104
FXUS06 KWBC 022002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST THU JANUARY 02 2025
6-10 DAY OUTLOOK FOR JAN 08 - 12 2025
THE GEFS, ECENS, AND CMCE ARE IN GOOD AGREEMENT AND REMAIN CONSISTENT THAT HIGH
LATITUDE BLOCKING PERSISTS THROUGH EARLY JANUARY AFTER A PAIR OF STRONG 500-HPA
RIDGES OVER GREENLAND AND NEAR THE WEST COAST OF NORTH AMERICA MERGE. THE GEFS
DEPICTS A NEGATIVE ARCTIC OSCILLATION (AO) PEAKING IN STRENGTH AT NEAR -4
STANDARD DEVIATIONS BY THE BEGINNING OF THIS PERIOD. THE HIGH LATITUDE BLOCKING
IS LIKELY TO PROMOTE ARCTIC HIGH PRESSURE SHIFTING SOUTH PRIOR TO JANUARY 8.
ANOMALOUSLY COLD TEMPERATURES, ASSOCIATED WITH THE ARCTIC HIGH, SUPPORT
BELOW-NORMAL TEMPERATURES ACROSS MOST OF THE EASTERN AND CENTRAL CONTIGUOUS
U.S. (CONUS). LARGE BELOW-NORMAL TEMPERATURE PROBABILITIES (MORE THAN 80
PERCENT) ARE FORECAST FROM THE LOWER AND MIDDLE MISSISSIPPI VALLEY EASTWARD TO
THE SOUTHEAST AND MID-ATLANTIC WHERE THE ENSEMBLE MEAN SOLUTIONS HAVE 5-DAY
TEMPERATURES AVERAGING 10 TO 20 DEGREES F BELOW NORMAL. PRIOR TO THE 6-10 DAY
PERIOD, A SWATH OF SNOWFALL IS FORECAST FROM THE MIDDLE MISSISSIPPI VALLEY EAST
TO THE OHIO VALLEY AND MID-ATLANTIC WHICH WILL FURTHER SUPPORT THE CHANCE FOR
ANOMALOUS COLD. SIMILAR TO YESTERDAY, THE ENSEMBLE MEAN SOLUTIONS FAVOR A
MODERATING TREND ACROSS THE NORTH-CENTRAL CONUS ON DAY 8 AND THE UNCALIBRATED
ECENS FLIPS TEMPERATURES TO ABOVE-NORMAL FOR THE NORTHERN PLAINS ON DAYS 9 AND
10. THEREFORE, THERE IS A TIGHT GRADIENT BETWEEN FAVORED BELOW- AND
ABOVE-NORMAL TEMPERATURES FROM THE GREAT LAKES WEST TO THE WESTERN DAKOTAS. AN
AMPLIFIED 500-HPA RIDGE AND POSITIVE HEIGHT DEPARTURES SUPPORT INCREASED
ABOVE-NORMAL TEMPERATURES ACROSS THE PACIFIC NORTHWEST, CALIFORNIA, GREAT
BASIN, DESERT SOUTHWEST, AND NORTHERN TO CENTRAL ROCKIES.
ANOMALOUS NORTHERLY FLOW FAVORS NEAR TO BELOW-NORMAL PRECIPITATION FOR MOST
AREAS FROM THE MIDDLE AND LOWER MISSISSIPPI VALLEY TO THE EAST COAST. NEAR
NORMAL PRECIPITATION REMAINS FAVORED DOWNWIND OF THE GREAT LAKES DUE TO
LAKE-EFFECT SNOW. MODEL GUIDANCE, ESPECIALLY THE DETERMINISTIC 0Z ECMWF MODEL,
DEPICTS A SHORTWAVE TROUGH BECOMING DETACHED FROM THE MID-LATITUDE FLOW WHICH
LEADS TO A CUT-OFF 500-HPA LOW FORMING OVER THE BAJA PENINSULA ON DAYS 6 AND 7.
