Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/23/23


Area Forecast Discussion
National Weather Service Gaylord MI
1147 PM EDT Thu Jun 22 2023 .UPDATE... Issued at 1106 PM EDT Thu Jun 22 2023 Current forecast largely remains on track with quiet weather in place. Have nudged up low temperatures a few degrees for tonight as some mid/high cloud is expected to slide overhead from SE to NW overnight. Overnight temperatures are expected to dip into the upper 50s across most interior areas of northern Michigan with slightly warmer temperatures in the low 60s closer to the lakeshores. && .NEAR TERM...(Through Tonight) Issued at 420 PM EDT Thu Jun 22 2023 High Impact Weather Potential...minimal. Elevated fire danger into this evening. Weak surface high pressure continues to extend w to e across the northern lakes. Closer to this ridge, winds in northern areas are light/variable, but as you head south an easterly breeze becomes a touch gusty. Considerable cu has formed away from Lk Huron in northern lower MI, with lesser amounts in eastern upper. This cu is squatty here at APX. A little more vertical development is seen in nw lower MI, where convergence is higher along an inland-moving lake breeze. No signs of precip thus far. The air is generally hazy; at the moment GLR/TVC both have 5SM vsbys. We appear to be capped to deep convection, given current surface conditions. A meager 100-300j/kg of SbCape is present in central/western parts of northern lower MI. But a cap is represented by 725mb temps of 7-8C. It isn`t completely impossible for us to squeeze out a shower along lake breezes, but the chance isn`t worth a mention in the grids. HRRR smoke/haze progs suggest that the somewhat narrow plume of smokier/hazier air will continue to progress westward tonight. Haze will be mentioned outright in the grids in all but se sections. This back edge gradually migrates nw-ward tonight, and by 7 am the only remaining mention is in western Chip/Mack Cos. Trailing behind the better smoke/haze, layered mid-high synoptic cloud cover will push in from the se. Skies will be mostly cloudy by dawn in the se half of the forecast area. This will help keep min temps a little milder than they have been in that area. Lows in the 50s. && .SHORT TERM...(Friday through Sunday) Issued at 420 PM EDT Thu Jun 22 2023 HIGH IMPACT WEATHER POTENTIAL: Minimal attm...though rain/storms possible Saturday night into Sunday... PATTERN SYNOPSIS/FORECAST: Longwave troughing, with a handful of niblets in the flow, across the western US leading to southwesterly flow through the middle portion of the continent. Bulk of the activity is along/ahead of this region and its resultant surface reflection, which extends from Hudson Bay down into UT...amid a plume of deeper moisture (pwats greater than 1.5 inches) and a tighter thermal gradient. Ridging still trying to hold firm across southeastern Canada, including north of us...getting pinched by broad upper low to our south over TN. Confluence between these features keeping surface high pressure in place...as well as persisting the dry easterly flow (and subsequent smoke advection). Some of the moisture/cloud cover from the system to our south is attempting to make it into the Upper Great Lakes...but is still struggling to some degree. Otherwise...a surface BCZ stretches largely along the SE coast of the US (barring FL), back into TX, where there is still leftover nocturnal convection along the periphery of the very toasty subtropical ridge (850mb temps +30C...yikes!!). Upper low to continue to make a move northward through tonight and open up...but with potent energy currently offshore of SoCal quickly moving into the flow in the western US...anticipate our low will be a little more progressive than it has been. For Saturday...we may sit in between this...and the incoming trough as it rides over the subtropical ridge...which will be the next item of note in the forecast...and which could produce some rain and storms Saturday night into Sunday. This being said...there are still some slight differences in guidance that will keep some uncertainty in the forecast for the end of the weekend into early next week...and will likely avoid trying to get too into the weeds for now. PRIMARY FORECAST CONCERNS: Rain/storm concerns Saturday night into Sunday... Not out of the question there could be some shower activity across NE Lower...particularly near Saginaw Bay/east side of the interior higher terrain...on Friday afternoon, where there could be some deeper moisture spinning up in here from the south. Even so...we could still end up too dry in the lower levels to get much in the way of convection, though it`s not impossible a little sprinkle/shower may be able to spark along the lake breeze. Will have to see if anything actually does try to fire today, which could give us a bit of an indication if potential is there for Friday...though the setup should be slightly different with a bit more moisture around initially...which, if it were in the form of cloud cover, could limit diurnal heating (and subsequently, our potential for instability) to some degree. Non-zero potential again for lake breeze convective activity across NW Lower...but still not totally convinced we will get much of anything. A similar idea stands for Saturday afternoon...as we sit beneath some high pressure again between the two systems...though guidance derived soundings suggest that if we do manage to end up more moist than we currently expect (which I`m not going to hold my breath over), we could actually stand a chance of breaking the cap in a few places. Additionally, assuming winds switch around to a more northerly idea going into Saturday with that ridge slipping in...the focus for lake breeze convergence would likely shift back toward NE Lower again. Still watching the current radar/satellite to see if anything happens today...and will make note of it for the next few days` worth of forecasts. Things get more interesting for Saturday night into Sunday...as the upper low approaches from the west. Does appear that an E-W oriented boundary stalls out to our north...potentially near enough that it could be worth keeping an eye on...if we`re able to