Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/18/19

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
915 PM CDT Wed Jul 17 2019 .UPDATE... Issued at 913 PM CDT Wed Jul 17 2019 Area of showers and thunderstorms just now reaching the western CWA, and have adjusted POPs accordingly. Removed POPs from the east earlier this evening as no activity developed there. No changes made to winds or temperatures at this time. && .SHORT TERM...(This Evening through Thursday Night) Issued at 300 PM CDT Wed Jul 17 2019 While mainly dry weather will persist, there will be the potential for isolated showers and thunderstorms across far eastern South Dakota and into Minnesota this evening, and additional isolated storms over central South Dakota overnight into Thursday morning. The potential remain for a few of these storms to become strong or severe, with strong winds or large hail. The HRRR has done the best so far at limiting the cloud and storm potential after 15Z, while other CAM solutions have shown more clouds and convection stalling temperatures in the low 80s. Will continue to mainly side with the HRRR with this forecast package, going slightly drier. Will continue to monitor the current mid clouds along the ND/SD border, and northeastern SD for additional development close to the surface trough with dew points near 70 degrees. Heavy rain (with PW values of 1-1.5in), strong winds, and large hail will be the main threats of any stronger storms that develop. Otherwise, hot and humid conditions will result in Heat Index values of in the 90s Thursday afternoon. A few spots across Lyman and Buffalo counties look to get near 100 degrees. Will hold off on any Heat Advisories for this area at this time, give the borderline conditions covering less than 1/2 of these counties. .LONG TERM...(Friday through Wednesday) Issued at 300 PM CDT Wed Jul 17 2019 The last in a series of shortwaves will cross the region mainly Friday night through Saturday night. With moderate instability and shear, some storms could be on the stronger side. A sprawling surface high pressure will build into the region behind the shortwave with cooler temperatures expected. The high pressure will also bring a much needed break from the active weather pattern. High temperatures early next week will mostly range in the upper 70s to the lower 80s, or about 5 to 10 degree below normal for this time of year. The cooler weather will not last long as an upper level ridge will begin building into the region toward the end of next week with temperatures returning to seasonal averages. && .AVIATION...(For the 00Z TAFS through 00Z Thursday Evening) Issued at 627 PM CDT Wed Jul 17 2019 For the most part, VFR conditions will prevail across the area tonight and through the day Thursday. Cannot rule out a few thunderstorms across the west and north tonight, but due to uncertainty, will just mention VCTS at KPIR and KMBG. Periods of MVFR cigs and vsbys are possible with any thunderstorms. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Parkin SHORT TERM...KF LONG TERM...SD AVIATION...Parkin
Area Forecast Discussion
National Weather Service Gaylord MI
1152 PM EDT Wed Jul 17 2019 .UPDATE... Issued at 933 PM EDT Wed Jul 17 2019 Thicker cirrus and mid-clouds have made some initial inroads into northern lower MI. Cloud cover has been increased. A few showers popped off as expected late this afternoon/early this evening between CAD and GRR, entirely staying south of this forecast area. Only a few blips are left of this activity. With high pressure moving off to the east, return flow increasing, and all sorts of heat/moisture upstream, the main forecast question is what to do with convective trends late tonight into Thu morning. There is no convection on this latitude upstream, and CAMs continue to slow the onset of deep convection upstream. Last couple of HRRR runs develop stronger convection along the IA border with MN/WI toward 3-4 am. This activity grows upscale, eventually threatening lower MI, but not til after 12z/8am. Other CAMs are in line with this thinking. So will sharply trim pops overnight, and even into the very start of the day on Thursday. How will this impact svr potential Thursday? This remains hazy. We do destabilize a bit before activity bodily moves in, but probably not enough, especially given expected increasing coverage of blowoff cloud cover. (More organized activity make also take off toward sw lower MI, leaving us with more disorganized activity along the northern flank - something that occurred upstream this afternoon.) Or, things could slow down a little further, and maybe then we would get some CAPE to work with. Or, the CAMs are wrong and little convection forms upstream tonight. A sunnier start to the day would make Thursday considerably more interesting. && .NEAR TERM...(Through Tonight) Issued at 409 PM EDT Wed Jul 17 2019 Impactful weather: Thunderstorm arrival possible early morning Synopsis: Surface high pressure is currently centered south of James Bay underneath large-scale subsidence provided at the ridge- trough inflection overhead. Further to the west in the northern Great Plains resides a surface cyclone along the U.S.-Canada border. This could extend further to the south and east throughout the period underneath modest WAA in the low-mid levels, driving pressure falls at the surface. Another cyclone lies in the lee of the Rockies, somewhat supported by relatively weak flow over mountains creating subtle vortex stretching/pressure falls. A quasi-stationary front extends from this cyclone east across the midwest and along the northern Ohio Valley region. A large, unstable airmass sits in place across much of the Mississippi Valley and Great Lakes with surface dewpoints in excess of 70 degrees and MLCAPE values ranging from 2,000-4,000 J/kg. An ongoing MCS in central Iowa moves ESE supported by this instability and 40-50 kts of effective bulk shear. Additional storm activity exists further to the north in Minnesota. Per the 1630Z Day 1 Convective Outlook from SPC, thunderstorm redevelopment is expected across portions of Minnesota and Wisconsin this afternoon and evening, which complicates forecast timing of potential thunderstorms later in the period. Forecast: Across the forecast area, fair weather cu is spread across portions of northern lower Michigan with temperatures in the lower- 80s for many. Mostly sunny skies are expected for the remainder of the evening with lows dipping into the lower-60s overnight. Cloud cover will increase during the overnight hours as thunderstorms approach from the west. The arrival of thunderstorms/MCS is still somewhat uncertain at this time due to the unknowns of how aformentioned ongoing/future convection will evolve. Regardless, the potential exists for storms to reach the forecast area before 12Z Thursday, although the main threats expected with these storms -- including damaging winds and hail, lightning, and heavy rainfall -- are most likely after 12Z across northern Michigan. && .SHORT TERM...(Thursday through Saturday) Issued at 409 PM EDT Wed Jul 17 2019 ...Warm and sticky air mass arrives to end the week... High Impact Weather Potential: Convective potential through the. period...including possibilities for severe storms (especially northern Lower Thursday) and heavy rainfall. Hot weather potential on Friday. Pattern Synopsis/Forecast: Generally low amplitude pattern to the westerlies across North America...quasi-zonal flow across the northern tier of states with some low amplitude short wave troughing over the northern Rockies...and the remnants of once TC "Barry" spinning through OH. There is a band of anomalously strong westerlies over the northeast Pacific (+3 standard deviations) sandwiched between a climatologically anomalous upper low over the Gulf of Alaska and ridging north of HI. This band of anomalous westerlies will spread across the northern tier of states during the latter half of this week...likely crossing Lake Superior and points north by Friday while broad upper ridging encompasses much of the southern CONUS in typical July fashion. A very interesting setup from a nasty convective windstorm point of view. Eventually this warm weather setup for the upper Great Lakes is forecast to break down later this weekend. East-west oriented surface boundary stretches across the lower Great Lakes/southern Lower MI back into the central Plains. Lots of moisture to the south of this boundary with widespread precipitable water values at or above 1.50 inches across much of the eastern half of the CONUS (widespread surface dew points 20C+ south of the boundary). 1019 surface high centered over northeast Ontario... which is actually setting up a fairly decent moisture gradient across MI this afternoon with precipitable water values around 0.9 inch adjacent to and north of the St. Mary`s River increasing to nearly 2 inches over far southeast Lower. Surface high shifts east tonight with increasing southwesterly boundary layer flow pointed into the upper Great Lakes for Thursday. This general idea will continue into the first part of the weekend though flow will be weaker...but better baroclinicity won`t be far away with northern Michigan likely on the northern edge of the burgeoning midwest heat wave forthcoming through the rest of this week. Primary Forecast Concerns: As usual convective evolution will be the main driver of forecaster angst into the weekend...and all of its downstream impacts. First order of business deals with likely MCS rolling east out of Wisconsin and into the forecast area Monday. Both a slight risk for severe storms and a slight risk for excessive rainfall have been posted for Thursday...the former depends on either the potential for some heating/destabilization ahead of the convective cold pool...or new development later in the day/evening along residual outflow boundary (though such a scenario may have a higher probability of occurring near/south of our southern forecast area border). Also have a suspicion that it may end up with more clouds/showers during the day with a subsequent impact on forecast highs (which have been tempered down about a category). Additional thunderstorm chances Thursday night will be dependent on how things evolve during the day but again the better focus may be over Lower Michigan. It appears that Friday may have the best potential for being the "hot" day especially over northern Lower where temperatures are likely to climb into the 90s and with dew points likely in the 70s heat indices at or above 100 possible over a good chunk of northern Lower. That will require heat related headlines if that were to come to pass. Initial round of height falls will push a boundary into the upper Lakes later Friday into Saturday... which should bring another threat for showers/thunderstorms to start the weekend. .LONG TERM...