942 FXUS63 KMPX 121155 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 555 AM CST Sat Jan 12 2019 .UPDATE... Issued at 542 AM CST Sat Jan 12 2019 Updated to include 12z aviation discussion below. && .SHORT TERM...(Today through Sunday) Issued at 230 AM CST Sat Jan 12 2019 Surface analysis early this morning depicts a weak north-south oriented surface trough over central MN, associated with a dissipating northern-stream low pressure center over western IA. The larger more potent southern stream low pressure center continues to slowly shift east over southern OK. High pressure over south-central Canada spreads southeast across the Great Lakes into the Mid-Atlantic and New England regions. Aloft, a potent cutoff low over southern KS continues to drive the motion of the southern-stream low while a sharp ridge stays stoic just of the west of the Rockies. Over the next 12-24 hours, the ridge will expand eastward over the northern Rockies through to the Great Lakes while a weak trough in advance of the ridge slides south over southern MN/WI. Sufficient mid level moisture with the trough will maintain cloud cover over the area for much of the day. However, lesser low level moisture plus weak forcing will mitigate precipitation production (zero QPF) so have opted to run with a dry forecast. The ridge filling in to the north along with approaching high pressure will help suppress the southern-stream low pressure system to the south, far enough such that no precipitation from that system will reach into MN/WI. That system will then shift east into the Tennessee River Valley while high pressure expands over the Upper Mississippi River Valley tonight through Sunday. More breaks in the clouds are expected for Sunday, mainly for far southern MN and southwestern WI. Temperatures both today and Sunday will run rather similar, due to the lack of airmass change even with the passage of the weak trough and incoming high pressure. Highs both today and tomorrow will run in the mid 20s to lower 30s. Lows early this morning and early Sunday morning will range from the mid teens to lower 20s. .LONG TERM...(Sunday night through Friday) Issued at 230 AM CST Sat Jan 12 2019 Overall pattern shift looms in the longer term resulting is a shift from mild/dry conditions to much colder regime by late in the week. We see a relatively calm period early with the main jet energy riding well north of the CWA. This does gradually shifts south with time as the significant southern stream storm exits off the east coast. This allows a couple of cold fronts to drop south into the area. The first arrives Tuesday afternoon. We should see mild temepratures, possible warming through the upper 30s the first part of the week. The front appears to move through the area dry Tuesday evening with the better forcing/deeper moisture shunted to the northeast. The deterministic models diverge greatly by the end of the week, by how deeply the area will remain in the cold air with the passage of the secondary cold front on Thursday. This front will bring at least a chance of snow to the region Thursday perhaps into the day Friday. The ECMWF has trended much colder with the area becoming entrenched in the colder air by Friday and lingering through next weekend. The GFS brings the cold front through Thursday but holds out for one last system to move through next Monday before the arctic surge takes place. Still, the trend toward much colder looks good through the end of next week, with perhaps some light snow with cold frontal passage. && .AVIATION...(For the 12Z TAFS through 12Z Sunday morning) Issued at 502 AM CST Sat Jan 12 2019 Ceilings will prevail throughout this TAF set, it's a matter of whether they're VFR or MVFR. MVFR ceilings occupy much of north- central thru western MN and it's expected that's where they'll stay (thus impacting KAXN-KRWF primarily). Remaining TAF sites are expected to have ceilings settle in the 040-050 height later this morning through tonight. No precipitation expected at any of the TAF sites. Winds will run generally NE in the 5-10 kt range. KMSP...Not expecting ceilings to drop to MVFR range but it cannot be completely ruled out. Will look for ceilings around 050 to develop later this morning and remain there tonight through Sunday morning. /OUTLOOK FOR KMSP/ Sun...Mainly VFR. Chc MVFR ceilings. Wind SE 5 kts becoming SW. Mon...Mainly VFR. Chc MVFR ceilings. Wind SW 5 kts. Tue...VFR. Wind SW 5-10 kts becoming NW. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ UPDATE...JPC SHORT TERM...JPC LONG TERM...DWE AVIATION...JPC