795
FXUS06 KWBC 131902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI OCTOBER 13 2023
6-10 DAY OUTLOOK FOR OCT 19 - 23 2023
THE DYNAMICAL MODEL SOLUTIONS FOR THE 6 TO 10 DAY 500-HPA HEIGHTS ARE IN GOOD
AGREEMENT ACROSS MUCH OF THE NORTHERN HEMISPHERE. STRONG POSITIVE 500-HPA
HEIGHT ANOMALIES ARE IN PLACE ACROSS WESTERN ALASKA, MUCH OF CANADA, AND THE
WESTERN CONTIGUOUS U.S. (CONUS). NEGATIVE 500-HPA HEIGHT ANOMALIES AND DEEP
TROUGHING ARE FAVORED IN THE NORTHEAST PACIFIC. A SECOND AREA OF NEGATIVE
500-HPA HEIGHT ANOMALIES IS FORECAST IN THE SOUTHEASTERN CONUS. THE ECMWF
INDICATES CHANCES FOR A CUT-OFF MID-LEVEL LOW TO DEVELOP BUT DOESN’T HAVE
SUPPORT FROM THE GEFS OR CANADIAN. IN HAWAII, THERE IS SOME DISAGREEMENT
BETWEEN THE ENSEMBLES ON NEGATIVE OR POSITIVE 500-HPA HEIGHT ANOMALIES WITH THE
GEFS BRINGING MORE NEGATIVE ANOMALIES AND THE ECMWF BEING SLIGHTLY MORE
POSITIVE.
ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE WESTERN AND NORTHERN
CONUS DURING THE 6 TO 10 DAY PERIOD. THE STRONGEST CHANCES FOR ABOVE-NORMAL
TEMPERATURES ARE IN THE WESTERN CONUS WITH STRONG MID-LEVEL RIDGING DURING MOST
OF THE PERIOD AND GOOD AGREEMENT AMONG THE TOOLS. IN THE NORTHEASTERN CONUS
ABOVE-NORMAL TEMPERATURE CHANCES ARE SLIGHTLY STRONGER RELATIVE TO YESTERDAY
WITH TOOLS IN BETTER AGREEMENT. HOWEVER, THERE IS UNCERTAINTY IN THE EVOLUTION
OF A TROUGH ACROSS THE SOUTHEASTERN CONUS THAT REDUCES CONFIDENCE. ASSOCIATED
WITH THE TROUGH OVER THE SOUTHEAST, BELOW-NORMAL TEMPERATURES ARE FAVORED,
ALTHOUGH WITH LOWER CHANCES RELATIVE TO YESTERDAY. IN ALASKA, THE PATTERN LOOKS
MORE PROGRESSIVE WITH BELOW-NORMAL TEMPERATURE CHANCES MOVING FURTHER EAST
RELATIVE TO YESTERDAY SO THAT THE WESTERN TWO-THIRDS OF MAINLAND ALASKA ARE
FAVORED TO SEE BELOW-NORMAL TEMPERATURES. ABOVE-NORMAL TEMPERATURES REMAIN
FAVORED ACROSS PARTS OF THE ALEUTIAN ISLANDS AND SOUTHEAST ALASKA. IN HAWAII,
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE STATE EXCLUDING THE
ISLAND OF HAWAII WHERE NEAR-NORMAL IS FAVORED.