(Saturday night through Wednesday) Issued at 409 PM EDT Wed Jul 17 2019 High Impact Weather Potential: Minimal. Front sagging into the upper Lakes Saturday may still be in the vicinity Sunday...a continued chance for rain will be needed if the boundary is still lingering across Lower Michigan. But cooler and less humid air will filter into northern Michigan by the start of next work week. Consensus forecast trying to linger PoPs into Monday (as is typical) but not convinced that will be the case. Dry weather looks to be in the cards heading into midweek. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1152 PM EDT Wed Jul 17 2019 Showers/storms possible Thursday. High pressure will move off to the east, allowing warmer and more humid air to move northward. Showers and thunderstorms are expected to develop to our west late tonight, and these might impact the region after 14-15Z Thursday. This is looking slower and less certain than earlier. Generally kept the TAFs VFR, but brief restrictions are possible, especially during showers. Most recent guidance suggests cigs will not lower as much as earlier planned. Light e to se winds tonight. Increasing s to sw winds Thursday, becoming gusty at times. && .MARINE... Issued at 409 PM EDT Wed Jul 17 2019 Increasing southwest winds on Thursday will necessitate hoisting Small Craft Advisories for some Lake Michigan nearshore zones...but the pressure gradient is expected to weaken by Thursday night. This should lead to local effects (e.g., lake breezes) having the predominant effect on nearshore conditions through Saturday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...SMALL CRAFT ADVISORY from noon Thursday to midnight EDT Thursday night for LMZ341-344>346. LS...NONE. && $$ UPDATE...JZ NEAR TERM...KF SHORT TERM...JPB LONG TERM...JPB AVIATION...JZ MARINE...JPB
Area Forecast Discussion
National Weather Service La Crosse WI
1035 PM CDT Wed Jul 17 2019 .SHORT TERM...(Tonight) Issued at 301 PM CDT Wed Jul 17 2019 Focus tonight is on thunderstorm/flooding chances. A long-lived convective complex that evolved overnight has moved from northern IA southeastward into the stronger buoyancy/CAPE this afternoon with some general showers/storms reaching into northeast IA and increased clouds to the north. Short term model guidance has been quite inconsistent in handling the current convection, casting some uncertainty on trends through the evening. However, overall consensus seems to be for relatively quiet conditions through the rest of the afternoon in the wake of the MCV over Iowa. In response to an approaching shortwave trough from the northern plains this afternoon/evening, low-level moisture transport will increase this evening/interacting with the low-level boundary (although recent RAP runs have shown a weaker signal), with additional storms potentially firing across MN that may evolve into southeast moving complex overnight. The NAM Nest and ARW/NMM WRF runs have been consistent in this solution and the forecast is trended in that direction. However, especially given difficulty in high res guidance in handling ongoing storms and the significant spread in the high res guidance, confidence is pretty low on what transpires. Heavy rainfall would be a primary concern given the airmass, and several high res models have shown potential for several inches of rain, but this depend on whether storms repeat over the same areas. For now will maintain the Flash Flood Watch as is, but if shorter term trends support a more northern solution, it may need to be expanded into north-central WI. Hail or even an isolated tornado are possible early on if any storms form and root in the boundary layer along the boundary, but this would transition to mainly a wind threat overnight if an organized convective system forms. .LONG TERM...(Thursday through Wednesday) Issued at 301 PM CDT Wed Jul 17 2019 Heat and thunderstorms remain the concerns into the start of the weekend. Overnight storms should be on the way out Thursday morning with southerly flow developing. A surface boundary/outflow boundary may lie across the region and this could serve to focus additional storms later in the day or evening, mostly likely across western or central WI. Given the instability in place, some of these could be strong to severe. The surface boundary, possibly reinforced by storm outflow, will likely be waffling across the area through Friday, with potential for periodic storms in its vicinity. Somewhat stronger capping may help to suppress storms for Friday, though. The signal for heat remains quite strong Thur/Fri with the 17.12Z ECMWF continuing to indicate 925 mb temps around 30C during the afternoon hours into northeast IA/southwest WI. As a result, did upgrade portions of northeast IA and southwest WI to an Excessive Heat Warning. Kept the warning through Saturday, although confidence is lower for Saturday given some indication that the front/convection will sag south far enough to lower the threat for extreme heat. That will be re-evaluated as confidence grows. Farther north, a Heat Advisory was issued for Thur/Fri. Will have to keep an eye on potential impacts from storms/clouds, but given the airmass in place, even a few hours of warming should allow temps to rise quickly. Thunderstorm chances will linger into the weekend until the boundary finally shifts south by Sunday. A cooler and quieter northwest flow regime will develop early next week with more seasonable temps and drier air as surface high pressure builds across the area. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 1035 PM CDT Wed Jul 17 2019 Low level jet/sfc warm front interaction key for shra/ts development tonight. Varying answers in the short term models muddle the outcomes, but recent trends pointing toward late night convection, continuing through the overnight. Cigs: should hold VFR before anticipated convection moves in after 06z. Expect some drop into MVFR for awhile, with a return to VFR late Thu morning. Pretty good shot to scattered out for the afternoon. BKN cigs could/should return Thu evening with the west- east front hovering in the area. WX/vsby: expect shra/ts to blossom across the area overnight. Atmosphere supports heavy rain, so IFR/MVFR reductions likely in heavy rain. Could see a few higher gusts too. Storms look to exit by 12z Thu. By Thu evening, the front could light up again with shra/ts with impacts to the TAF sites. Winds: holding southerly through Thu. A few higher gusts possible around any storm. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Excessive Heat Warning from noon Thursday to 7 PM CDT Saturday for WIZ054-061. Flash Flood Watch from 7 PM CDT this evening through Thursday morning for WIZ032-033-041-042-053>055-061. Heat Advisory from noon Thursday to 7 PM CDT Friday for WIZ032>034-041>044-053-055. MN...Flash Flood Watch from 7 PM CDT this evening through Thursday morning for MNZ079-086>088-094>096. Heat Advisory from noon Thursday to 7 PM CDT Friday for MNZ079- 086>088-094>096. IA...Excessive Heat Warning from noon Thursday to 7 PM CDT Saturday for IAZ011-018-019-029-030. Flash Flood Watch from 7 PM CDT this evening through Thursday morning for IAZ008>011-018-019-029-030. Heat Advisory from noon Thursday to 7 PM CDT Friday for IAZ008>010. && $$ SHORT TERM...JM LONG TERM...JM AVIATION...Rieck
Area Forecast Discussion
National Weather Service Des Moines IA
629 PM CDT Wed Jul 17 2019 .DISCUSSION.../Tonight through Wednesday/ Issued at 409 PM CDT Wed Jul 17 2019 Tonight into Friday...The rain-cooled air looks to potentially rebound as the cloud shield from the MCS continues to press east this afternoon into the early evening. The tail end of the anvil should move east of Interstate 35 by 17z allowing at least the western portions of the CWA to rebound somewhat back into the middle to upper 80s before sunset. Winds continue to return to the south-southeast over western Iowa and expect this trend to persist tonight as the MCS moves east into Illinois. Expect the decent WAA to continue into tomorrow where the mixing increases past 15z Thursday and into the afternoon hours. This will put the dew points back into the the middle to maybe even upper 70s. Certainly the rainfall today potentially could add to the low- level humidity even though the state has been fairly dry lately and much of that rain was likely soaked up by crops. Regardless, confident in the ongoing max temp, dew point, and heat index forecast for Thursday. The potential convection late tonight into tomorrow remains highly uncertain. Another shortwave looks to move into northwest Iowa and into southern Minnesota past 06z Thursday providing some focus for thunderstorms in the this location. The mainstream models like the NAM/ECMWF/GFS are in fair agreement with the aforementioned location but the hires models remain inconsistent and thus untrustworthy for timing and location of any convection. The troublesome model forecast is the HRRR and RAP suggestion convection to develop by around 10-12z Thursday over central Iowa and if this occurs, concerned about seeing cooler temperatures again. But as mentioned, more confident in the hot and muggy conditions, especially with the strong cap in place tomorrow, and left out any mention of pops tomorrow past 12z Thursday. Alos, low confidence with the flash flood threat across the northeast as the convection today decreased that threat. However, there still remains a chance for heavy rain in this location and didn`t have the confidence to cancel before anything developed later tonight. Friday night into Saturday...a boundary looks to set up over northern Iowa/southern Minnesota during this time and will be the focus for thunderstorm development as the LLJ increases. The convective debris, if this does materialize, is likely to help cool the atmosphere across northern Iowa and thus a bit lower confidence in the heat advisory on Saturday. Saturday night into Sunday, the boundary stalls across Iowa and remains the focus for additional thunderstorms chances during this period. Heavy rain looks to be the main threat with warm layer cloud depths near 15kft, precipitable water values around 2 inches, and good moisture transport into the state. Plus, Corfidi vectors are somewhat oriented with the mean flow and the potential for training is possible. And with the type of rainfall rates we received today (2-4" per hour), could see similar rates Saturday night. && .AVIATION.../For the 00Z TAFS through 00Z Thursday evening/ Issued at 629 PM CDT Wed Jul 17 2019 A few showers or storms across the north this evening, mainly to impact KMCW or possibly KALO. Otherwise skies to clear off overnight, and could have some additional storms late tonight at KALO or KMCW toward sunrise. Winds to become more southerly to southwesterly into Thursday. Stronger low level winds may allow for some low level wind shear at times overnight tonight. && .DMX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning until 7 PM CDT Saturday for IAZ044>050- 057>062-070>075-081>086-092>097. Heat Advisory from 1 PM Thursday to 7 PM CDT Saturday for IAZ004>007-015>017. Flash Flood Watch through Thursday morning for IAZ006-007-017- 027-028-039. Excessive Heat Warning from 1 PM Thursday to 7 PM CDT Saturday for IAZ023>028-033>039. && $$ DISCUSSION...Podrazik AVIATION...Beerends
