Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/23/25


Area Forecast Discussion
National Weather Service La Crosse WI
608 PM CST Wed Jan 22 2025 .KEY MESSAGES... - Off and on flurries/snow showers will continue into the overnight hours. Minimal additional accumulations are expected, however visibilities could be reduced for a time with the cold front medium probabilities ((30-60%) for visibilities under 1 mile this evening. - Temperatures fluctuate over the next few days with highs in the teens for Thursday and moderating into the 20s and 30s to start the weekend (60 to 100% probability that temperatures remain below 30 deg F through Friday). - Light snow showers again possible Friday through Saturday night, 40 to 80% for measurable (0.1" or more) with higher probabilities north of I94. && .DISCUSSION... Issued at 242 PM CST Wed Jan 22 2025 Rest of Today - Tonight: Scattered Flurries and Snow Showers: Current water vapor imagery and 22.18z RAP 500mb heights depict a shortwave trough with a cold frontal boundary across north-central Minnesota. Further southwest, a secondary wave and vorticity lobe is aiding the instigation of precipitation across southern portions of the area in southwestern WI and northeast IA. As this wave continues to pivot east, thinking this initial axis of precipitation will slowly shift east of the local area over the rest of the afternoon and into the evening. Attention then turns towards the aforementioned cold front as it sweeps through the area this evening. Fairly solid agreement amongst the CAMs that low-level frontogenesis and steeper 0-2km lapse rates will instigate a broken line of snow showers. While minimal accumulations are anticipated with these, brief visibility reductions to a mile or lower may be possible as indicated in the 22.12z HREF with medium probabilities (30-60%) for visibilities under 1 mile this evening with some increase in wind gusts to 20-30 mph behind the front. Given their remains some steeper low-level lapse rates into the overnight hours in the recent RAP/HRRR, held onto some flurries through midnight where this environment is more favorable east of the Mississippi River. Tomorrow: Briefly Cooling Down: As we head towards sunrise tomorrow, the aforementioned trough axis moves overhead with 850mb temperatures of -17C to -19C overhead in the 22.15z RAP. As a result, guidance continues to reflect overnight lows falling below normal with the median low temperatures in the national blend in the single digits, perhaps some areas below zero in southeast MN and north-central WI with lingering cloud cover posing some questions as to how far we will drop. With some breezy winds still in place behind the front, wind chills will bottom out in the teens to around 20 below zero overnight, outside of advisory criteria but will still feel unpleasant. As high pressure moves into the region for late morning and afternoon, expecting clouds to diminish albeit still remaining colder than normal with highs generally in the upper single digits to teens for the afternoon on Thursday. Below normal through Friday with moderation into the weekend. Light snow showers possible for parts of the area Friday through Saturday night: Thursday night, a large area of cold high pressure is forecast to be over the region with -20 deg C 850mb isotherm stretching from the U.P. of Michigan into Ontario and Quebec Canada. The thermal trough shifts to the east with light northwest surface flow becoming southwest, then westerly into Saturday. Some moderation in temperatures is forecast for Friday, however the westerly winds Saturday should boost readings to above normal levels for the weekend. Normals are still in the 20s for highs and single digits for lows. Once again, a broad trough aloft with drag a cold front through the area. Depending on the thermal/moisture/lift fields, some light snow may try to develop over parts of the forecast area Friday afternoon into Friday and then with the cold front later Saturday afternoon into Saturday night. The organized light snow is currently forecast north of the forecast area, however with the push warm air advection followed by the cold air, some flurries or snow showers could extend southwestward into the forecast area. We have added snow chances to this period, however as we refine the timing, the POPs will likely increase. Relatively warmer air is already moving in Saturday night and Sunday, thus seasonable temperatures are forecast. We`ll need to monitor this wave as the 22.12Z NAM snow squall parameter was highlighting some steep lapse rates over the area with low values of CAPE Saturday afternoon. Although the broad trough over Canada expand Sunday into Monday, we are far enough to the west where a more westerly/relatively milder airflow is expected and the storm track remains over the Upper Great Lakes region. Above normal highs in the 20s and 30s for Monday and Tuesday continue to warm with 30s to around 40 possible for Wednesday. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 608 PM CST Wed Jan 22 2025 A low VFR stratus deck is currently situated over the area. MVFR CIGS are expected to move into the area along with a band of snow showers. These snow showers are expected to exit the area by midnight. Brief reductions in visibility will be possible, mainly in the 1 to 3SM range, with regards to this band of snow. Guidance continues to suggest that the low stratus deck continues into Thursday morning however, with potential for MVFR CIGS to come in and out. By Thursday mid-morning skies are expected to clear out. Southerly winds will transition to northwest winds as a cold front moves into the area. These northwest winds will be with us through the TAF period. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Naylor/Zapotocny AVIATION...Cecava
Area Forecast Discussion
National Weather Service Des Moines IA
549 PM CST Wed Jan 22 2025 ...Updated for the 00z Aviation Discussion... .KEY MESSAGES... - Snow showers continue this afternoon and evening, primarily across the southeast and east. Accumulations will be light and generally less than a 1/2 inch. - Front moves through later tonight with some flurries possible. Winds may be gusty behind the front as wind chills reach the -15 to -20F range early Thursday morning. - After a brief period of cold Thursday, temperatures moderate for the weekend, with a warm up expected for the start of next week. Little if any chances for precipitation exist during this period. && .DISCUSSION... Issued at 240 PM CST Wed Jan 22 2025 On and off snow showers have continued this afternoon as an associated mid level shortwave moves to the east. The base of this wave is seen just starting to enter western Iowa per RAP analysis. As the wave moves eastward, kinematic fields continue to signal convergence overspreading across eastern portions of state. Forecast soundings also clearly show saturation within the DGZ continuing this afternoon and evening across this area. This will aid in sustaining snow showers across portions of our southern and eastern CWA this afternoon into the evening hours. Regarding snowfall amounts, the majority of deterministic guidance shows generally less than a 1/2 inch, but across the far southeast/east, there may be locally higher amounts closer to an inch where QPF is higher. Short term ensemble guidance is in good agreement with amounts generally less than a half inch areawide, while some ensemble members (<10% of members) show locally higher amounts of 1/2 to 1 inch possible across the far southeast and east. Highs today will be in the low 30s, but across the far southeast may see highs read slightly higher than NBM guidance as evidenced by observations, so have tried to raise highs in that area to account for this. Snow showers should push off to the east tonight as the upper level wave moves eastward. A frontal boundary emanating from a surface low over the Great Lakes will push through later this evening/overnight as the shortwave departs. Some flurries associated with this frontal passage are possible with BUFKIT soundings showing some saturation in the dendritic growth zone. Any accumulations associated with the frontal passage should be light. Winds may gust up to 25 kts behind the front, primarily across the north as cold air begins to filter in behind the front. This will result in wind chill values Thursday morning in the -15 to -20F range. While not in criteria range, those who plan to be outdoors tomorrow should dress warmly. Thursday will see another upper level wave drop southward from the ND/SD area, but with the lack of moisture evident, only expecting some mid to high level cloudiness with this feature as highs reach the mid to upper teens. This spell of cold is short lived, as by Thursday evening warm air advection returns as a surface high across SD/NE departs the area. Friday into Saturday will see more of a zonal flow pattern set up across the state despite an upper level shortwave moving across Minnesota. This results in little appreciable PoPs across the area for the weekend. A thermal ridge will begin building into the Northern Plains by Sunday evening as a cut off low develops over the Southwest US. The advancement of the ridge eastward will result in warming temperatures and little to no chances for precipitation as depicted by the latest NBM guidance. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 549 PM CST Wed Jan 22 2025 The initial round of snow is pushing across central to southern Iowa MVFR ceiling and visibility impacts at sites KDSM/KOTM lasting another couple hours. Meanwhile, a secondary push associated with the cold front will bring a secondary lowering of ceilings back to MVFR along with breezy northwest winds gusting 20-25 kts. Patchy light snow is also possible with this secondary push, however confidence in occurrence is lower with current expectations keeping that round west of TAF sites. Amendments will be made through the evening as the evolution becomes more certain. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Castillo AVIATION...Hagenhoff
