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FXUS07 KWBC 282000
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST FRI FEB 28 2025
30-DAY OUTLOOK DISCUSSION FOR MARCH 2025
THE MARCH 2025 MONTHLY TEMPERATURE AND PRECIPITATION OUTLOOKS ARE UPDATED WITH
INPUT FROM THE CLIMATE PREDICTION CENTER (CPC) EXTENDED RANGE AND SUBSEASONAL
OUTLOOKS, DYNAMICAL MODEL GUIDANCE FOR WEEK 2 AND WEEKS 3-4, BACKGROUND CLIMATE
STATES SUCH AS THE MADDEN JULIAN OSCILLATION (MJO) AND EL NIñO SOUTHERN
OSCILLATION (ENSO), RECENT CLIMATE FORECAST SYSTEM VERSION 2 (CFSV2) MONTHLY
FORECASTS OF TEMPERATURE AND PRECIPITATION, AND EXPERIMENTAL MONTHLY FORECASTS
OF TEMPERATURE AND PRECIPITATION FROM EXTENDED RUNS OF THE GLOBAL ENSEMBLE
FORECAST SYSTEM VERSION 12 (GEFSV12) AND THE EUROPEAN CENTRE FOR MEDIUM-RANGE
WEATHER FORECASTS (ECMWF) MODELS. A LA NIñA ADVISORY IS STILL IN EFFECT. THE
LATEST WEEKLY SEA SURFACE TEMPERATURE (SST) DEPARTURES REACHED -0.5 DEGREES
CELSIUS IN THE NIñO 4 REGION AND -0.3 DEGREES CELSIUS IN THE NIñO 3 REGION OVER
THE LAST WEEK. THIS IS A WEAK LA NIñA EVENT, SO WHILE WE MAY EXPECT SOME OF THE
TYPICAL IMPACTS, WE ALSO EXPECT GREATER VARIABILITY IN TEMPERATURE AND
PRECIPITATION DURING THE MONTH OR SEASON. THE MJO HAS BEGUN TO WEAKEN AND STALL
IN PHASE 8, RETREATING BACK INTO THE UNIT CIRCLE, DUE TO DESTRUCTIVE
INTERFERENCE WITH EQUATORIAL ROSSBY WAVE ACTIVITY AND THE LOW-FREQUENCY BASE
STATE, HOWEVER, DYNAMICAL MODEL FORECASTS OF THE REALTIME MULTIVARIATE MJO
(RMM) INDEX FAVOR THE RETURN OF EASTWARD PROPAGATION OF THE SIGNAL, BUT THIS IS
ALSO WEAK AND THERE IS UNCERTAINTY IN MODELS ON THE STRENGTH OF THE MJO, WITH
GEFS FAVORING A STRONGER MJO AND ECWMF KEEPING THE MJO RATHER WEAK. GIVEN THE
WEAKNESS OF THESE DRIVERS AS WELL AS THE VARIABILITY SEEN IN SHORTER TERM
FORECASTS, WE EXPECT A FAIRLY TRANSIENT PATTERN THROUGH AT LEAST THE FIRST HALF
OF MARCH.
IN THE NEAR-TERM FORECAST PERIOD (I.E. THE 6-10 DAY AND 8-14 DAY FORECASTS
THROUGH ABOUT MID-MARCH), AN ACTIVE, TRANSIENT PATTERN IS EXPECTED WHICH WOULD
BRING VARIABLE WEATHER TO THE CONTIGUOUS UNITED STATES (CONUS). IN THE 6-10 DAY
PERIOD, THE MEAN MID-LEVEL HEIGHT PATTERN FAVORS BELOW NORMAL HEIGHTS ACROSS
MUCH OF THE EASTERN CONUS TO THE PACIFIC NORTHWEST, WITH NEAR NORMAL HEIGHTS
FAVORED OVER THE WEST AND CENTRAL CONUS. AN ACTIVE SOUTHERN STREAM AND
ASSOCIATED SHORTWAVE TROUGHING ADD TO THE TRANSIENT FORECAST FOR EARLY MARCH.
