####018006172#### FXUS62 KFFC 101754 AFDFFC Area Forecast Discussion National Weather Service Peachtree City GA 154 PM EDT Fri May 10 2024 ...New 18Z Aviation Discussion... .UPDATE... Issued at 1140 AM EDT Fri May 10 2024 Forecast remains on track. High cloud debris continues to thin and push E. Lingering stratocumulus and cumulus clouds continue to produce partly to mostly cloudy skies across much of the area (thickest clouds from N of CSG to N of MCN). Drier air at cloud level will eventually allow these clouds to thin from the N, but occasionally mostly cloudy skies will remain possible S of a cold front which is sinking S thru the area. Isolated showers and thunderstorms remain possible along and S of the front this afternoon, with the best chances near and S of MCN. /SEC && .SHORT TERM... (Today through Saturday) Issued at 323 AM EDT Fri May 10 2024 Key Messages: - Thunderstorms will bring widespread rainfall to central Georgia this morning. - A frontal passage today will result in cooler and less humid weather on Saturday. Today and Saturday: The initial weather concern today will be an MCS moving out of Alabama. General thinking is that the MCS will track eastward this morning along an outflow boundary and instability gradient left by prior convection (from yesterday and overnight). This boundary currently stretches from south central Alabama into southern Georgia and is nearly stationary. Assuming storms follow this boundary, the greatest potential for severe weather though noon today should be over southern Georgia and the Florida Panhandle. Any storms in central Georgia should be elevated and working with an atmosphere that has been chewed up and spit out by several rounds of thunderstorms over the last 24 hours. Thus the severe weather potential for places like Columbus and Macon should be towards the lower end of the scale. The primary hazards with any stronger storms would be damaging wind gusts or hail. Thunder could occur as far north as Atlanta this morning, but severe weather is not anticipated due to a lack of appreciable instability. An airmass shift will occur this afternoon as a cold front sweeps through Georgia. The front will announce it presence via the arrival of gusty northwest winds this afternoon. Sustained winds between 10 and 20 mph are expected along with peak wind gusts in the 25 to 35 mph range. Drier air will move in behind the front and this will bring any lingering precipitation in central Georgia to an end this evening. By Saturday morning a cooler and drier airmass should be firmly in place across the Southeast. This will set the region up for a very pleasant start to the weekend, with high temperatures in the mid to upper 70s and low humidity (35-45%). Northwest winds should continue in the region on Saturday. While the winds will decline some compared to today, peak gusts in the 20 to 25 mph range are still anticipated in the afternoon. Albright && .LONG TERM... (Saturday night through Thursday) Issued at 323 AM EDT Fri May 10 2024 Key Messages: - Quiet weather will continue in the region Sunday and Monday. - Two additional rounds of widespread rainfall are probable in Georgia between Tuesday and next weekend. The Outlook for Next Week: Next week should begin with a surface high and upper level ridging over the Southeast. Due to this pattern Sunday and Monday should feature dry weather and average to slightly below average high temperatures. Atlanta can expect a high in the upper 70s on Sunday and a high near 80 on Monday. Looking further into the upcoming week it looks like the Southeast will be in for at least two more rounds of widespread rainfall. Both the GEFS and EPS show consistent signals for a round of rainfall Tuesday into Wednesday followed by a second round of precipitation next weekend. The time of year and strength of the troughs driving both rounds of precipitation suggest at least some potential for stronger thunderstorms with both events. Some localized flooding concerns could also develop by next weekend, and it is worth noting that multiple GEFS and EPS members are indicating rainfall totals of 2 to 4 inches with second potential rain event. Albright && .AVIATION... (18Z TAFS) Issued at 146 PM EDT Fri May 10 2024 Cold front currently bisects the area, with the thickest CU field along and S of the front still affecting MCN and CSG. CU N of the frontal surface has occasionally gone BKN as well, both from the delayed drying at cloud level and the flattening of cloud elements beneath a subsidence inversion. Expect continued thinning and lifting of the low cloud deck through the remainder of the afternoon. Thicker clouds across TN may make it S of the state line as they continue to slowly erode, but don't think another cig will make it to the N terminals. However, did include a prolonged period of SCT at RYY. A few showers remain possible near MCN for the next several hours (included VCSH). Any tstm activity