Spring is closer than you think

Spring has sprung early this year in parts of the USA.

According to the National Phenology Network spring leaf out is running 20 days early across the Ohio Valley. Spring is running 5-6 weeks early in parts of the Southwest. Interestingly, the spring debut is running a few days later than average across the Gulf Coast.

National Phenology Network.

HOW DOES THIS SPRING COMPARE TO “NORMAL”?

Spring continues to arrive early in the west and late in the east, compared to a long-term average (1981-2010). Spring is four weeks early in southern Utah and eastern Washington and 5-6 weeks early in the Grand Canyon. Spring is a few days late in Birmingham, AL, and Charleston, SC.

The timing of leaf-out, migration, flowering and other seasonal phenomena in many species is closely tied to local weather conditions and broad climatic patterns. The Spring Index maps offered by USA-NPN shed light on plant and animal phenology, based on local weather and climate conditions.

Not all roses

Spring’s early arrival is not necessarily good news for plants.

Angela Fritz at The Washington Post’s Capital Weather Gang elaborates.

This is not surprising. In fact, it is exactly what we should expect as the climate warms, according to myriad peer-reviewed studies summarized succinctly by the 2017 National Climate Assessment. In technical terms, the growing season in North America is getting longer. You may also see it referred to as “frost-free” days, since the growing season is the span of time between the last frost and the first frost.

Just ask any citrus grower in the Southeast — a late frost or freeze can wipe out an entire crop, depending on the timing. Once plants have reached a certain phase of development, which happens earlier when winter is warm and spring is early, they are extremely fragile and susceptible to freezing temperatures. If, say, half of the plant’s blossoms are killed off by a freeze, it essentially cuts the plant’s productivity by half.

Minnesota mild

Temperatures soared into the 40s and even a few 50s across southern Minnesota Tuesday. A slight cool front arrives Wednesday. But temperatures return to the 40s next weekend.

NOAA via Weather Bell.

Sunday rain?

The latest model trends favor mostly rain for southern Minnesota Sunday, with snow chances up north. Rain may change to snow behind the system Monday. It’s still early and this could change. Here’s NOAA’s GFS model.

NOAA GFS Sunday into Monday via tropical tidbits.

Stay tuned and watch the refreeze out there.