Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/15/20

Area Forecast Discussion
National Weather Service Caribou ME
936 PM EST Sat Nov 14 2020 .SYNOPSIS... High pressure will build this evening and crest over the region tonight. Low pressure approaches on Sunday with a frontal system crossing Sunday night. Cold Canadian high pressure then gradually builds through the middle of the week. && .NEAR TERM /THROUGH SUNDAY/... 9:36 PM Update: Satellite imagery, observations and a couple webcams indicate that the sky is mostly cloudy to cloudy across most of the FA. Skies are mainly clear along the Downeast Coast up the Penobscot River Valley to near the Milo area. There will be an overall clearing trend overnight as high pressure builds into the region but I have adjusted that clearing for most based on the trends. Radar & observations indicate some snow showers and flurries in parts of Aroostook, Northern Washington & Northern Penobscot counties. We observed a brief period of flurries here at the office about 20 minutes ago. Expect this activity to end over the next few hours but we have adjusted the pops for the next few hours. The overall forecast remains in good shape with only minor tweaks based on the latest observations, webcams, radar images, and trends. Previous discussion: Tonight...Upper disturbance will be moving across the region this evening as seen on satl imagery w/this feature residing in Quebec attm. CAA and NW flow coming off the St. Lawrence and deep moisture available will be enough to allow for some streamer action in the form of light snow/flurries. The GEM and GFS matched up well w/this setup. The 12z NAM and HRRR show a line of activity running from NW ME down across the Baxter State Park region into Nrn Washington County. The llvl convergence shown by the NAM matches up well w/this as well. Not expecting more than at best 0.5 inches and this will be across the higher terrain. Clearing to take place overnight w/NW winds dropping off as high pres from the ridges across the region. It will be much colder than Friday night`s mins w/temps generally getting down into the 20s w/the far northern areas seeing upper teens and even some lower teens back toward the Allagash and N Woods region. Sunday will be starting out mostly sunny as the upper ridge moves right over the area and then passes east later in the afternoon. This will allow for some warming of the temps after a chilly start to the morning. Temps will be capped off though by early afternoon as clouds advance from the wsw. Many locations across the northern 1/2 of the CWA will top out in the mid 30s, while central and downeast areas will see upper 30s to lower 40s. A frontal system apchg from the w later in day will bring the leading edge of precip in wrn areas by later in the afternoon. Attm, stayed w/the midnight crew`s assessment of a mention of rain/snow in aforementioned area. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/... updated to change Monday night to Sunday night... Guidance for the Sunday night storm has trended a bit slower and warmer with less QPF. This resulted in snowfall amounts being cut back in northern zones, but there`s still decent potential for an advisory in NW Aroostook County. Accumulations may be further reduced by sleet too, but have stuck with rain/snow in the forecast for now. The secondary low along the warm occlusion doesn`t really take over and cut off warm advection. As a result, warmer boundary layer temperatures are pushed northward towards the northern border with a changeover to rain later Sunday night...a relatively mild day following Monday. The southerly low level jet is now more the focus of our attention rather than snow. With 70 kts at 925mb shown by all the models, a High Wind Watch has been issued to advertise the threat for Monday night. Stability does not appear to be a big impediment and mixing up towards 925mb or higher is a big concern. Power outages could be a problem. Wind advisories may be needed further north to include the Bangor area, but will let the night crew make that call. The precip will sweep across the area fairly quickly Sunday night with most falling within a six hour period and amounting to around a half inch to three quarters of an inch of QPF. For Monday, the milder air in the wake of the occlusion continues until Monday night when a cold front brings much cooler air for Tuesday into Thursday. Highs on Tuesday will be some 10 degrees cooler with a brisk west wind. With a decent supply of low level moisture and instability, snow showers will be a possibility in the western mts Monday night and Tuesday, but no accumulations are forecast at this time. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A trough of low pressure crosses Tuesday night into early Wednesday and brings the coldest air of the season for Wednesday into Thursday. Highs will only be in the 20s to lower 30s...some 40 to 50 degrees cooler than the record highs early this week. The cold advection will bring a lot of cu/stratocu fields with some upslope snow showers into Wednesday. High pressure builds Wednesday night, but since it`s a rather narrow ridge, it may be hard to get rid of low clouds for much of the night and this scenario favors the coldest temps in the North Woods where subzero temps will be possible. The ridge will be short-lived early Thursday as a rather dry northern stream warm front brings rapidly increasing clouds and the threat of snow or mixed precip later Thursday into Thursday night. Can`t see any snow accumulations more than an inch and some freezing rain or sleet seems possible by later Thursday night. Did not include in the forecast at this point due to timing uncertainties. A milder zonal flow emerges for late week with a return to more seasonable temperatures. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... NEAR TERM: Basically VFR for terminals into Sunday. The caveat will be this evening across some of the northern terminals, such as KPQI, KCAR and perhaps KHUL as a brief period of MVFR cigs & possibly some flurry activity. A more prolonger period of MVFR ceilings at KFVE through the evening. NNW winds 5-10 mph tonight becoming light overnight. Light and variable winds Sunday morning becoming SE 5-10 mph. SHORT TERM: Sunday night...Will feature IFR cigs and IFR vis in snow north of HUL. LLWS is expected...especially for BGR, BHB and coastal sites. Monday...IFR cigs north of HUL dissipate early and give way to MVFR cigs north of HUL. VFR is forecast further south. Monday night into Wednesday...Frequent MVFR cigs and a few snsh north of a GNR to HUL line. Otherwise VFR. Thursday...Chance of IFR vis in snow north of HUL by afternoon...otherwise VFR. && .MARINE... NEAR TERM: NW winds 15-20 kt this evening will gradually drop off tonight as high pres to the s apchs the waters. Seas 3-4 ft. N winds around 10 kt on Sun becoming SE and increasing to around 15 kt w/some higher gusts. SHORT TERM: A strong gale is expected Sunday night and have converted the watch to a warning. Can`t rule out a few gusts to storm, but confidence not high enough for a storm watch or warning at this time. The gale will probably continue in the outer waters all of Monday. Advisory conditions are expected mostly non-stop into Friday. && .TIDES/COASTAL FLOODING... High astronomical tides are expected Sunday into Monday. The very highest tides will be Sunday morning around 10 AM EST and again Monday morning near 11 AM EST. The Sunday evening tide is just a bit lower, but will be enhanced by a potentially strong storm surge that could make it the highest tide of the three. While all three tides could cause minor issues at prone areas such as Machias, the Sunday evening tide near 1040 PM EST could cause the greatest issues if the max surge coincides with the high tide. Using ESTOFS with the southeasterly winds rather than ETSS. With the elevated water levels, seas over 10 ft and an increasing wave period, wave runup could be an problem with the Monday morning high tide. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...High Wind Watch from Sunday evening through Monday morning for MEZ029-030. MARINE...Gale Warning from 7 PM Sunday to 7 AM EST Monday for ANZ050>052. && $$ Near Term...Hewitt/Sinko Short Term...MCW Long Term...MCW Aviation...Hewitt/Sinko/MCW Marine...Hewitt/Sinko/MCW Tides/Coastal Flooding...
National Weather Service Kansas City/Pleasant Hill MO
532 PM CST Sat Nov 14 2020 .Short Term...(This Evening through Sunday) Issued at 329 PM CST SAT NOV 14 2020 Short term filled with challenges as strong winds and thunderstorms impact the area. As stratus across eastern Kansas erodes, am seeing winds approach wind advisory criteria. South of the Missouri, it may be a struggle to reach full advisory level winds with the stratus expected to hang tough. With that said, conditions will be quite close to advisory, so will leave headline as is for the time being. CAMs have delayed convective initiation across central and eastern Missouri this evening closer to 00Z. Capping inversion near 800 mb looks to remain in place a bit longer, limiting convective potential through the late afternoon hours. With strongly sheared environment, effective bulk shear is expected to be in 50-60 knot range. With tongue of 500-1000 J/kg of CAPE, may be enough to result in scattered shower/storm development early this evening across central Missouri. Latest runs of the HRRR (18-19Z) are also suggesting development along the surface cold front towards 01-03Z. Surface inversion looks to be weakest across south central Missouri, suggesting that if convection is able to form, there may be a small window for convection to become near surface based near Clinton, MO early this evening. Outside of this area, expect the main severe weather threat to be severe wind gusts with 50-60 knots of wind poised just above the surface. As cold air advection increases behind the cold front after 03Z, 1000-900 mb lapse rates increase to near 8.5 degrees/km. This along with pressure rises of 3-5 mb/hr will likely result in a second period of increased winds. The increased winds are expected to only last 3-5 hours in any particular location, but have issued a wind advisory for much of the forecast area through the overnight hours. Strong westerly-northwesterly winds of 40-50 knots are expected to follow behind the cold front, and with the steepening low level lapse rates, expect wind gusts to surface for a period. Breezy conditions are expected to develop Sunday morning and slowly decrease through the day as winds in the mixed layer slowly decrease. With that said, expect wind gusts of 30-35 mph throughout the morning hours, decreasing through the afternoon hours. Have left the wind advisory as is for now, but will need to closely watch the top of the mixed layer and make sure mixing doesn`t climb into the stronger winds aloft. .Long Term...