Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/30/24


Area Forecast Discussion
National Weather Service La Crosse WI
549 PM CST Fri Nov 29 2024 .KEY MESSAGES... - Cold & dry for much of this weekend with flurries exiting the area today. Wind chills during the morning hours this weekend will be between 0 and 10 degrees below zero and only recovering into the single digits during the afternoon. - Conditions remain cool and dry until Tuesday night with precipitation chances (20-50%) returning to the area and a brief return to seasonable conditions with highs in the 30s for Wednesday. && .DISCUSSION... Issued at 132 PM CST Fri Nov 29 2024 Rest of Today - Tuesday: Cold, Dry with Lingering Flurries Broad troughing over the eastern CONUS today continues to remain the key feature synoptically as a fairly robust continental polar airmass remains in place across the region for today and through the weekend. As we continue through much of the day, an axis of dry air noted on GOES-16 water vapor imagery and highlighted in guidance with continued to pivot through portions of the region. As this occurs, 29.15z RAP soundings would suggest fairly uniform drying of the troposphere throughout the rest of the afternoon aside from some transient saturation in the low- levels. Ongoing flurries will not have a difficult time maintaining due to this low-level saturation being in the dendritic growth zone coupled with some weak near- surface omega. However, surface observations continue to suggest the aforementioned dry slot has continued to aid in scouring our the low-level stratus resulting in lesser coverage of flurries across eastern portions of the local area. Certainly an impressively dry airmass though with recent NAEFS percentiles having precipitable waters of 0.1" being around the lowest percentile of reanalysis climatology across portions of our region. As we head into the weekend and early next week, continued cold air reinforcement with the upper-level trough and northwesterly flow will keep our air temperatures cold for this time of year with highs generally in the anywhere from the upper teens to upper 20s through Tuesday. Confidence continues to remain high that wind chills will fall to around minus 5 to 10 degrees during the morning hours areawide this weekend with the 29.12z HREF having medium probabilities (30-60%) for wind chills below minus 10 degrees on Saturday morning. Additionally, with somewhat breezy conditions, still expecting wind chills to remain in the single digits into the afternoon hours this weekend, so overall will feel quite chilly throughout the day. Otherwise, hints of low- level saturation in recent RAP/HRRR soundings in the dendritic growth zone over the weekend would suggest a few stray flurries cannot be ruled out. However, given exactly how little moisture is present from the aforementioned dry airmass advecting into our region, this would be very low confidence and would not pose any impacts regardless. Tuesday Night - Thursday: Seasonable with Precipitation Chances As we head towards Wednesday, the overall troughing pattern flattens slightly in deterministic guidance with some subtle ridging being able to sneak in ahead of a shortwave and surface low passage to our north on Wednesday. This will allow for some warm advection to squeeze in for Wednesday with the 29.00z grand ensemble (GEFS/EC/Canadian ensemble) having median high temperatures across the region generally in the 30s with relatively low inter-quartile spread of around 5 degrees. This generally appears to be short-lived with cold air advection working in behind this shortwave. Still some uncertainty on the timing on when this cold advection reaches our area with vast inter-quartile spread (roughly 15-20 degrees of spread) in the 29.00z grand ensemble median high temperatures for Thursday at La Crosse with highs anywhere from lower 20s to middle 30s. Precipitation chances likely would manifest as snow during this period with the 29.13z NBM showing every solution that has precipitation for Tuesday night with the snow precipitation type (anywhere from 20-50% of members east of the Mississippi River) which would be consistent with the northern trajectory of the shortwave and cold air advection regime behind it. Still questions remain on the track and intensity of the wave as it skirts north of the region though. Overall confidence is currently highest across north-central WI for measurable snow on Tuesday night/Wednesday (60- 80% chance in the 29.00z grand ensemble) with lessening confidence further southwest. Regardless, the overall pattern over the next week can be summarized to generally cooler than normal temperatures with the northerly flow regime and light snow chances with any pieces of shortwave energy that can approach the region. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 549 PM CST Fri Nov 29 2024 Currently watching a MVFR deck of clouds moving through the western suburbs of the Twin Cities. Many of the models are not handling these cloud. The GFS has some MVFR clouds, but they dissipate as they move southeast into the area. The HRRR also shows them and it brings them southeast through KRST between 30.03z and 30.07z and KLSE between 30.05z and 30.09z. For now, went with scattered MVFR deck between 30.03z and 30.06z and kept KLSE clear. Might even have to add some snow flurries. We will continue to monitor them through this evening. Otherwise, there looks to be no concern with low ceilings for the remainder of the TAF period. As diurnal mixing occurs on Saturday, west northwest winds around 290 degrees will be sustained around 15 knots with gusts of 20 to 25 knots. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ DISCUSSION...Naylor AVIATION...Boyne
Area Forecast Discussion
National Weather Service Charleston SC
