Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/03/23

Area Forecast Discussion...Updated
National Weather Service Billings MT
802 PM MST Mon Jan 2 2023 .UPDATE... Light snow over far southern areas will gradually diminish overnight as an upper low continues to slide east. Have gone ahead and updated PoPs to latest trends. Fog is expected to develop overnight, mainly from Billings and areas to the east and south. With saturated low levels and light winds, some of the fog could be dense with visibility below a 1/2 mile at times. Will continue to monitor for potential Dense Fog Advisories. The previous discussion is below. STP && .DISCUSSION... Tonight through Wednesday Night... Low pressure moving E through CO, will shift into NE/KS tonight. A wave will rotate NNE out of the low into MT, pushing a low chance (20-30%) of snow N into S. Big Horn County E through Carter County this evening. A chance of snow will also continue over Sheridan County. Added 20% PoPs to areas from Lame Deer to K4BQ S late tonight to account for the wave and also had low PoPs over west-facing slopes of the Beartooths/Absarokas due to moist SW flow over this area. Due to low QPF`s, the NBM 24 hr probability of an inch of snow was around 20% S of KSHR through 18Z Tuesday. Kept a slight chance of snow over the SW mountains on Tue. due to lingering RH and SW flow. Other concern for tonight was fog from KBIL E and S mainly in the valleys. HRRR showed potential for areas of fog, possibly dense, in these areas tonight into Tue. morning. KMLS had a brief period of dense fog earlier today. Areas of snow cover over much of SE MT and any snow that moves in will provide moisture for fog, but amount of cloud cover will limit radiation potential. Therefore went with patchy evening fog, increasing to areas of fog overnight from KBIL E and S in the valleys and decreased the fog by 18Z Tue. Future shifts will need to watch for the potential for dense fog. There will be a trough over W MT Tue. night with high pressure over the E. Trough scoots by N of the Canadian border on Wednesday while an upper ridge builds in from the W Wed. and Wed. night. While the weather will be dry, a favorable pressure gradient for windy conditions in the gap areas and 191 corridor sets up Tue. evening and continues through Wed. night. 700 mb winds were not favorable for Advisory strength winds in the gap areas and the pressure gradient will be increasing and decreasing through the period. Expect strongest winds (sub-advisory wind speeds) late Tue. night through Wed. morning. High temps will trend warmer through the 30s through Wed., with some 20s E of KBIL. Arthur Thursday through Monday... Pacific flow with near to above normal heights will keep our region mostly dry thru the weekend and into early next week. The only exception to this seems to be tied to a weak shortwave Thursday night and Friday. Temps should remain cold enough for p-type to be mostly snow, but forcing is quite weak and any precip should be light. Generally speaking, looks like a couple inches of snow for the mountains and a half inch or less of wet snow for lower elevations. Probabilities of an inch or more of snow accumulation are 10% or less across lower elevations, 25-35% along the foothills and Wolf Mountains, and up to 70% over the Beartooth-Absarokas. Saturday through Monday should be dry as ridge re-establishes itself. There could be some light orographic snow over our western mountains by early next week. Temperatures should hold in the 30s Thursday, then rise to the mid 30s to mid 40s most days thereafter (eastern valleys may be a bit colder initially). Western/central areas could push 50F by early next week as flow aloft backs southwesterly over time. The evolving warmer & drier weather pattern is supported by a strong zonal jet across most of the Pacific Ocean. This will continue into next week, but there are signs of this jet breaking down by the middle of January. This may give hope for a pattern shift beyond 10 days from now. JKL && .AVIATION... Overall, greatest potential for sub-VFR thru this evening is at KSHR (i.e. northeast side of the Bighorns), where flight conditions will be mostly MVFR in periodic light snow. Localized fog is possible across the entire region tonight and Tuesday morning, with potential IFR or less in valleys. Greatest risk of fog seems to be at sites KMLS & KBHK, but the entire region needs to be monitored. Otherwise, the Bighorn Mountains will continue to be obscured tonight. Other than locations with morning fog, lower elevations will see VFR prevail tomorrow. JKL && .PRELIMINARY POINT TEMP/POPS... Tue Wed Thu Fri Sat Sun Mon ----------------------------------------------------------- BIL 018/034 019/036 019/037 027/041 027/042 025/041 024/042 00/B 00/U 00/B 24/W 10/B 00/B 00/B LVM 017/034 017/033 019/040 030/041 025/039 023/040 023/040 00/B 00/N 01/N 43/J 00/B 00/B 11/B HDN 015/030 013/035 009/033 018/038 021/039 017/038 015/038 10/E 00/U 00/B 14/W 20/B 00/U 00/B MLS 010/024 013/030 007/027 012/030 020/034 014/032 013/032 00/E 00/B 00/U 02/J 10/B 00/U 00/B 4BQ 019/032 017/035 012/035 018/036 025/039 018/038 018/038 20/E 00/B 00/U 02/J 20/B 00/U 00/U BHK 008/026 008/026 009/028 011/028 015/032 014/032 014/032 00/B 00/B 00/U 01/B 10/B 00/U 00/U SHR 017/031 013/035 012/036 019/037 021/039 018/040 018/040 30/E 00/U 00/B 14/J 20/B 00/B 00/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Quad Cities IA IL
549 PM CST Mon Jan 2 2023 ...00Z AVIATION UPDATE... .SYNOPSIS... Issued at 245 PM CST Mon Jan 2 2023 Temperatures have been mild today by early January standards, remaining steady in the upper 30s to mid 40s this afternoon. Areas of fog have persisted through the day so far roughly along/south of highway 34 where dewpoints are in the low to mid 40s. The fog has been locally dense at times with visibilities under a half mile. A Dense Fog Advisory continues across the southern tier of the outlook area until 9 PM tonight, but could be cancelled early if visibilities improve. && .SHORT TERM...(This evening through Tuesday) Issued at 245 PM CST Mon Jan 2 2023 *Rain is likely tonight along with embedded thunderstorms *There is a chance for a period of freezing rain tonight, mainly north of highway 20 and west of Dubuque *Mild conditions are expected on Tuesday with highs in the low 40s northwest to 55 - 60 F central and east Widespread light to moderate rain is expected to develop quickly tonight as a strengthening low-level jet advects Gulf of Mexico moisture northward into the Midwest. PWATs will reach anomalously high levels for early January with NAEFS showing values beyond the 99th percentile. Strong forcing from deep warm air advection and increasing elevated instability should lead to bouts of heavier downpours and potential for scattered thunderstorms. Rain Amounts: There has been quite a bit of QPF variability in the models, but still thinking much of the area will receive between 0.50" to 0.75" by early Tuesday morning; narrow corridors that get hit but a few rounds of storms could end up with 1"+. Despite the ground being partially frozen in spots, thawing of the top layer should allow for some of the runoff to soak in. With that said, minor ponding of water is possible in low-lying areas, especially for locations that receive closer to 1" of rain. Ice Potential Tonight: There is a chance for a period of freezing rain along the highway 20 corridor (west of Dubuque) before the heavier precipitation moves in. A light glaze of ice is possible before midnight. Temperatures should then slowly rise into the mid 30s by early Tuesday morning. As the occluded front edges into the region on Tuesday, scattered low topped convection could develop beneath a mid-level dry slot. However, deep layer shear of 60+ kts may act to tear apart developing updrafts, given the marginal level of instability. This would limit convective organization as the front rolls through during the mid morning to early afternoon time frame. The HRRR is most aggressive on convective redevelopment and indicates a potential for isolated strong wind gusts. Other hi-res models show a weaker scenario with mainly showers developing along the front. .LONG TERM...(Tuesday night through next Monday) Issued at 245 PM CST Mon Jan 2 2023 Tuesday night...Full on dry slot should be getting whirled thru the area, with southwesterly BL flow eventually cool advecting from that direction as occluding low center drifts acrs the north central IA/MN border region. Before the warm front lifts to the north, convergent flow along it may produce fog and drizzle acrs the far north and northeastern CWA(DBQ into NW IL) thru mid evening. Wrap around precip from the approaching upper low will look get into the far northeastern to northern CWA overnight, with top-down dynamical cooling producing a rain-snow mix going over to mainly wet light snow from west-to-east into Wed morning. Temps ranging from low 50s in the southeast to upper 30s in the northwest at 00z, will cool to the low to mid 30s by 12z Wed morning. Wednesday and Thursday...This period dominated by large slow- rolling/partially blocked upper low sliding acrs the region with rounds of mainly light snow showers and flurries. Have upped the POPs for occurrence and coverage, if only for light QPF. Most areas to get a half inch to a wet dusting during the day, much may melt on pavement with radiational effects and high temps in the mid 30s. A bit better chance for light snow accums on pavement after dark Wed night, with light snow showers spreading from northwest-to-southeast as the night progresses, highest coverage occurring almost CWA-wide after 06z-09z Thu morning. An isolated swath with a few areas pushing an inch possible by Thu morning, but hard to define where that may occur at his point, maybe north of Hwy 30. Will walk the light snow showers and flurries acrs the area on Thu with higher coverage settling east of the MS RVR by afternoon. Again low to mid 30 highs and diurnal effects to limit much of snow accum potential besides a few tenths on grassy/elevated surfaces. Friday through next Monday...Dry and moderating temps some(mid to upper 30s southern 3/4`s of the fcst area) with incoming sfc ridge, chilly Friday night in the 20s to upper teens. Then many of the recent deterministic medium range models as well as some ensembles diverge into the start of the weekend with phasing of northern and southern stream upper wave/trof energy. They very from mainly unphased keeping the area in between systems and dry, to some phasing which could lead to a wintry mix scenario in or near the local fcst area Friday night into parts of Saturday. The blend loaded POPs a bit later more for light snow Sat afternoon and night, but that may be a bit slow looking at latest ensemble trends...if indeed we manage to get any precip at all. Looking mainly dry and seasonable int early next week. ..12.. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 549 PM CST Mon Jan 2 2023 As a wet storm system moves into the region, flight conditions should deteriorate from south to north as higher moisture air builds in. As of TAF issuance, BRL continues to be under LIFR ceilings, with MLI under MVFR ceilings. The expectation is that the LIFR ceilings, along with MVFR/IFR visibility reductions due to light/moderate rain, will expand to impact all TAF terminals over the next several hours. Some embedded thunderstorms may bring some brief heavy rain to the terminals, but confidence is very low regarding the coverage of these storms, so will leave out of the TAFs for now. Some gusty north-northeast winds will be possible this evening into the early Tuesday morning hours, as well. Eventually, a dry slot will move in late tonight into Tuesday morning, which should put an abrupt end to the rain. However, there could be a line of showers and even some thunderstorms moving through during the mid- to late-morning hours. With the dry slot, VFR ceilings are possible for MLI and BRL as stratus scatters out. && .HYDROLOGY... Issued at 1050 AM CST Mon Jan 2 2023 An areal flood warning continues due to a possible ice jam resulting in flooding near the Friendship Farm area along the Rock River on the Rock Island County side. This is between the Moline and Joslin gages. The latest report from local law enforcement this morning is that the flooding and water levels have fallen an estimated 4 to 6 inches from the levels that were reported Sunday evening. But with the river still being high and the potential for more ice action, will keep the flood warning going for now and check up this evening again on river level trends in that area. Joslin on the Rock River is still forecast to exceed minor flood stage by the middle of this upcoming week, approximately a little over 48 hours from now. However, confidence remains low on how much the river level will respond to the rain expected to fall tonight into Tuesday morning. If the basin receives less rain and run-off than currently forecast, the river level may stay below minor flood stage. But with possible ice action and the river already high/at action stage levels, even moderate rainfall may produce at least minor flooding. Thus went ahead and issued a River Flood Watch for the Joslin area starting Wednesday evening. && .CLIMATE... Issued at 300 PM CST Sun Jan 1 2023 Record Highs for Tuesday January 3 2023... Burlington...62 in 1998 Cedar Rapids...52 in 1998 Dubuque...55 in 1880 Moline...62 in 1998 && .DVN WATCHES/WARNINGS/ADVISORIES... IA...Dense Fog Advisory until 9 PM CST this evening for Lee-Van Buren. IL...Dense Fog Advisory until 9 PM CST this evening for Hancock- McDonough. MO...Dense Fog Advisory until 9 PM CST this evening for Clark- Scotland. && $$ SYNOPSIS...Uttech SHORT TERM...Uttech LONG TERM...12 AVIATION...Schultz HYDROLOGY...12 CLIMATE...Uttech
Area Forecast Discussion
National Weather Service Grand Forks ND
922 PM CST Mon Jan 2 2023 .UPDATE... Issued at 922 PM CST Mon Jan 2 2023 There are a few more 2 to 4 mile visibilities across the FA now, so the patchy fog is working out fine so far. The clouds along the North and South Dakota border now have a few more holes in them, but it still looks mostly cloudy overall. No changes needed to the forecast for now. UPDATE Issued at 608 PM CST Mon Jan 2 2023 Most of the northern half of the FA remains clear, with the exception of around Baudette, where there are some low clouds. To the south, high clouds continue to push northward, ahead of the snow system further south. Still kind of in a wait and see mode on the fog tonight (quite a few models have been showing fairly widespread fog developing). There has already been patchy development, so far mainly over southeast North Dakota into adjacent areas of west central Minnesota. && .SHORT TERM...(This evening through Tuesday night) Issued at 310 PM CST Mon Jan 2 2023 Key Messages: -Snow chances increase across portions of southeastern North Dakota and west central Minnesota beginning Tuesday morning and potentially persisting into early Wednesday. -Fog may be possible across the region tonight into Tuesday morning. -Near normal temperatures prevail. Discussion... The overall weather pattern aloft over the northern Plains throughout the short term will be tied to an upper level closed low moving across the central Plains. At the surface, a low pressure system ejecting out of the Rockies will track across the central Plains as well. While the main features of this attendant winter weather system look to remain to the south of this forecast area, some snow is expected across portions of southeastern North Dakota into west central Minnesota. Latest DESI guidance indicates that this area of snow will move northward into the region Tuesday morning, generally ending by Wednesday morning. Overall, ensemble suites are keeping the heaviest snowfall to the south of the forecast area, but there are still some individual members that introduce a band of moderate snow to west central Minnesota on Tuesday. Given that this is a lower end (~20% chance) scenario, there is higher likelihood that this remains a light snow event, but cannot completely rule out at least the potential to see higher snowfall totals. Overall, the expectation is for a Trace to 4 inches of new snow along and south of the I-94 and Highway 10 corridor, with highest totals across Grant County in Minnesota. Regardless, there is high confidence that areas generally north of the I-94 and Highway 10 corridor will be hard pressed to see much in the way of snowfall outside of a few stray flurries. Furthermore, fog will be possible overnight tonight into Tuesday morning ahead of the expected snowfall. As the system to the south gradually moves northward, the expectation is for moisture to advect into the northern Plains as well. As temperatures cool overnight and winds become more or less calm to light, fog should develop in some areas. The biggest questions at this time are in regards to the spatial extent and intensity of any fog that does develop. Latest short term ensemble guidance varies, with the HRRR being the most bullish on fog development, introducing widespread visibilities less than a half mile, while various WRF runs keep visibilities 5 miles or greater. As a result, ensemble suites show quite a wide spread in potential outcomes with respect to fog development that will continue to be monitored throughout the evening and overnight hours. Otherwise, with the bulk of the winter storm remaining south of the forecast area, look for very little variation in temperatures across the short term period. Highs in the teens, with lows in the single digits are expected as a result, with variations only as a result of cloud cover or fog that does develop. While some light snow may linger into early Wednesday morning across west central Minnesota, mostly quiet weather is otherwise expected to prevail across the rest of the region. .LONG TERM...(Wednesday through Monday) Issued at 310 PM CST Mon Jan 2 2023 Minimal concerns in the extended time frame as ensemble and cluster solns bring 500mb ridging to the area for the end of the week into the weekend. As a result minimal accumulations and temperatures around the seasonal normals are expected. Timing of the ridging and if there is a clipper system or not within the northwest flow aloft ahead of the ridge will still need to be watched. NBM probs of more than a tenth of an inch Thursday into the weekend are less than 10%. With respect to the temperatures, highs are expected to be in the teens maybe touching 20 by Sunday or Monday next week. As is typical for wintertime and snowcover, lows will fall into the single digits above or below zero depending on cloud cover.&& .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1154 AM CST Mon Jan 2 2023 Current trends are for cigs to gradually improve to MVFR to VFR throughout the afternoon, with lowest cigs at TVF and BJI. Cigs then lower across the evening and overnight hours as low level moisture streams northward from the winter storm system to the south of the forecast area. Some fog will likely be present during the overnight and Tuesday morning hours as well, but the spatial and temporal aspects are still somewhat uncertain at this time. Otherwise, already light winds become light and variable overnight into Tuesday. && .AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon) Issued at 1154 AM CST Mon Jan 2 2023 Current trends are for cigs to gradually improve to MVFR to VFR throughout the afternoon, with lowest cigs at TVF and BJI. Cigs then lower across the evening and overnight hours as low level moisture streams northward from the winter storm system to the south of the forecast area. Some fog will likely be present during the overnight and Tuesday morning hours as well, but the spatial and temporal aspects are still somewhat uncertain at this time. Otherwise, already light winds become light and variable overnight into Tuesday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...Winter Weather Advisory from 6 AM to 9 PM CST Tuesday for MNZ040. && $$ UPDATE...Godon SHORT TERM...Rick LONG TERM...JK AVIATION...Godon
National Weather Service Wilmington OH
1020 PM EST Mon Jan 2 2023 .SYNOPSIS... Temperatures will remain well above normal for the next couple days, with increasing chances for rain tonight into Tuesday. A cold front will progress through the region Wednesday, bringing cooler conditions for the rest of the week. Drier conditions evolve for the end of the workweek, with just a low end chance for a few light rain or snow showers Thursday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Evening update... Dense fog advisory: Visibility has improved over the last hour, but will hold on to the dense fog advisory for another hour or two to confirm. Heavy rain: Adjustments in PoPs and QPF were very minor this evening as the general expectations (see previous discussion below) are unchanged. Latest infrared satellite shows a persistent area of very cold cloud tops, associated with long- lived thunderstorms, moving northeast up the lower Ohio River Valley region. This will move into the tri- state and surrounding areas over the next few hours, bringing in the first round of moderate rain with embedded thunder and locally heavy rain. There remains high confidence in widespread moderate rainfall amounts up to an inch tonight, but the focus this evening, has been on the locally heavy rainfall amounts and location. Latest HRRR runs and other 00Z guidance continues to highlight portions of the tri-state and along/southeast of I-71 to have the greatest potential for observing locally heavy rainfall amounts greater than 1.5". Low level jet magnitude, anonymously high atmospheric moisture content, and embedded thunderstorm elements all support the possibility of this occurring. Current thunderstorm activity across western Kentucky continues to produce frequent lightning activity and locally heavy rainfall amounts up to 2". This will be the area to watch over the next few hours, as the low-level jet surges northward into northern Kentucky and southern Ohio. After the first wave moves through between 06Z-12Z, continued development along the convergence axis will likely determine the magnitude of the locally heavy rainfall and resultant flooding. Anonymously high moisture content persists through mid- morning, so any remaining convective elements will be capable of producing locally heavy rainfall rates. Previous discussion (234 PM)... Amplification to the mid-level pattern, with ridging off the SE coast and a deepening upper low in the central plains, will promote an enhanced LLJ nosing N into the ILN FA around/after midnight. Data remains in good agreement showing an arc of RA/TSRA moving into N KY into the Tri-State around midnight before the activity spreads to the NE and expands through the heart of the overnight. This initial round of activity does carry with it the potential for embedded thunder, courtesy of some elevated instby. There is a signal that there will be some lightning/thunder with this activity, and cannot rule out some some small hail, too. Nothing severe out of this initial round of RA/TSRA, but it may make quite a bit of noise as it rumbles through the ILN FA tonight into the predawn hours. A second push/concentration of steady/heavy RA/TSRA will occur toward daybreak and will move in from the W around this time. Still a bit of uncertainty just how much, if any, of a "break" there will be between the two surges of RA/TSRA, will some hi- res guidance not showing much of a break at all. Do think that a break /should/ develop near/S of the OH Rvr for a several hour period around 09z or so as the heavy RA briefly pivots N with the LLJ, with the "second" surge hanging back a bit to the W in central IN. With the incredibly deep saturation/anomalous PWATs and robust forcing, did add heavy rain to the forecast as many spots will receive >1.5" by the time the back edge of the rain /finally/ moves through around 15z-18z, W to E, respectively. HREF guidance shows favorable probabilities for at least 1.5" near the I-71 corridor stretching from about Wilmington, OH southwest toward Osgood, IN/Carrollton KY. Lesser amounts, potentially less than 1", are expected further to the SE toward Portsmouth, OH, with 1"-1.5" favored for EC IN and WC OH. It is important to note here that despite the slightly higher confidence in a bit more rain, the overall flood threat is expected to remain somewhat limited. The 14/30-day observed precip is running about 50%-75% of normal in the areas where the heaviest pcpn is favored, so do think that the ground will be /marginally/ receptive to 1.5"-2" for most spots. Even with this being said, some ponding of water in low-lying areas is expected merely because of the time of the year/lack of vegetation to help absorb rainwater. Have added mention of minor flooding threat in HWO for these areas, even with the uncertainties and questions regarding potential runoff issues. Widespread RA/TSRA will be ongoing just about everywhere around daybreak Tuesday, with rain quickly pushing E during the daytime morning hours. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/... As the rain ends from W to E Tuesday morning into early afternoon, a few fcst challenges continue. Most notably, there is a subtle signal for a 2-3 hour period immediately in the wake of the shield of pcpn for enhanced vertical mixing to translate some stronger winds from just off the sfc down to the ground. The stronger winds, courtesy of an H8 LLJ of 50+ kts and H9 LLJ of 40+ kts, will be with us past midnight through daybreak, but the saturated profile/slight inversion up until the precip ends should keep those winds just above the sfc. However, immediately following the pcpn, fcst soundings show a slightly more mixed LL environment evolving with slightly steeper LL lapse rates developing. While the mixing is not expected to be too deep, it really doesn`t need to be to bring some gusts to around 40kts down to the sfc. Have not added /that/ strong of wind straight into the fcst for now (have max wind gusts to round 32-34kts in fcst), but am discussing it here for awareness purposes here until the data/trends can be further monitored. It does seem that as the core of the LLJ peels off to the E by/past 17z-18z, the potential for gusts above 35kts will wane, although it will remain breezy (gusts to around 25kts) through the remainder of the afternoon in the open warm sector. Lastly, Tuesday will also be the warmest day of the week, with well-established warm advection -- and the trend toward a less rainy solution during at least the afternoon hours favoring warm conditions. However, some of the recent guidance has come in a bit /slower/ with the departure of the shield of rain (especially across the N/NE KY/SC OH), so there are questions of just how warm N/NE KY and the lower Scioto Valley will get on Tuesday if the rain persists past 1PM-2PM. Current fcsts may be too warm in these areas if the slower solution verifies, but expect that highs will get close to record values. Here are the current daily record highs for January 3. CVG -- 67 degrees -- 2004 and 1880 CMH -- 64 degrees -- 1950 and 1897 DAY -- 65 degrees -- 1897 Most of the afternoon, especially by mid-afternoon, is dry area-wide, with breezy/warm conditions expected. The actual front will still be hanging back well to the W of the ILN FA until it finally pushes through the area by late Wednesday morning. The convergence along the front will promote additional SCT/numerous showers along a relatively narrow corridor past midnight Tuesday into Wednesday morning before cooler/drier air filters in from the W by the afternoon once again. There may also be a few rumbles of thunder with this activity as well, but the LL thermodynamic environment should remain largely unfavorable for any notable severe potential. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... Rain showers will linger Wednesday behind a cold front. A light mix of rain and snow showers will be possible on Thursday as a closed upper low pushes in from the west, perhaps resulting in light snow accumulations. Dry weather is indicated for Friday under high pressure stretching from the Gulf Coast to the Ohio Valley. The next area of low pressure is forecast to bring a chance for rain and snow showers Saturday into Sunday, with light snow accumulations again possible. High pressure and dry air return on Monday. After a mild start in the 50s and 60s on Wednesday, a cooling trend behind the front will drop temperatures through the 40s on Thursday. Highs for Friday through Monday will hover around 40, a few degrees above normal winter highs. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... No major changes for the busy TAF period. CIGs are all MVFR at the time of this writing, but IFR restrictions are expected to return to local sites between 00-01Z. Expect ISO/SCT SHRA to move from SSW to NNE to around KCVG/KLUK by around 03z or so. This initial scattered activity will be well out in front/ahead of the main shield of steady/heavy rain and embedded TS, which will move in from the SW into the Tri- State by 06z. This initial round of RA/TSRA will quickly overspread the remaining local sites by 08z or so and persist through about 15z before the back edge of the pcpn clears from W to E. While there may be brief breaks in the RA/TSRA during this time, expect that most terminals will have a ~8 hour period of nearly steady RA, with embedded TS (TS favored for wrn sites of KDAY/KCVG/KLUK/KILN). The steady rain will lead to MVFR/IFR VSBYs coincident with the heaviest pcpn as CIGs go IFR to LIFR. Rain will end from W to E between about 14z-16z, with a brief period of gusty winds expected in the immediate wake of the pcpn. SSW winds of 15-20kts, with gusts to 30-35kts, will be possible mid/late morning (especially for KILN/KDAY/KCMH/KLCK), but may only persist for a few hours before trending back down again to 15kts with gusts to 20-25kts by the end of the period. Provided a window for SCT CIGs Tuesday 18-00Z for most sites due to lower confidence in MVFR conditions behind the wet conditions. Beyond 00Z WED, a cold front brings another chance for MVFR CIGs and VIS along with a chance for thunderstorms. For the CVG TAF, held off on mention due to lower confidence coverage. OUTLOOK...MVFR CIGs and VSBYs are likely again Tuesday night into Wednesday morning, along with a slight chance for thunderstorms. MVFR conditions are possible again on Thursday into Friday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...Dense Fog Advisory until 3 AM EST Tuesday for OHZ026-034-035- 042>044. KY...None. IN...None. && $$ SYNOPSIS...KC NEAR TERM...McGinnis SHORT TERM...KC LONG TERM...Coniglio AVIATION...KC/McGinnis
Area Forecast Discussion
National Weather Service Lincoln IL
844 PM CST Mon Jan 2 2023 .SYNOPSIS... Issued at 344 PM CST Mon Jan 2 2023 Increasing shower activity and even milder temperatures will spread across central Illinois overnight as a warm front crosses the area. Areas of fog, some of it dense, will accompany the front, along with scattered thunderstorms. Record warmth is possible tonight into Tuesday behind this front, with lows tonight only in the upper 40s and 50s, and highs Tuesday in the 60s. Heavy rainfall is possible mainly from around I-70 southward where 1 to 2 inches are possible through Tuesday morning. && .UPDATE... Issued at 842 PM CST Mon Jan 2 2023 Rain is beginning to move into southern portions of the forecast area and will lift north across the remainder of central Illinois through the evening, with the entire forecast area including the I-74 corridor expecting to see rain by 10pm or 11pm. Latest RAP shows 300-500 J/kg MUCAPE on the nose of a broad low level jet that will continue to support at least isolated embedded storms tonight, though with instability rooted around 850mb or so, the severe threat appears quite low. Meanwhile, dense fog persists particularly across east central Illinois. This should gradually improve from the south this evening and overnight as the warm front lifts north and winds turn southerly within the warm sector. That said, the front is moving slowly, and wouldn`t be suprised if there need to be adjustments in time or placement of the Dense Fog Advisory, especially near the I-74 corridor overnight. Will continue to monitor trends closely for any needed headline adjustments. && .SHORT TERM...(This evening through Tuesday) ISSUED AT 344 PM CST Mon Jan 2 2023 A complex warm frontal zone remains west-east across central IL this afternoon, with pervasive low cloud cover and areas of fog over most of the area, locally dense near I-74 east of Bloomington where some subtle convergence has been noted. The primary warm front appears to be developing just south of the forecast area where southerly winds and upper 50s to lower 60s dewpoints are noted. The warm front should start to move northward overnight, sweeping across the area from late evening south of I-70 to early morning at I-74. A few hundred J/kg elevated CAPE and strong shear will develop ahead of the warm front for scattered thunderstorms, but at this time the severe weather threat looks to be minimal with thunderstorms diminishing behind the warm front and a pre-cold frontal squall line likely passing by to the south of central/southeast IL. Nevertheless, convective trends will have to be monitored. A dry slot will push into central IL during the day Tuesday, diminishing precip chances and partially clearing skies, especially in west central IL. Forecast soundings indicate several hundred J/kg CAPE developing again Tuesday afternoon and evening ahead of the cold front, but a strong cap could prevent any deep convection from developing in this instability. Will have to monitor this for a threat of severe weather Tuesday afternoon and evening, mainly east-central and southeast IL. The cold front should finally cross the area Tuesday evening, bringing in a colder air mass and an end to any shower/thunderstorm activity for a time. Tonight, expect temperatures rising gradually through the night, with lows in record warm territory. However, the cold front Tuesday evening will likely prevent any daily record warm lows from being recorded. Highs on Tuesday, however, will be eligible for record, however, as highs rise into the 60s as central IL is squarely in the warm sector for a time. .LONG TERM...(Tuesday night through Monday) ISSUED AT 344 PM CST Mon Jan 2 2023 Cyclonic flow associated with the upper level low passing across the upper Midwest and central IL could promote some additional showers, mainly snow, Thursday in the northern half of the state. Amounts look to be spotty and generally light. Temperatures look to remain near normal for the remainder of the week behind Tuesday night`s front and the upper low. The next chance for precipitation for the extended forecast is over the weekend as a weak shortwave undercuts a large scale ridge over the central U.S. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 520 PM CST Mon Jan 2 2023 A warm front will lift north across the terminals this evening and overnight. Ahead of the front, IFR to VLIFR conditions will be in place due to low stratus and fog. Showers and storms will overspread the region late this evening lasting several hours. As the warm front lifts north of the terminals, east winds will veer to the south, and eventually SSW midday Tuesday with gusts picking up into the low to mid 20 kt Tuesday afternoon. Visibility and ceilings will also improve south of the front with flight conditions returning to MVFR or VFR. && .ILX WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until midnight CST tonight for ILZ038-043>046. && $$ UPDATE...Deubelbeiss SYNOPSIS...37 SHORT TERM...37 LONG TERM...37 AVIATION...Deubelbeiss
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
624 PM CST Mon Jan 2 2023 ...New AVIATION... .DISCUSSION... Issued at 357 PM CST Mon Jan 2 2023 Tonight-Tuesday... Main focus remains on the severe weather potential across the region. Spoke of energy is progged to eject ENE into the Mid-W to Great Lakes tonight-Tues around the periphery of the subtropical ridge to the SE. Strong sfc cyclone will develop, with a deepening sfc low expected nearly or sub 1000mb moving out of the Plains into the Mid-W. With strong upper jet moving across the Plains & into the Ozarks, increasingly favorable jet dynamics, diffluence/right entrance region of upper jet will propagate near the region tonight through Tues. There is increasingly favorable conditions for severe storms, but decreased confidence in recent CAM guidance for some of the more organized aftn convection & even significant & organized QLCS. With more recent runs of the HRRR adding more uncertainty on organization of any convective line sweeping in, confidence in strong tornadoes has lowered some. There remains the best potential for strong LLJ & clockwise curved hodographs with more sweeping wind profiles into the overnight hours. If a more semi-organized QLCS can develop to the W this aftn & spread E into the evening & persist, all modes of severe weather are possible, including tornadoes, damaging winds up to 70mph & some hail. As the cold front swings to the E, expect increased ascent & redevelopment of storms in E-SE MS. This area is where the "Enhanced" Risk was added earlier. After earlier collaboration with SPC, keeping this as is. However, wind profiles become to veer into the early aftn hours, limiting strong tornado potential. Definitely can`t rule it out further E-NE, especially closer to the MS/AL state line, as storms will initiate in SE MS in the I-59 corridor & spread ENE. After this initial round of storms Tues move out by mid-aftn Tues, some increased lapse rates, but more veered wind profiles/deep shear will support some large hail up to golf ball size. Main adjustments to the going graphic were to break it up to two, with one for first round late tonight through early Tues & the second round into Tues. Timing is tricky, if a QLCS develops early & persists, it could go later into the night. Confidence is increasing that not much in the way of aftn convection will develop & will be focused more after midnight in the NW Delta. This line of storms should weaken before redevelopment by mid- morning through late aftn-evening. Flash flooding is also another caveat, but there is continued support for heavy rain probs in the Delta & now increased potential into SE MS for the area of redevelopment. This is all dependent on actual evolution of organized convection, so if recent trends of HRRR are correct, could decrease potential in the NW Delta. For now, there remains potential for heavy rain of 2-4" with locally higher amounts to 6" in the NW Delta, where the Flash Flood Watch remains in effect. Can`t rule out some needed adjustments in SE MS where HREF ensemble neighborhood probs > 3" have increased & localized prob match mean values have bumped up to nearly +2-4". Coordinated some increase in QPF for SE MS, but if trends continue, another area of increased messaging of flash flooding potential may be needed or more focus may turn to this. Lastly, strong low-level jet & tightening pressure gradient of +5mb is expected, leading to sustained winds up to 25mph, with brief gusts up to 35-40mph, mainly NW of a line from SW MS into Jackson Metro up to Hwy 45 just S of the Golden Triangle. There is potential for some of those higher gusts to 45mph in the Delta mainly from SE AR, NE LA & extreme NW MS. This area will have to evaluated for future updates for a later wind advisory, if confidence in sustained winds increases. Lows tonight will be much warmer due to clouds & storms around, mainly in the mid-upper 60s. Highs Tuesday will be warm into the mid 70s. /DC/ Tuesday Night through Monday... Ongoing convective activity is anticipated at the start of the period across central and eastern areas as the slow moving front maintains deep moisture convergence to support showers/storms. The final push of large scale ascent will occur during the Tue night period and will make the most of what deep moisture remains along the front with all activity exiting the area around midnight. Some of this activity could be strong to severe but really depends on what instability remains from earlier activity. PoPs and weather grids will reflect the latest timing and exit of this activity. On Wednesday, mid level dry slot will punch into the area putting an end to any precip potential. Additionally, large scale mid/upper low will close off and slow its eastward progression. The result will be not much of a cold frontal push in the lower levels. As a result, WSW winds will exist and allow for a decent warm up Wed with 67-75 the more likely MaxT range. The cold air advection associated with the main part of the cold front will arrive later Wednesday night into Thursday bring in cooler and more seasonal conditions. The coolest period will be Friday morning when the surface high is over the region and radiational cooling will be maximized. Much of the area (esp N half) should reach freezing with other locations getting close. By the weekend, look for a steady moderation as a short wave approaches the region. This will allow for return flow to develop and bring some precip chances. There remains uncertainty in how this wave and other features will evolve. The result is lower confidence in any timing of precip for the area. If the wave is stronger, then better moisture return will occur and precip is more likely to develop later Saturday into Sunday. If weaker, then some moistening will happen, but it would be more likely the next wave will make the most of the moisture and precip would have better chances sometime Sunday into Monday. Overall, lower type chances will exist in the forecast to cover all of this until details can get ironed out. /CME/ .AVIATION...Rain moving in and steadily moistening the column which is going to gradually lower the ceilings. This will take some time, but we should see MVFR ceilings begin 20-23z (W to E) then be prevailing across all sites by 00-04z. We will then trend to see IFR by tonight and linger those conditions into early Tue. Much of this will be driven by precip and then linger as some precip moves out. Steady improving conditions look to take place after 18z Tue, so anticipate that trend in future forecasts. /CME/ && .AVIATION... (00Z TAFS) Issued at 610 PM CST Mon Jan 2 2023 Southerly winds will occasionally be gusty through this evening and overnight, with isolated SHRA at times. MVFR ceilings will become more common by 06Z Tuesday, with increasing chances for SHRA and TSRA affecting the TAF sites between 12Z and 20Z. /NF/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 67 75 53 71 / 40 100 40 0 Meridian 66 75 56 70 / 40 100 70 0 Vicksburg 66 76 50 68 / 70 100 30 0 Hattiesburg 67 75 58 73 / 40 100 70 0 Natchez 66 75 53 70 / 60 100 30 0 Greenville 64 73 50 65 / 100 90 10 0 Greenwood 66 73 52 68 / 80 100 30 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Flood Watch from midnight CST tonight through Tuesday morning for MSZ018-019-034-040-041. LA...Flood Watch from midnight CST tonight through Tuesday morning for LAZ007>009-015. AR...Flood Watch from midnight CST tonight through Tuesday morning for ARZ074-075. && $$ DC/CME/NF