(Sunday Night through Saturday) Issued at 329 PM CST SAT NOV 14 2020 Jet stream is expected to buckle northward early next week with relatively quiet weather and above normal temperatures through the week. Potential for rain showers increases next Saturday as deepening trough across the west creates the chance for warm air advection showers. && .Aviation...(For the 00Z TAFS through 00Z Sunday Evening) Issued at 520 PM CST SAT NOV 14 2020 A strong cold front will move through the terminals early in the prevailing period. Southwesterly winds of 10 to 20kt with gusts up to 30kt will continue out ahead of the approaching front. Post- frontal, winds will veer to more westerly in direction but maintain a similar wind speed into early Sunday morning. Storms are beginning to develop ahead of the front, but are expected to remain south and east of the terminals KSTJ/KMCI/MKC. KIXD may see a brief period of VCTS between 00-01Z but given how quickly the storms are moving...any storms should quickly clear out of east- central Kansas and far west-central Missouri. Ceilings will predominantly be VFR with a possible scattered MVFR deck ahead of the front that will quickly rise to 9-12 kft behind the front. && .EAX WATCHES/WARNINGS/ADVISORIES... KS...Wind Advisory from 9 PM this evening to 4 AM CST Sunday for KSZ025-057-102>105. Wind Advisory until 6 PM CST this evening for KSZ057-060-105. MO...Wind Advisory from 9 PM this evening to 4 AM CST Sunday for MOZ001>006-011>015-020>023-028>031-037>039-043-044. Wind Advisory until 6 PM CST this evening for MOZ037-043-044-053- 054. Wind Advisory from midnight tonight to 3 PM CST Sunday for MOZ007-008-016-017-024-025-032-033-040. && $$ Short Term...BT Long Term...BT Aviation...PietrychaP
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
814 PM CST Sat Nov 14 2020 .UPDATE... 814 PM CST Evening update: No significant changes to going forecast this evening. Gusty showers and thunderstorms and very strong winds later tonight and Sunday continue to be the primary forecast concerns. No changes to wind advisory or marine headlines at this time. Evening surface analysis shows 996 mb low pressure over central IA, with a cold front trailing through Missouri into far southeastern KS at 01Z. East of the low, blustery southeast winds were across the western Great Lakes region within a tight pressure gradient maintained by a broad area of pressure falls in excess of 2-3 mb/3 hrs. An area of showers and isolated thunderstorms was working east- northeast over southern Lake Michigan and the IL/IN state line region, generally along the leading edge of stronger H8 moisture advection/convergence while patchy light rain/drizzle was occurring farther to the west over north central IL. Going forecast captures the expected trends nicely through the remainder of the evening/overnight hours. Forcing for ascent will continue to strengthen through late evening, in advance of a deep upper trough and a strong vort/jet streak transiting the region overnight. Showers and thunderstorms are expected to increase in coverage again mid-late evening, with the potential for a stronger line of low-topped convection ahead of the approaching cold front toward and just after midnight. Earlier cluster of low-topped cells produced a 40 kt wind gust at Rochelle, and with 50+ kts of SSW winds only about 1500 feet above ground level, any additional strong convection will have to be watched for some stronger gusty wind potential overnight. Surface cold front pushes through during the pre-dawn hours, which will then shift the concern to very strong synoptic (non-convective) winds as low level cold advection kicks in and steepens low level lapse rates, deepens the boundary layer and mixes down higher momentum from aloft. Surface gusts 45+ mph are likely to develop behind the cold front, as this deeper mixing and strong isallobaric gradient forcing aid in increasing westerly winds. Despite complexities of the weather scenario, going forecast has things handled very well, with wind advisory beginning at midnight and thunder chances quickly diminishing behind the cold front. Gradual slight warming of temps up until cold fropa also depicted nicely in hourly grids. Ratzer && .SHORT TERM... 300 PM CST Through Sunday night... The shower and thunderstorm chances tonight, followed by the likelihood of strong and potentially damaging wind gusts of 50-60 mph on Sunday are the primary forecast concerns during the short term period. ...Showers and storm chances Tonight into Sunday morning... Showers have been slow to develop early this afternoon, with much of the activity currently confined well to our south. However, more scattered activity has recently been developing just to our west near the Mississippi River. This uptick in showers, and even some storms will be the rule as we head into the early evening hours. This uptick in activity will be driven by the combination of increasing upper level jet dynamics over the area associated with the approaching upper trough to our west, and a strong northward surge occurring thanks to a strong lower-level mass response (Southerly low-level jet 50+ KT). With this in mind, confidence continues to be high with periods of showers through the evening, along with some thunderstorms given the steepening mid-level lapse rates. We also may have to watch for