Tuesday, July 22, 2014

Another cold front, then another BIGGER cold front!

It's rare to talk about cold fronts in July as much as we have been this month. All these fronts, Canadian air intrusions, and upper-level lows have contributed to a month that is averaging over 5 degrees below normal and the third coolest July in Memphis recorded history through yesterday. Well, we have a couple more fronts that will contribute to what will very likely end up keeping temps well below normal for the month by the time it ends.

Top 10 Coolest Julys in Memphis since 1875 (2014 through July 21) by average monthly temp.

A "typical" July front (if they make it this far south) is one that sinks into the area and weakens, then washes out with little effect other than perhaps a wind shift. The first front in our 7-day forecast arrives Wednesday night and is a little stronger than typical, but not like what we saw last week. It'll bring a chance of thunderstorms Wednesday and Wednesday night, then shift wind to the north and drop dewpoints (a measure of humidity) back down to near 60 briefly. Temps will also fall back into the mid 80s on Thursday. However, like a typical post-frontal airmass in July, it won't last long. Heat and humidity build heading into the weekend.

Location of surface fronts on Wednesday evening, along with where rain chances are expected via the NWS. The front will turn around and move back north by Friday.

By late in the weekend into Monday, we'll see scattered storms popping back up over the area as another front moves closer. Looking at the airmass pushing in behind this front, it looks like well below normal temperatures are again expected for a good part of next week. We're not forecasting anything like the records we had last week at this point, but those who could live without Memphis heat and humidity will likely get yet another multi-day period of relief. Can one even call it relief when it's been the norm this summer it seems??

Temperature outlook for July 27-31, indicating a high likelihood of below normal temps for a large portion of the eastern U.S. due to a significant upper-level trough expected to dominate the weather pattern. 

On a separate note, today is the 11 year anniversary of the derecho (long-lived wind storm) that swept through the city on July 22, 2003 (dubbed "Hurricane Elvis"). Read our retrospective written last year for the 10-year anniversary here.

Erik Proseus
MWN Meteorologist

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