Tucson (TWC) — the National Weather Service forecast in plain English · Plaincast

Synopsis

Temperatures will be near normal today as the first in a series of Pacific Storm Systems move through the region. Expect late morning into early evening showers and thunderstorms. Some of the storms could contain brief heavy rain, small hail, and gusty winds. Addiotinal rain chances return next week as the pattern remain unsettled.

Discussion

Current regional analysis shows an upper level low moving onshore over northern Baja and SoCal. A few lightning strikes are evident with some of the stronger convection moving onshore. This will traverse our area later today, brining scattered to numerous showers (30-80%) and isolated thunderstorms (10-30%). While overall areal averages of rainfall will be anywhere from a 0.1" to 0.35", localized amounts under heavier showers or storms could see upwards of 0.6"-0.9". RRFS/REFS and the high-res rapid-refresh model show an organized line of showers with embedded storms to the east and northeast of the upper level low center. With 25-40 knots of 0-6km shear and 200-700 j/kg of SBCAPE, we cannot rule out a strong storm or two with small hail, heavy rain, and gusty winds to 45 mph. The probs of gust in excess of 45 mph are 10-20% with pockets of 40%. REFS also show some isolated and low probs of a gust or two to 58mph. RRFS also shows this potential as the line of storms become more organized as it pushes across the Tucson Metro. The best chance for any isolated severe gusts would be NE of Tucson where the greatest probs exist. While we are mentioning this, the overall probable of happening are quite low.

If some of the CAM solutions are correct, there could be some minor/nuisance flooding across the metro depending on rainfall rates. Not expecting any flash flooding or anything signfciant.

The system departs fairly quickly by this evening with lingering showers into the late evening. Enough moisture and instability will be around for Game Day Festivities on Saturday, but should only amount to sprinkles or a very brief light shower. temperatures look pretty great with highs around 70 degrees across the Metro. Bear Down.

Once this system passes, there will be shortwave high pressure allowing for a dry period Sunday and Monday. Daytime highs will be in the 70s lower deserts and 60s higher desert valleys.

The second system begins to dig down the West Coast and brings the next round of precipitation late overnight Monday into late overnight Tuesday, with some lingering showers into Wednesday morning. The models continue to have different timing as to when this system weakens as a third system digs down behind it late next week. Regardless, rainfall totals of 0.01"-0.60" is possible with the highest amounts in the mountains, and in Pinal County and along the International Border. Snow levels may come down low enough for some flurries at the top of Mt Graham and White Mountains, but no accumulation is expected. Temperatures begin to decrease to below normal, with the coolest day on Wednesday.

This active pattern looks to continue into next weekend with a third system, with more details being ironed out as we get closer and models come into more agreement.