129
FXUS06 KWBC 192039
PMDMRD
PROGNOSTIC DISCUSSION FOR 6 TO 10 AND 8 TO 14 DAY OUTLOOKS
NWS CLIMATE PREDICTION CENTER COLLEGE PARK, MD
300 PM EST TUE FEBRUARY 19 2019
6-10 DAY OUTLOOK FOR FEB 25 - MAR 01, 2019
THE CANADIAN, GFS, AND ECMWF ENSEMBLE MEANS ARE IN EXCELLENT AGREEMENT WITH THE
LONGWAVE 500-HPA PATTERN THROUGHOUT THE NORTHERN HEMISPHERE. THESE ENSEMBLE
MEANS FEATURE A HIGHLY AMPLIFIED UPPER-LEVEL RIDGE OVER MAINLAND ALASKA DURING
THIS 5-DAY PERIOD WITH A HIGH AMPLITUDE, POSITIVELY-TILTED, UPPER-LEVEL TROUGH
EXTENDING FROM HUDSON BAY SOUTHWEST TO THE INTERIOR WEST. A SUBTROPICAL RIDGE
IS FORECAST OVER THE CARIBBEAN ISLANDS. THE MANUAL, 500-HPA HEIGHT BLEND IS
BASED PRIMARILY ON THE ENSEMBLE MEANS FROM THE GEFS AND ECMWF ENSEMBLES. BELOW
NORMAL HEIGHTS ARE FAVORED FOR MUCH OF THE NORTH-CENTRAL CONUS, THE INTERIOR
WEST, THE WESTERN ALEUTIANS, AND PARTS OF THE NORTHEAST. ABOVE NORMAL HEIGHTS
ARE FORECAST FOR MAINLAND ALASKA, THE ALASKA PANHANDLE, AS WELL AS FROM THE
GULF COAST OF THE CONUS, ACROSS THE SOUTHEAST, AND EXTENDING NORTHWARD TO
SOUTHERN NEW ENGLAND.
THE HIGH AMPLITUDE RIDGE OVER MAINLAND ALASKA AND ARCTIC HIGH PRESSURE CENTERED
IN WESTERN CANADA ARE LIKELY TO MAINTAIN AN ANOMALOUSLY COLD PATTERN ACROSS
MOST OF THE CENTRAL AND WESTERN CONUS. BELOW NORMAL TEMPERATURES ARE ALSO
FAVORED TO EXTEND EASTWARD TO PARTS OF THE NORTHEAST WITH TIME BUT WITH
RELATIVELY LOWER CONFIDENCE. THE HIGHEST ODDS FOR BELOW NORMAL TEMPERATURES
(GREATER THAN 90 PERCENT) ARE FORECAST ACROSS THE NORTHERN AND CENTRAL GREAT
PLAINS DUE TO EXCELLENT DYNAMICAL AND STATISTICAL TOOL AGREEMENT. THE SOUTHERN
EXTENT OF THE ANOMALOUS COLD IS SOMEWHAT UNCERTAIN, BUT TELECONNECTIONS UPON
THE LARGE POSITIVE 500-HPA CENTER OVER EASTERN MAINLAND ALASKA FAVOR BELOW
NORMAL TEMPERATURES EXTENDING SOUTHWARD ACROSS THE SOUTHERN PLAINS. THE
SUBTROPICAL RIDGE FORECAST OVER THE CARIBBEAN ISLANDS FAVORS ABOVE NORMAL
TEMPERATURES FOR MUCH OF THE SOUTHEAST. ABOVE NORMAL TEMPERATURES ARE ALSO
FAVORED FOR MAINLAND ALASKA AND THE ALEUTIANS UNDERNEATH ANOMALOUS RIDGING AND
SOUTHERLY FLOW AHEAD OF A TROUGH FORECAST OVER THE WESTERN BERING SEA. HOWEVER,
THERE ARE ENHANCED PROBABILITIES OF BELOW NORMAL TEMPERATURES FOR PARTS OF THE
ALASKA PANHANDLE UNDERNEATH ANOMALOUS NORTHEASTERLY 500-HPA FLOW DOWNSTREAM OF
THE RIDGE AXIS.
