Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/07/22


Area Forecast Discussion
National Weather Service Columbia SC
639 PM EST Thu Jan 6 2022 .SYNOPSIS... A cold front will move through the region tonight with a few showers. High pressure along with cooler and drier air will move into the region for Friday and Saturday. Fair and warmer Sunday ahead of a front that will move through Sunday night and early Monday, providing a better chance of showers. Cool and dry conditions then persist through the middle of next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... At 23z a cold front is approaching the Upstate SC. Warm advection and some limited moisture (shallow) is resulting in a band of mainly light showers in the Piedmont SC and east central Ga ahead of the front. These showers will move through the area this evening but likely diminish since the air mass remains relatively dry...and drier than models suggested earlier. So cut pops back from previous forecast and any qpf will be quite limited. The latest guidance favors the CSRA for qpf where precipitable water may increase to 0.80 inches...so pops higher there. Based on the HRRR and Rap, the front moves through the central Midlands around Midnight. Clearing behind the front with some gusty winds so continued the Lake Wind Advisory...due to warmer water expect mixing. Winds should diminish toward daybreak. The front is progged to be offshore by the early morning hours with skies clearing from west to east as the sun rises. Though the incoming airmass will be much cooler and drier, low temperatures will not completely bottom out due to a well- mixed PBL, compliments of those northwest winds. Overnight mins therefore expected to range from the upper 20s/low 30s along and north of I-20 to the mid 30s toward the coastal plain. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Cold front pushing toward and through the area today will be moving east and away from the area on Friday. Mid-level confluence and subsidence behind the departing shortwave trough will help to clear any additional cloud cover out quickly, and will help make Friday a nice day. Weak surface northeasterly flow will commence, with cold and dry air advection through the day. Surface high pressure will quickly begin to settle into the Mid-Atlantic by Saturday morning. As a result of all of this, Friday will be cooler and drier. Highs may be a tad warmer than otherwise owing to weak downsloping, and this should help to keep us fairly dry at the surface as well. Expect highs ranging from the mid 40s north to the low 50s south. Friday night should be a cold one, but how cold is going to depend on how much winds can fall off Friday night. It looks like it will be a clear night, but with high pressure remaining to our north, I am skeptical that we`ll have ideal radiational cooling conditions. I`ve nudged forecast lows up a bit to account for winds staying in the 3-6 mph range overnight. Still, expect a cold night with lows likely in the 24-30F range. Saturday will be another nice, albeit cool, day. We`ll be underneath surface ridging, and will likely end up in the upper 40s to around 50F for highs again. Saturday night should be a bit warmer as the surface high shifts eastward. This should result in some moisture advection, which will keep our lows in the low and mid 30s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Temperatures will quickly moderate again on Sunday as we continue this roller coaster that we`re on (at least temperature wise). Shortwave ridging from Saturday will quickly shift east as a longwave trough digs into the eastern US on Sunday. This will be associated with a strong Canadian high pressure pushing into the central US. The combination of these two things will result in a strong but quick cold front developing and pushing towards the region by Sunday night. Ahead of this front, widespread southwesterly flow and some compressional warming ahead of the front will likely result in above normal highs in the low to upper 60s. Operational models and ensembles are all in good agreement that this will likely be approaching by 7p on Sunday and push through between 1a and 7a early Monday morning. Ahead of this, guidance suggests a PW plume that will contain values near 200% of normal, which should lead to widespread rainfall developing. Given the quick nature of the front, we won`t see a long duration rainfall event. However, given soundings indicative of warm & moist profiles, we should get efficient rainfall. Current thinking is that everyone will likely see at least 0.25" of rain, with the ensemble means ranging between 0.25" and 0.75". The most rain will likely fall across our northern & western counties closer to the best shortwave trough and forcing. There may be some isolated thunder but nothing widespread is expected given that model soundings are indicating little to no CAPE. Once the front moves in, a cooler and drier airmass will usher in for at least the beginning of next week. NAEFS & ECM indicate that this 1032-1036 sfc high pushing in for next week will be in the 90- 97th percentile for this time of year, suggesting that we`ll have some cooler than normal temps on Monday, Tuesday, and possibly on Wednesday. High temps will likely range from the mid 40s to the mid 50s each day, with Tuesday expected to be the coldest day as the surface high settles in. Ensemble guidance is in good agreement for several runs on placement/timing and strength of this high, leading to above normal forecaster confidence in this solution. Lows will likely be in the mid 20s to low 30s range each night, with Tuesday night likely being the coldest night. It`ll depend on the eventual track of the surface high, but if we are centered underneath the high & get ideal radiational cooling, some areas will likely end up in the low 20s on Wednesday morning. But those details will be ironed out over the coming days. Dry weather is expected after the Sunday night front through the end of the period as low PW air settles in with the strong surface high. High temperatures will likely begin rebounding to near/slight above normal values again on Wednesday and Thursday. && .AVIATION /00Z THURSDAY THROUGH TUESDAY/... Surface low pressure moving by to the north with a cold front pushing through the area this evening. Showers associated with this front will move over the terminals shortly after 00z. With low levels relatively dry, however, widespread restrictions are unlikely. TEMPO MVFR CIGs and VSBYs possible at AGS/DNL but remain unlikely elsewhere. Winds are currently out of the south but will switch to westerly behind the front and increase with gusts between 15 to 20 knots. By early Friday morning wind gusts will decrease with winds remaining out of the NW between 5 to 10 knots with clearing skies. EXTENDED AVIATION OUTLOOK...Restrictions possible Sunday and Sunday night as the next low pressure system and associated cold front cross the region. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...Lake Wind Advisory from 10 PM this evening to 7 AM EST Friday for GAZ040-063>065-077. SC...Lake Wind Advisory from 10 PM this evening to 7 AM EST Friday for SCZ016-018-020>022-025>031-035-037-038-041-115-116- 135>137. && $$
