Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/12/22

Area Forecast Discussion
National Weather Service Birmingham AL
725 PM CST Fri Feb 11 2022 .UPDATE... Evening Update and 00Z Aviation. && .SHORT TERM... /Updated at 0634 PM CST Fri Feb 11 2022/ A double frontal structure was just northwest of Central Alabama this evening. The latest surface map has 40s and 50s dew points just south of the area. As we head into the overnight hours, we will have increasing near ground level moisture over a cool ground. This will promote the development of some fog and low clouds after midnight. The specific placement is still being worked on, but mostly likely will spread northward south of I-20. Some of the fog may become dense in places. Will monitor another hour or so and may add some mention into the HWO overnight. The clouds and fog will be relatively short lived as the cold front moves into the north half of the area Saturday. Some mixing will also take place after sunrise. 75 Previous short-term discussion: /Updated at 1142 AM CST Fri Feb 11 2022/ Through Saturday. Features of Interest. A longwave trough extended from over Southern Canada southwest to over South Texas. Surface high pressure was centered off the Southeast Atlantic Coast while a sharp cold front extended from surface low pressure over the Great Lakes and extended southwest into Northern Texas. Today. A shortwave trough will move over the area in dry fashion this afternoon, ahead of the longwave trough diving southeast over the Central Plains. The pressure gradient between an approaching cold front from the northwest and surface high pressure to the southeast will result in breezy conditions from the southwest at times this afternoon. Expect fair skies today with highs ranging from the upper 60s in the higher elevations east to readings in the lower 70s south and west. Winds will be breezy at times from the southwest at 7-14 mph. Tonight. The upper longwave trough will dive southeast into the Southern Plains and Mid-South Regions overnight. The associated cold front will push southeast into the northwest portion of the state later tonight. Expect some more clouds northwest overnight, but increasing southerly flow in the lower levels will allow low-level moisture in gradually increase with time. Patchy fog is forecast to develop through the early morning hours and persist through mid morning across the southern third of the forecast area and across the east-central portions of the area. Lows will range from the upper 40s northeast to the lower 40s elsewhere. Winds will be from the south 3-6 mph. Saturday. The longwave trough will move into the region during the day Saturday as the cold front pushes through the forecast area. Expansive surface high pressure extending from Southern Canada down into Texas will build into the region from the northwest through the day. Clouds will continue to increase through the morning hours with isolated showers generally along and northwest of the Interstate 59 corridor. Highs will range from the upper 40s northwest to the lower 70s southeast. Winds will shift from the south to the northwest 6-12 mph through the day. 05 .LONG TERM... /Updated at 0223 PM CST Fri Feb 11 2022/ Model trends continue to show weaker forcing and less moisture as the mid level trough moves through the area. The chance of light rain or snow showers quickly diminishes Saturday evening, and will not carry measurable pops or weather beyond 00Z. Won`t rule out a sprinkle or flurry, but chances are very low. A cold airmass will settle over the area to begin the week, but quickly moderates ahead of the next frontal system, impacting the area Thursday. Too early for any more details than what is mentioned in the previous discussion, and will continue to highlight the possibility of tornadoes in the HWO. 14 Previous long-term discussion: /Updated at 0337 AM CST Fri Feb 11 2022/ Saturday night through Thursday. Western ridge/eastern trough pattern remains in place for the weekend. A shortwave moves through the area Saturday night, eventually phasing with the subtropical jet once it passes the area, while an associated strong cold front moves through. Models seem to be coming into agreement on the shortwave remaining positively tilted with weaker 850-700mb frontogenesis. Did consider removing PoPs altogether Saturday night, but with some high res guidance including the HRRR and HiResW-FV3 still indicating light precipitation as well as some GEFS members, and given decent 850-700mb mean RH values, will maintain the slight chance of rain/snow for the area and continue to monitor. A clipper system then moves in on Sunday. At this time it remains moisture starved, but it will bring a secondary cold front keeping temperatures below normal Sunday and Sunday night. Winds begin to shift to the west on Monday with temperatures still running a little below normal. A pattern flip occurs next week as the West Coast ridge is replaced by a trough, and a ridge strengthens over the western Caribbean up into the Bahamas. Have continued to incorporate the warmer NBM percentiles for highs beginning on Tuesday. The synoptic pattern for Thursday checks a lot of boxes for severe weather across the Deep South and Mid-South with a low amplitude southern stream trough and deepening surface low lifting northeastward across the Ozarks, with an associated mid-level speed max on the shortwave`s southeast flank. A strong 60 to 70 kt LLJ will also bring 65F dew points northward. I suspect models are underdoing the forecast CAPE values in this setup. This system is several days out and there is some uncertainty regarding how the southern stream trough interacts with the northern stream along with an upstream wave, but will introduce a low confidence tornado mention into the HWO. 32/Davis && .AVIATION... 00Z TAF Discussion. A cold front moves into the area Saturday. Light and variable winds are anticipated overnight and become northwest by afternoon around 10kts. A few gusts are also possible. The restrictions come in the form of fog and low clouds possible early Saturday. Warm advection of very near surface moisture will take place after 06z. How widespread and what terminals are affect remain the questions at hand. Will start off will tempo IFR vis/ceilings at MGM and vis at TOI. It appears the next in line would be TCL/EET. This will be relatively short-lived and gone by 15z. 75 && .FIRE WEATHER... Dry weather will persist through the weekend, with only a low chance of a shower in the extreme northwest Saturday afternoon. Moisture does increase ahead of a cold front, with minimum RH values in the 35 to 50 percent range tomorrow afternoon. Ceiling heights should remain above 2kft. Low RH values (20-30%) return Sunday through Tuesday. Southwesterly 20ft winds become northerly Saturday morning, increasing to 6-10mph through the day and remain elevated Sunday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 38 58 24 46 21 / 0 0 10 0 0 Anniston 40 62 28 46 24 / 0 0 10 0 0 Birmingham 43 59 28 46 25 / 0 10 10 0 0 Tuscaloosa 41 61 28 49 26 / 0 10 10 0 0 Calera 41 62 30 48 28 / 0 0 10 0 0 Auburn 41 67 34 49 28 / 0 0 10 10 0 Montgomery 41 67 34 53 28 / 0 0 10 0 0 Troy 42 73 35 52 29 / 0 0 10 10 0 && .BMX WATCHES/WARNINGS/ADVISORIES/... None. && $$
Area Forecast Discussion
National Weather Service Cleveland OH
926 PM EST Fri Feb 11 2022 .SYNOPSIS... Low pressure will move across eastern Ontario tonight dragging a strong cold front through the region. High pressure will attempt to build into the Ohio Valley late Saturday, but a series of troughs will drop across the region through the weekend. High pressure will more firmly move in early next week before moving east and allowing a warm front to lift through by Wednesday. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Rain showers are beginning to exit east of the area this evening as colder air begins to filter in behind the first cold front. A secondary, reinforcing cold front will arrive later tonight into tomorrow morning, introducing the next chance for snow showers, especially across NE OH and NW PA. Previous Discussion... Latest surface and RAP analysis has the cold front still over western Ohio, but it appears to be east of TOL and moving into FDY. This front is tied to a significant mid/upper shortwave trough digging into the Upper Midwest and western Great Lakes with an associated 996 mb surface low passing north of Lake Huron. Strong upper divergence from the right entrance of a 100-110 knot H3 jet progressing out of lower Michigan is leading to a 45 to 50 knot southwesterly low-level jet. Some mixing of this LLJ combined with a tightening surface pressure gradient and downsloping near the lakeshore is leading to SSW winds gusting to 30-40 knots at a few sites, namely Burke Lakefront Airport and Fairport Harbor Lighthouse. Inland areas are seeing gusts mainly in the 25-30 knot range, so did not issue an advisory given the fairly isolated coverage of the higher gusts. Widespread showers associated with the aforementioned upper divergence and strengthening frontogenetic forcing have now spreading across the entire area, so expect a wet evening commute. The deep surface low will lift through eastern Ontario early tonight dragging the cold front across the rest of the CWA this evening. The steadiest rain will be confined to the Ohio/PA line by 02Z exiting the rest of the area by 04Z. This front is more of a wind shift and moisture gradient since upstream observations are not showing a rapid drop in temps behind it. There will be enough post frontal cold advection to change lingering light precip to light snow showers before tapering off. Winds behind the front this evening will quickly diminish to 10-20 knots while veering WSW except for 20-25 knots lingering near the lakeshore the first half of the night. A punch of drier mid-level air behind the front should lead to a period of mainly dry conditions in the 04 to 08Z timeframe before snow showers increase ahead of a secondary cold front/surface trough. This trough will bring in the true arctic air. NAM and RAP BUFKIT soundings immediately ahead of the trough suggest a notable increase in low and mid-level moisture in the 08-12Z timeframe with 850 mb temps falling to -13 to -15C by 12Z and inversion levels rising to 7-8 thousand feet. This will set up a lake response as lake induced CAPE builds to a conditional couple hundred joules with winds veering to westerly and a period of lift in the DGZ coincident with the trough passage. Blended in higher PoPs from about 08Z through mid morning, especially from Lorain County east through the primary snowbelt of NE Ohio and NW PA. HREF members suggest that the aforementioned parameters plus south shore convergence as the trough passes will push a burst of snow through these areas putting down a quick few tenths to inch and a half. The accumulating snow will however not last long because moisture depth and inversion levels are expected to quickly tank Saturday afternoon with a loss of Omega, as well as increasing boundary layer shear as weak shortwave ridging attempts to build in ahead of the next mid/upper shortwave trough. This will lead to a rapid decrease in coverage and organization of any snow bands Saturday afternoon, but still kept PoPs fairly high for scattered light snow showers and flurries in both the primary and secondary snowbelts through evening given 850 mb temps continuing to cool to -15 to -20 C and continued WNW flow off the lake. Lots of water has opened up the past several days, so believe forecast soundings are probably underestimating the amount of latent heat flux despite the lowering inversion. Clouds will remain widespread Saturday night as the next shortwave drops into the western Great Lakes. Increasing mid- level moisture and upper forcing will spread light snow across Lake Erie into the northern tier of counties, so brought back PoPs after 10Z. Lows tonight will fall into the low/mid 20s with not much rise on Saturday given strong cold air advection. Saturday night will be very cold with lows dipping into the single digits and low teens. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... A clipper will move across the region Sunday into Sunday evening. Moisture and lift are limited enough that a broad synoptic shield of snow is unlikely. However, models remain in agreement in showing PVA ahead of a potent vort max that will move west to east across the region Sunday afternoon and evening to go along with an increase in low to mid-level moisture. Guidance shows a subtle low to mid-level trough axis crossing the region during the afternoon and evening as well. Forecast soundings show steep low-level lapse rates developing across the entire region during the day Sunday, including through a dendritic growth zone (DGZ) that will be located 2-4k feet above the ground thanks to the cold airmass in place. Given what looks like sufficient saturation in and above the DGZ to go along with the various sources for lift, feel that much of the area will at least see some flurries and scattered snow showers Sunday afternoon and evening. Continued to carry slight chance to chance POPs area-wide for this...suspect POPs will need to go up as we get closer and that much of the area, even outside of the snowbelt, can see a dusting of snow Sunday afternoon or evening. With steep low-level lapse rates through the DGZ, some snow showers could have a bit of intensity. With highs struggling to near 20 on Sunday and temperatures dropping into the single digits for most areas Sunday night, even a light amount of snow could stick to roads and cause slick conditions, with a higher traffic volume than a normal Sunday evening expected given a certain nationally televised sporting event that will be taking place. Believe that today`s runs of the regional Canadian model (RGEM) and European are doing the best job of showing the rough mesoscale set- up Sunday into Sunday night, which becomes important when trying to pin-down lake effect potential not only off of Lake Erie but also off of Lake Michigan towards the Toledo area. Am expecting a broad west to west-northwest flow across the region Sunday into Sunday evening, turning more northwesterly later Sunday evening, and then backing more westerly late Sunday night into Monday morning. The RGEM and Euro are both keying on a surface trough, connected to Lake Michigan, working across extreme southern MI or far northwestern OH towards western Lake Erie Sunday into Sunday evening. We often see a trough develop here with that kind of flow. Believe the NAM`s idea of taking this trough towards west-central OH is wrong due to what appears to be a significant error in handling the heat/moisture flux off of Lake Erie. Forecast soundings for Sunday afternoon and evening in Toledo show a fairly deep layer of saturation and steep lapse rates in the low-levels, and believe this trough may help focus activity off of Lake Michigan into far northwestern OH on Sunday. So, have some light snow accumulations in the grids here, and some bursts of moderate to briefly heavy snow wouldn`t be shocking. It`s possible this trough sets-up just north of the OH / MI line on Sunday, but even if that`s the case it should sink south into Sunday evening as the winds gain more of a northwesterly component. The Euro and RGEM show this same trough connecting to the southern shore of Lake Erie Sunday afternoon through early Monday, and both models have 0.10-0.20" of QPF in the Cleveland area as a response. Given a decent chunk of open water both east of the islands and along the central lakeshore, which will encourage modification of the air over that part of the lake and upward motion, believe it makes sense for this trough and convergence to focus in this area. With the synoptic lift described above from the clipper system moving through late Sunday into Sunday night, expect a fair amount of lake enhancement to develop, focusing on where this surface trough / convergence sets-up. With 850mb temperatures of -18 to -20C and 700mb temperatures approaching -30C Sunday evening, there will be moderate to nearly extreme instability over any open water with inversion heights rising to 8-10k feet. These numbers further argue for a robust lake response. As winds turn more northwesterly later Sunday evening expect the trough to push inland, causing the lake effect to move onshore and lose organization. Farther east, probably enough moisture flux off the icy waters for at least some lake enhancement into the rest of the primary northeast OH / northwest PA snowbelt as the synoptic support maximizes Sunday evening. As winds turn more westerly into Monday morning there may be another uptick in snow showers along the eastern lakeshore into the northern primary snowbelt, though overall conditions won`t be as favorable for a robust lake response at that point, so expect activity by Monday morning to be on the lighter side. With all of this said, hit much of the lakeshore from Erie County, OH points east into PA with likely POPs Sunday afternoon and evening. Bring POPs / QPF inland a bit Sunday evening as the winds turn more northwesterly, with POPs / light QPF then focusing up the eastern shoreline by early Monday as the ridge approaches and winds turn more westerly. Have 1 to locally 4" of snow in the grids from eastern Erie County, OH points east through the snowbelt Sunday afternoon through early Monday, but given what will be a fluffy snow if any organized bands develop Sunday evening I don`t want to rule out a locally higher amount. Given the light flow, expect greatest snow accumulations to occur fairly close to the lakeshore overall. The large area of open water east of the islands may help focus accumulations as far west as Erie and Lorain Counties. Models may struggle with this one given they`re initializing with an icy lake and under-doing the flux off of it, so a tricky forecast with low confidence, but potential is there for travel impacts near Lake Erie Sunday afternoon and evening. Aside from lingering lake effect near the eastern lakeshore Monday morning, expect a cold but dry day. A clipper grazing the region to the north may try scraping extreme northeast OH and northwest PA with snow showers Monday night, but the rest of the area looks dry with any snow with this system in the far northeast minimal. && .LONG TERM /TUESDAY THROUGH FRIDAY/... High pressure in control Tuesday and Wednesday with a return flow developing and moderating temperatures expected. Next item of interest is a wave of low pressure that will develop over the southern Plains on Wednesday and track towards the area Thursday into Thursday night, departing on Friday. For now am still expecting mainly or all rain through Thursday, though models have trended farther southeast with the track of this low so can`t rule out some areas (especially northwestern Ohio and points east near Lake Erie) trying to flip to snow Thursday or Thursday night as the low moves by and colder air starts to return. While we`ll monitor the track of the low for potential wintry implications, still feel most of the QPF is likely to fall as rain at this point and that an outcome similar to last week`s winter storm is quite unlikely. Of greater concern is flooding...decent confidence in 0.75-1.50" of QPF with this whole package late Wednesday or Wednesday night through Thursday night (which is when the bulk of precipitation looks to occur), with a lower potential for 1.50-2.50" shown on ensemble guidance. The snowpack holds an inch or less of water east of I-77, but is estimated to hold 1-2" of water to the east, with locally over 3" in the snowbelt in northeast OH / PA. Some gradual melting has occurred this week and a bit more will occur early next week, with the potential for a more rapid melt Wednesday and Thursday. It`s possible all of the water in the snow doesn`t get released at once, but still enough meltwater likely getting released that some flooding concerns will exist the second half of next week. Questions about whether or not we get higher-end QPF, along with questions about how quickly the water in the snow pack gets released, precludes confidence in a significant flood threat for now, but feel that at least some minor flooding on some area rivers will be hard to avoid unless we trend towards a much colder system or towards much less QPF. Will also need to monitor frozen rivers for ice jam issues as temperatures moderate next week. Greatest overall concern for flooding will be where snowpack is greatest in eastern OH and into PA. Plenty of time to iron out details, but if you are in an area prone to river flooding be sure to check back on this situation as we head into next week and gain confidence in any details. Temperatures approach normal on Tuesday, with highs in the 40s and 50s for Wednesday and Thursday. Temperatures return towards more seasonable values into Friday as colder air moves in behind the low pressure. && .AVIATION /00Z Saturday THROUGH Wednesday/... Generally MVFR conditions exist across the TAF sites this evening with a few, brief pockets of VFR possible over the next several hours into the first half of tonight. Light rain showers have been observed across some of the eastern TAF sites, though no vsby restrictions have been noted at this time. Any IFR ceilings should not last more than an hour or two. MVFR conditions are expected to persist through much of the TAF period, generally associated with lower ceilings. The best chance for any IFR conditions would be at ERI late tonight into Saturday morning from reduced vsbys in snow showers. Scattered snow showers may also impact CLE/CAK/YNG and will need to be monitored for any adjustments to IFR vsbys. VFR may begin to appear towards the end of the TAF period across the western TAF sites. Southwest winds continue to be gusty this evening, 20 to 30 knots. Isolated pockets of 30 to 35 knots have also been observed ahead of the rain. Southwest winds will begin to decrease into the 10 to 15 knot range later tonight, becoming more westerly by Wednesday morning. West to northwest winds of 10 to 15 knots will then persist through Wednesday. Outlook...Non-VFR possible in snow showers Saturday into Sunday. Non-VFR may persist Sunday night into Monday across NE OH and NW PA. && .MARINE... Gusty southerly winds will turn more northwesterly into Saturday morning and then subside over the weekend. Southerly winds will increase Wednesday and Thursday of next week, turning more northerly into Friday. Expect some ice growth over the nearshore waters this weekend, though the milder weather and southerly winds next week will cause renewed movement of the ice away from the southern shore. As has already been said over the last week, the ice on Lake Erie will not be a safe place to be anytime soon and it`s strongly advised to stay off of it. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...None. && $$ SYNOPSIS...Garuckas NEAR TERM...Garuckas/Kahn SHORT TERM...Sullivan LONG TERM...Sullivan AVIATION...Kahn MARINE...Sullivan
Area Forecast Discussion
National Weather Service Flagstaff AZ
904 PM MST Fri Feb 11 2022 .SYNOPSIS... Tranquil and warm weather continues across Arizona through Monday. Expect periods of gusty northeast winds through Saturday, with lighter winds Sunday and increasing southwesterly winds Monday and Tuesday. A more active pattern is possible for the early to middle parts of next week. && .UPDATE...Another quiet night is unfolding across northern Arizona outside of gusty northeast winds along and south of the rim. Expect gusty northeast winds to continue in these areas through Saturday morning with lighter winds returning by the afternoon. The current forecast handles this well with no updates needed this evening. && .PREV DISCUSSION /208 PM MST/... The upcoming weekend will be warm with daytime high temperatures ranging between the 50s to near 80 degrees toward southern Yavapai County. We`ll need to contend with some blustery overnight/early Saturday morning conditions, particularly along the Mogollon Rim, the White, Black, and Bradshaw Mountains thanks to a diffuse shortwave trough diving southward through the Four Corners. While the RAP model is the most aggressive with 50 knot 700mb flow Saturday morning, experimental NBM probabilistic guidance appears to advertise reasonable magnitudes for wind gusts (though I`ve tapered these down) with peak gusts of around 35-40 knots through at least midday Saturday at the higher elevations. With weaker northerly flow and no indication of any additional shortwave troughs rippling through the remainder of the weekend and into early next week, we`ll be looking at largely fair weather across the High Country. Toward the middle of next week, confidence is high that a pattern shift will transpire. There`s still some uncertainty regarding the ultimate track of the upper low which will dictate precipitation chances and amounts. What is for certain is that high temperatures Wednesday through the end of the week will fall 10 to 15 degrees below normal and so it`ll feel like winter across the area. Southwesterly winds will also increase with speeds between 20 and 30 mph Tuesday and Wednesday. Gusts close to 45 mph are expected. It does appear that enough of the deterministic and probabilistic model guidance has slowed the ejection of the main upper trough as blended guidance has trended upward just a touch with advertised PoPs. Standardized anomaly PWAT values return to near normal levels and while I don`t anticipate a widespread significant precipitation event, the official forecast PoPs have increased from the last forecast iteration. This is especially true for areas along the southwest aspects of the higher terrain. PoPs generally range between 30 and 70 percent across the area late Tuesday and into early Thursday. From a kinematic standpoint, the upper trough is impressive in just about all of the major deterministic NWP as 150 to 200 meter height falls are progged to expand across Northern Arizona. Southwesterly 500mb flow also strengthens to magnitudes in excess of 50 knots late Tuesday and into Wednesday. While moisture content for widespread precipitation isn`t ideal, it`s quite possible that the orographic ascent may augment what would otherwise be a largely underwhelming event. Given the enhanced upslope flow, the greatest PoPs run from areas along the Rim (including Flagstaff), back toward the southeast (just north of Payson), and into the White Mountains. From a probabilistic standpoint, there appears to be a good chance (60%) of seeing at least an inch of snow across the aforementioned geographic zones with a 60-70% chance of 2-3" of snow across the White Mountains. The White Mountains and parts of the rim could be beneficiaries of a second shortwave trough that slides southward early Thursday. Again, any shift in the track of the upper lows could result in changes to the PoP, QPF, and expected snow amounts, so check back for updates to the forecast. && .AVIATION...For the 06Z package...VFR conditions prevail through the TAF period. North/northeast winds at 10-15 kts with gusts 20-25 kts will be possible over the high terrain. Winds should calm after 00Z Saturday. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER... Warm and dry conditions are expected. Winds continue from the north/northeast Saturday, especially along and south of the Mogollon Rim, with light winds Sunday. Monday through Wednesday...Continued warm and dry conditions are expected Monday. Winds increase from the southwest Monday and Tuesday ahead of an approaching system, with chances for precipitation increasing late Tuesday. Precipitation moves from the northwest towards the southeast through Wednesday with winds shifting from the southwest to the west. && .FGZ WATCHES/WARNINGS/ADVISORIES...NONE. && $$ PUBLIC...ET/Bain AVIATION...ET FIRE WEATHER...Kobold For Northern Arizona weather information visit
Area Forecast Discussion
National Weather Service Goodland KS
850 PM MST Fri Feb 11 2022 .SHORT TERM...(This evening through Sunday) Issued at 205 PM MST Fri Feb 11 2022 At the beginning of the short term period, current RAP analysis shows the CWA having a northwesterly flow aloft being underneath the back part of a trough. Radar data is showing some echoes moving from the north into southwestern NE though current obs do not show precipitation reaching the ground in the CWA or in the nearest adjacent counties. Satellite imagery shows cloud coverage over most of the CWA with high clouds moving eastward and lower clouds traveling to the south-southeast. From the obs, winds are still gusting up around 35 kts from the north-northwest. Due to these winds and precipitation potential, brief snow squalls may be possible lowering visibilities in the northern two rows of counties in the CWA as this occurred with precipitation outside north of the CWA this afternoon. Later Friday, models show the upper air flow transitioning to north-northwesterly as the trough base moves just south of the CWA. At the surface, chances for quick light snow shower moves from north to south across the CWA along the leading edge of a second burst of cold air moving into the CWA from the north. Minimal accumulation looks to be expected should precipitation. Overnight low temperatures on Friday look to be in the middle teens with wind chills in the single digits. On Saturday, model guidance shows the CWA underneath the back part of the trough with a northerly to north-northwesterly flow aloft throughout the day. At the surface, dry conditions are expected with generally westerly winds as a surface low moves southeast through the eastern portion of NE during the evening. Daytime highs on Saturday look to be in the middle 40s while overnight lows range from the upper teens to lower 20s. For Sunday, the CWA has a northwesterly flow aloft as a ridge in the western CONUS moves eastward throughout the day putting the CWA underneath the front part of the ridge. At the surface, the CWA continues to see dry conditions with possible elevated fire weather conditions along and west of the CO border with minimum RH values in the upper teens. Winds may come close to reaching criteria in these areas with gusts exceeding 20 kts during the afternoon may be possible. This situation will be monitored to see if conditions change. Daytime highs for Sunday expect to be in the upper 40s to upper 50s followed by overnight lows in the lower to upper 20s range. .LONG TERM...(Monday through Friday) Issued at 146 PM MST Fri Feb 11 2022 In the extended... Period will begin with low amplitude ridging in place across the CWA with main concern being several cold frontal passages intruding on the area. While there may be a window between the cold fronts where fire weather could be a concern due to intensifying winds, confidence with respect to the timing of each feature remains very low. Low confidence continues into the later half of the week as the next storm system takes aim at the southern plains. Operational models and their ensemble clusters seem to be in two general camps, a progressive open wave or a closed, slower and more intense system. While the second scenario would definitely give the region the potential for heavy snow, strong winds and numerous other impacts, hard at this point to say that is a favored or even most likely solution. Given the large amount of uncertainty present in the upcoming system, I think it is reasonable to say there is a good chance for accumulating snow in the Wednesday night to Friday morning time frame. For those with travel our outdoor interests, please stay aware of the latest forecast for this time period as details become clearer. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 850 PM MST Fri Feb 11 2022 KGLD...VFR conditions are currently expected through the period. A north wind around 10kts at taf issuance will gradually back to the northwest at similar speeds around 10z then to the west-northwest around 13kts at 16z. Occasional northwest winds gusting up to 25kts or so are expected from 18z-20z. From 21z-04z a west wind around 10kts is expected, veering to the west-northwest around 12kts at 05z. Streamers of low clouds and sub VFR conditions are possible from taf issuance through about 10z as they move from northwest to southeast across parts of the forecast area. KMCK...VFR conditions are expected through the period. A northwest wind up to 10kts at taf issuance will back to the west around 6kts by 11z and continue through 16z. From 17z-21z west winds occasionally gusting up to 25kts or so are expected. From 22z through the rest of the period, winds slowly veer to the northwest around 10kts. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...076 LONG TERM...JRM AVIATION...99
