Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/02/21

See below for an aviation forecast discussion for the 00Z TAFs.

&& .SHORT TERM...(This Evening through Monday Night) Issued at 312 PM CDT Sun Aug 1 2021 Satellite, surface obs, along with the hrrr smoke forecast show our far eastern cwa being affected the most by surface smoke tonight. Several obs have come down to 5 miles late this afternoon. The hrrr surface smoke shows the smoke mainly affecting our far eastern cwa tonight as it mixes/thins out on Monday. The vertically integrated smoke and satellite also show smoke coming around the western upper level ridge through Monday night. The hrrr surface smoke does show little to no smoke on Monday across the cwa as it disperses. Therefore, have adjusted the surface weather grids and sky cover through the period. Otherwise, surface high pressure will build south across the region tonight into Monday. The winds will be mostly light and go from east northeast tonight to south into Monday. Highs on Monday will be a few degrees warmer than today in the 80s and lower 90s with lows tonight and Monday night ranging from the mid 50s to the lower 60s. Also, tonight through Monday night will be dry. .LONG TERM...(Tuesday through Sunday) Issued at 312 PM CDT Sun Aug 1 2021 An upper-level ridge will remain in place across the Rockies through much of the work-week, leading to predominantly dry conditions and above average temperatures across the forecast area (highs most likely in the 90s along and west of the James River Valley by the end of the week). A couple shortwaves from Friday through the weekend will flatten the ridge, usher in deeper moisture from the Gulf, and increase the chances for precipitation while maintaining above-average temperatures. Models are already in decent agreement about depicting a stronger shortwave through the Northern Plains by the end of the period. && .AVIATION...(For the 00Z TAFS through 00Z Monday Evening) Issued at 638 PM CDT Sun Aug 1 2021 Terminals KABR,KATY,KPIR,KMBG It appears there is a much better chance of seeing prevailing VFR conditions throughout the TAF valid period at all four terminals. The latest dispersion output supports some smoke (<3sm visby) maybe getting into the KATY terminal later tonight/early Monday morning for several hours. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Dorn SHORT TERM...Mohr LONG TERM...Lueck AVIATION...Dorn
Area Forecast Discussion
National Weather Service La Crosse WI
948 PM CDT Sun Aug 1 2021 .SHORT TERM...(This evening through Monday) Issued at 248 PM CDT Sun Aug 1 2021 We continue to see the elevated and near surface smoke/haze get pushed out of the area with high pressure building in. However, the reprieve from the smoke/haze may not last long with GOES-16 satellite showing more spreading southward to the international border. The HRRR seems to be handling trends well and would support a return of the smoke on Monday, though likely not as prolific and mostly remaining elevated with limited surface impacts. Otherwise, very pleasant/comfortable summer weather remains on tap compliments of Canadian high pressure. Generally 50s for lows with 40s possible in cold drainage areas, and 70s for highs Monday. There is a small chance for a few showers Monday afternoon, with some glancing lift attendant to a passing shortwave to our east. For now have confined these PoPs to our far north where model soundings show a bit deeper mid level moisture and some weak instability with SBCAPEs of 200-600 j/kg. .LONG TERM...(Monday night through Sunday) Issued at 248 PM CDT Sun Aug 1 2021 A few showers can`t be ruled out once again Tuesday afternoon, especially in our far north/east service area with some signal for a weak backdoor front nearby and glancing shortwave energy. Overall though predominantly dry conditions into midweek with heights aloft increasing atop a gradually retreating surface high. A developing light southerly wind will foster temperatures moderating closer to seasonal norms on Wednesday. The latter half of next week into the weekend looks to turn more unsettled/active as the flow aloft turns semi-zonal and strengthens. A predominantly SSW low to mid level flow will usher in warmer air with temperatures near to a bit above normal. Moisture will also gradually increase, and lead to periodic shower and storm chances with embedded shortwaves in the meridional flow. && .AVIATION...(For the 06Z TAFS through 06Z Monday evening) Issued at 946 PM CDT Sun Aug 1 2021 High pressure will provide mainly VFR conditions at the TAF sites. The only concern overnight will be some valley fog and whether it will affect KLSE or not. At this time, there is still a 12F spread in the temperature and dew point, so just went with a BCFG toward sunrise. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...McClure LONG TERM...McClure AVIATION...Boyne
Area Forecast Discussion
National Weather Service Denver/Boulder CO
905 PM MDT Sun Aug 1 2021 .UPDATE... Issued at 829 PM MDT Sun Aug 1 2021 The forecast remains on track this evening with only a couple showers in the mountains. The latest run of the HRRR smoke model keeps smoke across the I-25 corridor and plains through tomorrow so smoke will be kept in the forecast. && .SHORT TERM...(This evening through Monday) Issued at 250 PM MDT Sun Aug 1 2021 Current satellite and radar shows the bulk of convection staying well to our west over western Colorado, under the deeper moisture plume. We don`t see this plume shifting much through the evening, as low levels are still drying slightly and only the upper levels are attempting to moisten. We`ve trimmed back PoPs a little more for the high country, but isolated to scattered convection is still possible along/west of the Continental Divide. Temperatures will be relatively cool and slightly below normal for tonight. On Monday, we do see the deep monsoonal moisture plume shifting ever so slightly and slowly eastward. This should result in an uptick of convective coverage and intensity across our mountain areas, and with that, an increased risk of flash flooding to burn scars mainly west of the Front Range. The deeper moisture is expected to arrive slowly given the amplitude of the ridge and slow advection of monsoonal moisture ahead of the upper level disturbance moving across the Great Basin. However, by late in the afternoon and evening we should start to see a few storms work east down the Front Range. Most of those may end up being outflow dominated and weakening, reducing the threat of heavy rainfall. Most of the plains east of I-25 should stay dry through the afternoon. Temperatures will continue to warm, with mid to upper 80s for highs across the plains. .LONG TERM...(Monday night through Sunday) Issued at 212 PM MDT Sun Aug 1 2021 We should see at least a few showers continue through the early overnight hours tomorrow night as our moisture plume slowly drifts to the east. Instability should decrease fairly quickly after sunset as we lose daytime heating, but there could be a continued heavy rain threat through the evening. After midnight, most of our activity will die off, but our specific humidities are likely to moisten. Tuesday is shaping up to be a bit wetter than Monday, with better moisture across most of our CWA. Model soundings over the high country show more than adequate instability in addition to PWATs approaching an inch. Forecast guidance is still somewhat inconsistent with the overall setup, with the GFS and GEFS are a bit drier/stable over the high terrain while the Euro ensemble suggesting high probabilities of surface CAPE > 500 J/kg. Have opted towards the Euro and wetter solutions for now, but confidence in the overall setup is still relatively low. However, if guidance continues to advertise a good parameter space for heavy rain, and additional Flash Flood Watches could be needed for the high terrain. Stay tuned. Tuesday night into Wednesday could see some activity drift off into the plains as moisture continues to slide to the south and east. Have increased PoPs a little over the plains compared to NBM but overall precip potential is fairly low. Model soundings show at least a weak cap Tuesday evening, but we could transition to a light rainfall event into Wednesday morning if the Euro solution is reasonable. Will have to watch trends there as recent runs have been more optimistic at getting measurable precip into the metro. Beyond Wednesday, the pattern quiets down a little bit with most of our moisture shunted out of the region. Warmer and drier weather looks likely Thursday and Friday, with temperatures warming back into the 90s. Another monsoon push of moisture is possible by next weekend, but for now will maintain just chances of afternoon storms across the high country. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 829 PM MDT Sun Aug 1 2021 ILS landing conditions should persist for another hour or two with visibility improving slightly as the evening progresses. By daybreak, visibilities will decrease again so ILS landings can be expected. We don`t expected any thunderstorms through most of Monday, as we`ll be too stable. There`s just a slight chance of a storm toward 00Z Tuesday. && .HYDROLOGY... Issued at 250 PM MDT Sun Aug 1 2021 It appears most of the convection through this evening will stay west of the burn areas. There is just a limited threat for flash flooding west of the Continental Divide (East Troublesome and Williams Fork burn areas). There is still a relatively high amount of moisture there so if a storm can develop, a quick one half inch of rain is possible. Deeper moisture gradually returns to the forecast area Monday, although the best arrives late in the afternoon or evening hours. Right now, it still looks like areas along and west of the Front Range will have the main threat of heavier rainfall. Precipitable water and 700-500 mb specific humidity should be sufficient for decent precipitation efficiency, and rainfall rates up to 1 inch in 40 minutes. However, we are uncertain regarding destabilization and the exact timing of arrival of the better moisture as the upper level disturbance over the Great Basin will be slow to move into the upper level ridge axis. We`ve issued a Flash Flood Watch for the burn areas mainly along and west of the Front Range, although it`s not impossible the threat could shift into the lower elevations of the Cameron Peak burn toward late afternoon or evening. The Watch could be expanded later if moisture arrives faster than currently expected. Flash flooding concerns will continue on Tuesday. The moisture plume should be over our forecast area, with PWATs near 150% of normal with very weak steering flow. It looks like there`s a little bit more forcing over the region during the afternoon, and thus there should be more widespread coverage across the high country during the day. With instability increasing yet again, in combination with the aforementioned weak steering flow, slow moving thunderstorms would be likely. We`re still far enough out that this could change, but it is certainly possible that another Flash Flood Watch could be needed for the high terrain. Some of the rainfall could drift into the I-25 corridor, but there is less confidence in that happening. && .BOU WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from Monday afternoon through Monday evening for COZ032>034. && $$ UPDATE...Danielson SHORT TERM...Barjenbruch LONG TERM...Hiris AVIATION...Danielson HYDROLOGY...Barjenbruch/Hiris
Area Forecast Discussion
National Weather Service Charleston SC
1023 PM EDT Sun Aug 1 2021 .SYNOPSIS... A stationary front will maintained unsettled weather including the chance for heavy rainfall across the area through the upcoming week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... It`s taken awhile, but convection has finally arrived along a southward progressing outflow boundary and the collision of the earlier sea breeze and some activity moving in from the west. With forcing from a short wave aloft, the HRRR and the HREF indicate clusters or a broken band of showers and thunderstorms will impact mainly the Charleston quad-county region through 1 or 2 AM, before pulling offshore. We will show 40-50% chances this areas where the higher MLCAPE of 1500 to 2000 J/kg exists. PoPs elsewhere will be held to 20-0% where instability is less. DCAPE as high as 1000-1200 J/kg will still support the possibility of strong or perhaps marginally severe winds over the 4 counties surrounding Charleston County. We maintained mention of this in the Hazardous Weather Outlook. Temps in many places are running a bit lower than this time last night. Since dew points are also lower than 24 hours ago, min temps tonight are forecast a tad lower than last night. We are expecting mid or upper 70s across the entire region. The exceptions might be coastal Charleston and coastal Colleton if convection fades before there. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... This period will feature a change to cooler temperatures and a wet pattern including the potential for heavy rainfall and flooding. Monday: A surface cold front will stall over or just north of the region, while an upper level trough will amplify over the eastern CONUS. Guidance indicates that best moisture featuring PWAT values around 2 inches should be temporarily pushed into southern counties. Given this scenario, isolated/scattered showers and thunderstorms should hold off until afternoon across northern/inland counties. Across the south, showers/thunderstorms will develop earlier, and by mid to late afternoon expanding coverage justifies at least likely PoPs. MLCape values as high as 2500-3500 j/kg could support a localized threat for brief/damaging wind gusts across southern counties Monday afternoon. Otherwise, Monday will spend the end to the recent excessive heat regime. Across southern counties, heat index values could top out in the 100-105F, while maximum heat index values 95-100F will be common elsewhere. Give these expectations, additional Heat Advisories are not expected. Monday night: We will transition to more widespread showers/thunderstorms and an increasing threat for locally excessive rainfall/flooding. A unusual baroclinic regime will develop in the vicinity of the quasi-stationary front. Also, as the anomalous eastern CONUS longwave trough amplifies, a shortwave trough will eject NE across the region. Meanwhile, low-mid level moisture transport will intensify and will push a plume of PWAT values 2.2-2.3 inches across the forecast area. categorical PoPs offered by guidance appear reasonable, and repeating periods of heavy rainfall could produce localized flooding. Sunday 12z HREF guidance depicts non-zero probabilities of 12 hour precipitation exceeding 5 inches across a wide swath of the forecast area, including pockets of 20-60 percent probs near the coast. Tuesday through Wednesday: A persistent pattern with an anomalously deep eastern CONUS upper trough, shortwave troughs/associated forcing for ascent ejecting from this feature across our area, an unseasonably strong, active baroclinic zone, deep-layered moisture advection within the plume of PWAT values mainly exceeding 2 inches will combine to support episodes of widespread showers/thunderstorms and a threat for locally excessive rainfall/flooding. Latest forecasts include mainly categorical PoPs through this period, but in reality periods with widespread precipitation could be punctuated by periods of lesser coverage. This type of regime raises uncertainty regarding specific timing, coverage/location and rates/amounts of heavy rainfall. In general, over time total rainfall accumulations should increase in amount and coverage, and this will in turn raise the probability for significant flooding during subsequent episodes of heavy rain. Otherwise, expect below-normal temperatures through midweek. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... The overall complex and unusual scenario at the surface and aloft which sets up through midweek will persist through late week and perhaps even into next weekend. Overall, above-normal precipitation, the potential for locally heavy rainfall and flooding, and below normal temperatures will continue. While the greatest coverage and intensity of precipitation seems most likely during times of maximum heating during each afternoon/evening, precise timing and impact of heavy rain events remains elusive. In general, the overall threat for flooding should increase with time due to the persistence of this unseasonable scenario. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... There continues to be indications that the convection upstream will develop into a broken band of SHRA/TSRA, and impacting the KCHS and KJZI terminals from about 03-06Z. This is also somewhat consistent with the previous forecast. Convection near KSAV looks to stay too isolated in coverage to show anything more than VCTS from 04-06Z. Direct impacts on any terminal, especially KCHS and KJZI will result in flight restrictions and potentially gusty winds. Monday morning and early afternoon will essentially be void of convection, before coverage increases during the mid afternoon and beyond. This occurs in response to a nearby cold front and an approaching upper trough. However, since any SHRA/TSRA will occur so late in the latest 00Z TAF period, we have opted not to include at this time. Be assured that any direct impacts though will cause flight restrictions. Latest TAF issuances will fine tune the situation. Extended Aviation Outlook: Periods of flight restrictions are certain this week, especially in showers/thunderstorms. && .MARINE... Overnight: Southwest winds across the SC waters will continue to gusts to around 25 kts through 1-2 AM, resulting in a continuation of the ongoing Small Craft Advisories for AMZ350 and AMZ352. A band of strong thunderstorms will push off the coast and impact mainly the South Carolina Atlantic waters and Charleston Harbor from 12 AM to 2 or 3 AM. Special Marine Warnings could be required for winds in excess of 34 kt. In the wake of the thunderstorms, winds are expected to shift from the WSW, with speeds of 15 kt gusting to 20 kts. Seas are expected to range between 2-4 ft. Expect hazardous marine conditions within/near thunderstorms through this week. Outside thunderstorms, southwest winds could average 15- 20 knots at times, and seas should average 2-4 feet, perhaps as high as 5 feet beyond 20 nm, through late week. Occasional Small Craft Advisory gusts cannot be ruled out. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...Small Craft Advisory until 2 AM EDT Monday for AMZ350-352. && $$ NEAR TERM... SHORT TERM...SPR LONG TERM...SPR AVIATION... MARINE...
