Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/09/20

Area Forecast Discussion
National Weather Service Cheyenne WY
753 PM MDT Mon Jun 8 2020 .UPDATE... Issued at 751 PM MDT Mon Jun 8 2020 Decided to go with a Winter Weather Advisory for the Laramie Valley and eastern Snowy Range Foothills. Looking at WYDOT webcams...I-80 is getting snow covered. Radar continues to show areas of moderate precipitation out snow is likely to continue through the evening hours at least. Updates have been sent. UPDATE Issued at 739 PM MDT Mon Jun 8 2020 Temperatures have tanked out west over the Summit and in the Laramie Valley from Laramie to Arlington. Redid temperatures and snow levels to bring snow into the forecast for these locations. May need to issue short fused snow advisory for the Laramie Valley if this keeps up. Updates have been sent. UPDATE Issued at 508 PM MDT Mon Jun 8 2020 Looking over latest short term guidance...getting 47kt wind gusts off LAMP MOS. Latest HRRR 850mb winds over the southern Panhandle 60kts this evening into Tuesday morning. Can`t ignore this and therefore...went with a High Wind Warning for the southern 4 counties in the Panhandle. Updates sent. && .SHORT TERM...(This evening through Tuesday night) Issued at 256 PM MDT Mon Jun 8 2020 Interesting forecast overnight into Tuesday as a potent upper level system moves across the region, bringing rain and a few storms, winds, and even some accumulating snows. Currently seeing a persistent band of showers and a few embedded tstms over se Wy mainly across eastern Albany county. Expect this area to expand through this evening as the upper level system moves into Colorado and cuts off an upper low near the 4 corners area. Meanwhile a strong cold front will sweep across the CWA this evening with pretty gusty winds behind it for a time. Snow levels will drop to about 7500 feet overnight and still looks like several inches of snow may accumulate by morning over the Snowys as well as the I-80 summit area, so current advys look in good shape. Snow amounts nudged down a bit but not significantly changed. The low pressure system will move into the central plains Tuesday with the pcpn ending over most of the CWA by Tuesday afternoon. Will still need to watch for the potential for strong winds especially over the southern Panhandle though it still appears the winds will be limited by rain and cooler temps. Still some gusts over 50 mph possible. Winds will ease Tuesday evening setting up for a clear but chilly night with patchy frost possible in some higher valleys. .LONG TERM...(Wednesday through Monday) Issued at 256 PM MDT Mon Jun 8 2020 Dry and warmer conditions return for Weds through Friday as upper ridging builds over the Rocky mtn chain and slips east over the CWA. The warm conditions will persist through the weekend with chances for convection returning as the upper flow turns swly ahead of the next upper trough that will move over the Pacific NW. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 511 PM MDT Mon Jun 8 2020 Band of moderate rain remains over the Summit and Laramie Valley late this afternoon. Expecting IFR conditions for KLAR with a favorable upslope wind flow for them. Temperatures tanking tonight with snow developing over the Summit and possibly even at KLAR. Very strong winds expected after 06Z for the southern Panhandle that persist into early afternoon. && .FIRE WEATHER... Issued at 256 PM MDT Mon Jun 8 2020 A low pressure system and associated cold front will move across the region tonight into Tuesday bringing widespread wetting rain with even some snow over the mountains mostly tonight into Tuesday morning. It will be pretty windy tonight and Tuesday over the plains. The system will move away during the day Tuesday with warmer and mainly dry weather making a return for the rest of the week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory until noon MDT Tuesday for WYZ110- 114>116. NE...High Wind Warning from midnight tonight to 3 PM MDT Tuesday for NEZ020-021-054-055. && $$ UPDATE...GCC SHORT TERM...RE LONG TERM...RE AVIATION...GCC FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Dodge City KS
545 PM CDT Mon Jun 8 2020 ...Updated Aviation... .UPDATE... Issued at 503 PM CDT Mon Jun 8 2020 ...Damaging High Winds Possible Tuesday Afternoon... Updated near term grids through Tuesday to increase pops/QPF for rain showers with the upcoming system. All models have now come on board with what the ECMWF first suggested, with widespread wrap around rain reaching about the northern half of SW Kansas. Increased pops to the likely category for these zones, and increased the storm total QPF to a 0.25-0.75 inch range, highest with northern extent. 18z NAM is quite wet, suggesting over an inch for many locations. Won`t go that far yet in a drought. Southern zones adjacent to Oklahoma will receive the least rain, and some areas in the SE zones may get zero. High wind warning will be reissued and updated shortly, increasing mentioned gusts to 70 mph. An impactful high wind event is apparent Tuesday afternoon, with the strongest NW winds favoring, as usual, the preferred US 83 corridor. Here, the MAV guidance is extreme, showing 60 mph SUSTAINED winds at Garden City Tuesday afternoon. This forecaster has never seen that before, therefore did not put it into the forecast. Increased the wind/wind gust grids with a muted (-5mph) version of MAV, which still gives gusts near 70 mph along US 83. 12z ECMWF also forecasts mslp gradients near 20 mb across the SW KS CWA at 1 pm Tuesday, also something this forecaster has not seen. The 850 mb flow near 60 kts will certainly support these gusts. Uncertainty how much cloud cover and rain showers will work to deter/encourage vertical transfer of momentum. Evaporating rain showers would aggravate the winds; hopefully, cloud cover will be thick enough to save us from widespread wind damage. && .SHORT TERM...