MAJOR Pattern Change for the Southwest CONUS

[wxmann_91]

Many of the AFD's (too tired to post them) point out a major pattern change for us, more rain, possibly even for Arizona. Two storms, one of which may tap into some subtropical moisture. Models have been fairly consistent though the lastest run of the GFS significantly backs off the second system.

Thoughts anybody? Or is this thread going to die an early death like so many of my other threads did?

[Aslkahuna]

Based upon what the models are showing at this time, I would say that the only area where rainfall of 0.25in or more would fall would be north of a Parker to Winslow line with nothing over 0.10in below that line and probably less. It would not help the Drought situation at all for two reasons-first the area having the strongest drought conditions (the White Mountains down into Cochise/Santa Cruz/eastern Pima Counties) are not expected to get much of anything. Secondly, it's too little too late. The snowfall deficit depending upon elevation in the mountains of northern AZ is running about 100-200 inches and I seriously doubt that this pattern could deliver that kind of snowfall. Heights down here are not expected to fall below 570 dam which is not a very good value for rain down here-we usually need 564 or lower.

Steve

[wxmann_91]

Unfortunately that is true, and the WFO Flagstaff and Pheonix aren't too enthusiastic. OTOH WFO Oxnard mentions 2-4" of rain possible along the coast and valleys, and WFO San Diego mentioned 1-2" possible, with the possibility of rain lasting all week if the ECMWF verifies.

[Aslkahuna]

Trajectory is everything-our best moisture trajectory is from the SW during the Winter and the moisture has to be deepened enough by dynamics to clear those 10k peaks in Baja. SW from PHX means that the air has to originate about 30N or around Ensenada-for us it has to originate from around Punta Eugenia (the Spur of Baja). Low level from the Sea of Cortez is useful if the storm has the proper (negative) tilt but this one is positive tilt. Hopefully when the front punches through it might generate a line of showers when it hits the terrain to our west but those lines are good for only about a tenth or so. Since December 1st, we have had 0.37in of rain which is about 15% of normal. March is the last month
of the winter rainy season here and we would need 3 inches of rain just to break even and that hasn't happened very often in March (only once in the past 100 years, I believe and that was in a Niño year).

Steve

[aveosmth]

This is going to be a HUGE storm on Monday night!!!! Can't wait!!