Area Forecast Discussion
National Weather Service Gray ME
950 PM EST Fri Feb 11 2022 .SYNOPSIS... A cold front will approach the area from the west tonight before crossing the region on Saturday. This will bring a few rain and snow showers late tonight and on Saturday morning. Temperatures will climb well above normal again on Saturday before much colder air returns behind the front Saturday night. High pressure will build in for the first half of next week with temperatures below normal as a coastal storm misses the region to the south and east. Temperatures moderate by the second half of next week. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... 0245Z Update... Latest update was to once again adjust hourly temperatures as some areas have decoupled while most others have not. A southern wind has increased in response to a strengthening jet aloft, allowing more areas to climb through the 40s this evening. Radar continues to indicate echoes across mainly northern portions of the forecast area. Latest observations and most webcams across the region only showing some flurry activity across the higher terrain of the north. This appears to be realistic based on 00Z GYX sounding which indicates dry air in the lower and middle portions of the atmosphere, up to around 600 mb. Nevertheless, as moisture continues to advect into the region, scattered snow showers can be expected over the higher terrain with light accumulations above 2000 feet. For the rest of the region, light rain showers may gradually spread mainly towards central portions of the forecast area by later tonight. Update... Temperatures continue to fall very slowly this evening as warm air advection increases over the forecast area. Temperatures will follow with remaining steady or slowing rising during the overnight hours as a low level jet develops over the region. Mid level moisture will continue to advect into the region this evening per latest surface observations and HREF solution. Echoes continue to mostly remain over northern New York State and Vermont this evening. As low pressure rides east through Canada, precipitation will mainly be confined to far northern portions of the forecast area. This is supported by the latest HRRR and 3 km Nam solutions. Prev Disc... High Impact Weather Potential: Minimal. Pattern: Early afternoon water vapor imagery shows an amplifying trough over the Great Lakes region with a longwave ridge just off the west coast of North America. Associated with the trough is an area of surface low pressure centered over the upper peninsula of Michigan which is gradually moving north and east. This places northern New England in the warm sector south and east of the surface low with ongoing warm advection allowing spring- like temperatures to flow into the area. For the near term forecast period...the aforementioned surface low will move well north of the region...with a surface cold front reaching the eastern Great Lakes by daybreak Saturday. Thus...the primary forecast focus will be on any shower potential as the front nears from the west...and surface temperatures as these showers arrive. Through this evening...High clouds will continue to increase as the shortwave trough to our west slowly approaches. Temperatures won/t fall very far...remaining in the upper 30s and lower 40s south of the mountains by 7pm with readings falling back into the lower/mid 30s to the north. Tonight...Low pressure over the Ontario/Quebec border this evening marches north and east overnight with top down saturation occurring across our area ahead of the upstream shortwave trough. Moisture deepens with PWATs pushing above 0.5" but best +DPVA brushes our northern zones with westerly component of the flow favoring little in the way of precipitation south of the mountains with weak downslope component. Thus...will paint highest PoPs in the mountains /chance to low likely/...chance in the foothills...and slight chance to the south and east. Temperatures will be marginal for rain and snow up north with a few sprinkles the most likely Ptype south of the mountains. It will be a mild night with strengthening gradient keeping the area coupled with an impressive LLJ just off the deck /50-55kt at H9/. Thus... expect temperatures to fall little after this evening... remaining in the lower/middle 30s of the mountains...and the upper 30s to lower 40s to the south. Any precipitation will be light /generally less than 0.1"/. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... High Impact Weather Potential: Minimal. Pattern: A surface cold front passes through the region on Saturday and then offshore Saturday night. Our first focus is therefore on shower potential with the front as well as temperatures ahead of the frontal passage. Cold advection will continue Saturday night with the focus shifting to colder temperatures. Saturday: Surface cold front arrives from the west...crossing the CWA in the afternoon. 0.5-0.7 inch PWAT plume overhead in the morning will fold east before cold/dry advection ensue. Best shower chances...therefore...will be in the morning with activity increasingly becoming confined to the upslope areas in the mountains as the deeper moisture heads east. The timing of the front indicates that we/ll sneak in one more mild day as T9s ahead of the boundary push towards +5C across southern areas and +2-3C in the north. This would support mid 50s under full mixing and though there will be some cloudiness...only went below the fully mixed values a tad given what should be good mechanical mixing and some glimpses of sun. Thus...lower 50s should be widespread south of the lakes region in NH and far southwestern ME with 40s elsewhere. Saturday Night: Cold/dry air advection continues under westerly flow with remaining mountain snow showers coming to and end and a partly/mostly clear night expected. CAA will drive lows back towards zero along the international border with teens and 20s for areas to the south and east. The guidance consensus has this idea well covered and was followed in the forecast. && .LONG TERM /SUNDAY THROUGH FRIDAY/... Long-range models continue to show disruptions to the +PNA pattern at 500 MB that settled in for much of the the 2nd half of January, as blocking over the E Pacific breaks down and allows waves to move onshore into W NOAM. It`s not a complete breakdown, but it is likely to put us back into a more changeable pattern with alternating warm and cold spells through next week and into next weekend. Only threat for more signify precip will be toward the end of next week, but this looks like it will be warm enough that p-type will be mostly rain, perhaps even into the mtns, although at this time range confidence on p-types is still low. Sunday we`ll see southern stream energy move out of the gulf states toward the Grand Banks, while lagging nrn stream trough moves across the area Sunday night. This will mostly be a miss as far as precip goes although interaction between these systems could produce some light snow on the NW side of the storm which may bring a short period of light snow or snow showers mainly to areas near or just inland of the coast. Highs Sunday will be in the 20s to around 30. Behind this system the core of the coldest air will move in for Monday. when highs will be in the teens to around 20, despite mainly sunny skies. Mon night lows will drop to around -10 in the mtns and generally -5 to +5 in the south. Sfc high passes over Tuesday and Wed and Tue will be warmer than Monday but still below normal with highs in the 15-10 in the mtns and 25-30 in the south. As the sfc high shifts offshore Wednesday, return flow should allow temps to jump up by 5-10 degrees on Wed with highs mostly in the 30s. 500 MB ridging builds in for Thu as 500 mb low closes off over the srn plains, but also stretches out to the NE. This will allow fairly decent mid-lvl baroclinic zone to develop just to our N. This puts us on the warm side, and could see highs reach into the 50s in many spots of Thursday, but it comes with a lot of clouds and rain showers. Models then develop series of weak sfc lows along this boundary, which will bring steadier precip into the region Thu night and Fri, and again this will be mostly rain, but may see lowering snow levels in the mtns on Friday. Still a lot of time between now and then, so plenty of time for models changes. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Short Term... Summary: A cold front will approach the region tonight...passing through the area on Saturday. This will bring some lowering clouds and some potential for a few showers. Restrictions: VFR conditions will largely dominate the TAF period. Ceilings will lower late tonight through much of the day on Saturday with the greatest threat for restrictions being in the mountains /HIE/ where a rain shower is possible. Winds: Southerly winds around 10kts will diminish to 5-10kts tonight before strengthening from the southwest and west on Saturday 12g18kts before veering northwest around 10kts for Saturday night. LLWS: Southwest winds at 1.5kft increase to 45kt tonight with LLWS for the overnight period throughout the area. Long Term...Some MVFR possible in low cigs and light SN at coastal terminals Sunday, but otherwise VFR expected Sun night through Wednesday. && .MARINE... Short Term...Have included all of the waters in SCAs for tonight based on latest observations and forecast conditions. Long Term...SCAs will likely be needed late Sunday into Sunday night in NW flow, and then again on Wed in SW flow. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 7 PM EST Saturday for ANZ150>154. && $$ NEAR/SHORT TERM...Cannon LONG TERM...Cempa
Area Forecast Discussion
National Weather Service Louisville KY