Area Forecast Discussion
National Weather Service Des Moines IA
635 PM CDT Sun Aug 1 2021 .SHORT TERM.../Tonight through Monday Night/ Issued at 229 PM CDT Sun Aug 1 2021 Confidence: High High amplitude flow continues to intensify over the upper Great Lakes early today with large gyre over eastern Canada bringing nearly due north winds into Iowa and the Great Lakes states. A weak cool front at 12z bisects Iowa from northwest to southeast while another weaker boundary is located over northern MN/WI vicinity. Aloft the Iowa boundary`s H850 reflection is easily seen on subjective hand analysis. The main area of moisture aloft is currently south of a frontal boundary that stretches from New York State through the lower Ohio River Valley southwest into the Texas Panhandle northwest toward the Pacific Northwest. South of the boundary H850 dewpoints are in the 10 to 15C range with the highest moisture confined to the southeast for the time being. An expansive ridge of high pressure continues over the western states where H850 temperatures are now in a range of 15 to 25C while the cooler intrusion of air into Iowa and the Great Lakes now ranges from 10 to 14C this morning. Iowa continues to see forest fire smoke drifting south southwest this morning and covering most of the state north into Minnesota. Air quality concerns have returned for much of the region through Monday. Tonight will remain quiet with a continuation of northerly flow. Despite the smoky skies present, with the cooler H850 airmass intruding south now, our overnight lows will drop to into the lower 50s northwest to the upper 50s south. Though about 7 degrees cooler than normals, we will still be shy of any records by about another 7 degrees tonight. The expansive area of cooler high pressure will drop southeast tonight into Monday and keep the region quiet with light winds and very pleasant temperatures. Similar to today, highs Monday will only reach the upper 70s to around 80 as some smoke remains across the region. Little change is expected Monday night as the high pulls east and H850 temperatures begin to recover slowly into Tuesday morning. Lows will be similar to tonight, but a degree or so warmer for most locations. .LONG TERM.../Tuesday through Sunday/ Issued at 229 PM CDT Sun Aug 1 2021 Confidence: Medium to High Overall, the extended forecast remains generally quiet through at least Wednesday. Tuesday the high will continue to edge east into the Ohio River Valley while a weak trough begins to take shape over the Northern Plains. In response to the increasing warm air advection, a warm front is anticipated to form from western Minnesota to northeast Wisconsin. Increasing instability may lead to some clouds and showers and thunderstorms; mainly over MN and Wisconsin with some mid-level clouds over the north/northeast Tuesday afternoon. Otherwise, highs Tuesday will begin to warm faster northwest as H850 temperatures increase over the area and reach the mid-upper teens northwest by Tuesday. By late Wednesday, the trough/low over the Northern Plains will begin to drift southeast across MN as the low tracks northeast into Canada. Temperatures will again be warmer northwest with afternoon highs in the mid 80s and another dry day can be expected. The weak boundary is expected to drift southeast Thursday and interact with a weak wave. This should bring a chance of showers and thunderstorms across Iowa during the day. Highs Thursday will change little from Wednesday. By the end of the week into the weekend, energy currently off the coast of British Columbia will shed a short wave east into the Northern Plains. With increasing westerlies aloft, our temperatures will begin to see a bump up as hotter air west begins to migrate east with time. H850 temperatures Friday should be in the upper teens with readings on Saturday 21-24C by days end. While the GFS forecasts H850 temperatures nearing 23-26C by 00z Sunday and crashes temperatures into Sunday with a cold front that may not have enough upper level support to dive south through Iowa; the more modest and consistent Euro is tracking at 22-25C through 00z Sunday and remains about the same on Sunday. Deferring to the more consistent Euro suggests that highs Saturday should reach the lower 90s with highs on Sunday the lower to mid 90s west. Both medium range models suggest a wave and push of thetae advection overnight Sat night into Sunday morning, resulting in chances for storms. Though instability parameters are sufficient for some stronger storms, at this time the better forcing and bulk shear is forecast into Minnesota/Wisconsin and mainly northeast of our area, though we have included some chance PoP northeast. Though the GFS again appears too fast again next weekend, both medium range models suggest a front near the region early into the following week and a potential for more storms. && .AVIATION.../For the 00Z TAFS through 00Z Monday evening/ Issued at 632 PM CDT Sun Aug 1 2021 Confidence in VFR conditions has increased with much of the near surface smoke affecting visibilities now south and west of TAF sites and expected to remain so through the period based on HRRR smoke trends. Although there may be some VFR smoke aloft central and west through midday Monday, mainly expect nothing more than few-sct high based diurnal cumulus with light and variable winds. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && $$ SHORT TERM...REV LONG TERM...REV AVIATION...Small
National Weather Service Sioux Falls SD
1038 PM CDT Sun Aug 1 2021 .SHORT TERM...(This Evening through Monday) Issued at 234 PM CDT Sun Aug 1 2021 The primary concern in the short term is smoke and air quality across the area. A ridge of high pressure will move over the area overnight and then slowly move to the east through the day on Monday. HRRR Smoke model shows near surface smoke moving into southwestern Minnesota later this evening and then slowly spreading west overnight. In addition, the nocturnal inversion may also allow smoke to concentrate near the surface overnight producing unhealthy air quality - especially along and east of I-29. Wind will remain light on Monday although strong summer sun should allow for a deepening boundary layer which is expected to improve air quality to some extent through the late morning and afternoon. No precipitation is expected through Monday. Clear skies and light winds will allow for good radiational cooling tonight. Lows overnight will be in the 50s. Highs on Monday will be in the 80s. .LONG TERM...(Monday Night through Sunday) Issued at 234 PM CDT Sun Aug 1 2021 For the long-term a warming trend is expected through the week and into next weekend. Dry weather is expected through Tuesday night across the area as northwest flow aloft continues. As the ridge moves to the east, southerly flow will increase aloft first and reach the surface during the day on Tuesday. There is uncertainty if smoke will again be an issue Monday night into Tuesday morning before southerly winds increase. On the one hand a strong nocturnal inversion will again develop helping to concentrate any smoke near the surface. However, with light winds, there should be less smoke advecting southward. And mixing Monday afternoon will help to remove some smoke from the boundary. At this time did not include smoke in the forecast for Monday night or Tuesday but for those who are negatively impacted by smoke, check later forecasts to see how air quality will evolve. Otherwise, mostly clear or sunny skies are expected. With strengthening southwest winds above the surface, there may be stronger winds northeast of the Buffalo Ridge late Monday night which will help keep temperatures in the lower 60s. Otherwise, lows will range from the mid 50s in northwest Iowa to around 60 in south central South Dakota. On Tuesday, highs will range from the mid 80s east of I-29 to around 90 west of the James River. An upper level wave will approach the region on Wednesday. A surface trough is expected to extend across central South Dakota. While winds will turn southerly ahead of the wave, moisture is very limited with dew points likely to still be in the 50s by late afternoon. 700-500 mb lapse rates are also only 5.5-6.5 C/km so instability is also limited. This results in MLCAPEs less than 1000 J/kg. However, it is saturated above 700 mb so the question will be if the forcing for ascent will last long enough for the lower atmosphere to become saturated and rain to reach the ground. There is a stronger signal from ensemble forecasts for rain Wednesday into Wednesday night. While guidance PoPs remain around 20 percent, confidence is slowly growing for at least scattered showers Wednesday afternoon and night. A low amplitude ridge builds in the area for the end of the week and the weekend. There remains uncertainty on the timing and location of a leading wave moving into the area Saturday. Some ensemble members keep this wave closer to the Rockies while others take the energy closer to the Canadian border and few bring this wave across South Dakota. With persistent southerly flow moisture will be increasing but so will mid level temperatures with 700 mb temperature above the 90th percentile in the ECMWF ensemble and mean GFS 700 mb temperature greater than 12 C. This may result in a strong enough cap to limit or even completely suppress any convection this weekend. If convection does not develop through Sunday it could be hot this weekend. The potential exists that some places west of I-29 could rise above 100 degrees with most other areas in the mid to upper 90s. Should convection develop, then various outflows and clouds may "cool" temperature closer to 90 for highs. Bottom line is that any precipitation remains very uncertain through the next 7 days and another round of heat is likely by later this week. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1036 PM CDT Sun Aug 1 2021 Overnight, expect near surface smoke to reduce vsby down to MVFR along and east of the Interstate 29 corridor, including near FSD and SUX, as sfc high pressure builds through. Further west, should see mainly VFR conditions with weaker southerly flow and patchy smoke possible. Expect vsby improve some at the sfc through the morning as mixing increases winds but will still see smoke stream through aloft through the day. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...Schumacher LONG TERM...Schumacher AVIATION...BP
