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FXUS06 KWBC 271919
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 27 2023
6-10 DAY OUTLOOK FOR NOV 02 - 06 2023
THE 6-10 DAY MEAN 500-HPA HEIGHT FORECASTS FROM THE LATEST ECMWF, GFS, AND
CANADIAN ENSEMBLE MEANS ARE IN FAIRLY GOOD AGREEMENT WITH REGARD TO THE
SYNOPTIC PATTERN, WITH MODERATE TROUGHING OVER THE NORTH PACIFIC, CONTINUED
ANOMALOUS RIDGING ACROSS ALASKA EXTENDING WEAKLY SOUTHEASTWARD INTO THE WESTERN
CONUS, AND A TROUGH OVER THE EASTERN CONTIGUOUS U.S. (CONUS) EXTENDING
NORTHWARD INTO NORTHEASTERN CANADA. THE OPERATIONAL GFS AND GEFS HAVE SHIFTED
TOWARD THE OTHER TOOLS, KEEPING 500-HPA HEIGHTS SLIGHTLY ABOVE NORMAL IN THE
NORTHWEST. TELECONNECTIONS FAVOR KEEPING ANOMALOUSLY LOW HEIGHTS OFFSHORE WEST
OF THE CONUS.
A COLD ARCTIC AIR MASS WILL HAVE MOVED SOUTHWARD OUT OF CANADA BEFORE THE 6-10
DAY PERIOD. THIS RESULTS IN BELOW-NORMAL TEMPERATURES BEING FAVORED ACROSS MUCH
OF THE CENTRAL AND EASTERN CONUS FOR THE PERIOD AS A WHOLE, BUT THE COLD SPELL
IS EXPECTED TO BE SHORT-LIVED. 500-HPA HEIGHTS ARE FORECAST TO REBOUND LATER IN
THE PERIOD, ALLOWING SURFACE HIGH PRESSURE TO SLIDE EASTWARD INTO THE ATLANTIC,
PULLING WARMER AIR INTO THE CENTRAL AND EASTERN CONUS FROM THE SOUTH. STILL,
PROBABILITIES OF BELOW-NORMAL TEMPERATURES FOR THE 5-DAY PERIOD AS A WHOLE
EXCEED 60 PERCENT OVER PORTIONS OF THE FAR NORTHERN PLAINS, AND ODDS TOP OUT
ABOVE 50 PERCENT ACROSS THE CENTRAL AND NORTHWESTERN GULF COAST REGION. FROM
THE HIGH PLAINS EASTWARD, ONLY SOUTHERN FLORIDA IS EXPECTED TO LARGELY MISS THE
COLD AIR OUTBREAK, WITH NEAR TO ABOVE-NORMAL TEMPERATURES FORECAST ACROSS MOST
OF THE PENINSULA. FARTHER WEST, THE ABOVE-NORMAL 500-HPA HEIGHTS ARE EXPECTED
TO KEEP TEMPERATURES ABOVE-NORMAL OVER THE CONUS WEST OF THE ROCKIES.
MID-LEVEL RIDGING OVER NORTHWESTERN NORTH AMERICA RESULTS IN SOUTHERLY FLOW
ALOFT AND ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES THROUGH MOST OF
ALASKA, ALTHOUGH THE TOOLS DERIVED FROM THE MODEL ENSEMBLES ARE INCONSISTENT
OVER THE CENTRAL MAINLAND. IN MOST OF THIS REGION, THERE IS NO TILT OF THE ODDS
TOWARD ANOMALOUS TEMPERATURES EXCEPT IN WEST-CENTRAL AREAS, WHERE ABOVE-NORMAL
SEA SURFACE TEMPERATURES NEARBY WILL LIKELY CAUSE CONDITIONS TO BE WARMER THAN
NORMAL. MEANWHILE, WEAKLY ABOVE-NORMAL SEA SURFACE TEMPERATURES IN THE HAWAII
REGION RESULT IN A SLIGHT TILT TOWARDS ABOVE-NORMAL TEMPERATURES FOR THE
ISLANDS.