940 PM EST Fri Feb 11 2022 .Forecast Update... Issued at 935 PM EST Fri Feb 11 2022 Double-barrel fropa is underway as the first cold front has pushed southeast through most of central Kentucky and is now just NW of the Lake Cumberland region, while the secondary boundary is just south of Interstate 70 across Illinois and Indiana. In between a band of light rain has been left behind, and is moving more slowly than previously advertised. Will bump POPs for the next couple of hours near and just south of the Ohio River, but there is a notable weakening trend to our west as this precip tries to push through. Should just be a chilly rain with amounts around a tenth of an inch, if that. As we get deeper into the night, still expect to come into line with the going forecast. Updates on the way shortly. Issued at 600 PM EST Fri Feb 11 2022 Winds are gradually diminishing across central Kentucky, with only a few spots along and just north of the I-64 corridor still touching Advisory thresholds. With the cold front now dropping through southern Indiana, and the sun setting, would not expect that to last long enough to merit extending the Wind Advisory, so will let that headline expire on schedule at 23Z. Minor tweaks to the timing of the band of light rain that will accompany the cold front, but otherwise the previous forecast is fairly well on track. && .Short Term...(This evening through Saturday) Issued at 254 PM EST Fri Feb 11 2022 Winds have gusted into the 40-50mph range this afternoon, but those gusts will be dropping off quickly late this afternoon as cloud cover increases and the sun sets. We have flirted with higher fire danger in our southeast (Lake Cumberland/southern Blue Grass) but so far fuel moisture has remained just high enough for most of the day and most areas have experienced generally high enough humidity to preclude needing a Red Flag Warning. RH and fuel moisture are lower over eastern Kentucky. A cold front stretching from Michigan to Texas will push southeast through the Ohio Valley this evening accompanied by a band of light rain and precipitation amounts less than a quarter of an inch. Can`t rule out a few snowflakes as the precipitation ends late tonight but no impact is expected. Morning lows will range from the mid 20s in southern Indiana to the mid 30s around Lake Cumberland. Winds will keep up around 10-15 mph and help to dry off any wet roads. Saturday cold air advection will bring flow off the Great Lakes into the middle and upper Ohio Valley, and we`ll be ahead of an approaching upper trough axis. Moisture will be very limited under a strong inversion. Will account for a small chance of isolated light snow showers, which is supported by the HRRR and RAP, but most locations will likely stay dry. The best chance for a snow shower will be along and north of I-64. It will be a chilly day with winds coming in from the northwest around 10-15 mph and afternoon highs in the 30s. .Long Term...(Saturday night through Friday) Issued at 300 PM EST Fri Feb 11 2022 Synoptic...The long term forecast starts with broad cyclonic flow aloft as a trough axis is oriented SW-NE from the Great Lakes towards the Gulf Coastal Plains. Dropping from the Canadian Prairie provinces, an upper-level low opens up at the same time it swings by the upper Ohio Valley. The accompanying low pressure and cold front are relatively weak, so no major changes are expected during the weekend. Thereafter, surface high pressure and zonal westerlies support a dry and cold spell for KY and IN. However, the mean wave pattern will change by the middle of next week as the long-anchored above-average heights over the Western US retreat to the Pacific and an amplifying trough/closed low settles in. As a result, the preferred corridor of frontal waves will be located from the Southwest US to the Great Lakes, opening the possibility of heavy rain and thunderstorms in the Ohio Valley. Saturday night-Sunday...Arctic post-frontal airmass lowers temps to the upper teens on Sunday morning. Despite some sunshine during the first half of the day, the aforementioned cold front will slightly increase precipitation chances in the afternoon and early evening. Below-freezing thermal profiles along the vertical and saturation in the lowest layers (including the DGZ) support snow as this system`s precipitation type. Nonetheless, the limited moisture and DGZ depth combined with the weak mesoscale lifting should only account for uneventful snowfall rates. Highs at the end of the weekend should stay at or near the 32 degrees mark. Monday-Wednesday...Surface high pressure and strong mid-level subsidence will impose blue-sky days by the start of next week. Lows on Monday and Tuesday will stay below freezing, although Monday will be the coldest of the two. There is a notable warming trend between highs on Monday (around 40) and Tuesday (low 50s) due to the wind shifting to a southerly direction. As a shortwave trough and attendant surface low approach from the southern Great Plains, the pressure gradient will tighten and winds will speed up on Wednesday. This resultant WAA will take afternoon temperatures to the low 60s while dewpoints reach the low 40s. Overall, Wednesday should stay dry with increasing high-level clouds. Thursday-Friday...This period is the main focus of the 7-day forecast due to the growing possibility of impactful weather. Models are indicating a phasing between the northern and southern streams. The interaction will take place along a baroclinic wave draped NE-SW across the Mississippi and Ohio Valleys. But as it is characteristic with a forecast this far out, models are struggling with timing and most importantly strength of the northern stream (as highlighted by the 500-hpa EOF guidance). There are two main scenarios to consider: weak vs strong northern trough. If the trough is weaker than expected, then the lower Ohio Valley will maximize the residence time in the warm sector of the upcoming storm system. On the other hand, a stronger trough will push the storm system southward so that the heavy rain axis will fall near southern Indiana and northern Kentucky. Regardless of the main output, anticipate rain and possible thunderstorms to manifest in the second half of next week as the main ingredients for convection will be present. && .Aviation...(00Z TAF Issuance) Issued at 605 PM EST Fri Feb 11 2022 Cold front came through HNB within the last hour with a quick wind shift to NW and light rain, but no restrictions to cig/vis. Ahead of the front we have gusty west winds touching 25 kt at times at SDF and LEX. Expect the same wind shift to push through by mid-evening, with sustained speeds dropping to 10-15 kt and diminishing gusts. Precip type along the front shouldn`t be a problem as it`s just a couple hours of light rain without vis restrictions. However, behind the front a decent stratus shield will build down into MVFR after midnight, but cigs should remain above 2000 feet. NW winds will maintain a steady 10-12 kt for most of the period as diurnal mixing will be cancelled out by the weakening of the CAA surge. Could see a few flurries or snow showers, but not confident enough to include anything more than VCSH and not expecting any further restrictions to ceiling or vis. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...RAS Short Term...13 Long Term...ALL Aviation...RAS
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
923 PM CST Fri Feb 11 2022 .UPDATE... Issued at 920 PM CST Fri Feb 11 2022 This evening`s scattered snow showers have mostly shifted east over Lake Michigan with some lingering isolated light snow showers and flurries across portions of northeast Illinois. We have also had a few reports of some very light freezing drizzle/mist at times. Flurries will likely linger across the area for the next few hours. A secondary boundary, mentioned in the afternoon short term discussion below, is currently making its way south across Lake Michigan. There remains some uncertainty with whether this feature will still add to the longevity of snow shower chances into Cook County. For now, opted to maintain the ongoing forecast for a chance of snow showers lingering a couple hours past midnight into Cook county and the immediate shoreline, with higher chances into northwest Indiana. No changes were made to the lake effect snow forecast into northwest Indiana and more specifically northeastern Porter County through Saturday morning, with 1-3" still possible. Will note that the better chances still appear to be just east of our forecast area into LaPorte County. Lastly, given the quickly dropping surface temperatures below freezing this evening after a warm day with plenty of snow melt, any lingering puddles could freeze over, resulting in patchy slick spots on untreated roadways and sidewalks. Do think that the gusty winds should have helped dry out most roadways to prevent it from being a widespread issue, but something to be aware of. Petr && .SHORT TERM... Issued at 325 PM CST Fri Feb 11 2022 Through Saturday night... The main concerns in the short term center on tonight, with blustery conditions settling in behind a strong cold front. Snow showers will also be seen in parts of the area, mainly northeast Illinois and northwest Indiana, and some of these will probably provide an isolated coating and sharply reduced visibility, including the latter part of the commute in the northern suburbs. Finally, lake effect snow in far northwest Indiana overnight into Saturday morning looks to result in accumulating snow, possibly up to 3 inches, for Porter County. The advertised strong cold front is sweeping eastward through the area as of 3 PM. West-northwest winds immediately behind the front are gusting 35 to 40 mph in north central Illinois. These winds are advecting in colder air quickly with Sterling, IL down 8F in just an hour, for instance. Temperatures are already in the mid teens in northern Iowa and this will advect in here through the night, aided by surface pressure rises on the order of 10-12 mb over just six hours this evening. Wind chills will be in the 0 to -5 range for much of the area by daybreak Saturday. Along the front itself are developing isolated rain showers from the Chicago metro down I-57. These not only have a convective look on radar but also appearance visually, as out the window it resembled more of a late spring day! These showers should largely remain rain, though could have some graupel as they gradually increase in coverage into northwest Indiana after 4 PM. The main attention though is on the batch of snow showers in Wisconsin associated with the low level front and frontogenesis along it, as well as strong upper forcing and PVA above. This forcing, in tandem with steepening low-level lapse rates within cold air advection, should steer this into northern Illinois at least along/north of I-88 through mid-evening. Confidence diminishes on how far south this will spread, although any heavier snow showers would be more favored in the northern locations. Upstream reflectivity and visibilities indicate there