Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/26/21

Area Forecast Discussion
National Weather Service La Crosse WI
1102 PM CDT Fri Jun 25 2021 .SHORT TERM...(This evening through Saturday) Issued at 251 PM CDT Fri Jun 25 2021 Surface analysis shows a frontal boundary extending from lower Michigan through northern IL/central IA. Behind this front, which passed through last evening/overnight, leftover low level moisture from shower/storms was producing widespread low clouds and pockets of drizzle/isolated showers across the forecast area today. Temperatures as of 2 pm were in the mid 70s to lower 80s with muggy dew points in the mid 60s to lower 70s. For tonight, a mid-level shortwave trough (currently moving out of WY int NE per GOES water vapor) will spin up surface cyclogenesis over the Central Plains. This low will track along that aforementioned frontal boundary, lifting north as a warm front to along I-90 by Saturday morning. Increasing moisture transport ahead of the low and into the warm front is expected to spread showers and storms into the area tonight. The showers and storms look to be fairly widespread going into Saturday as the low tracks through southern WI. Airmass going into Saturday will be rather soupy as well with dew points in the 65-70 degree range/precipitable waters around 2 inches. So, could see some localized heavier rainfall under storms. In addition, with the low track, could see a small window of strong to severe storms in the warm sector across portions of northeast IA into southern WI where greater chance of destabilization takes place. Otherwise, plan on highs mainly in the 70s, maybe a few lower 80s. .LONG TERM...(Saturday night through Friday) Issued at 251 PM CDT Fri Jun 25 2021 Through much of this period, a longwave trough will remain across the region. As shortwaves move through this trough, there will periodic chances of showers and storms. The timing of these waves are highly uncertain, so they are broad brushed through this time period. High temperatures will range from the mid 70s to lower 80s. Low temperatures will range from the lower 50s to lower 60s. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 1055 PM CDT Fri Jun 25 2021 Abundant low level moisture will bring low ceilings into the TAF sites early Saturday morning. IFR ceilings are likely at both RST and LSE towards daybreak and are expected to persist for much of the period, perhaps improving slightly to low MVFR in the afternoon. Can`t rule out some patchy fog before daybreak, but any visibility reductions the rest of tonight would be more likely tied to passing showers and/or storms that come into play roughly after 09Z. Low pressure and a warm front lifting northward on Saturday will bring numerous showers and storms through the area during the day. Recent HRRR runs suggest only isolated convection through mid- morning, and then fairly widespread activity over the TAF sites from about 17Z to 03Z Sunday along the front as it stalls overhead. Any slow-moving showers and storms will be capable of dumping heavy rainfall over a short period of time. Also can`t rule out a few stronger storms with gusty winds, mainly for LSE. Outside of any stronger storms, winds should be mainly light around 10 knots or less through the period. Direction will fluctuate depending on the position of the front. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...DAS LONG TERM...Boyne AVIATION...Kurz
Area Forecast Discussion
National Weather Service Bismarck ND
928 PM CDT Fri Jun 25 2021 .UPDATE... Issued at 921 PM CDT Fri Jun 25 2021 Showers are still slow to move out of the far south central and the James River Valley along an inverted surface trough, but the threat of thunder seems close to zero at this point so took the mention out of the forecast through 15z tomorrow. Also evaluated the fog potential a bit closer. There is still some potential for patchy fog tonight in areas that saw rain over the past two days. However, we remain skeptical that there will be enough clearing for widespread fog. Will continue to leave mention out of the forecast for now. UPDATE Issued at 608 PM CDT Fri Jun 25 2021 The main area of showers continues to extend from the far south central northeast and into the Jamestown and Carrington areas. While most of this rain has been light to moderate, the line itself has been fairly slow to move east. Thus, a few areas have received an inch or more of beneficial rainfall. While thunderstorms haven`t really materialized this afternoon, will keep a slight chance of thunder in the forecast as a few hundred J/kg of CAPE are still floating around. A few lingering showers will be possible through the night behind the main line. Will have to revisit fog potential for the next update as some of the CAMs are wanting produce some patchy fog along and east of the Missouri River. This seems reasonable with light winds forecast and a moist ground, but there still remains quite a bit of uncertainty if the sky will clear enough. Thus, will leave it out of the forecast for now. && .SHORT TERM...(This evening through Saturday) Issued at 153 PM CDT Fri Jun 25 2021 Scattered to numerous shouts and isolated thunderstorms continue to track eastward through central ND this afternoon. It looks like the last chances for thunder are currently moving through Mandan and Bismarck. Latest surface analysis shows surface low pressure near The SD border around the Missouri River Valley. Latest RAP analysis shows around 250 j/kg Cape around Bismarck to around 750 j/kg near Linton/Selfridge area. Strong vort max around Garrison to Minot continues to produce widespread showers and embedded thunder over central into northeast ND. The activity does scatter out however over the south central. The associated shower activity along the vort tail extend southwest to just west of Mandan and then to western Sioux county. Think we would have maybe an hour to possibly two in the local Bis/Man area for thunder before thunder and shower chances really drop off. Better rain chances remain just east of Bismarck and Linton/Selfridge area into the James River Valley. However, if mid level lapse rates remain meager, it looks like a continuation of shower activity with isolated thunder. Shower activity will linger over the James River Valley through much of the night, with another chance of showers moves into northwest ND ahead of a shortwave dropping south from Canada. Expect Mostly cloudy skies tonight with lows in the mid 50s to lower 60s. A few lower 50s or even upper 40s area possible over thee southwest where we see the best chance of a period of clear skies between the exiting shower activity southeast and the next system moving in from the north. The wave dropping south from Canada will keep scattered showers and isolated thunderstorms in the forecast through the day Saturday. Activity will not be as widespread as today with the best chances for thunder in the south central late afternoon or early evening. Severe weather is not anticipated. Highs are expected to be mainly in the 70s, but with a few lower 80s possible. .LONG TERM...(Saturday night through Friday) Issued at 153 PM CDT Fri Jun 25 2021 Shower and thunderstorm chances Saturday night and Sunday followed by mainly dry conditions and a warmup through the work week. The aforementioned system dropping through on Saturday could keep some lingering shower chances through Saturday night. Then one last shortwave drops south through the area on Sunday bringing another chance of showers with isolated thunderstorms possible. Then mainly dry conditions with a warming trend look to be in store through the first half of the work week. A strong upper ridge building over the Pacific Northwest this weekend will push slowly eastward into the northern Rockies early next week. There remains some uncertainty on how this strong ridging evolves late in the work week and into next weekend. Like this weekend there is now some support for a northern stream system dropping into the Northern Great Lakes region, or the Northern Plains, and how this might impact the upstream ridge. A look at the cluster analysis for late next week shows support for both a ridge dominating the forecast area, and also upper troughing over the central plains into the Great Lakes, which would lead to more tempered heat, especially over eastern portions of the forecast area. With this and a pretty wide spread of the NBM ensembles toward next weekend, we will leave the extended forecast as is. Highs generally in the 80s, with some 70s possible early in the work week and inching toward the 90s west, late in the work week. After this weekend, no significant chances for precipitation are in the forecast next Monday through Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 608 PM CDT Fri Jun 25 2021 Showers will continue for the next few hours, mainly east of the Missouri River and into the James River Valley. The site most impacted by these showers will be KJMS, but some lingering showers will be possible in the vicinity of KBIS. If skies can clear enough we may see some patchy fog across the central and east with light winds in the forecast and moist ground. However, uncertainty regarding the cloud cover precludes mention of fog in the TAF at this time for any particular site. Widely scattered showers and a few thunderstorms will possible once again across all of western and central North Dakota Saturday afternoon. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...ZH SHORT TERM...TWH LONG TERM...TWH AVIATION...ZH
