Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2
000
FXUS06 KWBC 241900
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT FRI OCTOBER 24 2014

6-10 DAY OUTLOOK FOR OCT 30 - NOV 03, 2014

THE VARIOUS ENSEMBLE MEANS AND DETERMINISTIC RUNS ARE IN FAIRLY POOR AGREEMENT
TODAY OVER THE PACIFIC-NORTH AMERICA DOMAIN DURING THE 6-10 DAY FORECAST
PERIOD. THE ECMWF AND GFS DETERMINISTIC SOLUTIONS DEPICT SIGNIFICANTLY
AMPLIFIED 500-HPA LONG WAVE FEATURES, WHILE THEIR RESPECTIVE ENSEMBLE MEANS ARE
QUASI-ZONAL. THE ECMWF ENSEMBLE MEAN PREDICTS A TROUGH-RIDGE-TROUGH PATTERN
ACROSS NORTH AMERICA, WITH A TROUGH ALSO OVER THE BERING SEA. THE 0Z RUNS OF
BOTH THE GFS ENSEMBLE MEAN AND CANADIAN ENSEMBLE MEAN FAVOR A BROAD TROUGH
CENTERED NEAR THE WEST COAST, AND SLIGHT RIDGING OVER MOST OF THE NATION EAST
OF THE ROCKIES. THE MORE RECENT 6Z INTEGRATION OF THE GEFS FORECASTS A FLATTER
VERSION OF THE 0Z ECMWF ENSEMBLE MEAN.

LARGE DIFFERENCES IN PREDICTED CIRCULATION PATTERNS ARE FAIRLY COMMON IN
AUTUMN, AS THE WESTERLIES STRENGTHEN AND SHIFT SOUTH, AND AS WESTERN PACIFIC
TYPHOONS GET CAUGHT UP INTO THE MID-LATITUDE CIRCULATION WELL UPSTREAM OF THE
U.S. IT IS VERY DIFFICULT TO PREDICT THE TIMING AND AMPLITUDE OF INDIVIDUAL
SHORT WAVES EMBEDDED WITHIN THE MEAN FLOW. CONSIDERING THIS, AND TODAY`S MODEL
RUNS, A 500-HPA HEIGHT BLEND WAS CONSTRUCTED WITH SLIGHTLY GREATER WEIGHTS
ASSIGNED TO THE 0Z ECMWF ENSEMBLE MEAN AND THE 6Z GFS ENSEMBLE MEAN, WHICH HAVE
THE EDGE IN PERFORMANCE COMPARED TO THE OTHER MODEL SOLUTIONS DURING THE PAST
TWO MONTHS. IN THIS PERIOD OF GREATER UNCERTAINTY, IT WAS ALSO DEEMED PRUDENT
TO PREDICT A LOW-AMPLITUDE CIRCULATION PATTERN, MAINTAINING CONTINUITY FROM
YESTERDAY`S FORECAST.

THE LOW-AMPLITUDE FLOW ALOFT OVER THE CONUS LEADS TO ELEVATED CHANCES FOR
ABOVE-NORMAL TEMPERATURES FOR MUCH OF THE NATION. NEAR-NORMAL TEMPERATURES ARE
FAVORED OVER PARTS OF NORTHERN CALIFORNIA, THE EASTERN GREAT LAKES REGION, AND
THE NORTHERN AND MIDDLE ATLANTIC COAST STATES, DUE TO EXPECTED 500-HPA TROUGHS
IN THOSE AREAS. IN ALASKA, NEAR TO BELOW-NORMAL TEMPERATURES ARE FAVORED SOUTH
OF THE BROOKS RANGE, BASED ON THE EXPECTATION OF BELOW-NORMAL 500-HPA HEIGHTS
AND AN ENHANCED JET ACROSS THE ALEUTIANS. ODDS FOR ABOVE-NORMAL TEMPERATURES
ARE SLIGHTLY ENHANCED NORTH OF THE BROOKS RANGE, IN PART BASED ON THE NAEFS,
REFORECAST, AND 0Z ECMWF ENSEMBLE MEAN CALIBRATED 2-METER TEMPERATURES. THE
ADJOINING PORTIONS OF THE SOUTHERN BEAUFORT SEA ARE CURRENTLY EITHER STILL
ICE-FREE, OR IN THE PROCESS OF FREEZING AT THIS TIME, MEANING THIS RELATIVE
HEAT SOURCE IS GRADUALLY BEING CUT OFF.

