803
FXUS06 KWBC 081902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT THU AUGUST 08 2024
6-10 DAY OUTLOOK FOR AUG 14 - 18 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.
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 AND
MID-ATLANTIC. BELOW-NORMAL HEIGHTS ARE PREDICTED ACROSS WESTERN ALASKA,
UNDERNEATH THE INFLUENCE OF TROUGHING WITH A -150 METER NEGATIVE HEIGHT ANOMALY
CENTER OVER THE BERING SEA. COMPARED TO YESTERDAY, THE 0Z GEFS AND ECENS DEPICT
A MORE NORTHWARD EXTENSION OF THE CENTRAL PACIFIC RIDGE, 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 DURING THE 6-10 DAY PERIOD. THE
HIGHEST PROBABILITIES (GREATER THAN 60 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 THE EASTERN SEABOARD. THE ECENS REFORECAST TOOL
HAS INCREASED ITS SIGNAL FOR BELOW-NORMAL TEMPERATURES IN THE EAST COMPARED TO
YESTERDAY, AND IS NOW MORE IN LINE WITH OTHER GUIDANCE. ANOMALOUS TROUGHING
OVER THE BERING SEA FAVORS INCREASED PROBABILITIES FOR BELOW-NORMAL
TEMPERATURES OVER MUCH OF ALASKA, EXCLUDING THE NORTHERN MAINLAND WHERE
ABOVE-NORMAL TEMPERATURES ARE FAVORED. 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. WEAK
PROBABILITIES FOR BELOW-NORMAL PRECIPITATION ARE HIGHLIGHTED OVER THE GREAT
LAKES AND NORTHERN NEW ENGLAND, FURTHER DISPLACED FROM THE PROJECTED STORM
TRACK AND CLOSER TO THE ANOMALOUS RIDGE CENTER OVER CANADA. BELOW-NORMAL
PRECIPITATION CHANCES ARE ALSO ELEVATED OVER THE SOUTH-CENTRAL CONUS, SUPPORTED
MAINLY BY THE UNCALIBRATED 0Z ECENS AND THE ANALOGUES. PROBABILITIES FOR
ABOVE-NORMAL PRECIPITATION ARE ALSO 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 IS FAVORED
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.
NEAR- TO BELOW-NORMAL PRECIPITATION PROBABILITIES ARE ENHANCED ACROSS EASTERN
AND SOUTHEAST ALASKA UNDERNEATH GREATER INFLUENCE FROM RIDGING OVER CANADA.
NEAR- TO BELOW-NORMAL PRECIPITATION IS ALSO FORECAST OVER HAWAII.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF TODAY'S OPERATIONAL 0Z GFS 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 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, DUE TO
GOOD DYNAMICAL MODEL AGREEMENT REGARDING THE MID-LEVEL PATTERN, OFFSET BY WEAK
SIGNALS IN THE PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR AUG 16 - 22 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, ALTHOUGH THESE FEATURES ARE SLIGHTLY MORE
AMPLIFIED IN THE WEEK-2 MANUAL HEIGHT BLEND COMPARED TO YESTERDAY INDICATING
MORE PERSISTENCE. 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 ROCKIES, NORTHERN PLAINS, AND UPPER
MISSISSIPPI VALLEY. TROUGHING OVER THE BERING SEA IS FORECAST TO LIFT OUT EARLY
IN WEEK-2 WITH A MORE ZONALLY ORIENTED FLOW PATTERN DEVELOPING OVER ALASKA AS
RIDGING OVER THE CENTRAL PACIFIC EXTENDS NORTHWARD. THIS FAVORS NEAR- TO
ABOVE-NORMAL HEIGHTS ACROSS SOUTHERN AND EASTERN ALASKA IN THE MANUAL BLEND.
BELOW NORMAL HEIGHTS REMAIN FORECAST ACROSS THE WESTERN MAINLAND WITH A -90
METER NEGATIVE HEIGHT ANOMALY CENTER OVER THE BERING SEA. ABOVE-NORMAL HEIGHTS
ARE PREDICTED ACROSS HAWAII.
EXPANDING RIDGING SUPPORTS INCREASED CHANCES FOR ABOVE-NORMAL TEMPERATURES OVER
MUCH OF THE 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 INTO SOUTHERN NEW ENGLAND,
LINGERING WEAK TROUGHING COMBINED WITH SATURATED GROUND FAVORS TEMPERATURES
CLOSER TO NORMAL, WITH LARGER POSITIVE HEIGHT ANOMALIES FAVORING ABOVE-NORMAL
TEMPERATURES ACROSS NORTHERN NEW ENGLAND. THE GEFS AND CMCE REFORECAST TOOLS
HAVE EXPANDED THE SIGNAL FOR BELOW-NORMAL TEMPERATURES ON THE EAST COAST
COMPARED TO YESTERDAY, AND ALTHOUGH THE ECENS REFORECAST TOOL IS STILL ON THE
WARMER SIDE, THE MORE PERSISTENT TROUGHING PATTERN FAVORS A SLIGHT TILT TOWARD
INCREASED BELOW-NORMAL TEMPERATURE PROBABILITIES OVER THE COASTAL MID-ATLANTIC.
