Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/24/22

Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1148 PM EDT Wed Mar 23 2022 .AVIATION... Showers will persist over KMBS into the overnight, but end elsewhere a mid level dry slot holds over the area. Occluded frontal boundary will shift north and bring a transition from easterly to southwesterly flow will some gusts to 20 knots or more. MVFR ceilings should be the rule into Thursday with KMBS being the exception with IFR/LIFR at least overnight into the morning Thursday. For DTW...Easterly flow will veer to southwest around 06z with the passage of a surface front. Ceilings should remain aob 5kft for a majority of the forecast period (although periods of higher cigs may occur at times). .DTW THRESHOLD PROBABILITIES... * High for ceiling at or below 5000 ft overnight into Thursday. && .PREV DISCUSSION... Issued at 336 PM EDT Wed Mar 23 2022 DISCUSSION... Redevelopment of widely scattered to numerous showers is now underway across northern Ohio given increasing upper-level divergence from left exit jet support along with support from a potent upper-level wave that will move across the Ohio Valley and will clip southern Michigan. This activity will continue to fill in across SE MI through the remainder of the afternoon and evening as a surface low and occluded front gradually starts to pull north across Michigan leading into the evening hours. Embedded elevated thunderstorms will be possible with all activity given the established stronger mid- level lapse rates between 6.5 to 7.5 C/km and weak to modest MUCAPE values ranging between 100 - 500 J/kg. The main severe weather threat with stronger convection will be hail to or just above an inch, generally confined to or south of I96 where the better instability resides. The cooler easterly flow continues to hold the warm sector south of the state line, which is very apparent with temperatures in the upper 40s across southern Monroe county, but nearing 70 degrees at Toledo -- A 20 degree spread over 10 miles. The RAP mesoscale analysis does suggest some surface based instability poking into portions of southwestern Monroe into Lenawee county into the evening hours. This could bring the possibility to see an isolated damaging wind gusts with any stronger convective development. An isolated tornado cannot also totally be ruled out along or south of this boundary given the more favorable low level helicity and low level lapse rates, but again this is highly dependent on the intrusion of the warm sector -- Contrary to the RAP cycles, the latest HRRR holds all surface instability south of the state line, with instability waning as the front finally pushes north into Michigan. Better coverage of rain showers and thunderstorms will decrease from 01Z - 05Z from south to north as the boundary settles across central Michigan and better jet support exits east. As the occluded system gradually travels northeast through the day on Thursday, the better rain chances will develop along this boundary where the better theta- e gradient resides, favoring precipitation chances along the Tri- Cities into the northern Thumb through Thursday morning. Drizzle or light rain showers will be possible for locations south of this boundary through the morning hours, with decreasing odds for PoPs towards the state line. Rain chances and coverage will then again increase from north to south through Thursday afternoon and evening as trough axis starts to shift east along with return flow from the departing low drawing a weak cold front across the state. H850 temperature will drop below freezing with enhanced caa after 18Z on Thursday, and will support a possible rain/snow mix or changeover to melting snowflakes across the Tri-Cities into northern Thumb for lingering precipitation leading into Friday morning. No snow accumulation is expected. A disorganized thermal trough will hold over the Midwest and Great Lakes and will be reinforced as a strong wave travels south across the Plains into the Midwest through Friday. There will be a lack of jet or frontal support on Friday and into the first half of the weekend as a series of mid-level waves either glances the southern Great Lakes or quickly moves over the area. Any precipitation observed on Saturday will likely fall as snow given the ongoing caa with h850 temperatures to -4C and overnight lows rebounding from near freezing. Below normal temperatures will accompany this enhanced thermal trough this weekend, leading into early next week. Highs in the lower 40s on Saturday drop down into 20s early Sunday morning, with the coldest temperatures expected Sunday as highs may struggle to break the freezing mark. A Canadian high pressure system with very dry air will Sunday into Tuesday, bringing little chances for precipitation. Will need to monitor any chances for lake effect snow across Lake Huron early next week as the latest ECMWF run drops h850 temperatures down to -20C by Monday morning. MARINE... A weakening low pressure system will gradually lift across the region tonight. A slow decline in both wind speed and gust magnitude of prevailing easterly flow will occur through this time. Strongest winds going forward into the evening hours will exist across northern portions of lake Huron, where gusts to gales remain possible. Elsewhere, conditions ease sufficiently to allow for expiration of ongoing warning headlines. A low potential for thunderstorms exists through the evening, mainly across lake