506
FXUS06 KWBC 152002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST WED JANUARY 15 2025
6-10 DAY OUTLOOK FOR JAN 21 - 25 2025
A HIGHLY AMPLIFIED 500-HPA HEIGHT PATTERN IS FORECAST ACROSS THE FORECAST
DOMAIN DURING THE 6-10 DAY PERIOD, WITH RIDGING OVER WESTERN NORTH AMERICA AND
STRONG TROUGHING DOWNSTREAM EAST OF THE ROCKIES. THIS TROUGHING IS FORECAST TO
LIFT OUT TOWARD THE END OF THE PERIOD, WITH THE 0Z ECENS AND CMCE RELOADING THE
TROUGHING ACROSS THE WEST-CENTRAL CONUS BY DAY-10. THE MANUAL HEIGHT BLEND
INDICATES ABOVE-NORMAL HEIGHTS WEST OF THE ROCKIES AND EXTENDING NORTHWARD
THROUGH ALASKA. A +210 METER POSITIVE HEIGHT ANOMALY CENTER IS DEPICTED JUST TO
THE WEST OF BRITISH COLUMBIA. BELOW NORMAL HEIGHTS ARE PREDICTED FOR MOST OF
THE CONUS EAST OF THE ROCKIES, WITH THE STRONGEST NEGATIVE ANOMALIES (-180
METERS) OVER THE NORTHWEST ATLANTIC. SLIGHTLY ABOVE-NORMAL HEIGHTS ARE FORECAST
ACROSS THE FLORIDA PENINSULA, FURTHER DOWNSTREAM FROM THE MEAN TROUGH AXIS. A
VARIABLE MID-LEVEL HEIGHT PATTERN IS FORECAST ACROSS THE CENTRAL PACIFIC AND
HAWAII, WITH NEAR-NORMAL HEIGHTS FORECAST ACROSS THE ISLANDS FOR THE PERIOD AS
A WHOLE.
A MAJOR ARCTIC AIR OUTBREAK IS FORECAST TO BE ONGOING ACROSS THE CENTRAL AND
EASTERN CONUS AT THE START OF THE PERIOD. THE 0Z ECENS AND GEFS INDICATE
WIDESPREAD DAILY TEMPERATURE ANOMALIES EXCEEDING -20 DEG F ON DAY-6 (JAN 21).
ACTUAL MINIMUM TEMPERATURES RANGE FROM SUBZERO ACROSS PORTIONS OF THE MIDWEST
AND THE INTERIOR NORTHEAST TO IN THE 20S DEG F ALONG THE GULF OF MEXICO COAST.
THE COLD IS FORECAST TO MODERATE AS THE PERIOD PROGRESSES, WITH A FLIP TO
ABOVE-NORMAL TEMPERATURES POSSIBLE ACROSS THE UPPER MIDWEST, BUT TEMPERATURES
REMAINING BELOW-NORMAL OVER MUCH OF THE EAST. THE REFORECAST AND UNCALIBRATED
TOOLS ALL SUPPORT ELEVATED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS
MUCH OF THE CONUS, WITH THE HIGHEST CHANCES (GREATER THAN 80 PERCENT) ACROSS
THE SOUTHERN PLAINS AND MUCH OF THE EAST. NEAR-NORMAL TEMPERATURES ARE FAVORED
ACROSS THE NORTHERN PLAINS DUE TO A QUICKER WARMING TREND AS THE TROUGH LIFTS
OUT. INCREASING DOWNSLOPE WINDS SLIGHTLY FAVOR NEAR- TO ABOVE-NORMAL
TEMPERATURES ACROSS PORTIONS OF CALIFORNIA, SOUTHERN OREGON, AND WESTERN
NEVADA. RIDGING SUPPORTS HIGH CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER
ALASKA. THE CONSOLIDATION FORECAST TOOL SUPPORTS ENHANCED PROBABILITIES FOR
ABOVE-NORMAL TEMPERATURES ACROSS HAWAII, BUT WITH REDUCED PROBABILITIES TO THE
NORTH DUE TO THE POTENTIAL FOR TROUGHING TO DEVELOP OVER THE REGION.
