Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/26/22


AREA FORECAST DISCUSSION
National Weather Service Eureka CA
250 PM PDT Fri Mar 25 2022 .SYNOPSIS...A cooling trend will continue tomorrow with clearer weather along the coast. A low pressure system Sunday will bring gusty southerly winds and rain, mostly to Mendocino and Lake counties. Isolated showers and cool weather will linger into early next week followed by a return to above average temperatures. && .DISCUSSION...Warm, dry weather has continued in the interior this afternoon with temperatures in the low to mid 70s. This is a few degrees colder compared to yesterday. With air cooling aloft, the marine layer was able to quickly lift and scatter out before noon today, allowing coastal temperatures to warm to around 60. The marine layer is expected to remain weak tonight with only thin, patchy fog. The upper level ridge currently over the area will continue to gradually progress eastward into the weekend. This progression will allow the cooling trend to continue in the interior, helping keep the marine layer weak and scattered for Saturday. A deep cutoff low centered over central California is projected to approach the coast early Sunday. High clouds will start moving in ahead of the low by late Saturday. An occluded front curving around the system will bring gusty southerly winds (20 to 30 mph) along the coast and on ridges, particularly in Mendocino and Lake counties. Rain associated with the front currently looks heaviest Sunday afternoon with scattered showers lingering into Monday. The NBM shows 0.4 to 0.7 inches for Mendocino and Lake Counties with only 0.1 to 0.2 inches further North. NBM 4.1 however shows a 60 to 70% chance of some southern totals reaching above 1 inch, but deterministic models are consistently lower than 1 inch. This difference likely reflects high sensitivity of rainfall amounts to the low`s exact track. Over the next 24 hours, high resolution models like the HRRR should bring better detail. Less rain is expected to linger into Monday, though increasing instability (up to around 100 J/Kg) could allow for isolated lightning, mostly in the high elevations of eastern Lake and Mendocino. Though both the NAM and GFS this afternoon are putting a stable layer around 600 mb, which would put the equilibrium level below -20 C. Such a stable layer, should it materialize, would reduce the overall thunder risk. Instability and cold air advection behind the front will help bring cool weather and generally little marine layer formation along the coast early next week. Temperatures in the interior will cool behind the front with mild highs in the low 60s. All cluster ensemble members show at least weak high pressure building in mid next week, bringing another round of mild temperatures and likely some coastal stratus. About 30% of the clusters show the high quickly breaking down into a weak trough, perhaps bringing more light precipitation with other ensemble members showing more zonal flow. Regardless, about 80% of the clusters show a stronger ridge beginning to cover the area by next weekend. /JHW && .AVIATION...A trough is slowly approaching the west coast. Surface winds have started to switch to the south in the north. The southerly winds will slowly across the area tonight. These southerly winds and cooler temperatures will weaken the marine layer. This should keep skies mainly VFR tonight. Saturday some mid level clouds will move into the northern portion of the area, but these are expected to be around 4,000 to 5,000 feet. MKK && .MARINE...An upper level trough is approaching the area and this is spreading southerly winds across the waters. They have not reached Humboldt Bay or Buoy 46022 yet but are expected to tonight. It will take until nearly Saturday afternoon for the remainder of the waters to see southerly winds. The northwesterly swell has dropped to around 4 feet at 12 seconds, but this is expected to increase tonight to around 6 to 7 feet at 13 seconds. This swell is expected to persist through the weekend. Saturday night these southerly winds will start to pick up. Models are showing an area of surface low pressure approaching the Mendocino coast and then turning towards the south before it approaches the coast. Models are showing a fairly big difference in the strength of this low. The GFS has it bottoming out around 987 MB while the NAM only drops it to around 993 MB. As a result the GFS is putting 30KT while the NAM is slower and only showing 22 KT. A growing number of models are trending toward the stronger solution which would yield