Prognostic Meteorological Discussion
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FXUS06 KWBC 281901
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 28 2017

6-10 DAY OUTLOOK FOR AUG 03 - 07 2017

TODAY`S DYNAMICAL MODELS ARE IN FAIRLY GOOD AGREEMENT ON THE PREDICTED
MID-TROPOSPHERIC CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN. THE OFFICIAL
BLENDED 500-HPA HEIGHT FIELD DEPICTS MEAN TROUGHS OVER THE GULF OF ALASKA/EAST
PACIFIC AND EAST-CENTRAL NORTH AMERICA, AND MEAN RIDGES OVER THE WEST-CENTRAL
CONUS, EASTERN ALASKA, AND THE WESTERN ALEUTIANS. THERE ARE RELATIVELY MINOR
DIFFERENCES BETWEEN THE DYNAMICAL MODELS IN PREDICTED AMPLITUDE AND PHASE OF
THESE KEY LONG-WAVE FEATURES. ONE OF THE MORE UNCERTAIN ASPECTS OF THIS
FORECAST INVOLVES THE LONG-WAVE TROUGH ANTICIPATED OVER THE EAST-CENTRAL LOWER
48 STATES. INSPECTION OF MODEL GUIDANCE INDICATES SEVERAL SHORTWAVES EMBEDDED
WITHIN THE LONG-WAVE TROUGH ARE LIKELY TO MOVE ACROSS THE GREAT LAKES REGION
AND NORTHEAST, RESULTING IN VARIABLE TEMPERATURE AND PRECIPITATION PATTERNS
DURING THE 6-10 DAY PERIOD. ANOTHER AREA OF UNCERTAINTY INVOLVES THE IMPORTANT
UPSTREAM REGION THAT ENCOMPASSES THE BERING SEA, ALEUTIANS, AND GULF OF ALASKA.
SOME RECENT MODEL RUNS, SUCH AS THE 0Z AND 6Z GFS ENSEMBLE MEANS, AND THE 0Z
AND 6Z DETERMINISTIC GFS RUNS, PREDICT THE DEVELOPMENT OF A 500-HPA TROUGH NEAR
THE KAMCHATKA PENINSULA/WESTERN BERING SEA REGION, WHICH COULD HELP AMPLIFY THE
DOWNSTREAM RIDGE OVER THE ALEUTIANS, AND DEEPEN THE TROUGH EXPECTED OVER THE
GULF OF ALASKA/EAST PACIFIC AREA. AT THE 5820 METER LEVEL, THE VARIOUS
SPAGHETTI MAPS SHOW LOW TO MODERATE SPREAD AMONG THE INDIVIDUAL ENSEMBLE
MEMBERS OVER THE CONUS, WITH THE GREATER UNCERTAINTY REGARDING THE PREDICTED
DEPTH OF THE EAST-CENTRAL CONUS TROUGH. AT HIGHER LATITUDES (5640 METER LEVEL),
THE SPAGHETTI MAPS REVEAL HIGH SPREAD AND MUCH UNCERTAINTY ACROSS THE BERING
SEA, ALASKA, AND GULF OF ALASKA REGION.

ODDS OF ABOVE NORMAL TEMPERATURES ARE ELEVATED ACROSS MOST OF ALASKA, MOST
AREAS WEST OF THE CONTINENTAL DIVIDE, THE NORTHERN GREAT PLAINS AND WESTERN
NEBRASKA, NORTHWEST MINNESOTA, THE NORTHEAST, THE FLORIDA PENINSULA, AND
SOUTHERN PORTIONS OF TEXAS. THIS IS GENERALLY DUE TO THE PREDICTED PRESENCE OF
500-HPA RIDGES AND ASSOCIATED ABOVE NORMAL HEIGHTS. THE FAVORED AREA OF ABOVE
NORMAL TEMPERATURES ACROSS THE NORTHEAST IS RELATED TO A PREDICTED APPROACHING
500-HPA TROUGH. BELOW NORMAL TEMPERATURES ARE FAVORED FOR MUCH OF THE CENTRAL
AND SOUTHERN GREAT PLAINS, THE MIDDLE AND LOWER MISSISSIPPI VALLEY, THE LOWER
OHIO AND TENNESSEE VALLEYS, THE SOUTHERN APPALACHIANS, AND MOST OF THE
SOUTHEAST (EXCLUDING FLORIDA). THIS IS DUE TO THE PREDICTED PRESENCE OF A
NEARBY 500-HPA TROUGH AND LIKELIHOOD FOR ENHANCED RAINFALL, AND IS CONSISTENT
WITH VARIOUS DYNAMICAL MODEL TEMPERATURE FORECASTS, AND THE CPC CONSOLIDATION
TEMPERATURE FORECAST.

