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FXUS06 KWBC 071921
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI JULY 07 2023
6-10 DAY OUTLOOK FOR JUL 13 - 17 2023
TODAY'S MODEL SOLUTIONS ARE IN GOOD AGREEMENT REGARDING AN AMPLIFIED 500-HPA
CIRCULATION PATTERN ACROSS THE MID- TO HIGH-LATITUDES OF NORTH AMERICA DURING
THE 6-10 DAY PERIOD. ANOMALOUS MID-LEVEL RIDGES ARE FORECAST ACROSS THE
ALEUTIANS, NORTHWESTERN CANADA, AND THE NORTHWEST ATLANTIC, WITH AN ANOMALOUS
MID-LEVEL TROUGH PREDICTED OVER EAST-CENTRAL NORTH AMERICA. THIS TRANSLATES
INTO ABOVE-NORMAL 500-HPA HEIGHTS ACROSS MUCH OF ALASKA AND WESTERN CANADA, AND
OVER PARTS OF THE NORTHEAST CONUS. THE TROUGHING OVER THE EAST-CENTRAL CONUS
FAVORS NEAR- TO BELOW-NORMAL HEIGHTS FROM THE NORTHERN PLAINS
EAST-SOUTHEASTWARD ACROSS MUCH OF THE MISSISSIPPI AND OHIO VALLEYS, GREAT
LAKES, APPALACHIANS, AND MID-ATLANTIC REGION. SUBTROPICAL RIDGING AT 500-HPA IS
PREDICTED ACROSS THE SOUTHERN AND WESTERN CONUS, WITH HEIGHTS CULMINATING NEAR
597-DM OVER THE DESERT SOUTHWEST.
REFORECAST CALIBRATED TEMPERATURE PROBABILITIES FROM THE VARIOUS ENSEMBLE MEANS
AGREE ON INCREASED CHANCES OF BELOW-NORMAL TEMPERATURES OVER MUCH OF THE
NORTHERN AND CENTRAL GREAT PLAINS, THE UPPER AND MIDDLE MISSISSIPPI VALLEY,
GREAT LAKES, AND OHIO VALLEY. THE 0Z CANADIAN ENSEMBLE MEAN IS BY FAR THE
COOLEST SOLUTION, DEPICTING ENHANCED ODDS OF BELOW-NORMAL TEMPERATURES OVER
MOST OF THE CENTRAL AND EASTERN CONUS, WHICH SEEMS TO BE OVERDONE.
BIAS-CORRECTED TEMPERATURES FROM THE 0Z ECMWF, GFS, AND CANADIAN ENSEMBLE MEANS
PREDICT MORE WIDESPREAD COVERAGE OF FAVORED BELOW-NORMAL TEMPERATURES COMPARED
TO THE REFORECAST TEMPERATURE COUNTERPARTS. FOR MOST OF THE REMAINDER OF THE
CONUS, WHICH INCLUDES A LARGE FRACTION OF THE LOWER 48 STATES, ABOVE-NORMAL
MEAN TEMPERATURES ARE FAVORED DURING THE 6-10 DAY PERIOD. OVER THE NORTHEAST
AND MID-ATLANTIC STATES, THE ELEVATED ODDS OF ABOVE-NORMAL TEMPERATURE CHANCES
ARE RELATED TO AN UPSTREAM MID-LEVEL TROUGH, AND INCREASED SOUTHERLY FLOW. FOR
THE SOUTHERN AND WESTERN CONUS, THE ANTICIPATED RELATIVE WARMTH IS DUE TO THE
PROXIMITY OF THE SUBTROPICAL RIDGE, WITH THE GREATEST PROBABILITIES FAVORING
ABOVE-NORMAL TEMPERATURES INDICATED OVER PORTIONS OF THE SOUTHWESTERN AND
SOUTH-CENTRAL CONUS, AND FLORIDA. NEAR THE COAST OF SOUTHERN CALIFORNIA,
SEA-SURFACE TEMPERATURES ARE NEAR- TO BELOW-NORMAL AND ARE EXPECTED TO MODERATE
MAXIMUM TEMPERATURES A BIT. MID-LEVEL RIDGING AND ASSOCIATED ABOVE-NORMAL
MID-LEVEL HEIGHTS FAVOR ABOVE-NORMAL TEMPERATURES FOR MOST OF ALASKA.