gale force gusts, but the ensembles show an even wider range of possible solutions so confidence is not high enough for a gale watch. These winds are expected to build wind driven waves to around 9 feet at 7 seconds. In addition to these wind driven waves there will be a mid period swell of 5 to 8 feet 12 to 14 seconds moving into the waters. Models northerly winds will start to spread across the area as high pressure builds in. These are expected to increase more slowly than sometimes reaching 20 kt by late afternoon. Northerly winds are expected to persist through the remainder of the week. Wednesday a weak system passes by to the north, but this is only expected to diminish the winds slightly in the morning. Thursday and Friday northerly gales are possible. Thursday the ENP is showing another northwest swell around 8 feet at 15 seconds building into the waters. MKK && .EKA WATCHES/WARNINGS/ADVISORIES... CA... None. NORTHWEST CALIFORNIA COASTAL WATERS... None. && $$ Visit us at https://www.weather.gov/eureka Follow us on Facebook and Twitter at: https://www.facebook.com/NWSEureka https://www.twitter.com/NWSEureka For forecast zone information see the forecast zone map online: https://www.weather.gov/images/eka/zonemap.png
Area Forecast Discussion
National Weather Service Grand Forks ND
1005 PM CDT Fri Mar 25 2022 .UPDATE... Issued at 1003 PM CDT Fri Mar 25 2022 Forecast going along fine. Narrow zone of clouds from Langdon to Wahpeton is dropping slowly south...clear east of this area into western MN, then west edge of stratocu around low to our east near Roseau to Park Rapids. High pressure well to our northwest over northern Saskatchewan with ridge western ND. So pressure gradient will remain enough overnight to keep winds on the gusty side. Colder air moving in as well with lows in the single digits to teens on track. UPDATE Issued at 703 PM CDT Fri Mar 25 2022 Wind advisory has expired on schedule at 00z. NW winds are slowly diminishing and will continue to do so thru the night, but some gusts 25 mph range still will occur as sfc gradient between departing low and incoming high will remain tight. Skies clearing as well but some clouds will hold tonight. Lows kept the same as see no reason to change them at this time. && .SHORT TERM...(This evening through Saturday night) Issued at 308 PM CDT Fri Mar 25 2022 Short term impacts continue to be related to strong winds this afternoon, with a decreasing trend through early evening (northwest to southeast). Shortwave trough is transitioning east, while tight surface pressure gradient and deep post frontal mixing has continued to support strong winds across our CWA. There has been a decreasing trend over parts of the Devils Lake Basin, and this matches where the 850 MB wind max on RAP is also showing signs of decreasing, so while mixing is still deep winds may not be as strong aloft and advisory type conditions may improve this afternoon northwest to southeast (a bit earlier than current advisory timing). Even where winds aloft in the 40-45kt range linger (our south and east) loss of daytime heating and low level decoupling should put an end to stronger winds. I don`t want to cancel just a few counties early at this stage unless we start to see a much larger downward trend, but I could see us trimming some counties early as winds aloft continue to decrease in our north. Snow showers continue to be reported near Lake of the Woods which is close to the the mid level trough axis, however a drier/more subsidence air mass aloft behind this axis is starting to shift east and any of these lingering showers should start to dissipate by late afternoon. Colder temperatures aloft and mostly clear skies late tonight should result in colder temperatures ranging from the single digits to teens for lows, and highs may struggle to warm out of the teens across our north of Saturday (may still remain near freezing in our southwest aided by sunny skies/exposed dark soils/heating. Arctic high pressure is shown to slide south over our region by Saturday night and even colder temperatures become possible, with colder locations in our north and northeast possibly dropping below zero. There is a strong consensus (based on NBM 25/75th ranges) that regardless of cloud redevelopment most locations will at least be in the lower teens to single digits by early Sunday morning. .LONG TERM...