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FXUS06 KWBC 201902
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 20 2023
6-10 DAY OUTLOOK FOR JUL 26 - 30 2023
MODEL SOLUTIONS REMAIN IN GOOD AGREEMENT AND CONSISTENT THAT THE PERSISTENT
ANOMALOUS 500-HPA RIDGE, INITIALLY OVER THE WESTERN AND SOUTHERN CONUS, EXPANDS
NORTHEASTWARD DURING LATE JULY. THIS WOULD LEAD TO A WARMING TREND ACROSS THE
MIDWEST, NORTHEAST, AND MID-ATLANTIC NEXT WEEK. FOR THESE AREAS, THE ENSEMBLE
MEANS HAVE CONVERGED ON A COMMON SOLUTION WITH POSITIVE 500-HPA HEIGHT
DEPARTURES PEAKING TO MORE THAN 60 METERS EACH DAY, FROM JULY 26 TO 28.
HOWEVER, BY JULY 30, THE ENSEMBLE MEANS DEPICT AN AMPLIFYING TROUGH OVER
SOUTHEASTERN CANADA WITH DECREASING 500-HPA HEIGHTS ACROSS THE GREAT LAKES AND
NORTHEAST. THE EXPANSIVE AND ANOMALOUS 500-HPA RIDGE FAVORS ABOVE-NORMAL
TEMPERATURES FOR MOST OF THE LOWER 48 STATES WITH A LARGE SPATIAL EXTENT OF 70
PERCENT PROBABILITIES AND EVEN A 80 PERCENT CHANCE ACROSS THE CENTRAL GREAT
PLAINS AND MIDDLE MISSISSIPPI VALLEY.
THE EXPANDING RIDGE WITH RISING 500-HEIGHTS IS LIKELY TO SUPPRESS SUMMER
CONVECTION ACROSS THE SOUTHERN TIER OF THE CENTRAL AND EASTERN CONUS. FARTHER
TO THE NORTH AND CLOSER TO THE MID-LEVEL WESTERLIES, NEAR NORMAL PRECIPITATION
AMOUNTS OR A SLIGHT LEAN TOWARDS ABOVE-NORMAL PRECIPITATION IS FORECAST FOR THE
NORTHERN GREAT PLAINS, GREAT LAKES, AND NORTHEAST. THE 500-HPA RIDGE AXIS IS
FORECAST TO BE CENTERED ACROSS THE FOUR CORNERS REGION, A FAVORABLE LOCATION
FOR AN ENHANCED MONSOON. HOWEVER, THE STRENGTH OF THE RIDGING ALOFT MAY OFFSET
THE FAVORABLE MONSOON CIRCULATION PATTERN. NEAR NORMAL PRECIPITATION AMOUNTS
ARE FORECAST FOR MUCH OF THE SOUTHWEST WITH SLIGHTLY ELEVATED ABOVE-NORMAL
PRECIPITATION PROBABILITIES LIMITED TO SOUTHWESTERN ARIZONA AND SOUTHEASTERN
CALIFORNIA. FARTHER TO THE NORTH ACROSS THE INTERMOUNTAIN WEST AND INTERIOR
PARTS OF THE PACIFIC NORTHWEST, TOOLS ARE LEANING TOWARDS BELOW-NORMAL
PRECIPITATION.
INCREASED ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE FORECAST FOR NEARLY ALL OF
ALASKA DUE TO THE POSITIVE 500-HPA HEIGHT ANOMALIES, BUT NEAR NORMAL
TEMPERATURES ARE FAVORED FOR PARTS OF SOUTHEASTERN ALASKA, COASTAL WESTERN
ALASKA, AND THE ALEUTIANS CLOSER TO A COUPLE OF TROUGHS. DOWNSTREAM OF A TROUGH
OVER THE BERING SEA, INCREASED CHANCES OF ABOVE-NORMAL PRECIPITATION ARE
FORECAST FOR MUCH OF MAINLAND ALASKA. A BUILDING RIDGE NEARBY OVER THE HIGHER
LATITUDES OF WESTERN NORTH AMERICA FAVORS BELOW-NORMAL PRECIPITATION FOR PARTS
OF SOUTHEASTERN ALASKA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 35% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
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
MODEL AGREEMENT ON THE 500-HPA HEIGHT PATTERN AND TEMPERATURE TOOLS OFFSET BY
CONTINUED WEAK SIGNALS AMONG THE PRECIPITATION TOOLS.