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
248 PM MDT Wed Jul 17 2019 .SYNOPSIS... Our summer monsoon appears to be in full progress with daily showers and thunderstorms continuing the next several days. The main threats from these storms will be locally heavy rainfall along with occasionally strong and gusty winds. Meanwhile, the additional moisture across the Borderland will also help bring afternoon temperatures down closer to normal for the next several days. && .DISCUSSION... While our overall flow pattern is not classic monsoon, we certainly have entered an extended stretch of monsoon-like conditions. Lower level moisture remain plentiful across the region as of this afternoon with surface dewpoints of 50 plus not only across the Borderland, but on all sides of the region as well. As a result, it looks like moisture will stay plentiful for several more days to come. As a matter of fact, the GFS keeps PW values elevated above 1 inch for most of the area well into next week. Aloft we are currently situated under a rather broad upper ridge that stretches across just about the entire southern half of the country. As a result, most storms that form the next few days will be primarily a result of instability caused by afternoon heating and lift provided by higher terrain. As is typical with this pattern, winds aloft remain rather light, thus resulting in slow moving storms that will continue to produce areas of localized heavy rainfall along with the possibility of some flash flooding. While storms will originally initiate over mountains, outflows produced by these storms will help generate new convection across the lowlands as the afternoons and evenings progress. Looking ahead into the weekend and beyond, the ridge aloft will begin to recenter over the intermountain west with troughing ensuing across the eastern half of the nation. Initially the lower levels will dry slightly by Sunday and Monday, but not enough to have a big impact on afternoon convection. However this pattern will eventually bring a stronger back door front into the area by late Monday. This will effectively bring a bigger push of deeper moisture into the area, thus increasing coverage and intensity of storms for early next week. && .AVIATION...Valid 18/00Z-19/00Z... Radar shows convection has been mostly confined to the higher terrain of the Gila Region, Sacramento Mountains, NW Chihuahua, and areas south of Van Horn this afternoon. RAP analysis indicates most of the Rio Grande Valley just above El Paso is again in a relatively minimum of instability, despite a marginal increase in low level moisture over the past 24 hours. While most HREF members did not handle early morning convection/leftovers very well, at couple members seem to depict ongoing convection (as of 20Z) well enough, and suggest that converging outflow boundaries will bring the threat of at least weak convection with gusty winds into the ELP/LRU area during the early evening hours. Stronger CAPE values at and just SE of ELP suggest there`s a better chance of deeper convection at ELP this evening, compared to yesterday. Also, the convection firing up south of Van Horn appears to be in an area of upper level divergence ahead of an inverted trough high aloft over the Big Bend region. This feature looks like it will remain nearly stationary before heading back to the east later tonight, but conditions are favorable for stronger convection south of Van Horn, which should push a stronger outflow boundary westward towards ELP tonight. NAM and other models suggest we may briefly see a SE wind shift and increase in low level moisture around 03Z this evening. Will hold VCTS for ELP now, but the best window for TSRA will be somewhere between 00Z and 06Z. && .FIRE WEATHER... A more active and moist monsoon pattern will set up over the next several days, but generally-speaking southwestern New Mexico will be the most favored for rainfall coverage. Temperatures will drop back down to within a couple degrees of normal through the weekend. Afternoon Min RH values will generally be in the 15 to 25 percent range, and above 30 percent in the higher terrain due to increased rainfall. Overnight recovery will be very good. Expect good overnight RH recovery, and generally favorable (Fair to Good) vent rates through the period. && .PRELIMINARY POINT TEMPS/POPS... El Paso 77 97 75 98 / 30 0 20 0 Sierra Blanca 68 95 68 95 / 30 10 40 10 Las Cruces 72 97 70 96 / 20 0 20 0 Alamogordo 70 98 70 96 / 20 20 10 20 Cloudcroft 51 81 51 77 / 20 40 20 50 Truth or Consequences 77 100 75 99 / 10 10 10 20 Silver City 65 89 66 88 / 30 50 20 30 Deming 72 97 70 95 / 20 0 20 0 Lordsburg 68 95 68 94 / 30 20 30 0 West El Paso Metro 76 95 75 96 / 30 0 20 0 Dell City 65 98 66 99 / 20 10 20 0 Fort Hancock 76 99 74 98 / 30 0 40 0 Loma Linda 65 92 65 92 / 20 20 30 0 Fabens 73 96 73 98 / 30 0 30 0 Santa Teresa 74 95 73 96 / 30 0 30 0 White Sands HQ 74 95 72 94 / 20 10 20 10 Jornada Range 71 97 68 97 / 20 0 20 10 Hatch 74 99 70 98 / 20 0 20 0 Columbus 71 96 71 95 / 30 0 20 0 Orogrande 71 96 70 96 / 10 10 10 0 Mayhill 55 88 55 86 / 20 40 20 50 Mescalero 56 88 56 85 / 20 40 20 50 Timberon 52 80 51 82 / 20 40 20 30 Winston 64 93 63 91 / 20 30 20 30 Hillsboro 71 97 70 96 / 10 20 20 20 Spaceport 68 98 67 97 / 20 10 20 20 Lake Roberts 58 91 57 89 / 20 40 20 50 Hurley 66 92 66 91 / 30 30 20 20 Cliff 62 96 61 94 / 20 20 20 30 Mule Creek 67 94 67 93 / 10 20 30 30 Faywood 70 92 68 91 / 20 30 20 20 Animas 69 98 70 93 / 30 10 30 0 Hachita 68 95 68 91 / 40 10 30 0 Antelope Wells 68 94 68 91 / 50 20 30 20 Cloverdale 65 88 65 85 / 50 20 50 10 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 27-Laney/25-Hardiman
Area Forecast Discussion
National Weather Service Hastings NE
701 PM CDT Wed Jul 17 2019 .SHORT TERM...(Today through Friday) Issued at 444 AM CDT Wed Jul 17 2019 Last night`s thunderstorms that passed through South Dakota into Iowa pushed a pretty strong outflow boundary through our area. This has led to increased cloud cover for some and light/variable winds for a large portion of the area. As a result, hourly temperatures have been running a solid 5 degrees cooler than expected in many places. Nevertheless, we will maintain the Excessive Heat Warning since we will have a couple more very hot days and relatively warm nights coming up. Thunderstorms are still expected to develop later today. Short term models have been gradually pushing back the timing through the day today, but the HRRR still shows a few storms developing in the McCook area, then slowly moving east-northeast through the evening. As mentioned yesterday, there is enough instability for severe storms, but shear isn`t great. Therefore hail and isolated downburst winds are the main threats. Whatever storms develop should dissipate after midnight tonight. Tomorrow is expected to be warm once again, and, in theory, there shouldn`t be much convective debris to keep us cooler like what happened today. The heat index is forecasted to peak at 102-111 degrees across the area. Thanks rising heights aloft, no thunderstorms are expected to impact the area. .LONG TERM...(Saturday through Tuesday) Issued at 444 AM CDT Wed Jul 17 2019 The heat continues on Friday. The model consensus shows a subtle decrease in temperatures as compared to Thursday...especially across northwestern portions of the area. That being said, it is only a couple degrees and heat-related impacts are expected to be similar to Thursday. Max heat index values are forecast to range from 98 to 109 degrees. An approaching front will bring some relief on Saturday, but the timing of its passage may be late enough that many locations still see heat index values around 100 degrees. This front will bring a chance for thunderstorms to the entire area Saturday evening into Sunday. After that, we are looking at a cooler and mainly dry stretch for next week. Daily highs may struggle to reach 80 degrees for some locations on Monday and overnight lows may drop back into the 50s. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 700 PM CDT Wed Jul 17 2019 Biggest issue will be LLWS potential for several hours. Most thunderstorm activity should remain southwest and south of terminals, but a slight chance prompted to mention in the forecast. High based storms may produce strong wind gusts from multiple directions. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Excessive Heat Warning until 10 PM CDT Friday for NEZ039>041- 046>049-060>064-072>077-082>087. KS...Excessive Heat Warning until 10 PM CDT Friday for KSZ005>007- 017>019. && $$ SHORT TERM...Billings Wright LONG TERM...Billings Wright AVIATION...Heinlein
Area Forecast Discussion
National Weather Service Grand Rapids MI
1003 PM EDT Wed Jul 17 2019 .SYNOPSIS... Issued at 325 PM EDT Wed Jul 17 2019 - Complex of storms will move in from the west early Thursday morning, with strong to severe storms possible. - Scattered storms redevelop Thursday afternoon through Friday could also become strong to severe. - Heat and humidity will build Thursday through Saturday, with heat index values exceeding 100 degrees in most locations by Friday. && .UPDATE... Issued at 1000 PM EDT Wed Jul 17 2019 Overall, the forecast is on track with no major changes planned at this time. As the low-level jet intensifies after midnight tonight, all eyes will be on NE/IA/MN in anticipation of elevated thunderstorm development. Considering the extreme instability present within the aforementioned region (00Z sounding from Omaha, NE shows >4500 J/kg or MLCAPE), widespread/severe convective development seems possible which would leverage concern for the eventual development of a forward-propagating MCS once the activity reaches Wisconsin...not unlike what transpired this morning across Iowa but further north. The activity may then manage to take advantage of a destabilizing boundary layer after sunrise and continue right into northern Illinois/Indiana/western Michigan. Should convection end up less widespread than currently expected, heat indices may make a run toward the 100 F mark tomorrow afternoon, especially south of I-96. Note that concern is also increasing for the potential for repeated rounds of heavy rain through Saturday, which we may have to address with the upcoming full forecast package. .DISCUSSION...