####018008373#### 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. $$