National Weather Service Hastings NE
646 PM CDT Sun Aug 1 2021 ...AVIATION UPDATE... .DISCUSSION...(This evening through Sunday) Issued at 250 PM CDT Sun Aug 1 2021 Forecast concerns include smoke/haze at least in the near term, and then warming temperatures for the weekend. Overall deterministic and ensemble models are in decent agreement with the upper pattern for the next week. Will lean more on a blend of deterministic models until the weekend, and then use a blend of ensembles as deterministic models show more divergence in solutions. HRRR smoke runs indicate that we could have a minor increase in smoke coming tonight, but overall this should back off for Monday, but smoke particulates will be stubbornly present to include haze for the forecast heading into Monday/Monday evening. Until we can get a shift of upper flow away from the north or northwest, this could become a recurring feature for the next several days, unless fires substantially quell. Upper pattern reveals a ridge over the intermountain west that is de- amplifying over time as a number of waves over the northern tier help break it down. At the surface, a surface ridge will cross the central Plains tonight with return flow ensuing for the week. This will allow temperatures and dew points to slowly increase over time, although slowly since the affects of the upper ridge are diminishing over our area. By late in the work week, a trough will clear the Plains and allow a temporary ridging to occur that will stem from the subtropical ridge behind the shortwave trough and should help boost temperatures into the 90s for highs. We have already been trending warmer for the weekend and this seems like a prudent direction. Although the forecast is mostly dry, there is a non-zero chance of rain Wednesday night as a shortwave trough is still forecast by deterministic models to come through the area within north flow and there is potential for enough deep layer moisture to at least produce isolated rainfall, especially north of the tri- cities. This will need to be monitored for trends in future numerical model runs. Kept trend of combining NBM and CONSALL for highs on the weekend to help boost temps up a couple degrees into the mid 90s. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Tuesday) Issued at 645 PM CDT Sun Aug 1 2021 Significant weather: Minor visibility reductions due to smoke. Tonight: Main issue will be continued haze from ongoing smoke. VSBYs across the local area and upstream are better than 24hrs ago, so think we`ll be primarily high end MVFR or VFR. Little to no cld cover expected. NE wind will go lgt and vrbl around sunset. Confidence: High. Monday: Latest HRRR smoke runs suggest even more incremental improvement to at least near-sfc smoke concentrations, so have primarily VFR VSBYs for the daytime hrs. Will continue mention of haze, though as smoke unlikely to completely vanish. Again, little to no cloud cover. Lgt and vrbl winds in the morning will become S-SE by midday, but only around 5-7kt. Confidence: High. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ DISCUSSION...Heinlein AVIATION...Thies
Area Forecast Discussion
National Weather Service Green Bay WI
701 PM CDT Sun Aug 1 2021 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Monday Issued at 257 PM CDT Sun Aug 1 2021 The main forecast issue focuses on Monday and whether any showers or thunderstorms can develop in a weakly unstable, weakly forced environment. The 19Z MSAS surface analysis showed a weak area of low pressure over the eastern Great Lakes, a cold front stretched out from the OH Valley to the central Plains and high pressure sinking south into northern sections of ND. Visible satellite imagery indicated plenty of cumulus clouds across the Great Lakes with thicker clouds over the MN Arrowhead/northern WI/western Upper MI. Radar had picked up on a few sprinkles over Upper MI at times, but not overly impressive returns. Any lingering cumulus clouds will dissipate early this evening as daytime heating wanes and drier air from the high pressure settles over the region. The high pressure will reside over the Midwest/ western Great Lakes tonight with mostly clear skies for most of the night. A weak surface trough and weak mid-level shortwave trough are forecast to swing into the northern Great Lakes toward daybreak and may bring some increase in clouds into northern WI. Min temperatures to range from the middle 40s to around 50 degrees north, to the middle 50s east-central WI. This high pressure settles into southern sections of the Great Lakes region on Monday, allowing winds to become west-southwest and bring a slight uptick in WAA. Meanwhile, the surface trough continues to track east across the northern Great Lakes and the shortwave trough digs into the middle of the Great Lakes. Instability is weak (SBCAPES < 500 J/KG), shear is weak (20-25 kts), and lift is negligible. There may be just enough forcing to squeeze out a few showers in the afternoon, but the vast majority of the forecast area should be dry on Monday. Max temperatures for Monday to mainly be in the middle to upper 70s. .LONG TERM...Monday Night Through Sunday Issued at 257 PM CDT Sun Aug 1 2021 Fairly quiet weather expected through at least mid week, then increasing humidity and unsettled weather toward the end of the week into the weekend. Monday night: A dry surface ridge is will shift slowly southeast of the area through this time period, bringing little to no precipitation. The one exception could be early Monday evening as a shortwave shifts to the southeast of the area. Instability is expected to be around 500 J/kg through early evening; however, the instability will quickly diminish toward sunset. Not expecting anything severe, but an isolated thunderstorm may linger into the early evening hours. Otherwise, temperatures are expected to be near normal. Overnight lows will be in the upper 40s. Tuesday through Wednesday: Models are hinting at a surface boundary sinking southward into the area Tuesday into Tuesday night (although with differing timing/placement), which may lead to some afternoon showers and thunderstorms. This would mainly be during peak heating into the early evening hours before diminishing after sunset. In fact, models are painting out around 1000-1500 J/kg of MUCAPE, but shear values are only around 15-20 kts. This would allow for strong storms, but a relatively low threat of severe from pulse-type storms. Behind the front, drier air is expected to arrive, bringing fairly quiet conditions for Wednesday. High temperatures will warm into the low to mid 80s with overnight lows in the 50s. Rest of the extended: Model solutions differ on exact timing and placement of features beyond Wednesday; however, there is some agreement that a shortwave will pass through the area Thursday afternoon into Thursday night and yet another larger scale system approaching the area toward next weekend(Saturday. Instability will steadily increase through this time period as dewpoints and temperatures increase across the area. This will lead to a more unsettled/active pattern for northeast Wisconsin with increasing chances for showers and thunderstorms. Severe weather may be possible from time to time, but it is too early to pin down the details. && .AVIATION...for 00Z TAF Issuance Issued at 658 PM CDT Sun Aug 1 2021 Generally quiet weather with mainly VFR conditions is expected throughout the TAF period. HRRR smoke guidance suggests minimal impact at the surface tonight into mid-day Monday, with perhaps some vsby restriction across the north returning tomorrow afternoon. Convective cloudiness is likely to develop during the late morning tomorrow, but bases should be abv 3K ft. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....Kallas LONG TERM......Cooley AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
724 PM EDT Sun Aug 1 2021 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 258 PM EDT Sun Aug 1 2021 - Quiet Weather this Week && .DISCUSSION...(This evening through next Sunday) Issued at 258 PM EDT Sun Aug 1 2021 Upper troughing will bring several days of cooler than normal temperatures before temperatures warm up by next weekend as heights begin to rise. Only slight chance of showers on Tuesday across the northeast zones as a shortwave trough moves through with little moisture to work with. Warm advection pattern and return flow moisture results in increasing chances of showers and thunderstorms by the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 724 PM EDT Sun Aug 1 2021 The scattered showers that have been around late this afternoon into early this evening are dissipating and should be totally gone by 02z. Based on the the HRRR Smoke model I have added FU (smoke) to most of the TAF forecasts during the sunrise hours of Monday. There may be some light fog at that time too. Winds will become light by midnight. On Monday another shortwave comes through the area from the north. This will result in the risk of isolated showers during the afternoon. I did not put this in the TAF forecasts as the risk is rather low and even if it happened, likely it would have little impact on the Cigs/Vis. Winds will be northwest 5 to 10 knots during the day light hours. && .MARINE... Issued at 258 PM EDT Sun Aug 1 2021 No changes to the forecast with winds and waves expected to decrease overnight followed by several days of relatively light winds and waves and good boating/swimming conditions. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Beach Hazards Statement until 5 AM EDT Monday for MIZ037-043-050- 056-064-071. LM...Small Craft Advisory until 5 AM EDT Monday for LMZ844>849. && $$ SYNOPSIS...Ostuno DISCUSSION...Ostuno AVIATION...WDM MARINE...Ostuno
