088
FXUS06 KWBC 061902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE AUGUST 06 2024
6-10 DAY OUTLOOK FOR AUG 12 - 16 2024
A GENERALLY AMPLIFIED 500-HPA HEIGHT PATTERN IS FORECAST ACROSS NORTH AMERICA,
ESPECIALLY THE HIGHER LATITUDES, DURING THE 6-10 DAY PERIOD. AMPLIFIED
MID-LEVEL TROUGHING IS ANTICIPATED OVER AND JUST WEST OF ALASKA, WITH BROAD
RIDGING EXTENDING ACROSS MUCH OF CANADA, CENTERED NEAR HUDSON BAY. THIS RIDGE
IS A LITTLE STRONGER THAN YESTERDAY, WITH MEAN 500-HPA HEIGHT ANOMALIES
EXCEEDING 150 DM. FARTHER EAST, MID-LEVEL TROUGHING IS ANTICIPATED, WITH
NEGATIVE HEIGHT ANOMALIES MAXIMIZED ALONG OR JUST OFF THE EAST COAST OF THE
CONTIGUOUS UNITED STATES (CONUS).
THE PREDICTED MID-LEVEL HEIGHT PATTERN ACROSS THE CONUS IS SOMEWHAT VARIABLE
BUT GENERALLY NOT PROGRESSIVE, WITH MEAN MID-LEVEL TROUGHING ALONG OR NEAR BOTH
CONUS COASTS AND RIDGING IN THE MIDDLE OF THE COUNTRY. WITH TIME, THE CENTRAL
CONUS RIDGE AMPLIFIES SLIGHTLY AND DRIFTS SLIGHTLY WESTWARD, WITH ITS AXIS
EVENTUALLY EXTENDING NORTH FROM THE SOUTHERN GREAT PLAINS TO THE MAXIMUM
500-HPA HEIGHT ANOMALIES OVER HUDSON BAY. ALONG THE WEST COAST, THE MID-LEVEL
TROUGH WILL OSCILLATE IN STRENGTH, WITH AN AXIS JUST OFF THE WEST COAST BY THE
END OF THE PERIOD. THE TROUGH NEAR THE EAST COAST - SOMEWHAT ENHANCED BY THE
REMNANTS OF TROPICAL STORM DEBBY - IS EXPECTED TO DEAMPLIFY BUT NOT DISSIPATE,
ENDING THE 6- TO 10-DAY PERIOD AS A FAIRLY WEAK BUT FULL-LATITUDE FEATURE ALONG
OR JUST INLAND FROM THE EAST COAST. THE MID-LEVEL TROUGH WEST OF ALASKA GETS
REINFORCED, RESULTING IN A MEAN 500-HPA HEIGHT ANOMALY AROUND -150 DM OVER THE
CHUKCHI SEA. WEAK 500-HPA FLOW IS EXPECTED NEAR HAWAII, WITH HEIGHTS AVERAGING
SLIGHTLY ABOVE NORMAL AND A MAXIMUM POSITIVE HEIGHT ANOMALY EAST OF THE ISLAND
CHAIN.
