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FXUS06 KWBC 091902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI AUGUST 09 2024
6-10 DAY OUTLOOK FOR AUG 15 - 19 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 ALONG THE
WEST COAST OF THE CONUS. BROAD RIDGING IS PREDICTED ACROSS THE CENTRAL CONUS,
WITH TROUGHING DOWNSTREAM OVER THE NORTHEASTERN U.S. AND NORTHWEST ATLANTIC.
THERE IS A SLIGHT RETROGRESSION OF THE RIDGE-TROUGH PATTERN ACROSS THE CENTRAL
AND EASTERN CONUS THROUGHOUT THE PERIOD. TODAY’S MANUAL HEIGHT BLEND DEPICTS
NEAR-NORMAL HEIGHTS OVER MOST OF THE CONUS, WITH SLIGHTLY ABOVE-NORMAL HEIGHTS
OVER PARTS OF THE NORTHERN PLAINS AND UPPER MISSISSIPPI VALLEY AND BELOW-NORMAL
HEIGHTS OVER THE NORTHEAST, MID-ATLANTIC, AND PACIFIC NORTHWEST. BELOW-NORMAL
HEIGHTS ARE PREDICTED ACROSS WESTERN ALASKA, UNDERNEATH THE INFLUENCE OF
TROUGHING WITH A -120 METER NEGATIVE HEIGHT ANOMALY CENTER OVER THE BERING SEA.
THE 0Z GEFS AND ECENS CONTINUE TO DEPICT MORE AMPLIFIED RIDGING TO THE SOUTH OF
ALASKA, RESULTING IN NEAR- TO ABOVE-NORMAL HEIGHTS ACROSS EASTERN ALASKA AND
ABOVE-NORMAL HEIGHTS OVER HAWAII.
THE EVOLVING MID-LEVEL PATTERN FAVORS ELEVATED PROBABILITIES OF ABOVE-NORMAL
TEMPERATURES OVER MOST OF THE INTERIOR CONUS, NORTHERN NEW ENGLAND, AND THE
SOUTHEAST 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 PARTS
OF THE EASTERN SEABOARD. ANOMALOUS TROUGHING OVER THE BERING SEA FAVORS
INCREASED PROBABILITIES FOR BELOW-NORMAL TEMPERATURES OVER MUCH OF ALASKA,
EXCLUDING PARTS OF THE NORTHERN AND EASTERN MAINLAND AND SOUTHEAST ALASKA WHERE
ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE ELEVATED. 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., AND EXTENDS TO THE EASTERN SEABOARD WHERE THE
WEAKNESS IN THE MID-LEVEL FLOW FAVORS INCREASED FRONTAL ACTIVITY. THE NATIONAL
HURRICANE CENTER CONTINUES TO MONITOR A TROPICAL DISTURBANCE OVER THE MAIN
DEVELOPMENT REGION OF THE ATLANTIC. MANY ENSEMBLE SOLUTIONS DEPICT A RECURVING
TRACK ACROSS THE WESTERN ATLANTIC, BUT A MORE WESTWARD TRACK COULD RESULT IN AN
ENHANCEMENT OF PRECIPITATION ALONG THE EAST COAST TOWARD THE END OF THE PERIOD.
BELOW-NORMAL PRECIPITATION CHANCES ARE ELEVATED OVER THE SOUTH-CENTRAL CONUS,
SUPPORTED MAINLY BY THE UNCALIBRATED 0Z ECENS AND THE ANALOGUES. PROBABILITIES
FOR ABOVE-NORMAL PRECIPITATION ARE 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 CHANCES ARE
ENHANCED ACROSS THE 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 MOST OF MAINLAND
ALASKA. BELOW-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED ACROSS SOUTHEAST
ALASKA UNDERNEATH GREATER INFLUENCE FROM RIDGING OVER CANADA. BELOW-NORMAL
PRECIPITATION IS ALSO FORECAST OVER HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN 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
25% 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 SOME
DISAGREEMENT IN THE PRECIPITATION TOOLS ACROSS THE MIDWEST ALONG WITH
UNCERTAINTY RELATED TO TROPICAL ACTIVITY.