TROUGHING OVER THE EAST-CENTRAL CONUS IS LIKELY TO RESULT IN A SERIES OF
FRONTAL SYSTEMS MOVING ACROSS THE FAR NORTHERN PORTIONS OF THE INTERMOUNTAIN
WEST AND ROCKIES, AND CONTINUING EASTWARD AND SOUTHWARD ACROSS MUCH OF THE
NATION EAST OF THE ROCKIES DURING DAYS 6-10 AND WEEK-2. THERE ARE ELEVATED
PROBABILITIES OF ABOVE-NORMAL PRECIPITATION ACROSS THESE SAME GENERAL AREAS,
WITH THE HIGHER PROBABILITIES OF ABOVE-NORMAL PRECIPITATION BEING FAVORED FROM
NORTH-CENTRAL PORTIONS OF THE PLAINS AND MIDDLE MISSISSIPPI VALLEY EASTWARD AND
NORTHEASTWARD OVER THE OHIO AND TENNESSEE VALLEYS, MUCH OF THE APPALACHIANS,
THE MID-ATLANTIC REGION AND NORTHEAST. BELOW-NORMAL PRECIPITATION PROBABILITIES
ARE ENHANCED OVER MOST AREAS WEST OF THE CONTINENTAL DIVIDE AND PORTIONS OF
TEXAS AND LOUISIANA. THIS IS ATTRIBUTED TO THE PROXIMITY OF THE SUBTROPICAL
RIDGE AND A DELAYED ONSET OF THE SOUTHWEST MONSOON. SOME OF THE TOOLS HINT AT
MODEST AMOUNTS OF PRECIPITATION NEAR THE MEXICAN BORDER WITH ARIZONA AND NEW
MEXICO, AND THIS MAY BE DUE TO AN INFLUX OF SUBTROPICAL MOISTURE DUE TO
TROPICAL CYCLONES PASSING WELL TO THE SOUTH OVER THE EASTERN PACIFIC. WITH THE
SUBTROPICAL RIDGE APPROACHING ITS CLIMATOLOGICAL POSITION OVER THE FOUR CORNERS
REGION, SOME OF THIS MOISTURE COULD ALSO BE RELATED TO THUNDERSTORM CLUSTERS
COMING OFF THE WESTERN SLOPES OF THE SIERRA MADRE OCCIDENTAL RANGE IN MEXICO
GETTING TRANSLATED NORTHWARD INTO THE AMERICAN SOUTHWEST BY GULF OF CALIFORNIA
SURGES. EVEN SO, PRECIPITATION AMOUNTS ARE FORECAST TO BE MINIMAL OVER THE
SOUTHWEST DURING WEEK-2. IN ALASKA, THERE ARE MODEST TILTS TOWARDS ABOVE-NORMAL
PRECIPITATION ACROSS NORTHERN AND CENTRAL SECTIONS OF THE STATE, ATTRIBUTED TO
INCREASED ONSHORE FLOW NORTH OF THE ALEUTIAN RIDGE. BELOW-NORMAL PRECIPITATION
IS FAVORED OVER SOUTHWEST PARTS OF ALASKA, INCLUDING THE ALASKA PENINSULA AND
KODIAK ISLAND, EAST OF THE ALEUTIAN RIDGE AXIS.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
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
PERSISTENT SYNOPTIC PATTERN AND GOOD AGREEMENT AMONG FORECAST MODELS, OFFSET BY
RELATIVELY MINOR DIFFERENCES IN THE TEMPERATURE AND PRECIPITATION GUIDANCE.