ABOVE NORMAL PRECIPITATION IS FAVORED SOUTH AND EAST OF THE UPPER-LEVEL TROUGH
AXIS ACROSS THE GULF COAST AND THE EASTERN SEABOARD. THE HIGHEST PROBABILITIES
OF ABOVE NORMAL PRECIPITATION (GREATER THAN 60 PERCENT) ARE INDICATED FOR PARTS
OF THE CENTRAL GULF COAST REGION NEAR A POTENTIAL MEAN FRONTAL BOUNDARY.
POTENTIAL SHORTWAVE TROUGHS AND UPSLOPE FLOW TILT THE ODDS TO ABOVE NORMAL
PRECIPITATION ACROSS PARTS OF THE NORTHERN AND CENTRAL PLAINS. BELOW NORMAL
PRECIPITATION IS FAVORED ALONG THE WEST COAST AND SOUTHWEST DOWNSTREAM OF WEAK
RIDGING OFF THE COAST. STRONG RIDGING AND ASSOCIATED OFFSHORE FLOW LEAD TO
ENHANCED PROBABILITIES OF BELOW NORMAL PRECIPITATION FOR EASTERN PORTIONS OF
MAINLAND ALASKA AND THE ALASKA PANHANDLE. CONVERSELY ABOVE NORMAL PRECIPITATION
IS FAVORED FOR WESTERN ALASKA UNDERNEATH MOIST SOUTHERLY FLOW AHEAD OF THE
TROUGH FORECAST OVER THE WESTERN BERING SEA.
THE OFFICIAL 6-10 DAY 500-HPA HEIGHT 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 6Z GFS CENTERED ON DAY 8, 35% OF TODAY'S 0Z
EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 8, 10% OF TODAY'S OPERATIONAL 0Z ECMWF
CENTERED ON DAY 8, AND 15% OF TODAY'S 0Z CANADIAN ENSEMBLE MEAN CENTERED ON DAY
8
FORECAST CONFIDENCE FOR THE 6-10 DAY PERIOD: ABOVE AVERAGE, 4 OUT OF 5, DUE TO
GOOD AGREEMENT AMONG THE ENSEMBLE MEANS IN A HIGHLY AMPLIFIED LONGWAVE PATTERN.
8-14 DAY OUTLOOK FOR FEB 27 - MAR 05, 2019
THE ENSEMBLE MEANS MAINTAIN A HIGH AMPLITUDE LONGWAVE 500-HPA RIDGE OVER MUCH
OF ALASKA DURING WEEK-2 WITH AN EASTWARD PROGRESSION OF AN ANOMALOUS TROUGH
DOWNSTREAM ACROSS EAST-CENTRAL NORTH AMERICA. FARTHER TO THE SOUTH, LOW
AMPLITUDE PACIFIC FLOW IS FORECAST TO UNDERCUT THE ALASKA RIDGE ACROSS MUCH OF
THE WEST COAST OF THE CONUS (ALTHOUGH MODEL SPREAD AND UNCERTAINTY ARE
RELATIVELY HIGH ACROSS THIS REGION). THE WEEK-2 MANUAL 500-HPA HEIGHT BLEND IS
BASED ALMOST ENTIRELY ON THE ENSEMBLE MEAN SOLUTIONS FROM THE GEFS, ECMWF, AND
CANADIAN MODELS. ABOVE NORMAL HEIGHTS ARE FAVORED ACROSS ALASKA (WITH THE
EXCEPTION OF THE WESTERN ALEUTIANS). BELOW NORMAL HEIGHTS ARE FORECAST FROM THE
NORTHERN ROCKIES EASTWARD ACROSS THE NORTHERN AND CENTRAL PLAINS, GREAT LAKES,
AND PARTS OF THE NORTHEAST. NEAR TO SLIGHTLY ABOVE NORMAL HEIGHTS ARE FAVORED
THE SOUTHERN TIER OF THE CONUS AND THE WEST COAST.
