Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/18/20

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
536 PM MDT Wed Jun 17 2020 .AVIATION... 00Z TAF CYCLE Upper trough moving through the Great Basin with sw-wly flow aloft over NM. At 23Z dryline starting to push back wwd with isold convection possible along the boundary before 02Z. Short term models indicate the dryline may reach as far west as the Pecos Valley by 06Z. Sfc lee trough to shift ewd with nly wind shift over ne NM aft 10Z. Areas of MVFR vsbys/cigs in FU/HZ are possible over portions of wrn and central NM between 06Z-16Z. && .PREV DISCUSSION...230 PM MDT Wed Jun 17 2020... .SYNOPSIS... The closed low over eastern Idaho and the trough associated with it will lift slowly northeast through Thursday. Another weaker trough will impact NM Friday. A back door cold front will push south and west across the east Thursday night into Friday, resulting in a cooler day across the east Friday afternoon. Some showers and storms will be possible during this time, mostly in the northeast. Wind shifts each day and night in the northeast will keep this area as a focus for a few showers and thunderstorms this weekend into next week. The strongest wind shift/backdoor cold front/dry line will be next Monday night in the east. Enhanced convection is expected in the northeast Tuesday and much of the east Wednesday. && .DISCUSSION... SHORT TERM...(WEDNESDAY NIGHT THROUGH THURSDAY NIGHT}... Dry southwest flow has strengthened this afternoon with gusts ranging from 25 to 50mph across much of western and central NM. Active fire plumes in AZ are starting to build this hour and their strengths and trajectories will be closely monitored tonight as southwesterly to westerly flow brings them into west-central NM late this evening and throughout central NM by Thursday morning. The big question is just how much smoke settles to the surface overnight. Have included mention of smoke in the forecast across a good portion of western and central NM overnight into Thursday morning before mixing out by mid-day. HRRR near-sfc smoke model is depicting a repeat situation for Thursday night into Friday morning, which makes sense given the continued WSW flow from AZ into NM. Elsewhere, there is some cu over the lower Pecos River Valley over DeBaca and Chaves Counties this afternoon. These could produce a few high-based showers this afternoon resulting in some erratic gusty winds from Roswell to Fort Sumner. The only chance for stronger storms lays along the TX border from I-40 southward through Curry and Roosevelt Counties. There remains a marginal risk for a few of these storms becoming severe, but these storms will quickly move east into Texas. Meanwhile, an embedded shortwave within a larger troughing pattern over the western CONUS will eject over the Northern Great Plains tonight with relaxing southwest flow resulting through NM Thursday. This will bring down winds a notch for Thursday and also send down a backdoor cold front along the front range of the Rockies. This backdoor front enters northeastern NM Thursday with a chance for some showers, and more likely a low stratus deck over northeastern NM heading into Friday morning and the Long Term period. 24 LONG TERM...(FRIDAY THROUGH WEDNESDAY)... Behind the cold front from Thursday night, Friday will be cooler in the east. Showers and thunderstorms are forecast from the Sangre de Cristo Mountains to the east central plains, the most widespread in the northeast. This convection will continue into Friday night. The weekend and next Monday will be drier and warmer, with the only convection in the far northeast each afternoon. Another back door cold front will impact eastern NM Monday night with slightly cooler weather for Tuesday and Wednesday. Showers and thunderstorms will be more widespread Tuesday in the northeast and from the central mountains to east central NM Wednesday. 40 && .FIRE WEATHER... Critical fire weather conditions will remain over west-central and northeastern NM through the rest of this afternoon as stronger southwest winds have mixed down the surface. Peak gusts of 25 to 45 mph will result combining with MinRHs dipping to the single-digits in some spots. Smoke plumes from active fires in AZ will need to be closely monitored through tonight into Thu morning as this smoke has the potential to settle over a good portion of western and central NM. SW to W flow remains over NM Thu, but to a lesser degree. This will keep western and central NM in play for another round of smoke concerns heading into Fri morning. Low-level moisture sets up further east Thu morning allowing for more widespread poor recoveries tonight. The exception will be behind a backdoor front entering far northeastern NM Thu morning, pushing to the central mountain chain Fri morning. This will bring better overnight recoveries across the east and a chance for showers/storms through northeastern NM along and east of the Sangre de Cristo Mountains. Transport winds shift W then NW this weekend with the dryline swashing back and forth through the eastern plains each night. This should reduce smoke concerns for the weekend heading into next week. Winds will remain the limiting factor for any critical fire weather conditions during this time. 24 && .ABQ WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM MDT this evening for the following zones... NMZ103>105. && $$
