Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/16/19

Area Forecast Discussion...UPDATED
National Weather Service Aberdeen SD
937 PM CDT Mon Jul 15 2019 .UPDATE... Issued at 931 PM CDT Mon Jul 15 2019 Updated the forecast again to delay weather and pops for a couple more hours. The storms should reach this CWA within the next two to three hours. According to the time arrival tool, the current storms over Rapid City area should reach Pierre in the next three hours. Based on radar trends, as well as support from the HRRR, the timing appears spot on. If the HRRR is correct, Tuesday morning is looking pretty dry for the entire CWA. UPDATE Issued at 747 PM CDT Mon Jul 15 2019 Updated the forecast this evening to significantly delay weather and pops until at least 3Z. The past few runs of the HRRR and ECAM are even slower yet. Could easily remove, or greatly reduce pops along and north of Highway 12 late tonight into the morning hours on Tuesday as model trends support a drier outlook. The only additional concern through this evening are the multiple boundaries sliding southward from North Dakota. A couple of boundary interactions have resulted in a brief shower or two. UPDATE Issued at 628 PM CDT Mon Jul 15 2019 Updated aviation discussion below. && .SHORT TERM...(This Evening through Tuesday Night) Issued at 335 PM CDT Mon Jul 15 2019 Surface frontal zone has moved into eastern South Dakota late this afternoon with slightly drier air in behind it. Still some high heat indices in advance of it this afternoon from 95 to around 100 degrees. Therefore, will leave the Heat Advisory going into this evening. Some isolated storms have also developed along this boundary this afternoon. Otherwise, the ops models and hi-res models show this boundary remaining across our region over the next few days as upper level flow remains nearly parallel to it. The main issue will be a couple short wave troughs that will move over the region tonight through Tuesday night. There will be plenty of instability with these short waves with weak to marginal shear for scattered thunderstorms to move over the region. At this time, the severe risk looks to be marginal with maybe a few severe storms especially out west tonight and again Tuesday night. There will not be much for any wind through Tuesday night with clear to partly cloudy skies. It will remain fairly humid with highs in the 80s on Tuesday. .LONG TERM...(Wednesday through Monday) Issued at 335 PM CDT Mon Jul 15 2019 The pattern will remain active to begin the extended portion of the forecast before more quiet conditions begin to settle in toward the end of the work week. Models continue to focus on a shortwave trough moving through the region on Wednesday into early Thursday. We can expect to see another round of showers and storms, some leftover from the previous night, affect the region during that time. Strong westerly flow aloft, void of any substantial upper lvl energy, takes hold by the latter half of Thursday through Friday. This should provide a respite from the day to day convective complexes that have been moving through the region as of late. This pattern may hold into the beginning of the weekend, but then guidance disagrees on the overall upper flow pattern by the end of the weekend into early next week. They all hint at some upper troughing shifting back in across the Pac NW/Northern tier of the US with a building upper ridge across the central CONUS. Exact placement of those features remain up the air and therefore confidence in PoPs/Temps by Sunday into Monday remain low. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening) Issued at 628 PM CDT Mon Jul 15 2019 Prevailing VFR conditions are expected for all terminals through the valid taf period. A shortwave trough crossing the region later tonight into Tuesday morning could bring showers and thunderstorms. Some of these storms may affect the airports at or in the vicinity. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...SD SHORT TERM...Mohr LONG TERM...Vipond AVIATION...SD
Area Forecast Discussion
National Weather Service Columbia SC
833 PM EDT Mon Jul 15 2019 .SYNOPSIS... Slightly drier conditions should occur for the beginning of the workweek as high pressure builds. Temperatures are expected to be near to above normal. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... With loss of daytime heating the widely scattered thunderstorms have diminished and moved south of the CSRA this evening. Satellite shows cloudiness across the area additionally decreasing and do not expect any additional convection during the overnight period. With ridge of high pressure across the region, expect mostly clear/partly cloudy skies overnight with light winds. Current dewpoints range from the upper 60s to lower 70s across the northern Midlands to the lower to middle 70s across the central Midlands and CSRA. Guidance has been very consistent with overnight min temperatures. Will continue with current forecast of overnight temperatures in the lower/middle 70s. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... High pressure aloft will continue to dominate the area`s weather through mid week as the remnants of "Barry" move up the Mississippi and into the Ohio River Valley. Mostly dry conditions can be expected, but cannot rule out isolated diurnal convection. There will be plenty of low-level moisture and at least some instability due to daytime heating, and the sea breeze could also play a role each afternoon/evening. High temperatures will be in the mid to upper 90s with overnight lows in the low to mid 70s. && .LONG TERM /THURSDAY THROUGH MONDAY/... A weal trough will approach the region from the west on Thursday, shifting high pressure into the Western Atlantic Ocean. This will allow onshore low level flow to increase, thus increasing moisture and instability. Expect an increase in diurnal convective activity from Thursday into next weekend. High pressure aloft will also restrengthen over the weekend, and above normal temperatures are likely to persist. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... VFR conditions expected through the 24hr forecast period. Diurnal convection continues to diminish and should not pose a threat to any terminals overnight. Debris cloud expected to remain over the forecast area tonight but may thin out during the predawn hours. Guidance not suggesting any stratus or fog development and this is supported by HRRR and SREF guidance so will not include any restrictions. Winds will be light and variable to calm overnight then pick up from the west to southwest around 5 to 8 knots after 15z along with scattered cumulus cloud development. Isolated convection expected again Tuesday but not enough confidence in coverage or timing to include in the forecast. EXTENDED AVIATION OUTLOOK...Scattered afternoon/evening thunderstorms, with some possibilities of patchy late night/early morning stratus and/or fog, through portions of the period. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Grand Forks ND
1013 PM CDT Mon Jul 15 2019 .UPDATE... Issued at 1012 PM CDT Mon Jul 15 2019 Forecast in fine shape. Tweeked a few border pops along SD border late tonight into at least late tonight/Tues AM activity should be south of the border. HRRR keeps vsbys good tonight so will refrain from fog mention. && .SHORT TERM...(This evening through Tuesday) Issued at 259 PM CDT Mon Jul 15 2019 Storms will continue moving east and out of the CWA tonight as the upper-level forcing (considerable cyclonic vorticity advection) diminishes and the cool air mass in the wake of the FROPA settles in. Current 500-hPa model analyses further suggest that weak upper-level ridging will build in from the west, supported primarily by lower-tropospheric cold-air advection in the wake of the advancing system that brought storms through this afternoon. The cooler, drier air will also further inhibit the development of storms through Tuesday afternoon and evening, as significant amounts of the instability and moisture that were present this morning will push off to the south and east. Expect overnight lows tonight down into the lower 60s with cooler, less humid conditions tomorrow: temperatures will only reach into the mid/upper 80s with dewpoint temperature values only expected to reach into the mid-60s. Though a good bit of the energy has been shuffled out of the area, a few isolated, pop-up showers cannot be ruled out Tuesday afternoon if enough instability is achieved. Any storms that do manage to develop will likely be non-severe. Better precip chances later Tuesday night as flow returns to the west-southwest and another shortwave approaches the Northern Plains. .LONG TERM...(Tuesday night through Monday) Issued at 259 PM CDT Mon Jul 15 2019 For Wednesday through Thursday night, off and on chances for showers and storms develop as an active weather pattern continues in zonal flow aloft. Ensemble and deterministic guidance support wider coverage of rainfall developing Wed and Wed night. Showers and storms are likely during this period, especially Wed night, as muggy weather and dew points in the 60s-70s develop associated with a low pressure system propagates eastward through the Canadian and Northern Plains. Strong deep layer shear will develop during Wed afternoon and night, allowing for organized storms and potential for severe weather, but it appears to be dependent on whether early day convection across some portion of the Dakotas will allow for daytime destabilization in the immediate forecast area. Some deterministic models show additional potential for severe weather on Thu and Thu night too, as a frontal boundary sags into the forecast area from MB in the vicinity of strong deep layer shear once again. Confidence is low in the details at this time, so continue to check the forecast for updates as the week progresses. For Friday through early Saturday, a slightly cooler and drier period commences as drier air and sfc high pressure move into the region. Stronger forcing mechanisms look to reside north of the international border early in the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 702 PM CDT Mon Jul 15 2019 VFR thru the pd. West-northwest winds diminishing this evening and then light northwest on Tuesday. Not out of the question could be some fog patches late tonight/early Tuesday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Riddle SHORT TERM...DL/JR LONG TERM...BP AVIATION...Riddle
Area Forecast Discussion
National Weather Service Grand Rapids MI
