Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/27/19

Area Forecast Discussion
National Weather Service Cheyenne WY
527 PM MDT Sun May 26 2019 .SHORT TERM...(This evening through Tuesday night) Issued at 230 PM MDT Sun May 26 2019 Forecast concerns in the short term deal with severe storms...heavy rain leading to possible flooding/flash flooding and heavy mountain snow. Currently...surface low analyzed pretty much over Cheyenne this afternoon. Stratus layer has hung tough over the Panhandle and hear at Cheyenne so far...limiting convection. Outside of the convection up in Platte and Converse Counties though... storms are firing and moving northeast. Latest SPC Meso Analysis up that way showing an uncapped environment with surface based CAPE around 3000 J/Kg. Southern Panhandle still capped with 50 to 75 J/Kg inhibition. Latest HRRR guidance showing storms developing fairly widespread after 21Z with cap breaking over the southern Panhandle after that time. Line of thunderstorms form just west of Cheyenne and moves east with increasing intensity on storms. Storms will be moving into very unstable environment with meso analysis page showing 3000 J/Kg over the southern Panhandle after 00Z. Severe thunderstorm threat begins to ease after 02Z. Went with a Flash Flood Watch for the central Panhandle...Goshen...eastern Laramie County and eastern Platte County as a rather large area of moderate to heavy precip remains in place over the area overnight. Storm motions decrease significantly we will be dealing with slow motions with storms producing heavy rainfall over these areas. Dangerous night time flooding is possible. Guidance continues to show widespread heavy rainfall over the Laramie Range and points east Monday into Tuesday with 6 hour QPF forecasts of .75 inches through at least Tuesday afternoon. SO kept Flood Watch for our northern zones going and even extended them into Wednesday morning before precip ends. One final issue...getting some pretty high snow amounts in the Snowy and Sierra Madre Ranges. 12-24 inches of snow possible for these ranges before snow ends Wednesday morning. Decided to issue a Winter Storm Watch for these zones as a result. .LONG TERM...(Wednesday through Sunday) Issued at 230 PM MDT Sun May 26 2019 Wednesday...A bit warmer as the airmass moderates and we see some more sunshine. With the upper trough over South Dakota and wrap around moisture, we will still see a slight chance of showers and thunderstorms over our northern counties. Thursday...Drier and warmer conditions expected as weak shortwave ridging builds overhead, though there will still be enough residual low and mid level moisture for some showers and thunderstorms over the Snowy and Sierra Madre Ranges in the afternoon. Friday...Ridging aloft flattens somewhat as the next weak shortwave trough aloft approaches from the Great Basin states. With some increase in low and mid level moisture, we anticipate an increase in afternoon shower and thunderstorm coverage over the Snowy, Sierra Madre and Southern Laramie Ranges. Saturday...Despite some ridging aloft, there will still be enough residual low and mid level moisture for isolated to scattered afternoon and evening showers and thunderstorms. Slightly cooler with more cloud cover and better coverage of showers and thunderstorms. Sunday...Best low and mid level moisture is progged to be over our eastern counties, where scattered late day showers and thunderstorms will develop along and east of the low level surface trough axis along the Interstate 25 corridor. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 521 PM MDT Sun May 26 2019 Wyoming TAFS...VFR at Rawlins with thunderstorms in the vicinity until 02Z. Wind gusts to 25 knots until 02Z. VFR at Laramie with occasional thunderstorms and MVFR until 02Z with wind gusts to 35 knots. VFR at Cheyenne, with occasional MVFR until 02Z in thunderstorms, with wind gusts to 45 knots. Becoming IFR from 08Z to 15Z, then VFR. Nebraska TAFS...Occasional MVFR in thunderstorms at Chadron with gusts to 35 knots until 03Z, then VFR until 08Z, then IFR until 15Z, then VFR. IFR at Alliance until 03Z, with occasional thunderstorms producing MVFR and wind gusts to 35 knots, then VFR from 03Z to 08Z, then IFR until 15Z, then VFR. Occasional MVFR at Scottsbluff until 03Z with occasional thunderstorms producing MVFR and wind gusts to 35 knots, then VFR until 08Z, then IFR until 15Z, then VFR. Occasional MVFR at Sidney until 03Z, with thunderstorms producing wind gusts to 35 knots, then VFR from 04Z to 07Z, then IFR until 15Z, then VFR. && .FIRE WEATHER... Issued