(This evening through Tuesday) Issued at 156 PM CDT Mon Jun 8 2020 Warm air in the mid levels will make convection along a surface boundary extending from near Dighton to Sublette difficult this afternoon...if at all. As of 18z Tuesday Satellite is indicating the only cut field in north central Kansas was north of the Ellis and Trego county line. WIll continue to monitor this area for possible further development but should something develop it will be isolated with the main hazard being gusty winds. Models today differ some on the timing of a strong surface cold front crossing southwest Kansas late tonight/early Tuesday morning but what all the models are in very good agreement with are the 55 to 65 knot northwest winds around the 850mb level developing behind this cold front as an upper low deepens and moves into western Kansas during the early morning hours. HRRR produces wind gusts of near 50 knots by 12z Tuesday west and north of Garden City which currently appears to be on track given the boundary layer and 850mb forecast winds in this location. These strong winds will spread east across western Kansas early Tuesday and then across central Kansas during the afternoon a deepening surface low, located near the Hays area at 12z Tuesday, moves into north central Kansas and the upper low crosses western Kansas. Given the good agreement between all the models and after good collaboration with our surrounding offices will upgrade the current high wind watch to a high wind warning for Tuesday and then issue a high wind watch for locations east of a Wakeeney to Dodge City line. These strong winds east of Dodge appear to linger into the evening period. Scattered rain showers and even some thunderstorms will be possible during the day on Tuesday based on the instability and moisture that will be present under the upper low that will be crossing western Kansas during the day. Severe weather at this time is not anticipated in the Hays area Tuesday afternoon but severe thunderstorms may not be too far away given the forecast shear and instability Tuesday afternoon that will be located in north central Kansas. Later shifts will have to monitor the moisture wrapping around the surface low and exactly how far east/northeast this surface system tracks during the afternoon. Strong winds on Tuesday will likely create areas of blowing dust across western Kansas despite the chance for precipitation on Tuesday. This blowing dust will likely reduce visibilities at times. Unseasonably cool temperatures can be expected across western and central Kansas during the afternoon on Tuesday. Most areas will have the highs for the day occur during the morning with temperatures then remaining nearly steady or falling in the afternoon. Afternoon temperatures will likely be in the 50s and 60s. .LONG TERM...(Tuesday night through Monday) Issued at 156 PM CDT Mon Jun 8 2020 On Tuesday night the precipitation over western Kansas will taper off as the moisture and lift northwest of the upper low moves into central Kansas. The Strong winds will decrease Tuesday night as an area of high pressure begins to build into the western Kansas and eastern Colorado. This clearing trend across far western Kansas along with decreasing winds will air in allowing temperatures to fall back into the 40 to 45 degree range. Elsewhere the lows Tuesday night will range from 45 to 55 degrees. After this cloudy, very windy, and cool Tuesday some warmer temperatures will be returning to western Kansas mid week. Highs in the mid 90s to upper 90s will be possible from Friday through the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 545 PM CDT Mon Jun 8 2020 Aviation weather impacts this period will include rain (especially northern terminals), widespread stratus (down to MVFR) and very intense NW winds Tuesday. Elevated/gusty S/SE winds will continue most of tonight, before a strong cold front arrives at the airports around 12z Tue. Consensus of short term models shows widespread post-frontal MVFR stratus cigs daylight Tuesday, with the lowest cigs at HYS and the highest at LBL. Widespread rain showers are also expected daylight Tuesday, most numerous with northern extent (GCK-HYS). A high wind event is expected Tuesday midday/afternoon, with intense NW winds at all airports. The strongest wind gusts are expected along US 83 (LBL-GCK) where gusts are expected to reach near 60 kts. This TAF forecast will carry gusts of 52-54 kts at DDC, and 40-45 kts at HYS. Particularly at GCK/LBL, these intense winds will impact aviation operations strongly Tuesday with wind damage possible. && .PRELIMINARY POINT TEMPS/POPS... DDC 60 63 50 83 / 0 60 60 0 GCK 55 58 48 82 / 0 70 50 0 EHA 52 65 48 85 / 0 20 10 0 LBL 55 65 48 85 / 0 20 10 0 HYS 64 70 50 79 / 0 70 60 0 P28 69 79 55 86 / 0 10 10 0 && .DDC WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 8 AM CDT /7 AM MDT/ to 9 PM CDT /8 PM MDT/ Tuesday for KSZ030-043>045-061>064-074>078-084>088. High Wind Watch from Tuesday morning through Tuesday evening for KSZ031-046-065-066-079>081-089-090. && $$ UPDATE...Turner SHORT TERM...Burgert LONG TERM...Burgert AVIATION...Turner
Area Forecast Discussion...CORRECTED
National Weather Service Duluth MN
1016 PM CDT Mon Jun 8 2020 .MESOSCALE DISCUSSION... Issued at 1009 PM CDT Mon Jun 8 2020 Showers and thunderstorms continued to redevelop along a line from north of Atikokan, ON to Littlefork, MN to Kelliher, to near Park Rapids and Wadena, but sustained development continues to be slow along this axis. The showers and storms appear elevated above the surface layer. SPC RAP mesoanalysis indicates 1500 to 2500 J/kg of MLCAPE, however the storms seem unable to tap into this energy at this time. That area continues to be the main focus for additional storm development during the next 2 to 4 hours as convergence increases due as a south-southeasterly 850 mb low- level jet strengthens. Storms in northwest Ontario southwest into northwest Minnesota seem to be surface-based in the warm sector south of a warm front. A stout cap around 650 mb was observed on the 09.00Z INL sounding, which will continue to limit the extent of the convective potental until southwest winds advect cooler air from the Red River Valley. Think the cap should erode enough to support more widespread convection over our western and northwestern zones between 12 and 2 AM. && .SHORT TERM...