Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/22/19

Area Forecast Discussion
National Weather Service Albuquerque NM
548 PM MDT Fri Jun 21 2019 .AVIATION... 00Z TAF CYCLE Wildfire smoke from southern Arizona will move into central New Mexico this evening and continue into the overnight hours. The Woodbury fire is not quite as active compared to this time yesterday but areas of visibility will likely be restricted to between 5 and 8 miles in FU across much of central New Mexico overnight. Breezy to locally windy conditions will redevelop late Saturday morning, dispersing the smoke. 33 && .PREV DISCUSSION...312 PM MDT Fri Jun 21 2019... .SYNOPSIS... Very dry, warm, and breezy weather will continue through Saturday with areas of smoke likely around parts of central and western New Mexico. An unseasonably cool weather system will shift through northern New Mexico late Saturday through Sunday and usher in well below normal temperatures for late June. A few showers and storms are possible over the Four Corners region and the northern mountains late Saturday afternoon. A few of these storms may become strong with hail, high winds, lightning, and brief rainfall. Temperatures on Sunday will be 10 to 20 degrees below normal. High pressure will develop over New Mexico through next week with warmer temperatures again. The chances for showers and storms will increase each day next week as moisture begins trickling northward into the area. && .DISCUSSION... The latest water vapor imagery shows deep layer southwest flow in place over the southwest CONUS with very dry and hot conditions. Smoke plumes from several fires over NM and AZ are beginning to increase with southwest winds gusting up to 35 mph, temps in the 80s and 90s, and humidity values in the single digits. The latest HRRR smoke guidance shows another round of smoke moving into NM tonight before dissipating quickly Saturday morning. An Air Quality Alert has been issued again but for a larger area than last night. An unseasonably deep upper level trough entering the Great Basin today will move into the Four Corners Saturday and continue to force dry southwest flow over most of NM. Max temps will trend cooler over the far northwestern half of the state where mid level moisture will also begin increasing along an approaching cold front. Guidance is still consistent with showers and storms developing on the frontal boundary shifting southeast by late Saturday afternoon. Model moisture and instability does favor a few dry storms across the northwest with wetter cells closer to the CO border and within the higher terrain. Winds in the ABQ metro area will likely crank for an hour or two Saturday evening as the cold front moves in aided by convective outflow from the northwest. Meanwhile, a weak back door boundary will begin sagging into northeastern NM where a few light showers are also possible Saturday night. Temperatures on Sunday will be remarkably cool with highs 10 to 20F below normal for late June. Very dry air moving into the area behind the upper level trough with strengthening surface high pressure will lead to very chilly overnight lows for Monday morning. Near-freezing temps are possible in many northern and western valleys. Temps will rebound Monday with upper level high pressure building north into the region. Overnight lows will remain chilly for northern and western NM Monday night where strong radiational cooling takes place. High temps will continue trending warmer into Tuesday. Low level moisture will begin advecting northwestward into NM by late Tuesday while upper level high pressure continues building over the region. Each afternoon and evening through the end of next week will feature more coverage of showers and storms as moisture deepens over the southeastern half of the state. Guyer && .FIRE WEATHER... ...RED FLAG WARNING IN EFFECT FROM NOON TO 7 PM FOR AREAS ALONG AND SOUTH OF INTERSTATE 40 DUE TO STRONG WINDS, LOW HUMIDITY, AND AN UNSTABLE AIRMASS... ...DRY LIGHTNING POSSIBLE SATURDAY... Breezy to windy conditions will subside in lower elevations through the early evening with some ridge tops and exposed slopes keeping some periodic gusts (but still less than this afternoon). Overnight RH recovery will be considerably better tonight, but still only rising to 30 to 40 percent in many central NM zones through early Saturday morning. Smoke from AZ wildfires will also bring in haze and low visibility to much of central NM tonight. Winds will also shift direction in the northeastern quadrant of NM tonight as a weak front sags in. With the couplet of troughs aloft moving into UT and CO on Saturday, breezy to windy conditions will persist into NM with cooler temperatures feeding into the state. Concerns for marginally critical fire weather will be focused to the east central plains Saturday afternoon, but at this time the duration and spatial coverage of critical winds appears to be too low for any Red Flag highlights. Will continue to monitor this closely as high Haines indices are also pegged over this area, too. Also worth mentioning, a few showers and thunderstorms will attend/precede the latter trough progression. These could be fairly high-based with extensive evaporation beneath cloud bases and hence the potential for some dry lightning in north central to northwestern zones. These drier storms would also induce gusty and erratic winds of their own on local scales. With the aforementioned troughs passing into the plains by Sunday, wind directions in NM will veer a bit more west or northwesterly with breezy conditions still lingering. Mostly dry conditions will also prevail with cooler than average temperatures (by 5 to 15 degrees). Into next week, as a new dome of high pressure aloft builds over NM temperatures will gradually rise closer to normal. Beneath the ridge, low layer moisture will begin intruding the eastern plains zones, periodically attempting to filter into central zones. 52 && .ABQ WATCHES/WARNINGS/ADVISORIES... Red Flag Warning until 7 PM MDT this evening for the following zones... NMZ105>109. && $$ 52
Area Forecast Discussion
National Weather Service Denver/Boulder CO
832 PM MDT Fri Jun 21 2019 .UPDATE... Issued at 830 PM MDT Fri Jun 21 2019 There is still pretty decent coverage of showers and thunderstorms across the CWA at this time. Upstream satellite and radar pictures show that the northwestern CWA stands the best chance of continue convection for a few more hours. There is less upstream for the southeast CWA. The latest models keep good chance of showers going for the western and northern CWA much of the overnight period. Will make some adjustments to the pop, sky and weather GFE grids accordingly. I allowed the Severe Thunderstorm Watch to expire at 8 PM MDT. && .SHORT TERM...(This evening through Saturday) Issued at 300 PM MDT Fri Jun 21 2019 An unseasonable, deepening and occluding upper low over northern Montana is extending a trough into the Great Basin. Numerous showers and thunderstorms are occurring in the warm conveyor belt across Northwestern Colorado ahead of the 100 kt jet. Looking at visible satellite, the more stable air over northern Colorado has trapped waves in it, while below I-70 shows the more bubbling cumulus field denoting the instability. Only really expecting severe storm activity in this area, and perhaps slightly further north into Arapahoe County due to the east-northeast storm movement. HRRR has consistently been showing a swath of updraft helicity starting in Elbert County east into central Lincoln County. This would match up well with the best dewpoints. Expect the current storm activity over Douglas County to continue pushing east-northeast through the rest of the afternoon. Elsewhere across the plains, showers and weaker thunderstorms will continue through the afternoon and into the evening. A stronger push from the north will increase the coverage of rain showers and lower clouds as well through tonight. Then coverage is expected to decrease from the east into the early morning as flow aloft increases out of the south and upslope decreases. Over the mountains, snow continues to fall and accumulate over elevations of 9000 feet or so. Snow will likely be seen falling to elevations as low as 7500 feet, but there shouldn`t be much accumulation if any. The band of snow showers will be sinking south to lower snow amounts falling over zone 31, so having the advisory end by morning seems good, with another 2 to 4 inches likely to fall this evening and overnight. The jet will continue the SW to NE oriented band of snow further south on Saturday over the Front Range mountains. Another 1 to 4 inches are expected to fall during the day tomorrow. The upper trough will move into eastern Utah, with high surface pressure over the Great Plains keeping some stability over the plains. However, with enough moisture still in the area and the jet nearby, will continue to see a showers and cooler day tomorrow across the plains. .LONG TERM...