####018003978#### FXUS63 KGRB 121151 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 651 AM CDT Wed Aug 12 2026 Updated aviation portion for 12Z TAF issuance .KEY MESSAGES... - Scattered storms early this morning, with very small chances (10-15%) for additional storms later today. Severe potential is low. Chances for showers and storms have increased on Thursday. - Patchy dense fog early this morning near Lake Michigan and the bay. - Chances for heavy rain have increased this weekend, though severe risk remains low. && .DISCUSSION... Issued at 402 AM CDT Wed Aug 12 2026 Near term through Thursday...Certainly more than we bargained for early this morning with a slew of warnings issued as there was just enough lift upon elevated instability and shear over 40 kts. Hail as large as 1.5 inches was observed in eastern Marathon County early this morning. Storms have finally faded in intensity as they shifted into far northeast WI (though small hail and heavy rain may occur), but some thunder to wake people up early this morning in the Green Bay area and over Door County. Rest of today, cannot rule out isolated showers and storms later today into this evening, but chances remain pretty low. Risk for severe weather later today has diminished. On Thursday, trend models started to showing yesterday continues, with pops ramping up to 30-45% as wave drifts through interacting with daytime heating and some building instability. Right entrance region of jet will help enhance activity as well. Dry for Friday with high pressure overhead, then moderate to heavy rain expected this weekend. Showers and storm chances (50-70%) will return to start the weekend as a progressive shortwave trough moves across the region. Precipitable water values increase above the 95th percentile ahead of this system, but seasonably cool temperatures and relatively weak instability look to limit the severe weather risk. Heavy rain risk is there though and WPC has expanded the Slight Risk for excessive rainfall (level 2 of 4) over much of our area south of highway 29. Peak of rain appears to be Saturday afternoon through Saturday evening. LREF probability of 1" from this event is up to 25%, but looking at higher percentiles indicate that the "ceiling" with the rainfall could be over 2 inches. Also decent agreement it would affect the urban areas of the Fox Valley and northeast WI. This will have to be watched as we get closer. Generally drier and seasonable weather is forecast behind the weekend system. Temperatures/Fog...Temperatures will be seasonably warm into Thursday with highs in the lower 80s. Slight cooling into the mid to upper 70s still pegged for Friday into the weekend. Not a big cool down by any stretch. In terms of fog, the overnight storms and blowoff clouds from them did hold down the fog, except near the lakeshore and closer to the bay/Door County. More patchy fog could occur tonight, but signal (especially from MOS guidance) is not as strong as it has looked in the last couple nights. && .AVIATION...for 12Z TAF Issuance Issued at 650 AM CDT Wed Aug 12 2026 Fog will be main focus this morning, especially from MTW to ATW. Vsby will be less than 1/2SM at times, especially closer to the lake. LIFR cigs could linger well into the morning as a weak boundary is just south of this area of fog. Otherwise, conditions will be VFR through tonight. Pop-up showers or storms (15-20%) may occur from northeast WI to the Fox Valley this afternoon into early this evening. Did not include in the TAFs though as coverage looks very sparse. Some fog may occur again tonight, especially at MTW, as light E-SE winds persist. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....JLA AVIATION.......JLA ####018005196#### FXUS61 KCLE 121152 AFDCLE Area Forecast Discussion National Weather Service Cleveland OH 752 AM EDT Wed Aug 12 2026 .WHAT HAS CHANGED... There is a Marginal Risk (Level 1 of 5) for severe weather for Northeast Ohio and Northwest PA today. Some showers and storms could be strong to severe with gusty winds and large hail. && .KEY MESSAGES... 1) Several rounds of showers and storms remain possible through Thursday night. Some showers and storms could be strong to severe in Northeast Ohio and Northwest Pennsylvania this afternoon with gusty winds and large hail. Broader coverage of showers and storms are possible in Central Ohio on Thursday afternoon and evening; locally heavy rain and nuisance flooding is possible. 