(This evening through Tuesday night) Issued at 327 PM CDT Mon Jun 8 2020 A very slow moving cold front is situated over the Dakota/MN border this afternoon with a large reservoir of CAPE (3000+ J/kg) sitting ahead (east) of it. The only thing holding back strong convection is a large cap sitting at the 700 mb level. The cap thins meridionally to the north about where low level convergence maximizes which puts the International Falls/Koochiching County area in the bullseye for strong storms this evening and perhaps overnight as upper level forcing approaches from the west. With PWAT`s near 1.7" - these storms could also produce extremely heavy rainfall. This rainfall will add to that received within the last 48 hours, so there may be a bit of a flash flooding concern, but overall the geology/ecology is pretty receptive to heavy rainfall events. Other threats will be large hail, strong winds, and even an isolated tornado is possible given the bulk shear values around 50 knots coupled with the generous instability values present. A shortwave lifts north overnight and will likely help to maintain convection through the overnight hours despite CAPE values trending downwards. All of this activity doesn`t look to move too far east into the MN Arrowhead and rather hangs out near the slow moving front and only intensifies as that shortwave quickly translates northward into Canada - mainly because an upper level ridge is slow to exit to the east which should buffer the remainder of the forecast area. Occasionally, an MCS may overcome this and migrate off the front causing havoc to the forecast, so subsequent shifts will have to keep an eye out for that as the derecho composite does leak some relatively higher values into the MN Arrowhead. For the remainder of Tuesday, there will be a break in the action before the remnants of Tropical Depression Cristobal begin to arrive by Tuesday evening/night. .LONG TERM...(Wednesday through Monday) Issued at 325 PM CDT Mon Jun 8 2020 The remnants of Tropical Depression Cristobal will be the main driver for the extended period with most of the impacts being felt before Thursday morning. The surface low associated with this system will spin northward Wednesday with the centroid crossing through Central Wisconsin and drifting northeastward into the UP of Michigan Wednesday morning. As the low crosses, a rich 2+" PWAT air mass will drift overhead. This will set the stage for the potential for very heavy rainfall rates Tuesday night into Thursday morning. Would not be surprised to see several inches of rainfall in a 6-12 hour period with the initial surge of moisture which is expected to mainly effect northwest Wisconsin, but add into the equation a lot for uncertainty for the overall breadth of the system - heavy rainfall may reach as far west as central Minnesota. This is especially true since a weak frontal boundary will continue to linger in the central MN vicinity from earlier storms on Monday and Tuesday which may help to improve forcing to the west of the low track. Upstairs, the main meridionally moving vort max associated with Cristobal arrives Tuesday night, but is followed closely by a zonally traveling upper level trough that some models indicate will bring a second surge of moisture following Critobal`s departure giving a 1-2 punch of heavy rainfall. Due to the warm- core nature of the system, I don`t foresee too much thunder in the forecast for the majority of Cristobal`s rainfall, but an isolated rumble is possible. The overall threat exits the area by Thursday midday with high pressure building and an upper level ridge keeps the Northland high and dry for the weekend. A shortwave crosses early next week for more precipitation chances. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 649 PM CDT Mon Jun 8 2020 A warm front has moved passed most of the terminals this evening. VFR conditions were occurring at the start of the forecast. A lake breeze has moved past DLH. Not expecting any rain at most locations tonight. However, will see some showers and thunderstorms near INL by 03Z, and in the neighborhood through the rest of the forecast. MVFR cigs are possible at INL in the vicinity of stronger storms from 03Z-09Z. INL cigs will transition to MVFR from 11Z to the end of the forecast. Elsewhere, showers and thunderstorms are forecast to develop/spread across the rest of the terminals, mainly after 12Z. Look for LLWS tonight at HIB/DLH/BRD after 03Z and last until near 11Z. && .MARINE... Issued at 1009 PM CDT Mon Jun 8 2020 Northeast winds will continue over western Lake Superior tonight into Tuesday. The pressure gradient over the lake will tighten during the day and winds will strengthen to 10 to 15 knots. The remnants of Tropical Storm Cristobal are forecast to move northward through Wisconsin and into northern Ontario Tuesday night and Wednesday. Wind speeds and gusts will increase overnight and remain strong Wednesday. Wind direction will back northwesterly and eventually southwesterly as the surface low passes across the region. Small Craft Advisories may eventually be needed. && .PRELIMINARY POINT TEMPS/POPS... DLH 60 78 54 62 / 10 80 90 80 INL 66 76 51 60 / 70 90 80 70 BRD 67 80 53 63 / 30 90 80 70 HYR 64 87 56 67 / 0 90 100 80 ASX 63 82 54 67 / 0 80 90 80 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ MESOSCALE UPDATE...Huyck SHORT TERM...Wolfe LONG TERM...Wolfe AVIATION...GSF MARINE...Huyck
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
428 PM EDT Mon Jun 8 2020 .DISCUSSION... Another day of outstanding early June weather around SE Michigan extends through tonight thanks to slowly departing surface high pressure and the sharp upper level ridge just to the west. This configuration maintains mostly clear sky with light SE balancing any extra radiatonal cooling while surface dewpoint remains in the upper 40s to lower 50s. Guidance low temperatures look on target with offerings in the mid to upper 50s outside of metro Detroit leading to a rapid morning rebound toward highs around 90 Tuesday afternoon. Surface dewpoint is projected to just begin reaching the lower 60s by late in the day which suggests this round of mid summer heat will not be enhanced much by humidity before increasing clouds take the edge off toward evening. Moisture, surface and aloft, really starts to ramp up Tuesday evening ahead of Cristobal. Model soundings show precipitable water already near 1.5 inches by 00Z and only surging upward from there as the evening progresses. The surface low positioned over northern IL is ideal for directing strong moisture transport into Lower Michigan as the low level jet ramps up. RAP model soundings from the 15Z run advertise PW reaching near 2.2 inches by 06Z