(Saturday night through Friday) Issued at 300 PM MDT Fri Jun 21 2019 The broad summary for the extended forecast is a transition from a cold springlike storm system containing widespread showery precip over to a more seasonal pattern as a warm and dry stable ridge of high pressure begins to build into the region Monday into late next week. Starting with Saturday night, the coldest piece of the melt-day storm system begins to the enter the northern and central portion of the state as the base of the elongated and positively tilted trough bottoms and begins to pull eastward. This is the time frame when the last impulse of mountain snowfall arrives as a 70-80kt jet rounds the bottom of the trough over the OK panhandle placing the CWA under the left exit region of this feature. Across the lower elevations, a moist adiabatic sounding develops and remains in place into early Sunday with easterly flow up to 700mb. The ending of the Winter Weather Advisory for the higher mountains looks on track for 12z Sunday. Early Sunday, temperature guidance runs have come in a bit colder and are nudging into record low territory for Sunday morning. The record low for June 23rd in Denver is 43 degF, so keeping current grid temps in the lower to mid 40s is still on track despite the likelihood of early morning cloud cover and scattered showers. Later in the day, models are fairly synced with the timing of the exit of the trough around midday as QG fields bring a sharp gradient of subsidence over the state by late afternoon Sunday. The NAM is quickest to bring this subsidence in. Forecast soundings and cross sections still indicate a moist adiabatic profile up to 300mb thru 18Z as cold northerly flow is in place behind the exiting trough. This will likely keep orographic rain and snow showers going trough Sunday afternoon across the mountains with snowfall over the highest ranges especially on northwest and north aspects. Across the plains Sunday afternoon, will expect a mostly cloudy scene especially in the morning with enough surface heating to provide mixed layer capes in the 200-800 J/kg range. So, will likely see the unsettled weather continue into Sunday evening with scattered showers and fast moving weak thunderstorms in northwest flow aloft. As we head into late Sunday night and early Monday, NAM surface fields indicate light westerly surface flow, so not expecting widespread overnight post-storm fog at this time for Monday morning but can`t rule out some patchy dense fog in low lying areas. At this time, forecast soundings and cross sections begin to declare an end to the wintery and cold springlike episode as the atmos drys out and brisk northwest flow develops. By midday Monday, the beginning of a prolonged warmer and dryer period ensues. Hints of a weak ridge axis over AZ and UT begins to develop across the Great Basin as the cold, precip producing trough moves out onto the Great Lakes and Ohio Valley region. By early Tuesday, the stable ridge becomes more amplified but with good daytime heating, isolated showers and weak storms should develop over the higher terrain and push out onto the plains. Across the plains, soundings are mostly dry and V shaped, so isolated gusty weak storms will be the rule in the afternoon and early evening. For Wednesday, the ridge axis becomes aligned over the central US. At this point, medium range models indicate subtropical moisture drawing northward into the southern and central Rockies and central US plains in typical summerlike fashion under the dominant ridge centered over TX and Gulf south. This pattern persists into Friday while supplying enough moisture each afternoon for isolated showers and storms to fire off the higher terrain and push out onto the plains. With the dominant ridge holding firm over the southern portion of the US and warm/dry stable flow aloft persisting off the eastern Pacific, Thursday looks to provide the first 90 degF day of the season. No significant pattern change for Friday with temps holding above seasonal average with isolated afternoon storms. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 830 PM MDT Fri Jun 21 2019 The low level winds at DIA still are still easterly this evening. Models have them going southeasterly before 06Z but never becoming true drainage anytime overnight. Overall it is pretty difficult for overnight winds not to go to drainage, however the pressure gradient in place may keep them a but east of due south overnight. Concerning ceilings, models show them to be BKN- OVC025-040 all night into Saturday. Upstream radars picture show showers and a few thunderstorms should continue off an on over DIA for the next 2 or 3 hours. && .BOU WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM MDT Sunday for COZ033-034. Winter Weather Advisory until 6 AM MDT Saturday for COZ031. && $$ UPDATE.......RJK SHORT TERM...Kriederman LONG TERM....Fredin AVIATION.....RJK
Area Forecast Discussion
National Weather Service Charleston SC
1012 PM EDT Fri Jun 21 2019 .SYNOPSIS... A stationary front will remain across the region through this weekend. High pressure is expected to build over the Southeast U.S. early next week. A cold front is forecast to slowly move across the Coastal Plain Wednesday into Thursday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Regional radar composite shows an impressive late-evening MCS moving across the Tennessee Valley. This feature is outpacing much of the mesoscale guidance tonight, which is not unusual for these features. Both the RAP and H3R are now showing some form of the MCS and its associated wind shift moving into the western zones by daybreak and offshore shortly thereafter. RAP instability profiles show a fairly sharp noctural instability gradient setting up along the Savannah River all the way up into the South Carolina Upstate so it seems reasonable the MCS will continue to propagate to the southeast as moist, unstable air feeds into it from the south. Per coordination with neighboring WFOs, pops were increased slightly to 20-30% and a shift wind shift was populated into the hourly wind grids for the late evening update. It does not appear at this time that the MCS will pose a significant wind threat far to the southeast, especially as it approaches during the typically unfavorable diurnal minimum. However, this will ultimately be governed by mesoscale processes such as cold pool maintenance. Gusty winds could still occur with an isolated damaging wind gust being possible across the far interior, especially over areas that saw wind damage with Thursday`s severe weather event. Lows will range from the mid 70s inland to around 80 at the coast. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... A very complicated forecast for Saturday. IR satellite data shows a very large Mesoscale Convective System (MCS) tracking across the Mid West this afternoon. Short-term guidance indicates that the MCS will reach the southern Appalachians late tonight. It is suspected that the convection will gradually dissipate in the wake of the mountains. However, remnant showers and isolated thunderstorms should survive to the Coastal Plain during the early daylight hours. I will highlight the timing and placement of the convection with slight chance PoPs until 10 AM. The rest of the morning into the early afternoon, the forecast will remain free of convection across the area. Forecast soundings indicate a low-level inversion around 850 mb during the morning and forecast to mix out by the mid- afternoon, this inversion should keep the boundary layer capped during the morning. Debris clouds are expected to dissipate by mid-day, strong insolation should occur through mid-afternoon. High temperatures are forecast to range generally in the mid 90s away from the coast. The high temperatures combined with dewpoints in the mid 70s should result in heat index values between 105 to 109 across the coastal and most inland areas from late morning through the afternoon. A Heat Advisory has been issued from late morning until 6 PM. The hot temperatures combined with dewpoints in the low to mid 70s should result in CAPE values between 2500-3000 J/kg Saturday afternoon, per forecast soundings. In addition, wind profiles are forecast to become unidirectional with shear increasing to around 25 knots. Models indicate that a second MCS will cross the mountains during the Mid-day. The mountains should disturb the cold pool, with a cold pool sliding SE across GA. The arrival cold pool should trigger new convection, likely organizing into multicell lines. The storm structure and moderate values of DCAPE should support damaging wind gusts with the stronger cells. The severe risk should occur during the late afternoon into the evening. The region has been highlighted with a slight risk for severe thunderstorms. Sunday and Monday, the mid ridge axis is expected to ripple over the region. The environment should support scattered to isolated diurnal thunderstorms each day. Hot temperatures and dewpoints in the low to mid 70s are forecast to result in heat index values around 105 across the coastal counties each afternoon. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Weak troughing will prevail across the Southeast. The typical afternoon/evening showers/thunderstorms are expected. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR. Gusty winds likely by mid-morning once the morning inversion breaks. A large mesoscale convective system (MCS) is expected to develop across parts of Georgia into South Carolina tomorrow, which could push through the area late in the afternoon or early evening. Timing is a bit uncertain, but tstm impacts are possible at both KCHS and KSAV by the end of the 00z TAF period. Will not include a mention at either terminal at this time given any impacts will be very late and timing is still uncertain. Extended Aviation Outlook: Brief flight restrictions are possible in afternoon/evening showers/thunderstorms. && .MARINE... Tonight: Southwest winds will prevail through the night. A sharp wind shift to the west could occur just after daybreak as the remnants of a MCS move into the coastal waters. This wind shift could pose a risk for isolated wind gusts in excess of 30 kt, mainly where isolated convection lingers. Mariners are urged to remain alert for potential impacts just after daybreak. Sunday through Wednesday: Winds/seas are expected to remain below Small Craft Advisory criteria. A front will remain nearly stationary across the area through this weekend. High pressure will gradually build across the waters early next week. Wind directions will vary from day to day, keeping the development of swells limited. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Heat Advisory from 10 AM to 6 PM EDT Saturday for GAZ099>101- 114>119-137>141. SC...Heat Advisory from 10 AM to 6 PM EDT Saturday for SCZ042>044- 047>052. MARINE...None. && $$
Area Forecast Discussion
National Weather Service Dodge City KS
544 PM CDT Fri Jun 21 2019 ...Updated aviation section... .SHORT TERM...(This evening through Saturday) Issued at 1213 PM CDT Fri Jun 21 2019 An outflow boundary from morning storms has stalled out along the highway 56 corridor...given the cooler stable air I lowered afternoon highs north of this boundary while keeping temps to the south closer to the mid to upper 90s. Looking towards this evening another shortwave will propagate from northeast Colorado into northwest Kansas. The setup will bring a cold front into western Kansas through the overnight. Storms will likely propagate along the cooler 700 mb temps in northwest Kansas into south central Nebraska as much of our area will see 700 mb temps warm to 15-17 (C) which would keep us plenty capped even with the cold front passing through. Some short term models are suggesting saturation and low clouds developing behind the cold front around sunrise (5 am- 8 am) which may produce patchy to areas of fog mainly from Dodge City to Hays where winds should be lighter initially. Saturday the main question is how far south and east the cold front moves through the areas along and east of the front will have a severe weather and flooding risk. As you would expect all the models have different ideas how far east the front goes but the general idea is that it will stall somewhere east of a Dodge City to Hays line. Dew points ahead of the front will increase through the day with good moisture from the south. By late afternoon a shortwave is expected to move into western Oklahoma where storms will start to break out along the front and train north and eastward. PW values of 1.25-1.75 in. in this area will suggest this time frame as the start of a flash flooding risk with the higher risk of flooding during the night Saturday. Severe risk will also be present along the front with hail and wind. .LONG TERM...(Saturday night through Friday) Issued at 144 PM CDT Fri Jun 21 2019 A second round of thunderstorms will develop Saturday night in the front range of the Rockies with a large upper trough moving into central Colorado and a shortwave rotating around the low. Some models think the heavy rain will spread into northwest and north central Kansas while I noticed the latest 39 hr RAP wanted to take the heavier rain further south. Nonetheless I think areas in our southeast could see two rounds of heavy rain which will keep the flash flooding risk there into Sunday morning. The upper level trough/low slowly moves eastward into Sunday and long term models are suggesting a pretty cool day with northerly winds, clouds, and periodic rain showers/storms. We may only see highs in the 70s. Trough should be out of the region by Monday morning. For early next week we transition from a zonal to a ridge pattern. The main uncertainty is if we will be under the ridge or on the northerly extent of the ridge. Long term models seem to think that we will still be having some shortwaves and decent moisture riding the ridge which could give us some scattered storm chances most notably Wednesday and Thursday. However what does seem more certain is a stretch of 90 degree weather for much of next week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 542 PM CDT Fri Jun 21 2019 A cold front that will move through western Kansas during the overnight which could produce some post frontal low clouds, especially for DDC and HYS from 11Z-15Z. Winds will increase out of the northeast to 15-25 kts as the cold front moves through the area. Cloud ceilings should fall for all TAF sites mainly to MVFR with some IFR conditions as post frontal stratus develops. && .PRELIMINARY POINT TEMPS/POPS... DDC 67 84 59 77 / 0 20 50 20 GCK 62 81 56 76 / 0 10 50 10 EHA 61 82 55 76 / 0 0 40 10 LBL 66 85 60 77 / 0 10 50 10 HYS 63 74 57 73 / 10 10 70 20 P28 73 92 69 83 / 10 40 60 20 && .DDC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch from Saturday afternoon through Sunday morning for KSZ066-080-081-089-090. && $$ SHORT TERM...Tatro LONG TERM...Tatro AVIATION...Hovorka_42
Area Forecast Discussion
National Weather Service Grand Forks ND
959 PM CDT Fri Jun 21 2019 .UPDATE... Issued at 956 PM CDT Fri Jun 21 2019 Rain continues to move east across eastern North Dakota and into parts of far western Minnesota. Little to no thunder has been observed or is expected tonight. Mostly light rain showers, but a few localized areas of moderate to heavy rainfall has been reported. UPDATE Issued at 649 PM CDT Fri Jun 21 2019 The window for severe weather appears to be closing with instability never making in far into North Dakota and the best shear continues to be out over the western half of North Dakota. Still expect rain showers with some isolated thunderstorms this evening in eastern North Dakota. Some rain showers may make into northwest Minnesota as well later this evening into overnight but many of the CAMs have rain coverage diminishing as it crosses over the Red River Valley. && .SHORT TERM...(This evening through Saturday) Issued at 317 PM CDT Fri Jun 21 2019 Data indicates that the time period of severe weather if it would occur will be brief and may well be in the eastern part of BIS CWA in the 22z-01z period. Considerable cloud cover and showers are developing in central ND ahead of the surface trough/front and upper low forcing. There is a narrow zone of partial clearing trying to occur from Aberdeen NNW to about Ashley, Edgeley ND. This zone per HRRR, RAP and other models is in the zone with the mostly likely chance for destabilization and dew pts reaching 63/65 and capes reaching 1500-2000 j/kg for a brief time late aftn. HRRR reflectivity and Updraft Helicity fcsts indicate this area as well as showing some signals for severe storms. But this zone is rather narrow and as storms move away form this area past 01z the instability drops quickly toward the Red River valley with general showers/t-storms the result. Chance for showers/t-storms later tonight will diminish as the surface front/trough dissipates as it moves into Minnesota Saturday will see drier airmass spread thru central ND into DVL basin. Best sunshine in that area but will need to watch for a few t-storms along eastern edge of this drier airmass over parts of E ND. Farther east the main low level moisture corridor will be over western Minnesota and therefore higher rain chances Saturday for areas along and east of the Red. No severe risk. .LONG TERM...