THE AMPLIFIED TROUGH LEADS TO A MORE ACTIVE SOUTHERN STREAM STROM TRACK ACROSS
THE EAST. THEREFORE, THE HIGHEST CHANCES FOR ABOVE-NORMAL PRECIPITATION ARE
HIGHLIGHTED ACROSS THE GULF COAST AND COASTAL SOUTHEAST. HOWEVER, GIVEN THE
COLD AIR IN PLACE, THERE IS SOME CONCERN FOR WINTRY WEATHER OVER SOME OF THESE
AREAS, AND THERE CONTINUE TO BE VARYING OUTCOMES WITHIN THE DETERMINISTIC
MODELS REGARDING THE NORTHWARD PROGRESSION OF SURFACE LOW PRESSURE LATE IN THE
PERIOD. ENHANCED CHANCES FOR BELOW-NORMAL PRECIPITATION ARE FAVORED ACROSS
PARTS OF THE GREAT PLAINS EXTENDING THROUGH THE INTERIOR MID-ATLANTIC AND
NORTHEAST TIED TO STRONG SURFACE HIGH PRESSURE AND ANOMALOUS NORTHERLY
MID-LEVEL FLOW. ELEVATED LAKE EFFECT SNOW CHANCES SLIGHTLY TILT THE ODDS TOWARD
ABOVE-NORMAL PRECIPITATION ACROSS THE NORTHERN GREAT LAKES. ANOMALOUS RIDGING
ACROSS THE WEST SUPPORTS ELEVATED CHANCES FOR BELOW-NORMAL PRECIPITATION FROM
THE ROCKIES TO THE PACIFIC COAST, WITH OCCASIONAL SHORTWAVES MOVING OVERTOP THE
RIDGE AXIS AND ON THE BACKSIDE OF THE DOWNSTREAM TROUGHING LEADING TO ENHANCED
CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS THE NORTHERN HIGH PLAINS.
INCREASED SOUTHERLY FLOW ALONG WITH WEAK TROUGHING OVER THE BERING SEA FAVORS
ELEVATED CHANCES OF ABOVE-NORMAL PRECIPITATION OVER MOST OF ALASKA, WITH THE
HIGHEST CHANCES ACROSS THE NORTHWESTERN MAINLAND DUE TO THE PROJECTED NORTHWARD
SHIFT IN THE STORM TRACK AND REDUCED PRECIPITATION CLIMATOLOGY IN THIS REGION.
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS HAWAII.
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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
VERY GOOD MODEL AGREEMENT REGARDING A MAJOR ARCTIC OUTBREAK ONGOING ACROSS THE
EASTERN HALF OF THE U.S. AT THE START OF THE PERIOD, OFFSET BY A POTENTIAL
MID-LEVEL PATTERN REALIGNMENT BEGINNING LATER IN THE PERIOD, AND UNCERTAINTY
REGARDING THE STORM TRACK IN THE EAST.
8-14 DAY OUTLOOK FOR JAN 23 - 29 2025
THE 500-HPA HEIGHT PATTERN DURING WEEK-2 REMAINS FAIRLY PERSISTENT WITH THAT OF
THE 6-10 DAY PERIOD, WITH SOME DECREASE IN AMPLITUDE IN THE LONGWAVE FEATURES.
THERE CONTINUES TO BE SOME SIGNS OF AN MJO-INDUCED PATTERN CHANGE TOWARD THE
END OF THE PERIOD, WITH THE 0Z ECENS, GEFS, AND CMCE BUILDING POSITIVE HEIGHT
ANOMALIES OVER THE EAST, AND THE LONGWAVE TROUGH RELOADING BUT CENTERED MORE
OVER THE WEST-CENTRAL CONUS. THIS WOULD ALSO BE MORE CONSISTENT WITH THE
BACKGROUND LA NINA STATE. THE MANUAL HEIGHT BLEND FOR WEEK-2 DEPICTS
BELOW-NORMAL HEIGHTS ACROSS MOST OF THE CONUS EAST OF THE ROCKIES, WITH THE
EXCEPTION BEING OVER PARTS OF THE SOUTHEAST AND THE WEST COAST WHERE WEAKLY
ABOVE-NORMAL HEIGHTS ARE INDICATED. ABOVE-NORMAL HEIGHTS CONTINUE TO BE
DEPICTED OVER ALASKA UNDERNEATH RIDGING. NEAR-NORMAL HEIGHTS REMAIN FAVORED FOR
HAWAII DUE TO A VARIABLE HEIGHT PATTERN.
ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES ARE FORECAST ACROSS MOST OF THE
CONUS DURING WEEK-2, ALTHOUGH REGIONAL SWINGS IN TEMPERATURES ARE LIKELY
THROUGHOUT THE PERIOD AS THE MID-LEVEL PATTERN REALIGNS. AT THE START OF THE
PERIOD, THE LARGEST NEGATIVE TEMPERATURE ANOMALIES (-10 DEG F) ARE PREDICTED
OVER THE EASTERN U.S., WITH ABOVE-NORMAL TEMPERATURES MORE LIKELY ACROSS
PORTIONS OF THE NORTHERN PLAINS AND UPPER MIDWEST. THIS MODERATION IS FORECAST
TO SPREAD EASTWARD, AND THE 0Z ECENS AND GEFS DEPICT RELATIVELY WARMER
TEMPERATURES IN THE EAST BY THE END OF WEEK-2 COMPARED TO THE BEGINNING OF THE
PERIOD. HOWEVER, THE RELOADING TROUGH FURTHER WEST FAVORS A RETURN TO COLDER
TEMPERATURES ACROSS THE NORTHERN ROCKIES AND PLAINS LATE IN THE PERIOD
RESULTING IN A FORECAST OF NEAR-NORMAL TEMPERATURES FOR THE PERIOD AS A WHOLE.