at 425 AM MDT Sun May 26 2019 Recent precipitation across southeast Wyoming and the western Nebraska Panhandle will continue the low fire weather concerns. Continued unsettled weather will bring near daily chances for showers and thunderstorms as the cool and wet pattern progresses on for the near-future. The driest day in the forecast looks to be today with afternoon humidities reaching down into the upper teens to low 20s west of the Laramie Range. Gusts will reach up to 20 mph; stronger near and around thunderstorms && .HYDROLOGY... Issued at 425 AM MDT Sun May 26 2019 With the recent wet, heavy snowfall across the area, reports have area streams and creeks at bankfull with portions of the White River flooding nearby pastureland near Hwy 385. The White River sensor at the NE/SD border has been slowly declining, however, the continued wet pattern and snowmelt will likely not ease the flood risk or water levels for the next several days. A Flood Advisory remains in effect to accommodate these concerns. Biggest concern going forward will be the possibility of rain on snow from the mountain ranges to the Pine Ridge in NE. Depending on rates and intensity, further flooding concerns remain for rapid rises in area rivers and streams besides the White River, and other low- lying areas. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Flood Watch through late Tuesday night for WYZ102. Flash Flood Watch through Monday afternoon for WYZ107-108-119. Flood Watch from Monday afternoon through Tuesday afternoon for WYZ101. Winter Storm Watch from Monday evening through late Tuesday night for WYZ112-114. NE...Flood Watch through late Tuesday night for NEZ002-003-095-096. Flash Flood Watch through Monday afternoon for NEZ019>021-054- 055. && $$ SHORT TERM...GCC LONG TERM...RUBIN AVIATION...RUBIN FIRE WEATHER...GCC HYDROLOGY...AB
National Weather Service Sioux Falls SD
1049 PM CDT Sun May 26 2019 .SHORT TERM...(This Evening through Monday) Issued at 307 PM CDT Sun May 26 2019 The concern over the next few days will be the potential for several rounds of showers and thunderstorms with the threat for occasional severe weather and heavy rain. First wave of energy begins to approach the area by this evening along with favorable broad lift via the right entrance region of an upper level jet streak. This will allow showers and thunderstorms to blossom over much of SD/NEB and push eastward with time. Various forecast soundings, along with HREF guidance, suggests up to/around 1000 J/kg of MUCAPE by this evening, slowly fading as the night wares on. Combine this with 30-45 kts of 0-6 km shear (early on) and could see a storm or two approach the strong to severe category. With this said, the better instability, and thus severe threat, is bottled up to the south and leaves some question about convective interference this far north. The marginal risk along and south of I-90 from SPC for tonight looks good at this point. Of equal or greater concern for tonight is the threat for locally heavy rain. Models differ in how quickly to initiate convection to our south and move it eastward, which will likely impact where the better focus for convection and rainfall is across our area. This was very apparent in earlier runs between the GFS/GEFS/HRRR/WRFs and the NAM with the latest HRRR migrating more to the NAM camp. Long story short, with PWATS running near or above the 90th percentile of climatology and the potential for repetitive thunderstorms, the heavy rain threat will certainly be something to keep an eye on the trends into the evening/overnight hours. Debated the need for a Flash Flood Watch but would prefer to allow for higher confidence in a more specific spatial focus. WPC`s slight risk of excessive rainfall looks to be well justified. Showers and thunderstorms continue into at least the morning hours Monday before the better forcing pulls east and broad subsidence briefly sets in for the afternoon. Still will maintain some slight and chance level POPs thru the afternoon hours. Overnight and morning guidance continues to hone in on the surface boundary remaining near or south of our far southern counties. This would also likely keep the better severe threat Monday afternoon and evening south as well although enough elevated instability is present to leave some risk in place, especially along and south of I- 90. The bigger question revolves around if and how many storms form with the various hi-res guidance not overly convincing. .LONG TERM...