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

Area Forecast Discussion
National Weather Service Burlington VT
1039 PM EDT Sun Jun 17 2018 .SYNOPSIS... An active weather day is anticipated on Monday with several rounds of strong to severe convection, along with very warm and humid conditions. Temperatures are expected to reach the mid to upper 80s with localized valley locations near 90, combined with humidity values will create heat index values well into the 90s on Monday. Thunderstorms will be capable of producing very heavy downpours with potential for isolated flash flooding, gusty winds, and frequent lightning. The thunderstorm threat will end by late evening on Monday with much cooler and drier air arriving on Tuesday. && .NEAR TERM /THROUGH MONDAY NIGHT/... As of 1033 PM EDT Sunday...Late this evening, GOES-16 IR imagery continue to indicate abundant cirrus/cirrostratus settling NW- SE across the North Country in anticyclonically curved flow aloft. This will help mitigate radiative cooling effects, keeping overnight lows in the mid 60s to lower 70s (warmest in the Champlain Valley). Dewpoints haven`t risen much yet, and won`t until after sunrise Monday. Looking at 2-m dewpoints ranging from the mid-upr 40s across VT, to the lower 60s across the St. Lawrence Valley, with continued S-SW flow expected overnight. There are some modest 700-500mb height falls overnight, and this will allow for some possible light rain showers along the Intl Border. Maintained 20-40 PoPs for nrn counties thru 12Z Monday. Previous Discussion...Water vapor shows mid/upper level ridge axis across the mid Atlantic/eastern Great Lakes with fast westerly flow aloft with embedded s/w`s and ribbons of moisture on northern periphery of ridge. For tonight, watching cluster of storms over the northern Great Lakes which are progged to move quickly in the western flow aloft over southern Canada. Latest guidance continues to support threat of showers with embedded rumbles of thunder, near the international border aft midnight tonight. RAP shows sfc based cape values of 400 to 800 j/kg, along with weak ribbon of mid level moisture and enhanced lift couplet impacting our northern cwa with embedded s/w energy. Given time frame and moving into subsidence from ridging, would anticipate a decaying mcs with area of rain and embedded lightning. Temps with mid/upper level debris clouds, increasing sfc dwpts, and southerly winds will be very mild tonight. Thinking mid/upper 60s mountains to lower 70s slv/cpv with a muggy feel to the airmass. Monday/Monday Night...An active period of weather is anticipated with several rounds of strong to severe thunderstorms with localized heavy rainfall and gusty winds, along with very warm/humid conditions. We are thinking several rounds of convection is likely with first associated with pre-frontal trof/terrain induced btwn 16- 20z. Latest NAM3/BTV 4km and NSSL WRF develop sfc based instability values of 1800 to 2200 j/kg by 16z with a ribbon of enhanced 850 to 700mb winds of 40 to 50 knots, creating 0 to 6 km shear values of 35 to 45 knots. The limited factor will be the lack of significant synoptic scale forcing/convergence so anticipating scattered to numerous pulse type storms with isolated severe likely given instability. The primary threat would be localized damaging wind gusts, but given EL>40 kft and large CAPE profiles a few stronger updrafts will be capable of producing 1 inch hail, even with high WBZ/Freezing levels. SPC has upgraded our day2 outlook to place our entire cwa in slight risk. Given the warm cloud depths>12kft and pw`s between 2.0 and 2.25 very high rainfall rates of 1.0 to 1.5 inches per hour are likely. Storm motion vectors show individual storms moving from west to east, with some potential for back building given the low level jet orientation. Feeling is the first round the threat for flash flooding will be limited, but set the stage for additional threat as line of storms develop during the late aftn/early evening hours. Additional thunderstorms are anticipated btwn 21z and 01z associated with cold front and better short wave energy. However, the uncertainty will be amount of clearing/sfc heating from earlier convection and how much instability can develop before fropa. Current guidance suggests sfc based CAPE values will recover between 1500-1800 j/kg with 0 to 6 km shear values of 35 to 45 knots to support a broken line of strong to severe thunderstorms. Given the wind profiles and thermal dynamics, thinking strong/gusty winds will be primary severe threat with isolated to scattered power outages/trees down