Tuesday night with tropical moisture charcteristics also reflected in k-index of 41 and 700 mb dewpoint near 10 C at times. These parameters are solid support for locally heavy rainfall while concerns for flooding are eased somewhat by the progressive nature of initial activity that sets up generally west to east while moving south to north over the region. The other concerning aspect of conditions for Tuesday night is the wind profile associated with Cristobal and the warm front it brings into the region. The combination of backed low level wind and the strong low level jet produce SRH exceeding 300 m2/s2 at times during the night to supply potential for rotation in any discrete surface based convection. The surface based aspect is where predictability is low given the wide range of model sounding depictions showing differing extent of neutral and deep moist adiabatic profiles combined with several high res runs that offer surface based instability during the night. For now, it looks like the leading surge of moisture will be more elevated Tuesday evening followed by a near surface based cluster of convection later in the night coincident with the surface warm front. This would be the activity most worthy of the SPC day 2 marginal risk mainly for damaging wind but also including an isolated tornado threat toward sunrise Wednesday. Complex high intensity interactions continue during Wednesday between the Cristobal low and the next system developing rapidly over the central Plains. The enhanced gradient wind is the main concern for SE Michigan as warm sector boundary layer mixing deepens through daytime heating. Wind gusts topping 40 mph look solid based on model soundings and plan view model forecasts of the wind field up to 850 mb. The warm sector also sets up an instability axis for the approaching cold front to focus storms Wednesday afternoon. The timing of the frontal passage during peak heating will be somewhat of a moving target for severe thunderstorm potential in our area. There is a late afternoon component in model solutions that activate the prefrontal trough and a late evening component in solutions that show the primary cold front having greater instability and forcing associated with the trailing upper level circulation. Evolution of the larger scale upper air features and progression of the low level moisture/instability axis favors late afternoon/early evening initiation on the prefrontal trough. The upper low will be capable of supporting additional activity along the cold front but likely not with enough moisture/instability for stronger storms later Wednesday night. Windy conditions continue into Thursday as the low pressure systems merge more into larger scale/full latitude trough with a large and deep surface low near James Bay. Deep northwest flow sets the stage for dry and cooler weather to finish the week and start next weekend. && .MARINE... Discontinuous area of high pressure over southern Ontario will maintain favorable boating conditions this evening with southeasterly flow. The stable airmass will drift eastward overnight as the remnants of TS Cristobal push northward into the upper Mississippi River Valley on Tuesday. Winds will increase while becoming southerly as the associated warm front encompasses the region brining the potential for scattered thunderstorms and locally higher waves. Small Craft Advisories may be needed Tuesday night. The remnants of TS Cristobal will then take a northeast turn and track along the western shore of Lake Michigan early Wednesday morning with impacts extending into the central Great Lakes. A Gale Watch has been issued for southern Lake Huron and Saginaw Bay as the system`s center crosses the Upper Peninsula late in the day. There is still some uncertainty as to the exact track of the storm on Wednesday which may affect future timing/gust revisions. Gusts to gales appear possible over all marine areas Wednesday with perhaps gusts just shy of 40 knots over Saginaw Bay and portions of Lake Huron, even with weak low-level stability noted in forecast soundings. Showers and thunderstorms with heavy rain will accompany this system before tapering off Wednesday night with diminishing southwest flow. && .HYDROLOGY... Showers and embedded thunderstorms are likely Tuesday night into Wednesday as the remnants of Cristobal move through the Great Lakes. The best potential for excessive rainfall with this system remains over the Midwest along the main track of the system however the system brings tropical moisture characteristics to the pattern over Lower Michigan as well. The main difference is that each wave of activity will be progressive in a south to north motion over the area Tuesday night and from west to east focused on a cold front Wednesday night. The tropical moisture supply is expected to result in locally heavy downpours and efficient rainfall production, especially in any thunderstorm complex. At this time, it appears that minor flooding of poor drainage and other prone areas is the most likely hazard. Basin average rainfall for creeks and streams is expected to hold in the quarter to half inch range Tuesday night. Additional showers and storms Wednesday into Wednesday evening may bring storm total precipitation to around an inch in the Tri Cities region with lesser totals around a half inch farther southeast through the remainder of southeast Michigan. && .PREV DISCUSSION... Issued at 124 PM EDT Mon Jun 8 2020 AVIATION... Favorable aviation conditions persist this afternoon into tonight as a strong upper ridge dominates the Great Lakes region. Few high clouds linger in the vicinity while sfc winds remain light and generally out of the southeast. DTW THRESHOLD PROBABILITIES... * None. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Gale Watch from Wednesday morning through Wednesday evening for LHZ421-422-441>443-462>464. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ DISCUSSION...BT MARINE.......KK HYDROLOGY....BT AVIATION.....TF You can obtain your latest National Weather Service forecasts online at
National Weather Service Sioux Falls SD
