856
FXUS06 KWBC 071902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED AUGUST 07 2024
6-10 DAY OUTLOOK FOR AUG 13 - 17 2024
A GENERALLY AMPLIFIED 500-HPA HEIGHT PATTERN IS FORECAST ACROSS NORTH AMERICA
DURING THE 6-10 DAY PERIOD, WITH TROUGHING OVER THE BERING SEA AND EXTENDING
ALONG THE WEST COAST OF THE CONUS. BROAD RIDGING IS PREDICTED ACROSS THE
CENTRAL CONUS, WITH TROUGHING DOWNSTREAM OVER THE NORTHEAST AND NORTHWEST
ATLANTIC. TODAY’S MANUAL HEIGHT BLEND DEPICTS NEAR-NORMAL HEIGHTS OVER MOST OF
THE CONUS, WITH SLIGHTLY ABOVE-NORMAL HEIGHTS OVER PARTS OF THE GREAT PLAINS
AND BELOW-NORMAL HEIGHTS OVER THE NORTHEAST AND NORTHERN MID-ATLANTIC.
BELOW-NORMAL HEIGHTS ARE PREDICTED ACROSS NEARLY ALL OF ALASKA, UNDERNEATH THE
INFLUENCE OF TROUGHING. ABOVE-NORMAL HEIGHTS ARE FAVORED FOR HAWAII.
THE EVOLVING MID-LEVEL PATTERN FAVORS ELEVATED PROBABILITIES OF ABOVE-NORMAL
TEMPERATURES OVER MOST OF THE INTERIOR CONUS DURING THE 6-10 DAY PERIOD. THE
HIGHEST PROBABILITIES (GREATER THAN 70 PERCENT) ARE FORECAST ACROSS THE
SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY, WITH INCREASING CONCERNS FOR
EXCESSIVE HEAT OVER THESE REGIONS. THE UNCALIBRATED GUIDANCE FROM THE 0Z GEFS,
ECENS, AND CMCE SUPPORT INCREASED CHANCES FOR BELOW-NORMAL TEMPERATURES NEAR
THE WEST COAST AND ALSO ALONG THE EASTERN SEABOARD. THE ECENS REFORECAST TOOL
IS LESS ROBUST WITH BELOW-NORMAL TEMPERATURES IN THE EAST COMPARED TO THE GEFS
AND CMCE REFORECAST TOOLS, BUT ANTECEDENT HEAVY RAIN AND SATURATED GROUND TILTS
THE ODDS TO SLIGHTLY FAVOR BELOW-NORMAL TEMPERATURES OVER PARTS OF THE
NORTHEAST AND MID-ATLANTIC. ANOMALOUS TROUGHING OVER THE BERING SEA FAVORS
INCREASED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES OVER MUCH OF ALASKA,
EXCLUDING THE NORTHERN MAINLAND WHERE ABOVE-NORMAL TEMPERATURES ARE SLIGHTLY
FAVORED. ABOVE-NORMAL TEMPERATURE CHANCES ARE INCREASED OVER HAWAII, CONSISTENT
WITH THE REFORECAST CONSOLIDATION TOOL.
