Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/03/24


Area Forecast Discussion
National Weather Service La Crosse WI
709 PM CDT Tue Apr 2 2024 .KEY MESSAGES... - Rapidly evolving late-season system will continue to bring heavy snow across portions of West-Central Wisconsin. Highest amounts of 5 to 8 inches are expected in the area where a Winter Storm Warning is in effect with locally higher amounts, particularly on ridgetops. Amounts begin to lessen as you head west of the Mississippi River. - Increased Winds of 35 to 50 mph Move Through The Area Tonight Through Wednesday. Heavier Snow Will Limiting Blowing Potential However Impacts From Decreasing Visibilities Cannot Be Ruled Out - Lasting Impacts From Todays Low Pressure This Week Into The Weekend Remain Uncertain: Lingering Precipitation Potential And Weekend Synoptic Setup && .DISCUSSION... Issued at 250 PM CDT Tue Apr 2 2024 Banded Snowfall Continues Through The Afternoon: Snow, potentially heavy at times in localized bands will continue through the afternoon. As a surface low centered over MO/IL continues to push northeastward towards Lake Michigan, two forcing regimes have be noted across the region late this morning and into the afternoon. Over the course of this morning some bands of 500- 700mb frontogenesis allowed for fairly intense snowfall rates with a wide range of snowfall reports depending on residence time in heavier snow bands. As a result, impacts vary over short distances resulting in rapidly snow-covered roads in spots with heavy snow rates. When precipitation lightens, improvement in road conditions has been noted. As the rest of the afternoon continues, the precipitation shield northwest of the low will continue to progress through the region as the low continues to deepen. Consequently, have decided to expand the Winter Weather Advisory further west with a start time at 18z to account for the ongoing conditions. Snow Overnight Tuesday and Wednesday, Highest Accumulations are expected across West-Central Wisconsin: As we begin to head into the overnight, snow will persist as the aforementioned low pressure system begins to deepen dramatically across the Lake Michigan to around 980mb overnight. Furthermore, the recent runs of the RAP continue to indicate a strong 600mb frontogenesis signal moving in during the overnight which when considering an increasing westward extent in the 02.12z snowfall rates probabilities of 1" per hour or greater in Adams and Juneau counties. Therefore, decided to expand the Winter Storm Warning to include Monroe, Vernon, and Richland counties to account for this signal with the 02.12z HREF having very high probabilities (80-100% chance) of 6 inches or greater. While there is a significant signal in the recent CAMs for high snow totals, there remains some caveats to this. First, the highest totals will likely pertain to the ridgetops where thermodynamics and surface temperatures will be more favorable and snow to liquid ratios will be higher. Furthermore, what remains uncertain with this is how localized frontogenesis features will pan out throughout the rest of the event. As has been noticed this afternoon locally where a very narrow, persistent, frontogenesis band has been situated over portions of the La Crosse area. Additional features could present themselves overnight in this fashion which could lead to more dramatic differences in snow totals. Lastly, compaction of the snowfall due to its wet, heavy nature may limit snow totals as well. In short, many factors may result in snow totals and rates varying substantially which could make travel quickly hazardous this evening and overnight. As a result, generally expecting 5 to 8 inches in the warned areas with higher localized amounts where narrow bands set up and along ridgetops. As Wednesday afternoon approaches, snow will persist but guidance generally keeps rates lower which will should limit additional accumulations to some degree and help road conditions improve as the higher sun angle and relatively warmer temperatures should help melt off roadways. Winds will increase substantially by afternoon which could still result in some more reduced visibilities at times with falling snow but generally expecting rates to lighten by the afternoon. * WINDY! late tonight into Wed evening with gusts 35 to 50 mph Sfc low paired with the southern stream shortwave trough set to track over southern lake michigan this evening, showing some retrograding westward as a shortwave in the northern stream digs into/merges with the southern feature. Deepening sfc low/tightening sfc pressure gradient develops...with the tighter gradient sitting across the upper mississippi river valley tonight into Wed evening, before relaxing later Wed night through Thu. Latest RAP steaks a southward moving 50+ kt 850 mb jet across the local forecast area by 06z tonight, late tonight, holding into mid evening Wed. RAP soundings also show unidirectional winds in the vertical, through at least 850 mb, and good mixing into those stronger low level winds. Latest HREF probabilities for 40 mph gusts are 70-90% through this period, with a 30-50% to exceed 50 mph. With confidence high in wide spread, strong/impactful winds...will issue a wind advisory for the entire forecast area from late tonight into Wed evening. How the wind interacts with the falling and fallen snow is not as clear. The wet, heavy nature of the snow will generally inhibit significant blowing/drifting. However, snow sticking to trees, branches, etc could create a heavy enough load that coupled with the strong winds could result in downed branches, etc. Perhaps some power outages. Certainly another potential hazard to be on the look out for. * NEW WEEK PCPN CHANCES: Sun/Mon showing the higher chances right now, mostly rain Long range guidance in good agreement with rotating an upper level shortwave trough northeast out of the central plains and across the upper mississippi river valley Sun into Mon. GEFS/EPS at odds with how to handle the parent upper level low - some bring it west-east across the region while others slowly meander it northeast into Canada. The upshot though is the preponderance of the GEFS/EPS ensemble members paint light QPF across the region Sunday, lingering into Monday. Model blend suggests a 40-50% chance for 1/10" liquid with less than 20% for 1/4". The EC is more bearish on the chances and up those percentages by 10-20%. Current temperatures would favor rain, but can`t completely rule out snow mixing in here and there. EC suggests only a 30% for measurable snow for southeast MN, little to no threat elsewhere. GEFS/EPS then show some potential for a southern stream shortwave trough to slide across southern portions of the region for mid week, bringing another shot for pcpn - trending just rain. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 657 PM CDT Tue Apr 2 2024 Variable conditions across the region with VFR conditions near and west of KRST and LIFR conditions at KLSE with snow. A storm system over Michigan will combine with another storm system pushing through Minnesota over Illinois and Indiana. This will keep the TAFs under cyclonic flow with snow bands wrapping around it through the forecast period. IFR/LIFR conditions are forecast to return/continue at both TAF sites tonight with periods of light to moderate snow. Conditions may at times improve to MVFR, however the lower visibilities should last at KLSE through much of the TAF period. Northwest winds 15kts and gusty at KRST will strengthen 20-30kts with gusts 32 to 42kts at both sites and continue through Wednesday. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Wind Advisory from 1 AM to 10 PM CDT Wednesday for WIZ017-029- 032>034-041>044-053>055-061. Winter Weather Advisory until 10 AM CDT Wednesday for WIZ017- 029-034-041-054-061. Winter Storm Warning until 10 AM CDT Wednesday for WIZ042>044- 053-055. MN...Wind Advisory from 1 AM to 10 PM CDT Wednesday for MNZ079- 086>088-094>096. Winter Weather Advisory until 10 AM CDT Wednesday for MNZ096. IA...Wind Advisory from 1 AM to 10 PM CDT Wednesday for IAZ008>011- 018-019-029-030. Winter Weather Advisory until 10 AM CDT Wednesday for IAZ011- 030. && $$ DISCUSSION...Naylor/Rieck AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Cleveland OH
858 PM EDT Tue Apr 2 2024 .SYNOPSIS... Low pressure over the Midwest will continue to shift northeast before occluding tonight over Michigan. An associated warm front will lift north this afternoon, followed by a cold front tonight. This low will eventually shift off the East Coast on Thursday, allowing for a high pressure to build in for the weekend. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... 900 pm update... We are cleaning up and taking the severe weather potential out of the forecast for the rest of the evening. That potential has drastically decreased over the past couple of hours. We will likely allow the Flood Watch to expired before 10 pm as well. 700 pm update... The next several hours is a wait and see kind of game. We are still under a severe weather threat with the greatest risk area along and south of Highway 30 this evening. SPC is monitoring our central Ohio counties for a possible new Tornado Watch. See the SPC MD #357 for more information. Previous update... The 330 PM update simply extends the discussion to include Wednesday and Wednesday night at the bottom of the current discussion. No changes were made with the immediate forecast. Discussion... Over the last couple hours, there is quite a lot constantly changing and evolving so opted to completely update the forecast into Wednesday morning. Looking at the big picture, there is a surface low centered near the southern tip of Lake Michigan which is associated with an upper level trough beginning to push south across the western Great Lakes region. With the trough continuing at amplify, the surface low is continuing to deepen, already dropping to 993mb and forecast to drop to near 985mb. A warm front extends east from this low across the CWA, currently located near the US30 corridor. This front is expected to continue to push north, although the exact extent remains a bit uncertain. Taking an average location amongst models, it should shift north to at least US-224. Ahead of this boundary, current temperatures linger in the 40s with dewpoints in the 40s, but behind it temperatures are climbing into the low 60s with dewpoints in the mid to upper 50s. The biggest question is how these surface conditions will evolve in the next couple hours, especially with ongoing convection across southwest OH and southern IN. Digging a bit more into the mesoscale aspect, there is certainly still a potential for severe weather this afternoon, although timing of it looks to be a bit later than previously forecast, possibly closer to 5-10PM now. Overall shear with this event remains very high with bulk shear values exceeding 70 knots across Ohio. How much instability will climb this afternoon has quite a bit of uncertainty, particularly in relation to if the dewpoints/low level moisture will be able to rebound north of the ongoing convection south of the area. On water vapor imagery and looking at surface obs, there does appear to be a small corridor were higher moisture is advecting north near the I77 corridor, but once the convection moves east, this may be cut off. The breaks in clouds this afternoon have not been sustained long enough to substantially destabilize the atmosphere, so it will be highly dependent on if dewpoints above 60 can push far enough north. Will know more in the next couple hours as the upstream convection evolves. Shifting into the evening, near 00Z, the cold front will begin to push east and enhance surface lifting along the boundary. At that point, convection mode will primarily be linear, but that doesn`t diminish the threat for strong to severe storms. Near that time, the RAP increases the Supercell composite parameter to 4 and the latest WoFS run increases STP values near the CWA`s southwestern border as a LLJ pushes northeast across the area. This additional enhancement from the front and LLJ may provide enough surface based lift for storms to pose numerous hazards. With all that being said, SPC in collaboration with WFO CLE has kept areas along and south of US30 in an Enhanced Risk (3 out of 5) of severe weather, with strong winds (gusts up to 80 mph), large hail (up to 1 inch), and tornadoes all possible. North of that, the area remains in Slight Risk (2 out of 5). In addition to the severe weather potential, a Flood Watch is in effect for counties along and south of US30. PWAT values exceeding 1 inch coupled with very wet antecedent conditions from last night/this morning`s convection have made the area prime to flood potential. If there is any silver lining, hodographs suggest storm motion will be quite quick with limited risk of training. However, in the strongest storms rainfall rates may approach 1-2"/hr. Additional impacts to rivers, urban areas, and low lying areas are expected through this evening. To account for this, WPC has maintained a Day 1 Slight Risk ERO for eastern Ohio. Near midnight tonight, showers will gradually begin to dissipate from west to east as the cold front moves east. As the low pressure continues to deepen, upper level support on the eastern side of the trough will maintain precipitation across eastern Ohio/Northwest Pennsylvania into Wednesday afternoon. Scattered thunderstorms will remain possible, but the severe threat will greatly be diminished. Showers will linger through Wednesday night as the upper level low continues to pivot over the region. Showers should generally be light, but with colder air pushes south behind the low, have opted to introduce a rain/snow mix to the forecast. No accumulation is expected however. Overnight lows tonight will drop into the upper 30s out west and into the mid to upper 40s for the eastern counties. High temperatures tomorrow will be a bit cooler, only climbing into the mid to upper 40s. Overnight lows on Wednesday night will definitely be much cooler, dropping into the low to mid 30s. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... The short term period will begin with a weakening closed-low across the Lower Great Lakes, with wrap-around moisture resulting in periodic rain and snow showers through Thursday. Surface temperatures will remain fairly marginal, hovering at or above freezing as the closed-off low should limit any of the colder air across portions of southern Canada/the Upper Midwest from entering the region. Could see a brief uptick in rain/snow intensity Thursday afternoon/evening as a surface trough swings south across the Eastern Great Lakes. Wouldn`t be surprised to see up to an inch of wet snow accumulation in any heavier and more persistent bands. Lingering surface troughing should allow for continued rounds of rain and snow showers with perhaps some lake-enhancement possible late Thursday night into early Friday as a colder air mass, characterized by 850 mb temperatures between -8 and -10 degrees C, will arrive across the region. Temperatures will be below average through the short term period with highs generally in the 40s under persistent cloud cover and periodic rain and snow showers. && .LONG TERM /SATURDAY THROUGH TUESDAY/... Exact details for the April 8, 2024 Eclipse remain fairly uncertain, although confidence is increasing in at least some upper-level cloud cover arriving into the area late Monday morning into the afternoon. For this forecast package, maintained about a 60-70% cloud cover in addition to a low chance (30%) of light rain across the area for Monday afternoon. Ensemble clusters continue to suggest the potential for high cloud cover to arrive on Monday, although there are subtle hints that some mid-level cloud cover may also develop if rain chances trend higher. The current temperature forecast across the region on Monday remains largely unchanged with highs reaching the low to mid-60s. Otherwise, no impactful weather systems are expected for Saturday, Sunday, or Tuesday as above-average temperatures in the 60s return across the region by Sunday and beyond. && .AVIATION /00Z Wednesday THROUGH Sunday/... We have a variety of conditions ranging from LIFR in TOL to VFR in CLE and everyone else in between. The general aviation message going forward will be MVFR to IFR ceilings tonight and lasting through Wednesday afternoon. Towards the end of the TAF period, MVFR to maybe VFR ceilings are expected. There is still a chance for a few strong to severe storms this evening between 00z and 04z for MFD, CLE, CAK, and YNG. Have mentioned VCTS with TEMPO groups for -TSRA if impacts are expected at specific TAF site. Scattered -SHRA will linger till about 06z to 09z overnight mainly over the eastern areas. South of the warm front, southerly winds 12 to 15 knots with gusts up to 20 knots are expected this evening. North of the warm front, easterly winds around 10 knots are expected this evening. Eventually a cold front will move through overnight with winds becoming southwesterly 5 to 12 knots after 06z through the end of the time period. Outlook...Non-VFR possible in rain/snow showers and low ceilings Wednesday evening through Friday. && .MARINE... Rough marine conditions will continue through this evening as east to northeast winds of 15 to 25 knots persist. Winds will shift towards the south as a warm front lifts north across the lake tonight. Southwest winds are then expected to persist across the lake on Wednesday and Wednesday night. Small Craft conditions may return again late Thursday as north to northwest winds of 15 to 20 knots arrive behind a trough. Elevated north to northwest flow of 15 to 20 knots and the potential for Small Craft conditions are expected to persist through Friday night and perhaps into early Saturday. Strong to severe storms are possible across the Lake this evening. Damaging wind gusts, large hail, and the potential for waterspouts are all possible. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Flood Watch until 11 PM EDT this evening for OHZ027>033- 036>038-047. PA...None. NY...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for LEZ142>149. && $$ SYNOPSIS...Campbell NEAR TERM...Campbell/Griffin SHORT TERM...Kahn LONG TERM... AVIATION...Griffin MARINE...Kahn
Area Forecast Discussion
National Weather Service State College PA
1143 PM EDT Tue Apr 2 2024 .SYNOPSIS... -Additional 1.5-3" of rain will maintain elevated inundation and river flood risk into Thursday -Breezy and cooler end to the week with rain and snow showers ending on Saturday -Milder Spring weather pattern returns next week with above average temperatures && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... The focus for tonight will be on the approaching low level jet linked to a deepening upstream trough. As this feature and its associated plume of anomalous pwats overruns the cool/stable airmass across Central PA, expect rain to redevelop across the western counties late this evening and spread into the eastern counties late at night. Large scale forcing/upper level divergence ahead of the upper trough, combined with surging pwats and some elevated instability, should result in convective elements within the stratiform rain with thunder possible in some spots. Ensemble mean qpf of between 0.5 to 1 inch represents the most likely 12hr rainfall amounts overnight. However, locally higher amounts are likely with any tsra. Both the 12Z HREF and most recent HRRR indicate local amounts of 1.5 inches are possible over the western half of the forecast area tonight. Given the already wet ground, this could potentially result in minor flooding issues. The 18Z 3HR FFG numbers range from 1 to 1.5 inches, with the most susceptible area over Clearfield and Northern Cambria counties. Although cold air damming will remain in place, a tightening gradient ahead of the approaching cold/occluded front will result in increasing east to southeast winds. Latest Bufkit soundings support gusts to around 35kts by dawn over the NW Mtns and also over the Western Poconos. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/... Strong forcing ahead of the deep/closed H5 trough, combined with a plume of anomalous pwats surging northward along eastward advancing cold/occluded front will locally heavy rain to the area on Wednesday. This area of heavier rain looks to be focused in the 12-18Z window over south central and southeastern portions of the area with HREF PMM values suggesting spot amounts may exceed 1.5 inches. The heavier rain should peel off to the north and east during the afternoon and evening as cooler/drier air starts to work into southwest PA between primary and secondary/triple pt sfc lows (dry slot). Expect precip to taper to showers Wednesday night in the wake of the frontal passage. A very tight pressure gradient is progged around midday Wednesday across Eastern PA Wed, to the north of a developing secondary low over Virginia. Latest model soundings support a likelihood of at least some wgusts in excess of 40kts, particularly downwind (northeast) of the ridgetops over the Western Poconos. The combination of wet ground and gusts over 40kts increases the threat of downed trees. Will reassess the need for a wind advisory with the 00Z guidance. Colder air filtering into the area Wed night will result in rain or wet snow ptypes at elevations generally AOA 13-1500ft with all snow >2000ft. A minor snow accumulation (coating up to 1 inch or so) is possible on the ridgetops and highest terrain by Thursday morning. Rain and snow (showers) continue Thursday underneath the closed H5 low with temps bottoming Thu-Fri. Sfc-700 hPa lapse rates will be impressive beneath the upper trough Thu afternoon. This should support numerous scattered diurnal rain/snow showers with graupel and perhaps even a few lightning strikes. SWO D3 general thunder over western PA remains supportive of the low topped convection. Unseasonably cool cyclonic flow on the backside of departing upper low will maintain rain and snow showers over the Alleghenies with some showers or flurries spilling toward the lower Susq Valley. Elevation driven wet snow accums remain possible especially Thu night into Friday morning. Max temps trend colder through late week with highs 10 to 20 degree below average by Friday in the mid 30s to upper 40s. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Near vertically stacked low over Down East Maine Friday night will keep the CWA under a deep, well-aligned and unseasonably cold NW flow that will start the weekend with plenty of clouds with scattered AM snow showers over the N Mtns. The upper low is progged to lift away from the region the second half of the weekend, with rising heights resulting in fair and seasonable conditions Sunday. Upper level ridging over the region should result in warmer and generally dry weather early next week. However, can`t rule out a few showers Monday PM or Tuesday associated with a slow moving warm front over the Ohio Valley. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... A mix of MVFR and IFR conditions is being observed this evening across Central Pennsylvania. Low pressure over the Ohio Valley will continue to bring multiple rounds of rainfall to the area through the day on Wednesday. All guidance supports ceilings lowering to IFR/LIFR by 06Z for the entire area. Visibility restrictions will also be likely, with the greatest reductions occurring in the heaviest rain. Ongoing convection across Ohio will approach the area beginning around 03Z. It will be on a weakening trend, but there should be enough elevated instability to allow for at least a few lightning strikes for western sites. There are still some questions about how far east the threat for lightning will extend. A 40 to 50 knot low level jet moving in from the west will lead to the development of low level wind shear tonight and into the morning for the western half of the area. Decided to remove LLWS from the TAFs for eastern sites as model soundings show the strongest winds remaining above 2000 feet. Winds will become gusty in the morning and into the afternoon for sites in the Lower Susquehanna Valley (MDT, LNS) as the pressure gradient tightens in response to a developing low pressure system off the east coast. Guidance supports gusts of 30 to 35 knots with sustained winds of 10 to 20 knots. Outlook... Wed Night...Lingering showers with restrictions likely. Thu...Colder air moves in and lingering rain showers will mix with or change over to snow showers across higher elevations. Fri-Sat...A few snow showers possible, mostly KJST and KBFD. Sun...Skies clearing throughout the day. && .HYDROLOGY... Previous/ongoing rainfall continues to saturate the ground with considerable responses already on some small streams and creeks. With an additional 2-3 inches (locally up to 4) of rain forecast through Wednesday night, we now expect over a dozen (13) river points to approach/potentially exceed minor flood stage. Can`t rule out a moderate flood in some of the favored locations in the Juniata Basin. Williamsport and Harrisburg are now both expected to exceed action stage and approach minor flood stage on Thursday into Friday. && .CLIMATE... After one of the warmest starts to March on record, temperature departures were near to below average during the second half of the month. Here are the March 2024 temperature rankings: Harrisburg: Avg. temp 46.3F (+4.5F, 12th warmest) Williamsport: Avg. temp 44.5F (+5.8F, 10th warmest) Altoona: Avg. temp 44.9F (+6.2F, T4th warmest) Bradford: Avg. temp 40.2F (+7.2F, 3rd warmest) && .CTP WATCHES/WARNINGS/ADVISORIES... Flood Watch through Thursday morning for PAZ004>006-010>012- 017>019-024>028-033>037-041-042-045-046-049>053-056>059- 063>066. && $$ SYNOPSIS...Steinbugl NEAR TERM...Fitzgerald SHORT TERM...Fitzgerald/Steinbugl LONG TERM...Fitzgerald AVIATION...Bauco HYDROLOGY...Steinbugl CLIMATE...Steinbugl
Area Forecast Discussion
National Weather Service Dodge City KS
902 PM CDT Tue Apr 2 2024 .KEY MESSAGES... - Dry, warming trend is expected through the rest of the work week. - Powerful weather system on Saturday could bring severe thunderstorms to our area favoring the eastern zones, but limited moisture will be a significant limiting factor. - Much better opportunity for widespread precipitation exists late in the forecast period as another weather system takes aim at the central plains. && .UPDATE... Issued at 902 PM CDT Tue Apr 2 2024 No significant changes to the going forecast. Infrared satellite imagery depicts a patch of midlevel cloud that will be moving southeast across SW KS the next few hours. Vigorous NWly flow through the depth of the atmosphere will continue Wednesday, in response to a powerful 522 dm closed cyclone near Chicago. Expect NW winds to pick up rapidly after mixing begins around 10 am, with winds of 20-30 mph common. Observed gusts on Tuesday were near 45 mph; they are expected to be a bit weaker, around 35 mph Wednesday. Models do show a net warming of 2-3C at 850 mb, and warmed forecast temperatures Wednesday afternoon about 2 degrees, with mid to upper 60s common across central and western zones. The forecast high at DDC Wednesday is 66, and the normal high for April 3 is 66. Few if any clouds expected Wednesday in a strongly subsident regime. && .SHORT TERM /THROUGH THURSDAY/... Issued at 200 PM CDT Tue Apr 2 2024 Recent water vapor satellite loop and RAP upper air analysis indicate an upper level trough axis extends from the northern Midwest southward to northern MO, and southwestward from there through the southern plains and into northern Mexico. At the surface, a ~993-mb low is centered over north-central IL, with an expansive pressure field around it reaching all the way westward to the Rocky Mountains. This is the source of the strong northerly winds southwest KS is experiencing today, and these will be maintained despite the surface trough pulling farther away as an upper level shortwave digs southward on the western periphery of the parent trough and deepens the surface low. Resulting cold air advection will act to offset the strong early-April sun somewhat, supporting afternoon highs only in the upper 50s/low 60s. Overnight, winds will weaken substantially with the loss of boundary layer mixing, and combine with clear skies to allow temperatures to drop into the low/mid 30s. Daytime Wednesday, upper level ridging will continue to build over the western CONUS as the typical mid-spring wave train within the subtropical jet persists. However, northerly winds will increase once again as southwest KS remains within reach of surface low`s influence, especially across the eastern zones. As a result, afternoon highs will range from the upper 60s/low 70s west to the upper 50s/low 60s east. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... Issued at 200 PM CDT Tue Apr 2 2024 Medium range ensembles have changed little compared to this time yesterday regarding the evolution of the synoptic pattern through the end of the work week, suggesting the upper level ridge over the western CONUS at the beginning of the long term period will slide east with time, and pass overhead on Friday as another powerful trough moves in behind it. Therefore, expect a warming trend these days as afternoon highs increase from the mid 60s east to mid 70s west Thursday to the low/mid 70s east to upper 70s/low 80s west Friday. On Saturday, the aforementioned significant, negatively-tilted upper level trough will eject onto the High Plains. Southwest KS is lucky poor moisture return is expected ahead of this trough as shown by NBM probability of SBCAPE exceeding 500 J/Kg of less than 40%, otherwise this wave would be ideal for high-end severe weather potential. That said, severe convection across our area cannot be ruled out as a sharpening dryline placed somewhere around our central CWA provides the focus for thunderstorm development within a strongly sheared environment during the afternoon. Daytime Sunday, as the upper level trough continues to eject onto the High Plains, the EPS and GEFS both agree southwest KS will be within the cyclone`s dry slot as probability of QPF of 0.1" is 0% across all zones. However, ensembles suggest this will not be the case for the next upper level wave that will reach the central plains near the end of the period. Thanks to this cyclone`s much farther south track allowing it to tap into Gulf of Mexico moisture more effectively, ensemble probability of QPF exceeding 0.1" is in the 60-80% range for all zones. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 430 PM CDT Tue Apr 2 2024 VFR/SKC will continue through this TAF period, with limited amounts of scattered mid/high clouds. Strong north winds gusting to near 40 kts at 2130z will weaken rapidly by 02z Wed, with light NW winds prevailing overnight through 15z Wed. After 15z Wed, strong NW winds will return to all airports, but at speeds a bit less than those observed Tuesday, with gusts of 30-33 kts. && .DDC WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Turner SHORT TERM...Springer LONG TERM...Springer AVIATION...Turner
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1100 PM CDT Tue Apr 2 2024 .KEY MESSAGES... - Light snow will continue across western Wisconsin into the evening, with accumulations around an inch or so possible. - Strong northerly winds expected Wednesday. Wind Advisory issued across western Wisconsin and southern Minnesota, where gusts up to 45 mph will be possible. - Temperatures warm through the end of the week, with highs in the 50s this weekend. && .DISCUSSION... Issued at 225 PM CDT Tue Apr 2 2024 Early afternoon visible satellite reveals a very active picture across eastern CONUS. The headline storm system centered across Illinois is responsible for a multitude of weather concerns, including a potential severe weather outbreak in the Ohio Valley/Deep South and several inches of snow from eastern Wisconsin into the Upper Peninsula of Michigan. A less notable, but important secondary feature in the form of an upper-level shortwave tough is digging into the eastern Dakotas and western Minnesota. Both of these features are forecast to phase through tonight, with the resultant deep ~980s mb low progged to spin over the Great Lakes through the second half of the work week. The morning round of light snow that moved through eastern Minnesota and western Wisconsin can be tied to the headline storm system in central Illinois. Deformation banding northwest of the low, supported by a band of 700 mb frontogenesis, worked in tandem to produce the burst of snow that moved across the area for the morning commute. The deformation band has since shifted east of the Twin Cities, though will likely continue to produce light snow in western Wisconsin through this evening (supported by the northeast track of the surface low). It still appears that the heaviest snow will fall across central/eastern Wisconsin, such that our expectations have not changed all that much. Most of our western Wisconsin communities will observe an inch or less of snow, however it`s conceivable that counties on a line from Pepin northeast to Rusk pick up an additional 1-2" through tonight. Further west, the approach of the upper-level wave will bring the reintroduction of PoPs across western Minnesota this afternoon and evening. As is typical in a cold air advection regime, there will be a "convective" nature to the precipitation chances. These scattered showers will likely vary between rain/sleet/snow and could even include and isolated rumble of thunder, owing to slim CAPE profiles captured on RAP forecast soundings. Given the presence of low freezing levels and support for moderate updrafts, it`s also possible that small hail falls beneath the strongest cores. Recent satellite imagery has captured an uptick in the Cu field across NW Minnesota, ahead of the approaching wave. CAM guidance is in good agreement that the best chance for these convective showers will be west of the I-35 corridor, beginning in the next few hours and then winding down before 9/10 PM or so. We do not expect much in the way of accumulation, should snow be the p-type within these showers, however brief reductions in visibility are certainly possible. Lows tonight are projected to fall only a few degrees below freezing, so a widespread "ice rink" appears unlikely, however we will watch for some of the wet roads to become slick heading into the morning commute. On Wednesday, the forecast theme will switch from precipitation chances to concerns with strong northerly winds. As mentioned above, the