####018004344#### FXUS63 KFSD 122345 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 645 PM CDT Wed Aug 12 2026 .KEY MESSAGES... - Showers and thunderstorms are likely again tonight into Thursday morning. The main threats will be locally heavy rain (better chances south of I-90) and strong winds up to 70 mph (better chances near the Missouri River into parts of northwest IA). - Areas of dense fog and low stratus may form again late tonight into Wednesday morning, though confidence in coverage is low. - Cloud cover and cooler temperatures move in for Thursday into the weekend. Periodic showers and storms expected. Humidity lingers. && .DISCUSSION... Issued at 121 PM CDT Wed Aug 12 2026 A pair of waves move onto the Plains tonight. The first will be associated with the right entrance region of the upper jet to the northwest. This may bring some some stronger storms to central SD later this evening. An isolated severe storm will be possible. Later tonight a more subtropical wave moves from CO into northern NE and may interact with a much more unstable environment. If this develops it will likely become linear with heavy rain and wind gusts to around 70 mph likely. The better chances for this coming together will be near the Missouri River into northwest IA, likely from about 2 am to 7 am. CAPE values likely running about 20000-4000 J/kg with moderate deep layer shear. Once this activity exits the area, fairly stable air settles in for much of Thursday into Thursday evening. Thursday morning may see some low stratus and patchy fog, with these clouds lifting a bit but likely lingering through the day. This should limit warming a bit with highs likely remaining in the 70s. However with these cooler temperatures will not come a drop in humidity with dew points still likely in the mid 60s to lower 70s. Later Thursday night into Friday morning a weak wave will lift north into the area and should bring weak to moderate warm air advection in the low to mid levels. With the potential for maybe 1000 J/kg CAPE a few thunderstorms will be possible, with the better chances in northeast NE and northwest IA. Severe weather is unlikely but local heavy downpours are possible. Friday afternoon and Friday night weak upper level ridging will build and likely suppress any convective activity. However Saturday into Saturday evening showers and thunderstorms will likely redevelop with very isolated severe storms and locally heavy rain possible. Faster northwest flow aloft will be north of the area Monday through Wednesday next week. This will keep a slightly cool air mass in place during this time with highs generally from 75 to 85 each day. Periodic weak waves will move through and bring chances for showers and thunderstorms with low confidence on strength and timing right now. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 644 PM CDT Wed Aug 12 2026 Latest satellite shows mid and high level clouds overspreading the area to begin the TAF period. Currently, any showers and storms remain mainly west river. These showers and storms will push eastwards through the evening hours and reach the forecast area during the late evening to early overnight time period. Some uncertainty remains regarding how expansive the showers and storms will be so have included PROB30 groups in all TAFs. The bulk of the rain looks to fall south of I-90 at this time. Ceilings look to also lower to MVFR/IFR levels both while rain is falling and after the rain moves east. Visibilities look to fall to MVFR levels while it is raining but could be lower in localized areas. Chances for rain will be coming to an end through the morning hours. However, low level stratus may linger around for longer than currently anticipated. Will see how tonight's activity plays out before potentially extending the timeframe of the low level stratus. Otherwise easterly winds will finish out the TAF period. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...08 AVIATION...Meyers ####018006029#### FXUS61 KRLX 122345 AFDRLX Area Forecast Discussion National Weather Service Charleston WV 745 PM EDT Wed Aug 12 2026 .WHAT HAS CHANGED... Updated PoPs to better represent observations and trends. Also, took out mention of thunderstorm chances until the late morning and early afternoon as the threat for thunderstorms remains low for the overnight. 00Z Aviation Forecast Discussion update. Little to no changes made from previous forecast cycle. Blanketed overcast skies and anvil blow off have promoted a stable atmosphere over the area today, with severe weather potential staying west in Indiana. Model trends suggest a window of storm development around midnight tonight, but could be dependent upon antecedent convection. Will continue to closely monitor satellite and radar this afternoon to determine propagation and probability of storms later on today. && .KEY MESSAGES... 1.) Prolonged risk for flash flooding stems into the second half of the work week amid daily chances of showers and storms across the Ohio Valley. Torrential rainfall tied to these storms will exacerbate already saturated soils. 