Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/19/18

Area Forecast Discussion
National Weather Service Hastings NE
627 PM CDT Wed Jul 18 2018 .UPDATE... Issued at 626 PM CDT Wed Jul 18 2018 Just issued svr tstm watch 281 until 06Z. We cont to monitor tstms upstream and it currently appears the best chance of tstms tonight will be N of a line from ODX-GRI-JYR. We were generous with the counties in the watch to the S and W of that area because some CAMs suggest additional tstm development W of the on-going activity. We will cont to monitor the situation thru the evng...but for now the highest risk for svr tstms in the next 2 hrs is over Valley and Greeley counties. && .SHORT TERM...(This evening through Thursday) Issued at 248 PM CDT Wed Jul 18 2018 Focus of attention is on the wave moving through the northern/central Plains tonight. As of now, subsidence behind morning convection should keep us largely dry this afternoon and early evening, but convection has already developed along an area of low-level convergence in South Dakota and several models send this convection to the south tonight. Not a lot of agreement among short term models. For example, the NAMnest and NSSL WRF takes convection as far west and south as our western CWA and north central Kansas, whereas the HRRR barely clips us in our northeast. There is enough uncertainty to include nearly our entire CWA with at least a slight chance of thunderstorms, with higher chances in our northeast. Since we`ve seen a lot of sky cover, this may hinder any development here, but with strong bulk shear for July and MLCAPE of over 1000 J/kg, there is enough support for thunderstorms to propagate into our area. A tornado is not completely out of the question in our north, considering our 0-1 km helicity above 50, especially if the mode of convection will be discreet cells rather than linear, which is still a bit of a question, even in the short term. Confidence in this forecast is not all that high, as numerical models in the short term have regularly failed over the past couple of days, and there is still a shortage of agreement and consistency among them. .LONG TERM...(Thursday night through Wednesday) Issued at 248 PM CDT Wed Jul 18 2018 Warm advection type showers are still on the table for late Thursday night, and elevated instability and favorable mid-level lapse rates could aid in giving us some marginally large hail and severe wind gusts. Although the subtropical ridge builds west into the Great Basin stretching into the southern Plains, we will largely remain on the northeastern and eastern periphery which will make us vulnerable to a series of shortwave troughs, especially from the latter half of the weekend into next week. Temperatures should be rather typical for summer, with highs in the 80s and lower 90s and lows in the 60s for the most part. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 620 PM CDT Wed Jul 18 2018 Significant Wx: A brief IFR +TSRA possible tonight. Tonight: VFR...but svr tstm watch #281 is in effect until 06Z. Can`t rule out a +TSRA with G50 kt. Outside of any tstms...SE winds 10 kt or less will become VRB after 07Z. Confidence: Medium Thu: VFR with a few CU forming around midday with bases lifting to 6-7K ft. NW winds 5-10 increasing to 10-20 kt. Confidence: High && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ UPDATE...Kelley SHORT TERM...Heinlein LONG TERM...Heinlein AVIATION...Kelley
Area Forecast Discussion
National Weather Service Wilmington NC
953 PM EDT Wed Jul 18 2018 .SYNOPSIS... A weak cold front will continue to move southward along the South Carolina coastline, and will stall south of Charleston on Thursday. The front should return northward on Friday. Unsettled weather is possible Saturday through Tuesday with a chance of showers and thunderstorms each day. && .NEAR TERM /THROUGH THURSDAY/... As of 1000 PM Wednesday...With the exception of a shower near Surf City, rainfall has ended across our forecast area. I`ve adjusted PoPs downward or removed them entirely for the overnight period in agreement with the latest HRRR and RAP models, although I did hang on to isolated showers a bit longer across Darlington and Florence counties where recent convective development across the Camden and Columbia area could conceivably drift eastward. Elevated instability will persist overnight, particularly across South Carolina and offshore closer in proximity to the surface front which continues to sink southward. Discussion from 645 PM follows... A cluster of storms near Southport and another near Georgetown and the Santee River are all that`s left of today`s convection. The front appears to have been bumped southward by the convection, with