Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/19/17

Area Forecast Discussion
National Weather Service Amarillo TX
636 PM CDT Mon Sep 18 2017 .AVIATION... For the 00Z TAFs: VFR conditions will prevail throughout the valid TAF period. There are signs in the model output for low level wind sheer around 1000 feet sometime around 06Z and 12Z between the three terminals as a jet around 45 knots looks possible. I may add this with an amendment after some newer model data comes in, but I wanted to make note of that now for planning purposes. Its mainly speeds shear as not much turning is evident from the surface to the low level jet. Otherwise, it will be breezy tomorrow afternoon into early evening. Guerrero && .PREV DISCUSSION... /Issued 231 PM CDT Mon Sep 18 2017/ DISCUSSION... The cloudy start to the day has slowed our warming potential. Most of the area has struggles to reach the 80 degree mark. This will also hurt our storm chances given that we will struggle to break the cap. The HRRR is still holding onto an isolated storm across the eastern zones this evening. Have gone with a 10 POP to cover this isolated chance but confidence is pretty low. On Tuesday, we will see the typical Panhandle winds return to the area. Southwestern winds will quickly be on the rise through the morning hours as a lee side low moves across eastern Colorado. Winds will top our in the 15 to 25 mph range with briefly higher gusts. Given that our high temperatures are expected to be in the 90s could result in fire weather concerns (see Fire Weather section below). Late Tuesday night into Wednesday morning, a cold front is expected to drop into the Panhandles. Northerly winds and a cooler airmass over the area will help to keep out high temperatures near normal across the northern zones. Thursday will see the upper flow become southwesterly as a low moves southward from the Pacific Northwest. This pattern is expected to persist through the weekend. This pattern will also result in multiple chance for precipitation as embedded shortwaves within the upper flow moves over the area. There will be enough shear to draw the eye on the potential for organized convection. Will continue to monitor as we move closer to the weekend. FIRE WEATHER... Thanks to slightly cooler high temperatures today our relative humidities are not expected to drop below 20 percent today. On Tuesday, we will see much warmer temperatures (daily highs will run roughly 10 to 20 degrees above normal). These much warmer temperatures will combine with dew points dropping into the 30s and 40s to push our minimum relative humidities into the 12 to 20 percent range for the better portion of the Panhandles. Our winds speeds will also be on the rise throughout the day on Tuesday as a lee side low moves across eastern Colorado. The tightening surface pressure gradient will result in 20 ft winds in the 20 to 25 mph sustained. These conditions will result in meteorological critical fire weather conditions from the far western Oklahoma Panhandle and the northwestern Texas Panhandle as well as elevated fire weather conditions for all but the southeastern Texas Panhandle. With that being said, much of this same area saw wetting rains last night and early this morning. Wet fuels will help to mitigate our fire weather expectations. A Fire Danger Statement may be warranted for the far northwestern part of the area for initial attack activity given how much drying will occur tomorrow. Cooler temperatures and lower wind speeds will prohibit elevated fire weather conditions on Wednesday. && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 99/99
Area Forecast Discussion
National Weather Service Burlington VT
723 PM EDT Mon Sep 18 2017 .SYNOPSIS... High pressure will dominate our weather for the week. The high pressure will also keep Jose well south of New England, so all that we will see is an increase in clouds and chances for showers across central and southern Vermont late Tuesday and Wednesday. The rest of the region will remain dry this week. The high pressure will also keep temperatures above normal. && .NEAR TERM /THROUGH TUESDAY NIGHT/... As of 505 PM EDT Monday...Modest update for late afternoon/early evening to increase pops across the southern Champlain Valley and the western Adirondacks per greater coverage of shower activity than prior indications. Could be a stray rumble of thunder, but lapse rates aloft aren`t all that impressive - limiting overall updraft strength. A few of the showers could put down brief heavier downpours through sunset as evidenced by prior MRMS estimates of between 0.50 and 1.50 inches in southwestern Rutland County in the Lake St. Catherine/Wells/Poultney areas. The rest of the forecast remains on track as of 500 pm so no other adjustments needed at this point. Enjoy your evening! Prior discussion... Forecast in decent shape for the afternoon. Did make some minor adjustments based on latest radar trends for placement of the initial small showers that have bubbled up over the higher terrain. HRRR still seems the best of the convective models, so followed it`s lead. Given the moisture depth is not all that much and the amount of mid level dry air in place, the isolated showers we get will remain across the higher