868
FXUS06 KWBC 111902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED OCTOBER 11 2023
6-10 DAY OUTLOOK FOR OCT 17 - 21 2023
TODAY’S DYNAMICAL MODEL SOLUTIONS ARE IN GOOD AGREEMENT REGARDING AN AMPLIFIED
500-HPA GEOPOTENTIAL HEIGHT PATTERN ACROSS NORTH AMERICA DURING THE 6-10 DAY
PERIOD. MID-LEVEL TROUGHS ARE FORECAST ACROSS THE CENTRAL PACIFIC AND OVER THE
EASTERN CONUS, WITH THE MANUAL HEIGHT BLEND DEPICTING ASSOCIATED AREAS OF
BELOW-NORMAL HEIGHTS ACROSS SOUTHWESTERN ALASKA AND MOST OF THE EASTERN CONUS
RESPECTIVELY. CONVERSELY, AMPLIFIED RIDGING IS PREDICTED OVER THE WESTERN CONUS
WITH A BROAD AREA OF POSITIVE 500-HPA HEIGHT ANOMALIES EXTENDING THROUGH MUCH
OF THE NORTH-CENTRAL CONUS AND GREAT LAKES, CANADA, AND MAINLAND AND SOUTHEAST
ALASKA. THE 0Z ECMWF ENSEMBLE HAS WEAKENED THE SHORTWAVE TROUGH PREDICTED TO
MOVE ACROSS THE WESTERN CONUS COMPARED TO YESTERDAY, AND IS IN BETTER AGREEMENT
WITH THE 0Z GEFS AND CANADIAN ENSEMBLES, DEPICTING STRONGER RIDGING. WEAKLY
POSITIVE 500-HPA ANOMALIES ARE PREDICTED ACROSS HAWAII.
MEAN TROUGHING IN THE EAST FAVORS INCREASED PROBABILITIES OF BELOW-NORMAL
TEMPERATURES ACROSS MUCH OF THE EASTERN CONUS, EXTENDING THROUGH PARTS OF THE
CENTRAL AND SOUTHERN PLAINS. THE HIGHEST PROBABILITIES (GREATER THAN 80
PERCENT) ARE INDICATED ACROSS PARTS OF THE SOUTHEAST AND FLORIDA UNDERNEATH
SURFACE HIGH PRESSURE. INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE
FAVORED ACROSS MUCH OF THE WESTERN AND NORTH-CENTRAL CONUS DUE TO ENHANCED
RIDGING AND POSITIVE MID-LEVEL HEIGHT ANOMALIES. RETURN SOUTHWESTERLY FLOW
AROUND THE SURFACE HIGH OVER THE SOUTHEAST FAVORS INCREASING CHANCES OF NEAR-
TO ABOVE-NORMAL TEMPERATURES ACROSS PARTS OF THE UPPER AND MIDDLE MISSISSIPPI
VALLEY, GREAT LAKES, AND NORTHEAST. PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES
ARE INCREASED ACROSS MUCH OF ALASKA DUE TO ENHANCED SOUTHERLY MID-LEVEL FLOW
AND POSITIVE HEIGHT ANOMALIES FORECAST ACROSS MUCH OF THE MAINLAND, WITH A
SLIGHT TILT TOWARD INCREASED BELOW-NORMAL TEMPERATURE PROBABILITIES ACROSS THE
FAR WESTERN MAINLAND AND PARTS OF THE ALEUTIANS. NEAR- TO ABOVE-NORMAL
TEMPERATURES ARE FAVORED ACROSS MOST OF HAWAII, WITH A SLIGHT TILT TOWARD
INCREASED BELOW-NORMAL TEMPERATURE PROBABILITIES ACROSS THE SOUTHERN PORTION OF
THE BIG ISLAND DUE IN PART TO BELOW-NORMAL SEA SURFACE TEMPERATURES.
