Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/20/18

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
535 PM MDT Sun Aug 19 2018 .AVIATION... 00Z TAF CYCLE Upper high center to move from AZ over NM durng the next 24 hrs. Sfc high pressure to continue building strongly swd into the eastern NM plains and along the east slopes of the central mt chain thru 20/12Z, with lcl MVFR cigs obscuring terrain possible from KRTN to KLVS and K0E0 aft 20/06Z. A gusty east wind into the RGV at KABQ and KSAF is expected to develop, with gusts from 25kt to 35kt. A few showers and tstms to sag swd from ne NM at 19/23Z into east central and se NM, an isold strong to severe storm with hail and wnd gusts to 50kt possible before 20/03Z. In addition, lcl MVFR vsbys due to HZ/FU will be found from the RGV westward to the AZ border. HRRR smoke model indicates vsbys will improve in the RGV once the east wind develops, but may linger in the San Juan/Animas Valleys thru 20/12Z. && .PREV DISCUSSION...330 PM MDT Sun Aug 19 2018... .SYNOPSIS... A moist back door front will dive through the eastern plains and into the central valley with a gusty east wind below canyons tonight. The strongest wind will be below Tijeras Canyon where gusts may reach 45 mph after midnight. The front will trigger scattered to isolated showers and thunderstorms along and especially east of the central mountain chain overnight. Although the front will improve low level moisture some, very dry air aloft will limit shower and thunderstorm development to the mountains on Monday. High temperatures will also trend downward a few to several degrees across central and eastern areas on Monday. A more traditional monsoon flow will develop Tuesday through the end of the week as the subtropical high pressure system builds east of New Mexico steering a persistent plume of subtropical moisture over the state from the south and southwest. This will result in daily rounds of scattered to at times numerous showers and thunderstorms over western, northern and central areas. High temperatures will vary from near normal to around 6 degrees above normal. && .DISCUSSION... Thunderstorm outflows from convection on the eastern plains should give the gusty east canyon wind a little extra push tonight. Models are forecasting borderline advisory speeds at KABQ overnight, but these should be a little stronger due to the thunderstorm outflows. Very dry air aloft that moved over the state from the northwest in the wake of yesterday`s upper level trough will remain in place through Monday. This will limit thunderstorm development again. The subtropical high will move over south central parts of the state from the west on Monday. Meanwhile an upper level low pressure system will move into the Pacific northwest, and this will begin to draw some subtropical moisture northward over southern NM under the ridge. Thus, the best coverage for showers and thunderstorms on Monday will be over the southern high terrain, where scattered to isolated activity is expected. Depending on the model, the subtropical high is expected to center somewhere around Texas or the lower Mississippi River Valley Tuesday through the end of the week. There will be a marked increase in thunderstorm coverage and rainfall intensity starting Tuesday afternoon. A more active period for storms may be Thursday as an upper level trough crossing the northern and central Rockies interacts with this moisture. 44 && .FIRE WEATHER... A backdoor cold front will move across the northeast plains this afternoon and continue to the west and southwest tonight. The front will interact with sufficient moisture and surface heating to generate isolated showers and thunderstorms across the northeast plains and adjacent highlands this afternoon and evening. Stronger storms will be capable of producing large hail and damaging wind gusts. The backdoor front will produce isolated to scattered showers and thunderstorms across the eastern plains tonight. As the front moves across the central mountains, east to southeast gap winds in the Middle Rio Grande Valley will range between 25 to 40 mph with gusts of 35 to 50 mph late this evening and overnight. Relative humidity recovery will be good to excellent across most of the area tonight, except to the west of the Continental Divide, where fair recovery is expected. As the backdoor cold front stalls just to the west of the Continental Divide Monday, increasing low level moisture behind the front will result in minimum relative humidity from 25 to 40 percent east of the central mountains and between 15 and 25 percent from the central mountains to the Continental Divide. Relative humidity will fall below 15 percent across the Northwest Plateau and Northwest Highlands Monday afternoon. High pressure aloft will drift eastward over NM Monday, and light winds aloft will contribute to surface winds less than 15 mph across the entire region. Ventilation rates Monday will be good across the Northwest Plateau and poor to fair across the rest of the region. As the upper level high shifts eastward into West TX Tuesday, subtropical moisture will increase slightly across western and northern NM. Scattered showers and thunderstorms will develop Tuesday afternoon and evening across portions of western and northern NM. Slow storm motion Tuesday afternoon and evening will create the potential for flash flooding. Minimum relative humidity Tuesday will be above 20 percent across the entire region, and winds will be 5 to 15 mph across western and central NM and 15 to 20 mph across eastern NM. Ventilation rates will be good to excellent across much of the region Tuesday, except for areas of fair ventilation across portions of western and south central NM. As the upper high progresses further east Wednesday through next weekend, a south to southwest flow aloft over NM will continue to transport subtropical moisture northward across NM. Daily rounds of showers and thunderstorms can be expected through this period with the greatest chances across western and northern NM. 28 && .ABQ WATCHES/WARNINGS/ADVISORIES... Wind Advisory from midnight tonight to 6 AM MDT Monday for the following zones... NMZ519. && $$
Area Forecast Discussion
National Weather Service Denver/Boulder CO
