918
FXUS06 KWBC 181902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU JULY 18 2024
6-10 DAY OUTLOOK FOR JUL 24 - 28 2024
THE MID-LEVEL HEIGHT PATTERN ACROSS NORTH AMERICA AND THE SURROUNDING REGIONS
IS BEGINNING TO EVOLVE INTO A MORE ZONAL FLOW PATTERN ACROSS MUCH OF THE
CONTIGUOUS U.S. (CONUS). A MID-LEVEL RIDGE IS FORECAST OVER MUCH OF THE WESTERN
CONTIGUOUS U.S. (CONUS) TO DEAMPLIFY DURING THE PERIOD. A SHORTWAVE TROUGH THAT
HAS BEEN FORECAST OVER THE GULF OF ALASKA AND INTO THE PACIFIC NORTHWEST IS
MORE ROBUST TODAY BRINGING NEGATIVE ANOMALIES AND WEAK TROUGHING ALONG MUCH OF
THE WEST COAST. MEANWHILE, A STAGNANT POSITIVELY TILTED TROUGH ACROSS THE
CENTRAL CONUS ALSO FINALLY APPEARS TO BE FILLING IN BY THE END OF THE PERIOD.
THE ECENS, GEFS, AND CMCE ARE ALL IN AGREEMENT FOR AN AREA OF POSITIVE 500-HPA
HEIGHT ANOMALIES AND ASSOCIATED RIDGING TO DEVELOP ACROSS THE UPPER-MIDWEST AND
GREAT LAKES BY THE END OF THE PERIOD. IN THE WESTERN ATLANTIC OCEAN, WEAK
POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST. OVER ALASKA, POSITIVE MID-LEVEL
HEIGHT ANOMALIES ARE FORECAST AT THE ONSET OF THE PERIOD; HOWEVER, GUIDANCE IS
SUGGESTING A PATTERN CHANGE MAY OCCUR AT THE END OF THE PERIOD, BRINGING
BELOW-NORMAL 500-HPA HEIGHTS TO MUCH OF ALASKA. NEAR-NORMAL 500-HPA HEIGHTS ARE
FORECAST FOR HAWAII.
THE 6-10 DAY TEMPERATURE PATTERN FAVORS ABOVE-NORMAL TEMPERATURES ACROSS THE
INTERIOR WEST ASSOCIATED WITH MID-LEVEL RIDGING PARTICULARLY EARLY IN THE
PERIOD. A SHORTWAVE TROUGH IN THE GULF OF ALASKA AND BRITISH COLUMBIA IS
FORECAST TO BE DEEPER RELATIVE TO PRIOR FORECASTS AND MAY BRING NEAR TO
BELOW-NORMAL TEMPERATURES TO PORTIONS OF THE PACIFIC NORTHWEST AND NORTHERN
CALIFORNIA. BELOW-NORMAL TEMPERATURES ARE LIKELY ACROSS THE SOUTH-CENTRAL CONUS
AND ARE ASSOCIATED WITH A POSITIVELY TILTED TROUGH ACROSS THE CENTRAL CONUS.
