625 FXUS63 KMPX 100020 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 620 PM CST Tue Mar 9 2021 .SHORT TERM...(This evening through Wednesday night) Issued at 226 PM CST Tue Mar 9 2021 As often happens with record breaking temperatures, we'll see big changes in the weather in the upcoming 24 to 36 hours as much colder air (and snow) work into the area. The main forecast concerns are the potential for accumulating snow late Wednesday and Wednesday night, and the small chance for thunderstorms and severe weather over the southeast portion of the area Wednesday afternoon/early evening. Temperatures have warmed nicely today, although the warming has been delayed along the I-35 corridor where a thick patch of clouds was present through around noon. Warmer temperatures are apparent west and east of that corridor at the current time, with mostly sunny skies under a canopy of cirrus. Temperatures should manage to inch up a bit more through around 4 PM before cooling off, then the upstream cold front will move through most of the area tonight. The front will stall late tonight from around Albert Lea through Eau Claire, and a developing surface low will move northeast along that baroclinic zone on Wednesday. There remains some disagreement with where exactly the low will track, which hinges on how far the front makes it tonight and how much the surface low intensifies Wednesday (with the stronger solutions being farther north/west). Its position will help determine where the axis of heaviest snow will be in the west/north portion of the area late Wednesday afternoon into Wednesday night. Didn't change the going forecast too much in that regard, with plowable snow still in the forecast from west central into central Minnesota. Subsequent forecasts should be able to better pin down location and amounts, with a winter weather advisory likely forthcoming later tonight for a portion of the area. Across the southeast part of the forecast area, thunderstorms will be a concern Wednesday into early Wednesday evening, and the surface low track will play a role in their location as well as whether or not any severe weather occurs. There is some possibility that we'll see a pocket of instability (with MLCAPE AOA 500 J/kg) work into the southeast portion of the area Wednesday afternoon into early evening. Forecast hodographs are impressive, with low-level (0-1 km) SRH in excess of 300 m^2/s^2. However, there is significant uncertainty with this forecast, so it will simply need to be watched tonight into Wednesday. The southeast portion of the area would be favored from a synoptic perspective given the forecast track of the surface low from the RAP and NAM, but boundary layer temperatures will dictate whether or not convection will be rooted there and able to take advantage of the strong shear which is forecast. If it's able to do so, then some isolated severe weather would be possible (damaging wind gusts and an isolated tornado from any low topped supercell that's able to form in such an environment). At this point it appears to be a low probability potential, but will bear watching. The system will move northeast Wednesday night, taking precipitation with it, and most of the area should be precipitation-free by Thursday morning. .LONG TERM...(Thursday through Tuesday) Issued at 226 PM CST Tue Mar 9 2021 As we pick up the extended portion of the forecast, the Low Pressure system is on the way out of the area over the northern Great Lakes, and as it continues to move eastwards we will see broad high pressure begin to move in behind it. This broad area of high pressure will ride the northern edge of an upper level jet, pushing towards the Great Lakes and out of the area by the middle of Sunday, as a broad trough swings northeastwards from the central Rockies. As this trough continues to move and strengthen, a broad surface low will develop and affect the central and northern plains beginning late Sunday and continuing into Monday before diminishing. Right now the trajectory of the trough would keep the center of the low fairly far to the south in southern Iowa to northern Missouri, which would keep most of the sensible weather down that direction as well. GEFS ensemble members have a QPF range of anywhere from about an inch to nothing at all, with an average of around 3 or 4 tenths of an inch. This will of course change going forward as we clue in on the track of the system and the overall amount of moisture available. There is also the question of precipitation type, and for now that remains just as much an uncertainty given the unknown track. Temperature wise it looks like we remain above freezing, but only just on Monday morning, so overall scenario right now would be rain for most, with a chance for a zone of mixed precipitation trending towards snow on the northernmost portions of the area. More details should become available as we get a bit closer, especially once we resolve the system moving through the short term period. Otherwise, with a couple slow meandering systems, we shouldn't expect any major shakeups over the rest of the period in terms of sensible weather. Most days will see a mix of clouds and sun with temperatures in the low to mid 40s for highs and low to mid 30s for lows which climate wise would be just a bit below normal, as highlighted in the 6-10 and 8-14 day Climate Prediction Center outlooks. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 619 PM CST Tue Mar 9 2021 VFR conditions will persists into the overnight hours, but ceilings drop to MVFR tomorrow morning and eventually to IFR as widespread rain spreads north across the region. Some breaks in the rain are possible during the afternoon, but generally expect an extended period of IFR ceilings and visibility from the late morning into the late afternoon. Isolated thunder is possible across eastern Minnesota and western Wisconsin so have included a prob30 mention for now, but confidence is low overall for the thunder risk at any particular site. The rain is expected to changeover to snow at AXN by late afternoon tomorrow, but will hold off until the end of the period at other central MN sites. KMSP...Fairly high confidence on the arrival time of precipitation tomorrow morning, but still unwritten on how long rain will fall during the morning and afternoon. Expect IFR visibility during the rainfall with ceilings also dropping to IFR during the late morning. A few breaks are expected at times, but should fill back in fairly quickly. An isolated rumble or two of thunder can not be ruled out as well, but overall chances look low. Rain could change over to light snow late Wednesday night as the precipitation diminishes, but little or no accumulation is expected. /OUTLOOK FOR KMSP/ Thursday...MVFR early, becoming VFR. NW wind 5-15 kts becoming W. Friday...VFR. NW wind around 5 kts. Saturday...VFR. W wind 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ SHORT TERM... LONG TERM...TDH AVIATION...ETA