861
FXUS06 KWBC 251902
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 25 2024
6-10 DAY OUTLOOK FOR OCT 31 - NOV 04, 2024
AN AMPLIFIED 500-HPA HEIGHT PATTERN IS FORECAST ACROSS THE CONTIGUOUS U.S.
(CONUS) AT THE START OF THE 6-10 DAY FORECAST PERIOD, WITH RIDGING (TROUGHING)
OVER THE EAST (WEST). A POTENTIAL REALIGNMENT OF MID-LATITUDE FEATURES MAY
BEGIN TOWARD THE END OF THE PERIOD, WITH THE 0Z ECENS, GEFS, AND CMCE DEPICTING
THE INITIAL TROUGHING OVER THE WEST WEAKENING AND SHIFTING EASTWARD TOWARD THE
EAST-CENTRAL CONUS, WITH MORE RIDGING AND POSITIVE HEIGHT ANOMALIES DEVELOPING
OVER THE WEST BY DAY-10. THE ECENS IS SLIGHTLY MORE PROGRESSIVE WITH THE
PATTERN COMPARED TO THE GEFS AND CMCE, SHOWING MORE OF A TROUGHING SIGNATURE
OVER THE EASTERN CONUS BY DAY-10, VERSUS THE GEFS AND CMCE WHICH HANG ON TO
RIDGING ACROSS THE NORTHEAST AND KEEP THE TROUGHING OVER THE GREAT PLAINS.
FOLLOWING BRIEF RIDGING ACROSS EASTERN ALASKA AT THE OUTSET OF THE PERIOD, A
MORE PERSISTENT LONGWAVE TROUGH IS PREDICTED TO BUILD OVER ALASKA. THE MANUAL
HEIGHT BLEND FOR THE PERIOD AS A WHOLE DEPICTS POSITIVE HEIGHT ANOMALIES FOR
THE EASTERN HALF OF THE CONUS, WITH THE HIGHEST ANOMALIES (+90 METERS) OVER THE
NORTHEAST, NORTHERN MID-ATLANTIC, AND OHIO VALLEY. CONVERSELY, NEGATIVE HEIGHT
ANOMALIES ARE INDICATED FROM THE PACIFIC COAST TO THE HIGH PLAINS, EXTENDING
THROUGH MUCH OF ALASKA, AND INCREASING IN MAGNITUDE OVER THE BERING SEA.
SLIGHTLY ABOVE-NORMAL HEIGHTS ARE PREDICTED ACROSS HAWAII.
EXPANSIVE POSITIVE 500-HPA HEIGHT ANOMALIES PREDICTED OVER THE CENTRAL AND
EASTERN CONUS FAVOR ELEVATED PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES FROM
THE GREAT PLAINS TO THE EASTERN SEABOARD. RECORD WARMTH IS POSSIBLE ON
HALLOWEEN (DAY-6) ACROSS PARTS OF THE NORTHEAST WHERE HIGH TEMPERATURES ARE
PREDICTED TO BE 15-20 DEG F ABOVE NORMAL. CONVERSELY, BELOW-NORMAL TEMPERATURES
ARE FAVORED FROM THE WEST COAST TO THE ROCKIES ASSOCIATED WITH INCREASED
TROUGHING OVER THE REGION, ALTHOUGH TEMPERATURES ACROSS THE WEST ARE LIKELY TO
MODERATE OR EVEN FLIP TO ABOVE-NORMAL BY THE END OF THE PERIOD AS THE MID-LEVEL
PATTERN TRANSITIONS TO MORE RIDGING. TROUGHING OVER THE BERING SEA FAVORS
INCREASED SOUTHERLY FLOW DEVELOPING ACROSS MUCH OF MAINLAND ALASKA LEADING TO
ELEVATED ODDS OF NEAR- TO SLIGHTLY ABOVE-NORMAL TEMPERATURES. BELOW-NORMAL
TEMPERATURE PROBABILITIES REMAIN SLIGHTLY ELEVATED ACROSS PARTS OF THE FAR
WESTERN MAINLAND AND THE ALEUTIANS UNDERNEATH LARGER NEGATIVE MID-LEVEL HEIGHT
ANOMALIES, AND OVER SOUTHEAST ALASKA DUE TO WEAKER FLOW ALOFT COMPARED TO
FURTHER UPSTREAM. ANOMALOUSLY LOW SEA ICE ACROSS THE BEAUFORT SEA FAVORS
ABOVE-NORMAL TEMPERATURES ACROSS THE NORTH SLOPE. HIGH PROBABILITIES OF
ABOVE-NORMAL TEMPERATURES REMAIN FORECAST ACROSS HAWAII, CONSISTENT WITH THE
GEFS AND ECENS REFORECAST CONSOLIDATION.
