IOP#4 Over; IOP#5 Starts Tomorrow
Weather Status: Only light snow this morning at BLU with another 0.44 inches since yesterday. This brought the estimated total precipitation to 7 to 8 inches in the ARB...a great event. A new fast moving wave due to start impacting the ARB tomorrow will bring a bit more than an inch over a 12-18 hour period on Tuesday. This wave was still tapping a tropical IPW plume, but the speed of the wave was reducing the expected total precipitation. Rain looks like it will begin Tuesday early morning ( 8 Jan 12UTC), the the heaviest period from 8/21 to 9/02UTC (8/13L to 18L). Coarser grid models were predicting a little over an inch with higher resolution models between 1 and 2 inches. HMT models averaged about 1.5 inches. The wave certainly fits within the IOP criteria and we offically declare IOP#5 underway tomorrow (8 Jan 12UTC [04L]). A second wave moving in Wed night into Thurs, looked a lot weaker in the NWP products than yesterday. Most of the dynamics associated with storm look to be moving further north and hence precipitation predicted is below IOP criteria. We will look at this storms potential tomorrow to see if it has better IOP possibilities. Beyond this wave a ridge building over the west coast will keep activity to a minimum at least through the next 10 days.
Summary: IOP#5 starts 8 Jan 12UTC (04L); precipitation ending 9 Jan 06UTC (22L). Second wave will arrive late Wed/Thurs but is likely to be weak. No activity for an extended period beyond that.
Observational Status: Profiler sites at Chico and Cazadero are out due to power failure. Severe damage to powerlines will keep these sites out of action for another few days. BLU power is still out at the surface site but the observation at the airport was back on line today. Radar crew will deploy to radar and prepare site for IOP#5. A decision about establishing generator power to bring back the HMT instrumentation will be made later today after assessment by the radar crew. For IOP#5 sounding operations will commence Tuesday morning (8 Jan 12UTC [04L]) with the final sonde at 9 Jan 03UTC (8/19L). Radar will be operational from Tuesday morning through Tuesday night.
Decision summary: IOP#5 Radar and RAOB operations will begin at 8 Jan 12UTC (04L). Sondes will be every 3 hours ending with the release on 9 Jan 03UTC (8/19L). Radar operations will terminate 9 Jan 06UTC (8/22L).
Product Status: Other than the sites without power products were available; all HMT model products were available on the web.