terrain and will not last long nor bring any significant precipitation. And 0% chance of thunder. Temperatures across the region are at or above previously forecast highs, so did adjust upward a couple of degrees. It appears the smoke layer aloft is just a bit thinner than it was yesterday, so we are getting just a little bit more insolation to warm things up. Well, at least that is my theory. Winds remain light, though there is a tendancy for them to turn southeast across Vermont in response to Jose well to the south. Overnight: expecting another quiet night, with areas of fog once again developing, especially in the more normal fog areas. Lows again well above normal, with 50s to lower 60s. Tuesday: Watching for low level moisture from the Atlantic being advected westward into portions of eastern Vermont. More guidance is picking up on this, and given the flow around Jose, it does make sense. Thus expecting it to end up being a "murky" looking day for southeast Vermont with low stratus hanging tough, even after the morning fog lifts. The clouds will also have an impact on temperatures, and continued with the idea of only in the lower 70s down around Springfield, while near 80F/low 80s in the Champlain Valley and points westward. Looks like that Atlantic moisture gets deep enough for some light rain showers by afternoon. Liked how the NAM and NAM3km are handling it, so used a model blend to drive the hourly PoP/weather evoluton. Tuesday night: 12z guidance didn`t suggest anything much different than what we previously had. Looking at 35-50% chance of light rain for roughly a St J to Rutland line and points south. That should be the farthest northwest any rain shield from Jose should make it. Even then, the rain won`t be heavy. Maybe upwards of 1/4" of rain. Otherwise we are too far away to see any strong winds. Once again, overnight lows will be above normal with 50s to lower 60s. && .SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/... As of 330 PM EDT Monday...Models continue to show the ridge building over the region Wednesday-Wednesday night as Jose begins a more easterly motion. This will keep most of the BTV forecast area rain free. The exception may be far southern Vermont where scattered rain showers related to Jose may persist. Will hold on to a 30 pop to cover the low chance. Temps should be closer but still slightly above normal in the lower to mid 70s. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 330 PM EDT Monday...Forecast looks pretty quiet across the region in the long term, with the ridge holding strong. Have kept the forecast dry throughout the time period. The warm temperatures will also continue with the area seeing a slow warming trend. && .AVIATION /00Z MONDAY THROUGH SATURDAY/... Through 00Z Tuesday...VFR through most of the period with a few exceptions. 1) Brief MVFR conds possible in lingering shower activity across the Adirondacks through 02Z. 2) Patchy br/fg and IFR/LIFR likely at KMPV/KSLK after 05Z, possible at KPBG/KMSS though confidence lower at these latter terminals. 3) BKN/OVC MVFR marine stratus may encroach northward into eastern/southern VT after 06Z. Confidence low/moderate on how far north and west this progresses overnight, but models do show a pronounced southeasterly surge of 15-20 kts above 800ft tonight so time will tell. If this surge is more pronounced than currently forecast, then br/fg/ifr threat at KMPV would be lower later tonight. After 12Z Tuesday...mainly VFR under light/modest east/southeasterly flow from 5-10 kts, though again, if marine stratus advances further northwest than currently forecast, lower MVFR cigs could linger at southern/eastern terminals such as KMPV/KVSF etc. Outlook... Tuesday Night: VFR. Slight Chance SHRA. Wednesday: VFR. Slight Chance SHRA. Wednesday Night: VFR. NO SIG WX. Thursday: VFR. NO SIG WX. Thursday Night: VFR. NO SIG WX. Friday: VFR. NO SIG WX. Friday Night: VFR. NO SIG WX. Saturday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Nash NEAR TERM...JMG/Nash SHORT TERM...NRR LONG TERM...NRR AVIATION...JMG
Area Forecast Discussion
National Weather Service Hastings NE
655 PM CDT Mon Sep 18 2017 .SHORT TERM...(This evening through Tuesday) Issued at 255 PM CDT Mon Sep 18 2017 Stratus/low clouds have been slow to exit today, holding temperatures down with most readings in the 70s across south central Nebraska, with a few 80s in north central Kansas. The pattern aloft depicted subtle southwest flow ahead of an upper trough moving into British Columbia, while at the surface, a low pressure trough was deepening along the front range of the Rockies into the high plains region. As we head into the evening, lingering low clouds will lift out with steady southerly low level flow forecast through the overnight hours. Models indicate the potential for isolated convection overnight on the nose of the lowlevel jet which will be oriented to our southeast, so have kept the dry forecast going for our area with the better chances for this remaining to our east/south. Have some concern for the development of fog given the wet ground and high dewpoints, and light southeast wind component. SREF probs and NAM visibilities both suggest the northern half of our cwa may be more susceptible for fog and have