that can get going across S central GA should be SE of the terminal. Gusty NW winds should decouple in the early evening. //ATL Confidence...18Z Update... High on all elements. SEC && .PRELIMINARY POINT TEMPS/POPS... Athens 52 77 55 80 / 0 0 0 0 Atlanta 55 77 57 79 / 0 0 0 0 Blairsville 46 70 48 73 / 0 0 0 0 Cartersville 50 77 52 79 / 0 0 0 0 Columbus 57 80 59 83 / 0 0 0 0 Gainesville 53 76 55 79 / 0 0 0 0 Macon 56 79 57 82 / 0 0 0 0 Rome 50 77 53 80 / 0 0 0 0 Peachtree City 53 77 55 80 / 0 0 0 0 Vidalia 59 79 60 83 / 10 0 0 0 && .FFC WATCHES/WARNINGS/ADVISORIES...None. $$ SHORT TERM...SEC LONG TERM....Albright AVIATION...SEC ####018005433#### FXUS62 KILM 101755 AFDILM Area Forecast Discussion National Weather Service Wilmington NC 155 PM EDT Fri May 10 2024 .SYNOPSIS... Showers and thunderstorms are likely later today ahead of an approaching cold front. The front crosses the area tonight, bringing much cooler and drier air for the weekend and start of next week. Rain chances increase next Tuesday. && .UPDATE... Showers and thunderstorms are developing along a cold front draped across central NC and west-central SC. Expect storms to develop into an organized structure this afternoon and move south and east toward the coast this evening. A Severe Thunderstorm Watch has been issued through 9 PM. && .NEAR TERM /THROUGH TONIGHT/... Convective debris mid/hi clouds will overspread the area through the morning from MCS activity to the south and southwest. Guidance is largely consistent in keeping this precipitation south of the CWA, with only a small chance of a shower sneaking in before noon. The better chance for storm development today will be in association with a shortwave approaching from the northwest, which will drive a cold front through the area late this afternoon, coincident with peak heating. The amount of destabilization, and therefore the potential for strong to severe storm development, will be dependent in large part on how much the cloud cover will interfere. If moderate destabilization materializes, which seems reasonable in a 18Z-22Z window, deep layer shear would be supportive of some storms producing hail/damaging wind gusts. SPC has upgraded the Day 1 outlook from marginal to slight risk for the northern 2/3 of the ILM CWA. Convection will come to an end this evening as the cold front pushes offshore after 00Z. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A dry and somewhat cooler weekend is in store as the aforementioned cold front races offshore. High temps in the mid 70s Saturday nudge up to around 80 for Sunday as a mid-level trough shifts offshore and weak sfc high pressure is centered off to the south. Mostly sunny/clear skies will be the norm with deep-layer moisture lacking. && .LONG TERM /MONDAY THROUGH FRIDAY/... Next week will feature a return to wet weather as guidance continues to be in good agreement on an upr-level trough approaching from the west with a broad area of low-level WAA ahead of it. Monday should be dry, before rain chances increase from S to N Monday night and moreso Tuesday as precipitable water values climb sharply. With high confidence in the rain, PoPs are now in the 70-80% range Tuesday. Some uncertainty remains on how quickly the trough moves through, with the 00Z GFS noticeably quicker than the 00Z ECMWF. Still, with transient shortwaves embedded in the flow will maintain at least low PoPs through the end of the long term period, with high temps running slightly above climo. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... Cold front will drop southeastward across the area late this afternoon into this evening. Expect thunderstorms to impact terminals from west to east from 21Z to 01Z this evening. Thunderstorms will bring the potential for damaging winds (winds in excess of 30 knots) and large hail. Expect IFR VIS in heavy rain and thunder in addition to strong winds. Some lingering showers may exist after the initial line of thunderstorms. Once the cold front moves offshore, VFR will return to all terminals as precip comes to an end. Clear skies, VFR, with north winds on Saturday. Extended Outlook...A cold front moves through Friday night, which dries out the atmosphere. Widespread VFR should take over Friday night through Monday. Flight restrictions may occur Monday night into Tuesday with the next weather system moving in. && .MARINE... Through Tonight: Surface low pressure along the Mid Atlantic coast this morning, combined with high pressure well off the SE CONUS, is producing a moderate gradient across the coastal Carolina waters. The offshore trajectory will limit seas near shore to around 2 ft, with 3-5 footers a few miles out. WSW winds will continue most of today ahead of a cold front, which will move off the coast early this evening. Wind speeds of 15 kt with gusts to 20 kt should be the rule today, shifting to the NW just after sunset. Scattered to numerous thunderstorms are