813 PM MDT Sun Aug 19 2018 .UPDATE... Issued at 804 PM MDT Sun Aug 19 2018 Precip has ended across the entire area as upper level low is over the central Plains. Main change for the rest of tonight into Mon will be adding smoke across the plains which will eventually spread into the higher terrain as well. Visibilities across ern WY have been in the 3-5 mile range which have spread across the border into nrn CO. HRRR Smoke model shows areas of smoke spreading across most of the plains overnight and into the higher terrain on Mon. && .SHORT TERM...(This evening through Monday) Issued at 227 PM MDT Sun Aug 19 2018 Water vapor imagery showing upper low over central portions of Nebraska this afternoon with some energy still rotating around the upper low over northeast colorado. This has resulted in scattered showers and a few thunderstorms to break out over the plains. As the low continues to push away from Colorado, showers will diminish by early evening along with loss of daytime heating. With clearing skies expected tonight and under cooler airmass, overnight lows will drop into the 40s over a good portion of the plains tonight. For Monday, the high pressure ridge will build back into Colorado with a drying and stable airmass. No storms expected with some warming of temperatures in the afternoon. .LONG TERM...(Monday night through Sunday) Issued at 317 PM MDT Sun Aug 19 2018 Models show northwesterly flow aloft continuing Monday night. The upper ridge axis slides back eastward into the CWA Tuesday continuing through Wednesday night. The flow aloft stays west- southwesterly through those periods. There is some synoptic scale energy over the CWA Tuesday afternoon and evening. The low level winds are expected to be east and southeasterly Monday night and Tuesday into Tuesday evening. Maybe weak drainage later Tuesday night. Southeasterlies dominate on Wednesday with drainage Wednesday night. For moisture, precipitable water values gradually increase on Tuesday and stay in the 0.75 to 1.30 inch range into Wednesday evening. Moisture decreases overnight Wednesday. There is quite a bit of mid and upper level moisture over the CWA from Tuesday morning into mid day Wednesday. There is a tad of CAPE over the southwestern CWA Monday evening. There is decent CAPE progged late day Tuesday for the mountains, foothills and Palmer ridge. There is little to none over the plains. On Wednesday and Wednesday evening, CAPE increases a bit more and covers all of the CWA except the eastern border. The QPF fields get pretty excited Tuesday night with decent amounts of measurable rainfall over much of the CWA. The current going pops are pretty high already. Will keep or go with 30-60%s mid day Tuesday keep through Tuesday night. Mainly just "scattered" pops for the mountains late day Wednesday. For temperatures, Tuesday`s highs are 0-2 C cooler than Monday`s. Wednesday`s highs come up about 2-5 C from Tuesday`s highs. For the later days, Thursday through Sunday, there is a weak upper trough to move across Colorado on Thursday and Thursday evening. For Friday and Saturday, flat upper ridging is in place. On Sunday, the upper ridge center migrates eastward into the southeastern United State, with a fetch of south and southwesterly air aloft for the CWA. Moisture is fair on Thursday then again on Sunday. The best pops will be over the mountains. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 804 PM MDT Sun Aug 19 2018 Winds have diminished and may switch to a light north to northwest component in the next few hours. After midnight they will become light southwest. Areas of smoke may affect the area after midnight into Mon morning. There is some potential for visbilities of 3 to 5 miles late tonight into Mon. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...RPK SHORT TERM...Entrekin LONG TERM...RJK AVIATION...RPK
Area Forecast Discussion
National Weather Service Columbia SC
1039 PM EDT Sun Aug 19 2018 .SYNOPSIS... Surface high pressure in the Atlantic will extend westward along the Gulf Coast through Monday. North of this ridge troughing will be in the forecast area. The pattern supports scattered to numerous showers and thunderstorms with near normal temperatures through Tuesday. Drier air and a reduced chance of rain expected mid week with lower humidity and near to slightly below normal temperatures. && .NEAR TERM /UNTIL 7 AM MONDAY MORNING/... Weak upper troughiness over the region with some weak upper impulses moving through early tonight. Surface trough across the western Carolinas. Latest radar indicates litttle activity over our forecast area (FA), with some activity to our north along an apparent weak surface boundary. Latest HRRR still indicates some convection may move into, or develop over, the northern Midlands later tonight presumably due to track of upper impulse and interaction with the surface boundary. So, will leave in chance POPs for that area. && .SHORT TERM /7 AM MONDAY MORNING THROUGH TUESDAY NIGHT/... An upper level trough pushing into the Midwest will suppress high pressure aloft off the Southeast U.S. coast during this time period. Moist southwest flow will be over the region, and a weak shortwave passing north of the area could amplify diurnal convection on Monday evening. As the trough progresses eastward on Tuesday, convergence ahead of a cold front will bring scattered to numerous showers and thunderstorms. The front will also bring increased shear, and there is a marginal risk for isolated severe storms across the Upstate and northern Midlands. Temperatures will be near normal with highs around 90 and lows in the low 70s. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... In the wake of the cold front, Canadian surface high pressure will impact the region through the end of the week. This airmass will bring somewhat cooler and noticeably drier conditions to the Southeast U.S.. Daytime temperatures will be in the mid to upper 80s while overnight lows will be in the 60s. Precipitation chances will be minimal Wednesday through Friday. Onshore flow will return on Saturday and Sunday bringing diurnal convection. && .AVIATION /03Z MONDAY THROUGH FRIDAY/... VFR conditions through 08Z. There is a possibility of stratus redevelopment early Monday morning but confidence is limited with only the NAM showing the stratus while other guidance not indicating cig restrictions. The SREF also keeps IFR/MVFR stratus well west of the TAF sites. May also see MVFR vsbys develop 09Z-13Z given abundant low level moisture and near calm wind. Any early morning restrictions should lift by late morning. High moisture with precipitable water near 2 inches combined with heating and convergence into the weak surface trough supports scattered thunderstorms after 18Z. EXTENDED AVIATION OUTLOOK...Areas of late night and early morning stratus and fog are possible during the outlook period. There will also be a chance of mainly afternoon and evening thunderstorms. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
