534  
FXUS02 KWBC 090658  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
258 AM EDT SUN JUN 9 2024  
 
VALID 12Z WED JUN 12 2024 - 12Z SUN JUN 16 2024  
 
...HEAT FOCUS SHIFTS FROM THE SOUTHWEST TO SOUTH TEXAS THIS WEEK  
AS HEAVY CONVECTIVE RAINFALL THREATS SHIFT FROM THE SOUTH-CENTRAL  
U.S. TO THE GULF OF MEXICO AND FLORIDA...  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
 
RECENT FORECAST SPREAD AND CONTINUITY ISSUES NOW SEEM SOMEWHAT  
LESS PROBLEMATIC IN A PATTERN WITH NEAR AVERAGE PREDICTABILITY  
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 INTO  
THE REGION. THE DETAILS OF HOW THIS INTERACTS WITH AN INCREASING  
MOISTURE FEED INTO/TOWARDS FLORIDA REMAINS HIGHLY UNCERTAIN. A  
HEAVY RAINFALL EVENT STILL SEEMS IN THE CARDS FOR PARTS OF  
FLORIDA, BUT WHERE THE RAINFALL AXIS SETS UP REMAINS VARIABLE.  
 
THE WPC MEDIUM RANGE PRODUCT SUITE WAS PRIMARILY DERIVED FROM A  
BLEND OF REASONABLY CLUSTERED GUIDANCE FROM THE 06 UTC GFS AND 00  
UTC ECMWF/UKMET/CANADIAN MODELS AND THEIR RESPECTIVE ENSEMBLE MEANS  
THROUGH MEDIUM RANGE TIME SCALES. GROWING FORECAST SPREAD SEEMS  
MAINLY TIED TO SMALLER SCALE EMBEDDED SYSTEM ISSUES THAT ARE OFTEN  
MITIGATED CONSISTENT WITH PREDICTABILTY BY A BROAD GUIDANCE  
BLENDING PROCESS THAT INCLUDES A SHIFT TOWARD INCREASED ENSEMBLE  
MEAN WEIGHTING INTO LONGER TIME FRAMES. THIS APPROACH MAINTAINS  
GOOD WPC PRODUCT CONTINUITY AND A COMPOSITE OF LATEST 00 UTC  
GUIDANCE REMAINS MOSTLY IN LINE FOR MUCH OF THIS FORECAST PERIOD.  
   
..WEATHER/HAZARDS HIGHLIGHTS  
 
A FRONT ACROSS THE SOUTH-CENTRAL PLAINS WILL COMBINE WITH SLOW  
MOVING UPPER SYSTEM ENERGY AND INSTABILITY TO OFFER A LINGERING THREAT  
FOR LOCAL HEAVY RAINFALL INTO WEDNESDAY. A WPC EXCESSIVE RAINFALL  
OUTLOOK (ERO) MARGINAL THREAT AREA IS DEPICTED. A MULTI-DAY PERIOD  
FAVORABLE FOR HEAVY RAINS SHOULD DEVELOP ACROSS THE FLORIDA  
PENINSULA AS WELL ABOVE MOISTURE POOLS ALONG AND SOUTH OF A  
WAVY/STALLING FRONT WITH AID FROM UPPER LEVEL IMPULSES/ENERGY BACK  
THROUGH AN UNSETTLED 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. WPC DAY  
4/WEDNESDAY AND DAY 5/THURSDAY ERO MARGINAL RISK AREAS INCLUDE  
MUCH OF THE CENTRAL AND SOUTHERN FLORIDA PENINSULA TO ACCOUNT FOR  
THE UNCERTAINTY, WITH A LOOMING THREAT INTO LATER WEEK AS WELL  
THERE AND WITH ANY ACTIVITY/MOISTURE FEED EMINATING OVER THE GULF.  
MEANWHILE, AN 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 PRODUCE  
MUCH WARMER THAN AVERAGE TEMPERATURES. THE HIGHEST TEMPERATURE  
ANOMALIES OF 10-20F ABOVE NORMAL ARE FORECAST FOR THE GREAT BASIN,  
SHIFTING EASTWARD AS THE WEEK PROGRESSES INTO THE ROCKIES AND  
PLAINS. IT WILL BE ESPECIALLY HOT ACROSS THE DESERT SOUTHWEST THEN  
SOUTH TEXAS GIVEN ELEVATED HEAT RISK AND HEAT INDEX THREAT VALUES.  
 
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  
 
 
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