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FXUS06 KWBC 212016
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST TUE JANUARY 21 2025
6-10 DAY OUTLOOK FOR JAN 27 - 31 2025
TODAY'S NUMERICAL MODELS DEPICT A COMPLEX 500-HPA FLOW PATTERN ACROSS MUCH OF
THE FORECAST DOMAIN. THE PERIOD BEGINS WITH ANOMALOUS TROUGHING NEAR THE BERING
STRAIT AND STRONG RIDGING FARTHER TO THE SOUTH OVER SOUTHEAST ALASKA AND THE
PACIFIC NORTHWEST. A STRONG TROUGH IS FORECAST OVER THE NORTHEASTERN CONUS AND
A CUTOFF LOW IS DEPICTED OVER SOUTHERN CALIFORNIA. AS TIME PROGRESSES, THE
RIDGE OVER SOUTHEAST ALASKA / PACIFIC NORTHWEST IS FORECAST TO QUICKLY WEAKEN
AS A STRONG TROUGH BUILDS OVER MOST OF ALASKA. THE CUTOFF LOW OVER SOUTHERN
CALIFORNIA IS FORECAST TO WEAKEN AND PROGRESS TOWARD THE SOUTHERN PLAINS BY THE
END OF THE PERIOD. THE STRONG TROUGH OVER THE NORTHEAST IS GENERALLY PREDICTED
TO PROGRESS EASTWARD, ALLOWING HEIGHTS TO RISE IN ITS WAKE OVER PARTS OF THE
CENTRAL CONUS. THE 500-HPA MANUAL HEIGHT BLEND, BASED PRIMARILY ON THE ENSEMBLE
MEANS FROM THE ECMWF, GEFS, AND CANADIAN MODELS, DEPICTS ABOVE NORMAL HEIGHTS
ACROSS THE ALEUTIANS, THE NORTHWESTERN CONUS, AND OVER FLORIDA AND THE GULF
COAST REGION. BELOW NORMAL HEIGHTS ARE FORECAST FOR MOST OF MAINLAND ALASKA,
MOST OF THE GREAT LAKES AND NORTHEAST, AND PARTS OF THE SOUTHWESTERN CONUS.
BELOW NORMAL TEMPERATURES ARE LIKELY ACROSS MUCH OF ALASKA, PARTICULARLY LATER
IN THE PERIOD, AS A TROUGH BUILDS ACROSS THE STATE. PROBABILITIES OF ANOMALOUS
COLD EXCEED 70 PERCENT ACROSS PARTS OF THE WEST COAST OF THE MAINLAND. BELOW
NORMAL TEMPERATURES ARE FAVORED FOR THE CONUS ALONG AND WEST OF THE ROCKIES
DUE, IN PART, TO THE CUTOFF LOW PREDICTED OVER THE SOUTHWESTERN CONUS.
NORTHERLY 500-HPA FLOW ON THE BACKSIDE OF THIS CUTOFF LOW MAY AID IN PROMOTING
BELOW-NORMAL TEMPERATURES ACROSS THESE AREAS. A SLIGHT TILT TOWARD BELOW NORMAL
TEMPERATURES IS INDICATED FOR THE NORTHEAST, AS ANOMALOUS TROUGHING SLOWLY
PROGRESSES THROUGH THE REGION. CONVERSELY, AS THIS TROUGH DEPARTS, HEIGHT RISES
IN ITS WAKE SUPPORT INCREASED PROBABILITIES OF ABOVE NORMAL TEMPERATURES ACROSS
PARTS OF THE NORTH-CENTRAL CONUS. ABOVE NORMAL TEMPERATURES ARE FAVORED FOR
SOUTHERN FLORIDA UNDERNEATH SLIGHTLY POSITIVE MEAN 500-HPA HEIGHTS. A SLIGHT
TILT TOWARD ABOVE NORMAL TEMPERATURES IS ALSO INDICATED FOR PART OF SOUTHEAST
ALASKA DUE TO PREDICTED TRANSIENT RIDGING EARLY IN THE PERIOD. ABOVE NORMAL
TEMPERATURES ARE LIKELY ACROSS HAWAII CONSISTENT WITH ABOVE NORMAL SEA SURFACE
TEMPERATURES IN ADJACENT WATERS.
