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FXUS06 KWBC 162035
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 16 2024
6-10 DAY OUTLOOK FOR APR 22 - 26 2024
TRANSIENT 500-HPA HEIGHT PATTERN IS FORECAST ACROSS NORTH AMERICA DURING THE 6-10
DAY PERIOD. AT THE OUTSET OF THE PERIOD, TROUGHING AND NEGATIVE HEIGHT
ANOMALIES ARE 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. BY DAY-10, TROUGHING IS FORECAST TO DEVELOP ACROSS
THE WEST COAST. THE PATTERN ACROSS ALASKA IS PREDICTED TO TRANSITION FROM
ENHANCED RIDGING AND POSITIVE HEIGHT ANOMALIES AT THE OUTSET OF THE PERIOD TO
MORE INFLUENCE FROM TROUGHING OVER THE BERING SEA AND ARCTIC BY THE END OF THE
PERIOD. NEAR- TO ABOVE-NORMAL HEIGHTS ARE PREDICTED ACROSS HAWAII.
MODELS ARE IN GOOD AGREEMENT REGARDING ANOMALOUSLY COLD TEMPERATURES ACROSS THE
EASTERN 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 EAST FOR THE PERIOD AS A WHOLE,
ALONG WITH INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE WESTERN
CONUS, GREAT PLAINS, AND UPPER MISSISSIPPI VALLEY. TROUGHING IS FORECAST TO
BUILD ACROSS THE BERING SEA FOLLOWING INITIAL RIDGING ACROSS MAINLAND ALASKA
AND SOUTHEAST ALASKA EARLY IN THE PERIOD. THIS FAVORS A TREND TOWARD COOLER
TEMPERATURES ACROSS WESTERN ALASKA, WITH INCREASED CHANCES FOR BELOW-NORMAL
TEMPERATURES ALONG THE WEST COAST OF THE MAINLAND AND THE ALEUTIANS. ELEVATED
PROBABILITIES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR THE
REMAINDER OF THE MAINLAND AND SOUTHEAST ALASKA. NEAR- TO BELOW-NORMAL
TEMPERATURES ARE PREDICTED ACROSS THE HAWAIIAN ISLANDS.
SURFACE HIGH PRESSURE FORECAST TO MOVE ACROSS THE EAST FAVORS ELEVATED CHANCES
OF BELOW-NORMAL PRECIPITATION ACROSS PARTS OF THE NORTHEAST, MID-ATLANTIC, AND
OHIO VALLEY. TO THE SOUTH, ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION ARE
FORECAST ALONG A FRONTAL BOUNDARY EXTENDING ALONG THE GULF OF MEXICO COAST INTO
THE SOUTHEAST, 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. INCREASING TROUGHING ACROSS THE WEST FAVORS SLIGHTLY ENHANCED
CHANCES FOR ABOVE-NORMAL PRECIPITATION OVER THE SOUTHWEST, WITH ODDS CONTINUING
TO TILT TOWARD BELOW-NORMAL PRECIPITATION OVER THE PACIFIC NORTHWEST. INCREASED
SOUTHERLY FLOW ACROSS ALASKA AHEAD OF DEVELOPING TROUGHING OVER THE BERING SEA
FAVORS ENHANCED CHANCES FOR ABOVE-NORMAL PRECIPITATION ACROSS THE STATE.
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 100% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
CONTINUITY REGARDING THE PATTERN EVOLUTION, OFFSET BY LACK OF FORECAST TOOLS
DUE TO IT OUTAGE.
8-14 DAY OUTLOOK FOR APR 24 - 30 2024
THE 500-HPA HEIGHT PATTERN DURING WEEK-2 IS FORECAST TO CONTINUE TO DEPICT
AMPLIFIED RIDGING AND POSITIVE 500-HPA HEIGHT ANOMALIES CONTINUING TO EXPAND
ACROSS THE CENTRAL AND EASTERN CONUS. WEAK TROUGHS ARE PREDICTED ACROSS THE
WESTERN CONUS AND ALASKA. 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 70 PERCENT) ARE ACROSS THE GREAT PLAINS AND MIDDLE
MISSISSIPPI VALLEY, 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 BELOW-NORMAL TEMPERATURES ARE FAVORED ALONG THE WEST COAST
DUE TO MORE TROUGHING. DECREASING MID-LEVEL HEIGHTS FAVOR ELEVATED
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ACROSS PORTIONS OF WESTERN AND
SOUTHERN ALASKA, WITH ABOVE-NORMAL TEMPERATURE REMAINING FAVORED DOWNSTREAM
ACROSS THE NORTHEASTERN MAINLAND. INCREASED CHANCES FOR NEAR- TO 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. NEAR-NORMAL PRECIPITATION IS FAVORED ACROSS HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 100% OF TODAY'S 0Z GFS
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 AMPLIFIED RIDGING ACROSS THE EASTERN HALF OF THE
CONUS AND A SUBSEQUENT WARMER PATTERN, OFFSET BY LACK OF FORECAST TOOLS DUE TO
IT OUTAGE.
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 22 - 26 2024
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR APR 24 - 30 2024
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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