(Monday Night through Sunday) Issued at 307 PM CDT Sun May 26 2019 Probably the next better chance of additional locally heavy rainfall and potential severe weather arrives Tuesday afternoon and overnight. Surface low and attendant front are a bit further south than in previous model runs, but much will likely depend on convective evolution over the next 48 hours. If these features can sneak a bit further north, ample instability and shear exists in the warm sector for a severe threat with elevated instability to the north. For now, SPC has highlighted a few of our NW IA counties in an enhanced risk but expect this to evolve overtime depending on model trends. Upper level low swings overhead for Wednesday and will allow for lingering precipitation, perhaps longer if the slower GFS verifies. For late week into the weekend, the region eventually finds its way under a somewhat chaotic northwesterly flow aloft with occasional disturbances and precipitation chances, although less expansive than the early week systems. Temperatures thru the extended range from the 60s to 70s with the later half of the extended having the better chances for the warmer temps. As with much of the forecast, much will depend on boundary locations and convective contamination. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1048 PM CDT Sun May 26 2019 Thunderstorms will continue to become more widespread through the overnight hours, with periods of heavy rain and cloud to ground lightning being the primary threats. Brief erratic gusts winds are also possible under the stronger storms. Heavy rain could lead to reduced surface visibilities during the early morning hours, and ceilings will lower into MVFR & IFR categories Monday morning. Rain decreases in coverage after sunrise, with only isolated showers remaining after noon Monday. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ SHORT TERM...Kalin LONG TERM...Kalin AVIATION...VandenBoogart
Area Forecast Discussion
National Weather Service Hastings NE
638 PM CDT Sun May 26 2019 .SHORT TERM...(This evening through Monday) Issued at 400 PM CDT Sun May 26 2019 Tonight: The concern for today continues to be the chance for strong to severe thunderstorms this evening and overnight across the area. Thunderstorms have already begun in eastern Colorado and western Kansas and this activity is expected to expand northward and move through the area this evening and overnight...possibly in a couple of waves. The latest HRRR runs 18/19z and the 18z NAMnest all hint at an earlier start time than we have been thinking for some time. Over the past day and throughout this morning, the main show looked to begin near to just after 00z. The latest high-res runs show development in the 22-23z time frame in western sections of the area from Dawson County south. Time will tell, but this certainly is a possibility is a change from earlier thinking. Believe that hail and wind is the primary threat from the first activity, but feel that storms will develop into a line downstream of western KS which will cause wind to be the primary threat later this evening and overnight. A secondary line of storms may develop and move across the area during the overnight hours behind the first wave. Uncertainty in this due to model disagreement, but is possible. A tornado cannot be ruled out, but should be confined to areas south of the NE/KS border. The main threat will be strong winds and hail. In addition to those concerns heavy rainfall and with the main line of storms and any additional overnight storms could cause flooding across the area. The most likely area to see flooding is the saturated south and southeastern sections of the area. Kept the Flash Flood Watch and added Webster, Nuckolls, Thayer and Fillmore counties to it. Those areas showed the most saturated antecedent conditions for the month of May and especially in the last 7 days. The Watch goes through 12z. Monday: Preciptiation should exit the area by sunrise as the upper disturbance driving tonights activity moves off to the northeast. The main trough and upper disturbance will continue to round the base of the trough and move towards the central Plains for Monday. As this disturbance approaches lee cyclogenesis will increase and the surface low will develop in eastern Colorado. There are a couple of questions with how this will evolve though...especially the location/placement of the dryline and warm front. Will the warm front be draped across central NE or near the SD border. All questions to be answered and they will impact how Monday will pan out. Am slightly concerned that something could develop off the dryline west of Hwy 183 and track northeast across the area. This could be more discrete activity, but it could also not occur at all. Monday is expected to be dry through the early afternoon and then it is conditional for the remainder of the day/night. Stay tuned. .LONG TERM...