908 PM EST Fri Nov 29 2024 .SYNOPSIS... High pressure will build across the area through the middle of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... The boundary layer has decoupled across many areas this evening with temperatures falling quickly with calm winds and clear skies. The gradient is expected to tighten slightly over the next few hours as a weak shortwave passes through, which may cause a brief recoupling in some areas. However, guidance is similar in showing winds going calm/light again after 2-3 AM as the gradient relaxes once again and the boundary layer decouples. The situation looks favorable for widespread frost/freeze away from the immediate coast with lows poised to drop into the upper 20s well inland to the lower 40 sat the beaches. The earlier modifications to the going Freeze Warning and Frost Advisory look on track with light drainage winds helping to push lower- mid 30s well into much of the Georgia coast. Only coastal portions of McIntosh and Bryan Counties look to escape significant frost/freeze conditions along with far eastern areas of Chatham County including Tybee Island and possibly Wilmington Island. Farther up the lower South Carolina coast, areas around Hilton Head, the Broad River and many of the small islands in central/southern Beaufort County look safe along with the immediate coastal communities of Colleton and Charleston Counties, including Downtown Charleston. The growing season for Southeast South Carolina and much of Southeast Georgia will end tomorrow. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/... Broad troughing aloft will prevail across the East Coast into Monday, while high pressure will build into the local area from the west. A rain-free forecast has been maintained, with the high pressure ushering in a dry, cool airmass. Temperatures Saturday night are forecast to dip into the upper 20s far inland, with 30s along the coastline, the beaches should remain near 40. Areas to widespread frost is likely to develop away from the beaches, however the local Frost/Freeze season ends on Saturday, November 30th. Therefore, we will no longer issue Frost/Freeze Watches or Warnings for the season. && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... Little change in the overall synoptic pattern is expected through the work week. Northwesterly flow aloft will dominate as the east coast is under the influence of large scale troughing in the upper levels. At the surface high pressure will build into the region, centered over the southeastern states. The main forecast highlight will be the below normal temperatures. Highs on Tuesday will likely struggle to get out of the 40s across many locations, with overnight lows in the 20s to around freezing directly at the coastline. A slight warm up is expected Wednesday and into Thursday, with highs Thursday in the low to mid 60s. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... 30/00z TAF Discussion: KCHS/KJZI/KSAV: VFR. Extended Aviation Outlook: VFR. && .MARINE... Tonight: Winds will surge overnight with the passage of a shortwave aloft. North winds will increase to 20-25 kt for several hours overnight per the latest trends noted in both the RAP and H3R. The Small Craft Advisory has been expanded to include all remaining nearshore legs with the late evening update. Only the Charleston Harbor looks to remain out of advisory level winds. Seas will build 2-4 ft overnight. Saturday through Wednesday: High pressure will prevail across the marine waters through the week, with generally tranquil conditions forecast across the waters. Northwesterly winds are forecast, generally around 10 to 15 knots, with some gusts approaching 20 knots. Seas should average 2 to 4 ft through the week. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...Freeze Warning from 1 AM to 9 AM EST Saturday for GAZ087-088- 099>101-114>116-118-137-138. Frost Advisory from 1 AM to 9 AM EST Saturday for GAZ117-119- 140. SC...Freeze Warning from 1 AM to 9 AM EST Saturday for SCZ040- 042>045-047-050-052. Frost Advisory from 1 AM to 9 AM EST Saturday for SCZ048-049- 051. MARINE...Small Craft Advisory until 7 AM EST Saturday for AMZ350-352- 354-374. && $$
Area Forecast Discussion
National Weather Service Cleveland OH
1044 PM EST Fri Nov 29 2024 .SYNOPSIS... A low pressure system north of the region will keep a surface trough across the area into the start of next week. Another low pressure will move east across the northern Great Lakes, impacting the area again for mid-week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... Lake effect snow continues to pile up along the northeast lakeshore leading to very hazardous conditions. Snowfall reports this evening have surpassed a foot and a half in Ohio with reports of over 2-2.5 feet in Erie County Pennsylvania. We have received reports of stranded motorists and downed limbs due to the weight of the snow. Travel in eastern Lake, northern Ashtabula, and Erie County PA is strongly discouraged as this is becoming a very serious situation. Unfortunately heavy snow continues to fall with rates of 1 to 2 inches per hour. A heavy band has re-oriented across eastern Lake and Ashtabula county while another heavy band is across eastern Erie County PA into New York. Snow is expected to continue through the night with strong intensity given westerly flow through 700mb, ample moisture, a warm lake and a cold airmass. Not until the southwest flow lifts the band out over the lake on Saturday morning is a real break expected. The combination of the duration and high snowfall rates means 12-18 inches are likely under the heavier band and can not rule out a few places(most likely in Ashtabula County) exceeding another 2 feet. A sharp cut-off still remains to the south with southern portions of Geauga, Ashtabula, and Crawford Counties likely to receive little if any accumulation. In Cuyahoga County, Euclid is the main concern and have chosen to leave the Advisory in effect given the close proximity to the heavy band. Most of Cuyahoga County will receive little or no snow. Colder air located south of the lake will continue to favor the surface trough holding on along the lakeshore overnight. The RGEM has been a preferred model which continues to focus the trough axis near the shoreline, allowing less inland extent of snow. Unfortunately this does place the heaviest of the snow in areas that have already been hit hard. Roads are becoming impassible in this dangerous situation. A concerning trend on the 00Z/30 HRRR shows the band struggling to clear Erie County on