included patchy fog in the forecast. Tuesday will be warm and windy in a tight pressure gradient/deep mixing. The upper low in the Pacific Northwest translates into Alberta with the upper trough digging into the northern and central Rockies. The associated surface trough pushes east of the high plains into western Nebraska and Kansas in the afternoon. Dewpoints mix out, along and west of the boundary to the 30s/40s, with low relative humidity values forecast below 20 percent for Furnas, Phillips and Rooks Counties. The combination of low relative humidity values, south wind gusts over 30 mph and favorable fuel status across north central Kansas and southwest portions of south central Nebraska have prompted a Fire Weather Watch for Tuesday afternoon. Outside the Fire Weather Watch area, near critical fire weather conditions are expected for locations west of a line from Lexington, Nebraska to Smith Center, Kansas. Temperatures will be noticeably warmer, reaching the upper 80s to mid 90s for highs. .LONG TERM...(Tuesday night through Monday) Issued at 255 PM CDT Mon Sep 18 2017 After a brief cooling behind a cold front Wednesday, warm weather will settle in for the remainder of the workweek, followed by a cool and wet weekend. A cold front pushes southeast Tuesday night as the lead upper low tracks across Canada and this boundary looks to move through dry. High pressure builds south behind the front Wednesday and temperatures will drop back to near 80F for highs in the slightly cooler air. The surface ridge axis departs to the east Wednesday night with return flow of southerly winds and warmer air returning to the plains, ahead of an upper trough digging along the west coast. The pattern will become highly amplified by the end of the workweek with the plains in southerly flow aloft in between the intermountain/western trough and an upper ridge from the gulf to the Ohio Valley/Great lakes region. Thursday and Friday are looking warm and windy with highs well above normal in the upper 80s/low 90s (normal highs average in the upper 70s this time of year), with winds steady/gusty from the south. Chances for rain ramp up over the weekend as the upper trough axis edges farther east into the Rockies with the associated frontal boundary aligning across the plains over the weekend and the boundary will be the focus for showers and thunderstorms for several days. Rainfall with this system looks to be fairly widespread and amounts may potentially top one and two inches by the end of the weekend. The frontal boundary is forecast to slowly move southeast Sunday night into Monday, with rain chances beginning to taper off in our northwest zones, but continue in the southeast. Look for temperatures to trend cooler over the weekend and into next week, dropping below normal by Monday. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday) Issued at 642 PM CDT Mon Sep 18 2017 Main impacts to aviation through this forecast period will be the potential for fog Tuesday morning and breezy south winds Tuesday afternoon. Light southeasterly winds will be favorable for a radiation fog to develop during the early morning hours. HRRR and RAP are coming into line with the SREF for the most dense fog to be north and east of the terminals. That said, I maintained a TEMPO group of IFR visibility for KGRI because I am concerned that recent rainfall may enhance the fog a bit into central Nebraska. Nevertheless, fog potential will decrease as you move farther westward, so I just 4SM visibility at EAR. Whatever fog does develop will dissipate quickly as a stiff south to southeasterly wind develops by late morning. Wind gusts during the afternoon will likely range from 22 to 28kts. && .GID WATCHES/WARNINGS/ADVISORIES... NE...Fire Weather Watch from Tuesday afternoon through Tuesday evening for NEZ082. KS...Fire Weather Watch from Tuesday afternoon through Tuesday evening for KSZ005-017. && $$ SHORT TERM...Fay LONG TERM...Fay AVIATION...Mangels
Area Forecast Discussion
National Weather Service Wilmington NC
951 PM EDT Mon Sep 18 2017 .SYNOPSIS... Hurricane Jose will continue to lift off to the north leaving dry and warm weather across the area through much of the week. An increased rip current risk will linger along some beaches due to continued swells. Hurricane Maria is expected to track to the north offshore of the Carolinas during the middle of next week but uncertainty remains. Maria is a powerful hurricane, bringing increasingly strong rip currents and dangerous marine conditions to the area late this week through at least early next week. && .NEAR TERM /THROUGH TUESDAY/... As of 950 PM Monday...Hurricane Jose is essentially stationary about 230 miles east of Hatteras Island. Aside from a light northerly breeze and some cirrus streaming in from the east there are no impacts on our weather from Jose. Temperatures have fallen rather quickly this evening as some spots inland have already decoupled from the boundary layer with calm winds noted. Radiational cooling should drop temperatures into the mid 60s for most locations overnight, with a little ground fog possible in spots as dewpoints recover. The biggest forecast challenge remains the potential for another late night low stratus event to surge southward out of eastern North Carolina. The 12 and 18Z runs of the GFS were quite bullish with the potential, however the NAM and ECMWF were not as they had low level winds backed just a little more westerly which kept the low clouds north and east of ILM. The last couple of HRRR runs do bring some low stratus into SE North Carolina near sunrise. Although I earlier believed we might get through the night without low clouds, after noting the current observation up at Greenville, NC I am beginning to question the premise of a clear late night/early morning for areas east of Elizabethtown, Whiteville, and Oak Island. Other than some increased cloud cover around daybreak in the Cape Fear area, no significant changes were made to the forecast with this evening update. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...Quiet conditions will continue for the most part through the period. The mid level pattern will feature a weak westerly flow that morphs into a decent trough late Wednesday into early Thursday. The GFS and ECMWF are painting a few showers in the area late Wednesday into early Thursday while some of the other guidance is void of this activity. I did add a slight chance of showers to address. No significant changes to temperature guidance or forecast. && .LONG TERM /THURSDAY THROUGH MONDAY/... As of 1200 PM Monday...Persistent high pressure will be reinforced from the north Fri and Sat. Did include a small risk for a shower or thunderstorm Thu, before high pressure strengthens across the area. Did include a small risk for an afternoon shower or thunderstorm along the seabreeze Sat and Sun. Monday`s forecast will hinge to a large degree on the track and strength of powerful Hurricane Maria and we will be watching the tropics especially closely. Tropical cyclone Jose or its remnants will be virtually stalled SE of New England late in the week and may actually begin to drift S Fri and through the weekend. Hurricane Maria is expected to be a powerful hurricane as she approaches during the weekend. Her forerunner swell energy will begin to be felt on the Carolina beaches late week which will increase the breaking wave heights and rip current risk. A high risk for rip currents is likely this weekend and early next week. Much too early to have any confidence in a track forecast for Maria as she approaches the southeast coast. Some of the models continue to show interaction between Maria and Jose early next week and Jose may play a part in the path Maria ultimately takes as she gains latitude and approaches the U.S. east coast. Highs will be in the mid and upper 80s Thu and Fri and lower to mid 80s thereafter. Lows will be mainly in the 60s. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 00Z...VFR conditions are expected up through 0800Z. Patchy ground fog could develop in spots between 08-12Z, but this potential appears low in all areas but the LBT airport where low-level winds should be lightest and will offer the best potential for visibility restrictions. Models also show another night of low stratus developing across far-eastern North Carolina, but unlike in at least the last three nights this stratus cloud cover is not expected to make it into ILM, instead remaining just north and east of the area. Extended Outlook...Mainly VFR conditions through the period are expected with the exception of a few hours of early morning low clouds or fog most mornings through the period. The highest risk of IFR conditions will be in the 0900-1200Z timeframe each morning. && .MARINE... NEAR TERM /THROUGH TUESDAY/... As of 950 PM Monday...4-6 foot seas are just barely hanging onto the Cape Fear area waters. Even out at the Frying Pan Shoals buoy the latest wave height was only 5.5 feet. Given the direction of the swell it`s very likely larger seas continue on the other side of the shoals, and the advisory will remain up for now. Hurricane Jose is essentially stationary about 230 miles east of Hatteras. Shallow water on Capes Hatteras and Lookout are blocking a good deal of the swell energy from reaching our area, and shadowing from Cape Fear is further protecting the South Carolina coastal waters this evening. Steady but diminishing northerly winds are expected overnight with few additional chances necessary to the forecast. SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 300 PM Monday...A weak pressure pattern will continue through the period across the coastal waters. Wind speeds will be ten knots or less through the period. Wind direction will be primarily from the southwest but a weak surface trough passing through early Thursday will push winds to more of a westerly direction at that time. Significant seas will be 2-3 feet. LONG TERM /THURSDAY THROUGH SATURDAY/... As of 1200 PM Monday...The risk for Small Craft Advisory seas is increasing this weekend. Weak high pressure will prevail through the period but will become better established from the north late week. Long period swell, the forerunners of powerful Hurricane Maria, will begin to reach our waters during this time. The swell energy looks to become significant Fri and Sat. The swell direction will be from the SE. Guidance is showing periods of around 15 seconds at Frying Pan Shoals with wave heights increasing from 4 to 5 ft Fri to 6 to 7 ft Sat. The swell will further increase Sun and Mon which will result in higher wave heights. && .TIDES/COASTAL FLOODING... As of 300 PM Monday...The lower Cape Fear will see high astro tides again with tonight`s high tide cycle this evening, and a `coastal flood advisory` was needed for water levels almost a half foot above the advisory threshold for downtown Wilmington. Minor flooding will occur between 8pm-11pm tonight downtown, and more coastal flood advisories are likely according to tidal predictions through at least the first day of Fall, and September 22nd at 2002Z this year Autumnal Equinox occurs. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...Coastal Flood Advisory until 11 PM EDT this evening for NCZ107. MARINE...Small Craft Advisory for hazardous seas until 8 AM EDT Tuesday for AMZ250-252. && $$ SYNOPSIS...SHK NEAR TERM...TRA SHORT TERM...SHK LONG TERM...RJD AVIATION...TRA TIDES/COASTAL FLOODING...MJC
National Weather Service Jackson KY
1045 PM EDT Mon Sep 18 2017 .UPDATE... Issued at 1045 PM EDT MON SEP 18 2017 Freshened up the near term grids to make sure they were on track with the latest observations. Several locations in the far eastern portion of the CWA have dropped near to or even below the forecasted lows for overnight. This led to some adjustments in the overnight lows and diurnal trends to better accommodate the current trends. Also, the HWO and TAFs are giving dense fog wording, but noticed it was not reflected in the grids. Went ahead and added dense fog after 6Z, ranging from patchy to areas. All changes have been published and sent to NDFD/web. A new forecast package was sent out to reflect these changes and change to overnight wording. UPDATE Issued at 755 PM EDT MON SEP 18 2017 Forecast is on track so far this evening. Loaded in the latest observations to make sure the near term grids were on track with current conditions. Still a few isolated showers ongoing across the far western portion of the CWA. Once these have tapered off, will update the grids to remove the pre-first period rain mention and sent out a new forecast package. All changes have been published and sent to NDFD/web. && .SHORT TERM...(This evening through Tuesday night) Issued at 435 PM EDT MON SEP 18 2017 20z sfc analysis shows weak high pressure in place over eastern Kentucky though it is not effective in suppressing a few showers now popping up over western parts of the Cumberland Valley. On satellite, most of the area is seeing just small patches of cu, but through the breadth of the Cumberland Valley, where the showers are active, the clouds are more extensive and robust. Plenty of sunshine for most of the area have sent temperatures up into the lower 80s. Meanwhile, dewpoints are holding in the low to mid 60s with the winds still light and variable. The models are in fairly good agreement with the recent changes in the mid and upper air patterns through the short term portion of the forecast. They all now are a bit more hearty with the energy that initially drifts through the weakening ridge this evening and then even more so on Tuesday afternoon and evening. This latter batch will lower heights and pool like a small trough between periods of still rather weak ridging into Wednesday morning. Given this agreement have favored a blended model solution along with a good portion of specifics from the higher resolution HRRR and NAM12 and a healthy dose of persistence - especially tonight and early Tuesday morning. Sensible weather will feature some widely scattered showers through early evening - mainly over the western parts of the CWA. a stray thunderstorm cannot be ruled out, as well. Otherwise, it will be more of the same with clearing skies this evening and cooling conditions leading to areas of fog - locally dense in the river valleys for Tuesday morning. Look for the fog to dissipate a bit quicker Tuesday morning as clouds move in from the west ahead of a weak front. This will likely result in showers and thunderstorms developing by early afternoon favoring the western portion of the forecast area. The convection will die out in the evening setting the stage for more fog development that night into Wednesday morning - though limited by more clouds being around through the night. The CONSShort and ShortBlend were used as the starting point of all the grids. Did make some adjustments to the temperature ones each night based on terrain in anticipation of small to moderate ridge/valley splits. As for PoPs, did tweak them for the diurnal cycle peaking late afternoon and diminishing after sunset. .LONG TERM...(Wednesday through Monday) Issued at 306 PM EDT MON SEP 18 2017 An upper level ridge will amplify over the Ohio Valley through the period continuing the unseasonably warm weather pattern for our area. A weak upper trough trapped between Hurricane Jose and the building ridge over the Mississippi Valley will cause the potential for a few showers and storms Wednesday and Thursday. That potential shifts to our southwest and withers as the upper trough dissolves and surface high pressure builds southward ensuring a dry weekend for our region. Temperatures are expected to consistently top out in the low to mid 80s each day through the period. Overnight lows are forecast in the low 60s, then dropping into the upper 50s over the weekend as drier air filters in. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 801 PM EDT MON SEP 18 2017 After another day and evening of VFR conditions, fog is expected again tonight. Development will commence after 03z, starting in the valleys, not likely impacting TAFS until after 06z. Fog should be similar to the past several nights and be confined mainly to the valleys, but still creep up into a couple of the airport sites for a time, most likely near dawn. Have used a tempo in a few of the TAFs for this concern. VFR conditions will then re-establish themselves for the first part of the day tomorrow after the fog dissipates in the morning. For the afternoon, scattered showers and thunderstorms will move into the region from the west, along with generally SCT CIGS between 3 and 4k ft. Included VCTS in TAF sites between 18 and 20Z, though exact timing/location and impacts of these storms is still low confidence. Light winds are expected through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JMW SHORT TERM...GREIF LONG TERM...ABE AVIATION...GREIF/JMW
Area Forecast Discussion
National Weather Service North Platte NE
652 PM CDT Mon Sep 18 2017 .SYNOPSIS... Issued at 309 PM CDT Mon Sep 18 2017 H5 analysis from this morning had a tandem of closed lows over southern Canada. The first was over northern Ontario and the second was off the coast of central British Columbia. Across the lower 48, with the exception of the Pacific Northwest, a low amplitude pattern was noted. Shortwave energy tracked through the central plains overnight and led to a broad area of showers and thunderstorms across the region. After beginning the day with broad coverage of low cloudiness, skies have gradually cleared this afternoon. Readings as of mid afternoon across western and north central Nebraska were generally in the 70s. && .SHORT TERM...(This evening through Tuesday) Issued at 309 PM CDT Mon Sep 18 2017 In the short term, fog potential tonight, followed by fire weather concerns Tuesday afternoon are the main forecast concerns. For tonight: A trough of low pressure will deepen across eastern Wyoming increasing southerly and southeasterly winds across western and north central Nebraska. With low level cloudiness just off to the east and light serly winds tonight, a decent setup exists for the development of fog/stratus, especially over the southern half of the forecast area. This notion is supported by the latest NAM12 and 4KM NAM solns which push moisture west into central and swrn Nebraska overnight. Did go ahead and insert some patchy fog for the eastern sandhills and southwestern Nebraska. I did not push the fog mention to areas of fog as the numerical guidance and HRRR soln didn`t support that just yet. The surface trough will slide east into the panhandle and northwestern sandhills Tuesday morning. With surface heating, the fog and stratus will push east and dissipate by noontime. By afternoon, low pressure will begin to deepen over nern Colorado, producing southwesterly winds and forcing a dry line into portions of southwestern Nebraska. As of 21z Tuesday, the dryline, will lie down roughly along highway 25 from Sutherland to Palisade. West of this feature, temps will reach the lower to middle 90s with minimum RH`s falling to 10 to 15 percent. East of the dryline, RH`s will fall off to 15 to 25 percent across the eastern panhandle and western sandhills. Winds on Tuesday will be strongest east of the panhandle where a nice pressure gradient will lead to breezy conditions across most of the forecast area. Across the panhandle and western sandhills, winds will be lighter as they will be under the influence of a pre frontal trough of low pressure. With winds of 10 to 20 MPH and some gusts approaching 25 MPH and minimum RH`s of around 15 percent, decided to hoist a red flag warning for zone 210 which will run from noon to 6 PM MDT. .LONG TERM...(Tuesday night through Monday) Issued at 309 PM CDT Mon Sep 18 2017 Active pattern coming our way as a large upper level trough digs south through the western portions of the United states. Our region will remain on the eastern periphery of the upper trough with southwest flow aloft to dominate through midweek. Then as the trough digs farther south into the southwest Conus, a more south-southwest flow aloft will develop for the last half of the week including the weekend. Still a small chance for thunderstorms Tuesday night across far northern Nebraska along a cold front, but the better focus will remain north in the Dakotas where better dynamics associated with the upper level wave will be located. SPC has shifted the threat for severe mostly out of our area, and agree with the better chances remaining to the north. The cold front will scour out the moisture for Wednesday through Thursday night and expect dry conditions during this time. For Friday into the weekend, rain/thunder chances will increase, as both quality low level moisture and upper level dynamics become favorable for precipitation development. As the flow aloft becomes near meridional, south-southwest aloft, potential for several rounds of showers and thunderstorms training over the same locations through the weekend. WPC indicates the potential for up to 1.25 inches across the panhandle, with near 4 inches possible farther east across northern into central Nebraska. Will have to monitor for potential heavy rain this weekend. Highs will be warm through the end of the week, and then cool off for the weekend as clouds and the threat for rain increase. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 624 PM CDT Mon Sep 18 2017 Latest satellite imagery shows a swath of high clouds moving eastward across western NEB, otherwise fair conditions exist. Primary concerns this TAF package are fog/stratus and LLWS conditions. Mostly clear skies will prevail through the evening. Stratus and fog become a concern early morning tomorrow and current thinking is for stratus/fog to develop westward into north central NEB and parts of southwest NEB. Current thinking is KLBF terminal more likely to see impacts from fog/stratus than KVTN thus its inclusion in the TAF. Thereafter conditions are anticipated to improve mid-late morning. Otherwise, LLWS conditions associated with a low-level jet is a concern as it develops across far western NEB into SD tonight. The area of concern for LLWS conditions is over northwest NEB and northern NEB given forecast soundings and guidance. Elsewhere, LLWS conditions are expected to be marginal or not be present thus no mention in the KLBF TAF at this time, but will monitor and may need to update the TAF if conditions or guidance warrant. && .LBF WATCHES/WARNINGS/ADVISORIES... Red Flag Warning from noon to 6 PM MDT Tuesday for NEZ210. && $$ SYNOPSIS...Buttler SHORT TERM...Buttler LONG TERM...Taylor AVIATION...ET
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
929 PM CDT Mon Sep 18 2017 .UPDATE... Minor update to extend the isolated thunderstorm mention to encompass the far eastern zones through the remainder of the evening hours. Current small but occasionally fairly robust convective cores have continued to persist and even expand in coverage this evening. They may continue right into the eastern Rolling Plains. Given the trends, have expanded the mentionable PoPs eastward this evening. More recent iterations of the RAP, HRRR and TTU-WRF also indicate potential isolated activity redeveloping further west over the South Plains tonight. Given modest moistening seen upstream in the water vapor imagery, decent residual elevated instability that will be in place and a developing southerly LLJ, additional (albeit likely isolated at best) convection appears possible late tonight into the early morning hours Tuesday. Given this we have also added a minimal thunder mention for much of the CWA in the 06-12Z time-frame. No other significant adjustments were made to the forecast at this time. && .PREV DISCUSSION... /issued 632 PM CDT Mon Sep 18 2017/ AVIATION... VFR conditions are expected through Tuesday. Isolated showers with a bit thunder should remain south of the terminals this evening. Without the cool post-convective air mass ala last night, restrictions to visibility and/or ceilings are unlikely. PREV DISCUSSION... /issued 320 PM CDT Mon Sep 18 2017/ DISCUSSION... Two weak areas of surface convergence, one along the northern borders of Garza to Stonewall counties and the other across southeastern Briscoe county, and a dryline currently in eastern NM will be the main areas of focus for potential convective development later this afternoon and evening. The timing of initiation should line up with a jet maxima pushing northeastward out of Chihuahua. Currently the FA is located along the exit region of the jet maxima which is aiding in some subsidence. Storm chances should decrease after sunset as the jet pushes east of the FA. Some storms could become severe and produce damaging winds up to 70 mph and hail up to one inch. Rain chances will be low tomorrow into Thursday and Friday as flow remains mostly zonal aloft. By late weak an upper low will dig southward across the western CONUS placing the region back under southwesterly flow aloft. A lee trough will allow surface winds to be out of the southeast transporting Gulf moisture into the FA ahead of the approaching upper low. Rain chances will increase from the west as the low moves slowly towards the FA by Friday into Saturday. The 12z model runs have slowed down the eastward progression of the upper low which would delay the timing of lift moving into the region. Previously models were showing decent lift pushing into the FA by late Friday into Saturday but are now holding off until late Saturday/early Sunday. Given the slower model guidance pops will continue to be kept below the likely category with higher chances favoring our northwestern zones. Chances will increase as a front pushes southward into West Texas early next week. As ample moisture will be in place and the low will be slow moving heavy rain could very well be possible, but it is still too early to tell. Temps, however, should be cooler and more fall like as the front moves through and cloud cover remains. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 23/07