possible. Storm vector analysis show individual cells moving west to east at 25 to 30 mph, as entire line of storms tracks slowly from nw to se across our cwa. Given the 925mb to 850mb jet of 35 to 40 knots, paralleling approaching boundary, some potential for back building/training convection exists, which may create isolated flash flooding. Pw`s remain near climo max for the date, with values btwn 2.0 and 2.25 with enhanced pooling ahead of approaching boundary. This supports the idea of additional very heavy rainfall rates with a greater potential for isolated flash flooding, especially over areas that receive earlier rainfall from pre-frontal trof. Its been noted the differences in instability between the gfs and wrf models is from wrf`s showing sfc dwpts in the mid 70s, resulting in higher cape values, while gfs shows sfc/2m temps only in the upper 70s to mid 80s, resulting in less cape. Taking an average shows values between 1500 and 2000 j/kg with higher pockets. Next concern is heat index values for Monday, as temperatures reach the mid 80s to lower 90s with dewpoints approaching 70f. 925mb temps are 1 to 3 degrees warmer on Monday with values near 24c, but expecting more clouds/storms and less mixing due to saturated column. These high temps with expected dwpt values create max heat index readings mainly btwn 90 and 95 degrees btwn 11 AM and 2 PM on Monday, with warmest values of 95 to 98 in the urban areas of the southern CPV and lower ct river valley. Therefore will issue heat advisory for Eastern Essex NY, Western Addison/Rutland/Chittenden and Windsor counties in VT. Further north the uncertainty on clouds and impacts on temps, along with only a few isolated areas touching 95f for an hour, have held off on issuing heat advisory. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 342 AM EDT Sunday...By Tuesday morning, the front will have pushed through the forecast area and surface high pressure centered over southern Ontario will build in to the North Country. The arrival of drier air behind the front will bring a return to more seasonal weather with highs in the 70s Tuesday and a noticeable decrease in the "mugginess". Should see plenty of sunshine during the day, and mostly clear skies overnight will allow nighttime lows to cool to the lower to mid 50s in most areas. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... As of 342 AM EDT Sunday...The long term forecast looks fairly benign overall with no major features progged to move through New England through the end of the work week. A broad trough will remain over eastern Canada, with multiple embedded shortwaves moving through and attempting to amplify the upper-level pattern. The net result of this will be persistent dry, seasonally warm northwesterly flow with some mild cool downs as shortwaves bring shots of cooler air southeastward. High temperatures will stay in the low 70s to low 80s range Wednesday through Friday, and the dry air mass in place will allow lows to reach the 40s to low 50s each night. For now have included VCSH instead of prevailing rain and thunderstorms, just want to see how things begin to develop tomorrow first. Overall fairly high confidence in the larger scale pattern through Friday, but uncertainty starts to arise looking into next weekend as models struggle to handle the evolution of the upper level pattern. Initial indications look to trend warmer and more humid going into the weekend, with the potential for increasingly active weather Sunday/Monday. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... Through 00Z Tuesday...High clouds streaming over the area this afternoon will thicken and lower through the overnight hours as an increasingly moist, unstable air mass moves in. A cluster of storms over the northern Great Lakes area will approach the forecast area overnight as it moves eastward, but expecting this system to skirt just to our north. After 12Z, increasing instability will lead to pop up showers developing, particularly over mountainous terrain. Between 15Z and 18Z, expect coverage of showers to increase some, particularly in northern areas of the forecast area. The better chances of more widespread, organized convection will be after 18Z tomorrow, but some areas could see some showers with heavy rain before 18Z. Visibilities will be reduced in heavy showers, but expecting ceilings to remain above 5000 ft. Southerly/southwesterly winds under 10 kts will ramp up to 10 - 15 kts after 12Z, with some gusty winds possible in any storms that develop. Could also encounter some areas of turbulence tomorrow due to the thunderstorms, particularly in and around terrain. Outlook... Monday Night: VFR. Chance SHRA, Slight chance TSRA. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. NO SIG WX. Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Slight chance SHRA. Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. && .HYDROLOGY... Scattered to numerous showers and thunderstorms are expected to develop midday Monday and continue into Monday evening. The combination of precipitable water values of 2.0 to 2.25 inches and storm motions supporting some training of convection, supports the threat for isolated flash flooding. Given the available moisture in the atmosphere, any storms will be capable of very heavy rainfall rates of 1 to 1.5 inches in an hour, which over terrain or urban areas could cause isolated flash flooding. Given the very recent dry weather widespread/large stem river flooding is not anticipated, but sharp rises on smaller streams in complex terrain where multiple rounds of storms occur is possible. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Heat Advisory from 11 AM to 6 PM EDT Monday for VTZ005-009-011- 012. NY...Heat Advisory from 11 AM to 6 PM EDT Monday for NYZ035. && $$ SYNOPSIS...Taber NEAR TERM...Banacos/Taber SHORT TERM...RSD LONG TERM...RSD AVIATION...Neiles HYDROLOGY...Taber
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
953 PM EDT Sun Jun 17 2018 .SYNOPSIS... Hot high pressure will build atop the region through the middle of the week. Scattered afternoon and evening thunderstorms are expected each day, focusing over the mountains. Moisture will increase towards the end of next week as a weak frontal boundary sags toward the area. && .NEAR TERM /THROUGH MONDAY/... As of 945 PM EDT Sunday: Some minor tweaks to hourly trends but otherwise no significant changes for the late evening update. Otherwise, high pressure will dominate the weather for the near term and beyond with a Bermuda high off the coast and an upper ridge over the Eastern CONUS. The only change for the next 24 hours will be an increase in the strength of a surface trough east of the Appalachians that modifies the otherwise broad area of high pressure over the SE CONUS. This weak trough will modify surface wind direction, but do little else, with winds remaining light and somewhat variable. Moisture and unseasonably warm to hot afternoon temperatures will continue with heat indexes reaching the mid to upper 90s this afternoon and on Monday. Warm temperatures aloft will limit CAPE development in the afternoons, and some increase in the strength of the capping inversion is also anticipated. This will limit intensity of thunderstorm activity and confine initiation to the mountains. Any storms that do develop have the potential for brief low-end severe wind gusts. CAMs mostly have convective showers confined to the mountains, with the HRRR having a couple spots of convection in piedmont areas with weak updrafts. Have, thus, de-emphasized thunderstorms in piedmont areas this afternoon and tomorrow. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/... As of 215 PM Sunday: Strong upper ridging will remain in place across the western Carolinas and northeast Georgia through Tuesday. Winds will be very light up the column and this minimal steering flow should keep convection mainly over mountain sections, where slow-movers will create an isolated heavy rainfall threat with any downpours that develop. Additional triggering will be possible east of the mountains in weak lee trough convergence, but coverage will be more isolated in nature there. Very warm mid-level temps should keep severe weather to a minimum. Expect plenty of 100 to 104 heat index values east of the mountains, and a few piedmont locations could flirt with 105 if dewpoints do not mix sufficiently. Height falls across the northern tier will improve the westerlies slightly over the region on Wednesday. Weak vorticity lobes riding over the southeast ridge could aid diurnal triggering Wednesday afternoon, but continued warm mid-level profiles will inhibit most of the severe potential. Westerly downsloping will improve warming east of the mountains, and there could be slightly better dewpoint pooling south of the frontal boundary through the Virginias late Wednesday. Expect another afternoon of heat index values rising into the 100 to 105 range. The HWO mention will continue even though Heat Advisories are currently looking a bit marginal. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... As of 200 PM EDT Sunday: The medium range remains dominated by hot and humid conditions and a diurnal pattern of showers and thunderstorms each day. By the time the extended period picks up 00Z Thursday, the strong upper ridging over the SE CONUS will be in the process of waning while a large upper trough digs into the eastern CONUS. A frontal boundary will slowly sag southward as this trough descends, finally making it into our area by Friday. Some moisture will accompany the boundary, which will serve as a focus for diurnal convection, especially Friday and Saturday. Guidance then suggests that an upper low/trough will swing into the central Plains and drive another frontal boundary towards the area over the weekend. This should enhance the pattern of diurnal showers and thunderstorms, increasing not only the likelihood but also the coverage through the end of the week and into the weekend. Temperatures will remain hot on Thursday with dew point likely only mixing out to the highs 60s at best in the afternoon hours, meaning another day of heat indices flirting with advisory criteria. Heights will fall just enough on Friday through the weekend for max temps to drop to within 5 degrees of normal. Min temps will remain above average through the period. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... At KCLT and elsewhere: No changes for the KCLT TAF for the 02z AMD. VFR through the period, except for mountain valley fog expected again in the morning and low VFR fog also possible at KAVL/KAND/KHKY. Another round of mainly mountain convection expected Monday afternoon/evening and have introduced PROB30 for KAVL. Winds generally SW 5kt or less through the period. Outlook: Typical summertime potential for diurnally-driven showers and thunderstorms will persist into midweek, thanks to a large upper level ridge, bringing hot and humid conditions. Some morning fog will also be possible in the mountain valleys and over lakes each day. Chances for precip look greater late in the week as the ridge begins to break down. Confidence Table... 02-08Z 08-14Z 14-20Z 20-00Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 100% High 100% High 100% KAVL High 100% High 83% High 100% High 100% KHKY High 100% High 100% High 100% 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...Carroll NEAR TERM...TDP/WJM SHORT TERM...HG LONG TERM...Carroll AVIATION...TDP/WJM
Area Forecast Discussion
National Weather Service Jacksonville FL
713 PM EDT Sun Jun 17 2018 .UPDATE...Radar shows scattered convection which should gradually diminish. May see some flare up with converging outflow boundaries Suwanne Co to Baker Co. for an hour or two. Otherwise...partly cloudy skies Tonight with low temps near our current forecast lows. Latest hi-res guidance not showing much precip after midnight thru mid-morning made some adjustments to hourly POP/weather grids for this period. && .AVIATION...VFR conditions through Tonight. Latest HRRR suggests some lower clouds possible around coastal TAF sites...but SREF not showing this. Put in a 4hr TEMPO for MVFR CIGS 10z-14z at KSSI and KSGJ for now. Limited VCTS tomorrow to just KVQQ and KGNV with minimal TSRA coverage anticipated at TAF sites further east. && .MARINE...No significant changes planned for next CWF issuance. High pressure to the north will continue the east to southeast winds through Monday. Surface ridge pushes south of the area by midweek resulting in an offshore flow pattern again interrupted by daily seabreezes. Low wind speeds and sea heights are expected over the next few days. Rip Currents: Moderate risk on Monday with onshore winds. && .PRELIMINARY POINT TEMPS/POPS... AMG 71 91 71 92 / 20 50 20 40 SSI 76 86 75 89 / 10 20 10 20 JAX 73 90 72 92 / 10 20 10 40 SGJ 75 87 72 89 / 10 20 0 30 GNV 72 91 71 92 / 30 40 20 40 OCF 72 92 71 92 / 30 30 20 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Wolf/Elsenheimer/Bricker
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
805 PM CDT Sun Jun 17 2018 .UPDATE... 804 PM CDT Quiet but humid, warm evening across the CWA. Rain-cooled outflows from earlier did push some temperatures down (e.g. 82 in Morris), but also nudged up dew points in these areas. Can`t rule out some shallow fog in these areas overnight if it clears of cirrus. As for the prolonged effects of the heat, the urban heat island of Chicago and adjacent suburbs are doing well to retain the heat, with downtown, O`Hare, and Midway all at 88 degrees as of 8 pm. Early evening satellite imagery and 00Z upper air raobs indicate a series of short waves from the central Plains into northern Wisconsin with multiple areas of convection. One wave with a 1007 mb surface low is moving eastward in northern Wisconsin, and convection