Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/23/22

National Weather Service Hastings NE
952 PM CST Tue Nov 22 2022 ...Short Term Update... .UPDATE... Issued at 951 PM CST Tue Nov 22 2022 -- Regarding at least limited (in area) fog/dense fog potential Wed AM...especially between 7-10 AM: - The basics: By far the main change to the very short term forecast since the main afternoon issuance has been the addition of "patchy" to "areas" of fog to parts of our southeastern coverage area (CWA) for Wed AM...perhaps affecting the AM commute. Given that high-res models such as HRRR continue hinting that at least some potential exists for localized dense fog (reducing visibility to 1/4 mile or less), have introduced this mention to our Hazardous Weather Outlook (HWOGID) to heighten awareness a bit. This fog/dense fog potential would mainly impact areas near/east of Hwy 281 in our KS zones along with Nebraska areas mainly south of a Geneva-Blue Hill line. - More details: Concern is gradually increasing that at least a small portion of our CWA could deal with a round of at least brief fog/dense fog on Wed AM...particularly between 7-10 AM. There is a pretty decent low level moisture disparity at this time within our CWA, noted by dewpoints of 14 at Hastings...versus 30 at Hebron/34 at Concordia KS. As temps continue to cool overnight and breezes remain light, enhanced relative humidity along/near this weak boundary ("moisture front" if you will) could support at least a narrow zone of fog/dense fog. Leaning pretty heavily on HRRR/SREF visibility progs, any potential fog should be mainly confined to the southeast 1/4 of our CWA ("safely" southeast of the Tri Cities), and mainly be a 7-10 AM issue. Do not have enough forecast confidence in coverage/duration of truly dense fog to hoist a formal Advisory at this time, but enough potential exists for introduction to our HWO. This is not a "slam dunk" dense fog setup by any means, as for one thing, increasing high level cirrus clouds overnight into Wed AM could hinder fog development. At the very least, something upcoming overnight/day shifts will need to monitor. && .DISCUSSION...(This evening through Tuesday) Issued at 314 PM CST Tue Nov 22 2022 Key Messages: * Possible drizzle Wednesday night into early Thursday morning southeast of the Tri-Cities. * Thanksgiving will likely be the coolest day of the week and rather breezy, but highs should still be in the 40s. * Next storm system should pass to our southeast on Saturday, but there could be a little light rain in our far southeastern counties. * Another storm system on Tuesday November 29th could bring wintry precipitation to the area, but low confidence on storm track this far out. Rest of Today... Get outside and enjoy what remains of the afternoon as it`s the nicest day of the upcoming week with most locations hovering around 60 degrees at 3 PM. The airmass is dry and thus it will quickly cool down this evening once the sun gets low and eventually sets. Wednesday into Wednesday night... Forecast models indicate increasing clouds and especially low clouds by late day into Wednesday night particularly across our southeastern zones. The 18Z NAM is probably the most aggressive with a drizzle signature in its soundings and QPF field, but probably too aggressive. Temperatures aloft are too warm for snow and all of the moisture is in the low levels generally from around and below 850 MB. Temperatures might actually warm towards Thursday/Thanksgiving morning. So if any precipitation falls it will be either drizzle or freezing drizzle, but believe surface temperatures should climb to just above freezing if drizzle starts to fall. Therefore, drizzle is the most likely precipitation type Wednesday night into early Thursday morning. Thanksgiving... It`s a case of bad frontal timing that will lead to a rather unpleasant Thanksgiving day with cooler air moving in along with blustery northwest winds gusting 20-25 MPH behind a late Wednesday night/early Thursday morning cold front. Forecast model temperature spread is rather low allowing for high confidence in highs being stuck in the 40s for Thanksgiving. Friday and Saturday... After the cool down on Thanksgiving Day, model ensembles indicate that Friday and Saturday should be the best two days of the remaining weekend, but not as warm as we have been. At this point it appears we will likely be in the lower 50s, but some ensemble members keep us in the upper 40s. One thing to watch will be a closed upper low that will track across the southern plains. It could swing just far enough north under more northerly model solutions to bring some light rain to our far southeastern counties on Saturday. Sunday through Tuesday... We`ll be between storm systems on Sunday and Monday, with the next storm system currently expected to enter the plains by around Tuesday, but the track is rather uncertain being 7 days out. Will really need to keep an eye on Tuesday as wintry precipitation could be possible across portions of our area depending on the storm track. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Thursday) Issued at 611 PM CST Tue Nov 22 2022 -- General overview (including winds): Very high confidence in VFR ceiling/visibility through at least the vast majority of the period (only some high level clouds), and very high confidence in precipitation-free conditions throughout. The only "catch" is a very outside chance that a possible area of fog and/or very low stratus could try flirting with especially KGRI for a few hours Wed AM (more on this below). As for winds, no big issues to speak of. These next 16 hours or so will see speeds average mainly near-to-under 5KT, with direction eventually becoming a bit more established from the south late tonight into Wed AM. Around and especially after 16Z, southerly speeds will pick up modestly, but still only average around sustained 10KT (perhaps some few gusts to around 15KT). - Slight uncertainty/concern with ceiling/visibility: Particularly between 12-17Z, various models/guidance are suggestive that the extreme north-northwest edges of an area of fog and/or very low stratus could advance within perhaps as little as 25-30 miles of mainly KGRI (KEAR currently appears to be less of a "close call"). At least for now, KGRI appears "safely" VFR, but should this area of fog and/or stratus advect a bit farther north-northwest than currently anticipated, the going VFR forecast could really fall off the rails fast, so this certainly bears watching...just in case. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ UPDATE...Pfannkuch DISCUSSION...Wesely AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Indianapolis IN
1004 PM EST Tue Nov 22 2022 .Forecast Update... Issued at 1002 PM EST Tue Nov 22 2022 Looking at the latest observations this evening, temperatures appear to be highly dependent on topography and local wind conditions. Readings from near 30 to around 40 degrees were common across the area. Large differences in temperature across short distances were apparent as well, with 5 to 10 degree variations within 10 or so miles. Made slight adjustments given the current obs and continued stabilization of the boundary layer, clear skies, and decreasing winds. Kept low temperatures largely the same for most locations, but added weight to hi-res models such as the HRRR which seem to have a better grasp on the finer details seen in obs. Adding more weight to the hi-res guidance allows forecast temps in features such as river valleys to be a tad cooler than surrounding areas. Vice versa for slightly elevated areas. Such adjustments should help better capture the localized variability, as is common under temperature patterns driven primarily by radiational cooling. Aside from that, sky and wind grids look good with no changes made. && .Short Term...(This evening through Wednesday) Issued at 250 PM EST Tue Nov 22 2022 * Warming trend continues through midweek with highs nearing 60F * Very dry conditions persist .This evening and tonight... Current surface analysis shows surface high pressure stretching from Texas towards the Mid Atlantic with lower pressure across the Northern Plains and along the Front range. Clear skies are found across the entire state as a very dry atmosphere and subsidence under the high are keeping any clouds and precipitation away. 18z IND ACARS soundings shows a very similar picture this afternoon as the past few days with a shallow mixed layer near the surface bringing down slightly drier air and stronger winds aloft. Today, the LLJ is much weaker than yesterday resulting in sustained winds only around 10-15 kts with gusts remaining under 20 kts so far. With such a dry environment, temperatures have soared with ample sunshine well above NBM 90th percentile high. Have continued to bump highs up into the mid and even upper 50s across the region for this afternoon and evening. Expect temperatures to plummet once again tonight as conditions will be conducive for radiational cooling to take place. Despite the center of the high south and east of the region, the pressure gradient is still weak enough for winds to relax and even go calm in a few wind sheltered areas. With dew points in the lower 20s