819 PM EDT Mon Jul 15 2019 LATEST UPDATE... Update/Synopsis/Aviation .SYNOPSIS... Issued at 820 PM EDT Mon Jul 15 2019 - Partly cloudy tonight - Remnants of Barry could bring heavy rain to areas near I-69 Tuesday into early Wednesday - Heat returns Thursday through Saturday, it is likely those 3 days will be the hottest of the summer so far. && .UPDATE... Issued at 820 PM EDT Mon Jul 15 2019 The showers assoicated with the warm front have pushed east of the area. It would not out of the question thee storms over northern Lake Michigan could brush the area north of Route 10 early tonight but for the most part it should stay dry. I am very concerned about the remnants of T.D. Barry moving into our CWA Tuesday. We have a large area of precipitable water values over 2 inches coming into the I-94 area tomorrow and the models tend to underplay these events. The HREF probability match mean shows for 24 hour rainfall has areas over 2 inches in the I-69 area by 8 am Tuesday. Areas of up to an inch are as far northwest as southern Kent County. This will have to be watched for sure. Another disturbing aspect to this is the model sounding for our SE CWA tomorrow afternoon. The RAP model shows nearly 2500 j/kg of cape with the equilibrium level near the tropopause (45,0000 ft). There is no CIN. On top of that the LCL is around 1500 ft. Given the water in the air (over 2 inches / more than 2 standard deviations from climo) and all that cape, these could be some very wet thunderstorms. It should be noted we are in the marginal risk for excessive rain tomorrow, south of a line from South Haven to Lansing. This something we will have to watch closely. && .DISCUSSION...(This evening through next Monday) Issued at 318 PM EDT Mon Jul 15 2019 The axis of instability was pivoting eastward through the CWA at this time. The storms continue to roll east. It appears there will be a break in the activity once they clear the Mt Pleasant to Jackson region by about 430 pm. The tropical moisture lifting northward through the MS Valley will move into Southern Lower MI. It does look like the deep moisture will result in numerous showers and perhaps a few storms on Tuesday. The greatest potential will be south of a Grand Rapids to Alma line. There is an increased risk that the rain could be heavy...which will need to be monitored. Impressive heat moves in for Thursday into Saturday. The area will be in the baroclinic zone so some storms are expected as well. Northern parts of the CWA may see there temperatures impacted by the clouds/storm so we are less certain of the degree of heat up there. Some of the storms could be strong and pulse severe is possible. A 300 mb jet will be nosing eastward into the northern Great Lakes Region Thursday night into Friday which may increase the coverage and strength of the storms. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 820 PM EDT Mon Jul 15 2019 I expect solid VFR conditions through the night. However after nearly a week with little in the way of lower cigs/vsby the remnants of T.D. Barry will move into our area Tuesday. Currently there is an area of MVFR/IFR cigs over MO and E IL assoicated with this system. It will move northeast into Lower Michigan by mid morning and should remain in place into the afternoon. I am not sure at this point how far north the rain shield will get. Even so, I do believe the I-94 tafs will be solidly in the rain tomorrow. Thing is there is considerable instability even with all the low clouds and precipitation. It would seem thunderstorms are possible with this system too. The SPC SREF has a 30 pct chance of thunderstorm at 21z near I-94 Tuesday. So I have VCTS in the I-94 TAFs tomorrow afternoon. I have conditions improving by 21z but I am not sure that will really be true. One way or the other we will have to monitor this closely. && .MARINE... Issued at 318 PM EDT Mon Jul 15 2019 South to southwest winds could be gusty up around Little and Big Sable Points this evening into tonight. Close call for a small craft advisory. The southwesterly flow generally persists into the end of the week...but likely just under criteria. Waves up to 2 to 4 feet are forecasted. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM SYNOPSIS...WDM DISCUSSION...MJS AVIATION...WDM MARINE...MJS
Area Forecast Discussion
National Weather Service North Platte NE
637 PM CDT Mon Jul 15 2019 .UPDATE... Issued at 447 PM CDT Mon Jul 15 2019 The cap is weakening across ncntl Nebraska and thunderstorms have formed ahead of the forecast schedule. A new forecast is in place across ncntl Nebraska for scattered thunderstorms this afternoon through tonight. UPDATE Issued at 417 PM CDT Mon Jul 15 2019 A forecast update is in place for the cluster of storms near Thedford. A gust to 46kts has been recorded. The forecast takes the storms southeast toward Lincoln and Custer counties over the next few hours. Storm motion is toward the southeast at 15 mph. && .SHORT TERM...(This evening through Tuesday night) Issued at 200 PM CDT Mon Jul 15 2019 Satellite timing tools suggest the shower and thunderstorm activity over ern Wyoming will be located across wrn Nebraska around 21z this afternoon. This seems faster than the deterministic model timing. The thunderstorm forecast this afternoon uses the timing tool and the fastest models, the HRRR and NAMnest, as the basis for a chance of severe thunderstorms with heavy rainfall. The HRRR also suggests good wind damage potential this evening but not significant (gusts less than 75 mph). The model generated gusts are around 65 mph. The model forms a QLCS on the nose of a 40kt 500mb jet and moves it through the Sandhills at around 45 mph. An isolated supercell or two may form later this evening behind the QLCS in the deeper shear. The heavy rain