St Clair and Lake Erie. Modest winds from a southwest direction will emerge in the wake of this system for Thursday. Winds shift to westerly and remain generally light through Thursday night as a cold front tracks across the area. Westerly winds prevail through the end of the week. HYDROLOGY... Widely scattered to numerous rain showers with embedded thunderstorms will push from south to north across SE MI through the evening hours. Any development of stronger storms will be capable of producing a quick half inch to an inch of accumulation. Repeated rounds of shower and thunderstorms will be capable of producing localized higher amounts of accumulation totaling 1.5 to 2 inches. The better probability of these higher localized totals will reside south of I-69, where the better instability and thus stronger thunderstorm chances reside. The better precipitation coverage will diminish from south to north late tonight into Thursday morning. Additional drizzle to light rain chances to then hold on across the Tri-Cities to northern Thumb overnight, before increasing again across the rest of Southeast Michigan later in the day on Thursday. Additional rainfall totals of a tenth of an inch, up to around a quarter of an inch, will be possible centered Thursday morning into Friday morning. Given the prior precipitation, some rises to area rivers and streams are expected. Ponding of water on roadways and low-lying areas are also expected with thunderstorm activity. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Small Craft Advisory until 4 AM EDT Thursday for LHZ421-441>443. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....99 DISCUSSION...AM MARINE.......MR HYDROLOGY....AM You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Gray ME
1109 PM EDT Wed Mar 23 2022 .SYNOPSIS... A slow moving storm complex over the Ohio Valley will drift eastward and affect the region for the next couple of days. Expect precipitation to start as snow and sleet before transitioning to rain at lower elevations, but remaining a wintry mixture across the north and mountains. Unsettled weather will continue over the weekend with a mix of rain and snow showers possible. Notably cooler weather expected into early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 11pm Update...Continued some tweaks to temps and sky cover. As expected, warmer temps in the 40s continue across SW NH where clouds have been prevalent since before sunset. Anywhere to the north and east has cooled rapidly into the mid to lower 30s. With dewpoints in the lower 20s and even upper teens, temps should continue to lower across the Midcoast and ME capitol region. It has been difficult finding model guidance to support this temp gradient, but some HREF guidance blended in across the cooler locations has been helpful. Temp falls should balance out over the next few hours as thicker mid clouds advance NE. With these cool temps in place, have brought the mention of some light snow along the coast during precip onset before temps warm into the day Thursday. 650pm Update...Just a few changes to sky con and temps at this hour. Much of the area is still quite warm after a mostly sunny day. Some of the temperature tweaks were with this fact in mind. Brought in latest obs, and made sure of a faster cooling rate to the north and east where much of the area is cloud free or passing cirrus. To the SW, HRRR does a good job at keeping these areas a bit warmer longer as clouds help insulate against radiation loss into the early evening hours. Previous Discussion... Hybrid Miller-B system moving in from the W tonight with weakeningwave in SW 500 MB flow tracking into New England from the SE. initially will see decent WAA despite the dynamics weakening as they system tracks toward ups. So look fro precip to begin tonight, moving in from SW to NE mainly after midnight, although around them in SW NH. Tricky call on initial p-types in the S late tonight, with temps aloft borderline, as will be boundary lyr temps in some areas inland, especially those areas from around the NH lakes region into the ME lakes region. For this reason, issued an advisory here late tonight into Thu morning, because some areas are likely to see a short period of FZRA, probably around the morning commute with temps 30-32. Otherwise forecast thinking not very different from previous forecast, with a brief bout SN/PL expected at the start in many areas in the south, but with temps above freezing, these quickly change to rain. Interior sections will hang onto SN/PL into Thu morning. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... The weakening first wave will limit sfc flow a bit thu morning, until the second wave develops further to our SW, and this will allow E-SE flow to pick up, and should scour out any of the near freezing near the sfc E of the mtns, which will change everything to rain. In the foothills, shallower cold layer will be pushed above marine lyr, but will hold below warm layer aloft, so looking at elevations in the 1-3K foot range to stay as FZRA or PL longest in these areas, and it is here where perhaps 0.25-0.3" of ice may be possible, especially in the Sunapees and the lower elevation portions of the Whites. further N and E, toward Rangeley and Jackman, should hold onto snow for much of the day Thu, which will eventually mix with sleet or rain /or perhaps a little FZRA as well. Here`s advisories are issued for 3-5" of snow. Precip will lighten up and begin intermittent or drizzly in the afternoon before another round of steadier precip moves in thu evening. Highs range from the low 30s in the mtns, with the exception of SE downslope areas in the Whites which could reach near 40. in the foothills and coastal plain, look for highs of 35-40. The second round of precip that moves through Thu evening will be quicker to get in and out, and will be mainly rain in all but the far NE zones, which will likely stay as a mix of SN/PL. Could see a few sheltered areas stay FZRA as well, otherwise all precip winds down during the pre-dawn, and could see it end as a brief period of snow with no accums to speak of. Lows will be in the upper 20s N to the mid 30s S. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Warm/occluded front will be lifting into the area Friday morning as a secondary surface low develops over New England. The track/timing of the surface low will greatly influence the extent of the warm air advection, which right now looks to push to the foothills before the winds turn and colder air returns, resulting in a large temperature range across the area with highs near 60 in S NH and mid 30s in the mountains. Will continue to see precipitation with a mix in the higher terrain through the day, though some dry slotting is possible on the backside of the low with lessening Pops during the day. The larger pattern continues to show an upper level low/trough that will pivot over the region for most of the long- term (-NAO phase). This will favor unsettled conditions through the weekend with all rain in southern areas during the day, however the thermal profiles favor a transition/mix of snow both Saturday and Sunday nights for most areas. The higher terrain will have the better chances to see snow with light accumulations possible. The source region is limited in moisture so precipitation amounts are expected to be light despite the long drawn-out nature of the event. Cold air advection kicks in behind a strong cold front on Monday, favoring strong mixing and breezy conditions. The colder airmass will linger into Tuesday with below normal temperatures. The longwave trough is projected the deamplify mid to late week allowing temperatures to gradually rebound. Overall no significant precipitation events expected. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short Term...VFR this evening becomes MVFR after midnight, and IFR or lower by Thu morning, with PL/FZRA at KLEB/KHIE/KCON/KAUG. Could see a short period of PL at KMHT around daybreak. IFR will persist through the day Thu into into Thu night. May see some improvement toward daybreak, but may be more likely Fri morning. Long Term...Unsettled weather in the long term with a series of weak surface lows and frontal boundary moving through the region. Periods of MVFR/localized IFR conditions in scattered rain and snow showers likely. && .MARINE... Short Term...Winds seas begin to pick pick up late tonight into Thu with SCA expected through Thu night. Long Term...Series of surface lows and frontal boundaries will favor shifting winds over coastal waters in the long term. The fluctuations will favor some light to moderate chop most days. Winds speeds are projected to strengthen Monday behind a notable cold front with strong small craft or possible gale conditions. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...Winter Weather Advisory from 2 AM to 2 PM EDT Thursday for MEZ012-013-018>020-033. Winter Weather Advisory from 6 AM Thursday to 7 AM EDT Friday for MEZ007>009. NH...Winter Weather Advisory from 2 AM to 2 PM EDT Thursday for NHZ006>011-015. Winter Weather Advisory from 2 AM Thursday to 5 AM EDT Friday for NHZ001>005. MARINE...Small Craft Advisory from 6 AM Thursday to 8 AM EDT Friday for ANZ150>154. && $$ SYNOPSIS...Jamison NEAR TERM...Cempa/Cornwell SHORT TERM...Cempa LONG TERM...Jamison AVIATION... MARINE...
Area Forecast Discussion
National Weather Service Lubbock TX
613 PM CDT Wed Mar 23 2022 .AVIATION... Virga showers are beginning to come to an end at the terminals and will be clear of the terminals by 01Z. Until then continue to expect winds to be sustained around 20-25 knots with gusts to 40 knots. Winds will decrease by late evening and remain light through the night. Expect VFR CIGs and VIS through this TAF cycle. && .PREV DISCUSSION... /issued 155 PM CDT Wed Mar 23 2022/ SHORT TERM... 18Z upper air analysis reveals a compact vorticity lobe rotating southward along the upstream periphery of a mid/upper-level cyclone centered over the middle Mississippi River Valley, with the vorticity lobe nosing its way into the northern TX PH. A secondary yet lesser-defined shortwave perturbation was digging into northern Chihuahua and the Big Bend region. At the surface, northwesterly winds expand across the entire southern and central Great Plains region, with a weak/diffuse, inverted, east-west oriented surface trough located across far southwestern Kansas, the OK PH, and far northern TX PH. The CWA remains far removed otherwise from any viable surface boundary and/or front, as the dominant surface cyclone is rotating across the Upper Midwest this afternoon. The approach of the mid-level vorticity lobe has resulted in an increase in moist, isentropic ascent throughout a shallow theta layer this afternoon, evident by a field of small, turret-like cumulus rooted above a dry and well-mixed sub-cloud layer with near-superadiabatic lapse rates between the surface-to-3-km as per modified 12Z AMA RAOB and RAP soundings. While the sub-cloud layer is very dry, i.e. T/Td spreads of nearly 40 deg F at the surface (classic Inverted-V thermodynamic profiles), a very low chance for sprinkles cannot be ruled out in addition to gusty, erratic winds up to 50 mph owing to the fast cellular movement governed by advection as the mid-level jet streak near 50 kt moves overhead. The orientation of the aforementioned Skew-T profiles will facilitate efficient downward momentum transport for a) blustery, prevailing NWLY winds, and b) enhancing the potential for a dry-microburst or two beneath any convective shower. Convective showers will quickly wane in spatial coverage towards evening given the loss of insolation, along with prevailing winds diminishing altogether as the pressure gradient relaxes as the mid-level vorticity lobe rounds the base of the trough and ejects eastward. Another cold night is ahead as the combination of a clear sky and light winds enhances radiative cooling effects, with lows bottoming out in the middle-upper 20s and lower 30s across the Caprock and Rolling Plains, respectively. Temperatures may be a few degrees colder, as low as the upper teens, in areas affected by terrain- induced drainages. Northwesterly flow aloft will persist tomorrow as the mid/upper-level trough axis moves over the Deep South, though the geopotential height gradient will begin to slacken with NWLY surface winds around 10 kt less than today. With the amplifying mid/upper-level ridging to the west nearing the CWA, the gradual rise in geopotential heights and a well-mixed boundary-layer through ~700 mb will result in temperatures climbing into the upper 60s and lower 70s area-wide beneath a clear sky. Sincavage LONG TERM... A sharp upper level trough currently over the central CONUS will finally begin lose influence over the region on Friday. An upper ridge behind this system over the western CONUS will slowly move eastward through the weekend. This will send temperatures well above seasonal averages from Friday through at least the first half of next week. With a continued lack of rainfall through the time period, fire weather concerns will undoubtedly increase yet again. Temperatures look to soar to values on the order of 15-20 degrees above seasonal averages with strong enough winds for at least elevated fire weather concerns. Late in the weekend, an upper level trough will move onshore on the west coast. However, it remains unclear on how this trough will progress as it moves across the Intermountain West early next week. Surface lee troughing will develop late weekend as a result of this approaching trough which will increase the surface winds into breezy category. FIRE WEATHER... Elevated to possibly critical fire weather conditions are expected to develop tomorrow afternoon across the Caprock and Rolling Plains. The combination of warm temperatures ranging from the upper 60s across the extreme southern Texas Panhandle into the lower 70s across the South and Rolling Plains; breezy, northwesterly winds at around 15 mph at the 20 foot level, and minimum relative humidity values between 8-12 percent will facilitate the potential for a few hours of Red Flag conditions. However, spatiotemporal limitations have precluded issuance of a Fire Weather Watch at this time. Winds will diminish entirely after sunset Thursday with RH recovery between 35-50 percent area-wide. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 51/99/99
Area Forecast Discussion
National Weather Service Marquette MI
638 PM EDT Wed Mar 23 2022 .SHORT TERM...(Through this evening) Issued at 323 PM EDT WED MAR 23 2022 Ongoing event courtesy of an approaching low has proved to be highly impactful and will continue to be so through the remainder of this afternoon into early this evening. For locations from a line somewhere near Crystal Falls/Iron River to Gwinn and Marquette westward, SN has become the dominant precip type. It`s expected to remain primarily SN through this forecast period, with either a wintry mix or rain for locations eastward where slightly warmer air aloft resides. Latest RAP 850mb analysis is somewhat in line with what`s being observed across the U.P., with those sub-zero Celsius temps west of Munising to Menominee. This is forecast to not change dramatically through the next several hours. Additionally, local effects will be in play as a more Nrly component gets added to the wind, allowing for a LS influence to become increasingly likely, notably in the upslope, higher terrain areas of Marquette County into portions of the Keweenaw Peninsula. But, with the synoptically-driven precip rotating along a SE to NW axis, following the 850-700mb wind regime, this won`t necessarily lead to significant impacts beyond what`s already covered within the remaining time of the warning; more like localized periods of enhanced precip. Temps will hover generally where they`re at through the remainder of the daylight hours. As for additional impacts to the ongoing power outage situation, with ice and/or wet, dense snow weighing down trees, branches, and power lines, it won`t take much wind to cause additional issues. Folks should therefore be aware of and prepared for potential power-related issues in the east and along the Lake Superior shoreline, especially as that Nrly component at the surface commences, for those who have thus far remained to have power. .LONG TERM...