Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/30/19

Area Forecast Discussion
National Weather Service La Crosse WI
620 PM CDT Wed May 29 2019 .SHORT TERM...(Tonight through Thursday Night) Issued at 252 PM CDT Wed May 29 2019 At 2 PM, a 700-600 mb frontogenetic band continues to produce a band of showers north of Interstate 94 this afternoon. The meso models show that this band will slowly weaken late this afternoon. Due to this, went with deceasing rain chances through the remainder of the afternoon. For tonight and Thursday, an opening closed low/trough, currently located over west-central Iowa, will move east across Iowa and northern Illinois. As this occurs, the 850-700 mb frontogenesis will increase. With ML CAPES of 1000-1500 J/kg, expect a band of showers and scattered thunderstorms to develop this evening and then continue into Thursday morning. With 0-3 km shear less than 35 knots, not anticipating any severe weather. Rainfall amounts will be up to a half inch. Waning of the showers is expected in the afternoon as the trough drops southeast of the area. Meanwhile, increasing northwest flow aloft will usher in a weak embedded trough and a chance of showers/isolated storms into the area late Thursday afternoon into Thursday evening. Otherwise, plan on highs Thursday in the mid/upper 70s amd lows Thursday night in the 50s. .LONG TERM...(Friday through Wednesday) Issued at 252 PM CDT Wed May 29 2019 Northwest flow aloft continues Friday into the weekend. A low drops southeast in the flow Friday with models in excellent agreement on the track mainly northeast of I-94. This will put us in the warm sector with southwest flow/downsloped air from the Plains moving in. NAM showing 925mb temperatures warming to near 25C. This is expected to push highs well into the 80s. Meanwhile there will be some increasing elevated/2-7km MUCAPE into the 1000-2000J/kg range as a cold front pushes in from the northeast later in the afternoon/ Friday night. Bufkit showing this elevated instability as well with an inverted-v look to it. Shear will be weak though, generally in the 15-20kt range. So, thinking sub-severe storms at this point if any do form with possibly some gusty wind and small hail. Cooler air filters in behind the cold front Saturday with highs topping off in the upper 60s to the middle 70s. Could also see some lingering shower/isolated thunderstorm chances mainly in the morning as that frontal boundary slides south through the remainder of the area. High pressure builds in Sunday for some much-needed drier weather. Look for pleasant temperatures in the upper 60s to lower 70s. Shower and thunderstorm chances return to the area Monday afternoon and linger through Wednesday as low pressure slowly makes its way across the Northern plains into our region. Temperatures meanwhile look to be right around seasonal norms with highs in the upper 60s to upper 70s. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 620 PM CDT Wed May 29 2019 Cigs: tricky forecast with most models nudging low level saturation (and MVFR cigs) right up the TAF sites tonight. Latest RAP more aggressive with northward movement and suggest several hours of MVFR. For the moment, will hold with current forecast (VFR). Will monitor and update if northward trends win out. After low pressure exits east early Thu morning, mostly sct-bkn high level clouds for Thu. WX/vsby: inverted trough/elevated frontogenetic region north of low passing west-east south of the local area tonight will fire up shra/ts tonight. HRRR/RAP keep this activity south of I-90. Winds: mostly light/vrb tonight, becoming northwest Thu morning will passage of low. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Boyne/DAS LONG TERM...DAS AVIATION...Rieck
Area Forecast Discussion
National Weather Service Hastings NE
613 PM CDT Wed May 29 2019 .SHORT TERM...(This evening through Thursday) Issued at 319 PM CDT Wed May 29 2019 Aloft: RAP tropopause analyses and WV imagery shows a complex split flow over the CONUS. A high was over the Canadian Prairies with a trof underneath over the Wrn USA. The low that mvd into NEB yesterday was near FSD with a trof extending SW acrs NEB. Spaghetti plots show the low will inch S to OMA by 12Z/Thu and then weaken as it heads SE to MO/IL tomorrow. The trailing trof will then sink to the NEB/KS border by 00Z/Fri. Meanwhile...the high over Canada will mv SE into the Nrn Plns. Surface: Low pres was over IA and mvg away from the rgn. Weak 1016 mb High pres was over WY. This high will gradually slide SE and be over Wrn KS/OK/TX tomorrow. Rest of this aftn: P-M/cldy. There might be a few very low-top shwrs form. High temps will be around 5 the 60s. About 10F below normal. Tonight: P-M/cldy. A few light shwrs will be psbl as the trof mvs in. Gvn disagreement in timing/location in the simulated mdl reflectivity...did not get fancy with POPs. Lows around 50F. Thu: M/sunny to p/cldy at times. Still could see a few light shwrs with the upr trof. Warmer with near normal highs in the upr 70s. .LONG TERM...(Thursday night through Wednesday) Issued at 319 PM CDT Wed May 29 2019 Aloft/Pattern: The persistent/blocked Wrn trof/Ern ridge over the last 10 days will finally breakdown. By mid next wk...a pattern more typical of summer is fcst to evolve with the primary band of Westerlies along the US-Can border. Spaghetti plots of the last 2 runs of the UKMET/EC/GFS/GFS-FV3/CMC are tightly-clustered on this scenario...allowing good confidence. That means overall warmer and drier wx here. There are svrl shrtwv trofs embedded within the Wrn longwave trof. One is currently along the Srn CA coast will mv inland... round the base of the Wrn trof and cross NEB/KS Fri AM. This trof will be of little consequence. Another vort max currently near the intersection of UT/WY/CO is fcst to become mobile and cross SD Fri night. That trof should be of little consequence as well. A clsd low will form over OR today...drop into Srn CA Fri and become cut-off. This will induce downstream