expected to develop ahead of the front, and some may become strong to severe. High pressure will begin to build in overnight, producing northerly winds on the order of 15 kt gusting to 20 kt. Saturday Through Tuesday: Generally benign marine conditions this weekend into early next week with weak sfc high pressure in the vicinity. Wind directions variable through Monday, with speeds up to 10-15 kt. Significant wave heights steady at 2-3 ft, with a weak easterly swell present. Conditions then start to deteriorate Tuesday ahead of the next low pressure system, with southerly flow increasing to ~20 kt and seas up to 5-6 ft. && .ILM WATCHES/WARNINGS/ADVISORIES... NC...None. SC...None. MARINE...None. && $$ SYNOPSIS...ILM UPDATE...21 NEAR TERM...CRM SHORT TERM...MAS LONG TERM...MAS AVIATION...21 MARINE...MAS/CRM ####018003084#### FXUS62 KTBW 101755 AFDTBW Area Forecast Discussion National Weather Service Tampa Bay Ruskin FL 155 PM EDT Fri May 10 2024 .DISCUSSION... A MCS that fueled storms over north Florida (including Levy county) this morning has continued to shift eastward, with just a few storms remaining here and there across the peninsula. The forecast for tonight does include a chance for another round of showers and storms as a boundary drops southward across the area, with timing generally after midnight and shifting southward through daybreak. The boundary will be across the southern part of the peninsula for the rest of Saturday, with a chance for a few showers over the southwest Florida region only as drier air moves in to the north. High pressure briefly builds in over the southeast for Sunday, but is then quickly shunted eastward by another system moving through the central U.S. Our local low-level winds will turn southeast in response to the high moving away, allowing moisture to rapidly return to the region early next week. Another frontal boundary will approach the area late Tuesday before eventually stalling somewhere across the central peninsula on Wednesday. This overall setup will keep rain chances in the forecast each day next week, though chances will lower some late in the week as the boundary dissipates. && .AVIATION... (18Z TAFS) Mainly VFR conditions are expected through the rest of the day. Rather tricky forecast, but current thinking is that thunderstorm chances remain low until overnight, when most sites should see vicinity storms. MVFR cigs are also possible as the boundary sinks southward, and those will likely linger until mid-morning or so, with VFR returning thereafter. && .MARINE... Southwest winds today will turn northwest tonight as a frontal boundary moves through the area. Winds then quickly turn east and then southeast Sunday into early next week, increasing near exercise caution levels for Tuesday as another boundary approaches the region. Rain chances remain low for the weekend, but will increase for next week ahead of the next front. && .FIRE WEATHER... Drier air moves into the region for the weekend, especially on Sunday, but no Red Flag conditions are expected. Low-level moisture then increases for next week, with no further concerns. && .PRELIMINARY POINT TEMPS/POPS... TPA 78 89 71 90 / 20 0 0 0 FMY 77 90 69 92 / 10 30 0 0 GIF 75 94 67 92 / 20 10 0 0 SRQ 76 89 69 90 / 20 10 0 0 BKV 70 90 62 91 / 30 0 0 0 SPG 79 88 74 88 / 30 10 0 0 && Sea Breeze Thunderstorm Regime For Friday: 5 Sea Breeze Thunderstorm Regime For Saturday: 8 For additional information on sea breeze regimes, go to: https://www.weather.gov/tbw/ThunderstormClimatology && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ 05/Carlisle ####018006645#### FXUS66 KOTX 101756 AFDOTX Area Forecast Discussion National Weather Service Spokane WA 1056 AM PDT Fri May 10 2024 .SYNOPSIS... Temperatures today through the weekend warm to the highest values of the season so far, with highs reaching the 80s and a few areas the lower 90s. The weather pattern for early next week is uncertain, however a cooling trend is likely with increasing clouds, and a small chance of precipitation for the Cascade Crest, northeast Washington, and the northern half of the Idaho Panhandle. && .DISCUSSION... Friday through Sunday: Dry and quiet weather will continue through Saturday as a large ridge sits over the Pacific Northwest and a closed upper level low sits over Great Basin. This rex block pattern will keep the ridge nearly stationary over the northwest today and tomorrow. This will allow temperatures to warm into the upper 70s to low 90s today and tomorrow, which are about 10 to 20 degrees above average for this time of the year. Those who are sensitive to heat or not yet acclimated to this type of heat should plan to take some extra precautions if planning to spend time outside this weekend. Water temperatures for lakes and rivers across the region are on average in the upper 40s and low 50s. Please be mindful of this if planning to spend some time near or on the water. Hypothermia and