(Tonight through Wednesday) Issued at 344 PM EDT WED MAR 23 2022 The nearly-stacked 850-500 mb deep trough over the central continental United States will shift northeastwards into Lower Michigan this evening. Precipitation chances continue into the overnight hours tonight as easterly flow maintains a deep moisture profile into the Upper Great Lakes. Wind gusts near 30-40 mph are expected into late this evening near Lake Michigan. These gusts combined with the quarter of an inch to half of an inch of freezing rain prompted an extension of the Winter Weather Advisory until 06z Thursday. As a shortwave ejects southward out of the primary closed mid and low levels shifting northeastward, the winds aloft back northeasterly late tonight across the U.P. Forecast sounding analysis show most p-types shifting to snow with some slight chances for sleet with this colder changeover by early Thursday morning. A high amplitude, fast moving ridge extending north from high pressure traversing through the Upper Mississippi River valley region will bring an end to the precip chances by Thursday evening across Upper Michigan. A band of fgen supported precip is expected Friday out ahead of an incoming colder Clipper. This will spread some light snowfall from west to east Friday morning and through the evening. Gusty northwesterly winds then begin to increase behind the low in the late afternoon/early evening, but really increase in speed Friday night. Communities along the Keweenaw and generally from Marquette eastward towards Luce County could experience northwesterly gusts from 30-40 mph Friday night and early Saturday associated with the cold air advection. Lake enhanced showers are favored in the northwest wind belts for later Friday night and Saturday morning time period, then tapering Saturday afternoon. Continued updates to PoPs away from the national blend were made with this afternoon`s forecast for this time period. At this time, a few inches of measurable snowfall is reasonable in the favored NW wind belts from the earlier band and trailing lake effect showers. A seasonably-colder airmass sets up behind the Clipper for later this weekend. Single digit temperatures are becoming more likely Saturday night and below zero Sunday night, with daytime highs about ten to fifteen degrees below normal on Sunday. The eastern U.P. could see some additional lake effect showers in the north- northwesterly wind belts into Sunday as well. Drier weather and temperatures warming closer to normal are supported to start next week as a synoptic ridge over the western continental US moves into the central US early next week. The WPC Ensemble Cluster tool begins to show widely diverging solutions for the middle of next week as a general mean trough sets up over central CONUS. There is wide solutions on the depth, placement and type of trough though. The end result is fairly low confidence in the resultant impacts for the Upper Michigan for next Tuesday and Wednesday and something to keep an eye on. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 638 PM EDT WED MAR 23 2022 LIFR/VLIFR conditions will persist at the terminals tonight. Conditions will improve slowly on Thu at all sites. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 344 PM EDT WED MAR 23 2022 East gales up to 40 knots across the eastern lake this afternoon shift northeast this evening with continued northeast gales in the western lake. Northeast winds 20 to 30 knots tonight diminish below 20 knots Thursday morning and remain weak through Friday morning. Northwest winds of 20 to 25 kts spread across the lake Friday evening and strengthen to 40 kt gales Friday night, mainly across central and eastern portions of the lake. Northwest gales to 35 knots continue across the eastern lake through Saturday afternoon. Northwest winds 25-33 knots in the eastern lake decrease below 20 knots Sunday evening. Patchy heavy freezing spray is possible Friday night into Saturday morning and then becoming more widespread in the eastern part of the late Saturday and through Sunday morning. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 8 PM EDT this evening for MIZ006- 007-085. Winter Storm Warning until 8 PM EDT /7 PM CDT/ this evening for MIZ001>005-009>011-084. Winter Weather Advisory until 2 AM EDT /1 AM CDT/ Thursday for MIZ012>014. Lake Superior... Gale Warning until 8 PM EDT /7 PM CDT/ this evening for LSZ162- 263. Lake Michigan... None. && $$ SHORT TERM...lg LONG TERM...NLy AVIATION...07 MARINE...NLy
National Weather Service Morristown TN
807 PM EDT Wed Mar 23 2022 .UPDATE... EVENING UPDATE. && .DISCUSSION... The Wind Advisory has been allowed to expire as wind gusts have dropped below advisory levels, and will continue to fall over the next few hours. Showers have ended in our area, and PoPs will be cut back, but a low to slight chance will be kept in NE sections as the HRRR hints at some redevelopment in that area before midnight. DGS && .AVIATION... 00Z TAF DISCUSSION. VFR conditions will continue through the period for all sites. Gusty winds will continue at the TAF sites for a few more hours. Gusts should drop off at all sites by midnight, with winds remaining at 7-10 kt through the night. Tomorrow, winds will increase again in the afternoon, with gusts of 20-25 kt expected. DGS && .PREV DISCUSSION... /ISSUED 335 PM EDT Wed Mar 23 2022/ SHORT TERM...