####018008491#### FXUS63 KIND 162231 AFDIND Area Forecast Discussion National Weather Service Indianapolis IN 631 PM EDT Fri May 16 2025 .KEY MESSAGES... - Severe Thunderstorms are expected between 5-11PM EDT. - All Severe modes are in play today, including damaging straight line winds, large hail, and tornadoes. The greatest threat looks to be widespread damaging winds south of the I-70 corridor - Warm and humid with highs in the mid to upper 80s. - Cooler and quiet for the weekend, additional precipitation again next week && .MESOSCALE UPDATE... Issued at 617 PM EDT Fri May 16 2025 DEEPER LOW LEVEL MOISTURE HAS REMAINED OVER SOUTHERN INDIANA WITH DEWPTS ABOVE 65F GENERALLY ALONG AND SOUTH OF A LINE FROM SULLIVAN COUNTY INDIANA EASTWARD TO CINCINNATI AREA. NORTH OF THIS LINE, DEWPTS RANGE FROM NEAR 50 AT LAFAYETTE TO THE UPPER 50S/LOWER 60S ALONG THE I-70 CORRIDOR. ALTHOUGH A SLIGHT INCREASE IN LOW LEVEL MOISTURE IS STILL EXPECTED AHEAD OF THE MAIN CLUSTER OF THUNDERSTORMS, THE THREAT FOR TORNADOES APPEARS TO BE FALLING FOR AREAS ALONG AND NORTH OF I-70. HOWEVER IN THESE AREAS THE DEGREE OF DRIER AIR IN THE LOW-MID LEVELS WILL SUPPORT DAMAGING WIND GUSTS UP TO 65 MPH AS THE PRIMARY SEVERE THREAT WITH ISOLATED LARGE HAIL POSSIBLE. THESE STORMS WILL REACH THE WESTERN INDY METRO AREA AROUND 645 PM AND DOWNTOWN INDIANAPOLIS BETWEN 7 AN 715 PM. SOUTH OF I-70...MULTIPLE SUPERCELL THUNDERSTORMS WILL CONTINUE TRACKING EAST-NE ABOUT 45 MPH. THESE STORMS WILL CONTINUE TO HAVE A THREAT FOR ALL HAZARDS, INCLUDING LARGE HAIL, DAMAGING WINDS AND TORNADOES PROVIDED THE MORE UNSTABLE ENVIRONMENT AND STRONGER LOW LEVEL SHEAR /0-1 KM SRH AROUND 200 M2/S2/. && .SHORT TERM (This afternoon through Saturday)... Issued at 1152 AM EDT Fri May 16 2025 Update for upcoming severe event: Key Messages: - Widespread thunderstorms with numerous severe thunderstorms expected between 5PM and 11PM EDT - All severe weather hazards possible, but highest confidence in destructive wind gusts. Most intense gusts could be greater than 80mph - Long track supercells are possible over far southern central IN. Within these supercells, significant tornadoes are possible. Discussion: There is a growing concern for a localized severe weather outbreak over central Indiana late this afternoon and evening. Satellite and radar imagery depict numerous elevated thunderstorms with widespread rain and anvil cirrus over KY currently, of which many of the near term models have struggled to materialize. This could create some uncertainty on overall storm track this evening as even with modest moisture advection it will take some time for this area to recover. The current expectation is for this to result in a CAPE gradient across the southern portions of Indiana, further solidifying the development of robust convection this afternoon and evening. Current observations show most of central Indiana already in the mid to upper 70s with dew points near 60. There will likely be some low level mixing this afternoon that will continue to drop dew points into the upper 50s, especially north of I-70 prior to convective initiation. However further south, greater SW moisture advection and some anvil cirrus should keep low level dew points elevated, with dew points in the mid 60s prior to convective initiation. This will result in quick destabilization with widespread CAPE values greater than 2500 J/kg south of I-70. As the pressure trough pushes eastward, modest lift will be sufficient enough for explosive initiation across IL, of which is expected to reach the Indiana border between 4:30 and 6:00 PM EDT. Further analysis of the low level thermodynamics shows very steep 0- 5km lapse rates, averaging around 8 C/km. The 5km layer winds will generally be around 50kts, increasing this evening to 70-80kts. Given the steep lapse rates, and dry mid level air, dense and volatile cold pools are likely to develop within organized storms. These cold pools will be capable of producing isolated wind gusts greater than 90 MPH, but numerous 60 MPH wind gusts are likely south of the I-70 corridor. This same set up also is favorable for significant hail, although this threat will slowly wane as the convection become more linear this evening. Greatest winds are likely to be south of the I-70 corridor where the LLJ axis is centered, but scattered severe wind gusts are still possible north of I-70. There is also a tornado threat with these storms this afternoon and evening primarily south of I-70. Given residual capping over southern IN from the previously mention thunderstorms over KY this morning, along with a more favorable shear vector, some discrete convection is possible in the beginning of the severe thunderstorm threat (5-8PM). Modeled soundings currently show 0-3km SRH greater that 300 m2/s2 in this same region, of which is plenty sufficient for mesocyclone development and therefore supercells. Although LCLs are likely to be slightly elevated initially, very steep near surface lapse rates along with 0-1km SRH of 100-200 m2/s2 should be enough to overcome as the mesocyclones strengthen and become more mature. 