THE INTERACTION BETWEEN THIS CUT-OFF 500-HPA LOW AND SHORTWAVE TROUGHS WITHIN
THE NORTHERN STREAM PROVIDES HIGH UNCERTAINTY ON WHEN AND WHERE SURFACE LOW
DEVELOPMENT OCCURS DOWNSTREAM NEAR THE GULF COAST. THE LATEST MODEL CONSENSUS
FAVORS AN INITIAL WAVE OF LOW PRESSURE OVER THE WESTERN GULF OF MEXICO ON DAY 6
WITH A SUPPRESSED TRACK TO THE FLORIDA PENINSULA. AS A RESULT, ELEVATED
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE LIMITED TO THE RIO GRANDE VALLEY,
SOUTH TEXAS, AND CENTRAL TO SOUTH FLORIDA. INCREASED ABOVE-NORMAL PROBABILITIES
FOR THE NORTHERN TO CENTRAL ROCKIES, NORTHERN TO CENTRAL GREAT PLAINS, AND
UPPER MISSISSIPPI VALLEY ARE RELATED TO A SHORTWAVE TROUGH IN THE NORTHERN
STREAM. AN AMPLIFIED 500-HPA RIDGE NEAR THE WEST COAST LEADS TO AN INCREASED
CHANCE OF BELOW-NORMAL PRECIPITATION ACROSS THE PACIFIC NORTHWEST, GREAT BASIN,
CALIFORNIA, AND THE SOUTHWEST.
ENSEMBLE MEAN SOLUTIONS ARE IN GOOD AGREEMENT FEATURING AN AMPLIFIED 500-HPA
TROUGH (RIDGE) OVER THE ALEUTIANS (EASTERN MAINLAND ALASKA). THIS LONGWAVE
PATTERN YIELDS INCREASED ABOVE-NORMAL TEMPERATURE PROBABILITIES FOR A MAJORITY
OF ALASKA. NEAR TO BELOW-NORMAL TEMPERATURES ARE FAVORED ACROSS NORTHWESTERN
ALASKA DUE TO NEARBY ARCTIC HIGH PRESSURE. ENHANCED ONSHORE FLOW FAVORS
ABOVE-NORMAL PRECIPITATION FOR ALASKA WITH THE HIGHEST FORECAST CONFIDENCE
ACROSS THE SOUTHERN THIRD OF THE STATE.
BASED ON THE GEFS AND ECENS, ABOVE-NORMAL TEMPERATURES ARE STRONGLY FAVORED FOR
HAWAII. THE CONSOLIDATION SUPPORTS RELATIVELY LARGE ABOVE-NORMAL PRECIPITATION
PROBABILITIES FOR THE STATE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 30% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% 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
A HIGHLY AMPLIFIED LONGWAVE PATTERN AND GOOD AGREEMENT AMONG THE TEMPERATURE
AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR JAN 10 - 16 2025
A HIGHLY AMPLIFIED 500-HPA TROUGH IS FORECAST TO PERSIST OVER THE EASTERN CONUS
AND WESTERN ATLANTIC, WHILE THE HIGH LATITUDE BLOCK ACROSS SOUTHERN GREENLAND
AND THE DAVIS STRAIT GRADUALLY WEAKENS. THE ANOMALOUS MID-LEVEL TROUGH AND
NORTHERLY FLOW FAVOR COLDER-THAN-NORMAL TEMPERATURES ACROSS MUCH OF THE EASTERN
AND SOUTH-CENTRAL CONUS. THE LARGEST PROBABILITIES (MORE THAN 70 PERCENT) ARE
FORECAST FROM THE OHIO VALLEY AND MID-ATLANTIC SOUTH TO FLORIDA WHERE THE GEFS
AND ECENS FEATURE 7-DAY TEMPERATURES AVERAGING NEAR OR MORE THAN 10 DEGREES F
BELOW NORMAL. FOR THE SECOND CONSECUTIVE DAY, THE GEFS, ECENS, AND CMCE VARY
WITH THE AMPLITUDE AND PLACEMENT OF THE 500-HPA RIDGE AXIS NEAR THE WEST COAST.
LATER IN WEEK-2, THE ECENS DEPICTS A BUILDING RIDGE CLOSER TO THE ALEUTIANS
WHILE THE CMCE MAINTAINS A HIGH AMPLITUDE RIDGE ALONG THE WEST COAST. THESE
INCREASING MODEL DIFFERENCES ON THE LONGWAVE PATTERN ACROSS THE NORTH PACIFIC
AND WESTERN NORTH AMERICA REDUCE FORECAST CONFIDENCE BY MID-JANUARY. NEAR
NORMAL TEMPERATURES ARE FORECAST FOR MUCH OF THE DAKOTAS AND NORTHERN MINNESOTA
SINCE TEMPERATURES ARE EXPECTED TO BE QUITE VARIABLE DURING THIS 7-DAY TIME
PERIOD. BASED ON THE UNCALIBRATED MODEL GUIDANCE AND THE ANALOG TOOL DERIVED
FROM THE 500-HPA HEIGHT BLEND, ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE LOWER
FOR THE WESTERN CONUS COMPARED TO YESTERDAY AND NEAR-NORMAL TEMPERATURES ARE
FAVORED FOR PORTIONS OF THE NORTH-CENTRAL ROCKIES.
