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FXUS06 KWBC 051912
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT MON AUGUST 05 2024
6-10 DAY OUTLOOK FOR AUG 11 - 15 2024
A GENERALLY AMPLIFIED 500-HPA HEIGHT PATTERN IS FORECAST ACROSS THE HIGHER
LATITUDES OF NORTH AMERICA DURING THE 6-10 DAY PERIOD, WITH TROUGHING OVER
ALASKA AND BROAD RIDGING EXTENDING ACROSS MUCH OF CANADA. THE PREDICTED
MID-LEVEL HEIGHT PATTERN ACROSS THE CONUS IS MORE VARIABLE, WITH SHORTWAVE
ENERGY PREDICTED TO UNDERCUT THE RIDGING OVER CANADA AND INTERACT WITH TROPICAL
STORM DEBBY OVER THE EASTERN CONUS PRIOR TO THE START OF THE PERIOD. A TREND
TOWARD MORE RIDGING OVER THE CENTRAL CONUS IS FORECAST DURING THE PERIOD, WITH
TROUGHING PREDICTED OVER THE WEST AND EAST COASTS. TODAY’S MANUAL HEIGHT BLEND
DEPICTS NEAR-NORMAL HEIGHTS OVER MOST OF THE CONUS, WITH ABOVE-NORMAL HEIGHTS
OVER THE SOUTHERN PLAINS AND BELOW-NORMAL HEIGHTS OVER THE GREAT LAKES AND
NORTHEAST. BELOW-NORMAL HEIGHTS ARE PREDICTED ACROSS THE ALEUTIANS AND MAINLAND
ALASKA, WITH NEAR- TO ABOVE-NORMAL HEIGHTS FORECAST ACROSS SOUTHEAST ALASKA.
ABOVE-NORMAL HEIGHTS ARE PREDICTED OVER HAWAII.
SHORTWAVE TROUGHING FAVORS INCREASED CHANCES OF BELOW-NORMAL TEMPERATURES OVER
THE NORTH-CENTRAL U.S. PRIOR TO THE START OF THE PERIOD. THIS FEATURE IS
FORECAST TO SHIFT EASTWARD BY THE START OF THE 6-10 DAY PERIOD, ALTHOUGH
BELOW-NORMAL TEMPERATURES ARE LIKELY TO LINGER BEFORE MODERATING TOWARD THE END
OF THE PERIOD. A MORE NORTHERLY MID-LEVEL FLOW PATTERN IS ALSO FAVORED ACROSS
THE EASTERN U.S. IN THE WAKE OF TROPICAL STORM DEBBY, WITH ANY LINGERING
MOISTURE ALSO CONTRIBUTING TO COOLER TEMPERATURES. THEREFORE, INCREASED
PROBABILITIES FOR BELOW-NORMAL TEMPERATURES ARE HIGHLIGHTED ACROSS MUCH OF THE
NORTHERN PLAINS, UPPER MIDWEST, NORTHEAST, AND MID-ATLANTIC. THE GEFS, ECENS,
AND CMCE REFORECAST TOOLS ALL SUPPORT INCREASED CHANCES FOR ABOVE-NORMAL
TEMPERATURES ACROSS THE WESTERN THIRD OF THE CONUS, AND ALONG THE SOUTHERN TIER
GIVEN THE TREND TOWARD HIGHER MID-LEVEL HEIGHTS. ANOMALOUS TROUGHING FAVORS
INCREASED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES OVER MUCH OF ALASKA,
EXCLUDING THE NORTHEASTERN MAINLAND AND SOUTHEAST ALASKA WHERE ABOVE-NORMAL
TEMPERATURES ARE SLIGHTLY FAVORED. ABOVE-NORMAL TEMPERATURE CHANCES ARE
INCREASED OVER HAWAII, CONSISTENT WITH THE REFORECAST CONSOLIDATION TOOL.