AS SHORTWAVE TROUGHING BECOMES ESTABLISHED ALONG THE EASTERN SEABOARD,
SUBNORMAL TEMPERATURES INITIALLY OVER THE NORTH-CENTRAL CONUS SHOULD SHIFT
EASTWARD AS THE NATION’S MIDSECTION SLOWLY WARMS UP. THE UNUSUALLY COOL WEATHER
IN THE EAST COULD BE REINFORCED BY ANOMALOUS NORTHERLY FLOW IN THE WAKE OF
HURRICANE DEBBY. THE SLOWLY INCREASING TEMPERATURES IN THE NORTH-CENTRAL CONUS
ARE EXPECTED TO RESULT IN NEAR-NORMAL TEMPERATURES IN THE 6-10 DAY MEAN, WITH
ELEVATED CHANCES FOR UNUSUAL WARMTH BOTH TO THE NORTH AND THE SOUTH WHERE THERE
ARE MORE POSITIVE 500-HPA HEIGHT ANOMALIES. BIAS-CORRECTIONS ON THE ENSEMBLES
TEND TO INCREASE THE COLD SIGNAL OVER THE NORTH-CENTRAL CONUS, BUT THIS IS
INCONSISTENT WITH THE EXPECTED MID-LEVEL PATTERN AND THUS IS NOT THE PREFERRED
SOLUTION AT THIS TIME. FARTHER WEST, MID-LEVEL TROUGHING NEAR THE WEST COAST IS
EXPECTED TO FOSTER NEAR OR BELOW-NORMAL TEMPERATURES THERE. MEANWHILE, THE
STRONG MID-LEVEL TROUGHING WEST OF ALASKA FAVORS SUBNORMAL TEMPERATURES OVER
CENTRAL AND WESTERN PARTS OF THE STATE, WITH WARMER THAN NORMAL WEATHER FAVORED
IN SOUTHERLY FLOW OVER THE NORTHEASTERN MAINLAND. IN HAWAII, THE FLAT PATTERN
WITH SLIGHTLY ABOVE-NORMAL 500-HPA HEIGHTS FAVORS HIGHER THAN NORMAL
TEMPERATURES OVER THE ISLAND CHAIN, ESPECIALLY FROM OAHU NORTHWARD.
THE BIAS-CORRECTED AND REFORECAST PRECIPITATION TOOLS ARE NOT IN PARTICULARLY
GOOD AGREEMENT, BUT MID-LEVEL TROUGHING NEAR THE WEST COAST AND
CYCLONICALLY-CURVED MID-LEVEL FLOW REACHING FROM THERE TOWARD THE DEVELOPING
RIDGE IN CENTRAL NORTH AMERICA WOULD FAVOR SURPLUS PRECIPITATION IN THE PACIFIC
NORTHWEST AND, TO A LESSER EXTENT, DOWNSTREAM INTO THE NORTH-CENTRAL STATES AND
GREAT LAKES. IF THE INCREASED RAINFALL PANS OUT, IT SHOULD PROVE BENEFICIAL IN
HELPING REDUCE THE ELEVATED POTENTIAL FOR THE RAPID DEVELOPMENT AND SPREAD OF
WILDFIRES THAT HAVE BEEN AFFECTING A GOOD PORTION OF THE WEST. FARTHER SOUTH,
ABOVE-NORMAL 500-HPA HEIGHTS DOWNSTREAM FROM THE RIDGE AXIS ARE EXPECTED TO
BRING BELOW-NORMAL RAINFALL TO AREAS ALONG THE GULF COAST. THE RAW
ENSEMBLE-MEAN MODEL OUTPUTS ARE MUCH DRIER THAN THE REFORECAST TOOLS, BUT THE
MID-LEVEL PATTERN APPEARS MORE LIKELY TO FAVOR LESSER AMOUNTS AND THUS THE RAW
TOOLS ARE PREFERRED, WITH LESS EMPHASIS PLACED ON THE REFORECAST TOOLS. MODEL
OUTPUT AND DERIVED TOOLS ARE INCONSISTENT ALONG MOST OF THE EASTERN SEABOARD,
SO ODDS FAVOR NEITHER ABOVE- NOR BELOW-NORMAL PRECIPITATION IN THIS PART OF THE
CONUS. FARTHER NORTH, ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS MOST OF
ALASKA DOWNSTREAM FROM THE STRONG MID-LEVEL TROUGH, ESPECIALLY IN PARTS OF THE
NORTHWESTERN MAINLAND WHICH ARE CLOSEST TO THE TROUGH AXIS. ACROSS HAWAII, THE
CONSOLIDATION TOOL WAS FOLLOWED, WHICH SLIGHTLY FAVORS WETTER THAN NORMAL
WEATHER OVER THE CENTRAL AND EASTERN PARTS OF THE STATE, WITH AMOUNTS EXPECTED
TO BE CLOSER TO NORMAL OVER THE BIG ISLAND.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 15% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, 25% OF TODAY'S OPERATIONAL 0Z ECMWF 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: 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, HOW QUICKLY COOLER THAN NORMAL
TEMPERATURES ARE SCOURED OUT OF THE NORTH-CENTRAL CONUS, AND INCONSISTENCIES IN
PRECIPITATION GUIDANCE BETWEEN THE RAW ENSEMBLE MEAN OUTPUT AND THE REFORECAST
SOLUTIONS.