Area Forecast Discussion
National Weather Service La Crosse WI
1058 PM CDT Wed Jun 17 2020 .SHORT TERM...(This evening through Thursday) Issued at 225 PM CDT Wed Jun 17 2020 Tonight, low temperatures will cool into the 60s, but another pleasant day is on tap. Tomorrow afternoon, temperatures will climb back into the upper 80s. Dew points will remain nearly steady around the lower 60s and upper 50s. Cloud cover will be on the increase tomorrow afternoon ahead of the incoming cold front and associated precipitation. Depending on the rate of progression of both the upper level short wave and associated surface cold front, shower and storm chances begin increasing late Thursday afternoon around 00z. In general, a band of shower/storms is expected to slowly track eastward across the region overnight Thursday into Friday morning. There could be a few strong storms, but the severe risk is low at this time. There is some instability to work with Thursday evening, but the deep layer shear looks to remain off to the west farther behind the surface front. Widespread flooding potential appears low as these past few days have been dry. Local heavy rain is possible with the stronger, pulse type storms and precipitable water values ranging from 1.5" up to 2.0". .LONG TERM...(Thursday night through Wednesday) Issued at 225 PM CDT Wed Jun 17 2020 For Friday, a few lingering showers from overnight could last into the afternoon hours. High temperatures will be around 10 degrees cooler than Thursday. By the evening, the front will be further off to the east. Another shortwave trough coming out of the southern plains heading northeast nearly along the remains of that surface frontal boundary will bring additional chances for showers and storms over the weekend. Over the first half of the work week, a nearly stacked low looks to wrap up and slide over southeastern Ontario into the Great Lakes region. With the area under northwesterly flow, small chances for precipitation are introduced as pieces of short wave energy pass through this wave pattern. && .AVIATION...(For the 06Z TAFS through 06Z Thursday night) Issued at 1058 PM CDT Wed Jun 17 2020 Relatively quiet VFR conditions are expected through Thursday afternoon. A cold front will be approaching from the west and with a tight pressure gradient ahead of this front, look for gusty south winds for much of the day at both sites. The front looks to be close enough to produce a mid to high level VFR ceiling at both sites Thursday evening with some convection expected to be near KRST. The 18.00Z NAM has come in with a bit slower solution holding any rain off until mid-evening and the latest runs of the HRRR are also trending toward a slower solution or having the leading activity breaking up as it initially comes in. With this uncertainty, will only add a VCSH to KRST for now. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Peters LONG TERM...Peters AVIATION...04
Area Forecast Discussion
National Weather Service Bismarck ND
1102 PM CDT Wed Jun 17 2020 .UPDATE... Issued at 1100 PM CDT Wed Jun 17 2020 We will leave Dickey county in the watch through Midnight. Otherwise will cancel Lamoure. UPDATE Issued at 817 PM CDT Wed Jun 17 2020 The surface trough and associated low pressure system across eastern North Dakota has moved slowly east. The line of convection now looks like it will remain east of most if the Jame River Valley. So we will cancel most of the severe thunderstorm watch except for Dickey and Lamoure counties. A thunderstorm or two could clip the far eastern portion of these counties this evening. Otherwise, most of west and central North Dakota was mostly clear, while the showers across Montana were slower than forecast to move east into western North Dakota. The mid level water vapor loops show a circulation across southwest Wyoming that will move northeast tonight. This feature, in the relatively fast southwest flow aloft will bring some mid level vertical motion across central South Dakota this evening, which will move northeast into North Dakota later tonight. We expect further showers and thunderstorms to develop and move north into south central North Dakota late tonight, This is not expected to be severe, but may spread showers and a few thunderstorms into the south. So we cleared the precip over much of the west and central this evening, then brought chances back in later tonight, mainly south central, east of Bismarck. UPDATE Issued at 521 PM CDT Wed Jun 17 2020 This update for Severe Thunderstorm watch 282 until 11 pm CDT. && .SHORT TERM...