(Today through Tomorrow) Key Messages: 1. Isolated showers and thunderstorms are possible this afternoon. Some of these storms could be strong. Discussion: Currently isolated showers and thunderstorms are moving northeast across Tennessee into Kentucky and Virginia. Some of the stronger storms have had hail, and gusty winds, and some broad rotation associated with them. Based on mesoanalysis and CAMs the best environment for storms in east TN is quickly dwindling as the jet is weakening and moving off to the north and east. While the low level shear has been very strong it`s mostly been unidirectional which isn`t allowing most of these storms to maintain and mature. A slightly better environment exists across West Virginia into Virginia where diurnal heating has been going on for longer... And as some of these storms move into this better environment they could possibly restrengthen, but most likely this will occur further into KY/WV. The more widespread weather event today has been the breezy winds being mixed down to the surface. Numerous weather stations across the region are reporting sustained winds of 20-30mph and gusting over 40mph. The temperatures today have been very warm (some locations reaching over 80) and we`re experiencing very good mixing of the LLJ winds down to the surface. A Wind Advisory is in effect through 8pm EDT when the winds should begin to decouple and the core of the LLJ moves out of the area. Once the isolated storms move out this afternoon, and the LLJ vacates the area weather should quiet down for tonight into tomorrow. We could see a few patchy areas of fog overnight in locations that received rain this afternoon and possibly clear out overnight. Temperatures will be cooler tomorrow without the jet bringing in the warm air from the south. ABM LONG TERM (Friday through Wednesday)... Key Messages: 1. Chilly Friday and through the weekend. Freezing temperatures possible at many locations Saturday night / Sunday morning. 2. Rapid warming starts Tuesday. 3. Storms possible Day 8 (next Thursday). Discussion: In sum, a western U.S. ridge / eastern U.S. trough pattern will hold until Monday, when a deep trough quickly moves into the Rockies. Then the models diverge. So, our troughing for Friday-Saturday will bring our area cool temps and an unsettled pattern that will see a few areas of light precipitation (mostly liquid). The eastern ridge will then move off the east coast, and so while we will continue under cool NW flow for Sunday/Monday, it will be generally dry. Our transition to ridging aloft will net a rapid warm-up Tuesday, with chances for showers north for Tues, and areawide for Wed. This however is where the model divergence comes in. The 12Z GFS is more progressive with the Rockies trough, moving it into the central plains states Wed, while the Canadian and ECMWF dig the trough into northern Mexico and Texas. The winner of these two solutions will determine the timing of the mid-week precip. NBM is going with chance POPs Wednesday with this storm system, but the latest 12Z extended models all agree on holding off precip onset until Thursday, with GFS the earliest (early Thurs morning), the ECMWF Thursday noon, and the Canadian Thurs evening. It is common for Rockies troughs to slow down as model runs progress, so precip onset and conclusion is surely going to need updating. As it stands, the forecast by us and our surrounding offices will carry chance POPS (30 pct) for Wed until more clarity is possible. But I think Wed will end up being a nice day before the possible Thursday storm system. GC && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 43 63 43 59 41 / 0 0 0 0 0 Knoxville McGhee Tyson Airport, TN 44 62 43 56 40 / 10 10 0 10 10 Oak Ridge, TN 43 62 42 56 40 / 10 0 0 10 10 Tri Cities Airport, TN 45 63 40 52 37 / 30 10 0 30 40 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Blacksburg VA
949 PM EDT Wed Mar 23 2022 .SYNOPSIS... Scattered showers and a few thunderstorms look to continue through tonight as a cold front pushes through the region. This is the first of a series of fronts that will deliver cooler air and continued shower chances heading into the start of the weekend. Drier conditions are expected to return with high pressure early next week. && .NEAR TERM /THROUGH THURSDAY/... As of 840 PM EDT Wednesday... A cold front brings additional showers and even a few thunderstorms to the region tonight. Drier conditions Thursday... Overall the current forecast package remains on track with some subtle changes to temperatures, dewpoints, and precipitation coverage heading into the remainder of the evening and overnight period. So far, we have managed to miss severe weather to our west across West Virginia near the cold pool of the occluded low and down to our south across the Carolinas along an old stationary boundary. The wedge remains our friend for now in keeping us fairly stable and limiting any convective concerns. Some signs of erosion in the wedge have been noted off to our west across extreme western Virginia and southeast West Virginia. This trend looks to continue as south to southeasterly flow picks up ahead of an approaching shortwave trough/cold front that looks to push through overnight into early Thursday morning. With that said, the thunderstorm threat looks to remain with us over the next two to three hours. Currently a pool of convection continues to stream north from northern Georgia and western South Carolina. Warnings have been prompted with this area as it surges across the western mountains of North Carolina from Boone, NC south toward Asheville, NC. The latest NAMnest and HRRR guidance continues to enhance this convection as it pushes north along the Blue Ridge. CAPE values in these areas continue to hover