MID-LEVEL HEIGHTS ARE FORECAST TO INCREASE ACROSS THE GREAT LAKES AND NORTHEAST
INCREASING CHANCES FOR ABOVE-NORMAL TEMPERATURES ACROSS THESE REGIONS. THROUGH
THE MID-ATLANTIC AND SOUTHERN ATLANTIC STATES THERE REMAINS SOME DISAGREEMENT
IN THE EVOLUTION OF THE MID-LEVEL HEIGHT PATTERN WITH SOME TOOLS SUGGESTING
STRONGER CHANCES FOR ABOVE-NORMAL TEMPERATURES WITH OTHERS FORECASTING
NEAR-NORMAL TEMPERATURES, THUS A SLIGHT TILT TOWARDS ABOVE-NORMAL TEMPERATURES
IS FORECAST. IN ALASKA, ABOVE-NORMAL TEMPERATURES ARE GENERALLY FAVORED ACROSS
THE EASTERN MAINLAND WITH BETTER AGREEMENT AMONG THE TOOLS FOR A PATTERN CHANGE
TO OCCUR DURING THE PERIOD. NEAR TO BELOW-NORMAL TEMPERATURES ARE NOW FAVORED
ACROSS PORTIONS OF THE WESTERN MAINLAND ALONG WITH THE PREVIOUS FORECAST
BELOW-NORMAL TEMPERATURES IN SOUTHEAST ALASKA AND THE ALEUTIAN ISLANDS. IN
HAWAII, ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR THE WESTERN PORTIONS OF THE
STATE WHILE NEAR-NORMAL TEMPERATURES ARE FAVORED FURTHER EAST CONSISTENT WITH
THE DYNAMICAL TOOLS
THE 6-10 DAY OUTLOOK FAVORS ABOVE-NORMAL PRECIPITATION ACROSS MUCH OF THE
EASTERN CONUS AND SOUTHWEST. IN THE SOUTHWEST, THERE CONTINUES TO BE INCREASED
CHANCES FOR ABOVE-NORMAL PRECIPITATION ASSOCIATED WITH MONSOON ACTIVITY WITH
SURFACE HIGH PRESSURE SITUATED OVER THE FOUR CORNERS REGION PROMOTING MOISTURE
ADVECTION INTO THE REGION. A STRONGER, RELATIVE TO YESTERDAY, MID-LEVEL TROUGH
ACROSS THE WEST MAY HELP TO PROMOTE UNSETTLED WEATHER FURTHER NORTH INTO
PORTIONS OF GREAT BASIN INCREASING CHANCES FOR ABOVE-NORMAL PRECIPITATION IN
PORTIONS OF NEVADA, UTAH, AND SOUTHERN IDAHO. FURTHER EAST, A TROUGH AND
ASSOCIATED STALLED FRONTAL BOUNDARY INCREASE CHANCES FOR ABOVE-NORMAL
PRECIPITATION FROM TEXAS THROUGH MUCH OF THE EASTERN CONUS. ACROSS THE NORTHERN
PLAINS AND PARTS OF THE NORTHERN ROCKIES, BELOW-NORMAL PRECIPITATION IS FAVORED
BENEATH MID-LEVEL RIDGING. IN ALASKA, ABOVE-NORMAL PRECIPITATION IS GENERALLY
FAVORED ACROSS MUCH OF THE STATE WITH CONTINUED CHANCES OF UNSETTLED WEATHER.
IN HAWAII, NEAR-NORMAL PRECIPITATION IS FAVORED CONSISTENT WITH WEAK SIGNALS
AND MIXED GUIDANCE.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 30% OF TODAY'S 6Z 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: ABOVE-AVERAGE, 4 OUT OF 5. GOOD
AGREEMENT AMONG THE DYNAMICAL TOOLS IS OFFSET BY DIFFERENCES IN TEMPERATURE AND
PRECIPITATION PATTERNS ACROSS THE EASTERN CONUS.
8-14 DAY OUTLOOK FOR JUL 26 - AUG 01, 2024
DURING WEEK-2, A MID-LEVEL RIDGE ACROSS THE WEST IS BREAKING DOWN AS A
SHORTWAVE TROUGH IMPACTS THE REGION. DURING THE PERIOD 500-HPA HEIGHTS RISE
OVER THE NORTH-CENTRAL AND NORTHEASTERN CONUS. NEAR-NORMAL 500-HPA HEIGHT
ANOMALIES ARE FORECAST ACROSS THE SOUTHERN CONUS AS A MID-LEVEL TROUGH FILLS IN
EARLY IN THE PERIOD. WEAK TROUGHING IS FORECAST ALONG THE WEST COAST. IN
ALASKA, A PATTERN SHIFT IS OCCURRING FROM THE 6-10 DAY PERIOD INTO THE WEEK-2.