TROUGHING INITIALLY OVER THE WESTERN CONUS AND GRADUALLY PROGRESSING EASTWARD
TILTS THE ODDS TOWARDS ABOVE-NORMAL PRECIPITATION OVER MUCH OF THE CONUS. THE
HIGHEST ODDS (GREATER THAN 60 PERCENT) ARE OVER THE SOUTHERN PLAINS DUE TO
STRONG BAROCLINIC FORCING AND POTENTIAL FOR A STATIONARY FRONT TO SET-UP ACROSS
THE REGION. THE GEFS REFORECAST TOOL ALSO CONTINUES TO TREND HIGHER WITH
ABOVE-NORMAL PRECIPITATION PROBABILITIES OVER THIS AREA, FALLING MORE IN LINE
WITH THE PERSISTENTLY WET ECENS REFORECAST TOOL. MUCH OF THE COASTAL
MID-ATLANTIC AND NORTHEAST U.S. TILTS TOWARDS BELOW-NORMAL PRECIPITATION WITH
SURFACE HIGH PRESSURE CENTERED NEAR THE EAST COAST. ABOVE-NORMAL PRECIPITATION
CHANCES ARE ELEVATED ACROSS PARTS OF FLORIDA AND THE SOUTHEAST DUE TO A
POSSIBLE INCREASE IN TROPICAL MOISTURE ORIGINATING IN THE CARIBBEAN. THE
SYNOPTIC PATTERN OVER THE ALASKA REGION TENDS TO FAVOR STORMIER CONDITIONS OVER
THE GULF OF ALASKA AND ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE STATE SOUTH
OF THE BROOKS RANGE. PREVAILING WINDS OVER THE NORTH PACIFIC CROSS A LONG FETCH
OF WARM WATERS, FAVORING NEAR- TO ABOVE-NORMAL PRECIPITATION FOR HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON
DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
MODEL AGREEMENT REGARDING THE INITIAL MID-LEVEL HEIGHT PATTERN, OFFSET BY
INCREASING UNCERTAINTY REGARDING A REALIGNMENT OF THE MAJOR SYNOPTIC FEATURES
LATER IN THE PERIOD.
8-14 DAY OUTLOOK FOR NOV 02 - 08 2024
THE WEEK-2 FORECAST EVOLUTION BECOMES MORE UNCLEAR ACROSS THE CONUS AS THE
AMPLIFIED MID-LEVEL HEIGHT PATTERN IN THE DAYS PRIOR BREAKS DOWN, WITH HIGH
VARIABILITY NOTED IN THE INDIVIDUAL MODEL ENSEMBLE MEMBERS. THIS IS LIKELY
RELATED TO SEVERAL COMPETING MODES OF VARIABILITY IN THE TROPICS AND HIGH
LATITUDES INCLUDING THE ARCTIC OSCILLATION TRENDING FROM A POSITIVE TO NEUTRAL
PHASE, THE MJO REACHING THE WESTERN HEMISPHERE (PHASE 8), AND THE INFLUENCE
FROM THE TRANSITION TO LA NINA. THE WEEK-2 MANUAL HEIGHT BLEND DEPICTS WEAKLY
ABOVE-NORMAL HEIGHTS (+30 METERS) ACROSS MUCH OF THE EASTERN HALF OF THE CONUS,
SIGNIFICANTLY LESS THAN IN THE 6-10 DAY PERIOD. POSITIVE HEIGHT ANOMALIES ARE
FORECAST ACROSS PARTS OF THE WEST AS MORE RIDGING MOVES OVER THE REGION
REPRESENTING A QUICK TRANSITION FROM THE PRIOR PERIOD. NEAR-NORMAL HEIGHTS
EXTEND FROM THE SOUTHWEST THROUGH THE HIGH PLAINS, INTO THE UPPER MISSISSIPPI
VALLEY AS THE MID-LEVEL PATTERN BECOMES MORE TRANSIENT OVER THOSE AREAS.
TROUGHING AND NEGATIVE HEIGHT ANOMALIES ARE FAVORED TO PERSIST ACROSS MUCH OF
ALASKA, WITH NEAR-NORMAL HEIGHTS FORECAST FOR HAWAII.