SHORTWAVE IMPULSES ARE FORECAST TO PROPAGATE OVERTOP THE EXPANDING RIDGE OVER
THE CENTRAL CONUS. THIS FAVORS INCREASED CHANCES FOR ABOVE-NORMAL PRECIPITATION
ACROSS MUCH OF THE NORTHERN U.S., INCLUDING INTO PARTS OF THE EAST WHICH ARE
LIKELY TO HAVE A RELATIVELY DRIER PATTERN IN THE DAYS LEADING UP TO THE
FORECAST PERIOD IN THE WAKE OF TROPICAL STORM DEBBY. PROBABILITIES FOR
ABOVE-NORMAL PRECIPITATION ARE ALSO INCREASED ACROSS THE FOUR CORNERS TIED TO
INCREASING MONSOONAL MOISTURE UNDERNEATH THE FAVORABLE MID-LEVEL RIDGE
POSITIONING OVER THE REGION. NEAR- TO BELOW-NORMAL PRECIPITATION IS FAVORED
ALONG THE GULF COAST AND GREAT BASIN SUPPORTED BY THE GEFS AND ECENS
UNCALIBRATED AND REFORECAST TOOLS. TROUGHING AND INCREASED ONSHORE FLOW FAVORS
ELEVATED CHANCES FOR ABOVE-NORMAL PRECIPITATION OVER THE ALEUTIANS AND MAINLAND
ALASKA. NEAR- TO BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ENHANCED ACROSS
SOUTHEAST ALASKA UNDERNEATH GREATER INFLUENCE FROM RIDGING OVER CANADA. NEAR-
TO BELOW-NORMAL PRECIPITATION IS FORECAST OVER HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 0Z GFS CENTERED ON
DAY 8, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY'S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 20% 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
GOOD DYNAMICAL MODEL AGREEMENT REGARDING THE MID-LEVEL PATTERN, OFFSET BY WEAK
SIGNALS IN THE PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR AUG 15 - 21 2024
DYNAMICAL MODELS CONTINUE TO FAVOR INCREASING 500-HPA HEIGHTS ACROSS THE CONUS
DURING WEEK-2, WITH A 595-DM RIDGE CENTER DEPICTED IN THE 0Z ECENS, GEFS, AND
CMCE OVER THE FOUR CORNERS REGION BY THE END OF THE PERIOD. THE TROUGHS ALONG
THE EAST AND WEST COASTS OF THE CONUS ARE ALSO FORECAST TO WEAKEN RELATIVE TO
THE 6-10 DAY PERIOD. AS A RESULT, THE WEEK-2 MANUAL HEIGHT BLEND INDICATES
NEAR- TO ABOVE-NORMAL HEIGHTS OVER MOST OF THE CONUS, WITH THE LARGEST POSITIVE
HEIGHT ANOMALIES (GREATER THAN +30 METERS) OVER THE UPPER MIDWEST. TROUGHING
OVER THE BERING SEA IS FORECAST TO LIFT OUT EARLY IN WEEK-2 WITH A MORE ZONALLY
ORIENTED FLOW PATTERN DEVELOPING OVER ALASKA. THIS FAVORS NEAR- TO ABOVE-NORMAL
HEIGHTS ACROSS SOUTHERN ALASKA IN THE MANUAL BLEND. BELOW NORMAL HEIGHTS REMAIN
FORECAST ACROSS THE WESTERN MAINLAND. ABOVE-NORMAL HEIGHTS ARE PREDICTED ACROSS
HAWAII.
EXPANDING RIDGING SUPPORTS INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER
MUCH OF THE CONUS. PROBABILITIES EXCEED 70 PERCENT OVER MUCH OF THE SOUTHERN
PLAINS AND LOWER MISSISSIPPI VALLEY, WITH EXCESSIVE HEAT A CONCERN OVER PARTS
OF THESE REGIONS. ACROSS PARTS OF THE MID-ATLANTIC INTO SOUTHERN NEW ENGLAND,
LINGERING WEAK TROUGHING COMBINED WITH SATURATED GROUND FAVORS TEMPERATURES
CLOSER TO NORMAL, WITH LARGER POSITIVE HEIGHT ANOMALIES FAVORING ABOVE-NORMAL
TEMPERATURES ACROSS NORTHERN NEW ENGLAND. THE GEFS AND ECENS REFORECAST TOOLS
SUPPORT ENHANCED PROBABILITIES OF BELOW-NORMAL TEMPERATURES NEAR THE WEST
COAST. ELEVATED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE FORECAST TO
PERSIST OVER MUCH OF ALASKA TIED TO TROUGHING EARLY IN THE PERIOD, WITH THE
EXCEPTION BEING THE NORTHEASTERN MAINLAND WHERE NEAR- TO ABOVE-NORMAL
TEMPERATURES ARE FAVORED. ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS HAWAII
SUPPORTED BY THE REFORECAST CONSOLIDATION TOOL.