POSITIVE MID-LEVEL HEIGHT ANOMALIES IN THE 6-10 DAY PERIOD, GIVE WAY TO
BELOW-NORMAL HEIGHTS ACROSS MUCH OF ALASKA FOR WEEK-2. THERE IS BETTER
AGREEMENT AMONG THE DYNAMICAL TOOLS FOR THIS PATTERN CHANGE TO TAKE HOLD EARLY
IN THE WEEK-2 PERIOD. HOWEVER, THE TROUGH FORECAST BY THE ECENS IS SLIGHTLY
LESS AMPLIFIED RELATIVE TO YESTERDAY’S FORECAST, SOMEWHAT INCREASING
UNCERTAINTY IN THE MID-LEVEL HEIGHT REGIME BY THE MIDDLE AND END OF THE PERIOD.
THEREFORE, THE WEEK-2 MEAN 500-HPA HEIGHTS FOR MOST OF ALASKA SHOW NEGATIVE
500-HPA HEIGHT ANOMALIES AND A WEAK TROUGH. OVER THE ALEUTIAN ISLANDS POSITIVE
500-HPA HEIGHTS ARE FAVORED. IN HAWAII, NEAR-NORMAL HEIGHTS REMAIN FORECAST FOR
THE STATE.
THE WEEK-2 TEMPERATURE OUTLOOK MAINTAINS ELEVATED CHANCES FOR ABOVE-NORMAL
TEMPERATURES ACROSS THE NORTHERN PLAINS STRETCHING BACK THROUGH THE INTERIOR
WEST AND INTO THE FOUR CORNERS BENEATH A MID-LEVEL RIDGE. AS THE PERIOD
PROGRESSES, ABOVE-NORMAL 500-HPA HEIGHTS ARE FORECAST TO CONTINUE TO STRENGTHEN
IN THE GREAT LAKES AND NORTHEAST LEADING TO ELEVATED ABOVE-NORMAL TEMPERATURE
CHANCES FOR THE WEEK-2 PERIOD ACROSS THESE REGIONS. A TROUGH FORECAST ACROSS
THE CENTRAL CONUS IN THE 6-10 DAY PERIOD, BEGINS TO WASH OUT BY THE MIDDLE TO
END OF WEEK-2. THEREFORE, ELEVATED BELOW-NORMAL TEMPERATURE CHANCES REMAIN BUT
ARE REDUCED RELATIVE TO THE 6-10 DAY PERIOD. STRONGLY ABOVE-NORMAL TEMPERATURE
CHANCES REMAIN FORECAST ACROSS FLORIDA BENEATH MID-LEVEL SUB-TROPICAL RIDGING.
FOR MAINLAND ALASKA, GUIDANCE IS IN BETTER AGREEMENT FOR A PATTERN TRANSITION
TO OCCUR EARLY IN THE WEEK-2 PERIOD. THEREFORE, THERE IS A SIGNIFICANT COOLING
TREND SEEN RELATIVE TO THE 6-10 DAY PERIOD ACROSS THE STATE. HOWEVER, THESE
CHANGES ARE JUSTIFIED DUE TO THE RAPID TRANSITION TO BELOW-NORMAL HEIGHTS AND
GOOD AGREEMENT AMONG THE DYNAMICAL TOOLS FOR BELOW-NORMAL TEMPERATURES TO
BECOME ESTABLISHED ACROSS ALASKA DURING WEEK-2. IN HAWAII, NEAR-NORMAL
TEMPERATURES ARE FAVORED WITH WEAK SIGNALS AMONG THE VARIOUS DYNAMICAL TOOLS.