(Sunday through Friday) Issued at 308 PM CDT Fri Mar 25 2022 Main challenge for this forecast period is the potential for a springtime winter storm near midweek. For Sunday into Monday...Cool surface high pressure is in place across the region with lighter winds in a weaker pressure gradient. Meanwhile, the upper level pattern indicates northwest flow aloft as the upper ridge is in place over the intermountain west. Return flow kicks in late Sunday into early Monday as the surface high pressure shifts east. The upper level ridge also builds and increased thicknesses support a warming trend to start the week. By Tuesday...a pattern shift begins to take place as the upper levels suggest more of a split flow regime. The southern stream digs in over the southwestern part of CONUS and the northern stream shows digging as a stronger short wave moves across Montana. The expectation is that by Wednesday, southwest flow aloft becomes the predominant feature, and a series of upper level disturbances will induce cyclogenesis along the main boundary. Although models are in general agreement regarding the placement and movement of this system, the wild card remains the interaction between the northern and southern streams in determining the system track and resultant precipitation type. For now, the ECMWF and Canadian models are trending closer with respect to placement of the features, and would tend to favor lower precipitation amounts. However, the GFS tracks a bit faster and favors a larger precipitation shield. Something that should not be overlooked is the persistence of the system over the Great Lakes. As the upper level trof becomes more negatively tilted as the storm progresses, expect the system to linger in the region longer and the potential for significant precipitation amounts. While reasonably confident of the evolution of the system, the bottom line is that the event is still several days away and will && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 703 PM CDT Fri Mar 25 2022 NW winds to diminish but remain in the 15-25 kt range much of tonight and more north 12 to 25 kts Saturday. Scattered to ocnl BKN CU this evening becoming predominate later tonight and Saturday. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. $$ UPDATE...Riddle SHORT TERM...DJR LONG TERM...Hopkins AVIATION...Riddle
Area Forecast Discussion
National Weather Service Green Bay WI
1041 PM CDT Fri Mar 25 2022 Updated aviation portion for 06Z TAF issuance .SHORT TERM...Tonight and Saturday Issued at 238 PM CDT Fri Mar 25 2022 The latest RAP analysis and satellite/radar imagery show a digging strong shortwave moving southeast over eastern Minnesota and into western Wisconsin early this afternoon. An arcing band of rain and snow is moving east and across northeast WI ahead of the shortwave. Meanwhile a cold front is moving into eastern Wisconsin, with gusty northwest winds, snow showers, and colder temps occurring behind the front. As low level lapse rates steepen in the cold advection zone, a few relatively stronger snow showers are possible south of Highway 29 over central Wisconsin this afternoon that could rapidly drop visibilities to 1/2 mile and produce gusts in excess of 35 mph. Warm surface temps in the middle will likely mitigate the brief higher precip rates on area roadways. Focus of this forecast is precip trends and potential impacts, including from the gusty winds. Tonight...With loss of daytime heating and forcing from the shortwave passing southeast of the area, snow shower activity will be diminishing early in the evening. However, the deformation zone on the north and northwest flank of the upper cyclone will return south and likely provide northern and eastern WI with light rain and snow. Accumulations should remain minor, and remain up to an inch across the northwoods. The falling temperatures below freezing along with residual liquid on roadways from todays precip could lead to slippery spots developing on untreated roadways. In addition, northwest winds will become strong and gusty with gusts to 35 mph. With conditions supportive for ice shoves on the east shore of Lake Winnebago, will continue to highlight the potential in the HWO. Saturday...Gusty northwest winds in cold advection will continue into Saturday. Most precip should have ended across the region with the exception of far northern WI in the lake effect snow belt and possibly into east- central WI. Otherwise, widespread of cloud cover in the morning will give way to increasing sunshine from southwest to northeast. Temps will be well below normal and range from the middle 20s to middle 30s. .LONG TERM...Saturday Night Through Friday Issued at 238 PM CDT Fri Mar 25 2022 A fairly broad upper ridge will keep quiet conditions in place for the first few days of the extended period. As this ridge