loss of muscle control happens very quickly when swimming in water temperatures this low. The ridge will begin to weaken and shift eastward late Saturday into Sunday as a shortwave approaches the northwest. The cross-Cascade pressure gradient will begin to tighten Saturday afternoon and evening as the flow shifts onshore, resulting in breezy winds through the Cascade valleys. As the shortwave nears Sunday, the Cascade valleys will experience some marginal cooling, but temperatures will still be very warm regionwide. Winds will pick up region wide on Sunday. Current forecast has the strongest gusts across the lee of the Cascades from the Okanogan Valley, the Waterville Plateau, and the western Columbia Basin. Following the stretch of very warm and dry weather, these winds will bring an increased risk for quick moving dead grass and brush fires. /vmt Sunday night to Thursday: The ridge flattens near the start of the week, with a shortwave trough migrating through before there is an opportunity for the ridge to rebound toward the middle part of next week. However by mid to late week guidance continues to diverge, showing either an amplifying ridge or another wave coming in. First between Sunday night and Tuesday look for variable cloud cover, with breezy conditions. Limited shower chances will be found near the Cascade crest and Canadian border Sunday night, expanding over more of the northern WA and ID Panhandle mountains for Monday and Tuesday. The best chances, overall, appear to be Monday. Some guidance even expands some potential over Spokane/C’dA and Palouse. I give a nod to ensembles painting a 10-40% chance of measurable precipitation by adding some slight chances around the Spokane/C’dA area; I held off on the Palouse as the ensembles probabilities are more borderline there. There will also be limited t-storm chances especially on Monday afternoon and evening, with the shortwave encountering a projected 200-400 J/kg of SBCAPE. However Sunday evening may also see a few embedded t-storms. These chances will largely be toward the NE WA and N ID Mountains. As for winds, the incoming shortwave will bring some of the stronger winds near the Cascades expanding out into the western Columbia Basin Sunday night. Sustained winds between 15-25 mph will be possible with gusts up to about 40 mph. Elsewhere winds will increase some with gusts near 15-20 mph. Broader breezy conditions will be found Monday and Tuesday, though the extremes are more washed out by then as the primary front will have shifted through leaving sustained winds 10-15 mph and gusts of 20-25 mph. Heading into Wednesday and Thursday the model disagreement starts to impact the forecast. If a stronger ridge returns it will be drier and if a trough dominates it will be wetter. A middle ground approach shows some slight to chance PoPs around the mountain zones and eastern third of WA and lower ID. It will also remain potentially breezy, but marginally. Temperatures drop down Monday into Tuesday with the trough in the region, meaning highs in the upper 60s and 70s, with a few areas near 80 in the deeper Columbia Basin. Wednesday into Thursday forecast temperatures are held near persistence from Monday and Tuesday. However if the ridge manifests stronger it could be warmer and if a deeper trough comes in it could be cooler. Models show about a 20 degree range in potential highs by Thursday. For example, most recent guidance in Spokane shows it could be as cool as 65 or as warm as 81. /Solveig && .AVIATION... 18Z TAFS: Widespread VFR conditions are expected through the TAF period as high pressure builds over the region. All winds will be 10kts or less. Saturday afternoon we will see an increase in winds, but nothing significant. FORECAST CONFIDENCE AND/OR ALTERNATE SCENARIOS: There is very high confidence for VFR conditions across all TAF sites. ----------------------- Confidence descriptors: Low - Less than a 30 percent chance Moderate - 30 to 70 percent chance High - Greater than a 70 percent chance For additional probabilistic information for NWS Spokane airports, please refer to the Aviation Dashboard on our webpage: https://www.weather.gov/otx/avndashboard && .PRELIMINARY POINT TEMPS/POPS... Spokane 80 49 82 53 83 53 / 0 0 0 0 0 0 Coeur d'Alene 79 49 80 52 80 51 / 0 0 0 0 0 0 Pullman 76 48 79 51 78 51 / 0 0 0 0 0 0 Lewiston 81 54 85 56 86 56 / 0 0 0 0 0 0 Colville 82 47 83 48 83 48 / 0 0 0 0 0 10 Sandpoint 77 49 79 51 78 50 / 0 0 0 0 0 10 Kellogg 76 52 77 54 77 53 / 0 0 0 0 0 10 Moses Lake 86 52 89 52 89 53 / 0 0 0 0 0 0 Wenatchee 84 58 88 58 86 55 / 0 0 0 0 0 0 Omak 86 53 89 53 88 52 / 0 0 0 0 0 0 && .OTX WATCHES/WARNINGS/ADVISORIES... ID...None. WA...None. && $$ ####018007175#### FXUS61 KBUF 101757 AFDBUF Area Forecast Discussion National Weather Service Buffalo NY 157 PM EDT Fri May 10 2024 .SYNOPSIS... Unfortunately...cool and generally unsettled weather will remain in place through the weekend. Thats not to say that the next couple of days will be a washout...as there will be frequent rainfree periods as well. Daytime temperatures this weekend will be a solid 5 degrees BELOW typical mid May levels. While the mercury will TRY to get back towards normal for the first half of next week...there will still be a fair amount of showers around. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Rainy weather will be in place across much of our forecast area for the rest of the afternoon...particularly over the Finger Lakes region...as we will remain on the northern periphery of a poorly organized storm system over the Mid Atlantic region. Lift from this feature will be enhanced by a shortwave trough that will sag south through the region. The whole area will not be adversely impacted though...as enough dry air in the mid levels will allow for some sunshine from Niagara county to near Rochester...and also across parts of the North country. The aforementioned shortwave trough will push the weak area of low pressure further away from our region tonight...while a progressive shortwave ridge will cross the Lower Great Lakes. This scenario will be accompanied by a wedge of dry mid level air that will bring an end to the rain in most areas while promoting some clearing...mainly over the western counties. A robust shortwave and attendant sfc low will dive southeast across the Upper Great Lakes on Saturday. A swath of deep moisture ahead of this system will push across the western counties during the midday and afternoon...then across the Eastern Lake Ontario region late in the day and Saturday night. The resulting lift supplied by moderate hgt falls...low level convergence and being in the proximity of the left front quad of a nominal 90kt H25 jet with this scenario will prompt a renewal in shower activity as the day matures. There could even be a thunderstorm over the western counties. The most widespread and persistent shower activity will be over the western counties during the afternoon. Dry weather with some sunshine can even be expected for the Finger Lakes before conditions deteriorate. It will remain cool...as temperatures on Saturday will top out within a few degrees of 60. Showery weather will then linger through much of Saturday night...as the core of a H5 low with its -24c temps will pass directly across our region. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Shower will slowly diminish from west to east Sunday as the mid- level low exits off to our southeast. Overcast skies will then overtime begin to break up revealing some sunshine by late Sunday afternoon. Otherwise...a cool day will be felt with highs in the upper 50s across the higher terrain to low 60s. Sunday night...shortwave ridge briefly builds in which should deliver dry weather for much of the overnight hours. The next feature of interest will be an occluded front approaching the eastern Great Lakes from the northwest early Monday morning. This boundary will slowly ooze into the forecast area with showers becoming 'likely', and the potential for some rumbles of thunder. It will not be quite as cool Monday with temperatures peaking in the upper 60s to low 70s. Monday night...this is where the forecast gets a bit more murky in regards to the progression of the front through the region. It will all depend on the interaction of a mid-level low spinning over the Midwest and another low located over James Bay. At this point...there are various model solutions ranging from very wet(GFS) weather to it turning progressively drier by the middle of the week. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A closed mid-level low centered over the Hudson Bay Tuesday morning will gradually rotate eastward into Wednesday. Meanwhile, ridging to the west across the Upper Midwest and western Great Lakes Tuesday night will build across the remainder of the Great Lakes into Friday morning before the next trough dives southeast across the Central Plains Friday. Overall, with the mid-level closed low to the north of the area Tuesday, its associated surface low over Quebec will support a cold front to finish pushing southeast across the area Tuesday, supporting widespread rain and a few rumbles of thunder to pass across the area. Chances for showers will then continue across the area Tuesday night through Wednesday due to the troughing overhead. As the aforementioned mid-level ridging pushes east across the Great Lakes, associated surface high pressure will also move into the eastern Great Lakes, resulting in a period of dry weather Wednesday night thorugh much of Thursday. The next chance for showers will return Thursday night through Friday as warm front approaches the area. Expect a gradual warming trend throughout much of next week, with subtle warming each day. By the end of the week the temperatures will have rebounded to slightly above normal. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... While VFR weather will be found throughout the region through at least midday Saturday...there will be some rain to contend with. For the rest of the afternoon...the area of steady rain will be focused on the Finger Lakes area. This area of weather will taper off during the course of tonight with only a couple showers possible east of Lake Ontario after midnight. VFR conditions Saturday morning will deteriorate during the midday and afternoon...as showers will redevelop...particularly over the western counties. The increasing coverage of the showers and possible thunderstorms will be accompanied by CIGs that will lower to MVFR levels. Outlook... Saturday night...MVFR cigs with showers gradually diminishing in coverage. Sunday...VFR to MVFR CIGS with scattered showers. Monday and Tuesday...VFR/MVFR with the likelihood for showers and possible thunderstorms. Wednesday...Improving conditons with precipitation exiting. && .MARINE... Gentle to moderate north to northeasterly breezes (less than 15 knots) will continue on the Lakes, maintaining some light, to at times moderate chop through today. However, there are no Small Craft conditions forecast. Mainly light, variable winds (less than 10 knots) will then be the rule through the most of the weekend, before a more pronounced southwesterly flow (10-15 knots) develops ahead of a warm front approaching from the west toward the tail end of the weekend. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...RSH NEAR TERM...RSH SHORT TERM...AR LONG TERM...EAJ AVIATION...RSH MARINE...JM/TMA ####018004479#### FXUS63 KLSX 101758 AFDLSX Area Forecast Discussion...Updated Aviation National Weather Service Saint Louis MO 1258 PM CDT Fri May 10 2024 .KEY MESSAGES... - The next opportunity for showers and thunderstorms across much of the area is Monday and Monday night. Strong to severe thunderstorms are unlikely. - Generally seasonable temperatures are expected through next week. && .SHORT TERM... (Through Late Saturday Afternoon) Issued at 342 AM CDT Fri May 10 2024 Upper-level northwesterly flow will remain in place over the Mid- Mississippi River Valley through Saturday night, navigated by a pair of troughs accompanied by very limited chances of rain. The first trough is already passing overhead this morning, but associated isolated to scattered showers have dissipated as they entered northeastern MO and west-central IL as marginal instability decreased and low-level forcing remains negligible. Therefore, dry conditions will prevail today as shortwave ridging briefly builds in the wake of the trough. With a seasonably cool airmass in place behind last evening's cold front and prevalence of scattered to broken stratocumulus/cumulus, temperatures are expected to be slightly below average today with high temperatures in the mid-60s to low-70s F. The next trough will arrive tonight, forcing a weak cold front through the CWA. The strongest large-scale ascent and frontal moisture convergence will pass to the north and northeast of the CWA, but enough forcing may available for isolated showers along the front in northeastern MO and west-central/south-central IL. Post- frontal CAA will be short-lived and insolation will be abundant on Saturday, resulting in a warming trend through Saturday with temperatures near average. Pfahler && .LONG TERM... (Saturday Night through Thursday) Issued at 342 AM CDT Fri May 10 2024 Global deterministic and ensemble model guidance are in general agreement with an eastward ejection of an upper-level closed low from the Rocky Mountains to the Mississippi River Valley on Monday that will both interrupt the northwesterly flow and provide a more robust opportunity for showers and a few thunderstorms. There are differences in the exact structure and timing of the trough along with associated surface cyclone track, but at least a period of showers is expected for most of the CWA between Sunday evening and Tuesday with ensemble model 24-hour probabilities of QPF greater than 0.10" over 80 percent CWA-wide. Probabilities of QPF greater than 0.50" are 40 to 50 percent along and south of I-70, closer to the mean surface cyclone track and associated warm sector with marginal instability and the best chance of thunderstorms. The potential for any strong to severe thunderstorms appears low with probabilities of more than 1000 J/kg of SBCAPE less than 10 percent and deep-layer wind shear not progged to be particularly strong. Ahead of the trough, low-level southerly flow is anticipated to warm temperatures to just above average on Sunday, but the impact of clouds and precip on Monday is uncertain with the NBM high temperature interquartile range nearly 10 F. Disparities in global model guidance increase through the rest of next week, especially with the amount of upper-level ridging across the western CONUS, but there is at least a signal for another trough to pass over the Mississippi River Valley Thursday