(Tuesday through Sunday) Issued at 400 PM CDT Sun May 26 2019 Tuesday: The upper low/trough has continued to slow its exit from the area. The main disturbance is slower to eject out to the north...thus slowing the departure of surface low and associated fronts. The dry line looks to set up somewhere near Hwy 281 and this could be the right scenario for thunderstorms with discrete propagation, thus promoting supercells and potentially tornadoes. This is a day to watch. Think this will be an earlier show as the initiation will begin in the forecast area before exiting to eastern Nebraska and eastern Kansas. Wednesday - Sunday: A period of drier and cooler weather is expected Wednesday behind the cold front Tuesday night. Highs will be in the 60s before rising back in to the 70s and 80s for the weekend. Brief northwesterly flow will become zonal-ish as numerous ripples/weak disturbances move across the heart of the country. Thunderstorm potential returns Friday through Sunday. There are discrepancies with the details of these ripples, so difficult to discern much more than that. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday) Issued at 638 PM CDT Sun May 26 2019 The first 12 hours of this forecast is fairly messy. A line of convection is ongoing and is expected to impact both terminals within the next few hours. Ceilings are expected to become MVFR with the precipitation and during the thunderstorm winds could gust to near 40kts. There could be a couple rounds of thunderstorms and thus have prevailing thunderstorms or VCTS through most of the next 12 hours. By 12z, precipitation should end and be off to the east/northeast. Ceilings may drop back down to MVFR, but have kept VFR for now. Winds are expected to become more southerly during the day tomorrow. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Flash Flood Watch through Monday morning for NEZ077-085>087. KS...Flash Flood Watch through Monday morning for KSZ005>007-017>019. && $$ SHORT TERM...Billings Wright LONG TERM...Billings Wright AVIATION...Billings Wright
Area Forecast Discussion
National Weather Service Marquette MI
629 PM EDT Sun May 26 2019 .SHORT TERM...(This evening through Monday) Issued at 406 PM EDT SUN MAY 26 2019 Water vapor imagery and RAP analysis show a trof over the western CONUS, featuring a deep mid-level low over central CA. Shortwave ejecting from this trof across southern AZ will be a feature of interest for the weather here on Memorial Day. Downstream from the trof, a ridge is over the Gulf Coast States. To the n, a trof is over central into se Canada. Within this trof, a shortwave swinging across northern Ontario is pushing a cold front s across Lake Superior and into Upper MI this aftn. Despite the convergence from front and active lake breezes this aftn, very little instability and slight warm nose/weak capping inversion has only allowed for relatively flat cu development, and this cu has been spreading out with time. In the confluence zone btwn the Gulf Coast ridge and the Canadian trof, axis of 100+kt upper jet runs from far southern Manitoba across northern Ontario, just n of Lake Superior. Right entrance upper divergence associated with this jet and mid-level fgen down at the mid levels is supporting sct -shra across far southern Manitoba e along the MN/Ontario border region. Tonight, aforementioned upper jet will increase to 130kt. Right entrance of this upper jet along with low-mid level fgen will continue to support some -shra off to the nw. Approach of a northern stream shortwave, currently over se Saskatchewan, should give a boost to -shra development late tonight/Mon morning. Most of the models capture this idea and streak a band of -shra across nw Lake Superior and the Keweenaw late tonight and Mon morning. Seems reasonable and will include chc pops for now. Whether these -shra survive ese into eastern Alger/Luce Counties Mon morning is less certain as forcing weakens with time. During Memorial Day, attention then turns to the shortwave over southern AZ. As this waves lifts to the Upper Mississippi Valley/western Great Lakes by evening, it will spread a shield of shra toward Upper MI. Given the upper confluence zone over the northern Great Lakes, there is uncertainty in how far n the pcpn will spread. At a minimum, agreement is good for s central Upper MI to see shra arrive in the aftn. Likely to categorical pops will be utilized there. Will then shade pops down to schc/low chc n. Keweenaw may not see any additional pcpn after the sct morning shra. As for temps, 40s will be the rule tonight though a few spots n central may dip just blo 40F. Clouds and easterly winds will make for a notably cooler day on Memorial Day. Expect 40s near Lake Superior in areas exposed to an easterly wind across the lake and only 50s elsewhere. .LONG TERM...