Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/22/19

Area Forecast Discussion
National Weather Service Billings MT
723 PM MDT Tue May 21 2019 .UPDATE... Rain continues this evening across much of the cwa under persistent isentropic ascent and easterly diffluent flow aloft. Have maxed out pops for our west and south. Only exception is in our northeast (i.e. Miles City to Baker) where drier northeast winds will keep precip lighter and more spotty. Latest RAP shows wet bulb zero heights falling to 4500-5000 ft msl tonight, so a mix with or change to wet snow along the foothills (Red Lodge, Nye, Story, etc) is a good bet. Latest surface analysis shows temps in the low-mid 30s at these locations already. Forecast has this covered well. JKL && .SHORT TERM...valid for Wed and Thu... OVERVIEW: Doubled barreled upper low dominates over the Rockies and upper midwest. One portion of this upper trough will transition to the Great lakes area by Wednesday evening. As the other cut off upper low drops south toward the desert SW. Cool easterly low level flow will turn more northerly tonight into Wednesday. This will favor upslope flow into the Beartooth Foothills and NE facing Big Horns. By Thursday, the upper low to the south tracks over our region. The newer solutions of the GFS and EC cut off moisture for a time on Thursday, which reduces the chance of precipitation. So for this package, we have trended PoP`s down for Thursday and raised afternoon highs a bit. Forecast issues: With the low level flow turning more north/northeasterly tonight into Wednesday, there may be a little more cooling in foothill locations and more efficient precipitation production due to upslope. This includes Nye to Red Lodge, and the Dayton to Story area in the Sheridan Foothills. Most of the snowfall will likely melt on roadways, but areas could become slick late tonight into the morning rush hour. Plus, any snow accumulation could collect on new spring foliage and push down nearby power lines. Confidence in this scenario is low, but given the unusual cool temperatures and forcing aloft, seems prudent to issue winter weather advisories for these areas tonight through 10 am Wednesday morning. IMPACTS: Areal flooding remains a concern this week. However, model QPF has trended downward overall. Major rivers, such as the Yellowstone, have plenty of room to handle additional rainfall. Main concern are low-lying areas, such as ditches, roads and smaller creeks across the CWA. The Little Goose Creek and others in the Sheridan foothills could very well experience minor flooding. BT .LONG TERM...valid for Fri...Sat...Sun...Mon...Tue... The long term continues to look unsettled with multiple disturbances bringing additional chances for precipitation. An upper low lifting north and east through Wyoming and eastern Montana on Friday will bring widespread precipitation, with the greatest totals over far eastern Montana. Overall drier conditions then look to move into the area Friday night through Sunday with some afternoon and evening showers and thunderstorms possible, especially over western areas. Yet another upper low is progged to track out of the Great Basin and off to the north and east early next week, increasing precipitation chances for Monday and Tuesday. Uncertainty exists in regards to the track of the low. These look to be warmer systems, with snow confined to the mountains. High temperatures will climb into the 60s for the weekend and continue into next week. Low temperatures in the 40s look possible most nights/mornings. STP && .AVIATION... Widespread precipitation will bring MVFR/IFR and locally lower flight conditions through tonight and much of Wednesday. Only exception to this is from KMLS to KBHK where drier air will limit flight reductions to MVFR at times. Mountains will remain obscured in snowfall through the period. JKL && .PRELIMINARY POINT TEMP/POPS... Wed Thu Fri Sat Sun Mon Tue ----------------------------------------------------------- BIL 039/051 040/053 040/060 042/065 045/061 046/062 047/065 +8/R 55/W 63/W 12/T 36/T 45/T 43/W LVM 036/048 036/051 035/058 038/062 041/058 041/060 041/063 +8/O 56/W 43/T 25/T 46/T 46/T 44/T HDN 039/050 037/054 039/060 040/066 044/063 045/063 045/067 +7/R 55/W 64/W 12/T 26/T 45/T 54/W MLS 040/053 039/056 040/058 040/066 044/062 044/062 045/065 86/R 34/W 76/W 11/U 23/W 