Area Forecast Discussion
National Weather Service Wichita KS
645 PM CDT Sun Aug 1 2021 .SHORT TERM...(This evening through Wednesday night) Issued at 153 PM CDT Sun Aug 1 2021 BOTTOM LINE UP FRONT: Below normal temperatures and mostly dry conditions are expected to start the work week, and will be accompanied by areas of smoke/haze. Temperatures and humidity will then gradually increase from mid-week on. Thunderstorms are possible WED/THU and again towards the weekend. DISCUSSION Latest surface analysis, early this afternoon, reveals a frontal boundary continuing to sag south through the Southern Plains, putting the Central Plains in a more stable, drier, northerly flow. That said, lingering low to mid-level moisture and instability may still allow a few diurnally-driven showers/storms this afternoon near the KS/OK border ahead of a secondary push of drier/more stable air. The more substantial push of drier/more stable air will settle in over the next couple of days, and should keep a lid on convection through at least Tuesday. With northerly mid/upper flow continuing through mid- week, smoke will continue to advect into the region from fires in Canada. HRRR smoke guidance suggests this smoke layer may tend to become more elevated by Monday, leading to hazy looking skies, but with visibility and air quality not quite as bad as the next 12 hours. Of note, most observation sites across the Central Plains are showing reduced visibility due to the smoke, so it`s an impressively widespread area of smoke our region is dealing with, and may not mix out/become elevated as fast. Adding to the reduced visibility will be the potential for shallow low-level moisture/small T/Td depressions that may lead to some shallow fog each morning. By mid-week, a s/w is forecast to move out of the Central Rockies and into the Central Plains as WRN U.S. ridging breaks down some. If sufficient moistening occurs ahead of this wave, we could be looking at a risk for isolated to scattered convection. However, from a probabilistic standpoint, the majority of ensemble members from the GFS/EC/CMC are dry, which gives lower confidence in seeing a meaningful risk of precip locally. We`ll continue to see how this wave trends in future model runs, though. If it comes out a bit deeper, there could be a better return of moisture and an increased risk of precip. Temps through mid-week will be noticeably lower than what we have seen over the past week, possibly kept even lower due to elevated smoke. A gradual moderation is expected by mid-week, but at this time it appears unlikely that we will see a significant rise in temps or humidity. Martin .LONG TERM...(Thursday through Sunday) Issued at 153 PM CDT Sun Aug 1 2021 In the wake of the mid-week wave, upper level ridging may briefly build in Thursday before getting flattened by the end of the week. Ultimately this should set up more of a zonal flow across the Central Plains through next weekend. Increasing southerly low-mid level flow combined with some modest downsloping should lead to a more substantial warmup once again across the area. The southerly flow will help bring increasing moisture/humidity as well. Warming low- mid level temps should keep a pretty strong cap in place during the day, keeping the risk of storms low. Towards the weekend, some model guidance suggest a frontal boundary may attempt to move through the area with at least a modest increase in the risk of storms. If guidance is too quick to move that boundary through, though, then we`ll probably be looking at a continued period of dry conditions. Martin && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 633 PM CDT Sun Aug 1 2021 For the most part no significant weather is expected through this TAF period. Unfortunately, smoke from the fires along the west coast will be moving into the region during the evening and overnight. The atmospheric set up is such that much of this smoke is expected to reach the ground and obscure some of the visibilities toward 12Z and into the later half of the TAF. KCNU is the most likely terminal to have issues and could see near IFR visibility during after 17Z. KICT and KSLN may also have some intermittent MVFR visibilities after 12Z. KHUT is expected to be on the western fringe of the smoke this TAF period with KRSL and KGBD likely to remain clear. Metzger && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 62 86 62 87 / 0 0 0 0 Hutchinson 59 88 61 88 / 0 0 0 0 Newton 60 85 61 86 / 0 0 0 0 ElDorado 60 84 60 84 / 0 0 0 0 Winfield-KWLD 61 85 61 86 / 0 0 0 0 Russell 59 89 61 91 / 0 0 0 0 Great Bend 59 88 60 89 / 0 0 0 0 Salina 59 88 61 90 / 0 0 0 0 McPherson 59 87 61 88 / 0 0 0 0 Coffeyville 63 84 61 85 / 0 0 0 0 Chanute 61 83 60 83 / 0 0 0 0 Iola 61 83 60 82 / 0 0 0 0 Parsons-KPPF 62 84 60 84 / 0 0 0 0 && .ICT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...RM LONG TERM...RM AVIATION...ELM
Area Forecast Discussion
National Weather Service Indianapolis IN
1148 PM EDT Sun Aug 1 2021 ...Updated Aviation Discussion... .Forecast Update... Issued at 959 PM EDT Sun Aug 1 2021 Temperatures are in the 60s with dewpoints in the upper 40s to lower 60s and northerly winds around 4 to 12 mph. High pressure is building in from the northwest and satellite loop shows clear skies. Forecast is generally on track and no significant adjustments made, although have less confidence in the development of patchy fog with the pressure gradient across the area not relaxing as much as earlier thought, and as a result winds may not go near calm. && .Short Term...(This evening through Monday night) Issued at 141 PM EDT Sun Aug 1 2021 Tonight. Any showers associated with the passing frontal system will come to an end by later this evening. With the frontal passage, expect that surface smoke/haze that has been in place will clear which matches up closely with the HRRR smoke guidance. The diurnally driven clouds associated with the front will also exit which will leave behind mostly clear skies and allow for near record cold temperatures tonight across the area as dry air continues to advect into the area. Lows are expected to drop into the mid to upper 50s for much of the area due to the combination of the clearing skies and a dry surface airmass that will optimize radiational cooling. There also may be a few areas of fog towards the morning hours, but with less surface moisture, not expecting as dense of coverage as compared to this morning. Monday and Monday night. Another pleasant day is expected for tomorrow with partly skies and highs in the upper 70s, especially as dew points remain in the upper 50s for much of the area. Northwesterly flow aloft is expected to continue which may bring some lake enhanced cloud cover to the area as slightly cooler air moves over the warmer lake water. The next plume of smoke aloft will arrive tomorrow night, but don`t expect quite the extent of surface impacts due to an expected inversion just off the surface that will limit the intrusion of smoke into the boundary layer. && .Long Term...(Tuesday through Sunday) Issued at 141 PM EDT Sun Aug 1 2021 An upper level trough will remain across the area for much of the long term, before flow becomes less amplified late in the period. During that time, an upper level low may develop. Meanwhile, at the surface, high pressure will be the dominant influence. An inverted surface trough will remain southeast of the area. With high pressure nearby, and surface northeast winds aiding in the overall lack of moisture across the area, feel that chances for any rain are too low to mention through at least Friday (even with an upper low nearby at times). For the weekend, moisture will return as the surface high will be east of the area. This combined with warm temperatures could lead to some diurnal convection by Sunday. Temperatures will remain below normal into mid-week, then warmer air will return. Highs near 90 are possible next Sunday. && .Aviation...(06Z TAF Issuance) Issued at 1148 PM EDT Sun Aug 1 2021 IMPACTS: -Light northerly winds through the overnight. -Some potential for patchy MVFR fog near daybreak at the outlying sites. DISCUSSION: Wind should be out of the north through the overnight hours and much of Monday, with speeds around 3 to 6 kts overnight and 5 to 10 kts from mid morning on. Patchy fog is possible near daybreak, but will be dependent on how much mixing continues through the night. Model trends look less impressive for fog, but not confident enough to pull completely. Will keep tempo MVFR group to cover the potential at the outlying sites. Could then see some few to scattered VFR diurnal cu Monday afternoon. && .IND WATCHES/WARNINGS/ADVISORIES... None. && $$ Update...CP Short Term...White Long Term...50 Aviation...CP
National Weather Service Jackson KY
