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FXUS06 KWBC 231902
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EDT WED MAY 23 2018

6-10 DAY OUTLOOK FOR MAY 29 - JUN 02, 2018

THE 0Z GFS AND 0Z ECMWF ENSEMBLE MEANS AND THEIR DETERMINISTIC MODEL SOLUTIONS
ARE IN GOOD AGREEMENT ON THE 500-HPA LONGWAVE FEATURES INCLUDING: A WEAKENING
UPPER-LEVEL LOW OVER THE SOUTHEAST, A STRENGTHENING UPPER-LEVEL RIDGE OVER THE
HIGHER LATITUDES OF THE CENTRAL AND EASTERN U.S., AND AN UPPER-LEVEL TROUGH OF
VARYING AMPLITUDE ENTERING THE WESTERN U.S. THE 0Z ECMWF ENSEMBLE MEAN AND ITS
DETERMINISTIC RUN HAVE THE MOST AMPLIFIED TROUGH ENTERING THE WESTERN U.S.
DURING THIS 5-DAY PERIOD, WHICH  IS PREFERRED SINCE THIS SOLUTION TELECONNECTS
WELL WITH A POSITIVE 500-HPA HEIGHT ANOMALY CENTER SOUTH OF THE ALEUTIANS.

ABOVE-NORMAL TEMPERATURES ARE FAVORED THROUGHOUT THE CONUS BUT FORECAST
CONFIDENCE IS LOWER IN A COUPLE OF AREAS. WIDESPREAD RAINFALL EXPECTED AT LEAST
EARLY IN THE PERIOD REDUCE PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS
THE SOUTHEAST, WHILE AN UPPER-LEVEL TROUGH ENTERING THE WESTERN U.S. DECREASES
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THIS REGION. THE HIGHEST
PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ARE FORECAST ACROSS THE GREAT
PLAINS WHERE THE DETERMINISTIC 0Z ECMWF MODEL INDICATES 500-HPA HEIGHTS
INCREASING TO 594DM OVER THE SOUTH-CENTRAL CONUS BY JUNE 1.

AN UPPER-LEVEL LOW EARLY IN THE PERIOD AND THE POTENTIAL REMNANTS OF THE FIRST
TROPICAL CYCLONE OF THE SEASON INCREASE CHANCES FOR ABOVE-NORMAL PRECIPITATION
FROM THE GULF COAST NORTH TO THE OHIO VALLEY AND MID-ATLANTIC. THE GFS AND
ECMWF ENSEMBLE MEANS INDICATE LOCALLY MORE THAN 2 INCHES OF RAINFALL ACROSS THE
SOUTHEAST DURING THIS 5-DAY PERIOD. A BUILDING RIDGE ALOFT ENHANCE ODDS FOR
BELOW-NORMAL PRECIPITATION FROM TEXAS NORTHEAST TO THE GREAT LAKES AND
NORTHEAST. DOWNSTREAM OF AN UPPER-LEVEL TROUGH, ABOVE-NORMAL PRECIPITATION IS
FAVORED ACROSS PARTS OF THE GREAT BASIN, NORTHERN AND CENTRAL ROCKIES, AND THE
NORTHERN AND CENTRAL GREAT PLAINS. INCREASED CHANCES OF BELOW-NORMAL
PRECIPITATION ARE FORECAST FOR THE PACIFIC NORTHWEST, DUE TO UPSTREAM RIDGING
OVER THE GULF OF ALASKA.

AN UPPER-LEVEL TROUGH UPSTREAM OVER THE BERING SEA INCREASES CHANCES FOR
ABOVE-NORMAL PRECIPITATION ACROSS SOUTHWEST ALASKA AND THE ALEUTIANS, WHILE
MEAN RIDGING ALOFT TILTS THE ODDS TO BELOW-NORMAL PRECIPITATION ACROSS EASTERN
MAINLAND ALASKA. TEMPERATURE TOOLS DERIVED FROM THE DYNAMICAL MODELS SUPPORT
BELOW-NORMAL TEMPERATURES ACROSS SOUTHEAST MAINLAND ALASKA. NEAR TO ABOVE
NORMAL TEMPERATURES ARE FAVORED FOR THE ALEUTIANS AND WESTERN COASTAL ALASKA,
IN PART DUE TO ABOVE NORMAL SEA SURFACE TEMPERATURES.

THE OFFICIAL 6-10 DAY 500-HPA HEIGHT BLEND CONSISTS OF 25% OF TODAY`S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 8, 50% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 8, AND 25% OF TODAY`S OPERATIONAL 0Z ECMWF CENTERED ON DAY 8


FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
EXCELLENT AGREEMENT AMONG THE TEMPERATURE TOOLS AND GOOD AGREEMENT BETWEEN THE
ANALOG PRECIPITATION TOOLS AND DYNAMICAL MODEL GUIDANCE.