ABOVE-MEDIAN PRECIPITATION IS FAVORED OVER MOST OF MAINLAND ALASKA AND THE
ALEUTIANS, MUCH OF THE WEST (AS FAR SOUTH AS SOUTHERN CALIFORNIA), MOST OF THE
GREAT LAKES AND MIDWEST, AND SOUTHERN FLORIDA. THIS IS GENERALLY DUE TO THE
EXPECTATION OF UPPER-LEVEL TROUGHS AND MEAN STORM TRACKS IN THESE AREAS. IN
SOUTHERN FLORIDA, THE BASIS FOR THE ABOVE-MEDIAN RAINFALL IS THE ANTICIPATION
OF A COLD FRONT MOVING THROUGH THE REGION EARLY IN THE PERIOD. ODDS FOR
BELOW-MEDIAN PRECIPITATION ARE ELEVATED ACROSS THE ALASKA PANHANDLE, MUCH OF
THE SOUTHWEST, GREAT PLAINS, AND MUCH OF BOTH THE GULF COAST AND ATLANTIC COAST
STATES. THIS IS GENERALLY SUPPORTED BY WEAK RIDGING AND ASSOCIATED POSITIVE
HEIGHT ANOMALIES, AND AREAS WHICH ARE ANTICIPATED TO BE NEAR OR BEHIND MEAN
TROUGH AXES.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 20% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 25% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY`S OPERATIONAL 6Z GFS CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN
ENSEMBLE MEAN CENTERED ON DAY 8, AND 20% OF TODAY`S 0Z CANADIAN ENSEMBLE MEAN
CENTERED ON DAY 8


MODEL OF THE DAY: TODAY`S 0Z EUROPEAN ENSEMBLE MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO
FAIRLY POOR AGREEMENT IN THE DETAILS BETWEEN THE VARIOUS ENSEMBLE MEANS AND
DETERMINISTIC SOLUTIONS.

8-14 DAY OUTLOOK FOR NOV 01 - 07 2014

THE 500-HPA HEIGHT FORECAST FOR THE WEEK-2 PERIOD ACROSS THE PACIFIC-NORTH
AMERICA DOMAIN IS SIGNIFICANTLY BETTER DEFINED TODAY COMPARED TO YESTERDAY.
THERE HAS BEEN A GENERAL CONVERGENCE OF SOLUTIONS TOWARD WHAT THE 0Z ECMWF
ENSEMBLE MEAN WAS PREDICTING YESTERDAY, NAMELY, A TROUGH IN THE FAR WEST, AND
RIDGING OVER THE EAST-CENTRAL CONUS. THIS IS LESS OBVIOUS WITH THE FLATTER
ENSEMBLE MEAN PATTERNS THAN IT IS WITH THE HIGHER AMPLITUDE DETERMINISTIC GFS
SOLUTIONS. YESTERDAY`S 0Z, 6Z, AND 12Z DETERMINISTIC GFS RUNS WERE COMPLETELY
OPPOSITE TO WHAT THEY ARE TODAY OVER THE CONUS, THAT IS, A WESTERN RIDGE AND
EASTERN TROUGH. THIS PREDICTED REVERSAL OF LONG-WAVES WITH THE GFS MODEL IS
THOUGHT TO BE DUE, AT LEAST IN PART, TO THE RECENT SATELLITE DATA INGEST
PROBLEM, WHICH NOW APPEARS TO BE RESOLVED.

THE WEEK-2 TEMPERATURE AND PRECIPITATION PATTERNS ARE SIMILAR TO THOSE FOR THE
6-10 DAY PERIOD, WITH A FEW MINOR EXCEPTIONS. THE ALASKA PANHANDLE IS FORECAST
TO EXPERIENCE A WETTER PATTERN WITH A MEAN TROUGH AXIS JUST TO ITS WEST, AND
BELOW-MEDIAN PRECIPITATION IS FAVORED FOR THE SOUTHERN HALF OF CALIFORNIA. FROM
MISSOURI SOUTHWESTWARD THROUGH EASTERN TEXAS, CONDITIONS ARE PREDICTED TO TREND
FROM BELOW-MEDIAN PRECIPITATION TO NEAR AND ABOVE-MEDIAN PRECIPITATION.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 15% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 15% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY
11, 5% OF TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 11, 10% OF TODAY`S
OPERATIONAL 6Z GFS CENTERED ON DAY 11, 30% 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 IS: NEAR AVERAGE, 3 OUT OF 5, DUE
TO MUCH-IMPROVED MODEL AGREEMENT COMPARED TO YESTERDAY.


FORECASTER: ANTHONY ARTUSA

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
NOVEMBER 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:
20051028 - 19531105 - 19821025 - 19621007 - 19841010


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:
20051028 - 19621003 - 19531105 - 19791023 - 19621008


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR OCT 30 - NOV 03, 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 01 - 07 2014

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

$$




USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.