Area Forecast Discussion
National Weather Service State College PA
1103 PM EDT Fri Jun 25 2021 .SYNOPSIS... An anomalous upper level ridge over the north Atlantic will build and retrograde westward into the Mid Atlantic region this weekend through early next week, bringing a gradual increase in heat and humidity. A slow-moving cold front is then likely to push into Pennsylvania late next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Latest radar trends show very light rain showers moving in from the west and drying up across the northern Alleghenies. Farther upstream, heavier showers continue between Cleveland and Erie along a warm front. Hires guidance shows this precip lifting northward into the Glakes/NY through the overnight. Thus knocked PoP below 25% in the NW zones. Over the eastern part of the state, a marine layer will slide up the coast and bring low clouds and moisture after midnight. This could produce a bit of late night drizzle over the western Poconos, as moist low level southerly flow is forced to ascend the higher terrain. 0-1km RH values approach 100 pct in this area late tonight. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Low stratus over the SE will erode by mid morning Saturday. Took temperatures down a few degrees vs the NBM for the morning hours in this area, but thinking temps will rebound quickly in the afternoon, coming back in line with the NBM guidance after 18z. Latest HRRR shows a few showers popping in the lower Susq late morning / early aft on Sat, as low stratus mixes out but high dwpts remain in the midst of increasing instability. Will raise PoPs up to slight chance in this area to account for this. Capping at 700 mb should prohibit tstms. Warmest thermal axis at 850 mb sets up over the western half of PA Sat afternoon as warm air spills in from the west. This, combined with early cloud cover in the east, will likely result in only a few degrees difference in MaxT between BFD and MDT. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Very little to change/add to the previous disco with this late evening update. HHH is on the way. Mon-Wed still looks like a solid chc for a Heat Advy (100+ HI) in the Lower Susq. Still playing temps a deg or two cooler than blend of guidance thru that period. Prev... All guidance supports rather hot and humid conditions Sunday (and on average 7-10 deg F above normal) but, with anomalous upper ridge centered just off the Mid Atlantic coast. Warm temps aloft should largely suppress PM convection. However, can`t rule out an isolated, pulse-type shower/storm developing over the elevated heat source of the Appalachians. Mixing down model 850mb temps of around 18C translates to highs ranging from the mid 80s over the highest terrain of the Alleghenies, to the low 90s in the Susq Valley. Guidance continues to depict a western Atlantic ridge moving westward over the Eastern US and amplifying throughout the weekend into next week. Anomalously high 850mb temperatures along with the southerly surface winds will allow most locations to see temperatures rise above normals into the mid to upper 80s, with some locations peaking into the low 90s. The heat will be accompanied by increasing dew points, which may result in heat indices climbing into the mid 90s. The warm moist airmass will also introduce the chance or diurnal convection. Lack of deep layer shear will likely keep any storms below severe limits. The heat, humidity, and daily chance of scattered afternoon showers and storms will continue through the week until a cold front sweeps across the region late Thursday into Friday. There is a degree of uncertainty to the strength and timing of this front due to model differences. Late next week into the holiday weekend, the GFS stays dry while the EC is wetter, so the conditions of the holiday weekend are very uncertain. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Latest nighttime satellite imagery shows low clouds developing across mid Atlantic through the DC area and spreading northward within a marine layer. Low clouds will push into the central/southeast airfields after midnight tonight with a stray shower possible mainly east of the Susquehanna River or in the Northern Alleghenies. Expect several hours of MVFR cigs at MDT/LNS and possibly at IPT/UNV, with a period of IFR cigs also possible for LNS and perhaps MDT prior to daybreak. Cigs will lift and scatter out from southwest to northeast through the morning hours Sat, with all airfields likely back to VFR by 15z. Expect winds to continue from the south with afternoon gusts 15-20 kts. Outlook... Saturday...Improving cigs east w/ showers/storms possible mainly in northern PA. Sunday...Scattered afternoon thunderstorms with brief, localized restrictions. Monday-Tuesday...More numerous, mainly afternoon and early evening showers and thunderstorms as a slow moving cold frontal boundary slides east across the state. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert/Colbert SHORT TERM...Lambert/Colbert LONG TERM...Dangelo/Wagner AVIATION...Lambert/Colbert
Area Forecast Discussion
National Weather Service Des Moines IA
716 PM CDT Fri Jun 25 2021 .DISCUSSION.../Tonight through Friday/ Issued at 301 PM CDT Fri Jun 25 2021 Today and Saturday: The large-scale pattern across the central CONUS remains under the influence of a broad trough, keeping mid to upper-level flow west- southwesterly. The short-wave that triggered last night`s convection has moved into the Great Lakes Region. There has been subtle hints of subsidence across portions of central and northwestern Iowa via satellite imagery, but plenty of lingering moisture is still present and several areas have remained under overcast skies. Additionally, the activity last night has left several outflow boundaries across the region, and these can be seen by variable wind directions across the upper Midwest as well as sudden discontinuities in temperatures and dewpoints. Another vort max is moving across the central Plains this afternoon will be moving through Iowa during the evening hours, continuing overnight. While this is ongoing, a surface low developing near the OK Panhandle will begin to slowly lift northeast across Kansas toward the area. This will continue to push warm moist air into the region, and provide weak lift for shower and thunderstorm generation. There is still some question as the strength of convergence that will be available, because synoptically there will not be much this afternoon. However, differential heating this afternoon where skies clear could potentially strengthen one of these outflow boundaries in the region, which could increase the convergence and thunderstorm potential. CAMs today initiate weak convection across eastern portions of the forecast area after 18z today, though these are not maintained for a long period of time. After 20-21z, there is more development in the CAMs as the mid-level vort max moves across the area. This is mainly focused for areas north of Interstate 80, where there currently sits a stationary boundary. There will be a decent amount of instability throughout most of the forecast area, with the RAP continuing to depict nearly 2000 J/kg of SBCAPE. However, mid-level lapse rates are not exceeding 7.0 C/km north of Interstate 80 this afternoon where convection is expected to initiate. This will make it difficult for strong updrafts to get going. Flow in the lower-levels of the atmosphere remains weak, and does not increase until above 500 mb. Therefore, the deep layer shear will be rather weak for a large amount of time. It may increase later into the evening. Even if parcels become surface based, there will not be a whole lot to organize it until well above the CBL. This complicates the severe threat with these storms. With the overall lack of lower level flow, the tornado threat does