either northeast or northwest winds now observed in Georgetown and Kingstree, SC. Dewpoints have fallen into the mid 60s from Kenansville to Fayetteville to Rockingham, and some of this drier air should bleed into the area overnight. Updates early this evening focused on reducing rain chances this evening (particularly across SE North Carolina) and showing a faster onset of northeasterly winds. The latest HRRR appears very reasonable currently. Discussion from 300 PM follows... The cold front has shifted into the southern 1/3 of the forecast area. Models continue to show it shifting southward to a location south of our area on Thursday. The convection has formed in two broken lines along boundaries and is moving south-southeast. The convection is expected to continue throughout the late evening hours. As dry air aloft moves into the northern 2/3 of the area the convection for Thursday is expected to be confined to a line mainly south of Myrtle Beach to just south of Florence. Lows tonight are expected to fall into the lower 70s inland to the middle 70s along the coast. Highs on Thursday will reach into the upper 80s to near 90 inland to the middle 80s at the beaches. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 315 PM Wednesday...Latest guidance suggests the frontal boundary will be quasi-stationary along the Carolina coast Thursday night and Friday. A wave of low pressure is expected to develop Thursday evening off the southern SC coast and lift north to the Outer Banks of NC by Friday afternoon. This will keep the highest PoPs through the period focused along the coast, trailing off to slight chance west of the I-95 corridor. The front may move inland across the forecast area Friday night, but the bulk of moisture will be shunted offshore as a 500 mb closed low drops into the Ohio River valley. Clouds and northeast surface flow will keep temperatures a few degrees below climo through this period. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 315 PM Wednesday...GFS/ECMWF very similar with development of mid/upper low pressure across the OH valley during Saturday. Both drop this feature southward to near AL or GA Monday and the central Gulf Coast during Tuesday. As a result, a higher precipitable water environment will likely become focused across the Carolinas with an increasing potential for showers and thunderstorms each day through the early part of next week. The increased cloud cover and southerly flow will support above normal low temperatures each night and slightly cooler than normal highs each day. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 00Z...VFR through the period. Showers near KILM will decrease by 01Z. Cloud cover will become scattered by midnight. Although winds will be light and low levels are moist, expect wind speeds to increase enough by midnight to inhibit fog formation. VFR Thursday with ENE-E winds around 10 kt. Extended Outlook...Occasional MVFR to IFR conditions due to scattered to numerous showers and TSTMs Friday through Monday. && .MARINE... NEAR TERM /THROUGH THURSDAY/... As of 945 PM Wednesday...Northeast winds have begun to increase north of Cape Fear, and should spread beyond Cape Fear to the Grand Strand and Georgetown vicinity overnight as the surface cold front continues to sink southward. Only minor changes were made to the forecast with this late evening update. Discussion from 645 PM follows... Thunderstorms this afternoon have thinned out in coverage, but remain active near Southport, Bald Head Island, and also 20-40 miles east of Georgetown, SC. The trend overnight should be for convective activity to largely end north of Cape Fear, with scattered showers and perhaps a thunderstorm offshore of Myrtle Beach or Georgetown. A cold front has been pushed southward by thunderstorm activity from around the Santee River entrance to near Frying Pan Shoals buoy. Models are unanimous that the front will continue to shift farther south overnight, with east to northeast winds increasing to 10-15 knots, strongest near Cape Fear. Seas currently 2-4 feet will change little in height overnight, but could begin to shift more toward the shorter end of the wave period spectrum due to increasing wind speeds. Discussion from 300 PM follows... A cold front has shifted just south of Little River and will continue sliding south of the coastal waters overnight. Winds will become northeast at 10 to 15 knots behind this front and will become easterly by the end of Thursday. Seas are running 2 to 4 feet this afternoon with a southwest to west fetch. Seas are expected to fall to 2 to 3 feet before increasing to 3 to 4 feet by Thursday with the northeast flow. SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 