# Friday, March 16, 2012
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WRF Ensemble Precipitation Forecast from 03/16/12 12z Click
BUFKIT Display of WRF Precipitation Forecast
03/16/12 12z

Updated 03/29/12. Edited to correct the date for the most rainfall in a day this season (through March 16) at Los Angeles.

It's been a bleak rain season. So far the most rainfall Los Angeles has recorded in a day this season was in the record-setting early season storm October 5, when Downtown recorded 1.15 inch of rain. As of today Los Angeles' water year rainfall total stands at a meager 41% of normal.

If current forecasts verify, the rainfall total at Los Angeles for this weekend's storm might exceed last October's storm. Maybe. BUFKIT display of WRF ensemble precipitation forecast shows a spread from 0.4 inch to about 1.1 inch at LAX, and from about 0.65 inch to 1.6 inch at Van Nuys. The 18z WRF/NAM run was wetter than the 12z run producing about 0.95 inch at LAX and 1.1 inch at Van Nuys. A strong southwesterly inflow of around 35-40 kts is forecast and could produce higher precipitation amounts on foothill and mountain slopes which have a southerly to westerly aspect.

The Los Angeles Marathon is this Sunday, and after last year's record-setting Marathon day rainfall, many are wondering about the weather on Sunday. Last year of 19,798 runners that completed the race, more than 10,000 were on the course for longer than 5 hours and nearly 2000 were out there for longer than 7 hours. The Elite Men and most of the runners start at 7:24 am, so the majority of runners will finish after noon.

Check with the NWS for the latest official information, but as it looks now the bulk of the rain is forecast to occur on Saturday and the Marathon will be run after the cold front has passed through the area. This is a different weather scenario than last year, but one that can produce cold, showery, blustery conditions with strong winds out of the northwest. In the unstable conditions that typically follow a cold front heavy showers, gusty winds and even a thunderstorm are possible. The HPC 6-Hour Probabilistic Precipitation Guidance for the periods ending 10:00 am Sunday morning and 4:00 pm Sunday afternoon indicate a high probability of at least 0.01 inch of rain in the Los Angeles area. We'll see!

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