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   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   
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   AWUS01 KWNH 261035   
   FFGMPD   
   CAZ000-262000-   
      
   Mesoscale Precipitation Discussion 1280   
   NWS Weather Prediction Center College Park MD   
   535 AM EST Fri Dec 26 2025   
      
   Areas affected...Transverse Ranges to southern CA coast   
      
   Concerning...Heavy rainfall...Flash flooding likely   
      
   Valid 261034Z - 262000Z   
      
   SUMMARY...Areas of flash flooding will continue to affect portions   
   of the Transverse Ranges to the coast overnight into the late   
   morning hours. Hourly rainfall values of 0.5 to 1.0 inches   
   (locally higher) are likely which will maintain concerns for   
   impacts including landslides/debris flows and urban flooding.   
      
   DISCUSSION...1015Z radar imagery combined with local mesonet and   
   personal weather observations out of southern CA continued to show   
   areas of heavy rain within a narrow axis from the offshore waters   
   into mainly Ventura County. Hourly rainfall over 1 inch has been   
   observed in Ventura County with 3-hour totals of 1 to 2+ inches.   
   Local Wunderground gauges showed a couple of 30 minute rainfall   
   values over 0.5 inches within the past 2-3 hours near Ojai. These   
   rains were associated with a slow moving low level convergence   
   axis (remnant frontal boundary) that was oriented SSW to NNE   
   across Ventura County with PW values of 1.0 to 1.2 inches along   
   the coast and SSW 850-700 mb winds of 25-35 kt. Enhanced   
   divergence aloft may also be contributing to increased rainfall   
   intensity over the region, within the right-entrance region of a   
   150 kt jet streak aloft located over the Sierra Nevada.   
      
   Short term forecasts from the RAP show the low level convergence   
   axis and localized max in IVT values (up to 500 kg/m/s) slowly   
   advancing eastward over the next 6-9 hours. The result will be   
   localized high rain rates into the terrain, slowly shifting east,   
   given the favorable orthogonal orientation of the low level winds   
   to the axis of terrain. Hourly rainfall of 0.5 to 1.0+ inches   
   should advance eastward from Ventura County into Los Angeles   
   County through 15Z, possibly clearing Los Angeles County after   
   roughly 17Z. While the greatest potential for these higher rates   
   will be in the upslope favored terrain, shallow/weak instability   
   up to ~250 J/kg and short term training could support 0.5+ inch   
   hourly rainfall into the lower elevation urban areas as well.   
   Additional rainfall of 1 to 3 inches will be possible through 20Z   
   with potential for higher impact localized flash flooding over   
   sensitive burn scar locations in and around the Los Angeles metro.   
   Given heavy rain over the past 2 days, many locations contain   
   saturated soils with additional rainfall likely translating   
   directly into runoff. With this rainfall, there will be the   
   potential for dangerous travel and life-threatening impacts from   
   flooding.   
      
   Otto   
      
   ...Please see https://urldefense.com/v3/__http://www.wpc.ncep.noaa.gov__;!!=   
   DZ3fjg!-LZMtVUrN3iB_BZn50erNlgWuVFx2Gz-S7kpwOFNwFuPHWglkqMScRyfzLUyJeQPHOuE=   
   N6Uq6vXg3BsEMf321O9Vt3M$  for graphic product...   
      
   ATTN...WFO...HNX...LOX...SGX...   
      
   ATTN...RFC...RSA...NWC...   
      
   LAT...LON   34811863 34471778 34201694 33671672 33361764=20   
               33471824 33761916 34071955 34451952 34761922=20   
   =20=20=20=20=20=20=20=20=20=20=20=20   
      
   =3D =3D =3D   
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