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FXUS06 KWBC 192032
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST MON FEBRUARY 19 2024
6-10 DAY OUTLOOK FOR FEB 25 - 29 2024
MODELS ARE IN FAIR AGREEMENT ON THE MEAN PLACEMENT OF THE LARGE-SCALE MID-LEVEL
FEATURES, BUT THE DETAILS ON THE EVOLUTION OF THE PATTERN AND ON THE STRENGTH
AND PLACEMENT OF INDIVIDUAL SYSTEMS ARE LESS CLEAR. MOST TOOLS CENTER A MEAN
NEGATIVE 500-HPA HEIGHT ANOMALY SOMEWHERE NEAR SOUTH-CENTRAL OR SOUTHEASTERN
ALASKA, WITH NEGATIVE HEIGHT ANOMALIES COVERING VIRTUALLY ALL OF THE STATE.
DOWNSTREAM, MODELS GENERALLY AGREE THAT NEGATIVE HEIGHT ANOMALIES WILL EXTEND
SOUTHWARD THROUGH WESTERN PARTS OF CANADA AND THE CONTIGUOUS UNITED STATES
(CONUS) WITH POSITIVE HEIGHT ANOMALIES FARTHER EAST, GENERALLY ACROSS THE LOWER
MISSISSIPPI VALLEY AND MOST OF THE EASTERN CONUS. MODELS ALSO CENTER A POSITIVE
500-HPA HEIGHT ANOMALY OVER THE CENTRAL NORTH ATLANTIC OCEAN.
REGARDING UNCERTAINTIES, ONE OF THE MAJOR SITUATIONS IS OVER THE WESTERN CONUS,
AND IMPACTS THE PRECIPITATION FORECAST FOR THAT REGION. ENSEMBLE MEANS ALL
PAINT NEGATIVE 500-HPA ANOMALIES OVER MANY AREAS FROM THE ROCKIES WESTWARD, BUT
IN TERMS OF HOW CONDITIONS EVOLVE DAY-BY-DAY, THE EUROPEAN ENSEMBLE MEAN
RELOADS A STRONG MID-LEVEL TROUGH JUST OFF THE NORTHWESTERN CONUS COAST AFTER
ONE SYSTEM MOVES INLAND TOWARD THE INTERMOUNTAIN WEST. IN CONTRAST, THE GEFS
TAKES A SOMEWHAT MORE COHERENT SYSTEM PROGRESSIVELY INTO THE WESTERN AND
CENTRAL CONUS, SHOWING MORE RETROGRADE FARTHER WEST WITH A MID-LEVEL TROUGH
RE-ESTABLISHING ITSELF WELL WEST OF THE EUROPEAN ENSEMBLE MEAN, OVER THE
NORTH-CENTRAL NORTH PACIFIC. THE EUROPEAN ENSEMBLE MEAN KEEPS CYCLONIC
MID-LEVEL FLOW OVER THE REGION FOR MOST OF THE PERIOD, WHEREAS THE GEFS BUILDS
A TEMPORARY MID-LEVEL RIDGE INTO WESTERN NORTH AMERICA, ALLOWING FOR A PERIOD
OF DRIER WEATHER IN THE WESTERN CONUS. THE CANADIAN ENSEMBLE MEAN HAS A
SOMEWHAT DIFFERENT EVOLUTION THAN EITHER OF THE OTHER ENSEMBLE MEANS, BUT THE
RESULTANT PRECIPITATION OUTPUT LOOKS MORE LIKE THE EUROPEAN ENSEMBLE MEAN THAN
THE GEFS MEAN. REFORECAST TOOLS SHARPEN THE DIFFERENCE BETWEEN THE GEFS AND THE
EUROPEAN ENSEMBLE, INCREASING WET SIGNAL IN THE EUROPEAN ENSEMBLE BUT REDUCING
ODDS FOR ABOVE-NORMAL PRECIPITATION IN THE GEFS. IN THE END, THE OFFICIAL LEANS
TOWARD A WETTER SOLUTION SOMEWHAT, BUT IS SUBSTANTIALLY DRIER THAN THE EUROPEAN
ENSEMBLE REFORECAST.