get convection to regenerate and drift eastward/ESE-ward along it. Not a sure bet by any means, though...but potentially something to keep half an eye on. Upstream convection expected Saturday night into Sunday ahead of the approaching shortwave trough. For now...there is some indication that this may try to roll in Sunday morning...and guidance would like to fire more convection later Sunday along the cold front itself. While I`d like to believe that idea...I`m also well aware of our tendency for storms to die out over the Lake...and/or for morning convection to linger cloudiness through the day, with potential to suppress later development. That being said, it`s not impossible that we could effectively prime the atmosphere with the early morning idea enough that any afternoon convection could actually do something...but this is a bit of an "if" for now...particularly noting that we`re talking about convection for 3 days from now. Additionally...worth noting that there could actually be some slightly better wind profiles Sunday in advance of the front than we`ve seen yet this summer...which could throw a bit of shear into the mix. Will certainly be something to watch the next couple days. .LONG TERM...(Sunday night through Thursday) Issued at 420 PM EDT Thu Jun 22 2023 HIGH IMPACT WEATHER POTENTIAL: Watching rain potential... PATTERN SYNOPSIS/FORECAST: Broad idea is for the upper low to be in/over our vicinity early next week...though guidance is still struggling a bit with how this evolves (how deep will the low be? how quickly will it move through?). Will have to keep an eye on this, given that a couple weekends ago, we had similar ideas of a cutoff low bringing rain...which ended up sitting right over us, with the precip donutting around us. Not that this is necessarily the expectation again...but it does throw a little bit of caution into the idea of ramping up messaging about the potential rain for next week. Even so...worth noting that WPC has us in marginal for excessive rainfall for day 5 (Monday)...though again...will have to see how this evolves. Even so...should be cooler under and behind this system, either way. Otherwise...beyond this trough...there are signals for the upstream pattern to turn a little zonal for a time toward midweek or so, as troughing attempts to move back into the western US...and additional energy treks through the northern stream of the flow...though again...still a lot of questions to be answered before jumping on any bandwagons. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1137 PM EDT Thu Jun 22 2023 VFR conditions are expected to continue across northern Michigan TAF sites through the issuance period as HZ previously restricting VSBYs continues to work northwest. Mid/high cloud is expected to spread into northern Michigan tonight into Friday, along with the potential for a few showers across mid-Michigan south of the northern Michigan TAF sites. Otherwise, calm winds overnight will gradually increase out of the east-northeast on Friday. Lake breezes will likely push inland from the lakeshores Friday afternoon before weak/calm winds are expected again Friday night. && .MARINE... Issued at 420 PM EDT Thu Jun 22 2023 High pressure continues over the far northern lakes. This is bringing mostly light, mostly easterly winds to the area. And this will persist into the start of the weekend. Advisories should not be needed. Se winds may ramp up more substantially on Sunday. && .APX WATCHES/WARNINGS/ADVISORIES... MI...NONE. LH...NONE. LM...NONE. LS...NONE. && $$ UPDATE...DJC NEAR TERM...JZ SHORT TERM...FEF LONG TERM...FEF AVIATION...DJC MARINE...JZ
Area Forecast Discussion
National Weather Service Charleston SC
1027 PM EDT Thu Jun 22 2023 .SYNOPSIS... An area of low pressure and associated front will persist across the Southeast through the end of the week. The front is expected to move offshore and high pressure will build in through the weekend, before another front approaches the area from the northwest early next week. && .NEAR TERM /THROUGH FRIDAY/... No significant changes made with the mid evening update. Additional showers an some thunderstorms will be pivoting up into the region during the overnight hours although recent HRRR runs have backed off a bit on the overall coverage. Will see. Meanwhile, we have been monitoring rainfall totals across Allendale, Screven and Jenkins counties. Currently running 1 to 3 inches over the last 6 hours or so...a little higher in Jenkins county. With another incoming round of heavy rainfall about to move into Jenkins county, we have opted to hoist a Flood Advisory for a good portion of the county. We will continue to monitor that area. Previous discussion... Closed upper low continues to spin over far eastern Tennessee/western north Carolina with an upper jet core that stretches from southern Georgia into Virginia. Surface low pressure sits across southern Georgia with a boundary that extends northeastward through central South Carolina. Upper jet entrance region forcing over top the boundary has focused most of the precip across our far western counties over the last several hours, with a lull continuing further eastward to the coast. Yet another short-wave impulse associated with the upper jet is looking to swing out of southern Georgia and into South Carolina later this evening and overnight. Expectation remains for another batch of showers and some thunderstorms to expand up into the CWA, mainly during the overnight hours. I`ve performed some PoP cosmetic tweaks to highlight relatively lower PoPs this evening, then ramping back up to likely-categorical for the overnight. No other changes to the forecast at this point. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... Friday through Sunday: Aloft, the upper low will continue to lift northward across the Ohio Valley and into the western Great Lakes, leaving the Southeast still well within prominent troughing on Friday. Then through the weekend, the trough will finally make eastward progress and shift off the coast by Sunday. At the surface, the nearly stationary boundary will continue to linger across the region Friday, then shift to the coast and offshore by Sunday. For Friday, the area will remain within a very moist atmosphere with precipitable water values approaching 2 inches. Then through Friday night and into Saturday, model consensus is that the bulk of the moisture will get nudged offshore, leaving the area in precipitable water values of 1.5 inches or less by Saturday afternoon. The end result is that Friday is expected to be the last really active convection day. We should see numerous to widespread showers and thunderstorms through the day, with a generally low severe threat and the potential for locally heavy rainfall and minor flooding. For Saturday only isolated to scattered showers and thunderstorms are expected, a notable decrease in coverage from the last several days. The by Sunday, we very well may not see any convection at all. Temperatures should be on a warming trend, with lows to mid 80s Friday, then upper 80s Saturday, followed by upper 80s and low 90s for Sunday. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Zonal aloft will briefly return Sunday night and Monday ahead of upper low across the Great Lakes that will help to carve out a trough along the Eastern Seaboard into the middle of next week. A front is expected to sweep through late Monday and Monday night bringing the best chance for convection during the long term period. Behind the front, model guidance supports a dry forecast from Tuesday onward. Temperatures will be near to slightly above normal, with highs in the upper 80s and low 90s common. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Terminals remain precip-free for the time being and largely VFR (although there has been some MVFR cloud cover passing through from time to time). Another round of showers and some thunderstorms will expand up into the region during the overnight hours, impacting the terminals in the 06Z to 10Z timeframe. Another lull takes shape Friday morning. But additional showers and some thunderstorms will develop late morning and through the afternoon. The same daily cycle we have seen over the last few days. Extended Aviation Outlook: Periodic flight restrictions in showers and thunderstorms are possible Friday evening and Friday night, including brief localized conditions IFR or lower. Shower and thunderstorm coverage will decrease over the weekend. && .MARINE... Tonight: A strong marine surge continues on the waters this afternoon with winds 20 kt with gusts to 30 kt common. Winds will diminish some overnight with the passage of the vorticity maximum late, but gusts to 25 kt still seem plausible through much of the night. The Small Craft Advisory has been extended until 6 AM Friday. Seas will average 4-5 ft. Friday through Tuesday: Winds across the local waters are expected to decrease quickly Friday morning and all Small Craft Advisories should be down by that time. Thereafter, a more typical moderate southwest flow will prevail into Monday with periodic surges due to the sea breeze and during the nighttime periods. Winds could be a bit stronger later Monday ahead of an approaching front, but should still remain below advisory thresholds. Seas should mostly be in the 2-4 ft range. Additional rounds of showers and thunderstorms can be expected Friday and Friday night with gusty winds and heavy rainfall producing visibilities below 1 NM at times. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 6 AM EDT Friday for AMZ350-352-354- 374. && $$ NEAR TERM... SHORT TERM... LONG TERM... AVIATION... MARINE...
Area Forecast Discussion
National Weather Service Cheyenne WY
525 PM MDT Thu Jun 22 2023 .SHORT TERM...(This afternoon through Friday night) Issued at 1210 AM MDT Thu Jun 22 2023 Included a portion of this morning`s discussion with convection initiation imminent across the region once again early this afternoon. Severe Thunderstorm Watch will be issued over the next hour and will include most of the same counties/cities as yesterday with most of southeast Wyoming outside of Carbon County affected and most of the western Nebraska Panhandle this afternoon and into this evening. Although activity maybe a bit more isolated today compared to yesterday, once the 700mb to 800mb temperature inversion dissipates this afternoon, thunderstorms will become stronger and push east and northeast through this evening. Large hail up to tennis ball size will be the primary concern. Although, noting some low level (0-2 km) helicity in the boundary layer as well with EHI around 2 to 4 from Albany county eastward towards the central and northern Nebraska Panhandle. Therefore, can not rule out one or two tornadoes with solid 0-3km CAPE values and decent surface moisture, although not quite as good as yesterday. Severe Thunderstorm Watch will be in effect until 9 PM this evening, but the western Nebraska Panhandle will see activity not starting until around 6 or 7 PM late this afternoon. More of the same for Friday with a greater risk for severe weather across the plains. SPC issued an Enhanced Risk for locations east of the I-25 corridor Friday afternoon and evening. With better shear, impressive ML and MUCAPE, along with a potent upper level trough moving through the area, Friday may be the busiest day of the week with all modes of severe weather expected, including tornadoes. Thankfully, flash flooding will start to become less of a concern as thunderstorms are expected to move relatively fast across the area. Will still have to watch training thunderstorms which may result in some flooding concerns. Previous Short Term Discussion... issued at 245 AM MDT Thu Jun 22 2023 Dilemma today will deal with timing of convection. Still seeing that mid level (700mb) capping inversion through 21Z or so before it breaks. HRRR and RAP simulated radar are in disagreement with convective initiation. HRRR shows the storms beginning west of the Laramie Range in Albany County roughly 19-20Z. RAP shows convection beginning more east across the southeast Wyoming plains from Cheyenne to Lusk...into the northern Panhandle after 18Z. Don`t think the severe storms will get going though until the mid level cap breaks...so storms may develop earlier...but not be severe until after 21Z. Storms will be severe with MUCAPE around 1500 to 1800J/KG across southeast Wyoming. 