397 FXUS63 KMPX 081819 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 119 PM CDT Sun Sep 8 2019 .UPDATE... Issued at 100 PM CDT Sun Sep 8 2019 Updated for the 18Z aviation discussion below. && .SHORT TERM...(Today through Monday) Issued at 336 AM CDT Sun Sep 8 2019 Satellite imagery early this morning had a mid-level circulation over northeast South Dakota. Ahead of this circulation, stronger ascent and deep moisture will continue to produce scattered showers through noon. This circulation is forecast to weakened/dissipate by the afternoon with a general trend of decreasing areal coverage and intensity of the showers. The heaviest, and most concentrated area of showers will occur in southwest Minnesota where better isentropic lift will be present early. Elsewhere, occasional light showers will slowly end with cloudy skies continuing. Temperatures will reflect the denser cloud cover and occasional showers with highs only reaching the mid to upper 50s, to around 60 degrees. This is 15 to 20 degrees below the normal high of early September. As this system weakens this afternoon, the focus for more showers will develop ahead of a stronger system moving out of the Rockies late tonight. Monday will start out cloudy with showers developing in the southwest, and rapidly spreading northeast during the day. Chances of thunderstorms also increase Monday as a warm front lifts northward. Severe weather will be concentrated south and west of Minnesota until late in the day as steepening mid-level lapse rates and wind shear increases. Lows tonight may actually start to rise in southwest/west central Minnesota as winds shift to the south/southeast and slowly increase. Highs on Monday will likely occur late in the day, and possible into the evening as moisture steadily increase along and ahead of the warm front. .LONG TERM...(Monday night through Saturday) Issued at 336 AM CDT Sun Sep 8 2019 Main story for the extended has not changed one bit, the upcoming week looks very active, with 2 to 5 inches of rain pretty much area wide, much of that coming in systems impacting the area Monday/Monday night and Wednesday into Thursday night. We'll also be in west to southwest flow, so it will be warmer and more humid than what we've been experiencing lately as well. Both systems this week will come from the h5 low just off the BC coast. Lead shortwave energy associated with the negatively tilted trough generating thunderstorms from Nevada to BC this morning will lift across the northern Plains Monday, with WAA associated with it sending showers and thunderstorms through the area Monday afternoon and evening. The heaviest precip this system looks to come Monday evening, when the LLJ increases to over 50 kts from southeast MN into western WI. The main upper wave will then go from the Dakotas Thursday to northwest Ontario on Friday, bringing a second round of showers and thunderstorms Wednesday into Thursday night. In both cases, some severe weather will be possible, but we look to have extensive cloud cover and rain, so the degree of instability is in question, though the system for Wednesday/Thursday looks to bring the greatest potential for seeing more significant instability and threat for severe weather. Heavy rain looks like a certainty at this point given Pwats in excess of 1.5" for both systems. For temperatures, 80 still looks to be an elusive number for the Twin Cities. Tuesday still looks like our best shot in the Twin Cities of hitting 80 with mainly sunny skies expected, but we've seen the NBM drop highs into the 70s for most areas with slightly cooler air progged to drop in behind the low that moves across northwest MN Monday night. 925mb temps going into Wednesday and Thursday will be more than warm enough to support some 80s, but extensive cloud cover and rain look to hold temperatures back both days (but not dewpoints, which will climb back into the mid/upper 60s). However, looking at the GEFs, we aren't done with chances to hit the 80s as mean h5 forecast shows we more or less hold this trough west/ridge east pattern through basically the rest of the month, which means continued warmer and more active weather will hold for much of September (as noted by CPC with their 8-14 day and weeks 3-4 outlooks). As for the active pattern note, both the GFS and ECMWF show the next system due in already next weekend. && .AVIATION...(For the 18Z TAFS through 18Z Monday afternoon) Issued at 100 PM CDT Sun Sep 8 2019 For the remainder of the day, MVFR/IFR cigs across southern and especially southwestern MN will expand slowly northward, especially after 00Z. Ceilings will lower tonight and fairly widespread IFR is expected. For Monday, another strong system across Montana will lift a warm front into southern MN with shortwave energy extending from Montana across the Dakotas into Minnesota. This will produce widespread showers and thunderstorms across the area, with MVFR and IFR conditions possible. KMSP...Can foresee two rounds of thunder tomorrow, a late morning round and late afternoon. Confidence on exact timing is low, so in the TAF, kept VCTS through the day. /OUTLOOK FOR KMSP/ Tue...VFR. Chc -TSRA/MVFR overnight. Wind SW bcmg W at 10 kts. Wed...VFR. Chc -TSRA/MVFR. Wind E at 5 kts. Thu...VFR. Chc MVFR. Wind turning NW 10-20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ UPDATE...SPD SHORT TERM...JLT LONG TERM...MPG AVIATION...SPD