New weather trend coming 

Posted: 6:59 am Thursday, June 14th, 2018

By Kirk Mellish

We’ve returned to a tropical air mass with more than usual cloud cover and more than usual coverage of showers and storms, something we’ve done three times already here in the spring and early summer.

While I can’t issue the all clear on rain or storm odds or give a completely sunny forecast, it does look like the trend is our friend the next 5-7 days, and MAYBE beyond.

Higher than normal moisture in the air and upper level low pressure, surface fronts or troughs, and bits of energy aloft have all conspired to give us our latest bout of unsettled weather.

prog00hr

Notice at 10-20,000 feet over the Southeast there is low pressure and vorticity with a weakness in the upper level heights:

ruc00hr_700_tmpeta12hr_500_vrt

However, moving forward the height levels increase as upper level high pressure builds and strengthens as we finish the rest of the week and head through the weekend, vorticity lessens and total atmospheric moisture content lowers at least a little as seen in the forecast progs:

eta48hr_500_vrteta84hr_500_vrt

gfs066hr_700_tmpgfs090hr_700_tmpgfs114hr_700_tmp(NCAR graphics)

So while there is no day without some cloud cover and no day without at least some chance of rain or a storm, the trend is for less of both allowing the heat to build and increasing the number of dry areas and dry hours through next Thursday.

The weekend heat index (combo of temp and humidity on how it feels) will reach as high as 96, and that’s in the shade. Add 15 for direct sunlight.

Remember, even with little sun the temperature in a closed car can soar rapidly to dangerous levels for pets and children. Beat the heat, check the back seat. Even when its not too hot or if it’s cloudy, the invisible infrared rays penetrate the car windows! And with any sun:

Screen Shot 2018-05-25 at 7.21.02 AM

The ensemble temperature guidance from the GFS and European model (split the difference):

KATL_2018061500_min_max_16KATL_2018061500_eps_min_max_15

Nonetheless, it still looks like heat will not get out of hand in terms of degrees or number of hot days in a row as odds of pop up storms will return to at least normal or above normal again longer-term, but the latest GFS and ECMWF Ensembles show drier to finish out June with more heat:

gfs_precip_anom_conus2_65(38)eps_tprecip_a_conus_61(10)

IF El Nino continues to come on as expected, it also suggests a lack of extremes for the end of summer and start of Fall.

El Nino Temp and Rainfall anomalies:

Screen Shot 2018-06-14 at 8.30.39 AMScreen Shot 2018-06-14 at 8.30.12 AM

Follow me on Twitter @MellishMeterWSB.

 

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