Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/30/22

Area Forecast Discussion
National Weather Service Denver/Boulder CO
844 PM MST Tue Nov 29 2022 .UPDATE... Issued at 837 PM MST Tue Nov 29 2022 It`s much quieter across northeast Colorado compared to 24 hours ago. A few clouds, and perhaps a couple of light snow showers, are still located across some of the northern mountains, but should continue to dissipate overnight. It`s clear across most of the plains, though we`re starting to see some patchy fog develop over portions of Larimer county. Have added just a touch of patchy fog into Larimer/Weld counties where BUFKIT profiles suggest fog development over the next few hours. Otherwise, the only other notable change was to lower MinT`s tonight, as a few spots in the river valleys have already dropped below NBM 5th percentile values. I`m not sure we dropped them enough, but a few more spots will certainly fall below zero. Did ponder some Wind Chill Advisories, but it doesn`t look like we`ll have enough areal coverage across any zone along the far northeastern plains. Either way, it`s going to be chilly! && .SHORT TERM...(This evening through Wednesday) Issued at 237 PM MST Tue Nov 29 2022 Current GOES-16 satellite imagery shows mid level water vapor over the high country and weather station observations displays an agreement of temperatures reaching forecasted afternoon highs. Snow showers have begun tapering down overall but higher peaks will continue to see flurries through late afternoon. Any additional amounts will remain under an inch through this evening. 700mb temperatures HRRR and NAM trending near -15 to -18 across the region and it likely overnight lows will drop into the lower teens in the urban corridor, single digits for the foothills and plains, and several degrees below zero for the mountains and valleys. Overnight into Wednesday morning, QG fields are showing strong subsidence tonight meaning drier conditions. 500mb westerly winds are increasing as latest guidance suggest 70-80kt winds. This suggests a small mountain wave event for our foothills areas and mountains where wind gusts up to 35-45 mph is possible through the overnight hours. Thus, this forecast update includes an increase to winds. Model soundings indicate an inversion in the urban corridor should keep winds relatively weaker but would not be surprise if parts of the urban corridor such as Broomfield, Superior, and Arvada could receive gusts up to 35 mph briefly. Wednesday, a slight warm up is possible with temperatures barely above freezing for all areas above 10k ft and partly cloudy skies. .LONG TERM...(Wednesday night through Tuesday) Issued at 237 PM MST Tue Nov 29 2022 ...BOUTS OF MOUNTAIN SNOW AND WINDY AT TIMES... For Wednesday night and Thursday, southwest flow strengthens with gusty winds developing over the mountains. Low temperatures on Wednesday night will be a challenge, with sharp valley inversions but sufficient drainage winds combining with warm advection in/near the foothills and Palmer Divide. We cooled off the low spots a few more degrees with sharper inversions, while warming up the foothills/nearby plains a few more degrees from the existing forecast. Wouldn`t be at all surprised to see more sharpening needed as we head into the shorter term. For Thursday, a good warmup is expected with the strong warm advection and 700 mb temperatures rising to +3 to +5C across the plains. That would normally support highs well into the 60s, but there will be some lingering snow cover to offset especially along and north of the I-76 Corridor. That`s where we`ll keep it somewhat cooler, but again some sharpening in the forecast temperature gradient may be required as get into the closer term and have more details regarding snow cover and local wind patterns (expect a weak cyclone or at least a shear zone north of the Palmer Divide keeping it cooler to the north as well). South of that, it will likely be warmer than forecast. Our attention will then turn toward a rather potent shortwave moving across the Great Basin and Northern/Central Rockies Friday. While moisture increases late Thursday night and early Friday morning with snow developing in the mountains, it may be late Friday morning into Friday afternoon when significant impacts arrive for high Country travel in the North Central Colorado mountains and I-70/Summit County Corridor. That`s when strong cold advection arrives and joins forces with improving (but still westerly) orographics. The mid level flow is very strong with mountain top flow greater than 50 knots, so any period of heavier snow will likely produce significant travel impacts and blowing snow. Snow squalls will even be possible with the arrival of the mid level cold front/frontogenesis. We`ll also have to worry about high wind potential across the higher mountains, foothills, I-25 Corridor and portions of the plains. With 50+ knots at 700 mb, it won`t take much subsidence to get high winds spreading into the lower elevations. Best subsidence at this time behind the cold front stays just to our north, but something to watch especially considering the magnitude of the flow. Gradients also support near high wind forecasts. After that system, there should be a period of relatively tranquil weather Saturday before the next system arrives by late Sunday or Monday. Right now, ensembles are offering up a bit more troughiness with this shortwave, so a little better chance of some snow spilling onto the plains toward Monday. However, mountains are still most favored at this time for more accumulating snow and travel impacts. Temperature forecasts will remain difficult especially with rather strong warm advection between these fast moving shortwaves. Slight timing difference (also common in these fast moving progressive patterns) can also have large implications on realized temperatures. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 440 PM MST Tue Nov 29 2022 VFR through the TAF period. Winds are fairly weak and will remain light through tomorrow. Drainage flow is expected to establish tonight, turning more north/northwesterly at DEN Wednesday morning. Any lingering low clouds should diminish over the next couple of hours with no ceiling or visibility concerns anticipated. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Hiris SHORT TERM...AD LONG TERM...Barjenbruch AVIATION...Hiris