WEAK TROUGHING ALONG THE WEST COAST AND A STORM TRACK ACROSS THE NORTHERN TIER
OF THE CONUS FAVORS INCREASED CHANCES FOR ABOVE-NORMAL PRECIPITATION OVER MUCH
OF THE WESTERN CONUS, NORTHERN AND CENTRAL PLAINS, AND UPPER AND MIDDLE
MISSISSIPPI VALLEY. LINGERING IMPACTS FROM TROPICAL STORM DEBBY ARE POSSIBLE
ACROSS THE NORTHEAST AND MID-ATLANTIC AT THE OUTSET OF THE PERIOD, ALTHOUGH A
DRYING TREND IS PREDICTED BEHIND THE SYSTEM. THEREFORE, ONLY A SLIGHT TILT
TOWARD ABOVE-NORMAL PRECIPITATION IS HIGHLIGHTED ACROSS PARTS OF THE
NORTHEASTERN U.S., WITH BELOW-NORMAL PRECIPITATION PROBABILITIES INCREASED
ACROSS THE INTERIOR EASTERN CONUS STRETCHING BACK INTO THE SOUTHERN PLAINS. THE
ECENS REFORECAST TOOL ALONG WITH UNCALIBRATED GUIDANCE FROM THE GEFS AND ECENS
SUPPORT A SLIGHT TILT TOWARD INCREASED BELOW-NORMAL PRECIPITATION PROBABILITIES
OVER PARTS OF SOUTHERN CALIFORNIA. TROUGHING AND INCREASED ONSHORE FLOW FAVORS
INCREASED CHANCES FOR ABOVE-NORMAL PRECIPITATION OVER THE ALEUTIANS AND
MAINLAND ALASKA. BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ENHANCED ACROSS
SOUTHEAST ALASKA UNDERNEATH GREATER INFLUENCE FROM RIDGING OVER CANADA. NEAR-
TO ABOVE-NORMAL PRECIPITATION IS FORECAST OVER HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 40% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
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: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT AMONG THE VARIOUS FORECAST TOOLS, OFFSET BY SOME UNCERTAINTY RELATED
TO LINGERING IMPACTS FROM TROPICAL STORM DEBBY IN THE EAST AND A MORE
TRANSITIONAL MID-LEVEL HEIGHT PATTERN EVOLUTION OVER THE CENTRAL CONUS.
8-14 DAY OUTLOOK FOR AUG 13 - 19 2024
A TREND TOWARD MORE RIDGING IS FORECAST ACROSS THE INTERIOR WESTERN AND CENTRAL
CONUS DURING WEEK-2, WITH WEAK TROUGHING REMAINING OVER BOTH COASTS. THE MANUAL
500-HPA HEIGHT BLEND CONTINUES TO DEPICT NEAR-NORMAL HEIGHTS OVER MOST OF THE
CONUS, WITH WEAK POSITIVE HEIGHT ANOMALIES OVER THE NORTH-CENTRAL CONUS AND
SLIGHTLY NEGATIVE ANOMALIES NEAR THE ATLANTIC AND PACIFIC COASTS. A GENERALLY
PERSISTENT MID-LEVEL PATTERN IS FORECAST ACROSS ALASKA, WITH TROUGHING OVER
MOST OF THE STATE. THIS FAVORS A SIMILAR HEIGHT PATTERN AS IN THE 6-10 DAY
PERIOD WITH BELOW-NORMAL HEIGHTS FORECAST ACROSS THE ALEUTIANS AND MAINLAND
ALASKA, AND NEAR-NORMAL HEIGHTS DOWNSTREAM OVER THE EASTERN MAINLAND AND
SOUTHEAST ALASKA. ABOVE-NORMAL HEIGHTS REMAIN FORECAST ACROSS HAWAII.
EXPANDING RIDGING SUPPORTS INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER
MUCH OF THE CENTRAL CONUS, AND EXTENDING INTO THE NORTHWEST AND SOUTHEAST.
PROBABILITIES EXCEED 60 PERCENT OVER MUCH OF THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY, WITH SOME CONCERNS FOR EXCESSIVE HEAT EMERGING DURING THE
PERIOD. THERE IS MORE UNCERTAINTY IN THE EAST WHERE RELATIVELY COOLER
TEMPERATURES MAY LINGER INTO THE START OF WEEK-2, BEFORE TRENDING WARMER.
