Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/21/24


Area Forecast Discussion
National Weather Service Charleston SC
907 PM EST Wed Nov 20 2024 .SYNOPSIS... A strong cold front will push farther offshore tonight. Canadian high pressure will build across the area Thursday and will remain the primary feature through early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... No major changes were made for the late evening update. Tonight: Satellite and 21/02z mesoanalysis showed the cold front extended from the far eastern Midlands to just west of Lake Moultrie and extending south along the Georgia coast into Northeast Florida. The front is marked by a strong stability gradient and will continue to move rapidly east and offshore. Strong post-frontal cold air advection will follow the front by several hours, but will usher in a slightly modified cP airmass as the night progresses. Lows look to bottom out in the lower 40s well inland to the upper 40s/near 50 at the beaches. Gusty northwest winds will make it feel even cooler by daybreak Thursday with wind chills dropping into the upper 30s/lower 40s. Lake Winds: Impressive and deep mixing profiles will develop on Lake Moultrie overnight as strong post-frontal cold air advection ensues with the passage of the cold front. RAP soundings support as much as 35-40 kt of wind at the top of the mixed layer by midnight supporting winds 20-25 kt with gusts at least to 30 kt, if not a tad higher at times. Winds were slightly with waves over the open lake waters building to 2-3 ft. The combination of increasing winds and building waves will make for dangerous wave action on the lake tonight with the worst conditions occurring over the central and eastern portions of the lake. Boaters are encouraged to remain off the lake. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... A powerful closed upper low will swing through the Great Lakes on Thursday then stall near New England Friday into Saturday. Meanwhile, strong high pressure will expand across the Southeast at the surface. Dry weather and below normal temps expected. Highs will top out in the upper 50s to lower 60s on Thursday, then only reach the mid/upper 50s on Friday. Saturday should be a tad warmer with highs in the lower 60s. Lows both nights could dip into the mid to upper 30s inland, though we expect enough overnight wind to prevent widespread frost development. Lake Winds: Gusty west winds are expected to persist over Lake Moultrie Thursday into Thursday evening during which we have a Lake Wind Advisory in effect. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... Surface high pressure will maintain influence over the local weather Sunday through Tuesday. Not much going on upstairs with relatively zonal flow. Rain-free forecast in place with warming temperatures through the period. Main forecast concern remains the potential for frost late Saturday night/early Sunday morning as ideal radiational cooling conditions allow temperatures to fall to the mid/upper 30s inland of the coast. Frost is possible, mainly over far interior locations. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... 21/00z TAF Discussion: KCHS/KJZI/KSAV: The approaching cold front will clear all terminals by 02z with gusty northwest winds developing with its passage. These gusty winds will persist into the day Thursday. Any lingering low clouds should scour out with FROPA. VFR will prevail for the entire 00Z TAF period. Extended Aviation Outlook: VFR. Gusty west winds are expected Thursday and Friday. && .MARINE... Tonight: Strong post-frontal cold air advection will overspread the waters overnight with the passage of a cold front. Northwest winds will increase to 25 kt with gusts to 30 kt for the waters within 20 NM and 25-30 kt with gusts 35 kt over Georgia offshore waters out 20-60 NM. A Gale Warning remains in effect for the Georgia offshore waters beyond 20 NM with high- end Small Craft Advisories for all nearshore legs, including Charleston Harbor. Gusts could get close to Gale Warning criteria across the nearshore waters, mainly within 10-20 NM, but these conditions look infrequent enough to not to justify an upgrade to a Gale Warning at this time. This will be closely watched this evening and overnight, however. For Charleston Habor, northwest winds will increase to 20-25 kt with gusts to 30 kt and waves building 2-3 ft. Thursday through Monday: Gusty west winds will persist over the coastal waters Thursday through Friday night, maintaining the ongoing Small Craft Advisories. For the Charleston Harbor, gusts to 25 knots are expected Thursday through Friday. Improvement is expected Saturday with winds and seas remaining below advisory levels through Monday. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...Lake Wind Advisory until 11 PM EST Thursday for SCZ045. MARINE...Small Craft Advisory until 6 PM EST Friday for AMZ330. Small Craft Advisory until 7 AM EST Saturday for AMZ350-352- 354. Gale Warning until 7 AM EST Thursday for AMZ374. && $$