AS THE PREDICTED TROUGH DEEPENS OVER ALASKA, ENHANCED MOISTURE FLOW AHEAD OF IT
PROMOTES INCREASED CHANCES OF ABOVE-NORMAL PRECIPITATION ACROSS EASTERN PARTS
OF THE STATE, PARTICULARLY FOR SOUTHEAST ALASKA. BELOW NORMAL PRECIPITATION IS
FAVORED FARTHER TO THE SOUTH FROM MUCH OF THE WEST COAST OF THE CONUS EASTWARD
ACROSS THE ROCKIES, NORTHERN AND CENTRAL PLAINS, AND PARTS OF THE MIDWEST AS
THE PREDICTED TRANSIENT RIDGE PROGRESSES EASTWARD. ABOVE NORMAL PRECIPITATION
IS FAVORED FOR MUCH OF THE SOUTHWEST DUE TO THE PREDICTED CUTOFF LOW. THE AREA
OF ENHANCED ABOVE NORMAL PRECIPITATION EXTENDS EAST ACROSS MUCH OF THE SOUTHERN
THIRD OF THE CONUS. PROBABILITIES OF ABOVE NORMAL PRECIPITATION EXCEEDS 40
PERCENT ACROSS THE WESTERN GULF COAST REGION AND THE LOWER MISSISSIPPI VALLEY
DUE TO POTENTIAL RETURN FLOW MOISTURE AROUND PREDICTED HIGH PRESSURE. SLIGHTLY
ENHANCED PROBABILITIES OF ABOVE-NORMAL PRECIPITATION ARE INDICATED FOR PARTS OF
THE NORTHERN GREAT LAKES UNDERNEATH PREDICTED CYCLONIC FLOW. ABOVE NORMAL
PRECIPITATION IS ALSO SLIGHTLY FAVORED FOR HAWAII ASSOCIATED WITH A MEAN TROUGH
FORECAST TO THE WEST OF 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: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY
GOOD AGREEMENT ON AN AMPLIFIED PATTERN EARLY IN THE PERIOD OFFSET BY INCREASED
MODEL SPREAD AS TIME PROGRESSES.
8-14 DAY OUTLOOK FOR JAN 29 - FEB 04, 2025
AFTER OBSERVING A NEGATIVE NAO AND AO FOR MUCH OF THE FIRST HALF OF JANUARY,
MODELS ARE GENERALLY PREDICTING A POSITIVE PHASE OF BOTH INDICES DURING THE
WEEK-TWO PERIOD. THIS POTENTIAL TRANSITION IS ILLUSTRATED BY PREDICTED BELOW
NORMAL HEIGHTS ACROSS MOST OF THE HIGHER LATITUDES OF NORTH AMERICA AND ABOVE
NORMAL HEIGHTS ACROSS MUCH OF THE MID-LATITUDES. THE TRANSITION TO A POSITIVE
AO AND NAO TYPICALLY RESULTS IN A MODERATION OF THE OVERALL FLOW PATTERN AND
LESS ARCTIC AIR INTRUSIONS ACROSS MUCH OF THE CONUS. HOWEVER, WITH ANOMALOUS
RIDGING CONTINUING TO BE FORECAST ACROSS THE HIGHER LATITUDES OF THE EASTERN
HEMISPHERE, THIS MAY ALLOW FOR A MORE SOUTHWARD DISPLACEMENT OF BELOW NORMAL
HEIGHTS THAN TYPICAL WITH A POSITIVE AO AND NAO. THE PERIOD BEGINS WITH STRONG
TROUGHING OVER ALASKA AND THE NORTHEASTERN CONUS. MODELS DISAGREE WITH THE
