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FXUS06 KWBC 141903
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON AUGUST 14 2023
6-10 DAY OUTLOOK FOR AUG 20 - 24 2023
A STRONG MID-LEVEL RIDGE IS FORECAST TO BE CENTERED IN THE CENTRAL CONTIGUOUS
UNITED STATES (CONUS) DURING THE 6 TO 10 DAY PERIOD. MEANWHILE, WEAK TROUGHING
IS FORECAST ACROSS THE CANADIAN MARITIMES THAT IS FORECAST TO STRENGTHEN AND
RETROGRADE INTO THE NORTHEAST NEAR THE END OF THE PERIOD. WEAK TROUGHING MAY
ALSO DEVELOP ALONG THE WEST COAST AND THAT WOULD ENHANCE SURFACE AND MID-LEVEL
MOISTURE INTO THE WEST. STRONG NEGATIVE 500-HPA HEIGHT ANOMALIES ARE FAVORED
NORTHWEST OF ALASKA WITH POSITIVE ANOMALIES CENTERED ACROSS SOUTHEASTERN
ALASKA, SETTING UP A STRONG BAROCLINIC ZONE ACROSS MUCH OF THE STATE.
THE DOMINANT RIDGE ACROSS THE MIDDLE OF THE CONUS SETS UP A LARGE AREA TO BE
FAVORED FOR ABOVE-NORMAL TEMPERATURES FROM MOST OF THE EASTERN SEABOARD TO THE
GREAT BASIN. THE STRONGEST CHANCES FOR ABOVE-NORMAL ARE FOCUSED ACROSS THE
CENTRAL PLAINS AND MIDDLE AND LOWER MISSISSIPPI RIVER VALLEY. THERE REMAINS
SOME DISAGREEMENT BETWEEN THE ECMWF AND GEFS REFORECAST TOOLS FOR THE STRENGTH
OF ABOVE-NORMAL OVER PARTS OF THE MIDWEST. HOWEVER, WITH RIDGING FIRMLY
ESTABLISHED, A BLEND OF THE REFORECAST TOOLS STRENGTHS IS FAVORED. IN THE
INTERIOR WEST, BELOW-NORMAL IS SLIGHTLY FAVORED DUE TO INCREASED MOISTURE AS A
RESULT OF A GULF SURGE FROM A TROPICAL SYSTEM. IN ALASKA, ABOVE NORMAL IS
FAVORED ACROSS MUCH OF THE EASTERN HALF OF THE STATE BENEATH STRONG POSITIVE
500-HPA HEIGHT ANOMALIES. IN THE WESTERN PORTIONS OF THE STATE, NEAR TO
BELOW-NORMAL IS FAVORED DUE TO CONTINUED TROUGHING.
THE SOUTHWEST MONSOON IS FAVORED TO BE STRONGLY REINVIGORATED BY THE 6 TO 10
DAY PERIOD WITH STRONG ODDS TOWARDS ABOVE-NORMAL PRECIPITATION BEING FAVORED
ACROSS MUCH OF THE WEST. A TROPICAL SYSTEM IS FAVORED TO DEVELOP AND WILL
ENHANCE MIDDLE AND LOWER LEVEL MOISTURE ACROSS MUCH OF THE WEST HELPING
INITIATE PRECIPITATION. THE STRONGEST ODDS FOR PRECIPITATION ARE DISPLACED
SLIGHTLY WEST OF NORMAL MONSOON PRECIPITATION AND ARE FOCUSED ACROSS THE LOWER
COLORADO RIVER VALLEY NORTH INTO NEVADA AND IDAHO WHERE NORMAL PRECIPITATION IS
LOWER. A SECOND MAXIMA IS FAVORED ACROSS PARTS OF EASTERN MONTANA AND NORTH
DAKOTA WHERE RAW AND REFORECAST TOOLS INDICATE STRONG CHANCES FOR ABOVE-NORMAL
PRECIPITATION. MEANWHILE, ACROSS MUCH OF THE CENTRAL AND EASTERN CONUS, BENEATH
STRONG POSITIVE 500-HPA HEIGHT ANOMALIES, BELOW-NORMAL PRECIPITATION IS
FAVORED. EXCEPTIONS TO THIS ARE IN NEW ENGLAND, WHERE NEGATIVE 500-HPA HEIGHTS
MAY BUILD IN AND BRING CHANCES FOR PRECIPITATION, AND IN PARTS OF SOUTH FLORIDA