(This evening through next Wednesday) Issued at 325 PM EDT Wed Jul 17 2019 Forecast concerns center around the extended stretch of hot and humid conditions that will last into the weekend and potential for thunderstorms, potentially strong to severe, from early Thursday morning through Friday. Weather should be fairly quiet this evening and most of the overnight hours as surface ridge axis shifts through the Central and Eastern Great Lakes. Could still see a shower or thunderstorm pop up this afternoon/evening, especially as the lake breeze converges with easterly flow. Potential is low and severe weather is not expected. Patchy fog may also develop again and low-level moisture lingers, especially for areas roughly south and west of Grand Rapids where winds will be lighter and skies will remain clearer longer. Upper shortwave and associated area of surface low pressure will lift through the Upper Midwest and Western Ontario tonight, pushing a warm front up into the Western/Central Great Lakes Thursday morning. Upper divergence and low-level jet nosing into WI/MN look to fuel MCS development over this area overnight. Latest hi-res models are keying in on this complex then moving towards Western Lower Michigan near/after sunrise. Instability will build behind the warm front and increase potential for strong storms to survive through the early morning, and even begin to regenerate with the onset of daytime heating by late morning. Damaging wind gusts look to be the main severe threat, with the greatest risk north of the Grand Rapids area where mid-level wind field will be stronger. Later in the day, after any needed airmass recovery, potential will be there for redevelopment of storms along any boundaries laid down by early-day MCS or small impulses embedded within westerly flow over the region. Severe threat through the afternoon and evening will be damaging winds in addition to large hail as thermal profiles cool aloft. Thunderstorms will also be possible Thursday night and Friday, with heat and high humidity keeping potential for strong to severe storms around. Coverage looks low however, especially over southern and eastern Lower Michigan as strong surface ridge over the Atlantic expands back through much of the Eastern U.S and into the Central/Southern Plains, and warms mid-level temperatures. Main weather impact over the next several days will be building heat and humidity. Michigan will be perched along the periphery of an extensive ridge sitting over much of the southern and eastern U.S, with flow around this feature feeding heat and humidity into the area. H850 temps will exceed 20C Thursday through Saturday, boosting surface temperatures into the upper 80s and 90s through this period. These temperatures will also be accompanied by dewpoints exceeding 70 degrees, which will send heat indices soaring. Thursday still looks very warm, but forecast temperatures were cut back slightly due to effects from morning convection and clouds. This keep heat index values below 100 for most locations (below heat advisory criteria), but still hot in the 90s. Bigger concern exists for Friday and Saturday, where lack of widespread convection/clouds leads to higher confidence with heat index values reaching or exceeding 100 degrees. Most areas should reach or exceed 100 degrees Friday, with areas near/south of I-96 remaining a concern for Saturday. Stress on a person`s body into the weekend will be intensified due to multiple days of hot weather, with warm/muggy nights where lows only cool into the 70s providing little time for a person to recover. Temperatures will cool Sunday and especially early next week as the ridge extending into the Southern/Eastern U.S. flattens and cooler air sinks into the area from Canada. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 705 PM EDT Wed Jul 17 2019 I expect VFR conditions tonight with light winds. Any convection assoicated with the lake breeze will dissipate by sunset and at this point the convergence line is east of Muskegon so that should not be an issue there even so. While the line is still west of Grand Rapids, it is unlikely when the lake breeze convergence line reaches Grand Rapids around 00z it will have convection on it anyway. Thursday I am really concerned about two possible squall lines crossing the TAF sites. I will admit I based my TAFs on the 21z run of the HRRR. So, unlike the way we normally just put VCTS in our TAFs that far out in time, this time I put them in the FM groups. These could be rather strong storms so I used the timing of the HRRR and put shifting gusty winds in the TAFS so show when, based on the current version of HRRR shows the storms crossing those TAF sites. These could be dangerous storms Thursday, please check tomorrow to see what we are thinking on these storms. && .MARINE... Issued at 325 PM EDT Wed Jul 17 2019 Winds and waves will remain fairly calm for the overnight hours. A complex of storms developing west of the Great Lakes is expected to track towards the Lake Michigan shoreline towards sunrise. Storms may remain strong as they moves through the area, and will pose a threat for lightning, and could generate locally strong wind gusts. Thunderstorms that redevelop during the afternoon and evening Thursday will also be capable of strong wind gusts, large hail, and lightning. Winds will increase out of the southwest tomorrow as low pressure lifts through Western Ontario. Wave heights will build into the 3 to 5 foot range north of Holland by Thursday morning and remain elevated through Friday. This will create a high swim risk for swimmers and pose a hazard to small craft. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement from Thursday morning through Friday evening for MIZ037-043-050-056. LM...Small Craft Advisory from 11 AM Thursday to 8 PM EDT Friday for LMZ846>849. && $$ UPDATE...Borchardt SYNOPSIS...HLO DISCUSSION...HLO AVIATION...WDM MARINE...HLO
Area Forecast Discussion
National Weather Service Lincoln IL
809 PM CDT Wed Jul 17 2019 .UPDATE... Issued at 809 PM CDT Wed Jul 17 2019 Long lasting MCS has shifted more into eastern Missouri and southern Illinois. Some showers linger over portions of the CWA this evening, mainly between I-72 and I-70, but should fade off in the next couple hours. Temperatures took a significant tumble with the rain in the western CWA, so some minor adjustments to the low temperatures were needed. Updated zones/grids have been sent. && .SHORT TERM...(This evening through Thursday) ISSUED AT 400 PM CDT Wed Jul 17 2019 Continued the excessive heat warning from this afternoon through Saturday afternoon over western CWA, and for central and eastern CWA from Thursday afternoon through Sunday afternoon. Heat indices peak from 100-105 this afternoon over western CWA, and 105-115 across CWA from Thursday thru Saturday during the afternoon. Heat index still approach 105 degrees Sunday afternoon south of the IL river, so the excessive heat warning may need to be extended into Sunday afternoon for rest of the areas southeast of Peoria. A strong to severe bow echo line of storms was moving southeast at 40-45 mph over west central IL, approaching western portions of Fulton, Schuyler and Brown counties at 345 pm. These storms associated with an MCS that had been tracking se across IA during the day, and recently moving into west central IL. The latest HRRR model is capturing this complex better now and leaned toward this model and HREF for track of system over western/sw CWA into mid evening as it gradually weakens by sunset. Severe thunderstorm watch posted for areas from Fulton to Sangamon counties sw thru 9 pm cdt. Muggy lows overnight in the mid 70s. More showers and thunderstorms could move into areas mainly north of I-74 late tonight into Thu morning. This convection to weaken during Thu morning over northern IL with heat and humidity building back into the area by Thu afternoon. Highs Thu in the mid 90s with afternoon heat indices peaking from 105-115 degrees with sultry dewpoints in the mid to upper 70s. .LONG TERM...(Thursday night through Wednesday) ISSUED AT 400 PM CDT Wed Jul 17 2019 A subtropical mid/upper level ridge that is nosing into IL on Thu will continue to build into the area through Saturday and continue the heat wave as temps and heat indices could rise a few degrees higher on Friday and Saturday. Isolated thunderstorms possible ne of I-74 during mid/late Saturday afternoon then 20% chance of convection over nne third of CWA Sat night with disturbances moving over the southern Great lakes with high pops will be. Better chance of convection on Sunday especially Sunday afternoon into Sunday evening as a frontal boundary slowly sags sse over central and southeast IL. Heat indices could still reach 105 se of the IL river Sunday afternoon with highs in the low to mid 90s, warmest from I-72 south. The frontal boundary will be pushing into the Ohio river valley overnight Sunday night into Monday with 20-30% pops over much of CWA into Mon, highest in southeast IL on Monday closer to frontal boundary. Temps closer to normal in the mid to upper 80s for highs Monday with dewpoints slipping into the 60s. Isolated showers/thunderstorms possible in southeast IL Mon evening, then dry cooler and less humid weather expected overnight Monday night thru Wed as dewpoints 1025 mb high pressure settles se into the Midwest. Highs in the low to mid 80s Tue/Wed with dewpoints slipping into the mid 50s to near 60 degrees. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 645 PM CDT Wed Jul 17 2019 MCS over central and sw IL and eastern central/se MO early this evening, was producing an area of rain showers along and west of highway 51 with isolated thunderstorms near SPI. Brunt of thunderstorms were in sw IL and eastern MO. This convection to gradually weaken as it tracks se across central IL next few hours into mid evening. MVFR conditions could briefly occur at SPI with the isolated thunderstorm next half hour. Mainly mid level canopy of clouds to decrease from nw late this evening and overnight with a light fog or haze possible overnight. Models show more convection over northern IL late tonight into Thu morning, and kept this nne of I-74 but will need to be watched in case it gets further south into our northern TAF sites especially PIA. Aside of SPI current NW wind of 10-15 kts with gusts around 25 kts expect fairly light sw winds less than 10 kts to veer south during tonight. Winds to veer SW and increase to 10-15 kts during mid/late Thu morning with gusts near 20 kts by Thu afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 1 PM Thursday to 7 PM CDT Sunday for ILZ038-043>046-053>057-061>063-066>068-071>073. Excessive Heat Warning until 7 PM CDT Saturday for ILZ027>031- 036-037-040>042-047>052. && $$ UPDATE...Geelhart SHORT TERM...07 LONG TERM...07 AVIATION...07
National Weather Service Jackson KY
