Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/10/20

Area Forecast Discussion...UPDATED
National Weather Service Amarillo TX
601 PM CDT Thu Apr 9 2020 .AVIATION... East and southeast winds will bring low level moisture back into the Panhandles tonight which will result in lowering cigs. At this point it looks like GUY and AMA will stay in the VFR range, but DHT may drop into the MVFR range. DHT is then expected to improve into the VFR range around mid day on Friday. A few showers may try to make a run at DHT or GUY tonight, but confidence in any one shower affecting the TAF sites is low, so did not mention in this forecast. Winds will pick up and become more southerly at all site by late morning on Friday. Speeds will be in the 14 to 22 knot range with higher gusts. && .PREV DISCUSSION... /Issued 348 PM CDT Thu Apr 9 2020/ SHORT TERM...Today through Friday Night. Mid-level water vapor satellite analysis shows Pacific moisture streaming across Mexico, eastern New Mexico and Texas before getting swept into more zonal flow. 500mb RAP analysis shows a closed low over southeastern California and southern Nevada with the mid-level water vapor indicating dry air wrapping around the south and east side of the low with moisture along the north and west side. Models have this upper level low tracking backwards towards the coast of southern California through tomorrow evening before making its trek east Friday night into Saturday morning. Over the next two days, moisture in the lower levels is not a problem but the moisture in the mid-levels is hard to come by. A small shortwave disturbance in the upper levels will form later today across eastern New Mexico with a slight chance for some rain showers in the northwest overnight tonight. A rumble of thunder is not out of the question, however instability is limited with only a couple hundred J/kg of MUCAPE. The better chance for precipitation returns Friday afternoon in the southwest Texas Panhandle and continues in the far southern Texas Panhandle through the evening. Instability is better Friday with 500- 1000 J/kg of MUCAPE and 40 to 50 knot 0-6km effective bulk shear. A dryline feature will set up in eastern New Mexico during the afternoon hours with an 850mb theta-e axis for storms to fire along. The CAMs are indecisive on the potential for storms tomorrow with the chance of an isolated strong to severe thunderstorm or two across the southern Texas Panhandle with a slight chance for a storm in the northern Texas Panhandle where the environment is more stable. Temperatures will remain in the 60s today and tomorrow with mild low temperatures in the 40s. Cloudy conditions today will persist through tomorrow morning but clear in the north and possibly remain in the south. Therefore the chance for storms will linger on the chance for clearing skies in the south and ample heating to break the cap. Winds are expected to become breezy in the northern Panhandles tomorrow under clear skies with winds of 15 to 25 mph. Rutt LONG TERM...Saturday through Thursday. The upper level low pressure system mentioned earlier is progged to translate east across southern Arizona, southern New Mexico, and west Texas by Sunday morning. Overall limited moisture return through Saturday evening warrants low pops across the southeast Texas Panhandle Saturday afternoon. A few storms that develop Saturday afternoon in this area will have the potential to become strong to marginally severe, with hail up to the size of quarters and wind gusts to around 60 mph the primary hazards. A strong cold front is then forecast to dive southward and move through the region late Saturday night and Sunday morning, leading to below normal temperatures for later Sunday through Thursday. NBM consensus pops were utilized durg this time period, which are generally in the slight chance to mid chance range. Wintry mixed precipitation remains possible. However, confidence is very low with respect to the amount of precipitation and type as medium range models continue to disagree on this element. Further refinements to the forecast are expected as time gets closer. 02 && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 15/29
Area Forecast Discussion
National Weather Service Denver/Boulder CO