2.) Additional showers and storms are possible into early next week, but a brief interlude from active weather takes shape for the start of the weekend. && .DISCUSSION... KEY MESSAGE 1... The weather in our forecast area looks vastly different than it did this time yesterday. Convective debris spilling in from storms firing up in the Ohio Valley this afternoon has kept us in a more stable state, with temperatures hovering in the mid 70s. Satellite views upstream sheds light on the path of least resistance of today's storms, currently taking a southeast dive from Indiana into Kentucky. The eastern flank of this line, encompassing much of Ohio, has retained mostly stratiform rain with some embedded thunder, and hasn't made much forward progress into the Ohio River Valley throughout the course of the day. Hi-res model guidance tends to struggle with a weather pattern such as this, so closely monitoring satellite and radar trends will be apparent for situational awareness and forecast updates heading into this evening and overnight. Any showers or storms that reach the Central Appalachians through the near term are not expected to reach severity levels such as what we faced yesterday, but could impose strong wind gusts and torrential rainfall. Given very saturated soils from previous rainfall this week, any heavy downpour that reaches the forecast area could yield localized high water issues. No changes were made to the ongoing Flood Watch, which remains intact through Friday morning amid this active weather pattern. Convective trends for the area will remain indicative of upstream evolution of storms each day through the end of this week. KEY MESSAGE 2... The upper level weather pattern shows no signs of varying through this week, maintaining the Central Appalachians in an area prone to daily showers and thunderstorms. The start of the weekend trends slightly drier with the mass exodus of the stalled front, but may quickly fill back in with additional convection aiming for the Central Appalachians for Sunday and onward. Limited severe and hydro concerns are expected in the long term outlook as it currently stands. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... Slight chances for an isolated light shower early tonight with cloudy stratocu dominating the sky. The area should then dry out. With the potential for some breaks in cloud coverage as well as antecedent soil conditions patchy fog is likely in the valleys and some surrounding areas. Some fog may spill into sites such as PKB/EKN and affect restrictions down to IFR but not expecting much else other than some MVFR in fog at the other sites excluding BKW who will have enough surface flow to deter fog, although will likely have low stratus for the mid morning. After 13/14Z any fog should dissipate, however low MVFR CIGs will hover around until the early afternoon at which point will lift to VFR. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Overnight restrictions caused by low ceilings and/or fog may vary from the forecast. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE THU 08/13/26 UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11 EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07 CRW CONSISTENCY H H H H H H M M L L L L HTS CONSISTENCY H H H H H H H H H L L L BKW CONSISTENCY H H H H H H L H M L H M EKN CONSISTENCY H H H H M M H M L L L L PKB CONSISTENCY H H H H H M L H L L L L CKB CONSISTENCY H H H H H H H H M M M H AFTER 00Z FRIDAY... Any clearing of skies will likely result in patchy stratus or fog during the overnights given very wet ground conditions. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Flood Watch through Friday morning for WVZ005>011-013>020- 024>034-039-040-515>526. OH...Flood Watch through Friday morning for OHZ066-067-075-076- 083>087. KY...Flood Watch through Friday morning for KYZ101>103-105. VA...Flood Watch through Friday morning for VAZ003-004. && $$ DISCUSSION...05/JZ AVIATION...JZ ####018005118#### FXUS63 KGRR 122347 AFDGRR Area Forecast Discussion National Weather Service Grand Rapids MI 747 PM EDT Wed Aug 12 2026 .KEY MESSAGES... - Chance for Isolated Thunderstorms This afternoon and evening - Foggy and chances for light rainfall through the south to end the work week - Precipitation Chances This Weekend && .DISCUSSION... Issued at 234 PM EDT Wed Aug 12 2026 - Chance for Isolated Thunderstorms This afternoon and evening Low stratocu continues to remain through the southern tier of Michigan with light southerly winds. Severe weather through Indiana continues to track to the south east with any outflow moving northward running into a wall of stability. That stability will stifle any convection this afternoon and evening through southern Michigan. The sole caveat will be convection from boundary interactions. Currently there is three different outflow boundaries moving in different directions that are set to intersect through southwest MI. There are some CAMS that suggest that some convection could form. SFC based CAPE is around 1000 J/KG along the I 94 corridor. However, there is upwards of 200 J/KG of CIN. So while it is possible that convection