Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/05/19

Area Forecast Discussion
National Weather Service Aberdeen SD
615 PM CDT Thu Jul 4 2019 .UPDATE... Issued at 610 PM CDT Thu Jul 4 2019 Mostly heat of the day cumulus of limited extent and mid clouds associated with southwest flow aloft, however not much to indicate that there will be much to get storms organized this evening. Indicies are low over the CWA and CAMS rather disorganized in coverage. As such, will adjust POPs to try and transition convection out west into the western CWA later this evening and across the CWA overnight. No other changes of note. && .SHORT TERM...(This Evening through Friday Night) Issued at 403 PM CDT Thu Jul 4 2019 The HRRR and NBM-DNG have done a great job indicating the diminishing weather threat from the initial storms that moved across Stanley county earlier this afternoon, into an area that had been covered by lower clouds most of the day. Have continued to hedge the forecast closer to their solutions with this forecast. The result is more scattered to isolated showers and storms for the late afternoon and early evening hours. The main concern remains across our southwestern counties, which are in a SPC Slight Risk. Hail looks to be the main threat, along with heavy rain, although strong winds or a tornado can`t be ruled out. We will continue to monitor the progression of afternoon/evening convection as it may impact community gatherings and holiday fireworks displays. PW values of 1.5 to 2in will be standard over of southern counties, with the potential for heavy rain. Saturated grounds continue, especially from south central to northeastern SD and west central MN where 1.5 to 2in fell, with several areas getting over 3in. .LONG TERM...(Saturday through Thursday) Issued at 350 PM CDT Thu Jul 4 2019 The Saturday through Thursday period model upper level flow over our region showed little to no change from previous model runs. Saturday starts out with an upper level low pressure area over the Pacific Northwest. Through the weekend, troughing digs southward into the western U.S. This upper level flow pattern will keep our region active through most of the period as short wave troughs traverse over our region bringing off and on chances of showers/storms. On Monday and Monday night, the upper low pressure area over the Pacific Northwest kicks into Canada while the southern part of the trough lifts northeast towards our region. Then for the middle of the week, upper level ridging looks to build up over the western U.S. The EC and GFS show some pretty decent 50h heights building over the western U.S. starting to nose into the western part of our region. Through the period, below normal temperatures on Saturday in the mid to upper 70s should warm to near normal into the 80s through the rest of the period. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 610 PM CDT Thu Jul 4 2019 Generally VFR conditions this evening. Storm coverage is possible but the situation looks disorganized late evening/overnight and therefore confidence is low. There may be another round of MVFR clouds that follow the weak system Friday morning. && .ABR WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. && $$ UPDATE...Connelly SHORT TERM...KF LONG TERM...Mohr AVIATION...Connelly
National Weather Service Albany NY
749 PM EDT Thu Jul 4 2019 .SYNOPSIS... Very warm temperatures will continue through Saturday with humidity levels rising. Isolated to scattered showers and thunderstorms will develop Friday mainly west of the Hudson Valley, becoming numerous areawide on Saturday. A milder and drier airmass will arrive for Sunday. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Updated at 730 pm. Very quiet weather across the area tonight with mainly clear skies and temperatures falling into and through the 70s and 60s. Convection over Pa will not be making any progress toward eastern NY tonight and PoPs will remain near zero overnight. Previous discussion is below... As of 130 pm...nudged high temps up about 2F based on current obs. Diurnal mixing has allowed dewpoints to come down, so the apparent temps will not be too much different. Previous discussion... As of 1055 AM EDT...A mostly sunny and hot Independence Day is expected this afternoon with a 1019 hPa sfc high over upstate NY, and a low and mid level ridge axis over southeast Canada and the Northeast. The sfc anticyclone will slowly drift east/southeast of the region today with a slight uptick of the sfc dewpts and humidity levels. Sfc dewpts will be in the upper 50s to mid 60s with light winds. The latest GOES-16 visible satellite picture has a few cumulus over the eastern Catskills, and the southern Greens with some scattered cirrus from the Capital Region north and east. An isolated shower may pop-up over the Schoharie Valley and eastern Catskills due to terrain differential heating, but with dry and warm air aloft due to the subsidence from the ridge, we are expecting mainly a rain free day for the majority of the forecast area. The latest 3-km HRRR and NAM support a mainly dry pm into the evening for the 4th of July festivities. We nudged forecast highs up a degree or two in a few spots with upper 80s to lower 90s in the valley areas, and upper 70s to mid 80s over the higher terrain including the hilltowns. Heat indices fall short of 95 degrees in the mid Hudson Valley. Ridging aloft and high pressure will still be in control tonight with mainly clear skies. Overnight lows will be rather muggy with mainly 60s along with some patchy fog. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Anomalously strong midlevel ridging will remain in place Friday morning with 500 mb heights around 590 dam, leading to a mainly dry start to the day. The ridging will weaken during the afternoon and evening as the ridge axis shifts eastward. The surface ridge will also shift eastward, allowing a very moist airmass to gradually spread into the forecast area from the south and west. PWAT values are forecast to increase to near 2.0 inches by the evening, values which are 2 to 3 standard deviations above normal. Surface dewpoints will creep up during the afternoon and especially evening into the mid-60s to near 70. This will begin to add a few degrees to apparent temperatures. It appears that this will be offset somewhat by lower mixing depths compared with the last couple of days, so high temperatures will likely be a couple of degrees cooler. The net result will be apparent temperatures similar to the last couple of days in the low to mid-90s. At this point it appears we may come up just shy of heat advisory criteria in NY and VT (95F for two consecutive hours). The increased moisture and weaker ridging/subsidence will open the door for isolated to scattered thunderstorm development mainly during the afternoon and evening hours. As the increased moisture and lower heights will be approaching from the west, areas west of the Hudson Valley will see the best instability with SBCAPE increasing to 1000-1500 J/kg. Though forcing for ascent will be weak, we will likely see some scattered showers and thunderstorms developing as we are seeing upstream today from western NY into the central Appalachians, particularly over the higher terrain due to differential heating. Areas from the Hudson Valley eastward have been capped at 20-30 PoPs with precip chances mainly confined to after 20Z due to the weaker instability and more influence of the departing ridge. Weak deep-layer shear (20 kt or less) means that the severe weather potential will be very low, but will also mean that thunderstorms will be slow moving with locally heavy rainfall possible. Isolated minor flooding of poor drainage and urban areas cannot be ruled out mainly west of the Hudson. Midlevel flow will become more zonal Friday night into Saturday. Convection will mainly diminish after sunset with the loss of diurnally driven instability and lack of forcing, but a few lingering showers and thunderstorms will remain possible. On Saturday, slightly better midlevel height falls will spread into the area, and a cold front will approach from the northwest. This increase in forcing for ascent will interact with the anomalously moist airmass (PWAT still around 2.00 inches). Though the surface front will not reach our northwest zones until the afternoon, there is some evidence of convergence along a prefrontal trough sparking convection as early as the mid to late morning hours. The rainfall and cloud cover will likely keep temperatures a bit milder than previous days, but given the high moisture content with dewpoints in the low to mid-70s, some places still may approach heat advisory criteria particularly in the Mid-Hudson Valley which stands the best chance at seeing a period of sunshine in the morning to early afternoon. Despite weak midlevel lapse rates in the tropical environment, the warm and moist boundary layer will contribute to 1- 2 kJ/kg tall and skinny SBCAPE. Deep layer flow will be fairly weak once again but will increase modestly during the afternoon and evening. So once again the severe weather threat will remain low, but the heavy rainfall and flooding threat will be elevated. With deep shear vectors somewhat parallel to the low-level boundaries, there is potential for training convection. Will continue to mention this potential in the HWO and use heavy rainfall wording in the weather grids. Given that the forcing is not overly strong, it`s likely that the whole day won`t be a washout, but coverage is expected to be numerous to widespread in the afternoon and evening. A drier airmass will quickly move into the region Saturday night with trajectories emanating from a 1020 mb high over western Quebec. A few showers may linger early, but clouds and dewpoints will decrease from south to north. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Those looking for a relief from the heat can look forward to the early part of the work week when a more seasonable yet much drier air mass moves into the Northeast. However, by the Wed-Thurs period above normal temperatures and higher humidity levels return ahead of our next chance for showers and thunderstorms. Read on for details. We start the long period off on Sunday as the true cold front in the wake of the showers and storms from Saturday traverses through our southern zones, namely the mid-Hudson Valley and NW CT. The latest guidance continues to hint that there may be enough lingering 700mb moisture in this region to support some leftover early showers. Thus, we continue to show slight chance POPs in southern Dutchess, Ulster and Litchfield counties for early Sunday morning. The CMC-NH is the most robust in this signal while the GFS and ECMWF suggest more in the way of just lingering cloud coverage. Elsewhere across eastern NY and western New England, a dry day is anticipated as a large region of high pressure from the Great Lakes slides southeastward and takes control of the Northeast. While winds should be northerly throughout the region on Sunday, the real air mass change looks to be delayed until midday or even into the afternoon when dew points should finally drop from the upper 50s/low 60s down into the low to mid 50s. This should bring relief to those looking for a day with much less humidity. Given the abundant dry air noted at 700mb in the wake of the true cold front, leftover morning clouds should clear to our south through the day giving us a pleasant and more comfortable day as somewhat breezy northerly winds keeps high temperatures in the mid 70s to near 80. As noted in the previous discussion, PWATS should actually fall to near 0.50 Sunday night and thanks to clear skies in place, radiational cooling should assist most areas cool down into the 50s by 12z Monday. In fact, the Adirondacks should even fall into the 40s. Monday and Tuesday stay dry and seasonable with high temperatures in the low to mid 80s (70s terrain) under sunny skies as the aforementioned large area of high pressure maintains control. An upper level trough crosses through northern New England on Tuesday but the best forcing and moisture looks to remain well to our north and east so continued a dry and sunny forecast. A strengthening ridge in the Great Lakes then heads eastward by Wednesday and as the upper level flow shifts west-northwest, increased warm air advection around the periphery of the ridge should usher in much warmer air into the Northeast. In fact, 850mb isotherms climb to +16C to +17C which should result in surface high temperatures rising back into the mid-upper 80s for the second half of the week. As the ridge axis crosses through our region late Wednesday or Wednesday night, the potential for precipitation increases and we have continued to gradually trend POPs upwards during this period. The best chances for showers/storms still looks to hold off until Thursday as both the ECMWF and GFS both show an amplifying trough from the Great Lakes traveling towards the Northeast with its associated surface low dragging a surface cold front through our area. We thus show widespread chance POPs for showers/thunderstorms on Thursday given the best forcing mechanism will be in place under an increasingly warm and humid air mass. The CMC-NH delays these features until Friday but it seems to be the outlier solution. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Skies will be mainly clear overnight. Patchy light fog may develop after 06z with the best chance for a period of MVFR vsbys or cigs being at GFL or PSF from 07z to 11z. Otherwise skies will remain mainly clear into Friday morning, then some fair weather cu will develop in the afternoon Friday with VFR conditions. Scattered showers and thunderstorms can be expected Friday afternoon west of the Hudson Valley but these are expected to remain west of the TAF sites through the day. Winds will be light and variable tonight, then southerly at 5 to 10 kts on Friday. Outlook... Friday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Saturday: High Operational Impact. Definite SHRA...TSRA. Saturday Night: Moderate Operational Impact. Chance of SHRA...TSRA. Sunday: No Operational Impact. NO SIG WX. Sunday Night: No Operational Impact. NO SIG WX. Monday: No Operational Impact. NO SIG WX. Monday Night: No Operational Impact. NO SIG WX. Tuesday: No Operational Impact. NO SIG WX. && .FIRE WEATHER... Very warm temperatures will continue through Saturday. Humidity levels will gradually increase from south to north on Friday, with RH values bottoming out in the 40 to 55 percent range. Isolated to scattered showers and thunderstorms are expected in the afternoon and evening mainly west of the Hudson Valley. Winds will be light to moderate from the south. Numerous to widespread showers and thunderstorms are expected on Saturday, some of which will result in heavy downpours. A milder and drier airmass will arrive on Sunday, persisting into early in the week. && .HYDROLOGY... An increasingly humid airmass will filter into the area from the south and west on Friday, with PWAT values approaching 2.00 inches. This will allow isolated to scattered showers and thunderstorms to develop in the afternoon and evening mainly west of the Hudson Valley. Storm motions will be slow, so any thunderstorms will result in heavy downpours. Isolated urban and poor drainage flooding cannot be ruled out. On Saturday, a cold front will interact with the anomalously moist airmass, resulting in numerous to widespread showers and thunderstorms from the late morning into the evening. There is potential for multiple rounds of slow-moving convection and training which could result in urban and poor drainage flooding and isolated flash flooding. A limiting factor is that the region has been drier than normal over the past week. A period of mainly dry weather is expected Sunday into early next week. && .ALY WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. MA...None. VT...None. && $$ SYNOPSIS...Thompson NEAR TERM...MSE/BGM/Thompson/Wasula SHORT TERM...Thompson LONG TERM...Speciale AVIATION...Cebulko/MSE FIRE WEATHER...Thompson HYDROLOGY...Thompson
Area Forecast Discussion
National Weather Service La Crosse WI
1057 PM CDT Thu Jul 4 2019 .SHORT TERM...(Tonight through Friday Night) Issued at 133 PM CDT Thu Jul 4 2019 GOES water vapor imagery and RAP 500mb analysis showing a weak mid- level shortwave trough rotating through eastern MN. So far, convection has been somewhat limited with this feature. Latest CAMs very consistent in forming scattered showers and thunderstorms along and ahead of this feature -moving through the area this evening and exiting east by midnight. So, will the fireworks be a washout for tonight? Appears most susceptible area will be along/east of the Mississippi River according to CAMs consensus. There will also be a marginal risk of strong to severe storms as there is plenty of cape (3500-4800J/kg 0-3km mucape), but shear is lacking for organization. Could see some isolated dime to quarter size hail along with potentially damaging microburst. Otherwise, lightning and heavy downpours would be the main impacts. Southwesterly aloft continues Friday, bringing another packet of weakening PV-advection and MCV into the area by late in the afternoon into Friday evening. This will likely trigger additional scattered showers and thunderstorms during peak heating with pv forcing possibly continuing the convection into the overnight hours. Otherwise, plan on highs Friday in the 80s with overnight lows in the 60s. .LONG TERM...(Saturday through Thursday) Issued at 133 PM CDT Thu Jul 4 2019 Slightly drier/cooler air filters into the area for Saturday with highs in the upper 70s/lower 80s and dewpoints in the mid 50s to lower 60s. The NAM has some morning convection but then drying out for the afternoon. However, the GFS and ECMWF linger convection through the entire day. Hopefully, the NAM turns out to be correct as we could use some drying out. Upper level ridge amplifies over the central conus and builds east into the Upper Mississippi River Valley Sunday into Monday. But, as it builds in, there are indications of a weak trough rounding the ridge and producing a few showers and storms -with southern MN/northeast IA/far southwest WI most susceptible. Otherwise, pleasant temperatures and dewpoints are expected. Highs both days look to be in the upper 70s to lower 80s with dewpoints in the 50s/60s. Upper level ridging shifts east Tuesday with a significant trough and surface cold front pushing through Tuesday night into Wednesday. This will likely stir up more showers and storms for the area. Temperatures are expected to be right around seasonable norms. Ridge rebuilds over the area Thursday for some drying, or that is decreasing rain activity. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1055 PM CDT Thu Jul 4 2019 Main concern for tonight will be any potential for fog and/or low cigs. Model guidance is starting to latch onto some low stratus just starting to develop over northern WI and wants to expand this low stratus southward overnight. This would lend itself to the potential for IFR or perhaps LIFR cigs arriving at LSE and RST late tonight, then likely scattering out sometime mid-morning on Friday. Confidence remains low in this potential, but a low stratus does seem more plausible than fog development given there will be a steady breeze just above the surface overnight. Guidance has been slowing down the arrival of the next round of showers and storms for Friday. It was looking like a disturbance aloft would move in towards afternoon, but now early evening is looking more likely for showers and storms popping up in the area. Doesn`t look like anything too widespread, probably widely scattered convection like we`ve seen the past few days. Will continue with just VCSH for now given it would most likely occur towards the end of the TAF period with the usual timing/location uncertainties. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...DAS LONG TERM...DAS AVIATION...Kurz