Saturday. We will be analyzing model trends to determine if the Warning needs to be extended on Saturday. Previous discussion...A potentially historic lake-effect snowstorm will continue across far NE Ohio and NW PA tonight through Saturday morning as a long fetch, westerly flow of cold air interacts with near record warm lake temperatures. In terms of the pattern, a closed mid-level low near James Bay will gradually pivot into Quebec through the weekend as the associated broad, deep mid/upper trough continues across the Great Lakes. This will maintain a broad cyclonic flow of cold air and sufficient synoptic moisture across the Great Lakes, with a series of shortwaves oscillating the boundary layer wind fields, causing lake-effect bands to wobble. Lake induced instability will remain strong to extreme through the period, as equilibrium levels reach 20 thousand feet at times with very steep lapse rates. Doppler radar loops this afternoon show that the main band has become wider and more cellular from the western basin of Lake Erie to northeastern Lake, northern Ashtabula, Erie, and extreme northern Crawford Counties. This is due to daytime heating slightly disrupting the boundary layer thermodynamics over the lake and the instability snow showers developing on land. However, the boundary layer flow has been steadily veering more westerly, and this is causing the band to sag slowly southward. Expect that once the sun sets, the band will quickly regain organization and turn into a highly focused, intense plume targeting eastern Lake, NE Geauga, northern/central Ashtabula, Erie, and northern Crawford Counties as a mainly 270 degree flow locks in from this evening through much of the night. The HREF members continue to show the typical south bias, but they have not been terrible this afternoon overall. The RGEM continues to have the best handle on band placement, although a little too far north. With this in mind, opted for a placement between the RGEM and HREF. This is a serious situation because this places the heaviest snow this evening and tonight over areas that have already been hit very hard today. Reports from northern Erie County have been in the 15 to 25 inch range since the snow began late last night, with reports of over 8 inches in 2.5 hours around midday today! Additional snowfall of 18 to 24 inches is likely in northern Erie County through Saturday morning, with locally up to 30 inches. Additional snowfall of 12-18 inches with locally up to 24 inches is expected through Saturday morning in eastern Lake and northern Ashtabula Counties. Just south of this swath, additional amounts of 8-12 inches are expected from about NE Geauga to central Ashtabula Counties. This will place storm totals in the 3 to 4 foot range in the hardest hit areas, with locally up to 50 inches in northern Erie County! In terms of headline decisions, opted to keep ongoing Lake- Effect Snow Warnings through 15Z Saturday for Lake, Geauga, Ashtabula, and Erie and Crawford Counties. Geauga is close, but there is enough confidence that the band will clip the Thompson area this evening and the first half of tonight to bring warning amounts to the far NE parts of the county. Cuyahoga County has the greatest "bust" potential. The band could affect Euclid (extreme NE Cuyahoga) for several hours this evening and early tonight, so kept a small area of additional snowfall near 3 inches. These amounts could be a couple of inches higher or lower depending on how it orients after dark, so there`s a possibility the Advisory may need to be cancelled. If the band orients slightly farther south, then the Advisory is fine. This will be watched this evening. Late tonight and Saturday, the boundary layer flow is still projected to back rather quickly ahead of a stronger shortwave dropping into the Great Lakes. This will start to steadily lift the band northward before sunrise Saturday and through midday. Trends have been for this to happen a little slower, so held onto higher PoPs along the Erie, PA lakeshore through early afternoon, but it will end on the Ohio lakeshore 12-15Z. By mid afternoon, all of the snow should be over the lake as the band reorients into the Buffalo area. This will give a needed break to dig out. Unfortunately, the aforementioned shortwave will move into the southern Great Lakes Saturday night and start to veer the flow more westerly again. This will start to push the band back into NW PA and extreme NE Ohio overnight. There will be stronger boundary layer shear Saturday night, so that will likely make the band more ragged and cellular, but it will start to snow at least moderately along the lakeshores of far NE Ohio and NW PA again. The band will likely be slower than guidance to move back south due to lake aggregate troughing, so slowly expanded PoPs back south and westward. This will take us into part 2 of this lake-effect snowstorm, so see the short term and long term sections for details on that. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... The large and cold cyclonic flow will continue Sunday into Monday but there will be some subtle changes in the low levels which will shift the lake effect snow bands. On Sunday, center of mid level trough will move to just north of New York state in southern Quebec. The low level flow will start out on Sunday from the west-southwest which will keep ongoing lake effect snow bands hugging near the lakeshore area of far NEOH and NWPA through the afternoon. A surface trough will push across the area Sunday night. The low level flow will become more west-northwest Sunday night through Monday night. This change in the flow will shift the potential of lake effect snow bands more into north central and northeast Ohio as well as NWPA. Some of the secondary snowbelt areas will come into play with the lake effect snow potential, including more of the Cleveland metro area. There could also be a Lake Huron connection that develops for NWPA and the Erie PA area late Monday into Monday night. Additional heavy snowfall is very possible for more of the Cleveland area and eastward towards NWPA. Additional winter headlines will likely be needed for some portion of NEOH and NWPA. Areas outside of the Snowbelt will have relatively quiet weather with some passing light snow showers from time to time with little to no accumulations or impacts. Temperatures will be cold and below average Sunday into Monday with highs in the 30s and overnight lows in the upper teens and 20s. && .LONG TERM /TUESDAY THROUGH FRIDAY/... The upper level weather pattern will start to change on Tuesday. The upper level trough will start to pull away late on Tuesday. The low level flow will start out westerly on Tuesday which will push the lake effect snow bands into far NEOH and NWPA during the day. The flow becomes more southwesterly by Tuesday evening and push the lake effect either out into Lake Erie or hugging the lakeshore of far NEOH and NWPA Tuesday night. The upper level pattern briefly will be more zonal by Tuesday night. A strong shortwave trough will dive down through the Great Lakes region on Wednesday with a deepening surface low tracking through the Upper Great Lakes. An area of snow will spread over much of the region by Wednesday morning with a warm front. Snow, briefly mixing with rain at times on Wednesday is expected with light snowfall accumulations possible areawide. As the strong low pressure system passes by to our north, a cold front will move through Wednesday evening. It will become windy Wednesday through Thursday with gusts easily up to 35 mph.The areawide of snow will transition back to organized lake effect snow bands for both the primary and maybe the secondary snowbelt Wednesday night through Thursday night with additional localized heavy snow possible. && .AVIATION /00Z Saturday THROUGH Wednesday/... A heavy and persistent band of lake effect snow will continue to impact ERI airport through tonight, before southwesterly winds push this band north over Lake Erie on Saturday morning. This band has shown signs of re-organizing and gaining strength again this evening and is likely to maintain LIFR conditions with visibilities often around 1/4 mile through most of the overnight. It is hard to tell when improvement may occur, but looking for improvement sometime on Saturday morning. Snow will be in the vicinity on Saturday but likely to push north over Lake Erie. Elsewhere, scattered snow showers that we experienced this afternoon are expected to taper off this evening with drier low level air arriving. At CLE, snow is not likely to impact the terminal while a heavy band remains just a few miles north over Lake Erie. Conditions at remaining airports are generally expected to be VFR through the TAF cycle. Southwesterly winds of 10-12 knots will gust to 20-25 knots through late Saturday afternoon. Gusts may become less frequent late tonight before resuming again on Saturday morning. Outlook...Non-VFR likely in periodic lake-effect snow through Tuesday. The heaviest and most-persistent lake-effect snow in our region is expected to impact the primary snowbelt in far Northeast Ohio and Northwest Pennsylvania. CLE may see light snow accumulations Sunday night into Monday morning. && .MARINE... A large low pressure system north of the Great Lakes will keep winds elevated and rough conditions on Lake Erie this weekend through early next week. Winds this weekend through early next week will generally be from the west 15 to 25+ plus with gusts up to 35 knots at times with organized snow squalls. There might be some slight variation of the westerly flow at times, turning more west-northwest or west-southwest. Waves will remain high especially for the central and eastern basin of Lake Erie over the next several days. Small Craft Advisory are in effect and may need to be extended further in duration over time with no changes in the weather pattern expected through middle of next week. By Wednesday, a strong low pressure system may develop and track across the Upper Great Lakes which will change our winds briefly from the south 20 to 30 knots before returning to west-northwest winds following a cold front. Low water advisory remains in effect into Saturday with the latest water level at Toledo 2.7 inches below the low water datum. The critical water level for safe navigation is 3 inches above the low water datum. Water levels will slowly increase and improve late on Saturday over the western basin of Lake Erie. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...Winter Weather Advisory until 10 AM EST Saturday for OHZ011. Lake Effect Snow Warning until 10 AM EST Saturday for OHZ012>014-089. PA...Lake Effect Snow Warning until 10 AM EST Saturday for PAZ001- 002. MARINE...Low Water Advisory until 1 PM EST Saturday for LEZ142>144- 162>164. Small Craft Advisory until 10 AM EST Saturday for LEZ142-143. Small Craft Advisory until 7 AM EST Monday for LEZ144>149. && $$ SYNOPSIS...Garuckas NEAR TERM...KEC/Garuckas SHORT TERM...Griffin LONG TERM...Griffin AVIATION...KEC MARINE...Griffin
Area Forecast Discussion
National Weather Service State College PA
939 PM EST Fri Nov 29 2024 .SYNOPSIS... * Wind chills will drop as low as the single digits this weekend and continue through the first week of December. * Multiple bouts of lake effect and upslope snow are in store over the next week. * Some minor moderation with high temperatures by the middle of next week, along with a bit more sun and less wind. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Mid evening update. Given the time of day and abnormally warm Great Lakes water temperatures, winds should hold to the southwest, helping aid in keeping the main band of snow off Lake Erie mainly north of our area overnight. There will be still some snow showers around across the far north, and at times across the higher terrain to the south. Thus will keep current products up until 7 AM Saturday morning. Depth of cold air deeper this evening than last evening, which aided in the formation of heavier snow showers earlier today. Temperatures on track, as colder air works into the area. Earlier discussion below. The main snow band over far NW PA and wrn NY is thus far keeping mainly out of Warren/McKean Cos. This has caused thoughts of dropping/downgrading the warning and advy there, but confidence is very low (30pct) that the LES will stay away or continue to be rather lame all night. The latest HRRR actually breaks the one larger band into at least two with one pointed directly into Warren Co. As the air is getting drier, the fluffiness of the snow increases. This will make it easier for the snow to build up. So, we`ll hold the line on those hazards. The LES should lift all north of the CWA in the morning, allowing the warning and advisory to die on time or even be cancelled early/overnight. The wind stays gusty all night, generating wind chills near zero in the highest terrain of Somerset Co, and lower teens in the lowest elevations/cities of the Lower Susq. MinT is a slight challenge with the sky trying to clear over much of the area, but the wind staying up. Will keep them right with guidance for now, which plays the middle ground in the envelope of possible temps. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY/... Mid evening update. While it will be cold this weekend, temperatures far away from record low values one can see this time of year. Hard to believe it is the end of November, November will still average several degrees warmer than normal, even with this shift in the weather pattern. Earlier discussion below. A brief break in SHSN will be accompanied by some really blustery conditions with maxes another 3-5F colder than Fri. The gusty west wind will keep wind chills between 10-15F during the daylight hrs over the wrn mtns, and teens and L20s elsewhere. A potent shortwave trough dives E out of the Rockies and across the OH Valley into the central Appalachian Mountains late Sat night and Sunday. That will generate SHSN for the Laurel Highlands, but mainly Somerset Co. At this point, the moisture looks very limited, and accums will probably be under advy level (widespread 3"), but the tallest elevations and west-facing slopes in Somerset Co could see more. The rest of the area should stay dry and partly cloudy Sat night. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Mid evening update. Potential for snow showers to get further inland across central PA will increase later Sunday into Tuesday, as winds become more northwest. Conditions may moderate a bit by mid to late week, but will still be colder than we have had this fall so far. Week 2 in December will be interesting to see how much mild air can work in from the northwest. Earlier discussion below. Boundary layer flow becomes more west-northwesterly on Monday and into Tuesday behind a departing shortwave which will allow for lake effect snow bands to move into northwestern Pennsylvania. Most guidance suggests that the heaviest snowfall will be confined to Warren and McKean counties. By the middle of the week, flow once again becomes more southwesterly ahead of an approaching low pressure system. Ensembles seem to be coming into agreement that this low will track over the Great Lakes and will bring light snowfall to most of Central PA Wednesday into Thursday. Cyclonic flow remains overhead through the end of the week and will support continued upslope snow showers over the western mountains and lake effect snow over the northwest. Temperatures will remain well below normal through the extended period with highs generally in the 20s and 30s and lows in the teens and 20s. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Snow showers have become more isolated in nature across west- central PA this evening as most large scale lift has moved east of the area. Heavier snow is confined to a wide band of lake effect downwind of Lake Erie, generally staying west and north of BFD. Winds will remain up through the night, with occasional gusts to 25-30 kts. Most of Central PA will be VFR tonight into Saturday, but MVFR clouds are possible at BFD and JST as early as 05z Sat and lasting as late as 21z Sat. However, given the marginally dry airmass, MVFR cigs are not expected during this entire window. An upper level shortwave trough will swing across the OH valley and into the central Appalachian Mountains Saturday night. This feature will likely drop conditions to MVFR and possibly IFR during the daylight hours Sunday at JST, with lower chances of MVFR at the other TAF sites. Outlook... Sun Night-Tue...Continued breezy west winds. Prolonged chances for MVFR/IFR conditions with snow showers across the north and west. Wed...Higher chances for widespread restrictions with snow in a Clipper system. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 7 AM EST Saturday for PAZ004. Winter Weather Advisory until 7 AM EST Saturday for PAZ005. && $$ SYNOPSIS...Dangelo/Banghoff/Martin NEAR TERM...Martin SHORT TERM...Dangelo/Martin LONG TERM...Martin/Bauco AVIATION...Dangelo/Colbert
Area Forecast Discussion
National Weather Service Kansas City/Pleasant Hill MO
556 PM CST Fri Nov 29 2024 .KEY MESSAGES... - Light snow likely tomorrow morning, especially toward central Missouri. - Most areas should receive only a dusting to 1" of snow. - 1" to 4" of snow is possible across central Missouri, primarily along and north of Interstate 70. - Colder than normal temperatures continue into early next week. && .DISCUSSION... Issued at 146 PM CST Fri Nov 29 2024 Current water vapor imagery overlaid with 500 mb heights and winds shows longwave troughing across much of the CONUS with strong northwest flow aloft over the region. The clipper system that will impact us tomorrow morning is currently over southern British Columbia and into northern Washington State. By midnight tonight, it should be over the Front Range, with the vort max and a 65+ knot 500 mb jet streak entering into central Kansas by around 6 am tomorrow, yielding forcing to ascent across the region. Modest theta e advection will yield slightly increased dew points and PWATs, helping to provide enough moisture to develop snow. Light snow will likely begin sometime around 4 to 6 am tomorrow morning, with the prime time still looking like 6 am to noon with the potential for a FGEN enhanced snowband, especially toward central Missouri along and just north of Interstate 70. Even though we are less than 24 hours out, CAM guidance is still relatively varied. The NAM NEST continues to be the most bullish on snow amounts while the HRRR is much