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
743 PM EST Wed Nov 20 2024 .KEY MESSAGES... - Colder temperatures arrive tonight, with snow expected to be seen in the air in most places at times from Thursday into Friday. - Locations most likely to receive impactful snow accumulations are those elevations above 1500 feet, mainly Thursday night. && .UPDATE... Issued at 742 PM EST WED NOV 20 2024 Sfc high pressure nosing into the region in between systems has led to a slackening pressure gradient and some of the deeper valleys decoupling. This has resulted in some of these valley areas to cool off faster than the previous forecast. Following recent rainfall and with the clearing skies and slackening winds, the potential for at least a period of patchy fog later this evening or in the overnight has increased before clouds increase again. Adjustments to hourly visibility, weather, temperature, and dewpoint grids have been made accordingly. && .SHORT TERM...(This evening through Thursday night) Issued at 329 PM EST WED NOV 20 2024 We have a very active short term period with multiple rounds of precipitation and gusty winds at times. We begin the period with a strong cold front crossing the area this afternoon. This has nearly eclipsed most of the region now with just parts of far eastern Kentucky still in the upper 50s to 60s at 2 PM. This front has packed quite a punch this afternoon, with winds gusting up to 42 mph here at JKL and many more open and high elevation locations seeing 35 to 40 mph. Given this did increase through winds closer to the HRRR this afternoon along and ahead of this boundary. However, they will relent through the afternoon. The latest trends in the satellite show that there is decent clearing behind the front across parts of central Kentucky and this will slide into the eastern Kentucky later this afternoon and into the evening. This will lead to mostly clear skies tonight before the next wave of energy approaches by from the northwest bring in low and mid level clouds by early Friday. Overnight lows will fall into the low to mid 30s. Thursday, another lob of energy drops southward with a another cold front. This cold air advection pattern will steepen the low level lapse rates tomorrow afternoon. This will aid in enhancing the snow shower potential tomorrow. These rounds of snow showers will be accompanied by gusty winds at times in the 20 to 25 mph range at times. Also, heavier snow showers could lead to brief reductions in visibilities. There is good agreement in the models for this to be all snow given the wet bulb potential with dewpoints in the mid to upper 20s through the day. The good news is highs in the afternoon will be in the upper 30s for most and therefore should be less impactful for travel given the warm temperatures we have seen of late. Therefore perhaps some grassy and elevated surfaces see a dusting to perhaps a quick half an inch. However, fairly low confidence on seeing much out of this initial round. Thursday night, Another strong undulation in the mid-level slides southward Thursday evening. There will also be some support from a upper level jet streak left exit region giving way to some decent divergence aloft. The surface reflection in the form of a low pressure does ramp down as it heads into the Ohio Valley, but there will still be ample energy for another round of snow to slide into the area. Overall the profiles will support snow through the evening and into the night. However, as we move into the night and overnight the sounding show a warming trend as you advect some warmer air into the area. You also start to loose the better ice in the DGZ based on some of the HREF forecast sounding data toward Friday morning. This will lead to some of this activity starting to mix to more of the rain/snow late Thursday night into early Friday morning for most areas outside of the higher terrain where temperatures will be slower to climb. Right now, based on temperatures at the surface most locations will only see snow accumulations on grassy and elevated surfaces. However, it still looks like locations above 1500 feet would have a decent shot of snow accumulations on more surfaces with highest amounts still mainly above 3000 feet. That said, given this no plans to change or modify the current Winter Weather Advisory. .LONG TERM...(Thursday night through Tuesday) Issued at 328 PM EST WED NOV 20 2024 Active weather expected to continue in the extended portion of the forecast, as a series of low pressure systems move through the region. The latest runs of the GFS, ECMWF, WPC guidance, and GFS Ensembles all have similar solutions, with large and well developed low pressure centered over southwestern New England. This system will be quite large, and will be impacting an area that includes New England, the western Great Lakes, the Ohio Valley, the Mid-Atlantic region, and the central Appalachians. Rain and showers are expected across eastern Kentucky Friday through Saturday, as moisture wrapping around the back side of the eastern low pressure interacts with the terrain of the forecast area. Light snow accumulations will be possible with this activity, especially in the higher terrain along the Virginia border on Friday. Temperatures should warm up enough Friday into Saturday, to allow snow to change over the rain for all but the highest ridges along the Virginia border. The precipitation will linger across far eastern Kentucky through the end of the day on Saturday, before the upper low moves far enough to our east to allow the precip to finally come to and end. A ridge of high pressure will settle over the region over the weekend, and will bring dry and warmer weather back to the area Sunday and Sunday night. After this brief respite, another area of low pressure will barrel through the region late Sunday night and Monday, and will bring multiple rounds of rain to eastern Kentucky the first half of the week. This system will develop over the central Mississippi valley and east central Plains, and will move quickly into the Great Lakes by Monday night. A surface cold front extending southward from this system will be our weather maker through the middle of the week. The latest NBM data suggests that this boundary might get hung up over our area, and will allow precip to linger for a couple of days while the front is in place. Temperatures will be well below normal overall, with several days expected to max out in the 40s and low to mid 50s. Sunday and Monday look to be much warmer, with highs in the upper 50s to lower 60s both days. This will be in response to the persistent southerly flow that is expected to set up across the region to begin the new work. As far as weather hazards go, the only thing we`ll really be watching is whether or not enough snow will fall, and if its will be cold enough, to lead to slick roads on Friday, especially early in the day in our eastern higher terrain counties along the Virginia border. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) ISSUED AT 725 PM EST WED NOV 20 2024 High pressure nosing into the region has led to a decrease in winds and gusts this evening with some deeper valleys having decoupled near and after sunset. Skies have also cleared with VFR observed across the region. In this area of clearing, some valley locations could experience some MVFR to IFR reductions in valley fog, but TAF sites are not expected to be affected. Winds will then ramp up again between 12Z and 15Z from the west in advance of the next round of weather, with gusts of 20-25 KT possible during the last 12 hours of the period. At this time, have some VCSH for KSYM, KSJS, and KJKL after 12Z with even prevailing light rain and light snow toward the end of the period at these 3 sites. MVFR ceilings and/or vis especially within heavier rain and snow showers will affect northern and eastern sections of the area starting after 13Z with KSYM, KSJS, and KJKL most likely to experience these reductions later in the period. At the very end of the period, these may spread to near or west of I-75 and KLOZ and KSME could be affected as well. && .JKL WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory from 7 PM Thursday to 10 AM EST Friday for KYZ087-113-115-117-120. Winter Weather Advisory from 4 PM Thursday to 10 AM EST Friday for KYZ088-118. && $$ UPDATE...JP SHORT TERM...DJ LONG TERM...AR AVIATION...JP
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1002 PM EST Wed Nov 20 2024 .SYNOPSIS... A strong cold front will move across the area tonight. Another reinforcing cold front moves through on Thursday, followed by yet another front on Friday. High pressure then builds in over the weekend and into next week. && .NEAR TERM /OVERNIGHT/... As of 10 PM Wed...Cold front is now racing towards ENC this evening with this front currently stretching from NE to SW across the Triad vicinity and currently moving through Raleigh as of this update. Have several gusts in the 30-40 mph range as this front continues to make its way across NC. Given the fronts current speed, can expect these gusts to reach the western Coastal Plain within the next hour or so and then nearing the coast closer to the midnight to 1AM timeframe before pushing offshore. Expecting a brief period of widespread 30-40 mph NW`rly wind gusts behind this front across the Coastal Plain with slightly higher gusts possible near the coast and OBX. Once the front quickly moves through the area, winds will ease rather quickly as well with gusts falling