628 PM CDT Mon Jun 8 2020 .UPDATE... Issued at 628 PM CDT Mon Jun 8 2020 Towering cumulus have begun to form just south of the South Dakota and Nebraska border near Gregory and Charles Mix counties. We are expecting new cells to develop in this area by 7 PM. Per the RAP 0-6 km shear is from 50-60 kts in this area - with MLCAPE from 2000-2500 J/kg. With storms expected to remain discrete through 8 or 9 PM, this is more than adequate to support the development of supercells for the next couple of hours. The storms are forming behind the cold front so the initial threat will be very large hail...perhaps as large as 2 inches. New storm development is also expected farther north toward Mitchell and Huron by 8 PM. Toward sunset, storms may being to also grow upscale and bring an increasing wind threat as DCAPES in this area are from 1000-1200 J/kg. The severe threat will persist well after sunset. Have also issued a flash flood watch for areas west of a Tyndall to De Smet SD line. With the front only slowly moving east multiple rounds of thunderstorms are likely through 12Z Tuesday in this area with rainfall of 1-3 inches possible. In addition, some storms may produce rainfall rates in excess of 2 inches per hour for brief periods also posing a flash flood risk in poor drainage areas. && .SHORT TERM...(This Evening through Tuesday) Issued at 249 PM CDT Mon Jun 8 2020 The main concern in the short term is the severe weather and flash flood threat this evening into early Tuesday morning. At 19Z, a surface front extended from near Huron to Lake Andes. A large area of capped cumulus has formed ahead of the front. Despite the clouds, just ahead of the front, temperatures have warmed into the mid to upper 80s and should approach near 90 later this afternoon. Behind the front, temperatures are in the mid 70s to lower 80s. RAP soundings indicate a cap remains in place across north central Nebraska into southeastern South Dakota. Ahead of the front, the cap is unlikely to be broke. However, with the approach of a weak upper wave around 22Z, large scale ascent will help to erode the cap near the SD/NE border in the vicinity Ainsworth. In addition, cyclogenesis in northern Kansas is resulting in backing surfaced winds over southern Nebraska which is beginning to increase convergence. Expectation that increased convergence and weakening cap will result in convective initiation from 22Z- 00Z in north central Nebraska and then spread north during the evening. 0-6 km shear just behind the front is 45-60 kts with MLCAPE from 1500-2500 J/kg. Initial cells will be discrete and at least a few supercells should develop as depicted by multiple runs of the HRRR this morning and afternoon. With 0-1 km shear 10 kts or less, tornadoes are unlikely although boundary interactions could lead to a couple of tornadoes. The bigger threat will be large hail - perhaps as large as 2-2.5 inches with the strongest cells during the evening. With downdraft CAPE > 1000 J/kg, damaging winds will also be possible. Storms will coalesce into a line during the evening. With deep southerly flow, storms will tend to train over the same area from south central South Dakota toward Huron and De Smet. Few, if any storms, are expected to reach I-29 overnight with the front expected to remain west of the area. In fact, as storms become more elevated, they are likely to develop farther west toward Gregory and Chamberlain later tonight. With convection expected to extend through the night, rainfall of 1-3 inches is expected from Huron toward Lake Andes with local amounts approaching 4 inches possible. As convective initiation gets closer and we ascertain where the heavy rain is most likely, we will likely issue a flash flood watch. The boundary will slowly move east through the area Tuesday. Ahead of the boundary, temperatures will initially warm into the 70s but once the front goes through and northwest winds increase, cooler air will move into the area. In fact, temperatures will likely fall during the afternoon in many places along and east of I-29 which is rare for June. While rainfall rates will decrease, showers and a few thunderstorms will continue much of the day bringing up to another inch of rain west of I-29. The other weather concern will be the remnants of Tropical Storm Cristobal. While the center of circulation will stay in the Mississippi Valley, most of the rain will be west of the track. Some of that rain may get as far west as Highway 71 or even Highway 59 in Iowa and Minnesota on Tuesday. While the heaviest rainfall will be closer to I-35, portions of northwest Iowa and southwest Minnesota could see up to a half inch of rain. There is uncertainty on how much rain will fall from the I-29 corridor into southwestern Minnesota. Some showers and storms will move across this area Tuesday afternoon and evening - but these may be weakening so that rainfall may be much lighter. This area is most likely to see around 1/2 inch of rain but there is the possibility of even less rain should showers west of I-29 weaken more quickly than currently forecast. Finally winds on Tuesday will become fairly strong behind the front. 925 mb winds of 30 to 40 kts are expected so that winds may gust to 40 mph during Tuesday afternoon. .LONG TERM...(Tuesday Night through Monday) Issued at 249 PM CDT Mon Jun 8 2020 With the active short-term, have generally gone with model consensus for Tuesday night through next Monday. Showers will gradually end on Wednesday. In fact several deterministic models as well as a majority of the SREF members are showing rain ending by early Wednesday morning. Winds will remain gusty Tuesday night into Wednesday with gusts at or above 40 mph possible along and east of I-29. Dry weather is then expected into the weekend with temperatures gradually warming back above normal into the 80s by early next week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 440 PM CDT Mon Jun 8 2020 Showers and thunderstorms are expected to develop west of Interstate 29 overnight, and a few of these storms could be severe through 06Z. In addition, heavy rain will be likely with the storms during the period. The showers, along with isolated thunderstorms, will begin to slide eastward on Tuesday bringing rain to the remainder of the area. Gusty southerly winds this evening will diminish during the late evening, though winds could be gusty in the vicinity of thunderstorms. As a frontal boundary works across the area through Tuesday, northerly winds will increase with the passage of the front. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Wind Advisory until 7 PM CDT this evening for SDZ040-056-062-067- 071. Flash Flood Watch through Tuesday morning for SDZ038-039-050- 052>054-057>060-063>065-068. MN...Wind Advisory until 7 PM CDT this evening for MNZ071-072-080-081- 089-090-097-098. IA...Wind Advisory until 7 PM CDT this evening for IAZ001>003-012>014- 020>022-031-032. NE...Wind Advisory until 7 PM CDT this evening for NEZ013-014. && $$ UPDATE...Schumacher SHORT TERM...Schumacher LONG TERM...Schumacher AVIATION...JM