less excited. Have trended toward the 12z SPC HREF for snow totals, with a small area of 2-4" possible in the Marshall/Boonville/Moberly areas of central Missouri, and as such a winter weather advisory has been issued for these locations. Elsewhere, a dusting to 1" is likely for most areas (including the KC metro). That being said, just a slight shift in where the FGEN band sets up could have a big impact on where we see enhanced snow totals. Accumulating snow should completely exit our CWA to the east by early afternoon, although some flurries could continue across northern, northeastern, and central Missouri through the afternoon and evening hours. Temperatures tomorrow night are expected to be quite chilly, with lows in the mid teens to lower 20s. Cooler than normal temperatures will persist into Sunday and Monday as we remain beneath strong northwesterly flow aloft on the backside of longwave troughing. Highs for Sunday and Monday are forecast to be in the 30s with overnight lows in the teens. A warming trend is likely to begin Tuesday and continue into the middle of next week, with high temps returning to the upper 40s to mid 50s by Wednesday of next week with dry conditions prevailing. Another shortwave trough is projected to descend out of Canada and into the Midwest on Thursday, sending a cold front through the area and ushering in cooler temperatures for Thursday and especially Friday. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 543 PM CST Fri Nov 29 2024 VFR conditions persist through the evening. Lowered CIGs move in ahead of a passing system which looks to bring -SN Saturday morning. Periods of low end MVFR to IFR are expected. -SN moves out of the area by midday; however, MVFR CIGs linger through the remainder of the period. Winds remain light and variable becoming easterly by midnight and northeasterly Saturday afternoon. && .EAX WATCHES/WARNINGS/ADVISORIES... MO...Winter Weather Advisory from 4 AM to 2 PM CST Saturday for MOZ031>033-039-040-046. KS...None. && $$ DISCUSSION...Williams AVIATION...Pesel
Area Forecast Discussion
National Weather Service Goodland KS
506 PM MST Fri Nov 29 2024 .KEY MESSAGES... - An extended period of dense fog may develop over portions of northwest Kansas and southwest Nebraska Saturday morning, mainly along and east of a line from Benkelman to Colby to Gove City between 3-10 AM CST. - Dry weather continues through next Friday. && .SHORT TERM /THROUGH SUNDAY NIGHT/... Issued at 1239 PM MST Fri Nov 29 2024 Across the Tri State region this afternoon, skies are mainly sunny except for some scattered high cloud west and north. With a surface trough over eastern Colorado, there is a south- southwest gradient over the area around 10 mph, with some isolated gusts around 20 mph. Temperatures are mainly in the 40s with some 30s in the far east. The main weather concern for the short term period will be the potential for patchy freezing fog in eastern portions of the area late tonight into Saturday morning. For the remainder of the afternoon hours, mainly sunny conditions with near to above normal temperatures. Southerly flow will diminish as sunset approaches. Going into tonight, short term guidance brings a backdoor cold front into the CWA by 06z Saturday. This will be followed by a ridge axis nosing into eastern portions of the CWA through Saturday morning before it shifts east. Expecting fog to develop for areas along/east of Highway 25. With the overall track of the ridge axis rolling through mainly areas along/east of Highway 83, have mentioned the best potential for fog formation there. This is close to previous forecast. Overall guidance is mixed as to the strength/extent of the fog, with some down to a mile or less for a good portion east of Highway 25, and some just focusing along/east of Highway 83. With the inconsistency, have focused a 3-6sm swath from Red willow county south and east-southeast into Norton/Graham counties through about 12z-15z Saturday. With temperatures expected to range below freezing during this time, the fog could freeze on elevated surfaces/roadways and pose potential travel issues. This will have to be monitored in later shifts as newer guidance becomes available. For the remainder of the weekend, NW flow aloft with amplified ridging over the west. High pressure building off the Rockies will keep the CWA precip-free. The only thing to monitor will be the potential for more overnight/early morning fog as the ridge transitions over the Plains. Downslope, warming flow overnight saturday should keep fog down, but Sunday night winds will be light/variable as RH increases towards the 12z Monday timeframe. For temps, highs this weekend will range mainly in the 40s area- wide, but Sunday could have some western locales approaching the lower 50s, especially along the Hwy 25/27 corridors. Overnight lows will range in the upper teens to lower 20s tonight and Saturday night, with 20s expected Sunday night. With these expected temperatures, clear skies and some wind, wind chill readings will range mainly in the lower to mid teens. Some locales along/west of Highway 27 may only see readings in the upper single digits above zero towards sunrise. && .LONG TERM /MONDAY THROUGH FRIDAY/... Issued at 1144 AM MST Fri Nov 29 2024 The latest runs of the GFS and ECMWF continue to show persistent NW flow aloft at 500 mb during the period, with a weak shortwave passing north of the area late Thursday into Friday. At the surface, there will be several areas of high pressure passing to the east of the CWA. This will be in between lee-side troughing coming east off the Front Range and through the central Plains. The overall result of these passing through the region will be several shifts from a southerly warm flow to northerly flow. While no precipitation is expected, there continues to be the chance for patchy fog to develop in the east as each surface ridge passes by the area during the overnight and early morning hours, especially next Wed-Thu nights but will be highly dependent on the strength of the wind gradient each night. Also the passage of the aforementioned shortwave looks to only bring some increased cloud cover, for northern/eastern zones. This may hamper fog formation to a degree. For temps, looking for highs on Monday to range mainly in the 40s. Areas along/east of Highway 83 may only see the upper 30s. 50s for Tuesday and Wednesday will give way to a mix of 40s and 50s for next Thursday and Friday. Overnight lows, mainly in the 20s for most nights. Monday night in northeast portions of the Tri State area may see mid and upper teens. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 500 PM MST Fri Nov 29 2024 GLD: VFR conditions are anticipated to prevail through the TAF period. An extended period of dense fog may develop over portions of northwest Kansas Saturday morning.. mainly along/east of a line from Benkelman to Colby to Gove City between 07-16Z. While fog is expected to remain east of GLD.. current and recent runs of the HRRR suggest that fog may be in relative close proximity (within 30 miles). Light/variable winds will shift to the NW and increase to 10-15 knots late Saturday morning (~16Z). Winds will weaken and become light/variable around or shortly before sunset Saturday evening (~23Z). MCK: An extended period of dense fog may develop over portions of southwest Nebraska Saturday morning.. mainly along/east of a line from Benkelman to Colby to Gove City. Sub-VFR conditions assoc/w fog are expected at the MCK terminal between ~07-16Z. LIFR-VLIFR conditions are possible in the ~08-12Z time frame. Fog will dissipate by late morning and VFR conditions will prevail through the remainder of the TAF period. Light and variable winds will prevail through most, or all, of the TAF period. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...None. CO...None. NE...None. && $$ SHORT TERM...JN LONG TERM...JN AVIATION...Vincent
Area Forecast Discussion
National Weather Service Wilmington OH
919 PM EST Fri Nov 29 2024 .SYNOPSIS... Snow showers and flurries are expected tonight in a brisk westerly flow. A disturbance is forecast to bring light snow accumulations Saturday night into Sunday. Drier weather arrives later on Sunday after the disturbance moves east. && .NEAR TERM /THROUGH SATURDAY/... Flurries/ moderate snow showers have continued to push through the region this evening, allowing for a light dusting on roadways/sidewalks/elevated surfaces. Given that this is weakly forced precip in cyclonic flow, there isn`t much guidance to help with end time, however, looking at the HRRR/RAP and NAM 850mb RH... the highest moisture content looks to move east out of the ILN CWA by midnight tonight or shortly after, so have tapered off snow showers around that time. Winds remain elevated overnight, around 10-15 MPH with some 20 MPH gusts. Currently, temps across the region are in the low 20s and feels like temps are in the single digits. Clouds clear out as that moisture moves east and we should end up with mostly clear skies after midnight. Therefore, have tweaked overnight lows a tad lower and dropped them comfortably into the teens area wide as radiational cooling processes will take over. Previous discussion--> Weak boundaries and disturbances embedded in a cyclonic westerly flow are triggering snow showers and flurries from a relatively shallow layer of moisture and instability. Main area of concern is roughly from I-70 south to the Ohio River. This loosely organized band of snow showers is best represented on the HRRR which shows minor accumulations late this afternoon through this evening. Went well above NBM pops for this short duration event. Main impact appears to be brief reductions to visibility with winds gusting over 20 knots in some of the heavier snow showers. Road temperatures suggest that slippery spots will not be common, but conditions could worsen somewhat after sunset. Expect drier weather after midnight when the cyclonic flow may weaken as winds back about 20 degrees. Temperatures will be cold, with lows in the mid and upper teens, and wind chills in the single digits above zero. && .SHORT TERM /SATURDAY NIGHT/... Saturday begins dry with high pressure building to the south. That will change late Saturday afternoon and Saturday evening thanks to a short wave disturbance in the mid level flow. Models have been relatively consistent regarding this system, showing light snow accumulations mainly along and south of the Ohio River. 1 to 1.5 inches of accumulation are indicated by the latest model estimates in those southern locations such as Owenton and Maysville KY, with lesser amounts forecast as we go farther north to Dayton and Columbus. There may be some travel impacts to the southern areas by Sunday morning. Temperatures staying below normal are forecast to rise to the upper 20s to mid 30s Saturday, falling to the upper teens to mid 20s Saturday night. && .LONG TERM /SUNDAY THROUGH FRIDAY/... On Sunday morning, broad troughing will remain in place across the eastern half of the CONUS, with a shortwave moving through the Ohio Valley and into the mid-Atlantic region. The broad trough will dominate the weather pattern through the extended forecast period, with temperatures below normal being the main issue. There may be a brief warm-up heading into Thursday, before cold conditions settle in again for Friday and likely beyond. The Sunday morning snow will be exiting the area by early afternoon, with only light additional accumulations in the southeastern ILN CWA before ending. The next chance for precipitation will be late Tuesday night into Wednesday. After the broad trough finally moves to the east, a brief but notable period of height rises will occur, with theta-e advection -- primarily at 850mb and above. This mid-level forcing will be focused to the north of the ILN area, but it is expected that some precipitation will spread into the region from northwest to southeast. The main issue with this precipitation will be determining the precipitation type. Initially, the boundary layer will be cold enough to support all snow (through Wednesday morning) before some switch to rain occurs where temperatures are able to warm on Wednesday, as the thermal profile switches from an inversion to one with steeper lapse rates. It is not totally out of the question that some chance for light freezing rain could occur