Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/23/16

Area Forecast Discussion
National Weather Service Amarillo TX
633 PM CST Thu Dec 22 2016 .UPDATE...An ejecting vort max from upper low over northern Arizona has resulted in increasing precipitation coverage across eastern New Mexico and the western Texas Panhandle. Have updated grids to increase PoPs along projected path of precipitation band and to account for possibility of mixed precipitation along the core of this band. As precipitation band moves east across the region, drier air will filter in behind the vort max along with increasing downslope winds. This should effectively end any further chances for precipitation by Friday morning except over the far southeastern Texas Panhandle. Bieda && .PRELIMINARY POINT TEMPS/POPS... Amarillo TX 32 58 32 64 42 / 60 5 5 0 20 Beaver OK 31 58 26 60 42 / 60 5 5 0 40 Boise City OK 28 55 26 57 34 / 50 5 0 0 20 Borger TX 35 61 33 65 45 / 60 5 5 0 30 Boys Ranch TX 33 60 30 65 40 / 80 5 5 0 20 Canyon TX 31 58 32 65 41 / 60 5 5 0 20 Clarendon TX 32 59 33 64 45 / 50 10 5 0 30 Dalhart TX 31 57 25 59 36 / 70 5 0 0 20 Guymon OK 32 58 26 62 40 / 60 5 5 0 20 Hereford TX 32 58 32 64 41 / 70 5 5 0 20 Lipscomb TX 32 59 28 61 45 / 60 5 5 0 50 Pampa TX 32 59 32 63 44 / 50 5 0 0 30 Shamrock TX 33 56 31 61 47 / 50 20 0 0 50 Wellington TX 33 56 33 62 49 / 50 30 5 0 50 && .PREV DISCUSSION... /Issued 526 PM CST Thu Dec 22 2016/ AVIATION...00Z TAFs...Another band of precipitation is approaching the Panhandles this evening, with KDHT expecting mixed precip thru 03/06Z. This precipitation band should arrive at KAMA and KGUY BTWN 23/02Z and 23/04Z. CIG and VIS could briefly drop with this band, with IFR to MVFR conditions possible. Will monitor and amend as necessary. Otherwise, as the precipitation band moves thru in association with passing weather disturbance, southerly winds will increase to BTWN 15 to 25 kts at all terminals. Winds will veer to the southwest around 20 to 30 kts as upper disturbance clears the region AFT 23/10Z with VFR conditions at all terminals thereafter. Bieda PREV DISCUSSION... /Issued 353 PM CST Thu Dec 22 2016/ Discussion... Noteworthy items include the ongoing precipitation which has impacted visibilities at times earlier across the local area, as well as the windy conditions forecast this weekend. Simulated reflectivity from the HRRR and NAM 4km both have a break in precipitation. Precipitation should push out northeast by late afternoon/early evening with a small break in precipitation behind these showers. But it wont be too long behind this break for precipitation to pick back up. Temperatures are warm enough now that the entire forecast area is at or above freezing at this point (20Z). This will help keep our chances for snow limited as the lower levels are forecast to stay above freezing for a good portions of the next 24 hours. I`m not really worried about frozen precipitation at the surface at this time. Guymon is the only site reporting snow at 20Z, and even then this will not last much longer. There is also some warm air advection going on today along with some dry layers in the forecast soundings which should hamper our frozen precipitation chances at the surface as well. I am expecting rain showers tonight for the remainder of this precipitation event. Big story will be this weekend, mainly Christmas day as conditions are forecast to be windy. Showers and thunderstorms will be possible on Saturday night and into Sunday as a large upper level trough approaches the Four Corners region. The greatest chance for precipitation will remain along the eastern half of the Panhandles. Models are also hinting at some instability across the area, so there is a small chance for some isolated thunderstorms that night, mainly for our counties across the east. Severe weather is not expected at this time. Lingering showers and a few rumbles of thunder on Christmas Day will rapidly give way to clearing skies and drying conditions. Wind speeds around 30 to 35 mph with gusts to around 50 to 55 mph are likely in some areas. These strong winds coupled with dry relative humidities will result in conditions favorable for explosive fire growth. Also, any outdoor holiday decorations could be thrown around as projectiles given the windy conditions forecast across the local area. Sunday evening through Thursday Once the wind dies down on Sunday night, fairly tranquil weather conditions are expected through mid- week. Upper level flow will become more zonal, and then southwesterly as a weak upper level ridge builds over the Gulf of Mexico, and another upper level low churns in the Pacific off the Baja Coast. The evolution of this system could bring us another chance for precip later in the week, but right now it appears that a strong surface high pressure could keep the weather fairly quiet the majority of the week. FIRE WEATHER... Very windy and rapidly drying conditions are expected across the Panhandles on Christmas Day. This will lead to elevated and probably even critical fire weather conditions across a portion of the area. Relative humidity values will drop throughout the day and approach 20 percent during the afternoon. Southwest winds will increase by late morning to around 30 to 35 mph with gusts up to 50 mph. Fire officials should closely monitor the forecast for updates in the days leading up to this event. && .AMA Watches/Warnings/Advisories... TX...None. OK...None. && $$ 98/29
