Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/14/18

Area Forecast Discussion
National Weather Service Burlington VT
1014 PM EDT Sat Oct 13 2018 .SYNOPSIS... A fall like pattern will prevail across the North Country this week with moderate swings in daily temperatures and chances for precipitation every couple of days. Areas of frost can be expected tonight, especially away from the warmer Lake Champlain lake waters. Overall, temperatures will trend on the cooler side of normal with highs mid 40s to mid 50s, except only in the 30s and 40s on Thursday. Some light snow accumulation is possible in the mountains, especially toward midweek. && .NEAR TERM /THROUGH SUNDAY NIGHT/... As of 1014 PM EDT Saturday...Frost and freeze headlines continue for tonight across portions of our forecast area. Overall forecast in good shape. Areal coverage of clouds continues to decrease and mostly clear skies should develop most areas after midnight. Winds continue to taper off and with increased radiational cooling...frost and freeze conditions should develop toward morning...which again going forecast has covered well. Previous Discussion... Forecast challenge tonight is areal coverage of clouds and potential impacts on temperatures. The fall season has arrived where cloud forecasting is difficult and greatly influence how low temps can fall. The synoptic scale shows mid/upper level trof across our fa with building axis of subsidence/dry air aloft based on water vapor trends. However, vis satellite and upstream trends show very few breaks in the overcast, as sfc high pres is centered to our south across the Ohio Valley. This creates a west to northwest flow from the sfc thru 800mb across the warmer Great Lakes and as cooler air flows over the warmer waters low level moisture is enhanced and results in more clouds downwind over the dacks and mountains of VT. The RAP soundings show this shallow layer of rh btwn 925mb and 800mb thru 04z, especially in the mountains, so have continued to linger clouds later into the evening hours. This will result in a slower rate of fall initially for hourly temps, but thinking values should cool enough toward sunrise for areas of frost to develop away from Lake Champlain. Have lows mainly in the upper 20s cooler mountain valleys to lower 40s near Lake Champlain. These values could be 2 to 5 degrees warmer if more clouds linger longer than forecast with less areas of frost. On Sunday, as 925mb to 850mb winds shift to the southwest at 10 to 20 knots expect a ribbon of low level Lake Ontario enhanced moisture to swing across the dacks and parts of the SLV. A spot rain or snow shower is possible, but depth of moisture is minimal so pops are slight chance at best. Meanwhile, additional 850 to 500mb rh increases aft 18z on Sunday associated with developing waa ahead of our next system. Expect mid/upper level clouds to increase during the aftn hours, which will impact temps. Progged 850mb temps near 0c would support upper 50s valleys, but given expect partly sunny skies have lowered highs back into the mid/upper 40s mountain towns to l/m 50s warmer valleys. Quiet weather continues on Sunday night with low level waa continuing ahead of our next system. Winds should decouple in the deeper valley, especially east of the Green Mountains, allowing temps to drop back into the l/m 30s to l/m 40s cpv/slv. Latest guidance has delayed arrival of precip by 3 to 6 hours so have kept overnight period dry with increasing clouds. && .SHORT TERM /MONDAY THROUGH MONDAY NIGHT/... As of 257 PM EDT Saturday...Overall little change from the previous forecasters thinking for the period with the main player being low pressure tracking northeast through the Ottawa Valley. Monday morning starts dry as the attending warm front approaches from the southwest, with somewhat scattered showers moving in during the mid- morning to early afternoon hours along the boundary. Post frontal passage there perhaps could be a brief break in rainfall before the trailing cold front swings through the area after sunset with more widespread light rain expected through the first half of Monday night. The presence of a modest 850mb jet around 40kts will keep the best chances for showers across the higher terrain, with significant downsloping likely in the Champlain Valley. On the flip side, behind the cold front, that same jet may help to linger