ELSEWHERE, PRECIPITATION FORECAST TOOLS ARE MORE SIMILAR, AND THE OFFICIAL
FORECAST IS A BLEND OF THESE SOLUTIONS, FAVORING ABOVE-NORMAL PRECIPITATION
OVER THE ROCKIES, INTERMOUNTAIN WEST, OHIO VALLEY, UPPER SOUTH, AND NORTHEAST
WHILE DRIER THAN NORMAL CONDITIONS ARE FAVORED IN THE SOUTHERN GREAT PLAINS AND
FLORIDA PENINSULA.
THERE ARE ALSO SIGNIFICANT DISCREPANCIES IN THE 500-HPA HEIGHTS OVER
NORTHEASTERN NORTH AMERICA. THE GEFS AND CANADIAN ENSEMBLES AND THE 6Z
OPERATIONAL GFS FAVOR AT LEAST SLIGHTLY BELOW-NORMAL HEIGHTS CENTERED OVER
EAST-CENTRAL CANADA, WITH NEAR- OR BELOW-NORMAL HEIGHTS EXTENDING SOUTHWARD
INTO NORTHERN NEW ENGLAND. MEANWHILE, THE EUROPEAN ENSEMBLE AND OPERATIONAL
EUROPEAN MODELS PLACE A POSITIVE 500-HPA HEIGHT ANOMALY OVER NEW ENGLAND, WITH
LESSER POSITIVE ANOMALIES FARTHER SOUTH. TELECONNECTIONS TO THE TROUGH CENTERED
NEAR SOUTHEASTERN ALASKA TEND TO FAVOR WEAKER POSITIVE ANOMALIES OR NEAR-NORMAL
500-HPA HEIGHTS OVER THE NORTHEASTERN CONUS, WITH A SLIGHTLY MORE ROBUST SIGNAL
FARTHER SOUTH AND WEST.
THESE DIFFERENCES MAY IMPACT THE EVOLUTION OF THE MID-LEVEL PATTERN LATER
WEEK-2 AND BEYOND, EVENTUALLY HAVING AN IMPACT ON THE ARCTIC OSCILLATION, BUT
FOR THIS PERIOD, BOTH FAVOR WARMER-THAN-NORMAL THROUGHOUT THE CONUS EAST OF THE
ROCKIES, WITH ODDS EXCEEDING 80 PERCENT ACROSS A LARGE AREA FROM THE EASTERN
GREAT PLAINS AND THE MISSISSIPPI VALLEY EASTWARD INTO THE INTERIOR SOUTHEAST
AND MID-ATLANTIC REGION. IN THE WEST, MOST TOOLS SOMEWHAT FAVOR SUBNORMAL
TEMPERATURES, BUT THE REFORECAST TOOLS FOR ALL ENSEMBLES ARE CONSIDERABLY
MILDER. THE FORECAST LEANS TOWARD THE PREPONDERANCE OF TOOLS, WHICH LEAN TOWARD
BELOW-NORMAL TEMPERATURES.
WITH BELOW-NORMAL 500-HPA HEIGHTS DOMINATING ALASKA AND A MEAN SURFACE LOW
PRESSURE SYSTEM SOMEWHERE NEAR THE SOUTH-CENTRAL OR SOUTHEASTERN PACIFIC
COASTLINE, BELOW-NORMAL TEMPERATURES ARE OVERWHELMINGLY FAVORED ACROSS MOST OF
THE STATE, WITH THE BEST ODDS (OVER 80 PERCENT) ACROSS THE SOUTHERN HALF OF THE
MAINLAND. THERE IS MORE UNCERTAINTY IN SOUTHEASTERN ALASKA, WHERE MILD SURFACE
FLOW FROM THE SOUTH (EAST OF THE MEAN SURFACE LOW POSITION) COULD BRING IN
MILDER AIR. ABOVE-NORMAL PRECIPITATION IS ALSO FAVORED IN THIS LOCATION, BUT
MOST OF ALASKA - BEING NEAR OR UPSTREAM FROM THE MEAN MID-LEVEL TROUGH POSITION
- HAVE A BETTER CHANCE OF BEING DRIER THAN NORMAL.
