Does in like a lamb, always mean out like a lion?

By Rod Hill on 2015-03-09

With a sunny warm weekend forecast, it is safe to say March has started like a lamb! According to weather folklore, a "lamb" beginning always leads to a roaring lion finish as April approaches. If true, this piece of weather savvy knowledge would mean chilly wet days for the Northwest are just 2-3 weeks away. Below, I examine the truth behind the common belief.

Going back 15 years to the March of 2000, Portland has started March one way and finished the opposite 10 times. Of those 10 years, March came in like a lamb and went out like a lion 5 times and did the opposite an equal number. In other words, history tells us this March has a two in three chance of ending wet as a roaring lion!

Looking in the record book, March 2005 seems to match this month's warm start the best. The first ten days of the month that year hit 60 degrees or better 6 days and warmed into the 70s three times! The last 6 days of March 2005 saw nearly 3.00 inches of rain fall with highs mostly in the low to mid 50s.

If we use March of 2005 as a clue to predict this spring and summer, here are the results. March of 2005 was in the middle of three consecutive neutral seasons, meaning no La Nina or El Nino.  Although this winter is a borderline weak El Nino pattern for the Northwest, it can be argued that we are in the 3rd year of near neutral conditions.  I say this, to give some positive weight to a March 2005 comparison.  

The spring of 2005 did go on to see above normal rainfall.  In fact, May of that year was the 5th wettest on record at PDX.  But, the summer months of July, August and September saw beautiful northwest weather.  Only 14 days saw high temperatures of 90 degrees and no days reached 100.  (Far more comfortable than the 21- 90 degree days we experienced last summer.)  Better than half of all summer days back in 2005 saw sunny skies from start to finish. 

In conclusion, the record book shows a good chance of rainy days to finish the month. However, current forecast outlooks show this year could be an exception, meaning drier and warmer than normal weather could continue into April.  The final point is that history shows this summer could be nice and comfortable.  Meaning today's warm air may not be a sign of hot days to come. 

Meteorologist Rod Hill    (March 6, 2015)