PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EST TUE FEB 28 2017

30-DAY OUTLOOK DISCUSSION FOR MARCH 2017

THE UPDATED MARCH OUTLOOK UTILIZES INFORMATION ACROSS TIME SCALES IN ADJUSTING 
THE PREVIOUS MID-MONTH OUTLOOK. THE UPDATED OUTLOOK IS MODIFIED PRIMARILY BASED 
ON SHORT-, MEDIUM- AND EXTENDED-RANGE DYNAMICAL MODEL GUIDANCE, MJO 
CONSIDERATIONS, AND TO A LESSER DEGREE WEEK 3-4 MODEL GUIDANCE.

A MAJOR PLAYER EARLY IN THE PERIOD IS THE BLOCK SITUATED WEST OF ALASKA WHICH 
FAVORS DOWNSTREAM TROUGHING ACROSS MAINLAND ALASKA INTO THE GULF OF ALASKA 
LIKELY RESULTING IN STRONG ONSHORE FLOW INTO THE PACIFIC NORTHWEST. POSITIVE 
500-HPA HEIGHT DEPARTURES ARE EXPECTED TO BE PREVALENT ACROSS MUCH OF THE 
WESTERN AND CENTRAL CONUS AS WE APPROACH THE MEDIUM AND EXTENDED RANGES, WHILE 
ACROSS THE EASTERN CONUS, THERE IS CONSIDERABLE VARIABILITY AND UNCERTAINTY FOR 
THE DEGREE OF TROUGHING, AND SO INTRUSIONS OF COLDER AIR MASSES INTO THIS 
REGION.  

THE MJO REMAINS ACTIVE AND IS CURRENTLY CENTERED ACROSS THE WEST-CENTRAL INDIAN 
OCEAN AND IS EXPECTED TO MAINTAIN AT LEAST MODEST ORGANIZATION ENTERING MARCH, 
ALTHOUGH CANONICAL TELECONNECTIONS TO THE MID-LATITUDES OFTEN ASSOCIATED WITH 
THE MJO HAVE BEEN LIMITED THIS WINTER TO DATE. 

THE PREVIOUS TEMPERATURE OUTLOOK IS ADJUSTED IN THE UPDATE IN THE FOLLOWING 
WAY.    STRONG ANOMALOUS NORTHERLY FLOW DOWNSTREAM OF HIGH LATITUDE BLOCKING 
RESULTS IN FAVORED BELOW NORMAL TEMPERATURES AT RATHER HIGH PROBABILITIES FOR 
THE STATE OF ALASKA, A CHANGE FROM THE HALF MONTH LEAD OUTLOOK. MOREOVER, THE 
TROUGHING FAVORS A WESTWARD SHIFT OF FAVORED BELOW NORMAL TEMPERATURES FROM THE 
ORIGINAL OUTLOOK FROM THE NORTHERN ROCKIES TO A RELATIVELY SMALL REGION OF THE 
PACIFIC NORTHWEST WHICH IS INDICATED BY MEDIUM- AND EXTENDED-RANGE MODEL 
GUIDANCE. MONTHLY FORECASTS OF THE CFS ALSO INDICATE THE LATTER AREA, BUT THE 
MAGNITUDE AND SPATIAL COVERAGE APPEAR TO BE OVERDONE. 

COVERAGE AND PROBABILITIES OF ABOVE NORMAL TEMPERATURES ARE INCREASED IN THE 
UPDATE FROM THE HALF MONTH LEAD OUTLOOK. MODEL GUIDANCE ACROSS TIME SCALES 
SUPPORTS THIS CHANGE WITH THE GREATEST PROBABILITIES SITUATED ACROSS THE SOUTH 
CENTRAL PLAINS. MJO ACTIVITY ENTERING MARCH WOULD ALSO FAVOR A WARMER SOLUTION 
IN TIME FOR PARTS OF THE CENTRAL AND EASTERN CONUS.