0-6km shear quite high with 40-50kts advertised on GFS soundings. Especially in Albany County where the HRRR is advertising the convection to start. Both the HRRR and RAP are concentrating the convection in the Platte/Goshen/Niobrara County area towards 00Z before it moves out into the northern Panhandle after 00Z. Better instability though will be down along the I-80 corridor however...so we will have to wait and see how this convection eventually develops. Better chances for severe storms still looks to be Friday when an approaching upper low begins to force the surface front north and east. GFS soundings showing much better MUCAPE around 2500-3000J/KG out in the Panhandle and around 2000-2500J/KG over southeast Wyoming. All modes of severe convective weather is possible today and Friday including a few tornadoes. Better chances Friday we believe with the better instability. SPC has Slight Risk areas outlined for both today and Friday for portions of the CWA. .LONG TERM...(Saturday through Wednesday) Issued at 1137 AM MDT Thu Jun 22 2023 Overall, no major changes to this forecast package, with possible high winds expected Saturday and continued unsettled weather early next week. Both the GFS and the Euro are in good agreement with mid to upper level low ejecting eastward across northern Wyoming through Saturday. Minor disturbance on the southern most flank of the cell is expected to dig across the region, kicking up wind speeds along the way. 700mb flow has winds increasing along these disturbances in excess of 45 to 55 knots with forecast soundings indicating those winds can mix down to the surface. In addition, the Random Forest Wind Model guidance has also been capturing this feature with good signals towards a stronger winds for the wind prone areas along the I-25 and I-80 corridors. Ultimately, gaining confidence for a decent wind event primarily on the I-25 corridor with the Craig to Casper gradients and the NBM v4.1 Probability of Exceeding 41kts increasing probabilities and echoing signals from other guidance. Main uncertainty will include the wind prone areas along the I-80 corridor, with 700mb winds keeping much further eastward. However, surface flow maintains a more favorable direction through the mountain gaps and the NBM v4.1 Probability of Exceeding 48kts hovering around a 50 percent. As a result, went ahead and left winds elevated across the wind prones in southeast Wyoming. Will need to think about a high wind watch in the next 24 hours if these trends continue. Active weather continues early next week, with an upper level trough makings its way from the western seaboard through to the Intermountain West. Strong to severe storms will be possible under this setup, with good moisture return across the region and PWATs just under 1 inch. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 521 PM MDT Thu Jun 22 2023 Wyoming TAFS...Another weather disturbance and abundant low level moisture will help produce thunderstorm development through early evening. Isolated thunderstorms will occur at Rawlins until 01Z, with occasional thunderstorms at Laramie and Cheyenne until 02Z, producing wind gusts to 40 knots along with visibilities to 2 miles and ceilings from 2500 to 3500 feet AGL. Overnight tonight, areas of fog and low clouds will develop producing visibilities from 2 to 5 miles and ceilings from 1500 to 2500 feet AGL from 06Z to 15Z. Nebraska TAFS...Another weather disturbance and abundant low level moisture will help produce thunderstorm development early this evening. Occasional thunderstorms will occur until 03Z, producing wind gusts to 45 knots along with visibilities reduced to 2 miles and ceilings near 2500 feet AGL. Overnight tonight, areas of fog and low clouds will develop between 04Z and 15Z, reducing visibilities to 2 to 4 miles along with ceilings from 1500 to 2000 feet AGL. && .FIRE WEATHER... Issued at 1137 AM MDT Thu Jun 22 2023 Minimal fire weather concerns through this weekend. Although much drier air will push into central Wyoming starting on Friday and lasting through the weekend, current green up conditions and recently rainfall will inhibit any major concerns for the near future. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...TJT/GCC LONG TERM...MD AVIATION...RUBIN FIRE WEATHER...TJT
Area Forecast Discussion
National Weather Service Green Bay WI
1053 PM CDT Thu Jun 22 2023 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Friday Issued at 246 PM CDT Thu Jun 22 2023 Various impacts from smoke and precipitation trends on Friday afternoon will be the main forecast concerns. SCT-BKN Cumulus clouds developed with the heating of the day, especially in north central WI, and in parts of the Fox Valley. Satellite also showed a thick layer of smoke edging into eastern WI. Smoke trends/impacts: thicker smoke will slowly advect westward and cover most of NE/EC WI by later tonight/Friday. Smoke models suggest that the smoke will reach the surface in parts of eastern WI late tonight into Friday, with air quality concerns and possible minor visibility restrictions expected. An Air Quality Advisory remains in effect through late Friday evening. Have adjusted sky grids to account for the thicker smoke, and made minor downward adjustments to temperatures in eastern WI on Friday. Precipitation Trends on Friday Afternoon: A weak cold front is expected to sag into the northwest part of the forecast area on Friday afternoon, and may be enhanced by a lake breeze off Lake Superior. PWATs will increase to around 1.5 inches and CAPE will build to around 500 j/kg in NC WI, so scattered afternoon showers and thunderstorms should develop. Rest of the Forecast: daytime cumulus should diminish this evening, but lingering mid-level moisture could result in patchy cloud cover through the night and into Friday. Like last night, patchy ground fog is expected to develop in low-lying areas late. Lows will fall into the middle 50s to lower 60s. Highs on Friday will be in the middle 70s to lower 80s lakeside, and 85 to 90 inland. Relative humidity will remain on the low side during the daytime. .LONG TERM...Friday Night Through Thursday Issued at 246 PM CDT Thu Jun 22 2023 A pattern change is