The height pattern moving forward in essence will be pretty stagnant; meaning, the same synoptic features that have been more-or-less in the same regional locations show really no sign of letting up. The EPS for instance, along with the GEFS and GEPS, are in remarkable agreement regarding the persistence of the heat ridge across the lower southern states of the U.S. From a climatological standpoint, verbatim the EPS we’re dealing with a ridge that’ll be over 1.5 standard deviations, so we’ll be dealing with quite the persistence in days of heat from NM to LA.

If we simply look at the next 1-2 weeks, the core of the warmest temperatures remains tenaciously over the deep South and into the Southwestern states where temperature anomalies exceed anywhere from 5 to 10 degrees above normal. This animation below runs out to the start of July!

Lets compare the probabilities of surface temperatures reaching a minimum of 90*F and 100*F. A wide swath of high to very high confidence regarding 90*F from AZ to LA basically today through the last week of June. Contrasted to the 100*F probabilities, we see that it’s confined mainly toward southern AZ, NM, and TX as these areas will receive the “brunt” of the “dry” heat.

The issue is that because of the placement of the surface high pressure, and shortwave troughs that shift from the West into the Plains, then cross the U.S. allows for persistent advection of moisture from the Gulf as denoted below. It’s the latent heat via moisture from the Gulf that’ll send heat indices into the triple digits, and for quite a bit making this a dangerous scenario for heat-related illnesses and concerns. Running the GFS for example up to near July 4th shows unrelenting heat indices surpassing 100*F.

There are some signs that once we get into the week of July 4th, that the pattern will begin to break down and reshuffle, causing the heat ridge to retrograde and weaken to an extent. However, that is quite a bit out and what’s most important is that those living in these states in the southern Plains and deep South will have to maintain awareness regarding heat-sensitive health concerns. Stay hydrated and cool! You really don’t know how quickly dehydration can set in! Please check in on the elderly especially!