Area Forecast Discussion
National Weather Service North Platte NE
718 PM CDT Mon Jun 8 2020 .SHORT TERM...(This evening through Tuesday night) Issued at 230 PM CDT Mon Jun 8 2020 The HRRR and NAMdng model wind gust products both show high wind criteria Tuesday. The NAM indicates winds of 65kts at h800mb, the top of the mix layer as indicated in Bufkit. These strong winds are emanating from strong Pacific high pressure building through the Rockies in the wake of 995mb low pressure across KS. The wind forecast uses the guidance blend and a High Wind Warning is in place across swrn Nebraska beginning early Tuesday morning and ending Tuesday evening. The POP and temperature forecast uses the short term model blend. High temperatures Tuesday came in with upper 50s to lower 60s. These are near record low highs and North Platte could tie or break the previous record of 58 set in 1895. There is little change in the POP forecast tonight through Tuesday except that the storm system is slower and producing a prolonged period of warp-around rain Tuesday associated with an inverted h700mb trof across Nebraska, deformation and mid level frontogenesis. Postfrontal elevated thunderstorms are in the forecast along the h700mb warm air advection zone. Severe storm development late this afternoon and this evening revolves around storms firing on a sfc front draped across ncntl Nebraska this afternoon. MLCAPE of 2000-3000J/KG and 45-50kt winds at h500mb will fuel the expected development of supercells. The RAP model indicates moderate CAPE and shear with no cap by 22z. The RAP also indicates a zone of very strong sfc warm air advection developing across wrn KS this afternoon, aimed at ncntl Nebraska. This warm air advection should continue throughout the evening hours as a triple point forms near Goodland KS. .LONG TERM...(Wednesday through Monday) Issued at 230 PM CDT Mon Jun 8 2020 Dry weather is in place Wednesday through Monday with just an isolated thunderstorm chance Saturday night through Monday. The anomalous storm system affecting Nebraska tonight and Tuesday will phase with Tropical Depression Cristobal and be located across the Great Lakes Wednesday. Pacific high pressure will build through Nebraska Wednesday and Thursday. The Great Lakes storm will deepen to around 983 mb and pull a batch of Canadian high pressure south through the Midwest Friday and beyond. This will present little opportunity for return moisture across Nebraska until Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 716 PM CDT Mon Jun 8 2020 Thunderstorms ongoing this evening from near KLBF northeast to near and east of KANW. Some of these storms will be severe and contain large hail, damaging winds, with an isolated tornado possible. An advancing cold front will also bring northerly winds up to 45 kts after 09Z and continuing through the day Tuesday. Heavy rainfall is also occurring this evening, which will cause reductions in visibility at times. && .HYDROLOGY... Issued at 230 PM CDT Mon Jun 8 2020 The short term model blend, the NAM, HRRR and RAP models continue to advertise very heavy rainfall this evening associated with the formation of a closed h700mb low across KS and a slow moving cold front across Nebraska. Rain and elevated thunderstorms will continue Tuesday as this upper low moves slowly east through KS. The rain should end late Tuesday evening. These models all suggest a heavy rain center will occur somewhere across ncntl Nebraska tonight with 4 or more inches by Tuesday morning. The Flood Watch for Custer county has been expanded north to include most of north central Nebraska east of highway 83. WPC has been suggesting high precipitable water, rainfall efficiency, training, back-building and continued moisture flux for a few forecast cycles across this area. && .LBF WATCHES/WARNINGS/ADVISORIES... High Wind Warning from 4 AM CDT /3 AM MDT/ to 9 PM CDT /8 PM MDT/ Tuesday for NEZ056>059-069>071. Flood Watch through Tuesday morning for NEZ006>010-026>028-038. && $$ SHORT TERM...CDC LONG TERM...CDC AVIATION...Roberg HYDROLOGY...CDC
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
558 PM CDT Mon Jun 8 2020 .SHORT TERM... (Through Late Tuesday Night) Issued at 216 PM CDT Mon Jun 8 2020 The main focus will be around the remnants of Tropical Storm Cristobal. The latest analysis shows the depression centered over southeast Arkansas, rotating slightly west of due north. Visible satellite imagery shows the outer banding of high clouds reaching into northern Missouri and central Illinois with the expansive broken/overcast shield reaching southern Missouri and southern Illinois. The latest radar mosaic places a large shield of rain across central sections of Arkansas with the northern most banding not yet reaching the Missouri/Arkansas border. Slightly slower northward progress was cause for trimming initial precipitation chances over southern sections of the forecast area late this afternoon. The onset now looks more likely to be after 22z this evening. Recent SPC mesoanalysis shows around 1000 J/kg of CAPE running just north of the rain shield with effective bulk shear approaching 50 knots. The main concern with the onset is for developing cells in a west-to-east banded structure over southern Missouri. Individual cell movement will likely be southeast to northwest. The main question will be in regards to how much shear and CAPE is maintained through the evening with northward movement, as RAP mesoanalysis shows a generally waning in these parameters. Nonetheless, they remain respectable and would not be surprised to see these cells rotate should they develop. Rain begins to expand over the area late tonight into the morning Tuesday over the entire area. Guidance is coming into better agreement with a slight westward shift, which would line the heaviest rainfall over