showers across the orographic upslope areas, which would likely mix with and/or change to snow at highest elevations, but it appears the flow becomes highly unblocked so no significant accumulations are anticipated. Temps for the period remain on the chilly side of normal with highs mainly in the low/mid 50s, and lows ranging through the 30s to locally lower 40s in the Champlain Valley close to the lake shoreline. && .LONG TERM /TUESDAY THROUGH SATURDAY/... As of 257 PM EDT Saturday...Behind the aforementioned frontal passage, Tuesday should be mainly dry but unseasonably cold as a weak ridge of surface high pressure builds into the region with highs only in the 40s. Late Tuesday night a cold front approaches which will bring the chance for some lake effect rain/snow showers across the southwest Adirondacks early Wednesday morning, and then more widespread precipitation during the day Wednesday. Highs Wednesday will only be in the upper 30s to mid 40s with snow levels lowering through the day to near the valley floor by sunset. As such, morning rain showers will mix with and change to snow by early afternoon across the Adirondacks, and then during the remainder of the afternoon over central and northern Vermont, lingering into Wednesday night. While early in the game to nail down the finer details, the potential exists for total snow accumulations by Thursday morning of 1-3" above 1500` and a dusting to an inch from 500-1500`. In addition, winds Wednesday will be quite brisk with gusts likely in the 20-30 mph range, which will make for some chilly wind chills. Surface high pressure builds back in the region for Thursday with dry conditions ensuing. Temps remain quite cold for mid-October with lows Wednesday night mainly in the 20s, and highs Thursday only in the 30s. Depending on how much snow falls on the higher elevations, and the amount of leaves left on the trees, we could have some nice snowliage Thursday afternoon/evening with some breaks of sunshine possible. Thursday night looks almost as cold as the previous night with high pressure just beginning to shift east of the region, but by Friday some moderation in temps is expected as southwest flow develops between the departing high and an approaching trough/low to our west. Another cold front will bring the chance for precipitation Friday night through Saturday. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Through 00Z Monday...VFR conditions are expected through the period. Scattered-broken clouds will exist through 04z around the 5000 foot level then decrease quickly in areal coverage. No precipitation is expected and thus visibilities will remain in the VFR category through the period. Winds will be from the northwest at 5 to 10 knots early in the period...then becoming light and variable after 04z. Winds will become southerly after 12z...but remain at speeds of 10 knots or less. Outlook... Sunday Night: VFR. NO SIG WX. Monday: Mainly MVFR, with areas VFR possible. Chance SHRA. Monday Night: Mainly VFR, with areas MVFR possible. Chance SHRA. Tuesday: VFR. NO SIG WX. Tuesday Night: VFR. Chance SHRA. Wednesday: Mainly VFR, with areas MVFR and IFR possible. Likely SHRA, Likely SHSN. Wednesday Night: VFR. Slight chance SHSN. Thursday: VFR. NO SIG WX. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...Frost Advisory until 8 AM EDT Sunday for VTZ002-005-009-011. Freeze Warning until 8 AM EDT Sunday for VTZ006-008-010-012- 016>019. NY...Frost Advisory until 8 AM EDT Sunday for NYZ026>028-035-087. && $$ SYNOPSIS...Taber NEAR TERM...Evenson/Taber SHORT TERM...Lahiff LONG TERM...Lahiff AVIATION...Evenson/Taber
Area Forecast Discussion...UPDATED
National Weather Service Cheyenne WY
612 PM MDT Sat Oct 13 2018 .SHORT TERM...