THE PATTERN IS LESS PROGRESSIVE INTO THE WEEK-2 PERIOD, BUT STILL ACTIVE AND
COMPLEX. THIS TRANSIENT PATTERN IN THE FIRST HALF OF MARCH ADDS SOME
UNCERTAINTY TO THE MONTHLY FORECAST. IN THE WEEKS 3-4 PERIOD (THROUGH
APPROXIMATELY THE END OF MARCH), MODELS FAVOR MID-LEVEL TROUGHING OVER ALASKA
AND THE NORTHWEST, AND WEAK RIDGING OVER THE SOUTH AND EAST WITH THE RIDGE AXIS
FAVORED TO BE OFF THE EAST COAST. OVERALL, THE MARCH FORECAST IS COMPLEX AND
VARIABILITY IS EXPECTED, PARTICULARLY IN THE FIRST HALF OF THE MONTH.
THE UPDATED MARCH 2025 TEMPERATURE OUTLOOK FEATURES BELOW NORMAL TEMPERATURES
OVER THE NORTHWEST AND APPROXIMATELY THE NORTHERN HALF OF CALIFORNIA, AND THE
SOUTHERN TWO-THIRDS OF ALASKA. ABOVE NORMAL TEMPERATURES ARE FAVORED OVER THE
NORTHERN PLAINS, CENTRAL CONUS, AND SOUTHERN U.S. INCLUDING THE GULF STATES AND
PARTS OF THE SOUTHERN MID-ATLANTIC. TROUGHING IS EXPECTED THROUGHOUT MUCH OF
THE MONTH OVER THE WEST, LEADING TO THE FAVORED BELOW NORMAL TEMPERATURES OVER
PARTS OF THE WEST COAST. THE AREA OF BELOW NORMAL TEMPERATURES IS ADDITIONALLY
SUPPORTED BY THE TYPICAL LA NIñA TELECONNECTION, EVEN THOUGH THE LA NIñA IS
WEAK. FORECASTS FOR ABOVE NORMAL TEMPERATURES HAVE ALSO BEEN FAIRLY CONSISTENT
OVER THE NORTH-CENTRAL, CENTRAL, AND SOUTHERN CONUS, WHICH LEADS TO RELATIVELY
ENHANCED PROBABILITIES OVER THESE REGIONS. A SIGNIFICANT SWING IN THE PATTERN
AND TEMPERATURES IS EXPECTED EARLY IN MARCH OVER ALASKA, WHERE SHORTER TERM
FORECASTS FAVOR A RAPID SWAP FROM ABOVE NORMAL TEMPERATURES TO BELOW NORMAL
TEMPERATURES AS TROUGHING MOVES INTO THE REGION, WHICH THEN REMAINS CONSISTENT
INTO THE WEEKS 3-4 PERIOD. AS THE ABOVE NORMAL TEMPERATURES APPEAR TO BE
SHORTER LIVED OVER ALASKA, THE OVERALL MARCH FORECAST HAS A TILT TOWARD BELOW
NORMAL. SWINGS IN TEMPERATURES ARE ALSO EXPECTED IN THE SHORT TERM (EARLY
MARCH) OVER THE EAST, WITH PERIODS OF BELOW NORMAL TEMPERATURES POSSIBLE,
PARTICULARLY FOR THE NORTHEAST. THIS GIVES WAY TO RIDGING AND ABOVE NORMAL
TEMPERATURES BY THE MIDDLE TO END OF MARCH. DESPITE THE VARIABILITY IN EARLY
MARCH, MUCH OF THE SOUTHERN HALF OF THE EAST COAST IS FAVORED TO BE ABOVE
NORMAL GIVEN THE FORECASTS FOR THE MID TO END OF MARCH GIVEN WEAKER SIGNALS FOR
BELOW NORMAL TEMPERATURES, WHILE EQUAL CHANCES (EC) OF ABOVE, NEAR, AND BELOW
NORMAL TEMPERATURES ARE FAVORED FOR THE NORTHEAST WHERE SOME PERIODS OF BELOW
NORMAL TEMPERATURES ARE MORE STRONGLY FORECASTED.