ABOVE NORMAL PRECIPITATION IS FAVORED IN PORTIONS OF ALASKA, CENTRAL AND
SOUTHERN PORTIONS OF THE INTERMOUNTAIN REGION, THE EXTREME SOUTHERN ROCKIES,
THE SOUTHERN PLAINS, THE LOWER MISSISSIPPI VALLEY, GULF COAST STATES, AND MOST
OF THE SOUTHERN ATLANTIC REGION, AS WELL AS THE EASTERN GREAT LAKES REGION, AND
NORTHERN AND CENTRAL APPALACHIANS. THIS IS ATTRIBUTED TO THE EXPECTATION OF
APPROACHING 500-HPA TROUGHS AND ASSOCIATED WIDESPREAD ASCENT OF AIR, AND IN THE
SOUTHWESTERN CONUS, A COMBINATION OF A BACKDOOR COLD FRONT AND THE SOUTHWEST
SUMMER MONSOON. BELOW NORMAL PRECIPITATION IS FAVORED OVER THE NORTHERN
INTERMOUNTAIN REGION, THE NORTHERN ROCKIES, NORTHERN AND CENTRAL PLAINS, AND
THE UPPER AND MIDDLE MISSISSIPPI VALLEY. THIS FAVORED AREA OF BELOW NORMAL
PRECIPITATION IS ASSOCIATED WITH AN ANTICIPATED 500-HPA RIDGE AND THE
SUBSIDENCE AREA ASSOCIATED WITH THE EASTERN CONUS TROUGH.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 15% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 10%
OF TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 10% OF TODAY`S OPERATIONAL 6Z
GFS CENTERED ON DAY 8, 25% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY
8, 10% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 15% 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
FAIRLY GOOD MODEL AGREEMENT, AND REASONABLE AGREEMENT AMONG THE VARIOUS
TEMPERATURE AND PRECIPITATION TOOLS, OFFSET BY THE POTENTIAL DEEPENING OF A
MEAN TROUGH OVER THE BERING SEA.

8-14 DAY OUTLOOK FOR AUG 05 - 11 2017

TODAY`S MODELS ARE IN FAIR AGREEMENT ON THE PREDICTED WEEK-2 500-HPA
CIRCULATION PATTERN ACROSS THE FORECAST DOMAIN. THE OVERALL CIRCULATION PATTERN
THAT IS EXPECTED FOR WEEK-2 IS SIMILAR TO THAT PREDICTED FOR DAYS 6-10, THOUGH
WITH A SLIGHTLY DEEPER TROUGH ANTICIPATED OVER NORTHWEST ALASKA. THERE ARE VERY
LARGE DIFFERENCES BETWEEN THE 0Z AND 6Z DETERMINISTIC GFS RUNS TODAY. THE 0Z
GFS DEPICTS A MUCH FLATTER FLOW PATTERN ACROSS THE PACIFIC-NORTH AMERICA DOMAIN
THAN DOES THE 6Z RUN, EXCEPT FOR A DEEP TROUGH OVER THE GULF OF ALASKA/EAST
PACIFIC AREA. THE 6Z RUN PREDICTS A MUCH MORE AMPLIFIED LONG-WAVE PATTERN OVER
THE FORECAST DOMAIN. VERY LITTLE WEIGHTING WAS ASSIGNED TO THE DETERMINISTIC
GFS RUNS TODAY IN THE MANUAL BLENDED HEIGHT FORECAST. ENSEMBLE SPREAD IS
MODERATE OVER MUCH OF THE FORECAST DOMAIN, BUT HIGH ACROSS THE BERING SEA,
ALASKA, AND THE GULF OF ALASKA REGION.