height rises. A ridge will build over the Rckys Fri and it will gradually mv over the Plns Sun-Mon. The Nrn extent of that ridge will get flatten as Mon night thru Wed...probably as a wk shrtwv trof mvs E thru the Nrn Plns. But there is mdl disagreement on location/timing. Surface: Very wk high pres will remain over the Cntrl/Srn Plns Fri ...but a Canadian cool front will slip into the Nrn Plns. This front will cont S and cross the CWA Sat. Wk high pres will arrive Sat night but depart to the E Sun as a warm front forms from Wrn ND thru cntrl KS. As strong low pres mvs thru Srn Canada...this warm front will move E thru the CWA Mon night. A sfc trof in the warm sector is fcst to mv thru Tue aftn. Wk high pres should then arrive Wed. Some of these details are a bit sketchy gvn the uncertainty noted aloft. Temps: near normal. Tue is looking like the warmest day of this fcst and temps could be abv normal. It could get pretty humid Mon-Tue as dwpts climb into the mid-upr 60s. Rain: Drier than normal...but there will be an isolated tstm or two here and there from time to time. The overall the chance of rain will be low except Sun ngt into Mon...when the chance of tstms will increase on the cool side of the warm front. Instability and shear will be sufficient for storms to be svr. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 608 PM CDT Wed May 29 2019 VFR conditions are forecast trough the period as NW winds and drier air moves into the area. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Kelley LONG TERM...Kelley AVIATION...Beda
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1038 PM CDT Wed May 29 2019 .UPDATE... A broken line of showers and storms continues to move eastward across Texas and towards our area. We do have some amount of instability available to these storms, but we also find ourselves underneath a 700 mb thermal ridge, and divorced from more significant upper troughing. If the line`s cold pool can sustain low level convergence, we can continue to manage a broken line of showers and storms, but capping and upper subsidence indicated in Austin AMDAR soundings, as well as a decreasing moisture gradient to the east per GOES-East, will not be favorable for line maintenance. All in all, continue to keep decent PoPs in place in our far northwestern edge, but in keeping with a scenario similar to the HRRR and other CAM guidance, kill things off pretty rapidly from there. Nearer the coast, do increase PoPs as onshore flow should result in the development of streamer showers towards dawn. Later tomorrow, bring PoPs up from both ends, as the upper jet`s right entrance region comes closer, along with better potential for forced lift as the cold front shows up on the scene. && .PREV DISCUSSION /Issued 620 PM CDT Wed May 29 2019/... .SHORT TERM [Tonight Through Friday Night]... Low pressure was located near the Big Bend region and high pressure was over the FL panhandle at mid-afternoon. The flow between these two features has allowed a ribbon of deeper moisture to develop over the western third of the CWA on a strong onshore flow. Isolated showers will persist near this corridor of deeper moisture this evening, however most of SE TX will likely remain dry through 9 PM or so. A cold front over N TX will slide south later tonight. This feature will bring scattered showers and thunderstorms to the area late tonight. PW values will increase to between 1.80 and 2.00 inches but instability is not terribly impressive with the best dynamics confined to mainly the northern third of SE TX. SPC has outlooked the northern third of the region, roughly north of a Brenham to Huntsville to Trinity line. If severe weather does develop, the primary severe weather hazard will be large hail and damaging winds. On Thursday, the weak cold front will approach I-10 and probably stall. Low level convergence along the boundary coupled with weak lift provided by a weak right rear quad of a departing 75 kt jet should allow scattered showers and storms to develop. Best rain chances look to occur between 15-21z as PW values increase to around 1.90 inches and mid level frontogenesis peaks. Cloud cover and precip should suppress temperatures a bit and will shave a few degrees from todays high temps for Thursday. Overnight low temperatures will remain warmer than normal with cloud cover. Upper level ridging over the western Gulf expands toward the Upper Texas Coast on Friday. A weak upper level disturbance sliding over the top of the ridge should generate scattered showers and thunderstorms. Not sure if increasing subsidence from the ridge or lift from the short wave will prevail so will go with 30/40 PoPs for now. 500 hts build as the upper ridge expands and temperatures will begin to warm back up. Lower 90`s will prevail over the southern 2/3rds of the CWA with cooler temperatures to the north closer to the track of the short wave. 43 .LONG TERM [Saturday Through Wednesday]... Upper ridging will commence a dry period that will dominant the extended. Southern based mid to upper level ridging with no upper level support will provide the subsidence required to keep any precipitation confined to the mesoscale...either early day near coastal streamer showers or isolated showers along the sea/bay breeze boundaries. Slight rain chances across the far northern counties may exist on both Friday and Saturday afternoons to account for weak shortwave disturbances passing atop the ridge axis in the ArkLaTex region. Mostly cloudy mornings will evolve into partially cloudy afternoons...average middle 70 minimum temperatures with afternoons warming into the lower to middle 90s. Overall moisture will ebb and flow to as low as 1.2 inches to near 1.7 inches pwats under southern steering flow. Afternoon dew points in the lower 70s with ambient lower to middle 90s will produce near 100 F heat indices. 