National Weather Service Jackson KY
1040 PM EST Mon Jan 2 2023 .UPDATE... Issued at 1040 PM EST MON JAN 2 2023 First area of showers with embedded thunder is lifting northeast across Central Kentucky at update time, clipping the western edges of Pulaski. Rockcastle, Jackson and Estill counties in the process. As this activity moves northeast, look for it to move into the counties along and north of I-64 within the next hour or less and persist for at least a couple hours at most locations. Thereafter, expect a brief lull before another area of showers, presently organizing SSW of Bowling Green, likely follows a similar track, reaching Montgomery County around 2 AM. These rounds of showers will make for a wet night near/north of I-64. Southeast of I-64, a passing shower or rumble of thunder cannot be ruled out but most of the night will be dry. UPDATE Issued at 659 PM EST MON JAN 2 2023 Much of the area is dry this evening, just a few light showers linger along and north of I-64. A more substantial area of showers with embedded thunder is lifting northeast from the Western Tennessee Valley and will likely brush locations near and north of the I-64 corridor after 10 PM. To the southeast of I-64, there is a chance for a passing shower or even a rumble of thunder but most of the night should remain dry. No big forecast changes with this update other than to blend in the most recent obs and PoP trends. && .SHORT TERM...(This evening through Tuesday night) Issued at 346 PM EST MON JAN 2 2023 The afternoon surface analysis shows quasi-stationary boundary stretching from the the Panhandle of Texas to the Ohio Valley. High pressure remains posted up in the SE US in southern GA and eastern NC areas. In the mid and upper levels, ridging is arcing from the Ohio Valley to the Northern Plains. Some moisture convergence along and ahead of this boundary (noted along the nosing PWAT values) is helping to develop a few rain showers that have mainly been tracking to area north of the Mountain Parkway this afternoon. This will remain the story through the afternoon. Tonight, an upper level low will eject out of the SW US into the Plains and help to strengthen a baroclinic zone to our west. This will also lead to a deepening surface low that will track toward the Upper Mississippi River Valley. The increasing jets will certainly be felt with broad 850mb jet noted to increase across the Lower Ohio Valley. This will help to increase PoPs toward the Ohio River where greatest threat will be later tonight, with the lesser slight PoPs in the SE parts of eastern Kentucky. This low level jet will also eventually help to increase surface wind gust toward dawn in the 20 to 30 mph range toward dawn. This will lead to an unorthodox temperature curve, with the valleys initially dropping toward 50 degrees and likely warming a few degrees toward dawn Tuesday. Tuesday, the broad jet will continue to push northeast and diminish through the day, as the surface boundary slowly progresses east. The initial jet will be more southerly promoting downslope flow in the SE parts of eastern Kentucky, but these do veer toward the southwest through the day helping to increase moisture area wide. This combined with upper level divergence will help promote increased chances of showers and thunderstorms through the day. Also, fairly high PWATs are noted for this time of year given the ample moisture transport from the jet energy. However, ample convection toward the Gulf Coast also leaves a question mark on how much of that gets robbed from that area of convection. Right now, the 12Z HRRR is most aggressive with QPF from many of the other CAMs which shows a 2-3 inch swath across central Kentucky from 12Z to 18Z Tuesday, but lesser amounts over most of eastern Kentucky. Other CAM solutions and other forecast systems are less aggressive with the QPF overall. Either way WPC has kept us in a marginal for D2 ERO, and think that is a good call given some uncertainties in moisture and just how robust convection will be. Despite the cloud cover, strong southerly flow will certainly aid in well above normal temperatures with highs near 70s for most locations. Tuesday night, another slug of moisture and associated QPF is possible as the boundary approaches and we see another uptick in the low level jet. The is accompanied by increasing divergence aloft from a right exit region of an increasing 300mb jet. This will lead to yet another round of showers and thunderstorms by Tuesday evening into the night. The QPF seems to be most centered across the Cumberland Valley region, but still looking at perhaps a half an inch or less in most cases. Given the southerly flow and cloud cover overnight lows will be mild, with most locations in the upper 50s. .LONG TERM...(Wednesday through Monday) Issued at 435 PM EST MON JAN 2 2023 Key Points: * After several days of above normal temperatures, they return to near normal levels after a cold front moves through the area Wednesday. * A disturbance could provide another round of weather for portions of eastern Kentucky late in the week or next weekend. At this time, confidence is very low regarding the track, timing, and evolution of the late week...or possibly weekend system. Showers, and a even chance of thunderstorms will gradually dissipate through the day Wednesday as energy rounding the base and eastern periphery of a parent low (aloft) over the Upper Midwest passes to our northeast and out of the region by Wednesday evening. The pattern aloft then becomes less amplified, more zonal, and somewhat disorganized thereafter, leading to a much lower confidence in the latter half of the extended package. Sensible weather features a mid-week cold front that will provide the focus for the potential of lingering thunderstorms through the day Wednesday as the surface front exits to our east late Wednesday. Overall the chance for thunderstorms on Wednesday is conditional with only about 500 J/kg MUCAPE to work with but ample effective shear of 40-50 kts. Much will depend on how quickly the surface front moves through as well convergence along the boundary, which weakens through the day as upper level support outruns the surface feature. Cooler air (versus cold as the air mass originates from the Pacific) will settle across the region behind the front, bringing average temperatures back down into the 40s for highs and mid 20s to mid 30s for lows for the remainder of the forecast. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 659 PM EST MON JAN 2 2023 At the start of the TAF cycle, VFR ceilings prevailed except for MVFR near and north of I-64. Most sites should see VFR prevailing through the night. An approaching frontal boundary will bring the rising shower chances overnight, especially near and north of I-64. A VCTS cannot be ruled out at SYM. Winds will become southerly tonight in the 5 to 10 knot range with higher gusts. Just above the surface, a low level jet will increase through the night and lead to a period of LLWS through 14 to 17z before mixing increases on Tuesday morning. Southwesterly winds will become gusty at 20 to 30 knots on Tuesday. An area/line of showers is expected to attend a prefrontal trough during the midday/early afternoon and could bring strong, erratic winds, reduced visibilities and embedded thunder to all sites. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...GEERTSON SHORT TERM...DJ LONG TERM...RAY AVIATION...GEERTSON
Area Forecast Discussion...Updated
National Weather Service Saint Louis MO
939 PM CST Mon Jan 2 2023 .UPDATE... Issued at 938 PM CST Mon Jan 2 2023 As of 9 PM, while additional thunderstorms are expected across much the area through the remainder of the night, the probability that any of these storms will become strong or severe locally appears to be diminishing. While more organized and stronger convection developed across far southeast Missouri earlier this evening, widespread stratiform rain along with embedded and elevated convective elements were the dominating precipitation type locally. Some of this activity remains ongoing in these areas, along with portions of central Missouri, and very little surface-based instability is present locally. While some instability recovery will be possible overnight as the low-level jet surges northward, particularly across central Missouri, this is likely to be very limited at this point. Regardless, at least a marginal amount of elevated instability (up to ~500 J/kg MUCAPE) is expected to spread eastward through the night, providing enough instability to support scattered to numerous thunderstorms across much of the area. In fact, thunderstorms are already ongoing upstream in western Missouri, and this activity is expected to steadily spread east through the night. While the potential for these storms to become strong or severe appears to be limited in our area, we can`t completely rule out an occasional strong wind gust during the overnight hours, particularly in central Missouri if some semblance of surface-based instability can redevelop. Storms will likely approach the eastern edge of our area (south- central Illinois) by daybreak, with dry conditions filling in behind. BRC && .SHORT TERM... (Through Late Tuesday Night) Issued at 157 PM CST Mon Jan 2 2023 Key Message: Confidence continues to increase in a few severe thunderstorms occurring this evening. Across southeastern Missouri, damaging winds and a tornado or two are the main concerns. While strong to severe thunderstorms are possible across central Missouri and southwest Illinois and will be capable of quarter sized hail and damaging winds. The mid-level trough driving the next 24 hours of sensible weather is exiting the Four Corners region, strengthening a surface low off the lee side of the Rockies in response. A warm front is currently laid out through central Missouri and will continue to move northward as the surface low strengthens and moves northeast into the forecast area this evening. Southerly flow south of the front is advecting warm, moist, unstable air northward, pushing dewpoints in southern Missouri into the low 60s. The 20Z RAP analysis is indicating 200-400 J/kg of elevated MUCAPE across this area. As the afternoon progresses these values are expected to continue to increase and surge northward in lockstep with the advancing warm front. The HREF ensemble mean indicates 500-750 J/kg of MUCAPE making it as far north as the I-70 corridor. The NAM is by far the most bullish of the operational models, indicating over 1000 J/kg of MUCAPE by 00Z across much of the forecast area. While some operational models are showing more conservative amounts of instability (100-200 J/kg MUCAPE) building into the forecast area, confidence is increasing that higher amounts of instability will be present this evening, particularly across southeast Missouri where clearing is boosting instability. The first round of showers and thunderstorms will form along the southwesterly LLJ this afternoon and evening, mainly across southeast Missouri and southern Illinois. The strong dynamics advertised with the approaching system (50% chance effective bulk shear greater than 30 kts, 30-50 kts 0-3 km shear) will be able to organize thunderstorms into initially discrete convection this evening. HREF SRH values increase during the 00-06Z period across southeast Missouri from 150 to near 300 m2/s2, increasing the risk for tornado development. Damaging winds and quarter sized hail are also a concern with any storms that become strong to severe. The second round of showers and thunderstorms will move through the area during the late evening and overnight along the initial cold front associated with the occluding low. Initially discrete convection will be capable of producing quarter sized hail, particularly across central and southeast Missouri where lapse rates will be near 6-8 C/km this evening. As this convection encounters the southwestward LLJ it will evolve into mixed mode and broken line segments, and the associated threats will transition to mainly damaging winds and QLCS tornados. The front and associated convection will exit the forecast area by tomorrow morning. Dry air advection will move into the area in the low to mid-levels, helping to clear out lingering precipitation for the morning. MRM .LONG TERM... (Wednesday through Next Monday) Issued at 157 PM CST Mon Jan 2 2023 The occluded low will push northeast of the forecast area Tuesday. The southwesterly flow behind the first boundary will allow for significant warming on Tuesday, pushing temperatures into the 60s area wide. Record high temperatures at KUIN and KSTL have a solid chance of being broken (see Climate Section below). Instability will rebound on Tuesday across portions of southeast Missouri and southern Illinois along robust southwesterly flow. A mid-level shortwave and strong LLJ could produce an isolated shower or thunderstorm Tuesday afternoon, so have kept PoPs in during this period. A second, more robust cold front associated with the occluded low will move through the region Wednesday morning, bringing northwesterly winds and a return to normal temperatures for the mid-week period. By the end of the week northwesterly mid and low-level flow will become southwesterly ahead of an approaching ridge. Temperatures will warm slightly in response Friday and Saturday. Ensemble guidance shows the mid-level pattern diverging in solution over the weekend, but generally becoming more active. There is the potential for a weak low to move through the forecast region over the weekend, but the lack of moisture return ahead of the low and the uncertainty in the mid-level pattern is keeping confidence in this occurring low. MRM && .AVIATION... (For the 00z TAFs through 00z Tuesday Evening) Issued at 506 PM CST Mon Jan 2 2023 After a brief improvement during the afternoon, LIFR fog and stratus has built back into the region and is expected to continue through the evening and into the morning hours. Showers and thunderstorms will move through the forecast area this evening and overnight, though confidence in the location of thunderstorms remains medium, so have left VCTS in the TAFs for now. Ceilings are expected to improve to at least IFR conditions with the onset of precipitation, if not MVFR or VFR conditions, though confidence in significant improvement is low. IFR/LIFR visibility is expected to continue throughout the evening, improving after precipitation exits the area. Precipitation will exit the terminals overnight and through the early morning hours. Conditions are expected to improve to VFR flight conditions tomorrow morning as dry air makes it ways into the region and clears visibility and ceilings. Winds will become southwesterly and gusty behind the precipitation tonight, gusting into the upper teens to low 20s tomorrow. MRM && .CLIMATE... Issued at 157 PM CST Mon Jan 2 2023 January 3, 2023 Record High Temperatures STL: 68 (1939) COU: 71 (1997) UIN: 63 (1998) && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Morristown TN
929 PM EST Mon Jan 2 2023 ...New UPDATE... .UPDATE... Issued at 923 PM EST Mon Jan 2 2023 Area of weak convection moving northward into the area not handled well by most of the CAMS, but the 4 km NAM does show something at least similar and lifts it north across the area. Will tweak PoPs/WX to better align with this solution and latest radar trends. Otherwise, will tweak some min temps down especially north/central and make some other minor adjustments to dew points and sky with this update. && .SHORT TERM... (This evening through Tuesday night) Issued at 315 PM EST Mon Jan 2 2023 Key Messages: 1. A strong storm system will affect the area tomorrow and tomorrow night, bringing widespread rainfall, gusty winds, and a few thunderstorms, some of which could be strong to severe. The current SPC day 2 outlook has a slight risk from the Cumberland Plateau down into the southern TN Valley. This the area of greatest concern where isolated damaging wind gusts and an isolated weak tornado are possible. 2. Strong winds are expected in the Tennessee mountains and nearby foothills early Tuesday morning through afternoon. A Wind Advisory has replaced the High Wind Watch that was previously in effect. Discussion: Overview: Tonight, a strong upper jet will begin moving into the area as a deep low pressure center moves through the central/northern Great Plains. Upper level divergence and moisture increase through the night and a few light showers will be around as a result. With high pressure to our east, the pressure gradient tightens through the night and into Tuesday as the low pressure center and broad upper trough draw closer to the region. The 850mb jet ramps up to 45 to 55kts by Tuesday morning and is in place through the afternoon hours, thus the need for a wind advisory for the east TN mountains. POPs rapidly increase from slight chance/chance Tuesday morning to Likely/Categorical by late Tuesday afternoon as a line of showers and storms approach the area. If you average the arrival time of the Hi-Res models, storms move into our area some time between 17Z and 19Z tomorrow afternoon. Showers and storms will then move across the area and exit east during the evening hours. We then get a short break before a second wave of showers and potential storms move through late Tuesday night into Wednesday morning. See the following sections below for more details. Wind: The High Wind Watch that was previously in effect has been replaced by a Wind Advisory. The Advisory is in effect from 4 AM EST Tuesday morning through 4 PM Tuesday afternoon. Most guidance shows max wind gusts ranging from 45 to 60 mph. So while some areas may hit warning criteria, like Cove Mountain, I expect the majority of the areas within the advisory to remain below warning criteria with wind gusts between 45 to 55 mph. The stronger gusts subside Tuesday afternoon into Tuesday evening but models show the 850mb jet restrengthening after midnight, back to 40 to 50kts, and lasting into Wednesday morning. It`s likely that an additional Wind Advisory will be needed to cover late Tuesday night into Wednesday morning. Did not want to stretch the current Wind Advisory out that long since there will be a period where winds won`t meet criteria. Lastly, while there is low-end probability for some minor mountain wave enhancement, do not see this being a classic mountain wave event as the 850mb wind are mostly parallel to the terrain of the Appalachians. Rainfall: QPF continues to gradually decrease, as has been the trend over the last few days. Latest storm total QPF generally has 1 to 2" of precip across the area, other than northeast TN and southwest VA where only up to 1" is expected. These amounts will not pose a flooding risk as the latest 6 hr FFG values ranges from 2 to 3" with 1 hour FFG amounts similar to our storm total QPF, which is over a 24 to 36 hour period. So other than some minor ponding of low lying areas as the main line of showers and storms moves through, don`t anticipate any flooding problems. Severe: As with the last several forecasts the severe threat, unfortunately, still remains uncertain across our area and is very much a conditional threat. The main item of uncertainty has always been how much instability would develop across our area. Latest HREF, HRRR, and RAP runs continue to show minor surface based instability across the area, generally ranging between 100 and 300 J/kg. If these amounts materialize, we will have a threat for a few strong to severe storms as moderate/high shear will be in place across the area. The main areas of concern will be across the Cumberland Plateau and southward into the southern TN Valley, which line up with the current SPC day 2 outlook. If the instability develops, then isolated damaging wind gusts and a weak isolated tornado are possible. If the instability does not develop, the threat substantially lowers. If we see more instability than models are showing, then the threat increases. The main concern for areas outside of the slight risk, from central TN Valley and east, will be isolated damaging wind gusts. These area are very unlikely to develop enough instability to warrant a tornado threat. As mentioned previously, storms move in between 17Z and 19Z and continue into the evening hours. We will then see a break before an additional wave of showers and potential storms moves in Tuesday night along the cold front. While the environment will still have shear, instability chances will be lower. So while the main focus should still be on afternoon activity we will still have to keep an eye on this second wave as well. && .LONG TERM... (Wednesday through next Monday) Issued at 315 PM EST Mon Jan 2 2023 Key Messages: 1. Showers and possibly a few thunderstorms will exit west to east on Wednesday with most places remaining dry until chances for precipitation return by the weekend. 2. Temperatures will cool to near normal on Thursday and continue through the weekend. Wednesday through Friday At the start of the period, a trough will be located just to our west with a low pressure system located near the Great Lakes. Its associated cold front will be approaching the area with lingering convection expected to be ongoing. During this timeframe, some lingering instability is expected, which will support potential of a few thunderstorms. With the better dynamics and forcing having moved eastward, the concern for strong/severe storms is limited, in addition to coverage and additional rainfall totals. Additionally, the strengthened low-level jet is expected to be gradually weakening through the day. The frontal boundary will move through the area by the end of the day, leading to a gradually drier and cooler pattern. On Thursday, strong upper troughing and low-level CAA will take place, leading to temperatures dropping to near normal. With the height falls and some lingering moisture, a few light showers are possible in northeastern portions of the area by Thursday night. Some light rain/snow mix is possible in the higher elevations but looks unlikely to even be measurable. By Friday, high pressure will lead to subsidence and clearing skies. Saturday through Monday Heading into the weekend, flow will become more quasi-zonal with a strong 120+ kt jet approaching from the west. With the region moving into the left-exit region of this jet and varied indications for weak cyclogenesis, an NBM return of PoPs will be kept in the forecast. There is still a lot of uncertainty as to how cold the lower levels will be locally, but there is potential for mixed precipitation, especially in the higher elevations. At this time, the consensus keeps the region too warm for frozen precipitation, but it is still indicated in some deterministic/ensemble guidance. && .AVIATION... (00Z TAFS) Issued at 520 PM EST Mon Jan 2 2023 Showers will be moving in during the period first at CHA but will likely hold off at TYS/TRI until late in the period. At CHA, low cigs will likely keep things mainly MVFR to IFR, but expect VFR conditions for much of the period at TYS/TRI. However, at TRI enough clearing may occur tonight for fog development and, if it occurs, how significant it may be is uncertain. Will include MVFR vsby for several hours tonight at TRI for now. Winds will start out light but will become gusty from the south and southwest late in the period. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 59 70 61 68 / 50 100 100 40 Knoxville McGhee Tyson Airport, TN 51 71 59 67 / 30 90 100 70 Oak Ridge, TN 55 70 59 67 / 30 90 100 70 Tri Cities Airport, TN 47 71 56 66 / 10 60 90 90 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...Wind Advisory from 4 AM to 4 PM EST Tuesday for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...NONE. && $$ SHORT TERM...SR LONG TERM....BW AVIATION...
Area Forecast Discussion
National Weather Service Topeka KS
829 PM CST Mon Jan 2 2023 .UPDATE... Issued at 829 PM CST Mon Jan 2 2023 The surface low is beginning to pass to the east of the forecast area with the initial shortwave and associated convection moving into MO. There may still be some light showers this evening with the upper low still to the west. But the moisture and instability axis should continue shifting east with the surface low. So the risk for severe storms is expected to decrease through the rest of this evening. Focus remains on potential for fog redeveloping on the back side of the system and most guidance including the 02Z RAP show an axis of restricted visibilities to the west of the surface low track by 05Z or 06Z. So plan to keep the fog advisory going for now to see if the fog develops as forecast. UPDATE Issued at 528 PM CST Mon Jan 2 2023 Latest guidance from the RAP and NAM show the track of the surface low basically along the turnpike and into northwest MO. There is a growing consensus for the boundary layer to remain saturated along and just west of the surface low track through a good portion of the night until winds pick up and mixing increases on the back side of the low. Because of this have extended the dense fog advisory through the night expecting periods of reduced visibilities. It may not be a quarter of a mile the whole night, especially if showers pass overhead, but the potential is there. && .DISCUSSION... Issued at 255 PM CST Mon Jan 2 2023 Key Points: - Dense fog continuing this afternoon in portions of east central and northeast KS - Strong to severe storms possible late this afternoon into this evening, particularly along and south of I-70 - Up and down temperatures the rest of the week while staying dry Upper low continues to spin over the Four Corners region while slowly traversing eastward with southerly flow aloft advecting warmth and moisture northward. At the surface, low pressure has been developing over the TX panhandle with a warm front extending through OK and KS through central MO. As of 20Z, the boundary is moving into southern Anderson and Coffey counties with temps in the 60s and 70s and dew points near 60 just to the south. To the north of that boundary where the warm front gradually slopes into the cold air, an inversion has kept much of the area socked into fog all day. Will hold onto the Dense Fog Advisory this afternoon, as this area has seen more consistent visibilities down to a quarter mile, although other locations remain foggy as well. Western portions of the advisory may be cancelled early as rain and storms move into the area from south central KS, but will continue to monitor. The first batch of showers and storms currently in central KS should remain sub-severe as it moves across the area mid to late afternoon. The more potentially concerning activity will be the storms that develop in northern OK and south central KS, which move northeast across the CWA late this afternoon through the evening. Still expect that most of this should remain elevated as anything surface-based will be hard to come by north of the warm front where the boundary layer has that inversion in place. HREF data and SPC mesoanalysis indicate 500-1000 J/kg of MUCAPE with this activity, and even though this wouldn`t tap into the shear at the lowest levels, there would still be enough to support large hail with any strong updrafts that can get going. The main challenge in the short-term will be how far north the warm front can move this evening. CAMs have the sfc low pressure progged to move through south central and northeast KS this evening and into southeast NE by early Tuesday. At this time, areas along and south of I-35 would stand the best chance of any surface- based storms south of the front, which provides a better chance for damaging winds in addition to the hail, and could provide an outside chance for a tornado threat. While this is a low-probability scenario, it is one that should be watched closely. As the sfc low pushes into NE, rain should end for most if not all of the area overnight. Most model guidance has wrap-around moisture on the back side of the system remaining north of the area, but still can`t completely rule out some deformation precip in north central KS early Tuesday morning. If that occurs, temperature profiles should be cold enough to support snow, but thinking little more than flurries or brief light snow with no impacts anticipated. The upper low becomes cut off and stalls in the Upper Midwest Tuesday and Wednesday before finally starting to move east on Thursday as the next trough moves onto the Pacific shore. CAA brings highs back down into the 30s and 40s through Thursday. On Friday, low-amplitude ridging results in stronger WAA to bring a quick warm- up into the 40s area-wide. Then another quick-moving system brings another front through the area on Saturday to bring highs back to the 30s, although the better moisture appears to remain south at this time. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 440 PM CST Mon Jan 2 2023 Terminals look to be stuck in the crud at least through the night as the surface low lifts through northeast KS. The RAP and NAM have trended in keeping the boundary layer saturated on the back side of the low track with VLIFR conditions persisting. Towards 12Z as the sfc low moves into southern IA, the pressure gradient should increase allowing for the low clouds to lift. CIGS may lift above 3 KFT Tuesday afternoon. CAMS all bring a progressive wave of convection through the terminals this evening. So it looks like there will be a window for a few hours with TSRA as they lift north with the system. && .TOP WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 4 AM CST Tuesday for KSZ011-012-022>024- 026-035>040-054-055. && $$ UPDATE...Wolters DISCUSSION...Picha AVIATION...Wolters
Area Forecast Discussion For Western SD and Northeastern WY
National Weather Service Rapid City SD
749 PM MST Mon Jan 2 2023 .UPDATE... Issued at 743 PM MST Mon Jan 2 2023 Latest IR loop showed lead deformation zone that lifted northwest into northeast WY/northwest SD has been cutoff from moisture with warming clouds tops and increasing visibilities per webcams/surface observations. Latest HRRR in line with observational trends, and it has minor additional accumulations along the northwest strip of Winter Weather Advisory areas. Will drop advisories from Wright to Rapid City. Secondary, more powerful deformation zone taking shape across NE int south-central SD per water vapour/regional radar loop. Upper low over eastern WY had 110kt jet streak ahead of it which will force moderate/heavy snow from KIEN-KICR overnight, which is where strong frontogenesis in place. Forecast in good shape there. Updates out shortly. && .DISCUSSION...(This Evening Through Monday) Issued at 135 PM MST Mon Jan 2 2023 Vigorous upper trough and sfc low crossing the Plains this afternoon. Weaker lead trough is still supporting light snow across most of the region, with more persistent moderate to heavy snow ongoing across south central SD. Snowfall amounts have generally been mid-range adv levels (2-4 inches) across the the NW edge of this system, with dry air, warm temps, light snowfall rates all working against efficient snow accums. Generally 1-2 inches more expected on the backside of this system over the NW 2/3. Have trimmed the backside of the warning given above concerns, shifting to and adv on the NW edge of the system. The main upper trough will support very strong FGEN response over the NE panhandle into scentral SD, with very heavy snow still on track there. Still expecting totals of 1 to 2 feet from Mission to Winner and SE given strong LSA/FGEN couplet. Strongest LL FGEN is progged right over this location, with the heaviest snow expected just to the SE, which continues the SE trend of this system. Hence, the heaviest snow will likely occur in Neb into SE SD, just southeast of the FA. Breezy NW winds expected to develop over scentral SD tonight as the sfc low winds up, supporting areas of blowing and drifting snow there into Tues. Snow will end west to east starting later tonight, with most of western SD and NE WY expected to be snow free by mid Tue morning, except for scentral SD. Not much cold air behind this system with seasonal temps the remainder of next week and dry conditions until next weekend, when another trough is progged to cross the region, potentially bringing some light snow to the area Friday. && .AVIATION...(For the 00Z TAFS Through 00Z Tuesday Evening) Issued At 437 PM MST Mon Jan 2 2023 Widespread MVFR/IFR conditions expected through tonight. VFR conditions over far northwest SD early this evening will be replaced by IFR/LIFR stratus/fog overnight. Ongoing snow will also bring periods of IFR/LIFR conditions, especially from the Black Hills to KICR. Snow will taper off from west to east, beginning after 06-08z Tuesday across northeastern Wyoming and then over western SD Tuesday during the day. && .UNR WATCHES/WARNINGS/ADVISORIES... SD...Winter Storm Warning until 5 AM MST Tuesday for SDZ027-041>044. Winter Weather Advisory until 5 AM MST Tuesday for SDZ029>032- 074. Winter Storm Warning until noon CST Tuesday for SDZ046-047-049. WY...None. && $$ Update...Helgeson DISCUSSION...JC AVIATION...Helgeson
Area Forecast Discussion
National Weather Service Las Vegas NV
709 PM PST Mon Jan 2 2023 .SYNOPSIS...An active weather pattern continues this week with a quick hitting system moving over the area tonight through Tuesday morning followed by another potentially significant AR wave bringing heavy snow to the Sierra Wednesday night and Thursday. A dry period follows for Friday through Saturday morning before another system could bring more snow to the Sierra Saturday night into Sunday. && .UPDATE...After a quiet afternoon, we are starting to see the next system makes it`s way into the area this evening. TPW satellite imagery through the early evening showed a plume of moisture stretching into southern California ahead of a weak shortwave moving into central California. Based on water vapor satellite trends though, this system is not well organized as all the elements look disjointed and unimpressive. SNOTEL and webcam data, combined with radar and satellite trends, would suggest that precipitation has not yet made it into and over the Sierra ridgeline with all the precipitation so far remain on the western slopes towards the coastline. Further east, clouds draped over much of the Southwest US as mid to high level moisture streamed in ahead of the incoming system, but it remained dry through the evening. Winds in the western Mojave Desert have increased in response to the incoming system with gusts 35 to 35 MPH reported through the early evening, otherwise winds were light in most locations. As the airmass in place is slightly drier than yesterday, it is a few degrees cooler right now compared to this time yesterday despite the cloud cover. Based on trends and the latest hi-res model data, updated precipitation chances overnight to slow down the progression of precipitation eastward. The latest HRRR and HREF runs have limited model reflectivity spreading east through the first part. The Sierra precipitation chances remain mostly unchanged as they will intercept much of the moisture and see decent orographic forcing ahead of the wave, but the spill over will be slow and the development of precipitation in eastern San Bernardino County and southern Nevada will struggle as the main area of forcing will remain to the south. Precipitation will likely not begin impacting areas outside of the Sierra until after midnight. After midnight, forcing should increase across Nevada and western Arizona as the main shortwave digs into the region and moisture increases slightly as the moisture plume final moves further inland. However, it will be a fasted paced system once it makes it into NEvada and will quickly move into utah and western Arizona which will limit impacts as precipitation will be short lived as it moves quickly east. By Tuesday early morning, much of the precipitation should be ending in California and northern Nevada with the only remaining showers being in Mohave County. Rainfall totals will be unimpactful as moisture will not be as high as the previous system we saw this weekend and precipitation will move quickly. Snow levels will remain around 4000ft then increase to around 5000ft by Tuesday morning as the warmer moist air arrives. With limited QPF, warm overnight lows, and increasing snow levels, the only snow impacts should be in the Sierra where minor to low end moderate snow impacts are possible as 4 to 6 inches of snow is all that is expected out of this event. -Nickerson- && .PREVIOUS DISCUSSION...309 PM PST Mon Jan 2 2023 .DISCUSSION...Tonight through Thursday. A shortwave moving out of the eastern Pacific will move into central California later today and across our area tonight bringing an inch or two of snow to the upper Sierra slopes and 2-4 inches to the peaks by 6 am Tuesday. Elsewhere, increasing chances for light shower activity east of the Sierra generally after midnight tonight. Widespread rainfall amounts of a tenth or less but locally up to 0.25 inches - mainly in parts of Mohave County north of Kingman. Total snow amounts forecast for areas east of the Sierra include 1-2 inches in the Spring Mountains and 2-4 inches in the the higher terrain of Mohave County generally north of Kingman. As this system moves away from the area Tuesday night, models bring a weak shortwave across northern Nevada Tuesday evening but little if any impact is expected for our area. Shortwave ridging builds across the region on Wednesday as the next significant AR wave moves to the California coast. Initially with this wave, the brunt of moisture is directed into the northern Sierra with snowfall amounts in our portion of the Sierra forecast to be fairly light through 10 pm Wednesday evening. As the deeper moisture sinks southward and gets directed into the southern Sierra overnight Wednesday, upper forcing increases - creating conditions that are conducive for producing heavy snow and significant snow accumulations. Current forecast amounts and confidence levels justify issuing a WINTER STORM WATCH for the Sierra eastern slopes beginning at 10 pm Wednesday and running through 10 pm Thursday. This period, as currently forecast, would bring the highest impacts from accumulating snow and would better define when we expect winter storm conditions will be possible. Current snowfall amounts in the White Mountains are forecast to meet warning criteria as well and this area will be included in the watch. Outside of the Sierra and White Mtns, only minor impacts are expected with this system and are generally tied to slick road conditions and localized minor flooding issues. Friday through next Monday - Models have our area in between systems and dry Friday through Saturday morning. The next wave carrying AR moisture reaches the coast Saturday - increasing precipitation chances in the Sierra in the afternoon with chances persisting through Monday. East of the Sierra, the Owens Valley and White Mountains become the primary beneficiaries of higher rain and snow amounts, according to the latest forecasts, while other regions within our forecast area see only slight chances. Temperatures in this period are forecast to remain a little below normal and winds are forecast to be generally light. Looking ahead beyond next Monday, more AR action is forecast with significant snowfall possible in the Sierra. && .AVIATION...For Harry Reid...Thickening and lowering clouds this afternoon and especially after sunset will lead to a chance of light rain overnight into Tuesday morning. Rain could drag ceilings down to 5000 feet or even as low as 3000 feet. After the rain chances move out Tuesday morning, low confidence in the cloud forecast. Clouds could clear faster than forecast (more likely if rain does not affect the terminal), or lower clouds could linger for longer (more likely if rain affects the terminal). Not much confidence in the wind direction for Tuesday, but moderate to high confidence that speeds will remain at or below 10 knots. For the rest of southern Nevada, northwest Arizona and southeast California...Low clouds over Mohave, eastern Lincoln, and near the mountains of Clark County will persist through sunset. Ceilings of 3000-7000 feet will be common in these areas, with lower ceilings and terrain obscuration near mountains. High clouds will increase, thicken, and lower from west to east this afternoon through tonight. Chances for snow will begin near the Sierra crest around sunset, and chances for light rain in the deserts and snow in the mountains will spread from west to east tonight into Tuesday morning. Low ceilings and terrain obscuration can be expected in areas of precipitation. Conditions will briefly improve from west to east Tuesday. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION...Salmen AVIATION...Morgan For more forecast information...see us on our webpage: or follow us on Facebook and Twitter