THE PREDICTED WEEK-2 TEMPERATURE PATTERN IS SIMILAR TO THAT ANTICIPATED DURING
THE 6-10 DAY PERIOD, THOUGH WITH SEVERAL ADJUSTMENTS. ONE ADJUSTMENT MADE TO
THE 6-10 DAY TEMPERATURE OUTLOOK IS THE EXPANSION OF FAVORED ABOVE NORMAL
TEMPERATURES ACROSS THE GREAT LAKES REGION. THIS IS DUE TO AN ANTICIPATED
WARMING TREND IN THIS AREA. THE PRIMARY MODIFICATION MADE WITH THE
PRECIPITATION OUTLOOK IS THE EXPANSION OF FAVORED ABOVE NORMAL PRECIPITATION
ACROSS MOST OF THE EASTERN CONUS, WITH SLIGHTLY ELEVATED PROBABILITIES. THIS IS
BASED ON ANTICIPATED GULF MOISTURE INFLOW ACROSS THIS REGION, AND THE
EXPECTATION OF SEVERAL COLD FRONT PASSAGES.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 20% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 10% OF TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 11, 5% OF TODAY`S
OPERATIONAL 6Z GFS CENTERED ON DAY 11, 25% 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 IS: BELOW AVERAGE, 2 OUT OF 5, DUE
TO FAIR MODEL AGREEMENT, OFFSET BY THE PREDICTION OF VERY MODEST 500-HPA HEIGHT
ANOMALIES.

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 1981-2010 BASE PERIOD MEANS FOR
TEMPERATURE...PRECIPITATION...AND 500-HPA HEIGHTS 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:
19930730 - 19560808 - 19670714 - 19590724 - 20000811


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:
20010806 - 19600710 - 19930729 - 20030711 - 19960808


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 03 - 07 2017

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    N     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    B     NEVADA      A    N
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    B
UTAH        A    N     ARIZONA     A    A     COLORADO    N    B
NEW MEXICO  B    N     N DAKOTA    A    B     S DAKOTA    A    B
NEBRASKA    N    B     KANSAS      B    B     OKLAHOMA    B    N
N TEXAS     B    A     S TEXAS     B    A     W TEXAS     B    A
MINNESOTA   N    B     IOWA        N    B     MISSOURI    B    B
ARKANSAS    B    N     LOUISIANA   B    A     WISCONSIN   N    B
ILLINOIS    B    B     MISSISSIPPI B    A     MICHIGAN    N    N
INDIANA     B    N     OHIO        N    A     KENTUCKY    B    N
TENNESSEE   B    N     ALABAMA     B    A     NEW YORK    A    A
VERMONT     A    A     NEW HAMP    A    N     MAINE       A    A
MASS        A    N     CONN        A    N     RHODE IS    A    N
PENN        N    A     NEW JERSEY  A    N     W VIRGINIA  N    N
MARYLAND    N    N     DELAWARE    A    N     VIRGINIA    N    N
N CAROLINA  N    N     S CAROLINA  B    N     GEORGIA     B    A
FL PNHDL    N    A     FL PENIN    A    A     AK N SLOPE  A    A
AK ALEUTIAN A    N     AK WESTERN  A    N     AK INT BSN  A    N
AK S INT    A    N     AK SO COAST N    A     AK PNHDL    N    A



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR AUG 05 - 11 2017

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  A    B     OREGON      A    N     NRN CALIF   A    N
SRN CALIF   A    N     IDAHO       A    N     NEVADA      A    N
W MONTANA   A    B     E MONTANA   A    B     WYOMING     A    N
UTAH        A    N     ARIZONA     A    A     COLORADO    B    N
NEW MEXICO  B    N     N DAKOTA    A    B     S DAKOTA    A    B
NEBRASKA    N    B     KANSAS      B    N     OKLAHOMA    B    N
N TEXAS     B    A     S TEXAS     N    A     W TEXAS     B    N
MINNESOTA   A    B     IOWA        N    N     MISSOURI    B    N
ARKANSAS    B    A     LOUISIANA   B    A     WISCONSIN   A    N
ILLINOIS    N    N     MISSISSIPPI B    A     MICHIGAN    A    N
INDIANA     N    A     OHIO        N    A     KENTUCKY    N    A
TENNESSEE   B    A     ALABAMA     B    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        A    A     NEW JERSEY  A    A     W VIRGINIA  N    A
MARYLAND    A    A     DELAWARE    A    A     VIRGINIA    A    A
N CAROLINA  A    A     S CAROLINA  N    A     GEORGIA     N    A
FL PNHDL    N    A     FL PENIN    A    N     AK N SLOPE  A    A
AK ALEUTIAN A    N     AK WESTERN  A    N     AK INT BSN  A    N
AK S INT    A    A     AK SO COAST N    A     AK PNHDL    N    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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