Area Forecast Discussion
National Weather Service Duluth MN
707 PM CDT Thu Jul 4 2019 .UPDATE... Issued at 706 PM CDT Thu Jul 4 2019 Updated for the 00Z aviation discussion. && .SHORT TERM...(This evening through Friday) Issued at 250 PM CDT Thu Jul 4 2019 An MCV is pinwheeling northward as it exits central Minnesota and is interacting with a quasi-stationary front. So far, rainfall rates have been very heavy with an inch or so in 30 minutes being the norm under the heavier showers. For this reason and for the potential for training storms, opted to issue a flash flood watch for portions of NE MN and NW WI. Mean flow profile is weak, but progressive enough to keep the storms moving. The MCV does slow down this storm movement and even temporarily reverses their flow. While this occurs, training is likely and will greatly increase the flash flood potential. PWATs are quite high near 1.7" and ML CAPE per the SPC RAP is hovering around 1500 J/kg. All good ingredients for heavy rainfall. So far, severe potential has been limited by the shear, but shear is expected to increase through the afternoon especially over NW WI, so that could make things interesting. Storms are expected to dissipate this evening as the MCV moves eastward leaving what should be a window for fireworks for the majority of the forecast area. With the stationary front in the area, there is likely to be more upper level features cross to amplify the baroclinic zone sparking off more MCS`s. So expect more of the same heading into Friday. Timing and placement still uncertain. .LONG TERM...(Friday night through Thursday) Issued at 250 PM CDT Thu Jul 4 2019 Dry and less humid through the weekend with high pressure under control. Shower and thunderstorm chances return for Monday through Wednesday. A ridge will build across the Northern Plains at the beginning of the extended and gradually flatten out and slide eastward through the weekend. There is some discrepancy between the ECMWF/GEM/NAM and GFS latest guidance for Saturday. The GFS has some precipitation chances due to a decaying convective complex sliding in from the Northern Plains. This will be worth watching, but anticipate a dry forecast per the ECMWF/GEM and NAM. Expect northeast winds to accelerate at the western end of Lake Superior, which could bring a high risk for rip currents on Saturday. Winds at 850 hPa will generally be out of the north, which will usher in a drier and less humid airmass. These winds will be all over the place on Sunday as the ridge axis slides overhead. Early next week the ridge will slide into the central and eastern Great Lakes. On the western side of the ridge flow will become southerly, which will advect humid air back into the region. To the west a trough will dig into the Pacific Northwest. This feature will gradually slide eastward and bring increasing chances of showers and thunderstorms Monday through Wednesday. The best chance for precipitation at this point in time is on Tuesday with the trough over the Northern Plains and there is signal for some stronger and potentially severe storms. There is sufficient instability, shear and lift from the cold front associated with the trough. Still too early to get into the specifics as later guidance may slow down or speed up this waves progression into the area. Precipitation chances will decrease on Wednesday as the trough exits. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 706 PM CDT Thu Jul 4 2019 An area of showers and thunderstorms over the Arrowhead of MN and northwest WI is slowly moving east away from the terminals as of issuance time. KHYR has some showers but VFR conditions, with all the other terminals with VFR as well. Expect all sites to be VFR for several hours, but the rainfall in the last 24 hours is likely to produce fog at KHYR and KDLH, and perhaps also KBRD and KHIB. For now only have fog mentioned at KDLH in the 09z-12z time range. KHYR likely to drop to IFR in visibilities and ceilings for several hours between 06z and 14z. After 14z all sites should be VFR. I expect some chances for showers/thunderstorms to skim by the southern terminals beginning around 15z, but confidence on these is fairly low and have included only some VCSH groups for now. && .MARINE... Issued at 250 PM CDT Thu Jul 4 2019 Main concern this afternoon into this evening is scattered thunderstorm activity. Sustained winds will generally remain at 5 knots or less away from thunderstorm activity. If a thunderstorm passes by gusts up to 35 knots or higher along with small hail are possible. This activity should diminish this evening as the cold front slides through. Dense fog along the nearshore waters is possible late tonight into early Friday due to clearing skies and light winds. Any dense fog should lift by mid Friday morning as the mixed layer grows and winds pick up. Still expect winds generally at 5 knots or less on Friday. && .PRELIMINARY POINT TEMPS/POPS... DLH 62 78 57 71 / 60 30 10 10 INL 56 79 51 77 / 0 0 0 0 BRD 65 79 59 77 / 20 40 10 10 HYR 64 82 57 77 / 70 40 20 10 ASX 62 79 55 70 / 70 20 20 10 && .DLH WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. LS...None. && $$ UPDATE...LE SHORT TERM...Wolfe LONG TERM...WL AVIATION...LE MARINE...JJM
Area Forecast Discussion
National Weather Service Goodland KS