not seem present. The only factor that could change this is activity in the immediate vicinity of an outflow boundary, but it will have to be timed and located perfectly. With moderate instability, deep convection will still present hail and stronger wind chances this evening for areas north of Interstate 80. Late in the evening, as the surface low continues to move northeastward, convergence then increases in for areas south Interstate 80, and CAM guidance this morning has had decent agreement on stronger convection after 04z continuing into Saturday morning. Like with the convection to the north, hail and wind gusts could be possible, but low-level flow will still be lacking in this area and thus not much deep layer shear, thus only the marginal risk for severe weather this evening. Once again, flooding may become an issue. For the convection north of Interstate 80, motion may occur parallel to the stationary boundary that is in place. Storm motions will not be overly fast, meaning that an efficient storm could drop a lot of rainfall over just an hour or two. Areas north of Interstate 80 though will still be able to handle heavier rainfall before major issues start to arise. The bigger flooding concern will areas south of Interstate 80. Last night flooding occurred as some thunderstorms cumulatively produced 4 to 6 inches of rainfall over a 6 hour period. This same area may be able to see another 1 inch tonight, with locally higher amounts likely. Flash Flood Guidance indicates that 1 to 1.5 inches over 3-6 hours could trigger more flooding, especially south of Interstate 80. Therefore, have issued a Flash Flood Watch through Saturday morning for southern portions of the forecast area. This first round of convection will move east-northeast by 12-14z timeframe, as the low surface low pressure moves across the state. The larger short-wave trough axis will begin to slide eastward, continuing weak H5 height falls into Saturday afternoon. Behind the surface low pressure system will be a cold front, a main convergence source for shower and thunderstorm activity on Saturday. GFS depicts an environment with SBCAPE over 2000 J/kg ahead of the cold front during the afternoon, with other guidance between 1000-1500 J/kg. However, convective debris from the earlier morning activity may hinder destabilization Saturday afternoon ahead of the boundary. If destabilization occurs, low-level flow should be a bit stronger than it is today as the surface low moves across the area, with plenty of deep layer shear still around to support the organization of a few storms. With this possibility, the marginal risk has been expanded to cover more of Iowa for severe storms on Saturday. The threat at this time remains very conditional. Extended: Persistent southwest flow will bring several short-wave perturbations across the region for the rest of the week. Expect multiple rounds of rain showers and thunderstorms. Temperatures will range from the mid 70s to the mid 80s throughout the week. By the middle of the week, GFS and ECMWF continue to resolve the high pressure over the eastern CONUS differently, with the GFS stalling out the high pressure creating blocking pattern through the week. There will be dry periods throughout next week, but given the uncertainty of how long this trough will be parked across the Midwest, have not deviated much from blended guidance in the extended forecast. && .AVIATION.../For the 00Z TAFS through 00Z Saturday evening/ Issued at 715 PM CDT Fri Jun 25 2021 Scattered showers and thunderstorms will persist for much of the forecast period across central Iowa. Mostly VFR ceilings but increasing MVFR coverage overnight into Saturday morning as precipitation persists. Winds will be variable at 5 to 10 mph for much of the period with stronger gusts in and around thunderstorms. && .DMX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 7 AM CDT Saturday for IAZ084>086-092>097. && $$ DISCUSSION...Krull AVIATION...Cogil
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1005 PM EDT Fri Jun 25 2021 .UPDATE... Pronounced convectively enhanced shortwave anchored over southeast Michigan late this evening. Infusion of larger scale mid level ascent still proving efficient within the background of a highly moist, weakly unstable environment -- supporting a persistent, chaotic coverage of showers locally. Radar trends suggest a window of greater stability will emerge within the immediate wake of this vort max across northern sections, offering a brief reprieve from convective potential overnight. Southern sections remain more susceptible to development, owing to steady nocturnal moisture flux and effective retention of a weakly unstable profile under persistent 30-40 knot southwest flow across the 850-925 mb layer. Recent HRRR guidance points to an increase in shower coverage from south to north through the morning hours within this pattern, likely augmented by the northward migration of the composite frontal zone/outflow now fixated near the OH/MI border. Locally heavy rainfall a clear risk to accompany any development, but window for possible organized convection and accompanying severe risk remains muted given limited instability. Minor evening forecast update to account for near term trends and expectations for the remainder of the night. && .PREV DISCUSSION... Issued at 749 PM EDT Fri Jun 25 2021 AVIATION... Southeast Michigan arrives within the immediate wake of an exiting mesoscale convective complex late this evening. A general increase in larger scale subsidence and resulting deeper layer stability suggests diminishing potential for additional convective development prior to 06z. Lingering pockets of showers may afford brief disruption to visibility, but a larger scale response appears unlikely. Very moist low level profile ensures a high coverage of MVFR stratus tonight, but with a persistent southwest gradient limiting prospects for fog development despite the high near surface moisture content and recent rainfall. Gradual mid level destabilization occurs as the main moisture axis lifts back northward late tonight and Saturday. Recent model guidance suggests a gradual increase in coverage of showers from south to north during the morning period. Confidence in thunderstorm coverage and timing Saturday remains very low. For DTW...Lingering showers in MVFR within prevailing southwest winds this evening. Increasing stability precludes including a defined mention for thunder going forward tonight. Greater risk for thunderstorms appears to develop north of DTW Saturday. DTW THRESHOLD PROBABILITIES... * High for ceiling at or below 5000 feet through the TAF period. * Low for thunderstorms tonight and Saturday. PREV DISCUSSION... Issued at 416 PM EDT Fri Jun 25 2021 DISCUSSION... Areas generally along and south of I 96 have been upgraded to a Slight Risk with a 5% tornado probability. The potential for tornado development remains highly conditional to any breaks in the cloud. Need to stress it will only take a short time period of insolation to generate surface based instability given peak late June incoming solar radiation power. Most recent hires soundings point to a relatively shallow high CAPE density profile that is typical in mini- supercell setups along with very low LCL heights. Given vorticity rich environment immediately in advance of MCV feature, the potential exists for mini-supercell activity for any area that experiences sunshine between 20-02Z. See Update discussion issued earlier for more information. Will continue to monitor observed rainfall amounts versus forecasted QPF totals over the coming forecast periods for the need of a Flash Flood Watch or Flood Watch. The main deep moisture axis or atmospheric river of near/greater than 2.0 inch PWAT that MIMIC-TPW product shows overhead is forecasted to remain in vicinity of Southeast Michigan through the upcoming weekend. However, the details do matter as model data does show a northern migration of the axis to points along and north of M46 by midday Saturday, then eventually wavering down to south of I 94 and south of Michigan border by late Sunday. Low confidence exists and it remains difficult to pin down exactly where deep convective/highest rainfall rates on a 6 hour by 6 hour basis. Because of this low temporal/low spatial certainty, will be forgoing the issuance of a Flood Watch or Flash Flood Watch this issuance. Given dry antecedent soil conditions and relatively lower amounts the feeling is that any flooding issues this evening can be addressed with short fuse Urban/Small Stream Advisories or Flash Flood Warning. Anomously, deep upper level composite trough digging into the Dakotas and