forecast across the Sandhills this evening is based on storm development ahead of the fast-moving QLCS. These storms and the QLCS will merge as indicated by the NAMnest. Precipitable water will be 1.50 inches or higher across the Sandhills. The dew point forecast uses the NAM guidance plus bias correction which is the most moist data set but is still too dry. Dew points in the 60s and lower 70s should continue tonight through Tuesday night. The temperature forecast uses the guidance blend plus bias correction. In the wake of tonight`s significant thunderstorm activity, cooler outflow air from the storms will lower highs Tuesday into the 80s to lower 90s. The thunderstorm chances late Tuesday are just scattered across northern Nebraska. The models maintain a stable environment throughout the afternoon with activity just getting started in Wyoming around 21z. This activity will try and move east through nrn Nebraska but weaken as it encounters a more stable air. .LONG TERM...(Wednesday through Monday) Issued at 200 PM CDT Mon Jul 15 2019 Just isolated thunderstorms are in the forecast Wednesday through Monday but the NAMnest is firing off a line of storms late Wednesday afternoon. This is the most aggressive model. The other models are more stable with just a hint of storm activity shown in the SREF. The latest model consensus continues to show low pressure anchored over the central high Plains but swrn and ncntl Nebraska will be in the warm sector with a warm front near the SD border. This should support heat wave and possibly heat advisory conditions at times Wednesday through Saturday. The latest model blend features highs in the 90s through Saturday, even north of the weak frontal boundary. Temperatures at h700mb continue in the 15C-18C through Saturday, even across nrn Nebraska. This could support highs in the low 100s as indicated by the ECM. Both the GFS and ECM indicate a significant cold front late Saturday which cools high back into the 80s Sunday and Monday. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 637 PM CDT Mon Jul 15 2019 In the near term, convection is on-going across north central Nebraska. Gusty erratic winds have been the primary concerns, but we`ve also received reports of marginal hail and limited visibility with the storms. Going forward, expect similar conditions to impact north central NE terminals if impacted by these storms. Outflow from this convection has largely stabilized the region to the south and west. The effects from the outflow on the projected overnight convection are still uncertain, so will go with the latest CAM guidance and continue a mention of strong storms into the overnight that could impact any/most west central NE terminals with heavy rain, limited visibility, gusty wind and hail. Otherwise, updates to the wind are expected as the outflow has caused a brisk northerly wind. There is uncertainty as to how low this outflow influenced wind will last at KLBF, so expect an update. && .LBF WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM CDT this evening for NEZ007. && $$ UPDATE...CDC SHORT TERM...CDC LONG TERM...CDC AVIATION...Jacobs
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
808 PM CDT Mon Jul 15 2019 .UPDATE... 805 PM CDT The main change to tonight`s forecast was to slow the northward spread of rain chances and bump up wind speeds through mid evening. All else looks good. The remnants of tropical cyclone Barry continue to inch their way northward. What was a fairly widespread rain shield up to I-70 in downstate Illinois early this afternoon has since weakened considerably. This looks to be due to 1.) fairly substantial ridging in both the upper and lower levels across central Indiana into central Illinois and 2.) the broadening circulation of Barry providing for less of a focus of positive vorticity advection and ascent. The 00Z ILX sounding sampled a 1.85 inch PWAT with southerly flow to above 700 mb, so when better forcing arrives it should result in an increase in shower coverage. That forcing for ascent does look to arrive overnight, with a 35-40 kt 700 mb jet per VWP data and seen on satellite lifting northward from the Lower Mississippi Valley. While convective allowing and high- res models in general look to be overdone in their northward push of QPF given current trends, do think the shower uptick forecast overnight is representative of at least the trend that should materialize over the southern CWA. The earlier mentioned ridging in central Indiana to central Illinois did result in an increased pressure gradient over the CWA late this afternoon, and a notable increase in wind speeds. Several sites have gusted to 30 mph since 4 pm, and have increased wind speeds through 10 pm, with a tapering from now until then from south to north. Just looking ahead to Tuesday, as noted in the afternoon AFD it could provide quite the sharp divide in showers from northwest CWA to southeast CWA, with potential for as high as categorical PoPs needed southeast (NW IN) and nothing needed in the northwest. Also, for along/east of I-55, where WPC does have a marginal risk of excessive rainfall, the RAP and NAM have plentiful low to mid- level moisture (e.g. 700 mb dew points of 5-8C) and some pockets of persistent convergence for slow movement or regeneration / percolating showers. So while thunder may be far from prevalent, very isolated 1.5+ inch rain amounts could occur. MTF && .SHORT TERM... 