(This evening through Sunday night) Issued at 315 PM MDT Sat Oct 13 2018 Forecast tonight through the rest of the weekend remains on track. An unusually cold outbreak is expected with very cold air already starting to work its way southward across the forecast area. Surface cold front has moved into the Colorado plains this afternoon and is stalled along the Laramie Range. Temperatures have fallen into the 40s with Cheyenne`s temperatures now at 50 degrees after a high of 60 earlier. Expect this front to continue moving southwest into the mountains through tonight. Recent webcams along and east of I-25 show that any rainfall has switched to snow with snow reported in Douglas. This trend will continue into this evening with a brief period of light rain or sprinkles at the onset of the precip before a quick change over to snow. Dynamic forcing is still in place with the 12z models showing similar solutions compared to 12 hours ago. The 12z ECMWF is a bit more aggressive across far southeast Wyoming and far southwest Nebraska, so may need to extend the Winter Storm Warning in Banner, Kimball, and maybe even Scottsbluff county. Most ensemble members are more aggressive with precip amounts as well, so will need to keep an eye on snowfall rates through this evening. On the other hand, The HRRR and the NAM show an area of drier air near the surface at the onset of this event, mainly impacting areas between Laramie, Chugwater, and Cheyenne. This may cut snow totals locally, but will keep previous snow totals as is due to the threat of heavy snow and snowfall rates between 1 to 2 inches per hour for a few hours. Extended the Winter Weather Advisory into the rest of western Nebraska in addition to Niobrara county. 12z model runs continue the trend of showing higher QPF and snowfall amounts from Lusk southeast towards Chadron and Alliance through late this evening, so increased total snow accumulations. With rapid freezing this evening, expect any slush or water on area roads from melted snow to freeze over night and become a hazard through early Sunday morning. Overnight temperatures in the teens to low 20s are expected with wind chills in the single digits above and below zero. Moderate to heavy snowfall should come to an end after midnight with light snow and flurry activity expected until early to mid morning Sunday. Very cold temperatures for this early in the season will be the main concern late Sunday and especially Sunday night. Models show a 1035 to 1040 mb surface high settling over southeast Wyoming, especially west of I-25 late Sunday through Sunday night. With little or no wind, clearing skies, and a surface snow pack across much of the area, excellent radiational cooling is expected. Most of the area will likely have record low temperatures, and some locations may break their record low by 10 to 15 degrees. Continued to lower temperatures with lows mainly in the single digits across the region, including western Nebraska. Expect some readings down to -10, such as the Laramie Valley and other sheltered valleys with a decent snowpack by early Monday morning. .LONG TERM...(Monday through Friday) The extended forecast period should be rather quiet, with no major storm systems expected to impact the region. The main concern will be temperatures, especially on Monday/Tuesday w/ the potential for deep snow pack from the preceding winter storm. We trended several degrees below consensus guidance on Monday, but the predictability is low with uncertainty in the exact placement of any heavier snow bands. Otherwise, generally dry conditions prevail w/the exception of occasional mountain snow showers as the GFS & ECMWF show a weak cut off over the 4 Corners mid-to-late week. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 602 PM MDT Sat Oct 13 2018 Very poor flying conditions expected across the entire region this evening and through the overnight with moderate to heavy snow at times with reduced visibilities down to 1/4SM to 3SM and at least IFR if not lower ceilings. Snow is already ongoing from KDGW southward to just north of KCYS and eastward into KBFF. Visibilities and ceilings will fall quickly over the next several hours. +SN will occur at times from KLAR to KCYS and KSNY overnight that could bring visibilities down to 1/4SM at times. Flying should be avoided at all costs from 02Z through 12Z Sunday morning. Snow will become lighter and taper off through mid- morning hours Sunday as IFR and MVFR ceilings persist. VFR conditions will finally occur by mid to late afternoon across the region as the system passes east. Winds will be north at 15 knots with gusts upwards of 30 knots through the overnight. Gustiness will reduce slightly by 12Z Sunday but sustained winds will remain 10-20 knots through entire period from the north and northeast. && .FIRE WEATHER... Issued at 224 PM MDT Sat Oct 13 2018 No Fire Weather concerns through the weekend and into next week. A strong cold front will push into Colorado by this evening allowing much colder air to push into the area in addition to widespread snowfall. Very cold to bitter cold temperatures are forecast through Monday morning. Milder temperatures and dry weather are expected Tuesday through Friday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory until 9 AM MDT Sunday for WYZ101>105-107- 108-110-114-115-119. Winter Storm Warning until 9 AM MDT Sunday for WYZ106-116>118. NE...Winter Weather Advisory until 9 AM MDT Sunday for NEZ002-003- 019>021-054-055-095-096. && $$ SHORT TERM...TJT LONG TERM...CLH AVIATION...JSA FIRE WEATHER...TJT