526 PM MDT Thu Jul 4 2019 .SHORT TERM...(This evening through Friday night) Issued at 122 PM MDT Thu Jul 4 2019 Latest satellite and upper air analysis show two areas of cloud cover under southwest flow downstream of a long wave trough over the Great Basin. At the surface a cold front extended southeast over South Dakota to Southeastern Wyoming. To the south a surface trough was in place over Eastern Colorado where there was also a surface low. The cloud cover has been lingering longer than expected over the Tri- State Area. Latest data has prolonged the cloud cover into the mid afternoon before ending. The isentropic lift responsible for the cloud cover may persist well into the afternoon before ending, which may cause the cloud cover to linger longer still. The longer the cloud cover lasts into the afternoon, the lower the chances of severe weather will be. This has been reflected in the increasing ML CINh of the RAP this morning. During the late afternoon an upper level short wave trough will move east toward the forecast area and over the surface trough. The surface trough should serve as a focus for storm development, with storms slowly increasing in coverage as they move northeast. Latest near term data indicates the storms should not move into the forecast area until after 6 PM MT. The latest HRRR runs and its derivatives all show storms not moving into the forecast area until 7 or 8 PM MT. If storms do move in, the best chance will be Yuma, Dundy, and Cheyenne County KS, with storm chances increasing to the north. The threats with these storms will be hail up to golf ball size, wind gusts up to 70 MPH, and flash flooding. The intensity of the storms will increase to the north in NE and WY. Given the DCAPE values of 1500-2500 j/kg over much of the forecast area during the evening, am thinking severe wind gusts will be the greater threat. The peak time for storm activity will be after 7 PM MT. The later into the evening the storms move into the forecast area, the less likely they will be severe. However even strong storms will be dangerous enough to cause damage or injury given all the outdoor activities ongoing this evening. Thunderstorm activity should move northeast of the forecast area around 4 AM CT if not before. Even though the near term models all show storm activity mainly over the north 1/3 to 1/4 of the forecast area, there is concern that the nose of the LLJ over the central part of the forecast area may also serve as a source for storm development this evening. As such have extended the chances for storms further south than what the guidance indicates. Behind the storm activity a cold front will move into the forecast area and slow down. Behind the front low clouds and possibly fog will occur. Even though fog has occurred the last two nights, with the air mass change am not confident enough at this time to put fog in the forecast given the shallow nature of the saturated layer at the surface. Friday the cold front will stall. By mid afternoon the front will be over the southeast quadrant of the forecast area, and remain there into the evening. (Models are in much better agreement with this today than yesterday). There will be quite a bit of cloud cover over the forecast area behind the front. However along and ahead of the front the ground should heat up by the afternoon. Meanwhile an upper level short wave trough will move through during the afternoon. Lift will increase along the front during the afternoon. Am expecting storm coverage to slowly build through the afternoon along and east of the front as a result. Prior to the storms merging into clusters, there is a concern for tornado development along the front during the latter half of the afternoon. Low level helicity will increase during the latter half of the afternoon along the front, and storms will be moving parallel to the front. This will allow storms plenty of time to ingest that helicity to produce tornadoes. During the evening this threat goes away as storms merge together. Threats with the storms will be tornadoes, hail up to hen egg size, severe wind gusts and flash flooding. Confidence for severe weather occurring is moderate, with confidence for tornadoes occurring between low and moderate. The threat for flash flooding will mainly be during the night. Friday evening the storm activity will continue to increase over the eastern part of the forecast area. These storms will gradually shift east as the front is pushed south. There is a concern for flash flooding occurring east of Highway 25 where storm activity will have been ongoing for a few hours with slow storm movement. Meanwhile another upper level short wave trough will move into the forecast area from the west. This will provide a second round of rainfall that will continue to move across the forecast area Saturday. On a side note, the location of the front and thus the severe weather will greatly depend on where the front ends up after the storm activity today. .LONG TERM...(Saturday through Thursday) Issued at 101 PM MDT Thu Jul 4 2019 Saturday, the tri-state area will be impacted by another shortwave, bringing potential severe weather conditions once again to the Tri- State area. With several days of persistent rain, a corridor of maximized low-level moisture, moderate instability, and steep mid- level lapse rates, we are looking at, first and foremost, the potential for flooding highlights. That said, there will be additional threats including large hail and severe winds. Timing for convection will be later in the day after peak afternoon heating through the evening. Sunday through Thursday, we see the chance of showers and storms each afternoon and evening. This is a typical summer pattern for the High Plains. At this time, severe weather is not expected, but this could easily change in the next couple of model runs. Several surface disturbances will move across the area, creating the needed forcing to generate afternoon showers and storms. Location of development will be dependent on surface boundaries throughout each day, and at this time, there is still quite some variability in the models as to where storms will set up, so decided to go with the national blend for pops in the extended. As for temperatures, we will see daily highs start to rise starting Saturday afternoon in the low to mid 80s, becoming mostly mid 80s by Sunday afternoon, then upper 80s by Monday, and staying in the low 90s Tuesday through Thursday. Overnight Saturday lows will stay around climate averages in the mid 50s to mid 60s through Monday night. Afterward we will see a slight rise in lows from the upper 50s to upper 60s Tuesday night through Thursday night. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 515 PM MDT Thu Jul 4 2019 Thunderstorms will move out of northeast Colorado and into northwest Kansas/southwest Nebraska tonight. Greatest coverage will be in southwest Nebraska, with storms arriving later this evening. May see brief strong wind gusts with this activity at KMCK. Less confident that storms will impact KGLD. Overnight, fog will be possible. Models have not done very well the past couple of nights with the extent of the fog coverage, and with a an upslope low level wind will go with persistence and include a mention of fog at both terminals. Visibility may go below a mile at times. For Friday afternoon, best chances for thunderstorms will probably remain south of both terminals. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...JTL LONG TERM...EV AVIATION...024