THE WEEK-2 PRECIPITATION OUTLOOK CONTINUES TO LEAN ON THE DRIER SIDE FOR MUCH
OF THE CENTRAL AND EASTERN CONUS DUE TO PREVAILING NORTHERLY SURFACE FLOW.
HOWEVER, TWO WAVES OF LOW PRESSURE (DAY 8 AND 11-12) ARE EXPECTED TO DEVELOP
NEAR THE GULF COAST. THE GEFS AND ECENS DEPICT THE INITIAL LOW PRESSURE SYSTEM
SUPPRESSED TO THE SOUTH OVER THE GULF OF MEXICO, BUT THE SECOND ONE HAS A
BETTER CHANCE OF TAKING A MORE NORTHERLY TRACK TO THE SOUTHEAST AND SOUTHERN
MID-ATLANTIC AFTER THE GREENLAND BLOCK WEAKENS. NEW ENGLAND AND THE LOWER OHIO
VALLEY HAVE THE LARGEST BELOW-NORMAL PRECIPITATION PROBABILITIES SINCE THESE
AREAS ARE LIKELY TO REMAIN OUTSIDE OF ANY STORM TRACK. SHORTWAVE TROUGHS WITHIN
THE NORTHERN STREAM FAVOR ABOVE-NORMAL PRECIPITATION ACROSS THE NORTHERN AND
CENTRAL ROCKIES EAST TO THE NORTHERN GREAT PLAINS. ALONG THE TAIL END OF A
FRONT, ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED FROM THE SOUTHERN HIGH
PLAINS SOUTHWARD TO THE RIO GRANDE VALLEY. BELOW-NORMAL PRECIPITATION REMAINS
FAVORED FOR THE WESTERN CONUS WITH THE ABSENCE OF ANY ONSHORE FLOW, BUT
PROBABILITIES ARE LOWER TODAY AS MODEL SOLUTIONS DIFFER ON THE 500-HPA RIDGE
PLACEMENT/STRENGTH NEAR OR OFFSHORE OF THE WEST COAST.
DOWNSTREAM OF A BROAD TROUGH OVER THE BERING SEA, ABOVE-NORMAL PRECIPITATION IS
FAVORED FOR ALASKA. CONSISTENT WITH THIS WETNESS AND ENHANCED ONSHORE FLOW,
INCREASED ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE FORECAST ACROSS MUCH OF
ALASKA. SIMILAR TO THE 6-10 DAY OUTLOOK, NEARBY ARCTIC HIGH PRESSURE FAVORS
NEAR TO BELOW-NORMAL TEMPERATURES FOR NORTHERN ALASKA.
BASED ON THE GEFS AND ECENS, INCREASED CHANCES OF ABOVE-NORMAL TEMPERATURES AND
ABOVE-NORMAL PRECIPITATION ARE FORECAST FOR HAWAII.
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 HIGH
FORECAST CONFIDENCE IN THE TEMPERATURE OUTLOOK ACROSS THE EASTERN CONUS OFFSET
BY MORE UNCERTAINTY IN THE TEMPERATURE OUTLOOK FOR THE NORTH-CENTRAL CONUS
ALONG WITH THE PRECIPITATION OUTLOOK THROUGHOUT THE CENTRAL AND EASTERN CONUS.
FORECASTER: BRAD PUGH
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:
20091224 - 20001222 - 19811213 - 19661223 - 19781229
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:
20091223 - 20001223 - 19811212 - 20091229 - 19961214
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 08 - 12 2025
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 A E MONTANA A A WYOMING A A
UTAH A B ARIZONA A B COLORADO N A
NEW MEXICO B N N DAKOTA A A S DAKOTA B A
NEBRASKA B A KANSAS B N OKLAHOMA B B
N TEXAS B B S TEXAS B A W TEXAS B N
MINNESOTA B A IOWA B N MISSOURI B B
ARKANSAS B B LOUISIANA B B WISCONSIN B N
ILLINOIS B N 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 N 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 B 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 10 - 16 2025
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 N E MONTANA A A WYOMING N A
UTAH A B ARIZONA A B COLORADO N A
NEW MEXICO N A N DAKOTA N A S DAKOTA N A
NEBRASKA B A KANSAS B N OKLAHOMA B B
N TEXAS B N S TEXAS B A W TEXAS B N
MINNESOTA N N IOWA B N MISSOURI B B
ARKANSAS B B LOUISIANA B N 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 N NEW JERSEY B B W VIRGINIA B N
MARYLAND B B DELAWARE B B VIRGINIA B B
N CAROLINA B B S CAROLINA B N GEORGIA B N
FL PNHDL B N FL PENIN B N AK N SLOPE N 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
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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