8-14 DAY OUTLOOK FOR MAY 31 - JUN 06, 2018

EARLY IN WEEK-2, THE PREFERRED ECMWF MODEL INDICATES AN AMPLIFIED 500-HPA
TROUGH ENTERING THE WESTERN U.S. DOWNSTREAM OF THIS UPPER-LEVEL TROUGH, 500-HPA
HEIGHTS ARE FORECAST TO INCREASE AND ARE LIKELY TO EXCEED 588DM FROM THE
SOUTHERN GREAT PLAINS NORTHEAST TO THE MIDDLE MISSISSIPPI VALLEY. THIS EVOLVING
LONGWAVE PATTERN YIELDS THE HIGHEST ODDS FOR ABOVE NORMAL TEMPERATURES ACROSS
THE CENTRAL AND SOUTHERN GREAT PLAINS WHERE AN INCREASING RISK OF AN EARLY
SEASON HEAT WAVE EXISTS. FOLLOWING A WET EARLY SPRING, PRECIPITATION HAS
AVERAGED BELOW NORMAL ACROSS THE EASTERN THIRD OF TEXAS WHERE TOPSOILS ARE
DRYING OUT. SOIL MOISTURE CURRENTLY RANKS IN THE LOWEST 20TH PERCENTILE ACROSS
PARTS OF THE CENTRAL AND SOUTHERN GREAT PLAINS. THE LOW SOIL MOISTURE ALSO
SUPPORTS HIGHER PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES ACROSS THE CENTRAL
AND SOUTHERN GREAT PLAINS. ELSEWHERE, MUCH OF THE CAROLINAS, GEORGIA, AND
FLORIDA HAVE EXPERIENCED A VERY WET MAY. ALTHOUGH THE LONGWAVE PATTERN SUPPORTS
ABOVE-NORMAL TEMPERATURES ACROSS THE SOUTHEASTERN U.S., THE INCREASINGLY WET
TOPSOIL LIMITS THE PROBABILITIES FOR ABOVE-NORMAL TEMPERATURES. NEAR NORMAL
TEMPERATURES ARE FAVORED FOR PARTS OF CALIFORNIA BASED ON THE EXPECTATION OF AN
AMPLIFIED TROUGH ENTERING THE WESTERN U.S. DURING WEEK-2 AND SUPPORT FROM THE
ANALOG TEMPERATURE TOOLS.

FORECAST CONFIDENCE IS MUCH LOWER IN THE PRECIPITATION OUTLOOK SINCE THE
UPPER-LEVEL LOW OVER THE SOUTHEAST, RESPONSIBLE FOR A MULTI-DAY HEAVY RAINFALL
EVENT PRECEDING THIS PERIOD, IS EXPECTED TO DISSIPATE EARLY IN WEEK-2. AN
UPPER-LEVEL TROUGH, EARLY DURING WEEK-2, FAVORS ABOVE-NORMAL PRECIPITATION FROM
THE GREAT BASIN NORTHEAST TO THE NORTHERN GREAT PLAINS. BELOW-NORMAL
PRECIPITATION IS FAVORED FROM KANSAS SOUTH TO TEXAS DUE TO ANOMALOUS RIDGING
ALOFT AND THE EXPECTATION THAT A STRONG CAPPING INVERSION WILL INHIBIT
CONVECTION.

THE UPPER-LEVEL TROUGH INITIALLY OVER THE BERING SEA TILTS THE ODDS TO ABOVE
NORMAL PRECIPITATION ACROSS THE ALEUTIANS AND WESTERN ALASKA, WHILE AN
UPPER-LEVEL RIDGE INCREASES CHANCES FOR BELOW NORMAL PRECIPITATION ACROSS
EASTERN MAINLAND ALASKA. THE TEMPERATURE OUTLOOK IS BASED ON DYNAMICAL MODEL
CONSENSUS AND SEA SURFACE ANOMALY CONSIDERATIONS.

THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 25% OF TODAY`S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, AND 75% OF TODAY`S 0Z EUROPEAN ENSEMBLE MEAN
CENTERED ON DAY 11


FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO GOOD
AGREEMENT IN THE TEMPERATURE OUTLOOK OFFSET BY INCREASED UNCERTAINTY IN THE
PRECIPITATION OUTLOOK.

FORECASTER: BRAD PUGH

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
JUNE 21.

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:
19910513 - 19950602 - 19610603 - 19700522 - 19940523


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:
19910513 - 19610604 - 20070512 - 19950601 - 19870504


6-10 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 29 - JUN 02, 2018

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



8-14 DAY OUTLOOK TABLE
OUTLOOK FOR MAY 31 - JUN 06, 2018

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