Area Forecast Discussion
National Weather Service State College PA
1000 PM EST Thu Jan 6 2022 .SYNOPSIS... A quick-hitting snowstorm will impact central Pennsylvania through early Friday morning. Blustery northwest winds will produce single digit wind chills in the Alleghenies tonight into Friday and lake effect snow across the northwest snowbelt Friday morning into Friday night. Expect fair weather on Saturday with a period of freezing rain/ice likely Sunday morning. Another period of lake effect snow is likely on Monday along with sub-zero and positive single digits wind chills forecast Monday night into Tuesday. && .NEAR TERM /THROUGH FRIDAY/... Nice snow band easily visible on the radar from Harrisburg to Chambersburg. Already a few 2" reports from the southern tier, and the good band of snow is morphing some right now. The HRRR progs put the band on a pivot over the SErn counties for the next 3-6 hrs. The timing of snow end looks very solid with prev fcsts, but intensity now looks higher/heavier for a few hours between now and 08Z in the SE. Thus, have bumped the snow amounts up 1-2" in that area, which bumps them over winter storm warning criteria of 5"/12hrs. The rest of the area has the forecast rolling along excellently. Snow intensities are as expected there. Bumping Schuylkill Co snow total, too, but they have a 6" criteria, and may be too far north for the best band. Prev... Snow is right on time and is gradually making it down through the dry air at the sfc. As of yet, no heavy snow obs seen in PA, but some going below 1SM. First few hours of the QPF from 18Z runs over the SW have likely been a little high, but this is to be expected with the snow struggling to get to the sfc. With the progression of things so far being so close to the going forecast, and with the newest 18Z guid looking solid, no significant changes are in store for this update. Prev.... Visible sat/regional radar loops show increasing mid-high clouds covering CPA this afternoon with snow spreading northeast across WV. We expect a snow onset time between 5-7PM across the Laurel Highlands/southwest Alleghenies with snow spreading quickly to the northeast through the remainder of the evening. Guidance remains pretty consistent in taking amplifying shortwave ESE from the central High Plains into the lower OH Valley by 00Z Fri before taking on a negative tilt and shifting east to the Mid Atlantic coast. Coastal low pressure consolidates over the southern Delmarva/VA Tidewater around 06Z Fri before rapidly developing as it lifts north toward the New England benchmark. We were keen to make several incremental changes to the previous forecast (which was largely in pretty good shape): 1. A slight increase in snowfall amounts from south to north. 2. Expansion of winter weather advisory north to I-80 corridor 3. Start time adjustments the previous winter wx advisory 4. New winter weather advisory for Warren County (lake effect) The increase in snowfall is supported by the latest WPC WWD, NBM and HREF mean. This pushed totals into the low-end advisory category for most counties along the I-80 corridor. We also considered a winter storm warning for Somerset County with some locations coming in with 6-7 inches. Later shifts can upgrade if needed, but for now we decided on a high-end advisory 4-6". Headline start time adjustments were minimal pushed back 1-2 hours, however the end times may need to be extended as latest hires models keep snow going into the predawn hours Friday. Band of moderate snow should take aim on the southern Alleghenies this evening into early tonight, then pivot and shift toward the I-81 corridor. Increasing FGEN forcing has us concerned that heavier snowfall amounts may occur near and southeast of I-81 which is a feature that most hires model guidance appears to be honing in on. The updated WPC WWD also captured this feature in the latest cycle, so that will be something to watch closely this evening. Overall, max snowfall rates should remain in the 0.50 to 1 inch range with the highest probability 1hr rates >1" over along and southeast of I-81 from ~ 1-6AM or during the predawn hours. Snow character will be a dry/fluffy snow with temps in the 20s and SLRs in the 12-18:1 ratio based on a blend of WPC and NBM. The lower ratios are shaded toward the southeast part of the Keystone State. Northwest winds will increase late tonight through early Friday morning with gusts 20-25mph over the Laurels by daybreak. The blustery winds combined with temps falling into the upper teens will produce single digit winds over the western mtns by sunrise. Synoptic snow should taper off from west to east during the predawn hours. However, the increasingly cold and gusty west- northwest flow will result in developing lake effect snow showers across the Allegheny Plateau late tonight. Low temps will range from the mid teens over the Alleghenies to the mid 20s in the southeast; but it will feel colder when factoring the wind. && .SHORT TERM /FRIDAY NIGHT/... Cold and blustery conditions expected on Friday. Model soundings support max gusts between 30-35 mph with the highest winds around 40 mph on the ridgetops across the southwest Alleghenies. Model indicate some very dry air flowing south across the Grt Lks Friday. However, steep lapse rates, high inversion heights, lowering DGZ, possible Huron connection and snow/water ratios near 20:1 should result in several inches of fluffy snow across the snowbelts of Warren County. We were keen to upgrade to a winter weather advisory with 2-4" of lake effect snow expected. Locally higher amounts are possible especially in the northwest part of the county. Max temps don`t recover very much from morning lows with a narrow diurnal range expected. Highs Friday trended colder and now range from the upper teens in the Laurels to around 30F in the southeast (first day this winter of sub-freezing temps across the CWA). It will feel even colder when factoring the wind with max ApparentTs in the single digits and teens. Expect LES to taper off with clearing skies and diminishing winds Friday night as high pressure builds into CPA. A cold night with lows in the single digits to mid teens. && .LONG TERM /SATURDAY THROUGH THURSDAY/... Fair weather and light wind is expected Saturday, as surface high builds across the state. Model RH profiles support abundant sunshine and GEFS 2m temp anomalies suggest highs will remain a few degrees below average, mainly upper 20s to low 30s. Main focus of this period is near the beginning as a favorable setup for a light mixed precipitation and icing event is slated for late Sat night/Sunday, as warm front lifts across the region Sat night into Sunday followed by weak shearing cold front. Precipitation is not expected to be heavy, but the slow moving decaying frontal zone sagging across the region with ambient cold air in place at the low levels and widespread warm layer aloft promises to result in a mix of mainly sleet and freezing rain, with many central PA valley locations likely to remain near freezing through Sunday afternoon as precipitation diminishes. A warm front will push through the region Saturday night into early Sunday. Latest guidance suggests up to 0.25"+ of QPF with the approach of the front, again mostly falling as an icy mix of sleet and freezing rain. With antecedent 1030 hPa cold high pressure system in place on Saturday (temps in the 20s Sat night), ground temperatures after midnight Sat night and Sunday morning will be supportive of ice accretion. Air temps will slowly warm through the day Sunday, but ground temperatures may lag behind and stay below freezing for a couple of hours longer. Expect to need additional time for travel on Sunday. Colder, drier conditions are likely behind the front early next week, with any snow showers likely limited to the typical lake effect snow belt. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... MVFR cigs holding over the NW this morning and will likely remain through this afternoon. Later in the afternoon and evening, a storm system will bring snow to all airfields. Snow will reach JST and AOO first by 22z, then spread north and east through the evening. Reductions in vis and cigs likely in SHSN. Snow will be light for the most part, but heavier bands of snow remain possible along the south /JST, AOO, MDT, LNS/. Snow will be out of most places by Friday morning, with lake effect snow showers at BFD for Friday. Outlook... Fri...Lingering snow showers and restrictions possible north and west. Becoming VFR elsewhere. Sat...Generally VFR. Sun...Lowering conditions bring restrictions in rain or wintry mix. Mon...VFR across the southeast, chance of snow showers across the north and west. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 6 AM EST Friday for PAZ051>053- 058. Winter Weather Advisory until 2 AM EST Friday for PAZ024>026- 033>035. Winter Storm Warning until 4 AM EST Friday for PAZ036-056-063- 064. Winter Weather Advisory until 4 AM EST Friday for PAZ019-027- 028-049-050. Winter Storm Warning until 6 AM EST Friday for PAZ057-059-065- 066. Winter Weather Advisory from 5 AM Friday to 1 AM EST Saturday for PAZ004. && $$ SYNOPSIS...Steinbugl NEAR TERM...Dangelo/Steinbugl SHORT TERM...DeVoir/Steinbugl LONG TERM...Fitzgerald/Dangelo/Colbert AVIATION...DeVoir
Area Forecast Discussion
National Weather Service Des Moines IA
543 PM CST Thu Jan 6 2022 ...Updated for the 00z Aviation Discussion... .DISCUSSION.../Tonight through Thursday/ Issued at 204 PM CST Thu Jan 6 2022 Key Messages: -- Bitter cold again tonight, turning milder Saturday -- Chillier air, gusty winds behind front Saturday night/Sunday -- Return to milder conditions middle of next week -- Dry forecast Details: Shallow and thin cloud streets oriented parallel to the low level flow exist over much of Iowa with manual adjustment to the RGB Day Snow Fog or Day Phase Cloud Distinction making these a bit easier to see. These clouds were able to produce some flurries/ice crystals this morning and even this afternoon with recent reports at ALO of HZ/5 mile visibility. Forecast challenge tonight will be the amount of cloud cover that will move over central Iowa, particularly northeastern Iowa/forecast area. 12z HREF/latest National Blend of Models (NBM) shows thinning mid-level clouds over this area with a more likely low/mid cloud deck over the western/southwestern half of the state. Similar to previous shift, continued to lower temperatures below initial NBM guidance to 25th percentile of available guidance with a touch of the 10th percentile of NBM. This morning, wind chills around MCW, EST, and AXA fell to between -33 to -38F for multiple hours. The winds tonight fortunately will be decreasing and much lighter to start than last night as high pressure moves over the area. Wind chills will still drop below -30F from Winnebago to Franklin to Black Hawk counties and northeast from mid-evening to a few hours before sunrise. However, as winds become calm with the center of the high, the wind chill values will have risen from their minimums by 6am. Therefore, will continue with the current advisory area and time. The high pressure will also keep dry air in the low levels meaning that the low level warm air advection that produces light snow over Nebraska will move across Iowa dry. Temperatures will begin to increase on Friday as mid-level ridging builds into the state along with the aforementioned low level warm air advection. This will continue and be more noticeable on Saturday with highs in the 30s as the ridge moves off to the east. Moisture will be drawn toward the region on breezy southerly winds ahead of a broad trough moving across western North America. Evidence of this moisture is seen in cross sections from the RAP and NAM with the latter not bringing the low level saturation as far north at this time. However, with warmer air moving over the snowpack and dewpoints nearing freezing as well, will have to monitor for fog potential. The trough will have a strong surface low moving across the Canadian prairies with a cold front draped to the south to a weaker surface low over the central Plains. This front will move through the state Saturday evening with gusty winds developing from the northwest and bringing a shot of chillier air. Moisture is limited ahead of this front and while the GFS/GEFS is dry across our area, there are enough ensemble members from the ECMWF and CMC with light QPF over southeastern Iowa to keep the low PoPs from NBM. OTM BUFKIT sounding Saturday evening does show that there is no ice introduction aloft so drizzle/freezing drizzle could result before drier air sweeps in. However, most of the precipitation will be shunted to the east and south that this should overall not be a concern or impact. As the trough moves to the east on Sunday, a shortwave trough embedded on the backside of the trough may bring light precipitation to parts of the region Sunday night. Initial NBM is dry and think that is still a good route based on the 6z/12z ensemble guidance with just a few members showing light QPF somewhere in the region, not necessarily even Iowa. Rising heights and eventually southwesterly flow will allow milder conditions to return next week to above normal by middle of next week. && .AVIATION.../For the 00Z TAFS through 00Z Friday evening/ Issued at 543 PM CST Thu Jan 6 2022 Widespread VFR conditions are expected during the forecast period with winds becoming light overnight. VFR ceilings are expected across the area on Friday with surface winds becoming southeast. Visibilities are expected to remain unrestricted. && .DMX WATCHES/WARNINGS/ADVISORIES... Wind Chill Advisory until 9 AM CST Friday for IAZ015-023-035>039- 048>050-061-062-075. Wind Chill Advisory until 9 AM CST Friday for IAZ004>007-016-017- 024>028. && $$ DISCUSSION...Ansorge AVIATION...Cogil
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