WARMER AND WETTER THAN NORMAL CONDITIONS ARE FAVORED ACROSS HAWAII, UPSTREAM
FROM A MID-LEVEL TROUGH AND SURROUNDED BY ABOVE-NORMAL SEA SURFACE TEMPERATURES.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 60% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 8, 25% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 15% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT NORMAL, 3 OUT OF 5, WITH
UNCERTAINTIES IN THE EVOLUTION OF FEATURES OFFSET BY BETTER AGREEMENT ON THE
MEAN PATTERN AND THE DERIVED TEMPERATURE AND PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR FEB 27 - MAR 04, 2024
THE DIFFERENCES IN THE MODELS DURING THE 6- TO 10-DAY PERIOD EXTRAPOLATE INTO
WEEK-2, WITH FAIR AGREEMENT ON THE LARGE-SCALE MEAN PATTERN BUT DIFFERENCES IN
THE EVOLUTION OF INDIVIDUAL FEATURES. A FAIRLY STRONG MID-LEVEL RIDGE IS
CENTERED SOUTH OF THE ALEUTIANS WHILE A MID-LEVEL TROUGH WITH SUBNORMAL 500-HPA
HEIGHTS HAS AN AXIS THROUGH EASTERN MAINLAND ALASKA WITH A NEGATIVE 500-HPA
HEIGHT ANOMALY CENTER CENTERED JUST SOUTH OF THE SOUTHEASTERN ALASKA COAST. THE
NEGATIVE 500-HPA HEIGHTS EXTEND SOUTHWARD INTO THE WESTERN CONUS AS FAR SOUTH
AND EAST AS THE EAST-CENTRAL ROCKIES. MEANWHILE, THE POSITIVE 500-HPA ANOMALY
CENTER MOVES FARTHER NORTH INTO THE NORTHEASTERN CONUS, BUT ABOVE-NORMAL
HEIGHTS PERSIST THROUGHOUT THE EAST AND SOUTHWESTWARD TOWARD THE SOUTHERN
ROCKIES.
THE EVOLUTION OF INDIVIDUAL FEATURES FROM THE NORTH PACIFIC INTO THE WESTERN
CONUS IS VERY UNCERTAIN DURING THIS PERIOD, WITH THE EUROPEAN ENSEMBLES AND ITS
DERIVED TOOLS REMAINING CONSIDERABLY WETTER THAN THE GEFS TOOLS THERE. HOWEVER,
ALL MODELS SHOW BELOW-NORMAL MID-LEVEL HEIGHTS OVER THE WEST NORTH OF THE
DESERTS, WITH MEAN SURFACE LOW PRESSURE NEAR SOUTHEASTERN ALASKA RESULTING IN
FREQUENT ONSHORE FLOW. THUS, ALTHOUGH THE TIMING AND INTENSITY OF PRECIPITATION
DIFFER AMONG THE TOOLS, MOST SIGNS POINT TOWARD MORE PRECIPITATION THAN NORMAL
FOR MUCH OF THE WEST, AND THIS IS FAVORED IN THE FORECAST. THE EXCEPTION IS IN
THE SOUTHERN TIER OF THIS REGION, WHERE INCREASED MEAN MID-LEVEL HEIGHTS RESULT
FROM MID-LEVEL TROUGHS AND STORMINESS PRIMARILY AFFECTING AREAS FARTHER NORTH,
RESULTING IN A SLIGHT TILT OF THE ODDS TOWARD SUBNORMAL PRECIPITATION ACROSS
THE SOUTHERN TIER OF THE WEST.
FARTHER EAST, THE SURFACE AND MID-LEVEL PATTERNS FAVOR BELOW-NORMAL
PRECIPITATION ACROSS THE SOUTHERN ROCKIES AND PLAINS AS WELL, WITH ACTIVE
FEATURES PASSING TO THE NORTH. FROM THE CENTRAL AND NORTHERN ROCKIES EASTWARD,
CYCLONIC MID-LEVEL FROW FROM THE MEAN TROUGH NEAR THE WEST COAST TO THE HIGHER
MID-LEVEL HEIGHTS FARTHER EAST SOMEWHAT FAVORS ABOVE-NORMAL PRECIPITATION,
PARTICULARLY FROM THE OHIO VALLEY TO THE NORTH AND EAST WHERE SOUTHERLY SURFACE
FLOW FROM THE GULF OF MEXICO WILL OVERRUN A QUASI-STATIONARY FRONTAL SYSTEM
THERE.
