TZUTC: 0000   
   MSGID: 167758.weather@1:2320/105 2dacd24c   
   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 190829   
   QPFERD   
      
   Excessive Rainfall Discussion   
   NWS Weather Prediction Center College Park MD   
   329 AM EST Fri Dec 19 2025   
      
   Day 1   
   Valid 12Z Fri Dec 19 2025 - 12Z Sat Dec 20 2025   
      
   ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL MAINLY OVER   
   PORTIONS OF NORTHWEST CALIFORNIA...   
      
   ...Pacific Northwest...   
      
   Ongoing atmospheric river will drift southward while swift flow   
   aloft transports the plume of deep layer moisture into parts of=20   
   the northern Great Basin. IVT values at or above 700 units are=20   
   forecast to cover much of Oregon initially before it weakens as=20   
   the axis of the moisture plume and associated precipitation settles   
   into northern California. The Marginal Risk was maintained for   
   southwest Oregon and northern California, as well as the Slight   
   Risk over northwest California. Minimal adjustments were made to   
   account for the latest QPF trends and WPC forecast.   
      
   ...Southern New England...   
      
   Locally heavy rainfall will be possible for portions of the   
   Northeast during this period as moisture drawn northward encounters   
   the advancing trough over the eastern states. With time the   
   the moist flow aloft becomes increasingly diffluent and a surface=20   
   warm front approaches from the south early on Friday. WPC=20   
   Deterministic QPF in the 1.0 to 1.4 inch range is forecast along=20   
   the track of the low. Offsetting the potential of excessive=20   
   rainfall by limiting rainfall rates/amount is the meager=20   
   instability expected to be in place. A Marginal Risk was maintained   
   from the New York/Connecticut/Massachusetts border to downeast=20   
   Maine.   
      
   Campbell/Bann   
      
      
   Day 2   
   Valid 12Z Sat Dec 20 2025 - 12Z Sun Dec 21 2025   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL IN PORTIONS OF=20   
   NORTHERN CALIFORNIA|...   
      
   A relative lull in moisture surges expected during the majority of   
   this period before the next stronger atmospheric river from the=20   
   Pacific reaches northern California towards the end of Day 2.   
   Although there may be some overlap in heavy rainfall, the axis of=20   
   the strongest on-shore winds and the greatest on-shore moisture=20   
   transport looks to be south of the axis of the previous event.   
      
   Precipitable water values increase to between 1.2 and 1.4 inches=20   
   along the northern California coast north of San Francisco south of   
   the Oregon/California border by early Saturday evening. Given such   
   high snow levels...there is not a lot of concern about=20   
   precipitation type until the moisture laden flow reaches the=20   
   northern end of the Sierra Nevada range (save for a few mountain=20   
   tops along the trajectory inland from the coast). The urban centers   
   between Sacramento to San Francisco will be more at play this=20   
   period lead   
      
   Campbell/Bann   
      
      
   Day 3   
   Valid 12Z Sun Dec 21 2025 - 12Z Mon Dec 22 2025   
      
   ...THERE IS A SLIGHT RISK FOR EXCESSIVE RAINFALL IN EFFECT FOR   
   NORTHERN CALIFORNIA...   
      
   The Atmospheric River will strengthen over the northern half of   
   California resulting in scattered to widespread areas of enhanced   
   rainfall overlapping much of the same footprint from the Day 2   
   period. The latest guidance is suggesting daily accumulations of 3   
   to 7 inches, with 48 hour totals nearing 5 to 9 inches. A Slight=20   
   Risk is in effect from the West Coast to much of the Sierra Nevada=20   
   Range. There may be a need for an upgrade for portions of the=20   
   Sierra Nevada should guidance continue to increase over this area.   
      
   Campbell   
      
      
   Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/94epoints.txt__;!!DZ3fjg!63RNlJrYHmP3f7jP6XgvTdkqtm--4VWdNt_PWmJhN8Lt=   
   ZjO1fZAJtb7fY_QzfvUsJfJxk4pPUFgv4LdICm2fCSKtfsk$=20   
   Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/98epoints.txt__;!!DZ3fjg!63RNlJrYHmP3f7jP6XgvTdkqtm--4VWdNt_PWmJhN8Lt=   
   ZjO1fZAJtb7fY_QzfvUsJfJxk4pPUFgv4LdICm2fKlJ7JEY$=20   
   Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/99epoints.txt__;!!DZ3fjg!63RNlJrYHmP3f7jP6XgvTdkqtm--4VWdNt_PWmJhN8Lt=   
   ZjO1fZAJtb7fY_QzfvUsJfJxk4pPUFgv4LdICm2ftX0Ce9k$=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