Area Forecast Discussion
National Weather Service Louisville KY
635 PM EST Wed Jan 22 2025 .KEY MESSAGES... * Spotty flurries Thursday into Friday with moderating temperatures towards the weekend. A mix of rain and snow is possible on Sunday night, but forecast confidence remains low. && .SHORT TERM /THROUGH THURSDAY/... Issued at 316 PM EST Wed Jan 22 2025 Tonight, near the axis of an upper trough and between a surface low centered over the Great Lakes and high pressure along the East Coast, the Lower Ohio Valley will see warm air advection continue through the night. Some mid-level cloud cover is expected to move over the CWA early in the night before skies clear for most of the night. This clearing is a negative for temperatures as radiative cooling will begin, but the 5-10 mph southern winds with some 15 mph gusts will limit falling temperatures to the teens. This is still cold, but it`s still around 15 degrees warmer than last night. Tomorrow, a large upper trough drops south through the Rockies before cutting to the east over the Gulf Coast States and off the Mid-Atlantic. This will push a shortwave/weak cold front, extending south of the aforementioned surface low over the Great Lakes, through the Ohio Valley. Limited early warm air advection in the day will help get temperatures into the 30s across southern Indiana and central Kentucky. During the afternoon/evening hours, as the cold front drops southeast through the region, flurries and/or light snow showers are expected to pass from west to east through the CWA. Also, expect winds to begin veering towards the northwest behind the front to usher in the next round of cold air advection. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Issued at 316 PM EST Wed Jan 22 2025 Thursday Night through Saturday Night... A shortwave trough axis is forecast to push through the region Thursday night and early Friday. The global models here remain quite dry, but the high resolution HRRR suggests that at least scattered snow flurries and perhaps some isolated snow showers may develop here. Some very minor accumulations could occur Thursday night with a coating to perhaps a quarter of an inch in spots. Lows Thursday night will be cold with readings in the upper single digits across southern IN and northern KY with mid-upper teens across southern KY. Friday may start off with some lingering flurries in the morning with drier conditions in the afternoon as the upper trough axis pushes east. Highs on Friday look to warm into the upper 20s over southern IN and northern KY with highs in the upper 20s to the lower 30s over southern KY. Lows Friday night will be in the upper single digits to lower teens over the Bluegrass region. Elsewhere, lows of 15-20 are expected. A southerly flow will get re-established on Saturday with milder temperatures expected. Highs will range from the lower 40s across southern IN and into northern KY. Across southern KY, highs of 44 to 49 look likely. Lows Saturday night will drop back into the 25-30 range. Sunday through Wednesday... Still will need to watch the Sunday-Monday time frame for the potential for some mixed wintry weather. Previous model solutions showed a plume of moisture coming up ahead on approaching upper wave coming in from the Plains. The GFS was more aggressive here with the Euro/Canadian being more suppressed with the system. This afternoon`s model runs were similar in the Canadian/Euro camps with keeping the system well to our south. However, the GFS remains on the north side of the guidance envelope with some light rain/snow across portions of southern KY. Overall, ensemble spread here remains quite high, so forecast confidence remains low. If moisture can get further north into KY, snow would be possible over southern IN/northern KY with more of a cold rain across southern KY. For now, will keep some low chance PoPs over the southern areas and continue to monitor over the next few days. Highs Sunday will likely warm into the lower 40s with overnight lows in the middle 20s. For Monday through Wednesday, a split flow pattern looks to develop across the CONUS with a deep cutoff low over the southwestern US and downstream confluent flow from the MS Valley eastward through the Mid-Atlantic. Eventually this upper low over the SW will eject out and come into the eastern US by mid-late week. Highs Monday will be in the lower 40s with overnight lows in the upper 