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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 WED OCTOBER 25 2023
6-10 DAY OUTLOOK FOR OCT 31 - NOV 04, 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 AS DEPICTED BY 500-HPA HEIGHT ANOMALIES WITH MODERATE
TROUGHING OVER THE NORTH PACIFIC, CONTINUED RIDGING ALONG THE WEST COAST NORTH
OF CALIFORNIA WHICH HAS BEEN SHIFTING NORTHWARD, AND A DEEPENING TROUGH OVER
THE EASTERN CONTIGUOUS U.S. (CONUS) EXTENDING NORTHWARD INTO NORTHEASTERN
CANADA.
THE SYNOPTIC PATTERN IS FAVORABLE FOR AN ARCTIC AIR SURGE MOVING SOUTHWARD OUT
OF CANADA, RESULTING IN BELOW-NORMAL TEMPERATURES BEING FAVORED FOR MUCH OF THE
CONUS. PROBABILITIES ARE HIGHEST OVER PORTIONS OF THE NORTHERN PLAINS AND A
BROAD AREA FROM ROUGHLY SOUTHERN NEW ENGLAND SOUTHWESTWARD ALL THE WAY TO SOUTH
TEXAS (EXCEEDING 70%), AND BELOW-NORMAL TEMPERATURES ARE FAVORED FOR ALMOST THE
ENTIRE CONUS EAST OF THE ROCKIES WITH THE EXCEPTION OF SOUTHERN FLORIDA WHERE
ABOVE-NORMAL TEMPERATURES REMAIN FAVORED. INCREASING ONSHORE FLOW TILTS THE
ODDS TOWARDS ABOVE-NORMAL TEMPERATURES ALONG THE WEST COAST. AMPLIFIED RIDGING
OVER THE WEST COAST AND THE GULF OF ALASKA RESULTS IN SOUTHERLY FLOW ALOFT AND
ENHANCED PROBABILITIES OF ABOVE-NORMAL TEMPERATURES FOR THE ENTIRE STATE.
WEAKLY ABOVE-NORMAL SEA SURFACE TEMPERATURES IN THE HAWAII REGION RESULT IN A
SLIGHT TILT TOWARDS ABOVE-NORMAL TEMPERATURES FOR THE ISLANDS.
WITH SURGING COLD AIR AND THE TROUGH AXIS MOVING EASTWARD, THE 6-10
PRECIPITATION OUTLOOK FOR TODAY IS SIGNIFICANTLY DRIER FOR THE CONUS RELATIVE
TO YESTERDAY. TROPICAL MOISTURE STILL FAVORS ABOVE-NORMAL PRECIPITATION FOR THE
LOWER RIO GRANDE VALLEY AND PORTIONS OF THE SOUTHEASTERN U.S. COAST, BUT
BELOW-NORMAL PRECIPITATION IS NOW FAVORED FOR MOST OF THE CONUS EAST OF THE
ROCKIES. WITH RIDGING OVER THE WEST COAST FAVORED TO DE-AMPLIFY, PREVAILING
FLOW BECOMES MORE ONSHORE AND CHANCES FOR ABOVE-NORMAL PRECIPITATION SPREAD
EASTWARD AND SOUTHWARD RELATIVE TO YESTERDAY, NOW COVERING MUCH OF THE
NORTHWESTERN CONUS. WITH BUILDING POSITIVE HEIGHT ANOMALIES OVER ALASKA,
TILTING THE ODDS IN FAVOR OF BELOW-NORMAL PRECIPITATION FOR MUCH OF THE STATE,
WITH THE EXCEPTION OF THE SOUTHERN MAINLAND WHERE NEAR-NORMAL PRECIPITATION IS
MOST LIKELY. 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 34% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 33% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 33% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
FAIR AGREEMENT AMONG MODELS ON SYNOPTIC PATTERN, OFFSET BY FAST EVOLUTION OF
SYNOPTIC PATTERN AND DIVERGING MODEL SOLUTIONS DURING FORECAST PERIOD.
8-14 DAY OUTLOOK FOR NOV 02 - 08 2023
DYNAMICAL MODELS DEPICT A QUICK TRANSITION FROM THE AMPLIFIED PATTERN SEEN IN
THE 6-10 DAY PERIOD TO A MUCH MORE ZONAL PATTERN BY THE END OF WEEK-2. THIS IS
REFLECTED IN THE 500-HPA HEIGHT ANOMALY MANUAL BLEND FOR TODAY, WHICH DEPICTS
VERY LOW ANOMALIES FOR MOST OF THE CONUS, WITH ONLY WEAK POSITIVE HEIGHT
ANOMALIES OVER THE SOUTHWEST U.S AND THE MID-ATLANTIC. MODEL SOLUTIONS SHIFT
TROUGHING OVER THE NORTH PACIFIC EASTWARD AND TIGHTEN UP THE PRESSURE GRADIENT
ALONG THE WEST COAST.
WITH A DEAMPLIFYING PATTERN OVER NORTH AMERICA DURING WEEK-2, TEMPERATURES FOR
THE CONUS ARE FAVORED TO MODERATE RELATIVE TO THE 6-10 DAY PERIOD. ABOVE-NORMAL
TEMPERATURES ARE INDICATED WEST OF THE ROCKIES, EXTENDING INTO THE CENTRAL
PLAINS, AND ARE ENHANCED ALONG THE COAST AS ONSHORE FLOW INCREASES.
