Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/09/25


Area Forecast Discussion
National Weather Service Bismarck ND
900 PM CST Wed Jan 8 2025 .KEY MESSAGES... - Light precipitation is expected across western and central North Dakota tonight through early Thursday morning. A mix of snow, rain, and freezing rain is possible along the leading edge of the system, with a transition to all snow. - Breezy to windy conditions are also expected through Thursday afternoon, which could create patchy blowing snow. - There is a 60 to 80 percent chance of accumulating snow across western and central North Dakota Friday night into Sunday, with low to medium chances of at least 3 inches. - Temperatures are favored to fluctuate between below and above normal through next week, with Monday likely to be the coldest day. && .UPDATE... Issued at 900 PM CST Wed Jan 8 2025 Weak to moderate reflectivities continue to cross across western North Dakota at the time of this update, with the most consistent precipitation found across the northwest. Much of this precipitation is falling as light snow, though a few pockets of rain/freezing rain has been observed this evening, most notably around Williston. A general transition to all snow is still expected as we approach the early overnight period. Have adjusted PoPs slightly to account for more long- lasting precipitation across the north. Otherwise, the forecast remains largely on track. UPDATE Issued at 535 PM CST Wed Jan 8 2025 Low level clouds and precipitation are beginning to move into western North Dakota this evening, with the occasional rain drop evident on NDDOT cameras in the northwest. At the same time, however, light snow is beginning to be reported just over the International Border at Estevan, Canada, which does show the quicker transition to all snow posited by the most recent model runs appears to be panning out. With a mix of precipitation types still possible as we continue to cool through the evening, we will continue to monitor this trend. Overall, the forecast remains on track at this time. && .DISCUSSION... Issued at 132 PM CST Wed Jan 8 2025 Low pressure situated over the central Canadian Provinces with a trough into the Northern Plains will track southeast bringing warmer temperatures to the forecast area late this afternoon and this evening. A shortwave tracking through the northern Rockies is producing light rain over portions of northeast Montana this afternoon. This precipitation is expected to move into western North Dakota late this afternoon/early this evening and track southeast across the forecast area through the night and exit the James River Valley Thursday morning or early Thursday afternoon. Precipitation this afternoon is expected to be very light and may result in mainly virga or sprinkles. Temperatures this afternoon, south of the Big Lake are already mostly above freezing, and those north of the Lake may climb above freezing as well, so any impacts this afternoon are expected to be negligible. This evening, as the shortwave moves into eastern MT, precipitation chances will increase across western and into central ND. As atmospheric column cools, precipitation is expected to become all snow. However, prior to this occurring, there may be period where we could see, rain, and/or freezing rain, or a mix of rain/freezing rain and snow before this transition is complete. The 12 UTC model suite and cams through the day have lessened the precipitation potential across the northwest and especially the north central, but kept the high potential over the west central into southwest ND. NBM qpf is maximized over far west central ND, say around Trotters and Beach and south into far southwest. Elsewhere qpf amounts are generally less than a tenth of an inch, with lightest amounts in the north central. Snow amounts have backed off, with a half inch or less along and north of the Highway 200 corridor, and a half inch to an inch south of the Highway 200 corridor. There may be some areas (Beach to Trotters) that see 1 to 2 inches but currently it looks like only a few areas will see over an inch, with most area seeing an inch or less. There remains the potential for freezing rain, and rain with this system this evening, before the transition to all snow. With the shift in the heavier qpf more to the west central and southwest, think there may be an increase in freezing rain potential over the southwest, compared to yesterday and this morning. The main question, is whether or not surface temperatures drop back below freezing before precipitation transitions to snow. To account for this, we kept a slight chance of freezing rain over the southwest from mid to late evening. If surface temperatures remain above freezing, we should see a transition from rain to snow. If they would happen to drop below freezing, then the freezing rain potential would increase. Local research indicates that with light qpf amounts (under a tenth of an inch) with a substantial warm layer aloft, you don`t always see the wet-bulb effect and you can get a surprise freezing rain event. The light qpf would fit with this event for many areas south of the Lake, but I wouldn`t call this a substantial warm layer aloft, with a max of around 2.5 degrees above freezing. Some of the later HRRR soundings are showing quite a bit of warm air near the surface, and although there is a nose of warm air aloft, the column cools from top to bottom, yielding more of a traditional rain to snow transition. If that turns out to be the case we`re golden. If not, we could see at least a small chance of freezing rain mid to late evening. Therefore we will keep a slight chance mention this evening. It will be breezy to at times windy tonight and there could be some patchy blowing snow. However, the warmer temperatures west and south central should help diminish this threat. This can be seen in the blowing snow grids with a good portion of the southwest not seeing any blowing snow, due to today`s warm-up. For the most part, expect precipitation to be all snow after midnight, and into Thursday morning. There are some indications that we could see a loss of ice on the back side of the system with the potential for some patchy freezing drizzle. However, confidence in this is too low to mention and with the warmer temperatures, impacts would appear to be minimal at this time. Breezy to windy conditions are expected to continue through the day on Thursday, with some steep lapse rates over the area Thursday afternoon. There is some hint of some afternoon/evening snow showers, and in areas around the Turtle Mountains into the northern JRV, there may be enough loose snow for some blowing snow Thursday afternoon/early evening. In coord with Grand Forks, we added a slight chance of snow showers Thursday afternoon/evening. The RAP does show some weak instability but currently, the