45/T 33/W 4BQ 038/047 036/053 039/057 039/065 044/064 045/061 045/062 +9/O 45/W 74/W 01/U 25/T 46/T 43/W BHK 038/050 036/055 038/055 038/063 041/060 042/058 041/062 78/R 43/W 87/W 11/U 13/W 35/T 33/W SHR 034/045 033/049 034/057 036/063 040/062 042/062 042/062 +9/O 66/W 63/T 12/T 26/T 55/T 54/T && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Flood Watch in effect from midnight MDT tonight through Saturday morning FOR ZONES 28>33-35>39-42-56>58-63-67-68. Winter Weather Advisory in effect until 10 AM MDT Wednesday FOR ZONES 56-66. Winter Storm Warning in effect until 10 AM MDT Thursday FOR ZONES 67-68. WY...Flood Watch in effect from midnight MDT tonight through Saturday morning FOR ZONES 98-99. Winter Weather Advisory in effect until 10 AM MDT Wednesday FOR ZONE 99. Winter Storm Warning in effect until 10 AM MDT Thursday FOR ZONE 98. && $$
Area Forecast Discussion
National Weather Service Des Moines IA
706 PM CDT Tue May 21 2019 .DISCUSSION.../Tonight through Tuesday/ Issued at 352 PM CDT Tue May 21 2019 Overall, looking at an active period of weather over the course of the next week or so with multiple chances for severe weather and rainfall continuing to prime additional river flooding and increasing the flash flooding potential. Upper level low pressure easily seen on the early afternoon GOES- East Clean IR Water Vapor imagery over southwest Kansas with a broad shield of clouds and precipitation to the north, northeast, and east. Locally over Iowa, there is a large area of rain over central spreading into eastern Iowa. This coincides with theta-e advection that is moving in a similar direction along with strong Q-vector convergence. There is a narrow window immediately following the dissipating/ending rain of strong wind gusts with recent gusts at the Carroll AWOS to 53 mph, Atlantic CWOP to 50 mph, Denison AWOS to 50 mph, Estherville ASOS to 51 mph, and Marshalltown ASOS to 50 mph. This strong wind gusts look to continue with the 00z HREF and less so the 12z HREF 4 hour max wind gusts, 00z NCAR Ensemble max wind speeds, and runs of the HRRR continuing to signal strong winds between 50 to 60 knots over north central Iowa. As previous discussion noted, this is likely part synoptic/part convective induced. With this potential seemingly being realized over the southwest forecast area in agreement with model guidance, will allow the Wind Advisory to cover this potential up north and if need be upgrade to High Wind Warning. These wind gusts are on top of the sustained, strong easterly winds that have been prevailing today. Temperatures so far on this damp and windy day are near their minimum maximums in some places, including DSM where the record is 53. So far today through 18z, the high has been 50. Still 8 or so hours for temperatures to bump up before anything is considered official. Another area of showers is expected to move up out of western Missouri into central Iowa, but instability is limited through early this evening with MUCAPE less than 500 J/kg so a few thunderstorms are possible over southern Iowa as this activity moves in. These elevated storms may pose a risk of near severe hail, though threat currently seems quite low. Currently, the nearest lightning via GOES- East GLM data is over central Missouri/roughly I-70 south at mid-afternoon. Several additional rounds of showers and storms are expected tonight, but areal coverage will be much less so than current ongoing precipitation. As the upper low mentioned above lifts north-northeastward into central Nebraska, shortwaves will rotate around and into southwest Iowa. The first wave will be late this afternoon/early this evening roughly arriving 23-00z over southwest Iowa and moving generally northward. Currently expect these to be more scattered showers with very limited instability. The next wave will arrive several hours later around 4 to 5z over southwest Iowa. This will have perhaps the best instability of the `day` with the HRRR indicating between 500 to 1000 J/kg with the RAP closer to 250 J/kg. Deep layer bulk shear is strong between 40 to 50 knots with 0-3 km helicity above 200 m2/s2 with 0-1km helicity similar. Interestingly, the last three runs of the HRRR has an updraft helicity track indicative of a strong, rotating storm over our far western area say from roughly Union up through Carroll County. The HRRR has been