a strongly forced line of low topped convection around, or just after midnight ahead of an approaching cold front. This could produce some small hail, and/or help locally drag down some stronger wind gusts ahead of the approaching cold front. The upper level dynamics associated with the approaching upper level impulse will drive a fast northeastward moving and deepening area of low pressure from eastern IA early this evening to near the Straits of Mackinac by early Sunday morning. Gusty southerly surface winds will be the rule through the evening ahead of this area of low pressure, and its associated cold front. Because the area will be in the warm sector of this storm system tonight, expect temperatures to continue rising through the evening, with readings likely reaching into the low to middle 50s overnight before the strong cold front shifts eastward across the area overnight. The time of this frontal passage is likely to result in both todays and Sundays high temperatures occurring right around midnight tonight. Temperatures during the day on Sunday will likely remain nearly steady in the upper 30s to low 40s. After the cold front pushes across the area overnight the strong winds will become the main weather story, see more on this below. However, it appears that another batch of precipitation will occur across the area Sunday morning as a secondary disturbance, now over South Dakota, rotates through the larger scale trough. This will have to be watched as it could mix with, or even change to a period of snow over far northern IL during the morning. Given steep mid- level lapse rates remaining in place, this could fall a decent clip for a short period of time, potentially even leading to some minor accums in some areas. Confidence is not the highest with this changing to snow due to uncertainties on how warm the near surface airmass will remain. This activity should largely come to an end by midday Sunday. ...Strong Winds late Tonight and Sunday... For tonight`s winds, a tightening pressure gradient will develop between high pressure of 1023 mb over the east coast and a strengthening low pressure over Iowa. There will be pressure falls around 4-5 mb per 3 hr over the CWA. In addition, an 850-925 mb low level jet (LLJ) of 55-65 kt will develop later this evening. Tapping into these stronger gusts will be limited with indications of a stronger inversion with clouds and showers. Still some sporadic gusts of around 35 mph are likely, and a few higher are possible especially with any convection that is near the front. As the enclosed 990 mb low develops over Wisconsin overnight and progresses to Lake Superior Sunday morning, further deepening to sub 980 mb as it does so, the pattern will favor at least Wind Advisory conditions (45+ mph gusts) over the region with potential for a window of time to High Wind Warning (58+ mph gusts). Pressure rises of +7 mb per 3 hours just behind the front will create a very tight gradient and be assisted by cold air advection. This looks to maximize Sunday morning, right after daybreak, and persist through early to mid afternoon. One uncertainty to reach that 60 mph threshold will be the amount of clouds, but feel high confidence in 50 mph gusts with that degree of wind forecast on model soundings at cloud base layer. Also the HRRR and experimental HRRR continue to indicate gusts nearing or even reaching 50 kt across much of the CWA during that morning period, further adding confidence and suggesting we may at least temporarily reach 60 mph for gusts. While gusty winds look to continue into Sunday evening, expect the speeds to begin to ease. In addition to the wind advisory a lake shore flood advisory has been issued for Porter county IN for Sunday and early Sunday evening. The strong westerly winds are also expected on Lake Michigan, and this is likely to result in large waves up to 11 feet impacting the Porter county shoreline. KJB/BKL/MTF && .LONG TERM... 313 PM CST Monday through Friday... The forecast thinking for the extended period has not changed. Please reference the previous discussion below for more information. Overall quiescent conditions are expected next week as fast northwesterly flow continues overhead. A fast-moving disturbance is forecast to zip along the northern fringes of the fast polar jet on Monday. Most guidance tonight continues to suggest the core of this feature remaining north of the Wisconsin state line, but some ensemble members do suggest this getting close enough to at least thicken up the mid-level cloud deck. Main issue with this feature is that it will be accompanied by very cold temperatures aloft (getting towards -30 C at 500 mb) which will result in a plume of steep mid-level lapse rates as the main corridor of forcing for ascent arrives. At this time, the strongest isentropic upglide associated with this disturbance looks to be displaced enough from the main lapse rate plume to justify keeping the forecast dry (plus the rather dry sub-cloud layer in the place), but a feature to watch nonetheless as wet bulb temperatures would support column cooling to favor (convective) snow. Tuesday night may feature the coolest temperatures of the upcoming stretch as high pressure builds (briefly) directly overhead and winds go light and variable for a time. However, warm advection returns with gusto on Wednesday and especially Thursday which should allow temperatures to