2) Showers and storms could return as early as Saturday afternoon. Rain coverage will increase into Sunday. && .DISCUSSION... KEY MESSAGE 1... The northwest flow pattern aloft and stalled front to the southwest will continue to dictate the weather across the area through Thursday night. For today, a mid-level shortwave will ripple through the northwest flow this afternoon. This will support a surface trough the will move through the eastern Great Lakes and flare up showers and storms in Northeast Ohio and Northwest PA this afternoon and evening. With better lift in this area and some instability, some storms could be stronger with gusty winds and large hail, but any severe event would be isolated. Further southwest, the shortwave will reinvigorate showers and storms along the front in Indiana and Southwest Ohio. Some of these could spread into Northwest and Central Ohio this afternoon. Any afternoon and evening activity should largely wipe out instability and any large development tonight, but some stray showers may develop over and near the lake with some isentropic lift over the area. For Thursday into Thursday night, the front to the southwest will try to lift north and get into Central Ohio, if not into the southwest portions of the forecast area. One more shortwave will ripple through the northwest flow aloft and allow for more rain and storms to develop. Believe that any storms with any bite to them will be southwest of the forecast area with the better instability. However, any storms will have heavy rain and the potential for localized flooding does exist. High pressure will build from the northwest for Friday, pushing the front and rain chances out of the area. KEY MESSAGE 2... The upper ridge over the Ohio and Tennessee Valleys will recede south a bit on Saturday into Sunday and allow for northwest flow on the northeast side of the ridge. This will allow for a series of shortwaves to move through the region starting as early as Saturday afternoon with most impacts on Saturday night into Sunday. These shortwaves will support shower and storm chances across the area. There is a non-zero chance for strong to severe storms on Sunday with a more organized surface low moving through the eastern Great Lakes region. Temperatures ahead of the low and Sunday convection could get into the mid 80s. && .AVIATION /12Z Wednesday THROUGH Sunday/... Fog will slowly burn off through mid morning, but cigs are trending more pessimistic in much of the region through the afternoon, so expanded the duration of MVFR cigs, except for KERI which should be mainly VFR. Scattered showers and thunderstorms will develop late this afternoon and evening. All sites have the potential to see some brief rain, but maintained the mentions at KTOL, KFDY, KMFD, KCLE, KCAK, and KYNG where chances are highest. KERI may see a shower, but confidence was too low for the TAF. Moving into tonight, VFR should dominate until fog and mist start to form once again. Kept visibilities in the MVFR to IFR range, but it is possible these will be lowered as confidence increases. Light and variable winds early this morning will become SW at 5-10 knots this afternoon and evening before turning light again tonight. Outlook...Non-VFR possible in showers and thunderstorms Thursday into Thursday night. Non- VFR possible again in showers and thunderstorms Saturday afternoon into Sunday. && .MARINE... Quiet conditions will continue on Lake Erie through Thursday as the active frontal boundary slowly shifts south and high pressure attempts to briefly build into the Great Lakes. SW winds of 5-10 knots today will become light and variable tonight and Thursday before turning NE and increasing to 5-15 knots by Friday and Friday night as the high becomes better established. Winds will back to E to SE Saturday and eventually turn S to SW by Sunday as a warm front lifts north, with speeds increasing to 10-20 knots Sunday.' Scattered thunderstorms could bring locally higher winds and waves this evening and again this weekend. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ DISCUSSION...Sefcovic AVIATION...Garuckas MARINE...Garuckas ####018005760#### FXUS62 KMFL 121154 AFDMFL Area Forecast Discussion National Weather Service Miami FL 754 AM EDT Wed Aug 12 2026 ...New AVIATION... .KEY MESSAGES... Updated at 745 AM EDT Wed Aug 12 2026 - A Heat Advisory is in effect today for all of South Florida. - Heat remains the primary hazard through next week. - Highest rain chances today, Thursday, and Saturday. && .SYNOPSIS... Issued at 200 AM EDT Wed Aug 12 2026 Water vapor imagery this morning depicts several areas of enhanced convection within the northern stream flow. These clusters of storms were forced by weak shortwaves advecting around the northern edge of southern CONUS ridging and along a frontal boundary draped across the northern third of the country. As these waves continue on a general NW to SE track, they'll further amplify