expected as the 500mb ridge across Ontario breaks down while an upper low moves into Wisconsin on Sunday. This pattern shift will result in much cooler temperatures along with the chances of showers and thunderstorms Saturday into the first part of next week. For Friday night, per coordination with the short term forecaster did add areas of smoke and haze through Saturday morning. The HRRR model did show the greatest concentration of smoke across northeast Wisconsin. There is also a chance of showers and thunderstorms across the north. For Saturday, latest model runs continue to slow the onset of the rain. Have decreased the rain chances which will result in a dry day across the east. If models continue the slower trend tonight, may be able to decrease them even more. It is uncertain on the trends of the smoke and haze Saturday morning, thus ended it at 18z for now. The chances of showers and thunderstorms increase Saturday night as the upper low approaches from the west. Showers and storms will continue at times Sunday into Monday as the upper low moves overhead Sunday, then east of the area Sunday night and Monday. Rainfall amounts of a half inch to one inch are likely in many spots. This rainfall will be helpful for the drought stricken area. The latest drought monitor has parts of the area in the Moderate Drought (D1) classification. Low confidence in the low chances of rain on Tuesday, otherwise high pressure will bring dry conditions Tuesday night and Wednesday. The next system will bring a chance of rain Wednesday night and Thursday. Above normal temperatures are expected Saturday, then high temperatures should run below normal through the middle of the week. && .AVIATION...for 06Z TAF Issuance Issued at 1052 PM CDT Thu Jun 22 2023 Smoke from Canadian fires will move into Eastern Wisconsin overnight and Friday. It should be mostly elevated above the ground, but could mix down at times and produce visibilities of 3 to 5 miles east of an Iron Mountain to Waupaca line. Otherwise VFR conditions should continue through Friday with high based Cumulus clouds in the afternoon. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM.....Kieckbusch LONG TERM......Eckberg AVIATION.......RDM
Area Forecast Discussion
National Weather Service Grand Rapids MI
753 PM EDT Thu Jun 22 2023 LATEST UPDATE... Aviation .SHORT TERM...(This evening through Friday night) Issued at 230 PM EDT Thu Jun 22 2023 - Warm and windy for the rest of the day The large upper level low will continue to dominate the pattern today and through tomorrow. The strong easterly winds have allowed for low level clouds to form across the region. The strong easterly flow has allowed smoke from the Canadian wildfires to pool along and over the lakeshore. The models, specifically looking at the HRRR continue to show the smoke to move downwind from Ontario and settle over Lake Michigan with lots of smoke on the water. Winds will persist until after sunset. There should be some improvement overnight into tomorrow. - Possible Rain Tomorrow The weak band of showers that moved through eastern Michigan today had little to no precipitation in central Michigan. However it did moisten up the lower atmosphere. More bands of precipitation will cycle around the low tomorrow streaming in another round of clouds with higher PWAT values with it. Coinciding with it is slightly higher potential vort maxes which after 15Z Friday. This could allow for showers to move into the US 127 corridor late tomorrow morning through tomorrow afternoon. However any precipitation should measure less than a tenth of an inch. .LONG TERM...(Saturday through Thursday) Issued at 325 PM EDT Thu Jun 22 2023 Main forecast concern is for Sunday. Based on NBM CWASP guidance, Sunday afternoon looks at least marginally favorable for severe weather across our southern forecast area given expected good conditional instability /SBCAPE at or above 1000 J per kg/ and increased QG forcing and stronger mid level flow associated with an approaching upper low. In fact, SPC has already introduced a slight risk centered south of our area across the IN/KY region, Based on current CWASP guidance, however, would not be surprised to see the risk area expanded north into Lower MI as we get closer to the event. Ensembles for several runs now have been closely centered around a few tenths of an inch of precipitation (slightly greater south of I-96), lending good confidence to this aspect of the forecast. Precipitation chances continue beyond Sunday afternoon into Tuesday thanks to the aforementioned upper low, which will broaden and stall over the region. After this, predictability becomes far less certain with respect to precipitation. During the course of the work week temperatures should trend upwards towards climatology. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 752 PM EDT Thu Jun 22 2023 VFR conditions will prevail overnight although there could be some areas of MVFR fog near Lake Michigan. Rain showers will move north into south central Lower Michigan on Friday. Some areas of MVFR and patchy IFR is possible in the afternoon from LAN to JXN. && .MARINE... Issued at 245 PM EDT Thu Jun 22 2023 The lake breeze dominate flow will allow for northwesterly flow this afternoon and evening and could bring waves of 2 feet. The easterly flow will dominate through Friday so that will keep the wave heights to a minimum. Over the weekend the pattern starts to change. Waves could begin to increase into Sunday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SHORT TERM...Ceru LONG TERM...TJT AVIATION...Ostuno MARINE...Ceru
Area Forecast Discussion
National Weather Service North Platte NE