BENEATH STRONG MID-LEVEL RIDGING ACROSS MUCH OF THE WESTERN CONUS, BELOW-NORMAL
PRECIPITATION IS FAVORED. SLIGHT CHANCES FOR BELOW-NORMAL EXTEND NORTHEAST INTO
THE MIDWEST AND NORTHEAST WHERE CONTINUED POSITIVE 500-HPA HEIGHT ANOMALIES ARE
FAVORED TO REDUCE PRECIPITATION. ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED
IN PARTS OF THE PACIFIC NORTHWEST. ONSHORE FLOW IS FAVORED INTO THIS REGION
SUPPORTED BY REFORECAST TOOLS AND THE INTEGRATED VAPOR TRANSPORT TOOL SHOWING
SOME CHANCES FOR HEAVY PRECIPITATION INTO THE REGION. IN THE SOUTHEASTERN CONUS
REFORECAST TOOLS AND RAW MODEL GUIDANCE ARE IN BETTER AGREEMENT RELATIVE TO
YESTERDAY FOR AN AREA OF ABOVE-NORMAL PRECIPITATION IN THIS REGION BENEATH THE
500-HPA NEGATIVE HEIGHT ANOMALIES. IN ALASKA, STRENGTHENING RIDGING ACROSS THE
ALEUTIANS HAS REDUCED CHANCES FOR ABOVE-NORMAL PRECIPITATION INTO PORTIONS OF
SOUTHEAST AND SOUTH-CENTRAL ALASKA RELATIVE TO YESTERDAY BUT A SLIGHT TILT
TOWARDS ABOVE-NORMAL REMAINS IN SOUTHEAST ALASKA. BELOW-NORMAL PRECIPITATION IS
FAVORED ACROSS THE ALEUTIAN ISLANDS AND THE SOUTHWEST MAINLAND WHILE
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS THE NORTHERN TWO THIRDS OF
MAINLAND ALASKA. IN HAWAII, NEAR-NORMAL PRECIPITATION IS FAVORED FOR THE
ISLANDS WEST OF AND INCLUDING MAUI WITH BELOW-NORMAL PRECIPITATION FAVORED OVER
THE ISLAND OF HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 25% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 8, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, AND 30%
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, GOOD
MODEL AGREEMENT DURING THE 6 TO 10 DAY PERIOD INCREASES CONFIDENCE OFFSET BY
INCREASING DIFFERENCES UPSTREAM OF THE CONUS.
8-14 DAY OUTLOOK FOR OCT 21 - 27 2023
DURING THE 8 TO 14 DAY PERIOD, THE MID-LEVEL 500-HPA HEIGHT PATTERN BECOMES
MORE UNCERTAIN. THE GEFS IS PREDICTING NEAR TO BELOW-NORMAL 500-HPA HEIGHTS
ACROSS THE WESTERN CONUS BUT THIS IS OUT OF PHASE WITH PREVIOUS MODEL RUNS FROM
YESTERDAY, AS WELL AS THE ECMWF AND CANADIAN ENSEMBLES FROM TODAY. THE GEFS
ALSO IS FORECASTING THE STRONG CANADIAN RIDGE TO BREAK DOWN AND BRING
NEAR-NORMAL HEIGHTS TO THIS REGION. THE ECMWF AND CANADIAN SOMEWHAT AGREE ON
THIS BUT ARE SLOWER IN THE TRANSITION AND MAINTAIN A MORE SIMILAR PATTERN TO
THE 6 TO 10 DAY PERIOD. HOWEVER, MODELS CONTINUE TO AGREE WITH NEGATIVE 500-HPA
HEIGHT ANOMALIES FAVORED IN THE EASTERN CONUS INTO THE NORTH ATLANTIC. IN
ALASKA, POSITIVE HEIGHT ANOMALIES ARE GENERALLY FAVORED ACROSS THE STATE. IN
HAWAII, THE TROUGHING IN THE NORTH PACIFIC DURING THE 6 TO 10 DAY PERIOD IS
SHIFTING SOUTH AND IS FORECAST TO INTERACT WITH THE ISLANDS DURING WEEK-2.
ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS MUCH OF THE CONUS DURING WEEK-2.
THE STRONGEST CHANCES, EXCEEDING 50%, ARE ACROSS THE SOUTHWEST, ROCKIES AND
INTO THE NORTHERN PLAINS. IN THE NORTHEASTERN CONUS, ABOVE-NORMAL REMAINS
FAVORED WITH SLIGHTLY HIGHER AND MORE EXPANSIVE CHANCES RELATIVE TO YESTERDAY.
IN THE SOUTHEAST, BELOW-NORMAL IS SLIGHTLY FAVORED ACROSS PARTS OF SOUTH
CAROLINA, GEORGIA, AND FLORIDA. IN THE NORTHWESTERN CONUS, PROBABILITIES ARE
REDUCED RELATIVE TO YESTERDAY. THE GEFS ENSEMBLE IS BRINGING INCREASED CHANCES
FOR TROUGHING INTO THE REGION BUT SHOWS A WIDE SPREAD IN POSSIBLE SOLUTIONS.