the eastern CONUS trough as it moves into the western Atlantic. This amplification will fracture the ridge that sprawls the Gulf and SW Atlantic into distinct areas of high pressure over the Gulf/Deep South and across the SW Atlantic. Global ensembles generally agree on this synoptic evolution through Thursday. Beyond Thursday we begin to look at shortwaves moving onto the western US coast and another moving through Quebec. Global ensembles have their greatest differences early in this window when it comes to how far north/south to place the Canadian shortwave, and later in the window with how the western CONUS trough cuts off (or doesn't) and how it eventually merges into the northern stream. Between these two features lies a large and anomalously strong ridge and the shape, movement, and positioning of this ridge will depend a lot on the evolution of the shortwaves. However, South Florida isn't expected to be on the edges of the ridge and instead firmly in its core, and thus the forecast isn't subject much to the current ensemble disagreements. && .SHORT TERM... (Today through Thursday) Issued at 200 AM EDT Wed Aug 12 2026 With the fracturing ridge comes the disruption of the easterly steering flow as well as the continuity of the SAL. Today and tomorrow will likely feature slightly higher PWATs than yesterday and a very weak northerly steering flow. This will generally allow for a little more thunderstorm development along the seabreezes, little inland penetration, and a general southward movement of storms along the seabreeze. Expect the highest rain chances, though, to be across the southern half of South Florida where outflow and storms pile up and move very little due to the weak flow. Even with the most anomalous part of the ridge over the Gulf and Atlantic, column heights and temperatures are expected to still be in at least the top quartile of climatology for this time of year. This means we'll be dealing with both warmer than usual temperatures, and an increase in deep-layer moisture. Thus, a heat advisory is in effect for today for all of south Florida and will likely be needed for at least portions of south Florida again tomorrow. && .LONG TERM... (Thursday night through Tuesday) Issued at 200 AM EDT Wed Aug 12 2026 The extended period becomes a little tricky, not because of the synoptic upper level pattern, but due to the timing of a wave of tropical moisture between pockets of SAL. In general though, global ensembles are within about 12 hours or so of each other with the arrival of the brief period of enhanced tropical moisture. What this ends up looking like is a day of more isolated storm coverage on Friday with at least some SAL influence, increased rain chances on Saturday, and then a prolonged period of drier conditions Sunday into next week. Regardless of rain chances, the deep layer ridging mentioned above will become re-established and anomalously strong for this time of year. Highs in the middle to upper 90s, with heat indices well into Advisory levels are expected for much of the period. && .AVIATION... (12Z TAFS) Issued at 745 AM EDT Wed Aug 12 2026 Generally VFR conditions will prevail through the period. Light and variable winds early morning will turn southeasterly at 5-10 kts by 18Z, with a westerly breeze developing at KAPF. Scattered showers and storms could develop over the interior this afternoon, but confidence regarding impacts to the sites remains low. Light and variable winds again overnight. && .MARINE... Issued at 200 AM EDT Wed Aug 12 2026 Light winds and low seas are expected through the week. Daily wind increases to around 10 knots are expected in the seabreeze zone, as well as a light chop. Shower and thunderstorm activity will remain fairly isolated and mostly limited to the morning hours for the east coast and the evening for the Gulf. && .PRELIMINARY POINT TEMPS/POPS... Miami 93 79 93 81 / 50 10 30 0 West Kendall 93 77 92 77 / 60 10 40 0 Opa-Locka 94 79 93 80 / 60 10 40 0 Homestead 93 79 92 79 / 40 10 30 0 Fort Lauderdale 92 80 91 82 / 40 10 30 0 N Ft Lauderdale 93 79 92 81 / 50 10 30 0 Pembroke Pines 93 79 92 81 / 50 10 30 0 West Palm Beach 94 78 93 79 / 60 10 40 0 Boca Raton 92 78 92 81 / 60 10 40 0 Naples 91 77 92 78 / 30 10 40 10 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...Heat Advisory from noon today to 7 PM EDT this evening for FLZ063-066>075-168-172>174. AM...None. GM...None. && $$ SHORT TERM...Harrigan LONG TERM....Harrigan AVIATION...ATV ####018004817#### FXUS63 KMPX 121153 AFDMPX Area Forecast Discussion National Weather Service Twin Cities/Chanhassen MN 653 AM CDT Wed Aug 12 2026 .KEY MESSAGES... - After a dry day today, scattered thunderstorms can be expected