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FXUS06 KWBC 182043
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST THU JANUARY 18 2018

6-10 DAY OUTLOOK FOR JAN 24 - 28 2018

TODAY`S ENSEMBLE MEAN SOLUTIONS ARE IN FAIRLY GOOD AGREEMENT ON THE EXPECTED
500-HPA FLOW PATTERN OVER THE FORECAST DOMAIN. ALL OF TODAY`S MODEL SOLUTIONS
FORECAST A RIDGE OVER THE WESTERN ALEUTIANS AND TROUGH OVER MUCH OF MAINLAND
ALASKA. WEAK RIDGING IS EXPECTED FARTHER TO THE EAST OVER WESTERN CANADA AND TO
THE SOUTH OFF THE COAST OF CALIFORNIA. A BROAD TROUGH IS PREDICTED OVER THE
WEST-CENTRAL CONUS. HOWEVER, MODELS DISAGREE ON THE STRENGTH OF THIS TROUGH.
TODAY`S 0Z ECMWF ENSEMBLE MEAN PREDICTS A DEEPER TROUGH IN THE WEST, WHILE THE
LATEST GEFS ENSEMBLE MEANS PREDICT A WEAKER TROUGH, WITH BARELY NEGATIVE HEIGHT
ANOMALIES. TELECONNECTIONS OFF OF THE STRONGEST ANOMALY CENTER IN THE FORECAST
DOMAIN, THE POSITIVE HEIGHT ANOMALY CENTER OVER THE ALEUTIANS, SUPPORT RIDGING
OVER THE SOUTHWEST, IN AGREEMENT WITH THE GEFS. THEREFORE TODAY`S MANUAL
500-HPA BLEND FAVORS THE 6Z GEFS ENSEMBLE MEAN, WITH A WEAKER TROUGH PREDICTED
IN THE WESTERN CONUS.

THE TROUGH OVER MAINLAND ALASKA LEADS TO LARGELY ENHANCED PROBABILITIES OF
BELOW NORMAL TEMPERATURES ACROSS ALASKA. BELOW NORMAL TEMPERATURES ARE ALSO
FAVORED ACROSS MUCH OF THE NORTHWEST CONUS AND INTO THE NORTHERN PLAINS
UNDERNEATH NEAR TO BELOW NORMAL HEIGHTS. RIDGING AND ABOVE NORMAL HEIGHTS TO
THE EAST OF THIS TROUGH FAVOR ABOVE NORMAL TEMPERATURES FOR MUCH OF THE EASTERN
CONUS.

THE POTENTIAL FOR SHORTWAVE TROUGHS TO MOVE INTO THE WESTERN CONUS FROM THE
PACIFIC LEADS TO ENHANCED PROBABILITIES OF ABOVE NORMAL PRECIPITATION ACROSS
MUCH OF THE NORTHWESTERN CONUS EXTENDING EASTWARD TO THE NORTHERN AND CENTRAL
ROCKIES. MOIST FLOW AHEAD OF THE LONGWAVE TROUGH OVER THE WEST-CENTRAL CONUS
FAVORS ABOVE NORMAL PRECIPITATION FOR MUCH OF THE EASTERN CONUS. BELOW NORMAL
PRECIPITATION IS LIKELY FOR MUCH OF WESTERN AND CENTRAL ALASKA UNDERNEATH
NORTHEASTERLY LOW LEVEL FLOW. BELOW NORMAL PRECIPITATION IS FAVORED FOR PARTS
OF THE SOUTHWESTERN CONUS CONSISTENT WITH DYNAMICAL MODEL GUIDANCE FROM THE
GEFS AND ECMWF ENSEMBLES AS WELL AS ANALOGS FROM THE MANUAL BLEND.


THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 99% OF TODAY`S 6Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, AND 1% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO FAIRLY
GOOD AGREEMENT AMONG THE ENSEMBLE MEAN SOLUTIONS OFFSET BY POOR AGREEMENT AMONG
THE TELECONNECTIONS FROM THE VARIOUS HEIGHT ANOMALY CENTERS DEPICTED IN THE
MANUAL 500-HPA HEIGHT BLEND.