637 PM CDT Thu Jun 22 2023 ...Aviation discussion... .SYNOPSIS... Issued at 333 PM CDT Thu Jun 22 2023 Key Messages: - Thunderstorm potential continues Thursday afternoon and overnight into Friday with some strong to severe and heavy rain potential across southwest Nebraska. - More significant severe weather threat Friday afternoon and evening with Large hail, damaging winds, and heavy rainfall the main concerns though a tornado or two cannot be ruled out. - Training thunderstorms may lead to some flooding concerns Friday night into Saturday, particularly across much of north central Nebraska. - Quieter weather arrives for the latter half of the weekend with temperatures near to slightly below normal for late June. && .SHORT TERM...(This evening through Friday night) Issued at 333 PM CDT Thu Jun 22 2023 This Afternoon/Tonight...scattered to widespread thunderstorms are percolating across much of the local area. This is largely occurring along an area of weak low-level moisture advection and mid-level convergence. This activity is forming within an area of weak 0-6km bulk wind difference (BWD) of 20 knots or less and MLCAPE values of 1250-1750 j/kg. Given weak focus for lift, expecting coverage to be widely scattered away from the main area of low-level moisture pooling. With modest instability and shear, not expecting much in the way of a strong to severe thunderstorm threat and with loss of daytime heating, believe activity will quickly wane through the early evening. This thinking lines up well with latest HRRR and HREF thinking which shows quick waning of coverage by 02-03z. Attention then turns to thunderstorms working into southwest Nebraska off the higher terrain. Guidance is bullish on moist upslope flow leading to convection off the Front Range and Laramie Range further north by late afternoon. With mean wind flow generally southwest to northeast, expecting a largely west to east track of activity to move across northeast Colorado and approach portions of southwest Nebraska. With MLCAPE values in the 1000-1500 j/kg range and a modest uptick in deep layer shear at 25-30 knots 0-6km BWD, cannot rule out a stray strong to severe thunderstorm for areas south of Interstate 80 and west of Highway 25 late tonight. Believe storms will be weakening on approach however and any threat for severe hazards being fairly limited as a result. That said, cannot rule out an instance or two of severe hail up to 1" in diameter and 50 to 60 mph gusts. Of greater concern will be the threat for heavy rain with PWAT values exceeding 1.2" for much of the area and nearing the 99th percentile in NAEFS Climatology. Limiting confidence in any flooding potential will be limited coverage, expected weakening trend, and fairly progressive nature of the thunderstorms. Cannot rule out a few localized areas seeing 1-2" of rainfall, but given sparse coverage of this in areas that have seen recent heavy rains will forgo any flood watches at this time. Clouds and southerly winds will keep overnight lows mild, generally in the middle 50s to middle 60s or about 5 degrees above normal. Friday/Friday Night...the day of greatest concern regarding threat for strong to severe thunderstorms with some uncertainty with respect to timing and location of greatest concern. General southwesterly flow will persist locally with ridge axis situated immediately downstream the forecast area. A mid-level trough will track out of central California and lift north and east across the central to northern Rockies and onto the northern Plains by late in the day. Surface boundary stall invof the Pine Ridge will remain steady across the northwest zones. The approach of a stronger EML will lead to rapidly steepening mid-level lapse rates. With daytime highs climbing into the upper 70s to lower 80s, expecting a moderately unstable atmosphere to develop by mid-afternoon with MLCAPE values of 1500-2500 j/kg. An approaching mid-level speed max will lead to increasing deep layer shear to the tune of 30 to 40 knots of 0-6km BWD. This will be more than supportive of organized severe convection during the late afternoon and evening. Uncertainty resides with forcing and whether we see afternoon activity. For now, thinking the lack of any forcing early in the day will preclude anything more than an isolated thunderstorm. More widespread activity will arrive from the west late in the evening as the greatest mid-level height falls arrive in tandem with the orographically forced convection off the higher terrain. With shear vectors largely parallel to the frontal boundary in the area, expecting rapid upscale growth. Initially, discrete convection will be capable of large hail and damaging winds but cannot rule out a tornado or two across the eastern Panhandle and western Sandhills in an area of good low-level veering hodographs, primarily in the lowest 3km. Short-term CAMs indeed depict multiple UH swaths tracking out of the Nebraska Panhandle with isolated supercells. Forecast sounding analogs highlighting local significant hail events so this will bear watching. As storms grow upscale, expecting a transition to a mainly damaging wind threat as activity tracks into an environment characterized by delta theta-e values approaching negative 30 degC and DCAPE values of 1500-2000 j/kg and cold pools merge. Thinking the greatest potential for severe activity will remain north of the Interstate 80 corridor and as such have kept the greatest PoPs in these areas (> 55%). With a residual boundary stalled in the area and the potential for multiple rounds of convection in these areas, will need to be mindful of the threat for heavy rain and localized flooding. HREF mean values suggest a widespread area seeing 0.75"+ and ensemble max values show pockets of 2-4". Will hold off on any flood headlines for the time being and wait for increased confidence in placement of the greatest potential for repeated rounds of rain. The threat for heavy rain will last well into the early morning hours on Saturday before activity departs to the east and drier air rapidly works in from the west. All thunderstorms are expected to have exited the area by sunrise Saturday. .LONG TERM...