the extreme western fringes of the CWA. Therefore, there was no argument to expand the watch any further. However, a broad area of PWAT values ranging from 2.0 to 2.5 inches will make for very efficient rainfall producers, no matter that location. The difference here will be in the banded structure further east of the low center and the persistent heavier rainfall across central Missouri. Rainfall totals will generally range from a half inch along and east of the Mississippi River with 1-3 inches in a north-south line over central Missouri. Locally higher amounts will result, especially over central Missouri, where tropical moisture could lay out well over 3 inches in places. The system accelerates northward on Tuesday with most operational guidance pushing the back side into northeast Missouri and central Illinois between 19z and 22z. It`s beginning to look like we could see a rather sharp cutoff to rainfall with drier being entrained into the system from the southwest, thanks in part to the upper wave over the plains. This is where questions begin to arise with additional precipitation chances late Tuesday along the cold front to the west. A few high res solutions respond by igniting showers and thunderstorms along a remnant boundary left behind Cristobal, which runs east of the next upper wave. Other solution are quiet until the arrival of a pre-frontal trough, providing time for surface based instability to recover with multiple operational solutions and HREF guidance near 3000 J/kg over southeast Missouri and southwest Illinois by 00z with around 30-40 knots of shear along and ahead of the front. This will be something to watch through the day Tuesday afternoon. Depending how the dominoes fall, we could see some strong to severe thunderstorms if things pan out right. The cold front finally pushes through Tuesday night, but we then await the arrival of the second upper wave running closely behind. This may introduce a few more light showers by early Wednesday morning. Maples .LONG TERM... (Wednesday through Next Monday) Issued at 216 PM CDT Mon Jun 8 2020 Sensible weather remains limited in the long range forecast. This involves a second upper level wave that quickly moves in behind the departing remnants of Cristobal. Much drier air that originates over the southwest CONUS becomes entrained in the system, creating an envelop for a lull in activity early Wednesday. The source region for any moisture it has to work with is pulled in from the north, largely concentrated around trough and remains relatively shallow on bufkit overviews. The likely result will be scattered shower activity around the wave from mid- morning through mid-afternoon and mostly along and north of I-70. Temperatures will be dampened by the extent of cloud cover, and northerly flow wrapping around the back side of the wave. Highs may only reach the low to mid-70s. The remainder of the period looks rather inactive. A cold front drops out of the north late Thursday into Friday with limited moisture and should pass through quietly. Surface high pressure over the southern plain continues to build and broaden through the center of the country next weekend, as an upper ridge amplifies over the plains and expands eastward from Friday through Monday. Northwesterly flow aloft should remain intact, favoring near normal temperatures through the end of the period. Maples && .AVIATION... (For the 00z TAFs through 00z Tuesday Evening) Issued at 532 PM CDT Mon Jun 8 2020 Cristobal was located over southeast AR early this evening. It will move northward to near VIH by 12Z Tuesday, and to near UIN by 18Z Tuesday. Showers and a few storms will spread northward into the taf sites by late tonight with the greatest coverage near COU. The cloud ceilings will also lower into the MVFR category late tonight, and into the IFR category by early morning. Most of the showers will shift north of the taf sites Tuesday afternoon, but there may be isolated storms in the late afternoon from COU to STL ahead of an approaching cold front. VFR cloud ceilings will also return Tuesday afternoon. East-southeast winds will become relatively strong and gusty late tonight and Tuesday morning, then veer around to a southwest direction Tuesday afternoon. SPECIFICS FOR KSTL: Cristobal was located over southeast AR early this evening. It will move northward to near VIH by 12Z Tuesday, and to near UIN by 18Z Tuesday. Showers and a few storms will spread northward into STL around 06Z Tuesday. The cloud ceilings will also lower into the MVFR category around 06Z Tuesday, and into the IFR category around 12Z Tuesday. Most of the showers will shift north of STL by 19Z Tuesday, but there may be isolated storms redeveloping in the late afternoon and early evening ahead of an approaching cold front. VFR cloud ceilings will also return Tuesday afternoon. Relatively strong and gusty east-southeast winds will veer around to a southwest direction Tuesday afternoon. GKS && .PRELIMINARY POINT TEMPS/POPS... Saint Louis 74 87 66 75 / 80 100 30 20 Quincy 71 80 62 71 / 60 100 50 40 Columbia 70 84 59 72 / 100 100 30 20 Jefferson City 71 86 60 74 / 100 100 30 20 Salem 74 85 67 77 / 40 90 60 20 Farmington 73 87 61 75 / 90 100 40 10 && .LSX WATCHES/WARNINGS/ADVISORIES... MO...Flash Flood Watch from 1 AM CDT Tuesday through Tuesday evening for Audrain MO-Boone MO-Callaway MO-Cole MO-Gasconade MO- Knox MO-Lewis MO-Marion MO-Moniteau MO-Monroe MO-Osage MO- Ralls MO-Shelby MO. Flash Flood Watch through Tuesday evening for Crawford MO-Iron MO-Madison MO-Reynolds MO. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Riverton WY