918 PM EDT Sun Aug 1 2021 .UPDATE... Issued at 918 PM EDT SUN AUG 1 2021 At 1z, a line of struggling cumulus towers with embedded mainly sprinkles/light showers was located was located near an Irvine to Jackson to Prestonsburg line. The western flank of the line over Powell County appears to a bit more organized, courtesy slightly better instability and low-level convergence. Current HRRR trends suggest that this will continue to be the case with the better shower activity generally riding SSE along/just east of the Pottsville Escarpment to near the Hal Rogers Parkway around 3z. This activity should weaken/dissipate as lingering instability wanes. Further east, expect just an isolated shower or sprinkle through 3z. UPDATE Issued at 625 PM EDT SUN AUG 1 2021 A line of low-topped convection is dropping across far northeastern Kentucky this evening, just brushing Fleming and Rowan County with some light to moderate rainfall, a quick 8-10 degree temperature drop, and a blustery NW-N wind gusting 15 to 30 mph. Strong capping at about the -10C level seems to be keeping the convection free of lightning at this time although a couple of cells were able to punch through the cap, up to around -15 to -20C, and produce a few lightning flashes earlier near the Ohio River. Expect that the current line of broken activity will continue to push southeastward at about 25 knots reaching an Inez to Salyersville line around 8 PM or so. Some additional shallow convection is also present from just south of CVG back into southern Indiana. If this activity is able to maintain, expect additional isolated to widely scattered showers sinking southeastward across all but far southern Kentucky during the mid-to-late evening hours. Introduced low chance PoPs and thunder all the way to the Hal Rogers Parkway. Given steep low- level lapse rates and 900-1000 J/kg of DCAPE, the more robust showers could produce some gusty winds but meager MLCAPE (100-500J/kg) and strong capping above 500-600 mb will keep the cells from realizing their full potential. A lightning strike is also possible with any cell that briefly surges above the cap. && .SHORT TERM...(This evening through Monday night) Issued at 425 PM EDT SUN AUG 1 2021 Eastern KY is currently quiet with current temperatures ranging from the upper 70s to around 80 degrees across the area. The 19Z surface analysis shows high pressure dominating over the western CONUS and Northern Plains while a low pressure system resides over the Northeast. A cold front, associated with the low pressure system, is draped through the Ohio valley back into the Central Plains. A fair weather cumulus field has developed over the area and should persist into the evening. The models continue to show decent agreement in the upper level pattern for the short term period. An upper level trough is positioned over the Upper Great Lakes and will continue to progress, east leaving us in a more zonal flow aloft before another trough drops down from the Great Lakes region. This will cause lowering heights aloft over the area into Monday. The aforementioned cold front will move southward, weakening as it approaches the CWA. Cloud cover across the area will increase late this evening into the overnight hours, bring partly cloudy skies for most of the night. A chance for storms and showers is possible with the passage of the front this evening but should remain along and north of I-64. Low temperatures will be in the upper 50s to low 60s with areas of fog possible and denser fog expected in the deeper river valleys. Monday will be dry and pleasant as high pressure continues to dominate to the northwest. Mild temperatures in the upper 70s to low 80s and mostly sunny to partly cloudy skies will make for a comfortable day to spend outside. Fog is expected Monday night but should be less widespread than the previous night with the thickest fog forming in the river valleys. Lows will be in the mid to upper 50s with partly cloudy skies. .LONG TERM...(Tuesday through Sunday) Issued at 315 PM EDT SUN AUG 1 2021 Unsettled weather this week with a trough from the OH valley down to the deep south through mid week before lifting up to New England towards the end of the week, while another trough from the northern plains dives down and impacts the area Friday into the first part of the weekend. At the surface, a frontal boundary will be across the southeast and deep south states with multiple areas of low pressure along the front. None of the days will be washouts, but there will be a chance of afternoon and evening storms each day. Highest chance Pops will be on Tuesday and Wednesday (25-50%) as a theta ridge and increasing PWATS advect into the area. Lower chance Pops (15-30%) Thursday through Saturday with more typical diurnally driven convection expected those days. Below normal temps Tuesday through Thursday with afternoon highs in the lower 80s and low temps in the upper 50s to lower 60s. A bit warmer for Friday into the weekend with high temps in the mid to upper 80s and low temps in the low to mid 60s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 819 PM EDT SUN AUG 1 2021 At 00z, VFR conditions were observed across the area. A southward-dropping cold front was producing a band of variable mid-level cloudiness north of the Mtn. Pkwy. with embedded isolated to widely scattered light showers and virga along its leading edge. This will continue to settle southward through the evening and gradually dissipate toward the Hal Rogers Pkwy. Other than some erratic wind shifts near the shower and virga activity with the leading edge of this cloudiness, no impacts are expected at the TAF sites. Expect winds to become light and variable overnight in most locations with areas of fog, locally dense, developing in the river valleys. Some of this fog or low stratus is expected to eventually creep out of the valleys and bring visibility reductions to the SJS, JKL, and LOZ terminals early Monday morning. Lingering mixing should keep SME fog-free for most of the night but suspect that they too will decouple and eventually see some visibility restrictions. Expect better mixing to keep VFR conditions at SYM, but if winds go calm there, fog formation may ensue. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEERTSON SHORT TERM...BATZ LONG TERM...CMF AVIATION...GEERTSON
Area Forecast Discussion
National Weather Service North Platte NE
616 PM CDT Sun Aug 1 2021 .SHORT TERM...(This evening through Monday night) Issued at 209 PM CDT Sun Aug 1 2021 Mostly quiet weather expected through the short term period. The main weather concern will be possible sfc smoke in the early morning. The HRRR near sfc smoke model runs show some return of sfc smoke early Monday morning, with the greatest area west of hwy 83. Decided to add patchy smoke into the forecast briefly for the morning hours as particulates will likely get trapped in the inversion. Although fog conditions are marginal, there is some concern that the smoke particulates trapped near the sfc will help to induce fog development towards morning, especially in the valleys. As the inversion mixes out by mid morning, smoke/fog concerns will diminish and sfc smoke is not expected to linger. For now have left the forecast with just patchy smoke. For Monday afternoon the HRRR continues to suggest lingering smoke in the upper levels, so have kept haze across a good portions of the forecast area through late afternoon. .LONG TERM...(Tuesday through Sunday) Issued at 209 PM CDT Sun Aug 1 2021 There will be minimal chances for precipitation in the long term. An upper level high continues to sit across the southwest CONUS as northwest flow dominates through most of the work week. There will be weak disturbance that moves through Wednesday. Moisture is expected to return across central and north central Nebraska, but is lacking a little across western Nebraska. Showers and thunderstorms may be possible Wednesday afternoon and evening, the better chance would be across north central and central Nebraska where there would be more moisture available, but even then precip chances are isolated at this time. Temperatures warm into the 90s for the weekend as the ridge becomes centered over the high plains region. As for precipitation chances beyond Wednesday, there will be a weak disturbance Friday night and again Saturday night that could lead to precipitation chances, however at this time confidence is low in anything widespread. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 613 PM CDT Sun Aug 1 2021 Mostly VFR conditions are expected through the TAF period. There is still some existing smoke in the atmosphere creating hazy conditions. As such, have placed a tempo group in for KLBF, and southern Neb terminals, that indicate MVFR VIS conditions at times (down to 4SM). Otherwise, winds will be under 10kts, but a bit variable at the sfc. They will be generally from the south, but may transition between southerly, southeasterly, and southwesterly at times. There are no other flight concerns ATTM. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Gomez LONG TERM...Gomez AVIATION...Sinclair
Area Forecast Discussion
National Weather Service Lake Charles LA