UNSEASONABLE WARMTH IS LIKELY TO CONTINUE OVER THE EASTERN U.S. EARLY IN
WEEK-2. WHILE A DOWNWARD TREND IN TEMPERATURES IS PLAUSIBLE TOWARD THE END OF
THE PERIOD, THE PERIOD-AVERAGE STILL SUPPORTS ELEVATED PROBABILITIES FOR
ABOVE-NORMAL TEMPERATURES. A MORE TRANSIENT MID-LEVEL FLOW PATTERN AND ENHANCED
PACIFIC FLOW FAVORS THESE ELEVATED ABOVE-NORMAL TEMPERATURE PROBABILITIES TO
EXTEND BACK THROUGH THE GREAT PLAINS, WITH THE TRANSITION TO MORE RIDGING IN
THE WEST FAVORING ELEVATED ODDS OF ABOVE-NORMAL TEMPERATURES NEAR THE WEST
COAST. NEAR TO SLIGHTLY BELOW-NORMAL TEMPERATURES ARE PREDICTED ACROSS THE
INTERMOUNTAIN AND SOUTHWEST. TROUGHING OVER ALASKA FAVORS INCREASED
SOUTHWESTERLY FLOW OVER MUCH OF THE MAINLAND AND SOUTHEAST ALASKA LEADING TO
INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES. PROBABILITIES FOR BELOW-NORMAL
TEMPERATURES ARE INCREASED ACROSS THE FAR WESTERN MAINLAND AND PARTS OF THE
ALEUTIANS UNDERNEATH INCREASED NORTHERLY FLOW ON THE BACKSIDE OF THE TROUGH.
HAWAII CONTINUES TO TILT STRONGLY TOWARDS ABOVE-NORMAL TEMPERATURES, CONSISTENT
WITH THE ECENS AND GEFS REFORECAST CONSOLIDATION.
MUCH OF THE EASTERN TWO-THIRDS OF THE CONUS TILTS TOWARDS NEAR TO ABOVE-NORMAL
PRECIPITATION FOR WEEK-2 DUE TO MORE TRANSIENT MID-LEVEL FEATURES, ALTHOUGH
THERE IS MORE UNCERTAINTY RESULTING IN GENERALLY LOWER PROBABILITIES. THE
HIGHEST CHANCES (GREATER THAN 50 PERCENT) REMAIN ACROSS THE SOUTHERN HIGH
PLAINS WHERE A LINGERING BAROCLINIC ZONE MAY REMAIN, ESPECIALLY EARLY IN THE
PERIOD AS THE 0Z ECENS AND GEFS DEPICT A CUT-OFF LOW OVER THE SOUTHWEST
UNDERNEATH THE BUILDING RIDGE. THE ABOVE-NORMAL PRECIPITATION PROBABILITIES
ALSO EXTEND TO PARTS OF THE EAST DUE TO THE POTENTIAL FOR INTERACTION BETWEEN
TROPICAL MOISTURE MOVING NORTHWARD AND INCOMING TROUGHING, ALTHOUGH THE TIMING
OF THESE FEATURES ARE CRITICAL IN DETERMINING IF AND WHERE HIGHER PRECIPITATION
TOTALS SET UP. ODDS ARE SLIGHTLY ELEVATED FOR BELOW-NORMAL PRECIPITATION WEST
OF THE ROCKIES DUE TO A STRONGER INFLUENCE FROM RIDGING. TROUGHING OVER ALASKA
FAVORS A PERSISTENT STORMY PATTERN ACROSS THE STATE, WITH THE HIGHEST ODDS FOR
ABOVE-NORMAL PRECIPITATION ACROSS THE SOUTHERN COAST. ABOVE-NORMAL
PRECIPITATION REMAINS FAVORED ACROSS HAWAII, WITH THE EXCEPTION OF KAUAI, WHERE
NEAR-NORMAL PRECIPITATION IS FORECAST.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% 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 OF 5, DUE TO
SOME MODEL AGREEMENT ESPECIALLY EARLY IN THE PERIOD, OFFSET BY LARGE SPREAD
DEVELOPING IN MODEL ENSEMBLES.
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
NOVEMBER 21.
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:
19831005 - 19561010 - 19711031 - 19821019 - 19811025
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:
19831005 - 19561010 - 19711101 - 19701014 - 19811026
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 31 - NOV 04, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B N
SRN CALIF B N IDAHO B A NEVADA B A
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B A ARIZONA B A COLORADO B A
NEW MEXICO B A N DAKOTA A A S DAKOTA N A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A B CONN A B RHODE IS A B
PENN A N NEW JERSEY A B W VIRGINIA A N
MARYLAND A N DELAWARE A B VIRGINIA A N
N CAROLINA A N S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN N A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 02 - 08 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N B OREGON A B NRN CALIF A B
SRN CALIF N N IDAHO N B NEVADA N B
W MONTANA N N E MONTANA A N WYOMING N N
UTAH N N ARIZONA N A COLORADO A A
NEW MEXICO A A N DAKOTA A N S DAKOTA A N
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A 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 A NEW JERSEY A N W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE A N
AK ALEUTIAN B A AK WESTERN N A AK INT BSN A A
AK S INT A A AK SO COAST A 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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