BELOW NORMAL TEMPERATURES ARE LIKELY FOR MUCH OF THE CONUS DURING WEEK-2
UNDERNEATH A MEAN ANOMALOUS TROUGH. THE HIGHEST PROBABILITIES OF BELOW NORMAL
TEMPERATURES (GREATER THAN 90 PERCENT) CONTINUE FOR PARTS OF THE NORTH-CENTRAL
CONUS NEAR THE PREDICTED MEAN TROUGH AXIS. LOWER ODDS FOR BELOW NORMAL
TEMPERATURES ARE FORECAST ALONG THE WEST COAST DURING WEEK-2 COMPARED TO DAYS
6-10 AS THIS REGION IS LIKELY TO EXPERIENCE A WARMING TREND. LOWER CONFIDENCE
IN THE TEMPERATURE OUTLOOK ALSO EXISTS ACROSS THE SOUTHEAST AS MODEL SOLUTIONS
VARY ON WHEN THE PERSISTENT, ANOMALOUS RIDGE WEAKENS. GIVEN THAT MEAN ABOVE
NORMAL HEIGHTS ARE LIKELY ACROSS THE SOUTHEAST, NEAR TO ABOVE NORMAL
TEMPERATURES ARE FAVORED FROM THE FLORIDA PENINSULA NORTHWARD TO THE CAROLINA
COAST. DUE TO PERSISTENT ANOMALOUS RIDGING EXPECTED ACROSS MOST OF ALASKA,
ABOVE NORMAL TEMPERATURES ARE FAVORED ACROSS THE MAINLAND AND THE ALEUTIANS.
HOWEVER THERE ARE ENHANCED PROBABILITIES OF BELOW NORMAL TEMPERATURES ACROSS
MUCH OF THE PANHANDLE UNDERNEATH ANOMALOUS NORTHEASTERLY 500-HPA FLOW AHEAD OF
THE RIDGE AXIS.
ABOVE NORMAL PRECIPITATION CONTINUES TO BE FAVORED ALONG THE EAST AND GULF
COASTS IN ASSOCIATION WITH THE MEAN TROUGH PREDICTED ACROSS EAST-CENTRAL NORTH
AMERICA. THE HIGHEST ODDS OF ABOVE NORMAL PRECIPITATION (GREATER THAN 50
PERCENT) IS FORECAST FOR PARTS OF THE SOUTHEAST WHERE A FRONT IS LIKELY TO SLOW
AND PERHAPS STALL DURING WEEK-2. NEAR TO BELOW NORMAL PRECIPITATION IS FAVORED
THROUGHOUT THE MIDDLE AND UPPER MISSISSIPPI VALLEY AS WELL AS EASTERN PORTIONS
OF THE NORTHERN AND CENTRAL PLAINS DUE TO A SPRAWLING AREA OF SURFACE HIGH
PRESSURE EXPECTED ACROSS THESE REGIONS. HOWEVER, THERE IS A SLIGHT TILT IN THE
ODDS FOR ABOVE NORMAL PRECIPITATION ACROSS THE NORTHERN HIGH PLAINS RELATED TO
POTENTIAL UPSLOPE FLOW. DYNAMICAL AND STATISTICAL MODEL GUIDANCE ARE IN
RELATIVELY GOOD AGREEMENT IN FAVORING BELOW NORMAL PRECIPITATION ACROSS THE
DESERT SOUTHWEST AS WELL AS THE PACIFIC NORTHWEST. HOWEVER, NEAR TO ABOVE
NORMAL PRECIPITATION IS FAVORED FOR NORTHERN CALIFORNIA DUE TO THE POTENTIAL
FOR PACIFIC FLOW TO UNDERCUT STRONG RIDGING FARTHER TO THE NORTH OVER ALASKA.
