643
FXUS07 KWBC 311900
PMD30D
PROGNOSTIC DISCUSSION FOR MONTHLY OUTLOOK
NWS CLIMATE PREDICTION CENTER COLLEGE PARK MD
300 PM EDT FRI MAY 31 2024
30-DAY OUTLOOK DISCUSSION FOR JUNE 2024
THE UPDATED JUNE TEMPERATURE AND PRECIPITATION OUTLOOKS PRIMARILY UTILIZED
MODEL GUIDANCE ACROSS MULTIPLE FORECAST TIME SCALES THAT INCLUDED SHORT-,
EXTENDED- AND SUBSEASONAL-RANGE INFORMATION. THE MJO REMAINED DISORGANIZED AND
WAS NOT A SUBSTANTIAL PLAYER IN THE JUNE UPDATED OUTLOOK. COASTAL SSTS AND LAND
SURFACE ANOMALIES CONTINUED TO BE CONSIDERED IN PREPARATION OF THE OUTLOOK.
THE UPDATED JUNE TEMPERATURE OUTLOOK MAINTAINED MUCH OF THE FORECAST FROM THE
MIDDLE OF THE MONTH OUTLOOK. AN EXTENSIVE AREA OF FAVORED ABOVE-NORMAL
TEMPERATURES REMAINS HIGHLIGHTED ALONG THE SOUTHERN TIER OF THE U.S., FOR THE
CENTRAL AND SOUTHERN PLAINS, THE SOUTHWEST, MUCH OF THE ROCKIES AND PACIFIC
NORTHWEST. MODEL GUIDANCE ACROSS TIME SCALES SUPPORTS INCREASING PROBABILITIES
OF MONTHLY MEAN TEMPERATURES FOR MUCH OF THE WESTERN CONUS. SHORT- AND
SUBSEASONAL-RANGE MODEL GUIDANCE SUPPORTS INCREASING FORECAST COVERAGE FOR
ABOVE-NORMAL TEMPERATURES TO INCLUDE THE NORTHERN PLAINS AND PORTIONS OF THE
GREAT LAKES AND NORTHEAST.
THERE WILL BE PERIODS OF TROUGHING OVER THE FIRST COUPLE OF WEEKS OF JUNE IN
THE EAST-CENTRAL U.S. MOST LIKELY RESULTING IN BELOW-NORMAL TEMPERATURES FOR
AREAS IN THE OHIO VALLEY, TENNESSEE VALLEY AND GREATER MIDWEST. FAVORED WARMER
THAN NORMAL TEMPERATURES EARLY IN THE MONTH AND AFTER MID-MONTH ARE FORECAST TO
OFFSET THIS AND ALONG WITH A RECENT WARMER THAN OBSERVED MODEL BIAS ACROSS
ENSEMBLE SYSTEMS, EQUAL-CHANCES (EC) IS DEPICTED IN THE OHIO VALLEY, TENNESSEE
VALLEY AND MID-ATLANTIC DUE TO THE UNCERTAINTY IN THE FINAL MONTHLY MEAN JUNE
TEMPERATURES.
GIVEN CONSISTENT MODEL GUIDANCE FOR A HEAT WAVE TO IMPACT MUCH OF THE WESTERN
U.S. INCLUDING CALIFORNIA EARLY IN THE MONTH AND GENERALLY WARMER THAN NORMAL
CONDITIONS FORECAST ACROSS TIME SCALES, THE FAVORED BELOW-NORMAL TEMPERATURES
ALONG THE CALIFORNIA COAST IS REMOVED. EVEN THOUGH COASTAL SSTS REMAIN
BELOW-AVERAGE, IT IS UNLIKELY THAT BELOW-NORMAL MONTHLY MEAN TEMPERATURES ARE
REALIZED IN THIS REGION. COASTAL SSTS AND MODEL GUIDANCE SUPPORTS AN AREA OF
FAVORED BELOW-NORMAL TEMPERATURES FOR SOUTHWEST ALASKA AND PARTS OF THE SOUTH
COAST. MOREOVER, MODEL GUIDANCE ACROSS MULTIPLE TIME SCALES SUPPORTS THE
ADJUSTMENT OF FAVORED ABOVE-NORMAL TEMPERATURES TO NOW BE SITUATED OVER THE
ENTIRE NORTH SLOPE IN ALASKA.
FOR PRECIPITATION, MORE CHANGES ARE REQUIRED THAN THAT FOR THE UPDATED JUNE
TEMPERATURE OUTLOOK. STRONG RIDGING ACROSS THE WEST CENTRAL U.S. FORECAST FOR
MUCH OF THE PERIOD FAVORS BELOW-NORMAL MONTHLY TOTAL PRECIPITATION TO SHIFT
NORTHWARD, AS COMPARED TO THE MID-MONTH OUTLOOK, TO THE NORTHERN ROCKIES AND
NORTHERN HIGH PLAINS. THE FAVORED RIDGE-TROUGH FORECAST PATTERN OVER THE CONUS
FROM WEST TO EAST FOR MUCH OF THE FIRST HALF OF JUNE SUPPORTS A DOWNSTREAM MEAN
FRONTAL ZONE FROM THE SOUTHEAST WESTWARD ACROSS THE SOUTHERN PLAINS TO THE
SOUTH-CENTRAL ROCKIES. THIS IS FURTHER SOUTHWARD THAN DESCRIBED IN THE
MID-MONTH OUTLOOK DISCUSSION AND SO THE ABOVE-NORMAL PRECIPITATION AREA IS
SHIFTED SOUTHWESTWARD AND EXTENDS FROM THE SOUTHEAST WESTWARD TO THE SOUTH
CENTRAL ROCKIES.