climb back to above normal values with some low to even mid 60 degree readings in place come Thursday. Thereafter, some low-grade precipitation chances get re-introduced over the weekend, as the next disturbance--a southern stream wave--scoots east across the CONUS. Lots of model spread with this one, and did not stray from the offered slight chance to low-end chance PoPs from the blended guidance. Carlaw && .AVIATION... For the 00Z TAFs... 547 PM...Several forecast concerns this period including... Strong/gusty southeast winds this evening. Very strong/gusty westerly winds Sunday. Chance of thunder this evening and again around 06z. Showers through Sunday morning...chance of snow Sunday morning. Possible ifr cigs this evening. Southeast winds gusting to 30kt will continue this evening... slowly turning more southerly by late evening and then to the south/southwest after midnight. Despite the these strong surface winds...winds aloft are strong enough to continue low level wind shear mention...especially when surface winds may be lower than expected. Speeds/gusts will increase overnight with gusts into the mid 30kt range possible. Winds will shift westerly before or around daybreak and by this time period...gusts will increase into the mid 40kt range. These very strong gusts will continue through the morning and will slowly relax into the 40kt range Sunday afternoon. Wind speeds/gust will slowly diminish Sunday evening but will remain gusty through much of the evening. Showers will continue to spread across the area this evening though there will likely be some dry periods. Isolated thunderstorms will remain possible but the duration of thunder should be short-lived at any one location but maintained the vicinity mention this evening. A better chance of thunderstorms is expected ahead of the cold front late this evening into early Sunday morning and tempo thunder still on track for this time period. Any of the stronger showers or storms may produce brief moderate/heavy rain and some vis reductions. There appears to be a break in the precipitation in the predawn hours but another wave will move across the area Sunday morning bringing rain showers to the area. It will turn cold enough that some snowflakes may mix with the rain especially at rfd. If there were a period of mainly all snow...ifr vis can be expected. Mvfr cigs have scattered out across part of the area early this evening and guidance has been backing away from ifr cigs this evening across northeast IL. Prevailing mvfr cigs are still expected though with showers moving through...cigs may remain somewhat variable over the next few hours. Ifr cigs are still possible across northwest IL including at rfd but even here... confidence is low. Mvfr cigs will continue through late Sunday morning...possibly into early Sunday afternoon before lifting to low vfr. Its possible another period of ifr cigs may develop with the rain or rain/snow showers Sunday morning and did include ifr cigs with the tempo at rfd. cms && .MARINE... 313 PM CST A strong storm system will produce a significant wind event on Lake Michigan late tonight through though Sunday. A period of storm force winds to 50 kt appears likely following a strong cold front, which will move across southern Lake Michigan late tonight. Westerly winds will quickly increase to 50 kt in its wake, and these strong winds will continue through much of the day Sunday. Winds will gradually ease below storm force late Sunday afternoon and evening, but some gale force winds could continue during the evening. A storm warning has been issued from late tonight through Sunday afternoon, during the period of strongest winds. The gale warning also remains in effect through 09z Monday. Expect the weather to improve for Monday. Carlaw/KJB && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Wind Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ023-ILZ032-ILZ033- ILZ039-ILZ103-ILZ104-ILZ105-ILZ106-ILZ107-ILZ108...midnight Sunday to 6 PM Sunday. IN...Wind Advisory...INZ001-INZ002-INZ010-INZ011-INZ019...midnight Sunday to 6 PM Sunday. Lakeshore Flood Advisory...INZ002...9 AM Sunday to 9 PM Sunday. LM...Gale Warning...nearshore waters until 3 AM Sunday. Gale Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 PM Sunday to 3 AM Monday. Storm Warning...LMZ740-LMZ741-LMZ742-LMZ743-LMZ744-LMZ745...3 AM Sunday to 3 PM Sunday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Blacksburg VA
950 PM EST Sat Nov 14 2020 .SYNOPSIS... Increasing clouds tonight as high pressure departs to our east. Windy conditions with showers Sunday as a strong cold front pulls through. Our next front arrives Tuesday bringing another round of wind and cooler conditions midweek. && .NEAR TERM /THROUGH SUNDAY/... As of 946 PM Saturday A broken to scattered deck of mid to high level clouds continues to stream in from the southwest. These clouds will continue to increase overnight as warm air advection takes over. Winds have also started to pick up with gusts close to 20 mph back toward Beckley and Charleston as our surface low over the Great Plains starts to deepen ejecting rather stout south to southwest low level jet our way. Precipitation wise, I have opted to back off on PoPs a bit through the early morning hours of Sunday by 1-2 hours based on how dry the low levels remain per the 0z sounding. Hi- res models continue to show this as well with a slower precipitation