Prognostic Meteorological Discussion
Issued by NWS

Home | Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXUS06 KWBC 202002
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST MON FEBRUARY 20 2017

6-10 DAY OUTLOOK FOR FEB 26 - MAR 02, 2017

TODAY`S MODEL SOLUTIONS ARE IN GOOD AGREEMENT ON A HIGHLY AMPLIFIED FORECAST
PATTERN OVER NORTH AMERICA. THE OFFICIAL 500-HPA MANUAL HEIGHT BLEND DEPICTS A
BLOCKING PATTERN OVER THE NORTHEAST PACIFIC WITH DOWNSTREAM TROUGHING OVER
WEST-CENTRAL NORTH AMERICA. ANOMALOUS RIDGING IS FORECAST OVER THE EASTERN
SEABOARD EXTENDING INTO THE WESTERN ATLANTIC. THIS WELL-TELECONNECTED PATTERN
IS FURTHER SUPPORTED BY VARIOUS STATISTICAL TOOLS, INCREASING FORECAST
CONFIDENCE.

A DISTINCT COLD NORTHWEST/WARM SOUTHEAST PATTERN IS FORECAST, WITH MAXIMUM
PROBABILITIES EXCEEDING 80 PERCENT IN PARTS OF THE INTERIOR NORTHWEST AND
SOUTHEAST, RESPECTIVELY. UNCERTAINTY IS THE GREATEST FROM THE MIDWEST TO THE
NORTHEAST DURING THIS PERIOD, SINCE THERE IS SOME RUN-TO-RUN VARIABILITY ON THE
POSITION OF THE MEAN FRONTAL BOUNDARY. THE 12Z DETERMINISTIC GFS, FOR EXAMPLE,
KEEPS THE MEAN FRONTAL ZONE THROUGH THE NORTHEAST, WHICH WOULD RESULT IN A
COLDER SOLUTION FOR THE GREAT LAKES.

THE PRECIPITATION OUTLOOK IS EASILY INFERRED FROM THE FORECAST HEIGHT PATTERN
OVER THE EASTERN CONUS, DOWNSTREAM OF ANOMALOUS FORECAST TROUGHING CENTERED
NEAR THE ROCKIES. SUCH A PATTERN IS CONDUCIVE TO AN ACTIVE STORM TRACK FROM THE
LEE OF THE ROCKIES NORTHEASTWARD. GIVEN THE TIME OF YEAR, ONE OR TWO CLASSIC
LATE WINTER/SPRING CYCLONES ARE POSSIBLE, WITH ATTENDANT HEAVY SNOW, HEAVY
RAIN, HIGH WINDS, AND SEVERE WEATHER, ALL IN THE TYPICAL REGIONS RELATIVE TO
THE STORM TRACK. THE PRECIPITATION OUTLOOK IS MORE UNCERTAIN OVER THE WESTERN
CONUS, WHERE A TRANSITION IS LIKELY EARLY IN THE PERIOD. WHILE THE
PERIOD-AVERAGE HEIGHT PATTERN DEPICT ANOMALOUS NORTHERLY MID-LEVEL FLOW, A
FAIRLY DRY PATTERN, TRANSIENT TROUGHING AT THE BEGINNING OF THE PERIOD RESULTS
IN NEAR-TO-ABOVE MEDIAN PRECIPITATION BEING FAVORED.

THE FORECAST BLOCKING PATTERN OVER THE NORTHEAST PACIFIC IS EXPECTED TO LEAD TO
ANOMALOUS NORTHWESTERLY MID-LEVEL FLOW OVER ALASKA. ABOVE-MEDIAN PRECIPITATION
IS STRONGLY FAVORED OVER MUCH OF MAINLAND ALASKA, WHILE BELOW-MEDIAN
PRECIPITATION IS FAVORED OVER THE CLIMATOLOGICALLY ACTIVE SOUTH COAST OF ALASKA.