31 .AVIATION [00Z TAF Issuance]... Extremely complex forecast ahead for the area. Here is a brief sketch of what may lie ahead - I expect that tweaks, potentially even wholesale changes may be needed in future issuances. Overnight: a line of strong to severe storms will weaken as it slowly drops towards Southeast Texas. Sketch out a period of VCTS at CLL and UTS overnight as to when storms - if any - are expected to arrive. Very conditional threat here, and there may be no storms at all. Tomorrow: a cold front drops into the area. Separated from the best forcing, there is not a lot of confidence in timing or strength. General idea tonight is that the front will push through the northern third to half of the area fairly well this morning, then slow as it nears IAH. It should stall out, and I end the forecast period with things in the general vicinity of the Houston terminals. Use PROB30s for now to highlight most likely windows at this time. LBX and GLS: Despite the complexity elsewhere, these TAFs are fairly straightforward as I stall out the front before reaching here. If the front pushes more towards the coast, more than a simple VCTS window may be needed. .MARINE... Surface high pressure building down for the Southern Plains through late week will weaken the onshore pressure gradient. Thus, winds will be on the decline through Friday and seas will accordingly fall an average 3 to 4 feet by Saturday. Late week minor coastal wave run up to between 2 to 2.5 feet MLLW and weakened rip currents. Overall high pressure across the local waters from the weekend on through mid next week will generally maintain near 10 knot onshore winds and sub 2 foot significant wave heights. 31 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 74 87 72 87 71 / 50 30 30 40 20 Houston (IAH) 76 89 74 90 74 / 20 60 40 40 20 Galveston (GLS) 79 85 79 87 79 / 30 30 10 20 10 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM. Small Craft Advisory until 11 PM CDT this evening for the following zones: Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for the following zones: Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$ UPDATE...Luchs/Overpeck SHORT TERM...43 LONG TERM...31 AVIATION...Luchs MARINE...31
Area Forecast Discussion
National Weather Service North Platte NE
634 PM CDT Wed May 29 2019 .SHORT TERM...(This evening through Thursday night) Issued at 321 PM CDT Wed May 29 2019 The upper low which has produced rain across the region for a few days now is swirling slowly across SD, MN and IA. The model consensus backed by the RAP and HRRR show lopes of energy dropping south and setting off showers across ncntl Nebraska tonight. Most of this additional rain will occur east of highway 83. The forecast Thursday and Thursday night is dry. Sfc high pressure will build south through the cntl Rockies and this places wrn and ncntl Nebraska in a stable northwest flow. None of the models show afternoon destabilization, despite cold air aloft. The temperature forecast follows the guidance blend plus bias correction. This produced lows in the 40s to around 50 tonight, highs in the 70s to near 80 Thursday, and lows in the upper 40s to mid 50s Thursday night. We are expecting nearly full sun Thursday with afternoon cumulus clouds. The temperature forecast might be optimistic. Bias correction cooled the guidance blend down a degree or two. .LONG TERM...(Friday through Wednesday) Issued at 321 PM CDT Wed May 29 2019 The next best chance of rain occurs Sunday afternoon and evening. The GFS and ECM are in fairly good agreement sending a ridge-runner type wave across the Black Hills or the Laramie range. The activity appears to grow upscale as it moves east into deeper moisture across wrn Nebraska. POPs are fixed at 50 percent for this event and winds aloft are around 30-35kts which suggests some potential for strong or severe development. The days 4-8 severe weather outlook from SPC suggests it is too early to predict the potential for severe weather. Otherwise the forecast features some low chance POPs with a wave dropping through the nrn Plains Monday and Tuesday. The temperature forecast follows the model blend for highs in the 70s to mid 80s. There may be opportunities to mark these highs "up" as temperatures at the h700mb level warm to around 12C by Tuesday. The progression of warming is gradual so temperatures should rise a few degrees each day, ultimately producing highs in the upper 80s around 90 Monday and Tuesday as suggested by the bias corrected GFS and MEX guidance. The uncertainty in the temperature forecast revolves around back door cold fronts, cloud cover and moisture return which can all have a negative impact on predicted highs. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 624 PM CDT Wed May 29 2019 VFR conditions should prevail over the next 24hours with the lowest ceiling heights this evening and continuing to improve overnight into Thursday morning. && .HYDROLOGY... Issued at 321 PM CDT Wed May 29 2019 It is the opinion of local officials and long time residents of the Sandhills that the water table associated with Ogallala aquifer has risen sufficiently to cause significant overland flooding in many areas. For example, State highway 97 north of Mullen was reported to have 18 inches of standing water over it Wednesday. The result of overflow from one of the many lakes across this region. No significant rain is expected until Sunday and this should allow for improvement. It is uncertain how long it will take for these flood waters to recede completely. Minor flooding is expected on the North Platte river above McConaughy and near bankfull conditions are expected below it. Minor flooding is underway along the Elkhorn river above Ewing and near bankfull conditions are occurring on the Calamus river below Virginia Smith Dam. The Calamus reservoir is near capacity. The Elkhorn river should remain high for several days but the Calamus and North Platte river below McConaughy should gradually recede. The North Platte river above McConaughy is expected to remain high for several days. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Gomez HYDROLOGY...CDC