909 PM MDT Thu Apr 9 2020 .UPDATE... Issued at 900 PM MDT Thu Apr 9 2020 Have scaled the chance for showers back over the urban corridor some tonight as not many are surviving off the higher terrain. A dry airmass is pushing in from the east into the state, visible even on IR satellite imagery. A surface low will begin forming to the lee of the Rockies after midnight to create drier conditions over the mountains, foothills and urban corridor. The low will increase south winds across the east plains, gusting to 25 mph by morning. && .SHORT TERM...(This evening through Friday) Issued at 157 PM MDT Thu Apr 9 2020 A weak short wave appears to be getting ejected this afternoon from the closed low over southern NV. This energy is getting disbursed into the deformation zone over northern and western CO. RAP shows limited weak upward QG omega in the mid and upper levels around 00z. The high res model solutions generate much of the qpf over the mountains through this evening, with little movement to the east. For this reason, will keep the pops confined to the western part of the forecast area. There may be a few sprinkles near the foothills, but do not expect those showers to make it east of I-25. In the mountains, sct to likely pops with localized accumulation up to 2 inches possible, but that should be it. The frontal boundary appears to be settled along the foothills and Palmer Divide at this time. Northeast surface winds this afternoon to transition to east/southeasterly this evening. By Friday, the closed upper low over southern NV retrogrades to the west, and a weak disturbance embedded in the northwesterly flow over CO brushes across the area. In the morning, gusty south/southwest winds can be expected across the northeast and east central plains, they then decrease and become west/northwest in the afternoon. NAM12 soundings show favorable instability after 21z in the afternoon with MU CAPES around 350 J/KG for Denver. Enough instability for some scattered showers in the afternoon and evening. High temperatures will jump back to near 70. As far as the fire danger goes, the danger may be elevated along the northern border. However the gusty winds will be strongest in the morning, so this will not coincide with the driest conditions in the afternoon. Therefore, no fire weather highlights are planned at this time. .LONG TERM...(Friday night through Thursday) Issued at 157 PM MDT Thu Apr 9 2020 Isolated showers and thunderstorms should linger in the evening hours Friday. Any precipitation is expected to be light and short lived. Saturday will be warm again ahead of a strong cold front tracking south across Rockies. Highs in the 60s to lower 70s are expected again for most of the lower elevations. The strong cold pushes south across the area Saturday late afternoon and evening bringing much colder air. At the mid and upper levels, flow aloft becomes northwesterly as a trough moves across the Central Rockies. This along with the left exit region of the jet is expected to produce snow Saturday night and Sunday. Northeast surface winds resulting in an upslope flow will enhance lift west of I-25 and may bring higher snowfall amounts here. Over the past day, models have sped up this system with most of the snow expected to fall Saturday night and Sunday. At this time, heaviest snowfall is expected across northern Colorado. This lines up with the left exit region of the jet. Models also show weak CAPE Saturday night and Sunday, so locally heavy snowfall could occur due to convection. Decent agreement among the models the airmass dries out Sunday evening. Should be light snow/flurries in the evening along the Front Range, By late evening, snow should be done. It will be quite cold Sunday night/Monday morning with teens for most locations. If it clears, single digits will be possible. Northwest flow aloft will persist through next week. This will keep cold air over the area and temperatures will stay well below normal. Models are advertising a couple systems will be embedded in the northwest flow aloft and may bring snow to the area. The first one is on track to move across the area late Monday. This will be fast moving and bring a brief period of snow sometime Monday afternoon and Monday night. Much more uncertainty exists with the second system. Models show anywhere from late Tuesday to Thursday for timing of this second system. So will broadbrush PoPs for this time frame until the forecast becomes more clear. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 900 PM MDT Thu Apr 9 2020 A batch of showers will push northeast across the metro area through midnight, however the airmass is quite dry and stable, and any weak showers that develop should mainly remain west of Interstate 25. Northeast winds will transition to southeasterly this evening, then south/southwesterly overnight, increasing to 12 to 15 kts sustained. Next chance for rain showers will be after 21z Friday as a weak disturbance brushes across northern CO late in the afternoon. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Kriederman SHORT TERM...Cooper LONG TERM...Meier AVIATION...Kriederman
Area Forecast Discussion
National Weather Service Grand Junction CO
