Heat and Humidity Return

Jonathan Carr
By August 6, 2021 10:07

Heat and Humidity Return

Discussion: The key upper-level change for this weekend is the dissolution of the upper-level low/trough in the E US and the establishment of a weak ridge. This will allow the troposphere to expand (positive geopotential heights) and bring back the more traditional mid-summer feel rather than the late-summer/early fall taste we’ve recently experienced. Ultimately surface flow will change back to the SW or S and which will build our heat and humidity. I expect this to last all weekend and well into the near future before we see another cold front relieve us. I am watching a weak coastal disturbance that could enhance rain and storms Saturday PM into Sunday AM but how much impact is still yet TBD. I’ll likely provide a quick update tomorrow (Saturday morning) to summarize the latest data and thoughts. I would like to point out that this summer and last summer seems to lack the 100+ actual temperature heat waves. However, we’ve seen relentless humidity (dew points of 76+ for days at a time). There’s a direct relationship between humidity and heat surrounding wet bulb dynamics. A drier atmosphere is allowed to to reach higher temperatures (think desert). An extremely humid atmosphere however actually keeps temps from climbing outrageously above 100 (think tropical). This is why our excessively hot feeling days have only been in the 90s not 100s. We’ve seen higher temps before many times. But my goodness the humidity this year! Just my .02

We’re well into our descent towards fall. You should already notice the slightly earlier sunsets. The sea surface temperatures are nearing their annual peak and the tropics are likely going to “enter the chat room” soon, at least in the lower latitudes of the Atlantic Ocean. There’s not much going on right now but when it does (likely soon), I will make sure to stay focused on anything that could impact NJ either directly (landfall potential) or indirectly (remnants slide up the east coast).

Friday (Aug 6) high temperatures should reach near-90 for most areas, maybe slightly hotter for interior CNJ/SNJ. Coastal areas closer to 80. Skies should be mostly sunny with increasing humidity. Winds should be light out of the SW. Overnight lows should range from mid-60s to near-70 from elevations to coasts.

Saturday (Aug 7) high temperatures should reach the mid-to-upper 80s for most areas. Again, coastal areas closer to 80. Skies should be mixed with sun and clouds with a humid feel. Showers and thunderstorms are likely during PM hours. They could start as early as afternoon and last overnight. Winds should be light out of the S (while not under a t-storm). Overnight lows should range from near-60 to near-70 from elevations to coasts.

Sunday (Aug 8) high temperatures should reach the mid-to-upper 80s for most areas. Coastal areas could hang in the upper-70s especially after the sea breeze front advances inland. Skies should be mixed with sun and clouds with a humid feel. Can’t rule out a rogue thunderstorm or two in this setup for all of NJ. Wildcard: SENJ has a chance to start wet with a nearby weak coastal disturbance but that should clear by late-morning if around. Winds should be light out of the S/SE. Overnight lows should range from near-60 to near-70 from elevations to coasts.

An early look at next week indicates more of the same. Temps near or just above 90 for most (near-80 for coastal areas). Humid. A mixed bag of sun, clouds, and isolated-to-scattered PM thunderstorms. Let’s take another look on Sunday. For now, everyone please have an amazing weekend and be safe! JC

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Jonathan Carr
By August 6, 2021 10:07