Area Forecast Discussion
National Weather Service Louisville KY
917 PM EDT Wed May 29 2019 .Forecast Update... Issued at 916 PM EDT Wed May 29 2019 Convection continues over mainly far southwestern KY this evening. Convection over much of the WFO LMK area has subsided this evening with the loss of heating and a relative area of higher stability over much of the region. Convection has shown a downturn in strength over the last hour as cold pools are now emanating eastward from under the convection. The downward trend in strength should continue over the next few hours as this western KY convection moves eastward into a more stable airmass. For the overnight period, convection over western KY is forecast to move northeastward and back into the WFO LMK area overnight. We`ll see rainfall move back into our western counties within the hour and we may see some showers back in the Louisville metro region by 1100 PM tonight. While surface based instability will continue to wane, model proximity soundings do show some elevated instability over the region. Thus, it will not be surprising to see some thunder with this activity later on tonight. Best chances for rainfall overnight look to be west of a line from Bowling Green to about Frankfort or so. Thus, have kept higher PoPs in these areas, with a lesser chance further east and southeast. As cold front out to the west pushes eastward tonight, convection will likely spread further eastward into the Bluegrass region after dawn on Thursday. Overall threat for severe weather tonight looks rather marginal. Forecast shear profiles are expected to drop off while the low-level jet refocuses out to the west. Marginal instability will be present, so some storms could pose a gusty wind hazard, though the most likely hazardous threat would be heavy rainfall and isolated flooding issues. Will highlight these threats in the updated Hazardous Weather Outlook product. Have done a quick refresh of the grids and text/graphical products are in production and will be available shortly. Issued at 700 PM EDT Wed May 29 2019 Convective outflow boundary from morning convection had some severe cells that developed along it. One HP supercell formed over Christian and Muhlenberg counties and slid down the boundary producing large hail through southern Butler, northern Logan and into Warren county. While these storms have diminished, renewed convective development along old reinforced outflow boundary has developed. This activity is expected to lift northward. Short range high resolution models suggest that it will hold together through around sunset and then may diminish. The highest chances of precipitation this evening would be in areas west of the Natcher Parkway (or the western third of our forecast area). Will continue to monitor the data and environment this evening and make future adjustments to the overnight forecast in a few hours. && .Short Term...(This evening through Thursday) Issued at 319 PM EDT Wed May 29 2019 ...Severe Threat Remains For Southern KY This Afternoon... Convection from the first wave was never really able to get established ahead of the outflow boundary, and has now pushed east of the area. Focus is now on the still untapped airmass along and south of the outflow boundary which is now across our southern KY counties. Of particular interest is an isolated supercell that has latched onto the boundary and will be moving into northern Logan county soon. Large hail, downburst winds, and perhaps a tornado threat will exist given the localized enhancement to low level SRH offered by the boundary. Right now the overall setup is only offering around 100 M2/S2 of effective SRH in that area, which isn`t very favorable for tornadoes by itself. Keeping a close eye on this storm as it approaches northern Logan County. Otherwise, the other area of concern is southern IL/SW Indiana where strong instability has developed in the wake of morning convection. Some decent moisture convergence is going on in that area right now, and if convection pops we will likely have to watch for strong to severe storms developing in that area and moving back into our southern IN counties this evening. Not overly confident in this scenario but will have to monitor. So, the actual forecast will call for isolated to widely scattered storms for the remainder of the afternoon and evening, most likely down along southern KY where the airmass remains untapped. There should be a relative lull around and briefly after Midnight before the next round of showers and storms begins to move into our SW ahead of a disturbance moving into the lower Ohio and Wabash River Valleys. Some of the storms could become strong early Thursday and through the day however overall instability will be a little in question despite a pretty decent shear profile. Cold front moves through the area late evening, briefly ending shower and storm chances from W to E. Lows tonight drop to the upper 60s, and highs tomorrow reach the upper 70s and low 80s. .Long Term...(Thursday night through Wednesday) Issued at 257 PM EDT Wed May 29 2019 Thursday Evening - Sunday... Lingering showers and a few storms are possible Thursday night into Friday morning behind the cold front as the upper low moves into the region. Isolated convection will then be possible Friday afternoon mainly in east central KY as an upper level disturbance moves off to the southeast. Otherwise, expect mainly dry weather Friday afternoon through early Saturday as ridging builds in over the central U.S. This will keep us in northwest flow behind the upper low, bringing cooler temperatures to the area. High temperatures Friday will be in the upper 70s to low 80s. The next round of showers/storms are possible as early as Saturday afternoon if a leading shortwave can spark convection. If not, showers/storms may hold off until Sat night into Sunday as a cold front dives south through the Ohio Valley. Sunday Night - Wednesday... A Canadian High will then build over the Great Lakes and slide to our northeast at the beginning of next week, keeping us mostly dry. We return to southwest surface flow Tuesday, bringing high temperatures back into the low-mid 80s Tuesday and Wednesday. && .Aviation...