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FXUS06 KWBC 192001
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST FRI DECEMBER 19 2014

6-10 DAY OUTLOOK FOR DEC 25 - 29 2014

TODAY`S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON THE 500-HPA HEIGHT PATTERN
FORECAST FOR THE 6-10 DAY PERIOD. ALL MODELS ARE FORECASTING A RIDGE OVER THE
GULF OF ALASKA, AND A DOWNSTREAM TROUGH OVER THE CONUS. COMPARED WITH
YESTERDAY`S PREDICTION, THE TROUGH AXIS SHIFTED WESTWARD TO THE CENTRAL AND
WESTERN CONUS. POSITIVE 500-HPA HEIGHT ANOMALIES ARE FORECAST OFF THE WEST
COAST, WITH NEGATIVE 500-HPA HEIGHT ANOMALIES FORECAST ACROSS THE CONUS. THE
ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE FORECAST
DOMAIN. TODAY`S OFFICIAL 500-HPA HEIGHT MANUAL BLEND INCLUDED THE OPERATIONAL
EUROPEAN MODEL SINCE IT IS CONSISTENT WITH ITS ENSEMBLE MEAN SOLUTION.

ABOVE-NORMAL TEMPERATURES ARE FAVORED FOR THE SOUTHWESTERN AND NORTHEASTERN
CONUS NEAR THE FORECAST RIDGE AND AHEAD OF THE TROUGH, RESPECTIVELY.
BELOW-NORMAL TEMPERATURES ARE EXPECTED OVER THE NORTHERN CONUS DUE TO ANOMALOUS
NORTHERLY FLOW.  ABOVE-NORMAL TEMPERATURE PROBABILITIES ARE ENHANCED FOR
ALASKA, THE ALEUTIANS AND THE PANHANDLE IN ASSOCIATION WITH SURFACE
SOUTHWESTERLY FLOW, EAST OF A LOW PRESSURE SYSTEM OVER THE BERING SEA.

THE AMPLIFIED TROUGH INCREASES CHANCE FOR ABOVE-MEDIAN PRECIPITATION FOR THE
ROCKIES, WHILE UP-SLOPE FLOW FAVORS ABOVE-MEDIAN PRECIPITATION ACROSS THE HIGH
PLAINS. ABOVE-MEDIAN PRECIPITATION IS PREDICTED OVER THE NORTHEASTERN CONUS AND
OHIO VALLEY, TENNESSEE VALLEY AND PART OF EAST GULF COAST REGION IN ASSOCIATION
WITH THE ACTIVE LOWER-LEVEL JET AHEAD OF THE TROUGH. BELOW-MEDIAN PRECIPITATION
CHANCES ARE ENHANCED FOR THE SOUTHWESTERN CONUS, THE CENTRAL AND SOUTH GREAT
PLAINS AND THE LOWER MISSISSIPPI VALLEY, UNDER THE INFLUENCE OF THE RIDGE NEAR
THE WEST COAST WHICH LIMITS PACIFIC FLOW. ABOVE-MEDIAN PRECIPITATION CHANCES
ARE ENHANCED ACROSS MOST OF ALASKA AND THE ALEUTIANS, NEAR AND AHEAD OF THE
PREDICTED TROUGH OVER THE BERING SEA.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 20% OF YESTERDAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 7,
20% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 20% OF YESTERDAY`S
12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 7, AND 20% OF TODAY`S OPERATIONAL 0Z
ECMWF CENTERED ON DAY 8


MODEL OF THE DAY: NO PREFERENCE

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG ENSEMBLE MEANS.

8-14 DAY OUTLOOK FOR DEC 27, 2014 - JAN 02, 2015

THE ENSEMBLE MEAN PREDICTIONS OF THE 500-HPA HEIGHT PATTERN FOR THE WEEK-2
PERIOD ARE IN FAIR AGREEMENT OVER NORTH AMERICA. A RIDGE IS PREDICTED OVER THE
GULF OF ALASKA, ASSOCIATED WITH POSITIVE 500-HPA HEIGHT ANOMALIES OFF THE WEST
COAST. A HIGH AMPLITUDE TROUGH IS ANTICIPATED OVER THE CENTRAL AND EASTERN
CONUS, WITH NEGATIVE 500-HPA HEIGHT ANOMALIES ACROSS MOST OF THE CONUS. THE
ENSEMBLE SPAGHETTI DIAGRAMS INDICATE MODERATE SPREAD ACROSS THE FORECAST
DOMAIN.

THERE ARE ENHANCED PROBABILITIES FOR NEAR- TO ABOVE-NORMAL TEMPERATURES FOR THE
CALIFORNIA COAST, AHEAD OF THE RIDGE OFF THE WEST COAST. BELOW-NORMAL
TEMPERATURES ARE FAVORED FOR MUCH OF THE NORTHERN, CENTRAL AND EASTERN CONUS
DUE TO ANOMALOUS NORTHERLY FLOW. THERE ARE ENHANCED PROBABILITIES FOR NEAR- TO
ABOVE-NORMAL TEMPERATURES FOR ALASKA, ALEUTIANS AND THE PANHANDLE RELATED TO
THE SOUTHWESTERLY WINDS, EAST OF THE SURFACE LOW PRESSURE OVER THE BERING SEA.

BELOW-MEDIAN PRECIPITATION IS FAVORED FOR THE WESTERN CONUS IN ASSOCIATION WITH
THE FORECAST RIDGE OFF THE WEST COAST. THERE ARE ENHANCED PROBABILITIES OF
NEAR- TO BELOW-MEDIAN PRECIPITATION FOR THE MIDDLE MISSISSIPPI VALLEY
CONSISTENT WITH THE BIAS CORRECTED PRECIPITATION FROM THE ECMWF ENSEMBLES AND
GFS ENSEMBLES. NEAR- TO ABOVE-MEDIAN PRECIPITATION IS FAVORED FOR THE NORTHERN
ROCKIES, THE GREAT PLAINS, IN ASSOCIATION WITH EXPECTED UP-SLOPE FLOW OVER THE
SURFACE. ABOVE-MEDIAN PRECIPITATION IS ALSO FAVORED FOR THE SOUTHEASTERN CONUS
AND NEW ENGLAND, AHEAD OF THE TROUGH. THERE ARE ENHANCED PROBABILITIES OF NEAR-
TO ABOVE-MEDIAN PRECIPITATION FOR WEST ALASKA AND THE ALEUTIANS.

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, 20% OF YESTERDAY`S GFS SUPERENSEMBLE MEAN CENTERED ON DAY 10, 20% OF
TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 20% OF YESTERDAY`S
12Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 10


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOUT AVERAGE, 3 OUT OF 5, DUE
TO FAIR MODEL AGREEMENT WITH SOME DISAGREEMENT BETWEEN TOOLS FROM THE ECMWF AND
GEFS ENSEMBLES ACROSS THE EASTERN CONUS.

FORECASTER: QIN GINGER ZHANG

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
JANUARY 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:
19911230 - 19591225 - 19931214 - 20061210 - 19871129


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:
19591225 - 19871128 - 19911231 - 20031224 - 19941228


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 25 - 29 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 27, 2014 - JAN 02, 2015

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