044  
FXUS02 KWBC 070700  
PMDEPD  
 
EXTENDED FORECAST DISCUSSION  
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD  
300 AM EDT TUE MAY 7 2024  
 
VALID 12Z FRI MAY 10 2024 - 12Z TUE MAY 14 2024  
 
   
..GUIDANCE/PREDICTABILITY ASSESSMENT  
 
THE 12 UTC GFS/ECMWF/CANADIAN MODEL SOLUTIONS SEEM BEST CLUSTERED  
VALID FOR FRIDAY AND SATURDAY IN A PATTERN WITH GOOD 12 UTC CYCLE  
ENSEMBLE SUPPORT AND NEAR TO ABOVE NORMAL PREDICTABILITY AND  
CONTINUITY, GENERALLLY IN LINE WITH THE 01 UTC NATIONAL BLEND OF  
MODELS (NBM). A COMPOSITE BLEND OFFERS GOOD SYSTEM DETAIL, WITH  
THE MOST FORECAST SPREAD RELATING TO MODERATE COASTAL GENESIS AND  
DEVELOPMENT UP OFF THE EAST COAST. 12 UTC GUIDANCE TRENDED TOWARD  
BETTER CLUSTERING COMPARED TO THE MORE VARIED 18 UTC GFS/GEFS. THE  
12 UTC GUIDANCE CYCLE BEST FITS LATEST MACHINE-LEARNING GUIDANCE.  
LATEST 00 UTC GUIDANCE REMAINS IN LINE, BUT THE ECMWF IS DELAYED.  
 
FORECAST SPREAD AND MODEL CYCLE TO CYCLE CONTINUITY ISSUES  
INCREASE MORE SIGNIFICANTLY OVER THE WEEKEND INTO NEXT WEEK OVER  
THE WEST IN DEVELOPING SPLIT FLOW AND ESPECIALLY WITH AMPLITUDE AND  
EXTENT OF DIGGING OF NORTHERN STREAM ENERGIES DOWN INTO THE NORTH-  
CENTRAL AND/OR EASTERN U.S.. WPC PRODUCTS AT THESE LONGER TIME  
FRAMES WERE MAINLY DERIVED FROM MORE COMPATIBLE GUIDANCE FROM THE  
12 UTC ECMWF/NAEFS ENSEMBLE MEANS AND THE 01 UTC NBM ALONG WITH  
WPC APPLIED MANUAL EDITS TO MAINTAIN MAX WPC PRODUCT CONTINUITY,  
ALBEIT WITH LESS THAN IDEAL SYSTEM DETAIL GIVEN GROWING UNCERTANTY.  
THE LATEST 00 UTC MODELS REMAINS VARIED WITH RUN TO RUN ISSUES.  
   
..WEATHER/HAZARDS HIGHLIGHTS  
 
A MAIN PARENT LOW AND FRONTAL SYSTEM WORKING TOWARD THE NORTHEAST  
FRIDAY WILL HELP FOCUS GENERALLY MODERATE RAINFALL, WITH ACTIVITY  
AIDED AND PROLONGED SATURDAY AS UNCERTAIN DOWNSTREAM ENERGY  
TRANFERENCE LEADS TO COASTAL LOW GENESIS. ADDITIONAL BUT UNCERTAIN  
UPSTREAM NORTHERN STREAM SYSTEMS MAY PERIODICALLY OFFER BOUTS OF  
MAINLY LIGHTER RAINS FROM THE NORTH-CENTRAL U.S. TO THE GREAT  
LAKES/NORTHEAST SUNDAY-NEXT TUESDAY.  
 
MEANWHILE TO THE SOUTH, A COOLING AND TRAILING/WAVY FRONT WILL  
MODERATE LEAD WARMTH WHILE WORKING THROUGH THE SOUTHEAST TO THE  
GULF OF MEXICO AND NORTHERN MEXICO. A WPC DAY4/FRIDAY EXCESSIVE  
RAINFALL OUTLOOK MARGINAL RISK AREA IS IN PLACE FOR PARTS OF THE  
SOUTHEAST GIVEN LINGERING DEEP MOISTURE/INSTABILITY AND FAVORABLE  
UPPER JET/DIFFLUENCE SUPPORT. THIS SLOWING FRONT AND A REINFORCING  
FRONT/UPPER IMPULSES ARE EXPECTED TO PERIODICALLY FOCUS  
PREDIPITATION FROM THE SOUTHERN ROCKIES/PLAINS OUT THROUGH THE GULF  
OF MEXICO AND FLORIDA OVER THE WEEKEND INTO NEXT WEEK. GUIDANCE  
REMAINS VARIED AT THESE LONGER TIME FRAMES, BUT LATEST SIGNAL  
TRENDS SUGGEST THE MAIN AREAS TO MONITOR FOR ANY RUNOFF ISSUES MAY  
BE THE FLORIDA PENINSULA AND THE WESTERN GULF COAST.  
 
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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