HIGH ODDS FOR ABOVE-NORMAL PRECIPITATION IS FORECAST FOR A SMALL REGION IN THE
FAR PACIFIC NORTHWEST. HIGH PRECIPITATION AMOUNTS DURING THE FIRST WEEK OF JUNE
WILL LIKELY PRODUCE AMOUNTS ALREADY IN THE ABOVE-NORMAL CATEGORY GIVEN THE
POINT IN THE SEASONAL CYCLE - EVEN WITH POTENTIAL LITTLE ADDITIONAL
PRECIPITATION DURING AN INCREASING DRY TIME OF YEAR. FORECAST TROUGHING IN
PROXIMITY TO THE GREAT LAKES FAVORS UNSETTLED CONDITIONS DOWNSTREAM AND SO
ELEVATED ODDS OF ABOVE-NORMAL PRECIPITATION IS FORECAST FOR THE NORTHEAST. THE
FORECAST FOR ALASKA IS UNCHANGED.
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****** MID-MONTH PREVIOUS DISCUSSION ******
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DURING THE FIRST HALF OF MAY 2024, THE TRANSITION FROM EL NINO TO ENSO NEUTRAL
CONTINUES AS SHOWN BY BOTH OCEANIC AND ATMOSPHERIC INDICATORS. A FURTHER
TRANSITION TO LA NINA REMAINS FAVORED TO OCCUR SOMETIME DURING THE SUMMER
MONTHS. THE MJO IS CURRENTLY NOT WELL ORGANIZED. ALTHOUGH SOME MODEL FORECASTS
OF THE RMM INDEX DO INDICATE SOME IMPROVEMENT IN THE SIGNAL OVER THE NEXT
COUPLE OF WEEKS, IT SEEMS POTENTIALLY TRANSIENT IN NATURE WITH HIGH
UNCERTAINTY. ALSO, GIVEN THE TIME WITHIN THE SEASONAL CYCLE, THERE IS LOW
CONFIDENCE IN ANY RELIABLE IMPACTS TO THE U.S. AND SO THE MJO DID NOT PLAY ANY
SUBSTANTIAL ROLE IN THE MONTHLY OUTLOOK. SOIL MOISTURE ANOMALIES, COASTAL SEA
SURFACE TEMPERATURES (SSTS) AND LONG-TERM TEMPERATURE TRENDS ARE CONSIDERED IN
PREPARATION OF THE JUNE 2024 OUTLOOK.
THE JUNE 2024 TEMPERATURE OUTLOOK DEPICTS ELEVATED ODDS FOR ABOVE-NORMAL
MONTHLY MEAN TEMPERATURES FOR A REGION FROM EASTERN MAINLAND ALASKA TO THE
PACIFIC NORTHWEST AND NORTHERN ROCKIES SOUTH AND EAST TO THE SOUTHWEST CONUS
AND EASTWARD TO INCLUDE THE SOUTHERN PLAINS AND SOUTHEAST. SUBSEASONAL MODEL
GUIDANCE (ECMWF, GEFS, AMONG OTHERS) FAVORS MEAN RIDGING FOR THE WEST-CENTRAL
CONUS NORTHWARD ACROSS WESTERN CANADA TO EASTERN ALASKA IN EARLY JUNE. THE
POTENTIAL RIDGING ELEVATES ODDS FOR WARMER THAN NORMAL CONDITIONS FOR THE FIRST
THIRD OF JUNE FOR MUCH OF THIS AREA WITH DRY SOIL MOISTURE CONDITIONS ADDING
SUPPORT FOR AREAS IN THE PACIFIC NORTHWEST, NORTHERN ROCKIES AND PARTS OF THE
SOUTHWEST AND SOUTHERN HIGH PLAINS. THE MAJORITY OF THE NMME AND C3S MONTHLY
MODEL PREDICTIONS ALSO INDICATE ABOVE-NORMAL TEMPERATURES FOR THIS REGION.
SUBTROPICAL RIDGING ALONG THE SOUTHERN TIER OF THE U.S. SUPPORTS ELEVATED ODDS
FOR ABOVE-NORMAL TEMPERATURES FOR THE SOUTHERN PLAINS, GULF COAST AND
SOUTHEAST. HIGHEST ODDS ARE FORECAST FOR THE EASTERN SOUTHWEST AND TEXAS WHERE
RIDGING, DRY SURFACE CONDITIONS AND POSITIVE LONG-TERM TEMPERATURE TRENDS
CO-EXIST.