snow squall parameter is maximized over far southeast ND, and southeast MT into northeast WY. Will continue to monitor though. We get a short break in the precipitation Friday, but the next system is already beginning to move into the west by Friday evening. This system is a combination of a Canadian clipper system and West Coast trough that combine over the Northern Plains. There are indications that the Pacific wave may take more of a southern track, thus the overall snow totals have diminished a little with generally low to medium chances of 2 or more inches of snow through the late Friday through Sunday timeframe. && .AVIATION /00Z TAFS THROUGH 00Z THURSDAY/... Issued at 900 PM CST Wed Jan 8 2025 Mainly VFR ceilings and visibility are found across all terminals to begin the 00Z TAF period. Chances for precipitation will increase from west to east through this evening, before diminishing also from west to east late tonight. This precipitation is expected to fall primarily as light snow, though could be mixing in with some freezing rain (northwest) or rain (southwest) through this evening. A general transition to all snow is expected by late this evening. MVFR to IFR ceilings and visibility is expected to accompany this snowfall, with these lowered ceilings lingering across the forecast area though much of the period. Some wrap-around precipitation, again falling as light snow, is possible across portions of central North Dakota Thursday afternoon, though confidence is too low to include at any given TAF site at this time. The passage of a cold front tonight is expected to induce a wind shift to the northwest, becoming gusty with speeds from 20 knots and gusts up to 30 knots possible through the end of the TAF period. && .BIS WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Adam DISCUSSION...TWH AVIATION...Adam
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
558 PM CST Wed Jan 8 2025 ...New AVIATION... .SHORT TERM... (Now through Thursday night) Issued at 151 PM CST Wed Jan 8 2025 The short term forecast for Deep South Texas will feature well below normal temperatures, breezy north winds, periods of light rain and/or drizzle, and adverse beach/marine conditions. Although some light rain/drizzle has developed over the immediate coast today, most of Deep South Texas has remained rain-free due to the overall lack of moisture content present. Still, persistent low level southerly flow (~850mb) has maintained overcast skies as warm, Gulf moisture overruns the significantly cooler airmass at the surface. Meanwhile, the latest surface observations and RAP guidance reveal a tightening pressure gradient in response to a deepening coastal trough along the Lower Texas and Northern Mexico coast, which is expected to develop into a coastal low late tonight into Thursday morning. We should begin to see an increase in precipitable water after midnight tonight as the coastal low develops, ranging from 1.2 inches across the Northern Ranchlands to upwards of 1.5 inches closer to the immediate coast. This should result in an uptick in precipitation coverage for portions of Deep South Texas tonight. The latest suite of high res guidance indicates the highest rain chances (~60-80%) will reside mainly across Cameron, Willacy, and southern Hidalgo counties, as well as along the immediate coast, which coincides with the placement of the highest moisture content and proximity to the coastal low. The combination of overcast skies, brisk north winds, and increasing rain chances will result in another chilly night, with lows ranging from the mid to upper 30s across most of Deep South Texas, and closer to the low to mid 40s across the Lower RGV and the Lower Texas beaches. In combination with breezy winds, "feels like" temperatures tomorrow morning will be in the low to mid 30s region wide. The coastal low is expected to track northward along the Lower Texas Coast on Thursday, which should maintain northerly winds, overcast skies, and continued precipitation chances through the day. High temperatures will be similar to today, ranging from the low to mid 40s across the Northern Ranchlands to upper 40s across the Rio Grande Valley. The latest suite of high res guidance does indicate we should see a decrease in precipitation chances across the Rio Grande Valley Thursday afternoon as the coastal low tracks northward. However, rain chances will return region wide once again Thursday night as large scale forcing associated with an upper level trough/low, currently centered over the Desert Southwest, translates east and northeast and interacts with favorable moisture content. With temperatures expected to remain above freezing Thursday night, winter precipitation is not expected at this time. Otherwise, a high risk of rip currents due to increased winds and seas will continue across the Lower Texas beaches. && .LONG TERM... (Friday through next Wednesday) Issued at 151 PM CST Wed Jan 8 2025 Key Messages: -Below normal temperatures expected through the long term. -Rain chances taper off for the weekend but return for the workweek. The long term period will begin with an upper level trough digging into northern Mexico and moving through Deep South Texas on Saturday while a surface low continues to move eastward into the SE US. As this low pushes eastward rain chances will decrease as we head into Friday afternoon with dry conditions expected through much of the weekend. Temperatures will remain quite chilly on Friday with highs in the low 50s. Friday night, temperatures will fall into the 30s across much of the region and temperatures could drop to right around freezing across Kenedy, Brooks, Jim Hogg and northern Zapata counties. Will keep an eye on the potential for a Freeze Watch/Warning, but at this time temperatures remain just shy of criteria (32 or below for 2+ hrs). A warm up starts on Saturday with highs in the upper 50s to around 60 degrees as southeasterly flow returns. The warm up continues through the weekend but afternoon highs will still remain shy of seasonal norms. Clearer skies overnight will allow for radiational cooling and low temperatures at least 5 to 10 degrees below normal. Another upper level trough moving across the Plains will bring another cold front through Deep South Texas late Sunday with cooler air moving back in for next week. While temperatures will not be quite as cold as the current cold snap, will still remain well below normal. As the aforementioned front passes, a coastal trough will set up in its wake bringing back rain chances through the remainder of the long term period. && .AVIATION... (00Z TAFS) Issued at 540 PM CST Wed Jan 8 2025 A widespread low cloud decks with ceilings between 3500 to 6000 ft, except MVFR ceilings at BRO, and moderate to gusty prevail across Deep South Texas early this evening. Ceilings will continue to lower through the