upper-wave will phase with the surface system to the southeast, ultimately promoting deeper surface low pressure. A tight pressure gradient will setup on the northwest region of said system, such that concerns with the winds fields will arise heading into tomorrow. Wind gusts will begin to approach advisory criteria across western Wisconsin after midnight and will spread west into eastern/southern Minnesota by daybreak. A very windy Wednesday is expected, as sustained northerly winds will range between 25-30 mph. Gusts as high as 45 mph will be possible for an extended period. We`ve collaborated with neighboring offices to issue a Wind Advisory for western Wisconsin and all of southern Minnesota, including the Twin Cities metro. While it will still be breezy Thursday morning, significant improvements in the forecast are on tap for the end of the work week. High pressure will signal more pleasant weather by Thursday afternoon, with highs in the upper 40s and low 50s. Temperatures will warm into the low 50s Friday and then climb further into the mid to upper 50s on Saturday. A weather system will bring the return of rain chances for Sunday and Monday (perhaps not great news for those hoping to observe the partial eclipse from the Upper Midwest). Trends continue to climb well above average in the extended period, with highs in the low 60s by the middle of next week. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 1056 PM CDT Tue Apr 2 2024 Steady snow with MVFR/IFR conditions will continue tonight across western Wisconsin and impact KEAU. Farther east, light snow will affect KMSP and KRNH along with MVFR clouds, but visbys should remain VFR and most of the snow will melt on contact. Farther west, skies will be more scattered, with higher ceilings, so should have generally VFR conditions at KSTC, KAXN, KRWF, and KMKT. Looking ahead, northerly winds will increase overnight with gusts near 35 kts on Wednesday. KMSP...The snow has arrived at KMSP, and it will continue for a few hours overnight. Expect visbys to remain above 3 miles, and snowfall rates will be light enough that it will melt on contact so no accumulation is expected. Winds will be out of the north with gusts of 35 to 40 kts possible Wednesday afternoon. /OUTLOOK FOR KMSP/ THU...VFR. Wind N 10-15kts. FRI...VFR. Wind E 10kts. SAT...VFR. Wind SE 10-15kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...Wind Advisory from 5 AM to 10 PM CDT Wednesday for Anoka-Blue Earth-Brown-Carver-Chippewa-Dakota-Faribault-Freeborn- Goodhue-Hennepin-Lac Qui Parle-Le Sueur-Martin-McLeod- Nicollet-Ramsey-Redwood-Renville-Rice-Scott-Sibley-Steele- Waseca-Washington-Watonwan-Yellow Medicine. WI...Wind Advisory from 5 AM to 10 PM CDT Wednesday for Barron- Chippewa-Dunn-Eau Claire-Pepin-Pierce-Rusk-St. Croix. && $$ DISCUSSION...Strus AVIATION...JRB
Area Forecast Discussion
National Weather Service Marquette MI
927 PM EDT Tue Apr 2 2024 .KEY MESSAGES... - Strong spring storm system runs through Wednesday night. Combination of strong winds and heavy wet snow will lead to power outages and tree damage, potentially widespread. - Marquette and Baraga counties upgraded to Blizzard Warnings for tonight and Wednesday. Winter Storm Warnings elsewhere. Travel will be difficult to impossible across much of the warned areas, and should be restricted to emergencies only. - Widespread 20 to 25 mph winds with gusts up to 35 to 45 mph expected across Upper Michigan. Gusts as high as 50 to 55 mph possible along Lake Superior, in the Keweenaw and along the Bay of Green Bay. This will result in power outages, downed trees, and drifting snow. - Widespread 4-12 inches expected, least in the east. Snow amounts in excess of 1-2 feet expected across the high terrain of Marquette and Baraga Counties into Thursday morning. - Temperatures will trend to above normal by next weekend. && .UPDATE... Issued at 920 PM EDT Tue Apr 2 2024 Water vapor imagery and RAP analysis show a sharply digging northern stream wave dropping thru MN into IA in the process of phasing with a very well-defined southern stream wave that has lifted over southern Lwr MI in response to the northern stream wave. Satellite presentation on WV and IR imagery is outstanding. At the sfc, low pres is centered over Lake MI to the se of Sheboygan. Strong forcing is supporting mdt/hvy pcpn to the nw and n of the low. This mdt/hvy pcpn has been slowly advancing northward this evening with leading edge -ra or a mix of -ra/-sn before changing to all snow. Some lightning has recently occurred over the Garden Peninsula with 4 cg strikes detected. Out over the western fcst area, -sn has been occurring more in response to the northern stream wave. Power outages have already occurred across s central into eastern Upper MI due simply to gusty winds and also gusty winds/snow accumulations. Outages will no doubt increase in coverage as hvy/wet snow spreads across the area during the night. Recent report from near Daggett indicated 4.3 inches of hvy/wet snow so far with power out. Observer could hear trees popping, and 2 trees in the yard have broken. Fcst appears to be in good shape, and updates so far this evening have been to better capture the advancing main pcpn shield. Mdt/hvy snow will continue to spread n and w overnight, and will set the stage for several hrs of very hvy snow across the higher terrain of n central Upper MI under strongly upsloping low-level ne flow. Tree damage/power outages will increase in coverage as hvy/wet snow spreads across the area during the night, and there are definite concerns that outages could become widespread across the s central and eastern fcst area where snow is definitely wet and sticking to everything. If the snow in n central Upper MI ends up wet enough to stick significantly on trees and powerlines, that will diminish the blizzard aspect to this storm somewhat, but power outages and tree damage could become very significant given the expected snow accumulations. In addition, the wet/sloppy snow will make travel very difficult, becoming impossible where plowing does not occur. Travel should be avoided tonight/Wed morning. && .SHORT TERM /THROUGH WEDNESDAY NIGHT/... Issued at 352 PM EDT Tue Apr 2 2024 Powerful late season storm to impact Upper Michigan beginning tonight... Latest water vapor imagery shows a mid-level trough extending from central Canada into the northern Plains/Midwest. A strong southern stream shortwave is noted lifting ne through northern IL through the base of this trough while northern stream shortwave is digging south through northern MN. Models indicate the shortwave energy from these jet stream branches are forecast to phase later this evening resulting in a rapid deepening of the associated sfc low now 992 mb over northern IL to 981-983 mb over central Lake Mi later this evening. The combination of strengthening mid-level fgen, strong deep layer Q-vector convergence, strong 290k sfc isentropic