The break in the extreme heat is coming just as forecast, you can see the first weak cold front approaching on the Friday morning surface weather map above. We had 9 consecutive days of 90 or above. This has been the warmest May on record in Atlanta where records go back to 1878!
The streak with no rain stands at 18 days in a row.
If you are very lucky the front will produce a shower or thundershower for you later today, but the odds are too low for me to put in the formal forecast. The front will help drop temperatures and humidity the next few days so no worse than 90 the next 5-10 days and many of us will stay in the upper 80s (normal this time of year is 83) with more comfortable temperatures overnight with morning lows 59-67.
Another weak cold front moves through late Sunday-early Monday but again the slight chance of a shower with it is not worth getting excited about.
It looks like a more typical summertime chance of pop-up thundershowers by late next week with better odds next weekend and the week beyond. MOST of us will not see an afternoon high above 90 for the next 7-15 days.
After all that coolish weather and the wet period of March/April and the first half of May the reversal now has our rainfall surplus for the year down to just over half an inch.
I talked about the summer outlook in several previous blogs and tweets.
Short-term drought is spreading across the Southeastern U.S. worse in SE Georgia:
Meanwhile the center of the country gets hammered by flooding rain and tornadoes with late season snow in the Rockies and Desert Southwest. But as the amplified jet stream pattern breaks down and reconfigures itself less extreme weather is expected for at least a few days to a week.
Some 8 locations set new record high river levels already and several more may set record high flood levels in the days to come, at least 5 cities set new monthly rain records for wettest May in history including Chicago.
Notice the rainfall and temperature contrasts and extremes across the country one extreme or the other:
Jet stream “blocking” pattern with blocking high pressure aloft over Greenland and Alaska with amplified pattern “goosed” by MJO energy/lift from the South Pacific. Baroclinic zone in temperature contrast is the storm track where flooding and tornadoes occur thanks to stuck pattern as disturbances repeatedly ride along within the jet stream flow:
(CBS News graphics)
This active tornado season follows a 7 year period of low tornado numbers and a record low in the most violent EF 3-5 twisters. 2018 had a record low number of twisters.
YTD only 2008 and 2011 had more tornadoes than this year to date since 1950 with 1006 tornado reports so far this year.
As the pattern breaks down the high pressure ridge over our region heads back to a more normal location for summer out West/Southwest:
This allows temperatures to back down a little and scattered showers to increase a little as we move further into June:
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