Heat Wave round 2

The last few summers in Atlanta tended to be humid but not super hot, and there was no shortage of rain as you can see in the maps below. Last week we dealt with the brutal combo of both heat and humidity with hit and miss storms.

By now it’s OLD NEWS that this week will be very hot but not so muggy since I’ve been posting about multi week heat since June 4th-9th. But unlike last week when the high humidity fueled storms the low humidity this week keeps us storm free.

Your soils will lose 1-2″ of water this week if you don’t use the sprinkler. The heat is on through the first weeks of July.

SUMMER AVERAGE TEMPS AND RAINFALL PAST FEW SUMMERS:

Last few summers average rainfall Avoiding drought to say the least

This week as I’ve been saying for many days now we deal with “a dry heat”, air temps as hot or hotter than last week, just less humid. Small favor from mother nature. lol

On the other hand, at least our air conditioners don’t have to WORK AS HARD to cool dry heat compared to moist heat!

And I do think that our Atlanta all-time record high of 106ºF (June 30 2012) is NOT going to fall nor the all-time record high for the state of 112ºF, (July 1952) so there’s that.

LOOKING AHEAD...

REST OF JUNE AND FIRST HALF OF JULY TEMP ANOMALY BASED ON ANALOGS:

Temp anomaly rest of June and first half of July from analogs

END OF JULY AND AUGUST TEMP ANOMALY BASED ON ANALOGS:

Analog based temp anomaly end of July and August

JULY RAINFALL ANOMALY BASED ON ANALOGS:

AUGUST RAIN ANOMALY BASED ON ANALOGS:

CORRELATION BETWEEN AVERAGE JUNE-AUGUST TEMP AND A NEGATIVE GLAAM:

So the combination of La Nina, MJO phases 2-4 and a negative global wind oscillation all point to A GRADUAL SHIFT of the WORST HEAT ANOMALIES to our North and to our West as we move deeper into summer. And the analogs suggest a gradual uptick in scattered thunderstorms as we move further into summer as well.

That doesn’t mean we turn cooler than normal it just means less above-normal than we are getting now. And since average summer temps are still on the rise and the “Dog Days of Summer” are still ahead of us, IF CORRECT, that is much better news than going in the other direction. To put it another way, above-normal heat now is not AS brutal as above-normal heat in the heart of summer since we would start at a higher floor. Long-timers living here can attest to that.

Doesn’t mean this is pleasant now but still a fact.

Of course occasional heat waves this time of year are hardly unprecedented, BUT AT THIS LEVEL they are rare. IN FACT last weeks 99 has never happened that early in history.

THIS WEEK TEMPS MAY REACH LEVELS WITH A “RETURN INTERVAL” OF ONLY ONCE EVERY 10-30 YEARS OR MORE ON AVERAGE IN SOME SPOTS:

850mb (~5K') forecast return interval level (proxy for surface highs) Forecast Temp levels once/10 years to 1/30 years next week NAEFS model

Forecast Heat level return interval 5,000 feet (proxy for surface temps) NAEFS model

ECMWF MODEL SHOWING “RARE AIR” THIS WEEK:

Model is predicting widespread record 850mb temps Compared to historical temp record Euro model is forecasting levels not just at the highest end for this time of year but record levels in many places. NOTE: model bias is too high

HUMIDITY THIS WEEK:

Lower than normal air moisture most of this week Precipitable water = total atmospheric moisture in the air column surface and aloft

5-7 DAY RAINFALL ESTIMATE:

Most of us stay dry the next 5-7 days, at least

Very very rare to have almost no rain chance this time of year, usually heat and humidity are enough to produce SOME LEVEL of chance of pop-up thundershowers even WITHOUT a front or upper-level disturbance.

GFS, ECMWF, AND CMC ENSEMBLES ALL PROJECT NORMAL TO BELOW-NORMAL RAINFALL (ON AVERAGE) NEXT 2-3 WEEKS: