Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/21/22

...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 357 PM CDT Thu Oct 20 2022 .Key Messages: -A dynamic storm system is expected to reach the area Sunday -Strong winds, record high temperatures, severe storms, and potentially dangerous fire weather are on the table -Very strong winds will likely linger into the work week .Today through Saturday: Afternoon water vapor imagery showcases a departing trough centered over the eastern third of the CONUS with high-amplitude ridging taking hold of the western two thirds. This will set the tone through Saturday, with increasing temperatures, docile winds, and dry conditions being the expectation. As temperatures rise, moisture isn`t exactly going to be pouring in the area so we`ll be forecasting very dry afternoons. Highs will climb to the upper 70s to near 80 Friday, and just above 80 degrees Saturday while relative humidity values during the afternoon hours fall to 15-25% both days. Fire danger is expected to be high to very high, but not extreme due to the wind speeds being relatively weak. With that said, Saturday`s are slightly higher and could gust to 25 mph with 15 mph sustained winds. .Sunday through Monday: The main concern of the forecast period begins taking shape Saturday evening as a deepening trough develops over the Intermountain West that quickly deepens overnight into a dynamic trough as it enters the central CONUS midday Sunday. Before we get to too many details, there still is significant spread on the location of the main surface low Sunday, that could shift the areas that see each of the following concerns east or west. As the trough deepens, strong wind fields at all levels ramp up moisture return from the south and brings several hazards to the table. By the time the eventual cold front/dryline features reach the area, dewpoints will have climbed 50s to just over 60 in eastern portions of the forecast area resulting in meager instability to go with the very strong shear. Severe storms will be possible, primarily during the early evening hours. Damaging winds are the primary concern, though hail and a tornado or two could be possible for a narrow corridor of eastern Nebraska and southwest Iowa. Farther west in areas where the fronts and overall system arrive early, extremely dry and windy conditions will develop and increase fire danger to the very high and extreme ranges; especially closer to central Nebraska. Very strong winds also join into the fray area-wide Sunday through Monday where wind gusts at 45 to 55 mph appear to be nearly a lock to occur. Some spots could see those numbers incensed by 5 to 10 mph where the strongest winds end up (mainly under the main low- level jet streak). With those winds, the already dry conditions will result in areas of dust and lowered visibility along with damage to trees that haven`t quite lost their leaves yet. On a note of lesser importance, the strong southerly flow will also result in high temperatures that are forecast to break records Sunday afternoon: Forecast Record Omaha -- 85 84 (from 1899) Lincoln -- 87 84 (from 1915) .Tuesday and Wednesday: By the time we get to the middle of the work week, significant spread is observed both between models and between members of the same ensemble. What will be better bets weather-wise is less wind, dry weather, increasing potential for another storm system late week into the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 614 PM CDT Thu Oct 20 2022 VFR conditions are expected through the TAF cycle. Broken high clouds continue to pass overhead and should continue to do so through the overnight hours. HRRR smoke modeling shows mostly high-level smoke from fires across the Pacific northwest spreading across our sites by daybreak Friday and continuing through Friday afternoon. Otherwise, low-level shear looks likely, especially at KOMA and KLNK as winds out of the southwest develop at FL003 from 08-12z. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Petersen AVIATION...Kern
Area Forecast Discussion
National Weather Service Norman OK
1041 PM CDT Thu Oct 20 2022 ...New AVIATION... .SHORT TERM... (This evening through Friday) Issued at 249 PM CDT Thu Oct 20 2022 Dominant story in the short-term will be fire weather concerns Friday. For further information, see the fire weather section below. Winds will swing around from northerly to southerly overnight as a weak surface low travels southeastward across the Red River and decays. In its place, a lee trough will deepen overnight to our north and west. Return flow will be largely dry, and mixing will most likely counteract some modest moisture advection. With the strength of downsloping southwesterlies and clear skies in place, expect tomorrow to be very warm, with temperatures ranging from 85 in the southeast part of our CWA to near 90 elsewhere. Winds will be gusty from the southwest, with peak gusts of 25-30 mph expected west of I-35. Meister && .LONG TERM... (Friday night through next Wednesday) Issued at 249 PM CDT Thu Oct 20 2022 Fire weather will continue to be a prominent weather story in the long-term. For further information on fire weather both Saturday and Sunday, see the fire section below. By Saturday, upper-level flow will veer to westerly as the STJ phases with the primary mid-latitude jet to our west. This pattern will encourage intense pressure falls to our north, with a surface trough deepening across the High Plains from north of Casper all the way to Midland. Strong southerly flow will encourage trajectories off of the Gulf with return flow over the eastern half of our CWA. A dryline should sharpen on Saturday, with the stronger winds actually found in the moist sector where the pressure gradient will be tighter between the lee low and a surface high over the East Coast. Gusts could reach 30 mph or greater along and east of I-35. High temperatures will again be well above average, especially west of the dryline where highs may breach 90 degrees in multiple spots. On Sunday, the surface trough will consolidate into a cyclone over the Central Plains as the mid-latitude jet prepares to eject. The expectation is that the low will deepen to sub-990 mb as it travels across Nebraska Sunday afternoon, which will generate strong gradient southerlies across our CWA. Most models show some cloud cover remaining in place over the moist sector, and dewpoints may approach 60 degrees on the moist side. However, the advection of a strong EML cap will prevent convection initiation within an otherwise modestly unstable environment. Winds will be very strong during the afternoon Sunday, with widespread gusts over 40 mph and possibly as high as 50 mph possible north of I-40. The overall timing of this system continues to slow down. Thus, the frontal passage that originally looked like it may occur Sunday night across our CWA now looks like it may be delayed until Monday. Kept PoPS in the forecast from Sunday night into Monday, but with the ongoing trend it`s possible that postfrontal precipitation doesn`t develop in our area until Monday afternoon. Once the cold front passes, the global models diverge to a comical degree regarding the potential for rain Monday into Tuesday. The GFS phases the upper-level trough with a cutoff low over the east Pacific while simultaneously merging those features with a tropical system traveling northward out of Mexico. The Canadian agrees in principle with that solution. Both of those models develop widespread soaking rainfall. The ECMWF, on the other hand, lifts the trough northward before it can impact our area, leaving us high and dry. To complicate matters further, neither operational model agrees with its own ensembles. We`ll continue to wait for more clarity regarding precipitation chances and a possible cooldown early next week. Meister && .AVIATION... (06Z TAFS) Issued at 1039 PM CDT Thu Oct 20 2022 Southerly winds will increase toward and after 15Z, with gusts 20 KT to 30 KT during the afternoon, strongest across western Oklahoma. No restrictions expected. && .FIRE WEATHER... Issued at 249 PM CDT Thu Oct 20 2022 Fire weather will be problematic each of the next three days. Sunday continues to look like the most volatile day of the three, while tomorrow looks like the largest areal extent to deal with fire weather. Tomorrow, dry return flow south of the developing surface trough will encourage downsloping and deep, well-mixed boundary layers. Winds within a southwest-northeast axis from southwest Oklahoma to north-central Oklahoma should be around 20 mph sustained with gusts near 30 mph. Relative humidity will drop to about 10 percent in northwest Oklahoma and 25 percent in southeast Oklahoma. Given the extremely dry fuels and problematic fire spread in recent weeks in marginal fire environments, issued a red flag warning for tomorrow anywhere that relative humidity will drop below 20 percent. Issued a fire weather watch for south central and southeast Oklahoma, where humidity will need to be watched. The RAP is more aggressive in mixing out some slight moisture advection than the NAM. Dry return flow events have a tendency to overperform in this region, and it will be watched closely for potential red flag warning issuance in the next forecast. The location of elevated fire weather will become more spatially limited on Saturday, as moisture return will likely set the dryline up in western Oklahoma. Fire weather will still be elevated during the day on Saturday in western Oklahoma and far western north Texas, where relative humidity will drop to 15 percent or so. However, we do not anticipate red flag warning criteria to be met, as the driest air and strongest winds do not overlap. Sunday could potentially be a very volatile fire weather day, as the synoptic-scale jet streak ejects across the central Plains. A low- level thermal ridge will develop northwest of the dryline. Its intersection with the jet streak will be closely watched for potential critical fire weather. This is still an uncertain forecast given the possibility that the dryline may set up far enough west to keep us entirely within the moist sector. However, if portions of northwest Oklahoma end up behind the dryline, relative humidity as low as 15-20 percent can be expected with winds gusting as high as 45 mph. Meister && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 49 86 60 86 / 0 0 0 0 Hobart OK 48 87 56 89 / 0 0 0 0 Wichita Falls TX 49 90 62 93 / 0 0 0 0 Gage OK 46 89 47 88 / 0 0 0 0 Ponca City OK 45 89 58 86 / 0 0 0 0 Durant OK 47 87 60 84 / 0 0 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...Red Flag Warning from 1 PM to 8 PM CDT Friday for OKZ004>027- 033>039-044-045. Fire Weather Watch from Friday afternoon through Friday evening for OKZ028>032-040>043-046>048-050>052. TX...Red Flag Warning from 1 PM to 8 PM CDT Friday for TXZ083>090. && $$ SHORT TERM...04 LONG TERM....04 AVIATION...11
Area Forecast Discussion...CORRECTED
National Weather Service Pueblo CO
357 PM MDT Thu Oct 20 2022 .SHORT TERM...(This evening through Friday) Issued at 345 PM MDT Thu Oct 20 2022 Key Messages: 1) Red Flag Warning is in effect from 11am - 7pm for the lower elevations of Pueblo, Huerfano, and western Las Animas Counties, primarily for the gap flow prone areas. 2) Well above average high temperatures are expected Friday afternoon. Currently and the Rest of Tonight.. Very dry air has been observed across the lower elevations. The lowest dew point observed today, so far, was -5F at KAFF at around 1PM this afternoon. Winds have been light, so no critical fire or near critical fire weather conditions have been observed. Looking at satellite and out our window... it is hard to even find a cloud in the sky, outside of thin cirrus over the mountains. This air mass is DRY. West to southwesterly winds are expected over the southern plains throughout the overnight, so I bumped up winds as compared to guidance around the region, but the lower Arkansas River Valley and north may have temperatures near freezing, but not close enough to issue any frost related highlights. Tomorrow: I believe the low dew points being observed today only indicate the type of air mass that we will experience tomorrow, therefore I decreased dew points across the area using a model blend of the previous forecast and the HRRR 18z run. I used the 90th percentile for winds and wind gusts to increase gap flow wind values, since the coarser resolution models don`t handle the magnitude quite as well. Overall, that means that there will be critical fire weather conditions over the southern I-25 corridor from Pueblo to the New Mexico border. I would have added Fremont County, but the fuels were deemed not critical by the BLM in that area, but I do have to say that the meteorological conditions for critical fire weather will be there. Northern El Paso County is an area of uncertainty for critical fire weather conditions, but most guidance outside of the 90th percentile NBM says that the winds will be too weak. The split flow from Pikes Peak may not be resolved well enough, so perhaps the RFW will need to be extended there, however it has not been included in the RFW at this point in time. Outside of critical fire weather and gusty winds, tomorrow will be dry. .LONG TERM...(Friday night through Thursday) Issued at 345 PM MDT Thu Oct 20 2022 Key Messages: 1) Warm and breezy with critical fire weather conditions possible across the plains on Saturday. 2) Widespread snow developing Saturday night and Sunday across the higher terrain along the Continental Divide, with windy conditions expected across all of south central and southeast Colorado. 