Area Forecast Discussion
National Weather Service Denver/Boulder CO
333 PM MST Thu Dec 22 2016 .SHORT TERM...(This evening through Friday) Issued at 333 PM MST Thu Dec 22 2016 A potent Pacific storm system have moved onshore the U.S. near San Diego and will continue to move northeast today. By tonight the 500 mb trough axis will be located across eastern Utah to central Arizona. Colorado will be under a moist south- southwest flow. Wind direction is not favorable for advisory level snows in the mountains, but areas above 9000 feet could see up to 6 inches. The HRRR, RAP, and ESRL HRRR have been showing mesoscale bands forming across Summit County tonight, increasing our confidence in the potential for 3-6 inches, with locally higher amounts possible. The northern mountains should see 3-5 inches. By the time the rich Pacific moisture crosses the continental divide in Colorado, the majority of the precipitable water will have fallen as snow across the southwest and central mountains, leaving the east slopes of the Front Range foothills dry tonight and tomorrow. There is ample model agreement in a dry scenario from Weld County west to the Front Range and west of I-25. But the weather could still be very interesting tonight across the plains of northeast Colorado. The Pacific storm system dug a ways south and tapped into sub- tropical moisture, resulting in a plume of relatively warm moist air above 750mb. HRRR, RUC, EC, NAM, and GFS soundings all indicate a layer of +4-5C temperatures 2000 feet off the ground. Wet bulb effects of evaporating precipitation into that layer do not look like enough to drop the temperature in that layer cooler than +1-2C. HRRR and and ESRL HRRR both show a band of light precipitation forming east of the Denver metro area after about 2 AM and moving northeast. QPF amounts will be 0.05 or less associated with the band. Given the warm layer above surface temperatures in the upper 20s, freezing rain is a real possibility tonight. Confidence in this scenario is low for precipitation forming across the Eastern Plains, but higher near the Kansas border. However, if precipitation forms like the high res models indicate, confidence is relatively high it would fall as freezing rain given the thermodynamic profiles tonight. Any accumulating ice would result in slick bridges and overpasses and potentially slick spots on the rest of the highways and roads. Any precipitation that forms should exit the state before sunrise Friday. Tomorrow...any ice accumulation across Eastern Colorado should melt quickly with temperatures warming above freezing by 9 or 10 AM and high temperatures on Friday reaching the low 50s most areas east of the mountains with clearing skies. Snow in the mountains should taper off by midday after the trough axis moves northeast into Kansas/Nebraska and a much drier northwest flow impacts Colorado. .LONG TERM...(Friday night through Thursday) Issued at 333 PM MST Thu Dec 22 2016 Dry and mild weather will prevail Friday night through most of Saturday, before the next storm system begins to impact the area by Saturday afternoon or evening (Christmas Eve). Q-G lift will be increasing by nightfall with snow likely developing in the mountains despite the strong southerly flow with poor orographics. Surface low pressure will move into eastern Colorado and deepen overnight. By Christmas (Sunday) morning, the upper level trough will begin to swing into the state, with strong Q-G lift noted right over the forecast area. Models remain very consistent regarding the path of the upper low right across the Denver area. With this track, we could still see snow spread down onto the plains. However, this would only be a brief shot before strong downslope kicks in and leads to strong gusty west/northwest winds over the plains. The mountains will continue to see snow and blowing snow through most of Christmas with strong orographics and sufficient wrap around moisture. Accumulations should be moderate, but hard to pin down amounts this far out. Initial thoughts for the high country would be in the 4-8 inch range. It should be noted we can`t be totally confident in the solutions despite their excellent agreement, as the storm itself is still well out over the Pacific. These dynamic systems can sometimes develop farther south so will continue to monitor and adjust forecasts as necessary. Beyond that, the weather should be quiet by Monday and most of Tuesday, before the next weather system moves in from the northwest in strong flow aloft. This should bring more snow to the high country and bouts of gusty winds to the entire forecast area late Tuesday into Wednesday and Thursday. Temperatures should average near normal levels, with perhaps a slight downward trend through Thursday. At this time, don`t see much threat of any snow in the lower elevations. && .AVIATION...