AND SOUTHERN TEXAS, WHERE EASTERLY WAVES MAY BRING INCREASED CHANCES FOR
PRECIPITATION. IN ALASKA, BELOW-NORMAL PRECIPITATION IS FAVORED ACROSS
SOUTHEASTERN PORTIONS OF THE STATE WITH THE STRONGEST PROBABILITIES IN
SOUTHEAST ALASKA BENEATH STRONG POSITIVE 500-HPA HEIGHT ANOMALIES. IN THE
NORTHWEST MAINLAND, ABOVE-NORMAL PRECIPITATION IS FAVORED NEAR MID-LEVEL
TROUGHING.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 10% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 30% OF TODAY'S
0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S OPERATIONAL 0Z
ECMWF CENTERED ON DAY 8, AND 20% 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,
AMPLIFIED PATTERN AND GOOD AGREEMENT AMONG THE TOOLS IS OFFSET BY THE LIKELY
SCATTERED NATURE OF HEAVY PRECIPITATION IN THE WEST.
8-14 DAY OUTLOOK FOR AUG 22 - 28 2023
DURING THE WEEK-2 PERIOD, ABOVE-NORMAL 500-HPA HEIGHT ANOMALIES ACROSS THE
CENTRAL CONUS AT THE ONSET OF THE PERIOD INDUCE MEAN RIDGING FOR WEEK-2.
HOWEVER, THESE POSITIVE HEIGHT ANOMALIES ARE FORECAST TO FALL AND RETRACT NORTH
BY THE MIDDLE AND END OF THE PERIOD. MEANWHILE, TROUGHING MAY DEVELOP IN THE
NORTHEAST WITH NEAR TO SLIGHTLY NEGATIVE 500-HPA HEIGHT ANOMALIES IN THIS
REGION. ALONG THE WEST COAST, NEAR TO BELOW-NORMAL 500-HPA HEIGHTS ARE FORECAST
BRINGING TROUGHING TO THE REGION. IN THE GULF OF ALASKA, POSITIVE 500-HPA
HEIGHT ANOMALIES REMAIN. HOWEVER, NORTHWEST OF ALASKA THE STRONG NEGATIVE
500-HPA HEIGHT ANOMALIES THAT HAVE BEEN PERSISTENT FOR SOME TIME NOW LOOK
LIKELY TO WEAKEN AND BECOME MORE NEAR-NORMAL.
RIDGING ACROSS MUCH OF THE CONUS AT THE BEGINNING OF THE PERIOD BRINGS
INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF THE COUNTRY. THE
STRONGEST CHANCES, GREATER THAN 70%, FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST
ACROSS PORTIONS OF THE LOWER-MISSISSIPPI VALLEY AND GULF COAST.THERE CONTINUES
TO BE DISAGREEMENT BETWEEN THE GEFS (STRONGER) AND ECMWF (WEAKER) REFORECAST
TOOLS ON THE STRENGTH OF ABOVE-NORMAL CHANCES IN THE MIDWEST, WITH A WEAKENING
RIDGE DURING THE PERIOD, LOWER PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ARE
FAVORED RELATIVE TO AREAS FARTHER TO THE SOUTH. IN THE WEST, CONTINUED ENHANCED
MOISTURE FROM AN ADDITIONAL TROPICAL SYSTEM MAY HELP TO ENHANCE CLOUD COVER AND
REDUCE TEMPERATURES, THEREFORE, ONLY A SLIGHT TILT TOWARDS ABOVE-NORMAL
TEMPERATURES ARE FORECASTED ACROSS THE INTERIOR WEST. IN ALASKA, ABOVE-NORMAL
TEMPERATURES REMAIN FAVORED ACROSS THE EASTERN PORTIONS OF THE STATE BENEATH
STRONG POSITIVE HEIGHT ANOMALIES. NEAR NORMAL IS FAVORED ACROSS WESTERN ALASKA,
NEAR CONTINUED TROUGHING EVEN AS 500-HPA HEIGHT ANOMALIES MOVE TOWARDS
NEAR-NORMAL.