THEREFORE, NEAR- TO BELOW-NORMAL TEMPERATURES ARE FORECAST OVER MUCH OF THE
EAST FOR THE PERIOD AS A WHOLE AND ANTECEDENT RAINFALL AND SATURATED GROUND MAY
ALSO FAVOR A REDUCTION IN SENSIBLE HEATING. THE GEFS, ECENS, AND CMCE
REFORECAST TOOLS SUPPORT ENHANCED PROBABILITIES OF BELOW-NORMAL TEMPERATURES
OVER PARTS OF CALIFORNIA AND NEVADA. ELEVATED PROBABILITIES FOR BELOW-NORMAL
TEMPERATURES ARE FORECAST TO PERSIST OVER MUCH OF ALASKA TIED TO TROUGHING AND
NEGATIVE MID-LEVEL HEIGHT ANOMALIES, WITH THE EXCEPTIONS BEING PARTS OF
SOUTHEAST ALASKA AND THE NORTHEASTERN MAINLAND WHERE NEAR- TO ABOVE-NORMAL
TEMPERATURES ARE FAVORED. ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS HAWAII.
ABOVE-NORMAL PRECIPITATION PROBABILITIES REMAIN ELEVATED OVER MUCH OF THE
NORTHERN TIER OF THE CONUS THROUGHOUT WEEK-2. ACROSS THE SOUTH THERE IS MORE
DISCREPANCY BETWEEN THE WETTER REFORECAST TOOLS AND DRIER UNCALIBRATED
GUIDANCE. GIVEN THE PREDICTED EXPANSION OF THE RIDGE, A TILT TOWARD NEAR- TO
BELOW-NORMAL PRECIPITATION IS FORECAST ACROSS THE SOUTHERN CONUS. 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. ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED OVER
THE ALEUTIANS AND MAINLAND ALASKA, WITH NEAR- TO BELOW-NORMAL PRECIPITATION
CHANCES REMAINING SLIGHTLY INCREASED OVER SOUTHEAST ALASKA. PROBABILITIES FOR
NEAR- TO ABOVE-NORMAL PRECIPITATION ARE INCREASED OVER HAWAII, SUPPORTED BY THE
REFORECAST CONSOLIDATION TOOL.
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 MORE RIDGING OVER THE CENTRAL U.S., OFFSET BY WEAK
SIGNALS IN THE PRECIPITATION TOOLS.
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:
19520801 - 19930802 - 20030725 - 20060720 - 19740728
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:
19520801 - 19930803 - 20030725 - 19770814 - 19900716
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 11 - 15 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF N A
SRN CALIF A N IDAHO A A NEVADA A A
W MONTANA N A E MONTANA N A WYOMING N A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA N A S DAKOTA B A
NEBRASKA B A KANSAS A A OKLAHOMA A N
N TEXAS A B S TEXAS A N W TEXAS A N
MINNESOTA B A IOWA B N MISSOURI B N
ARKANSAS A B LOUISIANA A N WISCONSIN B N
ILLINOIS B N MISSISSIPPI A B MICHIGAN B N
INDIANA B B OHIO B B KENTUCKY B B
TENNESSEE B B ALABAMA A B NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B N NEW JERSEY B A W VIRGINIA B B
MARYLAND B N DELAWARE B A VIRGINIA B N
N CAROLINA B N S CAROLINA B N GEORGIA N B
FL PNHDL A N FL PENIN A N AK N SLOPE N 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 A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 13 - 19 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON A A NRN CALIF B A
SRN CALIF B B IDAHO A A NEVADA A N
W MONTANA A A E MONTANA A A WYOMING A A
UTAH A A ARIZONA A N COLORADO A A
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 N
MINNESOTA A A IOWA A A MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A N MISSISSIPPI A N MICHIGAN A N
INDIANA A N OHIO N N KENTUCKY A N
TENNESSEE A B ALABAMA A N NEW YORK A N
VERMONT A N NEW HAMP N N MAINE A N
MASS N N CONN N N RHODE IS B N
PENN N N NEW JERSEY B N W VIRGINIA N N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA N N S CAROLINA N N GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE N 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 N 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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