20s. Milder readings are expected Tuesday and Wednesday with highs in the upper 40s to near 50 and overnight lows in the upper 20s to the lower 30s. && .AVIATION /00Z TAFS THROUGH 06Z FRIDAY/... Issued at 635 PM EST Wed Jan 22 2025 VFR conditions expected tonight through roughly midday Thursday. Light winds tonight from the south, with only SDF maintaining 6 kt or more. There`s a narrow window of opportunity just before sunrise for marginal LLWS, mainly at SDF and HNB with a low- level jet from the WSW. However it`s short-lived and confidence is fairly low, so will not include it in the TAFs. Ceilings lower in the afternoon with all but BWG dropping into MVFR as a weak boundary moves into the area. Can`t rule out a flurry here or there, but probabilities are fairly low and restrictions to cig/vis are unlikely. Winds will pick up from the west at 10-12 kt with gusts near 20 kt possible. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...None. IN...None. && $$ SHORT TERM...KDW LONG TERM...MJ AVIATION...RAS
Area Forecast Discussion
National Weather Service Marquette MI
627 PM EST Wed Jan 22 2025 .KEY MESSAGES... - Lake effect snow into Thursday morning to bring generally 1-4 inches of fluffy snow to the north-northwest wind snow belts, but locally 4 to 6 inches in the vicinity of the Marquette/Alger county line. - Moderating airmass will see temperatures trending more or less towards normal values from midweek onwards. - Passing clipper systems will bring in rounds of light lake effect/enhanced snow through the extended period, but widespread significant snowfall is not expected. && .SHORT TERM /THROUGH TONIGHT/... Issued at 408 PM EST Wed Jan 22 2025 Water vapor imagery and RAP analysis show mid-level troffing dominating central and eastern N America. Within the trof, a shortwave over ne MN and adjacent Ontario is beginning to move out over Lake Superior. At the sfc, associated ill-defined low pres is located btwn Isle Royale and the Keweenaw along cold front extending from near the Slate Islands in northern Lake Superior to near Saxon Harbor. Canadian radar near Thunder Bay has been showing a band of hvy lake effect snow along the cold front to the se and e of Isle Royale. Ahead of the shortwave, areas of -sn have been spreading across Upper MI today. A mid-lake convergent LES band in the sw flow up Lake MI early today just brushed the se corner of Luce County. That hvy snow band has moved eastward and is now streaming onshore btwn Naubinway and the Mackinac Bridge. Current temps across the area range mostly btwn 10 and 15F. As aforementioned shortwave continues to drop se tonight, cold front will do the same. The ill-defined sfc low along the front is likely to become much better defined over the water given the heat/moisture fluxes off the lake due to the cold air moving overhead (850mb temps of -15 to -20C). The exact evolution of the the low/circulation is uncertain. While consensus is for the low to track down toward somewhere btwn Grand Marais and Whitefish Pt, some of the guidance, HRRR/WRF-ARW in particular, trail a sharpening sfc trof westward and almost a secondary circulation that moves onshore in western Alger County. This results in winds veering more northerly in that area, even well w into Marquette County per ARW. There is very low confidence in that playing out, but the consensus overall is for a NNW wind to develop as the sfc low moves onshore to the e, ideal for heavier LES to develop vcnty of the Marquette County/Alger County line. This occurs due to slightly backed winds off of Marquette County enhancing a convergence zone offshore that streams into that area. NAM fcst soundings indicate inversion on the lower side around 5kft, but the HRRR is up to 6 to maybe 8kft. Even with the lower inversion height, the DGZ will be well positioned in the convective layer to fluff up snow accumulations with a high SLR. Opted to issue winter wx advy for Marquette/Alger counties, but that`s largely for the area btwn Marquette and Au Train southward in the vcnty of the Marquette/Alger County line for the potential of 4-6 inches of snow late tonight thru Thu morning, impacting the morning commute. A period of hvy snow will occur closer to where the sfc low moves onshore farther e, but it is anticipated to be short-lived since the convergence owing to the low is short-lived around the time of landfall. Nonetheless, will be something to monitor for potential inclusion of Luce County/northern Schoolcraft County in advy. Winds will be gusty to 30 mph or so near the shore late tonight and early Thu morning, so there will blsn as well. To the w, inversion is lower than to the e and it gradually lowers thru the night. DGZ does slowly fall blo the ideal position in the convective layer, so SLRs should gradually decrease during the night. Still, it will be fluffy snow, leading to less impacts for travel. From late this aftn to sunrise on Thu, expect 1-3 inches in general, except 2-4 to isold 5 inches in the high terrain. Temps will fall to 0 to 10F above by sunrise, coldest interior w. In those coldest areas, wind chills will fall to -10 to -15. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Issued at 224 PM EST Wed Jan 22 2025 Anomalously strong ridging setting up over the northeast Pacific/Gulf of Alaska on Friday with 500 mb height rises of 360 m or more will gradually weaken through the weekend into early next week as the ridge moves ever slowly toward western Canada. This mid- upper level ridging will promote downstream troughing across the northeast portion of North America through most of next week. The end result will be a nw flow into the Upper Great Lakes between these large scale features with a series of mainly weak Clipper shortwaves moving through the region from late this week into next week. Any system snow with these shortwaves looks to be light until at least maybe mid to late next week. However, forcing from these shortwaves along with associated shots of cold advection will support bouts of light to at times moderate lake effect snow over mainly the NW to W snow belts through the extended forecast period. Temperatures will gradually trend warmer for the most part, from below normal late this week, to near normal this weekend into early next week, to above normal by the middle of next week. Beginning Thursday, cold advection in the wake of this afternoon/tonight`s Clipper system will support NW flow LES through Thursday night. Although model soundings have inversion heights abruptly lowering to near 3 kft west and 4-5 kft east as sfc ridging quickly advances from the Northern Plains, much of the cloud layer beneath the inversion is within the DGZ which should yield another fluffy 1-2in of snow, locally higher up to 2-4in in the eastern UP with a longer fetch off of Superior. Clearing skies and light winds Thu night under the sfc ridge will promote ideal radiational cooling conditions and min temps on the lower end of forecast guidance. Decided to lean a bit toward the cooler and usually better performing biased-corrected Canadian guidance which suggest the potential for min temps of -10 to -15F over the western interior and a few -10F or colder readings over the typical cold interior central locations as well. After a dry, cool and breezy Friday, the next round of clipper shortwaves arrive Friday night into Saturday bringing light snow to mainly northern portions of the cwa with maybe some weak lake enhancement from the shortwaves bringing perhaps a period of moderate snow into the Keweenaw on Saturday. CAA with 850 mb temps dipping near -20F will support a brief period of light to at times moderate NW flow behind the Clipper on Sat night. A brief period of weak ridging should result in drier conditions Sunday, before the next series of clipper shortwaves move through early to middle of next week. Guidance continues to keep the strongest shortwave energy mainly northeast of Lake Superior, so have continue to limit PoPs to the northern UP, greatest in the northeast UP where NW flow may lead to some lake enhancement. Operational GFS and Euro continue to show stronger shortwave action dropping through sometime in the Wed-Thurs time period, with below normal temps and NW flow LES behind it for the end of next week. There are significant timing differences, however, and these solutions run somewhat counter to the current GFS and ECMWF ensemble means which aren`t quite as strong, and also have mid-upper level ridging moving into the Upper Great Lakes for the end of the week. This would suggest warmer than normal temps and drier conditions at that time. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 626 PM EST Wed Jan 22 2025 Low pressure over Lake Superior will transit the region tonight, which will help support lake effect snow showers developing and pressing into all terminals tonight. Expecting showers to yield mainly MVFR ceilings and MVFR visibilities, expect at KCMX which can expect IFR visibilities. Additionally, gusty northwest winds of 20- 30kts are expected, highest at KCMX tonight. Increasing dry air will leading to improving conditions by mid-late afternoon Thursday for all terminals, although MVFR ceilings should linger at KCMX/KIWD. && .MARINE... Issued at 224 PM EST Wed Jan 22 2025 A clipper low is tracking across northern Lake Superior this afternoon, with SW winds out ahead of it across eastern Lake Superior veering to the NW across the western half of the lake. Wind gusts up to 20-30kts continue this afternoon, but a few NW gale- force gusts to 35kts will be possible across the central portions of the lake tonight. Confidence remains too low to warrant a headline. As high pressure influences the forecast for Thursday, winds slowly backing westerly around 20-25 kt are expected. For Friday into the weekend, primarily southwest to west winds of 25-30 kts are expected but there could be brief periods of gale gusts to 35 knots at times, especially late Saturday into early Sunday (around 40-70% chance) as winds shift to the NW again behind a passing clipper system. W-NW winds remain elevated at around 20-30kts into early next week with again a potential for gale gusts to 35 kts at times behind yet another clipper. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory from midnight tonight to noon EST Thursday for MIZ005-006. Lake Superior... Heavy Freezing Spray Warning until 7 AM EST Thursday for LSZ243>245-248-264-265. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...LC AVIATION...JTP MARINE...LC
Area Forecast Discussion
National Weather Service Springfield MO
512 PM CST Wed Jan 22 2025 .KEY MESSAGES... - Areas of flurries this evening into Thursday morning. Low chance (10-30%) of a light dusting across central Missouri and the eastern Ozarks. - There is a 20% chance of precipitation across far southern Missouri this weekend. Confidence in precip type, amounts, or impacts is low. - High confidence in daily afternoon temperatures reaching above freezing areawide Saturday into next week. && .SHORT TERM /THROUGH THURSDAY/... Issued at 124 PM CST Wed Jan 22 2025 A few high clouds have moved across southern Missouri this afternoon; otherwise, dry conditions have prevailed with 20-25 degree dew point depressions common across the region. Gusty southwest winds will decrease this evening into the overnight as mixing subsides and the surface pressure gradient lessens. Overnight lows will likely remain near or just above 20F for many, particularly for locations where greater cloud cover moves overhead. There is some signal for a few flurries this evening through Thursday morning with a pair of weak frontal passages. While RAP data show only modest lift, there could be just enough moisture to wring out a few snowflakes, particularly across central Missouri and the eastern Ozarks. To that end, a few HREF members even show low chances (10-30%) of a dusting roughly from Conway to Rolla. Farther south (generally south of I-44), temperatures are forecast to climb above freezing in the afternoon. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... Issued at 124 PM CST Wed Jan 22 2025 An upper-level wave will pass through the Mississippi Valley region early Friday, which will set up an east-to-west temperature gradient across the CWA. Temperatures look to warm into the 40s generally west of Highway 65 and only the 30s to the east. Continued warm air advection will briefly push temperatures near to above normal on Saturday areawide before another cold front brings conditions closer back to average Sunday and Monday. This weekend, ensemble guidance shows strong agreement in developing a zonal pattern aloft across much of the eastern CONUS. Global models are still hanging onto low-end precipitation chances across southern Missouri on Sunday as Gulf moisture tries to advect northward. Cluster analysis reveals important differences in the character of the 850 mb flow, however, which will have implications on sensible weather for our CWA. ECMWF and Canadian ensembles tend to favor a more southerly solution, veering the low-level jet farther south and limiting moisture return across southern Missouri. This is currently the most likely solution. GEFS members, however, tend to develop a more robust and persistent low-level jet, which would increase precipitation chances for our area. If precipitation does occur, precipitation type remains unclear as time of day will affect temperatures. Overall, PoPs remain low (20% or less). Ensembles generally show mid-level ridging amplifying across the region early next week, which would allow for the return of above-normal temperatures. NBM percentile data support highs in the upper 40s to mid 50s Tuesday and Wednesday. Additional rain chances also arrive on Wednesday with the return of southwesterly flow. This is the point when ensemble solutions begin to diverge significantly, however, so confidence in any details is low. Thus, we have stuck with NBM PoPs of 20-30% for now. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 507 PM CST Wed Jan 22 2025 VFR conditions through the period. Some high clouds are filtering through associated with a frontal passage that will be mostly dry with some light snow flurries in the northeast of our area toward central Missouri. Winds will shift more northwesterly through the period and increase in speed, but will not exceed 15 kts sustained. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...None. MO...None. && $$ SHORT TERM...Didio LONG TERM...Didio AVIATION...Nelson