evening with MVFR and then IFR late tonight. Periods of light rain and/or drizzle and mist will start to develop later this evening and continue through much of the period. The best potential for rain and/or drizzle will be across the Lower Valley, BRO and HRL. Reduced visibility of around 4SM will be possible tonight and Thursday as pockets of light to moderate rain/drizzle develops. Moderate to gusty north winds early this evening will decrease through the evening and overnight hours. Light to moderate north winds are expected to continue on Thursday. && .MARINE... Issued at 151 PM CST Wed Jan 8 2025 Now through Thursday night...A tightening pressure gradient in response to a deepening coastal low/trough will result in increasing winds and rough seas over the Gulf waters and the Laguna Madre through the period. As a result, a Small Craft Advisory is in effect through Thursday evening for the Gulf waters and the Laguna Madre. Periods of light rain and/or drizzle may result in reduced visibility as well. Friday through Tuesday...Adverse marine conditions will continue off the lower Texas coast into Saturday morning. As a low pressure system moves into the SE US winds and seas will decrease Saturday with more favorable conditions returning by Saturday afternoon. Another cold front will push through the waters off the lower Texas coast late Sunday with winds and seas increasing in its wake which will lead to Small Craft Advisory conditions beginning Sunday night and lingering into the workweek. Rain chances will continue through the period, briefly drying out on Saturday. && .PRELIMINARY POINT TEMPS/POPS... BROWNSVILLE 40 51 43 52 / 90 70 90 50 HARLINGEN 39 48 39 52 / 70 70 90 40 MCALLEN 38 47 42 55 / 60 50 80 30 RIO GRANDE CITY 37 44 41 54 / 40 50 80 30 SOUTH PADRE ISLAND 48 57 48 55 / 90 80 90 60 BAYVIEW/PORT ISABEL 42 52 42 54 / 80 80 90 50 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...High Rip Current Risk through Thursday afternoon for TXZ451-454- 455. GM...Small Craft Advisory until 6 PM CST Thursday for GMZ130-132-135- 150-155-170-175. && $$ SHORT TERM...22-Garcia LONG TERM....68-McGinnis AVIATION...63-KC
Area Forecast Discussion
National Weather Service Cheyenne WY
505 PM MST Wed Jan 8 2025 .KEY MESSAGES... - High wind and blowing snow concerns continue through the evening for the wind prone areas. - New snow accumulations tonight and winds increase again tomorrow, resulting in continued blowing snow potential. Light totals expected in the valleys and plains (mainly around 1"), greater amounts in the mountains (6"+). - Another system brings widespread snow chances late Friday through early Sunday as wintry temperatures stick around through early next week. - Milder conditions appearing more likely mid next week. && .SHORT TERM /THROUGH THURSDAY NIGHT/... Issued at 323 PM MST Wed Jan 8 2025 Quite the dynamic pattern has set up aloft with an anomalous ridge just off the Pacific Coast bounded by a deep closed low over the Baja. A trough over the Canadian Rockies is in the process of digging into the Northern Plains, which will transition nearly meridional flow over Wyoming to more west/northwesterly. Another upper trough is centered over the Great Lakes. At the surface, an expansive high pressure stretches from the Gulf Coast to the Pacific Northwest. This high is anomalous as well, recording 1040mb over the Rockies, and registering around the 99%ile of climo per NAEFS ensembles. The surface pressure gradient supported high winds in the prone areas again today. This evening and tonight... A potent shortwave preceding the main longwave trough cuts across the northern Rockies and High Plains, while a surface cold front lines up to traverse the region. Behind the front, the Northwest US lobe of surface high pressure expands over the Rockies and again pushes 1040mb. These factors, along with sufficient lift and moisture, will result in a new round of snow shower activity and blustery winds. Used a general blend of HREF and HRRR for coverage and timing of PoP, which is maximized 03-12z. Thermal profiles would suggest a fairly drier snow, especially as SLR`s surpass 12:1 over the Neb panhandle, 15:1 over the Wyo plains, and 18:1 in the mountains. With northwesterly low level flow, upslope is maximized over the Snowy and Sierra Madre ranges, east of Laramie along the divide, and northern Dawes Co along the Pine Ridge. Considering the progressiveness of the system and the lack of overly abundant low level moisture, precip amounts should remain light overall, with the exception of the mountains. A couple bands of 1-2" snow totals are possible near the eastern Wyo ridges over toward the Pine Ridge, while most of the plains and Neb panhandle should stay under 1". Kept the Winter Wx Advisory for I-80 zones from Cheyenne to Rawlins due to 6"+ totals in the higher terrain and the continued blowing snow component. As for min temps, values will be seasonable (10s, lower 20s) and hold well above this morning`s observed temps (widespread subzero). Increasing cloud cover and winds should insulate and mix the near normal -7C H7 temps. Tomorrow... Snow showers continue through about midday, especially the southeast half of the CWA. Northwest winds steadily increase from sunrise to midday as 6hr surface pressure rises exceed 7mb and an approaching PV anomaly pushes to 500mb. As opposed to a more localized high wind setup experienced today, tomorrow supports a broadbrushed blustery day across the region. Despite the widespread breezy conditions, in-house wind procedures and NBM90 guidance fall short of warning criteria. Peak gusts of 40-50 mph are anticipated, especially east of the divide. Depending on the duration of the snow shower activity, an extension or perhaps expansion of the Winter Wx Advisory may be needed as more of the falling snow correlates to greater wind speeds. Strong cold air advection in the wake of the front and in the vicinity of the upper trough axis will keep max temps chilly across the area. In fact, some guidance suggests a steady or non-diurnal temp trend, so not expecting much recovery after the snow showers dissipate. Trended forecast highs down toward the cooler numerical guidance, which still registers near the 75%ile of the NBM envelope. Temps range from single digits in the mountains, upper 10s to 20s in southeast Wyo to near freezing in the Neb panhandle river valleys. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Issued at 323 PM MST Wed Jan 8 2025 Northern Flow stays with us from Friday through the weekend to keep overnight temperatures in the teens to single digits. Friday night Saturday, a trough moves through our region as an Alberta CLipper pushes through the Northern Plains. This trough will push against the Pacific ridge sitting over the west coast creating some pretty gusty winds. Looking at the Craig to Casper height differences at 850 level those values range between 60 to 94 meters with the 94 meters peak occurring at 03z Saturday. The height differences drop below 60 by Saturday afternoon. The local high wind machine learning algorithm also keeps the probability for high wind gusts near or slightly above 80 percent from Friday afternoon to Saturday afternoon to increase confidence in warning criteria wind gusts. Along with the faster winds, this trough is also expected to produce some precipitation as well but, mainly for the mountain ranges. For the the counties east of I-25, the probability for greater that 0.25 inches of snow ranges from 10 to 20 percent on Saturday. Another shortwave moves through the area Sunday into Monday to give us elevated wind gusts but not warning level criteria. Craig to Casper heights remain in the 30`s and 40`s Sunday into Monday but higher values are needed to see wind gusts to reach warning levels. Given the continual North to northwest flow, the biggest uncertainty is how much moisture is in the atmosphere come Sunday to support light snowfall. Tuesday and Wednesday, The Pacific ridge start to move close to the Rocky mountains to raise temperatures back into the 30`s and 40`s. The region also looks to remain relatively dry these two days as the ridge continues to push east. Despite temperatures being in the 30`s and 40`s during the day, temperatures look to remain in the teens and single digits at night. Likely due to possible clear skies under the ridge allowing for efficient radiational cooling. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 505 PM MST Wed Jan 8 2025 A fast moving upper level trough pushing south out of Canada will move across the region tonight. This system will bring breezy conditions and a quick shot of snow to the southeast Wyoming and western Nebraska terminals between 03z and 16z tonight into early Thursday morning. HAZARDS/WEATHER TRENDS: Primary uncertainty tonight and early Thursday is timing of the precipitation and IFR conditions. It is awfully dry near the surface currently with dewpoints in the teens and single digits at most places. Snowfall will likely be delayed and not make it to the surface at first. Expect KRWL and KCDR to see the snow and IFR conditions likely between 03z and 08z. Further south towards KAIA and KSNY, activity will likely hold off until after 09z. Conditions are forecast to improve rapidly between 15z to 18z Thursday. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...High Wind Warning until 8 PM MST this evening for WYZ106-110. Winter Weather Advisory until 6 AM MST Thursday for WYZ109-110- 115>117. NE...None. && $$ SHORT TERM...DS LONG TERM...MM AVIATION...TJT
Area Forecast Discussion...UPDATED
National Weather Service Peachtree City GA
631 PM EST Wed Jan 8 2025 ...New 00Z Aviation Discussion... .SHORT TERM... (This evening through Thursday) Issued at 345 PM EST Wed Jan 8 2025 Like yesterday the current satellite loop shows decreasing clouds across NW GA with mostly clear skies across the rest of the state. Surface high pressure is still slowly building into the area from the Northern Plains through Thu afternoon with near zonal 500mb flow. There is a weak dry cold frontal boundary that sweeps through the state from NW to SE Tonight which will help to reinforce the cold airmass over the area. Looking for temps Tonight to bottom out in the teens along and north of the Interstate 85 corridor with lower 20s elsewhere. High Temps Thu rebound mainly into the 40s with some upper 30s across the N GA mountains. Thu will be our last dry day this week as the next frontal system beginning to develop in the western gulf Today will move NE and into our area Thu night into Friday morning. Extreme western portions of the state will see some light snow showers just before sunrise Fri morning but we will see our winter weather mainly move in during the day Friday. 01 && .LONG TERM... (Friday morning through next Tuesday) Issued at 345 PM EST Wed Jan 8 2025 Key Messages: - Primary impact continues to be winter weather on Friday into Friday night. Greatest probability of impactful wx will be in northern Georgia through metro Atlanta. Areas south of I-20 continue to remain a bit more uncertain. - Snow looks to be primary precip time in northern Georgia and the mountains as of this forecast package. Amounts look to be in the 3-6" range. Can`t rule out some mixing in of sleet or freezing rain that could limit accumulations a bit in some locations. - Precip type continues to look primarily frozen in the metro and points east. Snow would be the onset precip type that could accumulate and impact morning commute. A switch to sleet and/or freezing rain would during the afternoon. Can`t rule out a brief transition to rain. - South of I-20, uncertain if we can remain below freezing during the day on Friday. We will likely start during the morning hours with snow, but this would quickly transition to rain. Forecast: Not too much change in the overall forecast with the update to this forecast package. Starting to get access to some of the higher resolution guidance, and it is painting a similar picture to what the forecast has been thus far. Snow expected in the north, a transition area in the metro and points east, including Athens, and then for central Georgia an initial period of snow before a quick transition to a cold rain. Synoptic setup is as follows - cold air mass continues to linger in the area during the day on Thursday. We will see another wave pass by the area on Thursday aloft that will be dry, but will push a reinforcing shot of cold air in on Thursday into Thursday night. This will set the stage for winter precipitation on Friday, allowing our surface air mass to be cold enough for some sort of frozen precip. Two significant upper level features, a cut off low over the desert southwest, and another shortwave quickly moving within the polar jet, will phase together and eject into the southeast on Friday into Saturday. Wave will interact with significant baroclinicity in place across the Gulf coast with cold air settled in place and generate strong surface low within region of PVA ahead of it. This will bring precip and the potential for winter weather across wide swath of the south, including our CWA. Confidence remains high in seeing impactful snow accumulations across northern Georgia. Ensemble guidance has come down a little bit in totals in these areas, and this forecast package reflects that a bit. A few things going on here - the biggest being models seeming to be a bit warmer at the surface, as well as some models seeming to better resolve a warm nose. Precip would likely start during the morning hours, around or a bit after sunrise, and remain snow for a good bit of the day, if not the entire day. Current forecast amounts would be between 3-6" inches in this area. A huge caution with looking