corresponding height falls will cause main baroclinic zone axis to lift northward as a warm front on Saturday. Models disagree on amount of activity before noon, with latest extended runs of HRRR relatively dry and HREF 6 hourly ensemble mean rainfall amounts of less than .5 inch. By afternoon, two items worth monitoring will be severe weather risk, and the potential for the training of convection during the late afternoon and evening. Latest Swody2 includes Southeast Michigan as a Marginal Designation for severe weather. All indications are that opacity of cloud will be less which will result in greater destabilization acorss the cwa. Model soundings support low convective heights resulting in surface based and mixed layer CAPES of potential 2000 J/kg or greater. Main axis of kinematics will reside over north half of Lower Michigan including northwern sections of the cwa, 0-6km bulk shear of +35 knots. Unidirectional wind direction and approximately 50 knots wind magnitudes down to 4000 ft agl points to much more organized damaging wind potential. The low confidence part of the forecast moving forward is exactly where the activity is favored, models suggest some capping/CIN centered at roughly 5.5 kft agl building in from the south. Attm, the higher potentia for linear mode/smaller dyanmic bow echo activity appears to be north of I 69. With that stated, the potential for large Cape density through the tropopause and hires signal for discrete cells may potentiall bring all severe types in play. Increasing upper level jet entrance region dynamics combined with deep potential vorticity reservoir is expected to result in low pressure tracking across portions of Wisconsin and northern Great Lakes/SOO on Sunday. A ton of questions exist on where exactly the deep synoptic forcing will occur. However, high confidence exists that main midlevel moisture axis 700-500mb will reside directly over Southeast Michigan during the day on Sunday. Models do suggest a persistence setup with diabatic heating leading to 1500-2000 J/kg surface based CAPE and unidrectional southwest wind profile. Latest Swody3 includes Southeast Michigan in a Marginal Risk for Severe weather. MARINE... Unsettled weather continues over the central Great Lakes today into tonight as a wave of low pressure tracks along a stalled frontal boundary. Moisture is abundant across the region with numerous showers, heavy at times, and a few thunderstorms likely to continue. Wind gusts will generally remain between 20 and 25 kt through midnight with Small Craft Advisories in effect for all nearshore waters outside of Saginaw Bay. Any thunderstorms will have potential to produce locally stronger winds and higher waves which would lead to localized hazardous boating conditions as well. Southeasterly winds this afternoon veer to southwesterly tonight as the low pressure departs the region. A brief lull in precip is possible early Saturday, but another round of showers and storms is then likely the rest of the day as southwest flow advects in another surge of moisture. A second round of Small Craft Advisories may be needed over western Lake Erie and Lake St. Clair on Saturday. Numerous showers and storms are likely to continue Sunday and into the early week. HYDROLOGY... A frontal boundary will stall across the Great Lakes with a subtropical airmass lifting into the region. Very moist conditions will hold through at least the weekend. This environment combined with passing low pressure systems and upper-level disturbances will bring several rounds of on and off heavy rain showers in addition to periods of embedded thunderstorms. Shower and thunderstorms will be likely today with best chances occuring this afternoon and evening. While storm total accumulations will be highly dependent on thunderstorm activity and where the frontal boundary over northern lower michigan sets up, the first opportunity for widespread heavy shower and embedded thunderstorm activity will be this afternoon into the evening with the passage of the first low pressure system. Additional rain activity, heavy at times, will continue Saturday into Sunday following the passage of the low pressure system. There is extremely high confidence that rainfall totals will reach or exceed 1.5 inches across most portions of SE MI by Sunday morning, with possible totals ranging somewhere between 2-4 inches. Localized higher rainfall amounts expected with thunderstorm activity. Impacts include rises on area rivers with the potential for flooding in urban and low-lying areas. An isolated to scattered risk for flash flooding will exist over all of SE MI with this set- up, also highlighted in WPCs Excessive Rainfall Forecast. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ UPDATE.......MR AVIATION.....99 DISCUSSION...CB MARINE.......TF HYDROLOGY....DRK You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
930 PM EDT Fri Jun 25 2021 .SYNOPSIS... High pressure will shift off the Atlantic coast this weekend into next week. This will bring moisture back to the region and a return of afternoon showers and thunderstorms through the end of next week. && .NEAR TERM /THROUGH SATURDAY/... As of 930 pm Friday: Regional radars depict the main Piedmont and coastal band of showers dissipating this evening, while spottier showers redevelop a bit farther west on outflows. Cannot rule out some isolated showers developing in the deepening moisture east of I- 77 late this evening and early overnight, with some mesoscale models showing isolated showers over the NC foothills and western Piedmont late tonight in weak upslope. Any rain showers will be isolated and light. Temperatures are falling a touch ahead of the forecast, but invading and lowering clouds from the east will halt the fall overnight and no mid-course corrections will be made on modifying minimum temperatures. Otherwise, the offshore ridge will retrograde slightly over the next 24 hours and this will restore more seasonable weather for the forecast area. Low-level flow will veer toward S and moisture flux will improve. The subsidence inversion will weaken, which along with warmer near-surface temps suggests diurnal convective chances will be better on Saturday afternoon compared to the past few days. Some of the mesoscale models, namely the HRRR and NAMNest, do indicate surprisingly little convective development during the aftn, seemingly a result of delayed warming due to the morning stratus. The NAMNest in particular tends to overdo surface moisture and these kinds of stratus events, so we`re not ready to totally buy that idea. Forecast PoPs are generally lower than our previous forecast, but still close to what would be expected climatologically. Max temps inch back almost to normal. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... As of 215 PM EDT Friday...Surface and mid level high pressure will be in place off the Mid-Atlantic coast for Sunday and Monday leading to easterly flow off the Atlantic and increased moisture. Despite the lack of forcing, expect showers and thunderstorms each afternoon and evening with the highest chance in the mountains. Temperatures through the period are expected to be near to just above climo. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... As of 215 PM EDT Friday...Ridging will remain in place along and off the Atlantic coast for next week. While the ridging may weaken some, a mid level trough and associated cold front dropping into the Great Lakes area looks to stay well to our northwest. Thus, our area will remain in the warm and moist air mass in place from this weekend. Mainly diurnal showers and thunderstorms are expected with the highest chance most days in the mountains. Highs will be near climo each day and lows slightly above climo each morning. In other words, a pretty typical summer pattern is expected next week. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: As diurnal cumulus/stratocumulus continue to slowly dissipate this evening, attention turns to the MVFR level clouds moving west from the Carolina Piedmont and the coastal plain. This activity will make slow progress toward the terminal forecast area and VFR conditions are expected for much of the night. MVFR to IFR bases will arrive in the easterly flow circa 08Z near KCLT and closer to 10Z/11Z at the Upstate TAF sites. Spotty showers will be possible as well in the Atlantic moisture, but with confidence too low to mention through Saturday morning. Anticipate very slow improvement to VFR bases by late morning and early afternoon on Saturday, but with scattered thunderstorm chances ramping up 18Z to 00Z. Winds will be light and some flavor of ENE to ESE early, becoming more southerly through the period. MVFR visibility in light fog is most likely overnight from KAVL to KHKY. Outlook: Deepening moisture will result in chances for afternoon and evening showers and thunderstorms through Wednesday. Mountain valley fog and low stratus will be possible each morning as well. Confidence Table... 01-07Z 07-13Z 13-19Z 19-00Z KCLT High 100% High 86% High 82% High 100% KGSP High 100% High 89% High 86% High 100% KAVL High 100% High 100% High 95% High 100% KHKY High 100% Med 72% High 84% High 100% KGMU High 100% High 89% High 80% High 100% KAND High 100% High 100% High 88% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SCW NEAR TERM...HG/JPT SHORT TERM...SCW LONG TERM...SCW AVIATION...HG/JPT