Area Forecast Discussion
National Weather Service North Platte NE
641 PM CDT Thu Jul 4 2019 .SHORT TERM...(This evening through Friday night) Issued at 340 PM CDT Thu Jul 4 2019 The primary forecast challenge through Friday night deals with thunderstorms and severe potential. A surface boundary / cool front bisecting the Sandhills should drop south tonight, which will be the focus for the storms. The atmosphere is primed for large hail, strong winds, and torrential rainfall. This evening and tonight... Convective initiation is underway across northwest Nebraska (Sheridan Co) as of 20z. A few thundershowers are also pulsing up and down along the differential heating boundary, roughly aligned with I-80, caused by a stubborn stratus deck over far SW Neb. Expect an increase in activity through the evening in the panhandle as CIN continues to erode and upper air support arrives in the form of an H5-7 shortwave. Severe indices suggest the potential for large hail, damaging winds, very heavy rain, and possibly a tornado. The 19z LBF RAOB shows a cap remaining around H7, while SPC mesoanalysis suggests it`s quickly eroding (also shown by the showers). Instability is ample (MUCAPE 2000-3000j/kg) due to mid/upper 60s dew points and lifted index around -5. CAPE in the -10 to -30C hail growth zone is also rather fat. Deep layer shear has increased to around 40 kts in western Neb and around 30 kts central Neb, which is sufficient for organized and sustained convection. Short-term model guidance is in agreement with bringing the LLJ nose right into southwest Neb, which should increase low level shear. Current southeast surface winds are creating a veering profile and are not forecast to change much tonight. Thinking the greatest hail and tornado threat will be west of Hwy 61, where convective mode is more likely to be supercellular. Around 06z, storms should grow more upscale around the Hwy 83 corridor as they become more elevated and the wind profile becomes more unidirectional. Forecast soundings maintain plenty of DCAPE (1000+ j/kg) while the storms become clusters or a QLCS, adding to the damaging wind threat. Included heavy rain wording to the entire CWA as PWATs are well above climo, moisture transport vectors indicate a large fetch of moisture streaming up the Plains, and previous nights` rainfall totals have exceeded one inch. The greatest thunder coverage, and subsequent severe threat, should be out of the CWA by 12z. Generally followed a blend of the HRRR and NAMnest for storm timing. Friday and Friday night... Continued thunder mention as the region sits in easterly/upslope flow in the post fropa environment. Sufficient instability remains with the help of cooler temps aloft/steep lapse rates and continued moisture advection in the low levels. Deep layer shear is also supportive of severe potential. Concerns include effects from tonight`s convection, location of outflow boundaries, the lack of an LLJ, and overall coverage (CAMs not as bullish). Cooled max temps slightly to account for mixed cloudiness, northeast flow at H85, and potential storms. Forecast highs range from upper 70s along the Pine Ridge to mid 80s far southwest. .LONG TERM...(Saturday through Thursday) Issued at 340 PM CDT Thu Jul 4 2019 The synoptic pattern into early next week suggests continued periodic thunderstorm chances and seasonable temperatures for western Nebraska. The area sits on the periphery of the Western US trough and southern Plains high, a favored area for storm tracks and in an environment supportive of strong convection. Various surface boundaries (quasi-stationary or warm front Sunday and cool front Tuesday) will add forcing and lift. Temperature-wise, highs should stick to the lower 80s through the weekend, then warm early next week under WAA and southerly flow at H85. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 634 PM CDT Thu Jul 4 2019 Scattered thunderstorms should develop across north central and southwest Nebraska, most thunderstorm development will be late tonight, however there are a few isolated thunderstorms across Cherry County this evening, but should remain south of KVTN. Lower ceilings are expected to move in tomorrow morning into the day tomorrow with MVFR conditions at times. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Snively LONG TERM...Snively AVIATION...Gomez
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
944 PM CDT Thu Jul 4 2019 .UPDATE... Issued at 941 PM CDT Thu Jul 4 2019 Scattered showers and thunderstorms have dissipated across the area, and expect mainly dry conditions the rest of the evening into the overnight hours. The RAP continues to show some weak low level moisture convergence ahead of mid level vort max that will move into central Missouri late tonight. This supports the CAMS reflectivity which brings scattered showers and thunderstorms back into central Missouri toward daybreak. Britt && .SHORT TERM... (Through Late Friday Night) Issued at 314 PM CDT Thu Jul 4 2019 Scattered SHRA/TSRA developed today within an unstable environment due to the influence of an MCV as well as a weak PV anomaly which was moving slowly across the region. Storm coverage is expected to remain scattered through the late afternoon and early evening hours. Storm coverage should decrease with the loss of daytime heating, but numerous outflow boundaries noted on radar could still serve as the focus for isolated SHRA/TSRA to percolate into the early overnight hours. BUFKIT soundings from the RAP, HRRR, and NAM all depicted a stout inversion tonight in east central and southeast MO, and winds are expected to be light across most of the CWA. This combination means that it may be difficult for residual smoke from Independence Day fireworks to dissipate this evening, especially over east central and southeast