for western through southern Minnesota late tonight into Thursday morning. There is a Marginal (level 1 of 5) Risk that a few storms may be severe. - Widespread steady rainfall is likely Friday night through Saturday. - Temperatures remain warm today then go on a cooling trend through the weekend into early next week. && .DISCUSSION... Issued at 404 AM CDT Wed Aug 12 2026 The wavy west-to-east quasi-stationary front referenced in previous discussions sill remains draped over the Central Plains into the mid-Mississippi River Valley and southern Great Lakes. Weak high pressure remains to the north of this front, essentially sitting atop MN/WI through the day today. This will result in dry but continued warm conditions today with highs into the 80s area- wide with a mix of sun and clouds. Clouds increase tonight as a low- level trough feature, emanating from a low pressure center along the front over the Plains, extends northeast into the Upper Midwest. Once again, enhanced low-level nocturnal jetting interacting with this trough within a continued moist environment (low 70s dewpoints again expected in far western into far southern MN) will spark off scattered showers/thunderstorms from this evening through daybreak Thursday morning. The focus area of convection will be far western through far southern MN, in closer proximity to the omnipresent surface front and its associated trough. Storms look to develop in eastern SD and drive southeast, potentially in enough of an organized fashion where a few storms could be strong to severe late tonight into early Thursday morning. The SPC SWODY1 does a good job of focusing in the Marginal Risk of that potential, while also indicating that the better chances for higher concentration/intensity of storms will be to the south of the WFO MPX coverage area. A small airmass change looks to occur starting on Thursday as northwest flow takes a better hold over the region and modified colder Canadian high pressure makes inroads from the northwest. This will start a period of highs dropping into the 70s area- wide and lows in the 50s outside of the Twin Cities metro (near 60 within). There is decent agreement on an organized area of low pressure arriving from the southwest Friday into Saturday, dragging a slug of moisture from the Deep South into the Upper Midwest as it arrives. This looks to result in fairly widespread rainfall from late Friday through much of Saturday in the form of more stratiform rain rather than convection. That said, model guidance has tweaked down the overall QPF of the system, ranging from around a half inch in the Twin Cities metro to closer to an inch near the IA border and into southwest WI from Friday through Saturday. Still not expecting much in the way of thunderstorm activity but a few embedded t-storms are certainly possible. Temperatures overall look to remain fairly steady from late this week into early next week, with the north-central CONUS remaining under the influence of northwest flow. There are still some signs of a western ridge developing late next week which could result in an appreciable warming for the Upper Midwest. However, overall blended guidance through the next 7 days starts out with temperatures above normal today then dropping slightly below normal from Friday through the middle of next week. && .AVIATION /12Z TAFS THROUGH 18Z THURSDAY/... Issued at 634 AM CDT Wed Aug 12 2026 All sites expected to run VFR through this duration, but chances increase late tonight through early morning Thursday (particularly for western-southern MN) for convection to reach southwest MN from eastern SD. At this point, have added PROB30 mention to AXN-RWF-MKT for MVFR SHRA, but there is still the possibility of IFR TSRA but confidence is too low to include at this point. Winds still light throughout, from an easterly direction if anything. KMSP...Maintained a dry TAF but there is low probability of having SHRA/TSRA potentially moving near MSP close to 12z Thursday morning. Will let later TAFs address this possibility. /OUTLOOK FOR KMSP/ FRI...VFR, -SHRA/MVFR likely late. Wind SE 10-15 kts. SAT...