EVOLUTION OF THE MAIN FEATURES AFTER THAT. THE ECMWF AND GEFS ENSEMBLE MEANS
FORECAST TRANSIENT RIDGING TO QUICKLY PROGRESS EASTWARD ACROSS THE CONUS DURING
THE PERIOD. AS THE OVERALL PATTERN PROGRESSES, MODELS FORECAST MID-LEVEL
TROUGHS TO PENETRATE PARTS OF THE NORTHERN CONUS FROM THE ARCTIC. HOWEVER,
UNCERTAINTY IS VERY HIGH AS TO THE DETAILS OF THESE POTENTIAL ARCTIC INCURSIONS
AT THIS TIME. WITH A POSITIVE NAO AND AO FORECAST, THIS SHOULD LIMIT THE
SOUTHWARD EXTENT OF SUCH INCURSIONS. AS SUCH, THE MEAN 500-HPA HEIGHT BLEND
DEPICTS ABOVE NORMAL HEIGHTS ACROSS MOST OF THE SOUTHERN TWO-THIRDS OF THE
CONUS. BELOW-NORMAL HEIGHTS ARE FORECAST ACROSS NORTHEAST, AND NORTHERN GREAT
LAKES WITH NEAR NORMAL HEIGHTS FAVORED ACROSS THE REMAINDER OF THE NORTHERN
TIER OF THE CONUS. MUCH BELOW-NORMAL HEIGHTS ARE FORECAST FOR SOUTHEASTERN
ALASKA AND ANOMALOUS NORTHERLY MID-LEVEL FLOW IS FORECAST ACROSS MOST OF THE
MAINLAND AND EASTERN ALEUTIANS. ANOMALOUS RIDGING IS PREDICTED FARTHER TO THE
WEST, ACROSS THE WESTERN ALEUTIANS.
A SIGNIFICANT ARCTIC OUTBREAK IS LIKELY FOR MOST OF ALASKA WITH ENHANCED
PROBABILITIES OF BELOW NORMAL TEMPERATURES INDICATED FOR ALMOST THE ENTIRE
STATE WITH THE LONE EXCEPTION BEING THE WESTERN AND CENTRAL ALEUTIANS.
PROBABILITIES OF BELOW NORMAL TEMPERATURES EXCEED 70 PERCENT FOR PARTS OF THE
SOUTHWESTERN MAINLAND NEAR AND BEHIND THE PREDICTED MEAN TROUGH AXIS.
CONFIDENCE IS MUCH LOWER ACROSS THE CONUS DUE TO A PREDICTED TRANSIENT PATTERN.
NEAR TO ABOVE NORMAL TEMPERATURES ARE MODESTLY FAVORED ACROSS MUCH OF THE
CONUS. HOWEVER, DESPITE THE PREDICTED POSITIVE AO AND NAO, PROBABILITY
ANOMALIES ARE MODEST, DUE TO HIGH MODEL SPREAD AND POTENTIAL TRANSIENT
INCURSIONS OF ARCTIC AIR ALONG THE NORTHERN TIER. A TILT TOWARD BELOW NORMAL
TEMPERATURES ARE INDICATED FOR THE NORTHEAST, DUE TO PREDICTED MEAN TROUGHING
AND BELOW NORMAL HEIGHTS, AS WELL AS FOR PARTS OF THE NORTHWESTERN CONUS AS THE
ALASKA TROUGH PROGRESSES EASTWARD. A SLIGHT TILT TOWARD BELOW NORMAL
TEMPERATURES IS INDICATED FOR SOUTHERN CALIFORNIA DUE TO POTENTIAL RESIDUAL
EFFECTS FROM THE CUTOFF LOW FORECAST EARLY IN THE PERIOD. CONVERSELY, ABOVE
NORMAL TEMPERATURES ARE LIKELY FOR HAWAII, DUE, IN PART, TO ABOVE NORMAL SSTS
IN ADJACENT WATERS.