MO into southwestern IL. Patchy smoke has been added to the gridded database to reflect this scenario. After a relative lull in convection overnight, the combination of diurnal instability along with what appears to be another weak PV anomaly (or possibly an MCV, depending on upstream convective trends overnight) will bring increasing SHRA/TSRA chances to the region on Friday. Models show slightly more 0-6km shear (perhaps as much as 20 kts) across the western and northwestern CWA on Friday afternoon compared to Thursday, which means that a few stronger storms cannot be ruled out. However, as SPC noted in their SWODY2 discussion, the placement of mesoscale boundaries will also be important for determining the severe weather risk on Friday. Seasonable temperatures will persist through tomorrow night with highs in the upper 80s to lower 90s and overnight lows in the lower 70s. Kanofsky .LONG TERM... (Saturday through Next Thursday) Issued at 314 PM CDT Thu Jul 4 2019 Upper level ridging that has generally been more dominant over the southeastern U.S. will begin to build westward into the weekend. As this transition occurs, weak southwesterly flow over the central U.S. temporarily turns zonal. This keeps us in the warm and humid sector through at least Saturday. Beyond Saturday, there are questions regarding the progress and position of a cold front that sags in from the north. What remains evident in the large scale pattern is that weak upper flow persists, as smaller 500mb vort features pass around the northern periphery of the upper ridge. Ample moisture and peak daytime surface instability suggest that the theme for scattered pulse type convection will continue Saturday. One of the 500mb features that is more clearly depicted by medium range guidance passes southeast over eastern Missouri sometime late Saturday morning into early Saturday afternoon. Should this pan out, it will likely play a role in overall storm coverage with greatest potential over southeast Missouri and southern Illinois. Otherwise, expect mainly diurnally driven convection that weakens through the evening. Meanwhile, surface high pressure over the Saskatchewan and Manitoba is projected to build southeast into the Great Lakes Region through the later portion of the weekend. This aids the southward progress of a weak surface front late Saturday and early Sunday. The main impact this could have is to provide temporary relief from heat and humidity for some. I believe the main challenge presented here is the strength and position of the surface high, which could determine precipitation potential Sunday afternoon, as another upper shortwave presses in from the northwest. Given these questions, chance PoPs seem fitting at least west of the Mississippi River. Conditions look relatively quieter heading into next week as we remain tethered to the western edge of the surface high. The high continues to slowly build in over the Ohio Valley as upper ridging is slightly offset to the west and strengthens. Isolated to scattered diurnal storms will be possible most days, but widespread rainfall seems unlikely. Maples && .AVIATION... (For the 00z TAFs through 00z Friday Evening) Issued at 628 PM CDT Thu Jul 4 2019 Scattered showers and thunderstorms near the St. Louis area terminals are expected to dissipate early this evening. Then lowered visibilities in smoke from fireworks are expected at St. Louis area airports between 02-06Z given light winds and what has happened in recent years. Then mainly dry weather is expected overnight with some patchy fog. Additional scattered showers and thunderstorms are expected during the afternoon on Friday with some lowered ceilings/visibilites. SPECIFICS FOR KSTL: There remains the threat for showers and thunderstorms at the terminal through 01Z before they dissipate by mid evening. Then lowered visibilities in smoke is expected between 02-06Z from fireworks given light winds and what has happened in recent years. Then mainly dry and VFR conditions are expected through midday Friday before the threat for additional scattered storms move in during the afternoon. Britt && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
758 PM EDT Thu Jul 4 2019 .SHORT TERM...(This evening through Friday) Issued at 449 PM EDT THU JUL 4 2019 WV imagery and RAP analysis indicated a trough into the northern Rockies and a a ridge over the southeast CONUS resulting in wsw mid/upper level flow from the northern Plains to the northern Great Lakes. An MCV into nw WI supported shra/tsra from east central MN into western Upper Michigan. At the surface, a weak trough/front extended from northern Lake Superior to southern MN. Southerly low level flow has brought dewpoints into the mid 60 to around 70. Although MLCAPE values to around 1500 J/Kg and 0-6km shear values to 30 knots were marginal for severe storms, PWAT values into the 1.5- 2.0 inch range support the potential for heavy rain. Tonight, expect the shra/tsra to slowly spread eastward through the west half of Upper Michigan, per radar/satellite trends and CAMs. Although a strong to severe storms with local high wind gusts cannot be ruled out, the main hazard will continue to be heavy rain. over the western third of Upper Michigan. Expect the shra/tsra coverage/intensity to diminish toward late evening as it moves through central Upper Michigan but could still disrupt evening outdoor/fireworks plans. Sct shra/tsra moving into the east after midnight will diminish with mainly just light showers by daybreak. Abundant moisture and light winds will favor areas of fog, locally dense overnight. Friday, expect dry conditions through the morning as weak high pressure and some drying move in with light northern winds. The potential for another shrtwv moving out of the plains along with daytime heating could generate sct shra/tsra inland over the the south where MLCAPE values to near 1k J/Kg are possible away from the stable nrly flow off of Lake Superior. .LONG TERM...