Area Forecast Discussion
National Weather Service Lincoln IL
857 PM CDT Fri Jun 25 2021 .SYNOPSIS... Issued at 646 PM CDT Fri Jun 25 2021 Thunderstorms will develop across central Illinois this evening...particularly along and north of a Shelbyville to Paris line where some of the storms could potentially produce damaging wind gusts and heavy rainfall. The storms will gradually diminish toward dawn Saturday. && .UPDATE... Issued at 857 PM CDT Fri Jun 25 2021 Thunderstorms continue to develop along an outflow boundary from central Missouri E/NE into central Illinois this evening. The storms are being aided by a 30-40kt 850mb jet oriented from the Ozarks northward into Illinois. 0150z/850pm radar imagery shows the strongest cells along a Bloomington line. Based on radar trends and latest HRRR forecast, think the line will gradually shift southward and will focus along the I-72 corridor for the next few hours. While overall severe threat will decrease as daytime instability wanes, attention will turn to potential flash flooding as training echoes drop locally heavy rainfall across that area. Most model guidance suggests the rainfall will slowly decrease in intensity after midnight as the precip becomes more scattered in nature toward dawn Saturday. Updated the forecast to better reflect PoP trends for the remainder of the night. && .SHORT TERM...(This evening through Saturday) ISSUED AT 343 PM CDT Fri Jun 25 2021 Surface analysis this afternoon depicts a stationary front stretched from northern IL into IA well north of the area. An outflow boundary is positioned across southeast IL into central MO with convection ongoing in our far southeast IL counties as well as new activity firing over central MO as of 3 PM. Elsewhere, a break from the precipitation is occurring with some breaks in the clouds noted across west-central portions of the state. SPC mesoanalysis depicts MLCAPE starting to build northward with clearing, though we remain capped (50-150 J/kg) from about I-70 northward from earlier convection. This will prevent anything from developing in these areas for the next few hours. Confidence in the evolution of activity going into tonight remains low. Once the CAP erodes, scattered storms should develop across west-central IL along the ouflow boundary sometime later this afternoon or early evening, which the 25.18Z HRRR picks up on. However, CAMs have not been performing well. The idea is that coverage will increase by tonight as a few mid-level waves ripple through the southwest flow aloft and the LLJ kicks in. Strong to severe storms remain possible across locations south of I-74 with damaging winds and large hail being the main threats. However, decent low- level shear with a boundary in the area could support a brief tornado or two. Additional rainfall amounts through Saturday morning look to range from 1-2" north of I-70, with higher amounts possible where storms train. With 1 to 3 hr flash flood guidance ranging from 1.5 to 2.5" due to recent soaking rains. Because of this, a Flash Flood Watch remains in effect for counties north of I-70 through Saturday morning. .LONG TERM...(Saturday night through Friday) ISSUED AT 343 PM CDT Fri Jun 25 2021 The upper-level pattern remains in a blocking regime this weekend and even into the new week, keeping periods of showers and storms possible. Shower and storm chances look to taper off Saturday morning as the LLJ recedes. Additional thunderstorm development looks likely along any remnant boundaries by the afternoon into evening hours of Saturday, pending how quickly the atmosphere destabilizes after overnight convection. A similar story going into Sunday with the same set up. All in all, additional rainfall amounts Saturday through Monday morning look to range from 1-3" north of I- 70. Shower and storm chances remain possible through a good portion of the week with the blocking pattern keeping southwest flow positioned over the local area. Let the NBM handle PoPs through the week for the time being. The pattern finally begins to change by the end of the week into next weekend as the ridging over the eastern CONUS/Atlantic breaks down. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 657 PM CDT Fri Jun 25 2021 Main aviation forecast concern will be timing of convection tonight. Scattered thunderstorms have developed across central Illinois early this evening, but these appear to be missing the terminals. Further upstream, more numerous cells across central/northern Missouri are spreading northeastward across the Mississippi River and will likely impact the TAF sites later this evening into the overnight hours. Based on radar trends and HRRR forecast, have included VCTS at KSPI after 02z...then further northeast to KCMI after 04z. Most models suggest the storms will diminish overnight, with only showers lingering across the area after 09z. As happened last night, forecast soundings show MVFR ceilings overnight into at least Saturday morning. It appears ceilings will improve to VFR at all sites except KPIA by midday. Winds will initially be S at around 10kt this evening, then will veer to S/SW and gust to around 25kt from late Saturday morning through the afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch until 7 AM CDT Saturday for ILZ027>031-036>038- 040>057-061. && $$ UPDATE...Barnes SYNOPSIS...Barnes SHORT TERM...NMB LONG TERM...NMB AVIATION...Barnes
Area Forecast Discussion...UPDATED
National Weather Service Portland OR
843 PM PDT Fri Jun 25 2021 Updated Aviation Discussion ...UNPRECEDENTED HEAT WAVE EXPECTED THIS WEEKEND INTO NEXT WEEK... .SYNOPSIS...An anomalously strong high pressure system aloft is beginning to build into the Pacific Northwest and will continue to do so this weekend, bringing a stretch of unusually hot weather to the region. The resulting heat is likely to break numerous high temperature records, with some all-time heat records in serious jeopardy. Coastal areas will be cooler, especially along the beaches. The hottest day overall appears to be Sunday, with only minimal cooling expected Monday - mainly for the coastal valleys and perhaps the Eugene/Corvallis area. The most extreme heat is expected to wane somewhat next week, but inland temperatures are still expected to be well above seasonal normals. && .SHORT TERM...Today through Monday...Perhaps the most intense heatwave for our region since the late 19th century - or at least close to it - is beginning to take shape across the Pacific Northwest as anomalously strong high pressure builds aloft. As of 2 PM, temperatures were generally running 5-10 deg F warmer than they were that time Thursday, with mid to upper 80s fairly widespread for the interior valleys. Latest (20z) HRRR analysis shows 850 mb temps running around +18 deg C at Salem, and this may be the last time they see 850 mb temps below +20 deg C until next Tuesday or Wednesday. While today is what would normally be considered a very warm to hot day for our inland valleys, Saturday appears to be roughly 10 deg F hotter as 850 mb temps climb through the lower 20s deg C. As such, latest (13z) NBM guidance shows an 80 percent chance of KPDX reaching 100 degrees Saturday afternoon, with 106 deg F favored by deterministic NBM guidance. For Salem, NBM guidance shows a 76% chance of reaching 100 degrees, with 104 deg F favored by deterministic NBM guidance. Given slightly lower values forecast by most MOS guidance, and the fact that 102 deg F is the monthly high temp record for PDX, we have hedged our forecast slightly below those numbers, but the difference in sensible weather will be minimal. The bottom line here is that triple-digit heat is expected to begin for most of our inland valleys Saturday, and will only intensify for Sunday. There has been a lot of (well-justified) hype lately regarding the high temperatures shown by many models (and the National Blend of Models) Sunday and Monday, with some showing all-time high temperature records being obliterated by 5 to 10 degrees. While