070
FXUS07 KWBC 311900
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT TUE OCT 31 2023
30-DAY OUTLOOK DISCUSSION FOR NOVEMBER 2023
THE NOVEMBER TEMPERATURE AND PRECIPITATION OUTLOOKS ARE UPDATED CONSIDERING
CURRENT WEATHER PREDICTION CENTER (WPC) OUTLOOKS FOR WEEK 1, CLIMATE PREDICTION
CENTER (CPC) EXTENDED RANGE AND SUBSEASONAL OUTLOOKS, DYNAMICAL MODEL GUIDANCE
FOR WEEK 2 AND WEEKS 3-4, SNOW COVER, BACKGROUND CLIMATE STATES, AND RECENT
CLIMATE FORECAST SYSTEM VERSION 2 (CFSV2) MONTHLY FORECASTS OF TEMPERATURE AND
PRECIPITATION. EQUATORIAL SEA SURFACE TEMPERATURES (SSTS) ARE ABOVE AVERAGE
ACROSS THE CENTRAL AND EASTERN PACIFIC OCEAN, AND EL NIñO CONDITIONS ARE
OBSERVED. EVOLUTION OF THE MADDEN JULIAN OSCILLATION (MJO) IS UNCERTAIN DUE TO
DESTRUCTIVE INTERFERENCE FROM THE ACTIVE EL NIñO, AND AS SUCH, EL NIñO REMAINS
THE DOMINANT TELECONNECTION FOR TEMPERATURE AND PRECIPITATION OVER NORTH
AMERICA. OTHER INFLUENCING FACTORS FOR THE UPDATED NOVEMBER OUTLOOKS INCLUDE
SEA SURFACE TEMPERATURE (SST) ANOMALIES, WHICH ARE ABOVE NORMAL ALONG MUCH OF
THE COAST OF ALASKA, ALONG THE WEST COAST OF THE CONTIGUOUS UNITED STATES
(CONUS), IN THE GULF OF MEXICO, AND ALONG MOST OF THE EAST COAST. ADDITIONALLY,
ANOMALOUSLY HIGH SNOW COVER IS PRESENT IN THE NORTH-CENTRAL CONUS, AND SEA ICE
IS LOWER THAN THE AVERAGE NEAR ALASKA, WHICH ARE ALSO TAKEN INTO CONSIDERATION.
CPC 6-10 DAY FORECASTS (EARLY NOVEMBER) OF THE 500-HPA CIRCULATION PATTERN
FAVOR RIDGING OVER WESTERN CONUS AND TROUGHING OVER EASTERN CONUS, WITH SLIGHT
EASTWARD PROGRESSION OF THE PATTERN INTO THE 8-14 DAY PERIOD (EARLY TO
MID-NOVEMBER). DYNAMICAL MODEL PREDICTIONS OF WEEKS 3-4 (MID- TO LATE NOVEMBER)
500-HPA HEIGHTS GENERALLY FEATURE BROAD RIDGING ACROSS MUCH OF THE CONUS,
INDICATING THAT THE PATTERN MAY SHIFT NEAR THE MIDDLE OF THE MONTH. THUS, THE
PATTERN IS SOMEWHAT TRANSIENT FOR AT LEAST THE EASTERN PART OF THE CONUS, WHICH
ADDS UNCERTAINTY TO THE FORECAST OVER THE EAST, PARTICULARLY FOR TEMPERATURE.