(For the 18Z TAFS through 18Z Friday afternoon) Issued at 333 PM MST Thu Dec 22 2016 Winds will remain light all terminals throughout the period. VIS also not expected to be an issue. The challenge for tonight is the potential for a rare but potentially high impact freezing rain event at KDEN. Overnight surface temperatures will be in the upper 20s. The high resolution models develop a band of light precipitation very near KDEN and then move it northeast. Best bet on timing is around 2 AM for onset of precipitation at KDEN. Have included freezing rain from 09-12Z in the KDEN TAF even though the chance of any precipitation falling at KDEN is low, because of the potential impacts to the airport. If precipitation develops, MVFR conditions are likely. Radar trends will be watched very closely for the development of the precipitation band tonight. Any ice accumulation will be light and should melt quickly after 9 AM as temperatures warm above freezing. Friday during the day looks like a good day to fly in and out of the Denver metro area. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Schlatter LONG TERM...Barjenbruch AVIATION...Schlatter
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
654 PM CST Thu Dec 22 2016 ...Dense fog advisory issued for coastal counties and Coastal waters... .DISCUSSION...Marine/advection fog has formed over portions of the Laguna Madre and the Nearshore Gulf waters in association with a weak cold front and warm dew point air flowing over slightly cooler coastal waters. Local Coast Guard station, observation sites and webcams are reporting or indicating visibilities dropping below one quarter mile or less. Conditions should persist or worsen over the next several hours with the fog advecting inland impacting coastal sections of Willacy and Cameron counties. Will continue to monitor the progress of the fog and if Dense fog moves or develops farther inland the Dense Fog Advisory may have to be expanded. && .DISCUSSION...Updated for latest marine discussion below. && .MARINE...A dense fog advisory has been issued for the Laguna Madre and the near shore gulf waters through mid morning Friday. See discussion above. && .PREV DISCUSSION... /issued 604 PM CST Thu Dec 22 2016/ DISCUSSION...Updated for latest aviation discussion below. AVIATION...A weak cold front has passed south of all TAF locations with Northeast winds expected through the evening. An area of sea fog/low stratus deck has formed over the Laguna Madre and pushed inland affecting KHRL with IFR cigs and LIFR cigs at KBRO. Meanwhile...conditions at KMFE will lower a bit more slowly starting out with MVFR cigs. Conditions will deteriorate through the overnight hours and do expect another round of LIFR cigs/visbys as low level moisture lingers. However...there is still some uncertainty as to how low visbys will drop as a wind shift to the SE occurs overnight into the morning hours Friday. Conditions will improve to VFR levels by Friday afternoon. PREV DISCUSSION... /issued 244 PM CST Thu Dec 22 2016/ SHORT TERM (Tonight through Friday Night): The biggest issue will be the fog forecast for tonight. Signs point to another round of dense fog for the lower valley as a weak front essentially stalls over the area, and the location of the boundary will impact fog development. The HRRR shows persistent dew points in the mid to upper 60s and very light winds for the lower valley tonight, supporting heavier fog formation. The NAM forecast sounding at 12Z for BRO shows a saturated profile below a low level inversion at around 1200 feet, and therefore placed a mention of dense fog for that area in the forecast for tonight. The oncoming shift will once again need to refine the effort as trends shape up. Southeast winds should reestablish themselves during the day Friday as high pressure shifts east and pressures fall across the high plains ahead of a short wave trough. Rain chances will end for the CWFA as any remnant surface boundary dissipates or gets pushed back north of the area. Partly to mostly cloudy skies will continue and temperatures will remain above average during the short term with 50s and 60s at night and mid 70s to near 80 on Friday. LONG TERM (Saturday through Thursday): As the next H5 trough races northeast from the four corners into the northern plains, a surface reflection low will sweep through those region, with a cold front trailing around it. Saturday into Sunday will see modest southeast winds wrapping into this develop storm