1134 PM EDT Wed Jul 17 2019 .UPDATE... Issued at 1134 PM EDT WED JUL 17 2019 Showers and thunderstorms have generally diminished in intensity across eastern Kentucky over the past hour. There is still some additional activity popping up along outflow aligned northwest to southeast from central Kentucky. Expect this activity to gradually diminish with time as we continue to lose instability; however, will still have to watch for some localized training over the next hour or south across Rockcastle and Jackson counties. Will maintain some PoPs through dawn, as at least modest forcing will remain in place, although better chances look to be more confined to the southern half of the area, as indicated by the latest HRRR trends. Depending on any clearing that can take place overnight, at least some patchy fog will likely be seen through dawn as well. Temperatures currently in the low to mid 70s will not drop off much more through the rest of the night. Mainly freshened up the hourly trends through the night. Updates have been sent. UPDATE Issued at 839 PM EDT WED JUL 17 2019 Convection has fired up across portions of eastern Kentucky through this evening, mainly in response to an approaching surface trough, as well as lingering troughiness in the mid and upper levels. A more organized line developed near the I-64 corridor. This has moved southeast with time; however, additional convection has been developing back towards central Kentucky, and will have to watch for training and localized flooding concerns. Some of the more intense cells have also contained some gustier winds. Another broken line of storms has fired up along and just south of a line from London to Somerset. Will also have to watch for training with this line. Have freshened up the PoPs through the overnight period, with CAMs indicating continued convection to contend with well into the night. Storms should gradually weaken with time, as we lose instability. Updates have been sent. && .SHORT TERM...(This evening through Thursday night) Issued at 419 PM EDT WED JUL 17 2019 Showers continue to generally increase in coverage this afternoon across eastern Kentucky, but weak lapse rates above a couple thousand feet off the deck have hindered more robust/deeper convection. Have therefore seen rain drops maintain more of a tropical nature in terms of small drop size. Rainfall amounts have remained at or under 1/2 an inch today owing to this and transient cells off to the east along an upper trough. Additional activity will push into the Bluegrass region and northeast Kentucky late this afternoon along a surface boundary, which did cause some high water/flooding concerns earlier today in and around Cincinnati. Given the lack of deep instability and aforementioned storm motions, not expecting much if anything in the way of flooding concerns across the eastern portion of the Commonwealth. Isolated storms will be possible through tonight as moisture and a surface wave linger about. While most locales will remain rain- free overnight, low clouds will keep warm and muggy conditions in place with lows in the low 70s. Not expecting a great deal of fog development at this time due to the low clouds, but will have to monitor for any breaks in the clouds. Rising heights will build overhead as upper ridging noses in from the west Thursday. Abundant moisture and an inverted trough remaining nearby will keep isolated to scattered shower/storm chances in play into the afternoon. These will diminish from west to east through the day as temperatures warm back into the mid- upper 80s. .LONG TERM...(Friday through Wednesday) Issued at 419 PM EDT WED JUL 17 2019 The primary forecast issue in the extended is going to be the heat. Well above normal temperatures are forecast across the area to end the week and on into the upcoming weekend. Highs on Friday and Saturday are expected to max out in the lower 90s. Heat indices on both of those days will top out between 99 and 106 degrees. An excessive heat watch is in affect to address this oppressive heat. Precipitation chances were a bit difficult to pin down this go round. In general, the blended model data seemed to be overdoing the precip at times, as there were periods when the GFS and ECMWF had little if any precip in the area, while the blend had showers and storms everywhere. Due to the uncertainty, used a modified version of the NBM data, with adjustments made toward the more reasonable looking GFS and ECMWF models. At this time, the model data suggests that the rain will first begin on Saturday, along the TN, and VA borders. By late Saturday night into early Sunday morning, a sluggish area of low pressure that is forecast to be positioned to our southeast, will begin interacting with a southward moving frontal boundary. This combination of these two systems, combined with ample low level moisture, should lead to the highest rain chances we`ll see in the extended. The front mentioned early may even stall out across the area on Monday, which would bring a very good chance of showers and storms to eastern Kentucky. After a decent period of rain MOnday and Monday evening, a ridge of high pressure is progged to push southward across the Ohio and Tennessee valley regions. This in turn would finally dislodge the previously stalled front. Once that boundary is pushed out of the area, we should see a period of dry weather to finish out the extended. High temperatures may be quite a bit cooler the first few days of next week, as cooler air filters in behind the departed front. Highs next Monday, Tuesday are forecast be in the mid 80s and lower 80s respectively. Nightly lows to begin the period will be quite warm, with min readings in the lower 70s on tap. After a transition Monday night, when lows are forecast to be in the mid to upper 60s, the cooldown will be felt, with lows in the lower 60s expected for Tuesday night. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) ISSUED AT 839 PM EDT WED JUL 17 2019 Scattered to numerous showers and thunderstorms will threaten across eastern Kentucky through 06z, before these generally diminish across the area between 06 and 12z. IFR or worse conditions will accompany the stronger cells. Model guidance indicates some IFR stratus to develop across the area following the convection between 09 and 12z, with lower clouds likely lingering through 14-15z, before lifting. Scattered convection will threaten once again across far eastern Kentucky during peak heating, but will leave out any mention for now, until later forecasts. Winds will generally average around 5 kts or less outside of any direct hit from passing thunderstorms through early Thursday. Winds will then increase to 5 to 8 kts from the west to west southwest during peak heating. && .JKL WATCHES/WARNINGS/ADVISORIES... Excessive Heat Watch from Friday afternoon through Saturday evening for KYZ044-050>052-058>060-104-106>109-111-112-114-119. && $$ UPDATE...GEOGERIAN SHORT TERM...GUSEMAN LONG TERM...AR AVIATION...GEOGERIAN
Area Forecast Discussion
National Weather Service North Platte NE
621 PM CDT Wed Jul 17 2019 .SHORT TERM...(This evening through Thursday night) Issued at 106 PM CDT Wed Jul 17 2019 The 12z LBF sounding this morning indicated a h700mb temperature near 18C. The RAP model holds this warm air over swrn Nebraska tonight with cooler air aloft across scntl Nebraska where clusters of weakly sheared heavy thunderstorms will probably form, perhaps affecting Frontier and Custer counties for a few hours late this afternoon and this evening. Another weakness in the cap is across ncntl Nebraska this evening where isolated thunderstorms may form. Winds aloft are a bit stronger across ncntl Nebraska. Both areas pose a marginal or isolated severe weather risk for wind damage. Outflow from the storms across SD last night have pushed a weak cold front into wrn and ncntl Nebraska. The models show this front drifting south tonight and then lifting north Thursday. A surge of dry air is expected Thursday afternoon which will push the dryline east of highway 83. Temperatures in the low 100s will likely develop behind the dryline Thursday afternoon. Heat advisory conditions will likely develop east of highway 83 Thursday afternoon. The latest highlight continues the heat advisory through early Thursday evening east of highway 83. Lincoln county can drop out at 8 pm this evening. The thunderstorm forecast this afternoon through Thursday night uses a blend of the HREF, HRRR, RAP models plus the model blend. The temperature forecast uses a blend of the warmer NAM/ECM guidance and the dew point forecast leans on the sharper NAM guidance which pushes dew points into the lower 70s across ncntl Nebraska Thursday afternoon. .LONG TERM...(Friday through Wednesday) Issued at 306 PM CDT Wed Jul 17 2019 The best rain chance presents itself Saturday night as high pressure aloft transitions from the ern U.S. to the Wrn U.S.. The broad subtropical ridge centered over the Midsouth this afternoon will build east through Friday and then retrograde west and be centered over the srn Rockies Sunday. The transition is the result of a strong nrn stream wave moving through the nrn Plains Saturday. The disturbance will become a deep upper low centered over ern Canada next week with strong upper level high pressure across the Rockies. Chance POPs are in place Saturday night. Otherwise, just isolated rain chances are in place. Warm air aloft will remain in place through Saturday with h700mb temperatures of 15-18C. This can support 100F for highs if the mixing is deep enough. The temperature forecast Friday and Saturday is cooler with highs in the 80s and 90s. Sfc winds from the north and northeast are expected to limit mixing processes to around 800mb. The northwest flow aloft next week is strong and should pull cooler air into Nebraska Sunday through Wednesday. The rain chances are isolated for now but depending on the stability of the air, steering currents off the Big Horns and the Black Hills could send storm activity through wrn Nebraska. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 611 PM CDT Wed Jul 17 2019 VFR conditions will continue to prevail through this TAF period. The main concern will continue to be the threat for an isolated shower or thunderstorm this evening. Confidence is pretty low that a thunderstorm will impact KLBF, however, did mention VCTS for the KVTN TAF due to slightly higher confidence that a storm could impact the site. Have left any mention of LLWS overnight out as confidence is low that it will impact any of the sites at this time, however, it will be possible as surface winds decrease overnight with stronger winds aloft. && .LBF WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 1 PM to 8 PM CDT Thursday for NEZ007-010- 027>029-038. Heat Advisory until 8 PM CDT this evening for NEZ059. Heat Advisory until 8 PM CDT Thursday for NEZ071. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Thorne
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