THERE REMAINS A STRONG TILT TOWARD ABOVE-NORMAL TEMPERATURES EAST OF THE
ROCKIES, WITH ODDS EXCEEDING 70 PERCENT FROM THE MIDDLE AND UPPER MISSISSIPPI
VALLEY EASTWARD INTO THE EASTERN CONUS. ONCE AGAIN, RAW AND BIAS-CORRECTED
OUTPUT FROM THE ENSEMBLE MEANS FAVOR COLDER THAN NORMAL CONDITIONS FROM THE
ROCKIES WESTWARD WHILE THE REFORECAST PRODUCTS SHOW MILDER CONDITIONS. THE
PREPONDERANCE OF THE EVIDENCE IMPLIES COOLER THAN NORMAL CONDITIONS IN THE
WEST, AND THAT IS REFLECTED IN THE FORECAST.
THE STRONG MID-LEVEL TROUGH NEAR ALASKA AND BELOW-NORMAL 500-HPA HEIGHTS
STATEWIDE CONTINUE TO HEAVILY FAVOR COLDER THAN NORMAL WEATHER THROUGHOUT
WEEK-2, WITH ODDS EXCEEDING 80 PERCENT ACROSS THE SOUTHERN HALF OF THE
MAINLAND. CHANCES FOR COOLER THAN NORMAL CONDITIONS ARE LESS ROBUST OVER
SOUTHEASTERN ALASKA, WHERE SOUTHERLY SURFACE FLOW TO THE EAST OF MEAN SURFACE
LOW PRESSURE WILL AT LEAST OCCASIONALLY DISPLACE ARCTIC AIR FROM THE NORTH.
THIS LATTER REGION IS ALSO EXPECTED TO BE WETTER THAN NORMAL, BEING EAST OF THE
MEAN SURFACE LOW PRESSURE AND MID-LEVEL TROUGH LOCATIONS WHILE MOST OTHER PARTS
OF THE STATE ARE EXPECTED TO BE DRIER THAN NORMAL NEAR AND WEST OF THE TROUGH
AXIS.
HAWAII IS EXPECTED TO REMAIN UPSTREAM FROM A MID-LEVEL TROUGH IN AN AREA OF
ABOVE-NORMAL SEA SURFACE TEMPERATURES, SO WARMER- AND WETTER-THAN-NORMAL
CONDITIONS ARE FAVORED TO PERSIST THROUGH WEEK-2.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 55% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 15% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: NEAR NORMAL, 3 OUT OF 5, WITH
SIGNIFICANT DIFFERENCES IN THE EVOLUTION OF INDIVIDUAL FEATURES TEMPERED BY
BETTER AGREEMENT IN THE MEAN POSITION OF 500-HPA ANOMALIES AND MODEL-DERIVED
TEMPERATURE AND PRECIPITATION OUTPUT.
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
MARCH 21.
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:
19590218 - 19700224 - 20070208 - 19800227 - 19730224
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:
19590218 - 19800301 - 19730223 - 19700224 - 20070206
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 25 - 29 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B A IDAHO B A NEVADA B A
W MONTANA N A E MONTANA A A WYOMING A A
UTAH N A ARIZONA B A COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A B AK N SLOPE B B
AK ALEUTIAN B N AK WESTERN B B AK INT BSN B B
AK S INT B B AK SO COAST B B AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 27 - MAR 04, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B A
SRN CALIF B B IDAHO B A NEVADA B N
W MONTANA B A E MONTANA A A WYOMING N A
UTAH B N ARIZONA B B COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A N OKLAHOMA A N
N TEXAS A N S TEXAS A N W TEXAS A B
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A N MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A N FL PENIN A N AK N SLOPE B B
AK ALEUTIAN B N AK WESTERN B B AK INT BSN B B
AK S INT B B 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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