Skip Navigation Links www.nws.noaa.gov 
NOAA logo - Click to go to the NOAA home page National Weather Service   NWS logo - Click to go to the NWS home page
Climate Prediction Center
 
 

CPC Search
About Us
   Our Mission
   Who We Are

Contact Us
   CPC Information
   CPC Web Team

Official 90-day Outlooks are issued once each month near mid-month at 8:30am Eastern Time. Please consult the schedule of 30 & 90-day outlooks for exact release dates.

Text Discussions
   90day Prognostic
   30day Prognostic
   Hawaiian
   Tools


More Outlooks
    0.5mn SON 2016
    1.5mn OND 2016
    2.5mn NDJ 2016
    3.5mn DJF 2016
    4.5mn JFM 2017
    5.5mn FMA 2017
    6.5mn MAM 2017
    7.5mn AMJ 2017
    8.5mn MJJ 2017
    9.5mn JJA 2017
   10.5mn JAS 2017
   11.5mn ASO 2017
   12.5mn SON 2017
    0.5mn Sep 2016


Tools Used (see Discussion for explanation)
   CCA
   OCN
   CMP
   SMT
   POE
 
HOME> Outlook Maps>Seasonal Forecast Discussion
 
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK 
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT WED AUG 31 2016

30-DAY OUTLOOK DISCUSSION FOR SEPTEMBER 2016

THE UPDATES TO THE OUTLOOKS FOR TEMPERATURE AND PRECIPITATION FOR SEPTEMBER
2016 ARE BASED ON RECENT DYNAMICAL GUIDANCE, AS WELL AS THE LATEST OFFICIAL
OUTLOOKS FROM CPC, WPC, AND NHC. SIGNIFICANT UNCERTAINTY EXISTS NOT ONLY TOWARD
THE END OF THE OUTLOOK PERIOD (WEEKS 3 AND 4), BUT ALSO IN THE SHORT-TERM DUE
TO THE IMPACT OF TROPICAL CYCLONE ACTIVITY NEAR AND OVER THE EASTERN CONUS.

RECENT OUTPUTS FROM DYNAMICAL MODELS SUGGEST A WARM FIRST HALF OF THE MONTH FOR
SEPTEMBER, WITH THE HIGHEST ODDS OVER THE NORTHEAST. DUE TO THE PROJECTED PATH
OF THE TROPICAL CYCLONE CURRENTLY OVER THE GULF OF MEXICO, UNCERTAINTY IS
ELEVATED OVER THE NORTHEAST, OTHERWISE THE ODDS FOR ABOVE NORMAL TEMPERATURES
WOULD BE HIGHER. WEST OF THE PATH OF THE RAINS ASSOCIATED WITH THE TROPICAL
CYCLONE, DRY CONDITIONS SHOULD CONTRIBUTE TO ABOVE NORMAL TEMPERATURES OVER THE
INTERIOR SOUTHEAST. THROUGH WEEK-2, GUIDANCE SUGGESTS ENHANCED ODDS FOR BELOW
NORMAL TEMPERATURES OVER THE NORTHERN ROCKIES, SO ENHANCED ODDS OF ABOVE NORMAL
TEMPERATURES ON THE MONTHLY MAP HAVE BEEN REMOVED FROM THAT REGION. RECENT
REDUCTION IN SSTS NEAR NORTHERN ALASKA REDUCE THE ODDS FOR ABOVE NORMAL
TEMPERATURES FOR THE NORTHERN SLOPE, WHILE SSTS WELL ABOVE NORMAL NEAR
SOUTHWESTERN ALASKA STILL FAVOR ABOVE NORMAL TEMPERATURES THERE.