Area Forecast Discussion
National Weather Service Goodland KS
826 PM MDT Sat Oct 13 2018 .UPDATE... Issued at 825 PM MDT Sat Oct 13 2018 Hard Freeze Warning: With record or near-record low temperatures in the upper teens to mid 20s expected Monday morning, a Hard Freeze Warning (valid 03-14Z Monday) has been issued for Cheyenne county in Colorado and Graham, Gove, Logan, Wallace, Greeley, and Wichita counties in Kansas -- the counties that have not experienced a hard freeze yet. Winter Weather Advisory: Significant uncertainty persists with regard to precipitation type/accumulation late tonight and Sunday, particularly in northwest Kansas where the bulk of precipitation may fall as rain associated with elevated convection within the first 3-4 hours after the cold frontal passage -- before thermal profiles become supportive of frozen precipitation (excluding hail). Furthermore, HRRR and NAM-NEST simulated reflectivity forecasts suggest that precipitation may remain convective in nature during the day Sunday. If this is the case, precipitation type may be driven by the precipitation itself. In other words, snow may predominate where radar echoes are deeper and saturation extends to at least the -12 to -15C isotherm height and DZ|FZDZ may predominate where echoes are shallower (FZDZ if sfc wetbulb < 32F or DZ if sfc wetbulb >= 32F). In such a setup, precipitation type/accumulations cannot be ascertained with much certainty. As a result, the Winter Weather Advisory has been updated to reflect snow accumulations ranging from a dusting to 3" and ice accumulations ranging from a trace to 0.10". If later surface observations and remote-sensing data suggest that an extended period of FZDZ will be possible in eastern CO and southwest Nebraska, then the Winter Weather Advisory may need to be expanded to include Kit Carson and Yuma counties in CO and Dundy, Hitchcock and Red Willow counties in NE. && .SHORT TERM...(This evening through Sunday night) Issued at 346 PM MDT Sat Oct 13 2018 Main concern will be upcoming winter storm tonight through Sunday night. Due to model differences in timing of colder air, thermal profile, and precipitation placement and timing, there is now a high degree of uncertainty with this forecast. First the models are wanting to produce convective precipitation in advance of the incoming front and upper shortwave trough. However as the day has gone on, they have been cutting back on that. To account for the above and neighboring offices different interpretations or models they chose, kept a low chance for precipitation in to begin the period since I think the convective precipitation is overdone. Going by when the upper jet and strong incoming shortwave trough are coming, I am thinking the bulk of the precipitation is not going to start until later this evening maybe even until the overnight hours. Then comes the question of phase. Normally the Nam which starts things out colder is actually warmer and about 3 hours slower than the Gfs is putting ice in the column and starting snow. The Nam more-so than the Gfs keeps a warm layer above the freezing/subfreezing low levels. Consequently the thinking was changed to the possibility of a more mixed precipitation occurring before the onset of the snow. So as a result of the change in thinking, so snow amounts were lowered due to a later changeover to snow. So converted the winter storm watch to a winter weather advisory. I also kept the start time the same since we will be having a freezing precipitation that will cause slick roads. Also to compound the precipitation problem, fog will develop and will also reduce the visibility before changeover to snow. The winds will also be strong enough to cause any blowing of the snow. However, the caveat to all this is if there will be more convection than I expect and could cool the column and cause the snow to start earlier. Stay tuned. I will not be surprised at what happens. .LONG TERM...