could form through the south and will need to be watched, the stable air could preclude storm development. The better chance will be as a speed max moves from the east to southeast across central lower MI. Lapse rates in the tri city area are 6 to 7 C/km through the mid levels. Couple that with MU CAPE around 1400 J/KG and PWATS of 1.43 inches and you have a decent environment for storm development. There is some cu development through central and norther lower. However, a large cirrus shield should limit daytime heating, though Max temps along the US 10 corridor could get into the mid 80s. Latest CAMS continue to suggest the potential for isolated storms to be possible after 20Z. DCAPES are in the 800 to 900 J/KG range so Damaging winds are the main concern. Any shower and storm chances will dwindle through the evening hours, - Foggy and chances for light rainfall through the south to end the work week Any rainfall and convection will add to the moisture throughout the lower levels through southern Michigan. Calm winds, a stable air mass and moist lower levels is a great recipe for another round of fog through Thursday morning. Expect areas of fog to develop overnight. Fog could be denser than this morning's but will hold off on any advisories for now. Another upper level trough will drop down from the west tomorrow. The track of that trough is trending towards this week's previous systems. They are trending towards IN south into Ohio. The only precipitation could be on the fringes along the I 94 corridor. Only light rain is expected with a low chance for any thunder. - Precipitation Chances This Weekend The next chance for widespread precipitation will be Saturday night and Sunday as the pattern shifts and the zonal flow shifts northward bringing a mid level shortwave propagates over high pressure building into the Great Plains. That short wave will bring decent surge of moisture Sunday. There is some question on timing an position of the mid level trough. However there should be good thickness advection with MUCAPE values in excess of 2000 J/KG. So there is the persistent trend for the potential for stronger storms. Mid to long range models also continue to show a 35 to 40 kt 850mb jet through Lower Michigan Sunday morning. This will aid storm development Sunday. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 745 PM EDT Wed Aug 12 2026 MVFR ceilings persist early this evening along the I-94 corridor, including AZO/BTL/JXN. As discussed previously, these clouds have indeed been slower to erode during the day. Even though these clouds may ultimately break up for a brief period this evening, this set up will likely exacerbate the development of IFR fog and vsbys again tonight in all areas, given elevated dew points, recent rainfall, and light winds. The low clouds and fog area-wide /IFR conditions/ will dissipate roughly 12-13Z, with a few CU/SC and thickening mid/upper clouds thereafter /VFR/. Winds will remain light and variable throughout the TAF period, with the exception of an onshore lake breeze at MKG after 18Z. && .MARINE... Issued at 247 PM EDT Wed Aug 12 2026 Not expecting much winds and waves over the next few days. The main concerns will be the potential for marine fog and any thunderstorms moving from the west in the afternoons. Fog will remain a threat over the water until drier dew points move into the region. That does not really happen this week so the threat of fog will continue through the rest of the week. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. MARINE...None. && $$ DISCUSSION...Ceru AVIATION...Smith MARINE...Ceru ####018004718#### FXUS63 KARX 122349 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 649 PM CDT Wed Aug 12 2026 .KEY MESSAGES... - A linear mesoscale convective complex capable of producing damaging winds will likely move southwest and south of the forecast area late tonight and Thursday morning. - Heavy rain will be possible along and south of Interstate 90 from Thursday into Saturday. && .DISCUSSION... Issued at 154 PM CDT Wed Aug 12 2026 Tonight and Thursday The 12.12z models are in general agreement that a shortwave trough, currently located over eastern Idaho and central Montana, will move east across South Dakota and Nebraska this afternoon and evening. As this occurs, scattered showers and storms will develop. With 0-6 km shear over 40 knots, some of these storms will become supercellular. As the evening progresses, the cold pools will coalesce and a linear mesoscale convective complex will develop on the nose of a 30-40 knot low-level jet. Wind gusts could be in the 60 to 80 mph. At this time, it looks like these winds would be southwest and south of the area overnight and southeast of the area on Thursday morning. Low temperatures will be in the lower and mid-60s tonight. High temperatures will range from the mid-70s to mid-80s. The cooler temperatures will be along and south of Interstate 90 where there will be a better chance of showers and storms from late tonight into Thursday. Thursday night into Saturday 2 to 3 shortwave troughs will move along the northern periphery of a 