at 10:1 ratio forecast maps - current SLRs used in this package are closer to 5 and 6 to 1. Sounding profiles are near isothermal for a good chunk of low levels and approaching mid levels. This is likely to be a wet, heavy snow. There is a chance that would could see some sleet or freezing rain mix in, especially if some of the more aggressive guidance with the warm nose occurs, which would act to limit accumulations to the lower end of projections. In metro Atlanta and points eastward, including Athens, we are expecting to see several different phases of precipitation. The initial onset during the morning hours looks like it should be snow. Hi res models show significant drying in the low levels just off the surface that will likely quickly adjust thermal profiles to be below freezing in the entire column as initial snowfall sublimates while falling. From there, a transition to sleet and possibly freezing rain is expected to happen moving into the afternoon. Big model discrepancy as to how quickly this transition will happen. Latest HRRR (18Z), for instance, has come in with an impressive solution that would likely pile up an inch or two of snow in these areas before transitioning in the late afternoon as the warm nose pushes into the area. Other models have even earlier transition (for instance, 12Z 3km NAM) as warm nose in these push in even faster. Right now, forecast expectations are 1-3 inches of snow and/or sleet with the potential for a tenth to 2 tenths of ice. Really want to emphasize an important point here - if models which show earlier transition are right, there is absolutely potential for a decent ice storm, with decrease in snow totals and increase in ice totals. Please stay tuned to this portion of the forecast. Other bit of uncertainty is on surface temperatures in the metro and areas east (and really south into central GA). We will need to find a way to offset the latent heat release required to freeze liquid water to objects for any significant ice storm. Signs of in-situ wedge being able to form is noted in a lot of the model guidance. This could certainly be a way for us to "hang on" to even colder surface temps than many of the models have shown. Dynamic cooling may also be possible, especially if models showing substantial 925 mb-850mb drying in lead up to storm are accurate. This would allow us to physically drag some of the colder air aloft down to the surface, especially in heavier precip. Finally, getting into central Georgia - initial onset looks like it may also be snow during morning hours as the initial WAA pushes through the area as the surface low starts to progress east. The expectation is that it will be a bit more difficult to hold on to the cold air here at the surface. A period of sleet or freezing rain may be possible in some locations before a quick transition to a cold rain. This would likely lead to limited impacts during the morning hours. A winter weather advisory may be needed in some counties that are south of the current winter weather watch to cover morning impacts, but given high uncertainty in potential impacts, will hold off on any watch issuance for these areas. Speaking of the winter weather watch - small southward expansion for a few counties in eastern Georgia with this update, otherwise no large changes. The overnight forecast package will be the earliest we see any upgrades to these, and given onset time, and potential uncertainties, it is possible this may not occur until the afternoon tomorrow. Want to emphasize the timing of when impacts may begin in the current watch area - snow may begin falling right across the morning commute for many areas, especially to the west. Surface temps at onset are in the mid to upper 20s and it will have been quite cold in the lead up to this storm. Soil temps are cool per UGA mesonet near surface. Put it all together, and snow will likely begin to stick pretty quickly, especially if we get any decent snowfall rates. This would likely include roadways. Untreated roads may become icy and hazardous very quickly. If you can, please consider staying off the roadways on Friday. Winter weather looks to come to an end on Friday night into early Saturday morning. Cold air settles back into the area, and combined with any potential snowpack, highs on Saturday are only in the 30s to 40s for most of the area. Saturday night is looking cold. Widespread teens are expected including into areas even south of I- 20. Areas in central Georgia will drop into the lower 20s. For the rest of the long term, temperatures are pretty average for this time of year with not much to talk about (just yet). Lusk && .AVIATION... (00Z TAFS) Issued at 628 PM EST Wed Jan 8 2025 VFR conditions through the forecast with just a few high clouds. Winds will remain NW 8-12kts with some lingering gusts up to 22kts at KATL through the evening before decreasing to 6-10kts later tonight and 5-8kts Thursday. //ATL Confidence...00Z Update... High confidence on all elements. SNELSON && .PRELIMINARY POINT TEMPS/POPS... Athens 20 45 25 34 / 0 0 0 100 Atlanta 21 42 27 34 / 0 0 10 100 Blairsville 12 39 20 32 / 0 0 0 100 Cartersville 17 42 23 34 / 0 0 10 100 Columbus 22 49 29 42 / 0 0 20 90 Gainesville 20 45 27 33 / 0 0 0 100 Macon 22 47 26 40 / 0 0 10 90 Rome 18 42 24 35 / 0 0 10 100 Peachtree City 20 45 25 36 / 0 0 20 100 Vidalia 24 47 28 48 / 0 0 0 60 && .FFC WATCHES/WARNINGS/ADVISORIES... Winter Storm Watch from Friday morning through Saturday morning for GAZ001>009-011>016-019>025-027-030>039-041>060. Cold Weather Advisory from 11 PM this evening to 9 AM EST Thursday for GAZ041-042-052>054-056-066>073-078>086-089>098- 102>113. && $$ SHORT TERM...SNELSON LONG TERM....Lusk AVIATION...SNELSON
Area Forecast Discussion
National Weather Service Fort Worth TX
828 PM CST Wed Jan 8 2025 ...New Short Term, Aviation... .KEY MESSAGES... - Winter Storm Warning has been expanded to include Montague County. No other changes were made to the Winter Storm Warning and Winter Weather Advisory. - Have increased snow amounts along and north of I-20 based on latest guidance, but storm total snowfall remains in the 1 to 5 inch range. There is increasing concern of higher totals where heavier bands set up, and some areas of North Texas could receive considerably more snow (possibly up to 8 inches). These heavier snow totals are most likely in our Red River Counties but could potentially occur in northern parts of the Metroplex. - Lowered ice amounts slightly based on latest guidance, but still anticipate up to one tenth of an inch of ice for most of the forecast area except our far southern counties. - Main travel impacts are expected to begin Thursday morning and peak from Thursday afternoon through Friday morning, before improving some Friday afternoon. && .SHORT TERM... /NEW/ /Tonight through Thursday Night/ Quiet and cold evening across