8-14 DAY OUTLOOK FOR AUG 14 - 20 2024
A TREND TOWARD MORE RIDGING IS FORECAST ACROSS THE CENTRAL AND INTERIOR WESTERN
CONUS DURING WEEK-2, WITH TROUGHING REMAINING NEAR BOTH COASTS. OVERALL,
500-HPA HEIGHTS SHOULD BE INCREASING THROUGHOUT THE CONUS AS THE WEEK
PROGRESSES, WITH ABOVE-NORMAL HEIGHTS COVERING ALMOST THE ENTIRE CONUS BY THE
END OF THE PERIOD. FARTHER NORTH, TROUGHING IS EXPECTED TO PERSIST WEST OF
ALASKA, WITH BELOW-NORMAL MEAN HEIGHTS EXTENDING EASTWARD, COVERING MOST OF THE
STATE. 500-HPA HEIGHTS SHOULD DECLINE SLIGHTLY AROUND HAWAII, PER THE ENSEMBLE
MEANS, LEAVING WEAK MID-LEVEL FLOW AND NEAR- TO SLIGHTLY BELOW-NORMAL HEIGHTS
ACROSS THE ISLAND CHAIN BY THE END OF THE PERIOD.
THE DERIVED TEMPERATURE TOOLS ARE NOT IN AS GOOD AGREEMENT WITH EACH OTHER AS
DURING THE 6- TO 10-DAY PERIOD, BUT THE MID-LEVEL RIDGING ESTABLISHED EARLY
CENTERED OVER THE CENTRAL OR INTERIOR WESTERN STATES FAVORS ABOVE-NORMAL
TEMPERATURES ACROSS MOST OF THE LOWER 48. THE WARM SIGNAL SHOWN BY THE TOOLS
WAS DOWNPLAYED SLIGHTLY ALONG THE SOUTHEAST COAST AND THE CENTRAL AND WESTERN
GULF COAST REGIONS DUE SOME ELEVATED POTENTIAL FOR TROPICAL CYCLONE DEVELOPMENT
NEARBY, WHICH COULD AFFECT THESE AREAS WITH INCREASED CLOUD COVER AND
PRECIPITATION, THUS LOWERING TEMPERATURES. TO THE EAST AND WEST OF THE
MID-CONTINENTAL RIDGE, NEAR- OR BELOW-NORMAL TEMPERATURES SEEM MORE LIKELY
ACROSS WESTERN AND EASTERN PORTIONS OF THE CONUS. MEANWHILE, WITH THE MID-LEVEL
PATTERNS NEAR ALASKA AND HAWAII CHANGING LITTLE RELATIVE TO THE 6- TO 10-DAY
PERIOD, SUBNORMAL TEMPERATURES CONTINUE TO BE FAVORED FOR SOUTHERN, CENTRAL,
AND WESTERN ALASKA WITH WARMER THAN NORMAL WEATHER MORE LIKELY IN NORTHWESTERN
PARTS OF THE STATE, AND ACROSS HAWAII.
