Prognostic Meteorological Discussion
Issued by NWS

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1
000
FXUS07 KWBC 311900
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300PM EDT FRIDAY OCT 31 2014

30-DAY OUTLOOK DISCUSSION FOR NOVEMBER 2014

THE UPDATED MONTHLY OUTLOOK FOR NOVEMBER, 2014 REFLECTS BOTH THE INFLUENCE
EXPECTED WEATHER SYSTEMS IN THE FIRST HALF OF THE MONTH TOGETHER WITH THE
CLIMATIC SIGNALS. THE ATMOSPHERIC AND OCEANIC CONDITIONS THAT INFLUENCE THE
CLIMATE REMAINED QUITE SIMILAR TO CONDITIONS IN MID-MONTH FOR MOST ELEMENTS.

ONE EXCEPTION IS THE SEA SURFACE TEMPERATURE ANOMALIES OFF WESTERN ALASKA THAT
HAVE DECREASED SIGNIFICANTLY IN THE TWO WEEKS SINCE THE MID-MONTH OUTLOOK WAS
ISSUED. THIS RESULTS IN LOWER CONFIDENCE FOR ABOVE-NORMAL MONTHLY MEAN AIR
TEMPERATURES FOR WESTERN PARTS OF THE STATE. HOWEVER, PREDICTIONS FROM BOTH THE
GFS AND CFS MODELS CONTINUE TO GENERALLY FAVOR ABOVE-NORMAL TEMPERATURES FOR
MOST OF ALASKA, INCLUDING COASTAL REGIONS.



THE COLD START TO THE MONTH IN THE PARTS OF THE EASTERN CONUS DIMINISHES THE
CONFIDENCE IN THE OUTLOOK FOR ABOVE-NORMAL TEMPERATURES, AND RESULTS IN SOME
DIMINISHED COVERAGE.  THERE CONTINUES TO BE A BROAD CONSENSUS FOR ABOVE-NORMAL
TEMPERATURE AMONG TOOLS IN THE MUCH OF THE NORTHERN AND WESTERN CONUS,
RESULTING IN LITTLE CHANGE FROM THE NOVEMBER OUTLOOK ISSUED AT MID-MONTH
OUTSIDE OF THE EASTERN CONUS.



THE PRECIPITATION OUTLOOK FOR NOVEMBER REMAINS QUITE SIMILAR TO THE OUTLOOK
ISSUED IN MID-OCTOBER. THE AREA OF ANTICIPATED ABOVE-MEDIAN MONTHLY
PRECIPITATION TOTALS IN THE SOUTH-CENTRAL CONUS HAS BEEN ADJUSTED SLIGHTLY ON
THE BASIS OF EXPECTED PRECIPITATION IN THE FIRST TWO WEEKS. CONFIDENCE IS QUITE
HIGH FOR TEXAS DUE TO WET CONDITIONS EXPECTED EARLY IN THE MONTH. THE
ATMOSPHERIC CIRCULATION CONTINUES TO SUPPORT ENHANCED PRECIPITATION FOR PARTS
OF THE WEST COAST IN THE FIRST WEEK OF NOVEMBER, BUT THEN PRECIPITATION CHANCES
DIMINISH IN THE WEEK-TWO PERIOD IN CALIFORNIA. THUS, AN AREA OF ENHANCED
CHANCES FOR MONTHLY PRECIPITATION TOTALS EXCEEDING THE CLIMATOLOGICAL MEDIAN
HAS BEEN ADDED TO PARTS OF THE PACIFIC NORTHWEST AND NORTHERN ROCKIES. THERE
HAS BEEN CONSIDERABLE RUN-TO-RUN VARIABILITY IN RECENT DAYS AMONG THE EXTENDED
RANGE GFS MODEL ENSEMBLES, AS WELL AT CFSV2 ENSEMBLES IN THE PREDICTED
PRECIPITATION AMOUNT FALLING OVER THE UPPER GREAT LAKES.  A NEAR EVEN SPLIT
AMONG ENSEMBLES PREDICTING WET AND DRY CONDITIONS SUGGESTS EQUAL CHANCES FOR
ABOVE- NEAR- OR BELOW-MEDIAN MONTHLY PRECIPITATION AMOUNTS NEAR THE GREAT
LAKES, REVISED FROM THE EARLIER SIGNALS FOR DRY CONDITIONS ISSUED IN
MID-OCTOBER.