North and Central Texas with current temperatures in the 30s but dewpoints very low in the 10s/20s. The dry airmass in place will be key to the smorgasbord of precip types we are anticipating tomorrow with the winter storm. Latest guidance such as the HRRR indicate precip will rapidly spread into the forecast area around 10Z and spread over all of North and Central Texas by 15Z. Forecast soundings show a warm nose aloft initially along with very dry air in the low levels, so a mix of freezing rain and sleet is most likely when precip starts. However, as the airmass saturates and temperatures fall to the wet bulb temp, precip should transition by late morning to a cold rain in our southern counties, a mix of sleet and snow in our central counties, and all snow in our northern counties. As slightly warmer air advects northward during Thursday afternoon, the rain/mix/snow line should also shift northward with the HRRR/NAM suggesting it could move as far as just north of the Metroplex. By Thursday evening, however, CAA will cause the transition zone to shift back to the south with rain changing back to sleet/snow Thursday night before ending by Friday morning. Needless to say, the transition zone with the mix of precip types is the most challenging part of the forecast - with our northern counties expected to see mostly snow and our southern counties a cold rain. The exact location of the rain/mix/snow line has huge implications on which areas will see more ice versus snow. Latest models continue to show the transition zone shifting around roughly near the I-20 corridor through the event, giving the Metroplex a mix of all precip types. However, if the transition zone does not move as far northward as guidance indicates, the Metroplex could see considerably more snow (which some guidance such as the GFS suggest) - and vice versa, if the transition zone shifts further north, less snow and more rain or ice for the DFW area. Based on the latest guidance, have upped snow amounts slightly across our northern half and decreased ice amounts a tad, but amounts remain in the same range as our previous forecast. It will be quite fascinating meteorologically to see how this event eventually pans out. Shamburger && .LONG TERM... /Issued 246 PM CST Wed Jan 8 2025/ /Friday Morning Onward/ By Friday morning, the majority of the rain and winter precipitation will be east of the region, with only a scattered chance of snow in northeast Texas and rain in far southeast Central Texas. Travel impacts will persist through at least the morning commute as sub- freezing temperatures and slick spots on roads and bridges will linger through mid-morning. The base of the upper level trough will pass overtop the region during the day on Friday, completely ending precipitation chances by the afternoon. Unfortunately, cloud cover will be slow to clear out, with mostly cloudy skies lingering through much of the afternoon. This will inhibit better warming of air temperatures, and in turn, better melting. With the cloud cover and snow, temperatures on Friday will be slow to warm above freezing, with some across North Texas not reaching 32 until closer to noon. Temperatures will eventually peak in the mid-upper 30s and will allow for some melting during the afternoon. However, overnight temperatures will once again bottom out in the upper teens and low 20s along the Red River and north of I-20, where snow amounts are expected to be greatest, and low-mid 20s elsewhere. This will promote the refreezing of any water left on roadways. If you venture out on Saturday morning, take caution when driving as there will be slick spots on roads, particularly untreated roads and elevated bridges and overpasses. Well to our northwest, an open shortwave trough will swing across the Central Plains over this upcoming weekend, sending a cold front south. The front will move through the region over the day Sunday, shifting winds to the north. The better lift associated with the upper level trough and its attendant surface low will remain well displaced to our north, as well as any appreciable moisture. Therefore, the frontal passage will remain dry with only a bit of cloud cover forecast. One interesting point to note is the continued surface cyclogenesis across the Texas Panhandle further south along the front. This feature will enhance surface winds and cold air advection across the region as the front moves through. Post-frontal surface high pressure will quickly slide into the region overnight, keeping winds light. As a response to all of the above, Monday low temperatures will bottom out from the mid 20s to around 30. Over the first half of next week, expect a gradual warming trend, with overnight lows returning into the upper 20s to mid 30s and afternoon highs into the upper 40s to mid 50s by the end of the forecast period. Prater && .AVIATION... /NEW/ /00Z TAFs/ VFR conditions are expected to continue through 11-12Z when MVFR conditions develop due to a wintry mix of precipitation rapidly spreading across airports. Main precip types will be SNPL initially and metroplex airports with FZRA at ACT, with RA mixing in by Thursday afternoon, before transitioning back to SNPL by Thursday evening. Cigs/vis will continue to deteriorate to IFR by late Thursday morning with IFR/LIFR conditions through the rest of the TAF period. and continuing through the remainder of the TAF period. Light north winds this evening will become southerly overnight, then back to easterly and northerly during the day on Thursday into Thursday evening. Shamburger && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 29 34 30 36 24 / 10 100 90 5 0 Waco 30 37 32 38 24 / 40 100 100 5 0 Paris 26 33 30 34 18 / 5 90 100 30 0 Denton 26 33 27 35 20 / 10 100 90 5 0 McKinney 26 34 29 35 20 / 10 100 100 20 0 Dallas 29 35 30 37 23 / 10 100 100 10 0 Terrell 27 36 30 36 22 / 5 100 100 20 0 Corsicana 30 37 32 38 27 / 10 100 100 10 0 Temple 29 37 31 38 24 / 40 100 100 5 0 Mineral Wells 27 33 28 35 21 / 40 100 80 0 0 && .FWD WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning from 6 AM Thursday to noon CST Friday for TXZ091>095-102>107-117>123. Winter Weather Advisory from 6 AM Thursday to noon CST Friday for TXZ100-101-115-116-129>135-141>148-156-157-159-161. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