Area Forecast Discussion
National Weather Service Columbia SC
829 PM EST Tue Nov 29 2022 .SYNOPSIS... Showers and thunderstorms are expected across the area beginning late tonight through Wednesday as a cold front crosses the region. Rainfall amounts up to 1 inch possible and some gusty winds. Cool and dry conditions finish out the week before a warming pattern sets in for the weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Surface high pressure continues to retreat off the coast as a strong storm system approaches from the west. Air mass remains quite dry with PWATs around 0.5-0.7 inches but increasing southwesterly low level flow ahead of an approaching upper trough will rapidly increase the atmospheric moisture through the overnight hours. Regional radar already showing some showers pushing into the Upstate at this time. As these showers move into the Midlands they may weaken initially as they encounter the drier air but measurable rainfall is expected to arrive shortly after midnight with the highest rain chances pushing in as a convective line in the 10-12z time frame from the west. Instability is extremely low so the severe weather threat is also very low, however cannot rule out isolated thunderstorms. Temperatures have cooled quickly after sunset with some locations already approaching forecast lows so will need to adjust them a bit but clouds are moving in from the west and will stabilize temperatures for the remainder of the night. In fact, as winds increase later tonight temps may rise a bit through sunrise with better mixing and continued thickening cloud cover. Expect lows in the low to mid 50s. && .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/... Little change in the thinking for Wednesday`s cold front passage as a line of showers and isolated thunderstorms moves through. Synoptic forcing will generally remain to our north for much of the day with limited jet level dynamics nor impactful mid-level height falls. Instability will remain limited as strong warm advection from 850mb through 700mb overruns weak surface flow early Wednesday, along with the lack synoptic support aloft; the hi-res and GEFS members at most produce 100 J/kg of sfc based CAPE. So while both 0-1km & 0-6km layer shear are both strong (30 & 60 knots respectively), much like our frontal passage on this past Sunday, this will very likely be a highly over-sheared event. There continues to be mixed solutions across the hi-res guidance, with some rapidly strengthening convection to our south and robbing moisture and others keeping a more consolidated line. Regardless, there is consistent signaling in both environmental soundings and convection depiction in a limited severe threat that is further supported by limited synoptics and diurnal timing. Best timing is mainly 12z thru 18z with showers and isolated thunderstorms, with between 0.3-1.0" of rainfall expected along with some gusty winds over 30 mph. By Wednesday afternoon, winds will shift out of the west- northwest with strong cold and dry advection behind the front. Low temps will fall into the 30`s for much of the area. Drier and cooler for Thursday as high pressure fills in. Winds will turn from for the northwest to northeast and dew points will fall into the 20`s with high temps staying capped out in the 50`s. Low temps Thursday night will be the coldest of the week, falling into the low 30`s and upper 20`s. && .LONG TERM /FRIDAY THROUGH TUESDAY/... Strong 1030+ mb surface high will exit off the east coast on Friday, and there is excellent consensus in another calm, cool, and dry day Friday. GEFS members bottom out PWAT`s around 0.2" before moisture begins late Friday. With the high exiting off the coast and weak southerly flow returning, NAEFS shows PWAT`s steadily increasing throughout the weekend along with GEFS members stalling a weak front across the area by Saturday. So precip chances increase late Saturday and into Sunday. A warming signal is still very evident in the long term into next week with NAEFS pushing PWATS`s, heights, and temps all above the 90th percentile. So confidence is fairly high in a return to above average temperatures by next week. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... VFR for the time being, but expectation is that restrictions will quickly develop later tonight and into Wednesday as a strong front approaches the region. Southeasterly flow has developed across the forecast area today and is leading to a slow but gradual increase in moisture across the area. With dry air and high pressure still in place across the region, I do expect VFR to last for the next few hours. Clouds should quickly increase through 03z-05z and remain VFR as this occurs, with a possible exception at OGB. Low-level flow is southeasterly, and that usually favors stratus especially when skies are clear. This looks most likely to be maintained at OGB for several more hours with stratocumulus and cirrus being a bit further west. HRRR and LAMP guidance has recently suggested that a brief period of LIFR cigs are possible at OGB between 05z and 07z, but I am hesitant to include that in the TAF at this time. From there, the forecast is fairly simple, with moisture and rain increasing in coverage from west to east quickly after 08z. Rain should generally bring cigs/vis to MVFR (this is common in obs to our west) and I expect that to be the case given we`re already in the warm sector of this system. However, there should be embedded convection within this rain, so expect IFR cig/vis to occur at times, and I cover that in a TEMPO group at all sites. I don`t think there will be widespread thunder & don`t include it in the TAF, but don`t be surprised if there is some lightning with this. The heaviest rain generally looks to occur from 09z to 17z across the region, quickly pushing out of the area thereafter as dry air pushes in. Look for LLWS to occur during this time as well. I do think that some MVFR cigs will likely hang on for a couple hours after the rain stops, but generally should be out of here after 21z. Winds will start near the east or southeast this evening, quickly shifting out of the south and southwest ahead of the front. EXTENDED AVIATION OUTLOOK...No restrictions expected late in the week as dry air returns. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Charleston SC
1007 PM EST Tue Nov 29 2022 .SYNOPSIS... High pressure will prevail through late tonight. A cold front will move offshore Wednesday, followed by high pressure. Another cold front could briefly stall over the area this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... Cirrus clouds are expected to increase across the forecast area this evening, sourced from upstream convection. Return flow is expected to remain steady through the overnight hours. The forecast will feature steady temperatures through the rest of the evening, then gradual warming through daybreak. By sunrise, temperatures may warm by 2-4 degrees above mid-evening values. The mid-levels will consist of a strong trough over the north- central Plains in the evening. It`ll take on a slightly negative tilt as it moves over the Upper-Mid MS Valley overnight. Additionally, the jet stream will be in the vicinity of this feature. At the surface, low pressure over WI in the evening will shift NNE into Canada overnight, dragging with it a strong cold front. The front is expected to cross over the Appalachians late at night, with hints of a warm front developing to our north. Moisture will increase ahead of the front, with PWATs exceeding 1.25" late. The combination of the moisture, lift from the front, and lift in the mid/upper levels will generate a line of showers along/ahead of the front. Clouds will gradually increase this evening and overnight. The models have come into better agreement with the start timing of the showers. If anything, the trend has been ever so slightly slower with the arrival. So we have rainfree conditions most of the night, with slight chance to chance POPs very late far inland, where the stronger forcing and deeper moisture will be. Temperatures will fall into the 50s overnight, but should level off or start rising again late as the surface winds become more SE to S and clouds increase. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Wednesday: A strong shortwave embedded in the polar jet will dig across the Ohio Valley as a 514dam upper low propagates across southern Ontario. This shortwave will help drive a cold front across the Southeast U.S. as high pressure slides farther offshore of the Eastern Seaboard. Low-level moisture return ahead of the cold front will be slow to occur with most of the guidance only showing a ribbon of PWATs >1" and an axis of deep, vertically consistent moisture being confined to along and just ahead of the wind shift. The strongest Q-G forcing is forecast to remain displaced well to north within the region of modest DCVA ahead of the shortwave as it shears out of the Ohio Valley, but model cross sections show a narrow, but strong corridor of deep-layered UVVs passing through just ahead of the front, likely owing to low-level forcing with the front itself and some contribution from the tail end of the right entrance region of a subtropical jet streak. This will support a fairly large frontal rain band, which will likely be in a weakening phase as it approaches the coast due to some thinning of the ribbon of deep-layered moisture and increasing mixed-layer stability. All ensemble members are showing some degree of measurable rainfall during the morning into the afternoon even as the band weakens as it approaches the coast. Pop were raised to 70-90% with QPF amounts ~0.10-0.50 inches as a result. Rain chances will quickly end by early evening as the front pushes offshore and a drier post-frontal airmass settles in. Although shear modest shear will be in place in the warm sector, very limited instability will negate the overall severe potential as the situation does not look favorable for a late fall high shear/low CAPE severe event. SPC removed the marginal risk from South Carolina and much of Southeast Georgia from the 29/17z Day 2 WFO guidance outlook. Highs will be closely tied to high quickly rain moves in from the west. Areas near the CSRA and southern Midlands may struggle to reach 70 before the onset of rain while areas to the east may have sufficient time to warm into the lower-mid 70s. A general blend was used to construct Wednesday`s highs. Lows Wednesday night will range from the upper 30s/lower 40s well inland to around 50 at the beaches. Thursday and Friday: Quiet and dry conditions will prevail during this time as high pressure extends across the region. Highs will warm into the upper 50s/lower 60s Thursday then recover to the mid- upper 60s for Friday. Lows Thursday night will drop into the mid- upper 30s well inland to the lower 50s at the beaches. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Mostly quiet conditions will dominate for much of the extended period as the region is forecast to remain along the northern periphery of a large mid-level subtropical anticyclone centered over the Gulf of Mexico. An isolated shower or two could occur near the coast by Friday as weak coastal trough tries to develop just offshore, but confidence is not high enough to justify a mentionable pop just yet. A cold front could briefly stall over parts of the Southeast U.S. this weekend before lifting back to the north as a warm front. Uncertainties in the degree of moisture return and where the front stalls support keeping mentionable pops out of the forecast for now. Above normal temperatures can be expected. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... Conditions across KCHS/KJZI/KSAV are expected to remain VFR through the overnight hours. A band of pre-frontal convection is expected to near the terminals during the first couple of hours of daylight Wednesday morning. Latest run of the HRRR and HREF indicate that the band of showers will push across the terminals between 14-18Z with gusty SW winds, highlighted with TEMPOs. In the wake of the showers, ceilings are expected to lower into MVFR across KCHS/KJZI with periods of IFR at KSAV, generally after 18Z. Extended Aviation Outlook: The risk for showers will end Wednesday afternoon. Otherwise, there are no concerns. && .MARINE... Tonight: High pressure will move off the coast of the Northeastern U.S. while a cold front approaches from our west. This will cause winds to veer to the SE this evening, then S by daybreak Wednesday. Additionally, winds will be sustained around 10 kt in the evening, increasing to around 15 kt late. Seas will respond by building to 2-3 ft. Wednesday through Sunday: The main concern for this period centers on Wednesday night into Thursday. There will be a risk for Small Craft Advisory conditions during this time as north to northeast winds initiate during a period of post-frontal cold air advection followed by a pinching of the pressure gradient with high pressure centered to the north. Winds could reach as high as 20-25 kt with gusts to 30 kt for all coastal legs with conditions in the Charleston Harbor reaching 15-20 kt. Seas will build to 4-6 ft nearshore waters and 5-7 ft over the Georgia offshore leg. Conditions in the Charleston Harbor could fall just short of advisory levels, but this will need to be watched. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM... LONG TERM... AVIATION...NED MARINE...
Area Forecast Discussion
National Weather Service Grand Rapids MI
945 PM EST Tue Nov 29 2022 LATEST UPDATE... Update .UPDATE... Issued at 945 PM EST Tue Nov 29 2022 Cold front is knocking on the door and there has been a few tstms across WI/IL within the line of showers preceding the front. Most of the storms are now restricted to nrn Lk MI, but really can`t rule out a rumble of thunder anywhere as that band of showers crosses the area over the next few hours. Wind gusts associated with the showers have only been around 30-35 kts, although some higher gusts have been noted back behind the cold front. The Wind Advisory is somewhat marginal since the narrow cold frontal rain band isn`t doing much and the highest winds are not expected until Wednesday afternoon, but will make no changes at this time. Temperatures have warmed into the mid to upper 50s this evening just ahead of the front, but will be near freezing by the morning commute. Current thinking is that travel for the morning commute should be okay since road temps are currently 45-50 and it will take some time to bring those down. Plus the lake effect snow showers do not get going in earnest until after 9 or 10 am. && .DISCUSSION...(This evening through next Tuesday) Issued at 323 PM EST Tue Nov 29 2022 - High Winds / Rain showers to Lake Effect Snow The surface low has developed as expected from the digging 160 knot jet core from British Columbia dug into the base of the upper trough over western CONUS. It is now being driven by a 130 knot jet core and will race northeast across wester Lake Superior later this evening, exiting into central Ontario Wednesday. This drives a strong cold front through here around midnight. 