MODEL FORECASTS AND OFFICIAL FORECASTS FROM NHC INDICATE THE GREATEST IMPACTS
FROM TROPICAL ACTIVITY ARE LIKELY FROM FLORIDA TO THE NORTHEAST, THEREFORE ODDS
FOR ABOVE MEDIAN PRECIPITATION ARE ENHANCED FOR THAT REGION. THE AREA WHERE
BELOW MEDIAN PRECIPITATION IS FAVORED OVER THE INTERIOR SOUTHEAST AT THE
MID-MONTH OUTLOOK IS SHIFTED NORTHWESTWARD. MODEL GUIDANCE AND OFFICIAL
OUTLOOKS IN THE SHORT TERM AND THROUGH WEEK-2 INDICATE ENHANCED ODDS FOR HEAVY
PRECIPITATION OVER THE NORTHERN GREAT PLAINS AND MIDWEST, SO THAT AREA WAS
ADDED TO THE OUTLOOK. SHORT-TERM GUIDANCE FAVORS SOME MODERATE PRECIPITATION
OVER THE PACIFIC NORTHWEST, INCREASING UNCERTAINTY ABOUT MONTHLY TOTALS, SO THE
AREA OF BELOW MEDIAN PRECIPITATION WAS TRIMMED OUT OF MOST OF WASHINGTON.

----------- PREVIOUS MESSAGE FROM AUGUST 18 IS BELOW ------------

THE SEPTEMBER 2016 TEMPERATURE AND PRECIPITATION OUTLOOKS ARE BASED ON
DYNAMICAL MODEL GUIDANCE AND, TO A LESSER EXTENT, STATISTICAL TOOLS. THE IMPACT
OF CURRENT SOIL MOISTURE CONDITIONS ON THE TEMPERATURES DURING THE FOLLOWING
MONTH BEGINS TO WANE IN THE AUTUMN, BUT THERE IS STILL A RESPECTABLE
CORRELATION OVER THE SOUTHERN GREAT PLAINS BETWEEN AUGUST SOIL MOISTURE AND
SEPTEMBER TEMPERATURES.  ENSO IS NOW IN ITS NEUTRAL PHASE ACROSS THE TROPICAL
PACIFIC. LA NINA IS SLIGHTLY FAVORED TO DEVELOP DURING AUGUST - OCTOBER 2016,
WITH ABOUT A 55-60% CHANCE OF LA NINA DURING THE FALL AND WINTER 2016-17.
PLEASE REFER TO THE ENSO DIAGNOSTIC DISCUSSION AT:
HTTP://WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/ANALYSIS_MONITORING/ENSO_ADVISORY/ FOR A
MORE DETAILED ANALYSIS OF ENSO CONDITIONS ACROSS THE EQUATORIAL PACIFIC.

DURING THE FIRST HALF OF AUGUST, ABOVE AVERAGE CONVECTION HAS DEVELOPED OVER
THE WESTERN PACIFIC, WITH MULTIPLE TROPICAL CYCLONES FORMING. MOST MJO INDICES
HAVE AMPLIFIED IN A DIRECTION INDICATING ENHANCED CONVECTION OVER THE WESTERN
PACIFIC. GOING FORWARD, MOST MODELS CONTINUE TO INDICATE CONVECTION OVER THE
WESTERN PACIFIC, WHICH COULD HAVE A DOWNSTREAM IMPACT ON THE CIRCULATION OVER
NORTH AMERICA, ALTHOUGH THAT CONNECTION IS MORE ROBUST LATER IN THE MONTH
BECAUSE OF THE DYNAMICS OF THE SEASONAL PROGRESSION OF THE EAST ASIAN JET
STREAM. DYNAMICAL MODELS ARE LIKELY THE BEST TOOLS TO CAPTURE THIS POTENTIAL
IMPACT. THEREFORE, THE OUTLOOKS RELY PRIMARILY UPON THE LATEST DYNAMICAL MODEL
GUIDANCE FROM THE NCEP CLIMATE FORECAST SYSTEM (CFS), THE NORTH AMERICAN
MULTI-MODEL ENSEMBLE (NMME), THE INTERNATIONAL MULTI-MODEL ENSEMBLE (IMME), AND
MODEL GUIDANCE FOR WEEKS 3 AND 4 FROM THE CFS, JAPAN METEOROLOGICAL AGENCY
(JMA), AND ECMWF, WITH LESSER INPUTS FROM TOOLS BASED ON CURRENT SOIL MOISTURE
CONDITIONS.