THE DISCUSSION RELATING TO LARGER SCALE CLIMATIC CONDITIONS ISSUED IN
MID-OCTOBER IS GIVEN BELOW.



THE ATMOSPHERIC AND OCEANIC CONDITIONS CONTINUE TO INDICATE ENSO NEUTRAL
CONDITIONS AS OF EARLY OCTOBER, 2014. SEA SURFACE TEMPERATURES (SST) ANOMALIES
IN THE NINO 3.4 REGION OF THE PACIFIC ARE CURRENTLY AROUND +0.4 C, WHICH IS
JUST BELOW THE SST ANOMALIES USUALLY ASSOCIATED WITH EL NINO. CONVECTION AND
WIND ANOMALIES NEAR THE EQUATOR OVER THE CENTRAL EQUATORIAL PACIFIC ARE NEAR
LONG TERM AVERAGES, SUPPORTING ENSO NEUTRAL CONDITIONS. ON THE OTHER HAND,
SSTS NEAR THE EQUATOR IN THE EASTERN PACIFIC OCEAN AND ALONG THE SOUTH AMERICAN
COAST CONTINUE TO BE AVERAGE BETWEEN 0.5 AND 1.0 DEGREE ABOVE NORMAL, WITH SOME
LOCALIZED ANOMALIES OF OVER +1.0 C. THESE OBSERVATIONS ARE SUGGESTIVE OF EL
NINO CONDITIONS. BOTH STATISTICAL AND DYNAMICAL MODELS CONTINUE TO CONSISTENTLY
PREDICT THAT SST ANOMALIES IN THE NINO 3.4 REGION WILL INCREASE TO LEVELS
NORMALLY ASSOCIATED WITH WEAK EL NINO EVENTS. THE OBSERVATIONS HAVE LAGGED
BEHIND THE PREDICTIONS OF ABOVE NORMAL NINO 3.4 SSTS FOR THE PAST FEW MONTHS,
SO IN SPITE OF GOOD MODEL CONSENSUS THAT NINO 3.4 SST ANOMALIES WILL INCREASE
TO NEAR +0.9 C IN THE NDJ 2014/15 MEAN, ANTICIPATED CONDITIONS IN THE MONTH OF
NOVEMBER ARE EXPECTED REFLECT AT BEST WEAK EL NINO CONDITIONS. THE SST`S ALONG
THE WEST COAST OF NORTH AMERICA ARE SUBSTANTIALLY ABOVE NORMAL, AND THIS,
TOGETHER WITH THE EXPECTATION OF THE EMERGENCE OF WEAK EL NINO CONDITIONS
DURING THE MONTH OF NOVEMBER, MAY INCREASE CHANCES OF EL NINO-LIKE ANOMALY
PATTERNS IN THE TEMPERATURE AND PRECIPITATION OVER THE CONUS.



THE TEMPERATURE OUTLOOK FOR NOVEMBER, 2014 CALLS FOR ELEVATED CHANCES OF
ABOVE-NORMAL TEMPERATURES THROUGHOUT MUCH OF THE WESTERN CONUS, THE NORTHERN
ROCKY MOUNTAINS, THE NORTHERN GREAT PLAINS, MOST OF THE GREAT LAKES REGION, AND
MUCH OF THE NORTHEASTERN CONUS AND PARTS OF THE SOUTHEAST. THE CHANCES OF
ABOVE-NORMAL TEMPERATURES ARE ELEVATED THROUGHOUT THE ENTIRE STATE OF ALASKA.
THERE IS A BROAD CONSENSUS AMONG CLIMATE MODELS RUN AS PART OF THE NMME FOR
THIS FORECAST. THE CONFIDENCE FOR ABOVE NORMAL TEMPERATURES IS HIGHER IN
COASTAL AREAS OF THE WEST AND COASTAL ALASKA DUE TO ABOVE NORMAL SSTS
THROUGHOUT THE EASTERN PACIFIC, AND THE BERING SEA.



