####018007863#### FXUS63 KARX 071940 AFDARX Area Forecast Discussion National Weather Service La Crosse WI 140 PM CST Sun Dec 7 2025 .KEY MESSAGES... - Snow likely north of I-94 (60-80%) Monday night with up to 1" possible. - Winter storm impacts parts of northern MN/northern WI Tue night. Current track favors keeping bulk of local snow accums along/north of I-94. Severe inches possible. Considerable warming with 50-90% chance to climb above freezing south of I-94...with rain, rain-snow mix entering the picture. Keep a close eye on this period and expect adjustments to the forecast. - Much colder for 2nd half of new week. Sat trending as the coldest day with single digit highs. Periodic light snow chances. && .DISCUSSION... Issued at 140 PM CST Sun Dec 7 2025 > MONDAY/MONDAY NIGHT: light snow chances. Minor accums possible north of I-94 A couple ripples in the upper level flow look to spin across the region. First one in the morning and more weakly forced of the two. Also, time/height x-sections and forecast soundings depict mostly low level saturation to work with. Temps should be cold enough for ice in the cloud, and even some suggestion for a somewhat deep DGZ in parts. Models aren't enthused with a weakening trend as the shortwave nears the local area - less areal outlay and less qpf with the pcpn. Could just be some flurries. Will hold with low end (20%) snow chances for western locations for now - but may need to move toward scattered/widespread flurry wording eventually. Minimal/if any impacts anticipated. The second shortwave shifts west to east across northern portions of the region Monday night and models show a bit more lift and deeper saturation to work with. Greater threat for minor/light accumulations. Current track holds most of any accums north of I-94 for the local area with the NBM and HREF showing a 20-50% shot for 1". Looks reasonable. > TUESDAY: relatively mild - above freezing for most! Swath of snow across the north (a few inches of accum) while temps suggest a rain/snow mix in the south. I-94 approx delineator at this time. GEFS and EPS remain in very good agreement with driving an upper level shortwave trough from western Canada Monday night, to across the northern plains and then the upper mississippi river valley Tue night. Some small variances in timing/track/strength of the system's sfc low...but the preponderance of the models' members take the low center from northcentral MN to across central WI. Latest runs of both models also have more than 50% of their members in a slower, bit stronger solution compared to the mean - indications of the potential for a stronger system then currently depicted. Favorable isentropic upglide leads the system in with deep QG convergence as it moves through. Fgen is kind of disjointed at this time, and mostly in the lower levels. Not a great signal for enhanced banding, but still a few days out. Perhaps some upper level jet support too. Ample saturation per forecast soundings and time/height x-sections to work with. Appreciable warming on the south side of the system bring pcpn types into question. Vertical temp profiles lean into rain or snow for now - with little suggestion for "icy" to enter the mix. Will hold with snow/rain as the ptypes for now. How much? QPF NAEFS and EPS are around +1 while EFIs for snow (within the snow band) top out at 0.7 with a non 0 SoT. This is an increase in the EFIs over its past few runs. LREF near 50% for 4+ inches of snow at 10:1 ratios in the heart of the snow band. Ratios could very well be near that at the start of the event, but likely kick up into the low-mid teens overnight. NBM leans into more snow with 30-50% chances for 6+". Considering the models are showing some signs of strengthening with this system, think 6+" could be reached in heart of the deformation region, which current track keeps across northeast MN/northern WI. Still, close enough that a Winter Storm Watch might be needed for locations north of I-94 - namely Taylor and Clark counties in WI. Meanwhile, southward temp profiles suggest a mix of rain, rain-snow or snow. Much less for possible snow amounts as a result. Again, icing threat looks low at this time - but will have to keep an eye on it. Northwest flow post the system Wed, along with favorable low level lapses rates-cold air advection, are likely to kick up snow showers and/or flurries. As for how warm? 25% of the latest EPS members push 40+ degrees on the southerly flank of the winter storm. The GEFS isn't quite as warm, although a few high end outliers also like getting to 40. Both model suites have warmed a degree or two each day - so definitely a trend that bears watching. Obviously, temps will be reliant on how the system tracks - if it moves more south, so will the milder air. > REST OF THE WEEK: periodic snow chances, back into the cold. The "busy", progressive northwesterly upper level flow persists for the second half of the new week. Colder air on tap to return with Fri-Sun looking rather chilly. 