850 temperatures fall around 16c in 12 hours, which is significantly more than any cold front we have had in the past 3 months. The front that brought us all the snow only had a 12c drop in 12 hours, which was similar to the cold front that came through here on September 22nd. Another way to look at that is at 2 pm there was a 25 degree temperature drop from eastern to western Iowa. So, what this means for us, since gulf moisture is starting to stream into the system on the warm side of it, and area of showers and thunderstorms has already developed from Southern Illinois southward. The northern edge of that will quickly develop northward. We should see showers in our area by sunset or shortly after that. A narrow frontal rain band is forecast by the high res models just in front of the cold front over our area. This will be in the 11 pm (MKG) to 2 am (JXN) time frame. Winds may gust into the 40 to 50 mph range as this convective band moves through our area. The instability is marginal at best for thunderstorms here, but it is not out of the question. Actually through the gusty winds will happen with the convective line whether there is or is not thunder. Due to the strong pressure gradient that will increase this evening, surface wind will be gusty. We issued a wind advisory from 10 pm until 8 pm Wednesday. The 10 pm to 2 am time range was to cover wind gusts with the convective line on the cold front. Once the cold front comes the showers will come to an end. Winds will shift to the west northwest while temperatures fall from the lower to mid 50s at midnight to the mid 30s by 3 am. As the core of the coldest air moves in, wind gusts will increase into the 40 to 45 mph range by late morning or early afternoon. The highest wind gusts are expected between 2 pm and 6 pm Wednesday. As for snow with this system, the trusty rule of being on the cyclonic side of the polar jet will work great in this event. Just about all of the high resolution models go in that direction but the HRRR seems to this time have a better handle on the snow showers activity than does the NAMNEST. The HRRR shows inversion heights reaching near 8000 ft while the NAM only shows around 5000 ft. Given how deep and wrapped up this system is and how much cold air trails it, I am going with the HRRR snow forecast. This gives us narrow band of strong snow showers that extend west to east across most of southern Lower Michigan from mid morning till early evening. Most locations should see only a dusting to an inch but some location just east of US-131, north of Kalamazoo through Reed City could see over 2 inches. With winds of 20 to 30 mph gusting 40 to 50 mph and temperatures during the day light hour mostly in the upper 20s to lower 30s, this will cause some local travel issues. There may be morning and more so, evening drive time travel issued due the combination of the gusty winds, snow and blowing snow. - Quiet Weather Returns by Thursday The back edge of upper cold pool moves east of our area by early Thursday morning. That will end the snow showers and calm the winds down too. Shortwave ridging between the system departing the area and the next upstream Pacific system will provide dry weather for most of Thursday and all of Friday. It will warm up again too, highs should be well up int the 40s by Friday once again. - Two more system to impact our weather The system over the weekend has a lot of variance in the models, both model to model and run to run with the same model. One way or the other this too will have a decent amount of wind with it as there is a 135 knot jet core associated with it. This will mean rain showers to snow showers Saturday into Sunday. At this time the system is moisture starved. Do not expect much precipitation with this storm. -Then the cold air really comes back The next system ,that comes through in the Tuesday to Wednesday time frame, has had some continuity issues in the models. Even so, most of the ensemble members of the GFS and Ecmwf keep the cold air in place once it gets hear. That is because a large blocking upper high develops near Greenland. This is a classic upper high location if one wants cold weather in Michigan. It`s expect rain showers to snow showers with this system too. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 710 PM EST Tue Nov 29 2022 Winds are the main aviation impact over the next 24 hours. This evening we have southeast winds gusting up to 30 knots which switch to the southwest overnight then west by daybreak Wednesday, increasing through the day. The winds on Wednesday will gust as high as 40 kts at times in the afternoon, but there may also be a brief period of 40 kt gusts with the band of showers which comes in from the west later this evening. This narrow cold frontal rain band could even have a tstm or two embedded in it. As far as the ceilings and vsbys, the current VFR conditions will trend into the MVFR category by 03Z or so, then some brief IFR cigs/vsbys will be possible for about an hour as that band of rain showers and isolated storms moves through. Conditions predominately MVFR on Wednesday as snow showers develop, although occasional IFR/LIFR vsbys are possible under any heavier snow showers which develop. && .MARINE... Issued at 219 PM EST Tue Nov 29 2022 Our gale warning now runs from 7 pm until 4 am on Thursday. The strongest winds will be after the cold front comes through midnight once the cold air comes in to mix the stronger winds down. The winds are expected to remain strong into early evening Wednesday. The peak winds are expected to be during the mid to late afternoon. Winds will quickly diminish between mid morning Thursday into mid afternoon. Then our next system will repeat the cycle of south winds increasing to near gale force Friday, then the cold air comes in Saturday so strong winds will continue into later Saturday. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Wind Advisory until 8 PM EST Wednesday for MIZ037>040-043>046- 050>052-056>059-064>067-071>074. LM...Gale Warning until 4 AM EST Thursday for LMZ844>849. && $$ UPDATE...Meade DISCUSSION...WDM AVIATION...Meade MARINE...WDM
Area Forecast Discussion
National Weather Service Lincoln IL