ascent and mixing ratios of 3-4 g/kg will bring a widespread 3-8 inches of snow into tonight across the U.P. with the highest amounts of nearly a foot over the higher terrain of western Marquette and Baraga counties where best forcing, terrain and lake enhancement could occur in a N-NE flow off Lake Superior. Precip will start out as rain or a rain/snow mix east and south central before changing over to mostly snow later this evening. The potential for heavy snow combined with blowing snow from north-northeast winds gusting to 35-45 mph has prompted the issuance of a Blizzard Warning for Marquette and Baraga counties for tonight into Wednesday. Winter Storm Warnings will continue for the rest of west and central Upper Michigan tonight into Wednesday or Wednesday evening. Travel will become difficult to nearly impossible, especially over north central portions of the U.P. later tonight. The combination of wet snow and strong winds will also have the potential to cause tree damage and power outages. The lesser amounts of snow (1-4 inches) should occur over the western U.P tonight, away from the better forcing from the system. Min temps tonight will be in the upper 20s to lower 30s. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 307 PM EDT Tue Apr 2 2024 Main item of interest in the extended period is the continuation of hazardous winter weather across the forecast area. Models all suggest that a very impactful system will lift into the region later today, persisting into Wednesday and Thursday night. With the NAM/NAMnest coming around to this idea with yesterday`s late runs, confidence is very high (>90%) that the combination of heavy wet snow and strong winds will result in dangerous or even impossible travel conditions at times. By Wednesday morning, ensemble systems and deterministic guidance suggest the surface low will be somewhere between Ludington/Grand Haven/Milwaukee/Manitowc. Regardless of where in this box, models place the surface low, each solution suggests strong northeast flow, strong fgen and strong dynamic forces, orographic enhancement, minor lake enhancement, and ample moisture will maintain moderate to heavy precip across the forecast area. The overall precip trend will be for widespread precip to continue through the day Wednesday and Wednesday night. Conditions overnight Wednesday should begin improving across the South Central late Wednesday night. All areas should trend toward dry Thursday, with the last hold outs being the elevated locations near Lake Superior of Marquette and Baraga counties likely late in the day. Model soundings show ptype for most, if not all, locations in the forecast area will start off as snow in the morning. Soon after sunrise though, I`d expect enough warming to begin taking place for precip to begin transitioning over to rain across the east and south. Any precip in these spots Wednesday evening and overnight should again to fall as additional snow. The EPS and GEFS all suggest 80% or higher chances for the central portions of Upper Michigan to exceed an inch of QPF; this, while the same guidance suggests 50% or higher across the east and west. Deterministic solutions paint most of the region with 1-2 inches of QPF and the high terrain of Marquette and Baraga counties with 2-3 inches. Given Lake Superior is ice free and the airmass is only marginally cold, all snow will be heavy and wet. The same models all suggest this will yield snow amounts of 1 to 2 feet across the area. However, this assumes a 10:1 snow ratio. When considering daytime heating, an ice free Lake Superior, and terrain enhancement, snow ratios should vary greatly across the region. With this in mind, reduced snow ratios in this forecast package based on daytime heating and proximity to the lakeshores to around 3-8ish:1 during the day Wednesday but maintained the 10-14ish:1 elsewhere. This should yield an additional 1-5 inches for these areas. Across the north-central though, the upslope enhancement should continue to maintain heavy snowfall and the 1 to 2 feet, or more of additional snow are still expected. While this is lower in some areas for the event then previous forecasts, it does not reduce the impact, as the snow will still be heavy, wet, and combined with strong winds. Strong pressure gradient forces are also expected with this system, which yields a high likelihood (>75%) for winds to exceed 35 mph across most of the forecast area Wednesday. Higher winds, of 40-50 mph should be expected in the Keweenaw and near Lake Superior. Winds should gradually weaken across the interior east in the afternoon and then Wednesday night into Thursday region-wide. These strong winds, coupled with the moderate to heavy snow, will yield dangerous to impossible travel conditions. Power outages, tree damage, and snow drifting will be possible. Because Marquette and Baraga counties will see the heaviest snow and these strong winds, opted we opted to upgrade the Winter Storm Warning to a Blizzard Warning from 8pm tonight through 8pm Wednesday. Its possible this may need to be extended, but we`ll monitor model and event trends tonight and tomorrow and make that determination. Through the day Thursday, the mid-upper level low over the Ohio Valley will gradually shift east as the surface low over lake Michigan weakens and moves southeast. Further downstream, these features will reinforce a developing nor`easter near Long Island. By Thursday evening/night, a shortwave embedded within this cyclonic flow looks to rotate out of Ontario into the Upper Great Lakes. I don`t think this will support any re-invigoration of the dwindling snow given the dry air and surface high that will be building in at the same time. From there, the pattern will support a mostly dry Friday and weekend with temps warming a little more each day. By Sunday, most of the region is expected to be in the 40s or 50s. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 749 PM EDT Tue Apr 2 2024 Deepening low pres over southern Lake MI will lift to central Lake MI tonight, then slowly weaken as it drifts sw, then to the e on Wed. Associated shield of snow will spread across Upper MI tonight with heaviest snow occurring over n central Upper MI. Strong/gusty nne winds upwards of 35-40kt will develop at all terminals, beginning tonight at SAW/CMX and Wed morning at IWD. Initial snow affecting IWD should diminish for a time tonight, resulting in IFR/LIFR improving to MVFR. Snow will increase again on Wed, dropping conditions back thru IFR to LIFR. At CMX, snow may not really pick up until Wed morning. Expect VFR to fall to MVFR tonight, then to LIFR on Wed. At SAW, expect conditions dropping thru MVFR to IFR and LIFR by late evening. For much of the overnight thru at least early aftn on Wed, SAW will likely be blo airfield landing mins due to mdt/hvy sn and blsn. Limited improvement to airfield landing mins expected late Wed aftn. && .MARINE... Issued at 307 