957 PM CDT Sun Aug 1 2021 .UPDATE... Forecast is largely on track tonight with only a couple of small adjustments needed at this time. Firstly, tweaked hourly POPs over the next few hours to account for current radar trends, mainly for the isolated convection ongoing across southern Acadiana. Also tweaked hourly temps to account for current obs going into the overnight hours. Otherwise, still expected a wetter and slightly cooler pattern to begin tomorrow, as a frontal boundary heads towards the coast through the mid-week. 17 && .PREV DISCUSSION... /issued 639 PM CDT Sun Aug 1 2021/ AVIATION... Isolated storms around southeast Texas and southern Louisiana are on the wane this evening although a few storms over by Baton Rouge continue to persist. Looking at all the precip out of the area by 02z but will see some redevelopment after sunrise tmrw as a weak boundary from the northwest and the C-brz collide over the region tomorrow afternoon. PREV DISCUSSION... /issued 358 PM CDT Sun Aug 1 2021/ DISCUSSION... SHORT TERM [Today through 12Z Wednesday]... Showers and thunderstorms continue to develop throughout the area and will be expected to dissipate during the evening hours with loss of daytime heating. A frontal system will be making its way into our area tomorrow which will cause increased chances for thunderstorms starting in the early morning. There will be a broad area of convergence throughout the area tomorrow morning which may cause the development of widely scattered thunderstorms. As the morning progresses into the afternoon, daytime heating will aid development leading to numerous/widespread showers and thunderstorms through the afternoon and evening. The 12Z HRRR shows much of the convection as being disorganized. However, the late evening and overnight hours could see the formation of a squall line of thunderstorms as the front continues to push south (with forced uplift) and tap into moisture from the Gulf of Mexico. WPC has our area in a Marginal Risk of Excessive Rainfall 12Z Monday through 12Z Tuesday. Significant accumulation will be expected which could lead to flooding. The front will provide enough instability to keep precipitation chances elevated through to the end of the period. 55 LONG TERM [Wednesday through Sunday]... The unseasonal, but most welcome frontal boundary is expected to stall over the northern gulf by Wednesday morning. Scattered to widespread showers and thunderstorms are likely to persist over the coastal waters in the vicinity of the front. As with the previous cycles, NBM along with most of the regularly produced blended guidance appear to be significantly overestimating inland PoPs both Wednesday and Thursday likely due to the inclusion of previous, less certain, runs as part of their algorithms. The official forecast pares PoPs back to isolated along and south of the I-10 corridor and even this may be generous should the front make it further offshore than currently projected. Both high and low temperatures behind the front will be marginally "cooler" although afternoon highs will still climb into the lower 90s. Dewpoints, however, will drop back into the mid to upper 60s across central Louisiana and lower 70s closer to the coast which will keep heat indices more tolerable through Thursday. The frontal boundary will gradually wash out over the coastal waters as a weak surface high develops across the northeastern gulf Friday. This will turn low level winds back out of the south and push gulf moisture back across the region. The upper trof responsible for the frontal passage will lift off to the northeast as a second trof digs out of Canada across the central U.S. No real change in airmass with this trof, but it will likely provide better upper level support for diurnally driven convection into next weekend. Jones && .PRELIMINARY POINT TEMPS/POPS... AEX 75 89 73 89 / 40 100 70 50 LCH 78 91 74 89 / 40 90 90 80 LFT 77 91 75 89 / 40 90 90 80 BPT 77 92 74 89 / 30 80 90 80 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$
Area Forecast Discussion
National Weather Service Louisville KY
736 PM EDT Sun Aug 1 2021 ...Updated Aviation Discussion... .Short Term...(This evening through Monday) Issued at 300 PM EDT Sun Aug 1 2021 Latest GOES imagery shows scattered cu field across much of our region with some haze mixed in. More congested area of clouds blanket counties just north of our CWA, associated with a south- bound cold front that is attached to a sfc low currently located over Lake Ontario. Regional radar shows a line of progressive showers already developed over east-central IN and central OH and tracking to the southeast. As this cold front arrives in our region this evening, some isolated showers are possible despite a relatively dry environment with PWATs around 1.1 inches. Hi-res model consensus is that counties east of I-65 will have the best chance of a shower, which agrees well with RAP guidance on suggesting slightly better moisture convergence to our east. Additionally, model soundings show a strong inversion around 700- 600mb developing this afternoon, which will limit any updraft growth, resulting in shallow showers and light QPF. Will limit PoPs to no more than a slight chance, and believe more people will remain dry than those that do observe any precip. Other topic of discussion for this afternoon and evening is the haze/smoky conditions from western wildfires. Expect these hazy conditions to remain through this evening, providing a red-orange sunset, before clearing out of southern IN and Louisville Metro by 05z, and Lexington/Bowling Green by 08z. With mostly clear skies and relatively calm winds overnight, expect to have some early morning patchy fog develop across our southern CWA, specifically the Cumberland Parkway corridor and Bowling Green region. Fog should burn off quickly after sunrise tomorrow morning, but some folks with an early commute could see some rapid changes to visibilities. Temperatures for tonight will range from mid 50s across southern IN to low 60s across south-central KY. Tomorrow will be a rather comfortable and mostly sunny day across the region, with temps expected to stay in the upper 70s to low 80s, with dewpoints in the upper 50s and near 60. Haze looks to make a return to Louisville and Lexington by tomorrow afternoon. .Long Term...(Monday night through Sunday) Issued at 245 PM EDT Sun Aug 1 2021 =================================== Synoptic Overview =================================== Overall pattern for the upcoming week is similar to the overall pattern that we`ve seen so far this summer. Broad upper ridging is forecast to persist across the western US with a troughing centered east of the Mississippi River Valley. This pattern looks to hold steady through at least mid-week. Towards the end of the week, the broad trough axis over the east is expected to deepen and will likely close off. This upper low will likely remain over the Ohio Valley for the late part of the week which will likely fuel diurnally driven convection over parts of the area. By next weekend, the pattern is expected to flatten out a bit and become a bit more progressive, yielding seasonal temps but episodic bouts of precipitation. =================================== Model Discussion/Preferences =================================== Deterministic and ensemble guidance remains tightly clustered and in remarkable agreement through much of the forecast period. Increasing, but normal spread begins to show by day 4 and continues through day 7. Overall, the spread is not bad and certainly lower than normally seen out through day 7. Given the good agreement, the blended model suite looks to be a good basis for the upcoming forecast. =================================== Sensible Weather Expected =================================== In terms of sensible weather, cooler than normal temperatures with lesser amounts of humidity are expected through mid-week. Morning lows will start off in the upper 50s across southern Indiana and northern Kentucky with upper 50s to the lower 60s across southern Kentucky. Daytime highs on Tuesday will be in the upper 70s to around 80. Highs on Wednesday should be similar, though southern Kentucky should warm solidly into the lower 80s. Inverted surface troughing may take shape by Wednesday as aforementioned upper low closes off over the eastern part of the Ohio Valley. That should allow for scattered convection to develop over mainly eastern KY (along and east of the I-75 corridor). Previous forecast had this covered well and the latest data continues to support that trend. With the upper level low nearby, we will likely see mainly diurnally driven convection fire each afternoon from Thursday through Saturday. Overall, this doesn`t appear to be a washout by any means, but the highest chances of precipitation look to remain east of the I-65 corridor through the period. Temperatures Thursday through Saturday will continue to run slightly below normal with highs mainly in the lower-middle 80s and overnight lows in the 60s. =================================== Forecaster Confidence =================================== Temperatures: Medium to High through the period. Precipitation: Medium to High through Wednesday. Medium Thursday through Sunday. && .Aviation...(00Z TAF Issuance) Issued at 735 PM EDT Sun Aug 1 2021 Scattered showers have developed along a cold front pushing south through southern IN and northern KY this evening, so did include a brief VCSH at SDF and LEX. Northwesterly winds veer northerly tonight in the wake of the front and diminish slightly after sunset. Haze will continue to lower visibility into the 6-8 SM range this evening. Expect light northeasterly winds on Monday with just some sct afternoon cumulus. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Short Term...CJP Long Term...MJ Aviation...EBW