(This evening through Thursday) Issued at 249 PM CDT Wed Jun 17 2020 Severe thunderstorm potential in parts of south central ND into the James River valley is our focus through this evening. As of 19 UTC, a nearly stationary frontal zone extends from near Linton to Carrington. Elevated convection continues near and to the cool side of the boundary, with low-level theta-e advection ongoing in the moist sector where surface dewpoints have risen into the middle and upper 60s F. Steep midlevel lapse rates are contributing to moderate to strong instability with MLCAPE from 2000-3000 J/kg, and model simulations and RAP objective analysis data suggests MLCIN is quickly becoming minimized with boundary layer heating and moistening. Forecast soundings are strongly in agreement that a warm nose near 700 mb will persist until close to 00 UTC, which along with initially weak confluence along the stationary boundary casts some doubt on the timing of surface- based convective initiation. In contrast, low-level water vapor imagery has been showing a subtle midlevel impulse embedded in southwest flow aloft that is approaching central SD, and recent visible satellite imagery reveals subtle cirrus associated with this impulse near Phillip, SD, as of 1930 UTC. Extrapolation of this feature and in particular its associated cirrus -- which likely reflects ascent and cooling aloft required for convective initiation -- has it reaching the frontal zone in south central ND between 2130 and 2230 UTC. Shallow cumulus near the deeper moist layer near the frontal zone and the elevated convection in its vicinity are contributing to notable differential heating and the augmentation of the low-level ascent and the approach of the aforementioned impulse aloft is increasing our confidence in the initiation of surface-based thunderstorms initially near an axis from Linton and Napoleon toward Carrington around 22 UTC. Some uncertainty remains in the timing of convective initiation given the lingering warm nose aloft in forecast soundings and a disparate set of solutions from CAMs, including the HRRR, which has held off initiation until closer to 00 UTC and mainly east of our forecast area. However, that`s a known bias of the HRRR, and our confidence in the timing and evolution is increasing as the previously-mentioned observational trends come in focus. Once storms develop, they will be propagating in an environment characterized by effective shear on the order of 30-40 kt, which supports both organized multicells and potential supercells with the magnitude of instability present. Given a modest orthogonal component of deep-layer shear vectors to the frontal zone, some initially-discrete supercell modes are possible, though weaker high-level flow and right-moving supercell motion vectors from ~230 degrees -- closer to the orientation of the boundary -- do suggest messy modes could evolve in time. Still, the CAPE-shear setting and steep lapse rates continue to support advertising hail up to golf ball size, further advocated by analysis of SPC SARS output. Some explicit sounding analog matches do show potential for larger hailstone sizes given the large instability and high inflow-layer theta-e, but the potential for messy modes means we are not advertising that at this juncture. We will also continue to message damaging wind gusts up to 70 mph. There is a non-zero tornado risk given 0-1-km SRH increasing to between 100 and 150 m2/s2 in the James River valley by early evening, but we have refrained from explicitly mentioning that at this time with- out stronger deep-layer shear and marginally-favorable MLLCL heights, along with potential for messy storm modes. Based on HREF-SREF blended severe-storm timing guidance, we feel that the risk of severe thunderstorms will subside by 06 UTC. Otherwise, the larger middle- and upper-level trough is forecast to lift northeast into southern Canada by Thursday as it evolves into a slow-moving low aloft. A jet core and embedded shortwave trough rotating around that feature could bring another round of showers and a few thunderstorms to south central areas overnight and early Thursday morning. Ultimately, this evolution will also drive another cold frontal zone eastward by Thursday and that is forecast to lead to a breezy day. We weighted the forecast toward the higher, MOS-based wind guidance on Thursday. A cyclonic flow regime could yield low-topped convection, but we relegated PoPs mainly to southwestern ND where forecast soundings suggest less influence from a midlevel subsidence inversion than elsewhere during the day. .LONG TERM...