ahead of this has shown some cold pool push. Corfidi vectors for this activity are oriented more south-southeast, and there continues to be good surface and low-level moist flow into this so expecting to see that trend gradually play out. Some of this convection itself, or isolated convection developing ahead of this on outflow, could reach southeast Wisconsin after midnight. In addition, more convective activity favored across the Minnesota/Iowa border region late this evening could also advance into southern Wisconsin late tonight per analysis and support of convective-allowing models. This poses some concern for at the least outflow reaching into northern Illinois including Chicago into Monday morning, and even the possibility to bubble isolated storms. For now have just slightly expanded southward the early morning slight chance of storms, as confidence on this is low, but would at least expect some convective activity late tonight/very early tomorrow morning in southern Wisconsin. Forecast for Monday continues to look in good shape with the points noted in below AFD. Concerns for heavy rain potential Monday evening into the overnight are certainly there with 00Z raobs at MPX and OAX indicating over two inches of precipitable water, and a potential for west-to-east training setup with generally light propagating vectors off that development corridor. Uncertainties remain on just how quickly the frontal and post- frontal convection work their way into the CWA from the north on Monday evening, as well as some potential for pre-development with RAP soundings for tomorrow afternoon indicating the cap likely being close to being breached. MTF && .SHORT TERM... 228 PM CDT Through Monday... Second day of heat continues today across northern Illinois and northwest Indiana where temperatures have warmed into the low 90s with dew points in the low to mid 70s. This afternoon, an axis of convergence has developed from near Rutland, IL to near O`Hare and the north Chicago metro, possibly the result of differential heating from persistent thicker cirrus just northwest of that line. This convergent axis represents the most likely area to see an isolated shower or storm to develop this afternoon. A second area of convergence is noted from near Kankakee to Gary, IN. Recent AMDAR soundings out of Chicago indicate very weak if any CIN and RAP analysis shows in excess of 2000 J/kg MLCAPE over the forecast area. Despite the instability, lack of any synoptic scale ascent (soundings how more subsident conditions in place) should limit precip chances to stay fairly isolated along these areas of low level convergence. Will have to keep an eye on any outflow boundaries that may develop this afternoon as well. These slight precip chances will wane with sunset this evening. Overnight lows are only expected to be in the mid 70s with Chicago holding on to 80s in spots due to the urban heat island. Heat continues again on Monday and expect another day with temperatures into the low possibly mid 90s with dew points in the low to mid 70s. Heat indices are forecast to be in the 100 to 105 range again on Monday. Given this will be the third day of 100+ heat indices, have opted to continue the heat advisory despite the potential for falling just shy of the 105 criteria. The cumulative effects of the heat will continue to take a toll. Meanwhile, a cold front is progged to sag south across Wisconsin through the day tomorrow likely reaching the state line by late afternoon or early evening. Some models show outflow surging down the lake which may result in earlier relief from the heat for some locations near the lake if this occurs. Chances for showers and thunderstorms will increase through the afternoon as the front approaches. Dew points pooling into the mid 70s along and ahead of the front will contribute to moderately strong instability, though upper level flow continues to appear weak which may help to mitigate the threat for organized severe weather. Very heavy rainfall and pulse-severe appear to be a distinct possibility though. Deubelbeiss && .LONG TERM... 327 PM CDT Monday night through Sunday... Overview...Looking at a wet start to the week as a cold front/low pressure trough stalls over the forecast area Tuesday and Wednesday. Temperatures will vary widely Tuesday from lakefront temps around 70 to upper 80s and heat indices in the upper 90s south of I-80. We get a little relief from the heat mid week, but widespread precip is expected to return late in the week with a low pressure system. The front stalls over the southern portion of the forecast area Monday night. Temps north of the boundary will be in the mid 70s to low 80s away from the lake. Lakefront temps will be around 70 thanks to flow off of the lake, while areas south of I-80 will be in the upper 80s. Additional showers and storms are expected, and heavy downpours are likely with precipitable water values over 2 inches. 