(00Z TAF Issuance) Updated at 700 PM EDT Wed May 29 2019 Convectively induced outflow boundary resides across southwestern KY this evening. This line is roughly from KHOP westward through KPAH. This boundary is forecast to lift northward this evening and will primarily affect western KY. The last few runs of the HRRR model do lift this boundary northward this evening, but the convection in the model weakens after sunset. Overall confidence in this is rather low, so will keep some VCTS in KHNB/KSDF per the previous amendments. KLEX looks to be least affected by convection this evening. Probably will keep a few hours of VCTS in at KBWG due to its close proximity to remnant outflow boundary. Overnight, we may start off dry, but another wave/disturbance will move into the region late tonight and into the pre-dawn hours of Thursday. Overall, it appears that KHNB/KSDF/KBWG would be most affected with this activity with KLEX being least affected due to its eastward location away from convection though KLEX will likely see additional showers Thursday morning as the disturbance rolls northeastward. Winds overnight will be out of the southwest at 5- 10kts and will pick up again during the day on Thursday. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update.......MJ Short Term...BJS Long Term....AMS/JMB Aviation.....MJ
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
815 PM CDT Wed May 29 2019 .UPDATE... 814 PM CDT The going forecast message of increasing shower and thunderstorm chances later this evening into the overnight looks good, along with some chance of strong to possibly a few severe storms. Confidence is low though on just how far north any stronger storms may reach into our area, as well as the duration of the highest storm coverage, as it may only be a few hour window. All in all, the risk of hazardous weather is consistent with that of a Marginal to low end Slight Risk for both severe and flooding. Anomalously strong southwest flow aloft of 120 kt at 250 mb is set to spread over the forecast area in the next few hours per satellite water vapor imagery and 00Z upper air observations. Embedded within this are a couple short waves, one approaching the Quad Cities area and then a second stronger one over central/southern Missouri. Broad ascent from the jet streak and waves will encompass the area by shortly after midnight. The ILX 00Z sounding indicates over 2500 J/kg of MUCAPE, which matches the SPC RAP mesoanalysis that also analyzes around 1000 J/kg over the southern CWA. This instability aloft should inch upward these next several hours. These are the ingredients in place for the uptick of storm coverage into the CWA by early overnight. A couple caveats are that the low-level jet strength is only of 25 kt into the southern CWA, and a fairly solid area of ongoing convection along the surface warm/stationary front in central Illinois might limit widespread moisture transport into the area. This would have impacts on how widespread of thunderstorm coverage and any flash flood threat. Nonetheless, showers with embedded thunder are likely in most places overnight, and an isolated to scattered severe threat exists with deep layer shear forecast to peak around 45 kt. The main threat would be hail along with possibly some strong winds. The recent tornado warnings near Iowa City and Cedar Rapids west of the area are closer to the surface low where there is some stronger near-surface flow and where there was some late day destabilization at the surface. So we are not anticipating that threat here, though could have some supercell structures with a few storms given the sufficient 0-3 km shear and helicity. MTF && .SHORT TERM... 241 PM CDT Through Thursday night... Thunderstorms will continue to be the focus of the forecast through the near term. The persistent upper trough over the western U.S. is breaking down a bit with an upper ridge remaining over the southeast U.S. Water vapor imagery shows a shortwave trough moving northeast across Oklahoma this afternoon and this will be the focus for thunderstorm development to our southwest over the next few hours and then locally this evening. At the surface, the pattern is rather ill-defined with a weak east-west ridge to the north and a surface low over western Iowa. A warm front is positioned south of the CWA. Moderate instability has developed over southwest IL and is gradually expanding northward up against the front. Satellite suggest that the front, which may have blended with old outflow from overnight convection, is still moving southward based on progression/development of lower level clouds. It seems that the instability analysis may be a little too aggressive with the current northward extent. This, along with the fact that there is little in the way of a triggering mechanism, supports minimal potential for any type of convection to develop in the CWA through late afternoon or early evening. Getting back to the upper wave coming across Oklahoma, current convection moving northeast across SW MO and points southwest is expected to expand or new development may occur to its north as the trough moves along and is aided by a cold frontal boundary extending south from the low over Iowa. Guidance is not in great agreement in how things play out but based on observed trends and forecast of larger scale features, expect that thunderstorms will move in from the southwest by mid evening and continue across the area into the early overnight. Severe potential is a bit of a question mark given how far south instability currently is, though it will likely start to lift north into the evening. Still favor areas south of I-80 or perhaps even U.S. 24 for large hail and gusty wind threat, with little threat to the north. As far as heavy rain potential, guidance is mixed but