROBABILITIES FOR ABOVE NORMAL
TEMPERATURES ARE FAVORED. THE BIAS-CORRECTED TEMPERATURES FROM THE ENSEMBLE
MEANS FAVOR REGIONALIZED COVERAGE OF BELOW NORMAL TEMPERATURES OVER THE
SOUTHEAST, AS DOES THE REFORECAST TEMPERATURES FROM THE 0Z CANADIAN ENSEMBLE
MEAN, THOUGH THESE ARE DEEMED TOO COOL OVERALL. NEAR TO BELOW NORMAL
TEMPERATURES ARE FAVORED NEAR THE SOUTHERN COAST OF ALASKA WHERE ANOMALOUSLY
COOL SEA SURFACE TEMPERATURES ARE PRESENT.
WITH THE MID-LEVEL RIDGE AND INCREASED SUBSIDENCE ALOFT EXPECTED OVER THE
WESTERN CONUS, CHANCES FOR BELOW NORMAL PRECIPITATION ARE INCREASED, THOUGH
WITH TWO SMALLER-SCALE 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 20% 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 ASSOCIATED COLD AIR ALOFT MAY TRIGGER A FEW SHOWERS OR THUNDERSTORMS. IN
THE SOUTHEAST AND WESTERN GULF COAST REGION, A WEAKENING BAROCLINIC ZONE
INTERACTING WITH A VERY MOIST AIR MASS AND/OR DIURNAL THUNDERSTORM ACTIVITY
FAVORS NEAR TO ABOVE NORMAL PRECIPITATION. INCREASED CHANCES OF ABOVE NORMAL
PRECIPITATION ARE ALSO ANTICIPATED FOR PORTIONS OF THE GREAT LAKES AND
NORTHEAST, ASSOCIATED WITH A MID-LEVEL TROUGH AND SHORTWAVE DISTURBANCES. 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 SOUTHWESTERN 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 AND SURFACE TEMPERATURE
FORECASTS, OFFSET SOMEWHAT BY DIFFERENCES IN THE PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR JUL 26 - AUG 01, 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 NEAR
THE ATLANTIC SEABOARD. THE MID-LEVEL RIDGE OVER THE SOUTHWESTERN CONUS IS
PREDICTED TO PERSIST THROUGHOUT THE WEEK-2 PERIOD, AND IS SHIFTED SLIGHTLY
EASTWARD OF YESTERDAY’S FORECASTED POSITION FOR WEEK-2. 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 TEMPERATURES FROM THE 0Z CANADIAN ENSEMBLE MEAN DEPICT WIDESPREAD
NEAR TO BELOW NORMAL TEMPERATURES OVER MUCH OF THE EAST, LARGELY CENTERED OVER
THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS. 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. RELATIVE TO TODAY’S 6-10 DAY TEMPERATURE OUTLOOK,
THE WEEK-2 TEMPERATURE OUTLOOK SHOWS AN EASTWARD SHIFT OF THE MAXIMUM
PROBABILITIES FAVORING ABOVE NORMAL TEMPERATURES FROM THE WEST-CENTRAL CONUS
INTO THE CENTRAL CONUS.
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 IN SOUTHERN CALIFORNIA AND
SOUTHERN PARTS OF ARIZONA, BASED PRIMARILY ON LOWER TERCILE THRESHOLDS BEING
MORE EASILY EXCEEDED IN THE SOUTHWEST, NOT THE EXPECTATION OF A STRONG MONSOON.
ODDS FAVOR ABOVE NORMAL PRECIPITATION FROM THE CENTRAL ROCKIES NORTHEASTWARD TO
THE NORTHERN PLAINS, AS DEPICTED BY THE AUTOMATED AND CONSOLIDATED
PRECIPITATION TOOLS. ONE OR MORE DISTURBANCES ROTATING THROUGH THE MID-LEVEL
TROUGH PREDICTED OVER THE GREAT LAKES AND NORTHEAST FAVORS ABOVE NORMAL
PRECIPITATION FOR PORTIONS OF THAT AREA. BELOW NORMAL PRECIPITATION CHANCES ARE
ENHANCED OVER PARTS OF THE PACIFIC NORTHWEST, NORTHERN INTERMOUNTAIN REGION,
NORTHERN ROCKIES, NORTHEASTERN PARTS OF CALIFORNIA, NORTHWESTERN NEVADA, AND
THE SOUTH-CENTRAL GREAT PLAINS AND LOWER MISSISSIPPI VALLEY, AS DEPICTED BY THE
AUTOMATED AND CONSOLIDATED PRECIPITATION TOOLS. 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. OVER THE CENTRAL AND
EASTERN GULF COAST REGION (BUT ESPECIALLY FLORIDA), SOME TOOLS PREDICT BELOW
NORMAL PRECIPITATION, THOUGH THIS SEEMS RATHER UNLIKELY, GIVEN THE MOIST RETURN
FLOW EXPECTED OVER THIS REGION ASSOCIATED WITH THE BERMUDA HIGH. IF THE 500-HPA
SUBTROPICAL RIDGE AXIS SETS UP NORTH OF THE FLORIDA PENINSULA, THE RESULT WOULD
BE DEEP, EASTERLY FLOW AND SLIGHTLY LOWER HEIGHTS ENHANCING DAILY THUNDERSTORM
ACTIVITY. IN ADDITION, ANY LOW-LEVEL CONVERGENCE ZONES (SUCH AS SEA BREEZES)
COULD RESULT IN THE CONDENSATION OF EXCESSIVE UPSTREAM MOISTURE FLOWING ACROSS
ANOMALOUSLY WARM SEA SURFACE TEMPERATURES (EVEN FOR FLORIDA). STATISTICAL
ANALOGS FROM THE MANUAL 500-HPA HEIGHT BLEND ALSO CAUTION AGAINST FORECASTING
BELOW NORMAL PRECIPITATION. THEREFORE, NEAR NORMAL PRECIPITATION IS DEEMED MOST
LIKELY FOR THE CENTRAL AND EASTERN GULF COAST REGION, INCLUDING FLORIDA. IN
ALASKA, THE PRECIPITATION OUTLOOK IS GENERALLY SIMILAR TO THAT OF THE 6-10 DAY
PERIOD, THOUGH WITH INCREASED SPATIAL COVERAGE OF FAVORED ABOVE NORMAL
PRECIPITATION OVER THE MAINLAND AND SOUTHEAST 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:
19930731 - 19940724 - 19960723 - 19840705 - 20030722
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:
19930731 - 19960721 - 20030723 - 19940723 - 20060629
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 24 - 28 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON A B NRN CALIF A B
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 B N DAKOTA A N S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A B ALABAMA A N NEW YORK A N
VERMONT A A NEW HAMP A A MAINE A A
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
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 26 - AUG 01, 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 A
AK ALEUTIAN N N AK WESTERN N N AK INT BSN A A
AK S INT N N AK SO COAST N N 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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