National Weather Service Eureka CA
239 PM PDT Sun Aug 19 2018 .SYNOPSIS...Hot and dry conditions will continue through Monday, followed by a cooler pattern during the remainder of the week. Otherwise, smokey conditions will persist across much of the region during the work week. && .DISCUSSION...An upper-level trough will move toward Oregon and California tonight with models now coming into better consensus regarding its placement. Cooler temperatures are expected Tuesday as the trough swings through the area. High temperatures across the interior are forecast to be in the mid 80s to low 90s, with seasonable temperatures along the coast. In addition, a slight chance for an isolated thunderstorm exists over northeastern Del Norte county Tuesday afternoon and evening, but the greatest threat should be north and east of the region. Current visible satellite imagery shows smoke and haze impacting much of the region, which supports the inherited Air Quality Advisory in effect for Hoopa, Orleans, Weitchpec, Lewiston, and Trinity Center. Recent HRRR smoke guidance indicates a large area of smoke will spread south from wildfires in British Columbia during the next 24 hours, which could impact northwest California by Monday night. && .AVIATION...As promised stratus made a triumphant return along the coast last night and has been hanging tough much of the morning. As winds and heating have begun to increase early this afternoon clearing has begun at ACV and CEC. Across the interior smoke from area wildfires continue to blanket the region with reduced visibilities, currently UKI is reporting LIFR conditions due to smoke. Expect generally MVFR to IFR visibilities and opaque smoke layers to persist through this taf cycle. As was the case yesterday, by early this evening expect coastal stratus to redevelop along the entire coast bringing IFR to LIFR ceilings and visibilities to ACV and CEC. These conditions will prevail through Monday morning. /WCI && .MARINE...The brisk northerly winds and steep seas will continue to impact the waters through Monday evening. The one exception is the northern inner waters where winds and seas will continue to gradually decline through the afternoon. The southern waters will continue to experience very brisk northerly winds especially near and downwind of Cape Mendocino through tomorrow where occasional gale force gusts are possible. Model guidance continues to show northerly winds decreasing in intensity Monday afternoon and evening which will allow seas to also gradually subside. Light to moderate southerly winds develop along the Mendocino coast by Tuesday morning and across the rest of the waters by Wednesday morning as a low pressure center moves offshore. Winds will become northerly again by mid to late week. /WCI && .FIRE WEATHER...Nocturnal offshore flow is expected to continue through Monday night across interior Del Norte county. Gusts to 25 mph are possible along the ridge tops. Otherwise, hot and dry conditions, with temperatures in the 90s, will continue through Monday. In addition, a small chance for an isolated thunderstorm exists across northeastern Del Norte county Tuesday afternoon, though confidence is low. && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 5 PM PDT this afternoon for PZZ450. Small Craft Advisory until 9 PM PDT Monday for PZZ470-475. Small Craft Advisory until 9 AM PDT Monday for PZZ455. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Glasgow MT
850 PM MDT Sun Aug 19 2018 .DISCUSSION... Evening Update (9pm MDT): Mostly cosmetic changes to the forecast for the evening package. PoP chances were brought down a touch tomorrow as some more uncertainty in exact placement and intensity creeps into even the near term. Winds were also lowered for the overnight as most sites are already light and variable, but the afternoon winds were kept mostly the same. Dramatically dropped MinT for tomorrow morning, especially in the far east, as cloud cover will be minimal and 40s instead of 50s may be likely for many locations east of Glasgow. The rest of the forecast was in good shape. Bigelbach AFTERNOON UPDATE: Northeast Montana will remain on the cool side of the cold front through Tuesday. There is an upper ridge in place now, and a developing trough off the NW Coast. As the trough moves inland, rain showers & thunderstorms will spread over Central Montana. A shower or two may drift into our area on Monday. But most of the storm energy moves into SE MT & Wyoming by Monday evening. Overrunning moisture and a fluctuating frontal boundary may generate local isolated overnight showers through Tuesday. Monday with its cooler air will see temperatures about 10F degrees cooler than normal. Expect around 5F degrees cooler than normal for Tuesday. Wednesday should see near normal temperatures. Smoke: The Experimental HRRR Near Surface Smoke model suggests clearing from the northeast today. Visibility sensors at the airports show improving visibility. We will have smoke of varying intensity until the wildfires are put out, probably from a large wet storm moving over western Canada & the Pac-NW. There is such a storm that is showing up on GFS & ECMWF for early next week. Templer Previous discussion for mid-week and beyond: Expect a broad weak high pressure area at the surface to develop, and east to southeast winds will allow temperatures to gradually increase through mid- week, even with the upper low moving into central Montana. Thursday the upper low will move across northeast Montana, bringing a chance of thunderstorms to our southern zones. Even so, surface moisture is expected to be limited, so little precipitation is anticipated with this. Dry lightning may be a concern, but it is still a little too early to tell for sure. Beyond this, model solutions diverge somewhat, but suggest a weak shortwave moving across the area at some point next weekend, with a stronger system early next week. Even