435 PM MDT Thu Apr 9 2020 .SHORT TERM...(Tonight through Friday night) Issued at 228 PM MDT Thu Apr 9 2020 The deep area of low pressure continues to spin over Nevada and California today while we stayed between this feature and an area of clouds and convection to our southeast. A vort lobe is rotating around the area of low pressure and has, and will continue to be, the focus of convection this afternoon. A few lightning strikes have already been seen near Green River and at Canyonlands in Utah and this trend will continue as the lobe continues to move across the region. The HRRR has performed well with this feature and remained steadfast in convective placement. It`s also showed some storms firing over the Grand Valley between 3PM to 6PM for several successive runs so will be interesting to see if this pans out. Unfortunately, the atmosphere is quite dry so don`t expect much in the way of appreciable precipitation but a quick downpour can`t be ruled out. The most likely scenario with the storms will be some gusty outflow winds from the storms. As they`re fairly weak, gusts will range from around 30 to maybe 40 mph, if that. As is usually the case, most convection will die down near sunset though a few stray showers/storms might continue along the Continental Divide. Tomorrow, more of the same as the cutoff low drops southward some and puts us more in a col. Even so, models are picking up on minor instability allowing another round of weak convection in the afternoon and evening hours. Again, winds will be the biggest threat. Temperatures remain nice and warm but this changes drastically over the weekend so enjoy the nice weather while you can. .LONG TERM...(Saturday through Thursday) Issued at 228 PM MDT Thu Apr 9 2020 The deep area of low pressure finally takes a significant southward turn on Saturday and keeps us dry. Surprising, after much of last week showed at least `some` precip from this feature. Have no fear though as a strong cold front sets its sights on us. Showery activity will start ahead of the front around noon on Saturday up north and shift southward through the day. The heaviest precip still looks like it will occur along and behind the front, generally for the northern half of the CWA along the Continental Divide. Several inches of snow look possible by Sunday morning but for the highest elevations of the Park, Flat Tops, Elkheads, and leading up to Vail Pass. Temperatures will take a nosedive once the front passes through with highs and lows dropping anywhere from 8 to 12 degrees. Most precip ends by Sunday afternoon but not for long. A deep trough sets up over much of the CONUS by Monday morning and will remain the main weather player for much of the week. As we`ll be upstream of the trough axis, flow will be north to northwesterly across the area allowing much cooler temperatures to move in. As this occurs, a weak wave will swing through the flow bringing another chance for some precipitation Monday afternoon into Monday evening for much of Moffat and Routt counties and eastern portions of Rio Blanco county. Eagle and Pitkin counties will also see some rain/snow as the disturbance moves through. Forecast snowfall amounts, currently, look to be in the 1 to 3 inch range which makes sense as the available moisture is limited and the wave will move through very quickly. This can always change, however, if the wave shifts a bit further eastward...something we`ll keep an eye on. Outside of the precip, the biggest concern will be anomalously cold temperatures. As mentioned, north to northwesterly flow will remain over the area, even after the wave moves through, so cooler temperatures will continue. H7 temps look to drop to between -5C down south to near -10C up north. This will be reflected at the surface with both high and low temperatures about 8 to 12 degrees below average for this time of year. Models originally highlighted Monday morning being the coldest day with Tuesday a few degrees warmer. Now with the wave, increased cloud cover may keep Monday a bit warmer with Tuesday the coldest. It`s really neither here nor there as both Monday and Tuesday morning low temperatures will be about 8 to 12 degrees below average for this time of year. Certainly a concern for anyone working in the agricultural field. Might see a freeze warning issued if models continue to bring in the cold air. Another quick wave looks to move in Tuesday evening and have moved out by Wednesday morning. Very similar to the previous wave on Monday as far as areas impacted though QPF amounts do look to be lower. After that, flow remains northwesterly which will keep temperatures on the cool side and below average. The areas mentioned above, that will see the precip, will see mostly cloudy skies while remaining areas will likely see variable cloudiness through Wednesday and then more sunny skies Thursday onwards. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 430 PM MDT Thu Apr 9 2020 Scattered showers and few embedded storms have developed across the area each capable of 30 mph wind gusts. They should persist for the next 3-6 hours while gradually moving northward before dissipating tonight. Another round of orographic showers are possible tomorrow afternoon. && .GJT WATCHES/WARNINGS/ADVISORIES... CO...None. UT...None. && $$ SHORT TERM...TGR LONG TERM...TGR AVIATION...TGJT