947 PM EST Thu Jan 6 2022 .UPDATE... The evening update focuses on lake effect snow trends for the Thumb shoreline, especially for Huron county where a Winter Weather Advisory remains in effect. Inland snow shower activity continues to fade as the near stationary front weakens/fills during the late night. Locations north of I-69 picked up around an inch of new accumulation since noon mainly due to persistence of the frontal zone aided by a west to east ripple of low pressure. Mid evening radar and surface visibility support the diminishing trend as the front and associated convergence weakens while developing a disconnect from Lake Michigan. Filling of the surface trough over Lower MI leads to the wind veering more northerly over Lake Huron on a line into the Thumb after midnight. Bulk parameters for lake convection look really good as the fetch becomes more favorable, especially for the Huron county shoreline. Canadian/Exeter radar illustrates more than adequate lake instability is already in place as a broad mesovortex rides west to east within the surface front toward Goderich. This feature is replaced by multiple bands into Huron county as a result of the northerly flow transition. HRRR model soundings show impressive convective depth pushing 700 mb or near 10 kft with deep supersaturation during the 1 AM to 4 AM time period. There are also hints of inverted trough development over the lake in model data across the range of resolutions that suggest a trend toward a dominant band is possible. This could happen on the shoreline before moving back toward mid lake or it could stay offshore and spare high end accumulation. The evening update holds the line on Advisory level snow accumulation in the 3-6 inch range within about 5 miles of the shoreline between Port Austin and Harbor Beach. This allows for accumulation during the early multi-band phase and also a heavier burst that could materialize during the dominant band transition. A weaker larger scale pressure gradient develops by early morning which offers a more convincing offshore trend through mid and late morning. && .PREV DISCUSSION... Issued at 653 PM EST Thu Jan 6 2022 AVIATION... A wide range of aviation conditions is in place this evening as a cold front settles slowly southward through the region. Restrictions are driven primarily by concentrations of snow showers fed by Lake Michigan and focused eastward within the frontal zone. Borderline IFR/MVFR in the MBS to FNT area is then expected to follow the front southward toward PTK and the DTW corridor by late evening before moving into Ohio after midnight. NW flow continues behind the front and is favorable for some breaks in low cloud coverage toward sunrise. A general scattered sky condition Friday morning becomes broken VFR in the afternoon. Low level wind begins a backing trend toward the southwest which carries some residual lake effect clouds in from Lake Michigan Friday evening. For DTW... VFR transitions to MVFR this evening as a cold front moves slowly through the terminal region. IFR visibility could occur briefly during this time in a heavier snow shower with a dusting of accumulation. The front moves south after midnight with some breaks in the clouds developing toward sunrise. DTW THRESHOLD PROBABILITIES... * High for ceiling at or below 5000 ft through tonight. * High for snow as the precip type. PREV DISCUSSION... Issued at 330 PM EST Thu Jan 6 2022 DISCUSSION... A cold front positioned near the I-69 corridor will sag south through the remainder of the area late today into this evening. Convergence along this boundary is enhanced by the lake aggregate trough present over the Great Lakes and this should allow for a temporary flare up of lake effect snow showers during the late afternoon and early evening as this front releases south. Given current low level trajectories as gleaned from regional radar and visible satellite imagery early this afternoon, expect the most concentrated snow shower activity to focus from around I-69 south to M-59 with activity dissipating with time into the evening as it shifts south into the I-94 corridor. Powdery accumulations will be limited to half an inch or less in general, especially M-59 north, with perhaps an inch in localized spots. Lake effect snow shower activity over the Thumb has shifted east during the day, but expect banding to pivot back onshore later this afternoon and especially this evening as low level flow swings abruptly to the north by 00z. Inversion depths are forecast by 3km- NAM to be on the order of 6-7kft with most of this layer within the dendritic growth region, so snow shower intensity should support the continuation of the advisory for Huron County. The main question will be how long any activity that does develop remains onshore tonight. Confidence in the duration of snowfall is too low to consider an upgrade to a warning at this time. Additional snowfall tonight looks to maximize along the immediate Lake Huron shoreline from Port Austin to Harbor Beach where an "uncertain" 3 to 5 inches of snow may fall. Cold conditions will persist into Friday with lake effect activity diminishing and pivoting east of the area. Temperatures will range in the upper teens to lower 20s. A brief moderation in temperatures will then occur from late Saturday into early Sunday as a shortwave ridge builds into the region between the exiting upper trough now working through the area and then next stream of Pacific shortwave energy. Expect temperatures to climb into the lower 30s during this time frame with a chance of light snow showers as this shortwave crosses the area. MARINE... Northerly winds gusting to around 20 knots across Lake Huron is promoting elevated wave heights leading to hazardous small craft conditions. A Small Craft Advisory remains in effect across the nearshores from Outer Saginaw Bay to Port Huron into early tomorrow morning. Winds turn more northwesterly by tomorrow. This wind direction will continue to favor some elevated wave heights across northern portions of the Thumb through tomorrow afternoon though wind gust potential is expected to remain mostly under 20 knots. On Saturday, pressure gradient increases across the central Great Lakes between an Appalachian high pressure and a low pressure system moving from western Ontario into the Hudson Bay. This will lead to increasing southerly flow and the potential for gales across portions of Lake Huron. Frontal boundary is driven through the region early Sunday leading to winds out of the west that will have potential to gust to around 30 knots. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...Winter Weather Advisory until 7 AM EST Friday for MIZ049. Lake Huron...Small Craft Advisory until 4 PM EST Friday for LHZ421-441>443. Gale Watch from Saturday morning through Saturday evening for LHZ361>363. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ UPDATE.......BT AVIATION.....BT DISCUSSION...DG MARINE.......AA You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Northern Indiana
857 PM EST Thu Jan 6 2022 .SYNOPSIS... Issued at 836 PM EST Thu Jan 6 2022 Moderate to heavy lake effect snow will continue for portions of far southwest Lower Michigan and far northwest Indiana through Friday morning before rapidly diminishing in the afternoon. 5 to 10 inches is likely in these locations with locally higher amounts over a foot in northern Berrien county. Light snow showers or flurries are expected elsewhere. It will be cold, with wind chill values of zero to ten below tonight. A wintry mix is possible Saturday night into Sunday morning. && .UPDATE... Issued at 836 PM EST Thu Jan 6 2022 Our moderate to heavy lake effect snow band has arrived, just sinking southward into the northern portions Berrien/Cass Counties in Michigan as of this writing. Issued an SPS to highlight this band for the two counties, with 1-2 inch per hour rates and visibilities of 1/2 mile or less expected. Accidents and poor road conditions have been reported thanks to the falling/blowing/drifting snow. One video submitted to our Twitter account from near South Haven looked like we had front row seats on the Millennium Falcon riding through space-so that should give everyone an idea of how driving in this stuff will be (not recommended). As for forecast changes haven`t made any significant updates. Still opting to keep the current headlines as they are given the persistent trend in model guidance to keep the band further eastward/north-which is in line with the current observations. It seems the eastward extent to the band is pretty limited/light as far as impacts go (as of this writing), so no plans to expand eastward into Lagrange county or upgrade any of the advisories yet. However, will continue to monitor trends in the event things get more aggressive when the broader trough arrives. Reports of snow fall and road/visibility conditions are appreciated. Thank you to those who have submitted them thus far. && .SHORT TERM...(Tonight and Friday) Issued at 242 PM EST Thu Jan 6 2022 Challenging lake effect event the big problem this aftn. As addressed yesterday, intense lake effect snow found through central MI along sfc trough under upper low through cntrl lower MI. This curves n/nw into dominant single band mid lake west of Ludington and the feature to watch going into this evening. Sfc trough, currently along a GRR to DTX line, will break down quickly late aftn as parent upper low finally opens/kicks east through lake Huron. As that occurs, upstream lake band should intensify significantly as large scale lake aggregate thermal troughing takes over. This intense band expected into sw MI this evening and hold near steady state into Friday morning before eventually lifting out in the aftn. Some typical e-w waver implied in most model guidance and expected given modulating background/intense thermal trough. While far wwd solutions like HRRR can not be ignored given how warm lake sst are, hedged east given greater multi-model concensus. Heaviest potential accumulations likely invof nrn Berrien and adjacent Van Buren/Cass where isold 15" amounts look quite plausible especially in light of model derived 1-2"/hr snowfall rates at peak intensity. 5 to 10 generally expected otherwise in the warning, and up to 5 in surrounding advisory counties, perhaps a bit more in far northern St Joseph but weakening cloud bearing flow should stall srn extend/feed of heavier accums there. Will keep as is with prior headlines. Cold otherwise inland with diminishing gradient of which will keep wind chills aoa -10 late tonight/Fri morning. && .LONG TERM...(Saturday through Wednesday) Issued at 242 PM EST Thu Jan 6 2022 Intense warm advection develops late Fri night as arctic ridge breaksdown in response to incoming large scale upper trough. Sufficient moisture advection looks to hold off until evening before activating precipitation but fair amount of timing spread exists yet in 12Z guidance. Nevertheless warming aloft along with sfc temps around freezing and cold ground temps likely to lead to a skating rink on area roads and which may not necessarily improve Sun morning as cold air poised to wrap in quickly. Thus given colder 12Z consensus solution added a bit more ice again. Another arctic ridge quickly follows though the wrn lakes Mon with another round of lake effect by late day into Tue yet shifts ewd ahead of another system digging through James Bay Wed. && .AVIATION...(For the 00Z TAFS through 00Z Friday Evening) Issued at 638 PM EST Thu Jan 6 2022 Expect predominantly MVFR to IFR conditions at KSBN tonight, and VFR to MVFR conditions at KFWA. Expect westerly winds at KFWA with light snow showers diminishing to maybe flurries (if anything) overnight. Expect mid-high end MVFR ceilings improving to VFR. Otherwise, the main focus this issuance is how much will KSBN be impacted the ongoing lake effect event. An intense band of snow north of South Haven, MI as of this writing will gradually shift southward through the evening, with 1-2 inch per hour snow rates and blowing/drifting snow thanks to blustery W-NW Winds behind an incoming trough. A majority of the guidance keeps this heavier band north of KSBN (barely), but it`s possible that KSBN is impacted. For now went more conservative with ceilings and visibilities based on observations from the site today, but expect the worst conditions between 6-10z ish if the band does impact the site. It is also possible the band stays further north, in which case conditions would be better than forecast. && .IWX WATCHES/WARNINGS/ADVISORIES... IN...Winter Weather Advisory until 10 AM EST Friday for INZ004-005. MI...Winter Storm Warning until 10 AM EST Friday for MIZ077-078. Winter Weather Advisory until 10 AM EST Friday for MIZ079. OH...NONE. LM...Small Craft Advisory until 4 PM EST Friday for LMZ043-046. && $$ UPDATE...MCD SYNOPSIS...MCD/T SHORT TERM...T LONG TERM...T AVIATION...MCD Visit us at www.weather.gov/iwx Follow us on Facebook...Twitter...and YouTube at: www.facebook.com/NWSNorthernIndiana www.twitter.com/nwsiwx www.youtube.com/NWSNorthernIndiana
Area Forecast Discussion
National Weather Service New Orleans LA
657 PM CST Thu Jan 6 2022 ...EVENING UPDATE... Main focus on this evening update was paying close attention to the frontal position and its forward progression, ingesting high- res short-range guidance to match obs trends. Utilized the recent 22Z HRRR for temperatures and dewpoints through tonight, as well as a blend of the HRRR and 90th percentile NBM for surface winds/wind gusts. Some low clouds are spreading in behind the front per latest GOES-16 Night Fog Channel Diff, with ceilings around 1 to 1.5kft AGL, generally aligned with the 925mb front. Approached MinT`s carefully given persistent CAA through the morning hours, as well as areas of low-clouds spreading southeast reducing radiational cooling potential. Guidance does reduce gradient winds somewhat towards daybreak, but not completely enough which will allow mixing to persist. With all that said, aimed near or just slightly above deterministic NBM to account for these processes and their interaction with temperature trends. Additionally, removed the mention of frost as well, but can`t rule out some light areas for a few hours across SW MS or the Pearl River Basin, east to the MS coast within any protected areas. Clouds will try to break up during the morning hours, but will likely continue to see cold air stratocumulus clouds lingering over marine areas. Temperatures