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FXUS06 KWBC 271921
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU JULY 27 2023
6-10 DAY OUTLOOK FOR AUG 02 - 06 2023
THERE IS GOOD AGREEMENT ON THE PREDICTED 500-HPA CIRCULATION PATTERN OVER THE
FORECAST DOMAIN FOR THE 6-10 DAY PERIOD AMONG THE GFS, ECMWF AND CANADIAN
ENSEMBLE MEAN MODEL SOLUTIONS. THE MID-LEVEL HEIGHT BLEND DEPICTS POSITIVE
500-HPA HEIGHT ANOMALIES OVER THE ALEUTIANS AND BERING SEA THAT EXTEND ACROSS
ALASKA, AND A MID-LEVEL TROUGH OVER EASTERN SIBERIA. A BROAD MID-LEVEL TROUGH
IS PREDICTED OVER THE GULF OF ALASKA AND EASTERN PACIFIC. A RIDGE AND
ASSOCIATED POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST OVER THE WESTERN,
CENTRAL, AND SOUTHERN CONTIGUOUS U.S. (CONUS). DOWNSTREAM, A TROUGH AND
ASSOCIATED NEGATIVE MID-LEVEL HEIGHT ANOMALIES ARE FORECAST OVER THE
NORTHEASTERN CONUS.
ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS ALASKA IN THE 6-10 DAY PERIOD
UNDER PREDICTED POSITIVE MID-LEVEL HEIGHT ANOMALIES, CONSISTENT WITH DYNAMICAL
MODEL FORECAST TOOLS. ABOVE NORMAL TEMPERATURES ARE ALSO FAVORED ACROSS
SIGNIFICANT PORTIONS OF THE WESTERN, CENTRAL, AND SOUTHERN CONUS, UNDER
POSITIVE 500-HPA HEIGHT ANOMALIES AND IS CONSISTENT WITH REFORECAST- CALIBRATED
AND BIAS-CORRECTED TEMPERATURES FROM THE ECMWF AND GFS ENSEMBLE MEAN MODEL
RUNS. THE GREATEST PROBABILITIES FOR ABOVE NORMAL TEMPERATURES (>80%) ARE
INDICATED OVER THE LOWER MISSISSIPPI VALLEY. NEAR TO BELOW NORMAL TEMPERATURE
PROBABILITIES ARE ENHANCED FROM MUCH OF CALIFORNIA AND NEVADA NORTHEASTWARD
ACROSS THE CENTRAL ROCKIES INTO THE NORTHERN AND CENTRAL HIGH PLAINS. THE
RELATIVELY SMALL AREA OF BELOW NORMAL TEMPERATURES FAVORED FOR PARTS OF THE
CALIFORNIA COAST IS ASSOCIATED WITH THE PROXIMITY OF ANOMALOUSLY COOL OCEAN
SURFACE TEMPERATURES. THE AREA OF FAVORED BELOW NORMAL TEMPERATURES IN THE
VICINITY OF WYOMING MAY BE ASSOCIATED WITH REDUCED MAXIMUM TEMPERATURES DUE TO
INCREASED CLOUD COVER AND PRECIPITATION. BELOW NORMAL TEMPERATURES ARE LIKELY
FOR THE NORTHEAST, EASTERN GREAT LAKES REGION, AND NORTHERN MID-ATLANTIC REGION
UNDER THE PREDICTED TROUGH.