ABOVE-NORMAL PRECIPITATION REMAINS FAVORED IN MUCH OF THE WEST WITH THE
STRONGEST PROBABILITIES, ABOVE 50%, CENTERED IN IDAHO. A SECOND TROPICAL SYSTEM
MAY HELP TO MAINTAIN ABOVE-NORMAL PRECIPITATION DURING MUCH OF THE PERIOD,
HOWEVER, THE TRACK OF THIS POTENTIAL SYSTEM IS STILL VERY UNCERTAIN. THEREFORE,
PROBABILITIES ARE REDUCED RELATIVE TO THE 6 TO 10 DAY PERIOD. BELOW-NORMAL
PRECIPITATION IS FAVORED ACROSS TENNESSEE, OHIO, AND MISSISSIPPI RIVER VALLEYS
DURING THE WEEK-2 PERIOD. AS THE 500-HPA HEIGHT ANOMALIES WEAKEN BY THE MIDDLE
AND END OF THE PERIOD AND UNCERTAINTY INCREASES, THE PROBABILITIES ARE REDUCED
FROM THE 6 TO 10 DAY PERIOD BUT REMAIN IN MUCH THE SAME VICINITY. ABOVE-NORMAL
PRECIPITATION IS FAVORED IN THE NORTHEAST AS BELOW-NORMAL 500-HPA HEIGHTS BEGIN
TO DEVELOP. MEANWHILE, A SLIGHT TILT TOWARDS ABOVE-NORMAL IS FAVORED IN
SOUTHERN TEXAS AND FLORIDA WHERE SOME EASTERLY WAVES MAY HELP TO INCREASE
PRECIPITATION. IN ALASKA, ABOVE-NORMAL PRECIPITATION REMAINS FAVORED IN THE
NORTHWEST PARTS OF THE STATE AND BELOW NORMAL IN SOUTHEAST ALASKA WITH THE
HEIGHT PATTERN NOT CHANGING MUCH FROM THE 6 TO 10 DAY PERIOD.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 11, 35% 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: BELOW AVERAGE, 2 OUT 5, AN ONGOING
PATTERN CHANGE AND REDUCED SIGNALS IN THE PRECIPITATION FORECAST ACROSS THE
CONUS IS OFFSET BY BETTER AGREEMENT IN THE TEMPERATURE TOOLS.
FORECASTER: RYAN BOLT
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:
19920803 - 19920727 - 19560822 - 19610828 - 19560827
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:
19920802 - 19560826 - 19580821 - 19610827 - 19580726
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 20 - 24 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF A A
SRN CALIF B A IDAHO N A NEVADA B A
W MONTANA N A E MONTANA A A WYOMING A A
UTAH B A ARIZONA B A COLORADO A A
NEW MEXICO A B N DAKOTA A A S DAKOTA A A
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A A IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE N N
MASS A N CONN A N RHODE IS A N
PENN A B NEW JERSEY A N W VIRGINIA A B
MARYLAND A B DELAWARE A B VIRGINIA A B
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE N A
AK ALEUTIAN N N AK WESTERN N A AK INT BSN A A
AK S INT A N AK SO COAST A B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 22 - 28 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS A B MISSISSIPPI A B MICHIGAN A N
INDIANA A B OHIO A B KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK N N
VERMONT B N NEW HAMP B A MAINE B A
MASS B A CONN N A RHODE IS B A
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 B
FL PNHDL A N FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN N A AK INT BSN A A
AK S INT A N AK SO COAST A N AK PNHDL A B
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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