system, which will help push local temperatures will into the 80s, especially on Christmas Sunday. Models continue to back off the progression of the tail end of the front, keeping our region in the warm sector. Deeper Gulf moisture and weak instability will possibly spark a few showers from time to time Monday into Tuesday, depending on the proximity of the front. With the showers in the vicinity and increased cloud cover, highs early next week will be slightly lower than the weekend, but still running above normals for the last week of the year. MARINE: Now through Friday night: A weak cold front will pass slowly through the Lower Texas coastal waters but will quickly dissipate and allow surface high pressure to resume over the western Gulf of Mexico. Light to moderate winds and low to moderate seas will prevail along the Lower Texas Coast during the forecast period. Saturday through Monday: Onshore flow continues through the weekend into early next week as the next storm system moves through the central plains. Models continue to push the storm track further north, so gradient will not be very tight as it crosses the plains. Thus the southerly winds will likely not reach advisory criteria through the period. Strongest winds would be on Sunday, with possible 15 to 20kt range for the Laguna Madre. Continuous southeast flow will keep seas elevated through the period, generally 4 to 5 feet. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...Dense Fog Advisory until 9 AM CST Friday for TXZ256-257. GM...Dense Fog Advisory until 9 AM CST Friday for GMZ130-132-135-150- 155. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 69/59/62
Area Forecast Discussion
National Weather Service Caribou ME
930 PM EST Thu Dec 22 2016 .SYNOPSIS... Low pressure will pull away from the region tonight into the Maritimes. High pressure is expected to build across the area on Friday. A cold front will cross the area Saturday and strong high pressure will build toward the region from the northwest Sunday. && .NEAR TERM /THROUGH FRIDAY/... 9:30 PM...The last of the precipitation will be ending over the next hour in eastern Washington County. The main concern over the next few hours is for areas of fog with reports of locally poor visibility. The fog situation should improve overnight as the pressure gradient increases and the wind picks up a bit. A weak weather disturbance is visible on satellite moving across Quebec that may clip northern areas with a snow shower in spots overnight. Made some adjustments to the grids for the remainder of tonight based on the latest observations, and the latest satellite and radar trends. Previous discussion... Snow will be winding down this evening with temps remaining above normal into Friday. 18Z analysis showed low pres moving across the state w/the 2nd low moving off the southern New England coast. The latest runs of the RAP and HRRR in line w/this analysis. It looks like low pres will merge off the coast of Maine and pull away tonight. Snow has been winding down across the n per the latest radar loop. Reports of moderate snow across portions of central and interior Downeast this afternoon. Radar indicated decent returns in these areas. Slight adjustments were made to the QPF and snowfall amounts keeping 1-3 in the aforementioned areas and less than 1 inch across the northern areas. Coastal areas were seeing rain as temps warmed well into the 30s. Another band of precip is set to move across the interior Downeast and coastal region later this afternoon into the evening. This precip associated w/50 kt jetstreak at 700mbs. Temps look like they will cool down allowing for rain to go to a period of snow along the downeast coast w/some accumulation before ending. Upper trof moving across the region will aid in ending the snow near or after midnight. Cooler air will filter into the region overnight allowing temps to drop back into the teens and 20s. Low lying areas will see 15-20 as far s as into the Central Highlands and interior Downeast. This could lead to some wet roads icing back up overnight. At the sfc, high pres to our s is forecast to ridge across the region on Friday while aloft a disturbance is forecast to slide across the region. Mid level lapse rates look like they will steepen and there is some weak forcing. This would allow for the potential for some showery type of precip. The caveat to this is that the deep moisture is lacking w/the bulk residing at 850 mbs. Attm, isolated snow showers/flurries possible and kept precip chances 20-30% across the western areas. Daytime temps will continue to run above normal w/upper 20o to lower 30s northern 1/2 while central and downeast forecast to hit mid 30s. The coast will hit 35-40F. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/... High pressure will slide east of the mid atlantic coast Friday night. As it does so, high clouds will begin to increase overnight. Low temperatures will be mild for this time of year with low to mid 20s across much of the area. Clouds continue to thicken up early Saturday in advance of an approaching short wave from the west. Some light precipitation will develop later Saturday morning and continue into Saturday afternoon as the disturbance crosses the region. The precipitation will be in the form of light snow across the north with perhaps an inch or so of accumulation by late afternoon. Across central and downeast light snow will mix with rain, and even change to all rain close to the coast. Any snow accumulation there will be less than an inch. High temperatures on Saturday will be unseasonably mild, with low to mid 30s north and upper 30s to lower 40s downeast. Somewhat colder air will move in for Christmas eve night but it will still well above normal for this time of year. Expect mostly to partly cloudy skies across the north and partly cloudy to mainly clear downeast. No travel problems are expected on Christmas Day as Canadian high pressure builds toward the area from the northwest. Expect mainly sunny skies across the region with highs ranging from the low to mid 20s north and lower 30s downeast. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... Sunday night will be clear and quite cold as good radiational cooling conditions will be in place. Monday will see increasing clouds with precipitation was again overspreading the area by afternoon, as an area of low pressure tracks to our north. This system will bring another round of snow to northern areas later Monday and Monday night and a mix of snow and rain downeast. Colder air will move in behind this system for Tuesday and Tuesday night. Dry and cold conditions will return for Wednesday as another Canadian high builds in from the northwest. Another system could bring another round of snow or mixed precipitation by Thursday. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... NEAR TERM: LIFR in areas of low cloud and fog will improve to MVFR later tonight. It looks like MVFR for all terminals right into Friday morning. Conditions are expected to go VFR for KBGR and KBHB later Friday morning. MVFR cigs look to hang on across the northern terminals right into the afternoon. SHORT TERM: VFR Friday night. MVFR with possible IFR Saturday afternoon in snow north and snow/rain mix south. VFR Saturday night though Sunday night. MVFR and possible IFR once again later Monday and Monday night in snow north and snow or mix south. Outlook for Tuesday is VFR except possible MVFR conditions in isld snow showers and stratocu ceilings across the north. VFR all areas Wednesday. && .MARINE... NEAR TERM: Winds are forecast to increase this evening to 15 to 20 kt w/gusts hitting 25-30 kt. Seas will be building to a range of 4-6 ft. The wind will drop off later Fri morning as low pres pulls away. Seas look like they will stay up longer around 6 ft especially over the outer zones as a swell component remains. SHORT TERM: Winds/seas are expected to remain below small craft advisory levels Friday night and then increase to small craft advisory levels Saturday through Sunday. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...None. MARINE...Small Craft Advisory until 10 AM EST Friday for ANZ050>052. && $$ Near Term...CB/Hewitt Short Term...Duda Long Term...Duda Aviation...CB/Hewitt/Duda Marine...CB/Hewitt/Duda
Area Forecast Discussion
National Weather Service Dodge City KS
735 PM CST Thu Dec 22 2016 .UPDATE... Issued at 735 PM CST Thu Dec 22 2016 Calls to spotters indicate most of the precipitation across the SW zones is falling in liquid form (either rain or freezing rain). Snow is becoming increasingly unlikely and took out of the weather grids. Showers will move quickly with light QPF. limiting impacts. That said, HRRR continues to spread widespread light precipitation over SW Kansas overnight. Temperatures are just below freezing at most locations, and if freezing rain becomes the dominant type, a short-fused advisory may be required. UPDATE Issued at 642 PM CST Thu Dec 22 2016 Realigned pop and weather grids through tonight based on latest radar and model trends. HRRR appears to have the best grasp on reality, with a light mix reentering SW KS, and the large mass of light rain/mix across the NW TX panhandle. HRRR suggests this precip will flirt with the southern border for the next several hours, but any QPF will be light. As warm advection and strong LLJ kicks in after midnight, precipitation will trend to being more liquid, but again very light. Temperatures will hold steady or slowly rise tonight. Will monitor for any freezing rain reports, as it doesn`t take much to cause problems. Increased wind grids a few knots toward morning with the strong low level jet, and increased high temperatures a couple degrees Friday with sunshine and downslope. && .SHORT TERM...