TODAY`S OFFICIAL 500-HPA BLEND CONSISTS OF 15% OF TODAY`S 0Z GFS ENSEMBLE MEAN
CENTERED ON DAY 8, 20% OF TODAY`S 6Z GFS ENSEMBLE MEAN CENTERED ON DAY 8, 5% OF
TODAY`S OPERATIONAL 0Z GFS CENTERED ON DAY 8, 10% OF TODAY`S OPERATIONAL 6Z GFS
CENTERED ON DAY 8, 40% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8,
AND 10% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: MUCH ABOVE AVERAGE, 5 OUT OF 5,
DUE TO GOOD MODEL AGREEMENT ON AN AMPLIFIED PATTERN AND AGREEMENT AMONG THE
DYNAMICAL AND STATISTICAL GUIDANCE.

8-14 DAY OUTLOOK FOR FEB 28 - MAR 06, 2017

THE WEEK-2 OUTLOOK IS BROADLY SIMILAR TO THE 6-10 DAY OUTLOOK, BUT WITH SOME
DIFFERENCES. THERE IS A NOTABLE RETROGRESSION OF THE STRONG POSITIVE HEIGHT
ANOMALY FORECAST OVER THE NORTHEAST PACIFIC DURING THE 6-10 DAY PERIOD TO THE
BERING SEA DURING THE WEEK-2 PERIOD. TELECONNECTIONS UPON THIS CENTER OF ACTION
REVEAL A PATTERN ONLY IN FAIR AGREEMENT WITH THE OFFICIAL 500-HPA HEIGHT MANUAL
BLEND. ADDITIONALLY, RECENT RUNS OF THE GEFS SHOW A TRANSITION TO A MORE
NEGATIVE AO/NAO PHASE BY THE END OF WEEK-2, THOUGH THAT HAS BEEN A NOTABLE BIAS
THIS WINTER.

THE RESULTING TEMPERATURE OUTLOOK IS VERY SIMILAR TO THAT FOR THE 6-10 DAY
PERIOD, BUT WITH SOME COOLING TREND NOTED FROM THE UPPER MIDWEST TO THE
NORTHEAST, AS WELL AS OVER SOUTHEASTERN ALASKA. FOR A WEEK-2 OUTLOOK, THE
MAGNITUDE OF THESE TEMPERATURE PROBABILITIES REFLECT A HIGH CONFIDENCE OUTLOOK.

THE PRECIPITATION OUTLOOK IS ALMOST UNCHANGED FROM THE 6-10 DAY PERIOD, FURTHER
HIGHLIGHTING THE APPARENT STABILITY OF THIS PATTERN. THERE IS, HOWEVER, A
TENDENCY TOWARD DRIER-THAN-AVERAGE CONDITIONS OVER PARTS OF THE WEST COAST
DURING WEEK-2. THIS IS CONSISTENT WITH THE POSITION OF THE UPSTREAM FORECAST
RIDGE AXIS. TELECONNECTIONS UPON THE FORECAST POSITIVE HEIGHT ANOMALY OVER THE
BERING SEA SUGGEST THAT SOME UNDERCUTTING OF THE RIDGE IS POSSIBLE, WHICH WOULD
RESULT IN A WETTER SOLUTION FOR THE WEST COAST. THIS IS SOMETHING THAT WILL BE
MONITORED CLOSELY THROUGHOUT THE WEEK.

THE OFFICIAL 8-14 DAY HEIGHT PROG CONSISTS OF: 15% OF TODAY`S 0Z GFS ENSEMBLE
MEAN CENTERED ON DAY 11, 20% 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, AND 50% OF TODAY`S 0Z EUROPEAN ENSEMBLE
MEAN CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: ABOVE AVERAGE, 4 OUT OF 5, DUE
TO FAIRLY GOOD MODEL AGREEMENT OFFSET BY SOME UNCERTAINTY IN THE EVOLUTION OF
THE CIRCULATION PATTERN OVER EASTERN NORTH AMERICA.

FORECASTER: STEPHEN BAXTER

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
MARCH 16

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:
19780207 - 19920131 - 19980214 - 19690212 - 19870214


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:
19780209 - 19690212 - 19980215 - 20040224 - 19920131


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 26 - MAR 02, 2017

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 28 - MAR 06, 2017

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

                           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.