IN CONTRAST TO TEMPERATURES, MODEL FORECASTS HAVE BEEN MORE CONSISTENT ON THE
PRECIPITATION SIGNALS. MID-LEVEL TROUGHING AND ONSHORE FLOW SUPPORTS ENHANCED
PROBABILITIES OF ABOVE NORMAL PRECIPITATION OVER PARTS OF CALIFORNIA AND THE
NORTHWEST, THOUGH THERE IS SOME UNCERTAINTY ON HOW FAR SOUTH THE ABOVE NORMAL
PRECIPITATION WILL REACH GIVEN DYNAMICAL MODELS AND THE LA NIñA TELECONNECTION
THAT SUPPORT BELOW NORMAL PRECIPITATION OVER SOUTHERN CALIFORNIA. THUS, EC OF
ABOVE, NEAR, AND BELOW NORMAL PRECIPITATION ARE APPROPRIATE OVER SOUTHERN
CALIFORNIA, DESPITE THE EARLY MARCH ABOVE NORMAL PRECIPITATION SIGNAL THAT
COVERS MUCH OF THE STATE. ABOVE NORMAL PRECIPITATION IS ALSO FAVORED OVER THE
GREAT LAKES AND PARTS OF NORTHERN NEW ENGLAND, AS SUPPORTED BY DYNAMICAL
MODELS, AND THE LA NIñA TELECONNECTION. MOST DYNAMICAL MODELS FAVOR ABOVE
NORMAL PRECIPITATION OVER ALASKA AND IT IS THE CLIMATOLOGICALLY DRIEST TIME OF
YEAR FOR PRECIPITATION, AS SUCH A TILT TOWARD ABOVE NORMAL IS INDICATED OVER
MUCH OF THE STATE. BELOW NORMAL PRECIPITATION IS FAVORED OVER THE SOUTHWEST AND
SOUTHERN PLAINS GIVEN MODEL CONSISTENCY, THOUGH MOST MODELS ALSO TILT TOWARD
BELOW NORMAL OVER THE GULF COAST AND FLORIDA CONSISTENT WITH WHAT WE MIGHT
EXPECT FROM LA NIñA. HOWEVER, THERE IS A CHANCE FOR ABOVE NORMAL PRECIPITATION
OVER THE GULF STATES IN THE SHORT TERM, SO EC IS FAVORED. EC IS ALSO FAVORED
OVER THE NORTHERN PLAINS GIVEN WEAK AND INCONSISTENT SIGNALS AMONG MODELS AND
TOOLS.
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***** PREVIOUS MID-MONTH DISCUSSION BELOW *****
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A NUMBER OF EXTRATROPICAL DRIVERS ARE PRESENT THAT MAY IMPACT THE MARCH 2025
TEMPERATURE AND PRECIPITATION PATTERNS OVER THE U.S. LA NIñA CONDITIONS
CONTINUE IN THE EQUATORIAL PACIFIC, AND SEA SURFACE TEMPERATURE (SST) ANOMALIES
WERE -0.3 DEGREES CELSIUS BELOW NORMAL IN THE NIñO3.4 REGION DURING THE PAST
WEEK, AND REACHED -0.7 DEGREES CELSIUS BELOW NORMAL IN THE NIñO4 REGION. LA
NIñA CONDITIONS ARE EXPECTED TO PERSIST IN THE NEAR TERM BEFORE TRANSITIONING
TO EL NIñO SOUTHERN OSCILLATION (ENSO) NEUTRAL DURING THE SPRING. IN ADDITION
TO THE POTENTIAL LA NIñA IMPACTS, THE MADDEN JULIAN OSCILLATION (MJO) MAY HAVE
SOME BEARING ON THE FORECAST. THERE HAS BEEN COHERENT MJO ACTIVITY SINCE THE
BEGINNING OF 2025, AND THOUGH DYNAMICAL MODEL FORECASTS OF THE REALTIME
MULTIVARIATE MJO (RMM) INDEX FOR THE SHORT TERM FAVOR A SLOWED AND ERRATIC
EVOLUTION OF THE MJO SIGNAL DUE TO A STRONG EQUATORIAL ROSSBY WAVE, EASTWARD
PROPAGATION IS FORECAST TO RESUME NEAR THE BEGINNING OF MARCH. FINALLY, THE
ARCTIC OSCILLATION (AO) IS FORECAST TO BECOME POSITIVE IN THE LAST WEEK OF
FEBRUARY, THOUGH THIS IS FOLLOWED BY FORECASTS OF A SHARP DROP TO NEAR NEUTRAL
TO START THE MONTH OF MARCH, WHICH MAY LEAD TO A MORE TRANSIENT PATTERN TO
START THE MONTH. THOUGH WE EXPECT SOME LINGERING IMPACTS OF THE LA NIñA THROUGH
THE MONTH OF MARCH, THESE OTHER NOTED INFLUENCES ARE ALSO CONSIDERED FOR THE
MARCH 2025 TEMPERATURE AND PRECIPITATION OUTLOOKS, WHICH MAY MODIFY THE
CANONICAL LA NIñA PATTERN.