closer to 15-20 mph about an hour after the front passes through. Otherwise outside of this, current forecast trends hold with scattered showers and maybe a rumble of thunder or two possible through about 1-2 AM across ENC out ahead of the front before it pushes offshore. Prev Disc...Attention turns to strong arctic front which will blast through loudly tonight, as it will be accompanied by a short but strong burst of gusty winds. The front is currently moving through the TN Valley, and will be moving through the NC mtns early this evening, and then quickly across the state through ENC through the late evening hours. There will be sct to numerous showers along and just ahead of the front, but the big story will be the very gusty winds, and have inc winds as a result. Think that most places even inland will gust to 30-40 mph, and on the coast 35-45 mph as it passes through. Have relied heavily on the hourly HRRR for the fropa and associated winds and temps. These winds will be short lived and last a half hour or so at most but the temps will drop sharply in its wake, going from the 60s, then quickly into the 50s and 40s for their eventual lows by morning. && .SHORT TERM /THURSDAY/... As of 3 PM Wed...High temps return to closer to normal and even slightly lower than climo, with readings in the upper 50s to around 60 for most. Blustery conditions with wrly winds of 10-15 gusting to around 20 mph. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 3:20 AM Wednesday... Thursday night - Saturday night...The next front will move through late Thursday afternoon and its CAA will send lows into the low to mid 30s across the coastal plain. Winds will remain strong enough to help minimize the threat for widespread frost/freeze impacts, but it`s not out of the question for some sheltered areas to drop below freezing. Saturday will feel very similar to Thursday with highs struggling to exceed the 50s and breezy winds westerly winds. Sunday - Tuesday...High pressure will develop over the southeastern US and extend up the mid-Atlantic coast. This will support a dry forecast and warming trend with high temperatures climbing from the upper 50s/low 60s on Sunday to the upper 60s/low 70s on Tuesday. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... SHORT TERM /through Thursday/... As of 7 PM Wednesday... - Strong cold front to bring gusty winds, SHRA, and sub-VFR conditions to ENC this evening A wide range of VFR to LIFR conditions are currently over ENC this evening out ahead of a rapidly approaching front. Currently OAJ/EWN are VFR with ISO at LIFR conditions and PGV at MVFR conditions. General trend remains the same with any leftover VFR conditions quickly becoming MVFR and IFR across the region just out ahead of the approaching front with PGV/ISO maintaining MVFR/IFR ceilings/vis over the next few hours. The cold frontal passage will then be the main challenge tonight. Front is forecast to enter into the Coastal Plain around 02-04Z tonight and first impact PGV/ISO between 03-04Z followed by EWN/OAJ between 04-05Z before finally pushing offshore by 06Z. As the front tracks across the area winds will quickly shift from SW to NW and gust to as high as 25 to 30 kt for a brief period of time before gradually easing over the following several hours. In addition to this some cross wind issues mainly at ISO/EWN will be possible as the front tracks across these TAF sites with a strong NW`rly wind. Guidance suggests some heavier showers immediately with the front, and have opted to bring in temporary IFR conditions this evening. A few TSRA cannot be ruled out, but this risk appears low (<20% chance), and we`ll continue to keep TSRA out of the TAFs for now due to the low risk. Behind the front, conditions should quickly become VFR while winds should decrease to around 10 kt by 12z. Some increase in W`rly wind gusts Thursday to 20kt. LONG TERM /Thursday night through Monday/... As of 4 AM Wednesday...Gusty winds will be the main aviation concern through the long term. With multiple fronts forecast to move across the area, westerly winds around 10-15 kt with gusts to 20 kt will persist through Saturday. Winds will weaken to 5-10 kt on Sunday as high pressure begins to extend into the area. && .MARINE... SHORT TERM /through Thu/... As of 3 PM Wed...S to SW winds of 10-15kt expected through early evening. Big story will be strong arctic front that will blast through the waters later this evening through early morning hours. The wind switch will be very dramatic, and increase out of the NW with a 35-40 kt gust(s) as the front passes through. Because the gusts are expected to be tied to the fropa, will not issue a gale warning because of the very brief nature of the winds lasting less than an hour, but instead handle with MWS`s as the front nears the waters, which will be around midnight. SCA`s