ABOVE-NORMAL PRECIPITATION REMAINS FAVORED FOR MUCH OF THE AREAS EAST OF THE
MISSISSIPPI RIVER EXTENDING INTO THE SOUTHERN PLAINS. THESE ENHANCED CHANCES
FOR ABOVE-NORMAL PRECIPITATION ARE ASSOCIATED WITH A MID-LEVEL TROUGH EARLY IN
THE WEEK-2 PERIOD. NEAR TO BELOW-NORMAL PRECIPITATION IS FAVORED IN PORTIONS OF
THE NORTHERN AND CENTRAL PLAINS BENEATH POSITIVE 500-HPA HEIGHT ANOMALIES AND A
MID-LEVEL RIDGE. IN THE SOUTHWEST, WEAK SURFACE HIGH PRESSURE IS FORECAST
LEADING TO REDUCED CHANCES FOR MONSOON MOISTURE ADVECTION INTO THE REGION.
THEREFORE, NEAR TO BELOW-NORMAL PRECIPITATION IS FAVORED IN THESE AREAS TODAY.
FURTHER NORTH, PRECIPITATION CLIMATOLOGY REMAINS LOW DURING THIS TIME OF YEAR
BUT THE GUIDANCE IS LEANING TOWARDS ABOVE-NORMAL PRECIPITATION ACROSS THE
REGION. THE SLIGHTLY MORE ENHANCED TROUGH ACROSS THE WEST RELATIVE TO YESTERDAY
MAY HELP TO PROMOTE PRECIPITATION ACROSS THE NORTHWESTERN CONUS. IN ALASKA,
ABOVE-NORMAL PRECIPITATION REMAINS THE FAVORED OUTCOME ACROSS THE STATE WITH
CONTINUED CHANCES FOR UNSETTLED WEATHER AS FORECAST BY NEARLY ALL OF THE
DYNAMICAL MODEL TOOLS. IN HAWAII, ABOVE-NORMAL PRECIPITATION IS FAVORED ACROSS
MUCH OF THE STATE EXCLUDING THE BIG ISLAND CONSISTENT WITH THE TOOLS.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 10% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 6Z 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, GOOD
AGREEMENT AMONG THE TOOLS OFFSET BY A LESS AMPLIFIED AND TRANSITORY HEIGHT
PATTERN.
FORECASTER: RYAN BOLT
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:
20080630 - 19980707 - 19940721 - 19900710 - 19910731
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:
19940722 - 19980707 - 19530710 - 20080630 - 19960727
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 24 - 28 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON N N NRN CALIF A N
SRN CALIF A N IDAHO A N NEVADA A A
W MONTANA A B E MONTANA A B WYOMING A B
UTAH A N ARIZONA A A COLORADO A N
NEW MEXICO N A N DAKOTA A B S DAKOTA A B
NEBRASKA A B KANSAS B N OKLAHOMA B A
N TEXAS B A S TEXAS B A W TEXAS B A
MINNESOTA A N IOWA N N MISSOURI B A
ARKANSAS B A LOUISIANA B A WISCONSIN A N
ILLINOIS B A MISSISSIPPI B A MICHIGAN A A
INDIANA N A OHIO N A KENTUCKY B A
TENNESSEE B A ALABAMA B A NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A N
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A A W VIRGINIA N A
MARYLAND A A DELAWARE A A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA B A
FL PNHDL A A FL PENIN A A AK N SLOPE N A
AK ALEUTIAN B N AK WESTERN B A AK INT BSN A A
AK S INT N A AK SO COAST B N AK PNHDL B A
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 26 - AUG 01, 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON N A NRN CALIF N N
SRN CALIF N N IDAHO N A NEVADA A N
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA N A
N TEXAS B A S TEXAS B A W TEXAS A A
MINNESOTA A N IOWA A N MISSOURI N A
ARKANSAS B A LOUISIANA N A WISCONSIN A A
ILLINOIS A A MISSISSIPPI N A MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY N A
TENNESSEE N A ALABAMA N A NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A B
MASS A N CONN A N RHODE IS A N
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 A AK INT BSN B A
AK S INT B A AK SO COAST B N AK PNHDL B A
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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