THE UPDATED MONTHLY TEMPERATURE OUTLOOK REMAINS SIMILAR TO THE PREVIOUSLY
RELEASED OUTLOOK. A BROAD AREA OF ABOVE NORMAL TEMPERATURES IS FAVORED FOR THE
WESTERN HALF OF THE CONUS AND THE GULF STATES. GIVEN THE PERSISTENT RIDGING
OVER THE WESTERN CONUS IN EARLY TO MID-NOVEMBER, WEEK 34 GUIDANCE THAT FAVORS
BROAD RIDGING, AND RECENT MONTHLY CFSV2 FORECASTS OF TEMPERATURE THAT FAVOR
STRONG PROBABILITIES OF ABOVE NORMAL TEMPERATURES OVER THE WESTERN HALF OF THE
CONUS, CONFIDENCE ON ABOVE NORMAL TEMPERATURES IS INCREASED COMPARED TO THE
MID-MONTH OUTLOOK (50 TO 60 PERCENT). IN CONTRAST, THE EARLY NOVEMBER TROUGHING
OVER THE EASTERN CONUS IS EXPECTED TO BRING SHORT-LIVED BELOW NORMAL
TEMPERATURES INTO THE REGION, THOUGH LATER PARTS OF THE MONTH MAY SHIFT TOWARD
WEAKLY ABOVE NORMAL TEMPERATURE PROBABILITIES. ABOVE NORMAL TEMPERATURE
PROBABILITIES OVER THE GULF STATES ARE WEAKER (33 TO 40%) AND SHIFTED TOWARD
THE COAST COMPARED TO THE MID-MONTH OUTLOOK DUE TO THE POSSIBILITY OF SHORT
LIVED BELOW NORMAL TEMPERATURES THAT MAY DIP INTO THE REGION EARLY IN THE
MONTH. HOWEVER, MOST MODELS MAINTAIN SOME ABOVE NORMAL PROBABILITIES OVER THE
GULF STATES THROUGHOUT MUCH OF NOVEMBER AND GULF OF MEXICO SST ANOMALIES ARE
ABOVE NORMAL, BOTH OF WHICH SUPPORT THE WEAK TILT TOWARD ABOVE NORMAL. EQUAL
CHANCES OF ABOVE, NEAR, AND BELOW NORMAL TEMPERATURES (EC) ARE FAVORED FOR THE
REGION STRETCHING FROM THE NORTH CENTRAL CONUS TO THE EAST COAST, WHERE MODEL
UNCERTAINTY IS HIGH, AS WELL AS DUE TO ANOMALOUSLY HIGH SNOW COVER OVER PARTS
OF THE NORTH CENTRAL CONUS THAT COULD LEAD TO COOLER TEMPERATURES. A WEAK TILT
TOWARD BELOW NORMAL TEMPERATURES (33 TO 40 PERCENT) IS INDICATED FOR NEW
ENGLAND, WHERE MOST MODELS AND TOOLS MAINTAIN THE BELOW NORMAL SIGNAL
THROUGHOUT THE MONTH OF NOVEMBER. THE MAIN CHANGE FROM THE MID-MONTH
TEMPERATURE OUTLOOK OVER ALASKA IS EXPANSION OF THE REGION OF ABOVE NORMAL
TEMPERATURE PROBABILITIES GIVEN THE LOWER THAN AVERAGE SEA ICE AND ABOVE NORMAL
SSTS.