remain in place for all coastal waters and inland rivers. Have ended the Neuse/Pamlico/Bay rivers a bit earlier, but later shifts will likely have to reissue these as winds come back up late afternoon or early eve Thu with reinforcing fropa. LONG TERM /Thursday night through Monday/... As of 4 AM Wednesday...Additional cold fronts on Thursday and Friday will generate unfavorable marine conditions that will persist through early Sunday morning. Seas will be the highest early Thursday morning (6-7 ft) and late Friday night (6-7 ft) with a slight lull between these times. A slight lull is expected during the afternoon, after which winds will become westerly and return to the same strength. Winds will peak on Friday at 25-30 kt with a few gusts to 35 kt. We continue to carry a strongly worded Small Craft Advisory for the central waters at this time, but a Gale Watch will be kept in mind. Winds and seas will decrease through the day Saturday with all zones expected to be below SCA criteria by early Sunday. && .FIRE WEATHER... As of 3 PM Wednesday...Elevated fire weather conditions are possible Thursday, with min RH values falling to 30-35% inland combined with westerly wind gusts 20 to 25 mph. && .TIDES/COASTAL FLOODING... As of 3 PM Wednesday...An extended period of 20-25kt Werly winds behind a cold front tonight into Saturday may lead to minor soundside flooding concerns for the Outer Banks. Current thinking is these persistent Werly winds should remain just weak enough to limit impacts, but minor water level rises will be possible for soundside NOBX, Hatteras and Ocracoke Islands, and Roanoke Island. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory until midnight EST Saturday night for AMZ131-135-158-230-231. Small Craft Advisory until 8 AM EST Thursday for AMZ136-137. Small Craft Advisory until 3 AM EST Sunday for AMZ150-152-154- 156. && $$ SYNOPSIS...MHX NEAR TERM...TL/RCF SHORT TERM...TL LONG TERM...CQD/OJC AVIATION...RCF/OJC MARINE...TL/OJC FIRE WEATHER...MHX TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
844 PM CST Wed Nov 20 2024 .KEY MESSAGES... - Light snow continues through this evening. Slick travel is possible, especially with gusty winds. - Strongest winds in western MN, gusts as high as 35mph. - Dry weather returns tomorrow, with strongest winds shifting east into western WI. && .UPDATE... Issued at 835 PM CST Wed Nov 20 2024 After a few hours of moderate snow this evening, reports of 1-1.5" of accumulation are common from the Twin Cities metro southward. Any heavier/accumulating snow will continue to wind down across the region, but occasional flurries/freezing drizzle will continue overnight. Travel remains treacherous with very slick roads following this evening`s snow, which seems to have largely melted before refreezing on roadways. Temperatures will remain below freezing tonight, so expect difficult travel to persist into tomorrow morning. Gusty northwest winds continue across western Minnesota with gusts near 40 MPH at times, further complicating travel in this area. && .DISCUSSION... Issued at 254 PM CST Wed Nov 20 2024 Snow totals have generally remained at or below an inch through our first round of snow this morning, with the highest totals further north and west where the Winter Weather Advisory is still in place. It currently is in effect until 6PM, but that may need to be extended depending on how quickly the second round of snow moves southeast. Latest hi-res guidance keeps additional totals right at or below 2 inches for those northwestern counties, and at or below 1 inch for elsewhere. It is expected that well-traveled roadways will largely avoid any accumulations (similar to this morning), but slick conditions may still develop with temperatures dipping below freezing for much of the region already. The main driver of forcing associated with this second push of snow is positive (cyclonic) vorticity advection as the low moves east. These setups can result in sporadic bursts of heavier rates, which is highlighted by the latest suite of models, favoring portions of east-central and southern Minnesota. These high rates combined with strong, gusty winds could lead to reduced visibilities at times. This is important to be aware of given the timing taking place during the evening rush hour. Snow should begin to taper off from north to south around 7 to 8 PM, completely moving out of the area overnight. As the surface low and occlusion aloft weaken, the strongest forcing and winds will move east. As a result, most locations will be entirely dry tomorrow, outside of a few light rain/snow showers across west-central Wisconsin. The main concern will be a return of strong, gusty winds, primarily over western Wisconsin and eastern Minnesota. The latest RAP and HRRR show potential for 35 to 40 mph wind gusts to mix down from 925 hPa. These