246 PM CDT Through Tuesday... Isolated shower/thunder potential through the remainder of the afternoon is the initial concern this forecast period followed by rain/shower trends this evening through Tuesday with the remnants of tropical system Barry. Modest instability has developed across the area this afternoon with some capping still in place. Satellite shows the leading edge of the cloud shield from the remnant low moving northward across the far southern CWA with a generally shallow cu field developing ahead of it. Recent radar imagery shows a few isolated showers forming across McLean and Ford Counties. Expect that more of this type activity will occur for areas south of Interstate 80 into early evening. With expanding mid and high cloud shield, relatively low instability and lingering inhibition do not expect extensive development to occur and individual cells may be rather short lived. May not even see lightning with these cells. The primary rain shield continues to make steady progress to the north and should reach the far southern CWA early this evening though it may slow somewhat before it does so. Bands of rain/showers will continue to move northward through the evening and have increased pops. The northern extent continues to be a bit tricky and have expanded precip chances northward somewhat into the northern Chicago metro and back along I-88 corridor. Thunder chances are on the low side through the evening but should increase through the overnight from south to north. By later Tuesday morning, the system will be pivoting more to the east and the primary corridor for showers will be pivoting east as well focusing from roughly the central or southern Chicago metro back to the Pontiac area. May see a relative lull in precipitation activity around midday across the Illinois part of the area but may again increase toward mid afternoon as clouds break up and instability builds. High temperatures will be cooler than today thanks to extensive cloud cover with southeastern areas seeing highs in the lower 80s and northwest areas seeing highs in the mid 80s. MDB && .LONG TERM... 305 PM CDT Wednesday through Monday... The common Midwestern mid-summer hazard of heat was the focus for this period, with heat headline worthy conditions likely within Thu-Sat and quite possibly all three days. If indeed that long of stretch, especially for the urban heat island of Chicago, than a Excessive Heat type headline would probably be needed over an Advisory. Otherwise some thunderstorm chances exist during primarily the beginning and end of this hot period, and as common on the periphery of a heat dome, some organized severe storms would be possible. On Tuesday night, the remnant wave of once tropical cyclone Barry will be shifting up the Ohio River Valley, with still a scattering of showers and maybe some thunderstorms possible into the evening. A northern stream system well north of the region will extend a decaying cold front into the Great Lakes as well by Wednesday morning. This feature will stall with pretty light flow on Wednesday allowing for lake breeze development during the afternoon. With 850 mb temperatures closing in on 20C, highs around 90 inland look on track. Global guidance continues to indicate a fairly strong northern stream wave racing from the Upper Midwest into the Great Lakes on Wednesday night/Thursday morning. The setup is one Wednesday night for organized convection (probable MCS) riding along the low- level jet nose. The trend on this has been more north, but outflow or other effects from this could spread into northern Illinois early Thursday before a more stout capping regime settles in. Then the hot weather pattern looks to establish itself. This is characterized by 1.) substantially broad upper ridge with 500 mb heights over 590 dam, 2.) strong thermal ridge leaning over into the area with 850 mb temperatures peaking mid 20s Celsius, 3.) southwest low-level flow that`s modest in the 925-850 mb level to continue to replenish the anomalous ridge, 4.) synoptic dew points of mid 70s favored (mixing potential does exist though), and finally 5.) a regime to stunt convection in the area and upstream of it. With the 850 mb temperatures forecast around 25C by both the EC and GFS on Friday, late July climatology supports upper 90s with that. Have inched up highs a tad on Friday solidly into that category which is the 24-hour period with the highest confidence in heat during the day and a very mild night. Dew points are a challenge and will likely be even in the short term for the end of the week. It`s possible the model schemes are a bit aggressive on dew points given the maturity of evapotranspirating crops in the Corn Belt are behind climatology due to the wet spring impacting planting. But that said, Barry`s remnants brought up mid 70s dew points further north and some of this will likely be tapped during this hot episode. Afternoon mixing of the dew points will probably happen some, as the boundary layer on forecast soundings has good unidirectional southwest flow and warms up quickly. Tried to account for that slightly more than what guidance has. Forecast heat index readings fall out primarily 105-110 Thu-Fri, and 100-105 now for Saturday. There is a sign of a frontal boundary/composite outflow creeping southward near the Wisconsin/Illinois state line Saturday, but that trend is less so than 24-hours ago. Will continue to message the