BELOW NORMAL PRECIPITATION IS FAVORED FOR SOUTHERN AND CENTRAL ALASKA UNDER
POSITIVE 500-HPA HEIGHT DEPARTURES. ABOVE NORMAL PRECIPITATION CHANCES ARE
INCREASED OVER NORTHERN ALASKA, AS DEPICTED BY THE CONSOLIDATION PRECIPITATION
TOOL. MOIST LOW PRESSURE SYSTEMS OUT AHEAD OF THE TROUGH OVER THE GULF OF
ALASKA AND EASTERN PACIFIC ENHANCE THE ODDS FOR ABOVE NORMAL PRECIPITATION
ACROSS MUCH OF THE WESTERN AND CENTRAL CONUS. IN ADDITION, MCS ACTIVITY
(THUNDERSTORM CLUSTERS) EAST OF THE RIDGE AXIS OVER THE WESTERN CONUS INCREASES
THE CHANCES OF ABOVE NORMAL PRECIPITATION FOR THE CENTRAL GREAT PLAINS AND
MIDDLE MISSISSIPPI VALLEY. THE AREA OF FAVORED ABOVE NORMAL PRECIPITATION
CONTINUES ACROSS THE GREAT LAKES, OHIO AND TENNESSEE VALLEYS, APPALACHIANS, AND
EAST COAST STATES FROM THE CAROLINAS NORTHEASTWARD TO MAINE, ASSOCIATED WITH
THE MID-LEVEL TROUGH OVER THE EASTERN CONUS. OVER THE SOUTHWEST, BELOW NORMAL
PRECIPITATION CHANCES ARE INCREASED, AS INDICATED BY THE CONSOLIDATION
PRECIPITATION TOOL, AND SIGNIFIES A RELATIVELY WEAK MONSOON. RAW PRECIPITATION
AMOUNTS AND REFORECAST-CALIBRATED PRECIPITATION FROM THE ENSEMBLE MEAN MODEL
SOLUTIONS DEPICT THREE OTHER AREAS OF FAVORED BELOW NORMAL PRECIPITATION. THE
FIRST AREA INCLUDES PORTIONS OF THE GULF COAST REGION (ASSOCIATED WITH THE
SUBTROPICAL RIDGE), AND THE SECOND AREA INCLUDES THE UPPER MISSISSIPPI VALLEY
(SUFFICIENT DISTANCE FROM STORM TRACKS). THE THIRD AREA, WESTERN WASHINGTON, IS
PREDICTED TO BE NEAR THE SOUTHERN LIMIT OF THE DRY SIGNAL ASSOCIATED WITH
POSITIVE 500-HPA HEIGHT ANOMALIES OVER ALASKA AND WESTERN CANADA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 25% 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, BASED
ON GOOD AGREEMENT AMONG THE DYNAMICAL MODEL 500-HPA HEIGHT FORECASTS AND MOST
SURFACE TEMPERATURE TOOLS, OFFSET BY SOME AREAS OF DISAGREEMENT AMONG
PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR AUG 04 - 10 2023
ENSEMBLE MEAN SOLUTIONS FOR THE WEEK-2 500-HPA HEIGHT FORECAST REMAIN IN GOOD
AGREEMENT, AND SHOW GOOD CONTINUITY WITH YESTERDAY’S MODEL RUNS. THE EASTERN
SIBERIA TROUGH IS FORECAST TO PROGRESS TO THE BERING SEA, THOUGH POSITIVE
500-HPA HEIGHT ANOMALIES CONTINUE TO DOMINATE ALASKA. HEIGHT DEPARTURES IN
EXCESS OF +90 METERS ARE ANTICIPATED OVER EASTERN ALASKA AND THE CANADIAN YUKON
AS SHOWN ON THE MANUAL HEIGHT BLEND. MID-LEVEL TROUGHING IS EXPECTED TO PERSIST
OVER THE GULF OF ALASKA AND EASTERN PACIFIC. RELATIVELY SMALL (BUT TYPICAL OF
MID-SUMMER) POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST ACROSS MOST OF THE
CONUS FOR WEEK-2, EXCEPT UNDER A DIGGING TROUGH OVER THE EASTERN CONUS, WHERE
NEAR TO SLIGHTLY ABOVE 500-HPA HEIGHT ANOMALIES ARE INDICATED BY THE MANUAL
HEIGHT BLEND. SIMILAR TO YESTERDAY, THE ENSEMBLE MEAN SOLUTIONS FORECAST A
RETRACTION OF THE EASTERN PORTION OF THE SUBTROPICAL RIDGE OVER THE SOUTHEAST
TOWARDS THE SOUTHWEST CONUS IN WEEK-2. THIS ALLOWS THE EASTERN CONUS TROUGH TO
DIG FARTHER SOUTH, ACROSS MUCH OF THE SOUTHEAST.