2 inches is an abnormally amount of precipitable water for this time of year. CAPE values are forecast to be around 1500 J/kg, but shear will be less than 20 kt. Therefore, a few storms may pulse up, but widespread severe storms are not expected at this time. Steering flow around 20 MPH will lead to slowly moving storms, so flash flooding may be possible if storms train. The boundary shifts south Wednesday as does the chance of showers and storms. Onshore flow continues leading to highs around 70 along the lake, but mid 70s to low 80s elsewhere. An upper level disturbance may trigger more showers and storms Thursday, but I have low confidence in timing and location. Temps will be similar to Wednesday. Widespread precip is more likely Friday as low pressure moves over Iowa. The low moves over the lake Saturday, and there may be more showers and storms Saturday. Temps continue to be near normal, but cooler near the lake. JEE && .CLIMATE... A record warm low is probable for Chicago for June 17. Here are the standing records for Chicago and Rockford: Chicago Rockford Sun Jun 17 Low 77 (1984) Mon Jun 18 High 98 (1954) 99 (1994) Low 77 (1921) 74 (1905) && .AVIATION... For the 00Z TAFs... Main forecast concerns center around the threat of thunderstorms with heavy rain, particularly very late Monday afternoon and into the evening as a cold front begins to drop over the area. The spotty showers and thunderstorms are quickly dissipating across the area early this evening. Overall, tonight into early Monday afternoon look quiet weather-wise. The only exception to this will be if some thunderstorm activity well to our northwest tonight tries to drive an outflow boundary and some isolated to scattered storms southward over the area by daybreak Monday. Currently confidence is this occurring is on the low side, so there is currently no mention of such in the TAFs, but this possibility will need to be monitored. Otherwise, expect another hot day with west-southwest winds gusting up close to 20 KT at times into the afternoon. Some isolated afternoon storms could again develop over the area Monday, as they did this afternoon, but the primary window for thunderstorms looks to be very late Monday afternoon into the evening (roughly 23z through 04z). This better chance of storms will be associated with a cold front, which is expected to shift over the terminals by early evening. In addition to the storms, expect a wind shift out of the north-northeast following the frontal passage. While the exact timing of storms into Monday evening is still a bit uncertain, it does appear that there could be a few hour period of storms. These storms are also likely to be prolific rainfall producers. So a periods of heavy rainfall with low visibilities possibly briefly under a mile will all be possible with these storms. KJB && .MARINE... 327 PM CDT Southwest winds continue until a front shifts down the lake Monday. Models differ on how quickly the front will progress, and I went with a slower solution. The front should clear the southern end of the lake Monday evening, and winds will be north to northeast 10-20 kt tonight. The front will stall over central IL and IN, while a high pressure ridge will stretch from the northern Great Plains through the northern Great Lakes into southeast Ontario. Light northeast winds are expected through much of this week. The next low will form over the Plains Thursday and is forecast to reach the lake Saturday. JEE && .LOT WATCHES/WARNINGS/ADVISORIES... IL...Excessive Heat Warning...ILZ014 until 7 PM Monday. Heat Advisory...ILZ003-ILZ004-ILZ005-ILZ006-ILZ008-ILZ010-ILZ011- ILZ012-ILZ013-ILZ019-ILZ020-ILZ021-ILZ022-ILZ023-ILZ032- ILZ033-ILZ039 until 7 PM Monday. IN...Heat Advisory...INZ001-INZ002-INZ010-INZ011-INZ019 until 7 PM Monday. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Pueblo CO