553 PM CST Wed Jan 8 2025 .KEY MESSAGES... - Light snow will move from west to east across the area Thursday. Most areas will see less than an inch of snow, however slick spots are possible. - Clipper system to bring another chance for snow over the weekend. Confidence in increasing in the potential for a few inches of accumulating snow, though timing is still uncertain. && .DISCUSSION... Issued at 219 PM CST Wed Jan 8 2025 Sunshine and temperatures in the teens are the theme across most of south central Minnesota and western Wisconsin this afternoon. The only difference in sky cover is captured on satellite across central Minnesota, where an area of stratus is slowly meandering east from roughly AXN towards STC (and locations to the north). The forecast will remain dry tonight, with the upper ridge axis positioned above the Upper Midwest. Water vapor imagery shows ascent across southern Saskatchewan and northern Montana, associated with an eastward moving wave that will bring the chance for light snow on Thursday. High clouds will build ahead of this feature, which will combine with light southerly flow to prevent most areas from falling below the double digits tonight. The aforementioned wave is progged to slide east across the Dakotas tonight and will send a surface cold front from west to east across Minnesota/Wisconsin tomorrow. We are expecting a "high PoP/low QPF" precipitation scenario, where may locations see snowflakes fly, however poor moisture (a few hundredths) and standard SLR`s (~12:1) cap snowfall below an inch for most communities. The highest amounts (Say an inch and a half in isolated settings) appear to be along and north of I-94 in Minnesota, which will be tied to better forcing aloft. Nonetheless, forecast soundings do capture a few hours of deeper saturation in tandem with sufficient omega forcing to produce light snow across much of the area. Given high confidence light snow and minor accumulations, we collaborated with neighboring offices to boost PoPs into the ~60-80% range across west central Minnesota, where hourly precipitation >0.01" probabilities are the highest per the 12z HREF. While this will not be a major snowfall, the introduction of even a half to quarter inch of snow may be enough to produce slick spots Thursday afternoon & evening. A few snowflakes may linger amid the northwest flow on Friday morning, before the southward movement of 1020s Canadian high pressure results in a brief period of quiet weather Friday afternoon-Saturday morning. A potent clipper, originating across northern Alberta, is progged to dive southeast across the Dakotas Saturday morning. Guidance depicts the ~1002-1004mb low moving southeast out of the Dakotas into Minnesota/Wisconsin Saturday evening through Sunday morning. The compact clipper is set to pivot over southern MN/northern IA, before lifting to the northeast towards eastern Wisconsin (towards the region of warm advection). The track of the clipper will follow the thermal gradient, such that there will likely be additional support for precipitation from frontogenic forcing. Latest guidance has trended upward with QPF, with ensemble means suggesting a wide swath of ~0.1" liquid precipitation. A variety of individual ensemble members and deterministic counterparts have trended wetter, with perhaps upwards of ~0.2" of QPF. That`s plenty of moisture to work with for this time of year, especially given the expected higher ratio nature of these clipper events (SLR`s between 15-18:1 per the latest NBM and conceptually could be higher). For this reason, confidence is increasing in widespread accumulating snow over the weekend. We`ll have to fine tune the details over the coming days, as timing and duration of snowfall remain in flux, but the large scale pieces are pointing in a more likely direction for a few inches of snow. For this reason, we collaborated with neighboring offices to boost QPF through 18z Sunday, to reflect values closer to the ensemble mean referenced above. Additionally, we boosted PoPs Saturday night/Sunday morning, so the grids now feature 40-50% PoPs at all forecast points. The forecast dries out early next week, following the departing low. Cold advection across the Upper Midwest will work to drop temperatures into the single digits for highs Monday/Tuesday, along with the potential for sub-zero lows. Factor in what may end up being a fresh layer of snow and these values could end up even colder as we approach the end of the forecast period. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 545 PM CST Wed Jan 8 2025 Not much going on through Thursday morning. There is a narrow batch of MVFR stratus over central MN that will skim just north of MSP and may briefly impact RNH. After that, we`re waiting on an expected North to South oriented band to move across the area in the afternoon with a cold front. Timed that snow in with a blend of the NAMnest and HRRR for now. Snow won`t last more than 3 hours, with a brief 60-90 minute window of IFR snow possible at each airport. Winds will be southerly ahead of the snow, but a wind shift will be associated with the snow over to the WNW. KMSP...a little band of snow is expected to hit the airport between 19z and 21z. A brief period of IFR vis will be possible with snow, but this looks to be more of a nuisance type snow, with accumulations under 0.5" /OUTLOOK FOR KMSP/ FRI...MVFR early, then VFR. Wind NW 5-10kts. SAT...VFR. IFR/SN likely overnight. Wind S 5-10kts. SUN...MVFR/IFR/SN likely in mrng. Wind NW 10-15G25kts. && .MPX WATCHES/WARNINGS/ADVISORIES... MN...None. WI...None. && $$ DISCUSSION...Strus AVIATION...MPG
Area Forecast Discussion
National Weather Service Portland OR
339 PM PST Wed Jan 8 2025 .SYNOPSIS...High pressure will largely result in dry weather across the region. The main exception to this will be on Friday when a front will bring widespread light valley rain and mountain snow to the region with a few showers lingering over the higher terrain into the weekend. Another dry spell is expected early next week, albeit with cooler temperatures, mainly overnight. && .DISCUSSION...Now through Tuesday night...Models and their ensembles remain in good agreement regarding the synoptic scale pattern over the next week, suggesting varying degrees of upper level ridging over the Pacific Northwest aside from Thursday night/Friday when a transient 500 mb trough and attendant frontal system sweeps inland from the Pacific. Minimal impacts are expected with this system, however it will bring widespread valley rain and Cascade snow. Given the fast-moving nature of this frontal system, not expecting significant rain amounts in the lowlands or significant snow amounts in the Cascades. The NBM mean suggests 24-hr rain amounts around 0.25-0.30 inches across the interior lowlands with 0.25-0.4 inches along the coast and 0.5-0.75 inches along the west slopes of the coastal mountains and across the Cascade foothills. Not much snow is expected in the Cascades, generally only an inch or two. Prior to Friday`s system, expect more dry weather with near normal to slightly above normal temperatures. In addition, patchy valley fog is possible in the morning for outlying rural areas Thursday morning. Light post-frontal showers will continue into the weekend, however these showers will be mainly orographically driven and confined to the mountains. Upper level ridging returns early next week with another