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 311 PM CDT Sun Aug 1 2021 Northwest flow aloft will dominate the region the next several days. In the short-term this will allow for smoke to continue over the area, though lessened, through tomorrow at least. The latest HRRR smoke forecast depicts smoke lingering more into western Iowa and central Nebraska through the evening and overnight hours. Otherwise quiet weather will be the rule. A weak shortwave passes through the area Wednesday night but with an overall meager moisture profile precipitation chances are not great and barely worth mentioning. The main focus the next week is the building heat. By next Friday daytime highs return to the 90s, possibly reaching 100 in some areas by next Sunday. This coupled with dewpoints in the 60s and low 70s will push heat index values to around 105, flirting with heat advisory criteria for a large portion of the area. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 611 PM CDT Sun Aug 1 2021 VFR conditions (visibility greater than 6 SM and SKC-SCT AOA 5000 ft AGL) should be predominate through the next 24 hours. There is about a 30% chance for reduced visibilities (3-6 SM) due to smoke between 12Z and 23Z Monday. However confidence in these visibility restrictions was to low to warrant there inclusion in the TAFs (KOMA, KLNK or KOFK) at this time. Winds should remain light and variable through the next 24 hours. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Pearson AVIATION...Albright
Area Forecast Discussion
National Weather Service Mount Holly NJ
818 PM EDT Sun Aug 1 2021 .SYNOPSIS... A cold front will cross the region tonight, at the same time a wave of low pressure passes well offshore. High pressure builds in for Monday and Tuesday. A frontal zone will set up near our coastline for the midweek period, with multiple waves of low pressure tracking along it. High pressure may build back in towards the end of the week or next weekend. && .NEAR TERM /THROUGH MONDAY/... Showers with some isolated embedded thunderstorms associated with a cold front are approaching the region from the north and west. These shower are the result of a strong upper level trough digging into the region with quite a bit of mid/upper level shear. However as we head into the overnight hours the instability will wane and the showers will start to lack the support for stronger updrafts. The HRRR shows this quite well as the vertical velocities dramatically weakening over our area. The forecast largely had this covered and so no significant changes were made to the forecast other than to slightly delay the timing of the precip over the southern portion of the forecast area. The cold front approaching from the northwest is then anticipated to pass through our region late tonight, bringing a decrease in cloud cover by daybreak on Monday. Monday should then be mostly sunny with a NW breeze and highs in the 70s to low 80s. && .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... High pressure continues to control the weather Monday night into Tuesday. Monday night looks like a cool one under favorable radiational cooling conditions, with lows likely falling into the 50s outside of the warmer urban centers and Delmarva. Tuesday looks like a pleasant day as well. A shift to light onshore flow is likely as the center of high pressure weakens and shifts offshore. Tuesday will also offer noticeably more cloud cover, mainly in the form of mid and high level clouds and especially towards the coast. This will come as a baroclinic zone offshore becomes more convectively active to our south, with mid and upper level winds carrying cloud tops northward. Locally, however, dry weather is expected to prevail due to lack of forcing and a large amount of dry air remaining in the low to mid levels. Temperatures look similar to Monday, near 80 in most areas. By Tuesday night, rain chances start to creep up in the southeastern portion of the area as the first of several surface waves starts to approach along the baroclinic zone. Even then, however, timing and track of the wave should work out such that any rain should remain confined to areas near the coast. Areas along and northwest of I-95 will stay dry through Tuesday night. Lows favoring the upper 50s and low to mid 60. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Overview... The big story for the long term will be the return of sustained humidity as our region becomes entrenched in a funnel of moisture between an offshore Bermuda High and Great Lakes/Ohio Valley troughing. Little change in thinking to the previous forecast, with the main source of uncertainty being precipitation chances as several waves of low pressure track along a nearby baroclinic zone. It looks like most of these waves will largely stay offshore, though at least one on Thursday may deliver a soaking rain. The end of the work week and next weekend then look to transition to a very typical summer pattern of warm and humid weather and spotty, diurnally driven convection. Dailies... Wednesday-Wednesday night... Latest trends suggest Wednesday has a good chance to remain mostly dry, especially away from the coast. The 01.12z NAM was an outlier in showing a soaking rain on Wednesday, and have largely discounted it. Most indications are that the flow will not amplify enough on Wednesday to draw that wave very far northwest. For PoPs, split the area roughly into thirds from northwest to southeast, with values ranging from below mentionable (northwest) to slgt chc (central) up to chc (southeast). Highs mainly in the low 80s are expected. A similar theme with the rain chances through the night with lows from the upper 50s to mid 60s. Thursday-Thursday night... If there`s going to be a washout day this week, it will be Thursday. The GFS is trending more towards the EC/UKMET solutions of bringing the next frontal wave directly over the region, though the GFS still shows it just scraping the coast. Raised PoPs to likely over much of the region. The wave looks fairly progressive, but the EC/UKMET do show it producing significant rainfall in a fairly short amount of time. So we will have to keep an eye on excessive rainfall potential. The wave should start to pull away by Thursday night. Friday-Friday night... Most guidance suggests the wave from Thursday departing by Friday, leaving drier weather in its wake. With more sunshine, temperatures should rise well into the 80s with fairly high humidity on light southwest flow. This could lead to some spotty air mass showers or storms in the afternoon. Because of this and the low chance of a slower departure of the Thursday wave, still have slgt chc PoPs for much of the region. But overall this is looking like a mostly dry day and night. Saturday-Sunday... Southwest flow likely continues into the weekend, leading to a little more warming and a continued increase in humidity. Rain chances look fairly limited, but some isolated, weakly forced convection could be possible on either day. As usual at this range, some room for change in next weekend`s forecast, but definitely looks like what you would expect for the first weekend of August. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Mainly VFR. MVFR...both ceilings and visibilities... possible during the evening hours due to showers and thunderstorms. Best chance of thunderstorms from the I95 terminals north and west. S winds 10 kts or less, becoming NW. Generally high confidence, except for the thunderstorm placement. Monday...VFR. NW winds 5-10 kts gusting to 15 kts during the late morning and afternoon hours. Outlook... Monday night-Tuesday... VFR. Near calm winds Monday night. Winds on Tuesday will become northeast then shift to southeast, but with speeds only around 5 kt, and they may remain light and variable in some areas. High confidence. Tuesday night... Initially VFR. The development of sub-VFR conditions is possible southeast of PHL and especially near the coast as the night goes on. Winds mostly light and variable or calm but favoring onshore directions if anything. Moderate confidence. Wednesday-Wednesday night... Mainly VFR for areas near and southeast of PHL, though cannot rule out some MVFR. A better chance of restrictions towards the coast, especially near ACY. East-northeast winds 5 to 10 kt, decreasing overnight. Moderate confidence. Thursday-Thursday night... MVFR/IFR possible in rain, which may be heavy. Light northeast winds shifting to southeast during the day then becoming light and variable at night. Moderate confidence. Friday-Friday night... Mainly VFR. Light southwest winds. Moderate confidence. && .MARINE... Winds should continue to be south to southeast 10 to 15 knots through this afternoon. The wind is expected to shift to the northwest tonight with the arrival of a cold front. Waves on our ocean waters should range from 2 to 3 feet with waves on Delaware Bay at 2 feet or less. For Monday, Seas 3-4 ft with NW winds sustained around 10kts with gusts to 15kts. Outlook... Monday night-Friday... Mostly sub-SCA conditions expected. A couple of wind shifts expected but gusts mostly 20 kt or less through the period. Seas 2 to 4 ft, possibly close to 5 ft during the midweek period. Frequent opportunities for showers and isolated thunderstorms from late Tuesday onwards. Rip currents... A southeast wind 10 to 15 MPH is expected for today. Breaking waves around 2 feet are anticipated with a medium period southeasterly swell. The forecast conditions should result in a LOW risk for the development of dangerous rip currents. However, the risk may approach moderate in spots this afternoon, so use extra caution if entering the surf. The wind is forecast to be from the northwest on Monday morning with a sea breeze possibly developing in the afternoon. Breaking waves are again expected to be around 2 feet and the rip current risk will likely be LOW. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...None. NJ...None. DE...None. MD...None. MARINE...None. && $$ Synopsis...O`Brien Near Term...Deal/Fitzsimmons Short Term...O`Brien Long Term...O`Brien Aviation...Deal/Kruzdlo/O`Brien Marine...Fitzsimmons/O`Brien