(Thursday night through Wednesday) Issued at 249 PM CDT Wed Jun 17 2020 We will be in a seasonable, albeit slightly cooler pattern on the whole through the long term, with a few chances of showers and thunderstorms, mainly this weekend. On Thursday night, the 12 UTC model suite is consistent showing a strong surface high moving through the Northern High Plains, with light winds and a subsidence regime supportive of lows likely in the 35 to 40 F range in parts of southwestern ND. We will need to consider the potential for frost in this setup. Thereafter, the upper-level low in southern Canada will slowly be shifting eastward amid synoptic-scale blocking. The cyclonic flow on the southern flank of the low and potential impulses embedded in it will bring some chance of showers and storms this weekend, with a slow drying trend early next week. The 12 UTC ECMWF and GFS suggest a non-zero risk of stronger storms Saturday, though the 00 UTC GEFS-based CIPS analog severe probabilities suggest relatively low confidence in that. The overall flow may become less cyclonic by early next week, leading to lower precipitation probabilities in ensemble guidance. Highs through the period will generally be in the 70s to lower 80s F. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 817 PM CDT Wed Jun 17 2020 Hazards to aviation tonight include thunderstorms across south central North Dakota. Also MVFR conditions are expected to develop across the western and northern North Dakota late tonight and Thursday associated with a cold front. At 8 PM CDT, the cold front extended across southern Canada. The front will move southeast and bring some MVFR ceilings into the region late tonight and Thursday. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...WAA SHORT TERM...CJS LONG TERM...CJS AVIATION...WAA
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
921 PM CDT Wed Jun 17 2020 .UPDATE... Storms that developed over the Trans Pecos earlier this afternoon have been able to hold together and currently tracking southeastward along the Rio Grande, with majority of the convection on the Mexican side of the border. Based off of current radar trends, went ahead and included a mention of thunder for our far western areas along the Rio Grande. Also within the past half hour, an isolated cell has developed over Crystal City. This storm has had hints of possible small hail and frequent lightning. Sounding from DRT this evening shows fairly steep mid level lapse rates for June ~ 7 C/km. High res guidance is still out to lunch on this activity, so current thinking is this activity should dwindle with most of it staying on the other side of the border over the next hour or two. && PREV DISCUSSION... /ISSUED 624 PM CDT Wed Jun 17 2020/ AVIATION... All sites VFR through the remainder of the the evening. Complex of storms NW of Del Rio should dissipate before reaching DRT but the latest HRRR run shows some activity could persist. Will have to monitor, no mention of thunder in for now. MVFR ceilings develop across all sites tonight and scattered out late Thursday morning. Southeast winds should remain at or below 12 knots tomorrow. VFR will prevail through the remainder of the period. PREV DISCUSSION... /ISSUED 247 PM CDT Wed Jun 17 2020/ SHORT TERM (Tonight through Thursday Night)... Extensive cumulus field over the western half of South Central Texas today, but less convection than the last couple of days showing the upper ridge has strengthened. We don`t expect much change in the pattern during this period. The upper ridge will tilt a bit to the east, but remain in place over Texas. The low level flow will continue to be from the southeast keeping moist air in place. There is some model disagreement about convection. Most of the models are dry, but the GFS continues to produce showers during the daytime hours Thursday. We have gone with the consensus dry forecast through this period. We have also gone a couple of degrees above the model blend on high temperatures Thursday since it has consistently underperformed with it`s cooler forecast. Low temperatures both tonight and Thursday night will be near seasonal normals. LONG TERM (Friday through Wednesday)... Friday continues the pattern of weak upper ridging to offset localized moisture pooling. Thus another day of a few showers and very isolated storms favors areas around San Antonio metro and areas to the SE toward the Coastal Bend where low level moisture convergence appears to focus. By Saturday 500 