Discussion...interesting developments within the past few hours. It still looks nothing like it should for middle July...but we have a more definitive moisture push underway from the Gulf of California this morning. Kyum has had a 2mb pressure rise in 6hrs with south-southeast 15-20kt flow up to 3kft and a dewpoint in the lower 70s. Dewpoints have also risen into the upper 50s-lower 60s along the Colorado River and at several alert gages west and SW of kphx. Ktus sounding precipitable water is up to 1.18". Mixing things out, assuming zero moisture advection, still keeps the precipitable water near 1" and gives US about 500 j/kg cape. 30kt 3-6km shear from the NE is favorable for some organization despite the weak cape...and the local is just above the freezing level which is favorable for microbursts. Southeast Arizona remains caught in an upper level shear axis which may serve as a Focal Point for development today...but upper level static stability within the shear zone is still high since the upper high is almost vertically stacked. Recent GOES precipitable water loops also show a little drying underway over Cochise County and SW nm -- perhaps because of some weak subsidence. Ktus dewpoint...after briefly hitting 59f this morning...has begun to fall again and was at 56f at 9am. In summary...we have conflicting information in terms of thunderstorm coverage and intensity today. We'll stand pattern with current forecast since the general idea of isolated valley/scattered mountain thunderstorms looks good. But if this moisture push can continue a few more hours...we could be looking at a slight upswing late this afternoon and evening.And let's make a plea to Hurricane Emily too: spare the islands and bring us your wetness.
All of the models are now saying ktus's first monsoon day could be tomorrow. NGM...ETA model and GFS-based MOS all jump the ktus dewpoint into the upper 50s-lower 60s tonight and keep it there into the weekend. Although we're not 100 percent convinced...a continued moisture seepage today...an even stronger surge tonight...or somewhat better thunderstorm coverage this evening would do the trick. In addition...both ETA model and GFS indicate a change in upper high geometry by Friday such that it will not be vertically stacked like it is now. If that happens...the other negative factor we've had in addition to the lack of moisture will be removed. Again...this is hardly where we should be in middle July...but it's a start. We'll take a close look at trends from both the models and observational data today...but initial thought for the afternoon package will be to bump probability of precipitation up slightly Fri/Sat...retain the downward trend Monday/Tuesday as the high is pushed back overhead...and then start shading in upswing day 6/7 as the high shifts back north and the remains of Hurricane Emily moisten up central Mexico after landfall early next week .