3) Cooler temperatures through the middle of week, with chances of precipitation continuing Sunday night and Monday. Friday night-Saturday...Latest models remain in good agreement of increasing west to southwest flow aloft across the region through the day Saturday, as a strong eastern Pacific storm system remains progged to dig across the Pacific Northwest Coast and into the Great Basin trough the day Saturday. With the increasing west to southwest flow aloft through the day on Saturday, combined with steep lapse rates and expected deep mixing, models continue to indicate critical fire weather conditions across most of southeast Colorado Saturday afternoon and into the early evening, and with that said have issued a Fire Weather Watch for all of the I-25 Corridor and southeast Plains. Slowly increasing moisture within the increasing southwest flow on Saturday will also bring increasing chances of showers to the ContDvd late Saturday afternoon. The increasing westerly flow will keep temperatures at and above seasonal levels, with highs in the 70s and 80s expected across the eastern plains, and mainly in the 50s and 60s across the higher terrain, save for 30s and 40s at the peaks. Saturday night-Sunday...Models continue to be in good agreement with the movement of Great Basin system across northwestern Colorado and into the Northern Rockies with a strong jet core translating across south central and southeast Colorado through the day Sunday. This will bring windy to very windy conditions to the region, with the potential for high wind warning criteria being met across portions of the southeastern Mts and southern I-25 Corridor late Saturday night and early Sunday morning, with h7 flow progged to increase to 50 to 60 kts. Strong westerly winds looks to spread east across the southeast plains through the day Sunday and will need to access later models data for the inclusion of a high wind watch for this timeframe. In addition, the strong west to southwest upslope flow and increasing moisture associated with the passing system, will bring widespread precipitation to the higher terrain, especially along and west of the ContDvd, where the first significant snowfall of the season. While total snowfall amounts continue to vary between advisory and warning criteria, the snow combined with the strong winds will create hazardous travel conditions across the higher mountain passes of the ContDvd late Saturday night and through the day on Sunday, with the first winter weather highlights of the season becoming more likely. With the strong winds, there will be continue to be high fire danger across the plains, however, latest guidance suggest slightly cooler temperatures and increasing moisture associated with the passing trough could keep rhs in the 15 to 25 percent and too high for critical fire weather conditions. With the passing trough, will see scattered scattered showers spreading across the high mtn valleys through the eastern mts Saturday night and Sunday, with some light snow accumulations possible as snow level drop to between 7-8K ft on Sunday. Sunday night-Tuesday...Models continue to differ on location of secondary energy digging across the region in the Sunday night and Monday timeframe, with guidance now shifting further south with said energy. While the Canadian model remains the most aggressive with precipitation across southeast Colorado with a closed low moving across northern New Mexico, the latest EC now develops a closed low across the Four Corners Sunday night which dives into southern New Mexico through Monday, with the latest GFS in between the other solutions. With such model diversity, have stayed with the NBM which keeps the best pops across the ContDvd Sunday night and early Monday, with chance pops spreading across the eastern mts and plains. As for temperatures, highs in the 60s and 70s early Sunday across the plains, cool into the 50s on Monday, with the potential for a widespread hard freeze across the plains Monday night and Tuesday night. Wednesday-Thursday...Cool northwest flow remains progged across the region through the middle of the work week, with another system possible digging across the Intermountain West later next week. Current NBM keeps temperatures below seasonal norms through the middle of next week, with slight chances of precipitation across the higher terrain, mainly along the ContDvd. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 345 PM MDT Thu Oct 20 2022 VFR conditions are expected at all three TAF sites, KCOS, KPUB, and KALS, for the next 24 hours. Sky conditions are expected to be clear, with no precipitation, and light diurnally driven winds throughout the majority of the forecast period. By tomorrow afternoon gusty winds are expected over KALS and KPUB, whereas KCOS may be stuck in an eddy producing southeasterly return flow. If that occurs LLWS may be an issue tomorrow afternoon. && .PUB WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Saturday morning through Saturday evening for COZ226>237. Red Flag Warning from 11 AM to 7 PM MDT Friday for COZ228>230. && $$ SHORT TERM...SKELLY LONG TERM...MW AVIATION...SKELLY