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION HAVE DECREASED ACROSS THE CENTRAL
CONUS COMPARED TO YESTERDAY IN THE ECMWF REFORECAST TOOL GIVEN THE WEAKER
SHORTWAVE TROUGH. HOWEVER, THE ECMWF REFORECAST TOOL MAINTAINS A SLIGHT TILT
TOWARD ABOVE-NORMAL PRECIPITATION ACROSS THE CENTRAL CONUS, AND EXTENDING INTO
PARTS OF THE EAST. HOWEVER, THE OVERALL SYNOPTIC PATTERN GENERALLY FAVORS
BELOW-NORMAL PRECIPITATION OVER MOST OF THE CONUS, AND THIS IS SUPPORTED BY THE
STATISTICAL ANALOGS. THEREFORE, TODAY’S FORECAST INDICATES GREATER CHANCES FOR
NEAR- TO BELOW-NORMAL PRECIPITATION ACROSS MUCH OF THE CONUS, WITH THE HIGHEST
PROBABILITIES OF BELOW-NORMAL PRECIPITATION FAVORED OVER THE SOUTHWESTERN
CONUS. SLIGHT TILTS TOWARD INCREASED ABOVE-NORMAL PRECIPITATION PROBABILITIES
ARE HIGHLIGHTED ACROSS NORTHERN WASHINGTON STATE, THE COASTAL MID-ATLANTIC AND
NORTHEAST, AND THE FLORIDA PENINSULA CONSISTENT WITH BOTH THE GEFS AND ECMWF
REFORECAST TOOLS. STRONG ONSHORE FLOW AND SURFACE LOW PRESSURE, POSSIBLY
ASSOCIATED WITH THE REMNANT OF WHAT IS CURRENTLY SUPER TYPHOON BOLAVEN OVER THE
WESTERN PACIFIC, FAVOR INCREASED CHANCES OF ABOVE-NORMAL PRECIPITATION ACROSS
MOST OF MAINLAND AND SOUTHEAST ALASKA, WITH BELOW-NORMAL PRECIPITATION CHANCES
INCREASED CLOSER TO THE BACKSIDE OF THE TROUGH AXIS ACROSS THE FAR WESTERN
MAINLAND AND THE ALEUTIANS. TROUGHING SHIFTING SOUTHWARD ACROSS THE CENTRAL
PACIFIC FAVORS INCREASED ABOVE-NORMAL PRECIPITATION PROBABILITIES ACROSS THE
NORTHERN HAWAIIAN ISLANDS, WITH CHANCES FOR BELOW-NORMAL PRECIPITATION
REMAINING SLIGHTLY ELEVATED ACROSS THE BIG ISLAND.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
MODEL AGREEMENT ON THE 500-HPA FLOW PATTERN ACROSS NORTH AMERICA, OFFSET BY
SOME UNCERTAINTY IN THE PRECIPITATION FORECAST ACROSS THE CONUS.
8-14 DAY OUTLOOK FOR OCT 19 - 25 2023
A GENERALLY PERSISTENT 500-HPA GEOPOTENTIAL HEIGHT PATTERN IS FORECAST DURING
WEEK-2 RELATIVE TO THE 6-10 DAY PERIOD. RIDGING REMAINS FORECAST ACROSS MUCH OF
THE WESTERN CONUS, WITH TROUGHING OVER THE CENTRAL PACIFIC, TO THE SOUTH OF
ALASKA. THE MID-LEVEL HEIGHT PATTERN OVER THE EASTERN CONUS IS MORE VARIABLE,
BUT THE 0Z ECMWF, GEFS, AND CANADIAN ENSEMBLES ALL SHOW TROUGHING RELOADING BY
THE END OF THE PERIOD AS THE NORTH ATLANTIC OSCILLATION POTENTIALLY RETURNS TO
A NEGATIVE PHASE IN LATE-OCTOBER. TODAY’S MANUAL 500-HPA HEIGHT BLEND FOR THE
WEEK-2 PERIOD DEPICTS NEAR- TO BELOW-NORMAL HEIGHTS ACROSS THE EASTERN CONUS
AND ABOVE-NORMAL HEIGHTS OVER THE WESTERN CONUS, AND EXTENDING NORTHWARD
THROUGH WESTERN CANADA AND ALASKA. SLIGHTLY BELOW-NORMAL MID-LEVEL HEIGHTS ARE
PREDICTED ACROSS HAWAII DUE TO GREATER INFLUENCE FROM THE CENTRAL PACIFIC
TROUGHING.
THERE ARE ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES ACROSS MUCH OF
THE WESTERN AND NORTHERN TIER OF THE CONUS DUE TO RIDGING AND INCREASED
SOUTHWESTERLY FLOW AROUND SURFACE HIGH PRESSURE OVER THE SOUTHEAST,
PARTICULARLY EARLY IN THE PERIOD. PROBABILITIES FOR BELOW-NORMAL TEMPERATURES
ARE INCREASED ACROSS MUCH OF THE EAST, FROM THE MID-ATLANTIC AND OHIO VALLEY
SOUTHWARD THROUGH MOST OF FLORIDA. MUCH OF THE EASTERN CONUS, ESPECIALLY THE
NORTHEAST, COULD SEE A PERIOD OF MODERATING TEMPERATURES IN THE EARLY TO MIDDLE
PART OF WEEK-2, BEFORE BELOW-NORMAL TEMPERATURES RETURN AT THE END OF THE
PERIOD AS LONGWAVE TROUGHING POTENTIALLY DEVELOPS. IN ALASKA, CHANCES FOR NEAR-
TO ABOVE-NORMAL TEMPERATURES ARE INCREASED ACROSS MOST OF THE STATE DUE TO
INCREASED SOUTHERLY MID-LEVEL FLOW. NEAR- TO ABOVE-NORMAL TEMPERATURES ARE ALSO
FAVORED ACROSS MOST OF HAWAII, WITH A SLIGHT TILT TOWARD INCREASED BELOW-NORMAL
TEMPERATURE PROBABILITIES PERSISTING ACROSS THE SOUTHERN PORTION OF THE BIG
ISLAND DUE TO BELOW-NORMAL SEA SURFACE TEMPERATURES.