Area Forecast Discussion
National Weather Service Marquette MI
737 PM EDT Thu Apr 9 2020 .SHORT TERM...(This evening through Friday) Issued at 421 PM EDT THU APR 9 2020 WV imagery and RAP analysis indicated a mid/upper level low south of James Bay with troughing through the Great Lakes. At the surface, gusty northwest winds prevailed between a trough into northern Quebec and high pressure over the northern Plains. A shortwave trough dropping south through Upper Michigan combined with deep moist nw cyclonic flow and 850 mb temps to around -8C supported sct snow showers through the region. The weak instability with added lake moisture and diurnal heating has supported some isold heavier shsn with radar returns at or above 30 dbz. Tonight, with the shrtwv moving to the south of the area, decreasing 850-700 mb moisture, and the loss of diurnal heating, expect the snow showers to diminish this evening. However, 850 mb temps to around -12C with favorable low level conv will sustain some stronger snow showers into west central Upper Michigan where additional accumulations of around an inch are possible. Lower amounts are expected over the eastern cwa where drying and lowering inversion heights are more prominent. Friday, any lingering snow showers will diminish during the morning as high pressure builds into the area with developing anticyclonic flow and drier air moving into the area. Even with some sunshine during the afternoon, highs will struggle into the mid 40s north and the lower 40s south. .LONG TERM...(Friday night through Thursday) Issued at 417 PM EDT THU APR 9 2020 Friday night we`ll remain under colder than normal NW flow aloft but with mid-level heights rising as the northern edge of surface ridging passes overhead Upper Michigan. As this ridge moves by, winds go light and with clouds clearing out, temps should cool off nicely by April standards, with temps falling into the low 20s and perhaps even upper teens interior for lows. That ridging is expected to break down into more of a zonal mid-level flow for the rest of the weekend with temps remaining below normal for this time of year. Then things start to get interesting. A southern stream closed upper low is expected to eject out of the southwest and open up into a wave. As it rides along the baroclinic zone a strong area of low pressure will develop, then further deepen Sunday as a northern stream wave phases in. Despite a surface low track that`s pretty consistent in the models from about Illinois to Lake Huron - normally a bit south and east for maximizing snow in our area - the system stays well tilted with height such that the 700 mb low takes a very favorable track for heavy snow. Looking at things another way, the top CIPS analog from the 00z cycle of the GFS at forecast hour 96 is the March 13, 1997 storm that produced areas of two feet+ of snow. The top three analogs are all significant spring snowstorms and only one or two of the top ten analogs were not snowstorms. The Ensemble Situational Awareness Table for the 00z NAEFS paints this cyclone, at least so far, as generally a once every 1-2 years event (for this time of year), so not particularly extreme but still significant nonetheless. However, there was still some spread in the individual GEFS and GEPS members last night and it`s quite possible that once they coalesce into a more coherent ensemble mean low track these values tick up. For POPs and QPF, tried to slow things down on Sunday since the NBM always brings things in too fast, and with such an amplified system these often end up coming in slower than initially modeled. So for the day Sunday, just have light rain over the south mixing with snow north with barely any accumulation through the daylight hours. But by Sunday night as the 700 mb low closes off and advances north through Wisconsin, precipitation will overspread the entire area form south to north through the night, initially as rain east but quickly changing to snow central and west. The exact track of the surface and 850/700 mb lows will still depend on the exact timing of the phase, but for now the best bet is for moderate to heavy snow central and west and a mix of rain and snow east, changing over to all snow by late Monday afternoon. 