(Saturday night through Friday) Issued at 317 PM CDT Fri Jun 21 2019 Showers will end in NW/WC MN Saturday evening. Sunday to Tuesday... Much of the long term is dominated by the large upper-level low tracking into Canada. For the day on Sunday, models are in good agreement regarding the low, which will be located in eastern Saskatchewan and slowly move further to the northeast. Guidance suggests moisture advection from the south, which helps to keep the pattern active with showers and thunderstorms. Wednesday through Friday... As the low continues to track into northern Manitoba, meridional flow aloft continues over the area. Models are in agreement that ridging will take place over the area for the day on Wednesday, leading to continued warming. This heating, combined with embedded shortwaves, shows the possibility of stronger thunderstorms. Uncertainty still exists at this point, but any initiated convection could have an unstable environment given by moisture content and daytime heating. To end the week, look for the ridging to steepen && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 649 PM CDT Fri Jun 21 2019 Light to moderate rain this evening at KDVL and as rain showers pass through. This area of rain will move east into the KGFK, KFAR, and KTVF terminals later this evening into the overnight. Generally expecting rain, but a thunderstorm could be in the vicinity of a terminal this evening with the most likely location being at KFAR. VFR conditions falling to MVFR during rain showers with a chance of IFR if a thunderstorm approaches. Some gusty winds continue at all terminals with some gusts in the the 20 to 25 knot range. Winds should lessen late this evening into the overnight. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...NC SHORT TERM...Riddle LONG TERM...Lynch/BSW AVIATION...NC
Area Forecast Discussion
National Weather Service Hastings NE
631 PM CDT Fri Jun 21 2019 .SHORT TERM...(Tonight) Issued at 252 PM CDT Fri Jun 21 2019 12Z upper and satellite water vapor imagery showing a large upper low situated over MT/ID/WY with overall troughing over the Rockies. Meanwhile ridging was noted to the east over the MS river valley with troughing over the east coast. Decent 30-80 meter 500 mb height falls ahead of the western low pressure. Meanwhile at the surface, low pressure was noted in far northeast MT with a cold front extending into the central Dakotas and Neb and then curling west into CO. Another surface low was sitting over southern KS, just southeast of DDC at 17Z with a warm front stretching east and a dry line dropping south. Dewpoints were in the low/mid 70s along and south of the warm front compared to mid 30s behind the dry line. The question for late this afternoon and into the overnight involves the chance for precipitation once again. CAMs are showing a couple of possibilities, one being along the front beginning in the northwest part of the CWA late this afternoon and continuing into the evening. Doesn`t appear to be a lot in terms of mid/upper level forcing to help this along but convergence along the front may be sufficient for at least isolated activity. Instability not off the charts but models are progging 1500-2000 j/kg of ML-CAPE, while deep layer shear currently running about 40 kt. As of 19Z, GOES East Day Cloud Phase Distinction RGB product is showing convective initiation in central SDak along the front and this may be unzipping into north central Neb. Possible convection will need to overcome some CIN in our CWA especially further south. A second area of concern is to our west, northeast CO and western KS. HRRR is once again popping convection here and then sliding it ENE into our CWA sometime just prior to or after midnight. Each of the runs today have been consistent in weakening these storms as they move towards us, although the 17Z run does show one storm maintaining its strength as it moves in between 06 and 08Z tonight. For now will keep higher Pops in the NW early and then continue throughout most of the CWA with possible storms moving in from the west. .LONG TERM...(Saturday through Friday) A chance of showers and isolated thunderstorms continues for the weekend as the upper low remains to our west. The surface cold front should push into southwest to northeast KS and stall out. We may see off and on post frontal precip but the far better chance for severe and heavier rain should remain to our southeast. That said, will need to monitor the frontal position as it may end up close enough to the southeast CWA to result in severe storms. By Monday morning then 500 mb trough axis will finally push east of us with ridging building in from the west. For the rest of the work week and possibly into next weekend a more summer like pattern prevails with the ridge holding steady from the desert southwest into the Plains. Expect highs to be much higher with upper 80s to lower 90s the norm. Rain chances become much less likely although not totally zero as we end up in the "ring of fire" pattern with weak waves rotating around the ridge. The question then becomes, does any storm activity move over us, or is it further north and east. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday) Issued at 631 PM CDT Fri Jun 21 2019 There will be a chance for thunderstorms this evening and overnight. How widespread they will be is to be determined, and so have only included a VCTS at this time. Will amend as necessary. The front is not far to the northwest of the terminals and have brought gusty north winds in, in the next hour or so. MVFR to IFR ceilings are possible during the day tomorrow with northerly winds. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...Ewald LONG TERM...Ewald AVIATION...Billings Wright
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1055 PM EDT Fri Jun 21 2019 .SYNOPSIS... Showers and thunderstorm activity will return this weekend and persist off and on through much of next week. Near seasonable temperatures are expected to prevail through the next seven days. && .NEAR TERM /THROUGH SATURDAY/... As of 11pm EDT Friday: Upstream convective system is currently in Eastern TN and is expected to reach the TN border and parts of Northeast Georgia in the next couple hours, with a severe thunderstorm watch in effect for the western part of the CWA where CAPE is elevated. A Mesoscale Convective Complex (MCC) has developed atop the ridge over northern Missouri, and convection driven by the associated cold pool continues to run eastward into southern Illinois, with additional activity developing over south-central MO. These features will become the main players in our forecast for the upcoming nighttime period. Corfidi vector steering flow should drive the system mainly eastward toward the Appalachians, but with additional south flank development expected as the cold pool encounters better instability there. The convection-allowing models have converged on a solution with more of a direct hit of the MCS on the southern Appalachians overnight. The HRRR has the system arriving the fastest (circa 05Z) and surviving east of the mountains through 08Z or so. The NAMNest and national hi-res solutions are a touch slower, with varying decay as the system traverses the higher terrain and encounters stabler air. Given the latest solutions, will feature more solid chances over the NC mountains for the overnight hours, and advertise isolated to scattered coverage eastward through the lower piedmont. The HWO wording has been beefed up accordingly for mountain areas. Saturday is a major question mark for the timing and coverage of the next round of MCS activity, especially in light of the early morning passage of the decaying MCS late tonight. There are some features that suggest the afternoon timing will be favored. First, the region just east of the central CONUS flat ridge, mainly over the lower Ohio Valley and surrounding areas, will provide a prime area of genesis for further MCS activity through Saturday. This appears tied more strongly to weak upper shortwaves or MCVs moving down the east side of the upper ridge and this activity would time out toward Saturday afternoon. Also, a boundary will be in place across the forecast area through the day on Saturday, and peak afternoon instability will lead to maintenance of the passing MCS, if one forms. All told, will feature a peak of coverage (likely northwest to solid chance southeast) for the afternoon hours. The latest Day 2 Slight Risk Outlook looks well placed, with some 3000+ muCAPE likely south of the stalled boundary. This too will be talked up in the HWO for mainly wind potential. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 200 PM EDT Friday: The forecast area will remain on the east side of a mid level ridge axis on Saturday night and Sunday. This position in the flow looks to be active with convective complexes moving through and some local development of storms also possible both periods. A few of the storms may be severe per the SPC Day 2 outlook. The ridge axis will move across the area Sunday night and east of the area on Monday. This will lead to a quieter period Sunday night and most of Monday. A mid level trough moving across the Great Lakes states is expected to activate a front moving across the Tennessee Valley on Monday afternoon. Some of this activity will move into the mountains during the late afternoon hours. The forecast for Sunday will feature highs in the upper 80s to lower 90s in the Piedmont and mid 80s in the mountain valleys. The overall pattern suggests that debris cloudiness and possible leftover convective boundaries may have an impact on these readings. We may have to make some adjustments once the timing and location of storms become more clear. With less cloudiness and the ridge overhead, Monday looks to be the hottest day of the week. We expect highs in the lower to middle 90s in the Piedmont and in the mid to upper 80s in the mountain valleys. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 200 PM EDT Friday: A potent upper trough is expected to lift northeast into the Great Lakes states Monday evening driving a rapidly weakening cold front through the region sometime Monday night or Tuesday morning. A few showers and thunderstorms will be possible with the front. Moisture will decrease slightly for the middle of next week so the chance of showers and thunderstorms will be lower than this weekend which is closer to climo. Temperatures will be near or slightly above climo. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... At KCLT and elsewhere: Very weak pressure gradient in post-frontal regime is giving generally light northerly to northwesterly winds, with a few gusts still seen that will fairly quickly die-out diurnally. Skies are also mostly clear at the moment as moisture has been shunted southward with the front. These good VFR conditions will likely change early Saturday morning as the remnants of an MCS cross over the Southern Appalachians. This is expected to give a period of a few hours of scattered showers to the region, and possibly some thunder. By Saturday afternoon, front lifts back northward bringing increasing moisture, clouds, and chances for afternoon thunder with it for Saturday afternoon. Timing of showers in the TAFs was derived from the HRRR model and other cams. Latest radar has upstream MCS, currently over western KY and TN, a little ahead of schedule. Outlook: A more diurnally-driven convective pattern is expected Sunday through Tuesday, with some mid-week drying possible. Mainly daybreak restrictions will be possible each day, aside from any thunderstorms. Confidence Table... 03-09Z 09-15Z 15-21Z 21-00Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 100% High 100% High 100% KHKY High 100% High 100% High 95% High 100% KGMU High 100% High 100% High 100% High 100% KAND High 100% High 100% High 100% 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 and ensemble forecasts are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...SW NEAR TERM...HG/WJM SHORT TERM...SW LONG TERM...SW AVIATION...WJM
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
916 PM CDT Fri Jun 21 2019 .UPDATE... Updated for evening discussion. && .DISCUSSION... Rest of tonight: A decaying MCS has propagated southeast through the Mid Mississippi Valley & Mid-South, producing widespread wind damage as it moves through. Overall this complex continues to become more cold pool & outflow dominant over northern Mississippi & should become less robust as it propagates southward. Model CAM suite doesn`t have a good handle on this complex. Main updates to the going forecast were to add some PoPs for areas in north-northeast Mississippi (i.e. from around Grenada across to Lowndes County and Golden Triangle) as there is some potential for some rain chances to sneak into our area. Some light rain or an isolated storm can`t be ruled out. There is high instability but with increasing subsidence inversion & forcing off to the north & east, think potential is very limited in any more organized convection potential. We may still struggle to get much convection or rain at all, but wanted to account for anything that could sneak into the area. Updates are out or will be coming out shortly. /DC/ Prior discussion below: Tonight and Saturday: Mid afternoon surface analysis had a 1020mb high ridging across the Florida peninsula and across the northern Gulf of Mexico. This was resulting in very moist air from the Gulf move up across our CWA and maintain mid to upper 70 dew points while temperatures climb through the lower 90s and into the mid 90s. This was resulting in heat index values between 105 and 110. A Heat Advisory was expanded earlier to include the whole CWA til 7PM. Satellite and RAP analysis also indicated a mid level ridge across our CWA from the south. This combined ridging surface and aloft has led to an inversion noted on regional soundings this morning that has continued to limit convection over our area. Local radars were showing the first hints of isolated shower development near Highway 84. Isolated showers and thunderstorms will remain possible perhaps as far north as Interstate 20 through early evening but will dissipate rapidly with the loss of daytime heating. Although tonight will be dry, it will be very warm and humid. Morning lows will be above normal in the mid 70s at most locations. Ridging surface and aloft will continue to dominate Saturday. A little greater mixing is expected which will result in slightly lower peak heat index values. Still, with temperatures climbing back into the low to mid 90s along with lower 70 dew points, heat index values will be around 105. Wl carry a "limited" for heat stress areawide in our HWO. Saturday night through Thursday: The ridging aloft will shift east Sunday as troughing deepens over the central CONUS. Wl maintain surface ridging from the southeast that wl preserve our moist airmass. There will likely be pockets across the CWA that the peak heat index value approach 105 again. Most of the CWA will remain dry but rain chances will return to the west by Sunday afternoon that may provide some relief from the heat. Rain chances will increase from the west Sunday night into Monday. Models differ on the strength of the upper level trough and associated cold front but agree that our next best chance for widespread rain will be on Monday. The upper level trough axis will shift east of Mississippi Tuesday but the stalled front looks to linger over our CWA and provide a focus for convection through Tuesday. Our region looks to remain in a weakness between mid level ridging from the east and from the west through Friday. Depending on how far south the weak cold front stalls before returning north or washing out, at least diurnally driven chances for rain will continue for most of our CWA through Friday. Slightly cooler than normal temperatures are expected Monday and Tuesday with a slow warming trend through the end of the week. Otherwise, warmer than normal morning lows will continue through Friday. /22/ && .AVIATION... 00Z TAF discussion: VFR conditions are occurring this afternoon and should prevail through the evening. MVFR to patchy IFR ceilings should develop after 09Z tomorrow and lift by 15-16Z. VFR conditions expected after that. /28/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 76 94 73 92 / 3 5 6 10 Meridian 76 94 72 95 / 4 5 11 8 Vicksburg 77 94 74 93 / 4 7 4 13 Hattiesburg 76 95 73 94 / 4 5 3 10 Natchez 77 93 74 93 / 4 5 3 16 Greenville 77 94 75 92 / 3 8 10 15 Greenwood 76 93 75 93 / 2 10 9 9 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ DC
Area Forecast Discussion
National Weather Service North Platte NE
817 PM CDT Fri Jun 21 2019 .UPDATE... Issued at 813 PM CDT Fri Jun 21 2019 Radar continues to show weaker cells across the west at this time and primary cell over the north central exited southeast Wheeler County. Convection to increase in coverage toward midnight as a series of disturbances moving through flow carry showers and thunderstorms northeast through daybreak Saturday. && .SHORT TERM...(This evening through Saturday night) Issued at 330 PM CDT Fri Jun 21 2019 Two areas for potential severe weather this afternoon and tonight. The first is up across ncntl Nebraska where the Pacific cold front has slowed allowing for moisture convergence, pooling and destabilization. SPC mesoanalysis suggested 1500 J/KG of CAPE with no cap or inhibition. Winds aloft at 500 mb are strong at 30-35kts which would support supercells. A 50 percent POP is in place in this area tonight for scattered thunderstorms, a few which could become strong or briefly severe. Large hail would appear to be the primary concern. The second potential area for severe weather is across swrn Nebraska but this area is post-frontal with northwest sfc winds. The SPC mesoanalysis would suggest the area farther south near Dodge City might be more favorable for storm development. Meanwhile, the HRRR shows storms firing on the Palmer divide in ecntl Colorado this afternoon which track east, generally remaining south of Nebraska this evening. POPs tonight across swrn Nebraska less than 50 percent suggesting scattered storm coverage. The rest of the forecast area tonight, Saturday and Saturday night is operating on a showers/isolated thunderstorm chance as cooler more stable air is in place or will overtake the area Saturday and beyond. An upper level low is predicted to develop across Nebraska this weekend which would support showers and isolated thunderstorms. The cold air aloft is impressive with h500mb temperatures dipping to -15C. The temperature forecast then follows the cooler bias corrected guidance blend for highs in the 60s and 70s and lows in the 40s and 50s. .LONG TERM...