500 mb ridge centered over the western Gulf. In addition, a stationary front will linger across northern Iowa, southern Wisconsin, and northern Illinois. Surface-based CAPES will range from 2000 to 3500 J/kg south of this front. With precipitable water values will range from 1.5 to 2.25 inches along and south of Interstate 90 and warm-cloud layer depths around 4 km, heavy rain will be possible. From Thursday night into Friday south of Interstate 90, there is up to a 30 percent chance for 1 inch or greater and up to a 15 percent chance for 2 inches or greater. With weak 0-3 km and 0-6 km shear, not anticipating any organized severe weather. High temperatures on Friday and Saturday will range from the mid-70s to lower 80s. Low temperatures on Thursday night and Friday night will range from the mid-50s to mid-60s. Saturday night into Sunday night The models are continuing to trend more and more south with the frontal boundary. As a result, the rain chances were reduced some. If this trend continues, we may have to eventually remove the rain chances. High temperatures on Sunday will range from the mid-70s to lower 80s. Low temperatures will be in the lower and mid-60s on Saturday night and range from the lower 50s to lower 60s on Sunday night. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 649 PM CDT Wed Aug 12 2026 While a few areas of diurnal cumulus remain across the region, benign conditions are expected through the rest of the evening with light and variable winds. Overnight, mist/fog looks to be on the table again with the highest confidence in fog development across northeast Iowa and southwest Wisconsin. The 12.21z NBH MOS guidance suggests 20-40% probabilities for less than 3SM visibilities across these areas, though the 12.18z REFS has nearly nonexistent probabilities for the same conditions which leads to some uncertainty in how widespread mist/fog would become especially considering increasing mid-cloud cover is expected from the west overnight. Because of this uncertainty, confidence in visibility impacts at the TAF sites remains fairly low, so have opted to not include in the TAFs. Along with the fog potential, showers and storms move eastward out of the Great Plains overnight. Similar to the last few nights, expectations are for the strongest showers/storms to remain south of the area, although areas along and south of I-90 do have a 60-80% chance for rainfall through the morning hours and have included PROB30 groups to the TAFs to account for this potential. Additional showers and storms may develop in the afternoon on remnant boundaries from the morning round, but confidence in where these would develop is low. Primarily VFR conditions are expected outside of any shower/storm activity Thursday afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Boyne AVIATION...Falkinham ####018007868#### FXUS63 KJKL 122349 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 749 PM EDT Wed Aug 12 2026 .KEY MESSAGES... - The potential for showers and thunderstorms will persist through the end of the week. The greatest coverage is expected from today through Thursday night. Some of the storms could arrive as organized clusters with a possibility for strong to damaging wind gusts, mainly this evening. - Excessive rainfall may occur where storms are most persistent, leading to flash flooding - particularly tonight. - A Flood Watch is now in effect for the entire forecast area through 8 am Thursday morning. && .SHORT TERM...(This evening through Thursday night) Issued at 613 PM EDT WED AUG 12 2026 Our area is still beneath west northwest flow in the mid-upper levels, on the edge of faster flow to our north northeast, and will continue to be in this general scenario. A broad frontal boundary is laid out NW- SE through KY, with very warm and humid air impinging on the boundary from the southwest. This scenario continues to favor periodic thunderstorm complexes propagating southeast over our area, initiated by rather weak features and remnant features from prior convection. As in recent days, these features are very difficult for models to handle, especially very far in advance. That being the case, aside from the very near term, the precip forecast continues to be broadbrushed and based on model blends. The first convective system is currently entering the area from the northwest. Instability varies across the thermal gradient in our area, with northeast locations having only weak instability, while the southwest portion of the area looks to have 100mb mixed layer CAPE near 3K J/KG. Hence, the greatest risk for strong storms with wind should be in our southwest counties as storms roll through this evening. There is also still a deep moisture gradient present, with PWs near 2" over the western portion of the area, but around 1.5" in the east this evening. This also puts the western part of the area at greater risk initially for excessive rainfall. However, higher PWs should progress eastward. The Flood Watch was extended through 12Z Thu with collaboration with neighboring offices. This could be further extended, but will leave that decision to the overnight shift. As already mentioned, forecast confidence is lacking after tonight. A model blend would suggest that the next heightened POP will be Thursday night, especially in our northeast counties. However, precip at other times is certainly a possibility. .LONG TERM...