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FXUS06 KWBC 081945
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE OCTOBER 08 2024
6-10 DAY OUTLOOK FOR OCT 14 - 18 2024
TODAY’S ENSEMBLE MEAN MODELS (GEFS, ECENS, AND CMCE) ARE IN VERY GOOD AGREEMENT
ON THE LARGE-SCALE FEATURES OF THE PREDICTED 500-HPA CIRCULATION PATTERN OVER
THE FORECAST DOMAIN DURING THE 6-10 DAY PERIOD. MID-LEVEL ANOMALOUS RIDGES AND
POSITIVE HEIGHT ANOMALIES ARE DEPICTED OVER THE KAMCHATKA PENINSULA AND MOST OF
THE BERING SEA, AND OVER THE WESTERN AND CENTRAL CONTIGUOUS U.S. (CONUS). FOR
THE LATTER AREA, A POSITIVE HEIGHT ANOMALY CENTER IS PREDICTED IN THE VICINITY
OF MANITOBA WITH MAXIMUM HEIGHT ANOMALIES DEPICTED BY THE MANUAL HEIGHT BLEND
TO BE GREATER THAN +150 METERS. MID-LEVEL TROUGHS ARE PREDICTED TO EXTEND FROM
ALASKA SOUTHWARD ACROSS THE GULF OF ALASKA, AND ALSO OVER THE EASTERN CONUS.
THE MANUAL HEIGHT BLEND DEPICTS MAXIMUM NEGATIVE HEIGHT ANOMALIES GREATER THAN
-60 METERS OVER THE GULF OF ALASKA AND THE VICINITY OF THE
NORTHEAST/MID-ATLANTIC. COMPARED TO YESTERDAY’S OFFICIAL 6-10 DAY HEIGHT BLEND,
THE PREDICTED AMPLITUDES OF THE TWO MEAN TROUGHS HAVE DECREASED BY ABOUT 50%.
IN THE VICINITY OF HAWAII, MID-LEVEL HEIGHTS ARE FORECAST TO BE ABOVE AVERAGE.
ABOVE NORMAL TEMPERATURE CHANCES ARE ELEVATED WEST OF A LINE THAT EXTENDS
APPROXIMATELY FROM NORTHERN MINNESOTA TO WEST TEXAS. THIS IS.ASSOCIATED WITH A
LARGE ANOMALOUS RIDGE AND FAIRLY STRONG POSITIVE HEIGHT ANOMALIES EXPECTED OVER
THIS AREA. THIS IS WELL SUPPORTED BY REFORECAST-CALIBRATED, BIAS-CORRECTED, AND
RAW TEMPERATURES FROM THE GEFS, ECENS, AND CMCE ENSEMBLE MEANS. CHANCES OF
ABOVE NORMAL TEMPERATURES EXCEED 80% IN THE VICINITY OF THE GREAT SALT LAKE.
BELOW NORMAL TEMPERATURE CHANCES ARE ENHANCED OVER THE EASTERN CONUS, EAST OF A
LINE THAT EXTENDS FROM MOST OF THE MISSISSIPPI VALLEY AND GREAT LAKES REGION.
THIS AREA OF FAVORED BELOW NORMAL TEMPERATURES IS SUBSTANTIALLY LARGER ON ITS
WESTERN FLANK THAN WAS PREDICTED YESTERDAY, THOUGH THIS WILL LIKELY BE A FAST
MOVING SHOT OF ANOMALOUSLY COLD AIR. ODDS EXCEED 70% OVER A SIGNIFICANT
PORTION OF THE EASTERN CONUS. IN ALASKA, BELOW NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER WESTERN PORTIONS OF THE STATE, WITH ABOVE NORMAL TEMPERATURES
FAVORED OVER THE EASTERN MAINLAND. THIS IS IN AGREEMENT WITH THE AUTO AND
CONSOLIDATED TEMPERATURE TOOLS. THE ERF-CON AND AUTOMATED TEMPERATURE TOOLS FOR
HAWAII FAVOR INCREASED ODDS OF ABOVE NORMAL TEMPERATURES, CONSISTENT WITH THE
PREDICTED 500-HPA HEIGHT ANOMALY PATTERN AND NEAR TO SLIGHTLY ABOVE NORMAL
SEA-SURFACE TEMPERATURES.