847 PM CDT Wed Jul 17 2019 .UPDATE... 847 PM CDT No major changes planned to the going forecast for tonight or Thursday, though am somewhat concerned that convection tomorrow could throw a wrench in our going temperature forecast for at least portions of the CWA. Evening upper air data showed a reservoir of very steep lapse rates associated with an impressive elevated mixed layer (EML) plume advecting east into the Cornbelt. The very steep lapse rates juxtaposed over top the very rich theta-e air low level air mass is resulting in a large area of extreme instability over Nebraska east into Iowa. Guidance continues to struggle mightily in its attempts to resolve convection in this environment of extreme instability and subtle forcing. The widely varying solutions in the suite of convective allowing guidance lends itself to a low confidence forecast tonight into Thursday. GOES-16 simple water vapor RGB this evening shows a compact but fairly well defined vort max over south central South Dakota. While the bulk of model guidance may be struggling with convective placement, think the depiction of a developing 40-50kt low level jet pointing into northern IA/southern MN later tonight seems pretty reasonable. This strong low level jet should be quite effective driving parcels isentropically up and over the surface boundary currently over southern Iowa and likely lifting them to their LFC somewhere over northern IA or southern MN overnight. Given the extreme instability, very steep lapse rates, and modest effective shear profiles, it is quite plausible that a cluster of intense convection could develop overnight in this region. Assuming such development takes place, cold pool development could easily allowing for an MCS with forward propagating tendencies to take shape late tonight. The pool of better moisture and instability will likely begin to advect back east toward our area late tonight into Thursday morning. Given the expected orientation of the instability axis and the veering of the low level jet, would anticipate any MCS that develops overnight over northern IA or southern WI to begin to turn southeast taking aim on our CWA Thursday morning. Wouldn`t be hard to envision a scenario similar to today where convection survives the convective minimum during the mid-late morning and begins to re-intensify midday as it turns south and propagates into the instability axis on the eastern flanks of the expanding heat dome/cap. While describing such a potential is not difficult in an AFD, attempting to translate this potential into a 2.5km, hourly, deterministic gridded forecast is exceedingly difficult, particularly when models are not particularly helpful. Timing and potential track of this MCS are low confidence, but certainly the farther east you get in our CWA the greater the potential for convection to linger into the afternoon with trailing cold pool potentially keeping winds off the lake and slowing anticipated temp rebound. My gut instinct is that we could be dealing with convection into the afternoon with some severe threat Thursday, particularly eastern CWA with convective cold pool and cloud cover resulting in cooler than forecast temps over at least portions of the CWA. It is also entirely plausible that strengthening inhibition limits the ability of convection to develop southward into our CWA and temps verify or end up even a bit underdone given how well things heated up today outside of lake cooling and convection. Given the wide array of possibilities, not planning any changes to temp or heat index forecast for tomorrow. Am planning to introduce at least some slight chance pops into the afternoon hours Thursday and delay the onset of pops late tonight into Thursday morning just a bit. Will aim to get updated grids and derived forecast products out no later than 915 pm. - Izzi && .SHORT TERM... 258 PM CDT Through Thursday morning... Main concern is convective trends through early this evening and then overnight into Thursday morning. Upper 80s-low 90s temps away from the lake and dew points in the upper 60s-lower 70s (locally mid 70s) are yielding afternoon peak heat indices well into the 90s to around 100. This is similar to the heat and humidity that`s been prevalent in recent weeks and just a prelude to the bout of dangerous heat Thursday-Saturday. Convective concerns through late this afternoon/early evening continue to center on the two areas of interest covered in the earlier update. In the immediate near term, uncapped moderately unstable air mass (~1500 j/kg MLCAPE) and lake breeze convergence has yielded gradual uptick in convective coverage over northeast IL. Highest coverage has been over southeast Wisconsin and will likely top out in the scattered range near the lake breeze in IL and isolated in northwest Indiana. Lightning activity thus far has been somewhat lacking over northeast IL likely due to weak mid-level lapse rates and high freezing levels, but do expect lightning with the convection, as with a storm near ORD as of 230pm. Main threats with the lake breeze convection will be cloud to ground lightning, heavy downpours, and gusty winds owing to steep low level lapse rates (ORD gusted to 41 mph in TS over the airport as of 230pm). Severe weather appears unlikely given sub- marginal deep layer shear and aforementioned weak lapse rates. There should be a large diurnal component to these storms as their pulsy nature should be conducive for quicker decay and then loss of lower level instability this evening. Attention then turns to the longer lived organized MCS over eastern Iowa that 12z guidance essentially didn`t know was there. Due to this factor, we`ve had to rely almost exclusively upon observational trends for this portion of the forecast. Latest satellite, radar and lightning data trends do continue to suggest that northern portions of the linear MCS are on a gradual weakening trend. Meanwhile, the more intense portion of the linear MCS will bow toward the southeast into western Illinois due to: position of RIJ on latest radar mosaic; southeast forward propagating Corfidi vectors; existence of a northwest to southeast instability gradient over the region due to much steeper lapse rates farther west; and most supportive deep layer shear aiming farther southwest. It`s therefore appearing that strong/severe risk will most likely stay west of west/southwest CWA, though we`ll certainly need to closely monitor trends. Most likely threat area, if any, for strong winds with the MCS would be south of I-80 into north central and central IL. Current extrapolated radar indicates that at least rain/thunder have a decent chance to push into the western 1/3 or so of the CWA toward and after 4pm until about 7pm. With plentiful MUCAPE reservoir available through the night tonight, will have to watch for festering convection behind the decaying complex discussed above. However, subsidence and lacking trigger could keep renewed development isolated at most. Yet another complex of showers and thunderstorms is expected to affect the area Thursday morning from the predawn hours near Rockford and exiting east of northeast Illinois and northwest Indiana. Considering the poor handle on today`s linear MCS, confidence is medium on occurrence, though the 12z HREF CAM suite did have pretty solid agreement aside from 12z HRRR in bringing the MCS across the northern half of the areas. Have lower confidence on how strong the expected linear complex will be as it likely moves across the northern half of the area, driven by forward propagating Corfidi vectors toward the southeast. Strong/severe gusts would be possible if it remains intense. In addition to wind threat, we will also have to monitor for training potential at the SW end of this MCS as strong WAA will persist through Thursday morning which could result in isolated flooding issues, mainly in the upwind-propagating portion of the MCS likely across our western counties. Turning back to strong/severe potential with this MCS, despite the CAM guidance showing general weakening trend over the area Thursday morning, much longer maintenance of intensity of IA MCS this morning than expected adds concern for tomorrow morning`s expected/likely MCS remaining severe. There will be more than sufficient MUCAPE to feed on, a strong LLJ for maintenance, much steeper lapse rates (8-9 Celsius/km in 700-600 mb layer), and sufficient effective bulk shear, especially with northward extent. Would expect a gusty (30-40+ mph) west-northwest wind shift/outflow even if the complex is on a slow weakening trend, followed by a brief period of northeast winds near Lake Michigan and east-southeast over north central IL. If MCS remains severe over the CWA, may need to watch for wake low potential behind it. Winds will quickly come around to southerly behind the morning variability with the MCS, and gusty southwest (20-25+ mph) by mid day, which should jumpstart the recovery for the oppressive heat and humidity in the afternoon, after possible delay to the warming in the morning especially north of I-80 and near Lake Michigan. Castro && .LONG TERM... 258 PM CDT Later Thursday through Tuesday... The dangerous heat and humidity continue to be the main focus through Saturday. We have converted the excessive heat watch to a warning for most of northern IL, with the exception of the northern tier of counties along the WI state line where a heat advisory remains. A round of morning thunderstorms is probable across northern IL on Thursday. While the cool outflow from this activity may result in a slower onset of the oppressive heat and humidity for portions of northeastern IL Thursday, it does appear likely that the area will heat up quickly during the afternoon as some breezy southwesterly winds (gusts ~25 mph) develop over the area. These breezy conditions are likely to allow the hot and humid conditions to advect in over northeastern IL during the afternoon. Therefore, it is currently anticipated that high temperatures into the mid 90s and heat indices of 105+ will reach all the way to the lakeshore by late afternoon. The only possible caveat to this thinking is if we experience any renewed afternoon thunderstorm development along the remnant outflow boundary. This possibility, while not likely, can not be totally ruled out since the area should be only weakly caped to convection Thursday afternoon. If this were to occur, some areas near the lake could remain cooler than currently forecast for much of the day Thursday. Nevertheless, it appears that most, if not all, of the area will experience the heat by Thursday afternoon and will peak on Friday and continue through Saturday. This should result in 2 to 3 days of heat indices near 110. For this reason we have opted to go ahead with the excessive heat warning for much of the area. While a heat advisory remains in place over the northern tier of IL counties, conditions here will not be all that much better than areas in the warning. In fact, it is possible that portions of the advisory could need to be included in the warning in the future. Overall, the main message for the area is that the hot temperatures (well into the 90s) are expected to combine with very high dewpoints (in the 70s) to result in dangerous, potentially life threatening heat conditions. Also with very warm nighttime temperatures, there will be little to no relief from the heat until Saturday night or Sunday. A cold front is likely to drop southward across the area sometime Saturday night or Sunday. With this front, there will be a decent chance of thunderstorms over the area. Given the prefrontal environment, these storms will likely be heavy rain producers, and have the potential to be strong with gusty winds. In the wake of this front, expect cooler and less humid conditions to overspread the area on Sunday, and persist