LARGER CHANGES ARE EVIDENT FOR THE UPDATED NOVEMBER PRECIPITATION OUTLOOK,
ESPECIALLY GIVEN MODEL UNCERTAINTY FOR THE MID-MONTH OUTLOOK WHICH LED TO LARGE
AREAS OF EC. PROBABILITIES OF ABOVE NORMAL PRECIPITATION ARE ELEVATED (50 TO 60
PERCENT) OVER THE NORTHWEST GIVEN EXPECTED EARLY TO MID-NOVEMBER ABOVE NORMAL
PRECIPITATION, AND IN AGREEMENT WITH THE EXPECTED EL NIñO TELECONNECTION. THE
AREA OF BELOW NORMAL PRECIPITATION, PREVIOUSLY FAVORED OVER PARTS OF THE GREAT
LAKES, IS EXPANDED TO INCLUDE PARTS OF THE MIDDLE MISSISSIPPI, LOWER
MISSISSIPPI, OHIO AND TENNESSEE VALLEY REGIONS DUE TO STRONG BELOW NORMAL
PRECIPITATION PROBABILITIES IN RECENT MONTHLY CFSV2 FORECASTS, SUPPORTED BY
WEEK 3-4 ECMWF FORECASTS OF PRECIPITATION. RECENT CFSV2 FORECASTS FAVOR BELOW
NORMAL PRECIPITATION ALL THE WAY TO THE GULF AND EAST COASTS, HOWEVER, A WEAK
TILT TOWARD ABOVE NORMAL IS MAINTAINED OVER COASTAL PARTS OF THE SOUTHEAST DUE
TO POTENTIAL FOR EL NIñO TELECONNECTIONS AND SUPPORTED BY WEEK 3-4 ECMWF
FORECASTS. EC IS FAVORED FOR THE MIDDLE ATLANTIC AND NORTHEAST, AGAIN DESPITE
BELOW NORMAL MONTHLY CFSV2 PREDICTIONS, DUE TO AMPLIFIED STORMINESS AND RISK OF
HEAVY PRECIPITATION ALONG THE COAST AS NOTED IN THE CPC U.S. WEEK-2 HAZARDS
OUTLOOK, HOWEVER, THERE IS CONSIDERABLE UNCERTAINTY SURROUNDING THIS FEATURE.
OVER ALASKA, THE UPDATED PRECIPITATION OUTLOOK REMAINS SIMILAR, WITH SLIGHT
DECREASE IN THE AREA OF FAVORED ABOVE NORMAL PRECIPITATION OVER THE NORTHERN
PARTS OF THE STATE, AND EXPANSION OF THE AREA OF FAVORED BELOW NORMAL
PRECIPITATION OVER THE SOUTHWESTERN PARTS OF THE STATE, CONSISTENT WITH UPDATED
DYNAMICAL MODEL FORECASTS.
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PREVIOUS MID-MONTH DISCUSSION BELOW
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EL NIñO CONDITIONS ARE CURRENTLY OBSERVED, AND EQUATORIAL SEA SURFACE
TEMPERATURES (SSTS) ARE ABOVE AVERAGE ACROSS THE CENTRAL AND EASTERN EQUATORIAL
PACIFIC OCEAN. THE TROPICAL PACIFIC ATMOSPHERE IS CONSISTENT WITH EL NIñO, AND
AS SUCH WE EXPECT EL NIñO TO BE THE DOMINANT TELECONNECTION FOR NOVEMBER,
THOUGH IMPACTS ARE GENERALLY WEAKER THAN DURING WINTER AND EARLY SPRING. WHILE
THE MADDEN JULIAN OSCILLATION (MJO) SHOWED SOME RENEWED ACTIVITY RECENTLY, AN
INCOHERENT MJO IS FAVORED IN FORECASTS OF THE REALTIME MULTIVARIATE MJO (RMM)
INDEX GIVEN DESTRUCTIVE INTERFERENCE FROM THE ONGOING EL NIñO AND AN EMERGING
POSITIVE INDIAN OCEAN DIPOLE (+IOD) EVENT. THUS, THE MJO WAS NOT SIGNIFICANTLY
CONSIDERED FOR THE NOVEMBER OUTLOOK. HOWEVER, GIVEN CLIMATOLOGY AND A
BROAD-SCALE ENVIRONMENT PREDICTED IN THE MODELS THAT IS CONSISTENT WITH A
CENTRAL AMERICAN GYRE (CAG) FORMATION OVER THE TROPICAL AMERICAS, CONDITIONS
ARE FAVORABLE FOR TROPICAL CYCLONE (TC) DEVELOPMENT OVER A BROAD AREA FROM THE
SOUTH OF MEXICO TO THE WESTERN ATLANTIC DURING EARLY PARTS OF NOVEMBER AS
FORECAST IN THE LATEST CPC GLOBAL TROPICS HAZARDS OUTLOOK (GTH). IN ADDITION TO
THESE INFLUENCING FACTORS, THE NOVEMBER TEMPERATURE AND PRECIPITATION OUTLOOKS
CONSIDER LOCAL SST ANOMALIES, DYNAMICAL MODEL GUIDANCE FROM THE NORTH AMERICAN
MULTI-MODEL ENSEMBLE (NMME), COPERNICUS MODEL SUITE (C3S), AND THE CLIMATE
FORECAST SYSTEM VERSION 2 (CFSV2), AS WELL AS STATISTICAL MODELS THAT INCLUDE
THE INFLUENCE OF TREND AND ENSO. WEEK 3-4 FORECASTS FROM CFSV2, ECMWF, AND
GEFSV12 FOR THE EARLY PART OF NOVEMBER WERE ALSO CONSIDERED, AS WAS THE
EXPECTED EVOLUTION FROM THE WEEK 2 FORECAST PERIOD.