BELOW NORMAL PRECIPITATION CHANCES ARE INCREASED OVER THE MAJORITY OF THE
CONUS, WITH MAXIMUM CHANCES EXCEEDING 60% OVER PORTIONS OF THE MID-LOWER
MISSISSIPPI VALLEY AND WESTERN TENNESSEE. THIS IS WELL SUPPORTED BY THE VARIOUS
ENSEMBLE MEAN MODELS AND TOOLS, AND BY THE FORECAST OF A LARGE MID-LEVEL RIDGE
WITH WELL ABOVE-NORMAL HEIGHTS OVER MUCH OF THE LOWER 48 STATES. OVER THE
INTERIOR EAST, THIS IS ATTRIBUTED TO DRIER NORTHWEST FLOW ANTICIPATED WEST OF A
MEAN TROUGH AXIS PREDICTED NEAR THE APPALACHIANS. THERE IS A SLIGHT TILT IN THE
ODDS FAVORING ANOMALOUS DRYNESS OVER SOUTHWESTERN ALASKA, WEST OF A MEAN TROUGH
AXIS PREDICTED OVER THE STATE. ABOVE NORMAL PRECIPITATION CHANCES ARE ELEVATED
OVER MOST OF THE REMAINDER OF ALASKA, ASSOCIATED WITH ONSHORE FLOW AT LOW AND
MID LEVELS AND SURFACE LOW PRESSURE CENTERED NEAR KODIAK ISLAND. THIS BROAD
REGION OF FAVORED ABOVE NORMAL PRECIPITATION CHANCES EXTENDS SOUTHWARD INTO THE
NORTHWESTERN CONUS. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED ACROSS FLORIDA,
IN THE EASTERLY FLOW SOUTH OF A SURFACE HIGH FORECAST NEAR THE SOUTHERN
APPALACHIANS. INCIDENTALLY, SOME LAKE-EFFECT PRECIPITATION IS FAVORED FOR THE
LOWER GREAT LAKES, BUT IT IS A BIT EARLY IN THE SEASON FOR ACCUMULATING
SNOWFALL. NEVERTHELESS, IT IS A REMINDER THAT WINTER IS NOT TOO FAR AWAY. FOR
HAWAII, A SUBJECTIVE CONSENSUS BETWEEN THE ERF-CON AND AUTOMATED PRECIPITATION
TOOLS FAVORS NEAR NORMAL PRECIPITATION FOR THE ISLANDS.
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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
VERY GOOD AGREEMENT AMONG THE PREDICTED MODEL HEIGHT FIELDS, AND SURFACE
TEMPERATURE AND PRECIPITATION TOOLS, OFFSET BY AN EXPECTED RAPID TEMPERATURE
TRANSITION (FROM BELOW NORMAL TO ABOVE NORMAL) ACROSS THE CENTRAL CONUS DURING
THE OUTLOOK PERIOD.
8-14 DAY OUTLOOK FOR OCT 16 - 22 2024
THE WEEK-2 MEAN CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN IS PREDICTED TO
SIGNIFICANTLY DEAMPLIFY, ACCOMPANIED BY EASTWARD PROGRESSION. THE ANOMALOUS
RIDGE OVER THE WESTERN AND CENTRAL CONUS IS FORECAST TO ADVANCE RAPIDLY ACROSS
MUCH OF THE EASTERN CONUS ACCOMPANIED BY RISING 500-HPA HEIGHTS, WITH THE
EXCEPTION OF THE GULF STATES WHERE NEAR NORMAL HEIGHTS ARE FAVORED. THE EASTERN
CONUS TROUGH PREDICTED DURING THE EARLIER 6-10 DAY PERIOD IS FORECAST TO
RAPIDLY FILL WHILE LIFTING OUT TO THE NORTHEAST. OVER ALASKA, THE TROUGH
PREDICTED DURING THE EARLIER 6-10 DAY PERIOD IS EXPECTED TO WEAKEN RAPIDLY, AS
HEIGHTS RISE ACROSS THE REGION. AN ELONGATED 500-HPA TROUGH OVER EASTERN
SIBERIA MAY EXTEND AS FAR EAST AS NORTHERN ALASKA, INCREASING THE ODDS FOR
PRECIPITATION THERE DURING THE OUTLOOK PERIOD.