THE PREDICTED ALASKAN RIDGE FAVORS BELOW NORMAL PRECIPITATION ACROSS THE ALASKA
PANHANDLE AND MOST OF EASTERN MAINLAND ALASKA. FORECAST ANOMALOUS SOUTHERLY
FLOW BEHIND THE RIDGE AXIS LEADS TO CONTINUED ELEVATED PROBABILITIES OF ABOVE
NORMAL PRECIPITATION FOR WESTERN ALASKA.
THE OFFICIAL 8-14 DAY 500-HPA HEIGHT BLEND CONSISTS OF: 15% OF TODAY'S 0Z GFS
ENSEMBLE MEAN CENTERED ON DAY 11, 30% OF TODAY'S 6Z GFS ENSEMBLE MEAN CENTERED
ON DAY 11, 5% OF TODAY'S OPERATIONAL 6Z GFS CENTERED ON DAY 11, 35% OF TODAY'S
0Z EUROPEAN ENSEMBLE MEAN CENTERED ON DAY 11, AND 15% OF TODAY'S 0Z CANADIAN
ENSEMBLE MEAN CENTERED ON DAY 11
FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD: AVERAGE, 3 OUT OF 5, DUE TO VERY
GOOD AGREEMENT AMONG THE TEMPERATURE TOOLS OVER THE NORTH-CENTRAL CONUS AND
MOST OF ALASKA OFFSET BY MODEL UNCERTAINTY AS TO THE SOUTHERN EXTENT OF THE
TROUGH OVER EAST-CENTRAL NORTH AMERICA AS WELL AS UNCERTAINTY RELATED TO THE
EXTENT OF UNDERCUTTING PACIFIC FLOW OVER THE WESTERN CONUS.
FORECASTER: SCOTT H
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 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:
20010208 - 19850303 - 20060218 - 20090213 - 19530301
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:
20010209 - 20060218 - 19850303 - 20090213 - 19530301
6-10 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 25 - MAR 01, 2019
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF B B
SRN CALIF B B IDAHO B N NEVADA B B
W MONTANA B A E MONTANA B A WYOMING B A
UTAH B N ARIZONA B B COLORADO B A
NEW MEXICO B B N DAKOTA B N S DAKOTA B A
NEBRASKA B A KANSAS B N OKLAHOMA B N
N TEXAS B N S TEXAS B A W TEXAS B B
MINNESOTA B N IOWA B A MISSOURI B N
ARKANSAS B N LOUISIANA N A WISCONSIN B A
ILLINOIS B N MISSISSIPPI N A MICHIGAN B A
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE N A ALABAMA A A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN N A NEW JERSEY N A W VIRGINIA N A
MARYLAND N A DELAWARE N A VIRGINIA N A
N CAROLINA N 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 A A AK SO COAST A A AK PNHDL B B
8-14 DAY OUTLOOK TABLE
OUTLOOK FOR FEB 27 - MAR 05, 2019
STATE TEMP PCPN STATE TEMP PCPN STATE TEMP PCPN
WASHINGTON B B OREGON B B NRN CALIF B N
SRN CALIF B B IDAHO B B NEVADA B B
W MONTANA B N E MONTANA B A WYOMING B N
UTAH B B ARIZONA B B COLORADO B N
NEW MEXICO B B N DAKOTA B B S DAKOTA B B
NEBRASKA B B KANSAS B B OKLAHOMA B B
N TEXAS B N S TEXAS B A W TEXAS B N
MINNESOTA B B IOWA B B MISSOURI B B
ARKANSAS B N LOUISIANA B A WISCONSIN B B
ILLINOIS B B MISSISSIPPI B A MICHIGAN B N
INDIANA B N OHIO B N KENTUCKY B N
TENNESSEE B N ALABAMA B A NEW YORK B A
VERMONT B A NEW HAMP B A MAINE B A
MASS B A CONN B A RHODE IS B A
PENN B A NEW JERSEY B A W VIRGINIA B A
MARYLAND B A DELAWARE B A VIRGINIA B A
N CAROLINA B A S CAROLINA B A GEORGIA B A
FL PNHDL N 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 A A AK SO COAST A A 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.
$$