Aikyam-Lab/Synoptic-Bench huggingface dataset:
The GFS is the outlier in advecting much cooler 850mb temps than the other models, and given its poor track record lately have largely ignored its guidance. Days 2-7 are closer to the ECMWF which is 3-5 degrees warmer than the GFS MEX. The reason for the cooling trend this week will be high pressure to the west flattening, and spreading east causing flow to become more easterly.
230 AM CDT Sat Aug 31 2019 Rather tranquil northwest flow resides with mean upper ridge across Pacific northwest and mean trough over northeastern states.
305 AM CDT Sat Aug 31 2019 06Z surface data has high pressure over the Great Lakes and upper Midwest with a cold front in the Ohio Valley.
Light winds may help keep temps up for the next few hours, but still looking for values to fall into the lower to mid 60s for most places tonight.
A drier airmass will be filtering in from the east this weekend, so look for reduced rain chances, more sun, and warmer daytime temps.
Lower PWATs and lack of any forcing will mean little to no shower activity on Saturday, even in the highest terrain of the San Juans.
This afternoon, a stationary front was over far southern Indiana as high pressure was building across the Upper Midwest. Winds will become northeast tonight as the center of the ridge moves toward Lower Michigan.
1145 PM EDT Fri Aug 30 2019 Large area of strong high pressure remains centered over the Upper Midwest and the Great Lakes region late this evening. with overnight lows ranging from the low to mid 40s along the shoreline areas to the upper 30s across the higher elevations of Northern Lower Michigan. Pattern synopsis/forecast: Large area of Canadian originated high pressure steadily building into the area this afternoon as northwest flow aloft continues. Given fast flow aloft, large scale features expected to remain progressive, allowing center of high pressure to settle directly overhead tonight. Expect widespread readings in the lower and middle 40s by sunrise Saturday, with our typical colder locations in the Au Sable River Valley up into interior northeast lower likely dropping into the upper 30s (perhaps even a few degrees colder).
High pressure over southern NV will gradually shift east to center over the Four Corners by Saturday evening. After this evening, high pressure will shift further east and a more northerly flow will be over the Panhandles.
Sunday night upper high pressure will start to build back in over the area and bring dry conditions.
1223 AM CDT Sat Aug 31 2019 A cold front across southeast Illinois, south of I-70, will be the focus for scattered showers and isolated storms through tonight. Additional chances for showers and isolated storms will come Saturday and Saturday night, with the overnight period having the higher chances of rain. A swirl of energy moving across southern Illinois along the cold front will be the focus for periodic showers across areas south of I-72 tonight. If that occurs, lows near Galesburg could dip into the mid 50s, while areas south of I-70 see low temps in the low to mid 60s. Labor Day is still looking dry and mostly sunny, with highs near to above normal in the low to mid 80s.
In between the two ridges is a surface boundary that moved through the area very early today, in conjunction with heavy rain and strong thunderstorms. Light rain and cloud cover could linger most of the day before drier and warmer weather returns for the last half of the holiday weekend. Mid-level height rises will occur on Sunday as a mid-level ridge over the Four Corners region expands northeastward.