progresses across central CONUS, an upper trough is expected to dig into the desert Southwest finally culminating in a fairly strong weather system that could bring plenty of precipitation back to the region in the middle to late next week. Saturday night through Monday...Northeast flow aloft will bring in a period of quiet conditions in terms of precipitation, but winds could remain a bit gusty. A fairly tight pressure gradient aloft will keep some stronger winds in place above the surface, which could mix down at times through Sunday night. At the surface, high pressure and a fairly cool air mass will keep temperatures below normal Sunday, before gradually coming back to normal by Monday as return flow increases. High temperatures Sunday will be in the 20s and lower 30s before moderating to mostly 30s and few lower 40s on Monday. Rest of the forecast...Models still differ on how exactly to handle the system for next week, but most have some precipitation developing late Tuesday as isentropic upglide begins with the surface warm front to our south. Overrunning precipitation is then expected Tuesday into Wednesday as the main surface low comes northwards into the Great Lakes region. This will be a relatively broad and slow moving system, with wrap around precipitation continuing through the end of the work week. Stuck with the blended solution for now, which would bring a mix and snow into the region Tuesday into Wednesday, before a wider spread of precipitation develops, with snow towards northern Wisconsin and rain towards southern Wisconsin. Depending on the details of the track, the p-types may end up looking fairly similar to this past Tuesday and Wednesday. Stay tuned!. && .AVIATION...for 06Z TAF Issuance Issued at 1041 PM CDT Fri Mar 25 2022 A strong upper-level system will bring MVFR ceilings and scattered snow showers to the area during the overnight hours. The snow showers are expected to end late tonight, with improving flying conditions expected Saturday through Sunday. Strong northwest winds could gust to 20 to 30 knots at times overnight. Winds will remain breezy on Saturday but gusts will subside somewhat during the afternoon. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Uhlmann AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Grand Rapids MI
1023 PM EDT Fri Mar 25 2022 LATEST UPDATE... Update .UPDATE... Issued at 1023 PM EDT Fri Mar 25 2022 Temperatures are still in the upper 30s at this hour and precipitation remains mostly rain. Cold air will be pouring in overnight, with readings dropping below freezing across the bulk of the area between roughly 3 am and 8 am. Still expecting the rain showers to change to snow showers, with some locally heavy bursts possible under the upper low which tracks across srn Lwr MI overnight. Some areas will see an inch of snow accumulation by morning, even well inland from Lk MI due to the lift related to the upper low. It would not be too surprising if we get a few reports of more than an inch as latest HRRR guidance is suggesting up to 1/3 inch of QPF from 06Z to 12Z. That bullseye is actually located around Lansing where upper low lift may be maximized overnight (NE quad, pivot point). Other QPF maxima are noted in Mason/Oceana Counties as well as in Van Buren Co where NW flow lake enhancement will be in play. Expect slick/slippery travel to develop late tonight due to the combination of snow showers and the drop in temps, and will highlight this change in a Special Weather Statement. && .DISCUSSION...(This evening through next Friday) Issued at 351 PM EDT Fri Mar 25 2022 - Strong Cold front brings rain to snow then snow accumulates There are two cold fronts heading our way. The first one comes through early this evening with an area of rain showers. This is followed around midnight with a stronger cold front that changes to rain to snow and brings in some of the coldest air for this late in the season since 2015 (high high of 31 on 27th of March 2015 at GRR and MKG, 30 at LAN, 32 at AZO) . Anyway this is a closing off 500 to 300 mb low and is nearly closed off at 700 mb. Due to the dynamics of this system, even through it does not have Gulf moisture the strength of the lift will help make up for that so we should still see between .1 and .3" of QPF in about 12 hours as this comes through this evening. The heaviest QPF will be on the northeast side of the track of 700 mb sort of closed low, which would be east of US-131. There is impressive lift in the DGZ on that side of the system tonight. It will be to warm for snow the start but it should cool off enough by say 