241 PM MDT Sun Jun 17 2018 .SHORT TERM...(This evening through Monday) Issued at 228 PM MDT Sun Jun 17 2018 South to southwest flow aloft will remain over the area tonight, ahead of an upper level low centered over northern NV. A disturbance will be slowly moving from northern NM, northeastward across southeast CO tonight. For this evening, the models have been consistent in showing the majority of precip from about the I-25 corridor counties and westward, with maybe some isold activity over eastern areas. The HRRR and NAM have been consistent in showing the highest precip chances this evening over the central mtns, the Pikes Peak region and maybe southward into Pueblo and Huerfano counties. QPF amounts in the GFS are higher than the NAM, and show from a couple tenths of an inch over Teller and northern El Paso county to around a half inch or a little more. Localized heavy rain will be a concern, especially over burn scars, and possibly urban areas. It looks like most of the precip will be over by about midnight, but there could be a few lingering showers over northern area into the late night. A strengthening surface low over the I-25 corridor of southern CO into this evening will cause strong southerly winds over the far southeast plains. Drier weather is expected for Mon, although there could be some isolated showers/tstms in areas mainly north of Highway 50. High temps on Mon are expected to be around to a few degrees above average, with upper 80s to mid 90s acrs the southeast plains, and upper 70s to lower 80s in the Upper Arkansas River Valley and the San Luis Valley. .LONG TERM...(Monday night through Sunday) Issued at 228 PM MDT Sun Jun 17 2018 Monday evening through early Tuesday...A lee surface trough will shift east across the southeast Colorado plains, pushing a front down the plains. Increased moisture behind the front and weak upslope flow could lead to the development of an isolated shower or thunderstorm along the Palmer Divide. Otherwise, the forecast area will remain dry through Tuesday morning. Tuesday through Wednesday...The long term forecast period begins with a closed upper low filling in as it lifts northeast out of the Great Basin and into the northern Rockies. Meanwhile, an upper ridge begins to build over the southwest US. The addition of high pressure over the southeast US will cause south/southeast low level flow from the Texas Gulf Coast into southern Colorado, increasing TPW to around an inch again. As the upper low lifts northeast, a series of shortwave troughs will advance through Colorado. These features will keep a surface boundary draped across the plains each day. The combination of large scale forcing for ascent, surface frontogenesis, and above average moisture will allow for the development of showers and thunderstorms across the eastern mountains and plains each afternoon/evening. Precip chances appear to be greatest over the central and eastern mountains and the plains east of the I-25 corridor, with more isolated coverage across the I-25 corridor. The southwest mountains will stay mainly dry. Given high TPW, heavy rain will be possible with thunderstorms. While a strong thunderstorm with small hail and gusty winds is possible, CAPE and shear will likely be weak enough to limit the development of severe storms. Tuesday will have high temperatures around 90 across the plains and 80 in the high valleys, while temperatures on Wednesday will be cooler, with highs in the low to mid 80s across the plains. Thursday through Friday...As the upper ridge continues to build over the southwest US Thursday into Friday, height rises and associated QG descent will limit precip coverage. However, still above average atmospheric moisture and weak embedded energy should allow for isolated diurnal shower/thunderstorm chances across most of the forecast area. Precip chances appear less on Friday versus Thursday as moisture gets pushed out of the region. High temperatures should be similar on Thursday as on Wednesday, but will rise back into the upper 80s to near 90 on Friday. Saturday through Sunday...Model solutions diverge significantly during this period. The ECMWF advances a progressive shortwave over Colorado by Saturday morning, while the GFS doesn`t bring it in until Saturday night, and the Canadian even later. By this period, GEFS has moderate spread in 500 mb heights. So, while it is appearing probable a quick-moving shortwave brings increased precip chances to the forecast area sometime this weekend, it is still too early to determine more precisely when/where/what. -Line- && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 228 PM MDT Sun Jun 17 2018 Showers and thunderstorms will be possible at KCOS, KPUB and KALS thru this evening. High resolution forecast models suggest a fairly good chance for precip at KCOS and maybe KPUB later this evening, which could continue until around 08Z. Drier weather is expected on Mon, with breezy southerly winds in the afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...28 LONG TERM...LINE AVIATION...28