(Sunday through Friday) Issued at 330 PM CDT Fri Jun 21 2019 The extended forecast continues on track and the models are in good agreement building an upper level ridge into New Mexico, ern Colo, KS and Nebraska. Winds aloft at 500mb weaken to less than 20kts Tuesday night signaling a summer pattern. There is still an isolated thunderstorm chance Wednesday and beyond but storms will be brief and likely become outflow dominant. Rain chances diminish Sunday afternoon as an upper low lifts into ncntl Nebraska. Temperatures warm Monday and increase throughout the week. A check on moisture suggests the rich moisture across KS and the South will move north through the Missouri river basin and remain mostly east of western Nebraska. The models show a steady rise in dew points to the mid and upper 60s across wrn Nebraska by Wednesday. The concern with the dew points is that the 70-plus dew points across the South will creep west into wrn and ncntl Nebraska. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 615 PM CDT Fri Jun 21 2019 Post frontal conditions are expected across all terminals through the 00z TAF cycle. The front has hung up just east of a KBBW to KONL line where one stray thunderstorms has developed. Into the overnight we expect a general increase in showers and thunderstorms across the outlook area. Heavy rainfall may reduce visibility in the strongest storms withe MVFR or lower ceilings. We anticipate that the activity will taper off early Saturday morning. Overall forecast confidence is strong, though short fused updates to the forecast may be needed depending on convective trends. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Keck SHORT TERM...CDC LONG TERM...CDC AVIATION...Jacobs
Area Forecast Discussion
National Weather Service Louisville KY
1018 PM EDT Fri Jun 21 2019 .Forecast Update... Issued at 1020 PM EDT Fri Jun 21 2019 Have been waiting to see evidence of a wake low, with south to southeast winds behind the active convection we had earlier. It`s starting to show on the Kentucky Mesonet with a band of southeasterly winds from western KY to Owen county. SDF gustied to 25 knots. Have updated the grids for this as well as will be cancelling the watch for the rest of the counties very shortly. Issued at 740 PM EDT Fri Jun 21 2019 Will be clearing some counties from the watch as the main line pushes through the region. We could see some redevelopment of storms behind it, but they likely would be elevated. Seeing good progress of the merger of the two lines of storms as they move into our BWG counties. Line closer to SDF does not look as intense, again as it moves into the drier surface air. Latest RAP mesoanalysis shows the instability gradient right along the line where our downstream watch box is. Issued at 620 PM EDT Fri Jun 21 2019 Northern side of the storm line is fairly healthy, despite moving into a less favorable environment. Decided to go ahead and expand the watch eastward, and with plenty of instability still to work through in southern KY, expect a better chance of severe weather all the way to the Lake Cumberland region this evening. Do have an odd shaped eastern extent, mostly because of the geography of the counties. Issued at 420 PM EDT Fri Jun 21 2019 Seeing the north/south oriented part of the line entering the Wabash now start to weaken with regard to lightning and cloud tops and a lack of wind/wind damage reports. The southern part of that line is becoming more robust however, with cellular activity showing some much colder cloud tops on latest IR imagery. Will follow this part of the line downstream into our forecast area and after coordination with SPC decided on a watch. Kept the Louisville metro out of this watch...given that weakening line. A second MCS is moving in from southeast MO and we will have to watch to see how that interacts with the first line. Models have been pegging that part of the line to stay stronger farther into our area later this evening, but expect the first wave to stabilize the lower levels. We can readjust the watch area later as we see how that interaction plays out. && .Short Term...(This evening through Saturday) Issued at 315 PM EDT Fri Jun 21 2019 ...Strong to Severe Storms Likely This Evening Through Tonight... A complicated forecast is in store for the short term. Regional radars and GOES-satellite reveal two distinct MCSs across central IL and central MO at this hour. These MCSs are riding along a warm front and instability gradient which is beginning to advect into our region. These MCSs should continue to follow along the front and begin to take a dive to the southeast here soon. The latest high-res models have not handled the MCS in central IL very well. Most have had it weakening significantly as it progresses eastward, however, it has managed to maintain itself longer than what they predicted. It is noteworthy that over the last 30-60 minutes, cloud tops have started to warm, lightning activity has decreased, and radar imagery doesn`t look as impressive compared to earlier in the day. Additionally, appears the severe potential with the MCS has been at a minimum over the last hour, as observations in the path of it have generally reported sub-severe winds. This may be due to a frontal inversion that has kept the strongest winds from mixing down to the surface. As this MCS approaches our region, the northern portion of the MCS should remain sub-severe, though it`s tough to say whether or not southern portions of the line will be capable of sporadic severe winds when it arrives since theoretically there should be less CIN in those areas with it being in close proximity to the warm front. Based on some rough timing estimates, think this line will begin entering our CWA (Dubois County, IN) around 21z, and then arriving to the Louisville/Bowing Green Metro areas around 22z-00z, and then arriving to the Lexington metro area by 00z-02z, if it holds together. The second MCS over MO is the one more likely to produce our severe weather based on the latest high-res guidance. This second MCS will be on the heels of the first, so we may see a slight break in the action, but it should quickly fill in. The warm front/instability gradient will continue to advect eastward into our region out ahead of the second MCS, which will aid in destabilizing the atmosphere even more. The big caveat to severe weather potential in our region is if the first MCS slows the advancement of the warm front and stabilizes the atmosphere ahead of the second MCS. Given that most guidance weakens the first MCS in central IL significantly and does not have it impacting our region, they result in a more unstable atmosphere ahead of the second MCS in MO, so they may not have the best portrayal of environmental conditions. Still, given the consistency in guidance to destabilize things quickly ahead of the second MCS, and a 30-40kt LLJ pumping in moisture/higher theta-E air from the southwest, will continue to advertise likely severe weather across the region, with the highest chances generally along and west of the I-65 corridor. Damaging straight line winds will be the most likely threat with the line, though brief isolated tornadoes will be possible within bowing segments and embedded mesovortices. The potential for yet another MCS (#3) could occur after midnight, bringing additional showers/storms and potential severe weather. We may finally start to dry out late tomorrow morning into the afternoon. Confidence in this third MCS remains low, but is something to watch. Given that our area will experience multiple rounds of heavy rainfall, and most area creeks/rivers/streams are still running high, will go ahead and put out a flash flood watch for much of southern Indiana and central Kentucky. This watch will run through tomorrow morning, but it may need to be expanded in time through the weekend if confidence increases in additional rounds of rain. .Long Term...