consistent with this with slight shifts east and west with runs. If surface based storms are able to form, shear environment is favorable for rotating storms so tornado threat would be non-zero along with hail and wind gust potential. This threat should wane after midnight, but showers will linger over the northern part of the forecast area into early Wednesday morning. As the upper low continues slowly northeastward into the Red River Valley of the North, winds will remain breezy over the state from the southwest, though certainly not as strong as today. A surface boundary will lay out over southeastern Iowa and will serve as a focus for storms Wednesday evening as weak warm air advection passes over the area. While instability will be weak, there will be strong deep layer shear again that could support some large hail or perhaps gusty winds. The western US trough will eject out another shortwave trough in the southwest flow later Thursday. The boundary that was the focus for storms Wednesday evening will lift northward as a warm front and bring back a moisture rich environment with precipitable water values increasing to 1.5 to 2 inches by Thursday night. CAPE values will increase as well into the overnight towards 1000 J/kg with deep layer shear in excess of 40 to 50 knots. Expect storms to form as the low level jet strengthens into southern Iowa with primarily elevated storms posing a risk of hail. Flash flooding concerns will be monitored given the precipitable water values and storm totals between 1 to locally 3 inches. The rest of Friday through Memorial Day will continue to have chances for showers and storms with temperatures generally above normal for late May. With southwest flow remaining aloft allowing for shortwave troughs to move across the region and a surface boundary somewhere in the vicinity of Iowa, hard to find a period at this time frame that would be dry. That is not to say the weekend will be a washout, just hard to nail down a time period at this time horizon. Given the boundary location, strong to perhaps severe storms could be possible as well. In addition, depending on where rains set up, the flash flooding and river flooding concerns may grow as well through the weekend && .AVIATION.../For the 00Z TAFS through 00Z Wednesday evening/ Issued at 706 PM CDT Tue May 21 2019 Widespread showers and IFR ceilings will gradually clear out from south to north late this evening and tonight, with perhaps a period of additional showers and thunderstorms that may affect FOD/DSM briefly overnight. Overall trend in ceiling heights will be up, with VFR conditions expected before sunrise Wednesday. Brisk and gusty east southeast winds this evening will turn through southeast to southwest by Wednesday afternoon, resulting in changing crosswinds on runways. LLWS of 40-50 KT is also anticipated at times overnight. && .DMX WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 10 PM CDT this evening for IAZ004>007- 015>017-023>028-033>039-049-050. && $$ DISCUSSION...Ansorge AVIATION...Lee
Area Forecast Discussion
National Weather Service Quad Cities IA IL
936 PM CDT Tue May 21 2019 .UPDATE... Issued at 931 PM CDT Tue May 21 2019 I have cleared the western 1/2 of the Flash Flood Watch, as the rains have ended. Over all, the current flash flood threat appears low, with fast moving heavy showers not lasting long enough to deposit large amounts of rain. The over all band of rain and heavy showers is putting down generally 0.25 to 0.5 over the eastern half of the area, not that it`s more progressive. Farther west, it did produce 0.5 to 1 inch amounts. I will continue to clear counties as the rain band pushes east tonight. There is a period of strong east winds as the rain ends, which we are handling with an SPS. This is short lived, with sites returning to below 30 mph over locations farther than 30 miles west of the back edge of rain. That wind pulse should continue to move with the back edge of the rain east tonight. && .SYNOPSIS... Issued at 337 PM CDT Tue May 21 2019 Vigorous negative tilt shortwave seen in GOES-16 water vapor and RAP Mesocale Analysis lifting northward across western KS. Attendant deepening surface low (992mb) was north of Dodge City KS, with triple point over E OK and warm front extending eastward across far northern AR. This was providing focus for linear MCS across