882
FXUS06 KWBC 281907
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI JULY 28 2023
6-10 DAY OUTLOOK FOR AUG 03 - 07 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 EASTERN BERING SEA THAT EXTEND ACROSS ALASKA,
AND A MID-LEVEL TROUGH CENTERED OVER THE KAMCHATKA PENINSULA IN FAR EASTERN
RUSSIA. 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. SHORTWAVE TROUGHS DIGGING SOUTHWARD ON
THE WESTERN FLANK OF THE LONGWAVE TROUGH HELP TO MAINTAIN MEAN TROUGHING AND
CYCLONIC CURVATURE ACROSS THIS REGION.
ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS ALASKA 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 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. THE
RELATIVELY SMALL AREA OF NEAR 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 OVER THE
NORTHERN AND CENTRAL PLAINS AND THE CENTRAL ROCKIES MAY BE DUE TO A COMBINATION
OF RECENT TEMPERATURE CALIBRATION AND A FORECASTED REDUCTION IN MAXIMUM
TEMPERATURES DUE TO INCREASED CLOUD COVER AND PRECIPITATION. BELOW NORMAL
TEMPERATURES ARE LIKELY FOR THE GREAT LAKES, NORTHEAST, AND NORTHERN
MID-ATLANTIC REGION UNDER THE PREDICTED TROUGH.
TODAY’S 6-10 DAY PRECIPITATION OUTLOOK IS GENERALLY SIMILAR TO YESTERDAY’S
PRECIPITATION OUTLOOK, BUT IS HINDERED BY WEAK AND CONFLICTING OBJECTIVE
GUIDANCE IN SOME AREAS. LARGER-SCALE AND BETTER DEFINED PRECIPITATION SIGNALS
INCLUDE A TILT IN THE ODDS TOWARDS ABOVE NORMAL PRECIPITATION FOR NORTHWESTERN
PORTIONS OF ALASKA, ASSOCIATED WITH THE MID-LEVEL TROUGH OVER THE BERING SEA.
BELOW NORMAL PRECIPITATION IS FAVORED FOR MUCH OF THE REMAINDER OF ALASKA UNDER
POSITIVE 500-HPA HEIGHT DEPARTURES. 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,
MESOSCALE CONVECTIVE SYSTEM (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 EASTERN GREAT
LAKES, OHIO AND TENNESSEE VALLEYS, APPALACHIANS, AND EAST COAST STATES FROM
GEORGIA NORTHEASTWARD TO MAINE, ASSOCIATED WITH THE MID-LEVEL TROUGH OVER THE
EASTERN CONUS. BELOW NORMAL PRECIPITATION CHANCES ARE INCREASED FROM ARIZONA
EAST-SOUTHEASTWARD ACROSS MUCH OF NEW MEXICO AND TEXAS TO THE LOWER MISSISSIPPI
VALLEY, AND ALSO SOUTHERN FLORIDA, AS INDICATED BY THE CONSOLIDATION
PRECIPITATION TOOL. THIS IS CONSISTENT WITH AN EXPECTED GRADUAL RETRACTION OF
THE SUBTROPICAL RIDGE BACK TOWARDS THE SOUTHWESTERN AND SOUTH-CENTRAL STATES,
AND A RELATIVELY WEAK MONSOON. INCREASED CHANCES OF BELOW NORMAL PRECIPITATION
ARE ALSO INDICATED OVER THE UPPER MISSISSIPPI VALLEY AND UPPER GREAT LAKES
REGION, FAR ENOUGH AWAY FROM STORM TRACKS.