-SHRA, chc MVFR/IFR. Wind SE 10 kts shifting to W. SUN...VFR. Wind NW 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...JPC AVIATION...JPC ####018005471#### FXUS66 KLOX 121154 AFDLOX Area Forecast Discussion...UPDATED National Weather Service Los Angeles/Oxnard CA 454 AM PDT Wed Aug 12 2026 .SYNOPSIS...11/1147 PM. A cooling trend will continue through Thursday, with cooler than normal temperatures expected across the area into the weekend. There is a chance of mountain and occasional lower elevation convection through at least Wednesday night. More robust marine layer cloud coverage is likely this week, however, higher clouds may disrupt the formation of the marine layer at times. && .SHORT TERM (TDY-FRI)...12/1214 AM. Troffing will set up over the west coast today and will continue through Friday. Hgts will fall to 584 dam today and then to 582 dam Thursday. At the sfc there will be mdt-stg onshore flow both to the north and east. Most of the coast will wake up to low clouds this morning with some patchy dense fog across the Central Coast. Skies otherwise will be partly to mostly cloudy as plenty of mid and high level clouds drift overhead. There will be enough low level moisture to allow for a chc of TSTMs over the mtns esp the northern VTA county ones. A small vort lobe will drift over SBA/SLO counties and will bring a chc of showers/TSTMs to those areas as well. Max temps will drop 4 to 8 locally 10 degrees as the marine layer, onshore flow, cloud cover and lowering hgts all conspire together. Most max temps will end up about 6 degrees under normals. On Thursday the SW flow from the trof will bring enough drying to eliminate the convective threat. The onshore flow and troffing aloft will gin up a pretty robust marine layer cloud deck that will cover most of the csts and will xtnd into the vlys. Clearing will be slower than normal and some beaches may only see limited clearing. Another 2 to 4 locally 6 degrees of cooling will bring max temps that are 2 to 4 degrees blo normals across the csts and a whopping 5 to 10 degrees across the vlys. Vly highs will only be in the upper 70s to mid 80s. Not much change is slated for Friday and the day should greatly resemble Thursday. The onshore push to the east will top out near every afternoon. This strong push will generate gusty winds across the Antelope Valley and its foothills. There will be a 20-30 percent chc of low end wind advisories each afternoon. .LONG TERM (SAT-TUE)...12/246 AM. Good agreement with all of the medium range mdls. The west coast trof will persist through Saturday with hgts rising to 588 dam. The trof will then be pushed to the west by a powerful upper high that spans most of the southern portion of the CONUS. Srn CA will then be under flat dry SW. Hgts will climb to 592 dam. At the sfc the mdt to stg onshore flow to the east will continue but the onshore push to the north will weaken substantially and might even be offshore by Tuesday or Wednesday. The weather will be benign through the period. There will be plenty of night through morning low clouds and fog across the csts. Due to the rising hgts the marine layer will be shrunk to under a 1000 ft which should keep it out of the vlys. Skies, otherwise, will be mostly clear. The weakening onshore flow to the north will also lessen the amount of coastal low clouds early next week esp if the offshore flow develops. Gusty but still sub-advisory levels winds will continue across the Antelope Vly. Temps will begin to warm on Saturday. Look for 2 to 4 degrees of warming on Saturday and Sunday and 1 to 2 degrees each day Monday and Tuesday. Even with the four days of warming max temps Tuesday will remain 2 to 4 degrees blo normal. && .AVIATION...12/1153Z. At 0828Z at KLAX, the marine layer was 1600 feet deep. The top of the inversion was near 3400 feet with a temperature of 23 C. High confidence in TAFs for KPRB, KPMD and KWJF. Moderate confidence in TAFs for KBUR and KVNY with a 30 percent chc of no cigs aft 13/06Z. Moderate confidence in TAFs for KSMX and KSBP. VFR conds may arrive +/- 60 minutes from fcst time. Moderate confidence in the remainder of TAFs cigs may vary between 008 and 012. VFR conds may arrive +/- 90 minutes from fcst time. KLAX...Moderate confidence in TAF. VFR conds may arrive as late as 1930Z. No significant east wind component expected. KBUR...Moderate confidence in TAF. There is a 30% chance of no cigs aft 13/06Z. && .MARINE...12/255 AM. High confidence that conditions will remain below Small Craft Advisory (SCA) across all of the southwestern California coastal waters through at least Friday night. However, localized gusts near 20 kt are possible each afternoon and evening off the coast of Long Beach through at least Thursday night. Patchy dense fog are possible on the Central Coast each morning. There is also a 5-10% chance of showers or a thunderstorm over the coastal waters through Wednesday. && .LOX WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory in effect until midnight PDT tonight for zones 349-350-354-362-366. (See LAXCFWLOX). PZ...NONE. && $$ PUBLIC...Rorke AVIATION...Rorke MARINE...Phillips/RK SYNOPSIS...Lewis/Phillips weather.gov/losangeles Experimental Graphical Hazardous Weather Outlook at: https://www.weather.gov/erh/ghwo?wfo=lox