Prognostic Meteorological Discussion
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FXUS06 KWBC 242002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST MON NOVEMBER 24 2014

6-10 DAY OUTLOOK FOR NOV 30 - DEC 04, 2014

THERE IS GOOD AGREEMENT AMONG TODAY`S MODEL FORECASTS OF THE 6-10 DAY MEAN
500-HPA HEIGHTS OVER NORTH AMERICA. A RIDGE IS FORECAST TO BE OVER THE
NORTHEASTERN CONUS WITH A TROUGH OVER THE WEST. STRONG ZONAL 500-HPA FLOW IS
FORECAST JUST NORTH OF THE U.S. CANADIAN BORDER, CUTTING OFF COLD AIR FROM THE
WESTERN TROUGH. THE 500-HPA HEIGHTS OVER WEST-CENTRAL CANADA ARE FORECAST TO BE
BELOW NORMAL, SETTING UP A SHARP GRADIENT BETWEEN THE EXPECTED COLD AIR OVER
WESTERN AND CENTRAL CANADA, EXTENDING INTO EASTERN ALASKA AND RELATIVE MILD AIR
OVER THE CONUS.

ABOVE-NORMAL HEIGHTS OVER THE EASTERN HALF OF THE CONUS LEAD TO ENHANCED
CHANCES OF ABOVE-NORMAL TEMPERATURES, ESPECIALLY IN THE SOUTHEAST. MOST MODELS
PREDICT RELATIVELY MILD AIR OVER MUCH OF THE WEST AS WELL, IN SPITE OF THE
FORECAST FOR NEAR- TO BELOW- NORMAL 500-HPA HEIGHTS IN THE TROUGH. A SHARP
GRADIENT JUST TO THE NORTH OF THE BORDER MAKES FOR UNCERTAIN CONDITIONS IN THE
NORTHERN ROCKIES, PARTS OF THE PACIFIC NORTHWEST AND NORTHERN PARTS OF THE
GREAT BASIN, WHERE ANY UNFORESEEN TROUGH AMPLIFICATION MAY ALLOW COLD AIR INTO
THE REGION. BELOW-NORMAL TEMPERATURES ARE FAVORED FOR PARTS OF THE NORTHERN
ROCKY MOUNTAINS EASTWARD TO THE UPPER MISSISSIPPI VALLEY. BELOW-NORMAL
TEMPERATURES ARE FAVORED FOR INTERIOR EASTERN ALASKA UNDER BELOW NORMAL 500-HPA
HEIGHTS, ALTHOUGH NEAR-NORMAL TEMPERATURES ARE MOSTLY FAVORED NEAR THE COASTS,
WITH ABOVE NORMAL TEMPERATURES FAVORED IN THE SOUTHWEST AND THE ALEUTIANS WHERE
ABOVE NORMAL SEA SURFACE TEMPERATURES HAVE RE-EMERGED IN RECENT WEEKS.

ENHANCED WESTERLY FLOW OVER THE PACIFIC LEAD TO ELEVATED CHANCES FOR
ABOVE-MEDIAN PRECIPITATION AMOUNTS FOR MUCH OF THE WESTERN CONUS. EXPECTED
SOUTHWESTERLY FLOW AT 500-HPA SHOULD OPEN MUCH OF THE EAST TO MOISTURE FROM THE
GULF OF MEXICO, ENHANCING CHANCES FOR ABOVE-MEDIAN PRECIPITATION. A RELATIVELY
NARROW REGION OF NEAR- TO BELOW-MEDIAN PRECIPITATION IS EXPECTED TO THE LEE OF
THE ROCKIES WHERE LIMITED MOISTURE SUPPLY IN ZONAL FLOW MAY REDUCE
PRECIPITATION AMOUNTS. THE GFS FAVORS BELOW-MEDIAN PRECIPITATION AMOUNTS IN
MUCH OF ALASKA EXCEPT FOR IN THE ALEUTIANS.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 40% OF TODAY`S 6Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 30% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,
10% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8, AND 20% OF TODAY`S 0Z
CANADIAN ENSEMBLE MEAN CENTERED ON DAY 8


MODEL OF THE DAY: 06Z GEFS MEAN

FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOUT AVERAGE, 3 OUT OF 5, DUE TO
GOOD MODEL AGREEMENT ON AN AMPLIFIED RIDGE IN THE EAST, BUT CONSIDERABLE
UNCERTAINTY ASSOCIATED WITH POSSIBLE INFLUENCE OF COLD AIR IN THE BROAD TROUGH
FORECAST OVER THE WEST.

8-14 DAY OUTLOOK FOR DEC 02 - 08 2014

MODELS FORECASTS STRENGTHEN THE RIDGE PREDICTED OVER THE ATLANTIC, AND SHOW
SUBSTANTIAL POSITIVE ANOMALIES JUST OFF THE NEW ENGLAND COAST. THE MODELS ALSO
BEGIN TO DEVELOP ANOTHER WEAKER RIDGE OVER THE WEST COAST OF NORTH AMERICA. A
BROAD, SHALLOW TROUGH IS FORECAST IN BETWEEN THESE FEATURES, WITH 500-HPA
HEIGHTS MOSTLY FORECAST TO BE NEAR NORMAL OR SLIGHTLY ABOVE NORMAL. EXPECTED
ZONAL UPPER-LEVEL FLOW KEEPS COLD AIR TRAPPED IN CENTRAL CANADA, ALTHOUGH, AS
IN THE 6-10 DAY FORECAST, THERE IS A SHARP GRADIENT IN THE MODEL FORECASTS FOR
TEMPERATURES NEAR THE NORTHERN ROCKIES AND NORTHERN GREAT PLAINS.
TELECONNECTIONS ON THE STRONG NEW ENGLAND RIDGE SUGGEST MUCH COLDER
TEMPERATURES IN THE NORTHERN PLAINS THAN THE MODELS INDICATE. HOWEVER MODELS
ARE IN GOOD AGREEMENT ON THE GENERAL FLOW, SUGGESTING THAT TEMPERATURES WILL BE
RELATIVELY MILD IN ZONAL FLOW. THE CONTRAST IN THESE TWO INDICATORS SUGGEST
UNCERTAINTY IN TEMPERATURES ACROSS THE GREAT PLAINS FOR THE PERIOD.

THE TEMPERATURE AND PRECIPITATION PATTERN IS VERY SIMILAR TO THE PATTERN
PREDICTED IN THE 6-10 DAY PERIOD.  THE REGION OF GREATEST UNCERTAINTY IN
TEMPERATURES FOLLOWS THE MEAN TROUGH AXIS WHICH IS FORECAST TO MOVES FROM THE
WEST COAST TO THE GREAT PLAINS BETWEEN THE 6-10 DAY AND 8-14 DAY PERIOD.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 30% OF TODAY`S 6Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 40% 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 IS: ABOUT AVERAGE, 3 OUT OF 5, DUE
TO FAIRLY GOOD AGREEMENT AMONG THE MODELS, BUT A WITH AN ANTICIPATED SHARP
NORTH-SOUTH GRADIENT IN TEMPERATURES MAKING CONDITIONS UNCERTAIN NEAR THE
EXPECTED LONG-WAVE TROUGH POSITION.

FORECASTER: DAVE UNGER

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
DECEMBER 18

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:
19681126 - 19891127 - 19771127 - 19571109 - 19801120


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:
19681125 - 19771126 - 19821126 - 19801121 - 19581104


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR NOV 30 - DEC 04, 2014

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR DEC 02 - 08 2014

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