SHORT TERM OUTLOOKS THROUGH THE END OF FEBRUARY DEPICT A PROGRESSIVE FLOW
PATTERN. IN THE MEAN, THE MID-LEVEL FLOW PATTERN FAVORS RIDGING OVER THE WEST
AND NEUTRAL TO BELOW NORMAL 500 HPA HEIGHTS OVER THE EAST, WHICH LEADS TO A
WARM END TO FEBRUARY OVER THE WESTERN HALF OF THE CONTIGUOUS UNITED STATES
(CONUS). HOWEVER, THE MID-LEVEL HEIGHT PATTERN IS EXPECTED TO BE PROGRESSIVE AS
WE END THE MONTH OF FEBRUARY AND MOVE INTO EARLY MARCH. AS MARCH BEGINS, THE
MID-LEVEL HEIGHT PATTERN IS FORECAST TO WEAKEN AND RETROGRADE, LEADING TO
VARIABLE HEIGHTS OVER THE EAST AND BELOW NORMAL HEIGHTS ERODING AWAY THE
RIDGING OVER THE WESTERN HALF OF THE CONUS. THIS APPEARS TO CONTINUE INTO THE
WEEKS 3-4 PERIOD (THROUGH MID-MARCH), AND MODELS FORECAST TROUGHING OVER THE
NORTHERN PART OF THE CONUS AND ALASKA, AND RIDGING OVER THE SOUTH. HOWEVER,
THERE IS CONSIDERABLE UNCERTAINTY OF THE EXTENT OF TROUGHING INTO THE LOWER 48
WITH SOME MODELS CONTAINING THE BELOW NORMAL HEIGHTS MORE TO THE NORTH OVER
CANADA, AND OTHERS DEPICTING IT REACHING FURTHER SOUTH. THIS LEADS TO
UNCERTAINTY OVER THE NORTHERN THIRD OF THE CONUS PARTICULARLY FOR TEMPERATURE.
THE MARCH 2025 TEMPERATURE OUTLOOK FAVORS BELOW NORMAL TEMPERATURES OVER
SOUTHEASTERN ALASKA AND THE NORTHWEST. ABOVE NORMAL TEMPERATURES ARE INDICATED
OVER NORTHERN ALASKA AND FROM THE SOUTHWEST TO THE SOUTHEAST. THIS SOMEWHAT
RESEMBLES A TYPICAL LA NIñA TELECONNECTION PATTERN FOR MARCH, WHICH WOULD BRING
BELOW NORMAL TEMPERATURES TO SOUTHERN ALASKA AND THE NORTHERN TIER OF THE CONUS
AND ABOVE NORMAL TEMPERATURES TO THE SOUTH, AS WELL AS MONTHLY CFSV2 FORECASTS
OF TEMPERATURES. MULTI-MODEL ENSEMBLE FORECASTS OF MONTHLY TEMPERATURES, SUCH
AS THE NORTH AMERICAN MULTI-MODEL ENSEMBLE (NMME) AND COPERNICUS CLIMATE SUITE
(C3S), SUPPORT THE BELOW NORMAL TEMPERATURES OVER SOUTHEASTERN ALASKA AND THE
NORTHWEST, BUT TILT TOWARD ABOVE NORMAL TEMPERATURE PROBABILITIES OVER THE
EASTERN TWO-THIRDS OF THE CONUS, INCLUDING THE NORTHERN PLAINS AND NEW ENGLAND.