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CDT Mon Sep 18 2017 .DISCUSSION... Isolated late afternoon showers over the extreme north diminished early this evening. An old and weakening gust front was observed just south of OHX at 745pm, and had actually helped to cool temperatures off a bit faster than the normal nocturnal trend early this evening over parts of the extreme north. However, expect temperatures over all of the Mid-State to stabilize mainly in the upper 60s to lower 70s by midnight, and then slide on down to the lower and middle 60s by dawn. Even though latest HRRR doesn`t give us much prospect for showers for the remainder of the night, can`t rule out some re-development late tonight, per previous AFD. So, will leave pops and wx as they are. No need for any changes to the forecast package at this time. && .AVIATION... 00Z TAF DISCUSSION. BNA/MQY/CKV/CSV...Surface and upper ridge have shifted some to the east, allowing an upper trough to amplify and push across Middle Tennessee tomorrow. This will produce a few more clouds and also bring scattered POP`s to the mid state beginning late tonight through much of tomorrow. Look for fog to develop once again overnight, with forecast VSBY`s based largely on last night`s observations. && .PRELIMINARY POINT TEMPS/POPS... Nashville 67 87 67 89 68 / 20 40 10 30 10 Clarksville 66 86 66 87 67 / 40 40 10 30 10 Crossville 59 80 61 81 62 / 10 40 10 40 10 Columbia 64 86 65 87 66 / 10 40 10 40 10 Lawrenceburg 64 85 65 86 66 / 10 40 10 30 10 Waverly 66 85 67 87 67 / 40 50 10 30 10 && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......19 AVIATION........08
Area Forecast Discussion
National Weather Service Topeka KS
626 PM CDT Mon Sep 18 2017 ...AVIATION UPDATE... .SHORT TERM...(This evening through Tuesday) Issued at 316 PM CDT Mon Sep 18 2017 Clouds are breaking out from west to east across the area as a leading shortwave trof makes it exit eastward. Another weaker wave is moving over western Kansas at this hour, and its axis will likely be just to our east after midnight. A few models suggesting an isolated shower or storm possible with this wave, although the HRRR keeps much of it over central and southern Kansas. Warmer temperatures already seen mixing down over western and south central Kansas, and will be the main story for tomorrow as those temps move eastward. Turning of the LLJ winds over this front may generate a few storms toward morning over the eastern counties, but again chances are low and have only carried a low PoP at this time for that area. Biggest change will be the temperatures tomorrow as the western areas hit middle 90s with dewpoints in the 60s, and even in the east we rise to upper 80s with dewpoints near 70, so it will feel quite warm and muggy tomorrow as heat indicies near upper 90s to 100. One factor that may help will be increasing winds, as breezy southwest winds of 15 to 20 with gusts to 30 develop tomorrow. Lows tonight fall into the mid 60s. .LONG TERM...(Tuesday night through Monday) Issued at 316 PM CDT Mon Sep 18 2017 Wednesday time frame a weak boundary (hard to call it a cold front) will likely push into the area during the day as an upper level shortwave pivots through the Northern Plains around the main low in Western Canada. Therefore, forcing for ascent resides mainly to the north of the area. Also, per forecast soundings, quality of moisture is likely not great in western portions of the forecast area, but with higher dewpoints pooling along the boundary as it slowly pushes southeast may come into play by late in the day into early evening increasing MLCAPE values based on some guidance up above 4,000 J/kg. Lack of deep layer shear along with weak mid level lapse rates may be an inhibiting factor into severe potential and coverage. So, probably just isolated to scattered storms may form but with increasing isentropic lift into the overnight time frame, associated with a weak LLJ, will keep some showers going for the overnight period focused mainly into the northern MO region extending back into very eastern portions of the forecast area. Quiet weather should prevail into the day Thursday until Saturday late morning/afternoon time frame as a deep western CONUS trough becomes more established and slowly shifts east drawing up gulf moisture along a quasi-stationary/cold boundary on the eastern flank of the trough. Dynamics and Kinematic forcing don`t look impressive over the area, so any hazardous weather potential seems low, but could be a wetter weekend overall. Temps for the period will be upper 80s and low 90s for the week before cooling back into the lower 80s over the weekend in association with cloud cover and precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 626 PM CDT Mon Sep 18 2017 There is some potential for elevated storms overnight, but models seem to focus the better isentropic lift and moisture advection to the southwest of the terminals. So chances do not look to be good enough to include a mention in the forecast just yet. Chances for LLWS also look to be weakening as the magnitude of the low level jet is progged to be weaker than before. Opted to maintain a mention at TOP where winds may be backed more and at MHK where low level winds could still be a little stronger. Outside of any thunderstorms impacting the terminals, conditions should be VFR through the period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...67 LONG TERM...Drake AVIATION...Wolters