with a few models suggesting this, dramatic changes often occur that far out, so went with the model consensus. Hickford && .AVIATION... Flight Category: VFR to possible MVFR Smoke: There is still a mass of wildfire smoke over much of the state, and over the northeast. Currently conditions are well in VFR for the sites but other smaller airports have been reporting visibility down to near MVFR levels. These conditions are expected to remain generally that way through tomorrow at least, but the nature of the smoke remains quite variable and thus needs close monitoring. Precipitation: A weak disturbance may possibly bring some isolated VCSH activity to the region tomorrow, mostly to the west, which could impact GGW. Otherwise, dry conditions are expected to generally continue for the next several days. Wind: Expect light and variable winds tonight for much of the region, with a strengthening to 5-10 kts tomorrow afternoon out of the northeast. Bigelbach && .GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE. && $$
Area Forecast Discussion
National Weather Service Grand Junction CO
528 PM MDT Sun Aug 19 2018 .SHORT TERM...(Tonight through Monday night) Issued at 354 PM MDT Sun Aug 19 2018 The main weather concern for most people within our CWA through Monday is the smoke which continues to move into our area from wildfires near and far. HRRR model still forecasting an increase of low level smoke into our CWA tonight, especially after midnight and continuing on Monday. A shortwave disturbance in the flow over our area late Monday and Monday night should decrease the amount of low level smoke but will not likely get rid of all of the smoke, especially the higher altitude smoke. That same disturbance will likely produce scattered showers and thunderstorms over northeast UT and northwest CO favoring the mountains. .LONG TERM...(Tuesday through Sunday) Issued at 354 PM MDT Sun Aug 19 2018 The models are showing the upper high center drifting slowly eastward across NM Monday night and Tuesday, and then into TX by early Wednesday. This will result in a southerly flow allowing subtropical moisture to flow northward into our CWA Tuesday and Wednesday for increasing showers and thunderstorms. Models indicate precipitable water values rising to just over an inch in SE UT and into SW CO, which may be a tad conservative. Anyway, we`ll be monitoring the recent burn scars and other flash flood prone areas very closely for any heavy rainfall which may occur on them. And we will be relying on our storm spotters, emergency managers, law enforcement, and others, in addition to the automated rain gauges, to keep us informed with near real-time ground truth information on measured rainfall and any rainfall runoff impacts. The GFS is still indicating a decrease in showers and thunderstorms beginning on Thursday, though the EC is not showing as much of a downturn, as the flow aloft becomes more westerly across our area. Then both models show significantly more drying on Friday under that westerly flow aloft, though there still may be a few late-day high-based thunderstorms over the mountains. Any drying later in the week might be short-lived as the GFS is indicating subtropical moisture spreading back up into our area from the south beginning on Saturday and continuing through the weekend. EC is also showing a return of subtropical moisture, but later in the weekend than the GFS and initially more to the east of our CWA. Both models appear to be quite similar by Sunday with implications of some heavy rain showers within our CWA at least in SW CO and the SE corner of UT. Max temperatures should be near normal throughout our CWA for most of the long term forecast period. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 528 PM MDT Sun Aug 19 2018 VFR conditions will prevail at all TAF sites over the next 24 hours as a strong ridge of high pressure builds to the west. Wind gusts to 25 knots will be possible through 03Z before winds diminish after sunset. Smoke from the numerous ongoing wildfires in the western U.S. will continue to filter into eastern Utah and western Colorado with localized areas of reduced visibility expected. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...JRP LONG TERM...JRP AVIATION...MMS
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
931 PM CDT Sun Aug 19 2018 .UPDATE... Updated for evening discussion. && .DISCUSSION... The last of the evening convection was noted over Webster and Clay counties and may spread into northern Lowndes before dissipating during the next hour or two. Much of the area will remain dry tonight but latest HRRR and other hi-res models still indicate potential storms back over our northwest zones prior to sunrise. Have removed pops the remainder of the night across most of the CWA but wl maintain pops over the Delta region toward morning. Patchy fog will be possible in the southeast along with morning stratus expected across much of the CWA. Temperatures were adjusted in areas that received rain this evening but morning lows were on track for mid 70s at most locations. /22/ Prior discussion below: Tonight: An active period of weather will continue through tomorrow as a closed mid/upper-level low is progged to propagate from the Central Plains into the Midwest by tomorrow evening. This will send an associated surface cold front towards the area with continued showers and thunderstorms along and ahead of the front. Through the rest of today, the greatest thunderstorm coverage continues to remain along the Hwy 84 and I-59 corridors where the greatest destabilization has occurred outside of this morning`s widespread cloud coverage. Latest visible satellite imagery indicates a cumulus field trying to develop in a ring around the dense high clouds left over from the convective complex over the northwest Delta. A few showers have already managed to develop along the western Ashely County line in southeast Arkansas with additional development further south expected. The main uncertainty continues to be convective evolution through the rest of this afternoon into this evening as hi-res CAM guidance continues to struggle on both spatial and temporal scales. The current forecast thinking is for an eventual composite outflow boundary from the southern convection to gradually push north towards the I-20 corridor and initiate additional convection. Additional outflow boundaries