ABOVE-NORMAL PRECIPITATION PROBABILITIES REMAIN ELEVATED OVER MUCH OF THE
NORTHWEST, ROCKIES, AND NORTHERN TO CENTRAL GREAT PLAINS THROUGHOUT WEEK-2,
WITH NEAR- TO BELOW-NORMAL PRECIPITATION CHANCES ELEVATED OVER PORTIONS OF
CALIFORNIA AND THE GREAT BASIN. FORECAST TOOLS OFFER MIXED SIGNALS ACROSS THE
NORTH-CENTRAL CONUS, WITH THE ECENS (GEFS) DEPICTING HIGHER CHANCES FOR ABOVE
(BELOW) NORMAL PRECIPITATION. THE ACTIVE STORM TRACK DISCUSSED IN THE 6-10 DAY
PERIOD IS LIKELY TO PERSIST, ALTHOUGH MORE RIDGING WOULD SUPPORT RELATIVELY
DRIER CONDITIONS. THEREFORE, NEAR-NORMAL PRECIPITATION IS FORECAST OVER MUCH OF
THE MIDWEST, WITH A SLIGHT TILT TOWARD INCREASED ODDS FOR BELOW-NORMAL
PRECIPITATION OVER THE SOUTHERN PLAINS AND LOWER MISSISSIPPI VALLEY. THE
POTENTIAL FOR TROPICAL CYCLONE ACTIVITY REDUCES CONFIDENCE ALONG THE GULF COAST
AND SOUTH FLORIDA, WITH NEAR- TO WEAKLY ABOVE-NORMAL PRECIPITATION
PROBABILITIES FAVORED OVER THESE AREAS. CHANCES FOR ABOVE-NORMAL PRECIPITATION
ARE SLIGHTLY ENHANCED ACROSS THE NORTHEAST AND MID-ATLANTIC DUE TO WEAKER
MID-LEVEL HEIGHT ANOMALIES AND POTENTIAL FOR FRONTAL ACTIVITY. NEAR- TO
ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED OVER ALASKA UNDERNEATH
ENHANCED WESTERLY MID-LEVEL FLOW, AND NEAR- TO BELOW-NORMAL PRECIPITATION
CHANCES ARE INCREASED OVER HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 40% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 20% OF TODAY'S 0Z CANADIAN 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 BROADENING RIDGING OVER THE CONUS, OFFSET BY
CONTINUED WEAK SIGNALS IN THE PRECIPITATION TOOLS AND UNCERTAINTY IN THE
TROPICS.
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
AUGUST 15.
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:
19520803 - 20090728 - 19770816 - 19580821 - 19990802
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:
19520804 - 19990804 - 20090728 - 19770816 - 19530802
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 13 - 17 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B N NRN CALIF B N
SRN CALIF B N IDAHO N N NEVADA N B
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 N OKLAHOMA A N
N TEXAS A B S TEXAS A B W TEXAS A N
MINNESOTA A A IOWA A A MISSOURI A A
ARKANSAS A N LOUISIANA A B WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A N
INDIANA A A OHIO N A KENTUCKY A A
TENNESSEE A A ALABAMA A N NEW YORK N N
VERMONT N N NEW HAMP N N MAINE A B
MASS N N CONN B N RHODE IS B N
PENN B A NEW JERSEY B A W VIRGINIA N A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA N A S CAROLINA A A GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE A 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 N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 15 - 21 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N A NRN CALIF B N
SRN CALIF B N IDAHO A N NEVADA A B
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA A A
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A A
MASS A A CONN N A RHODE IS N A
PENN A N NEW JERSEY N A W VIRGINIA A A
MARYLAND N A DELAWARE N A VIRGINIA N N
N CAROLINA N N S CAROLINA A N GEORGIA A N
FL PNHDL A N FL PENIN A N AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL B N
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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