8-14 DAY OUTLOOK FOR JUL 15 - 21 2023
THE 500-HPA HEIGHT PATTERN DURING WEEK-2 IS PREDICTED TO BE SIMILAR TO THE 6-10
DAY PERIOD, WITH A GENERAL DECREASE IN AMPLIFICATION PREDICTED OVER THE
FORECAST DOMAIN. THE MID-LEVEL RIDGE NEAR THE ALEUTIANS IS FORECAST TO SHIFT
SOUTHWARD, WHILE THE POSITIVE HEIGHT ANOMALY CENTERS OVER WESTERN CANADA AND
THE NORTHWEST ATLANTIC WEAKEN IN PLACE. THE MID-LEVEL TROUGH OVER THE GREAT
LAKES AND OHIO VALLEY IS ALSO FORECAST TO WEAKEN DURING WEEK-2, WITH VERY
MODEST EASTWARD PROPAGATION. SUBTROPICAL RIDGING AND ASSOCIATED ABOVE-NORMAL
500-HPA HEIGHTS ARE FORECAST TO CONTINUE ACROSS MUCH OF THE SOUTHERN AND
WESTERN CONUS. MID-LEVEL HEIGHT DEPARTURES OVER THE SOUTH-CENTRAL AND
SOUTHWESTERN CONUS ARE PREDICTED BY THE VARIOUS ENSEMBLE MEANS TO RANGE FROM
+30 TO +50 METERS (SIGNIFICANT AT THIS TIME OF YEAR), WITH THE MAXIMUM HEIGHT
DEPARTURE DEPICTED OFF THE CALIFORNIA COAST.
THE EXPECTED WEAKENING OF THE MID-LEVEL TROUGH OVER THE EAST-CENTRAL CONUS
LEADS TO A DECREASE IN COVERAGE OF FAVORED BELOW-NORMAL TEMPERATURES, RELATIVE
TO THE 6-10 DAY PERIOD. PROBABILITIES OF ABOVE-NORMAL TEMPERATURES REMAIN
ELEVATED OVER MOST OF THE REMAINDER OF THE CONUS, SUPPORTED BY REFORECAST
TEMPERATURES FROM THE 0Z GFS AND ECMWF ENSEMBLE MEANS, AND TO A LESSER EXTENT
BIAS-CORRECTED TEMPERATURES. WIDESPREAD COVERAGE OF FAVORED ABOVE-NORMAL
TEMPERATURE CHANCES IS CONSISTENT WITH THE MANUAL 500-HPA HEIGHT ANOMALY
FORECAST, WHICH PREDICTS NEAR- TO ABOVE-NORMAL MID-LEVEL HEIGHTS OVER
PRACTICALLY THE ENTIRE CONUS. THE SUBTROPICAL RIDGE PREDICTED OVER THE SOUTHERN
AND WESTERN PORTIONS OF THE LOWER 48 STATES IS EXPECTED TO SHIFT WESTWARD
DURING WEEK-2, WITH THE LARGEST POSITIVE HEIGHT ANOMALIES (> +30 METERS)
LOCATED OVER THE SOUTHWESTERN QUADRANT OF THE CONUS. INCREASED CHANCES OF
ABOVE-NORMAL TEMPERATURES COMBINED WITH THE APPROACH OF CLIMATOLOGICAL PEAK
HEATING COULD LEAD TO WIDESPREAD EXCESSIVE HEAT CONCERNS FOR THIS PART OF THE
NATION, INCLUDING INTERIOR PORTIONS OF CALIFORNIA. NEAR THE SOUTHERN COAST OF
CALIFORNIA, SEA-SURFACE TEMPERATURES ARE NEAR- TO BELOW-NORMAL AND ARE EXPECTED
TO MODERATE MAXIMUM TEMPERATURES SLIGHTLY. INCREASED CLOUD COVER AND MODESTLY
ENHANCED CHANCES OF ABOVE-NORMAL PRECIPITATION IN ADVANCE OF AN APPROACHING
MID-LEVEL TROUGH ARE EXPECTED TO RESULT IN TEMPERATURES CLOSE TO NORMAL ACROSS
MUCH OF THE PACIFIC NORTHWEST. ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR
INTERIOR PORTIONS OF ALASKA, WITH A SMALL AREA OF BELOW-NORMAL TEMPERATURES
FAVORED FOR PARTS OF THE IMMEDIATE WEST COAST.
AS DISCUSSED IN THE 6-10 DAY OUTLOOK, TROUGHING IS FORECAST TO LEAD TO ONE OR
MORE FRONTAL SYSTEMS MOVING ACROSS THE EASTERN CONUS INTO THE WEEK-2 PERIOD AS
WELL. AS A RESULT, ABOVE-NORMAL PRECIPITATION PROBABILITIES ARE INCREASED OVER
MUCH OF THE EASTERN CONUS, WITH PROBABILITIES IN EXCESS OF 40 PERCENT FROM
TENNESSEE AND KENTUCKY NORTHEASTWARD ACROSS THE MID-ATLANTIC AND NORTHEAST.