period of dry weather, even in the mountains. Easterly winds will also redevelop during that time in the Columbia River Gorge and eastern Portland/Vancouver metro, albeit nothing of significance for this time of year. Wind speeds at this time are not expected to reach impactful levels. What may be slightly more impactful are colder temperatures Monday night and Tuesday night; this is when low temps are forecast to dip into the low to mid 30s. Cannot completely rule out lows below 30 degrees in outlying rural areas where the NBM is showing a 50-75% chance. -TK && .AVIATION...VFR conditions prevail across the region this afternoon with just some scattered high cloud cover drifting overhead. Expect these VFR CIGs/VIS to persist through the evening hours. The main concern overnight will be the return of fog to the interior valleys 07-12z, especially the southern Willamette Valley due to the ridge of high pressure building overhead leading to mostly clear skies and light winds. The latest high resolution guidance like the HRRR and HREF does show a greater areal coverage of fog come sunrise Thursday than the last few nights. At least an increase in easterly winds will help to keep KPDX and KTTD VFR through the period. PDX AND APPROACHES...VFR conditions are expected through the period. East winds redevelop this evening however high resolution guidance depicts more variability in winds right at the terminal come 10-14z Thursday morning. -Schuldt && .MARINE...Current bouy data this afternoon shows seas have slowly calmed back below 10 feet with wave heights expected to further decrease to 5-7 feet at 12-13 seconds overnight. This is due to the return of relatively benign conditions expected to persist through Thursday as the ridge of high pressure rebuilds overhead and winds turn more offshore. It`s worth noting we could see some localized stronger easterly gusts of 15-20 kt out of gaps in the coastal terrain. Conditions deteriorate Thursday night into Friday as another front moves across the coastal waters accompanied by a decently large swell. After a brief period of southerly winds Thursday night, winds will strengthen out of the northwest and become gusty on Friday in the wake of the front. The Likelihood of Small Craft wind gusts sit around (70-90%) but the chance for Gales is rather low, less than 5%. The building westerly swell will also help to push seas back into the low to mid teens through early Saturday. Look for winds and seas to trend back down as high pressure builds back over the region Sunday through early next week. -Schuldt/CB && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 1 PM PST this afternoon for PZZ210. Small Craft Advisory until 10 AM PST this morning for PZZ251>253-271>273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland x.com/NWSPortland
Area Forecast Discussion
National Weather Service Springfield MO
550 PM CST Wed Jan 8 2025 .KEY MESSAGES... - Cold conditions will occur across the area into tonight. - Snow is likely across the area Thursday evening into Friday. - Generally dry conditions and closer to normal temperatures for this time of year in the Saturday through Tuesday time period. && .SHORT TERM /THROUGH FRIDAY/... Issued at 130 PM CST Wed Jan 8 2025 Synoptic overview and current conditions: Water vapor imagery and upper level analysis continue to show northwest flow over the forecast area with a strong cut-off low over the Baja region. Visible imagery shows a large area of stratocumulus across the forecast area which is leading to some scattered flurries. A large area of cold high pressure was centered over the plains with temperatures here over the Missouri Ozarks and extreme southeast Kansas still in the teens to mid 20s. Rest of the afternoon: The stratocu deck will persist in the afternoon with scattered flurries continuing with no accumulation expected. Temperatures will likely not get out of the 20s this afternoon, with the best potential over south central MO near the AR border. Tonight: Another cold night is in store as the area of high pressure drifts overhead. The stratocu should clear out and with a light wind we should dip back into the single digits to teens. Thursday: The upper level closed low should begin to open up and start to eject eastward. A surface low should start to develop along the Gulf coast of Texas. Upper energy and jet dynamics should start to move into the area by late in the day with some light snow developing during the late afternoon in the southwest portion of the CWA. Thursday night-Friday snow potential: The surface low will continue to track along the Gulf coast with the upper wave tracking east into the plains. Upper energy will continue to push across the area. RAP showing the potential for some frontogenetic forcing at 700 and 850 mb across the area with the potential for some southwest to northeast snow bands. With the surface low so far to the south, the main snow accumulations over our area will likely be within these narrow snow bands and there may be several that set up. Unfortunately, while we can predict a generalized area where these mesoscale bands may set up, it is difficult to pinpoint exactly where they might occur. Outside of these narrow bands, snowfall amounts will be less than the overall forecast, and within these bands, it may be slightly higher totals. We will likely be going with a winter weather advisory from around 5 pm Thursday through 6 pm Friday to account for the accumulating snow. Generalized snow amounts over the area will be in the 2 to 4 inch range, however may be lower outside of the main snow bands and slightly higher within the bands. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 130 PM CST Wed Jan 8 2025 After this system exits the area, we should continue to see lower than normal temperatures persist, however they will not be as bitterly cold as we`ve had the past few days. Lows in the teens to 20s and highs in the 30s are expected. An upper level wave Saturday night into Sunday will bring cloud cover to the area, but the majority of any precipitation should remain north of the area. After this wave passes through, temperatures will begin to moderate to more normal towards the middle to end of next week with little to no precipitation. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 549 PM CST Wed Jan 8 2025 VFR conditions and light winds will continue through most of this TAF period. However, snow will move through the region late Thursday into early Friday, with light to moderate snowfall and IFR to LIFR conditions expected. && .SGF WATCHES/WARNINGS/ADVISORIES... KS...Winter Weather Advisory from 5 PM Thursday to 6 PM CST Friday for KSZ073-097-101. MO...Winter Weather Advisory from 5 PM Thursday to 6 PM CST Friday for MOZ055>058-066>071-077>083-088>098-101>106. && $$ SHORT TERM...Lindenberg LONG TERM...Lindenberg AVIATION...Titus