(Monday night through Sunday) Issued at 300 PM EDT SUN MAY 26 2019 The long-wave pattern over the CONUS beginning Monday night continues to depict persistent ridging over the southeast and Gulf of Mexico, with a closed low slowly working it`s way east across the west. Previously, this feature was expected to weaken and transition to an open wave, crossing the western Great Lakes Wednesday into Thursday. The trend now is for a slower transition and it is now expected to reach Upper Michigan on Thursday or perhaps Thursday evening. With preceding shortwave activity now likely to pass mainly to our south, medium/long-range forecast models have continued to trend drier through the middle of next week for our area. After the trough passes, models depict split flow over the NW CONUS and a NW flow regime for us, with cooler temperatures and chances for showers and thunderstorms with an embedded shortwave currently forecast to push through on Saturday. Rainfall is still expected to be ongoing Monday evening, mainly across the southern tier of counties. This shortwave will be weakening as it moves east and rain will come to and end before sunrise Tuesday. Total precipitation accumulation will range from <0.1" near the Lake Superior shores to perhaps as much as 0.7" near Menominee, with most locations receiving between 0.1-0.4". Afterwards, weak surface ridging will take over and conditions will remain dry Tuesday and Tuesday night, although clouds may be slow to clear if at all, especially south. A weakening shortwave early Wednesday morning will be pushing northeastward through the southern half of Wisconsin, and while most data suggest that this will remain to our south, the 12Z ECMWF does bring some showers into the far southern portions of the UP and the forecast does include this possibility. Besides that, generally dry, seasonal conditions can be expected into Thursday morning. As the closed western CONUS low begins to open and lift across the western lakes, general agreement is that the main area of forcing will be rapidly weakening and likely passing to our south and east Thursday. The next chance for wet weather will come as early as late friday night but likely into Saturday as longwave troughing intensifies south of a closed Hudson Bay low and a cold front approaches from the north. There may be chances for some embedded thunder with this but available buoyancy is questionable at this time. Cooler temperatures will filter in for next weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 629 PM EDT SUN MAY 26 2019 Drier air will linger in the lower levels thru most of this fcst period, allowing VFR conditions to prevail at KIWD/KCMX/KSAW. By Mon afternoon, rain will start to move in and allow MVFR conditions to settle in. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 406 PM EDT SUN MAY 26 2019 Cold front dropping s across Lake Superior will bring a surge of ne winds gusting to 20-30kt for a few hrs this evening over western Lake Superior. Over the e half of the lake, winds will remain under 20kt tonight. As a disturbance lifts ne toward the Great Lakes on Mon, expect ne winds in the 15-25kt range over western Lake Superior. Some gusts to 30kt are possible. Winds will be under 20kt across the rest of the lake. It then appears that winds should be generally under 20kt thru the mid and late week period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...KCW AVIATION...07 MARINE...Rolfson
Area Forecast Discussion
National Weather Service Tulsa OK
929 PM CDT Sun May 26 2019 .DISCUSSION... Line of storms this evening currently across the TX/OK panhandles will continue to move east, however latest CAM solutions are a mixed bag with keeping the line together vs dissipating while moving northeast. HRRR is most aggressive with weakening convection overnight. Should storms hold together, the timing would likely be after 09z before activity enters northeast Oklahoma. Will keep high chance pops going for late tonight across parts of far NE OK. Rest of forecast looks good and will be left as is. Updated ZFP/PFM/AFM out shortly. && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...23