Slight Uptick Tomorrow?

Not much changing. Last three days Tucson has had a high temperature of 100F. Low level moisture has increased very slightly and lows have stayed up in 60s here at house. This morning's (Thursday September 16) Tucson sounding has come in with data that are too moist by 4 to 5 mm when compared to the GPS PW. The data plot seems to indicate that the humidity sensor was responding slowly to changing RH and damping down the actual trends.

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This morning's 0600 UTC run of the Atmo WRF-GFS model indicates a slight uptick in thunderstorm activity to the east of Tucson tomorrow. The model forecasts a brief increase of low-level moisture coming in from the east (top image is 850 mb Td at noon tomorrow). This leads to some increase in storm activity off to the east (middle image is model-simulated composite radar reflectivity at 2 pm tomorrow).

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Bottom image shows that TS Karl is now over the Bay of Campeche. Karl is forecast to become a hurricane before making landfall on the Mexican coast. The ECMWF continues to forecast the remnants of Karl to move westward over the mouth of the GoC early next week.