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: NEAR AVERAGE, 3 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 05 - 11 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 MID-LEVEL
TROUGH OVER FAR EASTERN RUSSIA IS FORECAST TO PROGRESS TO THE BERING
SEA/ALEUTIANS, THOUGH POSITIVE 500-HPA HEIGHT ANOMALIES CONTINUE TO DOMINATE
ALL BUT FAR SOUTHWESTERN ALASKA. HEIGHT DEPARTURES IN EXCESS OF +90 METERS ARE
ANTICIPATED OVER NORTHERN ALASKA AS SHOWN ON THE MANUAL HEIGHT BLEND. MID-LEVEL
TROUGHING IS EXPECTED TO DEAMPLIFY 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 SLIGHTLY BELOW NORMAL 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 MOSTLY POSITIVE 500-HPA
HEIGHT ANOMALIES. THE PROJECTED RETRACTION OF THE RIDGE BACK TOWARDS THE
SOUTHWESTERN CONUS FAVORS ABOVE NORMAL SURFACE TEMPERATURES OVER MOST AREAS
WEST OF THE CONTINENTAL DIVIDE, AND APPROXIMATELY THE SOUTHERN THIRD OF THE
CONUS EAST OF THE DIVIDE. PROBABILITIES FOR ABOVE NORMAL TEMPERATURES EXCEED
70% OVER PORTIONS OF FLORIDA AND EASTERN TEXAS. THERE ARE ELEVATED ODDS FOR
BELOW NORMAL SURFACE TEMPERATURES FROM THE NORTHERN AND CENTRAL PLAINS EASTWARD
ACROSS THE UPPER HALF OF THE MISSISSIPPI VALLEY, GREAT LAKES REGION, OHIO
VALLEY, CENTRAL AND NORTHERN APPALACHIANS, AND EAST COAST STATES FROM NORTHERN
NORTH CAROLINA NORTHEASTWARD TO MAINE. THE AREA OF FAVORED BELOW NORMAL
TEMPERATURES OVER THE NORTHERN AND CENTRAL PLAINS IS ATTRIBUTED TO RECENT
CALIBRATION AND FORECAST PRECIPITATION FACTORS AS NOTED EARLIER IN THE 6-10 DAY
TEMPERATURE SECTION. THE REMAINING AREA OF FAVORED BELOW NORMAL TEMPERATURES
(OVER APPROXIMATELY THE NORTHEAST QUARTER OF THE CONUS) IS ASSOCIATED WITH A
MID-LEVEL TROUGH AND NEAR TO BELOW NORMAL 500-HPA HEIGHTS, AND IS CONSISTENT
WITH REFORECAST-CALIBRATED TEMPERATURE GUIDANCE. A FINAL CONSIDERATION IS THAT
THE GEFS CONSISTENTLY MAINTAINS AN AREA OF FAVORED ABOVE NORMAL TEMPERATURES
ACROSS THE VICINITY OF THE UPPER MISSISSIPPI VALLEY DURING WEEK-2, BUT THIS HAS
VERY LITTLE SUPPORT FROM REFORECAST-CALIBRATED AND BIAS-CORRECTED TEMPERATURES
FROM THE OTHER ENSEMBLE MEAN MODELS.
WITH INCREASING ENSEMBLE SPREAD AND FAIRLY SMALL 500-HPA HEIGHT ANOMALIES IN
THE MANUAL BLEND OF DYNAMICAL MODEL FORECASTS, THE WEEK-2 PRECIPITATION OUTLOOK
REMAINS SOMEWHAT UNCERTAIN ACROSS MOST OF THE DOMAIN. 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 EASTERN ALASKA 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 MINOR
ADJUSTMENTS. ABOVE NORMAL PRECIPITATION IS FAVORED AHEAD OF THE EASTERN PACIFIC
MID-LEVEL TROUGH FROM ABOUT THE NORTHWESTERN QUARTER OF THE CONUS ACROSS MUCH
OF THE GREAT PLAINS, CENTRAL AND SOUTH-CENTRAL MISSISSIPPI VALLEY, OHIO AND
TENNESSEE VALLEYS, THE APPALACHIANS, AND EAST COAST STATES FROM NORTHERN
FLORIDA TO MAINE. 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. ANOMALOUSLY DRY CONDITIONS ARE INDICATED
ACROSS THE SOUTHERN ROCKIES, SOUTHERN TEXAS, AND ADJACENT PARTS OF LOUISIANA.
THIS AREA OF FAVORED ANOMALOUS DRYNESS IS ASSOCIATED WITH THE ANTICIPATED
REDUCED PRESENCE OF THE SUBTROPICAL RIDGE IN THE SOUTHEAST, AND A RETRACTION OF
THE RIDGE TOWARDS THE SOUTHWESTERN CONUS.
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: NEAR 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:
19940811 - 19610728 - 19530724 - 19890708 - 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:
19940810 - 19610727 - 19890709 - 19970725 - 19530724
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 03 - 07 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA N A WYOMING B A
UTAH A A ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA N N S DAKOTA B A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA N N IOWA A N MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN N N
ILLINOIS A N MISSISSIPPI A N MICHIGAN B N
INDIANA N N OHIO B N KENTUCKY N A
TENNESSEE A A 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 B A
MARYLAND B A DELAWARE B A VIRGINIA N A
N CAROLINA N A S CAROLINA A A GEORGIA A A
FL PNHDL A N FL PENIN A N AK N SLOPE A N
AK ALEUTIAN A B AK WESTERN A N 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 05 - 11 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A N
SRN CALIF A N IDAHO N A NEVADA A A
W MONTANA N A E MONTANA B A WYOMING B A
UTAH A N ARIZONA A N COLORADO N 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 A MISSOURI N A
ARKANSAS A A LOUISIANA A N WISCONSIN B N
ILLINOIS B N MISSISSIPPI A N MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B A
TENNESSEE N A 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 A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA N A S CAROLINA A A GEORGIA A A
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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