and interactions would help foster continued showers and storms further into the heart of the CWA, however this will be conditional as to how much destabilization ends up being realized where cloud cover is slower to dissipate. While a few strong to isolated severe storms with locally damaging winds remain possible, coverage will remain too low to mention in the HWO/graphics. The ongoing area wide limited risk for flash flooding will also be kept as is due to recent heavy rains. By tonight, convection will begin to dissipate with loss of daytime heating, however there`s decent agreement that a dissipating line of showers and storms could enter the Delta late tonight into early tomorrow morning. Monday: The main focus will be the encroaching cold front and associated convection both along and ahead of the front. Showers and thunderstorms are expected to get an early start my mid to late morning, especially along and southeast of the Natchez Trace corridor as daytime heating commences in a moist environment. No severe weather is expected from this early activity, however locally heavy rainfall and isolated flash flooding will remain possible. While timing differences remain, the main focus will be for a broken line of convection to enter the Delta along the cold front during the mid to late afternoon hours and propagate east through the early evening. While mid-level lapse rates remain weak (5.5-6 C/km), increasing tropospheric wind fields will yield upwards of 35-40kts of 0-3km shear which will be juxtaposed with 2500-3500 J/kg of SBCAPE. Mid/upper-level dry air will also be moving in resulting in upwards of 1200 J/kg of DCAPE in area average forecast soundings. As such, have included a limited risk for severe weather in the HWO/graphics with the main threat being damaging wind gusts and hail up to quarter size. Given the aforementioned parameters, an eventual upgrade to a slight risk cannot be entirely ruled out if confidence in coverage and convective evolution increases. /TW/ Monday night through Saturday: Anomalous mid level cold core over the mid MS valley will drag a cold front into the area at the beginning of the period. As it plows into a moist and unstable airmass primed from daytime heating with PWs near 2 inches, a good concentration of showers and thunderstorms will likely be ongoing over the ArkLaMiss Delta region. Some risk of severe looks to continue into the evening hours given the frontal forcing and 20-30 knots of deep layer shear, but these storms should wind down somewhat by midnight with the loss of daytime heating. The frontal boundary will slow down considerably after midnight and limp into central sections by dawn Tuesday. Daytime heating and frontal convergence will support more convection by Tuesday afternoon over the south, but severe threat appears minimal as deep layer shear relaxes. While the drier air spreading into the area behind the front will lead to less overall convection and cooler overnight lows, the August sun will become quite efficient at warming the airmass each afternoon; still being able to boost max temperatures into the lower 90s. This will be the case through Friday as high pressure over the mid MS valley maintains low level northerly flow. As high pressure shifts to the east Saturday, resulting low level easterly/southeasterly flow will finally begin bringing low level moisture back into the area. This will promote a return of diurnal convection heading into the middle of the weekend./26/ && .AVIATION... 00Z TAF discussion: Dissipating TSRA activity was resulting in IFR conds in the nw and se at 2330Z. These conds wl improve before lower flight conditions develop again by 08Z. Most of the current TSRA activity wl dissipate by 02Z but additional TSRA development wl be psbl after 06Z in the north again. Away from TSRA VFR conds wl cont until after 08Z when widespread MVFR/IFR cigs are expected. Conds wl improve by mid Monday morning but scattered to numerous TSRA activity is expected to develop early again. /22/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 74 89 73 90 / 8 44 43 26 Meridian 73 88 74 90 / 7 53 28 42 Vicksburg 75 91 72 91 / 10 42 42 20 Hattiesburg 73 87 74 91 / 7 59 26 56 Natchez 74 90 73 91 / 9 41 37 29 Greenville 72 89 71 88 / 34 40 57 11 Greenwood 74 88 71 88 / 19 46 56 14 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...None. LA...None. AR...None. && $$ TW/22/26
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1025 PM EDT Sun Aug 19 2018 .SYNOPSIS... A weak cold front will drop into the northern forecast area late tonight and Monday, then lift back north Monday night and Tuesday. Another cold front will move through the area Thursday, then stall off the coast into next weekend. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... As of 1010 PM Sunday...Increased POPs to likely over NW half of area for overnight hours, and continued likely POPs along coast toward morning. Increasing shortwave energy from NW and surface front approaching from north expected to increase coverage of showers and tstms overnight as supported by latest HRRR and NAM12. Coverage has already increased past 1-2 hours near old sea/sound breeze bounday between KEWN and KPGV. A few stronger wind gusts will be possible with cell mergers and clusters but main threat will be locally heavy rain and minor flooding. Rest of forecast on track. /Previous discussion/ As of 230 PM Sunday...Precip timing and coverage difficult with mdls showing wide variety of solutions. Think as instab increases with heating thru this aftn will see sct shra/tsra develop with best coverage inland especially along sea breeze. Better coverage will cont inland during the evening and then late tonight models mostly agree best precip chc will be closer to coast. Overall have mainly chc pops thru the evening then low likely near coast late. Limited instab shld keep storms below svr lvls however high precip wtr values will lead to locally heavy rainfall. Lows mostly low/mid 70s. && .SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/... As of 230 PM Sunday...Weak/ill defined cold front will be near nrn tier thru the day with limited forcing aloft. Shld again see enuf sun for highs well into the 80s leading to decent instab. Expect another day with mostly sct shra/tsra with better coverage near coast in morn shifting inland during the aftn. Modest instab and weak shear