713 PM CST Tue Nov 29 2022 .SYNOPSIS... Issued at 321 PM CST Tue Nov 29 2022 Gusty southerly winds will continue into this evening ahead of a cold front that will quickly move through central and southeast Illinois. Showers and a few storms are expected to develop along the front this evening, while isolated severe wind gusts may be associated with the showers and storms, primarily east of I-55. Much colder temperatures, gusty west winds, and dry conditions are expected for Wednesday. Precipitation chances return from Sunday into early next week. && .UPDATE... Issued at 710 PM CST Tue Nov 29 2022 As of 7 pm this evening, a cold front is moving east across I-55 and is expected to exit central Illinois into Indiana between 10pm and midnight tonight. Scattered showers and isolated storms have been in place along and ahead of the front but should quickly end once winds turn northwesterly. While winds have mostly come up just shy of reaching advisory criteria (gusts of 45 mph), several sites have been very close ahead of the front, and earlier obs from DVN and MLI did show gusts in excess of 45 mph immediately behind the front right as winds veered to westerly. Will let the wind advisory ride for the remainder of central/east central Illinois this evening. In terms of the severe threat, some of the shower have exhibited weak, transient rotation. 00Z ILX sounding did not indicate any notable instability, but surface dew points have been creeping up across east central Illinois, especially near and south of I-70, and RAP continues to indicate the potential for a little over 100 J/kg MLCAPE just ahead of the front. Will have to continue to monitor closely but the weak instability and storms struggling to maintain stronger updrafts should keep the severe threat it check. Finally, temperatures fall quickly behind the front, dipping near or below freezing within about 2 to 3 hours of frontal passage. Any lingering wet spots on roads could freeze and result in slippery conditions, particularly on elevated surfaces such as bridges and overpasses. && .SHORT TERM...(This evening through Wednesday) ISSUED AT 321 PM CST Tue Nov 29 2022 Light showers did develop in southeast IL this afternoon but have quickly moved off into IN. The forecasted cold front is on the doorstep of IL and will quickly move through the CWA this evening, reaching GBG by 5 pm, I-55 by 7 pm, I-57 by 9 pm, and then out of the state between 10 and 11 pm. Intense showers are expected to develop along the front in the next hour or 2 and then quickly move northeast while the front move to the east. Gradient winds ahead of the front will remain gusty with gusts of 40-45 mph possible at times. Strong dynamics along the front and strong low level winds could allow some storms, especially east of I-55, to produce some isolated damaging wind gusts this evening. Winds behind the front will be gusty as well, still possibly reaching up to 40 to 45 mph. Hence, the wind advisory will continue. Most of the area will be dry by midnight, but some light precip is possible in the far southeast just after midnight. As evident on the sfc maps and seeing the tight temp gradient, temps will plummet behind the front. This could lead to some possible icy spots and residual moisture from the showers will likely quickly freeze in spots before the wind evaporates it. Temps will quickly drop this evening and through the night. Temps overnight will be below 30 degrees. Gusty winds tonight will bring about single digit to low teen wind chills overnight. Wed high temps will likely only climb about 10 degrees to the lower 30s to near 40. Skies will be mostly sunny tomorrow, however, northwest winds will be gusty again and daytime wind chills will remain in the teens. .LONG TERM...(Wednesday night through Tuesday) ISSUED AT 321 PM CST Tue Nov 29 2022 Dry conditions are expected the rest of the week and into most of the weekend. The next weather system will arrive Sunday with chances of precipitation, which will continue into the beginning of next week. Far enough out and plenty of differences in the models, so p-type will just be rain, snow or a mix of rain and snow. Temps through the extended will be a roller coaster, with cold temps for one day and then warming back to around normal for 1-2 days, then cooler again over the weekend, then warming again at the start of next week...enjoy. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 527 PM CST Tue Nov 29 2022 A strong cold front is sweeping across central Illinois this evening. Variable MVFR/VFR conditions and strong southerly winds gusting to around 30 kt will continue ahead of the front, then will veer to the NW behind the front with MVFR ceilings becoming more prevalent. A brief line of showers is expected with the front, and an isolated storm cannot be ruled out. && .ILX WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 9 PM CST this evening for ILZ031-037-038- 041>043-048-051>053. Wind Advisory until midnight CST tonight for ILZ044>046-054>057- 061>063-066>068-071>073. && $$ UPDATE...Deubelbeiss SYNOPSIS...Auten SHORT TERM...Auten LONG TERM...Auten AVIATION...Deubelbeiss
Forecast Discussion: Over the long term, battle continues between
Gulf ridge and cold intrusions out of Canada. Upper trough moves
across the northern U.S. Friday through Sunday. Next trough drops a bit deeper into the Plains and Great Lakes early next week. High pressure settles over the area Thursday with below normal nighttime temperatures expected Wednesday night and Thursday night. The first trough spins up a strong surface low over the Plains Friday and drives it northeast into the Canadian maritimes through the weekend. That will push a weak cold front through here Saturday morning. Gusty winds and some rain is likely with the front Friday night and Saturday. Southwest flow will drive moist air and above into the area Monday. This will set the stage for what could be a couple day rainfall event as a warm front sets up nearby starting Sunday and continuing into the early next week. Another cold front moves through the area later Tuesday with colder air/below normal temperatures behind it. && .Aviation...(00Z TAF Issuance) Issued at 639 PM EST Tue Nov 29 2022 IMPACTS: -Gusty winds through tonight, including LLWS roughly WS020/19050KT -Widespread showers and storms this evening into the overnight -MVFR ceilings/visibility at times; possible IFR in strongest storms DISCUSSION: Low pressure system still on track to impact area terminals with gusty southerly winds, thunderstorms, and MVFR ceilings and visibility this evening into the overnight hours. IFR conditions are also possible in the strongest of storms. Low level wind shear will also be an impact around 2K feet from the south around 40-50kts, ending by 6z. By daybreak, VFR conditions should return as the front passes by late Wednesday morning with skies clearing and WNW winds through Wednesday evening. CONFIDENCE: Medium on all elements. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Mesoscale...RAS Short Term...CG Long Term...KJF Aviation...MK
Area Forecast Discussion
National Weather Service Midland/Odessa TX
520 PM CST Tue Nov 29 2022 ...New AVIATION... .SHORT TERM... (This afternoon through Wednesday night) Issued at 204 PM CST Tue Nov 29 2022 500mb RAP initialization shows the upper trough centered across Colorado this afternoon. Its associated jet max passing overhead is contributing to a very windy day across the region. The strongest winds remain out west across the Guadalupe and Davis Mountains where a High Wind Warning remains in effect through late this evening. Strong winds have found their way into the Permian Basin as well, prompting an expansion of the Wind Advisory through north-central Lea County and the northwestern Permian Basin. As the jet max departs and diurnal mixing subsides after sunset, winds will come back down to more modest levels. After a mild day with high temperatures reaching the mid 70s for most thanks to downsloping westerly winds, high pressure building southeastward through the central Plains will push a cold front through overnight. Temperatures will tumble back below freezing north of I-20 with lows in the 30s and 40s to the south. High temperatures tomorrow will be 10-15 degrees below average behind the front with east-northeasterly winds, topping out in the 40s north of I-20 and the 50s and 60s to the south. Northerly flow behind the front will be short lived as the high pressure center moves into the Mississippi Valley and southeasterly winds return Wednesday night. Lows will be a little bit warmer as a result, with freezing temperatures limited to the far northern zones and the higher elevations. -Munyan && .LONG TERM... (Thursday through Monday) Issued at 204 PM CST Tue Nov 29 2022 Zonal flow is expected across the United States through at least early next week. This westerly flow will favor warm, downsloping winds keeping temperatures near to above normal. A series of upper level troughs will develop and move east within the flow but will remain well north of our CWA. Normally this means little chance for rainfall, however the arrival of a cold front on Saturday will coincide with Pacific moisture and a strengthening jet stream to give a chance of rain from southeastern New Mexico to the Permian Basin. Rain chances will continue into Saturday night before drier air arrives Sunday. && .AVIATION... (00Z TAFS) Issued at 502 PM CST Tue Nov 29 2022 Winds across the plains are starting to decrease and by 01Z should be below 12kts at all TAF sites. Cold front still n of LBB as is generally expected to be HOB/MAF 04Z-05Z, INK about 06Z. By 12Z winds will light, then e-se Wed. Low-level water imagery shows wave action across/downstream of mtns as such light low flying aircraft can expect severe turbulence INVOF mtns into the evening. && .PRELIMINARY POINT TEMPS/POPS... Big Spring 73 31 50 36 / 0 0 0 0 Carlsbad 70 32 49 32 / 0 0 0 0 Dryden 81 39 56 39 / 0 0 0 0 Fort Stockton 76 35 56 38 / 0 0 0 0 Guadalupe Pass 62 34 47 34 / 0 0 0 0 Hobbs 66 27 48 32 / 0 0 0 0 Marfa 69 31 60 30 / 0 0 0 0 Midland Intl Airport 73 31 51 37 / 0 0 0 0 Odessa 72 32 51 37 / 0 0 0 0 Wink 73 31 52 36 / 0 0 0 0 && .MAF WATCHES/WARNINGS/ADVISORIES... TX...High Wind Warning until 10 PM CST /9 PM MST/ this evening for Guadalupe Mountains Above 7000 Feet-Guadalupe and Delaware Mountains. Wind Advisory until 7 PM CST this evening for Davis Mountains Foothills-Eastern Culberson County. High Wind Warning until 7 PM CST this evening for Davis Mountains. NM...High Wind Warning until 9 PM MST this evening for Guadalupe Mountains of Eddy County. Wind Advisory until 6 PM MST this evening for Eddy County Plains. && $$
Area Forecast Discussion
National Weather Service Morristown TN