western AR/MO. Closer to home, Great Lakes ridge has been dominant on our weather for now. Strong easterly flow and cloud cover is resulting in a chilly late May day, with temperatures holding fairly steady around 50 or in the lower 50s. Normal highs are in the lower to mid 70s, so we`re running about 20-25+ degs below. Winds have been quite strong and sustained near 30 mph and gusting over 40 mph in a few locations, in strengthening pressure gradient between the Plains low and Great Lakes high. The lifting shortwave and surging elevated moisture transport will continue to fuel expansive rain shield across the area through this evening. && .SHORT TERM...(This Evening through Wednesday) ISSUED AT 337 PM CDT Tue May 21 2019 Rain will continue to overspread the area through this evening, with increasingly diffluent flow east of vigorous Plains shortwave, and strong moisture transport with PWATS surging over 1.5 to 1.6 inches taking aim on the region. Best potential for embedded convection perhaps taking on an elevated linear presentation exists generally near/south of I-80. Convection will be rooted above 850 mb boundary and shallow with vertical extent through 700 mb or so being deeply saturated above per forecast soundings. This will be atop a brisk stable easterly low level in deep saturation. This will make severe weather unlikely, in the absence of any strong elevated meso. Have kept flash flood watch going along/south of I-80 due to sensitivity to additional heavy rain, and with the anomalous moisture feed aimed into the region. Hopefully though the lack of deep convection and fast motions will limit rainfall amounts and preclude substantial heavy rains. Also, may get help from stratification especially going north through the CWA. In general the heaviest rain swaths are anticipated to be around 0.5 to 1 inch. Temperatures will be steady tonight, with some rise late as the triple point lifts into the region. Wednesday and Wednesday night... Shortwave and attendant surface low will continue to pull away lifting across the eastern Dakotas and MN. Trailing cold front sagging through the region may serve as a focus for convection toward evening, with a weakening mid level cap aided by cooling aloft with ascent from weak low amplitude wave in SW flow aloft. Impressive 0-6km bulk shear 50-60+ kts, and MUCAPE 1000-2000 J/kg supportive of supercell storm structures. Ideal WBZ heights around 8500-9000 ft agl, dry air aloft and steep lapse rates in -10c to -30c layer very favorable for large hail potentially significant. Classic inverted V signature sub-cloud would bring an attendant damaging wind potential mostly prior to nightfall and stabilizing BL. Tornado potential is low with generally deep SSW flow, but would exist with any backing of the low level winds given 0-1km shear progged around 20+ kts. Timing of the severe threat is 5 PM to 10 PM, mainly south/east of a Freeport, IL to Washington, IA line. Gusty SW winds 20-30+ mph on deep mixing to around 850 mb combined with partly to mostly sunny skies, should propel highs well into the 70s to lower 80s Wed PM. A marked change, and considerable improvement over highs from today. .LONG TERM...(Wednesday Night through Tuesday) ISSUED AT 337 PM CDT Tue May 21 2019 Active weather continues throughout with chances for rain and thunderstorms nearly every period, after a brief lull during the day Thursday. Thursday: A passing upper level ridge and weak ridging at the surface should lead to a quite weather day with sunshine at least to start the day and temperatures warming into the 70s and comfortable dewpoints in the 50s. Thursday night into Friday, an upper level wave passing to the northwest will lift a warm front across the area late Thursday night, returning the high moisture airmass to the region. This will also bring back the potential for heavy rainfall and severe storms, initially with the warm front, then in the diurnal instability and convergence with a subtle cold front through Friday night. SPC currently has a marginal risk over the southwest for Thursday, then a 15 percent outlooked for Friday. This will also bring summer-like humidity, with highs in the lower 80s and dewpoints well into the 60s. With the boundary lingering in the region through the weekend into at least early next week under an active southwest to zonal flow aloft, low confidence chances for rain and thunderstorms cannot be ruled out in any period. This does not necessarily depict a rain out for the weekend, as there will likely be some dry stretches between systems. Temperatures will be dependent on the timing of these systems and for now the forecast has highs averaged in the 70s and lows in the 50s and 60s throughout. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening) ISSUED AT 626 PM CDT Tue May 21 2019 A strong storm system will move northeast into Minnesota tonight, helping turn the strong east winds to the south overnight. Initially, a band of moderate to brief heavy rainfall will sweep northeast through all sites between 00z and 06z this evening. While thunder is a low threat, I have only mentioned it at BRL, where a VCTS is mentioned. Beyond a isolated lightning strike, there should be not difference in conditions with the passing band of rain from those that happen to see a strike. Windy, 20 to 35 kts east winds will become southerly towards morning and will slowly decrease through the night, to the 15 to 25 kt window. CIGS will be variably MVFR this evening, as passing showers roll through, and consistently MVFR overnight behind the rain, until the winds become southerly and help bring in VFR conditions for most of Wednesday. There is a low chance for storms Wednesday afternoon, which may be considered for the 06Z TAF issuance. && .HYDROLOGY... Issued at 908 PM CDT Tue May 21 2019 No significant changes have been made on evening updates to area rivers, as the event is taking place as expected with only a few potential differences from earlier forecast. These differences can wait until the morning precipitation analysis to be accounted for with greater certainty. Rain amounts have been a bit lower than forecast thus far, and are expected to coming in with totals mainly between 0.25 and 0.75". For locations near and east of the Mississippi River, amounts are coming in lower than predicted, and have the biggest potential to lower forecasts a bit. This is mainly noted at three sites tonight, first, at the La Moine River at Colmar. It was modeled to reach moderate based on 1.25" rains, but that didn`t happen, and I have lowered the forecast to keep it in Minor tonight, which will be updated again using the gage correction QPE tonight around 11 PM. The others are the Des Moines River at St. Francisville and the Wapsipinicon at DeWitt 4S. They are kept in watch, since amounts are lower than guidance initially used for and they just barely reach flood stage in over 24 hours. Thus, a more accurate warning or cancellation can be issued tomorrow morning. Previous discussion... Issued at 1247 PM CDT Tue May 21 2019 Overnight rainfall occurred mainly south of the I-80 corridor, with the most significant amounts south of the highway 34 corridor. Radar and surface observations indicated amounts from roughly 1 to 1.25 inches fell south of a line from Princeton to Galesburg in IL, and Burlington to Bloomfield in Iowa. The resulting runoff has resulted in rising river levels prompting new flood warnings for the La Moine River at Colmar, the Fox River at Wayland and the Skunk River at Augusta. The Des Moines River at St Francisville saw a quick crest below flood stage, but is now forecast to return to flood stage Thursday, based on forecast rainfall over the next 24 hours. With limited confidence in the rainfall amounts and coverage, a watch has been issued for this location. The latest river forecasts from this morning now incorporate forecast rainfall from the system expected to impact the area tonight. The has resulted in faster rises, and even a few additional crests on many tributary rivers. The Wapsipinicon River at DeWitt is now depicted to reach well into Minor flooding Saturday. With limited confidence in the forecast rainfall, we have issued a FLood Watch for this forecast point. On the Mississippi River, Dubuque LD11 is now forecast to reach Moderate flooding early next week and a flood category upgrade was issued. Further downstream, the new forecasts have upgrades to Major flooding at New Boston and Keokuk. Elsewhere, there was an overall trend of additional rises or faster rises than previous forecasts. With the likelihood of rainfall impacting the area, to some extent, each day in the forecast from Thursday onward, there remains low confidence in the stage forecasts on both tributary rivers and the Mississippi River beyond the first couple days. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Flash Flood Watch until midnight CDT tonight for Scott. IL...Flash Flood Watch until midnight CDT tonight for Bureau- Henderson-Henry IL-McDonough-Mercer-Putnam-Rock Island- Warren. MO...NONE. && $$ UPDATE...Ervin SYNOPSIS...McClure SHORT TERM...McClure LONG TERM...Sheets AVIATION...Ervin HYDROLOGY...Ervin