arrival time from the front itself and any shower activity that develops out ahead on south to southeasterly flow. Otherwise, no additional forecast changes at this time. As of 713 PM EST Saturday Some minor adjustments to temperatures and sky coverage through the overnight as well as precipitation chances early Sunday morning. Leaning toward a later start Sunday morning in overall rain chances along the southern crest of Blue ridge and back into the North Carolina mountains. Both the 12z and 18z model suites illustrate this with the NSSL, NAMnest, and CONShort the most aggressive in moistening the column due to isentropic lift from south to southeast return flow. For now opted for the 8-10z (3am-5am Sunday)window which lines up better with the current HRRR and ARW solutions. Overall the latest hi-res guidance pegs our front coming in between 15-19z Sunday before clearing the area Sunday evening. The front will bring with it several hours of sustained winds between 15-30 mph with gusts over 40 to 50 mph at times especially across the higher elevations. With that said a Wind Advisory will continue from 6am-7pm Sunday for the Greenbrier Valley, Alleghany Highlands, and North Carolina mountains. These areas are likely to see the highest winds across the regions starting around sunrise Sunday and continuing into the afternoon. Will reevaluate the advisory and look to see if we need to expand further east as the cold frontal boundary works in. As for temperature we look to warm a bit out ahead of the boundary as low level warm air advection builds with south to southeasterly return flow. On top of this high level clouds will continue to filter in acting as a thermal blanket overnight. Lows tonight will generally be in the mid to upper 40s. Highs tomorrow will top off mainly in the 60s for the west, near 70 for the east. && .SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY NIGHT/... As of 130 PM EST Saturday... Frontal passage Sunday will be followed by strong pressure rises, cold advection and decent gradient, low level jet. Soundings suggest that our normal mountain counties could get to advisory level winds of gusts over 45 mph Sunday night. Seeing the wind advisory ahead of the front, will wait another run of the models and ascertain where there will be a need for one Sunday night. Otherwise, high pressure works in from the southwest Monday but will still have some wind lingering, with colder temperatures with broad trough in the east. Next front arrives Tuesday and will likely see clouds increase with threat of rain/snow showers in the higher terrain of WV, but nothing of consequence for now, as fast flow and drier air limit precip. Another shot of colder air, with winds accelerating again, but models are not as strong with the low level jet, so sub-advisory winds anticipated Tuesday-Tuesday night. && .LONG TERM /WEDNESDAY THROUGH SATURDAY/... As of 138 PM EST Saturday... Building heights as ridge sets up over the southeast this period will bring milder temperatures and dry weather. A backdoor front edges toward the mid-Atlantic Saturday but not seeing enough of a push with the stronger high over the Carolinas. Temperatures should rise to at and above normal toward the end of the week. && .AVIATION /03Z SUNDAY THROUGH THURSDAY/... As of 713 PM EST Saturday... VFR conditions persists through this evening before the focus shifts to strong winds and precipitation impacting aviation concerns Sunday. Winds will start to increase beyond 6z-8z out of the south to southeasterly building high clouds and giving way to sub-VFR ceilings and LLWS at most of the TAF sites early Sunday morning. Confidence is a bit lower on the extent of clouds east of the Blue Ridge from KLYH to KDAN opening the door for an additional period of VFR around sunrise Sunday morning. Overall sub-VFR conditions are expected in the west throughout the TAF period as a cold frontal boundary enters the area. With strong south to southeasterly flow out ahead of the boundary an opportunity for VCSH or even a period of SHRA remains possible at KBCB, KROA ,KDAN, and KLYH early Sunday morning. Rain chances increase for KBLF and KLWB beyond the early morning period as the cold frontal boundary works into the region. Shower activity wraps up as the front looks to clear the area by 20-22z Sunday. Winds will persist though well into the afternoon sustained at 10 to 15 knots out of the south/southeast gradually shifting to the south/southwesterly direction. Gusts will also hang between 20-25 knots through latter half of the TAF period. Extended Aviation Discussion... A cold front will cross the region early Sunday evening. Expect limited sub-VFR conditions associated with this feature. Winds will become very gusty from the northwest by Sunday afternoon and remain gusty through early Monday morning. After a brief visit by high pressure on Monday night, another cold front will cross the region Tuesday into Tuesday night. Very gusty winds will again follow the passage of the cold front. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Wind Advisory from 6 AM to 7 PM EST Sunday for VAZ007-009>011- 015-019-020. NC...Wind Advisory from 6 AM to 7 PM EST Sunday for NCZ001-002-018. WV...Wind Advisory from 6 AM to 7 PM EST Sunday for WVZ042>044-507- 508. && $$ SYNOPSIS...ET NEAR TERM...ET/RR SHORT TERM...WP LONG TERM...WP AVIATION...ET/RR
...Update to aviation forecast discussion...