based on current trends and guidance that seems to possibly have a better handle on the larger scale, the best moisture largely peels to the south of the area into early tonight. That said, isolated heavier rainfall is still possible, where convection is most intense and persistent. Most if not all activity should be exiting to the east Thursday morning. Another upper trough crosses the area during the afternoon evening but has much less moisture to work with than recent systems. However, it still supports low chances for showers and isolated thunderstorms. Highs will be in the low to mid 70s for most areas but lakefront areas will be kept cooler. May be a little optimistic with lower 60s at the lakefront. Shower chances may linger in the south into early evening but should exit for the overnight. MDB && .LONG TERM... 206 PM CDT Friday through Wednesday... Main forecast concerns through this period include showers and storms with a cold front and upper level short wave on Saturday... followed by another round of rain and storms Tuesday into Wednesday with another upper level shortwave. Perhaps equally noteworthy is the stretch of dry weather expected Sunday and Monday! This assumes a vigorous upper level shortwave currently progged to pass to our northeast stays there. The upper flow pattern over the local area transitions to a northwest flow with the exit of Thursday night`s upper level trough. Models coming into better agreement on the details in bringing an upper level shortwave across the northern plains and into our area Saturday. Dynamics impressive enough to support thunderstorms... and we`ll need to monitor parameters as the event draws nearer in order to determine just how feisty those storms may become. Fairly sprawling surface high pressure builds into the area Sunday lasting into Monday. Temps will be a little below seasonal norms... especially near Lake Michigan where winds will have an onshore component both days. Split flow developing over the mountain west mid-week next week as the west coast upper low moves east complicates our forecast for that time period... however current model trends suggest perhaps a couple of different periods of rain Tuesday and Wednesday... warranting low pops in the forecast that period for now. Ed F && .AVIATION... For the 00Z TAFs... VFR conditions in place at the start of the period, with these conditions likely persisting for much of this evening. Expect precip chances to increase across all of the terminals close to around the midnight time frame tonight, with VFR ceilings spreading overhead during this time. Will see current showers and storms across central IL likely increase in coverage as they lift north through the evening hours. Do have confidence for at least a couple hour window of thunder tonight, with some possibility that this thunder lingers around slightly longer than currently forecast. Under these showers and storms, will see vis drop to around 3sm, with some 1-2sm vis possible in the stronger storms. Thunder chances will lower during the overnight hours, but with showers likely continuing into the early morning period on Thursday. Ceilings should stay mainly VFR, though a period of MVFR will be possible. VFR and mainly dry conditions expected on Thursday, as additional precip development Thursday afternoon should remain just south of the terminals. Easterly winds in place this evening expected to become more southerly tonight, and then southwest to west on Thursday. Rodriguez && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Marquette MI
731 PM EDT Wed May 29 2019 .SHORT TERM...(This evening through Thursday) Issued at 343 PM EDT WED MAY 29 2019 Temperatures today climbed well into the 70s, as the Lake Superior breeze came through temperatures were quickly knocked back down into the 60s inland to 50s near the lake. Tonight and early Thursday morning, a cold front will cross Lake Superior and Upper Michigan, which will switch the prevailing winds to more northerly. This will hinder high temperatures tomorrow for most of all Upper Michigan outside of Iron and Dickinson Counties which may sneak out a few 70s. Should the front come in slightly later than forecast, expect temperatures to climb further into the 70s. RAP analysis and model upper air maps show confluent flow at both 500 and 250mb which will contribute to NW flow, sunny skies, and dry conditions. The big question for Thursday, is just how far the RH values fall in the afternoon. Current forecast shows RH values fall into the 40s east, and perhaps into the 20s in western and central interior. NAM/GFS forecast soundings show mixing up to around 750- 800mb. This deeper mixing has the potential to create gusty conditions at times with winds blowing up to 20 kts at times inland. .LONG TERM...(Thursday night through Wednesday) Issued at 416 PM EDT WED MAY 29 2019 A weakly negative NAO pattern with a blocking ridge centered near the Davis Strait and associated trough over eastern Canada will favor northwest flow through the northern Great Lakes through the weekend. As a ridge over western gives way to lowering heights a more zonal pattern is expected to develop next week. Thursday night, with favorable radiational cooling conditions at least into the evening, the forecast maintains temps toward the lower end of guidance for inland locations. Readings into the lower 30s at favored cold spots could result in patchy/areas frost inland central and east. Some increase in clouds expected overnight with increasing mid-level moisture and weak forcing ahead of a shortwave and associated sfc low moving down from southern Canada may stop temps from falling or cause a slight rise in temps toward sunrise, especially over the west. Fri, a shortwave trough diving se through Ontario will drag a cold front into the region. WAA and moisture advection ahead of the front will bring MLCAPE values up into the 500-1000 J/Kg range for counties along the WI border by Friday afternoon. Although the stronger fgen/isentropic