models seem to be well in agreement of +28 deg C to +31 deg C for 850 mb temps during that period. The all-time record for 850 mb temperatures at KSLE per SPC sounding climatology is +28.3 deg C. So, just considering 850 mb temps, we would be in the ballpark of all-time record highs. But there are additional considerations. Recent model runs continue to show some easterly flow developing through the Columbia Gorge Sat night/Sunday which could potentially maximize the potential heat at the surface given the air mass aloft. For example, mixing down 850 mb temps of +30 deg C dry-adiabatically to the Willamette Valley floor would yield sfc temps of +43 to +45 deg C, or 109 to 115 degrees F. We are generally not forecasting temperatures that hot just yet, but 110 deg F certainly appears to be within reach for Portland, Salem, Vancouver, Hood River, and surrounding areas both Sunday and Monday. Models are suggesting a southerly wind reversal developing along the coast Sunday night and Monday, and they seem to be enhancing the strength of it. This may be good news for coastal valleys, especially Van Duzer Corridor southward. The 18z NAM appears potentially strong enough with a southwesterly marine push to keep Eugene in the 90s Monday while areas to the north continue to bake in triple digit heat. After nearing monthly heat records on Saturday and possibly all-time heat records on Sunday, temperatures will struggle to fall below 70 degrees in many areas at night. Downtown and inner eastside Portland will be slowest to cool each night, given their urban heat island effect. It is fathomable that some of these neighborhoods will fail to fall below 80 degrees for a 60 to 72-hour period between Saturday morning and Monday night. Unprecedented warm nights will offer little relief from the daytime heat, compounding the danger of heat-related illness for those without access to air conditioning. Areas outside of city centers will be relatively cooler, but even the cooler outlying areas will see lows mainly in the 60s and lower 70s Saturday night and again Sunday night. Even the mountains will be very warm at night, with areas along and above thermal belts stuck in the 70s or perhaps even lower to mid 80s for lows. In essence, the immediate coast will be the only outdoor place where people can truly escape the heat the next few days. Those stuck in inland areas without access to air conditioning are in real danger of heat-related illness, especially in Downtown Portland and the inner eastside of Portland. People in these areas should determine where cooling shelters are available in their area, or will likely need to be creative about finding ways to keep cool during this unprecedented heat wave. No changes to the existing Excessive Heat Warning. A Fire Weather Watch has been issued for the western slopes of the Washington Cascades, as well as the North Oregon Cascades and foothills, due to the easterly breezes expected there late Sat night through Mon morning. Weagle .LONG TERM...Tuesday through Friday...The long term forecast looks to be disappointing for anyone inland who is looking for substantive relief from the heat. The southwesterly marine push expected to cool off the coastal valleys Monday will likely become more prolific Monday night and Tuesday as 500 mb heights fall a bit, mainly due to an upper low lifting north across our offshore waters. This may even allow some low clouds into the coastal valleys Mon night and perhaps Tue night, along with more widespread "cooling" inland. The result will be much more pleasant temps for the coastal valleys Tue/Wed, while the inland valleys fall into the upper 80s to mid 90s for highs - still a good 10 to 20 degrees above late June/early July normals. Will need to watch the above-mentioned upper low closely, as any closer of an approach could bring the chance of isolated thunderstorms Mon/Tue. With the 12z ECMWF ensembles showing little chance of 500 mb heights lowering below the upper 5800 meter range for the remainder of the week, the marine layer will likely remain very shallow and thus temperatures will remain several degrees above normal for the foreseeable future. Weagle && .AVIATION...06Z TAF: A strong upper level high continues to strengthen over the Pacific Northwest this weekend. This is resulting in predominately VFR flight conditions under clear skies across the region. The exception to this will be along the coast. Guidance is suggesting that some IFR/LIFR conditions could develop along portions of the coast, with the greatest chance around KONP. At this time these lowered flight conditions will possibly develop starting around 06Z Saturday to 08Z Saturday, but chances of this happening are around 20-30% at this time. Confidence in IFR/LIFR conditions impacting KAST or KTMK are less than 20% at this time. Also, high density altitude hazards may manifest through the weekend as high temperatures are expected to range between 100-110 degrees for the interior lowlands and 90s for the Cascades and Coastal Ranges. For detailed regional Pac NW aviation weather information, go online to: KPDX AND APPROACHES...VFR under clear skies expected to continue over the next 24 hours. /42 && .MARINE...No immediate concerns as northerly flow will continue over the waters through at least Sunday afternoon. Flow will begin to change over the inner waters Sunday evening and Sunday night as a surface low develops offshore, resulting in a southerly wind reversal. Southerly winds should develop over the outer waters as well, most likely late Sunday night into Monday morning. Model guidance continues to support small craft level wind gusts around 25 kt Sunday night into Monday, but the probability of this occurring is between 50-60 percent. For the outer waters, longer fetch northwesterly winds may result in a building swell and steep seas to 8 feet. This may also warrant a Small Craft Advisory for late Tuesday and Tuesday night. -TK/JBonk && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Excessive Heat Warning from 10 AM Saturday to 11 PM PDT Monday for Cascade Foothills in Lane County-Cascades in Lane County-Central Coast Range of Western Oregon-Central Columbia River Gorge-Central Willamette Valley-Coast Range of Northwest Oregon-Greater Portland Metro Area-Lower Columbia-Northern Oregon Cascade Foothills-Northern Oregon Cascades-South Willamette Valley-Upper Hood River Valley- Western Columbia River Gorge. Fire Weather Watch from late Saturday night through Monday morning for Mt. Hood National Forest West of Cascade Crest- North Oregon Cascade Foothills. Excessive Heat Warning from 11 AM to 9 PM PDT Sunday for North Oregon Coast. WA...Excessive Heat Warning from 10 AM Saturday to 11 PM PDT Monday for Central Columbia River Gorge-Greater Vancouver Area-I- 5 Corridor in Cowlitz County-South Washington Cascade Foothills-South Washington Cascades-Western Columbia River Gorge-Willapa Hills. Fire Weather Watch from late Saturday night through Monday morning for Extreme South Washington Cascades and Foothills. Excessive Heat Warning from 11 AM to 9 PM PDT Sunday for South Washington Coast. PZ...None. && $$ Interact with us via social media:
National Weather Service Raleigh NC
955 PM EDT Fri Jun 25 2021 .SYNOPSIS... An inland penetrating coastal front will dissipate as it moves across central NC tonight. High pressure centered across the western Atlantic will extend into the middle Atlantic through the beginning of the workweek. A warm and humid southeasterly flow will develop across the Southeast. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 955 PM Friday... Evening surface analysis shows the westward advancing coastal front/surface trough moving across the U.S. route 1 area toward the western Piedmont. Dewpoints vary considerably across the boundary with TD`s in the lower 60s across the western Piedmont to the lower 70s across the eastern Piedmont. Not surprisingly, a stable air mass is in place west of the U.S. route 1 with MLCAPE values ranging around a few hundred across the far eastern Piedmont and Coastal Plain. Scattered showers and a few embedded storms earlier this evening driven by local forcing near the boundary has largely dissipated during the past couple of hours. However, convection has been more stubborn and even redeveloped across the coastal areas during the past two hours as a mid-level shear axis combined with weak instability is producing some scattered showers. These showers are entering Wayne and Johnston Counties this hour with more numerous showers toward Jacksonville and New Bern. Some high res guidance including the HRRR note that this scattered convection will persist and advance northwest over the next few hours. Expect a lull a little after midnight with scattered convection redeveloping across the Coast toward daybreak with some patchy rain possible in the western Piedmont. otherwise, partly to mostly cloudy skies will given way to widespread stratus overnight. Lows will range in the mid 60s across the drier western Piedmont to around 70 in the eastern Piedmont and Coastal Plain. -Blaes && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... As of 335 PM Friday... A front moving in from the Atlantic coast is the main focus for rain today, however with the front decaying over the next few hours, there will not be a particular focus for showers and thunderstorms tomorrow. As a result, have stuck with just chance pops across the forecast area along a diurnal cycle, although higher chances remain across eastern counties with greater moisture present. Cloud cover should also not be quite as thick as today, which should allow high temperatures to be more uniform, even if the values are still below normal, in the mid 80s. Low temperatures will not change too much from tonight, with values in the upper 60s. && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 320 PM Friday... The upper ridge offshore will gradually strengthen and migrate southward toward Bermuda next week, resulting in a period of slightly above normal temperatures along with a chance of diurnally driven/weakly forced convection. Sunday will start off with a 592dm upper ridge off the Delmarva coast with weak dry advection in the mid levels across NC. PW`s, while still above normal, will gradually fall from 1.9 inches in the morning to nearly 1.4 inches by late afternoon. Any convection that develops along the sea breeze and moves inland should dissipate quickly given increasing subsidence, dry air aloft, and 5-10 kts of deep layer shear and it would seem that 15-20 PoPs across the Coastal Plain should capture things appropriately. Monday will see a similar scenario play out as the upper ridge moves even farther south (while strengthening) with little in the way of synoptic support for long lived convection. GFS/EC suggest a weak inverted wave and plume of moisture will move into the southern part of NC late Monday but this feature should be far enough south to be of minimal concern. Tuesday through Thursday will see southeasterly flow take hold over the area, with steadily increasing amounts of deep moisture advected into the Piedmont. Scattered afternoon showers and storms, with a focus across the Coastal Plain where afternoon instability will be maximized up to 300-500 J/kG, should be a recurring theme each day. Meanwhile across the northern Plains, a deepening upper low and associated surface cold front will slowly make its way toward the Appalachians during the week and will eventually move through the area. Not surprisingly, the timing of this front continues to slow down given the strength and position of the offshore ridge and the closed off nature of the low. Until the upper ridge can weaken sufficiently or migrate away from the area, the cold frontal passage will be delayed. Diurnally driven convection will once again be favored on Friday, with at least some emphasis near the mountains in addition to the Coastal Plain as increased moisture is drawn northward ahead of the approaching front. As for temperatures, highs in the lower 90s along with lows in the low 70s will be common area-wide. A very climo-like pattern. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 815 PM Friday... An inland advancing coastal front will advance across the Piedmont this evening and begin to dissipate overnight. Scattered showers and thunderstorms near the boundary this afternoon will continue to dissipate and become less numerous. Outside of lingering showers, most locations across central NC will have VFR conditions this evening with areas of stratus and CIGS around 4-6kft. Overnight, expect widespread low MVFR stratus to develop after midnight with CIGs falling into the IFR range by 7 to 11Z with areas of MVFR fog as well. The stratus will slowly lift on Saturday with VFR conditions in most locations by midday before another round of scattered showers and storms develop on Saturday afternoon. Light northeast to easterly winds less than 7kts are expected overnight with light southerly winds on Saturday. Outlook: Scattered showers and storms on Saturday afternoon will dissipate on Saturday evening. Expect late night and daybreak stratus and fog from Sunday morning through mid week. Chances of afternoon and evening storms will be more limited on Sunday through Monday with increasing chances on Tuesday through Wednesday. -Blaes && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Blaes NEAR TERM...Blaes SHORT TERM...Green LONG TERM...DL AVIATION...Blaes
Area Forecast Discussion
National Weather Service Riverton WY
407 PM MDT Fri Jun 25 2021 .SHORT TERM...This evening through Saturday night Issued at 311 PM MDT Fri Jun 25 2021 Great precipitation event for many areas the past 24 hours across western and central Wyoming, along with much cooler temperatures and breezy north wind. Areas from the Lander Foothills eastward to Natrona County picked up between half and one inch, with a couple of reports over an inch around Casper. The primary area of stratiform rain has moved to southeast WY this afternoon as the trough axis also moves SE. Unstable moist northerly flow follows the trough, with scattered showers and thunderstorms developing just after 10am this morning, mainly over the mountains and southwest WY. So far, high resolution models are doing a good job of highlighting the initiation and transport areas, which are over the mountains and to the SSE over the foothills and basins. The storms today are not expected to be severe, although the slightly stronger ones should produce brief heavy rain with some small hail and frequent lightning. Outflow winds over 30 mph are also possible. Most of the convective activity should end around sunset, though the HRRR and GFS are suggesting some enhanced activity across central WY from sunset through about 3am. Temperatures today are mostly well below normal for late June, which is a nice reprieve from the heat of last week. With the trough axis moving to western NE into eastern CO overnight, and the large ridge over the Pacific Northwest developing, WY will stay in cool northerly flow on Saturday. The nose of a strong jet will also be pushing southward into WY. As a result, Saturday will see stronger northerly flow over the area, continued cool temps, and more scattered showers with isolated thunderstorms. The convective activity is expected to primarily be along and east of the continental divide. More widespread storminess should occur over the Bighorns and Johnson and Natrona Counties. Areas near the Bighorns could see amounts around 0.25" with the stronger storms. The showers and storms should diminish between 6 and 8 pm Saturday evening. The surface pressure gradient also adjust for more of a east-northeast surface flow Saturday night into Sunday morning with the cool air continuing to be banked up in eastern and central WY. Southwest WY will be treated to cool easterly flow Saturday evening. .LONG TERM...Sunday through Friday Issued at 311 PM MDT Fri Jun 25 2021 North flow will dominate much of the long term forecast as a persistent high rotates off the northwest CONUS and a trough stays to our east. Sunday will remain cool, and with some upper jet energy across eastern Wyoming there will likely be another round of scattered showers and thunderstorms east of the Divide. The best chance Sunday appears to be across Johnson and Natrona counties where the best upper level support will be realized. A warming trend will begin Monday, with only isolated activity looking likely again across eastern areas. Tuesday through the end of the week will be warmer as the high builds east toward the area. Most of the area will remain dry, although isolated convection is possible during the afternoons. The warming temperatures may be the main story next week, as well above normal highs look to return to the area by Wednesday. && .AVIATION...For the 00Z TAFS through 00Z Sunday Scattered showers and thunderstorms will continue this evening, gradually decreasing through around 06Z. Mainly VFR conditions are expected, but local MVFR ceilings will be possible with heavier activity including around any thunderstorms. Isolated shower and thunderstorm activity is again expected late Saturday morning and afternoon. A gusty north wind is expected at KRKS and terminals east of the Divide Saturday afternoon, gusting 25 to 30+ kts at times. && .FIRE WEATHER... Issued AT 311 PM MDT Fri Jun 25 2021 A cool moist flow pattern has established over western and central WY with some areas receiving significant precipitation over the past 24 hours. Scattered showers and thunderstorms will continue this afternoon into the evening hours. The storms will produce brief heavy rain, frequent lightning, and gusty outflow over 30 mph. The storms are primarily forming along and to the SE of mountains and moving to the SSE. They will mostly dissipate by sunset, though there is a chance of continued showers and thunderstorms over central WY overnight. Humidities will again recover quite nicely overnight with light to breezy north wind. Saturday will again see scattered showers with isolated thunderstorms with cool north wind. The storms Saturday will mostly be along and east of the divide, with more widespread storms over Johnson and Natrona Counties. Temperatures will again be below normal, though warming somewhat across western WY. Cool conditions continue Sunday with a general east wind, with warming and drying from the northwest starting on Monday. && .RIW WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...McDonald LONG TERM...Myers AVIATION...Myers FIRE WEATHER...McDonald