into Friday before differences upstream become a more significant impact. A large portion of ensemble model guidance have showers and thunderstorms in the CWA with this trough at some point in that timeframe. Otherwise, after temperatures cool again to slightly below average again by Tuesday, but increasing spread in the NBM interquartile range thereafter demonstrates a question in whether temperatures warm to average or above average. Pfahler && .AVIATION... (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1256 PM CDT Fri May 10 2024 VFR conditions are expected with a light northwest wind becoming southwest overnight ahead of a cold front that will bring the wind back around to the northwest on Saturday. CVKING && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX ####018004535#### FXUS63 KILX 101758 AFDILX Area Forecast Discussion...Updated Aviation National Weather Service Lincoln IL 1258 PM CDT Fri May 10 2024 .KEY MESSAGES... - In the Monday-Tuesday timeframe, there is a 20-30% chance of greater than 0.75" of rainfall in 24 hours. Should this occur, one impact would be additional runoff into area rivers already running high. && .UPDATE... Issued at 957 AM CDT Fri May 10 2024 Mid level water vapor satellite imagery shows an upper trough sinking southeast across the Ohio Valley and towards the Appalachians this morning. As a shortwave ridge builds into the Prairie State in its wake, mid levels will dry and become increasingly stable this afternoon, though steep lapse rates off the surface will provide a shallow layer of stout instability favoring continued cu development (HREF probs for low clouds remain 40-60% through the evening). Can't rule out a couple sprinkles with this activity, though most, if not all, precip falling from the more robust towering cu should evaporate through the dry "inverted V" below the LFC. A better chance (> 30% north of a Macomb to Paris line) for showers will arrive tonight as a compact upper trough and associated trailing cold front pass through the region. Bumgardner && .DISCUSSION... Issued at 237 AM CDT Fri May 10 2024 An upper level wave is diving southeast across IL this morning. There have been a few showers associated with this wave as it traversed IA and moved into northwest IL, but the latest high res models indicate these showers won't make it deep into central IL. We will see brief upper ridging this afternoon before another upper wave dives southeast into IL tonight in the northwest flow aloft. An associated surface low will dive southeast across the Great Lakes with an accompanying cold front passing through IL Friday night. We'll see a chance for showers with this system Friday night, but instability looks rather weak. Believe thunder chances will be rather slim as MUCAPEs look to be less than 100 J/kg according to the HREF mean. Expect benign northwesterly flow aloft for the weekend. We'll have breezy northwest winds on Saturday with a surface ridge of high pressure moving through the area Saturday night. By Sunday night, an upper low will be passing to the east across Ontario with a southern stream upper low approaching to the southwest. Precipitation chances increase across IL from this southern system Sunday night, with some moderate chances for thunder expected as MUCAPEs are as high as 500 J/kg in west-central IL. The upper low will slowly make its way east across the mid MS River Valley on Mon/Tue and the track will play a key role in how far north the rain extends. Showers with embedded thunderstorms are expected for the start to the week, with the southern half of IL having the best chance for measurable rainfall. Right now, the rainfall ensemble mean for Mon-Tue ranges from around 0.25" in Galesburg to 0.75" in Lawrenceville. Models also have a 20-30% chance for 0.75" of rain in 24 hrs in our southern zones, around I-72 and south, which could add some additional runoff to area rivers that are already running high. Sometime in the Wed-Thu timeframe, we'll likely see an upper ridge move into the area once again, providing a break from the precip for at least part of the period. There are model differences in the timing of this ridge, but sometime on Thu or Friday, another upper wave is expected to bring showers and storms back to the region. Stay tuned for updates to this late week system as the picture becomes clearer with subsequent model runs. Knutsvig && .AVIATION... (For the 18z TAFs through 18z Saturday Afternoon) Issued at 1254 PM CDT Fri May 10 2024 Aside from marginal MVFR ceilings around BMI (which should be lifting over the next hour or two), VFR conditions should be predominant throughout the forecast period, barring a brief vis drop with scattered showers overnight. Low VFR ceilings should break up behind the cold front, when a pronounced wind shift (from southwest to northwest) will also occur. Northwest winds will increase, gusting frequently over 20 kt, by mid to late Saturday