this afternoon, would not be surprised to see many areas reach the mid to upper 20s by tomorrow morning. Lower 30s likely around the Indy Metro due to the urban heat island. .Wednesday... Very similar synoptic set up tomorrow with high pressure remaining across the Mid Atlantic states and low pressure continuing to develop across the western Plains in response to a deepening upper trough. Southerly flow continues to slowly advect a warmer airmass into the region as highs have been a few degrees warmer than the previous day each day this week. With increasing upper heights and temperatures aloft at 850mb rising from around 2C today to up to 6C tomorrow, max temperatures will likely be pushing 60 degrees, especially in known warmer areas such as the Indy Metro. Forecast soundings show mixing heights up around 2-3 kft, so expect dry air and stronger winds to mix down to the surface again during peak heating of the day. With weak moist air advection taking place with persistent southerly flow, dew points and RH will be slightly higher than the previous day. Still, with such dry conditions at the surface, expect RH values to significantly drop during the afternoon making for a slightly elevated fire threat. Winds are not expected to be strong with max gusts around 10-15 kts according to forecast soundings. Did similar forecast techniques as the past few days since it has been verifying well and the pattern is remaining largely the same. For max temperatures and winds going above NBM 90th percentile, while trending towards the lowest end of guidance for Dew Point and RH values due to afternoon mixing and very dry antecedent conditions. && .Long Term...(Wednesday night through Tuesday) Issued at 250 PM EST Tue Nov 22 2022 * Mild and Dry through Thanksgiving * Rain Chances return late Thursday Night through Sunday Thanksgiving... A ridge axis over the Mountain West will progress eastward, supported by moderate 850-750mb WAA within SW flow. This flow will also provide some moisture return, with a saturating moisture profile above 800mb. Thursday morning will still be rather dry with mostly clear conditions outside of upper level cirrus within a strong upper level jet. Clouds will fill in throughout the day as the upper atmosphere saturates. The PBL should be well mixed with the near surface layer remaining dry. This should promote efficient warming, with a slight cap on the afternoon with increasing cloud cover. Expect afternoon highs in the upper 50s to low 60s. Thursday Night through Friday... An upper level trough will near from the west/northwest Thursday night. The main vorticity lobe in the trough apex will separate from the polar jet, leaving a weakly forced upper to mid level trough over the upper Midwest. Precipitation over the Tennessee Valley will limit surface moisture return, but the upper to mid levels will be saturated. A seeder feeder effect within weak ascent should be enough for light rain to occur overnight. QPF will be marginal, with current expectations of less than 0.20". The trough axis will exit Friday morning, with increasing heights promoting large scale subsidence by Friday afternoon. Temperatures will remain mild with little to no CAA behind the trough. Saturday and Sunday... The aforementioned vort max displaced from the polar jet will progress to the NE later this week within a strong subtropical jet streak on its eastern flank. This will once again push warm air over the Ohio Valley, keeping conditions mild even with sustained cloud cover. As the upper level low pushes NW, surface cyclogenesis is likely to occur to its NE, quickly occluding as the Dry Conveyor Belt wraps around. This should place a vertically stacked low over the Western Ohio Valley late Saturday into Saturday night. Surface moisture return should be much more sufficient for this event, and with strong ascent within CVA, bands of moderate rain will likely form. This should lead to higher QPF within this event (0.5-1.0"). There is still a lot of uncertainty with the track of the closed low, leading to a wide array of precipitation solutions both timing and amounts. By Sunday night, the low should be out of the region, with precipitation chances decreasing rapidly. && .Aviation...(00Z TAF Issuance) Issued at 618 PM EST Tue Nov 22 2022 Impacts: * None Discussion: VFR conditions are expected through the TAF period at all terminals. Broad surface high pressure to our southeast will allow winds to retain a south-southwesterly component through tonight and most of tomorrow. A decaying cold front approaching from the northwest will cause the surface pressure gradient to weaken a bit, so lighter winds are expected tomorrow compared to today. Nevertheless, some occasional gusts to around 10kts are possible at times during the afternoon. No sensible weather is expected with the weakening front, but some high clouds may begin to stream in from the southwest after about 21z. Winds remain light into Wednesday evening, but slowly become southeasterly after 00z as the surface high moves to the northeast. && .IND WATCHES/WARNINGS/ADVISORIES...None. && $$ Update...Eckhoff Short Term...CM Long Term...Updike Aviation...Eckhoff
