502 FXUS63 KMKX 091923 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 223 PM CDT Tue Oct 9 2018 .UPDATE...Sct showers and tstorms will occur this afternoon with SBCAPE's of 1500-2000 J/kg and no capping. Isold to sct showers and storms will probably continue through the evening and overnight via moisture transport, but the more widespread showers and storms will occur on Wed. 1002 mb low pressure area over ern KS will track to north central WI and gradually deepen to 997 mb by 00Z Thu. The strong upper wave lifting nwd from the srn Rockies to MN will continue the deepening Wed nt across Ontario, Canada. A strong cold front will sweep ewd across srn WI late Wed aft- early eve. PWs will increase to 1.8 inches tnt and remain high on Wed until fropa. South to north bands of showers and embedded tstorms will train some, but ewd movement will increase through the day. Thus will not make any changes to the Flood Watch which is in effect for Sauk, Iowa, and Lafayette Counties. && .AVIATION(00Z TAFS)...Cigs of 3.5 kft this afternoon into the evening along with sct showers and storms. Cigs will then fall to 600-1900 feet from west to east across srn WI from early Wed through late morning. The Cigs may improve to 1-3 kft during the afternoon. Vsbys will be reduced at times tnt-Wed with the rain and possibly light fog. && .PREV DISCUSSION... (Issued 546 AM CDT Tue Oct 9 2018) UPDATE... The forecast looks on track early this morning. A few showers will move northeast through parts of south central Wisconsin into early this morning. Most of the showers and any storms should remain just to the west of the area this morning. May see widely scattered showers and storms later this afternoon into the evening, mainly in south central Wisconsin. Gusty winds may accompany any storms. More widespread showers and storms should slowly push east into the area mainly tonight. Flood Watch in effect for the far western counties tonight into Thursday morning, for possible heavy rainfall over already very moist ground conditions. AVIATION(12Z TAFS)... Low level wind shear is expected until around 13Z this morning, with southwest winds at 2000 feet around 35 knots. A few showers may affect Madison, though most of that activity should remain west of the area into the morning hours. May see more widely scattered showers and storms from the middle of this afternoon into early this evening, especially west of Madison. Some gusty winds may occur with the storms, with brief MVFR category conditions. Lake breeze with southeast winds are expected in the afternoon near Lake Michigan, which may impact Milwaukee and Kenosha. More widespread showers and storms moves slowly east into western portions of the area later this afternoon and tonight. May see locally heavy rainfall with this activity. VFR conditions are expected into this evening across the area. Western portions of the area may see MVFR category ceilings and visibility values later tonight. PREV DISCUSSION... (Issued 349 AM CDT Tue Oct 9 2018) SHORT TERM... Today And Tonight...Forecast Confidence Is Medium. Most of the showers and thunderstorms should remain just to the west of the area into this morning, closest to the 925 mb frontogenesis response and focused warm air advection/low level jet nose. Mesoscale models were showing the potential for a few showers and storms to clip the far west, which is plausible given how close the showers and storms are. Will keep some PoPs going in the western parts of the area into this morning to account for this. Another warm and humid day is expected today across the area, on south winds. Highs should be similar to yesterday, despite some middle to high clouds lingering. Record highs are 82 at Milwaukee and 85 at Madison for today, with Milwaukee having the best shot at breaking its record high. There should be a lake breeze developing in the afternoon, which would cool things down in those areas. Airmass will be unstable and uncapped, with tall skinny mean layer CAPE and fairly robust deep layer shear. Mesoscale models were showing widely scattered showers and storms developing in the middle to late afternoon hours, best chances in the western parts of the area. These storms could produce gusty winds. Will keep some PoPs going for the afternoon to account for this. Low level frontogenesis response and focused warm air advection/low level jet nose then slide slowly eastward later this afternoon into tonight, bringing more widespread showers and storms into western portions of the area. The far eastern parts may remain fairly dry. Continued higher end PoPs west to east into tonight. Enough concern for moderate to heavy rainfall in the far western counties tonight into Wednesday morning to issue a Flood Watch. Mesoscale models are showing some potential