9 to 10 pm for snow to mix in with the rain. The secondary cold front brings the below freezing air to the surface and that of course changes all the precipitation to snow. Of course by the a lot of the QPF already occurred. Even so there should be enough moisture left to bring around an inch of snow to a good part of the CWA by morning. Areas north and east of GRR could see up to 3 inches (better lift and in colder air sooner). Once the system snow is done we then get lake effect snow showers until the deep cold air exits the area. That does not happen until Sunday afternoon or so. This will mean, on Saturday and maybe to some extent even Sunday afternoon we will have convective instability. It is more obvious on Saturday through. We actually have EQL near 5000 ft (which would be meaningless for summer convection) but when your -15c at 850 you will get vigorous snow showers into the evening. That will impact the entire CWA. We will also get the favored northwest flow snow showers Saturday night into Sunday morning. That could bring a few inches into Van Buren, Allegan, Mason and Ocean Counties (Muskegon typically misses out on the snow from this wind direction). - An Unusually Cold Airmass will chill our weekend and bring snow Helping high temperatures below freezing for high temperatures after the 25th of March is unusual. Since 1980, between the 25th and the first of April GRR, LAN, MKG and AZO have had had highs below freezing 3% of the days in that time period. Again the last time was 2015 on the 27th, prior that we have there was a 3 day period from the 23rd to the 25th with highs in the 20s. You then have to go back to 2001 for the next event. So again, this is very unusual for this time of year. However the models have been very consistent with forecasting 850 temperature below -12 all day Sunday and keeping the 1000 mb temperature below freezing. My 20 years of data at GRR tell me if the 1000 mb temperature is below freezing at GRR, the air temperature any time of the day or night or any time of the year will also be below freezing. The NAM has the 1000 mb temperature below freezing at GRR from 1 am Saturday through 8 am Tuesday. So, yes we have a good chance of having highs at or below freezing Saturday and Sunday, Monday is even possible! - Next system is the middle of next week Currently we have parade of 500 mb closes upper lows over the north Pacific from Asia to North America (actually there are 3 of them). The next in the parade move onshore of North America late in the weekend. This system gets out into the central Plains midweek. Here is the problem through, the cold air has all it can do be dislodged. That means when that system gets far enough east to bring us southerly flow from the Gulf (early Wednesday morning) we get a large area of freezing rain over most of Michigan (both the GFS and ECMWF for several model runs now). If that is not enough, then the surface system deepens rapidly as it charges north to northern MN on Wednesday (getting to below 980 mb). That means we get a good surge of warm and moist Gulf air. This could mean strong to severe storms Wednesday PM or early Thursday. Of course the cold air comes back behind the system so we could see more snow. This system is nearly a week out so we have time to watch it but it would seem we could see several days of impactful weather from this. Precipitation amounts should be on the order of an inch so that could be an issue too. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 757 PM EDT Fri Mar 25 2022 MVFR generally prevailing tonight as rain begins mixing with snow by 03Z then changing to all snow toward 06Z. However occasional IFR conditions will occur, and some LIFR vsbys cannot be ruled out either after 06Z in any of the heavier bursts of snow. Winds gusting up to 30 kts out of the west. Snow showers lingering on Saturday and again MVFR is expected to be the predominate condition. However brief IFR vsbys still possible if/when any heavier snow showers pass through. Winds will continue gusting to 30kts, out of the northwest. && .MARINE... Issued at 351 PM EDT Fri Mar 25 2022 As all that cold air heads into this area with all that mid level dynamic support you just know there will be gale force winds over Lake Michigan (good model support) so we have a gale warning for tonight into Saturday afternoon. Note that the system midweek has much storm force winds forecast with it! && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Gale Warning until 8 PM EDT Saturday for LMZ844>849. && $$ UPDATE...Meade DISCUSSION...WDM AVIATION...Meade MARINE...WDM