75% of the GEFS and EPS members hold high temps in the single digits for Saturday - the coldest day of the bunch. Winds aren't looking particularity strong but apparent temps for Sat morning in the low to mid 20s below zero are trending. Bits of shortwave energy push near/across the upper mississippi river valley over this period, but with the expected disagreements in placement/timing/strength between the ensemble suites at this time frame. That said, no suggestion of a stronger/higher impact system. WIll hold with the model blend for pcpn chances. The following week could hold some hope for warming as a west coast ridge that the long range guidance has been tantalizing the region with might (might) finally work east and across the area. A return to normal, perhaps a bit above, temps would occur. A big IF though. Mark and place in the "wait and see" file. && .AVIATION /18Z TAFS THROUGH 18Z MONDAY/... Issued at 1144 AM CST Sun Dec 7 2025 Clear skies this afternoon fill in through this evening as north winds become light and variable ahead of low chances for snow tonight into early Monday morning. The responsible wave is driving radar returns through the Northern Plains will be on a weakening trend as it approaches the Upper Mississippi River Valley. Therefore, have not added any mention of snow with <30% confidence at either TAF site. Higher, albeit minimal, chances lie west of the Mississippi River Valley at smaller airports and KRST TAF site from 6-12Z. Will require further amendment depending on how the wave and observations continue through Minnesota this evening. Regardless of snowfall, low level moisture and warm air advection expected through Monday morning, strongest west of the Mississippi River Valley, will cause MVFR-IFR ceilings. Snowfall chances frequent the forecast area after the 07.18Z TAF period. Initially Monday night primarily north of Interstate 94 locally affecting smaller airports in central Wisconsin. Subsequent mixed precipitation chances Tuesday afternoon through Wednesday morning will affect airports area wide with rain likely in northeast Iowa to snow in central Wisconsin. Determining exact location of precipitation type and accompanying impacts will be forecast detail to monitor in coming TAFs. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Rieck AVIATION.....JAR ####018009813#### FXPQ50 PGUM 071943 AFDGUM Area Forecast Discussion National Weather Service Tiyan GU 543 AM ChST Mon Dec 8 2025 .Marianas Update... Satellite imagery shows a slight increase in cloud cover to the east of the coastal waters of the Marianas, but it looks like this increased cloud cover is a mixture of low to mid-level clouds with no notable increase in showers. With this in consideration, kept the forecast today partly sunny with isolated showers. Model guidance continues to support a extended period of dry weather, typical of region's transition to dry season. As shearline fragments shift southward from elongated frontal systems to the north, breezy conditions will be possible late this week. For the marine forecast, Ritidian Point buoy did not show the continued decline in the north to northeast swell as expected, and without additional surf observations overnight, it was difficult to support the expiration of high surf and the high risk of rip this morning, so they were extended to 4 PM this afternoon to allow for morning observations to be received and evaluated with buoy data. Combined seas of 5 to 7 feet are expected to persist, as the seasonal trade swell and secondary northeasterly swells linger. && .Eastern Micronesia Update... A dry trade-wind pattern continues across most of the region, with satellite some spotty to scattered showers and isolated thunderstorms south of Pohnpei and Kosrae, along the northern edge of the Near-Equatorial Trough (NET). Additional showers are seen along and east of the Date Line, associated with a series of troughs, and it these troughs that models show moving westward into the region, increasing the potential for showers slightly at Majuro as early as tonight and to Kosrae Tuesday night and Pohnpei around Friday. Pohnpei's buoy and satellite altimetry data support that seas are still pushing up to 10 feet at Pohnpei and Majuro so the Small Craft Advisory remains in effect through this afternoon, while seas around Kosrae are around 6 to 8 feet, below the 10 foot threshold. The mixture of an elevated northeast swell and long-period continues to support hazardous surf along north facing reefs of Pohnpei and Majuro, and north and east facing reefs of Kosrae. Both swells are expected to subside later today and should allow surf to drop below hazardous levels of 12 feet along north facing reefs of Majuro and 9 feet along north facing reefs at Pohnpei and Kosrae. There is greater uncertainty that surf will drop below 8 feet at Kosrae, which has a lower threshold than the 12 feet of Pohnpei and Majuro, so there is the potential that the High Surf Advisory will be extended for east facing reefs of Kosrae if model, altimetry and buoy data support the extension. && .Western Micronesia Update... Satellite imagery this morning shows scattered showers and isolated thunderstorms continue to develop convergent flow just north of the Near- Equatorial Trough (NET) that extends from just east of Palau to the coastal waters of Chuuk Lagoon. Based satellite trends, scattered showers and isolated thunderstorms were continued through the morning hours at Chuuk, with convection expected to develop around Palau through the day as upper-level support shifts westward. It looks like Yap Proper will be just north of the convection today, but kept the potential for scattered showers at Yap tonight. The NET is expected to shift west-southwest Tuesday, and allow a drier trade- wind pattern to settle across most of the region for most of the week. Altimetry data suggest 6 to 7 foot seas extend across Yap and Palau, while seas of 8 feet continue around Chuuk. A High Surf Advisory is still in effect for north-facing reefs of Chuuk through 5 PM ChST today due to the mixture of the long-period