EAST OF THE CENTRAL NORTH PACIFIC MID-LEVEL TROUGH, CYCLONICALLY-CURVED AND
DIFFLUENT MID-LEVEL FLOW INTO THE PACIFIC NORTHWEST FAVORS SURPLUS
PRECIPITATION OVER THE NORTHWEST QUARTER OF THE CONUS, WITH ODDS FOR
ABOVE-NORMAL AMOUNTS EXCEEDING 40 PERCENT FROM THE PACIFIC NORTHWEST EASTWARD
INTO THE NORTHERN HIGH PLAINS, WHICH IS FARTHER EAST THAN YESTERDAY, WITH MOST
TOOLS NOW SHOWING MORE MOISTURE INFLUX INTO THIS REGION. AT THE SAME TIME, ODDS
FOR WETNESS DECREASED SLIGHTLY ACROSS WASHINGTON, OREGON, AND SOME ADJACENT
LOCALES BECAUSE THE EUROPEAN ENSEMBLE MEAN AND DERIVED TOOLS BACKED OFF FROM
THE INTENSE PRECIPITATION FORECAST YESTERDAY. FARTHER SOUTH AND EAST, DRIER
THAN NORMAL CONDITIONS ARE FAVORED FOR MOST OF THE CONUS IN THE WAKE OF THE
COLD AIR SURGE UNDER ANTI-CYCLONIC MID-LEVEL FLOW. THE FLORIDA PENINSULA AND
COASTAL SECTIONS OF GEORGIA AND THE CAROLINA ARE EXCEPTIONS, WHERE TROPICAL OR
SUB-TROPICAL MOISTURE MAY ENHANCE RAINFALL ALONG A FRONTAL BOUNDARY LATER IN
THE PERIOD.
ABOVE-NORMAL 500-HPA HEIGHTS COVER ALASKA, WITH VERY LITTLE HEIGHT CHANGE
ACROSS THE STATE. THIS RESULTS IN AN UNUSUALLY WEAK MID-LEVEL FLOW THAT IS
USUALLY NOT CONDUCIVE TO THE DEVELOPMENT OF STRONG SURFACE LOW PRESSURE AND
HEAVY PRECIPITATION. AS A RESULT, SLIGHTLY ENHANCED CHANCES FOR SUBNORMAL
PRECIPITATION COVER THE ENTIRE STATE. BELOW-NORMAL PRECIPITATION IS FAVORED FOR
THE HAWAIIAN ISLANDS WITH A CONTINUED DRYING INFLUENCE FROM EL NINO CONDITIONS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 45% 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: BELOW AVERAGE, 2 OUT OF 5, DUE TO
FAIRLY GOOD AGREEMENT AMONG MODELS ON THE SYNOPTIC PATTERN, OFFSET BY DIVERGING
TEMPERATURE AND PRECIPITATION GUIDANCE FROM REFORECAST, BIAS-CORRECTED, AND
CALIBRATED MODEL ENSEMBLE TOOLS.
8-14 DAY OUTLOOK FOR NOV 04 - 10 2023
ACROSS THE CONUS, DYNAMICAL MODELS DEPICT A SLIGHTLY MORE AMPLIFIED PATTERN
THAN WAS FORECAST YESTERDAY. SLIGHTLY BELOW-NORMAL 500-HPA HEIGHTS ACROSS NEW
ENGLAND ARE EXPECTED TO EXTEND FARTHER SOUTH AND WEST, TO COVER APPROXIMATELY
THE NORTHEASTERN QUARTER OF THE CONUS. OVER THE NORTH PACIFIC, MODEL SOLUTIONS
KEEP THE TROUGH RELATIVELY UNCHANGED FROM THE 6-10 DAY PERIOD. THIS IS EXPECTED
TO KEEP CYCLONICALLY-CURVED, DIFFLUENT MID-LEVEL FLOW OVER THE WESTERN CONUS
WHICH MAY INCREASE SLIGHTLY TOWARD THE END OF WEEK-2. ABOVE-NORMAL HEIGHTS
PERSIST OVER ALASKA WHILE MODELS KEEP THE NORTH PACIFIC TROUGH JUST NORTH OF
HAWAII, RESULTING IN SLIGHTLY ABOVE-NORMAL MEAN 500-HPA HEIGHTS.