BELOW-NORMAL TEMPERATURES ARE NOW ONLY FAVORED FOR PORTIONS OF THE NORTHERN
PLAINS AND MAINE AS THE ARCTIC AIR FROM THE 6-10 DAY PERIOD IS FORECAST TO
QUICKLY LIFT OUT OF THE CONUS. NEAR-NORMAL TEMPERATURES ARE FAVORED FOR THE
REST OF THE CENTRAL AND EASTERN CONUS, WHILE ABOVE-NORMAL TEMPERATURES REMAIN
MOST LIKELY FOR THE FLORIDA PENINSULA. ABOVE-NORMAL TEMPERATURES ARE ALSO
FAVORED FOR MUCH OF ALASKA, ALTHOUGH WEAKENING SOUTHERLY FLOW RESULTS IN A
REDUCTION IN PROBABILITIES FOR THE ALASKAN INTERIOR AND NEAR-NORMAL
TEMPERATURES FOR THE WESTERN COAST OF ALASKA. WEAKLY ABOVE-NORMAL SEA SURFACE
TEMPERATURES IN THE HAWAII REGION RESULT IN A SLIGHT TILT TOWARDS ABOVE-NORMAL
TEMPERATURES FOR THE ISLANDS.
GUIDANCE FROM DYNAMICAL MODELS AND FORECAST TOOLS INDICATE ENHANCED CHANCES FOR
ABOVE-NORMAL PRECIPITATION FOR MUCH OF THE NORTHWESTERN CONUS WITH IMPROVED
ONSHORE FLOW AND INCREASING AVAILABLE MOISTURE AS DEPICTED BY THE INTEGRATED
VAPOR TRANSPORT TOOL. THERE IS ALSO GOOD AGREEMENT ON LINGERING TROPICAL
MOISTURE TILTING PORTIONS OF THE SOUTHEAST U.S. TOWARDS ABOVE-NORMAL
PRECIPITATION. GOOD CONSENSUS ENDS THERE; THERE ARE CONFLICTING SIGNALS FROM
THE VARIOUS TOOLS PARTICULARLY FOR THE PLAINS AND THE MISSISSIPPI VALLEY. THERE
IS FAIR AGREEMENT ON WEAK ODDS OF BELOW-NORMAL PRECIPITATION FOR PORTIONS OF
THE SOUTHERN PLAINS, BUT OTHERWISE NEAR-NORMAL PRECIPITATION IS FAVORED FOR
MOST OF THE CONUS WITHOUT SUFFICIENT EVIDENCE TO SUPPORT OTHERWISE. AS
SOUTHERLY FLOW OFF THE GULF OF ALASKA SUBSIDES BELOW-NORMAL PRECIPITATION
BECOMES MOST FAVORED FOR ALMOST THE ENTIRE STATE. BELOW-NORMAL PRECIPITATION IS
FAVORED FOR THE HAWAIIAN ISLANDS WITH A CONTINUED DRYING INFLUENCE FROM EL NINO
CONDITIONS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 20% 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 WEAKER
ANOMALIES AND CONTRADICTORY GUIDANCE FROM FORECAST TOOLS.
FORECASTER: DANIEL BARANDIARAN
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:
19861029 - 20031030 - 19591005 - 19721024 - 19901102
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:
19591004 - 19721025 - 20031030 - 19901102 - 19861028
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 31 - NOV 04, 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 N A NEVADA N A
W MONTANA B A E MONTANA B N WYOMING B B
UTAH N N ARIZONA N N COLORADO B B
NEW MEXICO B N N DAKOTA B B S DAKOTA B B
NEBRASKA B B KANSAS B B OKLAHOMA B B
N TEXAS B B S TEXAS B N W TEXAS B B
MINNESOTA B 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 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 B VIRGINIA B B
N CAROLINA B B S CAROLINA B B GEORGIA B B
FL PNHDL B N FL PENIN B A AK N SLOPE A B
AK ALEUTIAN A B AK WESTERN A N AK INT BSN A B
AK S INT A N AK SO COAST A N AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 02 - 08 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 N A WYOMING A A
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA B A S DAKOTA N N
NEBRASKA A N KANSAS A N OKLAHOMA N N
N TEXAS N N S TEXAS N N W TEXAS A N
MINNESOTA N N IOWA N N MISSOURI N N
ARKANSAS N N LOUISIANA N N WISCONSIN N N
ILLINOIS N N MISSISSIPPI N N MICHIGAN N N
INDIANA N N OHIO N N KENTUCKY N N
TENNESSEE N N ALABAMA N N NEW YORK N N
VERMONT N N NEW HAMP N N MAINE B N
MASS N N CONN N N RHODE IS N N
PENN N N NEW JERSEY N N W VIRGINIA N N
MARYLAND N N DELAWARE N N VIRGINIA N N
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN A A AK N SLOPE A B
AK ALEUTIAN A B AK WESTERN A B AK INT BSN A N
AK S INT A B AK SO COAST A B 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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