THE NOVEMBER 2023 TEMPERATURE OUTLOOK FAVORS A BROAD AREA OF ABOVE NORMAL
TEMPERATURES FOR THE WESTERN CONTIGUOUS UNITED STATES (CONUS) STRETCHING INTO
THE SOUTHERN AND CENTRAL PLAINS, THE LOWER HALF OF THE MISSISSIPPI VALLEY, THE
TENNESSEE VALLEY, PARTS OF THE OHIO VALLEY, AND THE SOUTHEAST. WEEK 2
TEMPERATURE OUTLOOKS FEATURE A TILT TOWARD BELOW NORMAL TEMPERATURES OVER MUCH
OF THE WESTERN CONUS FOR THE PERIOD OF OCTOBER 25 THROUGH OCTOBER 1, THAT
SHIFTS EASTWARD TOWARD THE CENTRAL CONUS FOR OCTOBER 26 THROUGH NOVEMBER 1. IN
CONTRAST, CFSV2, GEFSV12, AND ECMWF PREDICTIONS OF WEEK 3 AND 4 TEMPERATURES
THROUGH MID-NOVEMBER BROADLY FAVOR WARMING OVER CONUS, INCLUDING THE WESTERN
AND CENTRAL PARTS OF THE COUNTRY. THIS SUGGESTS THAT ANY POTENTIAL COOLER START
TO NOVEMBER, PARTICULARLY OVER THE WESTERN CONUS, WILL BE A TRANSIENT FEATURE
WITH UNCERTAINTY ON HOW LONG IT MAY PERSIST. WHILE RECENT FORECASTS FROM CFSV2
FAVOR STRONG PROBABILITIES FOR ABOVE NORMAL TEMPERATURES OVER THE WESTERN THIRD
OF THE CONUS, PROBABILITIES IN THE NOVEMBER TEMPERATURE OUTLOOK ARE
COMPARATIVELY DAMPED (40 TO 50 PERCENT) TO REFLECT THIS UNCERTAINTY. HIGHER
PROBABILITIES (40 TO 50 PERCENT) OF ABOVE NORMAL TEMPERATURES ARE INDICATED
OVER THE SOUTHWEST WHERE DYNAMICAL MODELS AGREE. THE TILT TOWARD ABOVE NORMAL
TEMPERATURES OVER THE WEST IS ALSO SUPPORTED BY THE TYPICAL EL NIñO
TELECONNECTION, WHICH FAVORS ABOVE NORMAL OR MILDER TEMPERATURES OVER THE
WESTERN HALF OF THE CONUS. IN CONTRAST, BELOW NORMAL TEMPERATURES ARE MORE
TYPICAL OVER OVER THE EASTERN HALF OF CONUS DURING EL NIñO, HOWEVER, THIS IS AT
ODDS WITH CFSV2 PREDICTIONS THAT FAVOR (RELATIVELY) STRONG PROBABILITIES FOR
ABOVE NORMAL TEMPERATURES OVER PARTS OF THE MISSISSIPPI, OHIO, AND TENNESSEE
VALLEYS AND THE SOUTHEAST, AND WITH NMME AND C3S PREDICTIONS THAT ALSO SLIGHTLY
TILT ABOVE NORMAL. A WEAK TILT TOWARD ABOVE NORMAL IS MAINTAINED OVER PARTS OF
THE SOUTHEASTERN CONUS (33 TO 40 PERCENT), WITH HIGHER PROBABILITIES (40 TO 50
PERCENT) OVER PARTS OF THE GULF STATES AND FLORIDA PENINSULA WHERE THERE IS
STRONGER MODEL AGREEMENT, AND COINCIDENT WITH ABOVE AVERAGE SST ANOMALIES.