ABOVE NORMAL TEMPERATURE CHANCES ARE ELEVATED ACROSS MOST OF THE CONTIGUOUS
U.S. DURING WEEK-2. THIS INCLUDES MOST AREAS WEST OF A LINE THAT EXTENDS FROM
THE EASTERN GREAT LAKES TO THE TEXAS COAST. MAXIMUM PROBABILITIES MAY EXCEED
70% OVER THE EASTERN DAKOTAS AND NORTHWESTERN MINNESOTA. ENSEMBLE MEAN MODELS
AND MOST TEMPERATURE TOOLS CONTINUE TO BE IN VERY GOOD AGREEMENT ON THIS
WIDESPREAD ANOMALOUS WARMTH. MOST OF THE REMAINING AREA IN THE
EASTERN/SOUTHEASTERN CONUS IS FAVORED TO HAVE BELOW NORMAL TEMPERATURES,
RELATED TO A PREDICTED RAPIDLY WEAKENING 500-HPA TROUGH. THE RAPIDLY WEAKENING
TROUGH PREDICTED OVER ALASKA AND ENSUING INCREASE IN FAST WESTERLY FLOW
SUPPORTS MOSTLY NEAR NORMAL TEMPERATURES ACROSS THE STATE. EXCEPTIONS INCLUDE
THE ALEUTIANS, ALASKA PENINSULA, AND SOUTHEAST ALASKA, WHERE BELOW NORMAL
TEMPERATURES ARE FAVORED, AND A SMALL-SCALE AREA OF FAVORED ABOVE NORMAL
TEMPERATURES OVER THE NORTHEAST CORNER OF ALASKA. ABOVE NORMAL TEMPERATURE
CHANCES CONTINUE TO BE ELEVATED OVER THE HAWAIIAN ARCHIPELAGO.
DURING WEEK-2 BELOW NORMAL PRECIPITATION CHANCES ARE INCREASED OVER THE
MAJORITY OF THE CONUS, AS WAS THE CASE WITH THE EARLIER 6-10 DAY PERIOD, BASED
ON THE SAME REASONING. ABOVE NORMAL PRECIPITATION REMAINS FAVORED OVER FLORIDA,
THOUGH THIS SIGNAL IS WEAKENING. ABOVE NORMAL PRECIPITATION IS FAVORED TO
INCREASE IN COVERAGE ACROSS THE NORTHWESTERN CONUS, RELATED TO THE SOUTHWARD
PUSH OF ENERGETIC WESTERLIES AND THE PACIFIC STORM TRACK ACROSS THIS REGION.
ACROSS THE WESTERN GULF COAST STATES AND THE SOUTHERN PLAINS, NEAR TO SLIGHTLY
ABOVE NORMAL 500-HPA HEIGHTS ARE FORECAST DURING WEEK-2, SOUTH OF THE LARGE
ANOMALOUS RIDGE CENTERED OVER THE UPPER GREAT LAKES REGION. THIS, AND THE
FORECAST OF SURFACE HIGH PRESSURE NEARING THE SOUTHEAST COAST, SUGGESTS A
POTENTIAL INCREASE IN MOIST RETURN FLOW (AND SUBSEQUENT PRECIPITATION) FROM THE
GULF INTO TEXAS AND THE PROXIMITY OF A WEAK BAROCLINIC ZONE. MOST OF ALASKA IS
FAVORED TO HAVE ABOVE NORMAL PRECIPITATION DURING WEEK-2 AS ENERGY ASSOCIATED
WITH AN ELONGATED MID-LEVEL TROUGH APPROACHES THE STATE FROM THE WEST. NEAR TO
ABOVE NORMAL PRECIPITATION IS FAVORED OVER THE HAWAIIAN ISLANDS, BASED ON A
SUBJECTIVE CONSENSUS BETWEEN THE ERF-CON AND AUTOMATED PRECIPITATION TOOLS.
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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
CONTINUING GOOD AGREEMENT BETWEEN THE VARIOUS MID-LEVEL HEIGHT FORECASTS,
OFFSET BY INHERENT DIFFICULTIES TRYING TO PREDICT DETAILS OF SHORTWAVE TROUGHS
EMBEDDED WITHIN A PREDICTED ZONAL FLOW PATTERN.
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
OCTOBER 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:
19920928 - 20010922 - 19551011 - 19551006 - 20041004
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:
19551010 - 19920929 - 20010921 - 19870917 - 19951012
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 14 - 18 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A B ARIZONA A N COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS N B OKLAHOMA N B
N TEXAS N B S TEXAS N B W TEXAS A B
MINNESOTA N B IOWA B B MISSOURI B B
ARKANSAS B B LOUISIANA B B WISCONSIN B B
ILLINOIS B B MISSISSIPPI B B MICHIGAN B B
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B 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 B NEW JERSEY B N W VIRGINIA B B
MARYLAND B B DELAWARE B N VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B B FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B N AK INT BSN A A
AK S INT A N AK SO COAST A A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 16 - 22 2024
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 N
W MONTANA A A E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A B
NEW MEXICO A B N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA N B WISCONSIN A B
ILLINOIS A B MISSISSIPPI B B MICHIGAN A B
INDIANA A B OHIO A B KENTUCKY N B
TENNESSEE B B ALABAMA B B NEW YORK N B
VERMONT N B NEW HAMP N B MAINE N B
MASS N B CONN N B RHODE IS N B
PENN N B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B N GEORGIA B B
FL PNHDL B N FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N N AK PNHDL B 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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