lift and higher pcpn chances remain north of Upper Michigan into the afternoon, as the front approaches, expect sct/isold t-storms will develop over the interior west and spread into south central Upper Michigan by evening. Deep layer 0- 6km shear to 50 knots suggest that there could be a conditional risk of a few strong/severe storms. Sat-Mon, high pressure is again expected build across the area and dominate with confluent nnw mid/upper flow. Models diverge by Sunday as the 06z/12z GFS and majority of GEFS ensembles maintain dry conditions under sfc high pressure and confluent flow aloft while the 00z/12z ECMWF advertises a fairly potent shortwave spreading showers and batch of cold air (850 mb temps lower near 0C) across the Upper Great Lakes. All models suggest drier conditions will prevail on Monday although the ECMWF indicates a much cooler day than either the GFS with cold air lingering over the area from in the wake of the stronger shrtwv on Sunday. Mon night into Wed, As the flow becomes more zonal across the northern CONUS, moisture/instability will move back toward the area along with increasing shower chances with the approach of a sfc trough from the Upper MS valley. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 731 PM EDT WED MAY 29 2019 Under a dry air mass, VFR conditions will prevail thru this fcst period at KIWD/KCMX/KSAW. NNE winds will become gusty to 15-20kt at KSAW Thu aftn. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 343 PM EDT WED MAY 29 2019 Lake Superior will remain below 20 knots through the weekend. There are some indications of winds near 25 to 30 knots mid next week, but confidence on for those winds are low. In the near term, expect a trough to pass late this week bringing showers across the lake on Friday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...JLB AVIATION...Rolfson MARINE...JAW
Area Forecast Discussion
National Weather Service Pueblo CO
341 PM MDT Wed May 29 2019 .SHORT TERM...(This evening through Thursday) Issued at 340 PM MDT Wed May 29 2019 Current water vapor imagery and upper air analysis is indicating generally weak west to southwest flow aloft across the region, as a weak upper trough continues to dig across the Rockies this afternoon. Cold air aloft (-18C to -20C at H5) has allowed for steep lapse rates and scattered to numerous showers, as well as a few thunderstorms, to develop across the higher terrain this afternoon, with showers spreading east across the high valleys and trying to move east across portions of the I-25 Corridor this afternoon. Snow levels have remained relatively high (around 10,000 feet) this afternoon, with CDOT cameras indicating snow falling across the higher mountain passes along with wet roadways, though the Pikes Peak cam is indicating some light accumulations at this time. Tonight and Thursday...Weak upper trough continues to dig across the Rockies tonight as parent upper low across the Northern High Plains continues to slowly lift north and east through the day tomorrow. The latest model runs continue to indicate weak upper level ridging building across the Central and Northern Rockies, as more Eastern Pacific energy digs across the West Coast. With that said, with loss of heating, will see showers and storms over the higher terrain diminishing through out the evening, with the biggest question being where the best coverage of showers moving across the I-25 Corridor will be, as the higher res HRRR runs have been waffling on better coverage across COS and northern portions and PUB and southern portions of the Corridor. At any rate, I kept scattered pops in through the evening, with slowly clearing skies across the region into early Thursday morning. For tomorrow, with warmer temperatures, some 5 to 15 degrees warmer than today, and residual moisture, should see another round of scattered afternoon showers and thunderstorms, with greatest coverage over and near the higher terrain. Good see a few stronger storms, with progged capes of 600- 1200 j/kg across the area, though with weak flow aloft and less shear, would be the pop and drop variety, expect for areas along the Raton Mesa, where models indicate the best shear supporting a rotating storm. .LONG TERM...(Thursday night through Wednesday) Issued at 340 PM MDT Wed May 29 2019 Thursday evening into Friday morning...Mixed layer CAPE values of around 1,000 to 1,200 J/kg along the southern CO border from the Raton Mesa to the eastern border with some marginal deep shear (approaching 30 kts) will continue to be possible during the evening hours, which could produce a strong to marginally severe storm or two. Elsewhere, any storms that do develop should be more of the garden variety type. Some light snow will also possible over the higher elevations, generally above 10,000 feet. Friday through Wednesday...An upper level trough is expected to set up over the western CONUS, which should bring some mid to upper level ridging over CO starting Friday afternoon. As a result, westerly flow aloft is expected Friday afternoon, becoming more southwesterly through the weekend and early parts of next week as the trough slowly digs southward into the far southwest CONUS. The trough and ridge are expected to then be relatively stationary through the first half of the week. This pattern will promote diurnal showers and thunderstorms each day, especially over the mountains and across the plains. Sunday appears to be another day with a potential for stronger storms to develop over the far eastern plains as stronger southerly winds at the surface should bring additional moisture to that area. Models are also indicating that CAPE values could approach 2,000 J/kg with moderate deep shear values (greater than 40 kts) during the afternoon and evening hours somewhere near the CO - KS border. The GFS has the higher CAPE and shear values located farther west into CO, while the ECMWF has them located in western KS. Models suggest that this trough will finally progress eastward by mid week, but