AS IN THE 6-10 DAY OUTLOOK, THE ECMWF AND GEFS REFORECAST TOOLS ARE OUT OF
PHASE REGARDING THE PRECIPITATION FORECAST EAST OF THE ROCKIES. THE ECMWF
(GEFS) REFORECAST TOOL CONTINUES TO LEAN WETTER (DRIER). THE STATISTICAL ANALOG
GUIDANCE SUPPORTS INCREASED CHANCES FOR BELOW-NORMAL PRECIPITATION ACROSS MOST
OF THE CONUS, ALONG WITH THE UNCALIBRATED 0Z ECMWF, GEFS, AND CANADIAN
ENSEMBLES. FOR TODAY’S FORECAST, BELOW-NORMAL PRECIPITATION PROBABILITIES ARE
INCREASED ACROSS MOST OF THE WESTERN AND CENTRAL CONUS, WITH NEAR- TO
ABOVE-NORMAL PRECIPITATION FAVORED ACROSS PARTS OF THE SOUTH-CENTRAL AND
SOUTHWESTERN CONUS. DEPENDING ON THE EXACT ORIENTATION OF TROUGHING, THERE IS
AT LEAST SOME POTENTIAL FOR SOME ENHANCED MOISTURE OR EVEN A SURFACE LOW TO
DEVELOP ALONG THE EASTERN SEABOARD, TILTING THE ODDS TOWARD NEAR- TO
ABOVE-NORMAL PRECIPITATION FOR THE PERIOD AS A WHOLE. ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE FORECAST TO REMAIN ELEVATED ACROSS MOST OF
ALASKA DUE TO THE AFOREMENTIONED TROUGHING AND ENHANCED SOUTHERLY FLOW. THIS
SAME TROUGH FAVORS AN INCREASE IN ABOVE-NORMAL PRECIPITATION CHANCES ACROSS
NORTHERN HAWAII DURING WEEK-2, WITH NEAR- TO BELOW-NORMAL PRECIPITATION
REMAINING FAVORED ACROSS THE SOUTHERN HAWAII ISLANDS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 30% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO
SOME AGREEMENT REGARDING THE OVERALL SYNOPTIC PATTERN, OFFSET BY UNCERTAINTY IN
THE TOOLS AND MORE TRANSIENT FEATURES OVER THE CONUS DURING THE PERIOD.
FORECASTER: THOMAS COLLOW
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 - 20001008 - 20051025 - 20071011 - 20010925
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 - 20051024 - 20071012 - 19810920 - 20001007
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 17 - 21 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B 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 N N DAKOTA A N S DAKOTA A B
NEBRASKA A B KANSAS N N OKLAHOMA N N
N TEXAS B N S TEXAS B N W TEXAS A N
MINNESOTA A N IOWA N B MISSOURI B B
ARKANSAS B B LOUISIANA B B WISCONSIN A B
ILLINOIS N B MISSISSIPPI B B MICHIGAN N B
INDIANA B B OHIO B N KENTUCKY B B
TENNESSEE B B ALABAMA B B NEW YORK N N
VERMONT N B NEW HAMP N N MAINE N B
MASS N N CONN N A RHODE IS N A
PENN B N NEW JERSEY B A W VIRGINIA B N
MARYLAND B N DELAWARE B A VIRGINIA B N
N CAROLINA B N S CAROLINA B B GEORGIA B B
FL PNHDL B B FL PENIN B A AK N SLOPE A A
AK ALEUTIAN N B AK WESTERN N N AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 19 - 25 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A B NRN CALIF A B
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A N WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI N B
ARKANSAS N N LOUISIANA N N WISCONSIN A N
ILLINOIS N B MISSISSIPPI N N MICHIGAN N N
INDIANA N N OHIO N N KENTUCKY B N
TENNESSEE B N ALABAMA B N NEW YORK N N
VERMONT A A NEW HAMP A A MAINE A A
MASS N A CONN N A RHODE IS N A
PENN N N NEW JERSEY N N W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN N A AK INT BSN A A
AK S INT N A AK SO COAST N A AK PNHDL A 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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