(Saturday night through Friday) Issued at 325 PM EDT Fri Jun 21 2019 Saturday Night - Monday... An active weather pattern looks to continue through early next week. Saturday night a weak sfc boundary over the area combined with upper level shortwave activity and plenty of instability will provide focus for showers and storms. Strong storms are possible Sat evening before the environment becomes more elevated later Sat night into Sun morning. After a morning storm complex on Sun, we should see a break in convection for a large chunk of the day with an upper level ridge axis passing through. However, plenty of instability is expected to build Sun afternoon and could kick off scattered showers and storms especially along any left over boundaries from morning storms. Scattered showers and storms will likely continue into Sun night. Monday an upper level trough and cold front will approach the region. This should bring a better chance for showers and storms and possibly a more organized threat for some of those to be strong to severe with bulk shear values of 25-35 kts and CAPE values of 1500-2500 j/kg. The cold front passage is expected Mon evening. Temperatures will be in the 80s for highs Sun/Mon with Sun being the hotter day under the upper level ridge. Low temps should range through the upper 60s to low 70s. Tuesday - Friday... A few showers/storms may linger over east central KY on Tues before the area goes dry. A period of mainly dry weather is expected Tues- Fri as upper level ridging builds in over the southern U.S. A few small chances for diurnally driven storms may exist during the afternoon/evening hours each day next week, but mainly dry weather is anticipated. A slow warm up is expected with temps starting in the mid 80s for highs on Tues and increasing to the upper 80s to around 90 for highs by the end of the work week. && .Aviation...(00Z TAF Issuance) Updated at 735 PM EDT Fri Jun 21 2019 Line of storms approaching SDF/BWG this hour. Will see gusty winds at both terminals as those storms move through. Thunder will last an hour or two behind this line as it continues heading southeast. Will watch for redevelopment overnight, but confidence in individual locations is fairly low. Will have a longer period of vicinity showers and probably some brief periods of thunder into the morning hours as a low-level jet tries to establish itself. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Flash Flood Watch through Saturday morning for INZ076>079-083- 084-089>092. KY...Flash Flood Watch through Saturday morning for KYZ023>036- 038>042-045>049-053>057-061>067-070>078-081-082. && $$ Update...RJS Short Term...DM Long Term...AMS Aviation...RJS
Area Forecast Discussion
National Weather Service Morristown TN
953 PM EDT Fri Jun 21 2019 .DISCUSSION... Large bowing MCS continues to work east across Middle TN and southcentral/southeast KY this evening. Out ahead, a warm front and consequent swly moisture advection continue to move into the TN Valley at this time. Thus, am expecting continued elevated CAPE levels regionwide, with the most unstable regions along/west of the I75 corridor tonight. The primary threat tonight will be damaging winds along/ahead of the passing MCS, some gusts as high as 60-70mph are expected. Also, backed flow out ahead of the front could enhance localized llv helicity, therefore a few embedded tornadoes cannot be ruled out. All said, looking at a stormy night across east TN and southwest VA/NC with timing as follows. Latest HRRR runs favor intrusion of the bowing line across the Plateau by 11PM, then moving east/southeast approaching the I75 corridor by around midnight, before moving further east across the I81 corridor into the foothills/mountains closer to the 2AM timeframe. Severe Thunderstorm Watch 419 continues through 2AM. As for the fcst, tweaked pops to align with current coverage westward, as well as latest CAMPOP trends over the next 3-4 hours. No other sig changes needed/made with this update. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 73 90 73 89 / 80 50 30 30 Knoxville McGhee Tyson Airport, TN 70 87 70 87 / 80 50 50 50 Oak Ridge, TN 70 87 70 87 / 80 50 50 30 Tri Cities Airport, TN 63 82 65 83 / 80 50 60 50 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...None. TN...None. VA...None. && $$ CDG
Area Forecast Discussion
National Weather Service Nashville TN
1014 PM CDT Fri Jun 21 2019 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Will be clearing the last row of counties in the next 10 min or so. mostly light rain showers continue with a few embedded heavier showers and isol tstms. We are still looking at another possible system moving down as we move toward sunrise. Latest Hrrr data, note that this model handled the last system rather well, indicates that the next system will be knocking on the door around 12z. Day 2 outlook does indicate a slight risk for our eastern half with a marginal risk elsewhere. However, much of the atmosphere is already worked over so this next event should not come close to rivaling what have experienced over the last several hours. Will double check those temps and make sure they are on track. updated zones will follow. && .AVIATION... 00Z TAF DISCUSSION. MCS on its way to the mid state at this hour. Should begin to feel the impact near CKV within the next 2-3 hours. Most areas will get 20-30 kt winds with gusts between 30 and 40kts. Isolated to scattered area will reach and perhaps surpass severe limits. The showers and tstms will traverse the entire mid state with the activity reaching the BNA area between 1z and 3z and then CSV between 3z and 6z. Some decrease in low level forcing will occur by the time the complex reaches the CSV area. However, Momentum, couple with available convective fuel will allow the severe potential and high winds to continue. Another system could potentially roll through around sunrise. This second system looks a bit iffy at this time however. Otherwise, should be relatively quiet aft 15z. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......21 AVIATION........21
Area Forecast Discussion
National Weather Service Pueblo CO
908 PM MDT Fri Jun 21 2019 .UPDATE... Issued at 903 PM MDT Fri Jun 21 2019 Expired watch 217, will keep watch 220 in place until 11 pm for Kiowa County. Storms have weakened somewhat as of 9 pm, though still getting some fairly strong outflow gusts (61 kts at KLHX) along Highway 50, well south of the storm cores. UPDATE Issued at 812 PM MDT Fri Jun 21 2019 Extended Svr Tstorm Watch 217 until 9 pm to account for storms currently moving through the county. Main threat looks to be severe wind, as organized updrafts seem to be quickly disrupted by deepening nly flow, though some marginally severe hail may still be possible. UPDATE Issued at 533 PM MDT Fri Jun 21 2019 Updated forecasts to add severe thunderstorm watch 420 to Kiowa County, as activity farther northwest may brush by later this evening with front dropping south. Even had a run of the HRRR with storms farther south near Lamar, though latest run has backed off, keeping everything from Kiowa County northward, so will await further developments before extending watch south. && .SHORT TERM...(This evening through Saturday) Issued at 305 PM MDT Fri Jun 21 2019 ...Active weather pattern over the next 24 hours with severe thunderstorms for the plains and snow for the mountains... Front has been slow to lift back northward across southern CO today allowing surface dew points to stay in the 50s and even around 60 across the far eastern plains. This has allowed sfc based CAPE values to creep up over 1000-2000+ J/kg across the southeast plains though stout cap has kept thunderstorms from initiating across southern portions of the area. It will be a different matter for El Paso county as high res models continue to show thunderstorms initiating over the Pikes Peak region and moving eastward through the afternoon and early evening. Impressive deep layer shear is in place and once instability is realized (1000-1500 J/kg) should see isolated supercell thunderstorms develop along the Palmer Divide and move eastward. Am somewhat concerned that higher dew points farther south could lead to an increased severe threat for one tier of counties farther south (including Crowley and Kiowa and possibly Pueblo)...but HRRR has been solid on keeping the majority of the stronger activity across El Paso, Lincoln, Douglas and Elbert counties. NAMNest has trended southward with Kiowa county getting in on the action towards 02-03z. For now, Severe thunderstorm watch is already in place for El Paso county through 8 PM. Across the remainder of the mountains should see shower and thunderstorm activity increase as energy in the base of the upper trof axis rotates through western CO. Snow levels will drop overnight down to 10.5kft...with an inch or two of snow possible across the higher elevations of the Sawatch and Mosquito ranges overnight. Amounts appear too light at this point to warrant any Winter weather highlights. Meanwhile, cold front will blast through the southeast plains this evening with gusts up to 50 mph possible behind the front, especially where enhanced by convective outflows from the north. Could see a strong storm or two develop along/behind the front this evening, but again high res models do not look too excited about this potential with HRRR keeping activity to the north. Low levels cool and saturate with showers developing behind the front after 06z which continue into the morning hours. Saturday looks like a typical Day 2 Severe weather set up with upslope flow across the plains. Cool and stable conditions can be expected through the morning...but with strong forcing from the upper trof swinging through, should see sufficient cooling aloft for scattered thunderstorms to develop over the mountains which move off into the adjacent plains during the afternoon. Deep layer shear will be sufficient for a severe potential but CAPE may be the limiting factor. SPC Day 2 outlook has Marginal threat for severe thunderstorms tomorrow which still looks good given the uncertainty. Best bet to see severe thunderstorms would be the I-25 corridor and lower eastern slopes of the southeast mountains where elevated heating is most likely to break the cap. Raton ridge area and southern portions of the southeast plains will also be another risk area. Large hail and damaging winds will be the primary storm threats, though an isolated tornado would not be out of the question if we can get rid of the CIN. Will also need to monitor burn scars closely for a flash flood threat...though certainty is too low at this point to go out with a flash flood watch. -KT .LONG TERM...