PRECIPITATION TOOLS WERE NOT IN PARTICULARLY GOOD AGREEMENT FOR THE WEEK-2
PERIOD. MORE SPECIFICALLY, THERE WAS DISAGREEMENT AMONG THE RAW ENSEMBLE MEAN
OUTPUT REGARDING PRECIPITATION ACROSS THE INTERIOR WEST, AND THE REFORECAST
TOOLS SIGNIFICANTLY DOWNPLAYED THE POTENTIAL FOR SUBNORMAL PRECIPITATION NEAR
THE GULF COAST. DUE TO THIS DISAGREEMENT, MOST LOCATIONS HAVE EITHER EQUAL
CHANCES OF RECORDING ABOVE, NEAR, OR BELOW PRECIPITATION, OR A SLIGHT TILT OF
THE ODDS IN ONE DIRECTION OR THE OTHER (BELOW 40 PERCENT). THE ONLY EXCEPTIONS
WERE IN WESTERN ALASKA, THE PACIFIC NORTHWEST, AND PART OF THE HIGH PLAINS,
WHERE TOOLS WERE IN BETTER AGREEMENT IN DEPICTING SURPLUS PRECIPITATION, WHICH
WAS ALSO CONSISTENT WITH THE ANTICIPATED 500-HPA HEIGHT PATTERN. ELSEWHERE,
SLIGHTLY ENHANCED CHANCES FOR WETTER THAN NORMAL CONDITIONS STRETCHED ALONG
MUCH OF THE NORTHERN TIER OF THE CONUS FROM THE NORTHWEST THROUGH THE UPPER
MISSISSIPPI AND OHIO VALLEYS, INTO LOWER NEW ENGLAND. THE DRIER SIGNAL IN THE
RAW TOOLS WAS FAVORED IN THE SOUTHEAST, LOWER MISSISSIPPI VALLEY, AND ADJACENT
SOUTHERN GREAT PLAINS WHICH IS MORE CONSISTENT WITH THE SYNOPTIC PATTERN, BUT
TEMPERED BY AN INCREASED CHANCE FOR TROPICAL CYCLONE DEVELOPMENT IN THE WESTERN
GULF AND IN THE ATLANTIC NEAR THE SOUTHEAST.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 30% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 35% 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 THE EVOLVING TROUGH-RIDGE-TROUGH PATTERN ACROSS NORTH
AMERICA, OFFSET BY LESSER AGREEMENT AMONG THE DERIVED TEMPERATURE AND
PRECIPITATION TOOLS, PARTICULARLY IN THE INTERIOR WEST AND NEAR THE GULF COAST.
CONDITIONS IN THE LATTER REGION ARE FURTHER COMPLICATED BY THE SOMEWHAT
ELEVATED POTENTIAL FOR TROPICAL CYCLONE DEVELOPMENT IN THE VICINITY.
FORECASTER: RICH TINKER
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:
19520802 - 19770815 - 20090728 - 19740730 - 19980719
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:
19520803 - 19770815 - 20090728 - 19990802 - 20090802
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 12 - 16 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF N N
SRN CALIF N N IDAHO N A NEVADA N N
W MONTANA A A E MONTANA N A WYOMING N A
UTAH A N ARIZONA A N COLORADO A A
NEW MEXICO A N N DAKOTA A A S DAKOTA N A
NEBRASKA A A KANSAS A N OKLAHOMA A N
N TEXAS A B S TEXAS A B W TEXAS A N
MINNESOTA N A IOWA N A MISSOURI A N
ARKANSAS A N LOUISIANA A B WISCONSIN N A
ILLINOIS N N MISSISSIPPI A B MICHIGAN N N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE A N ALABAMA A B NEW YORK B N
VERMONT B N NEW HAMP B N MAINE N N
MASS B N CONN B N RHODE IS B N
PENN B N NEW JERSEY B N W VIRGINIA B N
MARYLAND B N DELAWARE B N VIRGINIA B N
N CAROLINA B N S CAROLINA A N GEORGIA A B
FL PNHDL A B FL PENIN A B 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 14 - 20 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N A OREGON N A NRN CALIF B N
SRN CALIF B N IDAHO N N NEVADA N N
W MONTANA A A E MONTANA A A WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N 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 N
ARKANSAS A N LOUISIANA A N WISCONSIN A A
ILLINOIS A A MISSISSIPPI A B MICHIGAN A N
INDIANA A A OHIO A N KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS N N CONN B 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 N
FL PNHDL A B 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
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.
Main Text Page