PM EDT Tue Apr 2 2024 Tonight, winds will increase as a strong spring storm moves into the region. This storm will linger in the Great Lakes through early Thursday, resulting in a longer duration Storm Force and Gale Force wind event. This, coupled with the heavy snow, will result in visibility near zero across most of the central and eastern portions of the lake. The strongest winds near or of Storm Force are expected by early Wednesday morning and through the day, followed by gales into Thursday morning. Winds will primarily be out of the northeast and north, so the largest waves (upwards of 18 feet significant waves) are expected along the southern lakeshores of Lake Superior from the Apostles eastward, save for shelter provided in Keweenaw Bay. Winds should fall below gales Thursday morning, dropping further below 20 kts by Friday morning. These light winds look to persist through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Storm Warning from 2 AM Wednesday to 2 AM EDT Thursday for MIZ001-003. Lakeshore Flood Advisory from 8 AM EDT /7 AM CDT/ to 8 PM EDT /7 PM CDT/ Wednesday for MIZ001>003-005-006-009. Winter Storm Warning until 2 AM EDT /1 AM CDT/ Thursday for MIZ002-009-010-084. Blizzard Warning until 8 PM EDT Wednesday for MIZ004-005. Winter Storm Warning until 2 AM EDT Thursday for MIZ006. Winter Storm Warning until 2 PM EDT Wednesday for MIZ007-013- 014-085. Winter Storm Warning until 1 PM CDT Wednesday for MIZ011-012. Lake Superior... Gale Warning until 8 AM EDT /7 AM CDT/ Thursday for LSZ162. Storm Warning until 8 AM EDT /7 AM CDT/ Thursday for LSZ240>251-263>267. Lake Michigan... Gale Warning until 2 AM EDT Thursday for LMZ221-248-250. && $$ UPDATE...Rolfson SHORT TERM...Voss LONG TERM...JTP AVIATION...Rolfson MARINE...JTP
Area Forecast Discussion
National Weather Service Nashville TN
849 PM CDT Tue Apr 2 2024 ...New UPDATE... .UPDATE... Issued at 849 PM CDT Tue Apr 2 2024 Tornado Watch will expire at top of hour. Regional radar imagery showing line of convection pushing eastward, but with environment along and ahead of it worked over and 03/00Z KOHX Sounding derived indicies showing very marginal low to mid level lapse rates, which has been one of the main players in putting a "Nail in The Coffin" for robust strong to severe thunderstorm development across our area as these early evening hours have progressed, not expecting any more organized severe potential tonight. As Tornado Watch expires at top of the hour, will updated gridded forecast shortly afterwards and will do a more thorough examination of forecasted weather conditions through remainder of tonight. && .SHORT TERM... (Rest of today through Wednesday) Issued at 1104 AM CDT Tue Apr 2 2024 A dangerous setup is in place this morning for severe weather late this morning through the evening hours. A wave of showers and storms developed over eastern AR/western TN and has lifted northeast into the western part of our CWA. The atmosphere ahead of that wave is characterized by 500-1000 J/kg of mlCAPE. According to SPC Mesoanalysis West Tennessee and the northwestern third of Middle Tennessee are uncapped. So far, small hail and some strong winds have been reported in West Tennessee. Closer to Nashville, the 12z OHX raob and BNA ACARS soundings show a cap in place just above 700 mb. ACARS around 15z show that the cap has eroded away. Additional storms are expected to develop just west of the area early this afternoon as the leading edge of large scale ascent noses closer to the area. The environment ahead of that second wave will be dependent on this morning`s round. Ample shear will be in place regardless, but the amount of recovery for instability is in question over the northwestern part of the area. Further south and east, the environment will be less questionable with mlCAPE values between 1000-1500 J/kg. Storm modes could be a mix between supercells and line segments. The more recent runs of the HRRR have been holding onto the morning round a little longer which in turn has made the afternoon round more linear in nature and less cellular. This scenario would favor damaging winds and embedded rotations instead of a scenario where we have discrete cells that would favor potentially long track tornadoes, large hail, and damaging winds. The severe threat will come to a close on the plateau by 7 to 9pm. Some additional showers may continue through the rest of the evening hours before coming to an end. A trough ejecting out of Manitoba will phase with the southern stream energy from today`s event developing into a large upper low centered near Chicago Wednesday morning. A lobe of energy will rotate around the base of the upper low on Wednesday sparking showers over our area. && .LONG TERM... (Wednesday Night through next Tuesday) Issued at 1104 AM CDT Tue Apr 2 2024 The upper level low will wobble eastward on Thursday with another lobe of energy rounding the base of the trough leading to more shower chances along the northern plateau For the rest of the area, conditions will be cool and breezy once again. Temperatures Friday morning will drop into the low to mid 30s but widespread frost is not likely due to surface winds remaining 5-10 mph. By Friday, the upper low will be centered over New England with northwest flow over Middle Tennessee leading to another cool and breezy day, but it should be dry. Temperatures Friday night will drop into the upper 20s to mid 30s. Winds will be a little lighter Saturday morning leading to more widespread frost compared to the previous night. Upper level ridging will start to build into the area late on Saturday allowing temperatures to begin to rebound. By Sunday afternoon temperatures will be back in the mid 60s to lower 70s. A trough looks like it will move through the central plains late in the weekend which may bring some rain chances to our area late Sunday or on Monday. && .AVIATION... (00Z TAFS) Issued at 653 PM CDT Tue Apr 2 2024 03/00Z TAFs focused primarily thru 03/06Z per potential significant convective aviation impacts. Several admendments probable per forecasted weather element fluctuations thru 03/06Z. Current regional radar trends, addressed 1hr TEMPO groups, BNA/MQY, & 2 hr TEMPO groups, SRB/CSV, for best convection time window impacts with initial VFR ceilings/vsbys lowering to MVFR/VFR ceilings/vsbys with sfc gust 40-50kts. Sfc backing winds thru 03/06Z. Sustained sfc winds 10-20kts. VCSH thru 03/24Z. && .PRELIMINARY POINT TEMPS/POPS... Nashville 46 58 40 54 / 80 60 40 20 Clarksville 43 55 39 52 / 50 70 40 20 Crossville 40 52 34 45 / 100 60 50 50 Columbia 43 57 39 53 / 80 40 20 10 Cookeville 42 54 37 47 / 100 70 50 50 Jamestown 40 53 34 45 / 100 80 60 60 Lawrenceburg 44 57 40 53 / 90 40 20 10 Murfreesboro 43 57 38 53 / 90 60 40 20 Waverly 42 55 38 52 / 50 60 30 10 && .OHX WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE.......JB Wright SHORT TERM...Reagan LONG TERM....Reagan AVIATION.....JB Wright