PROBABILITIES MODESTLY FAVORING ABOVE-NORMAL PRECIPITATION ARE ALSO INDICATED
OVER THE VICINITY OF WASHINGTON STATE. ODDS FAVORING BELOW-NORMAL PRECIPITATION
ARE DEPICTED FOR MUCH OF THE WEST, SOUTHERN PLAINS, AND INTO LOUISIANA. AS WITH
THE EARLIER 6-10 DAY OUTLOOK, THIS IS DUE TO PREDICTED SUBTROPICAL RIDGING OVER
THE REGION, AND A DELAYED ONSET TO THE SOUTHWEST MONSOON. HOWEVER, THERE ARE
SIGNS OF INCREASING MOISTURE OVER PARTS OF THE DESERT SOUTHWEST TIED TO
POTENTIAL EAST PACIFIC TROPICAL CYCLONE ACTIVITY, WHICH MAY SIGNAL THE START OF
THE MONSOON. FOR THE TIME BEING, HOWEVER, THE MAIN WEATHER CONCERN FOR THE
SOUTHWEST IS THE EXTENDED PERIOD OF EXCESSIVE HEAT. ABOVE-NORMAL PRECIPITATION
CHANCES ARE INCREASED OVER CENTRAL AND SOUTHERN ALASKA, AS THE ALEUTIAN RIDGE
WEAKENS AND ASSOCIATED ONSHORE FLOW (ON ITS NORTHERN PERIPHERY) SHIFTS
SOUTHWARD.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 35% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 40% OF TODAY'S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11, AND 25% 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 AGREEMENT AMONG MODEL ENSEMBLES ON THE PERSISTENT SYNOPTIC PATTERN, OFFSET
BY DECREASING AMPLIFICATION AND AN EXPECTED WESTWARD SHIFT OF THE SUBTROPICAL
RIDGE.
FORECASTER: ANTHONY A
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 20.
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:
19520711 - 19780708 - 19890622 - 19780719 - 19580708
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:
19520711 - 19780708 - 19580708 - 19720717 - 19510618
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 13 - 17 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON A N OREGON A B NRN CALIF A N
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A N E MONTANA B A WYOMING N B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA B A S DAKOTA B A
NEBRASKA B A KANSAS N A OKLAHOMA A A
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA B N IOWA B A MISSOURI N A
ARKANSAS A A LOUISIANA A B WISCONSIN B N
ILLINOIS B A MISSISSIPPI A A MICHIGAN B A
INDIANA B A OHIO B A KENTUCKY N A
TENNESSEE N A ALABAMA A A 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 N A NEW JERSEY A A W VIRGINIA N A
MARYLAND A A DELAWARE A A VIRGINIA A A
N CAROLINA A A S CAROLINA A A GEORGIA A A
FL PNHDL A N FL PENIN A N AK N SLOPE N A
AK ALEUTIAN N N AK WESTERN A A AK INT BSN A A
AK S INT A N AK SO COAST A N AK PNHDL A N
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JUL 15 - 21 2023
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON N N OREGON A N NRN CALIF A N
SRN CALIF A B IDAHO A B NEVADA A B
W MONTANA A N E MONTANA A N WYOMING A B
UTAH A B ARIZONA A B COLORADO A B
NEW MEXICO A B N DAKOTA A N S DAKOTA N N
NEBRASKA N N KANSAS A A OKLAHOMA A N
N TEXAS A B S TEXAS A B W TEXAS A B
MINNESOTA A N IOWA N N MISSOURI A A
ARKANSAS A A LOUISIANA A N WISCONSIN A N
ILLINOIS N A MISSISSIPPI A N MICHIGAN N A
INDIANA N A OHIO N A KENTUCKY N A
TENNESSEE A A ALABAMA A A NEW YORK N 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 N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA A A
N CAROLINA A N S CAROLINA A A GEORGIA A A
FL PNHDL A N FL PENIN A N AK N SLOPE N N
AK ALEUTIAN N N AK WESTERN N A AK INT BSN N A
AK S INT N A AK SO COAST N 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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