locations have seen the lowest totals for snowfall so far, and are expected to have little to no blowing snow concerns with these winds. An area of ridging upstream of the upper low will help lead to drier, and consistent conditions through the weekend. Long range ensembles continue to highlight potential for multiple systems moving across the central CONUS next week, however there is quite a bit of spread in timing and location. Members of the GFS ensemble have higher agreement of a low impact snow-maker moving through as early Sunday night, while the EPS favor a more impactful storm moving through towards the end of the week without as much of a sign for an early week system. All that to say, there is still a lot to decipher after our current system departs east, but there is at least a notion that an active pattern is likely across the region. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 518 PM CST Wed Nov 20 2024 We have a few more hours of snow to go with IFR cigs/vis before conditions improve back to MVFR through the overnight. A few sites may briefly pop up into VFR territory overnight, but a return to MVFR is expected by tomorrow morning. Wind wise, a more north-northwesterly direction is expected to take hold overnight with speeds diminishing to around 20kts. Gusts of 25-30kts will return by late morning and last through the end of the period. KMSP...One more heavier band of snow is approaching the northwest metro as of 23z. This should be done by 02z with high end MVFR overnight. As mentioned above, winds will be gusty again tomorrow. /OUTLOOK FOR KMSP/ FRI...Chc MVFR cigs. Wind NW 10-15kts. SAT...Chc MVFR cigs. Wind NW 5-10 kts. SUN...VFR. Wind SE 5-10 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ UPDATE...Dye DISCUSSION...BED AVIATION...Dye
Area Forecast Discussion
National Weather Service Marquette MI
852 PM EST Wed Nov 20 2024 .KEY MESSAGES... - Light wet snow accumulations possible tonight, mainly in the higher terrain west of US-41 and south of the Keweenaw. - Northerly gales 35 to 40 knots with a few gusts to 45 knots possible across Lake Superior. - Widespread 25 to 35 mph northerly winds will be possible across Upper Michigan Thursday. Higher winds to 45 mph will be possible in the Keweenaw Peninsula and near the immediate lakeshores of Marquette and Alger counties. && .UPDATE... Issued at 852 PM EST Wed Nov 20 2024 The forecast remains on track tonight. Light rain showers are spreading westward through the UP tonight, with periods of bright- banding unsurprising given freezing levels only at around 1000ft. Some spots, particularly in the higher terrain, are already seeing snow mix in. Minor adjustments with this forecast update have been to bump up winds slightly over the western half of the UP into early Thursday. We may flirt with Wind Advisory criteria across the Keweenaw and closer to Superior in Marquette county, but with some lingering uncertainty as the highest model guidance closer to 45mph remains an outlier, will hold off on headlines. && .SHORT TERM /THROUGH TONIGHT/... Issued at 407 PM EST Wed Nov 20 2024 Current RAP analysis shows an elongated mid level closed low over MN and WI with a ridge over the Rockies. As a shortwave rotates around the mid level closed low this evening through tonight over MI, a sfc low deepens over the lower Great Lakes. The weakening sfc low phases with the deepening low as it rotates from Lake Huron to eastern Upper MI. Strong q-vector convergence over the east has allowed for showers to expand over the eastern UP as visible on radar imagery and available webcams. Reflectivity returns have periodically lifted over portions of the central Upper MI and the Keweenaw already today, but an antecedent dry airmass highlighted by dewpoint depressions of up to 10-15F has really worked against precip expanding westward. While some isolated rain and snow showers are possible in the west half ahead of 7 PM EST, better chances hold off until later this evening through tonight. At that point, a colder airmass will have moved over the west, aiding in a transition over to snow showers. Minimum temps in the low 30s to low 40s are expected early on tonight as WAA strengthens after midnight. That said, some light wet snow accumulations are possible tonight, mainly west of US-41 and south of the Keweenaw. Highest snow totals up to 1-3 inches are possible in the high terrain of Baraga County. Opted to cover potential hazardous travel conditions overnight with a SPS as a transition over to rain showers by Thursday morning will likely work against any snow accumulations. Otherwise, the strengthening low approaching from the east will result in increasing northwest winds tonight. Gusts are expected to approach 20-30 mph (up to 35 mph in the Keweenaw) by Thursday morning. && .LONG TERM /THURSDAY THROUGH WEDNESDAY/... Issued