315 PM Wednesday...A frontal boundary will be located just south of the waters Thursday evening, and lift slowly northward through the period as a wave of low pressure develops off the SC coast. The low will lift north to the Outer Banks by Friday afternoon. Winds are expected to be directed onshore Thursday night, then become variable Friday as the low moves south to north across the waters. By Friday night, southwesterlies should develop in the wake of the low as the frontal boundary shifts northward. With the frontal boundary and low pressure impacting the waters through the period, numerous showers and thunderstorms are expected. LONG TERM /SATURDAY THROUGH MONDAY/... As of 315 PM Wednesday...A southwesterly fetch is expected to increase during Saturday with areas of low pressure found across the eastern U.S. and high pressure far offshore. The fetch could carry into the first part of next week resulting in a prolonged period of Small Craft conditions. Seas will likely average 4-6 ft which is not a typical mid-July sea state. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MBB NEAR TERM...TRA/DRH SHORT TERM...III LONG TERM...MBB AVIATION...MRR
Area Forecast Discussion
National Weather Service Lincoln IL
904 PM CDT Wed Jul 18 2018 .UPDATE... Issued at 903 PM CDT Wed Jul 18 2018 A strong jetstream aloft will cause a trough to dig faster east- southeastward into the mid-Mississippi valley region overnight, with associated thunderstorms spreading into the area. Latest HRRR and nam-nest models bring some thunderstorm activity into Schuyler county shortly after midnight, and spread it toward the Illinois River valley by dawn. Have therefore increased PoPs in the overnight period in this area. Otherwise, a relatively cool night on track with lows near 60 from around I-55 eastward, and low 60s to the west. && .SHORT TERM...(This evening through Thursday) ISSUED AT 210 PM CDT Wed Jul 18 2018 High pressure located over the central Great Lakes will continue to provide seasonable temperatures and humidity this afternoon and into tonight. Clouds will gradually increase tonight, as the high drifts east and a trough approaches from the upper Midwest. Scattered convection should develop Thursday morning as the trough moves into the area, with the best chance of precipitation located west of I-55. Moisture and instability will gradually increase through the afternoon and evening. While some differences exist between forecast guidance, models suggest a northwest-southeast oriented instability gradient located over the CWA. With MUCAPE values approaching 1500-2500 J/kg... and bulk shear values exceeding 30kts... at least a marginal severe threat is likely if convection can develop. .LONG TERM...(Thursday night through Wednesday) ISSUED AT 210 PM CDT Wed Jul 18 2018 Biggest concerns for this period come Thursday night through Friday afternoon as a cold front passes through Illinois. Some scattered convection is likely at the start of the period as instability continues to build eastward, with thunderstorms likely through Thursday night. A marginal severe threat may continue through the overnight hours given modest instability and shear. Forecast guidance has sped up the timing of the cold front, which is now expected to pass late Friday morning/early Friday afternoon. Scattered strong to severe storms may develop ahead of this cold front... though details are hard to work out. Best chances for storms will be in our far southeast, where better instability and shear will be in place. A few showers are expected this weekend through Wednesday as an upper level low stalls out over the Ohio Valley. Best chances for rain will be across the eastern half of the state. The upper low will gradually weaken before a ridge begins to build back into the area by mid-week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 644 PM CDT Wed Jul 18 2018 Early morning thunderstorms in the Mississippi Valley region may migrate as far east as the I-55 corridor by late morning Thursday, but VFR conditions are expected for the central IL terminals until 15Z. At that point, have included VCTS at KSPI, KPIA, and KBMI although explicit timing of thunderstorms is not possible at this point. KDEC-KCMI are expected to remain east of the thunderstorm activity through 00Z. Any thunderstorms will have the potential for strong gusty winds and localized IFR/MVFR conditions. Winds E-NE up to 8 kts overnight, becoming SE 8-12 kts after 15Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...37 SHORT TERM...Hiris/Smith LONG TERM...Hiris/Smith AVIATION...37
Area Forecast Discussion
National Weather Service Omaha/Valley NE