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1101 PM EDT Fri Mar 25 2022 .UPDATE... Issued at 1101 PM EDT FRI MAR 25 2022 Lightning has been occurring upstream this evening, as far southeast now as Owen County. The NAM shows surface to 625 mb LI`s (around the -20C level) being negative where it`s been happening, with the negative LI`s potentially making it into the northeast part of the JKL forecast area shortly. Have added a slight chance of thunder. With brisk flow aloft and a cold atmosphere, have also included wording for gusty winds and small hail. UPDATE Issued at 852 PM EDT FRI MAR 25 2022 Have blended evening obs into the forecast, without any appreciable change. UPDATE Issued at 544 PM EDT FRI MAR 25 2022 Light precip has already started to break out, so have moved up the mention of precip earlier in the forecast. && .SHORT TERM...(This evening through Saturday night) Issued at 320 PM EDT FRI MAR 25 2022 Latest RAP analysis shows one weak shortwave has moved through the area and is heading off towards the Mid-Atlantic region, while another wave is starting to pivot down from the upper midwest. A surface low is just north of the upper Great Lakes, with a frontal boundary stretching down through the midwest. Overcast and cool this afternoon across Eastern KY with temps generally in the middle 40s. W/SW winds will continue to be breezy with occasional gusts of around 20-25 mph. The cold front will approach the area late tonight and cross the area overnight into Saturday morning, while the upper level shortwave will pivot down to northern sections of the OH valley overnight. Scattered showers are initially expected late tonight and overnight, with some snow starting to mix in as the colder air filters in. Overnight low temps will be in the lower to middle 30s. The upper level wave will continue moving SE on Saturday towards the Mid Atlantic, while a secondary cold front will approach from the NW. Scattered rain/snow showers will continue during the morning into the afternoon, especially over far E/NE sections of the forecast area. Most areas won`t see any meaningful snowfall accumulations, however a light dusting or so is possible at locations over 2k ft in elevation. W/NW winds will also be gusty on Saturday, especially from mid morning through the afternoon hours. Expect gusts of 20-30 mph, with some higher gusts at the ridges. Went a bit cooler than guidance for high temps, with afternoon highs in the upper 30s to lower 40s (mid 40s near the TN line). Precip comes to an end by late Saturday, although some lingering stubborn flurries may last a bit longer over eastern Pike. The secondary cold front will start to cross the area overnight. W/NW winds will relax to 5-10 mph overnight, but over most areas will stay up enough to prevent any frost formation Sunday morning. There will however, be a chance for some patchy frost in some of the sheltered valleys. Overnight lows will be in the mid to upper 20s. .LONG TERM...(Sunday through Friday) Issued at 407 PM EDT FRI MAR 25 2022 Models are in decent agreement when it comes to the overall pattern through the extended, especially in the early portion of the extended. We begin Sunday with an amplified pattern across the CONUS. East Kentucky lies under northwesterly flow aloft as a trough sits over eastern Canada and New England, and a large ridge dominates across much of the western half of the CONUS. The western ridge edges eastward into the early part of next week as a trough, with an embedded low, digs down over the Pacific coast. As is typical, more differences begin to emerge later in the period around the middle of the week. The amplified trough works across the Plains and Mississippi Valley, before moving over our region near the end of the period. Deterministic models do vary some around the details of smaller scale features and timing, but the overall pattern is fairly well agreed upon, and has support from ensemble means. At the surface, the main feature of interest is the system that organizes over the Plains, supported by the deep trough aloft. A warm front gets lifted across the area through late Tuesday, leaving us solidly in the warm sector Wednesday. As the system travels northeast towards the Great Lakes Thursday, it`s associated cold front is dragged across the region, before it eventually exits late Thursday. Similar to the upper level pattern, this overall setup is fairly well agreed upon, but the details, specifically timing, still show some variability within deterministic solutions. Regarding sensible weather, we start the period dry, but also colder