(Monday through Saturday) Issued at 229 PM MDT Sat Oct 13 2018 A positively tilted trough extends from the Midwest to the far southwestern U.S. An upper level low cuts off from the trough and sits over the southwestern U.S. Monday night. The trough then moves off to the northeast and is immediately replaced by another trough over the Midwest Tuesday. With the trough to the northeast and cutoff low to the southwest, the Tri-State region gets stuck in between. The cutoff low over the southwest U.S. rejoins the main upper level flow Wednesday night creating a trough. This weakens the incoming ridge moving southeast from the Pacific northwest. The trough begins to enter the area Thursday with the axis over the Tri- State region by Friday night. This pattern makes it hard for a ridge to stay intact as it moves east across the central U.S. Temperatures are expected to warm up starting Tuesday into the 50s and 60s through the week. Lows in the 30s and 40s are expected through most of the week. Dry and mostly sunny conditions are anticipated Monday afternoon through Saturday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 630 PM MDT Sat Oct 13 2018 A cold front will progress across the Tri-State area late this evening (~03Z at MCK and ~06Z at GLD). In the wake of the front, winds will abruptly shift to the N/NE and increase to 25 kt gusting up to 35 kt and ceilings will quickly deteriorate to MVFR/IFR. Breezy N/NNE winds will persist through the remainder of the TAF period, though gusts are not expected to exceed 30 kt after ~18Z Sun. MVFR/IFR ceilings are expected to persist through the remainder of the TAF period. Significant uncertainty persists with regard to precipitation type late tonight and Sunday. At this time, expect precipitation in the form of rain through ~09Z, followed by an increasing potential for freezing drizzle or snow between 09-12Z. Alternating periods of freezing drizzle and/or snow will be possible from 12Z through the remainder of the TAF period. && .CLIMATE... Issued at 630 PM MDT Sat Oct 13 2018 Monday morning could bring record cold to the Central High Plains. To put Monday`s potentially record-breaking cold temperatures into perspective, below is a comparison of some weather stations in the region, their lowest recorded temperature for any October 15th, and their forecasted low temperatures at this time for this coming Monday. The year of the record set is in the parentheses next to the current record value. The beginning of the period of record for each station is listed in parentheses next to the station name, with each period of record lasting through the present. Station..........Minimum Recorded Temp 10/15...Forecast Low 10/15/18 McCook, NE (1896)...............25 (1943).................21* McCook, NE Airport (1967).......26 (1974).................21* Colby, KS 1SW (1957)............20 (1966).................20* Goodland, KS (1895).............16 (1966).................19 Hill City, KS (1907)............23 (1943).................23* Oakley, KS 4W (1920)............23 (1943).................20* Oberlin, KS (1913)..............20 (1943).................21 Sharon Springs, KS (1893).......22 (1952).................19* Burlington, CO (1903)...........20 (1905).................18* Burlington, CO Airport (1997)...24 (2002).................18* Cheyenne Wells, CO (1897).......21 (1943).................18* Flagler, CO 1S (1919)...........13 (1966).................15 Kit Carson, CO (1939)...........17 (1943).................20 Wray, CO (1893).................19 (1976).................19* Yuma, CO (1939).................14 (1966).................17 *These values would set or tie records if they verify Monday. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...Hard Freeze Warning from 9 PM MDT /10 PM CDT/ Sunday to 8 AM MDT /9 AM CDT/ Monday for KSZ016-027>029-041-042. Winter Weather Advisory from midnight MDT /1 AM CDT/ tonight to midnight MDT /1 AM CDT/ Sunday night for KSZ002>004-013>016- 027>029-041-042. CO...Hard Freeze Warning from 9 PM Sunday to 8 AM MDT Monday for COZ092. Winter Weather Advisory from midnight tonight to midnight MDT Sunday night for COZ092. NE...NONE. && $$ UPDATE...VINCENT SHORT TERM...BULLER LONG TERM...NEWMAN AVIATION...VINCENT CLIMATE...PATTON
Area Forecast Discussion