it is too uncertain at this time to know exactly when or how quickly it will move. Temperatures should gradually warm through Monday to near 90 for the plains and mid 70s in the high valleys before moderating Tuesday and Wednesday. With the warmer temperatures and diurnal precipitation chances, the flood potential over the burn scars will likely need to be monitored during the weekend and early part of next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 340 PM MDT Wed May 29 2019 Mainly VFR cigs expected at COS and PUB through early tomorrow morning, with showers and thunderstorms over the higher terrain west of the terminals this afternoon and evening. A few showers look to move off the higher terrain and across the terminals late this afternoon and early evening, bringing the potential for brief MVFR cigs, especially at COS. Northerly winds 10-15kt through the day look to become light and variable overnight, and then become generally light upslope through mid morning Thursday. Another round of afternoon showers and storms can be expected tomorrow afternoon, with the best coverage over and near the higher terrain. VFR conditions expected at ALS through the period, with scattered showers and storms over the higher terrain this afternoon and evening, possibly moving across the terminal late in the afternoon or early evening. Breezy south to southwest winds 10-20kt through the afternoon, becoming light and variable overnight. Another round of afternoon showers and storms can be expected tomorrow afternoon, with the best coverage over and near the higher terrain. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...MW LONG TERM...CARLBERG AVIATION...MW
Area Forecast Discussion
National Weather Service Shreveport LA
732 PM CDT Wed May 29 2019 .UPDATE... To headline new Tornado Watch 296 until 06Z/1 a.m. & AVIATION && .SHORT TERM... The SPC has bridged the old Tornado watch 293 into more of AR and issued 296 keeping things covered for much of our area now through the evening hours. Thunderstorms are lining up from near Tyler to Mount Pleasant and nearing DeQueen. A lot of discrete smalls coming together now is hopefully good news along with the setting sun in an hour. /24/ && .AVIATION... For the ArkLaTex, afternoon convection has kept just out of range, but will overspread KTYR/KTXK soon. Beyond that, certainty depends on cool pool of rain cooled air to help what is a very weak cool front approaching. Southerly flow will keep TS active overnight with the SVR threat diminishing after sunset. Overnight activity will be tempoed for additional terminals upon approach of the SQ line. SW winds at daybreak will veer to W/NW into the afternoon as front eases over our area. Additional convection is possible, but will be much weaker by comparison. /24/ && .PREV DISCUSSION... /issued 410 PM CDT Wed May 29 2019/ SHORT TERM.../Tonight through Thursday night/ Cloudy and cooler in the NW with mid to upper 70s in rainy areas, but most of our area is in the mid to upper 80s with 90 at Natchitoches at 90 now the hot spot. The SE surface winds and S/SW aloft are presenting the tornado threat in our West with the cap barely holding over SHV. However, the models indicating a slow push into the heart of the area this evening and still with some QLCS potential, but even the HRRR is a little less bullish now compared to a couple of hours ago. The current tornado watch goes until 8 pm, so depending on evolution of convection we could not only wide down the tornado threat, but perhaps even the flooding threat for the overnight. Stay tuned. We added a couple of counties to the Tornado watch and pushed up the flash flood watch start time. A weak shift to NW will unfold mid to late morning helping to further the pops and weather across much of the cwa. Thursday will be cooler by comparison, but not less much muggy at least to start. Patchy fog may also become a problem for wet spots. Highs tomorrow will slowly warm as the low clouds early will be stubborn, but low to mid 80s may work out. Overnight lows will range in the 60s for early risers on Friday. /24/ LONG TERM.../Friday through Tuesday Night/ Expect slightly drier and cooler air to hang on through Friday and Friday night in the Four State Region, although an isolated shower or storm still cannot be ruled out in southern/southwestern zones near where the previous frontal boundary stalls and washes out. Thereafter, expect heat to build as an upper level ridge builds towards TX and westerly flow vectors aloft (over our region) institute a hotter regime. There is some opportunity for a marginal "northwest flow" setup to bring the remnant edges of thunderstorm complexes into our northwest and western zones Saturday and Saturday night, but the better chance (but still only roughly 30 percent chance) of daytime PoPs will hold off until Sunday into early next week as deeper southerly flow brings in better moisture profiles to fuel afternoon convection. At this point we are not anticipating enough clouds and rain around through the long term period to significantly blunt the warming trend associated with the building upper ridge in the vicinity. Ergo, we expect highs in the low to middle 90s to be rather ubiquitous come late this weekend and through early next week. Fortunately, the mini, early heat wave should probably not have major legs as model consensus is decent another front should sag in from the north later next week. /50/ && .PRELIMINARY POINT TEMPS/POPS... SHV 72 85 66 88 / 30 40 10 10 MLU 71 87 67 89 / 10 50 10 10 DEQ 63 83 60 86 / 80 10 10 10 TXK 67 83 62 85 / 80 50 10 10 ELD 69 85 63 88 / 50 40 10 10 TYR 69 83 65 85 / 80 50 10 20 GGG 72 84 65 87 / 50 50 10 10 LFK 73 87 69 89 / 30 50 20 30 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...Flash Flood Watch until 7 AM CDT Thursday for ARZ050-051-059>061- 070. LA...None. OK...Flash Flood Watch until 7 AM CDT Thursday for OKZ077. TX...Flash Flood Watch until 7 AM CDT Thursday for TXZ096-097-108>112- 124-125. && $$ 24/50