715 PM CDT Wed Jul 18 2018 .SHORT TERM...(Tonight through Saturday) Issued at 403 PM CDT Wed Jul 18 2018 Main forecast problem is severe weather overnight. Closed upper low is forecast to move southeast into the Mid Mississippi Valley tonight. Airmass is unstable south of a northwest-southeast warm front. Latest ML CAPE values were between 1000 to 1500 J/Kg. A north-south oriented surface trough over north central Nebraska is forecast to move slowly eastward during the evening. 0-6 Km bulk shear at 20Z is 35 to 50 knots over eastern Nebraska. Believe the scenario will be isolated storms, most likely Supercells, to occur in northeast Nebraska during the early evening. Damaging winds and an isolated tornado is possible. Then later on this evening, a complex of severe thunderstorms with damaging wind threat is expected to develop over northeast Nebraska after 03Z and move southeast across eastern Nebraska and southwest Iowa. HRRR model forecasts that the complex will be through eastern Nebraska and southwest Iowa by 11 to 12Z. After this complex moves through, dry weather is forecast through Saturday as high pressure moves in. .LONG TERM...(Saturday night through Wednesday) Issued at 403 PM CDT Wed Jul 18 2018 Below normal temperatures, with highs in the lower 80s is forecast. Another chance of thunderstorms is on Sunday night into Monday morning as a weak cold front moves southeast. This may only affect western portions of our CWA. The next system with more widespread thunderstorm activity will be next Wednesday as another cold front moves southeast in northwest upper flow. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 715 PM CDT Wed Jul 18 2018 Main aviation concern during the TAF period is the coverage and evolution of strong to severe thunderstorms that currently are ongoing northwest of KOFK. Isolated convection is expected to congeal into linear cluster of severe storms and then spread southeast across eastern Nebraska late evening and overnight. Timing into KOFK around 03z, with potential impact through 07z. Right now, looks like storms will not arrive in vicinity of KOMA until 07-08z, and will persist through 10-11 UTC. Timing into Lincoln 08-09z, with impact through 12z. Ceilings with storms will drop to low VFR or high end MVFR. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Smith LONG TERM...Smith AVIATION...Fortin
Area Forecast Discussion...CORRECTED
National Weather Service Pueblo CO
302 PM MDT Wed Jul 18 2018 .SHORT TERM...(This evening through Thursday) Issued at 243 PM MDT Wed Jul 18 2018 Drier air in the mid levels was spreading across the state this afternoon under nwly flow aloft, while n-nwly surface winds have begun to lower surface dewpoints as well. Starting to see some very isolated convection develop over wrn CO and nwrn NM as of 2030z, so will leave some very low pops in place for the higher peaks of the Sangres and San Juans into early evening, though coverage/intensity of any tsra will be sparse/weak. Still some modest instability along the KS border late this afternoon, though better instability and low level moisture convergence lie farther to the north and east of the region over KS. Past few runs of the HRRR and other mesoscale models haven`t indicated any convection in CO this evening, so will taper back pops over the plains to just a sliver of isolated near the border prior to 00z. Clouds then clear overnight with seasonably mild temps. Center of upper level high pressure drifts eastward along the CO/NM border on Thu, with hot temps across the region as mid level temps/heights peak. Should see readings well above 100f along the lower Ark Valley, with 80s/90s widespread elsewhere. Air mass continues to slowly dry under n-nwly surface/mid-level flow, and suspect at best only very isolated/weak/mainly dry convection over the higher peaks in the afternoon. .LONG TERM...(Thursday night through Wednesday) Issued at 243 PM MDT Wed Jul 18 2018 After a couple of days of hot and relatively dry weather, rain chances will be on the increase once again starting this weekend and especially into early next week. Monsoon moisture will once again be on the increase as early as Friday along the contdvd and across the entire region for the weekend into early next week. For Friday, it will be hot once again with max temps on the plains aoa 100F along the lower ark rvr valley and 90s over the remainder of the plains. Upper 80s will occur in the valleys with 70 mtns. Showers should be on the upswing across the contdvd as moisture increases. For the weekend, moisture increases all regions, although I really do not see any noticeable forcing on the plains, and showers and storms over the lower elevations may be isolated at best. Over the mtns, scattered to likely