8-14 DAY OUTLOOK FOR JUL 28 - AUG 03, 2023
ENSEMBLE MEANS ARE IN GOOD AGREEMENT THAT THE MID-LEVEL RIDGING PEAKS IN
STRENGTH ACROSS THE EASTERN AND NORTH-CENTRAL CONUS AT THE BEGINNING OF WEEK-2,
WHILE A TROUGH AMPLIFIES OVER SOUTHEASTERN CANADA BY THE END OF JULY. ANOMALOUS
HEAT EARLY IN WEEK-2 RESULTS IN INCREASED ABOVE-NORMAL TEMPERATURE
PROBABILITIES ACROSS THE MIDWEST AND MOST OF THE NORTHEAST, ALTHOUGH
PROBABILITIES TAPER OFF FROM SOUTH TO NORTH GIVEN THE EXPECTATION FOR A
MODERATING TREND LATER DURING WEEK-2. ELSEWHERE, THROUGHOUT THE SOUTHEAST,
GREAT PLAINS, AND WEST, THE PERSISTENTLY STRONG RIDGE ALOFT FAVORS ABOVE-NORMAL
TEMPERATURES WITH THE LARGEST PROBABILITIES (ABOVE 70 PERCENT) FORECAST ACROSS
THE CENTRAL TO SOUTHERN GREAT PLAINS AND OZARKS REGION, PREDICTED TO BE LOCATED
ALONG THE AMPLIFIED RIDGE AXIS AND SUPPORTED BY THE TEMPERATURE TOOLS.
THE PRECIPITATION TOOLS CONTINUE TO OFFER WEAK OR CONFLICTING SIGNALS
THROUGHOUT THE FORECAST DOMAIN, WHICH IS TYPICAL FOR MID-SUMMER. THE WEEK-2
PRECIPITATION OUTLOOK WAS PRIMARILY BASED ON THE CONSOLIDATION TOOL
(SKILL-BASED GEFS AND ECMWF REFORECASTS) AND THE ANALOG TOOL DERIVED FROM THE
500-HPA HEIGHT BLEND. THE GEFS AND ECMWF REFORECAST TOOLS HAVE TRENDED WETTER
ACROSS THE SOUTHWEST AS THEIR ENSEMBLE MEANS CONTINUE TO DEPICT A FAVORABLE
500-HPA RIDGE AXIS OVER THE FOUR CORNERS REGION FOR ENHANCED MONSOONAL FLOW.
THE GFS MODEL REMAINS CONSISTENT WITH A TROPICAL CYCLONE FORMING OVER THE EAST
PACIFIC NEXT WEEK AND A TRACK NORTHWESTWARD TOWARDS THE BAJA PENINSULA. IF THIS
WERE TO OCCUR, THEN A SURGE OF LOW TO MID-LEVEL MOISTURE COULD SPREAD NORTHWARD
FROM THE GULF OF CALIFORNIA INTO THE DESERT SOUTHWEST. BASED ON THE REFORECAST
TOOLS, LONGWAVE PATTERN, AND AN INCREASED POTENTIAL FOR AN EAST PACIFIC TC
DURING WEEK-2, THE COVERAGE OF FAVORED ABOVE-NORMAL PRECIPITATION WAS EXPANDED
TO INCLUDE MORE OF THE SOUTHWEST, GREAT BASIN, AND CENTRAL ROCKIES. FARTHER TO
THE NORTH, BELOW-NORMAL PRECIPITATION IS MORE LIKELY FOR THE INTERIOR PACIFIC
NORTHWEST. AS 500-HPA HEIGHTS DECREASE ACROSS THE NORTHERN TIER OF THE CENTRAL
AND EASTERN CONUS LATER IN WEEK-2, THE OUTLOOK LEANS TOWARDS ABOVE-NORMAL
PRECIPITATION ACROSS MUCH OF THE NORTHERN GREAT PLAINS, MIDWEST, AND NORTHEAST.