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 333 PM CST Tue Nov 22 2022 Key Messages: - Mild weather, highs in the 40s and 50s, sticks around through next Tuesday. - Thanksgiving travel should be free of significant weather related disruptions in eastern Nebraska and western Iowa. At 2 PM, fair skies prevailed across Iowa and Nebraska. A weak surface front was hanging out just north of Interstate 80. South of the front temperatures over preformed today, with both Lincoln and Omaha cracking the 60 degree barrier. Tonight & Wednesday: A weak frontal boundary will be draped along the Interstate 80 Corridor tonight. North of the boundary skies should be fair and overnight lows should dip into the upper teens or twenties. South of the boundary there is a small chance (10%) of fog developing by sunrise Wednesday due to low level moisture advection. Right now the NAM with its tendency towards a wet bias remains the most aggressive guidance, but there are hints of near surface saturation in the HRRR and WRF ARW. If fog forms, it would be most likely from Beatrice to Falls City to Shenandoah. A upper level trough over the Rockies and developing lee trough over the High Plains will bring steady southerly winds back to the Plains on Wednesday. This should keep weak low level WAA and moisture advection going through the day and push afternoon highs into the 50s. Increasing clouds are expected Wednesday evening. Wednesday Night through Friday: During this period the trough over the Rockies will dig south, and evolve into a cutoff low over Texas. Meanwhile a cold front should push east through Nebraska and Iowa. Northwest winds behind the front will usher a cooler airmass into our region and we expect temperature declines of about 10 degrees on Thanksgiving (compared to Wednesday). Our going forecast has afternoon highs in the 41 to 46 degree range. Low level moisture should continue to deepen Wednesday night. This could lead to a 2,000 to 4,000 ft saturated layer by Thursday morning, and result patchy drizzle develop along and south of Interstate 80. For now the majority of the guidance keeps surface temperatures above freezing Thursday morning and so any drizzle should be a travel nuisance rather than a frozen problem. We will continue to monitor just in case a narrow window for freezing drizzle develops behind the front. Drizzle chances should fall through the day on Thanksgiving as the surface front pushes eastward. Winds behind the front will be breezy from the north, with occasional gusts near 35 mph. The drier weather pattern should linger through the day on Friday. Over the Weekend: Ensemble and deterministic guidance continue to struggle with the closed low lifting out of Texas on Saturday. Overall the trend has been towards a slight northern shift in track over the last 36 hours. This places southeast Nebraska and southwest Iowa on the northern periphery of the system Saturday afternoon. If some precipitation does occur, it would likely be rain given the diurnal timing. We will continue to monitor, but for now the greatest precipitation chances remain over Kansas and Missouri. Temperatures over the weekend should be close to seasonal averages with highs in the 40s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 520 PM CST Tue Nov 22 2022 Quiet TAF period with VFR conditions prevailing. Winds are becoming light and variable now and will become SSE by Wednesday morning. They`ll slowly gain speed from about 5 knots to about 11 knots by Wednesday evening. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Albright AVIATION...Nicolaisen
Area Forecast Discussion
National Weather Service Reno NV
