TZUTC: 0000   
   MSGID: 167605.weather@1:2320/105 2da6385a   
   PID: Synchronet 3.21a-Linux master/123f2d28a Jul 12 2025 GCC 12.2.0   
   TID: SBBSecho 3.28-Linux master/123f2d28a Jul 12 2025 GCC 12.2.0   
   BBSID: CAPCITY2   
   CHRS: ASCII 1   
   FORMAT: flowed   
   FOUS30 KWBC 140821   
   QPFERD   
      
   Excessive Rainfall Discussion   
   NWS Weather Prediction Center College Park MD   
   321 AM EST Sun Dec 14 2025   
      
   Day 1   
   Valid 12Z Sun Dec 14 2025 - 12Z Mon Dec 15 2025   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL OVER A PORTION OF   
   WESTERN WASHINGTON...   
      
   Maintained the Marginal Risk area over parts of the Olympic and   
   northern Cascade Ranges in Washington as the next real push of=20   
   moisture approaches later tonight into the early morning hours of=20   
   Monday. Any rainfall in Washington before then should be light and   
   on the periphery of a rain area directed on-shore north of the=20   
   international border. By 15/00Z...precipitable water values should   
   be approaching 1 inch along the coast as 850 mb winds approach the   
   Washington/Oregon coast. Initially the 850 mb winds should have=20   
   more of a southerly than a westerly component...but eventually they   
   do take on a more orthogonal component to the Washington coast=20   
   ranges and Olympics. That is when the best chance for any excessive   
   rainfall is expected. Model guidance remains in the 0.5 to 0.75=20   
   inch range with locally 1.5 inches of precipitation focused in the=20   
   terrain. While these amounts are pretty modest for this part of the   
   country...the area remains hydrologically sensitive given the=20   
   recent heavy to excessive rainfall event from earlier in the week=20   
   and even this amount of rainfall could result in renewed hydrologic   
   concerns.=20   
      
   Bann   
      
   Day 2   
   Valid 12Z Mon Dec 15 2025 - 12Z Tue Dec 16 2025   
      
   ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL OVER WESTERN   
   WASHINGTON AND NORTHWEST OREGON...   
      
   Areal coverage of rainfall expands and rain rates increase on=20   
   Monday as a well defined atmospheric river continues to direct=20   
   abundant moisture into the Washington coastal ranges and Cascades.   
   IVT values approaching 800 is currently forecast along or near the   
   Washington coast as the Day 2 period begins...then weakens=20   
   somewhat as the axis progresses southward into Oregon. Given=20   
   antecedent conditions from the excessive rainfall event from=20   
   earlier in the week plus whatever falls on in the Day 1=20   
   period...the concern is for renewed flooding potential in addition=20   
   to worsening any on- going flooding. Given how water-logged the=20   
   soils have been...the potential is there for additional landslides=20   
   or mudslides. Saw little reason to modify the Slight risk area too=20   
   much...but continued the idea from yesterday in shrinking the=20   
   Slight risk area to minimize the overlap with heavy snow areas=20   
   (especially in the northern part of the Cascades as depicted by the   
   WPC Winter Weather desk). That being said...the overall forecast=20   
   reasoning changed little given the consistent magnitude of the=20   
   IVT/precipitable water values and QPF forecast by the global=20   
   models. The focus of the heavy rainfall should gradually shift=20   
   southward into an area that did not receive as much rainfall from=20   
   the previous atmospheric river.=20   
      
   Introduced a Marginal Risk area mainly focused over the Idaho   
   panhandle and a small portion of neighboring eastern Washington   
   mainly for later in the period. The Atmospheric River moisture   
   plume will be spreading increasing amounts of moisture into the   
   eastern part of Washington and northern Idaho. Deterministic QPF   
   approaching an inch is forecast for areas that had hydrologic   
   problems recently and concern is for additional problems.=20   
      
   Bann   
      
   Day 3   
   Valid 12Z Tue Dec 16 2025 - 12Z Wed Dec 17 2025   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL LINGERING OVER   
   PARTS OF THE PACIFIC NORTHWEST INTO FAR NORTHWEST CALIFORNIA...   
      
   Precipitation lingers from Washington southward along the Cascades   
   and the coastal ranges into northwest California on Tuesday and   
   into the early morning hours on Wednesday. With much of that   
   falling post-frontal and the heavier precipitation amounts falling   
   in the form of snow in the northern Cascades...will maintain the   
   Marginal Risk area for the time. Once again the main adjustments to   
   the outlook areas were to limit the overlap of excessive rainfall   
   with heavy areas mainly in Washington. The complex terrain of   
   northern Idaho and northwest MT made it difficult to avoid   
   overlapping but the idea is for any excessive rainfall to occur at   
   lower elevation locations in light of lowering thickness vales/snow   
   levels.=20=20   
      
   Bann   
      
      
   Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/94epoints.txt__;!!DZ3fjg!67FMVwnM5PvBODTKoXt6tbq3YpsrpP4EDgqvdGgk26DD=   
   Ol9SNODmDi-Afe8vOR-C5hTSnRwIqxM1R0oYQnJNGq-LOts$=20   
   Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/98epoints.txt__;!!DZ3fjg!67FMVwnM5PvBODTKoXt6tbq3YpsrpP4EDgqvdGgk26DD=   
   Ol9SNODmDi-Afe8vOR-C5hTSnRwIqxM1R0oYQnJNRIw89_I$=20   
   Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/99epoints.txt__;!!DZ3fjg!67FMVwnM5PvBODTKoXt6tbq3YpsrpP4EDgqvdGgk26DD=   
   Ol9SNODmDi-Afe8vOR-C5hTSnRwIqxM1R0oYQnJNbaexLBg$=20   
      
   =3D =3D =3D   
   To unsubscribe from WX-STORM and you already have a login, go to   
   https://lists.illinois.edu and use the "Unsubscribe" link.  Otherwise email   
   Chris Novy at cnovy@cox.net and ask to be removed from WX-STORM.   
      
   --- SBBSecho 3.28-Linux   
    * Origin: Capitol City Online (1:2320/105)   
   SEEN-BY: 19/10 104/119 105/81 106/201 114/10 120/302 128/187 129/14   
   SEEN-BY: 153/757 7715 154/10 30 50 110 700 218/700 840 220/10 20 30   
   SEEN-BY: 220/70 90 221/1 6 360 226/17 18 30 44 50 227/114 229/110   
   SEEN-BY: 229/134 206 300 307 317 400 426 428 470 664 700 705 266/512   
   SEEN-BY: 267/800 291/111 301/1 320/219 322/757 335/364 341/66 342/200   
   SEEN-BY: 396/45 460/58 633/280 712/848 770/1 100 340 350 772/210 220   
   SEEN-BY: 772/230 902/26 2320/0 105 304 3634/12 5020/400 5075/35   
   PATH: 2320/105 154/10 221/6 218/840 770/1 633/280 229/426