(Saturday through Thursday) Issued at 333 PM CDT Thu Jun 22 2023 Saturday...expecting a largely dry day across western Nebraska as the aforementioned dry air spills out of the Great Basin. NAEFS guidance shows a quick flip from anomalously high PWAT values to anomalously low PWAT values by midday Saturday with mean PWATs of 0.50" for much of the area. Departing trough will lead to subsidence and mid-level height rises for the latter half of the day which will erode cloud cover and lead to moderating temperatures somewhat with daytime highs climbing into the middle 80s from southwest through north central Nebraska and the middle 70s for the far northwest. Westerly low level flow will increase behind a passing cool front and gusts will climb to around 25 to 35 mph for areas west of Highway 61 and closer to 20 to 25 mph elsewhere. Sunday and beyond...Quieter weather is expected for the start of next week as shortwave ridging arrives ahead of the main upper-level trough situated across the West Coast. Increasing mid-level heights along with modest moisture in place will keep precipitation chances at bay for Sunday into early Monday. By Monday, strong southerly low- level flow will again advect greater moisture into the region as a weak surface low takes shape across the central Rockies. This should lead to at least limited potential for rain and thunderstorms pushing off the High Plains beginning Monday with this potential repeating Tuesday. A stronger mid-level PV anomaly will track across the northern Plains by Wednesday and drag a cool front south into the area. This will lead to a day of higher precipitation chances locally with the frontal boundary though more precise timing remains somewhat in question. As we`re able to pin down timing, expect increasing PoPs for the Wednesday timeframe. Beyond that, southern Plains ridging will increase with a return to a more zonal pattern for the late week. This should help drive temperatures up slightly though the main core of heat should remain south of the area. With the general "Ring of Fire" pattern, expecting recurring chances for rain and thunderstorms but day to day predictability at this range is low confidence at best. Overall though, the pattern will favor a continuation of rain and thunderstorm chances and so the outlook remains fairly optimistic that we shouldn`t see the dog days of summer just yet and this jives with the latest CPC 8-14 day outlook favoring above normal precipitation and only a slight favor to above normal temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 636 PM CDT Thu Jun 22 2023 With widely scattered thunderstorms across central Nebraska this evening and old outflow boundaries from earlier convection still lingering, expect wind direction will be erratic at least through this evening until the boundary layer stabilizes with loss of diurnal heating. Convection should trend down at TAF sites this evening, and expect winds will settle generally at an easterly direction early tonight with speeds generally 10kt or less. Low stratus will bloom over the region toward daybreak with IFR/LIFR CIGs into early Friday morning. Guidance shows indications for late night convection to affect KVTN but confidence in this is not high so will monitor radar trends closely for later TAF issuances. Expect CIGs will gradually trend up and reach VFR by late Friday morning or early afternoon. The signal in guidance for convection tomorrow is mixed with a trend to hold off until after this valid period so will not use more than VCTS for Friday afternoon. && .LBF WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...NMJ SHORT TERM...NMJ LONG TERM...NMJ AVIATION...MBS
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 410 PM CDT Thu Jun 22 2023 Key Messages: - Rain chances are increasing this weekend but there is a lot of uncertainty as to timing. Widespread rainfall looks likely Friday night into Saturday day. - There is a Slight Risk for severe weather Saturday but will be dependent on the timing of the front. Very isolated convection is popping up on the radar generally in north central Nebraska this afternoon. It`s generally been initiating along a gradient of CAPE that extends into southeast South Dakota. Very little eastern motion is expected with that instability and convection. Areas along the Missouri River and points east will be dry tonight with POPs peaking at near 15% in the far western CWA this evening. Pleasant conditions are forecast for tonight with light southerly winds and lows in the mid-60s. Light POPs are warranted along the western edge of the CWA early Friday morning as a short-wave drives northeast into eastern South Dakota. Friday`s weather will feel similar to today`s with highs near 90 once again and continued light south winds. Afternoon showers and thunder are possible in northeastern Nebraska once again with a midlevel shortwave on the same southwest to northeast track as those that precede it. Severe weather isn`t anticipated with the lack of shear playing significant spoiler. PWAT values over the 90th percentile (1-2") remind us that an isolated heavy downpour is possible. Severe weather is looking increasingly possible with the development of an MCS working through the state of Nebraska on Friday night. CAMs and mid-range models are beginning to close in on unanimity in seeing the convection of the high terrain of WY/CO/western Nebraska coalesce into an MCS that finds its way into eastern Nebraska riding the nose of a 40 kt LLJ. Moisture transport would be particularly efficient. A greater number of ensemble members are coming up with this solution. This would bring a threat of damaging wind gusts to the area before sunrise Saturday morning. This solution, now becoming the predominant one, would leave severe convection less likely on Saturday with increased cloud cover, a deeper layer of convectively disturbed air at the surface and a higher LFC as a result. Saturday could spell trouble if that MCS doesn`t develop, turns further south (leaving our air mostly undisturbed), or fizzles earlier (leaving a boundary and mostly clear skies in the area). All modes of severe weather would be possible in this secondary solution. The RAP falls into this camp and would produce sfc CAPE of 3000 J/kg, deep shear of 30-50 knots, quick lapse rates, and hodographs resembling croquet hoops. Supercells could grow powerful quickly. The SPC rightly has an area of "hatched" hail along and east of the Missouri River suggesting the threat of hail over 2" (Day 3). If this solution were to verify, convective initiation may begin quickly near Omaha and/or the Missouri River after lunch on Saturday. Confidence in the ultimate outcome may not be particularly high until seeing Friday night`s radar returns. All solutions