heat, gradually ramping this up given the high confidence that some form of headline will likely be needed area wide, again centered on Friday but currently forecast Thursday-Saturday, with Sunday being possible. MTF && .AVIATION... For the 00Z TAFs... Concerns: - rain potential overnight through Tuesday morning - timing of MVFR cigs late tonight and Tuesday morning - potential for IFR cigs Tuesday morning - potential for isolated TSRA Tuesday afternoon/evening Southwest winds continue across the terminals with gusts of 25 to 30 kt. Expect that gustiness should diminish closer to sunset, but still maintain a southwesterly direction. Cloud cover will gradually increase through the evening as the remnant tropical system continues to slowly track north through the Mississippi Valley. Latest radar imagery indicates that the northern edge of the associated pcpn continues to slowly edge north, but a bit slower than previously anticipated. The airmass across nrn IL/IN, ahead of the remnant tropical system has seen sfc dewpoints drop some with deep mixing associated with the stronger wind gusts as well as some compensating subsidence that frequently occurs in advance of an approaching tropical system. Still expect that rain and mvfr cigs/vis will still reach the Chicago area terminals, but have some concern that the lowering conditions may be a bit slower than currently forecast. There is a chance that the RFD area may see some isolated showers, but still expect mvfr/ifr cigs for the early morning hours. Latest guidance suggests that the main area of moisture associated with the remnant tropical system will move into nern IL/nwrn IN during the afternoon/evening hours, bringing a chance for at least some scattered showers and thunderstorms. So, have added a prob30 for tsra for the Chicago area terminals. RFD may miss out on the pcpn as moisture begins to be shunted to the northeast by late afternoon/early evening. So, have gone with a dry forecast for RFD for tomorrow afternoon. && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ VISIT US AT HTTP://WEATHER.GOV/CHICAGO (ALL LOWERCASE) FOLLOW US ON FACEBOOK...TWITTER...AND YOUTUBE AT: WWW.FACEBOOK.COM/NWSCHICAGO WWW.TWITTER.COM/NWSCHICAGO WWW.YOUTUBE.COM/NWSCHICAGO
Area Forecast Discussion
National Weather Service Little Rock AR
730 PM CDT Mon Jul 15 2019 .AVIATION...16/00Z TAF CYCLE The remnants of Barry wl cont to move sloly acrs N AR into Tue. Rain chances wl linger ovr much of the FA tngt into Tue, with VFR/MVFR conds expected. Like the previous night, IFR conds wl return to most locations late tngt into Tue mrng. Convection is progged to form over parts of S AR late tngt, but still some uncertainty regarding initiation and coverage. Most locations wl see improving flight conds later in the PD. /44/ && .PREV DISCUSSION...(ISSUED 245 PM CDT Mon Jul 15 2019) Short Term...Tonight thru Wednesday... TD Barry is presently over the area, and is presenting a unique forecast challenge for tonight thru tomorrow. NAM last night started indicating a band of heavy rainfall across southwest AR, which was met with some skepticism. However, 12Z models jumped on that trend with quite a bit of consistency showing heavy rain in a training band curving around the southwest side of Barry, and up to the NE. HRRR and RAP are continuing to show some variation of that trend from run to run. I literally have 9 models displayed on the screen in front of me that are showing some variation of this scenario. Some models are indicating in excess of 10" of rainfall along a narrow band of heavy rainfall overnight into tomorrow morning. I have worked a number of post-landfall tropical events over 25+ years and never encountered a scenario quite like this, and I do have some concerns about the magnitude of rainfall being forecast by many of the models. There is a fair amount of low level convergence expected on the southwest side of Barry, and the development of a low-level jet will further enhance this event. Existing flash flood watch covers only eastern parts of the forecast area. With all things considered, I am issuing a flash flood watch for the southwestern and southern counties, extending up to the northeast for the next 24 hours. Ultimately I think this band of training convection will be fairly narrow, but I have quite a bit of uncertainty as to exactly where this will set up. With that said, I have to paint the QPF with a fairly broad brush thru this area. For the most part I will go 5+ inches with the heaviest rainfall band overnight. Extended Term...Wednesday Night thru Monday... Compared to the short term portion of the forecast, the long term portion is rather boring with drastically different weather related impacts. Upper ridging will remain the dominant weather feature across much of the southern US with surface ridging holding firm off the SE US coast. With a primarily rain-free forecast and temperatures climbing throughout the period, heat will become a concern. Td values will remain in the upper 60s to mid 70s F which when combined with afternoon temps in the 90s will provide heat indices above 100 F. Heat advisories will need to be considered for at least some portions of the forecast area nearly every day of the long term. && .LZK Watches/Warnings/Advisories... Flash Flood Watch through Tuesday afternoon FOR Arkansas-Bradley- Calhoun-Clark-Cleveland-Dallas-Desha-Drew-Faulkner-Garland-Grant- Hot Spring-Jackson-Jefferson-Lincoln-Lonoke-Monroe-Montgomery- Ouachita-Perry-Pike-Polk-Prairie-Pulaski-Saline-White-Woodruff. && $$
