781 FXUS63 KMKX 101840 AFDMKX Area Forecast Discussion National Weather Service Milwaukee/Sullivan WI 140 PM CDT Wed Oct 10 2018 .UPDATE...Light to moderate rain will continue over the ern half of WI through 21Z. A broken line of showers and possibly isold tstorms along the cold front over sw WI will move ewd through the remainder of the afternoon. No longer anticipating any short term flooding problems other than the rivers that are already in flood or are forecasted to rise to flood stage. The 999 mb Low over west central WI will deepen and occlude to the ern portion of Upper MI and Lake Superior tnt and reach near James Bay, Canada around 00Z Fri. Strong cold advection and gusty winds to 30 to 35 mph tnt-Thu. Temps will fall into the upper 30s to middle 40s by sunrise Thu and remain in the 40s through the day. && .AVIATION(18Z TAFS)...Cigs of 1-3 kft this afternoon through Thu AM with Cigs locally below 1 kft within and near areas of rain. Cigs then rising to 3.5-4.0 kft Thu afternoon and possibly becoming scattered. Winds becoming wly late this afternoon and evening and gusting to 30-35 kts through Thu. && .PREV DISCUSSION... (Issued 1113 AM CDT Wed Oct 10 2018) UPDATE...Warm conveyor belt rain will gradually shift ewd across srn WI through the middle of the afternoon. Heavy rainfall rates have been periodic and brief and this will continue into the afternoon. Cannot rule out at least minor street flooding in the metro areas of se WI. Will cancel Flood Watch over wrn WI where widespread rain has ended. A broken line of showers and possibly tstorms will occur with the frontal passage this afternoon. Very minimal CAPE less than 300 J/KG will be available. Showers and storms will be fast moving and add only minor additional rainfall. The cold frontal passage will occur late afternoon and early evening with wind gusts around 30 kts tnt-Thu AM. MARINE...A Small Craft Advisory remains in effect until 02z Thu from Port Washington to Sheboygan and points north due to high waves from a persistent sly flow. Afterward, a Gale Warning is in effect from 02z Thu until 17Z Thu for the entire open lakes of Lake MI and the nearshore area from Sheboygan south to Winthrop Harbor, IL. A strong cold front will sweep across the lake this evening with west-southwest gale force wind gusts. The winds will gradually weaken Thu afternoon into the evening. PREV DISCUSSION... (Issued 616 AM CDT Wed Oct 10 2018) UPDATE... Rain is spreading into south central WI early this morning. This is out ahead of a warm front. Look for this band of showers and thunderstorms to gradually shift east through the day. AVIATION(12Z TAFS)... MVFR ceilings are spreading into south central WI early this morning. We will see a mix of MVFR and IFR ceilings today. The band of showers and scattered thunderstorms will gradually shift east through the day. These lower conditions will persist until the cold front pushes through, with improving CIGS by evening. Expect gusty westerly winds overnight in the wake of the front. We could see a period of VFR behind the front and then MVFR ceilings should develop late tonight or Thursday morning. PREV DISCUSSION... (Issued 342 AM CDT Wed Oct 10 2018) SHORT TERM... Today and Tonight...Forecast Confidence is Medium to High. Low pressure will slide from northeast Iowa to northeast Wisconsin today. Within the "warm conveyor belt" and strong moisture transport, there is a line of showers and isolated thunderstorms that extends from southern Missouri through western Wisconsin and up through Eau Claire this morning. Heavy rain is possible as precipitable water values are up to 1.8 inches, well above normal for this time of year. The flood watch still looks valid, so no change to the headline. The line of showers and thunderstorms will gradually slide east through the afternoon as the cold front gives it a nudge. Given the strong shear along the front, there is a marginal risk for severe storms. Instability will be weak, but the shear could make up for it and give us the risk for damaging winds or a brief tornado this afternoon. Winds will increase out of the west-southwest late this evening in the wake of the cold front and persist through the night. Temperatures will go from the lower 70s late this afternoon to around 40 degrees by late tonight with this strong front. LONG TERM... Thursday and Friday...Forecast Confidence High... By Thursday morning the surface front will be well east of the area, with temperatures starting the day in the upper 30s to around 40. Highs will only warm a few degrees into the mid 40s, given continued cold air advection from the northwest and a widespread stratocu deck. Those gusty northwest winds will keep wind chills in the mid 30s for much of the day. Temperatures Thursday night/early Friday morning are expected to fall to right around freezing. Winds may stay up just enough to limit frost formation in some areas, though any place that is sheltered from the wind will have good frost potential. On Friday, surface high pressure will be moving through the lower Missouri Valley, but aloft, another shortwave will be passing through the area. This will result in continued cloud cover, and a chance for a few sprinkles across far southeastern Wisconsin. Highs Friday will again be in the mid 40s. Saturday through Next Wednesday...Forecast Confidence Moderate... Forecast confidence has improved a bit going into the weekend, as it now looks fairly likely that we will see a parade of clipper systems move through the region on active northwest flow. Even then, exact timing, strength, and especially moisture availability/precip potential are still subject to change. For now, it looks like Saturday will be mostly dry, with temperatures recovering a bit into the low 50s as surface flow becomes southwesterly. Another front is then expected to move through late Saturday or early Sunday, and this will have at least some light rain with it. High temperatures will likely be knocked back into the 40s for Sunday and Monday, with lows in the low 30s. Frost will be a good bet both Sunday and Monday nights. Another clipper is progged to then move through in the Tuesday or Wednesday timeframe. This would bring yet another shot of light precip to the region. AVIATION(09Z TAFS)... A strong low level jet will bring low level wind shear to southern WI early this morning. Look for VFR conditions through about 12z. The steadier rain should remain just to the west of Madison through 09z. Then MVFR CIGS will begin to spread quickly west to east across the area through the mid to late morning as a strong trough of low pressure/cold front push in. We should see a mix of MVFR and IFR CIGS. These lower conditions will persist until the cold front pushes through, with improving CIGS by evening. The front will push through KMSN around 20z Wed and KMKE/KENW/KUES around 21-22z Wed. MARINE... A Small Craft Advisory remains in effect from 12z this morning to 02z Thu from Port Washington to Sheboygan and points north due to high waves from a persistent sly flow. Afterward, a Gale Warning is in effect from 02z Thu until 17Z Thu for the entire open lakes of Lake MI and the nearshore area from Sheboygan south to Winthrop Harbor, IL. A strong cold front will sweep across the lake this evening with west-southwest gale force wind gusts. The winds will gradually weaken Thu afternoon into the evening. && .MKX WATCHES/WARNINGS/ADVISORIES... WI...None. LM...Gale Warning from 9 PM this evening to noon CDT Thursday for LMZ643>646-669-671-673-675. Small Craft Advisory until 9 PM CDT this evening for LMZ643. && $$ Update...Gehring Today/Tonight and Aviation/Marine...Cronce Thursday THROUGH Tuesday...Boxell