with this kind of pattern developing over cold antecedent conditions, but probabilities for this to occur -- on a Day 5 forecast -- remain small. The main story for Wednesday morning at this point is that some wintry precipitation will be possible, but with little confidence in any notable impacts. After this precipitation ends late Wednesday, some additional precipitation chances may come into the picture for the end of the week. This brief warm-up on Wednesday and Thursday will only bring temperatures back to values near normal -- or even maybe just short of normal. By the end of the week, another southward moving cold front will bring a return to temperatures well below normal. Winds are worth noting through the extended period as well. As the mid-week system moves through the area, this will be the period with the tightest pressure gradient, as a surface low moves across Michigan. Current models suggest this will be on Wednesday, with some potential for gusts in the 20-30 knot range. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... Light to moderate snow showers continue to move through the region, primarily affecting the northern TAF sites. These showers continue through midnight, then taper off. Winds remain elevated as we head into the first half of the night, with gusts to 25 knots possible through 02z ish. Then, gusts decrease and we`re left with WNW winds around 10 knots. After snow moves east, conditions improve to VFR for all sites. Clouds clear out and we`ll be left with some scattered cu for the early morning on Saturday, persisting into the afternoon. Winds increase yet again, shifting to westerly around 12 knots, gusting to 25 knots through Saturday afternoon. Clouds begin to thicken and lower as we head into the late afternoon hours Saturday ahead of our next weather maker that arrives Saturday night. For now, have trended this into all TAF sites and included arrival of snow showers, MVFR and IFR CIGs/VSBYs into the extended CVG TAF. OUTLOOK...MVFR/IFR conditions possible Saturday night into Sunday, particularly for sites along/near the Ohio River. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio NEAR TERM...CA/Coniglio SHORT TERM...Coniglio LONG TERM...Hatzos AVIATION...CA
Area Forecast Discussion
National Weather Service North Platte NE
546 PM CST Fri Nov 29 2024 .KEY MESSAGES... - Flurries and light snow are possible tonight into Saturday morning across portions of northern Nebraska. Travel impacts are not expected. - Temperatures will be near normal through the weekend across the southwest and about 10 degrees below normal across the northeast. A warming trend Tuesday and Wednesday as highs return to the mid 40s to mid 50s. Dry conditions are expected. && .SHORT TERM /THROUGH SUNDAY/... Issued at 157 PM CST Fri Nov 29 2024 Northwest low aloft will persist across the Northern and Central Plains tonight through Sunday. Surface high pressure will persist across the Dakotas. A weak disturbance currently embedded in the upper flow in eastern Montana will drop southeast through western South Dakota this evening and northeast Nebraska late tonight. Weak isentropic upglide shown on the 285K surface across southwest South Dakota into north central Nebraska this evening. Some saturation shown up through the 305K surface across southwestern South Dakota through northeast Nebraska overnight, then diminishing quickly Saturday morning. The NAM bufkit sounding shows saturation up through 400mb and periods of weak lift in the minus 10C to minus 20C dendritic layer tonight. This will be across the northeastern counties mainly east of a line from Valentine through Bartlett. Very little QPFs below 0.05" are shown by deterministic NAM and Canadian models, while the GFS and ECMWF are mainly dry. Continuing a slight chance for light snow and mention of flurries across the above mentioned area. Little if any accumulation is forecast, so impacts to travel are not expected. Fog development is likely across portions of southwest Nebraska beginning midnight tonight and lasting through late Saturday morning. The HRRR and RAP are in close agreement on location, including much of southwest Nebraska. Surface low pressure in eastern Colorado this evening will move into south central Kansas overnight, bringing in a weak backdoor cold front and favorable fog formation. Saturday, highs again reach the low to mid 40s across the southwest, while the northeast remains colder in the upper 20s to low 30s. Flurries may linger through mid morning, with winds becoming light west to northwest in the afternoon. Saturday night into Sunday, not changes in the weather pattern as northwest flow aloft continues. Highs will range from the low to mid 40s southwest and the mid 20s to low 30s northeast. && .LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/... Issued at 157 PM CST Fri Nov 29 2024 A backdoor cold front Sunday night will bring slightly colder temperatures on Monday. Highs from the NBM were lowered to the mid to upper 20s northeast to the mid 30s to low 40s west and southwest. Looking ahead to Tuesday through Wednesday, upper ridging across the western U.S. will bring height rises to the Central Plains with westerly downsloping winds as highs return to the 50s west and central. There will be colder air dropping south from the Northern Plains and Great Lakes region Wednesday night into Thursday. Highs cooler Thursday and Friday from the mid 30s northeast to the mid to upper 40s southwest. Current forecast is dry in this extended period as well. && .AVIATION /00Z TAFS THROUGH 00Z SUNDAY/... Issued at 546 PM CST Fri Nov 29 2024 Active weather is expected through tonight with light fog across the south and light snow in the north. At this time, current guidance suggests snow will remain just to the east of KVTN and therefore, it is not in the going TAF forecast. For the patchy fog, development is expected after 06Z mainly across southern Nebraska, impacting KLBF by Saturday morning. Fog is anticipated to remain thin with visibility restrictions only down to 5 miles. Conditions improve by mid-morning giving way to VFR conditions once again. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Kulik