(This evening through Friday) Issued at 230 PM CST Thu Dec 22 2016 A weak disturbance moving through the area will bring a chance of precipitation this evening into the early overnight period. Precipitation looks to fall as mostly rain this afternoon with an occasional mix of snow or freezing drizzle. Freezing drizzle or snow will be possible this evening through around midnight, otherwise expect mostly cloudy skies. Precipiation chances will be confined across central and south central Kansas after midnight but this should move out of the area by sunrise tomorrow. Winds will generally be from a southerly direction through tonight as a dome of high pressure shifts eastward with a trough of low pressure setting up across eastern Colorado. Cloudiness decreases tomorrow with mostly clear skies anticipated by tomorrow evening. Winds are expected to shift to a northerly direction tomorrow as a weak cold front slides through the area. As for temperatures, lows tonight look to dip to around freezing with highs tomorrow reaching to the low 50s to around 50 degrees. .LONG TERM...(Friday night through Thursday) Issued at 230 PM CST Thu Dec 22 2016 Partly cloudy skies and dry conditions are expected Friday night through Saturday as an upper level ridge moves over the Rockies and Plains. Meanwhile, a strong upper level trough/low will dig into the Western United States Saturday, then into the Rockies Sunday. This system then pushes northeastward into the Northern Plains Sunday night into Monday morning. Cloudiness will increase Saturday night as this system approaches with cloudy skies anticipated by sunrise Sunday. As of now, far western Kansas looks to be dry slotted with this system with decreasing clouds from west to east as we progress through the day Sunday. Scattered showers and embedded thunderstorms will be possible across central and south central Kansas Sunday morning then push eastward out of the CWA Sunday afternoon. A dry weather pattern is progged by the models during the beginning of next week with the next system moving into the area mid to late week. As for temperatures, highs will generally range from the upper 40s to upper 50s Saturday and Sunday then dip into the 40s Sunday through the mid part of next week. Lows in the low to mid 20s are expected Friday night then only dip into the 30s to lower 40s Saturday morning ahead of the next system. Lows in the teens to 20s are anticipated through the remainder of the extended forecast. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 500 PM CST Thu Dec 22 2016 Weakening shortwave will continue to produce scattered -SHRASN through this evening. NAM model suggests GCK northward for this light precipitation, while HRRR suggests a more southerly solution. With this dichotomy, just left VCSH in the TAFs for a few hours this evening. Any precipitation will be light with impacts on aviation flight categories minimal. MVFR cigs will gradually improve overnight as lift from shortwave wanes. After 06z, strong LLWS expected with a strong 850 mb LLJ progged of 50-60 kts. This will also keep nocturnal winds gusty and elevated overnight, gusting as high as 30 kts at DDC. After 15z Fri, winds will weaken and veer NW under a clearing sky. && .PRELIMINARY POINT TEMPS/POPS... DDC 32 56 23 51 / 60 10 0 0 GCK 34 52 22 53 / 50 0 0 0 EHA 29 55 29 57 / 50 10 0 0 LBL 31 56 25 57 / 60 10 0 0 HYS 33 50 21 49 / 40 10 0 0 P28 32 55 26 52 / 30 20 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Turner SHORT TERM...Hovorka_42 LONG TERM...Hovorka_42 AVIATION...Turner
Area Forecast Discussion
National Weather Service Wilmington OH
1000 PM EST Thu Dec 22 2016 .SYNOPSIS... Surface high pressure will build east across the region tonight into Friday. Most of Friday looks dry with rain chances increasing Friday night with the approach of the next frontal system. Rain chances will diminish Saturday afternoon after the passage of the frontal system. A chance of light rain will return with warm temperatures on Christmas day. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A persistent stratocumulus shield over eastern Ohio has finally just about cleared through the ILN forecast area, with just some sections of the far eastern counties (Licking/Fairfield/Hocking) still affected. Once these clouds are gone, increasing cirrostratus (20kft-25kft) will still remain in place. This should help limit the potential for significant cooling overnight, even as winds are becoming fairly calm across the region. Not surprising to see some slight drops in visibility, but HRRR signals have been fairly consistent in suggesting that any potential for dense fog will remain northwest of the ILN forecast area. Though the clouds over the east have temporarily kept temperatures higher than expected, overall the current forecast trends are in line with observations, and thus no changes were made to the min temp forecast. Previous discussion > Zonal mid level flow with surface high pressure building east across the region overnight. Latest satl imagery shows post frontal low clouds eroding across ILN/s western counties. This trend will continue with low clouds diminishing through the evening, resulting in mostly clear skies for a period late this evening. Moisture in the form of high and mid level clouds will increase late tonight. Lows to range from the lower 20s nw to the mid 20s se. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... In zonal flow pattern surface high pressure to slide east of the region Friday. Next progressive mid level shortwave to track through the Great Lakes Friday night and Saturday. Ahead of this shortwave, favorable isentropic lift develops by Friday evening. Expect most of the day to remain dry and have a slight chance west late in the afternoon. This chance increases to categorical Friday night across most of the FA as 50 kt low level jet and associated lift comes into play. High temperatures on Friday to range from the upper 30s nw to the mid 40s se. In strong waa regime, under the influence of a 50 kt southerly low level jet expect non- diurnal temperature trace Friday night. With rising temperatures Friday night, have mainly rain across ILN/s FA. Given favorable lift have continued categorical pops early Saturday across the southeast ahead of sfc cold front. Behind the shortwave expect a temporary break in the precipitation due to weak subsidence. The weak cold front will stall across the far southern parts of the CWA. Expect considerable cloudiness Saturday with highs from the upper 30s northwest to the upper 40s southeast. Chance pops for rain to continue mainly across the southwest Saturday night closer to the frontal boundary as ridge builds across the eastern CONUS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Upper ridge will be in place across the eastern CONUS to start the period. For Sunday, a surface low is forecast to ride up the west flank of the upper ridge to the northern plains, while a warm front pushes across the ILN area. This will bring a chance of showers which will diminish by Sunday night as the front lifts north. A cold front will follow on Monday, with showers likely. High pressure and drier conditions are expected Tuesday. Another low and frontal system may impact the region with more showers Wednesday into Thursday, with snow possibly mixing in at night. Above normal geopotential heights combined with warm advection on a southerly low level flow will produce much above normal temperatures Sunday and Monday, when highs will reach the 50s and 60s. Closer to normal highs around 40 are indicated for Tuesday through Thursday under cold advection at the surface and aloft. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... The edge of the borderline VFR/MVFR stratocumulus clouds is now moving east through the region, and should clear the ILN/CMH/LCK TAF sites in the next hour or two. After this occurs, VFR conditions are expected through the overnight, outside of some possible MVFR fog at LUK. Tomorrow, winds will very gradually increase in strength from the SE, as high clouds begin to thicken and lower. By late afternoon, mid-level clouds are likely to be in place, with rain showers likely holding off until evening. Once the rain showers move in, MVFR (and eventually IFR) conditions will be expected. OUTLOOK...MVFR/IFR ceilings and visibilities are possible at times from Friday night into Monday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...AR NEAR TERM...Hatzos/AR SHORT TERM...AR LONG TERM...Coniglio AVIATION...Hatzos
Area Forecast Discussion
National Weather Service North Platte NE
934 PM CST Thu Dec 22 2016 .UPDATE... Issued at 934 PM CST Thu Dec 22 2016 Just hoisted a winter weather advisory for portions of southwestern and central Nebraska. The HRRR and 00Z NAM solution now has a band of light precipitation across southwestern into portions of central Nebraska late tonight into Friday morning. Temperatures will hover in the upper 20s to around freezing during the greatest threat for precipitation. This will also hit right at commute time in the morning so timing figured into the issuance of the advisory. By late morning, temps will rise back into the mid to upper 30s, ending the freezing precipitation threat. Turning to the main storm this weekend, with the latest NAM, beginning to become more concerned about a freezing rain threat over northern Nebraska late Saturday night into Christmas morning. Like last night`s model runs, the greatest threat for accumulating snow continues to be over the northeastern panhandle and northwestern sandhills. && .SHORT TERM...