Area Forecast Discussion
National Weather Service Memphis TN
838 PM CDT Mon Jul 15 2019 .UPDATE...Evening Update. && .DISCUSSION... Watching a line of thunderstorms shift over the Mississippi River. Some strengthening occurred for about an hour, but more recently they have maintained their strength. One hour rainfall totals are generally 1-1.5 inches. As the line shifts slowly East, individual storms are moving North, training over the same area. We could begin to see some flooding as the line shifts out of the Delta areas, especially in poorly drained and urban areas. Showers and thunderstorms are expected to continue through the night. 30 && .PREV DISCUSSION... /issued 644 PM CDT Mon Jul 15 2019/ Skies are cloudy across the Mid-South this afternoon with temperatures ranging from the mid 70s to lower 80s. Tropical Depression Barry continues to move slowly north across western Arkansas. As the remnants of Barry continue to move north tonight, more showers and isolated thunderstorms will move through the Mid- South. Some of the showers may produce heavy rainfall so the Flash Flood Watch will continue for most of the region. Some minor changes have been made so a few counties in the eastern sections of the Mid-South will no longer be in the watch. Temperatures will be a little cooler than normal with lows Tuesday morning in the lower 70s. The remnants of Barry should reach central Missouri by Tuesday and will continue to move northeast. More showers and isolated thunderstorms are expected with locally heavy rainfall possible so Flash Flood Watch will remain in effect. Temperatures will be warmer on Tuesday with highs in the mid to upper 80s. As the remnants of Barry move farther east Tuesday night, there will be a gradually ending of the showers from west to east. Temperatures will be similar to tonight with lows Wednesday morning in the low to mid 70s. On Wednesday, the remnants of Barry are expected to move east with only a small chance of showers across the Mid-South. Temperatures will be warmer on Wednesday with highs in the upper 80s to lower 90s. A few locations across east Arkansas could see heat index value approach 105 degrees. An upper level ridge will start to build into the area Wednesday night and remain over the region into the weekend. Dry weather is expected Wednesday night through Thursday night. Scattered afternoon thunderstorms will be possible Friday and Saturday mainly over north Mississippi. Temperatures will warm into the lower 90s during this period with heat index values likely exceeding 105 degrees over much of the Mid-South. Afternoon thunderstorms may become more widespread on Sunday and next Monday. ARS && .AVIATION...00z TAF Cycle TD Barry will continue to bring multiple rounds of SHRA and TSRA to the terminals. This will continue over the next 30 hours, with a mixture of VFR and MVFR conditions throughout, with intermittent IFR possible. VCTS will begin the period for the first 2 to 6 hours as storms continue to move in from the SW. Latest HRRR guidance suggests this will end after midnight, with more activity moving in by the early morning. The lowest CIGs of the period will likely be near or just after sunrise. TSRA will be possible again in the afternoon hours, but uncertainty is strong wrt timing of this activity, so kept VCTS at this time. ZDM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...Flash Flood Watch through Tuesday evening for Clay-Craighead- Crittenden-Cross-Greene-Lee AR-Mississippi-Phillips- Poinsett-St. Francis. MO...Flash Flood Watch through Tuesday evening for Dunklin-Pemiscot. MS...Flash Flood Watch through Tuesday evening for Benton MS-Coahoma- DeSoto-Lafayette-Marshall-Panola-Quitman-Tallahatchie-Tate- Tunica-Yalobusha. Flash Flood Watch until 7 AM CDT Tuesday for Calhoun-Chickasaw- Pontotoc-Tippah-Union. TN...Flash Flood Watch through Tuesday evening for Crockett-Dyer- Fayette-Gibson-Hardeman-Haywood-Lake-Lauderdale-Madison- Obion-Shelby-Tipton-Weakley. && $$
Area Forecast Discussion
National Weather Service Topeka KS
601 PM CDT Mon Jul 15 2019 ...AVIATION UPDATE... .SHORT TERM...(This evening through Tuesday) Issued at 334 PM CDT Mon Jul 15 2019 As of 20Z Monday afternoon the remnants of Hurricane Barry continue to progress northward through the MS River Valley. At this hour the center of the midlevel low was across northwest AR. An expansive stratocumulus field has developed across eastern KS as low-level moisture streams northwestward on the northern periphery of the midlevel low. A stout EML above 850 mb should preclude any shower/storm development this afternoon and early evening. In addition, the increased cloud cover has tempered temperatures a bit with highs ranging from the low 90s in the west and low to mid 80s across far eastern KS. A quiet night is expected area-wide with cloud cover rotating across eastern KS as the midlevel slowly ejects northward. Overnight lows will reach the upper 60s tonight. The warming trend ensues tomorrow as the remnants of Barry pushing eastward while the midlevel ridge expands across the central US. An attendant 850 mb thermal ridge will overspread the the Central Plains with 850 mb temperatures 21-25 C tomorrow afternoon -- translating to surface temperatures in the low to middle 90s. Factoring in dew points in the upper 60s to near 70 will result in heat indices in the 100 to 105 range, especially across central and north central KS. .LONG TERM...