will again limit svr threat with locally heavy rain a good bet. && .LONG TERM /MONDAY NIGHT THROUGH SUNDAY/... As of 310 AM Sun...A mean upper trough is forecast over the Eastern US through the period while low level southerly flow continues to circulate a very moist airmass across our region with PW values AOA 2". The favorable combination of forcing aloft and moisture/instability in the low levels will result in unsettled conditions through the first part of the week with precipitation chances at or above normal and temperatures at or slightly below normal. Shower and thunderstorm chances increase above climatological norms through mid week as conditions remain favorable for scattered to numerous showers and thunderstorms. Monday night through Tuesday...A weak front is forecast lift back north Monday night and early Tuesday. Highs in the mid to upper 80s through mid week, and overnight lows in the 70s. Wednesday through Sunday...Another cold front will approach the area mid to late week. There are still some timing differences, with the GFS much more progressive and pushes the front through quite a bit faster than the ECMWF. Expect the front to push through the area Thursday, then likely remained stalled off the coast into the weekend as strong high pressure builds in from the north. Expect to see a drier airmass build into the area with lesser precip chances. Highs in the low to mid 80s. Some guidance has lows dropping into the low/mid 60s late week and next weekend. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Short Term /through Mon/... As of 750 PM Sunday...Current VFR conditions expected to persist into overnight, then some sub-VFR CIGs likely developing 08Z- 13Z with IFR threat mainly KPGV and KISO. VFR returning for most of Monday. Scattered showers/tstms lingering along sea breeze will remain in vicinity of KEWN and KOAJ next few hours then expected to diminish. Additional activity expected to develop overnight with short wave energy and surface front approaching from north and enough support to include TEMPO for MVFR SHRA all sites 08Z-12Z. Scattered convective coverage for most of the day Monday. Long Term /Monday night through Thursday/... As of 310 AM Sun...Scattered to numerous showers and storms will produce sub-VFR conditions at times through the period. In addition conditions will be favorable for periods of low clouds and fog early each morning. A cold front will push through the area Wednesday night and Thursday. && .MARINE... Short Term /through Mon/... As of 1020 PM Sunday...No significant changes with update. /Previous discussion/ As of 230 PM Sunday...Winds gusts have been below 25 kts past cpl hours and seas 5 ft outer buoys so will drop SCA rest of today central and srn wtrs, however will likely remain just below. Gradient expected to loosen overnight as weak front sags toward nrn wtrs and stalls thru Mon. SW winds will become light N of Cape Hat tonight into Mon and could see variable dir at times. S of Hat SW winds will cont 15 to 20 kts this evening then mainly 10 to 15 kts late tonight and Mon with still poss some gusts to 20 kts. Seas will subside to 2 to 3 ft N. Over srn tier seas will be mainly 3 to 5 ft tonight and 3 to 4 feet Mon. Long Term /Monday night through Thursday/... As of 310 AM Sun...A weak front is forecast to lift back north Monday night and early Tuesday. S/SW winds return for all waters Tuesday 5-15 kt early increasing to 10-20 kt in the afternoon. Seas 2-4 ft early building to 3-5 ft Tuesday night. Gradient tightens Tue night and Wed, with SW winds increasing to 15-25 kt and seas building to 3-6 ft. Could see a brief period of SCA conditions Tue night into Wed, with best chances across the central waters. A cold front is likely to push through the waters Thursday then stall off the coast into the weekend. Winds will shift becoming NE/E 5-15 kt. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...RF NEAR TERM...RF/JBM SHORT TERM...RF LONG TERM...CQD AVIATION...JBM/CQD MARINE...RF/JBM/CQD
Area Forecast Discussion
National Weather Service Omaha/Valley NE
626 PM CDT Sun Aug 19 2018 .SHORT TERM...(Tonight through Wednesday) Issued at 400 PM CDT Sun Aug 19 2018 At 4 PM, fairly vigorous shortwave trough (by August standards) was digging southeast through central Nebraska, with a 1007 mb surface low over east central Kansas. An area of rain with a few embedded thunderstorms extended from the Ozarks north into South Dakota. Rain amounts over our region so far today have been in the 0.25-1.75 inch range, with the highest totals reported in the Lincoln area. The primary concern/focus of the forecast is the potential for very heavy rainfall this evening and overnight as the surface low in Kansas shifts northward, deepens, and slows. This will place southeast Nebraska and southwest Iowa in a region of strong isentropic lift with PW values near 1.9 inches, and favor the development of a heavy (possible convective) rain band between 7 PM tonight and 7 AM Monday. Recent runs of the NAM/HRRR/and RAP generally support this scenario. Due to the potential for rain rates near 2 inches per hour and training of heavier precipitation, a Flash Flood Watch has been issued for the region. Forecaster confidence in storm total rain amounts in the 2-6 inch range is moderate. There is some potential for the heavier rainfall to occur over the Omaha or Lincoln metros. Rain should slowly dissipate through the day on Monday, with the chance of heavy rainfall falling off quickly during the morning. High temperatures will be mild for August on Monday, with afternoon highs in the low to mid 70`s. Drier weather is anticipated Tuesday and Wednesday, with afternoon highs running in the upper 70`s each day. No hazardous weather is anticipated. .LONG TERM...(Wednesday night through Sunday) Issued at 400 PM CDT Sun Aug 19 2018 After another dry day on Thursday, a chance of thunderstorms returns to the forecast Friday, as a shortwave traverses the northern Plains. Model trends over the last couple days have been trending strong with this shortwave, increasing forecaster confidence in the potential for rainfall. The forecast for next weekend continues to fluctuate, with recent GFS/ECMWF trends favoring dry weather Saturday and a slight chance of showers Sunday. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 623 PM CDT Sun Aug 19 2018 IFR to occasional MVFR conditions are expected through much of the TAF cycle as a strong system brings widespread rainfall to the region through the overnight hours and into Monday morning. In addition, gusty northerly low-level winds are expected to increase overnight as the low pressure system passes through the region. This should create areas of low-level wind shear from 05z-13z or so. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...Flash Flood Watch through Monday morning for NEZ015-033-034- 043>045-050>053-065>068-078-088>093. IA...Flash Flood Watch through Monday morning for IAZ043-055-056-069- 079-080-090-091. && $$ SHORT TERM...Albright LONG TERM...Albright AVIATION...Kern
