921
FXUS06 KWBC 091947
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT TUE JULY 09 2024
6-10 DAY OUTLOOK FOR JUL 15 - 19 2024
DYNAMICAL MODELS HAVE COME INTO BETTER AGREEMENT ON THE MID-LEVEL HEIGHT
PATTERN TODAY, BUT SOME DISAGREEMENT REMAINS. ALL MODELS PUT A MAXIMUM 500-HPA
HEIGHT ANOMALY IN SOUTHWESTERN CANADA OR THE ADJACENT NORTHERN ROCKIES OR
INTERMOUNTAIN WEST, WITH POSITIVE ANOMALIES EXTENDING ACROSS THE NORTHERN TIER
OF THE CONTIGUOUS UNITED STATES (CONUS) AND LESSER ANOMALIES FARTHER SOUTH. THE
GEFS, OPERATIONAL GFS, AND OPERATIONAL EUROPEAN MODELS DEPICT BELOW-NORMAL
500-HPA HEIGHTS OVER PART OF THE SOUTHWESTERN CONUS WHILE THE EUROPEAN AND
CANADIAN ENSEMBLE MEANS KEEP MID-LEVEL HEIGHTS ABOVE-NORMAL THERE.
TELECONNECTIONS RELATIVE TO THE MID-LEVEL HEIGHT ANOMALY CENTER IN OR NEAR
SOUTHWEST CANADA FAVOR ABOVE-NORMAL HEIGHTS IN THIS SOUTHWEST, SO THE FORECAST
LEANED MORE TOWARD GUIDANCE FROM THE EUROPEAN AND CANADIAN ENSEMBLES. THIS
RESULTS IN A FAIRLY STRONG MEAN MID-LEVEL RIDGE OVER THE WESTERN CONUS, WITH A
CLOSED CIRCULATION POSSIBLE NEAR THE FOUR CORNERS REGION. DOWNSTREAM, THERE IS
A WEAK MID-LEVEL TROUGH OVER THE EASTERN CONUS RELATIVE TO THE WESTERN
MID-LEVEL RIDGE, EVEN THOUGH 500-HPA HEIGHTS ARE A LITTLE ABOVE NORMAL THERE IN
ALL DYNAMICAL MODELS. IN ALASKA, THERE IS GOOD AGREEMENT FOR NEGATIVE 500-HPA
HEIGHT ANOMALIES AND TROUGHING TO CONTINUE THROUGH THE PERIOD, WITH THE
NEGATIVE HEIGHT ANOMALIES MOST PRONOUNCED OVER SOUTHERN PARTS OF THE MAINLAND.
HAWAII IS FORECAST TO SEE NEAR TO SLIGHTLY ABOVE-NORMAL 500-HPA HEIGHTS, WITH A
POSITIVE ANOMALY CENTER SITTING NORTHWEST OF THE STATE. .
THIS PATTERN FAVORS ABOVE-NORMAL TEMPERATURES FOR NEARLY THE ENTIRE CONUS AND
HAWAII DURING THE 6-10 DAY PERIOD. THE STRONGEST CHANCES FOR ABOVE-NORMAL
TEMPERATURES ARE IN THE SOUTHEAST AND THE NORTHERN INTERMOUNTAIN WEST, WHERE
PROBABILITIES EXCEED 70 PERCENT. THE ONLY AREAS WITHOUT ENHANCED ODDS FOR
WARMER THAN NORMAL WEATHER ARE THE NORTHERN GREAT LAKES, PART OF THE SOUTHWEST,
AND ALONG PART OF THE PACIFIC COAST. THE NORTHERN GREAT LAKES WILL BE CLOSEST
TO THE EASTERN NORTH AMERICAN TROUGH, SURPLUS RAINFALL SHOULD KEEP THE HEAT IN
CHECK IN THE SOUTHWEST, AND STRONG NORTHERLY OR ONSHORE SURFACE WINDS WILL
MODERATE TEMPERATURE ALONG PARTS OF THE WEST COAST, ESPECIALLY THE PACIFIC
NORTHWEST. IN CONTRAST, THE STRONG MID-LEVEL TROUGHING OVER ALASKA BRINGS
ENHANCED CHANCES FOR BELOW-NORMAL TEMPERATURES TO THE ENTIRE STATE, WITH THE
HIGHEST LIKELIHOODS (OVER 60 PERCENT) IN PARTS OF THE SOUTHERN MAINLAND CLOSEST
WHERE NEGATIVE MID-LEVEL HEIGHT ANOMALIES ARE THE GREATEST. WITH 500-HPA
HEIGHTS MUCH CLOSER TO NORMAL, THERE IS ONLY A SLIGHTLY ELEVATED CHANCE FOR
WARMER THAN NORMAL CONDITIONS ACROSS HAWAII.
ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS PORTIONS OF THE EASTERN CONUS
DURING THE 6-10 DAY PERIOD. RAW OUTPUT FROM THE ENSEMBLES ALL SHOW AT LEAST
SLIGHTLY ENHANCED CHANCES FOR WETTER THAN NORMAL WEATHER HERE, AS DOES THE
EUROPEAN REFORECAST TOOL. THE GEFS AND CANADIAN ENSEMBLE REFORECASTS TOOLS SHOW
LESS FAVORABLE CONDITIONS FOR ABOVE-NORMAL RAINFALL, BUT SINCE THE EUROPEAN
ENSEMBLE MEANS ARE CLOSE TO THE EXPECTED 500-HPA PATTERN, THE PRECIPITATION
OUTLOOK LEANS TOWARD ITS RAW AND REFORECAST RAINFALL OUTPUT. ABOVE NORMAL
PRECIPITATION IS ALSO EXPECTED FROM THE GREAT PLAINS WESTWARD TO NEAR THE
NORTHERN ROCKIES, AND ACROSS THE CENTRAL AND SOUTHERN ROCKIES TO THE MIDDLE AND
LOWER INTERMOUNTAIN WEST. ALL OF THE REFORECAST TOOLS FAVOR HEAVIER THAN NORMAL
PRECIPITATION IN THIS REGION WHILE THE RAW ENSEMBLE MEAN OUTPUTS ARE HIGHLY
VARIABLE AND NOT AS CONSISTENT WITH THEIR OWN FORECAST MID-LEVEL PATTERNS. THE
CONSOLIDATION TOOL ALSO LEANS WET IN THIS REGION. THE GREATEST ODDS FOR HEAVIER
THAN NORMAL RAINFALL COVER THE DESERT SOUTHWEST, WHERE THE MID-LEVEL PATTERN
WOULD ENHANCE MONSOONAL RAINFALL, AND OVER CENTRAL AND WESTERN TEXAS, PRIMARILY
DUE TO THE EUROPEAN ENSEMBLE TOOLS SHOWING A STRONG INFLUX OF MOIST AIR AND
WELL ABOVE NORMAL RAINFALL. OVER THE REST OF THE CONUS, PRECIPITATION TOTALS
ARE EXPECTED TO BE CLOSER TO NORMAL, WITH SUBNORMAL TOTALS SLIGHTLY FAVORED
OVER THE NORTHERN ROCKIES, MUCH OF THE INTERMOUNTAIN WEST, AND A SMALL PART OF
THE CENTRAL GULF COAST. MOST OF THE GUIDANCE DERIVED FROM THE ENSEMBLES SHOW
ENHANCED ODDS FOR BELOW-NORMAL PRECIPITATION IN THESE AREAS. THERE ARE A FEW
OUTLIERS POINTING TOWARD HEAVIER RAINFALL, HOWEVER, AND THIS REDUCES FORECAST
CONFIDENCE. MEANWHILE, EXCESS PRECIPITATION IS SOMEWHAT FAVORED IN THE EASTERN
HALF OF ALASKA CLOSEST TO A MEAN SURFACE LOW PRESSURE CENTER, AND THE FORECAST
FOR HAWAII SHOWS WEAKLY INCREASED CHANCES FOR WETTER THAN NORMAL CONDITIONS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 50% OF TODAY'S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 15% OF TODAY'S OPERATIONAL 0Z ECMWF
CENTERED ON DAY 8, AND 35% 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. GOOD
AGREEMENT AMONG THE DYNAMICAL HEIGHT AND TEMPERATURE TOOLS IS OFFSET BY A WEAK
SUMMER PRECIPITATION PATTERN AND DIFFERENCES IN RAW AND REFORECAST MODEL
PRECIPITATION FORECASTS.