110 PM PST Tue Nov 22 2022 .SYNOPSIS... Quiet weather will continue through Thanksgiving Day with mainly light easterly winds and near to slightly below normal temperatures. Friday into the weekend, temperatures will warm with a turn to more southwesterly winds, ahead of what could be a series of winter storms Sunday into mid next week. While confidence in specific scenarios is low, periods of wind, rain, or snow are possible for travelers heading home from the holiday weekend. && .SHORT TERM... A dry cold front moving through the Great Basin tonight will help kick up NW winds aloft on ridgelines to around 20-30 MPH but with only minimal increase in wind for lower elevation valleys. With main cold air off to our east, temperatures over the Sierra & W Nevada don`t cool off that much such that lower valley inversions may persist into Wednesday. That means some haze or patchy dense fog is possible again, such as around Mono Lake, but confidence is lower than last couple nights. Current thick high clouds likely to continue at least through the evening per HRRR guidance. By sundown Wednesday into early Thursday morning, winds aloft shift to more of a E/NE direction which favors some strong gusts over the Sierra crest, but nothing too bad given 700mb wind speeds of only 15- 25 knots in latest GFS. We might see some of that easterly flow surface around Lake Tahoe Wednesday afternoon and evening, per latest HRRR and NAM 3km, but not nearly enough for lake wind advisory conditions. Otherwise most valleys will remain light and variable on the winds with near to just below normal temperatures. -Chris .LONG TERM...Thanksgiving Day onward... Expect dry and mild conditions to continue on Thanksgiving day, as the ridge axis amplifies over the CA/NV border. Skies will be mostly clear, with some haze from valley inversions lingering in urban locations. Near-average temperatures and light winds will continue. We will see similar conditions persisting through Friday as the ridge lingers over the western US, though temperatures will run a few degrees above-average. Perfect conditions to get outside and enjoy the holiday weekend with loved ones! A trough will begin to deepen off the coast of British Columbia on Saturday afternoon, subsequently nudging the ridge east and opening the door to more active weather for the end of the weekend into early next week. Our next main storm system looks to arrive Sunday, and here`s what we know and don`t know so far: * WINDS: There are some discrepancies between models at this time regarding the potential for gusty winds ahead of the main storm system. The ECMWF ensemble shows the aforementioned trough splitting off the coast of the Pacific Northwest and ejecting a shortwave into northern CA/NV. If this scenario verifies, gusty winds could develop as early as Saturday morning. Instead of splitting the trough, the GFS ensemble suggests the trough will continue to drift eastward over Canada. This scenario would produce no impact to our region, with lighter winds continuing until the main storm system arrives on Sunday. Confidence is higher in terms of winds for this main system, with gusty winds developing across the region on Sunday afternoon. Winds are expected to peak Monday morning as a cold front pushes through our region. Ridge wind gusts in excess of 60 mph are possible, and valleys will see gusts between 15-25 mph. * RAIN/SNOW: Given the ECMWF trough splitting scenario, we can`t rule out some light precipitation along the Sierra crest on Saturday morning. However, chances for this scenario are lower (10% chance). The main system brings a more promising chances for measurable precipitation Sunday afternoon through Tuesday morning as models are generally trending wetter. Snow showers are likely (70% chance) to begin along the Sierra crest on Sunday night and continue through Monday. Precipitation looks to begin in valley locations early Monday morning, though precipitation type is uncertain at this time. However, nearly all ensemble members have at least a trace of snow down to the valley floors, so it looks likely that precip could change to snow at some point as the cold front passes through. Precipitation is expected to wind down overnight on Monday, with some lingering mountain snow showers through Tuesday morning. -Whitlam && .AVIATION... Another day of strong valley inversions with haze and light winds today. Brush-by dry cold front tonight will help increase NW winds aloft but only minimal wind increases in valley locations. Thick high clouds will move over the area through at least this evening. Flow on Wednesday turns more E/NE. This pattern typically results in only limited wind increases for valleys except around CXP which responds well to E/NE patterns. A few strong gusts over the Sierra crest from Tahoe south to near Mammoth are a good bet, with that increased E/NE flow, there could be some wind shear issues near TRK/TVL Wednesday evening and night. -Chris && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$