LESSONS LEARNED

An important lesson I learned is that I must modify my forecast to account for local effects at a specific site.  This is especially true at Quillayute which lies only three miles from the Pacific Ocean.  The image below of sea surface temperatures shows 11 degree C (52 F) water temperatures off the coast of Quillayute.  Because I didn't take into account the possibility of the front slowing down from more closely examining the 700-mb image on the previous page, I thought drier air would be moving into the area; however, as these METARS show, the wind direction didn't change until after the 06Z November 13 deadline which delivered the cooler, drier air later than I expected.  With the wind bringing in mild air off the Pacific Ocean waters, there was no change in the dew point, with it staying near 50 degrees.  As you remember, the dew point was predicted by the SREF to fall to the mid 40's.


This is an image of sea surface temperatures from November 14, 2008 that shows the water temperature off the coast of Quillayute at 11 degrees C (52 F), courtesy of CoolWx.

Another look at these MOS tables continue to tell the story why the temperature didn't drop the way I planned.  Not only do they show the wind still blowing out of the west at 06Z November 13, they show the cloud ceilings would be quite low, as well.  The GFS and NGM show the ceilings down as low as 1,000 feet or less, while the ETA shows the cloud ceilings much higher at 3,100 to 6,500 feet which helps explain why its predicted temperature was lower.  These METARS show the actual cloud ceilings were only a couple thousand feet or less most of the time on the evening of November 12.  MOS typically forecasts nighttime low temperatures too cool when there's low cloud cover which is exactly what happened.  This is another reason why the temperature stayed in the 50's until after 06Z November 13.  So, there were a couple indications that should've told me to forecast on the high side of MOS for that evening.

As you can imagine, Quillayute's proximity to the Pacific Ocean has a huge impact on its weather and this is only one small example. You can see, I'm still making mistakes as the WxChallenge continues; however, the more mistakes I make, the more I'll continue to learn from them and hopefully become a better weather forecaster.


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