8-14 DAY OUTLOOK FOR JAN 26 - FEB 01, 2018

DURING THE WEEK-2 PERIOD, TODAY`S MODELS DEPICT INCREASED 500-HPA SPREAD AND
UNCERTAINTY ACROSS MUCH OF THE FORECAST DOMAIN. A MEAN TROUGH IS FORECAST TO
PERSIST OVER MUCH OF MAINLAND ALASKA WITH RIDGES PREDICTED ON EITHER SIDE OF
THIS FEATURE OVER THE ALEUTIANS AND WESTERN CANADA. FARTHER TO THE SOUTH,
RIDGING IS FORECAST OFF THE WEST COAST OF THE CONUS WHILE A TROUGH IS FORECAST
OVER PARTS OF THE CENTRAL CONUS. A RIDGE IS EXPECTED OVER THE CARIBBEAN
EXTENDING TO PARTS OF THE SOUTHEASTERN CONUS.

THE TEMPERATURE PROBABILITY FORECAST FOR THE 6-10 DAY PERIOD IS VERY SIMILAR TO
THE WEEK-2 PERIOD. DUE TO INCREASED UNCERTAINTY OVER ALASKA AND THE WESTERN
CONUS, PROBABILITIES ARE LOWER, WHILE OVER THE EASTERN U.S. AN INCREASE IN THE
AMPLITUDE OF THE POSITIVE HEIGHT ANOMALIES THERE SUPPORT HIGHER FORECAST
PROBABILITIES.

THE PRECIPITATION PROBABILITY FORECAST FOR THE 6-10 DAY PERIOD IS ALSO SIMILAR
TO THE WEEK-2 PERIOD. A STRONGER LOW LEVEL FLOW FROM THE GULF OF MEXICO
INCREASES PROBABILITIES OF ABOVE NORMAL PRECIPITATION IN PARTS OF THE EASTERN
U.S., AND SLIGHTLY MORE RIDGING IN THE WESTERN CONUS LEADS TO LOWER
PROBABILITIES OF ABOVE NORMAL PRECIPITATION FOR THE PACIFIC NORTHWEST.


THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 50% OF TODAY`S
OPERATIONAL 6Z GFS CENTERED ON DAY 11, AND 50% OF TODAY`S 0Z EUROPEAN ENSEMBLE
MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: BELOW AVERAGE, 2 OUT OF 5, DUE TO
RELATIVELY HIGH MODEL SPREAD AND POOR AGREEMENT AMONG THE SURFACE TOOLS.

FORECASTER: MIKE C

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
FEBRUARY 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:
20010120 - 20060104 - 20030104 - 19860124 - 19950120


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:
20010120 - 20060103 - 19950119 - 19810123 - 19860124


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 24 - 28 2018

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      B    A     NRN CALIF   B    N
SRN CALIF   N    B     IDAHO       B    A     NEVADA      B    A
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        B    B     ARIZONA     N    B     COLORADO    B    B
NEW MEXICO  N    B     N DAKOTA    B    A     S DAKOTA    B    A
NEBRASKA    B    N     KANSAS      N    B     OKLAHOMA    A    N
N TEXAS     N    A     S TEXAS     N    A     W TEXAS     N    B
MINNESOTA   N    A     IOWA        A    A     MISSOURI    A    A
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  B    N
AK ALEUTIAN B    B     AK WESTERN  B    B     AK INT BSN  B    B
AK S INT    B    B     AK SO COAST B    B     AK PNHDL    B    A



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR JAN 26 - FEB 01, 2018

STATE      TEMP PCPN   STATE      TEMP PCPN   STATE      TEMP PCPN
WASHINGTON  B    A     OREGON      B    N     NRN CALIF   B    B
SRN CALIF   N    B     IDAHO       B    A     NEVADA      B    B
W MONTANA   B    A     E MONTANA   B    A     WYOMING     B    A
UTAH        B    B     ARIZONA     N    B     COLORADO    N    N
NEW MEXICO  N    B     N DAKOTA    B    A     S DAKOTA    N    A
NEBRASKA    N    A     KANSAS      A    A     OKLAHOMA    A    A
N TEXAS     A    A     S TEXAS     N    A     W TEXAS     A    B
MINNESOTA   N    A     IOWA        A    A     MISSOURI    A    A
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  B    B
AK ALEUTIAN B    B     AK WESTERN  B    B     AK INT BSN  B    B
AK S INT    B    B     AK SO COAST B    B     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.

$$



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