look on track glancing at latest guidance/trends, leading to a chilly winter-like day ahead for everyone as we close out the week. KLG && PREV DISCUSSION... /issued 357 PM CST Thu Jan 6 2022/ SHORT TERM (Tonight through Tuesday)... A band of showers continues to move across the area as the cold front moves through the area. Although we have a little moisture advecting into the area as well as the frontal passage moving through, we still lack a lot of the necessary instability needed to produce actual thunderstorms. With this in mind, mainly just showers are expected to continue through early evening tonight. Updated the POPs and Wx grids for the current and next few hours to reflect the showers and removed the threat of lightning and thunderstorms as we have not seen any so far and confidence is low that we will see any lightning develop over the next several hours. Cooler air will penetrate the area behind the front causing temperatures to drop well below climo to near and below freezing in most areas with lows tonight/ Friday morning in the low 30s. Daytime temperatures will see an almost 20 degree difference from today`s temps and are expected to be chilly with highs barely reaching mid 50s. Friday night temperatures will be chilly once again with lows in the upper 40s to low 30s. Winds look to really lighten up Friday night so wouldn`t be surprised if temperatures drop more closer to freezing with the help of continued strong CAA. Otherwise, no weather expected on Friday. Saturday temperatures will see an increase with highs in the low 70s/ upper 60s as the ridge shifts starts to build in warmer air is advected into the area. A slight repeat of fronts is expected Saturday night as a cold front is forecast to move through the area some time Saturday evening. The only difference with this front is the substantial moisture and dynamic force return allowing for increased chances of rainfall across the CWA on Sunday and development of one or two thunderstorms. Persisting warm air advection will allow for seasonably warm temperatures to continue through the day with highs in the mid/upper 70s Sunday but will be overcame by cooler air mass. /TDB/ LONG TERM (Sunday night and beyond)... A cooler and more dry air mass will be the driving factor as winds begin to shift and become more northerly through the night on Sunday as a result of strong cold air advecting into the region. As a surface high ridges into the area Monday, any lingering s/ts will move east and out of the area by daybreak and increasing clearer skies and cooler temperatures will be expected. Monday night/Tuesday morning expect near freezing temperatures with low temperatures dropping 10 degrees or more from the night before as lows dip down into the mid to low 30s. Light NE winds are forecast Tuesday with mostly clear skies and drier weather conditions. Tuesday night will be another chilly night with lows dipping into the low to mid 30s yet again. Upper level high pressure will remain in place through at least mid week so drier conditions are expected to continue. /TDB/ AVIATION (00Z TAF DISCUSSION)... Focus for this evening and tonight will be a frontal boundary passing through the entire area followed by increasing surface winds and direction change bearing 330 to 350 (NNW), transitioning to 350 to 010 (N) through the late evening/overnight hours. Winds remain elevated through tonight and into early tomorrow. Other impacts include low CIGs building in behind the front ranging 1 to 1.5kft already passing KBTR to KMCB, spreading southeast. Included approximate timing for all terminals ahead of the low clouds in area TAFs tonight, with prevailing MVFR to intermittent IFR conditions into daybreak. Expect a steady transition to VFR for all terminals through mid to late morning from north to south as low clouds dissipate, with occasionally breezy north winds persisting through the day, transitioning to 050 to 070 (NE) in the afternoon hours. KLG MARINE... North winds near 15 to 20 kts continue and are forecast to shift more easterly tonight near 25kts as the cold front moves into the coastal waters. A Small Craft Advisory is in effect for tonight through tomorrow afternoon to account for these windy conditions. Going into the weekend, expect another front to enter the coastal water bringing similar SCY conditions to today`s expected late Saturday through Sunday. Additional headlines after the current one may be needed for the next round of windy conditions this weekend. /TDB/ && .PRELIMINARY POINT TEMPS/POPS... MCB 31 53 38 69 / 0 0 0 20 BTR 34 55 43 70 / 0 0 0 40 ASD 35 58 41 71 / 0 0 0 30 MSY 42 55 49 71 / 0 0 0 40 GPT 36 55 43 67 / 0 0 0 10 PQL 34 55 40 68 / 10 0 0 10 && .LIX WATCHES/WARNINGS/ADVISORIES... LA...None. GM...Small Craft Advisory until noon CST Friday for GMZ530-532-534- 536-538-550-552-555-557-570-572-575-577. MS...None. GM...Small Craft Advisory until noon CST Friday for GMZ532-534-536- 538-550-552-555-557-570-572-575-577. && $$
Area Forecast Discussion
National Weather Service Marquette MI
914 PM EST Thu Jan 6 2022 .UPDATE... Issued at 913 PM EST THU JAN 6 2022 Per hourly HRRR trends and latest model runs, will trend snow amounts up an inch over snow belt regions prone to NNE flow. Bands could briefly become heavy at times as convergent areas move up the Keweenaw early tonight and over eastern portions of Marquette County. This would potentially push localized totals up into the 8- 10" range over those snow belts. Currently, radar mosaic continues to show persistent LES bands with temperatures ranging from the single digits over the interior west to teens over the remainder of the UP. Updated grids have been sent. && .SHORT TERM...(This evening through Friday) Issued at 351 PM EST THU JAN 6 2022 Precip has transitioned over to pure LES within the NNE to N wind belt regions. The bands are stretching fairly far inland, although do lighten up beyond the initial upsloping enhancements. This trend will continue well into the overnight period, with indications of localized heavy bands setting up within convergent areas, such as near the Porkies as well as within the eastern portions of Marquette County. Orographic lift will assist in bumping up snow amounts within the higher terrain, especially wherever the heaviest bands set up. Again though, the focus shouldn`t be on amounts so much as it should be on impacts. Even though the amounts will be much lighter overall as compared to the last 24 to 48 hours, adding more snow onto already snow-covered roads will cause hazardous driving conditions in addition to reduced visbys within moderate to heavy bands. The other weather-related concern for tonight will be the incoming frigid temperatures expected. Wind chills tonight will easily be sub-zero for much of the U.P., especially in the interior west. The limiting factors will be whatever LES-related cloud cover that persists overnight as well as the general/typical moderation provided by Lake Superior. The winds themselves look to generally remain near/below 10 knots overnight. Actual low temps will drop into the negative teens in the far west, sub-zero interior west, low teens above zero along Lake Superior, and single digits elsewhere. In other words, quite a bit of variation in lows is expected depending on the location, but with the overall picture of coldest temps in the west/interior. Highs tomorrow will be fairly reminiscent of today, topping out in the teens for most, perhaps only single digits in the far west, and around the 20 degree mark near and along lakeshores. .LONG TERM...