.UPDATE... Issued at 545 PM CST Sat Nov 14 2020 Forecast for a push of stronger winds remains on track for tonight based on upstream observations and CAM progs. Wind gusts of 40 to 45 kts are likely as the front pushes through between 01-04Z, decreasing from west to east after several hours. The presence of elevated precipitate lends some concern that additional momentum transport could be lent to the winds as they work through the area and will monitor trends closely in case winds approach warning levels. && .DISCUSSION... Issued at 217 PM CST Sat Nov 14 2020 20Z water vapor imagery showed a longwave trough over the northern and central plains. There was still signs of amplification of this trough as the trough was moving out into the plains. Further upstream a shortwave was noted off the Pacific northwest coast moving towards British Columbia. At the surface, a prefrontal trough bisected the forecast area north to south. Temps have warmed into the lower 70s ahead of this boundary while areas across north central KS have struggled to warm into the lower 60s. For this afternoon and tonight, the main concern is with the winds. Models show the pressure gradient relaxing across east central KS this afternoon as the prefrontal trough continues moving east. So I anticipated being able to let the initial wind advisory expire on schedule. The bigger concern is with strong pressure rises behind the front tonight. The RAP and HRRR continue to show the potential for wind gusts near 50KT which is strong enough for a high wind warning. Confidence in gusts this strong is not high enough to go with a warning at this time. The models show the pressure rises weakening through the night and statistically the gusts shown by the HRRR and RAP have about a 10 percent chance of happening. So will continue with the advisory. Have extended the advisories tonight to expire at 11 pm and 1 am since the overall progression of the upper trough and associated pressure rise have trended slower. Some of the guidance is trying to spit out some light QPF this evening. Forcing from the upper trough looks to be pretty strong, but moisture may be limited. Have been monitoring the radar returns across northwest KS and surface obs have not reported any precip while ceilings generally remained around 10 KFT. So have kept POPs below 20 percent with only a mention of sprinkles through the evening. Lows tonight will be cooler, but a strong pressure gradient is likely to keep the boundary layer mixed through the night. This is expected to hold lows in the middle to upper 30s. For Sunday through Friday, dry weather is forecast to persist. Models are in good agreement for northwest flow to develop for Sunday and Monday where there could be some perturbations within the flow. However a dry airmass is expected to preclude any POPs. Then an upper level ridging amplifies over the central U.S. through mid week. So rain chances any time soon do not look promising. Temps for Wed and Thu have trended warmed with the GFS and ECMWF showing good low level warm air advection. In fact Wednesday looks to be pretty breezy as the pressure gradient potentially strengthens again. There are some indications from the operational models for the next upper trough to move from the southwestern U.S. into the plains next weekend as a cold front sags south. So have some small POPs going for Saturday. The forecast this far out has some uncertainty as models differ on the timing and location of the frontal boundary. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 545 PM CST Sat Nov 14 2020 VFR conditions are forecast for the TAF period with scattered thunderstorms currently southeast of an EMP to LWC line rapidly exiting the area by 02-03Z. Westerly winds of 15-20 kts will rapidly increase out of the northwest between 01-04Z tonight with gusts of 40-45 kts likely at times. These winds lessen after 05-07Z, but remain gusty out of the west through the remainder of the TAF period. Should any decoupling happen tonight, LLWS would ensue, but confidence was not high enough to mention in the TAFs. && .TOP WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 1 AM CST Sunday for KSZ011-012-023-024-026- 038>040-054>056-058-059. Wind Advisory until 11 PM CST this evening for KSZ008>010- 020>022-034>037. && $$ UPDATE...Skow DISCUSSION...Wolters AVIATION...Skow
Area Forecast Discussion
National Weather Service Tulsa OK
