Tuesday, July 25, 2017

Downturn Continues

Models were very good yesterday in forecasting the downturn to continue. Much different picture yesterday for detected CGs above (from Atmo and Vaisala) for 24-hours ending at 6:00 am MST this morning, as thunderstorm activity was much reduced. Precipitation for same period (below from ALERT) across metro area was focused around the airport - TUS reported 0.49" while we had just 0.01 here from light afternoon sprinkles.

The morning TWC sounding (above) remains very moist and continues with some CAPE as the BL mixes more deeply this afternoon. However, nearly unidirectional wind profile means anvils heading out ahead of any mountain storms that would develop, hindering their advance toward lower elevations. Warm temperatures continue in middle levels.

The WRF-GFS from midnight run last night (below - valid through 6:00 am tomorrow morning)) forecasts little rainfall over southern Arizona, as the downturn continues.

The trough off California does not shift further south, and PW remains high, which is good for a return to better conditions as the 500 high builds again and shifts back to Four Corners/Great Basin region. The GEFS 500 mb spaghetti plot at bottom shows the longer term adjustments to large-scale pattern (valid at 216 hours - 00 UTC on August 3rd).

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