8-14 DAY OUTLOOK FOR AUG 17 - 23 2024
DYNAMICAL MODELS CONTINUE TO FAVOR INCREASING 500-HPA HEIGHTS ACROSS THE CONUS
DURING WEEK-2, WITH A 594-DM RIDGE CENTER DEPICTED IN THE 0Z ECENS, GEFS, AND
CMCE OVER THE FOUR CORNERS REGION BY THE SECOND HALF 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. THE WEEK-2 MANUAL BLEND INDICATES NEAR- TO
ABOVE-NORMAL HEIGHTS OVER MOST OF THE CONUS, WITH THE LARGEST POSITIVE HEIGHT
ANOMALIES (GREATER THAN +30 METERS) OVER THE NORTHERN PLAINS AND UPPER
MISSISSIPPI VALLEY. TROUGHING OVER THE BERING SEA IS FORECAST TO LIFT OUT EARLY
IN WEEK-2 WITH RIDGING AND POSITIVE HEIGHT ANOMALIES BUILDING INTO PARTS OF
SOUTHERN ALASKA. THIS FAVORS NEAR- TO ABOVE-NORMAL HEIGHTS ACROSS SOUTHERN AND
EASTERN ALASKA IN THE WEEK-2 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 INTERIOR CONUS. PROBABILITIES EXCEED 60 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, OHIO VALLEY, AND
SOUTHERN NEW ENGLAND, LINGERING WEAK TROUGHING FAVORS TEMPERATURES CLOSER TO OR
SLIGHTLY BELOW-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 ABOVE-NORMAL TEMPERATURE PROBABILITIES INCREASED OVER NORTHEASTERN ALASKA.
ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS HAWAII SUPPORTED BY THE
REFORECAST CONSOLIDATION TOOL.
ABOVE-NORMAL PRECIPITATION PROBABILITIES REMAIN ELEVATED OVER PARTS OF THE
NORTHWEST, ROCKIES, AND NORTHERN PLAINS THROUGHOUT WEEK-2, WITH NEAR- TO
BELOW-NORMAL PRECIPITATION CHANCES ELEVATED OVER PORTIONS OF THE GREAT BASIN.
UNCALIBRATED GUIDANCE HAS COME INTO BETTER AGREEMENT COMPARED TO YESTERDAY
REGARDING INCREASED CHANCES FOR BELOW-NORMAL PRECIPITATION ACROSS THE CENTRAL
CONUS AND MIDWEST. LOWER PROBABILITIES ARE HIGHLIGHTED FARTHER NORTH DUE TO
LESS AGREEMENT FROM THE ECENS REFORECAST TOOL, BUT HIGHER PROBABILITIES
(GREATER THAN 40 PERCENT) ARE HIGHLIGHTED ACROSS THE SOUTHERN PLAINS AND LOWER
MISSISSIPPI VALLEY WHERE THERE IS BETTER AGREEMENT IN THE REFORECAST TOOLS AND
SUPPORT FROM THE ANALOGUES. CONTINUED FRONTAL ACTIVITY IN THE EAST SLIGHTLY
ENHANCES THE ODDS FOR ABOVE-NORMAL PRECIPITATION, WITH A CONTINUED MONITORING
OF TROPICS GIVEN THE POTENTIAL FOR A RECURVING SYSTEM OVER THE WESTERN ATLANTIC
IN THE EARLY TO MIDDLE PART OF THE PERIOD. NEAR- TO ABOVE-NORMAL PRECIPITATION
PROBABILITIES ARE INCREASED OVER MUCH OF ALASKA UNDERNEATH ENHANCED WESTERLY
MID-LEVEL FLOW. BELOW-NORMAL PRECIPITATION CHANCES REMAIN ELEVATED OVER HAWAII.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 35% 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 AVERAGE, 4 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT REGARDING BROADENING RIDGING OVER THE CENTRAL CONUS AND
MORE CONSISTENCY IN THE PRECIPITATION FORECAST COMPARED TO YESTERDAY, BUT WITH
ADDED UNCERTAINTY DUE TO POTENTIAL TROPICAL ACTIVITY.
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:
20090729 - 19660821 - 19600805 - 19630823 - 19530805
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:
20090728 - 19660821 - 19880822 - 19530804 - 19630822
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 15 - 19 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B N
SRN CALIF B N IDAHO N A NEVADA B B
W MONTANA N 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 A KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A N
INDIANA A A OHIO N A KENTUCKY N A
TENNESSEE A A ALABAMA A N NEW YORK A A
VERMONT A A NEW HAMP A A MAINE A N
MASS N A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B 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 A A
AK S INT B A AK SO COAST B A AK PNHDL N B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 17 - 23 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B A OREGON B A NRN CALIF B N
SRN CALIF B N IDAHO A A NEVADA A N
W MONTANA A A E MONTANA A N WYOMING A A
UTAH A A ARIZONA A A COLORADO A A
NEW MEXICO A N N DAKOTA A N S DAKOTA A N
NEBRASKA A B KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A B IOWA A B MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A B
ILLINOIS A B MISSISSIPPI A B MICHIGAN A B
INDIANA A B OHIO N N KENTUCKY N N
TENNESSEE N B ALABAMA A B 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 N A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA N N S CAROLINA N N GEORGIA N N
FL PNHDL A N FL PENIN A A 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 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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