923 PM CST Sat Nov 14 2020 .DISCUSSION... Scattered low-topped supercells continue over parts of western Arkansas near the nose of 700mb jet in unstable pre-frontal environment, and will continue to pose a severe threat for a couple more hours. Cold front currently located near Checotah to Gravette and will continue to sweep through the remainder of the area by Midnight. Front is forcing a broken line of storms, however updrafts quickly being undercut and as such, these storms pose little severe threat. Gusty northwest winds immediately in the wake of the front have been enhanced by convective cells immediately behind it, with brief gusts in the 40-45 mph range noted. Severe threat will end once the front clears the forecast area. Additional updates will mainly be to clear more counties from tornado watch behind the front...and have also upped wind speeds behind the front for tonight. && .PREV DISCUSSION... /Issued 506 PM CST Sat Nov 14 2020/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. The main concern with the potential for thunderstorms to impact the western Arkansas sites through 06z as a cold front sweeps through the region rather quickly. After 6z... the gusty northwest winds will be concern as ceilings clear out. PREV DISCUSSION... /Issued 145 PM CST Sat Nov 14 2020/ DISCUSSION... Primary concerns will be the convection trend the remainder of the afternoon and into the evening. Current visible satl imagery shows the back edge of the clouds over the part western parts of the forecast area, with considerable breaks in the overcast noted across parts of southeast into far eastern OK. If these trends continue, then afternoon instability may a bit higher than earlier anticipated. Recent runs of the HRRR appear to latch on to this idea, with scattered pre-frontal convection developing along OK/AR border around 21-22Z. A few of these storms could become severe, with forecast wind fields showing the potential for rotating storms. This activity would likely shift east of the area by early evening, although expect additional development as the cold front enters northwest AR around 03-04Z. This activity may pose a small severe threat, with storms quickly exiting the area by midnight. Will keep an eye on wind gusts over the next few hours, but anticipate leaving the current Wind Advisory as is. Sunday will be seasonally cool and dry, although temperatures will bounce back to above normal readings next week as mid-level heights rise. Went a touch above NBM guidance, with afternoon temps likely pushing the mid 70s in some spots by Thursday and possibly into Friday. Shower and thunderstorm chances look to increase next weekend as the upper flow becomes southwesterly and a cold front approaches. && .PRELIMINARY POINT TEMPS/POPS... TUL 40 61 38 67 / 10 0 0 0 FSM 44 62 36 68 / 30 0 0 0 MLC 42 60 36 66 / 10 0 0 0 BVO 39 60 35 66 / 0 0 0 0 FYV 39 58 32 65 / 50 0 0 0 BYV 41 57 37 65 / 60 0 0 0 MKO 40 59 36 64 / 30 0 0 0 MIO 37 58 35 64 / 30 0 0 0 F10 40 60 36 66 / 0 0 0 0 HHW 45 62 36 65 / 10 0 0 0 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...14
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
756 PM MST Sat Nov 14 2020 .UPDATE... Issued at 753 PM MST Sat Nov 14 2020 Extended the wind adv in the lee of the Black Hills where CAA/pressure rise squeeze will continue for another hour or 2, supporting wind gusts up to 50 mph. Rap H8-H750 winds highlight this well. && .DISCUSSION...Water vapor shows upper trof over the Northern Plains. Band of rain/snow along the cold front is shifting into central SD, with a bit of snow beginning to increase in our western zones with secondary cold front. Windy conditions across much of the region, although not quite as windy as initially expected. Cold advection with secondary front may push winds closer to high wind criteria from northeast WY into northwest SD briefly later this afternoon and early evening, but given winds have already been less than anticipated and the mid/late afternoon arrival of front may be a tad too late diurnally, have cancelled the Warning for northeast WY and downgraded to Advisory for northwest SD. Winds decrease by later this evening and overnight, with mostly sunny conditions for Sunday and highs mainly in the 40s. Another wave embedded in northwest flow aloft crosses the Northern Plains on Monday and will kick up the winds a bit more, but dry conditions expected. Upper ridge then builds in through mid week with dry and much warmer conditions likely. Temps into the 60s and even some 70s expected Wednesday, warmest south/east of the Black Hills. Flow may become a bit more unsettled towards the end of the week as ridge axis shifts east, with temps generally or slightly above average. && .AVIATION...(For the 00Z TAFS Through 00Z Sunday Evening) Issued At 415 PM MST Sat Nov 14 2020 Breezy NW winds will continue this evening, with ISOLD-SCT snow showers ending. MVFR to local IFR conds will be possible in the heavier snow showers. Conditions will improve late this evening to VFR, except possibly across parts of NW SD and the Black Hills, where MVFR CIGS may linger overnight. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until 8 PM MST /9 PM CST/ this evening for SDZ001- 002-012>014-025-027-030-032-041>044-046-047-049-074. Wind Advisory until 10 PM MST this evening for SDZ026-031-072- 073. WY...None. && $$ Update...JC DISCUSSION...Johnson AVIATION...JC