THE CHANCES FOR ABOVE-MEDIAN PRECIPITATION AMOUNTS ARE ENHANCED IN PARTS OF THE
SOUTHERN ROCKIES, TEXAS, PARTS OF THE SOUTHERN GREAT PLAINS AND PARTS OF THE
WESTERN GULF COAST. THIS SIGNAL IS STRONGLY FAVORED BY THE NMME, AND IS ALSO
INDICATED IN EL NINO COMPOSITES. BELOW-MEDIAN PRECIPITATION AMOUNTS ARE FAVORED
NEAR THE GREAT LAKES IN VIEW OF CONSISTENT SIGNALS FROM THE CFSV2. ABOVE-MEDIAN
PRECIPITATION AMOUNTS ARE SLIGHTLY FAVORED FOR THE ALASKA PANHANDLE AND PARTS
OF THE SOUTH COAST OF ALASKA DUE TO SUPPORT FROM THE CFSV2 AND IMME.



IN AREAS WHERE CLIMATE SIGNALS ARE WEAK SUCH THAT THE LIKELIHOODS OF MONTHLY
MEAN TEMPERATURES OR MONTHLY ACCUMULATED PRECIPITATION AMOUNTS ARE SIMILAR TO
CLIMATOLOGICAL PROBABILITIES, EQUAL CHANCES (EC) IS INDICATED.



THE MAIN FACTORS THAT USUALLY INFLUENCE THE MONTHLY CLIMATE OUTLOOK INCLUDE:

1) EL NINO AND LA NINA - WHICH COMPRISE ENSO. IMPACTS OF THESE EVENTS ARE
SUMMARIZED BY SEPARATING 3-MONTH OBSERVATIONS FROM THREE OR MORE DECADES INTO
EL NINO, NEUTRAL AND LA NINA SETS, AVERAGING EACH SEPARATELY, AND THEN
COMPUTING ANOMALIES. THESE ARE CALLED "COMPOSITES" AND USED AT TIMES TO
SUBJECTIVELY MODIFY THE FORECAST.

2) TRENDS - APPROXIMATED BY THE OCN TOOL AS THE DIFFERENCE BETWEEN THE MOST
RECENT 10-YEAR MEAN OF TEMPERATURE OR 15-YEAR MEAN OF PRECIPITATION FOR A GIVEN
LOCATION AND TIME OF YEAR AND THE 30-YEAR CLIMATOLOGY PERIOD (CURRENTLY
1981-2010).

3) THE TROPICAL 30-60 DAY OSCILLATION - CALLED THE MADDEN JULIAN OSCILLATION
(MJO) - AFFECTS CLIMATE VARIABILITY WITHIN SEASONS.

4) THE ARCTIC OSCILLATION (AO), THE SIMILAR NORTH ATLANTIC OSCILLATION (NAO),
AND THE PACIFIC NORTH AMERICAN (PNA) PATTERNS - WHICH AFFECT THE TEMPERATURE
ANOMALY PATTERN ESPECIALLY DURING BOREAL WINTER AND ARE GENERALLY CONSIDERED TO
HAVE LOW PREDICTABILITY.

5) THE PACIFIC DECADAL OSCILLATION (PDO) - AN ENSO-LIKE PATTERN OF CLIMATE
VARIABILITY AFFECTING THE TROPICS AND THE NORTH PACIFIC AND NORTH AMERICAN
REGIONS, BUT WHICH VARIES ON A MUCH LONGER TIME-SCALE THAN ENSO.

6) PERSISTENTLY DRY OR WET SOILS IN THE SPRING AND SUMMER AND SNOW AND ICE
COVER ANOMALIES IN THE WINTER. THESE FACTORS TEND TO PERSIST FOR LONG PERIODS
AND ACT AS A KIND OF MEMORY IN THE CLIMATE SYSTEM.

7) STATISTICAL FORECAST MODELS - CANONICAL CORRELATION ANALYSIS (CCA),
SCREENING MULTIPLE LINEAR REGRESSION (SMLR), CONSTRUCTED ANALOG (CA), AND
ENSEMBLE CCA (ECCA).

8) DYNAMICAL FORECAST MODELS - INCLUDING THE NCEP CLIMATE FORECAST SYSTEM
VERSION 2 (CFS) AND FOR THE ZERO-LEAD UPDATE FORECASTS THE NCEP GLOBAL ENSEMBLE
FORECAST SYSTEM (GEFS).  AN EXPERIMENTAL FORECAST SYSTEM, THE NATIONAL
MULTI-MODEL ENSEMBLE (NMME), COMPRISED OF SEVERAL DYNAMICAL MODELS IS ALSO USED.


FORECASTER: DAVID UNGER


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 DEC ... WILL BE ISSUED ON THU NOV 20 2014


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

$$



USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.