morning when surface heating aids in mixing. Bumgardner && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ ####018005190#### FXUS63 KGRB 101758 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 1258 PM CDT Fri May 10 2024 Updated aviation portion for 18Z TAF issuance .KEY MESSAGES... - A quick moving cold front will bring showers and a few storms to the region late this afternoon into this evening. A few storms may contain gusty winds to 40 mph and small hail, but severe weather is not expected. - An unsettled weather pattern will bring intermittent chances of showers and a few thunderstorms this weekend. Severe weather is not expected with any of these thunderstorms, but we will be watching for the potential for strong storms on Sunday. - Due to the recent rainfall, river levels remain elevated. Some rivers may reach or surpass bankfull. && .DISCUSSION... Issued at 348 AM CDT Fri May 10 2024 Short Term...Today...Tonight...and Saturday Lingering showers had finally dissipated, but cloud cover was still prevalent over the southeast third of the forecast area early this morning. Mostly clear skies and light winds over far northern WI had allowed temperatures to drop into the upper 20s to middle 30s where frost/freeze headlines were in effect. A mix of clouds and sun will be found across the region this morning, but increasing clouds and showers will overspread the region from NW to SE as a cold front and potent short-wave trough move through this afternoon and early evening. SBCAPE is weak and confined to our far western counties in the late afternoon and early evening, but 700-500 mb lapse rates of 7-7.5 C/km overspread the forecast area, so isolated to scattered embedded storms are a good bet with the main rain band. Forecast soundings show inverted-v signatures supportive of gusty winds, and low wet-bulb zero heights of 5500-6000 feet indicative of small hail potential with the stronger storms. The main bulk of the precipitation will shift east of the region by mid to late evening, with just a few lingering showers expected over N WI. On Saturday, partly to mostly cloudy skies will prevail, and a slight chance of showers will accompany a short-wave trough, especially in eastern WI. Highs today should be in the lower 60s northwest, and mid to upper 60s southeast, except near Lake Michigan, where highs will only be in the middle to upper 50s. Lows tonight will be in the upper 30s to middle 40s. Highs on Saturday should be in the lower to middle 60s, except middle to upper 50s lakeside. Long Term...Saturday Night Through Thursday Impact potential is greatest during the Sunday afternoon and Sunday night timeframe when a cold front crosses the region near peak heating. Focus of this forecast therefore revolves around precip trends and severe weather potential during this period. Precipitation and Thunderstorm Chances...The weather system moving across the region during this time period continues to have an earlier arrival time. As a potent upper trough digs across northwest Ontario, a warm front will quickly advance across Wisconsin late on Saturday night into Sunday morning. Showers will be possible along the warm front, but little to no instability likely means the thunderstorm threat is low. Thunderstorm parameters turn more interesting on Sunday afternoon and evening when a cold front can interact with a very unstable airmass in the warm sector. The gfs in particular points to robust surface based instability developing on the order of 2000-3000 j/kg although ensemble means are considerably less (up to 1000 j/kg). This discrepancy may be due to an over-zealous moisture profile in which the GFS brings dewpoints in the upper 50s into the region compared to the ensemble means of around 50 degrees. Something to watch for in subsequent forecasts. Deep layer shear of 20-25 kts remains a limiting factor for severe weather. Given the potential for robust instability, think pulse type storms could become strong at times, but the threat of organized severe weather is low. The next chance of precip following this system will arrive in the late Wednesday-Thursday time frame. Temperatures: After a warm day on Sunday (mid and upper 70s), temperatures cool closer to normal (60s) for the rest of the period. && .AVIATION...for 18Z TAF Issuance Issued at 1258 PM CDT Fri May 10 2024 An upper level disturbance and surface front will move across the area during the late afternoon and early evening hours and could bring an hour or two of showers or thunderstorms and MVFR conditions. Wind gusts to 30 knots are possible with any thunderstorms. There could be a period of MVFR ceilings north of a Ironwood to Antigo to Green Bay line late tonight and early Saturday morning, but VFR flight conditions are likely elsewhere. Good flying weather is expected Saturday afternoon through Sunday morning. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kieckbusch/MPC AVIATION.......RDM