at 429 PM EST Wed Nov 20 2024 Heading into the late week, a closed 500mb low over the Upper Midwest descends southeast across the Great Lakes into the Eastern Seaboard. By Thursday morning, the attendant surface pressure reflection will have rounded counterclockwise above the Mitten of Michigan and deepened to near 993mb just west of the Straits of Mackinac. Guidance is in good agreement on a period of enhanced northerly flow across Lake Superior following strong pressure rises where gusts 35-40 knots are likely (80-100% chance) Thursday morning into the evening. At the same time, ongoing rain/snow mix will be transitioning to all rain as the low pressure rotates down Lake Michigan Thursday. While northeast flow over Lake Superior typically results in cold air advection and lake effect snow, the wound-up TROWAL sends in low-level temps just above freezing. Rain amounts Thursday will be maximized in the east and central UP where northerly upslope could aid in some locals accumulating over an inch. As the surface low pressure and upper low continue into the eastern seaboard, ridging nudges in from the west into the Upper Great Lakes Friday, filtering in drier air aloft. Some light precip and drizzle will linger Friday with northerly upslope flow. A shortwave dives southeast over Northern Ontario Saturday, sending a shot of colder 850mb temps around -8 to -10C across Lake Superior. Sufficient lake induced instability will be present for lake effect clouds and maybe some light rain/snow showers over the east UP, however, any showers will be fighting a dry surface layer, so little to no accumulation is expected. Active weather continues beyond the weekend with a deepening trough over the central US late Monday into Tuesday, however, the current deterministic model suite is still figuring out the general timing/location of a surface low traversing eastward across the Ohio River Valley and depth of cold air descending from Ontario. This will be a target of opportunity for future forecast packages as lake effect snow and colder temps could impact Thanksgiving holiday travel. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 706 PM EST Wed Nov 20 2024 Conditions will continue to deteriorate this evening as an area of low pressure pushes from east to west over the UP. Showers over the Eastern and Central UP will expand westward this evening as a mix of rain and snow. The rain snow mix transitions over to snow tonight, with IFR conditions developing at all sites after 06z. By 12Z, snow will transition back to rain, with IFR conditions persisting through the day on Thursday. Otherwise, northwest winds increase tonight, gusting up to 25-30 kts at IWD and SAW with up to ~35 kt at CMX for Thursday morning and early afternoon. && .MARINE... Issued at 429 PM EST Wed Nov 20 2024 Deepening surface low pressure rounding Lower Michigan and descending down the axis of Lake Michigan late tonight through Thursday will bring marine hazards to Lake Superior through Thursday evening. Northerly winds over central and east Lake Superior pick up late tonight, increasing above 25 knots around 7pm EST, and 35 knots just after midnight. By Thursday morning, the pressure gradient be comes maximized across the lake and gusts 35-40 knots expand across much of the lake, especially closest to the Keweenaw. A few stray gusts to 45 knots are possible (30%), particularly between 5-10am EST. As the surface low continues south and east Thursday evening, winds begin to slacken below gale criteria by at least 7pm EST while remaining out of the north. Into the weekend, northeast winds remain elevated on Friday around 25 knots with a few gusts to 30 knots, further lessening below 20 knots Saturday. Winds remain light through the early portions of next week, but could gust to 25 knots on Tuesday. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from 5 AM EST /4 AM CST/ to 2 PM EST /1 PM CST/ Thursday for LSZ162-263. Gale Warning from 6 AM EST /5 AM CST/ to 3 PM EST /2 PM CST/ Thursday for LSZ241>243-246-247. Gale Warning from 2 AM to 1 PM EST Thursday for LSZ244-245. Gale Warning from 1 AM to 1 PM EST Thursday for LSZ248>250-265- 266. Gale Warning from 2 AM to 3 PM EST Thursday for LSZ264. Gale Warning from 5 AM to 10 AM EST Thursday for LSZ267. Lake Michigan... Gale Warning from 3 AM to 1 PM EST Thursday for LMZ221-248-250. && $$ UPDATE...LC SHORT TERM...Jablonski LONG TERM...BW AVIATION...RM MARINE...BW
Area Forecast Discussion
National Weather Service Springfield MO