(Friday night through Thursday) Issued at 310 PM EST THU JAN 6 2022 Overall, the long-term pattern will be cooler than normal leading to LES (primarily for NW wind snow belts) and drier than normal weather elsewhere. A warm front brings a chance of light snow and warmer temps on Saturday ahead of an arctic cold front Saturday night. Temperatures fall through the day on Sunday and Sunday evening through Tuesday morning look particularly cold with widespread below zero temps likely, especially during the morning hours. Bitter cold combined with 10-15 mph winds should result in dangerous wind chills, especially Monday morning. A clipper system could invigorate LES on Tuesday and perhaps bring light snow to inland locations too, but this seems less likely than it did yesterday. Otherwise, a trend toward warmer and drier than normal weather appears likely going into the second half of next week. Starting at 00z Saturday, low temperatures could occur early in the night until WAA brings clouds and increasing southerly winds in well before sunrise. Southerly winds become gusty by Saturday morning, especially for portions of the Lake Superior shoreline favored by downsloping winds. WAA forces light snow showers on Saturday, but most locations pick up less than an inch or two. Lake effect snow seems like a good bet for south to southwest winds snow belts off Lake MI on Saturday. Lake-850 mb delta-Ts around 18 to 20C supports generally moderate LES potential, especially considering LES is expected to be transient as WAA continues during the day on Saturday. Other than the snow chances above, Saturday appears to be the warmest day of the next week with temperatures warming to near or above 20F across the entire UP. The warm-up is brief since the next arctic cold front quickly pushes east across our CWA Saturday night between ~06z and ~12z Sunday. Thus, Saturday night into Sunday also follows a non-diurnal temperature curve with max temps likely to occur before sunrise on Sunday. Temps then fall into the single digits and teens by Sunday afternoon with below zero wind chills across the CWA by Sunday afternoon. Breezy winds continue through Monday as temperatures fall below zero resulting in potentially dangerous wind chills, especially Monday morning. The coldest temperatures of this arctic blast seem likely Monday night when winds diminish and some breaks in the cloud cover are possible. If light winds and clear skies materialize then readings colder than -20F are possible across the interior west on Tuesday morning. Considerable uncertainty remains for Tuesday and beyond as a series of low-amplitude shortwaves dive southeast across the CWA. The clipper previously slated for Tuesday could still occur, but 12z model guidance suggests it may track across Ontario instead. There is decent agreement amongst the various models for a rapid warm up to above normal temperatures by Wednesday thanks to downslope flow off the Rocky Mountains. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 658 PM EST THU JAN 6 2022 Conditions continue to be the worst at KIWD at this time where LIFR will be the predominant flight category into tonight. Elsewhere, expect fluctuation between IFR and MVFR as lake effect snow persists into tomorrow in the NNE flow. Winds though will fortunately only be in the 5 to 10 kt range through the TAF period, eventually backing to the WSW tomorrow afternoon. A return to VFR levels is probable by tomorrow afternoon. && .MARINE...(For the 4 AM Lake Superior forecast issuance) Issued at 407 PM EST THU JAN 6 2022 Winds on Lake Superior stay below 20 knots tonight through Friday. Next gale event looks to get going with southerly gales to 45 knots Friday night into Saturday, mainly east half. Northwest gales to 40 knots develop Sat night and continue into Sunday night. Freezing spray continues to be an issue for most of this forecast with the stronger wind and cold temperatures especially starting on Saturday night. Cold temperatures and gusty winds persist through Tuesday morning. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until 6 AM EST Friday for MIZ004-005. Winter Weather Advisory until 9 AM EST /8 AM CST/ Friday for MIZ002-009. Lake Superior... Gale Watch from late Friday night through Saturday evening for LSZ248>250-265>267. Lake Michigan... Gale Watch from late Friday night through Saturday evening for LMZ248-250. && $$ UPDATE...TDUD SHORT TERM...lg LONG TERM...EK AVIATION...TDUD MARINE...EK
Area Forecast Discussion
National Weather Service Mount Holly NJ
954 PM EST Thu Jan 6 2022 .SYNOPSIS... Low pressure over the Southeast will lift to the northeast towards the Mid-Atlantic tonight, then intensifies east of New Jersey on Friday before departing. High pressure builds in from the west Friday night and moves offshore Saturday night. A front approaches on Sunday and crosses the region Sunday night, followed by an Arctic front Monday night. Arctic high pressure builds into the region Tuesday, then departs on Wednesday. Another front passes north of the region Thursday. && .NEAR TERM /THROUGH FRIDAY NIGHT/... A burst of light snow has passed through the western suburbs of Philadelphia and Berks county, and is moving through the Lehigh Valley. Will not make significant changes to the forecast with this update, as a coating or so has fallen from this. But it will bear watching. HRRR continues to indicate heaviest snow across much of New Jersey. Otherwise, the main focus for this period continues to be low pressure system expected to bring snow tonight into early Friday. The forecast guidance is now in good agreement tracking low pressure over the SE US north and east off the N.C coast to a position south of Cape Cod by 12z Friday. Going through the overnight is when things get interesting. Clouds thicken through this evening with precipitation overspreading the area SW to NE late this evening into the overnight (mainly after 10 PM or so) as the deepening low pressure system tracks up the coast. This will be a mostly snow event except over southern DE and south coastal NJ where we still think there will be sleet and rain mixing in at times, especially at the onset. This will keep amounts lower here. The main change with this update is that we`ve issued a Winter Storm Warning for most of central and southern NJ as confidence has grown that there will be swath of higher snowfall amounts here, with upwards of around 6 inches or so under a heavier band setting up. Challenge is that these higher amounts probably won`t even include these entire counties as the axis of heaviest snow will likely be just south of the Turnpike but away from the coast extending roughly from Cumberland Counties