7PM onwards the LLJ is also likely to increase further intensifying the low level shear. The main uncertainty with long track supercells will be how quickly organized convection grows upscale and becomes linear. Outside of supercell tornadoes, there is a QLCS tornado threat as these storms develop strong cold pools. If a tornado does happen north of I-70, this will likely be the storm mode. Given the aforementioned likelihood of robust cold pools and RIJ, there will likely be surges within any linear feature. These surges in the presence of strong LL shear this evening will likely be sufficient for a few embedded tornadoes within lines. && .LONG TERM (Saturday through Thursday)... Issued at 307 AM EDT Fri May 16 2025 An exiting low will move off to the NE at the start of the period. Behind the low, broad riding across the central plains will initially dominate this weekend. Pressure gradients between the system will keep wind gusts to around 25-30 mph during the afternoon on Saturday but will be much calmer for Sunday. A more active pattern is then expected for much of the work week as an upper low, with a couple of short wave, moves through the region. Models are struggling to determine the details at this time as different solutions show varying tracks and strengths to the system. Confidence on temperatures is also low as it will depend on what side of the low central Indiana ends up with. Despite the uncertainties, it does look like there will be a good amount of moisture to work with, so could see a threat for multiple days of heavy rain, and temperatures probably below normal for much of the week. Towards the end of the long term and into the holiday weekend, a ridging pattern may set up to bring from the rain expected next week, but it is still too soon to have much confidence in this yet. && .AVIATION (00Z TAF Issuance)... Issued at 631 PM EDT Fri May 16 2025 Impacts: - Severe thunderstorms expected through mid evening - Gusty winds through the evening then again on Saturday afternoon Discussion: A cluster of intense convection was tracking through western Indiana and will impact the terminals over the next few hours. KBMG and KIND are at greatest risk of strong wind gusts in excess of 40kts after 00Z for an hour or two along with brief visibility restrictions. Storms will be east of the terminals by 02-03Z with skies clearing. Expect southwest winds to remain gusty through the rest of the evening then will fall back to 10-15kts overnight as they veer to a more westerly direction. Broken mid level clouds will fill back in Saturday morning as the cold pool aloft expands across the area. Westerly winds will pick up again with gusts around 25kts during the afternoon. && .IND WATCHES/WARNINGS/ADVISORIES...None. && $$ MESOSCALE...Crosbie SHORT TERM...Updike LONG TERM...Updike AVIATION...Ryan ####018009256#### FXUS63 KJKL 162232 AFDJKL AREA FORECAST DISCUSSION National Weather Service Jackson KY 632 PM EDT Fri May 16 2025 .KEY MESSAGES... - There is an enhanced to moderate risk of organized severe thunderstorms with significant severe weather possible this evening into tonight. - After a break in rain chances on Saturday and Saturday night, shower/storm chances return at times through the middle of next week, especially during the afternoon and evening hours. - Temperatures will be nearer to normal from Saturday through Tuesday, then are forecast to be below normal for Wednesday to Friday. && .SHORT TERM...(This evening through Saturday night) Issued at 550 PM EDT FRI MAY 16 2025 Following the initial morning to early afternoon convection, a couple of storms/attempts at redevelopment that have moved across parts of southcentral KY have produced lightning and have not been as robust. Recently MLCAPE is analyzed at 1000 to 1500 J/kg in the northeastern and eastern counties where clouds and heating following earlier activity began the latest. Meanwhile, MLCAPE is analyzed in the 2000 to 2500 J/kg range while MUCAPE ranges from 1000 J/kg east to 2500 to 3000 J/kg in Wayne County where heating has been the most substantial and dewpoints are the highest. Shear remains substantial generally in the 55 to 65KT range for effective shear. Additional activity has developed upstream and should evolve into the anticipated linear convection/QLCS later this evening into the overnight. Currently there is a lull in the activity other than the storm in the western portion of the area. As the line approaches, an increase in activity ahead of it seems probable over the next couple or hours. RAP/SPC Mesoanalysis has the MLCAPE climbing to roughly 2000 to 2500 J/kg with MUCAPE possibly increasing toward 3000 J/kg ahead of the linear convection over the next couple of hours with effective shear in the 50 to 70KT range. Mid level lapse rates are progged to increase as the evening progresses to 7 C/km or more over the next with low level lapse rates not as steep. However, the main line should be well organized with a strengthen cold pool while the steepening mid level lapse rates indicate an increase in large hail potential in addition to a wind threat. Any discrete cells that form ahead of linear convection will pose a risk of all hazards, especially if they move along any boundaries or differential heating boundaries in which case the tornado potential would increase. Otherwise, with the anticipated QLCS convection, a threat of wind gusts possibly to significant levels (74+ mph) along with large hail and spin up tornadoes are possible. The line should arrive over the next 3 to 5 hours from the west with the convective complex crossing eastern KY into the first half of the overnight hours. The SPC Moderate risk in place for more western locations and enhanced risk for the remainder of eastern KY remains valid given the expected increasing parameter space and CAM and upstream trends. Additional Watches are probable as the evening progresses. In addition to the severe thunderstorm threat, if additional lead cells move over locations that were hit with heavy rain earlier in the day (between I-64 and the Cumberland Pkwy to Hal Rogers Pkwy and KY 80 corridors into Pike County). Also if additional lead cells produce heavy rain and are immediately followed by the QLCS/MCS/linear convective rain high water or flash flooding would also be possible. The axis of upper level ridging and height rises follow from Saturday and into Saturday night as the actual cold front moves through, with drier air filtering into the area. This will result in much quieter weather for Saturday and Saturday night. A decreasing gradient following rain from earlier today and tonight should set the stage for valley fog on Saturday night, especially for valley locations near and south of the Mountain Parkway. .LONG TERM...