Area Forecast Discussion
National Weather Service San Angelo TX
602 PM CDT Fri Jun 25 2021 ...New AVIATION... .SHORT TERM... (This evening through Saturday) Issued at 148 PM CDT Fri Jun 25 2021 Showers and thunderstorms are forecast to develop along the dryline this evening across the South Plains/northern Permian Basin. Most of this activity is forecast to dissipate before moving into our forecast area, but a few storms could approach our northwest counties late this evening. Otherwise expect mainly dry conditions overnight. Low temperatures will be in the low to mid 70s. Expect south winds of 10 to 15 mph to remain gusty through the overnight period. On Saturday, another hot day is forecast, with highs in the mid to upper 90s. By late afternoon, a cold front will move into north Texas while a dryline sharpens across the Trans-Pecos region. Isolated to scattered showers and thunderstorms are forecast to develop to our west, along the dryline, with additional storms developing along the cold front. Most of this activity should remain north and west of the area through tomorrow afternoon, with better rain chances during the evening hours. A few storms could approach our western/northern counties late in the afternoon, so have continued slight chance/chance PoPs for these areas. A few strong to severe thunderstorms will be possible, with large hail and damaging winds being the main hazards. && .LONG TERM... (Saturday night through next Friday) Issued at 210 PM CDT Fri Jun 25 2021 A well-advertised pattern change looks to set in starting Saturday night and continuing through much of next week. After weeks of large-scale ridging, a trough will set up over the northern Plains and put much of the south-central US in southwest flow aloft. As this feature develops, a cold front will push southward through the Panhandle and stall over northwest Texas by Sunday morning. An axis of moisture with PWATs of 1.5-2.0 inches will likely set up over northwest Texas on Sunday, which should increase rain chances across western portions of the Big Country. As we get into Monday, a weak upper low over south Texas will merge with the northern Plains trough. This should bring more moisture in from the gulf, allowing PWATs to climb above 1.5 inches area-wide. Cloud-cover will increase significantly, along with chances for rain on Monday through Tuesday. High temperatures will be held down to the low to mid 80s during this time due to persistent cloud cover and rain chances. While rain chances will be higher these days, it is important to remember that the amounts will still be fairly low. For the second half of next week, the upper-level trough will elongate and and shift slightly eastward over the Upper Midwest and Great Lakes. But the base of the trough will still be over northern and western Texas. So while rain chances will decrease slightly, we are still looking at a continuing cloudy pattern with temperatures below normal. && .AVIATION... (00Z TAFS) Issued at 558 PM CDT Fri Jun 25 2021 Convection continues much farther west across the Permian Basin, but latest models like the HRRR show these storms dissipating before reaching near any of the terminal locations. Will leave dry for now and watch radar. Otherwise, VFR conditions this evening and into the overnight hours once again. MVFR cigs will redevelop later tonight across the southern terminals and may approach KSJT shortly after sunrise. Low clouds break up and lift by late morning and leave VFR conditions. Gusty south winds will continue tonight and through Saturday afternoon. && .PRELIMINARY POINT TEMPS/POPS... Abilene 74 95 70 85 / 5 10 50 50 San Angelo 73 98 71 92 / 5 5 30 30 Junction 73 95 71 92 / 0 0 5 20 Brownwood 73 95 72 90 / 0 0 20 30 Sweetwater 74 94 68 82 / 10 20 60 50 Ozona 73 94 70 90 / 5 5 20 20 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Daniels LONG TERM....SK AVIATION...07
Area Forecast Discussion
National Weather Service Tulsa OK
955 PM CDT Fri Jun 25 2021 ...UPDATE... .DISCUSSION... Currently watching two convective systems approaching the forecast area, albeit slowly, one about a county to the north across southern Kansas and another in western Oklahoma. Regarding the Kansas system, although it is likely that it will affect at least the northern tier of counties in northeast Oklahoma late this evening or early tomorrow morning, there remains uncertainty as to how far south it moves into the forecast area before it decays. One thing to note, with as slow as this system`s movement is, if it doesn`t diminish as quickly as expected, heavy rain and flooding would become a problem sooner rather than later. The western system appears more likely to affect a bigger chunk of northeast Oklahoma toward and after midnight. Instability remains high across much of the area, but wind shear is notably less than locations to the west. As such, while an isolated severe storm will remain possible, the expectation of organized severe weather continues to be low. Notable changes to the going forecast were to adjust POPs largely for increased timing specificity but also to reduce them some in northwest Arkansas, to increase forecast rainfall after midnight along the Kansas border, and also to decrease low temperatures slightly across parts of northeast Oklahoma. && .PREV DISCUSSION... /Issued 627 PM CDT Fri Jun 25 2021/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. Convection over ern TX Panhandle/wrn OK expected to develop eastward this evening, with impacts expected at nern OK sites after 06z. Included wind gusts to 35 kt and MVFR cigs/vsbys with that activity. Low clouds again expected across nwrn AR sites late tonight, with a chance the convection affects XNA/ROG/FYV after 12z. MLC/FSM likely remain VFR, and south of any thunderstorm activity through this forecast period. Multiple rounds of convection possible this forecast period nern OK sites, and timing is problematic, but most likely redevelopment in afternoon along frontal boundary that is expected to sag into the area. PREV DISCUSSION... /Issued 306 PM CDT Fri Jun 25 2021/ DISCUSSION... Showers and thunderstorms have developed near a frontal boundary across Kansas this afternoon. This activity is expected to continue to organize, and begin to push southeast towards and into our area later this evening and overnight. The latest HRRR is quite aggressive with the southward progression overnight, and certainly cannot rule this out. For now, will keep the higher pops confined to northeast Oklahoma, with lower pops as far south as McAlester and Fort Smith. Early day convection will gradually wane by midday Saturday, with renewed development expected by late afternoon along the frontal boundary, which by that time should be near the northwest part of our area. Locally heavy rainfall amounts will be more likely Saturday evening, so a flood watch may be needed by that time, especially if significant rainfall occurs tonight. The frontal boundary will likely sag very slowly south with time, as an upper trough remains in place just to our west. This will keep shower and thunderstorm chances going through much of next week, with the potential for locally heavy rainfall. The trend will be for the heavier rainfall to slowly shift to the south and east with time. With all the clouds and rain, high temperatures will be several degrees below normal for most of the next week. Stayed close to the National Blend of Models forecast. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...22