carry a threat of isolated flooding with marginal excessive rainfall outlooks painted across the area. .SUNDAY AND BEYOND... Regardless of how the severe weather evolves, drier air works in behind Saturday`s cold front on breezy northwesterly winds. Temps won`t be much cooler behind the front, with Sunday managing low to mid-80s, despite the mostly sunny skies. It will be even breezier. Mid-level ridging redevelops early next week with a shortwave riding the ridge and bringing chance POPs to the area by Tuesday evening. The ridge breaks down mid-week with an upper low sweeping across the Northern Plains and bringing another small opportunity for showers and thunder. This may keep Nebraska and Iowa from seeing the sweltering heat that will be developing across TX, OK, KS, and MO late next week. The WPC has highlighted these areas for high risk of excessive heat in "week two" with a slight chance forecast in portions of this area. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 604 PM CDT Thu Jun 22 2023 VFR conditions will prevail through the forecast period with a few clouds at FL060-070 and SCT-BKN clouds at FL200-250. Isolated showers are currently being observed over portions of southeast NE, but we don`t expect any of that activity to affect KLNK. A few models suggest that widely scattered showers and thunderstorms could develop over eastern NE Friday afternoon. Confidence in that occurrence at any of the terminal locations is currently too low to include in the forecast. Otherwise, southeast winds at less than 12 kt are expected to increase to 12-15 kt from the south late Friday morning into Friday afternoon. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Nicolaisen AVIATION...Mead
Area Forecast Discussion
National Weather Service Norman OK
1026 PM CDT Thu Jun 22 2023 ...New AVIATION... .SHORT TERM... (This evening through Friday) Issued at 230 PM CDT Thu Jun 22 2023 The primary near-term impact to our area will come from a long- lived, slow-moving complex of storms over the Oklahoma/Texas panhandle as of early afternoon. THese storms have formed along an outflow boundary left over from last night`s convection, which is now sharpening across our northwest Oklahoma zones from northern Ellis to southern Woods Counties. 850 mb flow is largely parallel to this boundary, which may encourage slow-moving, training convection, although current radar trends suggest that cold pool amalgamation will tend to drive that convection southward and potentially keep it in the Texas panhandle. Other than this complex, a low chance for storms exists across western north Texas. Severe weather is unlikely, but gusty winds and small hail are possible. Although humidity has been mercifully somewhat lower this afternoon, low 70s dewpoints are creeping back into southern Oklahoma and western north Texas. This will set the stage for an oppressive overnight. Given the amount of humidity, temperatures will be slow to fall and will likely not reach the dewpoint by daybreak, with widespread low 70s possible. Storm coverage tomorrow looks like it will be greater than today as an impulse brings 40-50 knots of 500 mb flow into our western zones. RAP forecast soundings show MLCAPE values reaching 4,500 J/kg with near-total erosion of the cap across western Oklahoma, in addition to 50 knots of effect bulk shear. This should be sufficient for severe weather, but several factors complicate this forecast. First of all, the forcing mechanism for storms is nebulous at most. THe dryline should remain back in the Caprock region, and southerly storm motions may spare our area from heavy weather through at least late evening again. Secondly, extremely high PWATs will reduce efficiency of hail growth and keep DCAPE values within manageable levels. Thus, we currently are messaging a marginal risk for severe weather tomorrow afternoon. Meister && .LONG TERM... (Friday night through next Wednesday) Issued at 230 PM CDT Thu Jun 22 2023 Storm chances will increase after sunset tomorrow night coincident with potential upscale growth of convection across the higher terrain. A few CAMs (notably, the ARW WRF and NSSL WRF) depict an organized MCS moving through the central portion of our area overnight. However, those particular members of the HREF have been "MCS-happy", so to speak, so that guidance is taken with at least a bit of a grain of salt. As the weekend kicks off, the main weather story will pivot back to heat. The ridge won`t go away - in fact, it is quite the feat to begin with that we have even had flow/storm chances given the strength of the ridge. As it builds back in, the risk of excessive heat will return immediately given the ongoing humid nature of the airmass. Saturday looks to be the most extreme day, and heat advisories/excessive heat warnings will likely be needed over a rather large swath of the area. Heat indices/WBGTR values will slowly decrease into early next week - not because we`re getting any cooler, but because humidity values will slowly drop off of the record-setting pace we`ve seen. Storm chances will also exist periodically throughout the weekend. Chances will be modulated by outflow boundaries from previous convection as well as the duration with which MCSs can survive off the high terrain; thus, predictability is low at this time. Storm chances will be lower next week as the core of the upper ridge moves overhead. Meister && .AVIATION... (06Z TAFS) Issued at 1024 PM CDT Thu Jun 22 2023 VFR conditions expected with mainly light southeast winds for a majority of the forecast period. Low confidence and model consistency in SHRA/TSRA across western Texas Panhandle making it terminals in the short term, but cannot rule it out either. Will confine mention of TSRA to late in the forecast when there is more agreement among guidance to bring storms in from west Texas toward and after 00Z tomorrow evening. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 72 88 72 97 / 70 20 20 0 Hobart OK 70 91 71 101 / 50 30 30 0 Wichita Falls TX 73 94 73 105 / 40 30 30 0 Gage OK 67 88 68 97 / 30 20 30 0 Ponca City OK 69 89 72 98 / 20 20 20 10 Durant OK 71 91 75 96 / 20 20 10 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...11