THE GEFS AND ECENS REFORECAST TOOLS SUPPORT ENHANCED PROBABILITIES OF
ABOVE-NORMAL TEMPERATURES ACROSS THE SOUTHWEST TIED TO RIDGING AND INCREASING
DOWNSLOPE WINDS, WITH HIGHER PROBABILITIES EXTENDING THROUGH ALASKA. THE
CONSOLIDATION FORECAST TOOL SUPPORTS ENHANCED ODDS FOR ABOVE-NORMAL
TEMPERATURES ACROSS HAWAII.
TROUGHING LIFTING OUT SUPPORTS A MORE NORTHWARD EXTENSION OF INCREASED
ABOVE-NORMAL PRECIPITATION CHANCES IN WEEK-2 ACROSS THE EASTERN CONUS RELATIVE
TO THE PRIOR PERIOD. RECENT DETERMINISTIC MODEL SOLUTIONS DEPICT A WAVE OF
SURFACE LOW PRESSURE BRINGING WINTRY WEATHER TO PARTS OF THE SOUTHEAST AND
POSSIBLY FURTHER NORTH EARLY IN THE PERIOD. ELEVATED PROBABILITIES FOR
ABOVE-NORMAL PRECIPITATION ARE HIGHLIGHTED OVER MOST OF THE GREAT PLAINS,
MIDDLE AND LOWER MISSISSIPPI VALLEY, TENNESSEE VALLEY, AND SOUTHEAST. NEAR- TO
SLIGHTLY BELOW NORMAL PRECIPITATION IS FAVORED OVER PARTS OF THE UPPER MIDWEST
AND NORTHEAST, POTENTIALLY FURTHER DISPLACED FROM THE MEAN STORM TRACK. THE
RETREATING RIDGE OVER WESTERN NORTH AMERICA MAY INCREASE PRECIPITATION CHANCES
ALONG PARTS OF THE WEST COAST BY THE END OF THE PERIOD, WITH NEAR-NORMAL
PRECIPITATION FAVORED FOR THE NORTHWEST AND SLIGHTLY BELOW-NORMAL PRECIPITATION
REMAINING FORECAST OVER THE SOUTHWEST. THE GEFS AND ECENS REFORECAST TOOLS
SUPPORT ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS ALASKA, WITH
ABOVE-NORMAL PRECIPITATION ODDS ALSO REMAINING ELEVATED ACROSS HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 35% 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
MODEL AGREEMENT REGARDING THE EVOLVING MID-LEVEL HEIGHT PATTERN, OFFSET BY
INCREASING TEMPERATURE VARIABILITY WITHIN THE PERIOD AND AN UNCERTAIN STORM
TRACK ALONG THE EAST COAST.
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
JANUARY 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:
19661228 - 19691230 - 20080115 - 19751230 - 19550110
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:
19661228 - 19691230 - 19751231 - 19710105 - 19550109
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 21 - 25 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF A B
SRN CALIF B B IDAHO B B NEVADA N B
W MONTANA B B E MONTANA B A WYOMING B A
UTAH B B ARIZONA B B COLORADO B B
NEW MEXICO B B N DAKOTA N A S DAKOTA B N
NEBRASKA B B KANSAS B B OKLAHOMA B B
N TEXAS B A S TEXAS B A W TEXAS B N
MINNESOTA B A IOWA B B MISSOURI B B
ARKANSAS B B LOUISIANA B A WISCONSIN B B
ILLINOIS B B MISSISSIPPI B A MICHIGAN B N
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA B A NEW YORK B B
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 N DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN B A AK N SLOPE A A
AK ALEUTIAN A A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL A A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 23 - 29 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON N N NRN CALIF A N
SRN CALIF N B IDAHO B N NEVADA A N
W MONTANA B A E MONTANA B A WYOMING B A
UTAH N N ARIZONA N N COLORADO B A
NEW MEXICO B N N DAKOTA N A S DAKOTA N N
NEBRASKA B N KANSAS B A OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA N N IOWA N B MISSOURI B A
ARKANSAS B A LOUISIANA B A WISCONSIN B B
ILLINOIS B N MISSISSIPPI B A MICHIGAN B B
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B A ALABAMA B A 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 N NEW JERSEY B N W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL B A FL PENIN N A AK N SLOPE A A
AK ALEUTIAN A N AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A A AK PNHDL N 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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