FOR PRECIPITATION, THE NEED FOR SOME CHANGES FROM THE ORIGINAL OUTLOOK WAS ALSO 
REQUIRED. THE AMPLIFIED 500-HPA HEIGHT PATTERN IN PROXIMITY TO ALASKA NOW 
FAVORS  BELOW MEDIAN PRECIPITATION FOR MUCH OF THE STATE. MOREOVER, EARLY IN 
THE PERIOD INTO THE EXTENDED RANGE THE PREDICTED FLOW IMPINGING ON THE PACIFIC 
NORTHWEST AND LIKELY AN ENHANCED STORM TRACK ACROSS THE NORTHERN TIER OF THE 
CONUS SHIFTS THE GREATEST LIKELIHOOD FOR ABOVE MEDIAN PRECIPITATION FOR MARCH 
FROM THE NORTHERN ROCKIES TO THE PACIFIC NORTHWEST, AND THIS AREA IS EXPANDED 
ALONG THE EXTREME NORTHERN TIER OF THE CONUS TO THE GREAT LAKES. 

THE AREA OF BELOW MEDIAN PRECIPITATION IN THE SOUTHWEST CONUS IN THE ORIGINAL 
OUTLOOK IS EXPANDED TO STRETCH FROM CALIFORNIA TO THE CENTRAL PLAINS CONSISTENT 
WITH SHORT-, MEDIUM- AND EXTENDED-RANGE MODEL GUIDANCE AND INTEGRATED MONTHLY 
FORECASTS FROM THE CFS. EQUAL CHANCES IS FORECAST FOR PARTS OF THE OHIO VALLEY, 
TENNESSEE VALLEY AND SOUTHEAST, AS SOMEWHAT COMPETING SIGNALS OVER THE COURSE 
OF THE MONTH LOWERED CONFIDENCE FOR MONTHLY PRECIPITATION TOTALS AS A WHOLE IN 
SOME OF THESE AREAS.     

**** PREVIOUS DISCUSSION FROM MID-MONTH OUTLOOK IS BELOW ****

AN INITIAL REVIEW OF SOME OF THE FACTORS TYPICALLY CONSIDERED IN FORMULATING 
THE HALF MONTH LEAD MONTHLY OUTLOOK INCLUDE CONDITIONS ACROSS THE TROPICS. 
OCEANIC AND MOST ATMOSPHERIC INDICATORS ASSOCIATED WITH LA NINA CONDITIONS HAVE 
FADED AND CPC ISSUED ITS FINAL LA NINA ADVISORY EARLIER THIS MONTH. LA NINA WAS 
NOT CONSIDERED IN THE MARCH 2017 TEMPERATURE AND PRECIPITATION OUTLOOK. AT THE 
SUBSEASONAL TIME SCALE, WE DO HOWEVER, OBSERVE A ROBUST MJO EVENT WITH THE 
ENHANCED CONVECTIVE PHASE CENTERED ACROSS THE WESTERN HEMISPHERE AND THE 
SUPPRESSED CONVECTIVE PHASE LOCATED ACROSS THE INDIAN OCEAN AND MARITIME 
CONTINENT REGION AND THIS SIGNAL WAS CONSIDERED IN DEVELOPING THE MARCH 
OUTLOOK. ANOMALOUS SNOW COVER AND ABOVE NORMAL COASTAL SEA SURFACE TEMPERATURES 
IN SOME AREAS WERE ALSO CONSIDERED.

INFORMATION FROM DYNAMICAL MODEL GUIDANCE PLAYED A LARGE ROLE AS WELL IN THE 
INITIAL MARCH 2017 OUTLOOK AND INCLUDED WEEK 3-4 MODEL GUIDANCE FROM THE CFS 
AND ECMWF MODEL SYSTEMS AND MONTHLY GUIDANCE AS A WHOLE FROM THE CFS. 
STATISTICAL FORECAST GUIDANCE LINKED TO PREDICTORS SUCH AS THE MJO, ENSO AND 
TREND FOR THE WEEK 3-4 TIME PERIOD ALSO CONTRIBUTED TO THE OUTLOOK.

