774
FXUS02 KWBC 081900
PMDEPD
EXTENDED FORECAST DISCUSSION
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
300 PM EDT SAT JUN 8 2024
VALID 12Z TUE JUN 11 2024 - 12Z SAT JUN 15 2024
...HOT TEMPERATURE SHIFT FROM THE WEST/SOUTHWEST TO THE PLAINS NEXT
WEEK AS DOWNSTREAM HEAVY CONVECTIVE RAINFALL THREATS AFFECT THE
SOUTH-CENTRAL STATES AND FROM THE GULF OF MEXICO INTO FLORIDA...
..OVERVIEW
THERE IS NOW BETTER AGREEMENT IN THE GUIDANCE THAT AN ELONGATED
UPPER LOW OVER SOUTHERN-EASTERN CANADA WILL SPLIT, SENDING A
TROUGH THROUGH THE NORTHEAST INTO TUESDAY AND A SECONDARY SHORTWAVE
THROUGH THE NORTHERN PLAINS/GREAT LAKES TUESDAY-WEDNESDAY. SLOW
MOVING SOUTHERN STREAM ENERGY WILL KEEP UNSETTLED CONDITIONS AND
HEAVY RAINFALL POTENTIAL PARTICULARLY ACROSS THE SOUTHERN PLAINS
AND LOWER MISSISSIPPI VALLEY EARLY-MID NEXT WEEK, WITH AN INHERENT
STRONGER THREAT SIGNAL FOR A MULTI-DAY WET PERIOD ACROSS THE
FLORIDA PENINSULA ALONG WITH BUILDING ENERGIES AND CONVECTION TO
MONITOR OVER A WARMED GULF OF MEXICO.
UPPER RIDGING OVER THE WEST/SOUTHWEST WILL GRADUALLY WORK INTO THE
SOUTH-CENTRAL U.S. WITH SUMMER HEAT AS A CLOSED LOW WORKS SLOWLY
TO THE SOUTHWEST FROM THE TROPICAL EAST PACIFIC. MEANWHILE, THE
PATTERN WILL FAVOR MULTIPLE BUT MOSTLY DRY PACIFIC UPPER TROUGH AND
COOLING FRONTAL INTRUSIONS ACROSS AN UNSETTLED NORTHWESTERN U.S..
..GUIDANCE/PREDICTABILITY ASSESSMENT
RECENT GUIDANCE FORECAST SPREAD AND RUN TO RUN CONTINUITY ISSUES
CONTINUE TO IMPROVE COMPARED TO THE PAST DAY OR TWO OF RUN CYCLES
FOR AT LEAST THE FIRST HALF OF THE UPCOMING MEDIUM RANGE FORECAST
PERIOD. THIS BOLSTERS FORECAST CONFIDENCE BACK TO NEAR NORMAL
LEVELS OVERALL, ALBEIT STILL WITH STANDARD AND WIDESPREAD WARM
SEASON VARIANCES IN THE DETAILS. THE GREATEST REGION OF UNCERTAINTY
REMAINS OVER THE GULF OF MEXICO AS LOWER HEIGHTS ALOFT MOVE IN TO
THE REGION. THE DETAILS OF HOW THIS INTERACTS WITH AN INCREASING
MOISTURE FEED INTO/TOWARDS FLORIDA REMAINS HIGHLY UNCERTAIN.
CONFIDENCE IS INCREASING TOWARDS A HEAVY RAINFALL EVENT FOR
FLORIDA, BUT EXACTLY WHERE THE RAINFALL AXIS SETS UP IS UNKNOWN AND
HIGHLY VARIABLE.
ACCORDINGLY, THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY
DERIVED FROM A COMPOSITE BLEND OF REASONABLY WELL CLUSTERED
GUIDANCE FROM THE 06 UTC GFS AND 00 UTC ECMWF/UKMET/CANADIAN
MODELS VALID FOR TUESDAY INTO THURSDAY. GROWING FORECAST SPREAD
SEEMS MANAGEABLE BUT SUFFICIENT TO FAVOR A SWITCH TO MORE INCLUSION
OF THE ENSEMBLE MEANS TO MITIGATE THE DETAILS DIFFERENCES. THIS
APPROACH MAINTAINS GOOD CONTINUITY WITH THE PREVIOUS WPC FORECAST
AS WELL.