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
701 PM CDT Tue May 21 2019 .SHORT TERM... (Through Late Wednesday Night) Issued at 437 PM CDT Tue May 21 2019 Line of thunderstorms is expected to move northeast across the CWA late this afternoon and early this evening. Atmosphere has rapidly destabilized ahead of it as 60s and lower 70 dewpoints have surged north into the southern CWA allowing for MLCAPES to jump into the 1000-1500+ J/kg range. This is further evidenced by the appearance of a well developed cumulus field that is moving northward into the CWA. Latest RAP low level convergence fields supports CAMS simulated reflectivity which depicts the current line progressing eastward across the CWA through the evening. Deep layer and low layer shear supports the line producing damaging winds with embedded tornadoes and perhaps some hail given the steep lapse rates. In addition any discrete storms that do develop ahead of the line will also be capable of producing all hazards. Will continue the flash flood watch until midnight. While the line will be progressive, it will have very heavy rainfall rates. Therefore cannot rule out a flash flood threat given the already wet ground over the area. This line will move east of the CWA after midnight with dry conditions expect by 12Z. Wednesday looks like about one of the only dry days as the there will be no upper systems moving across the area. By Wednesday night however, both the NAM/GFS are showing another weak shortwave moving over the area at the some time that a front will be aligned over Missouri and Illinois. Will go with a chance of showers and thunderstorms as there may be some chance for a few strong storms. Britt .LONG TERM... (Thursday through Next Tuesday) Issued at 437 PM CDT Tue May 21 2019 The extended part of the forecast will be highlighted by warm temperatures and a chance of thunderstorms through the Memorial Day weekend. The GEFS and deterministic models are in reasonable agreement into early next week that east-west front set up underneath quasi-zonal upper flow. This will be between a large upper high over the southeastern CONUS and trough over the southwest. Coverage of thunderstorms over our area will be determined by the ultimate location of the front and how much upper ridging will be over the CWA. For now will keep with above normal temperatures given forecast 850mb temperatures between 15-20C and a persistent chance of thunderstorms. Britt && .AVIATION... (For the 00z TAFs through 00z Wednesday Evening) Issued at 641 PM CDT Tue May 21 2019 A line of thunderstorms will continue to affect the St. Louis area terminals through 01Z before moving into Illinois. There will be a threat for gusts up to 50KTS, hail, and isolated tornadoes at KCPS. There will also be MVFR/IFR ceilings and visibilities with it. MVFR visibilities and ceilings will also occur at KUIN and KCOU before moving out later this evening. Then dry and VFR conditions are expected at all of the terminals by 06Z. SPECIFICS FOR KSTL: Thunderstorms will move east of the terminal by 01Z. Dry and VFR conditions expected by 06Z. Southerly winds will gust to around 20KTS at times trough the end of the period. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Flash Flood Watch until midnight CDT tonight for Audrain MO- Boone MO-Callaway MO-Cole MO-Crawford MO-Franklin MO- Gasconade MO-Iron MO-Jefferson MO-Knox MO-Lewis MO-Lincoln MO-Madison MO-Marion MO-Moniteau MO-Monroe MO-Montgomery MO- Osage MO-Pike MO-Ralls MO-Reynolds MO-Saint Charles MO- Saint Francois MO-Saint Louis City MO-Saint Louis MO-Sainte Genevieve MO-Shelby MO-Warren MO-Washington MO. IL...Flash Flood Watch until midnight CDT tonight for Adams IL-Bond IL-Brown IL-Calhoun IL-Clinton IL-Fayette IL-Greene IL- Jersey IL-Macoupin IL-Madison IL-Marion IL-Monroe IL- Montgomery IL-Pike IL-Randolph IL-Saint Clair IL-Washington IL. && $$ WFO LSX