mb heights fall to form a weak trough over Central TX while low level moisture continues to funnel north from the Gulf. There could be some pockets of more organized storm clusters moving inland, particularly over the Coastal Prairies. Upstream NW flow continues a weak troughing pattern to leave a very similar picture for rain chances on Sunday. The NW flow pattern only shows up in the 500 mb winds, so will not show any interest in nighttime rain chances for Saturday night or Sunday night for now. By Monday morning mid-level subsidence begins to build over West TX and nudges the isolated PoP areas eastward, and the middle of next week is trending more and more stable. The re-establishment of high pressure aloft should also lead to hotter temperatures for the work week, and without a significant change in low level winds expected, higher heat index values as well. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 73 93 72 93 72 / 0 - 0 20 - Austin Bergstrom Intl Airport 70 93 72 93 71 / 0 - 0 20 - New Braunfels Muni Airport 72 92 72 92 71 / 0 - - 20 - Burnet Muni Airport 71 91 71 91 70 / 0 - 0 10 - Del Rio Intl Airport 76 97 75 97 75 / 20 10 10 10 10 Georgetown Muni Airport 72 94 72 93 71 / 0 - 0 10 - Hondo Muni Airport 74 93 72 94 72 / 10 10 10 20 10 San Marcos Muni Airport 72 93 71 93 70 / 0 - - 20 - La Grange - Fayette Regional 72 94 72 93 71 / 0 - 0 20 - San Antonio Intl Airport 74 92 74 92 74 / - 10 10 20 10 Stinson Muni Airport 74 91 74 92 74 / - 10 - 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term/Aviation...EWilliams Long-Term...Platt
Area Forecast Discussion
National Weather Service North Platte NE
624 PM CDT Wed Jun 17 2020 .SYNOPSIS... Issued at 312 PM CDT Wed Jun 17 2020 A very amplified H5 pattern was noted across the CONUS this morning. Closed low pressure remained entrenched over the Carolinas with a trough extending south into Florida. High pressure was located north of the low over Lake Huron and southern Ontario. Further west. a closed low was located over eastern Idaho with a trough extending to the southwest into northern Nevada. A broad shield of cloud cover extended north and northeast of the low into western Wyoming, Montana and Idaho. At the surface, a stationary front was oriented from northeastern North Dakota, south into central South Dakota and the Panhandle of Nebraska. A dryline has developed over eastern Colorado over the past couple of hours and was oriented from just east of Holyoke Colorado, south along the KS/CO border. East of the frontal boundary, winds were southerly across western and north central Nebraska this afternoon and temperatures were generally in the lower to mid 90s. && .SHORT TERM...(This evening through Thursday night) Issued at 312 PM CDT Wed Jun 17 2020 The main forecast challenge in the near term is thunderstorm and severe chances tonight. By 4 PM CT, the before mentioned dry line will surge to the east and northeast into far SW Nebraska. This dryline bulge, forecast to be INVOF Perkins, Keith and western Lincoln county at 4 PM CT is expected to be the focal point for thunderstorm initiation late this afternoon. The latest NAM12 soln, NAM Nest and several recent runs of the HRRR initiate convection in this three county area around 5 PM CT this evening. Felt confident enough in this forecast, to drop pcpn chances further south into far SW Nebraska with the previous forecast update. Once storms do develop, they will track quickly north northeasterly given the current fcst H5 winds. As storms track to the north northeast into the Sandhills and north central Nebraska, they will encounter better moisture and increasing deep layer shear as they traverse north, leading to an increased threat for severe storms. As for severe mode tonight, strong winds appear to be the main threat given the inverted V type soundings. Marginally severe hail appears possible but very large hail not, given the very high freezing levels. The cold front track across central portions of the forecast area by late evening, clearing the forecast area Thursday morning. The threat for showers and thunderstorms will continue into the overnight, mainly over north central into northeastern portions of the forecast area. Some showers may linger Thursday morning in the eastern forecast area INVOF the exiting front. The frontal boundary will then stall just off to the east of the forecast area for Thursday. Inherited forecast had a mention of tsras in the far eastern forecast area Thursday afternoon/early evening and couldn`t rule this out given the latest NAM12/GFS soln. Feel the threat for showers and thunderstorms, will shift east of the forecast area after sunset Thursday evening. .LONG TERM...