BIAS-CORRECTED AND REFORECAST-CALIBRATED TEMPERATURES FAVOR ABOVE NORMAL
TEMPERATURES OVER ALASKA IN THE WEEK-2 PERIOD, UNDER POSITIVE 500-HPA HEIGHTS
ANOMALIES. THE PROJECTED RETRACTION OF THE RIDGE BACK TOWARDS THE SOUTHWESTERN
CONUS FAVORS AN INCREASE IN COVERAGE OF FAVORED ABOVE NORMAL TEMPERATURES OVER
THE WEST, RELATIVE TO THE 6-10 DAY PERIOD. MUCH OF THE SOUTHERN HALF OF THE
CONUS HAS INCREASED CHANCES OF ABOVE NORMAL TEMPERATURES, WITH ODDS IN EXCESS
OF 70% DEPICTED OVER THE FLORIDA PENINSULA. THIS IS CONSISTENT WITH THE
PROXIMITY OF THE SUBTROPICAL RIDGE AND REFORECAST-CALIBRATED TEMPERATURES FROM
THE GFS AND ECMWF ENSEMBLE MEAN MODELS. THERE ARE ELEVATED ODDS OF BELOW NORMAL
TEMPERATURES ACROSS THE GREAT LAKES REGION, OHIO VALLEY, NORTHEAST, AND
NORTHERN MID-ATLANTIC REGION, ASSOCIATED WITH A MID-LEVEL TROUGH, WITH A >50%
CHANCE OF BELOW-NORMAL TEMPERATURES FOR MUCH OF NEW YORK AND NEW ENGLAND. THIS
BROAD REGION OF ELEVATED ODDS FOR BELOW NORMAL TEMPERATURES IS FORECAST TO
EXTEND WESTWARD AND CONNECT WITH THE AREA OF FAVORED BELOW NORMAL TEMPERATURES
OVER PORTIONS OF THE NORTHERN AND CENTRAL PLAINS, AND ADJACENT PARTS OF THE
ROCKIES, AS SUGGESTED BY THE DAILY EVOLUTION OF THE UNCALIBRATED ECMWF ENSEMBLE
MEAN TEMPERATURE GUIDANCE. IN CONTRAST, THE GEFS MAINTAINS AN INTERVENING AREA
OF FAVORED ABOVE NORMAL TEMPERATURES ACROSS THE VICINITY OF THE UPPER
MISSISSIPPI VALLEY AND NORTHERN PLAINS, AND IS THOUGHT TO BE TOO WARM IN THIS
REGION.
WITH INCREASING ENSEMBLE SPREAD AND FAIRLY SMALL 500-HPA HEIGHT ANOMALIES IN
THE MANUAL BLEND OF DYNAMICAL MODEL FORECASTS, THE WEEK-2 PRECIPITATION OUTLOOK
IS SOMEWHAT UNCERTAIN ACROSS MOST OF THE DOMAIN, BUT PERHAPS NOT QUITE AS
UNCERTAIN AS THE PAST FEW DAYS. ABOVE NORMAL PRECIPITATION IS FAVORED ACROSS
WESTERN ALASKA, WHERE DYNAMICAL MODEL RAW PRECIPITATION AMOUNTS AND
REFORECAST-CALIBRATED PRECIPITATION ARE GENERALLY CONSISTENT, IN ADVANCE OF A
MID-LEVEL TROUGH. THERE IS A WEAK TILT IN THE ODDS TOWARDS BELOW NORMAL
PRECIPITATION OVER THE VICINITY OF SOUTHEAST ALASKA AND THE COPPER RIVER BASIN,
UNDER POSITIVE 500-HPA HEIGHT ANOMALIES. FOR THE CONUS, THE WEEK-2
PRECIPITATION OUTLOOK LARGELY RESEMBLES THE 6-10 DAY PRECIPITATION OUTLOOK,
THOUGH WITH SOME NEEDED ADJUSTMENTS. ABOVE NORMAL PRECIPITATION IS FAVORED
AHEAD OF THE EASTERN PACIFIC MID-LEVEL TROUGH FROM MOST OF THE NORTHWESTERN
QUARTER OF THE CONUS (INCLUDING THE NORTHWESTERN HALF OF CALIFORNIA) ACROSS
MUCH OF THE GREAT PLAINS, SOUTH-CENTRAL MISSISSIPPI VALLEY, TENNESSEE VALLEY,
INTERIOR GULF COAST REGION, AND EAST COAST STATES FROM GEORGIA TO MAINE. THERE
IS A NOTICEABLE NORTHWARD SHIFT IN THE FAVORED ABOVE NORMAL PRECIPITATION AREA
ACROSS THE WEST, WHICH IS CONSISTENT WITH THE FORECAST OF RISING MID-LEVEL
HEIGHTS OVER THAT AREA. OVER THE EASTERN HALF OF THE CONUS, THE AREA OF FAVORED
ABOVE NORMAL PRECIPITATION ALIGNS REASONABLY WELL WITH THE EXPECTED LOWERING OF