850 mb temps falling from -7 to about -11 C through the day along with strong northerly flow should allow for significant upslope and lake enhancement as well. Don`t want to advertise amounts just yet since we`re still four days out but significant snow accumulations look likely with major amounts possible in the upslope regions/lake-effect belts. With the wind added in, blowing snow and lakeshore flooding will be concerns as well so this looks like a classic all-hazards late season winter storm. As the low slowly pulls away Monday night and Tuesday, lake-effect snow showers will likely continue in the NW wind snow belts before subsiding Tuesday night. After that, the story next week is the cold (by April standards). CPC continues to advertise widespread below normal temperatures and 700 mb temps in the GEFS are colder than anything in the M-climate database. Because the NBM is tied to statistical (and therefore warmer) guidance, lower high temps Tuesday and Wednesday by several degrees. With 850 mb temps bottoming out at around -13 C on Wednesday, a few days in a row with highs not cracking the freezing mark looks possible if not likely. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 736 PM EDT THU APR 9 2020 Tricky aviation forecast tonight as ceilings look to briefly lift into VFR as we continue to lose daytime heating this evening, but as colder air aloft continues to stream overhead MVFR ceilings may return overnight/early Friday morning. KCMX/KSAW look like they will mostly stay out of any overnight snow showers activity, so for now have VCSH mentions to hint towards the potential. These snow showers look like they will be more widespread out west later tonight, so did keep prevailing snow showers at KIWD. Did not reduce visibilities much as soundings look rather inverted still overnight. This colder air and enhanced pressure gradient over the region looks to keep gusty NW to N winds in place. Throughout the morning/early afternoon hours on Friday, clouds scatter out and winds start to relax from west to east across all terminals as high pressure moves in. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 421 PM EDT THU APR 9 2020 Expect northwest gales to continue over central and eastern Lake Superior through this evening. Over western Lake Superior, 20-30kt winds will be the rule. Winds will then diminish from w to e on Fri as a high pres ridge approaches and arrives by evening. Winds will fall off blo 15kt Fri night. Although a low pres trough will pass across Lake Superior Sat night, winds should remain mostly blo 20kt Sat thru Sun aftn. Low pres will then organize over the Southern Plains on Sun. This low will rapidly deepen as it crosses the Great Lakes region Sun night/Mon morning. By Mon evening, deep low pres will be located s of James Bay. This strong system will likely bring gales to all off Lake Superior late Sun night/Mon. Strongest winds, possibly high end gale and potentially even a short period of storm force winds, will occur across the e half of Lake Superior on Mon. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning until 2 AM EDT Friday for LSZ244-245-248>251- 264>267. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...RJC AVIATION...Ritzman MARINE...JLB
National Weather Service Raleigh NC
910 PM EDT Thu Apr 9 2020 .SYNOPSIS... A cold front will move east of the area tonight. Behind the front, high pressure will build into the region through Saturday. A strong storm system will move across the Southeast late Sunday and into Monday. && .NEAR TERM /THROUGH TONIGHT/... As of 910 PM Thursday... 00Z surface analysis showed the cold front extending WSW to ENE near the NC/VA border, with a weak low migrating along the front over SW VA. Winds have dropped off in many locations, though some strong wind gusts continue sporadically. RAP guidance shows the pressure gradient continuing to weaken east of the mountains overnight, then perhaps tightening a bit late tonight as the elongated vort max over the Midwest dives toward NC. Thus we could see some wind gusts pick back up prior to sunrise and stronger wind gusts during the day on Friday. Otherwise, it`s a relatively quiet night with lows dropping into the mid 40s to lower 50s and a few mid-cloud areas as the aforementioned vort max approached. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 345 PM Thursday... Quiet weather is expected with high pressure building in and rising heights aloft, although another day of brisk gusty winds is expected within deep subsidence and a dry column. Should see sustained winds of 12-20 mph with gusts to 20-30 mph, a shade less than we`re seeing today, highest across the northeast sections where models show stronger winds through the mixed depth. The CAA and much lower thicknesses (30-40 m below normal) will balance with the strong April sun to support temps in the upper 50s to lower 60s. Winds will diminish by evening, with good radiational cooling Fri night beneath clear skies, and with these low dewpoints, many locations (mainly across the N and W) could see patchy frost. Lows in the mid 30s to lower 40s. -GIH && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 225 PM Thursday... Saturday and Saturday night: Surface high centered over the area on Saturday will shift east off the mid-Atlantic coast Saturday evening and night. Weak ridging aloft will briefly build over the Southeast and into the mid-Atlantic Saturday night ahead of the next system approaching the region. Generally expect highs in the mid 60s and lows in the mid to upper 40s. Sunday through Monday night: Slowed the timing of the next system based on the latest model solutions, otherwise little has changed for the system moving into the area Sunday/Sunday night. This low will slowly make its way through the Southwest on Saturday before getting caught in a deepening northern stream trough diving into the plains and opening into a shortwave. The shortwave low will swing east through the southern Plains/ARKLATEX on Sunday, then northeast through the MS Valley toward the Great Lakes Sunday night and through the Northeast/New England on Monday. At the surface, the low that develops in the lee of the Rockies will strengthen as the it moves east through the Plains and MS Valley on Sunday. The attendant cold front will push east toward the area Sunday night as the parent low lifts north-northeast into the Great Lakes. Details regarding the timing of the front and the evolution/track of the low are coming into better agreement. Timing for best rainfall chances is still between 12Z Sunday and 00Z Tuesday with the fropa and cold Canadian high pressure quickly following Tuesday eve/night. This system has the potential to result in some significant rainfall amounts across central NC as the latest guidance suggests 1-3 inches are possible across the area. There is also the potential for some thunderstorms with the pre-frontal convection, though that will depend on the timing and forcing so confidence in coverage and intensity is still a bit low. Expect temperatures to moderate from Sunday to Monday as return flow off the Atlantic and southerly flow from the Gulf ahead of the front advect warm, moist air into the region. Tuesday through Thursday: A lot of uncertainty for mid-week as the medium range models are significantly different. The ECMWF has a low developing over the Gulf and lifting northeast into the area Tuesday night/Wednesday while the GFS suggests is slower and farther south and east with the low, keeping central NC largely dry and cool until Thursday. As a result forecast confidence is very low, but will keep slight chance/chance of rain in the forecast between Tuesday night and Thursday night to account for uncertainty. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... As of 735 PM Thursday... VFR will continue through the TAF period as a cold front has pushed through the area and brought drier air to central NC. Main aviation concern will be strong WNW winds. Gusty winds should fall off to around or below 12kt by 02Z and then sporadically gust at 15-20kt prior to 13Z as an upper disturbance swings across the area, perhaps with a band of mid clouds, increasing to around 25kt (more NW) thereafter and continuing for most of the day. Looking beyond 18Z Fri, VFR conditions will hold through Sun morning as high pressure builds over the area. A storm system will approach from the SW from midday Sun through Sun night, bringing a high chance of stormy sub-VFR conditions and gusty/erratic winds. Improvement is expected Mon morning as the system departs, with VFR conditions dominating through Tue beneath high pressure. -GIH && .FIRE WEATHER... As of 900 PM Thursday... Winds will increase once again Fri morning, although they may not be quite as strong as today. Sustained speeds of 12-20 mph with gusts to 20-30 mph are expected, starting by mid to late morning and persisting through mid afternoon, after which time winds will start to subside. These winds will further dry out the fine fuels, including those that saw rain last night and this morning. Relative humidity is expected to be low once again Fri, with both temps and dewpoints running lower, yielding min RH levels of 22% to 28% in the afternoon. These conditions will once again lead to an increased fire danger from mid morning through much of Fri afternoon across all of central NC. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...BLS NEAR TERM...BLS SHORT TERM...Hartfield LONG TERM...KC AVIATION...BLS/Hartfield FIRE WEATHER...Hartfield