(Friday through Wednesday) Issued at 312 PM CDT Wed Jun 17 2020 Surface high pressure will build into the Dakotas and northern Nebraska Friday. South of this feature, easterly winds will develop, leading to upslope conditions and cooler temps across the forecast area. With expected clouds and easterly winds, temperatures will struggle to get out of the 70s Friday. Late Friday, an upper level trough will lift into the central Rockies. Downstream of this feature, showers and thunderstorms are expected to develop along the front ranges of Colorado and Wyoming and over the western Nebraska Panhandle. This will be in the vicinity of a surface boundary and weak theta E ridging in these areas. Better chances for more widespread rain will arrive Friday night into Saturday morning as the trough aloft enters the front range Friday night, emerging into western Nebraska Saturday morning. This activity will then shift east of the area Saturday afternoon into Saturday evening. For Sunday and beyond, northwesterly flow will develop aloft as upper level low pressure intensifies over the upper Great Lakes and southeastern Canada. Temperatures in this flow regime will be seasonal with highs in the middle to upper 80s. Precipitation chances will be limited in this flow regime with mainly dry conditions expected. Beyond Wednesday, early indications are that ridging will build east of the Rockies late next week, leading to the development of hot and dry conditions. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 623 PM CDT Wed Jun 17 2020 For the KLBF terminal: Expect VFR conditions over the next 24 hours. There will be a threat for low level wind shear from 04z through 10z tonight with wind speeds of 50 KTS 1500 FT AGL. For the KVTN terminal: Thunderstorms are expected to develop across north central Nebraska after 01z. At the terminal strong storms are expected from 01z to 05z Thursday. Wind gusts to 40 KTS and ceilings around 2000 FT AGL is possible. The threat for thunderstorms will come to an end after 06z Thursday. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Buttler AVIATION...Buttler
Area Forecast Discussion
National Weather Service Marquette MI
727 PM EDT Wed Jun 17 2020 .SHORT TERM...(This evening through Thursday) Issued at 349 PM EDT WED JUN 17 2020 GOES WV imagery and RAP analysis highlight a tilted quasi-omega patterned, with a mid/upper level low over the northern Rockies and another over the southeast. At the surface to the west, a slow moving cold front has inched a little closer, kicking off convection in central North Dakota along the boundary. Between these cutoff lows, ridging extending from New England to the southern Plains has kept conditions dry over the Upper Great Lakes. Aside from some stray cirrus clouds over Lake Superior and parts of the Keweenaw this morning, its been a cloud free day. The clouds were associated with overnight convection over Ontario that got caught up in the anticyclonic flow. Temps have climbed into the 80s in the west and in the Keweenaw while in the east inland temps have climbed to near 80 so far. By the lakeshores, temps have been cooler in the 70s except by Lake Michigan where temps have topped out so far in the 60s. The exception to the lakeshore temps statement has been those prone to downslope adiabatic warming, such as Marquette that has climbed into the mid-upper 80s. Dewpoints staying in the 50s, which with the temps have kept RH values so far largely in the 40s with some 30s in the interior west and in the east, have kept the above normal temperatures bearable. Overall the pattern doesn`t change much this afternoon and overnight tonight, so expect temps to warm and dewpoints to fall a few more degrees before falling as the sun sinks toward the western horizon. The cutoff low to the west will migrate north into Saskatchewan and Manitoba tonight while the low over the southeast remains nearly stationary. This will keep the ridging and dry air over the Upper Great Lakes while the surface front over the northern Plains shifts a little more east. Given the persistent southerly flow and warmth aloft, expect temps to cool off some, but don`t expect overnight lows to fall to normal values for the time of the year. Overnight lows by Lake Superior should stay in the low 60s, as well as the high country of the Keweenaw. In the interior expect lows in the mid 50s and by the Lake Michigan lakeshore lows close to 50. Thursday, while still stuck between the mid/upper level lows, ridging will weaken as heights decrease and the approaching cold front edges closer. By the late afternoon/early evening, precip out ahead of the frontal feature should have moved into the far western lake and perhaps into the far western UP. Clouds will gradually fill in the western skies as the feature approaches, but in the east expect a mostly clear day. Highs should be similar to today`s, with interior and southerly downslope prone areas the warmest in the upper 80s and some isolated areas near 90. Steep low level lapse rates will promote some deeper mixing to around 4-5k ft. This should bottom out dewpoints in the low 50s and bring RH values into the upper 20s in parts of the interior west and 30s elsewhere. The deeper mixing will promote some gusty winds reaching down to the surface. Generally speaking, expect around 15-20 mph with some areas in the western interior and Michigamme Highlands reach 20-25 mph wind gusts. .LONG TERM...