National Weather Service Lincoln IL
837 PM CDT Sat Oct 13 2018 .UPDATE... Issued at 837 PM CDT Sat Oct 13 2018 Light rain associated with a shortwave over Arkansas, has spread north into southern Illinois this evening, and will continue northeast mainly impacting areas along and south of the I-70 corridor overnight. Farther northwest, a thicker mid level cloud deck already affecting west central IL, will overspread most of the CWA tonight. This will help to keep temperatures several degrees warmer than last night, mainly near 40 along and north of I-74, to the mid 40s south of I-70. && .SHORT TERM...(This evening through Sunday) ISSUED AT 327 PM CDT Sat Oct 13 2018 Short-wave trough associated with former Pacific Hurricane Sergio is tracking through the Southern Plains this afternoon...triggering powerful thunderstorms across east Texas. Further north, clouds and light rain associated with this feature are spreading into the Ozarks. As the wave continues E/NE toward the Tennessee River Valley, showers will gradually lift into southeast Illinois later this evening into the overnight hours. Considerable model spread exists concerning the exact northward extent of the precip...with the 12z NAM being the furthest north near the I-72 corridor, while the GFS keeps the rain south of I-70. 18z HRRR looks similar to the GFS. As a result, have focused high chance to likely PoPs south of I-70...with slight chance as far north as a Danville to Taylorville line. Overnight low temperatures will be warmer than last night with readings ranging from the upper 30s far north around Lacon to the middle 40s far southeast at Lawrenceville. The light rain will continue across the S/SE KILX CWA through Sunday morning before shifting eastward into the Ohio River Valley by midday. Meanwhile, a vigorous northern-stream wave digging into the Upper Midwest will begin pushing a cold front toward Illinois late in the day. Model guidance keeps most of the precip along/west of the Mississippi River through the afternoon, but have introduced low chance PoPs west of the Illinois River after 21z/4pm in case a few showers spread that far eastward before sunset. High temperatures will be in the lower to middle 50s. .LONG TERM...(Sunday night through Saturday) ISSUED AT 327 PM CDT Sat Oct 13 2018 Cold front pushes into Illinois Sunday night, bringing high chance to likely PoPs to the entire area. Best rain chances will be during the evening, with chances decreasing from west to east after midnight as the front passes. While low temperatures will drop into the middle 30s across the Illinois River Valley, am not expecting any change over to deep-layer moisture quickly shifts eastward and thermal profiles suggest a loss of ice crystals aloft. Light rain will linger across the E/SE through Monday afternoon before exiting to the E/SE by early evening. As has been advertised for the past several days, high pressure is expected to bring clearing skies, diminishing winds, and the coldest readings of the fall season Monday night. Latest guidance is showing overnight lows dropping into the lower 30s across all but the far SE. Think this looks reasonable as winds are not progged to go completely calm and should mix the boundary layer sufficiently to prevent maximum radiational cooling. Even still, with lows at or near freezing...frost and/or freeze headlines will eventually be required for Monday night. After that, dry and cool weather will prevail through Thursday before the next weather system brings a chance for rain by Friday. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 647 PM CDT Sat Oct 13 2018 Band of MVFR ceilings persists from the Mississippi River to just west of the Illinois River early this evening. HRRR insists these low clouds will stay in place through the evening, then develop/spread eastward overnight. Based on HRRR timing, have introduced MVFR ceilings by 07z at KPIA, 09z at KSPI, then 11z further northeast at KCMI. Once the clouds return, it appears they will stay in place for the remainder of the 00z TAF period as per NAM forecast soundings. Light rain associated with a disturbance approaching from the southwest will remain south of the terminals overnight into Sunday morning. Winds will be light through the entire period. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...25 SHORT TERM...Barnes LONG TERM...Barnes AVIATION...Barnes