935 PM EST Tue Nov 29 2022 ...New UPDATE... .UPDATE... Issued at 922 PM EST Tue Nov 29 2022 Current forecast still looks reasonable. Portions of the southern half of the area are approaching or have already exceeded an inch of rain. Hi res models generally indicate a break in the steadier rain soon, and radar is trending that way at the moment. With some additional moderate to heavy rainfall expected, will need to continue to monitor for localized flooding issues. So far have not seen any observations higher than 42 mph in the mountains, but highest winds expected a bit later. Will leave the wind warning as is for now. No significant changes planned with this update. && .SHORT TERM... (This evening through Wednesday) Issued at 306 PM EST Tue Nov 29 2022 Key Messages: 1. Showers and thunderstorms tonight, especially south of Interstate 40 with storm total rainfall around 2". Isolated flooding possible in locations with multiple rounds of heavy rainfall. 2. High wind warning for gusty winds in the foothills and high winds in the east Tennessee mountains late tonight through the overnight. Discussion: A large upper trough is currently situated in the central CONUS, with GOES visible satellite showing anvil blowoff from ongoing elevated convection west of us beginning to reach near our Plateau counties. SPC HREF guidance brings these storms and showers to the Plateau counties by 00z. Rain and thunderstorms will then continue for most of the night, with the cold front arriving tomorrow morning to clear the rainy weather out. GFS has an interesting double jet structure in association with the upper trough, with a polar jet rounding out the trough, and a subtropical jet coming out of Texas. SPC currently has a slight risk just west of our most southwest portion of the with the plateau counties and anyone west of Knoxville in a marginal risk for severe wind. The main headlines from a severe weather perspective all remain to our west in Alabama and Mississippi. Meanwhile over here CAM guidance maintains a potent low level inversion for most of the night concurrent with the best dynamics aloft, so while we cannot rule out severe weather, it`s not expected. Definitely expecting thunderstorms though, which will give us some periods of heavy rainfall, especially the southernmost border counties along Georgia. Cannot rule out isolated flooding in our southernmost counties, with guidance showing a couple rounds of heavy storms moving through Alabama and Georgia through southern Tennessee. Late tonight as the surface trough quickly moves northeast to our northwest, the 850 mb jet strengthens across the area. 850mb flow from the south to southeast across the Smokies will develop overnight. This, combined with a tight pressure gradient along the mountain range will produce gusty downsloping winds along the east Tennessee mountains into the foothills. NAM and HRRR cross sections back the general idea up, with strong omega values indicative of downward vertical motions along the Smokies. The current NPW looks to be in good shape with no updates planned. By Wednesday morning the rain and storms will be on their way out, in advance of the incoming cold front. Front will sweep across the area in the morning hours, taking our mild temperatures out with it. Post frontal winds could be a bit breezy, so altogether a not so pleasant day. Afternoon temperatures tomorrow will be much cooler && .LONG TERM... (Wednesday night through next Tuesday) Issued at 306 PM EST Tue Nov 29 2022 Key Messages: 1. Below normal temperatures Thursday then gradually warming through the remainder of the extended period. 2. Chance of rain showers returns this weekend and into early next week. Discussion: Longwave troughing across the Eastern CONUS will gradually lift to the northeast on Thursday with upper ridging beginning to build in. At the surface, we continue to have a very cold, dry airmass with high pressure centered over the region. This will keep temperatures below normal on Thursday with a sunny, clear sky. By Thursday night and Friday, surface high pressure will shift to the east with return southwesterly boundary layer flow allowing for a gradual increase in temperatures and an increase in clouds due to weak isentropic lift. A strong shortwave trough is forecast to move eastward across the Great Lakes on Saturday with an associated surface low. There will be a trailing cold front to the southwest across the Ohio Valley and Mississippi Valley. As this front moves east on Saturday, scattered rain showers are expected across the region. With limited moisture return, QPF is forecast to remain low, generally a one-quarter inch or less. We expect to have a brief dry period on Sunday as the front becomes stationary just to our south across MS/AL/GA. Sunday night into Monday, this front is forecast to move back northward as southwesterly 850mb flow increases ahead of shortwave troughing across the Great Plains. An area of rain showers is expected along and north of this front as it lifts northward on Monday with strongest boundary layer convergence and PoPs to our west. && .AVIATION... (00Z TAFS) Issued at 607 PM EST Tue Nov 29 2022 Will see showers and some thunder around at times overnight, with thunder most likely at CHA. Cigs/vsby will drop to MVFR at times in heavier precipitation, and will likely become predominantly MVFR later tonight. There may be at least brief IFR conditions, but timing uncertainty as well as lower probability means it will be left out for now except for a tempo at CHA. The low level jet will be strong for a period tonight, and if surface winds are lighter than expected LLWS may occur. Conditions will quickly trend VFR as precip ends and clouds scatter out Wednesday morning. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 50 62 31 50 / 100 30 0 0 Knoxville McGhee Tyson Airport, TN 50 61 28 49 / 100 40 0 0 Oak Ridge, TN 47 61 28 48 / 100 40 0 0 Tri Cities Airport, TN 49 59 25 46 / 100 60 0 0 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...High Wind Warning until 10 AM EST Wednesday for Blount Smoky Mountains-Cocke Smoky Mountains-Johnson-Sevier Smoky Mountains-Southeast Carter-Southeast Greene-Southeast Monroe-Unicoi. VA...NONE. && $$ SHORT TERM...Wellington LONG TERM....JB AVIATION...