NE through Monmouth Counties. Strictly speaking, this will be a marginal event in terms of reaching Winter Winter Storm Warning criteria but given the timing leading up to and into the morning rush, impacts could be high. Also, since it will be fast moving, most of the snow will be falling within just a few hours with rates potentially reaching 1-2 inches per hours. Farther north over eastern PA and over most of Delmarva we are still forecasting a general 2 to 4 inches of snow. Heading into Friday the snow will quickly wind down from west to east through the mid morning as the deepening low races NE with sunshine even developing by afternoon. However in the system`s wake winds will strengthen out of the NW with gusts of 20 to 30+ mph expected by afternoon. This may cause some issues with blowing snow though it should be noted that the strongest winds will be near the coast where it will be a wetter snow. Lows tonight will be in the 20s to low 30s and these temps won`t increase too much for Friday due to the NW winds / cold advection behind the low. Highs will be mostly in the upper 20s to mid 30s...coldest north and mildest south. For Friday night, winds gradually diminish due to relaxing pressure gradient as the low moves away and high pressure starts to build towards the region. It will be a very cold night though with lows mostly in the teens. Saturday will then be dry and cold as the high crests over the area. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... High pressure centered over West Virginia and Virginia on Saturday will gradually slide east through the day, and will be off the Virginia/North Carolina coast by Saturday evening. High pressure continues to track offshore Saturday night, and return flow sets up behind the departing high. Sunny and cold on Saturday with highs in the upper 20s to low 30s. These highs are around 10 degrees below normal. A cold front approaches Saturday night. Clouds increase after midnight. Prior to midnight, however, with clear skies and light southerly winds, expecting strong radiational cooling conditions. Low temperatures will drop into the teens and 20s in the evening, and then temperatures will hold steady and slowly rise through the night as those clouds spread east. Based on latest models trends, precip should hold off until after daybreak Sunday. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Warm air advection aloft will be underway on Sunday as southerly flow increases between an approaching cold front and high pressure offshore. Light precip develops in the morning over the far western zones. Surface temperatures will remain below freezing through the morning, but temperatures above 950 mb will warm to +5C. As a result, there is a chance for a prolonged period of freezing rain Friday morning for areas west of the Delaware River, generally in the southern Poconos, Lehigh Valley, and down into the Delaware Valley. Temperatures in Philadelphia proper and areas east should be above freezing by the time rain arrives, and then temperatures warm to above freezing for all but the southern Poconos by Sunday afternoon. Based on forecast QPF, generally expecting up to 1/10 inch of ice accretion. Highs on Sunday will range from the low 30s in the southern Poconos to the mid and upper 30s otherwise north and west of the Fall Line, and in the low to mid 40s south and east of the Fall Line. Southern Delmarva will get into the mid and upper 40s. Cold front works its way through the region Sunday night and precip tapers off from northwest to southeast. A bit more wintry weather is possible as it winds down. A stronger Arctic cold front then passes through the region Monday afternoon. Models indicating strong Lake Effect Snow well north and west of the local forecast area, but if the trajectory is good enough, it is possible for some streamers to make it to the far northern zones. Behind that front, the coldest air of the season will spread into the region. Lows Monday night will drop into the single digits and teens, and then highs on Tuesday will be in the teens and low 20s. Will undercut NBM max Temps on Tuesday by several degrees as it looks to be quite cold. This cold snap will be brief, as the Arctic high slides offshore Tuesday night and Wednesday, and return flow ushers a milder air mass into the region. Temps rebound by 10-15 degrees on Wednesday, and then closer to normal levels on Thursday. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...VFR initially, then CIGs lower to MVFR by 06Z/07Z, then quickly lower to IFR thereafter. IFR VSBYs in light to moderate snow with occasional LIFR conditions. Light NW winds, becoming N around 10 kt. Moderate confidence overall. Snow at PHL 4-5 inches expected. Friday...IFR/LIFR CIGS/VSBYS in the 12Z to 15Z time period in snow, then rapid improvement from SW to NE thru the midday. NW winds 15-20 kt with 20-30 kt gusts in the afternoon, which may produce some BLSN that was included with the latest TAFS. Outside of any VSBY restrictions for BLSN, VFR expected thru the afternoon. Moderate confidence. Outlook... Saturday through Saturday night...VFR. Light N winds Saturday, then light S winds Saturday night. Moderate confidence. Sunday through Sunday night...Sub-VFR. FZRA at KRDG/KABE and possibly KTTN Sunday morning and RA elsewhere. Precip changes to plain RA in the afternoon. A brief period of wintry weather is possible Sunday evening as precip winds down. Conditions improve to VFR Sunday night. S winds 5-10 kt, becoming NW late Sunday night. Low confidence. Monday...VFR. NW winds 10-15 kt with gusts to 20 kt. Moderate confidence. Tuesday...VFR. NW winds 5-10 kt. Moderate confidence. && .MARINE... Winds over our northern zones diminish into early this evening but then winds ramp again late tonight associated with the coastal low. Gale conditions are expected on most of the waters beginning Friday morning. The upper Delaware Bay should stay below gale force, but gusts to 30 kt are expected there. Windy conditions will continue through the day Friday then diminish Friday night. Outlook... Saturday through Saturday night...Lingering SCA conditions in the morning, then sub-SCA conditions. Sunday through Monday...SW winds increase to 15-20 kt with gusts up to 25 kt. Winds shift to the NW Monday morning. Seas build to 3-5 feet. A SCA will likely be needed. Tuesday...NW winds 15-20 kt with 25-30 kt gusts. A SCA will likely be needed. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Winter Weather Advisory until 10 AM EST Friday for PAZ054-055- 060>062-070-071-101>106. NJ...Winter Weather Advisory until 10 AM EST Friday for NJZ001- 007>010-012-015-023>026. Winter Storm Warning until 10 AM EST Friday for NJZ013-014- 016>022-027. DE...Winter Weather Advisory until 10 AM EST Friday for DEZ001>003. MD...Winter Weather Advisory until 10 AM EST Friday for MDZ012-015- 019-020. MARINE...Gale Warning from 6 AM to 10 PM EST Friday for ANZ431-450>455. Small Craft Advisory from 4 AM to 10 PM EST Friday for ANZ430. && $$ Synopsis...MPS Near Term...Fitzsimmons Short Term...MPS Long Term...MPS Aviation...Fitzsimmons/MPS Marine...Fitzsimmons/MPS