into next week. KJB && .AVIATION... For the 00Z TAFs... 702 PM...Forecast concerns include... Chance of thunderstorms early this evening. Wind directions early this evening. Chance of thunderstorms Thursday morning. Wind directions Thursday morning. Scattered thunderstorms have shifted east of ord/mdw late this afternoon and there may still be another shower or isolated thunderstorm over the next hour or so but this activity should continue to weaken/dissipate. Winds have become erratic after this activity moved through but should settle back to easterly over the next hour or so and then turn more southeast this evening and more southerly overnight...but confidence for this trend is only medium. There is another chance for thunderstorms Thursday morning with uncertainty for both timing and location. New thunderstorms are expected to form near the IA/MN border tonight with some activity in this area currently...and then turn southeast into northern IL either toward daybreak or through the mid morning hours. The high res guidance continues to fluctuate as to how far southeast this convection will move and when. Adjusted timing a tad later based on the most recent trends but maintained previous vicinity thunder. Timing will likely be uncertain until this activity forms and trends emerge either later this evening or overnight. If this activity continues through the terminals there will likely be a large outflow shifting winds northwesterly but winds will probably turn northeast then southeast. Previous tempo for northeast winds seem reasonable. Assuming any thunderstorms that do arrive in the area dissipate midday...winds should turn southwesterly by early afternoon and become gusty. cms && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Excessive Heat Warning...ILZ008-ILZ010-ILZ011-ILZ012-ILZ013- ILZ014-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032-ILZ033- ILZ039...noon Thursday to 7 PM Saturday. Heat Advisory...ILZ003-ILZ004-ILZ005-ILZ006...noon Thursday to 11 PM Friday. IN...Excessive Heat Warning...INZ001-INZ002-INZ010-INZ011- INZ019...noon Thursday to 7 PM Saturday. 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
632 PM EDT Wed Jul 17 2019 .SHORT TERM...(This evening through Thursday) Issued at 332 PM EDT WED JUL 17 2019 Models have been all over the place for the tonight time period in attempting to resolve what is going to happen, with some models finally coming back into agreement of much of the U.P. seeing this activity. That said, it appears that the NAM and RAP has a better/more realistic view of how it`ll all evolve, with timing remaining one of the bigger questions. The HRRR keeps pushing the timing of the main cluster back further and further, waiting until the pre-dawn hours to cross the heart of Upper Michigan. Wasn`t entirely sold on that, so went with the NAM/RAP timing. However, it is worth noting that confidence in all of this falls into the medium range at best, and is still within the realm of possibilities that it all busts and the U.P. ends up in the min QPF area. If this does play out as currently anticipated, then copious amounts of atmospheric moisture, with even higher PWATs expected to advect in, will allow for many locations to receive heavy rain; with the progressive movement though, flooding concern is low. As this activity pushes eastward tomorrow, look for a break in the activity until later (toward evening; see below for more details). Lows tonight will remain rather warm for the U.P., with widespread lows in the 60s, coupled with humid conditions. The warmth and humidity continues tomorrow with widespread 80s, upper 80s for the western two-thirds. .LONG TERM...(Thursday night through Wednesday) Issued at 408 PM EDT WED JUL 17 2019 Starting off on Friday, expect some of the highest temperatures Upper Michigan has seen this year so far. Widespread 90s are expected with the exception of along the Great Lakes and Keweenaw. With dewpoints in the mid 60s to low 70s, heat indexes will approach 100 degrees throughout Upper Michigan, especially in Menominee County. Some relief is expected into the weekend as a cold front pushes across the CWA Friday night. Upper Michigan will remain on the southern portions of the jet stream, with precipitation chances scattered through the weekend. An extended period with NW flow and an eastern trough is then expected to develop, leaving much more comfortable temperatures through next week with minimal precipitation chances beyond Monday. Thursday night, a chance of for showers and thunderstorms remain, mainly south and along the WI border as a stalled front remains across the area. Upper level shear remains up to 40 knots, leaving the chance at a few stronger storms. Depending on how convection behaves through the day Thursday will play a factor to some degree Thursday night. The bigger threat is perhaps an extended period of heavy rainfall lasting into the evening with up to 2 inches falling through the morning on Thursday. On Friday, expect a hot and humid day leading to afternoon showers and thunderstorms as a shortwave trough passes through the area Friday evening. Forecast soundings continue to show an elevated cap that should be able to mix out through daytime heating. Models appear to be converging on the idea of most convection remaining south along the WI border and into WI. CAPE across Upper Michigan is lacking as the 3000+ J/kg remains into WI. Into the weekend, a few scattered chances at precipitation remain. On Sunday, a high pressure ridge across the desert SW will amplify a ridge across the western CONUS allowing an eastern trough to develop. Upper Michigan remains along the bifurcation point allowing cooling temperatures and NW flow through at least the mid point of next week. This pattern also looks to limit precipitation chances through next week as well. Overall, perhaps normal to slightly below normal for temperatures with reduced chances at precipitation into next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 632 PM EDT WED JUL 17 2019 Although VFR conditions are currently prevailing at the terminals, conditions will deteriorate later overnight as a large cluster of showers and thunderstorms moves through. Once these storms move through overnight, indications point toward LL stratus potentially lingering around into Thu afternoon. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 412 PM EDT WED JUL 17 2019 Fog continues to linger across portions of the lake, and is expected to increase in area again tomorrow morning behind convective activity expected to move through tonight. Additionally, winds have already been on the increase this afternoon in the western arm of Lake Superior, which will spread eastward overnight, prompting the issuance of Small Craft Advisories for the nearshore eastern sections by early Thursday morning. Winds will settle down as the day progresses tomorrow, dropping off to less than 10-15 sustained by tomorrow evening. Generally speaking, sustained winds of less than 20 knots will prevail through the remainder of the forecast period. As for convection, chances (after tonight) look to largely hold off until later this weekend into early next week. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...lg LONG TERM...JAW AVIATION...07 MARINE...lg
Area Forecast Discussion
National Weather Service Paducah KY
320 PM CDT Wed Jul 17 2019 .SHORT TERM...(Tonight through Friday night) Issued at 320 PM CDT Wed Jul 17 2019 We will be upgrading the Excessive Heat Watch to a Warning from Thursday through Sunday. This is primarily for 4 consecutive days of 105 heat indices over most of the region. A few locations may reach the daily criteria of 110, but this is mainly a duration play. Hopefully, we don`t get some rogue convection over the weekend to mess it up. In the meantime, we are monitoring for convection late this afternoon into tonight. An MCS over southeast Iowa is poised to slide down the Mississippi River into this evening. Latest HREF data indicates that it will die off before reaching our region. We also have convection developing over the Ozarks to our west. This is expected to push eastward and develop southward through the remainder of the afternoon. It will likely impact portions of southeast Missouri, and could push east of the Mississippi River before dying off later this evening. Given CAPE of 2500-3500J/kg, any storm could pulse up to severe levels, but with little shear, storm organization is not expected through this evening, so any severe storm should be brief and isolated. Locally heavy rainfall will be the primary threat with all thunderstorms through this evening. HRRR data from earlier today brought a combination of the Missouri convection and the MCS southeast through southeast Missouri and southern Illinois into west Kentucky this evening. This is plausible, despite the latest HREF data, so will keep decent chance PoPs going roughly over the southwest half of the area through the evening. The larger-scale models want to develop convection over the northeast half of the area overnight into Thursday morning, so will keep small chances there just to be safe. Just don`t want to get caught with all of this instability and no PoPs. The forecast is dry from Thursday afternoon through Friday night, as the upper ridge dominates the region. Am somewhat skeptical of temperatures climbing into the middle 90s with dewpoints in the mid and upper 70s, but will go with the National blend. Figure some locations will test the 110 heat index mark over southeast Missouri and southern Illinois Thursday afternoon, but most of the area should get to at least 105. Figure Friday`s numbers will be a degree or so lower as the moisture begins to mix out. .LONG TERM...(Saturday through Wednesday) Issued at 320 PM CDT Wed Jul 17 2019 Through most of the weekend, an expansive, capping ridge over the southern half of the CONUS will be in place, precluding most pcpn for the PAH forecast area. Meanwhile, with surface dewpoints in the middle 70s, and highs in the middle 90s (especially Sat), heat indices of 105 to as much as 110 are likely through the weekend for many locations. However, there are a couple of variables that could make the Sun forecast slightly less oppressive (at least in some areas). By the latter half of the weekend, mid level height falls are progged to have begun as the flow aloft across the CONUS begins a transition to an amplified ridge-west/trof-east pattern. As a result, the surface high temps on Sun may be a tad cooler (mainly east of the MS River) as a frontal boundary approaches the PAH forecast area. Possible isolated showers and tstms, plus increased cloud cover, may contribute to somewhat lower heat indices (mainly east of the MS River). On the hotter side of variance, there could be some pooling of high dewpoint air Sun, just ahead of the (cold) frontal boundary. All this will be considered when a decision is made as to what type of heat headline to have for the latter part of the week. Sometime early Mon, a surface wind shift to the northwest or north is suggested by the initialization blend, with a true airmass change not occurring until probably Mon night, as surface dewpoints drop into the 60s. Though the blend hung on to some minor PoPs beyond Mon night, it is believed that, in the new, cooler/drier airmass, shower and tstm activity is not probable enough to mention in the forecast for Day 6 night/Day 7 (Tue night/Wed). At this time, the medium range models/ensemble means appear to be in good enough agreement that a pleasant forecast of lows in the middle 60s/highs in the lower to middle 80s seems realistic for the middle of next week. && .AVIATION... Issued at 1245 PM CDT Wed Jul 17 2019 The low clouds have scattered throughout the area, but an MVFR ceiling could linger for an hour or so at KEVV or KOWB. KCGI and KPAH will be most likely to be impacted by TSRA as a complex of storms attempts to move southeast along the MS River and into west Kentucky. KMVN may also be in the mix for a TSRA late this afternoon or evening. There is some signal for convection to impact KEVV and KOWB near sunrise Thursday, but confidence is too low to mention at this time. Threw in some MVFR fog at KMVN late tonight, but most places should keep enough wind to prevent fog formation. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...Excessive Heat Warning from noon Thursday to 7 PM CDT Sunday for ILZ075>078-080>094. MO...Excessive Heat Warning from noon Thursday to 7 PM CDT Sunday for MOZ076-086-087-100-107>112-114. IN...Excessive Heat Warning from noon Thursday to 7 PM CDT Sunday for INZ081-082-085>088. KY...Excessive Heat Warning from noon Thursday to 7 PM CDT Sunday for KYZ001>022. && $$ SHORT TERM...DRS LONG TERM...DB AVIATION...DRS
Area Forecast Discussion
National Weather Service Springfield MO
623 PM CDT Wed Jul 17 2019 .SHORT TERM...(This evening through Thursday) Issued at 200 PM CDT Wed Jul 17 2019 A mid level shortwave trough over south central IA will move ese- se into western IL/east central MO by 00z/7pm. Most high res guidance has convection developing in varying degrees over our eastern cwfa. HRRR might have the best depiction of the evolution of the convection (maybe). In general best setup for lift from the wave will be late this afternoon and early this evening, 3pm- 7pm. Have seen some updrafts to our east struggle early this afternoon, but it looks like stronger convection may have a better chance during this time. Uncapped high cape/unstable atmosphere. Despite high pwats/moisture, some dry air aloft will be able to support stronger downdrafts/localized downburst with stronger convection if it develops. Don`t plan on any changes to the excessive heat headlines with the possible exception of south central MO. Heat index values 100-110 are common at reliable observation sites. .LONG TERM...(Thursday Night through Wednesday) Issued at 200 PM CDT Wed Jul 17 2019 No big changes planned. Might make some adjustments/upgrades to some south central MO counties for excessive heat headlines where dewpoints are progged to be somewhat higher. In any case, will continue heat headlines through Saturday. A pattern change is still expected next week with a strong upper ridge progged to build over the western CONUS. This will put our area in northwest flow aloft and it should support an eventual cold frontal passage with a drier and cooler air mass moving in late in the period. We may have to continue the heat headlines for some areas into Sunday, but in general cloud cover and eventually some showers/storms with the front should cool things down. Blended model guidance appears to be under doing rain chances late Sunday into Monday. Will watch fcst trends, but believe there will be fairly good, albeit short lived chances for precip during that time. Global models are more bullish with rain chances versus the fcst model blend in our database. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 620 PM CDT Wed Jul 17 2019 A ridge of high pressure over the region will keep skies mostly clear with VFR flight conditions through tonight and Thursday morning. Surface low pressure in the western plains will bring enough gradient across the Ozarks to bring gusty southerly surface winds again after sunrise. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...Heat Advisory until 8 PM CDT Saturday for MOZ082-083-090>092- 094>098-101>106. Excessive Heat Warning until 8 PM CDT Saturday for MOZ055>058- 066>071-077>081-088-089-093. KS...Excessive Heat Warning until 8 PM CDT Saturday for KSZ073-097- 101. && $$ SHORT TERM...DSA LONG TERM...DSA AVIATION...Hatch
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
806 PM EDT Wed Jul 17 2019 .UPDATE... The latest RAP model has mid level ridging continuing along the Gulf coast and most of FL overnight - while an axis of high pressure from the Atlantic stretches through central FL to the Gulf of Mexico. Forecast PWAT values run 2 inches and above for much of the night but begin to trend down to 1.8 to 2.0 inches toward dawn. Abundant moisture and light flow helped to produce an active day of storms with small hail...50 to 55 mph winds...and some downed trees in Levy County. Convection began early in the afternoon up north but has now shifted south and is starting to push toward the Gulf coast. Anticipate these storms continuing for the next hour or two then winding down. Will update the forecasts shortly to better reflect the near term conditions. && .AVIATION... 18/00Z TAFs. BKN-OVC mid and high clouds with TCU/CB dissipating by 03Z...with brief MVFR VSBY/CIGS PSBL. Then prevailing VFR with VCNTY SHRA/TSRA starting AFT 14Z and containing through the period. Mainly W winds and gusty with nearby TSRA become light and VRBL TIL late Thu morning when they begin to shift to SE then SW. && .MARINE... Onshore winds of 5-10 knots shift to east and southeast later tonight then become southwest and west Thu afternoon. Main concern will be thunderstorms with locally higher winds and seas. && .Preliminary Point Temps/PoPs... TPA 77 92 77 91 / 40 50 40 40 FMY 76 91 76 91 / 40 50 10 50 GIF 75 93 76 93 / 20 60 10 70 SRQ 76 91 76 91 / 40 40 30 40 BKV 74 92 74 92 / 40 50 20 50 SPG 77 92 77 91 / 40 50 40 40 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE/AVIATION/MARINE...Rude UPPER AIR...Shiveley DECISION SUPPORT...Mroczka
Area Forecast Discussion
National Weather Service Tucson AZ
903 PM MST Wed Jul 17 2019 .SYNOPSIS...Daytime temperatures will experience a decreasing trend through the weekend and into next week. A more favorable steering flow for daily thunderstorms will become established today. This flow pattern will become even more favorable early next week. && .DISCUSSION...A busy mid afternoon to early evening through Santa Cruz and Cochise counties. Moisture and elevated ML CAPE was decent over Tucson, but they had better shear and better support for valley storms. We needed a stronger outflow to take advantage (and indeed, we are currently keeping our eye on 25kt outflow currently trying to push in from the east). At any rate, debris from earlier complexes over Cochise and Santa Cruz counties will continue to generate light to moderate showers with a few embedded lighting strikes into the early morning hours. A good chunk of SREF plumes show both MU and ML CAPE above 1000 j/kg tomorrow afternoon with ensemble mean in the 800-1k range. HREF layer precipitable water probabilities are showing deepest / 1.5 inch values just west of Tucson tomorrow afternoon. My guess is that we`re still going to have some convective inhibition to fight through in Eastern Pima county valleys and will require decent outflow to tap our convective potential. The HRRR probably has a good handle initially emphasizing storms south and southwest of Tucson tomorrow, with some development in eastern areas later as the atmosphere tries to recover. && .AVIATION...Valid through 19/06Z. Showers diminishing overnight with a few still possible mainly south of KTUS. Increasing thunderstorms again after 18/19Z. The greatest SHRA/TSRA coverage will be along the International border including KOLS/KDUG with lower confidence of impacts for KTUS. Surface winds diminishing overnight. Gusty and erratic outflow winds are expected with SHRA/TSRA. Otherwise, generally SCT-OVC clouds mainly 7-10k ft AGL through the forecast period. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...More abundant moisture will result in greater shower and thunderstorm coverage with the potential for locally heavy rain, especially from Tucson south and eastward. Any storms that develop will have the potential to produce locally heavy rainfall, as they are also slow movers. Thereafter, a fairly typical monsoon pattern with enhanced moisture will continue into next week with isolated to scattered mainly afternoon and evening showers and thunderstorms. Expect brief strong, gusty and erratic winds near thunderstorms. Otherwise, 20-foot winds will be mainly under 15 mph. && .PREV DISCUSSION... /issued 210 PM MST Wed Jul 17 2019/ Satellite imagery continues to show the decaying complex of storms south of the border in Sonora, Mex. A well developed MCV is making its way across the Gulf of California. The complex moistened the lower levels of the atmosphere with widespread dewpoints in the 60s (and even 70s in spots) across the deserts. 12Z KTUS sounding came in with PW`s around 1.3 inches which is in the 80th percentile (approx) along with decent mixing just above the surface. Latest hi-res deterministic and probabilistic guidance (HRRR, HREF, NBM, and UA WRFs) still indicative of a busy afternoon with initiation in the usual mountain spots south and east of Tucson. Good ensemble agreement showing the bulk of the activity across Cochise, Graham, and Greenlee Counties after 21Z, but outflow driven convection can`t be entirely ruled out either in/around Tucson in the afternoon and early evening hours. There isn`t spectacular steering flow in place today (5-10 kts), which will result in nearly stationary storms throughout the rest of the afternoon. Locally heavy rain/gusty winds/lightning are the primary threats. Steering flow is poised to become more favorable into the weekend and early next week, allowing for greater storm organization and rates of motion. Per the GFS and ECMWF 500 hPa height anomaly forecasts, the monsoonal ridge is expected to be in its prime location by late in the weekend/early next week, transporting much more impressive moisture values into Arizona. We can reasonably say that the monsoon flow and moisture pattern is here to stay. With dewpoints on the rise, temperatures will be less hot. KTUS has yet to reach the 100 degree mark today, a stark difference from the 110 degree day achieved yesterday. As the monsoonal pattern continues settling into its most favorable position, coupled with higher atmospheric moisture content, temperatures can be expected to top off between the upper 90s and low 100s. && .TWC WATCHES/WARNINGS/ADVISORIES...None. && $$ Meyer/L Visit us on Facebook...Twitter...YouTube...and at