THE WARMING TREND BEGINNING LATE IN THE 6-10 DAY PERIOD SHOULD CONTINUE ACROSS
MUCH OF THE CONUS, BUT MOST GUIDANCE KEEPS CONDITIONS COOLER THAN YESTERDAY IN
THE EASTERN CONUS, PARTICULARLY IN THE NORTHEAST, IN CONJUNCTION WITH LOWER
500-HPA HEIGHTS COMPARED TO YESTERDAY. STILL, ABOVE-NORMAL TEMPERATURES ARE
EXPECTED TO DOMINATE THE WESTERN HALF OF THE CONUS, WITH ODDS EXCEEDING 60%
ACROSS A BROAD AREA COVERING MOST OF THE FAR WEST, GREAT BASIN, SOUTHERN
ROCKIES, AND SOUTHERN HIGH PLAINS. ENHANCED CHANCES FOR SUBNORMAL TEMPERATURES
COVER A LARGER AREA THAN YESTERDAY UNDER BELOW-NORMAL 500-HPA HEIGHTS,
EXTENDING FROM THE NORTHEAST WESTWARD ACROSS THE NORTHERN PLAINS. ODDS FOR
COLDER THAN NORMAL WEATHER IN THE NORTHERN PLAINS ARE ENHANCED DUE TO SNOW
COVER AND A FAVORABLE SET-UP FOR RADIATIONAL COOLING, WITH ENHANCED CHANCES
REACHING 50 PERCENT NEAR THE CANADIAN BORDER. ABOVE-NORMAL TEMPERATURES ARE
ALSO FAVORED FOR MUCH OF ALASKA, BUT WEAKENING SOUTHEASTERLY FLOW AND THE
POTENTIAL FOR SOME NORTHERLY WINDS LATER WEEK-2 LEAVES NEAR-NORMAL TEMPERATURES
FAVORED FOR MUCH OF THE CENTRAL AND EASTERN INTERIOR ALASKA. WEAKLY
ABOVE-NORMAL SEA SURFACE TEMPERATURES IN THE HAWAII REGION RESULT IN A SLIGHT
TILT TOWARDS ABOVE-NORMAL TEMPERATURES FOR THE ISLANDS.
THE SET-UP FAVORING ABOVE-NORMAL PRECIPITATION IS FORECAST TO REMAIN IN PLACE
ACROSS THE NORTHWESTERN CONUS FOR MOST OR ALL OF WEEK-2, KEEPING ENHANCED ODDS
FOR ABOVE-NORMAL PRECIPITATION IN PLACE THERE. FARTHER EAST, WEAK MID-LEVEL
HEIGHT ANOMALIES GENERALLY PRECLUDE EXCESSIVE PRECIPITATION, BUT WEAK FEATURES
ALSO INTRODUCE A LOT OF UNCERTAINTY. MOST GUIDANCE SLIGHTLY FAVORS BELOW-NORMAL
PRECIPITATION FROM THE SOUTHWEST THROUGH THE LOWER MISSISSIPPI VALLEY. AN
INFLUX OF MOISTURE FROM THE TROPICS AND LOWER MID-LATITUDES TILTS THE FORECAST
TOWARD ABOVE-NORMAL PRECIPITATION FROM SOUTHERN NEW ENGLAND SOUTHWARD ALONG THE
EAST COAST, ESPECIALLY FROM THE EASTERN CAROLINAS SOUTHWARD ACROSS THE FLORIDA
PENINSULA, CLOSER TO A STATIONARY FRONT THAT COULD EVOLVE IN THIS REGION.