north swell and elevated northeast swell, with both swells expected to slowly subside this evening. The north swell continues to diminishing near Palau and Yap, so the High Surf Advisory and Coastal Flood Statement at Yap was allowed to expire this morning. Seas should decrease slightly across the region toward the end of this week as background trade swell and north swells relax. Winds will remain light to moderate for Palau and Yap throughout the forecast period, with mostly moderate trade winds expected for Chuuk through at least Tuesday before diminishing in the latter half of the week. && .Prev discussion... /issued 612 PM ChST Sun Dec 7 2025/ Marianas Synopsis... Gentle to moderate northeasterlies prevail across the region tonight. Satellite imagery and Doppler radar indicate light passing showers in Guam and Rota waters. Buoys show seas are about 5 to 6 feet. Discussion... A minor surface trough is expected to bring low-end scattered showers to the Marianas near midnight tonight, followed by an extensive period of drier weather for much of the forecast period. As shearline fragments shift southward from elongated frontal systems to the north, this will bring breezy conditions late this week. Marine... Significant northerly swells generated by distant synoptic systems continue to produce hazardous surf and a high risk of rip currents along north facing reefs of the Marianas through at least late tonight. Surf is then likely to fall below hazardous levels thereafter as this pulse in northerly swell diminishes, which will also allow rip current risk to drop to moderate along said reefs. Combined seas of 5 to 7 feet are expected to persist, as the seasonal trade swell and secondary northeasterly swells linger. Eastern Micronesia... The main forecast challenge was in determining when to end headlines. The Pohnpei buoy checked in with 9.91 feet and a recent increase in both sea and swell heights. Majuro is also still seeing the effects of the trade-wind surge to the north, with an added concern of another peak in the King Tides later this evening/first half of the night, before they start to subside. As such, left the Coastal Flood Advisory going through tonight at Majuro, while extending the Small Craft Advisory for Pohnpei and Majuro, which now expires at 3 PM Monday (coinciding with the High Surf Advisory expiration). As for rainfall potential, Pohnpei looks to remain mostly dry with just isolated showers through Thursday. Meanwhile, a remnant shear line will keep scattered showers going at Kosrae through the next 12 hours, becoming isolated Monday. Then, an approaching surface trough will increase showers by Tuesday at Majuro and Tuesday night for Kosrae, with scattered showers going at both locations through the end of the week. This feature could also increase rainfall potential at Pohnpei by Friday. Western Micronesia... Satellite this afternoon continues to show a fairly dry regime across much of western Micronesia. Scattered showers are building in across Chuuk along the axis of a shallow trough which is propagating westward through the area. Meanwhile, an area of scattered showers and isolated thunderstorms is seen over and southwest of Sorol in Yap State, while dry conditions persist for Yap Proper and Palau. This area of showers is located along a weak embedded trough north of the Near-Equatorial Trough (NET) axis, which has shifted further south of the area over the last day. Strong easterly winds and divergence aloft have been supporting thunderstorms in this area east to southeast of Palau and Yap throughout the day, but models show this upper-level support moving away west of the area tonight. The area of surface troughing looks to shift gradually west-southwest and increase showers near Palau and Yap Monday and Monday night, but models keep most of the showers to the east and south of coastal waters. Chuuk will see scattered showers tonight and Monday as the surface trough moves through. Thereafter, a dry trade-wind pattern looks to remain steady through the end of the week with mostly isolated showers across the region. Altimetry data shows 6 to 8 foot seas across much of the region near and north of Yap and Palau, with 9 foot seas seen to the northeast of Chuuk. A High Surf Advisory is in effect for north-facing reefs of Chuuk through 5 PM ChST Monday as a pulse of elevated long-period north swell moves through the region, combined with the elevated trade swell. North swell is diminishing further west near Palau and Yap, but will support hazardous surf up to 9 feet for north-facing reefs of Yap through late tonight. For Palau, the High Surf Advisory and Coastal Flood Statement expired this afternoon as high King tides and north swell continue to diminish. Seas should decrease slightly across the region toward the end of this week as background trade swell and north swells relax. Winds will remain light to moderate for Palau and Yap throughout the forecast period, with mostly moderate trade winds expected for Chuuk through at least Tuesday before diminishing in the latter half of the week. && .GUM WATCHES/WARNINGS/ADVISORIES... GU...High Rip Current Risk until 4 PM ChST this afternoon for GUZ001. High Surf Advisory until 4 PM ChST this afternoon for GUZ001. MP...High Rip Current Risk until 4 PM ChST this afternoon for MPZ001>003. High Surf Advisory until 4 PM ChST this afternoon for MPZ001>003. Marianas Waters...None. && $$ Marianas/East and West Micronesia Update: Schank Marianas: Montvila Eastern Micronesia: Doll Western Micronesia: DeCou