between 500-1000 j/kg with bulk effective shear values along a gradient around 65-75 kts. This will be our storm fuel for this evening with damaging winds and the potential for an isolated tornado as the primary threat, especially in areas along the southern extent of the Blue Ridge. For that reason a Tornado Watch is in effect for the southern Blue Ridge from now through midnight. On top of the severe weather concerns comes the risks for localized flooding due to storms training over some of the same areas. Rainfall in these areas has already exceeded one to two inches over the last 24 to 48 hours. Areas outside of the Blue Ridge have seen amounts upwards of a quarter of an inch to three quarters of an inch throughout the last 36 hours. Luckily for us no widespread flooding is likely due to the antecedent dry conditions. All of this is in advance of a cold frontal boundary that will steadily push east from West Virginia and eastern Kentucky tonight. The front will be driven by additional shortwave troughs rotating around a deep upper level trough that encompasses much of the eastern two-thirds of the country. This trough will gradually kick out of the region later in the week, but until then it will be a continuation of front after front until the weekend. As of now our cold front tonight should push into southeast West Virginia, the New River Valley, Mountain Empire, and ALleghany Highlands between now and midnight Thursday. From there the front will gradually inch east toward the Roanoke Valley, North Carolina foothills, and Piedmont late Thursday morning into Thursday afternoon. Precipitation should decrease in coverage (and intensity) from west to east later tonight through Thursday mid- morning as the front traverses the area. A lull in the wet weather looks to occur Thursday afternoon into Friday. The exception of this will be over the mountains where additional showers are likely as another piece of shortwave energy rolls through. Overnight lows tonight will fall into the 40s over the mountains to the 50s further east into the Piedmont in advance of the front. We rebound with a little more sunshine in the wake of our front Thursday. South to southwesterly flow gets temperatures back into the low to mid 60s over the mountains to upper 60s and low 70s further east. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY NIGHT/... As of 200 PM EDT Wednesday... Light showers mostly in the mountains, and some snow this weekend for Southeast WV... Behind a cold front on Thursday night, an upper trough and cooler air will move in to the area. This will allow for some stronger westerly winds and a bit of upslope rain Friday afternoon and evening. A much deeper upper trough and reinforcing cold front will arrive overnight Friday into Saturday morning. Chances for rain will spread to the Blue Ridge throughout the day Saturday, as this upper trough will pass much closer to us than the Thurs/Fri trough. As the the coldest air of the week so far is pulled into the CWA, below freezing temperatures will be found in mountain areas. This will lead to snow restricted mostly to Western Greenbrier County, WV overnight Saturday into Sunday. Localized accumulations of 1-2" are possible, but the vast majority of folks that see any flakes will get a dusting up to an inch. Temperatures during this period will be around normal during the daytime, but after the cold front Friday night, temperatures overnight will plummet to near freezing in the east, and solidly below freezing west of the Blue Ridge. Little recovery in warmth is expected Sunday as we remain in northwest flow and high pressure is advected into the area from the northwest. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... As of 130 PM EDT Wednesday... Broad upper level northwest flow follows behind the weekend system, as high pressure begins to move into the Mid Atlantic around the beginning of next week, before transitioning to a more westerly direction. Temperatures will begin to warm up compared to the cooler weekend temperatures. Dry conditions are expected through Monday, before the arrival of a warm front moving northward towards the area. This front will likely bring another round of mid-week precipitation for Tuesday into Wednesday. However, there is not much agreement between models on the timing and extent of the precipitation. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... As of 0950 PM EDT Wednesday... ...Sub VFR conditions continue overnight into Thursday morning as showers and thunderstorms push through... Shower and thunderstorm activity continues to slowly push through the area this evening as a cold front pushes in from the west. The bulk of the activity remains from KROA/KLYH south to KBCB/KMTV and KUKF. This area continues to see a mix of MVFR and IFR cigs/vsbys as heavier showers push through. Some thunderstorm activity has also been mixed in with a few flickers of lightning at both KBCB, KTNB, KROA, and KLYH. The thunderstorm threat has decreased at most of the TAF locations with the exception of KLYH where a TEMPO has been left in for the next 3 hours as convection continues to push through. Elsewhere VFR conditions remain to the west at both KBLF and KLWB as well as to the east toward KDAN. These areas will also see shower activity overnight into Thursday morning as the front pushes through. Any shower or thunderstorm activity looks to quickly come to an end between 05z/1am and 07z/3am Thursday morning. Despite the precipitation ending