781
FXUS06 KWBC 152034
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON APRIL 15 2024
6-10 DAY OUTLOOK FOR APR 21 - 25 2024
A TRANSIENT 500-HPA HEIGHT PATTERN IS FORECAST ACROSS NORTH AMERICA DURING THE
6-10 DAY PERIOD. AT THE OUTSET OF THE PERIOD, TROUGHING IS PREDICTED ACROSS
EASTERN CANADA AND EXTENDING INTO THE GREAT LAKES AND NORTHEAST. A TREND TOWARD
HIGHER MID-LEVEL HEIGHTS IS FORECAST IN THE EAST LATER IN THE PERIOD AS THIS
INITIAL TROUGHING LIFTS OUT AND RIDGING SHIFTS EASTWARD ACROSS THE CONUS. THE
0Z ECMWF AND CANADIAN ENSEMBLES ARE MORE AMPLIFIED WITH THIS RIDGE COMPARED TO
THE 0Z GEFS, WITH ALL MODELS IN AGREEMENT FOR MORE TROUGHING TO BUILD INTO THE
WESTERN CONUS AND OVER THE BERING SEA AS THE PERIOD PROGRESSES. TODAY’S MANUAL
500-HPA HEIGHT BLEND DEPICTS NEAR-NORMAL HEIGHTS ACROSS THE EASTERN SEABOARD,
AND ABOVE-NORMAL HEIGHTS ACROSS THE REMAINDER OF THE CONUS. NEAR- TO
BELOW-NORMAL (ABOVE-NORMAL) HEIGHTS ARE PREDICTED ACROSS ALASKA (HAWAII).
MODELS ARE IN GOOD AGREEMENT REGARDING ANOMALOUSLY COLD TEMPERATURES ACROSS
MUCH OF THE EASTERN HALF OF THE CONUS AT THE START OF THE PERIOD, WITH
MODERATION LIKELY BY THE SECOND HALF OF THE PERIOD. TODAY’S FORECAST DEPICTS
ENHANCED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES OVER MUCH OF THE EASTERN
CONUS AND SOUTHERN PLAINS FOR THE PERIOD AS A WHOLE, ALONG WITH INCREASED
CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE WESTERN CONUS, NORTHERN AND
CENTRAL PLAINS, AND UPPER MISSISSIPPI VALLEY. ALTHOUGH THE ECMWF REFORECAST
TOOL IS NOT AS ROBUST WITH BELOW-NORMAL TEMPERATURE PROBABILITIES IN THE EAST
COMPARED TO THE GEFS REFORECAST TOOL, THERE IS BETTER AGREEMENT AMONG THE
UNCALIBRATED GUIDANCE REGARDING COOLER TEMPERATURES. TROUGHING IS FORECAST TO
BUILD ACROSS THE BERING SEA FOLLOWING SOME WEAK RIDGING ACROSS MAINLAND ALASKA
AND SOUTHEAST ALASKA EARLY IN THE PERIOD. THIS FAVORS A TREND TOWARD COOLER
TEMPERATURES ACROSS THE STATE, WITH THE FORECAST BEING A COMPROMISE BETWEEN THE
WARMER REFORECAST GUIDANCE AND COOLER UNCALIBRATED TOOLS. THE LARGEST
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE FAVORED ACROSS THE WESTERN
MAINLAND AND ALEUTIANS, WITH NEAR- TO SLIGHTLY ABOVE-NORMAL TEMPERATURES
FORECAST ACROSS THE REMAINDER OF THE MAINLAND AND SOUTHEAST ALASKA.
BELOW-NORMAL TEMPERATURES ARE PREDICTED ACROSS THE HAWAIIAN ISLANDS CONSISTENT
WITH THE CONSOLIDATION FORECAST TOOL.
THE TRANSIENT PATTERN FAVORS A LARGE AREA OF NEAR-NORMAL PRECIPITATION ACROSS
THE CONUS DURING THE PERIOD. SURFACE HIGH PRESSURE FORECAST TO MOVE ACROSS THE
EAST FAVORS ELEVATED CHANCES OF BELOW-NORMAL PRECIPITATION ACROSS THE
NORTHEAST. TO THE SOUTH, ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION ARE
FORECAST ALONG A FRONTAL BOUNDARY EXTENDING FROM THE SOUTHERN PLAINS TO THE
MID-ATLANTIC, WITH RETURN FLOW AROUND SURFACE HIGH PRESSURE POSSIBLY LEADING TO
RENEWED PRECIPITATION CHANGES ACROSS PARTS OF THE CENTRAL CONUS BY THE END OF
THE PERIOD. ABOVE-NORMAL 500-HPA HEIGHTS ACROSS THE WEST FAVOR ENHANCED CHANCES
FOR NEAR- TO BELOW-NORMAL PRECIPITATION. INCREASED SOUTHERLY FLOW ACROSS ALASKA
AHEAD OF DEVELOPING TROUGHING OVER THE BERING SEA FAVORS ENHANCED CHANCES FOR
ABOVE-NORMAL PRECIPITATION ACROSS THE STATE. NEAR- TO BELOW-NORMAL
PRECIPITATION CHANCES ARE ELEVATED ACROSS HAWAII DUE TO INCREASING RIDGING OVER
THE CENTRAL PACIFIC.