EQUAL CHANCES (EC) OF ABOVE, BELOW, AND NEAR NORMAL TEMPERATURES ARE INDICATED
FOR THE NORTHERN PLAINS, GREAT LAKES, PARTS OF THE MID-ATLANTIC AND NEW ENGLAND
WHERE STATISTICAL TOOLS AND DYNAMICAL MODELS SHOWED WEAK OR CONFLICTING
SIGNALS. MIXED POSITIVE AND NEGATIVE SST ANOMALIES OFF THE COAST OF NEW ENGLAND
ADDS TO UNCERTAINTY. FINALLY, A GRADIENT OF ABOVE NORMAL TEMPERATURE
PROBABILITIES TO EC IS FAVORED FOR NORTHERN ALASKA TO SOUTHERN ALASKA, WITH THE
STRONGEST PROBABILITIES OF ABOVE NORMAL TEMPERATURES FOUND OVER THE
NORTHERNMOST PART OF THE STATE WHERE THERE WAS STRONG MODEL AGREEMENT AND
ANOMALOUSLY WARM SSTS.
MORE UNCERTAINTY IS APPARENT IN THE NOVEMBER 2023 PRECIPITATION OUTLOOK, WITH
EC INDICATED FOR A LARGE PART OF THE CONUS GIVEN WEAK AND INCONSISTENT MODEL
RESULTS, AND SIGNIFICANT DAY TO DAY DIFFERENCES IN RECENT CFSV2 PREDICTIONS. A
REGION OF FAVORED ABOVE NORMAL PRECIPITATION IS INDICATED FROM PARTS OF TEXAS
EASTWARD ACROSS THE SOUTHEAST AND UP THE EAST COAST OF THE CONUS. THIS REGION
OF ELEVATED ABOVE NORMAL PRECIPITATION PROBABILITIES IS SUPPORTED BY THE NMME
AND C3S, AND AGREES WITH THE EXPECTED EL NIñO TELECONNECTION AND THE POTENTIAL
FOR INCREASED PRECIPITATION THAT MAY BE ASSOCIATED WITH ELEVATED TC
DEVELOPMENT. HOWEVER, PROBABILITIES ARE DAMPED GIVEN CFSV2 GUIDANCE THAT FAVORS
A TILT TOWARD BELOW NORMAL PRECIPITATION PROBABILITIES. A SLIGHT TILT TOWARD
BELOW NORMAL PRECIPITATION IS DEPICTED OVER THE WESTERN GREAT LAKES WHERE NMME,
C3S, CFSV2, AND EXPECTED EL NIñO TELECONNECTIONS ALL SUPPORT BELOW NORMAL. BOTH
STATISTICAL AND DYNAMICAL MODELS SUPPORT ENHANCED PROBABILITIES OF ABOVE NORMAL
OVER NORTHERN ALASKA. GUIDANCE IS MIXED FOR THE SOUTHERN COAST, BUT RECENT
CFSV2 FORECASTS CONSISTENTLY FAVOR STRONGER PROBABILITIES OF BELOW NORMAL
PRECIPITATION, ADDITIONALLY SUPPORTED BY A SUBSET NMME AND C3S MODELS, AND THUS
BELOW NORMAL PRECIPITATION PROBABILITIES ARE ELEVATED OVER COASTAL REGIONS.
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 DEC ... WILL BE ISSUED ON THU NOV 16 2023
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
CLICK HERE TO GO TO PREVIOUS BULLETINS.
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