THE ECMWF IS SLOWER IN BUILDING TROUGHING INTO THE WEST AND SO THEREFORE
MAINTAINS WARMER TEMPERATURES DURING WEEK-2. THEREFORE, ABOVE-NORMAL REMAINS
FAVORED BUT WITH LOWER PROBABILITIES DUE TO INCREASED UNCERTAINTY. IN ALASKA,
THE PROGRESSIVE PATTERN DESCRIBED IN THE 6 TO 10 DAY PERIOD CONTINUES. THE
BELOW-NORMAL TEMPERATURE CHANCES HAVE PROGRESSED EASTWARD AND ARE NOW OVER THE
EASTERN MAINLAND. MEANWHILE, NEAR-NORMAL IS NOW FAVORED IN MUCH OF MAINLAND
ALASKA. IN HAWAII, ABOVE-NORMAL TEMPERATURES ARE FAVORED ACROSS THE ISLAND
CHAIN WITH GOOD AGREEMENT AMONG THE TOOLS.
ABOVE-NORMAL PRECIPITATION REMAINS SLIGHTLY FAVORED IN PARTS OF THE
SOUTHEASTERN CONUS WHERE A LINGERING TROUGH MAY BRING CHANCES FOR PRECIPITATION
EARLY IN THE PERIOD. ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED IN PARTS OF THE
NORTHWESTERN CONUS WHERE SOME ONSHORE FLOW MAY BRING INCREASED PRECIPITATION
CHANCES TO PARTS OF THE INTERIOR NORTHWEST. ELSEWHERE, BROAD RIDGING GENERALLY
REDUCES CHANCES FOR PRECIPITATION AND NEAR- TO BELOW-NORMAL PRECIPITATION IS
FAVORED FROM CALIFORNIA, TO THE CENTRAL AND SOUTHERN PLAINS AND INTO THE
MIDWEST AS SUPPORTED BY THE ECMWF AND CANADIAN REFORECAST TOOLS. IN ALASKA,
NEAR- TO BELOW-NORMAL IS FAVORED FOR THE ALEUTIANS AND THE SOUTHERN MAINLAND
INTO SOUTHEAST ALASKA. MEANWHILE, ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS
THE NORTHERN TWO THIRDS OF MAINLAND ALASKA. IN HAWAII, A GRADIENT OF
BELOW-NORMAL PRECIPITATION IS FAVORED ON THE ISLAND OF HAWAII, NEAR-NORMAL
FAVORED ACROSS THE CENTRAL ISLANDS AND ABOVE-NORMAL PRECIPITATION IS SLIGHTLY
FAVORED FOR THE WESTERN ISLANDS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 10% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 35% OF
TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT 5, DYNAMICAL MODEL
GUIDANCE IS LESS CERTAIN ON THE EVOLUTION OF THE MID-LEVEL HEIGHT PATTERN
REDUCING CONFIDENCE RELATIVE TO THE 6 TO 10 DAY PERIOD.
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
OCTOBER 19.
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:
20081003 - 20071012 - 19791027 - 20051025 - 19581026
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:
20081002 - 20071014 - 19791026 - 20051024 - 19581026
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 19 - 23 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A N NRN CALIF A B
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A N E MONTANA A N WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A N OKLAHOMA N N
N TEXAS N N S TEXAS N N W TEXAS A N
MINNESOTA A B IOWA A N MISSOURI N N
ARKANSAS N N LOUISIANA B A WISCONSIN A N
ILLINOIS N N MISSISSIPPI B A MICHIGAN A N
INDIANA N N OHIO A N KENTUCKY N N
TENNESSEE N A ALABAMA B A 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 N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B A AK INT BSN B A
AK S INT B N AK SO COAST B B AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 21 - 27 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 A E MONTANA A A WYOMING A N
UTAH A N ARIZONA A N COLORADO A B
NEW MEXICO A B N DAKOTA A N S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A N IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A N
ILLINOIS A B MISSISSIPPI N N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE N N ALABAMA N 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 N N
N CAROLINA N N S CAROLINA N A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE N A
AK ALEUTIAN N B AK WESTERN N A AK INT BSN N A
AK S INT N N AK SO COAST B 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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