for a line of showers and storms to move over those areas later tonight. May get another 1 inch of rainfall, possibly more in localized areas. In addition, the Flood Watch area would be more sensitive to any additional moderate to heavy rain, given recent rainfall and subsequent flooding. LONG TERM... Wednesday and Thursday...Forecast Confidence High... By Wednesday morning the frontal boundary will begin to make eastward progress as the surface low lifts from Iowa into Central Wisconsin, and eventually lower Michigan by evening. An area of rain and a few thunderstorms will likely be ongoing ahead of the front, with a secondary line of showers/thunderstorms along the actual boundary. Exact timing will likely vary a bit over the next 24 hours, but current indications are for the front to arrive across the west during the mid afternoon, reaching Lake Michigan by early evening. Temperatures will drop very quickly behind the front, as 20-30 MPH west winds usher in a much colder airmass. Look for temperatures by Thursday morning to fall into the upper 30s to around 40. Thursday will be a dry but chilly day, with temperatures only reaching the mid 40s. We'll likely have a fairly widespread stratocu deck across the area, and with west to northwest winds between 15 and 20 MPH, with gusts to 30-35 MPH, wind chills will be in the low to mid 30s for much of the day. Thursday Night and Friday...Forecast Confidence High... High pressure will settle in across the Central Plains Thursday night into Friday, with surface winds becoming more northerly and decreasing in intensity. Lows Thursday and Friday night will fall to around freezing, with frost likely, especially in sheltered areas way from the wind. Highs on Friday will only be in the low to mid 40s. Saturday to Next Tuesday...Forecast Confidence Low... Forecast confidence really tanks heading into the weekend, as precipitation chances will largely hinge on the evolution of two systems. The first will be a strong shortwave diving south from the Canadian Rockies, which will carve out a large trough across the central and northern Plains over the weekend into next week. The second system will be the remains of Hurricane Sergio, which is currently expected to make landfall in the Baja Peninsula late Thursday, and move into Oklahoma by Saturday. This system could potentially remain well to our south, or phase with the northern stream system to bring a solid shot of precipitation to the area over the weekend into early next week. If precipitation does affect the region, it seems most likely to occur Sunday and Monday. As far as temperatures, for now have highs in the upper 40s and low 50s, with lows in the 30s, but that will also depend on how these two systems evolve. Needless to say, please check back often over the coming days as changes to the forecast are likely. AVIATION(09Z TAF Update)... Low level wind shear is expected until around 14Z this morning, with southwest winds at 2000 feet around 35 knots. Most of the showers and storms should remain west of the area into this morning. May see more widely scattered showers and storms from the middle of this afternoon into early this evening, especially west of Madison. Some gusty winds may occur with the storms, with brief MVFR category conditions. Lake breeze with southeast winds are expected in the afternoon near Lake Michigan, which may impact Milwaukee and Kenosha. More widespread showers and storms moves slowly east into western portions of the area later this afternoon and tonight. May see locally heavy rainfall with this activity. VFR conditions are expected into this evening across the area. Western portions of the area may see MVFR category ceilings and visibility values later tonight. MARINE... Nearshore Waters...South winds will increase on Wednesday, ahead of a strong cold front. May see gusts to 25 knots occur on Wednesday. Waves may build to 3 to 5 feet, especially north of North Point Lighthouse. A Small Craft Advisory may be needed. Gusty west to northwest winds are expected behind the strong cold front for later Wednesday night into Thursday night. Gusts to 30 knots are likely, with some gale force gusts not out of the question. A Small Craft Advisory will be needed for this period. Open Waters...Gusty west to northwest winds are expected behind the strong cold front for later Wednesday night into Thursday night. Gusts to 35 knot gales are possible, with building waves on the east side of Lake Michigan. A Gale Watch may be needed for this period later today. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...Flood Watch from 7 PM CDT this evening through Wednesday afternoon for WIZ056-062-067. LM...None. && $$ Update...Gehring Tonight/Wednesday and Aviation/Marine...Wood Wednesday Night through Tuesday...Boxell