547 PM CST Wed Nov 20 2024 .KEY MESSAGES... - Below normal temperatures and dry conditions will occur across the area through the end of the week. - Temperatures increase to near normal/slightly above normal over the weekend into early next week. - Rain chances increase in the early to middle part of next week. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 245 PM CST Wed Nov 20 2024 Current water vapor imagery depicts a deep and north-south elongated mid- and upper-level low protruding into the Ozarks from the northern Midwest states. RAP analysis has a roaring 100-120 kt jet streak placed right over the Ozarks. Visible satellite shows a near-textbook comma head mid-latitude cyclone over the northern Midwest states with a cloud shield ahead of a cold/occluded front stretching all the way from the Great Lakes down to the Florida panhandle. WPC places a tertiary cold front associated with this dynamic system over central IA into central NE. Strong flow aloft overtop a tight backside pressure gradient is forcing gusty northwesterly winds with Springfield and Joplin briefly reaching above 40 mph gusts, but mainly our area is experiencing gusts of 30-35 mph. Cooler high temperatures in the middle 50s are also being experienced as cold air filtered in behind the secondary cold frontal passage last night. Near Red Flag fire weather conditions this afternoon: Paired with the observed gusty winds, dewpoints are also much drier than anticipated, with some areas such as Fort Leonard Wood, West Plains, and Springfield dropping below NBM 10th percentile. This is bringing widespread 20-30% observed relative humidity values to the region. Some localized areas may see relative humidity drop below 20% this afternoon as diurnal and mechanical mixing continue. This has resulted in widespread Elevated (2 of 4) to Significant (3 of 4) fire weather conditions. Some localized areas are flirting with Red Flag Warning criteria (<25% RH; >20 mph 20 ft winds, or >30 mph 20 ft wind gusts). Notably, Springfield, Roby, and Fort Leonard Wood have all briefly breached Red Flag, but only for short periods. Fuel moistures have also been drying out throughout the day and are hovering around 10% as of now (<9% is generally Red Flag). With all that being said, Red Flag is not being met in widespread areas and for long durations. Additionally, as the afternoon progresses past 3 PM, winds are expected to decrease and RHs will increase as temperatures cool with the setting sun. Therefore, a Red Flag Warning will not be issued at this time, but will continue to be closely scrutinized for any impactful dip well below criteria for a good portion of time. Nevertheless, it is important to continue to practice fire safety with conditions being borderline Red Flag. Below normal temperatures Thursday and Friday: The tertiary cold front will drop through the area late tonight as the upper-level low pivots to over the Great Lakes, positioning us below a tight NW`ly flow height gradient. This will allow even colder air to filter into the region. Lows tonight will be in the middle 30s and highs Thursday will be chillier in the middle 40s. Continued breezy 15-20 mph NW`ly winds (with gusts up to 25-30 mph) will create max "feels like" temperatures in the middle to upper 30s. Lows will be colder in the upper 20s which will be our second hard freeze since October 17th. The same pattern will remain fairly static into Friday night, withs highs in the middle to upper 40s and lows in the upper 20s again. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Issued at 245 PM CST Wed Nov 20 2024 The weekend pattern remains relatively benign, with near-normal temperatures Saturday and above-average temperatures in the mid- to upper 60s on Sunday thanks to a ridging pattern early in the weekend. General ensemble consensus is that the ridge will weaken into more of a zonal flow aloft, with the low-level flow breaking its omega block in the second half of the weekend. The "second half of the weekend" is intentionally vague- the timing window is wide, with cold frontal influence reaching us potentially as early as Sunday afternoon or as late as Monday morning. This is when our next precipitation chances are- though only 10-20% chances, with the highest chances in the eastern Ozarks where higher PW values will be. Temperatures will get colder again post-FROPA, with highs on Tuesday and Wednesday likely returning to the 40s and lows in the upper 20s-low 30s. Dry conditions will accompany the cooler temperatures. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 523 PM CST Wed Nov 20 2024 Skies will be clear through the next 24 hours despite a strong upper level are of low pressure over the Great Lake region. With this system over the Great Lakes, surface pressure gradients will remain tight allowing for gusty surface winds through the forecast. Winds will be the primary concern for aviators across the Ozarks. This will include low level wind shear late tonight and into Thursday morning. Wind shear will be prevalent near the boundary layer, around 2kft AGL from the northwest. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Price LONG TERM...Camden AVIATION...Hatch