500-HPA HEIGHTS OVER THE EAST, AND BETTER DEFINES THE SOUTHERN AND EASTERN
FLANKS OF THE EASTERN CONUS TROUGH. AS WAS THE CASE WITH THE EARLIER 6-10 DAY
PERIOD, THE PRECIPITATION OUTLOOK DEPICTS THREE AREAS OF FAVORED BELOW NORMAL
PRECIPITATION OVER THE LOWER 48 STATES. ONE AREA INCLUDES PORTIONS OF THE UPPER
MISSISSIPPI VALLEY AND UPPER GREAT LAKES REGION (SUFFICIENT DISTANCE FROM STORM
TRACKS), WHILE ANOTHER AREA INCLUDES THE WESTERN GULF COAST REGION (ASSOCIATED
WITH THE ANTICIPATED REDUCED PRESENCE OF THE SUBTROPICAL RIDGE IN THE
SOUTHEAST). THE THIRD AREA OF FAVORED BELOW NORMAL PRECIPITATION IS INDICATED
ACROSS MUCH OF THE SOUTHWEST, HIGHLIGHTING THE SLUGGISH START OF THE 2023
MONSOON SEASON.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 33% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 34% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, BASED
ON GOOD AGREEMENT AMONG THE DYNAMICAL MODEL 500-HPA HEIGHT AND SURFACE
TEMPERATURE FORECASTS, OFFSET BY FORECASTS OF WEAK 500-HPA HEIGHT ANOMALIES AND
WEAK SIGNALS IN THE PRECIPITATION TOOLS.
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
AUGUST 17.
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:
19530724 - 19940809 - 19540808 - 19610728 - 19970726
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:
19610727 - 19530723 - 19970725 - 19940809 - 19890709
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 02 - 06 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N A
SRN CALIF N N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING B A
UTAH N A ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA A N S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A A
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN N N
INDIANA A N OHIO N N KENTUCKY A A
TENNESSEE A N ALABAMA A N NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA N A
MARYLAND B A DELAWARE B A VIRGINIA N A
N CAROLINA A A S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A N
AK ALEUTIAN A N AK WESTERN A B AK INT BSN A B
AK S INT A B AK SO COAST A B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 04 - 10 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA N A E MONTANA B A WYOMING B A
UTAH A N ARIZONA A N COLORADO B A
NEW MEXICO A N N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS N A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA B N IOWA B N MISSOURI N N
ARKANSAS A N LOUISIANA A N WISCONSIN B N
ILLINOIS B N MISSISSIPPI A N MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE A N ALABAMA A N NEW YORK B N
VERMONT B N NEW HAMP B N MAINE B N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA N N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A N
AK ALEUTIAN A N AK WESTERN A N AK INT BSN A N
AK S INT A N AK SO COAST A N AK PNHDL A 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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