are some sub 1 SM, and would not be surprised if briefly under 1/2SM given the concurrent winds and snow. This will likely overlap the latter part of the evening commute in northern portions of the Chicago metro. With accumulations likely to be streaky, and the mild pavement going into this at first, feel that Graphical NOWcasts and other more tactical messaging will address this. Lake effect snow will take over as the more dominant driving method of snow by overnight into northwest Indiana. Prior to that, during the late evening, there is some indication of a secondary trough/wind shift moving down the lake with some enhanced QPF on the HRRR runs. This could provide a pretty good burst of snow accompanied with a re-uptick in the winds, and may even graze the Cook County shore. Evening shift will have to keep an eye on mesoscale trends for this as its tough to say if that will materialize at this point. Into the overnight, multicell lake effect showers are expected into Porter and possibly Lake County in northwest Indiana. Lake-enhanced equilibrium levels will rise up to around 7,000 ft and with the cooling profiles the dendritic growth zone is better intersected. This should continue into Saturday morning, gradually waning late morning into the early afternoon. Accumulations of 1 to 3 inches are forecast for northern and eastern Lake County, but as always with lake effect some variability is expected. Higher amounts, as well as temporary convergence signatures, are better seen in high- resolution guidance signatures further east. Some snow covered roads can be expected through in parts of Porter County to start Saturday. Otherwise on Saturday, northern Illinois should see some breaks of sunshine to offset an otherwise cold day. The 850 mb temperatures are forecast -17C to -20C, and if we had fresh snow cover it would be notably colder. Have highs only 18 to 22 across the area. MTF && .LONG TERM... Issued at 232 PM CST Fri Feb 11 2022 Saturday Night through Friday... Forecast concerns include two weak clipper systems, the first Sunday morning, the second Monday morning and then a large storm system to affect the region the middle of next week with the potential for heavy rain, accumulating snow and possibly a wintry mix. A ridge of high pressure will move across the area Saturday evening as a fast moving clipper system moves from the Dakotas Saturday evening to southern IL by midday Sunday. A narrow band of light snow is expected northeast of the track of this system and currently appears to move across central IL, possibly including the southern half or so of the cwa. Moisture is somewhat limited and the fast movement will limit duration of the light snow but a few tenths of an inch are possible. Blended pops continue to be dry for this time period and continued low chance pops. Even if there isn`t a swath of minor accumulation, flurries will be possible across much of the area. As this system departs early Sunday afternoon, there will be the potential for some lake effect snow showers into far northwest IN. Confidence is fairly low for how long these may persist but did include low chance pops into Sunday evening. Another ridge of high pressure will cross the area Sunday evening and another fast moving clipper will move across the area around or just before daybreak Monday morning. Moisture is even less impressive during this time period but opted to carry low chance pops across the northern half or so of the cwa for this potential. Similar to Sunday morning, its possible that only flurries will materialize. Each of the two high pressures noted above will bring the potential for a sharp drop in temps each evening and then temps may level off as clouds spread in ahead of each system and only medium confidence for lows each morning. The lighter winds should keep wind chill values each morning near zero or higher. High temps on Sunday will likely struggle to reach 20 degrees. After the Monday morning clipper, dry weather is expected through Wednesday morning with highs moderating into the lower 30s Monday and mid/upper 30s Tuesday as southerly flow returns. By Wednesday, low pressure will develop over the southwestern Plains and is expected to lift northeast across northern or central IL Thursday as it accelerates across the eastern Great Lakes Thursday evening. Any precipitation on Wednesday appears to be mainly in the afternoon, mainly rain and generally light, for the daylight hours. Southerly winds may be gusting into the 30-35 mph range. From Wednesday evening through Thursday evening, it remains too early for specifics and small changes in the track of this storm system will have large impacts on where accumulating snow may develop, where any wintry mix may occur and where the heaviest rains may develop. As an example, the 12z operational ECMWF has jogged south slightly and changes like this can be expected for at least the next few days. As for items of concern, precipitable water values approach 1 inch, especially in the southern cwa, even higher further into the warm sector. Storm total qpf from the models have been consistently showing a swath of 1-2 inches, of rain. If this were to materialize over parts of the area, there would be some flooding potential, especially due to localized ice jams given the current river ice coverage. As the colder air settles into the northern side of the system, there will likely be a narrow corridor of a wintry mix, including freezing rain. Unless there were a significant shift north or south with this system, this corridor of a wintry mix could possibly be right across the cwa. And as the system finally departs, there will likely be a final changeover to all snow and given the accelerating forward speed as it departs, snow on the back side could be somewhat short in duration. These are current concerns as the models show now. Again, this time period is too far out for any specific yet. cms && .AVIATION... For the 00Z TAFs... Aviation Forecast Concerns: * Blustery west-northwest winds with sporadic 30+ kt gusts early this evening. * Period of convective snow showers this evening with brief IFR visibilities and minor accumulations. * MVFR ceilings prevail into Saturday, though gradually lift. Strong surface cold front was pushing east across the area late this afternoon, and was moving through the Chicago area terminals as of 530 pm. Blustery west-northwest winds will shift more northwest with time, and will be accompanied by sporadic 30-35+ kt gusts briefly this evening. A period of convective snow showers behind the front will also bring brief periods of IFR visibilities and some quick minor accumulations, though lowest conditions will be be somewhat hit and miss due to their scattered nature. Snow shower intensity should diminish later this evening, though flurries and lighter snow showers persisting past midnight. KGYY may see a little longer period of snow showers as lake effect develops overnight, though the focus for heavier lake effect snow showers should be largely east of KGYY especially toward morning. Otherwise, MVFR ceilings will likely persist well into Saturday, though with a gradual increase in cloud base heights above 2500 feet. Northwest winds will gradually diminish during the day, eventually settling below 10 kts by Saturday evening. Ratzer && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...Small Craft Advisory...IN nearshore waters until 9 PM Saturday. Small Craft Advisory...IL nearshore waters until 3 PM Saturday. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Mobile AL
623 PM CST Fri Feb 11 2022 .UPDATE...Upon further review of model guidance for dense fog tonight, decided to issue a Dense Fog Advisory for areas along and west of the Alabama River (including Clarke and Baldwin counties in AL). In addition, a Marine Dense Fog Advisory was issued for Mississippi Sound and Mobile Bay. Both Advisories go into effect at midnight tonight and continue through mid-morning on Saturday. Take caution if traveling or boating tonight and tomorrow morning! /26 && .AVIATION... 00Z issuance...VFR conditions were present at the TAF sites at issuance and will continue at least for the first part of this evening. Conditions will then begin to deteriorate late this evening and into the overnight hours due to the development of fog. Locations along and west of the Alabama River including the Mississippi Sound and Mobile Bay will likely see dense fog development by late tonight, with more patchy to areas of fog anticipated over the Florida Panhandle and south-central Alabama. In terms of the TAF sites, dense fog will therefore most likely impact MOB and BFM, but not so much at PNS. Model guidance indicates that this fog has the potential to linger into mid- morning Saturday, so VFR conditions are not expected to return until late morning to early afternoon. Light winds overnight will increase to around 5-10 knots and shift to be northwesterly by Saturday afternoon. /26 && .PREV DISCUSSION... /issued 438 PM CST Fri Feb 11 2022/ NEAR TERM UPDATE /Now Through Saturday/...The axis of the weak shortwave trough moving east across the region today will be east of the area by this evening. An area of light showers associated with this feature over the Gulf is dissipating and will continue to move off to the east. This area of precip mainly remained offshore. A scattered to broken mid level cloud deck over the Gulf and the southern half of the forecast area will be east of our area by this evening. A dry, zonal to southwest flow aloft returns tonight and continue through Saturday in the wake of this feature. The deep layer dry airmass will remain entrenched across our area through Saturday, with precipitable water values ranging less than 0.6" across our region. A somewhat variable light wind flow will continue across the area as a weak surface ridge axis remains oriented along the north central Gulf Coast. The next front will be approaching the Mississippi Valley region by late Saturday, with clouds increasing, but the still dry mid levels should inhibit any precipitation as the front approaches. There is some return moisture at the very lowest levels of the atmosphere though, and forecast soundings late tonight indicate a very favorable profile for the development of patchy to areas of fog over much of our region with the still very dry airmass aloft over the saturated airmass right at the surface. Conditions look favorable for possible areas of dense fog development late tonight into early Saturday morning, but mid and upper level cloud cover could be a hindrance. Later shifts will need to monitor trends overnight for a potential Dense Fog Advisory issuance. Not quite as chilly tonight, with lows mainly in the