THE MARCH 2017 TEMPERATURE OUTLOOK DEPICTS A CONSIDERABLE AREA OF EQUAL CHANCES 
(EC) AT THIS HALF MONTH LEAD AS THERE IS CONSIDERABLE UNCERTAINTY IN A NUMBER 
OF THE FORECAST TOOLS. LAGGED 200-HPA HEIGHT AND TEMPERATURE COMPOSITES LINKED 
TO THE CURRENT MJO PHASE WOULD TEND TO FAVOR IN TIME NEGATIVE HEIGHT DEPARTURES 
AND AREAS OF BELOW NORMAL TEMPERATURES FOR CONSIDERABLE PORTIONS OF THE CONUS 
DURING LATER FEBRUARY INTO EARLY MARCH INCLUDING THE EASTERN U.S. THIS IS 
CURRENTLY AT ODDS WITH WEEK-2 GUIDANCE WHICH ON AVERAGE CONTINUES TO FAVOR 
ABOVE-NORMAL TEMPERATURES IN THIS REGION CLOSE TO EARLY MARCH.   

FOR THE INITIAL MARCH 2017 OUTLOOK, BELOW NORMAL TEMPERATURES ARE FAVORED FOR A 
REGION WHERE MJO RELATED INFORMATION (ABOVE DESCRIBED COMPOSITES AND 
STATISTICAL FORECAST TOOLS) AND DYNAMICAL MODEL GUIDANCE FROM BOTH WEEK 3-4 AND 
THE CFS MONTHLY FORECAST ARE CONSISTENT. THIS REGION IS FOR A SMALL AREA THAT 
INCLUDES PORTIONS OF THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS. ABOVE 
NORMAL TEMPERATURES ARE FAVORED ACROSS THE SOUTHERN TIER OF THE CONTIGUOUS U.S. 
WHERE, IN GENERAL, THERE IS AGREEMENT FROM WEEK 3-4 MODEL GUIDANCE FROM THE CFS 
AND ECMWF AND THE CFS MONTHLY FORECAST AS WELL AS SUPPORT FROM LONG TERM 
TRENDS.          ABOVE NORMAL TEMPERATURES ARE FAVORED FOR PORTIONS OF WESTERN 
ALASKA SUPPORTED BY ABOVE NORMAL SEA SURFACE TEMPERATURES IN SOME AREAS AND 
AVAILABLE DYNAMICAL MODEL GUIDANCE. 

THE MARCH 2017 PRECIPITATION OUTLOOK IS STRONGLY BASED ON AVAILABLE DYNAMICAL 
MODEL GUIDANCE AND TO A LESSER DEGREE MJO CONSIDERATIONS. ABOVE MEDIAN 
PRECIPITATION IS FAVORED FOR PORTIONS OF THE SOUTHEAST CONUS IN PART DUE TO MJO 
STATISTICAL FORECAST GUIDANCE AND IS ALSO SUPPORTED BY DYNAMICAL MODEL GUIDANCE 
FROM BOTH THE WEEK 3-4 PERIOD GUIDANCE AS WELL AS THE CFS MONTHLY FORECAST. 
ABOVE MEDIAN PRECIPITATION IS ALSO MOST LIKELY DURING MARCH 2017 FOR AREAS OF 
THE NORTHERN ROCKIES AND NORTHERN HIGH PLAINS WHERE BOTH LONG TERM TRENDS AND 
DYNAMICAL MODEL GUIDANCE DEPICT A POTENTIAL SIGNAL. PRIMARILY BASED ON THE CFS 
MONTHLY FORECAST AND LONG TERM TRENDS, THERE ARE ELEVATED ODDS FOR BELOW-MEDIAN 
PRECIPITATION FOR AREAS STRETCHING FROM ARIZONA TO WEST TEXAS, WHILE 
WEST-CENTRAL ALASKA IS FAVORED TO SEE ABOVE-MEDIAN PRECIPITATION.


FORECASTER: JON GOTTSCHALCK


THE CLIMATIC NORMALS ARE BASED ON CONDITIONS BETWEEN 1981 AND 2010, 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 16 2017


THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1981-2010 BASE PERIOD.

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