UA WRF Forecast Discussions

Overview: As Hurricane Beryl is poised to potentially become the earliest Atlantic Basin category 4 storm in the satellite era as it bears down on the Windward Islands of the Carribean, southeastern Arizona is facing its own set of weather challenges. Relatively saturated soil from activity over the past 48 h combined with the potential for significant rainfall today has led the Weather Prediction Center (WPC) to place southeastern Arizona in a slight risk area for excessive rainfall. This indicates at least a 15% chance of rainfall exceeding flash flood guidance in a 25 mile radius around any point in the slight risk area. This also corresponds to a National Weather Service (NWS) Issued flood watch. Additionally, the Storms Prediction Center (SPC) has indicated a marginal risk (5% chance) of severe winds in our region and corresponds with a blowing dust advisory issued by the NWS. The threat of severe convection is being supported by a combination of deep moisture being advected into

  Synopsis Mid level clouds associated with an MCV from overnight convection in Sonora will likely suppress storm development through this afternoon. Isolated storms will be possible in any areas that can receive enough clearing. CAMs are hinting at the possibility of organized storms in Sonora moving northwestward into SE AZ later this evening into the overnight hours. This activity looks to slowly weaken as it moves into Arizona. Tomorrow looks to be a very active day across SE AZ with more widespread storm coverage and possible significant impacts. Yesterday/Monsoon 2024 Climo An active day across SE AZ yesterday with quite a few strong cells in the Tucson vicinity. Tucson International Airport received 0.70 inches and other gauges across the area receiving widely variable amounts from a trace to close to one inch. A couple storms had wind gusts reach severe criteria with reports of a 58 mph gust and a few trees uprooted via SPC storm reports. SPC Storm Reports yesterday for Pima Co

  Synopsis The mid level subtropical high will remain centered near the AZ/MX border today with weak westerly flow over AZ. Still plenty of moisture and instability in place to produce scattered showers and thunderstorms mainly in SE AZ this afternoon and evening. A slightly better chance for a few cells in Tucson this afternoon due to a combination of high DCAPE (better outflow boundary potential) and weak upper level divergence. Main impacts from storms will be lightning, gusty winds, blowing dust, and brief heavy rainfall. Current Conditions The mid level anticyclone remains anchored near the AZ/MX border this morning with weak westerly winds aloft over AZ. SPC 500mb analysis as of 16z this morning. The only change to the synoptics today is a weak, subtle region of upper level divergence indicated by SPC 300mb analysis this morning. SPC 300mb analysis as of 16z this morning. This region of divergence is associated with the right entrance region of a 300mb speed max over the Four Cor

  Synopsis The mid level anticyclone will remain centered near the AZ/MX border today and tomorrow with westerly flow aloft over AZ. Even with an unfavorable upper air pattern, sufficient moisture and instability remains in place for a chance of afternoon and early evening showers and thunderstorms over the higher terrain today and tomorrow. Even though convection should remain outside the major population centers, there remains a slight chance for an isolated cell or two to reach the Tucson vicinity today and tomorrow. Marginal drying and a closer ridge center will raise high temps a few degrees but should remain just below excessive heat criteria.  Current Conditions At 9:00AM MST, visible satellite imagery and lightning detection displayed a localized area of strong thunderstorms along I40 east of Flagstaff and scattered high clouds across SE AZ. Visible satellite imagery overlaid with GLM flashes at 9:00AM MST courtesy of College of Dupage. The synoptic pattern has changed consider