Area Forecast Discussion
National Weather Service Raleigh NC
933 PM EDT Sun Aug 19 2018 .SYNOPSIS... A cold front will move into central NC tonight, then stall overhead. This boundary will return northward late Monday night into Tuesday. A strong cold front will cross the area late Wednesday and Wednesday night. && .NEAR TERM /THROUGH MONDAY/... As of 930 PM Sunday... Couple of surface boundaries set up across the forecast area this evening. One across the NC/VA border where some persistent convection has been occurring for several hours. Backbuilding precipitation has led to an area of greater than five inches of rain across northern Person County. This is the greatest area of concern at this time. A second, currently inactive boundary a bit south of the first and running more southwestward down US 1 has upper 70s dewpoints southeast of it with some low 70s north of it. Convective allowing models suggest that this may become a focus for convection later this evening as the HRRR in particular shows this area becoming active after midnight. Pushing back to a more synoptic frame of reference, a wave off to the west will continue to push southeastward into the area overnight and may provide some additional support for ascent during the overnight hours. Do not expect much in the way of severe activity, however the slow moving nature of the convection this evening could lead to more flooding issues. Overnight lows generally in the lower 70s. && .SHORT TERM /MONDAY NIGHT/... As of 340 PM Sunday... The sfc boundary is projected to lie close to highway 64 by early Monday. This sfc front will serve as a focus for scattered convection Monday afternoon. Severe parameters a little more impressive with shear values approaching 30kts across the north with MLCAPE values 1600-2000 J/kg. This would suggest that the convection may organize into broken bands, enhancing the threat for locally damaging wind gusts. Convective allowing models suggest that convective will be random, with not much organization. The approach of a stronger s/w, crossing the mid MS Valley, will induce a sly flow over central NC Monday night. This will push the stalled boundary north back into Virginia by early Tuesday. The retreating boundary may trigger additional showers and isolated thunderstorms overnight Monday night. Widespread low clouds Monday morning will inhibit insolation and deter temperature recovery a bit. Once the sun breaks through, convection will quickly fire, adding another hurdle to temperature recovery. Thus, highs Monday will likely stall in the mid-upper 80s. If the extensive low clouds hold on until mid day/early afternoon, then highs across the northern counties may end up 3-4 degrees cooler than forecast. Lows Monday night near 70-lower 70s. && .LONG TERM /TUESDAY THROUGH SUNDAY/... As of 132 pm Sunday... Two main weather stories during the long term: 1. Severe thunderstorm risk late in the day Tuesday. 2. Cooling/Drying trend for Thursday through Saturday. First, the severe weather threat: With the approach of an amplified mid/upr trough, we`ll see deep warm/moist s/sw flow ahead of it and warm sector destabilization on Tuesday. As a prefrontal sfc trough approaches late in the day, in conjunction with increasing deep layer shear with the approach of the mid/upr trough, the ingredients for isolated to scattered severe tstms will come together. Deep layer shear progs, along with forecast soundings and hodographs suggest storm mode will be mostly multi-cell cluster with straight- line winds being the main threat, however there`s enough low level shear to support the potential for a couple isolated supercells. Timing for such a line of tstms appears to be later in the day, or mainly evening hours. Shower and tstm activity expected to wind down overnight. Then on Wednesday, the sfc cold front and upper trough axis are forecast to move through, so will need to keep a chance for showers/tstms in the forecast for Wednesday afternoon, but the best forcing for such activity (and severe storms) will have exited, so any pcpn on Wednesday should be fairly light. Temps Tuesday and Wednesday near-normal. Second, the cooling/drying trend: In the wake of Wednesday`s cold front and upper trough passage, look for cool/dry air advection along with high pressure building to our north. That will set up central NC to have a period of pleasant weather Thursday and Friday, perhaps even lasting through most of Saturday, with temps several degrees below normal (highs in the lower 80s and lows in the upper 50s to lower 60s). There are hints that a coastal trough may bring moisture back into eastern NC over the weekend, but the bulk of that moisture (and rain chances) right now appear to remain mostly to our east and south. && .AVIATION /00Z MONDAY THROUGH FRIDAY/... As of 750 PM Sunday... An upper level disturbance can be seen on water vapor this evening rotating east. There is a leftover boundary from earlier convection just north of KRDU and KRWI this evening and the NSSL WRF is showing current convection across the north pushing south and igniting along this boundary. Other high res models aren`t as impressive, but also are not handling current trends well either. Given the orientation and location of current mesoscale boundaries have kept TAFs advertising this solution. Monday morning, convection will quickly decrease in coverage as the upper level low centers over the northeastern United States. As this happens, another round of low level stratus will be possible. NAM soundings have latched on to this signal with the GFS not as robust (cigs confined to the triad). Given what happened last night and very similar sounding profiles, think the stratus will happen. Some sub IFR restrictions will also be possible towards KGSO and KINT which future TAF packages might need to include. During the day Monday, the upper level low will exit east across the region with another round of showers and thunderstorms possible in the afternoon. Some gusty winds will be possible in any of the heavier showers and thunderstorms as dry air exists in the mid to upper levels. Outlook (00z Tuesday through Friday): The atmosphere will remain moist and unsettled across central NC through mid week, leading to rounds of scattered convection, and lengthy periods of early morning low clouds. A cold front is expected to cross the region Wednesday evening with drier air filtering in behind. This will lead to a period of VFR conditions Thursday and Friday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...Ellis SHORT TERM...WSS LONG TERM...NP AVIATION...Haines