and the front gradually pushing through, low cigs/vsbys will remain at most of the terminals. MVFR to IFR flight categories are expected through at least 12z/8am Thursday morning as our cold front is slow to move east. It`s not until after 16-18z/12-2pm that most locations return back to VFR. Winds will remain out of the south and southwest tonight at 5 to 15 kts with gusts upwards of 20 to 30 kts along the higher ridges along and west of the Blue Ridge Parkway. Winds will switch toward more of a westerly direction behind the front Thursday morning into Thursday afternoon. Speeds once again will be between 5 to 15 kts with gusts upwards of 15 to 25 kts along the ridges by Thursday afternoon. Extended Aviation Discussion... VFR conditions will remain for most with the exception of the mountains through Friday morning. Sub VFR conditions make a return with our next cold front Friday afternoon into Saturday morning.The front clears the area late Saturday into Sunday as high pressure returns. VFR conditions kickoff the start of the new workweek. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...ET NEAR TERM...DB/ET SHORT TERM...VFJ LONG TERM...AS AVIATION...ET
Area Forecast Discussion
National Weather Service Topeka KS
546 PM CDT Wed Mar 23 2022 ...AVIATION UPDATE... .DISCUSSION... Issued at 304 PM CDT Wed Mar 23 2022 KEY MESSAGES - Rain/snow showers through tonight (no snow accumulations) - Slow warmup through early next week - Precipitation may return by the middle of next week This afternoon, a highly amplified pattern continues to dominate the CONUS, highlighted by ridging over the Rockies and the Atlantic, and a deep trough from the Southern Plains to the Great Lakes. Beneath the upper trough, a deep SFC cyclone was located over the Upper Midwest, with a broad, and moist, cyclonic flow dominating the region. Within this flow, a few embedded waves are rotating south across the region, each with an enhancement to shower activity. One such wave is moving south out of Nebraska/Iowa this afternoon, and will bring a modest uptick in shower activity across northeast Kansas through tonight as it pivots through the area. Despite temperatures in the upper 30s to low 40s this afternoon, wet-bulb temps are in the low to mid 30s, and forecast thermal profiles suggest temps aloft are plenty cold enough to support a rain/snow mix, or even all snow at times, even with marginal SFC temps. mPING reports across the area support this as well. Snow accumulation is not expected, but a rain/snow mix can be expected through tonight where showers occur. On Thursday, subsidence aloft and drier low-mid level air attempting to work into the area should lead to a gradual clearing of the low clouds from west to east by mid to late afternoon. Although, there may be enough lingering low-level moisture to support scattered afternoon cumulus development in the wake of any morning clearing, which may temper highs just a touch. On Friday, an upper wave will move through the Great Lakes, glancing the Mid-MS Valley region. While significant impacts are not expected, a cold front will move through with gusty winds and cooler temperatures. Because of the glancing nature of the upper wave, the SFC front will lose upper level support and basically get hung up to our west and south over the weekend. With NE Kansas being on the "cooler" side of that boundary, model guidance have trended cooler FRI-SUN in the developing E/SE low-level flow. Aloft, a fairly prominent baroclinic zone looks to setup NW to SE across the Central Plains. Synoptically, NW flow atop a stalled baroclinic zone can be a great setup for convection, especially later in the spring and summer. However, with early spring moisture and instability, it appears the risk of showers or storms should mostly be muted, but the risk isn`t zero. For now, we`ll continue to keep the forecast dry, but something to watch as some model guidance hint at some shower potential Sunday into Monday. At minimum, there may be a little more cloud cover around at times. With time, the baroclinic zone should lift NE into the Upper Midwest as a more prominent west, or southwest, flow aloft develops early next week, favoring strengthening WAA and an increased southerly flow. This should lead to a quicker warmup early next week and the forecast reflects this expectation. Should the SFC front remain to the south, though, temps may end up not as warm early next week. By the middle of next week, significant differences show up in model guidance with the evolution of troughing attempting to redevelop from the Rockies into the central CONUS. Generally speaking, there appears to be decent support for a cold front passage Tuesday or Wednesday with a quick shot of colder air, and possibly another risk of precipitation. Martin && .AVIATION...(For the 00Z TAFS through 00Z Friday) Issued at 546 PM CDT Wed Mar 23 2022 Moisture wrapped around the low pressure system over the Upper Midwest is forecast to keep MVFR CIGS over the terminals and northeast KS until late in the period. CIGS may improve temporarily at MHK, but the latest forecast soundings from the RAP show the lower CIGS moving back in. There is likely to be some -RASN with the radar returns moving south through the area. This should have limited impact at the ground but would likely pose some low level icing concerns. The precip is forecast to fall apart shortly after 06Z tonight. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION...ICT/Martin AVIATION...Wolters