954 PM MDT Mon Jun 8 2020 .SHORT TERM...(This evening through Tuesday night) Issued at 230 PM MDT Mon Jun 8 2020 Rain and snow showers have been occurring this afternoon and evening west of the Divide today as a result of the full latitudinal trough pushing across the area from the west today. Enough QG forcing appears to have influenced the enhancement of the rain and snow showers to the south over Sweetwater County earlier this morning as some of the energy to the south associated with a developing circulation near the Four Corners area begins to have an influence. The HRRR hints at two main bands of snow showers tracking southeast across the far west this afternoon associated with the main trough passage and cold advection at 700mb. Some of the snow showers in the west will continue through early this evening given the weak instability. The snow event this morning underperformed, so we are handling the rest of this late season snow event with an SPS for the potential of another 1 to 3 inches of snow across some of the western mtns above 9000 feet and 3 to 5 inches in the Tetons above 9000 feet. Impacts should be relatively minimal given the high June sun angle and intervals of sun between snow showers. East of the Divide, one rogue thunderstorm formed this morning over the Big Horn Basin along with other isolated shower activity. With the low freezing level, it didn`t take much for these other spotty weak showers to produce very small hail or ice pellets as we had one such report from Buffalo earlier today. For tonight, we have issued a freeze warning for the far west valleys and basins where low temperatures should be a couple of degrees colder tonight than last night given the clearing skies and diminishing winds after midnight tonight. Handled the expected freezing temps in Sweetwater County with an SPS as most of this zone should not get a widespread hard freeze. Although Dubois should see 30 degrees tonight, it was just as cold there last night, so handled that zone with an SPS as well. Surface cyclogenesis taking place this evening in eastern Colorado, associated with the aforementioned Four Corners upper low, will pull in more cold air from the north and will mimic a backdoor cold front across some areas east of the Divide with a wind shift to the north northwest. These winds should be most pronounced in northern Johnson County. A secondary shortwave in the northern stream will stir the winds up from the west northwest once again Tuesday. Otherwise, temperatures will begin a gradual warm up Tuesday, as a flat ridge begins to build in from the west after this next shortwave. Tuesday night should be chilly but milder than tonight. .LONG TERM...(Wednesday through Monday) Issued at 250 PM MDT Mon Jun 8 2020 Wednesday will start out with cool northwest flow and partly cloudy skies for a slight chance of showers in the northern mountains. Conditions should clear as the day progresses with the ridge axis slowly moving eastward into Idaho ans pushing the mid- level moisture to the Plains. Breezy to windy conditions will once again persist over the higher terrain and the southern half of the state. Thursday should se the ridge axis amplify and move over western WY, though 700mb temp still remain below +10C. The flow will thus turn more to the southwest, though wind speeds should be lighter for an amazingly seasonable June day. The northern mountains may see a shower or two in the late afternoon. As another strong low pressure system moves onto the West Coast, the ridge will amplify over the area and bring warmer and drier air up from the south. Friday should see temperatures warm quite a bit more with stronger south winds over much of the area. Clouds should start increasing across western WY late in the day and the low center moves into OR/WA. The warm temps, dry strong wind Friday will certainly elevated fire weather conditions across much of the area. At this time, models are showing the low center stay farther north than our current system, which will likely keep precipitation confined to the northwest mountains on Saturday, and increase the southwest wind as a strong leeside surface low develops in northeast WY. Cold air from the system is expected to move from west to east across the area Saturday night into Sunday morning. West winds will be strong with the frontal passage and are expected to continue into Sunday on the south side of the low center. Fairly zonal flow continues into Monday as more energy is expected to move from the Pacific across the northern Rockies to keep relatively dry near normal temperatures over the area with breezy wind. && .AVIATION...For the 06Z TAFS through 06Z Wednesday) West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals Showers will be over over much of the area by the start of the TAF period. Skies will also begin clearing, with clouds/mountain obscurations lingering over the northwest mountains. Winds will be decreasing by 07Z, except at KRKS, which will remain gusty throughout the TAF period. There will be a slight chance for fog near KJAC before 12Z, as clouds continue to clear. Dry conditions and mostly clear conditions will be in store after 12Z. Any precipitation will be confined well to the north over the far northwest corner of the state. Gusty winds will be prevalent between 18Z and 02Z Wednesday. East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals High clouds will begin to shift eastward after 06Z, mainly impacting KCPR. Rain showers, with MVFR conditions, will occur here through 12Z. Skies will clear at the other terminals, with winds gradually decreasing. High clouds will move back over KCOD and KWRL after 18Z, as gusty winds return to all the terminals. There is a slight chance rain showers could impact KCOD Tuesday afternoon, but most of this activity is expected to remained confined to the far northwestern corner of the state. Winds are expected to subside by 03Z Wednesday, except KRIW, where gusty winds are expected to continue through 06Z. Please see the Aviation Weather Center and/or CWSU ZDV and ZLC for the latest information on icing and turbulence forecasts. && .FIRE WEATHER... Issued AT 230 PM MDT Mon Jun 8 2020 Cool conditions will continue across the area this afternoon. Rain/snow showers will continue across the west. Rain showers and thunderstorms will spread across the south and north this afternoon, with showers continuing east and west of the Divide tonight. Gusty west-southwest winds will continue this afternoon over zones 279, 289 and 280. Winds will shift to the north northwest this evening east of the Divide. Mixing and smoke dispersal will be good to excellent east of the Divide, including zones 279 and 289, and poor to fair elsewhere. Freezing temperatures will occur again tonight across areas west of the Divide. Expect a warming trend beginning Tuesday. && .RIW WATCHES/WARNINGS/ADVISORIES... Freeze Warning from midnight tonight to 9 AM MDT Tuesday for WYZ013-023-025>027. && $$ SHORT TERM...Lipson LONG TERM...McDonald AVIATION...McDonald FIRE WEATHER...Lipson