Analogues and Guidance Indicate a Warmer and Somewhat Drier May In Store for Southeast Lower Michigan

Thus far, the current spring pattern has evolved as indicated by both analogues and recent guidance. A colder than normal March evolved into a near normal to above in April as temperature patterns projected and in actuality; transitioned from below normal to above. The timing of the pattern change has been somewhat ahead of the timing of both spring analogues and models by about a week or two week. But, I'm not complaining after last winter and early spring with spring development, now in full force.

Spring analogues for May called for a near normal May temperature-wise while latest guidance indicates above normal temperatures. With out timing of pattern changes seemingly ahead of past analogues, above normal temperatures are the best forecast. Typically May's average high temperatures start out in the mid 60s and warm to the mid 70s by the close. Overnight lows begin the month in the mid 40s and rise to the mid 50s by the close. Why there is still the risk of a frost or freeze, none looks likely in the next week to 10 days anyway and there's less than a 30% chance through the month with the above normal temperatures. I'll keep the blog updated if the risk does arise if colder air masses make their way out of Canada.

Drier than normal or average spring conditions were projected by both the analogues and models, and continue to be upheld by latest precipitation guidance for May. Local analogues projected Spring rainfall would average at least an inch or two below normal across all of Southeast Lower Michigan. Thus far this spring through the end of April, precipitation has averaged around two inches below normal. Latest model projections continue the drier than average pattern with below normal rainfall. Note the CFSv2 is calling for a notable bull-eye of below normal rainfall to our south, over the Ohio Valley. Interesting since this is the area that has been most active with precipitation the past several seasons on average. May is generally one of our wetter months with around three inches of rain usually falling - therefore this dry pattern established bares watching for the growing season.

Making weather fun while we all learn,
Bill Deedler -SEMI_WeatherHistorian