(This evening through Friday) Issued at 323 PM CST Thu Dec 22 2016 The latest near term projections continue to indicate the potential for mixed precipitation overnight tonight across southwest Nebraska and northeast through our north central zones. The models suggest the closed low currently over northern Baja will rapidly advance east to southern Colorado and open to a wave. The main PV anomaly with the wave is then shown to advance northeast across Kansas Friday reaching the upper Mississippi River Valley late in the afternoon. As broad large scale forcing increases ahead of the system, solid moisture will advect northward over the High Plains and reach the CWA as early as this evening. Soundings across southwest Nebraska northeast through north central Nebraska reveal rapid saturation both in the lower levels and within the DGZ. As the precipitation expands northeast from southwest Nebraska we anticipate a change over to a mix or even all snow. The previous shift eluded to the loss of saturation in the DGZ as dry air invades the upper levels, leading to drizzle concerns. Bufkit soundings still hint at the possibility, so will continue a slight chance mention in the grids, but agree with the previous shift that the potential is low and if fzdz is realized, then accumulations would be a trace or less. The Ptype forecast is somewhat questionable given marginal thermal profiles for a change over to snow and the timing of the arrival of the dry air aloft. We decided to keep Ptypes simple as possible, only focusing on the potential impacts of rain changing to snow and if freezing drizzle is realized. As for snow amounts, qpf with the system is light, thus most locations will only see a dusting or possibly as much as a tenth of an inch. The rapid progression of the system will allow for transitory shortwave ridging to build into the high plains late Friday. Precipitation will end from southwest to northeast through the day. Temperatures will largely return above average for most locations. Highs in the 30s are likely for northern Nebraska, but mid to upper 40s are likely across southwest Nebraska. Elsewhere lower 40s are forecast. .LONG TERM...(Friday night through Thursday) Issued at 323 PM CST Thu Dec 22 2016 Friday night through Thursday...a storm is over the Gulf of Alaska is forecast by all models to lift through Nebraska Sunday. The sfc low triple point moves from Swrn Neb to Ncntl Neb Sunday afternoon. Areas along and east of the triple could see an isolated thunderstorms...maybe more...leading to scattered thunderstorm coverage. A locally developed multimodel severe weather ensemble procedure has trended west favoring thunderstorms across Scntl Neb Sunday which could easily lift north and northwest through the forecast area. This convection would feed into a deformation zone forecast to develop across Northwest Nebraska Sunday afternoon. It is uncertain how far south arctic air will move in ahead of this system. A lead short wave will move through Srn Canada Friday and this will tug arctic air south into the Dakotas Saturday. There may be enough cooling at night for periods of freezing rain or drizzle Saturday night. This cold air should quickly erode as south winds increase Sunday morning leading to all rain. Once the upper low lifts north of Nebraska Sunday afternoon...a rain snow line will move rapidly east through Western and North Central Nebraska. All models indicate a mix of freezing rain and sleet before change over to snow. Snow chances decrease Sunday night. The wind forecast is very modest increasing west and northwest winds to 25 to 30 mph late Sunday afternoon. The model consensus indicates 35 mph winds at 00z Sunday evening using 500m AGL winds mixed down to the sfc. There is a brief period of 60-70kt 700mb winds which will pass over the region late Sunday afternoon and evening. This is a fast moving storm moving at 30 mph so these strong winds may not mix down. The snow forecast is similar to WPC with close to 6 inches across a small portion of Northern Sheridan County...Pine Ridge. The ECM and NAM are the srn solns with the Storm track while the GFS and ensemble are farther north basically sparing the forecast area of significant snow. The SREF was in the middle of the model cluster. Later forecasts may trend north or south as the storm is still 3 days out. The storm will pull arctic air into the region Monday morning but the upper flow is so progressive that temperatures will moderate Tuesday. Another weak cold front will move through Thursday. The forecast is dry Monday through Thursday. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 604 PM CST Thu Dec 22 2016 Ceilings will continue to fall this evening as an upper level disturbance lifts northeast across southwestern into northeastern Nebraska. Light freezing drizzle will be possible at the KLBF terminal toward 12z Friday Morning. Ceilings may drop as low as 1000 FT AGL as well. Ceilings will fall tonight at the KVTN terminal, but should remain VFR and no freezing drizzle is expected ATTM. Skies are expected to clear out Friday afternoon. && .LBF WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 2 AM CST /1 AM MST/ to 10 AM CST /9 AM MST/ Friday for NEZ038-059-069>071. && $$ UPDATE...Buttler SHORT TERM...Jacobs LONG TERM...CDC AVIATION...Buttler