than normal as we remain under the persistent northwest flow aloft. Highs Sunday and Monday range generally from the mid/upper 40s to low 50s. Lows Sunday night sink down into the low to mid 20s. Lows don`t drop quite as much monday night, but are still chilly in the low to mid 30s. As the warm front crosses the area Tuesday, we see a bit of a warm-up and a possible gradient in highs across the area. However, where this gradient sets up will depend on the speed of the warm front, which has yet to be nailed down. We could also see some precipitation with this warm front Tuesday, with the best chances in our north and east. Stayed near the NBM, but will note the GFS was a bit more bullish with the PoPs with this front, so will monitor with future updates. Temperatures take a substantial jump Wednesday as our area see`s strong southwest flow while we sit in the system`s warm sector. Our chance for more moderate rainfall comes with the approach of the cold front late Wednesday night. The best of the precip moves through by Thursday morning, but rain chances linger into the day. Have included thunder for portions of the area Thursday afternoon as of now, but how the timing of the front works out could work to limit how much instability and thunderstorm activity we see. Much of the area then sees drier and cooler conditions behind the front`s passage to finish out the work week. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) ISSUED AT 852 PM EDT FRI MAR 25 2022 Largely MVFR conditions (due to ceilings) were present at the start of the period. The main exception was in the southwest portion of the forecast area around KSME and KEKQ, where low end VFR ceilings prevailed. Very light rain and showers were also ongoing. The status quo is expected until late tonight. After about 06z, Clouds will decrease, especially over the Cumberland Basin. Further northeast, ceilings will remain, but will rise. Showers will also become more sparse. The end result will be improvement to VFR area wide by around 10Z, with VFR conditions then persisting for the remainder of the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...CMF LONG TERM...HAS AVIATION...HAL
Area Forecast Discussion
National Weather Service Louisville KY
957 PM EDT Fri Mar 25 2022 .Forecast Update... Issued at 950 PM EDT Fri Mar 25 2022 Isolated to scattered showers continue across the Ohio Valley underneath the left exit region of a 500mb speed max. Very cold 500mb layer (observed soundings between -30C and -20C) has resulted in steep low level lapse rates, combined with a pocket of 100 J/kg of MUCAPE across central IN, has allowed some scattered convection near IND to bring increased winds down to the sfc. RAP analysis suggests this CAPE and a pocket of 35kt Effective Bulk Shear will advect across northern KY in the next few hours, which could result in a few instances of lightning flashes and gusty showers. Decided to increased thunder grids to 10% across our northern CWA, though currently leaving weather type as just rain showers. By tomorrow morning, lingering showers across our northern half of the CWA could become a light rain/snow mix, but no impacts are anticipated at this time. && .Short Term...(This evening through Saturday) Issued at 155 PM EDT Fri Mar 25 2022 Things are pretty quiet across the CWA at this hour, outside of a few blips on radar dropping in from SW Indiana. Expect steady W winds through the remainder of the day, with some gusts up in the 20 to 25 mph range at times. Given extensive cloud cover and the steady cold advection, highs are only expected in the upper 40s and low 50s across the area. Water vapor imagery currently shows a couple of disturbances of note. The first is over eastern TN, and about to lose any influence over our area. Perhaps a very light shower could still affect our SE for another hour or two. Otherwise, the main shortwave of interest is up over Minnesota at this hour, and will quickly dive into our area by later this evening and into the overnight. Ahead of this feature, we`ll see scattered to numerous rain showers develop on steepening lapse rates. We may see some small hail with some of the evening and overnight showers due to fairly steep low level lapse rates, and freezing levels only around 2500-3000 feet. The first wave of showers from roughly 8 PM to 2 AM EDT, should all be rain with surface temps still in the low to mid 40s. However, as we get toward Saturday morning, additional scattered showers across our NE CWA could be a rain/snow mix, or all snow for a period through mid to late morning. The rest of Saturday looks dry and cloudy for most of the area. Given an expansive stratus deck and gusty NW surface winds (good cold advection continues), we`ll see highs not getting out of the 40s for much of the area. In fact, look for low to mid 40s for most. Our far SW could be on the outside of the cloud shield, and have a better shot at more sun and highs in the 50s. .Long Term...