HOWEVER, GIVEN THE PROGRESSIVE BUT BELOW NORMAL 500 HPA HEIGHT PATTERN EXPECTED
IN THE BEGINNING OF MARCH AND DIFFERENCES IN THE SOUTHWARD EXTENT OF THE
MID-LEVEL HEIGHT PATTERN IN WEEK 3-4 MODELS, EQUAL CHANCES (EC) OF ABOVE, NEAR,
AND BELOW NORMAL TEMPERATURES ARE FAVORED FOR THE CENTRAL AND NORTHERN PLAINS
TO THE NORTHERN HALF OF THE EAST COAST WHERE THERE IS HIGHER UNCERTAINTY AND
MODELS DIFFERED. PROBABILITIES OF BELOW NORMAL TEMPERATURES ARE ENHANCED WHERE
THE IMPACT OF LA NIñA, COOLER TEMPERATURES POSSIBLE FROM MJO, AND WHERE THE
TROUGH THAT IS EXPECTED TO RETROGRADE IN EARLY MARCH ARE EXPECTED TO LEAD TO
BELOW NORMAL TEMPERATURES. IN CONTRAST, ABOVE NORMAL TEMPERATURES ARE INDICATED
OVER MUCH OF THE SOUTHERN TIER, AND ARE (RELATIVELY) STRONGER. MODELS AND TOOLS
SUPPORT THE PROBABILITIES OF ABOVE NORMAL TEMPERATURES ALONG THE SOUTH, AS DOES
THE TYPICAL LA NIñA TELECONNECTION AND MID-LEVEL RIDGING THAT IS COMPARATIVELY
MORE STATIONARY.
TOOLS WERE COMPARATIVELY MORE CONSISTENT WHEN CONSIDERING THE PRECIPITATION
PATTERN OVER THE U.S. FOR MARCH. AS HAS BEEN FAIRLY COMMON THE LAST FEW MONTHS,
MODELS TEND TOWARD A LA NIñA LIKE PATTERN FOR PRECIPITATION, WHICH IS FOUND IN
MOST MODELS. THIS IS VERY APPARENT IN NMME AND C3S, WHICH BROADLY FAVOR WEAK
ABOVE NORMAL PRECIPITATION OVER CENTRAL AND NORTHERN ALASKA, THE NORTHWEST, AND
GREAT LAKES TO THE NORTHERN PARTS OF GULF STATES, AND BELOW NORMAL
PRECIPITATION OVER THE SOUTH COAST OF ALASKA, THE SOUTHWEST, SOUTHERN GREAT
PLAINS, AND WESTERN GULF COAST. THE MARCH PRECIPITATION OUTLOOK ALSO BROADLY
FAVORS THIS PATTERN, INDICATING ABOVE NORMAL PRECIPITATION OVER MUCH OF
MAINLAND ALASKA, THE NORTHWEST AND GREAT LAKES TO SOUTHEAST AND BELOW NORMAL
PRECIPITATION OVER THE SOUTHWEST AND SOUTHERN PLAINS, BUT THERE ARE SOME
DIFFERENCES GIVEN EXPECTED INTRA-MONTH VARIABILITY. IN PARTICULAR, EQUAL
CHANCES OF ABOVE, NEAR, AND BELOW NORMAL PRECIPITATION ARE FAVORED OVER THE
SOUTH COAST OF ALASKA GIVEN SHORT TERM FORECASTS FOR ABOVE NORMAL PRECIPITATION
THAT MAY OUTWEIGH THE BELOW NORMAL SIGNAL. SIMILAR ARGUMENTS ARE IN PLACE FOR
THE GULF COAST, WHICH IS TYPICALLY BELOW NORMAL DURING LA NIñA, BUT IS
APPEARING TO BE MORE VARIABLE IN THE SHORTER TERM FORECASTS, THUS EC IS FAVORED
FOR THE EASTERN GULF COAST. EC IS ALSO FAVORED OVER THE NORTHERN PLAINS,
DESPITE SOME MODELS SUCH AS CFSV2 INDICATING WEAK CHANCES OF ABOVE NORMAL
PRECIPITATION, DUE TO UNCERTAINTY IN REMAINING TOOLS AND RELATIVELY STRONGER
SIGNALS OVER THE NORTHWEST AND GREAT LAKES.
FORECASTER: JOHNNA INFANTI
THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1991 AND 2020, FOLLOWING
THE WORLD METEOROLOGICAL ORGANIZATION CONVENTION OF USING THE MOST RECENT 3
COMPLETE DECADES AS THE CLIMATE REFERENCE PERIOD. THE PROBABILITY ANOMALIES
FOR TEMPERATURE AND PRECIPITATION BASED ON THESE NEW NORMALS BETTER REPRESENT
SHORTER TERM CLIMATIC ANOMALIES THAN THE FORECASTS BASED ON OLDER NORMALS.
THE NEXT MONTHLY OUTLOOK...FOR APR ... WILL BE ISSUED ON THU MAR 20 2025
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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