8-14 DAY OUTLOOK FOR JUL 17 - 23 2024
THE DYNAMIC MODELS ALL GENERALLY AGREE ON THE MID-LEVEL PATTERN FOR WEEK-2,
WHICH IS SIMILAR TO THE 6- TO 10-DAY PATTERN. ABOVE-NORMAL 500-HPA HEIGHTS
COVER THE ENTIRE CONUS, WITH THE LARGEST ANOMALIES IN NORTH-CENTRAL AND
NORTHWESTERN CONUS. THIS RESULTS IN A PATTERN FEATURING A WESTERN CONUS
MID-LEVEL RIDGE DRIFTING EASTWARD WITH A CLOSED CIRCULATION CENTER SOMEWHERE
OVER THE WEST, AND A SLIGHT MID-LEVEL THROUGH DOWNSTREAM IN EASTERN NORTH
AMERICA. DESPITE THE GOOD AGREEMENT ON THE MID-LEVEL PATTERN, HOWEVER, THE
DERIVED TEMPERATURE AND ESPECIALLY THE PRECIPITATION TOOLS ARE NOT AS
CONSISTENT WITH EACH OTHER. BELOW-NORMAL HEIGHTS INCREASE QUICKLY ACROSS
MAINLAND ALASKA AS A RIDGE BEGINS TO MOVE EASTWARD FROM THE ALEUTIANS, BUT
LOWER 500-HPA HEIGHTS PERSIST A LITTLE LONGER THAN IN YESTERDAY’S MODELS.
HAWAII REMAINS IN AN AREA WITH WEAK MID-LEVEL CIRCULATION AND NEAR- TO SLIGHTLY
ABOVE-NORMAL 500-HPA HEIGHTS.
ONCE AGAIN, MOST OF THE CONUS IS EXPECTED TO AVERAGE WARMER THAN NORMAL,
CONSISTENT WITH THE EXPECTED MID-LEVEL PATTERN AND BOTH THE RAW AND
BIAS-CORRECTED MEAN TEMPERATURES FROM THE ENSEMBLES. THE EUROPEAN AND CANADIAN
ENSEMBLE MEAN TEMPERATURE REFORECASTS SHOW A MUCH COOLER SOLUTION WITH NEAR OR
BELOW-NORMAL TEMPERATURES IN A SWATH FROM THE GREAT LAKES SOUTHWESTWARD ACROSS
THE SOUTHERN GREAT PLAINS. THIS GUIDANCE IS NOT IN LINE WITH MOST INDICATORS
AND DOES NOT SEEM LIKELY GIVEN THE 500-HPA HEIGHT PATTERN, SO THE WARMER
SOLUTIONS ARE FAVORED IN THIS FORECAST. ODDS FOR WARMTH EXCEED 70 PERCENT IN
THE NORTHERN ROCKIES CLOSE TO THE MID-LEVEL RIDGE AXIS, WITH 60 TO 70 PERCENT
CHANCES FOR WARMTH IN ADJACENT AREAS AS WELL AS SOUTHERN FLORIDA. THE ONLY
EXCEPTIONS ARE IN PART OF THE SOUTHWEST WHERE WETTER THAN NORMAL CONDITIONS MAY
REDUCE DAYTIME HEATING, AND IN THE NORTHWEST WHERE NORTHERLY TO ONSHORE SURFACE
FLOW SHOULD USHER IN SOMEWHAT COOLER CONDITIONS. THESE COOLING SURFACE WINDS
EASE SLOWLY WITH TIME, WHICH SHOULD ALLOW TEMPERATURES THERE TO SLOWLY RISE
ABOVE NORMAL SIMILAR TO THE INTERIOR WEST. IN ALASKA, SURFACE TEMPERATURES
SHOULD REMAIN BELOW NORMAL UNDERNEATH RISING BUT STILL BELOW-NORMAL MID-LEVEL
HEIGHTS, AND THE WEAK HEIGHT PATTERN ACROSS HAWAII AGAIN WEAKLY FAVORS
ABOVE-NORMAL TEMPERATURES THERE.