BELOW-NORMAL MONTHLY MEAN TEMPERATURES ARE FAVORED FOR TWO SMALL AREAS FOR
COASTAL CENTRAL AND SOUTHERN CALIFORNIA AND ALSO FOR PARTS OF SOUTHWEST ALASKA.
COOLER THAN NORMAL OCEAN SURFACE TEMPERATURES CONTRIBUTE TO THESE FORECASTS
WITH FAVORED MEAN FORECAST TROUGHING NEAR AND ALONG THE SOUTHERN HALF OF THE
WEST COAST ALSO SUPPORTING BELOW-NORMAL TEMPERATURES FOR THE CALIFORNIA REGION.
A DIPOLE FORECAST FOR ENHANCED ODDS FOR BELOW-NORMAL (ABOVE-NORMAL)
TEMPERATURES WAS CONSIDERED FOR PARTS OF THE MIDWEST, OHIO VALLEY AND
MID-ATLANTIC (NORTHERN GREAT LAKES AND NEW ENGLAND) RESPECTIVELY. CONFLICTING
MODEL FORECAST GUIDANCE, SOIL MOISTURE CONDITIONS AND LONG-TERM TEMPERATURE
TRENDS, HOWEVER, MADE HIGHLIGHTING THESE AREAS IN THE OUTLOOK A LOW CONFIDENCE
FORECAST AT THE CURRENT TIME. THEREFORE, EQUAL CHANCES (EC) FOR EITHER ABOVE-,
NEAR- OR BELOW-NORMAL TEMPERATURES IS FORECAST FOR THE MID-MONTH OUTLOOK AND
REEVALUATED FOR THE END OF THE MONTH UPDATE.
FOR PRECIPITATION, ELEVATED ODDS FOR ABOVE-NORMAL MONTHLY TOTAL PRECIPITATION
AMOUNTS ARE FORECAST FOR A REGION FROM THE CENTRAL PLAINS EASTWARD ACROSS THE
OHIO VALLEY TO THE MID-ATLANTIC. BOTH SUBSEASONAL AND MONTHLY MODEL PREDICTIONS
INDICATE THE TENDENCY FOR A MEAN FRONTAL ZONE IN THE INTERIOR OF THE CONUS FROM
THE ATLANTIC SEABOARD WESTWARD TO THE CENTRAL CONUS. THE LOCATION OF THIS
WETTER THAN NORMAL AREA IS QUITE VARIABLE AMONGST THE MODEL SOLUTIONS SO THE
FORECAST AREA IS GENERALLY PLACED IN THE MOST LIKELY REGION AFTER CONSIDERING
ALL THE AVAILABLE INFORMATION.
DRIER THAN NORMAL MONTHLY PRECIPITATION AMOUNTS ARE FORECAST FOR EASTERN AREAS
OF THE SOUTHWEST AS WELL AS PARTS OF THE PACIFIC NORTHWEST AND NORTHERN
ROCKIES. NMME AND C3S MODEL MONTHLY PREDICTIONS ARE IN VERY GOOD AGREEMENT THIS
MONTH SIMILAR TO LAST SEVERAL MONTHLY FORECAST CYCLES FOR BELOW-NORMAL
PRECIPITATION FOR THE EASTERN SOUTHWEST, SOUTH-CENTRAL ROCKIES AND MUCH OF
TEXAS IMPLYING A LATER AND/OR WEAKER SOUTHWEST MONSOON ONSET. SUBSEASONAL MODEL
GUIDANCE IN EARLY JUNE INDICATES POSITIVE 500-HPA HEIGHT ANOMALIES IN THE
NORTHEAST PACIFIC OCEAN IMPLYING A NORTHWARD SHIFTED STORM TRACK AND SO
ELEVATED ODDS FOR BELOW-NORMAL PRECIPITATION IS FORECAST IN THE PACIFIC
NORTHWEST AND NORTHERN ROCKIES. SOME NMME AND C3S MODEL GUIDANCE ALSO SUPPORTS
THIS FORECAST.
FAVORED FORECAST RIDGING IN WESTERN CANADA CAN SOMETIMES ENHANCE WARM SEASON
PRECIPITATION FOR FAR EAST-CENTRAL MAINLAND ALASKA SO A SLIGHT TILT TOWARD
ABOVE-NORMAL PRECIPITATION IS HIGHLIGHTED IN THIS AREA FOR JUNE 2024.
REMAINING AREAS DEPICTED IN WHITE ARE FORECASTS OF EC FOR EITHER ABOVE-, NEAR-
OR BELOW-NORMAL PRECIPITATION AMOUNTS DUE TO WEAK CLIMATE SIGNALS AND/OR LOW
HISTORICAL FORECAST SKILL OR RELIABILITY.
FORECASTER: JON GOTTSCHALCK
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 JUL ... WILL BE ISSUED ON THU JUN 20 2024
THESE OUTLOOKS ARE BASED ON DEPARTURES FROM THE 1991-2020 BASE PERIOD.
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