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 SOUTHWESTERN
ALASKA TIED TO TROUGHING EARLY IN THE PERIOD, WITH ABOVE-NORMAL TEMPERATURE
PROBABILITIES INCREASED OVER EASTERN ALASKA CONSISTENT WITH MORE RIDGING
BUILDING FROM THE CENTRAL PACIFIC. ABOVE-NORMAL TEMPERATURES ARE FORECAST
ACROSS HAWAII SUPPORTED BY THE REFORECAST CONSOLIDATION TOOL.
ABOVE-NORMAL PRECIPITATION PROBABILITIES REMAIN ELEVATED OVER MUCH OF THE
NORTHWEST, ROCKIES, AND NORTHERN PLAINS THROUGHOUT WEEK-2, WITH NEAR- TO
BELOW-NORMAL PRECIPITATION CHANCES ELEVATED OVER PORTIONS OF THE GREAT BASIN.
FORECAST TOOLS OFFER MIXED SIGNALS ACROSS THE MIDWEST, WITH THE ECENS (GEFS)
REFORECAST TOOL DEPICTING HIGHER CHANCES FOR ABOVE (BELOW) NORMAL
PRECIPITATION. THE ACTIVE STORM TRACK DISCUSSED IN THE 6-10 DAY PERIOD IS
LIKELY TO PERSIST, ALTHOUGH MORE RIDGING WOULD SUPPORT RELATIVELY DRIER
CONDITIONS. THEREFORE, NEAR-NORMAL PRECIPITATION IS FORECAST OVER MUCH OF THE
MIDWEST. THE DRIER UNCALIBRATED TOOLS AND ANALOGUES ARE PREFERRED ACROSS THE
SOUTH-CENTRAL CONUS, WITH BELOW-NORMAL PRECIPITATION PROBABILITIES INCREASED
CLOSER TO THE RIDGE AXIS. CONTINUED FRONTAL ACTIVITY IN THE EAST SLIGHTLY
ENHANCES THE ODDS FOR ABOVE-NORMAL PRECIPITATION. THE NATIONAL HURRICANE CENTER
CONTINUES TO MONITOR A TROPICAL DISTURBANCE OVER THE MAIN DEVELOPMENT REGION OF
THE ATLANTIC. MANY ENSEMBLE SOLUTIONS INDICATE A RECURVING TRACK ACROSS THE
WESTERN ATLANTIC AND A MORE WESTWARD TRACK COULD RESULT IN AN ENHANCEMENT OF
PRECIPITATION ALONG THE EAST COAST DURING WEEK-2. NEAR- TO ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE INCREASED OVER MUCH OF ALASKA UNDERNEATH
ENHANCED WESTERLY MID-LEVEL FLOW, EXCLUDING SOUTHEAST ALASKA WHERE NEAR- TO
BELOW-NORMAL PRECIPITATION IS FAVORED. NEAR- TO BELOW-NORMAL PRECIPITATION
CHANCES REMAIN ELEVATED OVER HAWAII.
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 BROADENING RIDGING OVER THE CENTRAL CONUS, OFFSET BY
CONTINUED WEAK SIGNALS IN THE PRECIPITATION TOOLS AND UNCERTAINTY IN THE
TROPICS.
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:
20090728 - 19520804 - 19580821 - 19990802 - 19600805
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 - 19530802 - 19990804 - 19880821 - 19520804
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 14 - 18 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 N B
W MONTANA A 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 A MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS N A MISSISSIPPI A B MICHIGAN A B
INDIANA N N OHIO N N KENTUCKY N A
TENNESSEE N N ALABAMA A N NEW YORK N N
VERMONT A N NEW HAMP A N 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 N N
FL PNHDL A N FL PENIN A A AK N SLOPE A A
AK ALEUTIAN B A AK WESTERN B A AK INT BSN N A
AK S INT B A AK SO COAST B A AK PNHDL N N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 16 - 22 2024
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A A OREGON N A NRN CALIF B N
SRN CALIF B N IDAHO A A NEVADA A B
W MONTANA A A E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A N N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A N OKLAHOMA A B
N TEXAS A B S TEXAS A N W TEXAS A B
MINNESOTA A N IOWA A N MISSOURI A N
ARKANSAS A B LOUISIANA A B WISCONSIN A N
ILLINOIS A N MISSISSIPPI A B MICHIGAN A N
INDIANA A N OHIO A N KENTUCKY A N
TENNESSEE A N 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 N NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE B A VIRGINIA N A
N CAROLINA N A S CAROLINA N A GEORGIA A N
FL PNHDL A N FL PENIN A A 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 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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