(Tuesday night through Monday) Issued at 334 PM CDT Mon Jul 15 2019 The heat will further build Wednesday through the remainder of the week into the weekend as the aforementioned thermal ridge overspreads the area. Associated 850 mb temperatures are expected to range from +24 to +29 C, translating to surface temperatures in the mid 90s to low 100s. With little change in low-level moisture, confidence has increase for multiple days of excessive heat. Heat indices are likely to range from 105 to 110 each afternoon Wednesday through Saturday, and possibly Sunday. As a result have issued an Excessive Heat Watch beginning at 1 PM Wednesday through 7 PM Saturday. There is a very slight chance for a shower/storm across far northern KS Wednesday afternoon as a weak midlevel perturbation rounds the ridge across NE. The persistent midlevel ridge looks to break down by late weekend into next week as a trough ejects across the Northern Plains, shunting a surface cool front through the area. GFS/ECMWF guidance suggests the most likely timeframe of the frontal passage would be late Sunday into Monday. This frontal passage could also bring the potential for showers and storms. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 601 PM CDT Mon Jul 15 2019 Models show some low level moisture from the remnants of Barry remaining over eastern KS through the night. With the boundary layer decoupling and RAP forecast soundings showing some fog potential, will include a tempo for MVFR VSBY. There could also be some stratocu persist through Tuesday morning. At this point models keep RH values more in line with scattered clouds than one would expect with a CIG. So will just keep a mention of scattered clouds below 3 KFT. The last couple runs of the HRRR have suggested convection from NEB may make a run at northern KS. Unless a strong cold pool develops and drives south, this seems unlikely with forecast soundings showing substantial inhibition with not much moisture advection into north central KS. Something to keep an eye on. && .TOP WATCHES/WARNINGS/ADVISORIES... Excessive Heat Watch from Wednesday afternoon through Saturday evening for KSZ008>012-020>024-026-034>040-054>056-058-059. && $$ SHORT TERM...Baerg LONG TERM...Baerg AVIATION...Wolters
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
957 PM MDT Mon Jul 15 2019 .UPDATE... Issued at 954 PM MDT Mon Jul 15 2019 Thunderstorms continue across portions of western South Dakota. A storm or two may produce gusts over 50 mph. With overall threat of severe storms diminishing, severe thunderstorm watch will be allowed to expire. && .DISCUSSION...(This Evening Through Monday) Issued at 209 PM MDT Mon Jul 15 2019 The latest water vapor images and RAP analysis showed southwest flow aloft across the CWA with one short-wave trough exiting western SD and another moving across ID/UT/WY/CO. The first wave has cut back on heating; thus, substantial MLCIN still exists across the CWA. Farther west across WY, the MLCIN was weaker and TCU/CB were developing across western/central WY. This activity should spread northeast tonight, bringing another round of thunderstorms to the CWA, with severe storms likely given 1000-2000 J/kg of MLCAPE and 0-6km shear of 35-45 kt. CAMs suggest that the main corridor of severe activity will be across the southern CWA, with an initial hail/wind threat transitioning to mostly wind, and perhaps some locally heavy rainfall. Another area of thunderstorms may track from southern MT/northern WY across northwestern SD later tonight. Wind profiles favor some splitting supercells through this evening. Finally, the heat advisory for Tripp County continues until 9 pm CDT today. The air mass is expected to recover a little better on Tuesday than today, and also another short-wave trough should be better timed for severe storms in the mid-afternoon through evening. A notable low-level jet and attendant warm advection/isentropic lift is progged by most models across northeastern WY and western SD Tuesday evening. This will result in widespread thunderstorms, along with the possibility of a tornado or two in northeastern WY where low-level hodographs show substantial veering. The low- level jet should then focus over northwestern SD later in the evening, which may favor locally heavy rainfall given PWs of 125-150 percent of normal and low-level frontogenesis. However, storm motions will be fairly fast, and thus have not issued a flash flood watch at this time (something for later shifts to keep an eye on). Most of the activity should shift after 06z Wednesday. The chance for thunderstorms will continue Wednesday afternoon and evening, but it appears the coverage and severe threat will be somewhat less than Tuesday. Thereafter, thunderstorm chances will be at a minimum through at least Saturday as the flow becomes more zonal with near-average temperatures. && .AVIATION...(For the 06Z TAFS Through 06Z Tuesday Night) Issued At 954 PM MDT Mon Jul 15 2019 Isolated/Scattered thunderstorms will move across portions of western South Dakota overnight. IFR conditions with the thunderstorms. Additional thunderstorms will develop across the area Tuesday afternoon and evening. Otherwise, VFR conditions expected. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...None. WY...None. && $$ Update...7 DISCUSSION...Bunkers AVIATION...7