Area Forecast Discussion
National Weather Service Springfield MO
621 PM CDT Sun Aug 19 2018 ...Updated for 00Z Aviation Discussion... .SHORT TERM...(This evening through Monday) A large shield of showers and thunderstorms extended deep into extreme southeast Kansas and the Missouri Ozarks this afternoon. This was in response to an unseasonably strong upper level low pressure system, that was circulating over the central Plains. This feature has a surface reflection centered over east central Kansas, which helped to bring in an airmass rich in moisture, and slightly more unstable. Determining if organized thunderstorms will develop late this afternoon and early evening was the primary forecast challenge today. Some of the CAMS models showed deep convection, while others have not. Shear will be strong for the time of year, however, instability levels are in question. A Special RAOB was performed at 2pm to assess how unstable the Ozarks airmass really was. We are especially focused on the lower distribution of cape, and how much of it exists. The HRRR shows organized line segments to developing within an environment containing 0-3km shear vector magnitudes of around 35 knots. If sufficient low level cape is present, we could experience pockets of damaging winds, and even a couple of spin up tornadoes. Showers and thunderstorms will linger at random late tonight and into tomorrow. South central Missouri could have a marginal to slight risk for additional thunderstorms tomorrow. Look for highs in the low 80s on Monday. .LONG TERM...(Tuesday through Sunday) Fall like weather is expected through the rest of the work week as rain chances end Monday evening. With northwest flow keeping a cool continental airmass over the region, temperatures will warm up into the low to mid 80s on an afternoon basis through Thursday. An upper level speed max is signaled by the models to approach by Friday, bringing a chance for showers and thunderstorms. As mid level heights rise toward next weekend, models do suggest a warming trend, with temperatures back in the 90s. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 621 PM CDT Sun Aug 19 2018 A line of strong to severe thunderstorms are moving across southwest Missouri. The line has cleared KJLN, but KSGF and KBBG will see strong to severe thunderstorms in the next few hours. IFR visibilities/ceilings along with strong winds likely with this line, and the potential for tornadoes will also continue. This line will move east of KBBG and KSGF by 03Z, but still some remaining showers/storms are not out of the question the remainder of the night. Mainly VFR conditions then expected behind the line, although some local MVFR ceilings will be possible in any remaining showers. Another chance for convection will occur late in the TAF period. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...Cramer LONG TERM...Cramer AVIATION...Raberding
Area Forecast Discussion
National Weather Service Shreveport LA
933 PM CDT Sun Aug 19 2018 .UPDATE... Convection quickly diminishing and moving out of our NE zones attm. A remnant outflow boundary remains to the south and west of the complex of storms currently across Central Arkansas attm but not seeing any renewed convection along it and not seeing much in the way of cumulus forming along the boundary in the GOES-16 Nighttime RGB data. For the update, have trimmed pops back to slight chance variety areawide as the HRRR still shows some very isolated convection redeveloping during the overnight hours. Once again have thrown out the latest 00z NAM output as it continues to suffer with convective feedback issues. Concerning temperatures, had to cool fcst mins across our northern most zones where rainfall has resulted in temps below current forecast mins. Likewise, warmed temps up a degree or two along the I-20 Corridor. The true cold front resides across S OK into NW AR attm and with its passage south and east into our region during the afternoon and evening hours on Monday, renewed convection is possible along this boundary. Pop forecast for Monday looks good so no further changes were necessary. Update out shortly...13. && .PREV DISCUSSION... /issued 631 PM CDT Sun Aug 19 2018/ AVIATION... Another low confidence forecast with the 00z TAF package as once again, short term progs are struggling with current convection and future trends. The 18z NAM output suggests we will see a line of convection push through the entire region overnight, effecting all terminal sites and this does not appear likely. GFS is struggling on current placement of convection and appears to be well overdone as well. Have based the 00z TAF package on the latest run of the HRRR which suggests that the TXK/ELD/MLU terminals have the most likelihood of seeing evening convection before most if not all convection dies off late tonight. We will need to watch for renewed convection by late morning into the afternoon hours along a southeastward moving cold front on Monday and have thus added VCTS to all but the TXK/TYR terminals for this. South winds near 10kts overnight will veer quickly to the southwest on Monday with sustained winds near 10-15kts with higher gusts ahead of the southeastward moving cold front. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 79 94 73 95 / 20 50 40 10 MLU 78 92 73 93 / 20 50 40 10 DEQ 72 90 66 89 / 20 10 10 0 TXK 74 91 69 90 / 20 30 10 0 ELD 76 92 70 90 / 20 50 40 10 TYR 79 96 72 94 / 20 20 10 10 GGG 79 95 71 94 / 20 40 20 10 LFK 75 94 75 95 / 20 40 40 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/13