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Storm Tracking Across the Plains; Powerful Pacific System is Approaching

Some heavy rain and possible flash flooding may affect the Central Plains through Thursday. Meanwhile, wintry weather conditions will spread through portions of Central and Northern Plains. A powerful storm system is forecast to approach the Pacific Northwest, then spreading inland and down through California through the end of this week. A series of storms will impact Alaska into the weekend. Read More >

 

Overview - Record low pressure storm kicks Wet Season into high gear

 

 

 

After a prolonged period of dry weather for much of the region, the first storm system of the 2019-2020 wet season came in with authority. A bomb cyclone developed off the Pacific Northwest Coast ultimately moving eastward bringing wild weather to much of southern Oregon and California November 26 through November 28.  For historical context it be noted that prior to the stormy weather Fire Weather conditions were of concern with dry and gusty offshore flow winds in California.  A few fires broke out with the most notable one being the Cave Fire near Santa Barbara. 

 

Composed by: MMehle

Historic low pressure

The OR/CA storm peaked pressure-wise with a central pressure of 970 hPa/28.64" at 7 pm PST before slowly weakening.
@NWSWPC

 

Rapid cyclogenesis, development/strengthening of a low pressure,  occurred off the California/Oregon coast. In fact, the development was so strong that it was called a Bomb Cyclone or Bombogensis.  In other words, the pressure drop was high enough in less than 24 hours to meet criteria. Automated sensors over the ocean and on land recorded the pressure drop nicely.  

Satellite loop

Satellite loop showing the rapid intensification of the surface low pressure. 

Storm Prediction Outlook

Rope cloud showing the potent cold front.

Pressure traceImpressive pressure drop being noted on a Buoy off the NorCal Coast.  Image from @NWSEureka

 

Numerical weather prediction models suggested a potent cold front as the storm system came inland.  One of the biggest impacts were intense rainfall rates that could trigger a debris flow in the Kincade Burn Area.  Therefore, a Flash Flood Watch was issued before the predicted frontal passage.  Fortunately, the cold front didn't intensify until it was through the burn area and no debris flows occurred. The intense cold front did develop and brought urban flooding 

Flash Flood WatchConcern for intense rainfall triggering a debris flow

Radar loop

Radar Loop Tuesday evening November 26. As the potent cold front swept through rainfall rates increased resulting in minor flooding. 

Snow LevelLowering snow levels behind the front.

 

Snow covering the higher peaks in the Bay Area is not all that uncommon during the month of November and this storm system did result in high elevation snow.  Snow levels wavered through midday November 26, but once the moisture arrived snow levels were low enough for snow.  Snow capped mountains along the Big Sur Coast is always magical with the juxtaposition between the blue Pacific and snowy mountain peaks.  Snow was observed all the way down to approximately 2,000 feet.

Winter Weather AdvisoryWinter Weather Advisory issued for the mountains above Big Sur

Snow over the Santa Lucia Mountains 1

Snow covering the Santa Lucia Mountains. Picture: L. Pantilat

Snow over the Santa Lucia MountainsSnow covering the Santa Lucia Mountains. Picture: L. Pantilat