TZUTC: 0000   
   MSGID: 168248.weather@1:2320/105 2dc254b3   
   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 041555   
   QPFERD   
      
   Excessive Rainfall Discussion   
   NWS Weather Prediction Center College Park MD   
   1055 AM EST Sun Jan 4 2026   
      
   Day 1   
   Valid 16Z Sun Jan 04 2026 - 12Z Mon Jan 05 2026   
      
   ...THERE IS A SLIGHT RISK OF EXCESSIVE RAINFALL FOR PORTIONS OF THE   
   SIERRA AND FOOTHILLS...   
      
   16z Update: Locally heavy rainfall rates into coastal Monterey=20   
   County will continue to result in an isolated flash flood and=20   
   mudslide risk through ~00z. Hourly rainfall between 0.5"-1" will=20   
   continue to locally occur, with a slow southward shift expected in   
   these heavier rainfall rates through the day. Rainfall totals of=20   
   2-4" are expected along the coastal portion of Monterey County.   
      
   Another focus for heavy rainfall will be across the eastern valley   
   into the foothills of the central Sierra. Southerly flow up the   
   valley, combined with westerly flow behind an approaching cold=20   
   front, will locally enhance convergence and support some periodic=20   
   low topped convection capable of rainfall rates over 0.5"/hr. The=20   
   combination of upslope enhanced rainfall and these locally higher=20   
   rates will result in a continued isolated to scattered flash flood=20   
   risk through today.   
      
   Showers into southern CA through today may periodically drop ~0.5"   
   of rain within an hour...but the coverage and magnitude of rainfall   
   is not expected to match what occurred yesterday over Santa=20   
   Barbara and Ventura counties. By tonight the approaching cold=20   
   front should increase shower coverage, but again hourly rainfall=20   
   should generally peak around 0.5" or less. HREF FFG exceedance=20   
   probabilities stay below 15%, and while there is a risk of=20   
   isolated flash flooding and mudslides, the magnitude of the threat   
   is lower than yesterday and also mainly focused farther south.   
      
   Chenard   
      
   ...Previous Discussion...   
      
   Precipitation is expected to increase in coverage and intensity   
   Sunday morning across northern to central California as the next   
   batch of shortwave energy rotates through the mean west coast trof   
   and inland across central CA. PW values and 850-700 mb moisture   
   flux are expected to increase Sunday associated with this next   
   batch of shortwave energy. This will support locally heavy precip   
   totals along much of the California coast Ranges and into the   
   upslope of the Sierra. Hourly rainfall rates in the .25-.50" range   
   possible along the central CA coast and into the upslope of the   
   northern Sierra. A small slight risk area was maintained in the   
   upslope of the northern Sierra where model consensus is for   
   potential of additional 1 to 2" of rain. The HREF probabilities of   
   3 hr precip exceeding 3 hr FFG values shows an area of 15-30%   
   probabilities sinking southward along the upslope of the northern   
   Sierra Sunday where the slight risk area is drawn. Overall, no   
   changes of note made to the previous outlook for the upcoming day 1   
   period.   
      
      
   Oravec   
      
   Day 2   
   Valid 12Z Mon Jan 05 2026 - 12Z Tue Jan 06 2026   
      
   ...THERE IS A MARGINAL RISK OF EXCESSIVE RAINFALL ALONG THE CENTRAL   
   TO NORTHERN CALIFORNIA COAST AND NORTHERN CALIFORNIA...   
      
      
   There are large scale differences developing day 2 with the   
   amplification of a closed low in the base of the mean trof off the   
   Central to Southern CA coast. The NAM and GFS are showing a more   
   southwest solution compared to the EC, CMC and UKMET. This farther   
   southwest solution is resulting in a trend of less precip along   
   the central CA coast to the south of San Francisco and into the   
   Northern Sierra in the GFS and NAM as the low level flow has a   
   much weaker onshore component compared to the EC, CMC and UKMET.   
   Models often struggle with closed formation downstream of   
   flattening upper ridges with overall low confidence at the moment.   
   The latest WPC qpf did trend towards less precip across the central   
   CA Coast Range and over the Northern Sierra, but not as dry as the   
   GFS and NAM. Subsequently, the previous marginal risk area was   
   decreased in size. There may be additional changes needed to the   
   risk area with future model cycles, depending how the evolution of   
   the closing off mid to upper level center evolves.   
      
   Oravec   
      
      
   Day 3   
   Valid 12Z Tue Jan 06 2026 - 12Z Wed Jan 07 2026   
      
   ...THE PROBABILITY OF RAINFALL EXCEEDING FLASH FLOOD GUIDANCE IS   
   LESS THAN 5 Percent...   
      
   Oravec   
      
      
   Day 1 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/94epoints.txt__;!!DZ3fjg!80-i9LrAmC3Ks04SpFjmLuL2qFTiJpJSKJU2Qq8T26O7=   
   JXVWNReT2EAIJNXnBsc07wVqNNtPL46TzoEGBVxqvIh4PEI$=20   
   Day 2 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/98epoints.txt__;!!DZ3fjg!80-i9LrAmC3Ks04SpFjmLuL2qFTiJpJSKJU2Qq8T26O7=   
   JXVWNReT2EAIJNXnBsc07wVqNNtPL46TzoEGBVxqZGFxs-I$=20   
   Day 3 threat area: https://urldefense.com/v3/__https://www.wpc.ncep.noaa.go=   
   v/qpf/99epoints.txt__;!!DZ3fjg!80-i9LrAmC3Ks04SpFjmLuL2qFTiJpJSKJU2Qq8T26O7=   
   JXVWNReT2EAIJNXnBsc07wVqNNtPL46TzoEGBVxqu4rp5No$=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: 1/19 100 120 16/0 18/0 19/10 37 105/81 106/201 116/116 123/0   
   SEEN-BY: 123/25 126 130 180 755 3001 3002 4040 128/187 129/14 134/100   
   SEEN-BY: 135/115 142/104 153/143 148 149 151 757 7715 154/10 110 201/0   
   SEEN-BY: 203/0 218/700 840 221/1 6 360 222/2 226/30 227/114 229/110   
   SEEN-BY: 229/134 206 275 300 307 317 400 426 428 470 664 700 705 240/5832   
   SEEN-BY: 250/1 266/512 275/1000 280/5003 291/111 301/1 320/119 219   
   SEEN-BY: 320/319 2119 322/757 762 326/101 335/364 341/66 342/200 396/45   
   SEEN-BY: 423/81 460/58 633/280 712/848 1321 902/26 2320/0 105 304   
   SEEN-BY: 3634/0 12 27 57 58 60 61 119 5020/400 5075/35   
   PATH: 2320/105 3634/12 153/757 221/6 1 320/219 229/426