HOWEVER, IT SHOULD BE NOTED THAT PROBABILITIES ARE TEMPERED DUE TO LOW
CONFIDENCE ON THE SPATIAL EXTENT OF CONVECTIVE RAINFALL. STRONG RIDGING ALOFT
CONTINUES TO FAVOR DRIER-NORMAL-CONDITIONS ACROSS THE SOUTHERN GREAT PLAINS,
LOWER MISSISSIPPI VALLEY, AND PARTS OF THE SOUTHEAST.
NEAR TO ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR ALASKA, CONSISTENT WITH A
500-HPA RIDGE OVER EASTERN MAINLAND ALASKA AND POSITIVE HEIGHT DEPARTURES. DUE
TO A WEAK TROUGH UPSTREAM OVER THE EASTERN BERING SEA, ABOVE-NORMAL
PRECIPITATION PROBABILITIES ARE SLIGHTLY ELEVATED FOR MOST OF MAINLAND ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z 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: AVERAGE, 3 OUT OF 5, DUE TO HIGH
CONFIDENCE IN THE TEMPERATURE OUTLOOK OFFSET BY LOWER CONFIDENCE IN THE
PRECIPITATION OUTLOOK.
FORECASTER: BRAD PUGH
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 17.
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:
19980731 - 19930731 - 19670713 - 19960723 - 19790714
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:
19930730 - 19980731 - 19790714 - 19670713 - 19960722
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 26 - 30 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B N OREGON N B NRN CALIF A B
SRN CALIF A N IDAHO A B NEVADA A B
W MONTANA A N E MONTANA A N WYOMING A N
UTAH A N ARIZONA A N COLORADO A N
NEW MEXICO A B N DAKOTA A A S DAKOTA A N
NEBRASKA A N KANSAS A B OKLAHOMA A B
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A A IOWA A N MISSOURI A B
ARKANSAS A B LOUISIANA A B WISCONSIN A A
ILLINOIS A N MISSISSIPPI A B MICHIGAN A A
INDIANA A N OHIO A N KENTUCKY A B
TENNESSEE A B ALABAMA A B NEW YORK A N
VERMONT A N NEW HAMP A N MAINE A N
MASS A N CONN A N RHODE IS A N
PENN A N NEW JERSEY A N W VIRGINIA A N
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A B S CAROLINA A B GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N A AK WESTERN A A AK INT BSN A A
AK S INT A A AK SO COAST A N AK PNHDL A B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 28 - AUG 03, 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A B OREGON A N NRN CALIF A N
SRN CALIF A A IDAHO A A NEVADA A A
W MONTANA A N E MONTANA A N 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 N KANSAS A B 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 A MISSISSIPPI A B MICHIGAN A A
INDIANA A A OHIO A A KENTUCKY A N
TENNESSEE A N ALABAMA A B NEW YORK A A
VERMONT N A NEW HAMP A A MAINE N A
MASS A A CONN A A RHODE IS A A
PENN A A NEW JERSEY A N W VIRGINIA A A
MARYLAND A N DELAWARE A N VIRGINIA A N
N CAROLINA A N S CAROLINA A N GEORGIA A B
FL PNHDL A B FL PENIN A N AK N SLOPE A A
AK ALEUTIAN N N AK WESTERN N A AK INT BSN A A
AK S INT A A AK SO COAST N N AK PNHDL A 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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