163 FXUS63 KMPX 191945 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 245 PM CDT Thu Sep 19 2019 .SHORT TERM...(This evening through Friday night) Issued at 245 PM CDT Thu Sep 19 2019 Temperatures and humidity levels continue to be abnormally warm for this time of year across the Upper Midwest. These readings are more typical for August vs. mid September. Latest satellite imagery this afternoon depicted the remnants of the decaying thunderstorm complex across eastern Wisconsin. In the wake of this complex, very little change in the atmosphere was noted along the Iowa border. There is even a gradient line noted in the local radar across far southern Minnesota where low clouds lingered through the afternoon. The main forecast concern is how widespread or isolated will the convection become later tonight, and on Friday. There is a subtle wave noted across central Nebraska this afternoon. Models have this feature moving northeast across eastern Nebraska, and into northwest Iowa/southwest Minnesota late tonight. Moisture advection associated with this feature is weak, but I wouldn't be surprised to see a few showers or storms develop along it late tonight. This feature will likely continue to enhance a few showers or storms across southwest/south central Minnesota after sunrise Friday. It may even continue to spread northward Friday afternoon, but typically an increasing inversion should keep most of the activity isolated at best. The latest CAMs suggest that most of the activity will be isolated with the main concentration of storms across the Dakotas. Late Friday night should see an increase in showers and thunderstorms activity, especially in western Minnesota as the frontal boundary nears, and the upper level energy moves closer to the region. Still, the bulk of the precipitation should hold off until after 12z Saturday. .LONG TERM...(Saturday through Thursday) Issued at 245 PM CDT Thu Sep 19 2019 The longer term concerns remain convective potential Saturday along with cooling temperatures. Saturday continues to indicate severe potential, especially if morning convection/cloud cover remains sparse and we get heating/destabilization ahead of the surface cold front. Timing would bring the front into central MN Saturday afternoon and will be the focus for any real convection. Models indicate around 2500 J/kg MLCAPE and around 35kts shear associated with boundary as it moves through. Better lift will move across central/northern MN and there are some indications of a secondary wave traveling farther south over IA/MO region. This may split forcing, but still looks like there will be a severe threat for much of the central and eastern CWA Saturday afternoon/night. This system exits the region Sunday morning leaving clouds and cooler air moving into the area on breezy west/northwest winds. There may be some showers over the northeast CWA into Sunday afternoon in the CAA/cyclonic flow remaining behind exiting cold front. Timing of the next frontal boundary remains in question with the deterministic models bring it through in the Tue/Wed time frame. We will retain the smaller end PoPs for this at the moment and see if models come into better agreement on timing. Also, the ECMWF shows indicating of split flow developing with cutoff circulation travels south of MN ate next week. The GFS continues to develop the trough to west but builds the southeast CONUS ridge well into the central Mississippi River valley. This would leave MN/IA region close to the surface boundary and susceptible to more prolonged heavy rain threat. Will need to monitor model trends through next week. High temperatures will cool through the 70s early next week, with highs possible struggling to reach 70 by the end of next week. No significant signal for frost seen through at least the next seven days. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 1220 PM CDT Thu Sep 19 2019 No aviation concerns this afternoon or evening as low cigs/vsbys and chc of TSRA will be south of MPX Taf area. After 6z, cigs/vsbys will likely deteriorate across eastern Minnesota, and into west central Wisconsin. LIFR cigs/vsbys will be possible near KEAU. Otherwise, a small chc of TSRA late tonight as a frontal boundary moves northward across southern Minnesota. The best chance of TSRA will occur after 18z/20. KMSP... No additional concerns through 6z. After 6z, there is an increasing chc of MVFR/IFR conditions. Chc of TSRA are low at this time before 18z/20, but increase during the afternoon. /OUTLOOK FOR KMSP/ Fri evening...VFR. MVFR/IFR in TSRA. Wind SE 10G20 kts. Sat...AM MVFR/TSRA likely. Wind SW 15G25 kts. Mon...VFR. Wind W 10G20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...JLT LONG TERM...DWE AVIATION...JLT