Thursday, June 12, 2014

Rainfall recap, one more storm chance, and a lunar rarity

It's been a wet couple of weeks in the Mid-South! The proverbial ark jokes had started, but seemed to be quelled a bit by the beauty in the skies Monday and Tuesday evenings as gorgeous rainbows graced the horizon and sunsets were spectacular both nights!

Photo taken Monday night in Shelby Forest by photog Brian Anderson.

The rain stats for the recent fortnight are, if not surprising, still pretty amazing. At Memphis International Airport, since May 27, 15 of the 16 days have had precipitation fall in some amount with 12 days of measurable rain totaling 5.47"! Even more jaw-dropping are the totals from west TN outside the metro over to the western outskirts of Nashville. The graphic below shows "departure from normal" precip totals for the past 14 days. Notice that while the metro was anywhere from 1-4" above normal for that period, parts of the Tennessee River Valley were 8"+ above normal! (Not 8" of rain, but ABOVE NORMAL - which is in the 2" range.)

We will have one more shot at rain tonight as a weak cold front moves through the area. The main energy with this system, provided by upper-level support, will be southwest of the metro, across southern AR, east TX, and northern Louisiana. Clusters of thunderstorms across these areas will likely form into a squall line and move east into the Lower Mississippi River Valley. Due to the possibility of severe storms, a Slight Risk of severe weather covers these areas and extends to just southwest of Memphis (as shown below).

While I don't expect severe storms in the metro, thunder is a definite possibility with scattered storms possible after 7pm tonight. If you have evening ball games, the later they go, the more likely lightning and thunder will be in the area. Higher rain and thunder chances will exist from about 10pm through the wee hours Friday morning. By Friday morning rush hour, most all of the precipitation will be gone, but a few lingering showers will be possible through Friday morning.

Tonight's event will probably be the last chance of rain in the metro for a number of days as summertime high pressure builds in and causes temperatures to rise to 90+ by the end of the weekend. This pattern will carry us into next week before small thunderstorm chances re-emerge by the middle of the week. I hope you're ready for some more typical Memphis summer weather! (Click here for the complete MWN Forecast.)

Friday the 13th Full Moon

One final note on a phenomena that has been making the rounds on social and traditional media: Tomorrow is the only "Friday the 13th" of 2014. Coincidentally, for some, it is also a full moon! Why do I say "for some?" While most outlets tout the full moon on Friday the 13th and note its historical significance (first occurrence since 2000 and it won't happen again until 2049), they fail to provide full detail. A full moon is actually not a day-long phenomena, it occurs at a particular minute. Tonight, the full moon occurs at 12:13am EDT - which is on Friday. So for those in Eastern Time, it is indeed a full moon on Friday the 13th. For those of us west of  Eastern Time (Central, Mountain, Pacific Time), the full moon actually occurs before midnight - 11:12pm CDT in Memphis to be exact. (This article on Vox has a good description of the event and the reason it's so rare.) So while we will TECHNICALLY miss out on this double harbinger of bad luck (who's complaining?), I wouldn't blame you for going along with the story and calling tonight's full moon a Friday the 13th lunar event. Too bad it'll be cloudy and you won't see it anyway...

Erik Proseus
MWN Meteorologist

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