low to mid 40s over inland (a few upper 30s possible in some normally colder locations) areas and ranging from the mid 40s to near 50 degrees along the immediate coast and beaches. High temperatures on Saturday continue to look mild as the front approaches from the west, topping out in the upper 60s to lower 70s at most locations (perhaps mid 60s over northwestern zones which will be closest to the approaching front). /12 SHORT TERM /Saturday night Through Monday night/...Overall the short term should be dry for most of the area despite a positively tilted trough moving across the area Saturday night into Sunday morning. However, as prior shifts have noted there could be a chance of a wintry mix to some light snow (flurries to maybe light dusting) possible along and north of highway 84. Upfront, this forecast seems very simple in that no precip will occur as the main upper shortwave centered over the great lakes and the southern stream shortwave are just not in phase with each other leading to weak ascent in a rather dry regime. Unfortunately, like many other forecasts before, it can never be that easy. Majority of the guidance has trended towards the drier solution with the out of phase troughs, then this afternoon the 18Z High-Res Rapid Refresh (HRRR) decides to spite all forecasters around the area. Why you ask? Well, the 18Z HRRR is much quicker with the southern stream shortwave and allows for a much better phase between the two troughs. The result is a band of moderate 850mb to 700mb frontogenesis overlapping a slightly moister environment and cold profile. This area of frontogenesis would result in a quick moving band of moderate precip after midnight Saturday through Sunday morning. Given precip rates, evaporative cooling would allow for an all snow profile and some dusting would be likely across areas along highway 84 and north. While we mainly just kinda had a chuckle in the office about it and no forecast should ever go off 1 run of 1 model it does hint at what trend in guidance we would have to see in order to get wintry precip. Given the trend in 99.9% of the guidance, we elected to remove the mention of wintry precip from the grids; however, if more guidance begins to trend towards the more in phased troughs like the HRRR is showing then we may have to consider re-adding the wintry mix with later issuances. Probability of this scenario happening seems low (10% ish) and decreasing; however, there`s still a tiny chance for you snow lovers. After that whole debacle the trough pivots through pushing a surface cold front across the area leading to a dry and cool Sunday through Monday night. Surface northerly flow and high pressure aloft will keep skies clear. Temperatures will be cooler with highs climbing into the low 50s on Sunday and mid to upper 50s on Monday. A few locations could see low 60s by Monday as the surface cold advection relaxes. Lows will be in the upper 20s to low 30s Saturday and Sunday night before slowly beginning to increase into the mid 30s on Monday night. BB/03 EXTENDED TERM /Tuesday Through Friday/...Zonal flow aloft transitions into southwesterly flow early next week as an upper level ridge begins to build in over the Caribbean. Meanwhile, a developing upper level trough begins to dig across the western and central CONUS. Surface high pressure is expected to dominate across the eastern U.S. before moving out over the western Atlantic on Wednesday. The progression of this surface high will cause winds to become southeasterly which will enhance warm, moist advection off of the Gulf waters on Tuesday and Wednesday. With the surface high in place, dry and pleasant conditions will continue for the early part of next week. Temperatures will also trend warmer as a result of the southerly flow with highs reaching the mid 60s to lower 70s. Although, lows will still be rather chilly at night with temperatures falling into the upper 30s inland to the mid 40s along the coast. By Wednesday evening and into Thursday, conditions begin to change as the aforementioned upper level trough becomes unphased and a potent shortwave approaches the Plains and Mississippi Valley. At the surface, a low pressure develops over the Central Plains and tracks northeast and will bring a cold front through the region sometime Thursday and Thursday night. We`re continuing to monitor this system for the potential of severe storms and a flood threat, but at this point in time it is difficult to iron out the specifics for any hazards. Overall, guidance is in pretty good agreement with this shortwave taking on a negative tilt on Thursday with a strong upper level jet. A diffluent pattern aloft also sets up which would support lift across the region. Additionally, a strong low level jet looks develops over the region on Thursday which would further enhance the warm, moist advection off of the Gulf. Bulk shear does not look hard to come by at this point with instability looking slightly more present than in previous updates. We`ll continue to monitor these trends as we get closer, but overall showers will be on the rise as we head into mid next week with the potential for some strong to severe storms. Temperatures continue on the warming trend through Thursday, before drier and cooler conditions return in the wake of the cold front. /14 MARINE...A weak ridge of high pressure will remain over the marine area through Saturday. Winds becoming light southeasterly to southerly through this evening. Winds will turn more westerly late tonight ahead of an approaching cold front. Patchy fog may impact area bays and sounds again late tonight into Saturday morning. A strong northerly flow is expected Saturday night into Sunday following the passage of the front. Conditions will become hazardous for small craft over the weekend, and Small Craft Advisories will likely be required for at least the Gulf marine zones during the latter part of the weekend, with no less than Exercise Caution levels (possibly SCA) for the bays and sounds. /12 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...Dense Fog Advisory from midnight tonight to 9 AM CST Saturday for ALZ051>053-261>266. FL...None. MS...Dense Fog Advisory from midnight tonight to 9 AM CST Saturday for MSZ067-075-076-078-079. GM...Dense Fog Advisory from midnight tonight to 9 AM CST Saturday for GMZ630>632. && $$ This product is also available on the web at:
National Weather Service Morristown TN
800 PM EST Fri Feb 11 2022 .UPDATE... EVENING UPDATE. && .DISCUSSION... Dewpoints remain fairly steady state this evening, but RH values have risen above 30 percent most everywhere this evening thanks to falling temperatures. Winds have also come down significantly as well. All this to say that red flag conditions are no longer being seen and went ahead and dropped the warning. For the overnight hours, winds will remain elevated as a cold front approaches from the west but will be far less than what was seen today. In light of today`s guidance performance, felt it was necessary to massage overnight dewpoints and temperatures. NBM guidance seems too high on the former, and too low on the latter, though mainly over the plateau in that regard. For dewpoints, did a blend of current forecast with HRRR and the NBM 10th percentile which fit current obs very well and seemed to be indicative of what upstream dewpoints would advect in overnight. On the temperature side of things, leaned more heavily towards the CONSShort which warmed lows up a degree or two across the board, with more notable increases over the plateau areas. Didn`t make any changes to the forecast tomorrow as it seems to be in good shape at the moment. CD && .AVIATION... 00Z TAF DISCUSSION. VFR flight categories are expected through the overnight hours, then lower into MVFR territory for KTYS and KTRI after daybreak tomorrow as the cold front and precipitation moves in. Will mention SHRA or VCSH at those locales too. KCHA likely remains VFR and rain free. High pressure builds south into Arkansas tomorrow so should see winds remain NLY to NWLY. This would yield downslope flow off the plateau into KCHA as well which further gives confidence in lack of MVFR CIGS there. CD && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 46 55 26 44 22 / 10 10 0 10 0 Knoxville McGhee Tyson Airport, TN 45 52 27 41 20 / 10 20 20 10 0 Oak Ridge, TN 44 50 25 42 19 / 10 20 20 10 0 Tri Cities Airport, TN 42 50 28 38 18 / 10 30 40 20 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Pocatello ID
759 PM MST Fri Feb 11 2022 .UPDATE... Seeing several observations including Idaho Falls and Burley falling to 1/4sm visibility already this evening. Most of the models don`t show fog developing until later and then keeping it mainly patchy. Think most of the models may be too dry as our forecast lows in the Snake Plain could be too cold although didn`t raise the lows. The HRRR seems to have a better idea of where the fog is as it expands rapidly from the INL region out to the interstates which is what we`ve seen this evening. Have issued a dense fog advisory until 17z. Some light icing on roadways is possible, but as last night expecting that visibility will be the main concern. 13 && .PREV DISCUSSION... /issued 136 PM MST Fri Feb 11 2022/ SHORT TERM...Tonight through Saturday night. Satellite imagery shows significant erosion of the moisture trapped under the inversion this afternoon. Observations show considerable improvement in visibility as well, so have opted to cancel the Dense Fog Advisory. Model soundings continue to favor a mix of stratus and fog, and guidance still indicates potential for at least locally dense fog in the Lower and Upper Snake Plain, but spares the remainder of the region. Thus opted to broadbrush patchy dense across the forecast for late tonight and will hold on issuing another Dense Fog Advisory for now. A potential repeat is expected Saturday night. DMH LONG TERM...Sunday through next Friday. Upper ridge remains in place through Sunday. Next upstream Pacific trough advances into the NW coast late Sunday night and splits as it moves onshore across the NRN Great Basin/Rockies Monday night/Tuesday. Typically we don`t get a whole lot of moisture from splitting systems as they work through the region and will float along with the National Blend of Models here which shows some fairly decent precipitation potential for the event with light to modest snow accumulations favoring the mountains. Secondary energy trails across WRN Montana Wednesday which is expected to provide ongoing support for snowfall across the mountains through early Thursday morning. It looks like the ridge rebounds across the region late next week and heading into the early part of the weekend for a return to an inverted temperature regime and drier conditions. Huston AVIATION...Per the latest satellite imagery, it looks like the fog and stratus are solidly entrenched across the Snake River Plain and adjoining mountain-valley locations. Model time sections continue to hint at some erosion occurring later this afternoon and terminals may yet see a break in the LIFR CIGS and VSBY but as time goes on, my optimism is fading on this point. Even if we do get a break late this afternoon, it will likely be short-lived with fog redeveloping across the region late tonight impacting all terminals but perhaps KSUN and KBYI. Huston && .PIH WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 10 AM MST Saturday for IDZ052>055. && $$