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
GENERALLY GOOD AGREEMENT IN THE TOOLS REGARDING THE TEMPERATURE AND
PRECIPITATION FORECAST, OFFSET BY SOME UNCERTAINTY RELATED TO A TRANSIENT
PATTERN.
8-14 DAY OUTLOOK FOR APR 23 - 29 2024
THE 500-HPA HEIGHT PATTERN DURING WEEK-2 IS FORECAST TO CONTINUE TO TREND
TOWARD MORE RIDGING ACROSS THE EASTERN CONUS AND WEAK TROUGHING ACROSS THE
WESTERN CONUS AND ALASKA. THE MANUAL HEIGHT BLEND DEPICTS THE HIGHEST POSITIVE
HEIGHT ANOMALIES (+60 METERS) ACROSS THE OHIO VALLEY AND NORTHEAST. NEAR-NORMAL
HEIGHTS ARE FAVORED FROM THE ROCKIES WESTWARD, WITH BELOW-NORMAL HEIGHTS
PREDICTED ACROSS MUCH OF ALASKA ASSOCIATED WITH TROUGHING ACROSS THE BERING SEA
AND WESTERN MAINLAND. NEAR- TO ABOVE-NORMAL HEIGHTS ARE FORECAST ACROSS HAWAII.
THE PREVAILING MID-LEVEL HEIGHT PATTERN ACROSS THE CONUS FAVORS AN ANOMALOUSLY
WARM PATTERN ACROSS MUCH OF THE CONUS EAST OF THE ROCKIES DURING LATE APRIL.
THE HIGHEST PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES (GREATER THAN 60
PERCENT) ARE ACROSS THE GREAT PLAINS, WITH DECREASING CHANCES FURTHER EAST AS
THERE IS SOME UNCERTAINTY RELATED TO THE LINGERING BELOW-NORMAL TEMPERATURES AT
THE START OF THE PERIOD. NEAR- TO SLIGHTLY BELOW-NORMAL TEMPERATURES ARE
FAVORED ALONG THE WEST COAST DUE TO MORE TROUGHING AND SUPPORTED BY THE
UNCALIBRATED FORECAST TOOLS, AND TELECONNECTION ANALYSIS WITH THE POSITIVE
HEIGHT ANOMALY CENTER IN THE CENTRAL PACIFIC. ACROSS ALASKA, THE REFORECAST
TOOLS CONTINUE TO DEPICT INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS
MUCH OF THE STATE. HOWEVER, THE FORECAST LEANS TOWARD HIGHER PROBABILITIES OF
BELOW-NORMAL TEMPERATURES GIVEN THE FORECAST INCREASE IN TROUGHING AS WELL AS
INCREASED SIGNALS FOR BELOW-NORMAL TEMPERATURES IN THE UNCALIBRATED TOOLS AND
TELECONNECTION ANALYSIS. INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES REMAIN
FORECAST ACROSS HAWAII.
THE TREND TOWARD RELATIVELY LOWER MID-LEVEL HEIGHTS ACROSS THE WESTERN CONUS
FAVORS INCREASING CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS A LARGE PORTION
OF THE CONUS, AIDED IN PART BY INCREASED SOUTHERLY RETURN FLOW IN THE EAST.
THIS PATTERN SETS THE STAGE FOR MULTIPLE EPISODES OF PRECIPITATION AS EJECTING
SHORTWAVE DISTURBANCES PROMOTE A FAVORABLE ENVIRONMENT FOR ENHANCED
PRECIPITATION ACROSS PARTS OF THE CENTRAL CONUS. NEAR-NORMAL PRECIPITATION IS
FAVORED ALONG THE EASTERN SEABOARD, FARTHER DISPLACED FROM THE FORCING
UPSTREAM. PROBABILITIES FOR ABOVE-NORMAL PRECIPITATION REMAIN ELEVATED ACROSS
ALASKA CONSISTENT WITH THE REFORECAST TOOLS AND TROUGHING OVER THE REGION.
ABOVE-NORMAL PRECIPITATION CHANCES ARE ALSO INCREASED ACROSS 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: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT REGARDING AMPLIFIED RIDGING ACROSS THE EASTERN HALF OF THE
CONUS AND A SUBSEQUENT WARMER PATTERN, OFFSET BY LOWER CONFIDENCE IN THE
PRECIPITATION FORECAST.
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
APRIL 18.
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:
20080411 - 19770418 - 19640426 - 19550412 - 19990405
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:
20080410 - 19770419 - 19640425 - 19550412 - 19610418
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR APR 21 - 25 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A B COLORADO A A
NEW MEXICO A A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS N N OKLAHOMA B N
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA N N MISSOURI B N
ARKANSAS B N LOUISIANA B A WISCONSIN N N
ILLINOIS B N MISSISSIPPI B A MICHIGAN N N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B A NEW YORK B B
VERMONT N B NEW HAMP N B MAINE N B
MASS B B CONN B B RHODE IS B B
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 N A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B A AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N A AK PNHDL N A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR APR 23 - 29 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON A N NRN CALIF N A
SRN CALIF B A IDAHO A A NEVADA A A
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA A A S DAKOTA A A
NEBRASKA A A KANSAS A A OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A A LOUISIANA A A WISCONSIN A A
ILLINOIS A A MISSISSIPPI A A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS N N CONN N N RHODE IS N N
PENN A N NEW JERSEY A N W VIRGINIA A A
MARYLAND A N DELAWARE N N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE B A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A 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.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
The Nexlab HPC Page Main Text Page