157
FXUS06 KWBC 121902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU OCTOBER 12 2023
6-10 DAY OUTLOOK FOR OCT 18 - 22 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 AMPLIFIED RIDGING PREDICTED OVER THE WESTERN CONUS. TODAY’S
MANUAL HEIGHT BLEND DEPICTS ABOVE-NORMAL MID-LEVEL HEIGHTS ACROSS THE WESTERN
AND NORTHERN TIER OF THE CONUS, EXTENDING THROUGHOUT MUCH OF CANADA AND ALASKA.
CONVERSELY, NEAR- TO BELOW-NORMAL MID-LEVEL HEIGHTS ARE INDICATED THROUGHOUT
THE SOUTHEASTERN QUADRANT OF THE CONUS, EXTENDING NORTHWARD THROUGH THE
NORTHEASTERN COASTAL PLAIN. WEAKLY POSITIVE 500-HPA ANOMALIES ARE PREDICTED
ACROSS HAWAII.
MEAN TROUGHING IN THE EAST FAVORS INCREASED PROBABILITIES OF BELOW-NORMAL
TEMPERATURES ACROSS PARTS OF THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS,
SOUTHEAST, AND MID-ATLANTIC. THE HIGHEST PROBABILITIES (GREATER THAN 60
PERCENT) ARE INDICATED ACROSS SOUTHERN GEORGIA AND NORTHERN 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 EXPANDING ACROSS PARTS OF THE UPPER AND MIDDLE
MISSISSIPPI VALLEY, OHIO VALLEY, GREAT LAKES, AND NORTHEAST. PROBABILITIES FOR
ABOVE-NORMAL TEMPERATURES ARE INCREASED ACROSS EASTERN ALASKA DUE TO ENHANCED
SOUTHERLY MID-LEVEL FLOW AND POSITIVE HEIGHT ANOMALIES, WITH INCREASED
PROBABILITIES FOR BELOW-NORMAL TEMPERATURE FAVORED ACROSS THE WESTERN MAINLAND
AND PARTS OF THE ALEUTIANS CONSISTENT WITH THE ECMWF REFORECAST TOOL AND
UNCALIBRATED GUIDANCE FROM THE 0Z GEFS, ECMWF AND CANADIAN ENSEMBLES. 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.
THERE IS LOW CONFIDENCE IN THE PRECIPITATION FORECAST ACROSS THE CONUS EAST OF
THE ROCKIES GIVEN CONFLICTING SIGNALS IN THE MODEL GUIDANCE. RETURN FLOW AROUND
SURFACE HIGH PRESSURE FAVORS AN UPTICK IN PRECIPITATION CHANCES ALONG THE GULF
OF MEXICO COAST, WITH THE ECMWF REFORECAST TOOL DEPICTING ELEVATED
PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION EXTENDING THROUGH MUCH OF THE
EASTERN CONUS. THE GEFS IS MORE TONED DOWN, FAVORING INCREASED CHANCES FOR
BELOW-NORMAL PRECIPITATION ACROSS MUCH OF THE INTERIOR EASTERN CONUS, EXTENDING
TO THE CENTRAL GULF COAST, AND SLIGHT TILT TOWARD ELEVATED ABOVE-NORMAL
PRECIPITATION PROBABILITIES ACROSS PARTS OF THE PLAINS AND ADJACENT AREAS OF
THE MISSISSIPPI VALLEY. SOME OF THIS MOISTURE MAY ALSO IMPACT THE EASTERN
SEABOARD, WITH SEVERAL 0Z ECMWF ENSEMBLE MEMBERS INDICATING SURFACE LOW
FORMATION ACROSS THE NORTHEAST LATER IN THE PERIOD. DUE TO THE UNCERTAINTY,
NEAR TO SLIGHTLY ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INDICATED ACROSS
THE SOUTH-CENTRAL AND SOUTHEASTERN CONUS IN TODAY’S FORECAST. NEAR TO
BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ELEVATED FOR MUCH OF THE GREAT
LAKES, OHIO VALLEY, MID-ATLANTIC, AND NORTHEAST, WITH THE EXCEPTION OF COASTAL
NEW ENGLAND WHICH HAS A SLIGHT TILT TOWARD INCREASED ABOVE-NORMAL PRECIPITATION
PROBABILITIES. THERE IS GREATER CONFIDENCE FOR INCREASED CHANCES FOR
BELOW-NORMAL PRECIPITATION OVER THE WESTERN CONUS RELATED TO THE PREDICTED
RIDGING.
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 SOUTHWESTERN 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 EAST OF THE
ROCKIES.
8-14 DAY OUTLOOK FOR OCT 20 - 26 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, CONSISTENT WITH TELECONNECTION ANALYSIS WITH THE CENTRAL
PACIFIC TROUGH AND A POTENTIAL RETURN TO A NEGATIVE PHASE OF THE NORTH ATLANTIC
OSCILLATION 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 MID-ATLANTIC AND SOUTHEAST. 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. CHANCES FOR ABOVE-NORMAL TEMPERATURES ARE INCREASED ACROSS EASTERN
ALASKA DUE TO INCREASED SOUTHERLY MID-LEVEL FLOW, WITH A SLIGHT TILT WORD
INCREASED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS THE WESTERN
MAINLAND AND ALASKA PENINSULA CONSISTENT WITH THE ECMWF REFORECAST TOOL AND
UNCALIBRATED 0Z ECMWF, GEFS, AND CANADIAN GUIDANCE. 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.
BELOW-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED ACROSS MUCH OF THE
WESTERN TWO-THIRDS OF THE CONUS UNDERNEATH POSITIVE MID-LEVEL HEIGHT ANOMALIES
AND CONSISTENT WITH STATISTICAL ANALOG GUIDANCE. ELEVATED NEAR- TO ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE FAVORED ACROSS THE EASTERN CONUS WHERE
TROUGHING FAVORS ENHANCED MOISTURE AND POSSIBLY SURFACE LOW PRESSURE NEAR THE
EASTERN SEABOARD AS DEPICTED IN THE 0Z ECMWF ENSEMBLE. 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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
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 - 20071011 - 20051025 - 20001008 - 20010926
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:
20081003 - 20051024 - 19960921 - 20071013 - 20001007
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 18 - 22 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 B N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA N N
N TEXAS N A S TEXAS N A W TEXAS A N
MINNESOTA A B IOWA A N MISSOURI N N
ARKANSAS N N LOUISIANA B N WISCONSIN A B
ILLINOIS N N MISSISSIPPI B N MICHIGAN A B
INDIANA N N OHIO N B KENTUCKY N N
TENNESSEE B N ALABAMA B N NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS N N CONN N N RHODE IS N A
PENN N N NEW JERSEY N N W VIRGINIA N B
MARYLAND N N DELAWARE N N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B A AK N SLOPE N A
AK ALEUTIAN B B AK WESTERN B B AK INT BSN A A
AK S INT N A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 20 - 26 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 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 B W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI N B
ARKANSAS N B LOUISIANA N N WISCONSIN A B
ILLINOIS N B MISSISSIPPI N N MICHIGAN A B
INDIANA N B OHIO N B KENTUCKY N B
TENNESSEE B N ALABAMA B N NEW YORK N N
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN N N RHODE IS N A
PENN N N NEW JERSEY N N W VIRGINIA B N
MARYLAND N N DELAWARE N N VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA B N
FL PNHDL B A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN B A AK INT BSN N 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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