Area Forecast Discussion
National Weather Service Phoenix AZ
505 PM MST Fri Feb 11 2022 .Update...Updated Aviation Discussion. && .SYNOPSIS... Strong high pressure situated along the West Coast will result in clear skies and well above normal temperatures through early next week. High temperatures in the upper 70s to as warm as 85 degrees are expected through Monday with no chance of precipitation. A weather system is then expected to move through the region next Tuesday and Wednesday bringing locally windy conditions, chances for light precipitation, and pushing temperatures back to below normal for the latter half of next week. && .DISCUSSION... Latest water vapor imagery and RAP streamline analysis reveal a broad ridge positioned off the California coast. Northerly flow around the ridge is resulting in a continuation of the sunny skies and seasonably dry conditions across the Desert Southwest. While the strongest EFI temperature values are concentrated in California, high temperatures as much as 10 to 15 degrees above normal extend into portions of Arizona. However, probabilities for record breaking temperatures are less than 5 percent today, even in areas such as El Centro, California. For tonight and early Saturday, a strong surface high building across the Rockies will again result in breezy conditions, particularly across the foothills of the Tonto National Forest. Ensemble model suites remain in exceptionally good agreement over the next several days, depicting the aforementioned ridge persisting across the intermountain West, but gradually weakening. Latest guidance indicates the above normal temperatures will continue through Tuesday. Thereafter, an anomalously strong closed low is likely to drop southward from the Pacific Northwest and then sweep eastward through Arizona. Cluster analysis indicates strong agreement between the ensemble suites with a dominant cluster showing light precipitation confined mainly to the higher terrain north and east of Phoenix. Grand ensemble points to roughly a 40 percent chance of measurable precipitation in the Valley, though the greater impact will be the breezy/windy conditions preceding the system Tuesday and sharply cooler conditions Wednesday. High temperatures in the Phoenix area may only reach the lower to mid 60s, though the trend continues to be colder. Model guidance also indicates a strong signal for lower snow levels, though an unfavorable storm track and limited moisture will likely yield only minor accumulations in the higher terrain of Gila County. A warming and drying trend is then expected in the wake of this system Thursday and Friday. && .AVIATION...Updated at 0000Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Light westerly winds currently will switch to easterly around 04-05z and remain easterly through the rest of the period. A northeasterly gradient is expected to develop overnight and continue into Saturday morning before weakening Saturday afternoon. This will result in an increase in low-level winds, however LLWS is expected to remain mostly between 25-30 kts, below the threshold of 30 kts for mention in TAF. As the nocturnal inversion weakens by mid to late morning, some of the stronger winds above the surface will mix down to create gusts of ~20 kts. Winds will weaken by Saturday afternoon. Skies will remain mostly clear. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns expected through the period. Aside from winds becoming westerly tonight at KIPL, a northerly component is favored. KBLH will experience winds of 7-10 kts and KIPL will experience winds aob 5 kts. Skies will remain mostly clear. && .FIRE WEATHER... Sunday through Thursday: Strong high pressure will persist early in the period with no measurable precipitation and above normal temperatures prevailing through at least Monday. A weather system is then likely to pass through the region next Tuesday and Wednesday, but overall chances for wetting rains look to be less than 30% and mainly over the Arizona high terrain. Winds are likely to be the main impact with the system with locally windy conditions on Tuesday and possibly Wednesday. Much cooler temperatures are also expected by mid next week. Humidity levels will remain quite low for much of the period with Min RHs ranging between 7-15% through Monday before rising to 20-30% by Wednesday. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ Visit us on Facebook, Twitter, and at DISCUSSION...Hirsch AVIATION...Lojero/18 FIRE WEATHER...Kuhlman
Area Forecast Discussion
National Weather Service Pueblo CO
329 PM MST Fri Feb 11 2022 .SHORT TERM...(This evening through Saturday) Issued at 329 PM MST Fri Feb 11 2022 Key Messages: 1) Winter Wx Advisory Eastern Mountains and I-25 corridor this evening, with brief snowfall rates of 1-2 inches per/hr producing low visibility. 2) On average, total accumulations along I-25 will run from 1-3 inches, while eastern mountains and higher terrain west of the Interstate see 3-6 inches. Upper wave diving southward through the Rockies this afternoon, with heavy banded snow dropping through the Denver metro as of 22z. Mesoscale models and radar trends are in good agreement for this evening, bringing at lighter snow to the Pikes Peak region and portions of the plains north of the Arkansas River before 5 pm, then heavier snow band setting up over El Paso County beginning 5-6 pm, before shifting slowing southward toward the NM border through the evening. Heaviest snow will likely occur in the 5 pm-10 pm range at most locations, and judging from obs in the Denver area, a few brief periods of 1-2 inch per/hr rates and visibility below 1/2sm are likely along and west of I-25 this evening. Snow ends from north to south fairly quickly after midnight, and should be out of the region by sunrise on Sat morning. Made just a few small changes to previously forecast storm total accumulations for the event, nudging snow amounts and qpf upward slightly around Colorado Springs and Pueblo, where HRRR shows heavier band setting up this evening. Mainly minor blowing/drifting expected as lower elevation winds stay in the 10-20 kt range, mountains a little stronger with slightly more areas of blowing snow over higher exposed peaks/ridges. On Saturday, clearing skies and generally light winds in the wake of the upper wave, with temperatures staying slightly cooler than seasonal averages at most locations. Did trim a few degf from maxes along the I-25 corridor to account for expected snow cover, though readings should still be warm enough to melt a good deal of snow, at least at lower elevations. .LONG TERM...(Saturday night through Friday) Issued at 329 PM MST Fri Feb 11 2022 ...A warming trend into the weekend with snow and colder temperatures for the middle of next week... Saturday night-Sunday...Moderating north to northwest flow aloft remains progged across the region into the weekend. This will bring dry conditions and warmer temperatures to the area, with highs on Sunday expected to be in the 50s to lower 60s across the plains, with temperatures mainly in the 30s and 40s across the higher terrain. Sunday night-Tuesday...Flow aloft looks to become more westerly across the region into early next week, as models continue to indicate eastern Pacific energy moving onshore across the Pacific Northwest on Monday, which then continues to translate across the Intermountain West through the day on Tuesday. This pattern will again keep dry, warm and occasionally breezy weather in place across the region through the day on Tuesday. Tuesday night-Friday...While operational models do agree on the eastern Pacific energy moving across the Intermountain West on Tuesday, there remains a lot of variability in the timing, location and strength of this system as it moves across the Rockies in the Tuesday night through Thursday night timeframe. Most of the ensemble mean data suggests the main portion of this system digging south into southern Arizona before lifting out across the southern Rockies, however, there is some support to secondary energy also digging across the northern and central Rockies through this timeframe, leading to a variety of possible outcomes across south central and southeast Colorado. At any rate, timing of the greatest impacts of this system eventually moving across the region seems to be later Wednesday morning and afternoon, with the most widespread snowfall Wednesday night before slowly tapering off through the day on Thursday. Total snow accumulations through this timeframe will remain in flux until the track of this system becomes more defined, however the greatest amounts look to favor areas over and near the eastern mts. After very warm temperatures on Tuesday, highs on Wednesday and Thursday look to fall below seasonal levels, with a slow warming and drying trend expected across the region on Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 329 PM MST Fri Feb 11 2022 At KCOS and KPUB, expect a period of IFR vis from roughly 00z-07z as main band of snow drops south through the area. Current thinking is still 1-3 inches of accumulation possible at both terminals. N-NE winds at 10-20 kts will slowly diminish through the evening. Conditions improve back to VFR after 07z as snow ends and ceilings rise, with VFR through the day on Sat. At KALS, prevailing conditions will be VFR overnight, but with a low risk of a -shsn and brief MVFR vis 02z-06z as a weak weather system moves through the area. Will carry vcsh for now, may need a brief tempo group for showers this evening, though will monitor radar trends before adding anything. On Sat, VFR. && .PUB WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 11 PM MST this evening for COZ083- 085-086. Winter Weather Advisory until 11 PM MST this evening for COZ081- 082-084. Winter Weather Advisory from 6 PM this evening to 2 AM MST Saturday for COZ074-075-087-088. Winter Weather Advisory until 2 AM MST Saturday for COZ079-080. && $$ SHORT TERM...PETERSEN LONG TERM...MW AVIATION...PETERSEN