MOST DYNAMICAL MODELS FROM THE NMME SUITE INDICATE GENERALLY ABOVE AVERAGE
TEMPERATURES FOR SEPTEMBER 2016. ANY AREAS WHERE NEAR OR BELOW AVERAGE
CONDITIONS ARE INDICATED ARE OVER THE CENTRAL PORTIONS OF THE CONUS. CURRENTLY
HIGH SOIL MOISTURE OVER THE SOUTHERN GREAT PLAINS WOULD FAVOR NEAR TO BELOW
AVERAGE TEMPERATURES OVER THAT REGION, WHILE UNCERTAINTY AMONG THE MODELS (NMME
AND IMME) PROHIBITS THE DEPICTION OF A SIGNAL FROM THE NORTHERN GREAT PLAINS TO
THE GREAT LAKES REGION. MORE AGREEMENT RETURNS OVER THE NORTHEAST, WHERE TOOLS
INDICATE ABOVE AVERAGE TEMPERATURES ARE FAVORED, AND OVER THE WESTERN CONUS
FROM THE ROCKIES TO THE WEST COAST, WHERE MODELS AND TRENDS FAVOR ABOVE AVERAGE
TEMPERATURES. SSTS 1.5-3.5 DEGREES C ABOVE AVERAGE IN THE VICINITY OF ALASKA
FAVOR ABOVE AVERAGE TEMPERATURES FOR SOUTHERN AND WESTERN ALASKA, WHILE TRENDS
FAVOR ABOVE AVERAGE TEMPERATURES FOR THE NORTH SLOPE.

THE PRECIPITATION OUTLOOK FOR SEPTEMBER CONTAINS A HIGH AMOUNT OF UNCERTAINTY.
MODEL SIGNALS ARE SPARSE IN COVERAGE, AND WEAK EVEN WHERE SIGNALS PASS THROUGH
THE CALIBRATION METHODS. TRENDS FAVOR BELOW AVERAGE PRECIPITATION OVER THE
SOUTHWEST WHILE MOST MODELS IN THE NMME SUITE FAVOR ABOVE AVERAGE
PRECIPITATION. THE OFFICIAL OUTLOOK FAVORS ABOVE AVERAGE PRECIPITATION, BUT
OVER A SMALLER AREA THAN WHAT THE DYNAMICAL MODELS INDICATE TO ACCOUNT FOR THE
UNCERTAINTY RAISED BY CONFLICTING GUIDANCE. OVER THE NORTHERN GREAT PLAINS,
ABOUT HALF OF THE MODELS DEPICT ABOVE AVERAGE PRECIPITATION AND TRENDS FROM THE
SEASONAL OPTIMAL CLIMATE NORMALS HAVE LITTLE TO NO SIGNAL, SO NO SIGNAL IS
DEPICTED. TRENDS AND MODELS DEPICT BELOW AVERAGE PRECIPITATION FOR THE
NORTHWEST AND FROM THE SOUTHERN GREAT PLAINS TO THE SOUTHEAST. MODEL FORECASTS
SUPPORT ABOVE AVERAGE PRECIPITATION FOR SOUTHERN ALASKA, ALTHOUGH THEY VARY IN
WHERE THE HIGHEST AMOUNTS ARE LIKELY TO OCCUR, SO THE OFFICIAL FORECAST COVERS
ALL OF THE AREAS WHERE THE NMME MODELS FAVOR ABOVE AVERAGE PRECIPITATION.


FORECASTER: MATTHEW ROSENCRANS


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 OCT ... WILL BE ISSUED ON THU SEP 15 2016


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

$$

NOAA/ National Weather Service
National Centers for Environmental Prediction
Climate Prediction Center
5200 Auth Road
Camp Springs, Maryland 20746
Climate Prediction Center Web Team
Page last modified: January 17, 2006
Disclaimer
Information Quality
Credits
Glossary
Privacy Policy
Freedom of Information Act
About Us
Career Opportunities