AS A DEEP TROUGH PROGRESSES ACROSS ALASKA, A DRYING TREND IS ANTICIPATED ACROSS
THE WESTERN MAINLAND UNDERNEATH NORTHERLY FLOW, SUPPORTING ENHANCED CHANCES OF
BELOW NORMAL PRECIPITATION. ABOVE NORMAL PRECIPITATION IS FAVORED FOR
SOUTHEASTERN ALASKA, AHEAD OF THE TROUGH AXIS. AS THE TROUGH PROGRESSES
SOUTHEASTWARD, INCREASED ONSHORE FLOW IS LIKELY TO SHIFT FARTHER TO THE SOUTH
ACROSS THE WEST COAST OF NORTH AMERICA. THIS POTENTIAL SOUTHWARD SHIFT
INCREASES PROBABILITIES OF ABOVE NORMAL PRECIPITATION ACROSS THE NORTHWESTERN
CONUS. A SLIGHT TILT TOWARD ABOVE NORMAL PRECIPITATION IS INDICATED EASTWARD
ACROSS THE NORTHERN TIER, NEAR A POTENTIAL MEAN BAROCLINIC ZONE CLOSE TO THE
CONUS/CANADA BORDER. INCREASED CHANCES OF ABOVE-NORMAL PRECIPITATION IS ALSO
INDICATED FROM THE WESTERN GULF COAST REGION, NORTHEASTWARD ACROSS THE LOWER
MISSISSIPPI VALLEY, TENNESSEE VALLEY, SOUTHERN OHIO VALLEY, AND PARTS OF THE
SOUTHERN AND CENTRAL APPALACHIANS DUE TO POTENTIAL MOISTURE ADVECTION AROUND
THE BACKSIDE OF PREDICTED SURFACE HIGH PRESSURE. A SLIGHT TILT TOWARD BELOW
NORMAL PRECIPITATION IS INDICATED FOR THE SOUTHERN FLORIDA PENINSULA CLOSER TO
THE PREDICTED SURFACE HIGH PRESSURE. CONVERSELY, A SLIGHT TILT TOWARD ABOVE
NORMAL PRECIPITATION IS INDICATED FOR HAWAII, DUE TO A PREDICTED TROUGH IN THE
VICINITY.
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, DUE TO
MODEL DISAGREEMENTS ON THE EVOLUTION OF A PREDICTED TRANSITIONAL PATTERN ACROSS
MUCH OF THE FORECAST DOMAIN.
FORECASTER: SCOTT H
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
FEBRUARY 20.
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:
20080120 - 19910122 - 19940201 - 19680102 - 19810203
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:
19940131 - 19671231 - 20080119 - 19620110 - 19810203
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 27 - 31 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON B B NRN CALIF B B
SRN CALIF B N IDAHO B B NEVADA B B
W MONTANA B B E MONTANA A B WYOMING B B
UTAH B B ARIZONA B A COLORADO B B
NEW MEXICO B A N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS N B OKLAHOMA N A
N TEXAS N A S TEXAS N A W TEXAS B A
MINNESOTA A B IOWA A B MISSOURI N B
ARKANSAS N A LOUISIANA N A WISCONSIN A N
ILLINOIS N B MISSISSIPPI N A MICHIGAN N N
INDIANA N B OHIO N N KENTUCKY N N
TENNESSEE N A ALABAMA N 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 N N
MARYLAND B N DELAWARE B N VIRGINIA N N
N CAROLINA N A S CAROLINA N A GEORGIA N A
FL PNHDL N A FL PENIN A N AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 29 - FEB 04, 2025
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N A NRN CALIF N B
SRN CALIF B B IDAHO N A NEVADA A B
W MONTANA N A E MONTANA N A WYOMING N N
UTAH A B ARIZONA N B COLORADO N B
NEW MEXICO N B N DAKOTA N A S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A A LOUISIANA A A WISCONSIN N N
ILLINOIS N N MISSISSIPPI A A MICHIGAN N A
INDIANA N N OHIO N N KENTUCKY N A
TENNESSEE N A ALABAMA N A NEW YORK B N
VERMONT B N NEW HAMP B N MAINE B A
MASS B N CONN B N RHODE IS B N
PENN N N NEW JERSEY B N W VIRGINIA N A
MARYLAND N N DELAWARE N N VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA N N
FL PNHDL A N FL PENIN A B AK N SLOPE B N
AK ALEUTIAN B N AK WESTERN B B AK INT BSN B N
AK S INT B N AK SO COAST B N AK PNHDL B 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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