(Friday night through Thursday) Issued at 302 PM EDT THU JUL 4 2019 Overall, a fairly quiet extended forecast with cooler and drier weather expected through the weekend. A few of the medium-range models are showing some hints of convection trying developing on Saturday afternoon as a shortwave tracks east across the area. However, with high pressure settling in and much drier air moving into the region the chances for showers/storms seems unlikely so did keep a dry forecast going. Otherwise, this weekend continues to look like a beautiful weekend! Did make a few adjustments to dew points to lower RHs as high pressure and ample sunshine will allow for decent afternoon mixing and drier air mixing down to the surface. Early to the middle of next week, high pressure will track east of the region and return flow will put us back under the warmth and increasing humidity. Towards mid-week, chances for showers and storms will increase as the main ridge axis aloft shifts east and ample moisture continues to stream northward ahead of a shortwave tracking across the Northern Plains into the Upper Great Lakes. Medium-range guidance is already a bit slower with the arrival of this precipitation; therefore, would not be surprised if chances end up getting pushed back further given the dry air expected to be in place ahead of this next shortwave. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 752 PM EDT THU JUL 4 2019 Showers and thunderstorms are slowly rolling across the west half of Upper Michigan this evening, with all three terminals directly impacted. Although the activity is winding down near KIWD, additional storm chances will persist for another few hours before moving out of the area entirely. KSAW should see direct impacts within the next couple of hours, with KCMX remaining on the periphery of where lightning has been occurring. Once this activity does move out of the Upper Peninsula, fog/LL stratus will take hold as copious amounts of LL moisture linger through the remainder of the overnight period, coupled with light to calm winds. VFR conditions will reappear after sunrise tomorrow at all three terminals, with generally northerly winds taking over. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 449 PM EDT THU JUL 4 2019 Under a weak pres gradient, winds thru the weekend will mostly be 15kt or less. Strongest winds will probably occur Fri night into Sat as high pres builds se toward the northern Great Lakes. There may be some gusts in excess of 20kt during that time. Patchy to areas of fog could still linger across portions of Lake Superior, especially the e half. Until the cold front passes late tonight into Fri morning, this fog will likely linger, moving around with the prevailing winds. Any lingering fog should clear out by late Fri/Fri night. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Ritzman AVIATION...lg MARINE...JLB
Area Forecast Discussion
National Weather Service Pocatello ID
216 PM MDT Thu Jul 4 2019 .SHORT TERM...Tonight through Sat Night. HRRR continues to show more thunderstorm activity than the NAM and GFS, so have biased PoPs higher for areas from Pocatello southward. It all appears to be over around midnight as the area slides eastward during the evening, with thunderstorms ending in the Pocatello area around 2100 tonight. In the central Idaho mountains, thunderstorms will clear out even earlier. Nocturnal thunderstorms should continue in the highlands near the ID-WY border. The trough triggering this activity will have cleared out by Fri morning, and the thunderstorm activity on Fri will be limited to the ID-MT border region, possibly as far south as Challis and Mackay. On Sat, another trough will move through and trigger another round of showers and thunderstorms with the focus on the western portions of the forecast area, the central Idaho mountains and south central Idaho. Except for ridges, wind should stay below 20 mph sustained with a warming and drying trend that accelerates on Sat. Messick .LONG TERM...Sunday through Thursday. A low pressure system moves over our area later Sunday into Monday morning. Expect Isolated to Scattered showers and thunderstorms for mainly our northern areas in the Central mountains and along the Montana Divide. This convective activity may extend south into the Eastern Highlands along the Northern Wyoming border as well. Look for breezy to moderate winds mainly Sunday and Monday each afternoon. Southwest flow sets up over the area Tuesday through the end of the week with high pressure building in overall. There has been a lot of inconsistency in the long term. Previous model runs showed strong high pressure over the area by the end of the period. This is more uncertain now. Expect above normal temperatures Sunday before dropping back below normal Monday, Tuesday and, to a lesser degree, Wednesday. By Thursday temperatures should be near normal to above normal again. Wyatt && .AVIATION...A low pressure system is moving the area currently impacting mainly our northwest(mostly the Central mountains), our southern, and southeast areas (Southern Highlands, Southeast Highlands and the Wasatch mountains). Expect VCTS thunderstorms for KSUN and KBYI and, to a lesser degree, for KPIH. Models are now holding off thunderstorms and precipitation, in general, for KIDA and KDIJ. Expect breezy winds for TAF sites until early evening. Also look for gusty winds of 25 to 30 mph in around thunderstorms. Wyatt && .FIRE WEATHER...While a piece of a trough over the Pacific Northwest is currently moving through and triggering showers and thunderstorms tonight, low pressure will continue over the Pacific northwest. There is just enough of a wind shift around that low to produce some drier westerly flow for Fri, but then another low comes into phase with this weakened low and re-inforces it. This will return the southwest flow and will bring back warmer and more unstable air on Sat. So on Fri, the thunderstorms should be limited and mostly along the border with MT, but on Sat will return to a greater coverage area, mostly in the central Idaho mountains and the south central portions of Idaho. Strong warming and drying develops on Sat with the warmer air, which continues into Sun. On Mon, the low pressure trough to the west of the Gem State starts moving through eastern Idaho for more showers and thunderstorms and a drop in temperature/rise in humidity. However, it does not get replaced and high pressure over the southern states expands northward to dominate southern Idaho weather, this will be the first extended warm period of the summer, eventually pushing Snake River plain highs into the 90s and humidity crashing in valley locations to below 15 percent on a regular basis. There are some winds beginning Sun afternoon before the Mon low arrives, until it departs far enough to the east on Mon night. Messick && .PIH WATCHES/WARNINGS/ADVISORIES... None. && $$