(Sunday through Friday) Issued at 500 PM EDT FRI MAY 16 2025 The period is expected to begin with the axis of upper level troughing from eastern Canada into the Northeast to near the eastern seaboard and the axis of upper level ridging from the Gulf into portions of the Central Conus/Plains to MT and into Saskatchewan. A shortwave trough or two is expected to be moving from the mid MS and Lower OH to TN Valley areas toward the Southeast/Southern Appalachians. Meanwhile at the same time, the axis of an upper level trough is expected to extend from BC into the Great Basin to Southwestern Conus. At the surface, the boundary that will have crossed the area during the short term period will have stalled from the Carolinas to the TN Valley to Ozark vicinity to southeastern CO/OK panhandle vicinity to low pressure ahead of the trough moving through parts of the western Conus. Along the western part of that boundary a sfc low should be developing in the lee of the Rockies as the period beings. Locally, the southern end of a ridge of high pressure over Canada and into eastern KY. Sunday, the initial shortwave trough should pass through the TN Valley and parts of the OH Valley to the Southern Appalachians and dampen and likely interact with the stalled boundary to the south of eastern KY. Some showers or storms could affect more southern locations in closer proximity of this boundary as the shortwave passes. Otherwise, some height rises occur behind this shortwave with the axis of upper ridging working towards the OH Valley and then shifting east of eastern KY by Monday night. However, a couple of shortwaves could cross the OH Valley and eastern KY from later Sunday into Monday night and by the time ridge axis shifts east, organizing low pressure tracking through the Central Conus should send the boundary initially stalled south of eastern KY into the region. Despite ridging possibly leading to times of capping or some suppression of the coverage of convection, the passing shortwaves and then the warm front approaching will lead to chances for showers and thunderstorms at times as early as later Sunday night and into Monday night. These chances could peak diurnally on Monday and as the warm front potentially nears late Monday night. With the ridge axis having moved east troughing initially over the western Conus that will have moved into the Plains and then the Central Conus should approach the MS Valley and eastern Conus by midweek. Some height falls should occur by late Monday night or Tuesday and continue into midweek. This will be preceded by sfc low pressure tracking from the Central Conus to the OH Valley through Tuesday night and Wednesday and then to the eastern seaboard through Thursday night and then off the east coast Friday. Uncertainty remains with the timing of the upper level troughing into and across the eastern Conus from midweek into the second half of next week and details and evolution of that trough. Following the warm front lifting across the area by midweek, a cold front should cross the area at midweek as well. Some strong storms cannot be ruled out as the low pressure system tracks across the OH Valley and eastern KY by later Tuesday into Wednesday, especially if any destabilization can occur ahead of the mid week cold front. Following recent rainfall, if additional heavy rain were to occur during the first half to middle of next week, that could become the bigger concern as highlighted by most recent WPC Day 4 and Day 5 EROs. && .AVIATION...(For the 18Z TAFS through 18Z Saturday afternoon) ISSUED AT 230 PM EDT FRI MAY 16 2025 The back edge of stronger convection was nearing the TAF sites as of issuance time. Initially, convection with reductions to MVFR or lower is most probable at KJKL and KSJS and an hour two or so of tempo groups for thunder on station were included there. For locations near KJKL and KLOZ some redevelopment could occur in the area after a couple hours of heating following earlier activity and PROB30 groups were included for thunder on station with MVFR reductions. Outside of thunder VFR is anticipated during the first 6 hours of the period. A round of more widespread liner thunderstorms with some potential cells in advance is expected during the 00Z to 08Z timeframe, likely arriving and crossing most of the TAF sites between 02Z and 06Z. A tempo group was included for most sites with wind gusts up to 35KT through severe gusts briefly could occur with the anticipated line of storms. MVFR or IFR reductions if not lower are expected at least briefly as this line passes. Outside of storms, winds should average south to southwest at 5 to 15KT with some gusts as high as 20 to 25KT. && .JKL WATCHES/WARNINGS/ADVISORIES... Flood Watch until 4 AM EDT Saturday for KYZ058>060-068-069-079- 080-083>088-104-106>120. && $$ SHORT TERM...JP LONG TERM...JP AVIATION...JP