pops are forecasted. Some of this rain may be locally heavy, with the attended threats of flash flooding and rockslides. From late Sunday night into early next week, showers and storms should become widespread all regions a a front will come down the plains as early as Sunday night, and this will be the needed forcing to get storms going over the plains. flash flooding will become more a concern this period, especially urban areas and east slopes of the mtns/burn scar regions. A drier trend will likely start by mid week. /Hodanish && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 243 PM MDT Wed Jul 18 2018 VFR conditions will continue at all taf sites tonight and Thursday, as drier spreads south across Colorado. Any convection this evening and Thursday afternoon will be very isolated and high base, with tsra remaining over the higher terrain. && .PUB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...PETERSEN LONG TERM...HODANISH AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service Las Vegas NV
225 PM PDT Wed Jul 18 2018 .SYNOPSIS...Moist and unstable air will remain over the region through the end of the week providing fuel for afternoon thunderstorms... especially over the mountains. Early next week, a heatwave will be building with very hot temperatures expected. && .SHORT TERM...through Saturday. Thunderstorms in the forecast area have been confined to the Spring Mountains and central Nevada early this afternoon. Elsewhere, convection has been slow to develop in spite of Pwat values over 1.5 inches from Clark County southward and CAPE Values of 1500-2000 J/kg. Deep easterly steering flow behind the inverted trough moving across southern California will bring storms that develop over the Mogollon Rim into at least Mohave County...and possibly the Colorado River Valley and southern Clark County this evening. Conditions are less favorable for any storms that develop over Lincoln/northern Mohave counties to head into northeast or central Clark County this evening, but it cannot be completely ruled out as cold pools and outflow boundaries begin to influence convection late this afternoon and evening. So, will leave a slight chance of thunderstorms mentioned in the forecast. The HRRR has been indicating the storms will mainly be confined to Mohave County this evening. The ridge centered over central California and the Great Basin is forecast to migrate over the Four Corners Region Thursday and toward the Texas Panhandle Friday and Saturday. This will lead to lower temperatures across Inyo County and central Nevada...diminishing heat impacts going into the weekend. Also, steering flow will become southerly for any convection that gets going Thursday into the weekend. This will shut down the potential for late evening storms to move into southern Nevada from the northeast like we have seen a few times over the past week. Moist and unstable air already in place will not be flushing out, but we should see a slight decrease in thunderstorm development from west to east the next few days over southeast California and southern Nevada. Temperatures will hover near normal. .LONG TERM...Sunday through Wednesday. Strong ridge to our east progged to shift westward over Arizona early next week. Lingering moisture combined with daytime heating will still allow for thunderstorms to develop mainly along higher terrain through the weekend. The westward propagation of the high will increase temps and continue to keep thunderstorms chances mainly focused over the higher terrain. In the coming days, likely need to start considering an Excessive Heat Watch for Tuesday and beyond. && .AVIATION...For McCarran...Outside of convective influence, expect generally light winds below 10 knots favoring an east-southeast direction turning to the south-southwest this evening. Thunderstorms will continue to be possible on the surrounding higher terrain, but the probability thunderstorms and associated outflow affecting the terminal is low. CIGs should remain above 10k feet. For the rest of southern Nevada, northwest Arizona and southeast California...Outside of thunderstorm influences, winds will follow diurnal trends with speeds of 5-15 knots. CIGs at or above 10k feet in general but CIGs may drop to 5-7 k feet in shower and storms. Isolated to scattered thunderstorms through this evening will produce gusty and erratic outflow winds. Although, most of the thunderstorm activity should remain over the higher terrain, it is possible storms will move into the valleys. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Adair LONG TERM...Pierce AVIATION...Salmen For more forecast information...see us on our webpage: or follow us on Facebook and Twitter