..WEATHER/HAZARDS HIGHLIGHTS
A WAVY FRONT ACROSS THE SOUTH-CENTRAL PLAINS AND VICINITY WILL
COMBINE WITH SLOW MOVING UPPER ENERGY TO CONTINUE A THREAT FOR
HEAVY RAINFALL INTO DAY 4/TUESDAY FROM WETTENED OKLAHOMA TO
NORTHERN TEXAS, WITH ADDITIONAL THREAT SHIFTING INTO THE LOWER
MISSISSIPPI VALLEY INTO DAY 5/WEDNESDAY. WPC EXCESSIVE RAINFALL
OUTLOOK (ERO) MARGINAL THREAT AREAS ARE DEPICTED FOR EACH DAY. A
MULTI-DAY PERIOD FAVORABLE FOR HEAVY RAINS WILL ALSO DEVELOP ACROSS
THE FLORIDA PENINSULA STARTING TUESDAY AS WELL ABOVE MOISTURE
POOLS ALONG/SOUTH OF A THE WAVY/STALLING FRONT WITH SOME AID FROM
WEAK UPPER LEVEL IMPULSES/ENERGY THROUGH THE GULF OF MEXICO. THERE
IS A LOT OF UNCERTAINTY IN THE DETAILS AND MUCH OF THE STATE IS IN
A DROUGHT. STILL, SOME THREAT FOR HIGH RAIN RATES EXISTS, AND ITS
POSSIBLE MUCH OF THE THREAT MAY MANIFEST FOR MORE SUSCEPTABLE
URBANIZED AREAS. DAY 4/5 WPC ERO MARGINAL RISK AREAS HAVE BEEN
CONTINUED TO INCLUDE THE CENTRAL AND SOUTHERN PENINSULA TO ACCOUNT
FOR THE UNCERTAINTY, WITH A LOOMING THREAT INTO LATER NEXT WEEK AS
WELL THERE AND WITH ANY ACTIVITY/MOISTURE FEED EMINATING OVER THE
GULF. INCREASING PRECIPITATION THREAT ACROSS MUCH OF THE CENTRAL
AND NORTHERN PLAINS EMERGES LATE PERIOD WITH TROUGHING SHIFTING
NORTHEASTWARD INTO THE REGION FROM THE SOUTHWEST.
AN AMPLIFIED MEAN UPPER RIDGE SLATED TO SLOWLY SHIFT FROM THE
WEST/SOUTHWEST TO THE SOUTH-CENTRAL U.S. WILL CONTINUE TO CAUSE
MUCH WARMER THAN AVERAGE TEMPERATURES. THE HIGHEST TEMPERATURE
ANOMALIES OF 10-20F ABOVE NORMAL ARE FORECAST FOR THE GREAT BASIN,
WARMING A BIT AND EXPANDING EASTWARD AS THE WEEK PROGRESSES INTO
THE ROCKIES AND PLAINS. TEMPERATURES WILL ALSO RISE A FEW DEGREES
IN THE DESERT SOUTHWEST TO BRING SOME TEMPERATURES BACK ABOVE 110F,
WITH HEAT RISK THREAT LEVELS MOSTLY AT MODERATE TO MAJOR LEVELS.
HEAT SHOULD BUILD AGAIN ACROSS SOUTH TO SOUTH TEXAS AS WELL, WITH
HEAT INDICES BACK UP TO AROUND 110.
SANTORELLI/SCHICHTEL
ADDITIONAL 3-7 DAY HAZARD INFORMATION CAN BE FOUND ON THE WPC MEDIUM
RANGE HAZARDS OUTLOOK CHART AT:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/THREATS/THREATS.PHP
WPC MEDIUM RANGE 500MB HEIGHTS, SURFACE SYSTEMS, WEATHER GRIDS,
QUANTITATIVE PRECIPITATION FORECAST (QPF), EXCESSIVE RAINFALL
OUTLOOK (ERO), WINTER WEATHER OUTLOOK (WWO) PROBABILITIES, HEAT
INDICES, AND KEY MESSAGES CAN BE ACCESSED FROM:
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST500_WBG.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/MEDR/5DAYFCST_WBG_CONUS.GIF
HTTPS://WWW.WPC.NCEP.NOAA.GOV/5KM_GRIDS/5KM_GRIDSBODY.HTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/QPF/DAY4-7.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=ERO
HTTPS://WWW.WPC.NCEP.NOAA.GOV/WWD/PWPF_D47/PWPF_MEDR.PHP?DAY=4
HTTPS://WWW.WPC.NCEP.NOAA.GOV/HEAT_INDEX.SHTML
HTTPS://WWW.WPC.NCEP.NOAA.GOV/#PAGE=OVW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page