Rain Train coming to LA; Pair of stunners on tap for Chicago
Seasonably warm and sunny weather will abruptly come to an end on Wednesday afternoon as another series of powerful Pacific storms pushes onshore. If you thought the flooding was over - think again! The very active eastern Pacific continues to pound California. The culprit for this upcoming week will be an extremely powerful Pacific jet that slams head-first into the California coast. The jet is positioned just far enough south to tap into that all-important subtropical moisture. The result will be a series of - possibly - 4(!) storms continuing through the weekend. The GFS model is forecasting 3-4" of rain for the Los Angeles coastal plain during this period!!
Unlike the storms in late December and early January, with this set of storms, Los Angeles looks set to reap more of the spoils. Just to jog your memory - Los Angeles has received 8.8" of rain since October 1, about 150% of year-to-date average.
A powerful jet stream pounding the west coast will translate to a weak, flat ridge in the central US. While the models are forecasting a flatter ridge than they were a few days ago, the Midwest and central US still looks to benefit from strong southerly flow and rising heights. The result will be a pair of clear days on Wednesday and Thursday with temperatures in the Chicago area pushing into the upper 40s and maybe low 50s.
A weak warm frontal band will ride along the top of the ridge on Friday but will aggressively fill in as the ridge builds from the west. Saturday and Sunday could be the warmest days of the winter so far for Chicago with temperatures topping out around 50 as a pulse of southerly flow invades the area. Of course, things could (and probably will) change by then, but the models have been consistent in bringing this warm-up for several days now. The result will be a pair of mid-week sunny stunners.
Here's a look at the GFS modeled surface temperatures for Thursday afternoon (we usually consider other factors when forecasting surface temps, but this gives an idea):
And, while it's a long way off, for Sunday afternoon:
One thing that remains consistent is that Chicago is right on the boundary between very warm air and colder air to the north. We'll wait and see how the ridge materializes.