HOWEVER, THERE IS SIGNIFICANT UNCERTAINTY INTRODUCED BY THE POTENTIAL FOR
TROPICAL CYCLONE DEVELOPMENT IN THE CARIBBEAN OR WESTERN NORTH ATLANTIC. ACROSS
ALASKA, SOME TOOLS INDICATE INCREASING CHANCES FOR PRECIPITATION AS WEEK-2
PROGRESSES ACROSS MOST OF THE STATE, BUT FOR WEEK-2 AS A WHOLE, ENHANCED
CHANCES FOR ABOVE-NORMAL PRECIPITATION ARE RESTRICTED TO THE EASTERN MAINLAND.
MUCH OF THE REST OF THE STATE IS FAVORED TO SEE NEAR-NORMAL PRECIPITATION
DURING THE PERIOD AS TOOLS GENERALLY SHOW MIXED GUIDANCE. . IN HAWAII, MOST
MODELS SHOW THE NORTH PACIFIC MID-LEVEL TROUGH EXPANDING SOUTHWARD, SLIGHTLY TO
THE WEST OF THE HAWAIIAN ISLANDS. THIS PLACES HAWAII TO THE EAST OF A MID-LEVEL
TROUGH AXIS, ENHANCING THE ODDS FOR INCREASED PRECIPITATION FROM THE 6-10 DAY
PERIOD. HOWEVER, IT IS NOT CLEAR WHETHER PRECIPITATION AMOUNTS WILL CLIMB ABOVE
NORMAL, SO NO TILT TOWARD EITHER EXTREME OF PRECIPITATION CAN BE DETERMINED.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 45% 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, WITH
FAIR AGREEMENT ON SYNOPTIC PATTERN AMONG DYNAMICAL MODELS, OFFSET BY
INCONSISTENT AND CONTRADICTORY GUIDANCE FROM FORECAST TOOLS.
FORECASTER: RICH TINKER
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 16.
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:
20031102 - 19861029 - 19861106 - 19851110 - 19571021
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:
20031101 - 19861029 - 19721025 - 19861105 - 19651109
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 02 - 06 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA A A E MONTANA B A WYOMING A A
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA B N S DAKOTA B N
NEBRASKA N N KANSAS N B OKLAHOMA B B
N TEXAS B B S TEXAS B B W TEXAS N B
MINNESOTA B N IOWA N N MISSOURI N B
ARKANSAS B B LOUISIANA B B WISCONSIN B N
ILLINOIS B B MISSISSIPPI B B MICHIGAN B N
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B B NEW YORK B B
VERMONT B B NEW HAMP B B MAINE B B
MASS B B CONN B B RHODE IS B B
PENN B B NEW JERSEY B B W VIRGINIA B B
MARYLAND B B DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B A GEORGIA B N
FL PNHDL B A FL PENIN A A AK N SLOPE A B
AK ALEUTIAN A B AK WESTERN A B AK INT BSN N B
AK S INT A B AK SO COAST A B AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 04 - 10 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF A A
SRN CALIF A N IDAHO A A NEVADA A N
W MONTANA A A E MONTANA B A WYOMING A A
UTAH A N ARIZONA A B COLORADO A N
NEW MEXICO A B N DAKOTA B A S DAKOTA N A
NEBRASKA A N KANSAS A N OKLAHOMA N B
N TEXAS N B S TEXAS A B W TEXAS A B
MINNESOTA B A IOWA N N MISSOURI N N
ARKANSAS N N LOUISIANA N N WISCONSIN B A
ILLINOIS N N MISSISSIPPI N N MICHIGAN B A
INDIANA N N OHIO B A KENTUCKY N N
TENNESSEE N N ALABAMA N N NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N N
FL PNHDL N A FL PENIN A A AK N SLOPE A A
AK ALEUTIAN A N AK WESTERN A N AK INT BSN N A
AK S INT A N AK SO COAST A N AK PNHDL A 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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