(Friday through Wednesday) Issued at 357 PM EDT WED AUG 12 2026 At the onset of the long term period, eastern Kentucky will find itself in continued northwest flow aloft, sandwiched between ridging over the southeastern CONUS and troughing over the Northeast. At the surface, an area of low pressure will sit over Atlantic Canada, with a long and poorly defined cold front extending back through the Mid Atlantic, just north of the forecast area. This front will sag south through the area on Friday, bringing a chance for additional convection. As in previous days, the environment will support intense rainfall rates with any convection that does pass through; LREF mean PW values range from 1.8-2 inches on Friday afternoon, well within the 90th percentile or higher when compared to climatology, and given already moist soils, flash flood risk could be higher than in typical summer thunderstorms. WPC has maintained a Day 3 Marginal (1/4) flash flood risk for our area to account for this. Additionally, at least moderate instability is likely to build ahead of the front, which could potentially support strong convection. Given some model guidance suggests the potential for additional shortwave impulses within broader northwest flow aloft, additional MCS type activity cannot be ruled out on Friday (although uncertainty remains high). That being said, upper level flow will be weak, with deep layer shear generally favored to remain under 30 kts across the forecast area, which would not conventionally support widespread severe weather. Even so, some machine learning guidance has been comparatively more aggressive in highlighting eastern Kentucky as a potential location for additional damaging winds. Given some of the signals in global models, it is still plausible that MCS activity could increase the potential for severe wind gusts Friday afternoon/evening, although confidence in this scenario remains very low. For now, NBM PoPs were maintained given a lack of baseline model agreement, but with the caveat that rain chances/timing will require some refining as uncertainty decreases. By the weekend, the front will have passed through the forecast area. Meanwhile, the upper level ridge will continue to build into our area. This will usher in a period of hotter and drier weather, with high pressure working to suppress most convection through the weekend. Unfortunately, the aforementioned cold front will do little to bring down heat or humidity. Behind the front, temperatures will actually trend warmer in accordance with increased upper level ridging (highs likely in the 90s), and dewpoints will remain in the 70s. Accordingly, apparent temperatures will be warm, likely in the upper 90s or perhaps even the low triple digits on Saturday and Sunday afternoons. Overnight temperatures will only provide limited relief given a continued moist environment; although radiative conditions will be ideal, valleys may only end up being a few degrees cooler than ridges at most, with typical valley fog formation possible overnight. Early next week will mark a return to more quasi zonal flow aloft as an upper level trough begins to dig toward Kentucky and ridging retreats to the southwest, initiating a return to a somewhat more active period. Notably, an approaching cold front on Monday will bring renewed shower and storm chances. In comparison to the previous cold front, the air mass behind this front will be marginally drier, with dewpoints expected to fall into the mid to upper 60s in most locations. High temperatures will also be around 5 degrees cooler for most locations, marking a return to a more typical August weather regime. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) ISSUED AT 749 PM EDT WED AUG 12 2026 Showers and thunderstorms were ongoing over portions of the area at TAF issuance. The most intense storms, with a potential for strong winds, were over the southwest part of the forecast area. Activity further northeast was weaker. The thunderstorms could bring IFR or worse conditions this evening to all but our northern TAF sites. Locations near/north of I-64 have already had this batch of thunderstorms move through and should be VFR into the night for at least a while. There is another possibility of thunderstorms overnight and at times on Thursday. However, there is lower confidence in the forecast at those times, and only PROB30 groups were used in TAFs. Aside from thunderstorms, some fog and low clouds may occur overnight into Thursday morning, especially in valleys. Confidence in how this plays out is also rather low, and will depend on where rain occurs and the degree clearing overnight. && .JKL WATCHES/WARNINGS/ADVISORIES... Flood Watch through Thursday morning for KYZ044-050>052-058>060- 068-069-079-080-083>088-104-106>120. && $$ SHORT TERM...HAL LONG TERM...FAGAN AVIATION...HAL