(Thursday night through Wednesday) Issued at 359 PM EDT WED JUN 17 2020 The extended starts out with a continued blocking pattern with quasi- rex block over southern Alberta and Saskatchewan with another cutoff low over the mid Atlantic / Ohio River Valley. These systems will move very slowly with the eastern cutoff low tracking up the New England coast by Tuesday. The low pressure in Canada will make slow progress into Ontario and be with us for much of next week. Precipitation chances will come up Friday as a weakening cold front stalls over the eastern UP. Instability combined with PWAT values of 1.5 inches in the deterministic models and approaching 2 standard deviations in the NAEFS anomalies could lead to locally heavy downpours with any thunderstorms that develop. Shear will remain weak so not expecting organized convection. Some upper level support with divergence at 300 mb will aid in developing convection. A series of shortwaves will affect the region Saturday through Sunday with multiple rounds of precipitation. Increasing low level moisture will keep fire weather concerns to a minimum through the weekend. It looks like a break in the active weather is possible for Tuesday as the shortwaves move off and the area is under the base of the upper level trough. Forecast temperatures overnight next week are in the low 40s over the interior from the blend but could trend cooler. Models do bring a few more shortwaves into the area by mid week so possible there will be enough clouds to limit radiational cooling. At this point went with the blend temperatures but will need to monitor as we get closer for possible frost. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 726 PM EDT WED JUN 17 2020 VFR conditions will prevail at all terminal sites through the forecast period. Only hiccup during forecast period is some LLWS expected at each of the TAF sites overnight with a low-level jet of 30 knots. KIWD LLWS should begin the earliest and last the longest. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 349 PM EDT WED JUN 17 2020 Today and tomorrow, high pressure will keep Lake Superior calm and under the influence of mainly southerly winds. The exception being high platforms that tap into winds above the marine layer; these could see some wind gusts above 20-25 kts;. Another exception are the NE winds blowing toward Duluth. Weakening cold front approaching from the west tomorrow afternoon may produce some showers/thunderstorms in the western portion of the lake by afternoon. Despite the cold frontal passage Thursday night into Friday, weak winds are expected with this feature and afterwards through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JP LONG TERM...JH/NL AVIATION...TAP/RJT MARINE...JP
National Weather Service Morristown TN
933 PM EDT Wed Jun 17 2020 .UPDATE... EVENING UPDATE. && .DISCUSSION... Showers generally dissipating across the area as surface cools. Area of showers approaching Tri-Cities area has been weakening, and cloud tops are steadily warming, so think that HRRR trend of fading these showers out, is on track as well. Am trimming back the POPs in Southwest VA somewhat before 06z, as later periods were dry enough already. No other changes at this time. GM && .AVIATION... 00Z TAF DISCUSSION. Upper low continues sluggish movement over general region. Lower ceilings over our area now drifting to southwest, with slightly higher ceilings wrapping into northeastern sections, might try to slowly erode lower ceilings initially at KTRI, then nighttime cooling will allow ceilings to lower again. Have some light fog forecast at KTYS/KTRI--tough to know how thick it will get with multiple cloud layers above surface, but brief clearing could allow for thicker fog to form. After sunrise any fog should be dissipating. Showers/storms possible with best chances during afternoon heating. GM && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 62 83 65 88 66 / 10 30 20 30 10 Knoxville McGhee Tyson Airport, TN 59 82 64 85 64 / 10 30 40 50 20 Oak Ridge, TN 58 82 62 85 64 / 10 30 30 40 20 Tri Cities Airport, TN 57 77 59 80 60 / 30 60 40 80 30 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$