(Saturday night through Friday) Issued at 305 PM MDT Fri Jun 21 2019 Saturday night-Sunday night...Latest models remain in decent agreement of an unseasonably strong upper trough lifting out across the Rockies through the day Sunday, though still indicate some differences on how far south the associated wrap around precipitation will be across eastern Colorado on Sunday. At any rate, should see scattered to numerous showers and storms across the higher terrain Saturday afternoon spreading north and east across the I-25 Corridor through the far southeast Plains Saturday night. With strong lift associated with the passing system, storms could be on the strong side through the evening, with locally heavy rain and hail possible. Latest guidance continues to indicate snow levels falling to around 9,000 feet through early Sunday morning, supporting a few inches of accumulating snow across the higher peaks, mainly above 10,000 feet across the central mountains and the Pikes Peak massif. With moderate northwest and subsidence developing behind the passing trough on Sunday, believe the best chances of lingering showers and storms will be north and east of the Highway 50 Corridor on through the day on Sunday. With the unseasonably cool system moving across the region, overnight lows look to be in the the 30s and 40s across the area Saturday night and Sunday night, with the potential for near freezing temperatures in the San Luis Valley Sunday night/Monday morning. Highs on Sunday will continue to be well below seasonal levels in the 60s and 70s across the Plains and mainly 40s and 50s across the higher terrain. Monday-Friday...A warmer and drier weather pattern remains in the offing as a large ridge of high pressure is forecast to build into the Rockies through the beginning of the week and then becomes entrenched across the Rockies into the end of next week. This will bring steady warming with temperatures back to and slightly above seasonal levels, with more isolated diurnal convective activity. There may also be the potential for convection along a dryline wavering across the far southeast Plains through the middle of the week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 305 PM MDT Fri Jun 21 2019 Isolated to scattered thunderstorms will be most likely to affect the central mountains and Pikes Peak region this afternoon with the potential for hail and damaging winds at KCOS. Most of the high res models keep activity just north of the KCOS terminal. Cold front will drop through KCOS and KPUB by 01z with gusts to around 40-45 kts possible with Fropa. KPUB is more likely to remain dry through the evening. Low clouds will fill in and lower across the plains after 06z with the potential for -SHRA and MVFR to IFR conditions towards morning. Clouds will persist through the morning before breaking with a better chance of afternoon thunderstorms after 20- 21z. For KALS...will see gusty southwest winds continue into early evening before winds decrease overnight. Southwest winds will pick up again on Saturday though will not be as gusty as today`s. Conditions will remain VFR. -KT && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...PETERSEN SHORT TERM...KT LONG TERM...MW AVIATION...KT
Confidence in the above aviation forecast discussion is
Area Forecast Discussion
National Weather Service Tallahassee FL
850 PM EDT Fri Jun 21 2019 .UPDATE... Forecast remains on track this evening with just only very small isolated storms lingering that will dissipate over the next hour or two. && .PREV DISCUSSION [718 PM EDT]... .NEAR TERM [Through Tonight]... The main concerns this evening will be scattered thunderstorms and elevated heat indices/apparent temperatures. A weak surface trough was located invof the I-10 corridor, in addition to a sea-breeze front in the southeast big bend, both serving as triggering mechanisms for showers and scattered thunderstorms. The 18Z TAE RAP sounding indicated Mixed Layer CAPE over 3k J/kg and Precipitable Water values near 1.9 inches. Mid-level lapse rates were around 7C/km and Downdraft CAPE was over 1.2k J/kg. The potential for robust convection is there given these indices, however Bulk Shear Shear (0-6 km) of only around 10 knots and a cap around 700 hPa will limit both the coverage and intensity of thunderstorms. At this time, highest precip potential in the chance category will be near I-10 into the big bend through early tonight. A couple pulse-type severe thunderstorms are possible with damaging wind the main threat. Turning our attention to the heat, apparent temperatures/heat index values as of late afternoon were elevated across the region, with values within a couple degrees of 105, but just shy of heat advisory criteria at most locations, which is 108 degrees. With temperatures near maximum values for the day and dew points beginning to fall, heat indices should begin to decrease, and the current forecast reflects this thinking. Another warm and humid night is in store with a slight chance of a shower and low temperatures generally in the middle 70s. .SHORT TERM [Saturday Through Sunday Night]... Deep layer ridging and dry air will cover much of the Tri-State region through the weekend. The main exception will be across south-central Georgia where scattered showers and storms will be more likely as an upper level wave links up with lee troughing. Otherwise, highs will climb into the middle and upper 90s with heat indices well over 100 degrees. .LONG TERM [Monday Through Friday]... Multiple shortwaves are forecast to move across the northern Gulf Coast next week. These waves will all superposition over the eastern GOMEX and then retrograde as a TUTT later in the week. The result will be a week of unsettled weather, with higher than average rain chances. High temperatures should remain in the lower 90s which is near normal. .AVIATION... [Through 00Z Sunday] Convection has wound down for the evening and VFR conditions should continue for the next few hours. Around 06-09Z, MVFR cigs are expected to develop and could linger over the region into the late morning-early afternoon hours on Saturday. Tomorrow afternoon chances for thunderstorms are 30% or less at all TAF sites, so no TSRA included in this TAF package. Light to moderate southwest winds are forecast through the period. .MARINE... Winds and seas are forecast to remain below headline levels over the next several days. As is typical this time of year, expect upticks in winds and chop near the coast each afternoon. .FIRE WEATHER... Drier conditions and below average rain chances are forecast over the next few days. Hazardous fire weather conditions are not expected, however. .HYDROLOGY... Low rain chances will result in no flooding concerns through early next week. By Tuesday, the pattern will shift to a wetter regime with widespread rainfall totals of 1-3" forecast through the end of next week. .SPOTTER INFORMATION STATEMENT... Spotter activation is not requested. However, spotters are always encouraged to safely report significant weather conditions when they occur by calling the office or tweeting us @NWSTallahassee. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 76 94 74 96 74 / 10 20 10 10 0 Panama City 78 88 79 89 78 / 10 10 10 0 0 Dothan 76 94 73 95 73 / 20 30 10 10 0 Albany 76 93 74 94 74 / 20 30 20 20 10 Valdosta 75 94 73 96 74 / 20 20 20 10 0 Cross City 75 91 74 93 74 / 0 10 10 10 0 Apalachicola 79 89 77 90 78 / 0 0 0 0 0 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk until midnight EDT /11 PM CDT/ tonight for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton. GA...None. AL...None. GM...None. && $$ UPDATE...Nguyen NEAR TERM...LF SHORT TERM...Harrigan LONG TERM...Harrigan AVIATION...Nguyen MARINE...Harrigan FIRE WEATHER...Harrigan HYDROLOGY...Harrigan