THE PRECIPITATION SIGNALS IN THE GUIDANCE CONTINUE TO BE WEAK AND MIXED ACROSS
MANY PORTIONS OF THE COUNTRY. THE STRONGEST CHANCES FOR ABOVE-NORMAL
PRECIPITATION ARE IN PORTIONS OF WESTERN TEXAS UNDER A SIGNIFICANT INFLUX OF
MOIST AIR FROM THE SOUTH, AND IN THE SOUTHEAST WHERE MODELS INDICATE A WEAK
STALLED FRONTAL SYSTEM COULD ENHANCE RAINFALL TOTALS. A VERY SLIGHT TILT OF THE
ODDS TOWARD WETTER THAN NORMAL CONDITIONS COVERS MOST OF THE SOUTHERN TIER OF
THE CONUS INTO PART OF THE MID-ATLANTIC REGION. FARTHER NORTH, UNDER MORE
PRONOUNCED MID-LEVEL HEIGHT ANOMALIES, NEAR- OR BELOW-NORMAL PRECIPITATION
SEEMS MORE LIKELY. MEANWHILE, ABOVE-NORMAL PRECIPITATION IS SLIGHTLY FAVORED IN
MOST OF ALASKA UNDER SUBNORMAL MID-LEVEL HEIGHTS AND A MEANDERING SURFACE LOW
PRESSURE CENTER, AND ALSO THOUGH HAWAII IN CONCERT WITH MOST OF THE TEMPERATURE
AND PRECIPITATION GUIDANCE.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY'S GFS
SUPERENSEMBLE MEAN CENTERED ON DAY 11, 45% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 30% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON
DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: ABOVE NORMAL, 4 OUT OF 5, WITH
GUIDANCE IN BETTER AGREEMENT ON THE MID-LEVEL HEIGHT PATTERN OFFSET BY
DIFFERENCES BETWEEN THE RAW, BIAS-CORRECTED, REFORECAST TOOLS, ESPECIALLY IN
THE TYPICALLY WEAK SUMMER PRECIPITATION PATTERN.
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
JULY 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:
19790717 - 20060623 - 19860721 - 19670701 - 19810718
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:
20060623 - 19790716 - 19670630 - 20060628 - 19940711
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 15 - 19 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A N
W MONTANA A B E MONTANA A N 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 A OKLAHOMA A N
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A N LOUISIANA A N WISCONSIN A N
ILLINOIS A N MISSISSIPPI A N MICHIGAN A A
INDIANA A N OHIO A A 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 A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE B A
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B A
AK S INT B A AK SO COAST B A AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 17 - 23 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A N NRN CALIF A N
SRN CALIF A A IDAHO A N NEVADA A N
W MONTANA A B E MONTANA A B WYOMING A N
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A A N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A A
N TEXAS A A S TEXAS A A W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A A LOUISIANA A A WISCONSIN A N
ILLINOIS A N MISSISSIPPI A A MICHIGAN A B
INDIANA A N OHIO A N KENTUCKY A A
TENNESSEE A A ALABAMA A A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A A CONN A A RHODE IS A A
PENN A N NEW JERSEY A A W VIRGINIA A A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A A FL PENIN A A AK N SLOPE B N
AK ALEUTIAN B N AK WESTERN B N AK INT BSN B N
AK S INT B N AK SO COAST B N 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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