(Saturday night through Friday) Issued at 1:55 PM EDT Fri Mar 25 2022 Saturday Night - Monday Upper northwest flow will push a large surface high from Canada towards the Ohio Valley. This positions the CWA in the path of the high`s anticyclonic winds, resulting in cold air advection and cool temperatures. Sunday and Monday highs will only reach the mid 40s to mid 50s. On the bright side, expecting lots of sunshine on Sunday. A few more clouds arrive for Monday. Monday Night - Tuesday Night As the aforementioned surface high passes east of the CWA, surface winds become easterly as a 35-40 knot 850mb low level jet advances towards the area from the southwest. Isentropically lifting is expected to cause light precipitation to begin expanding over the CWA from the southwest. On Tuesday, winds begin veering towards the south which will begin advecting warmer air through the Lower Ohio Valley. Broken cloud cover will remain over much of the northern areas of the CWA, but in southern Kentucky, where more sunshine is expected, temperatures could reach into the low 70s. Expected a strong temperature gradient across the CWA as the northern Bluegrass region may only see the upper 40s for highs. Tuesday night, low temperatures will likely only drop 10 degrees or less from daytime highs due to ongoing warm air advection and cloud cover. Wednesday - Friday Wednesday, winds out of the south lift temperatures to the upper 70s to low 80s across the CWA under scattered cloud cover, but the nice warm temperatures won`t last as a strong cold front approaches southern Indiana and central Kentucky from the west. Currently, expecting the front to arrive along the western side of the CWA during the evening hours. This arrival time will help reduce the severe weather potential as the system moves eastward across the CWA. Model soundings show strong unidirectional winds from the south, but as nighttime falls, instability becomes more elevated. Low level helicity remains strong, so timing will be an important element as severe weather will be more favorable with an earlier arrival. Behind the front, cooler temperatures arrive for Friday. && .Aviation...(00Z TAF Issuance) Issued at 735 PM EDT Fri Mar 25 2022 Ceilings are hovering around 3500-4000 ft this evening, and we`ll see ceilings lift and scatter out overnight. Expect VFR conditions for the overnight, with only some very light rain chances at SDF and LEX before 06z, but no vis/cig restrictions are expected. Westerly surface winds remain gusty overnight, with wind gust speeds upwards of 25kts possible. By tomorrow morning, another VFR stratus deck will move across SDF/LEX which may result in a few more very light VCSH, but not confident enough to put in TAFs at this time. Expect slightly stronger WNW wind gusts tomorrow afternoon, possibly closer to 30kts at times. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...CJP Short Term...BJS Long Term...KDW Aviation...CJP
Area Forecast Discussion
National Weather Service San Francisco Bay Area
515 PM PDT Fri Mar 25 2022 .SYNOPSIS...Dry weather today through Sunday. A storm system will impact the region Sunday night into Monday with widespread rainfall and gusty winds. Dry and seasonable weather returns Tuesday through Friday of next week. && .DISCUSSION...as of 2:03 PM PDT Friday...Stubborn marine layer has kept temperatures fairly cool around the Bay Area today with readings in the upper 50s and 60s. Inland locations and hills have warmed into the 70s with some lower 80s far interior Central Coast. Onshore gradients remain in place and with the shallow inversion layer would expect low clouds to spread into the valleys once again tonight. Nice weekend in store for the Bay Area with plenty of sunshine and seasonably mild temperatures for Saturday afternoon outdoor activities. The incoming upper low will first makes its presence known on Sunday with a noted cooling trend as onshore winds increase along with increasing cloud cover. Inland areas will notice the cooling trend with highs in the 60s to lower 70s regionwide. Long talked about rain should arrive sometime late Sunday evening or around midnight. In a normal winter this type of storm would hardly be noteworthy but after a very dry start to 2022 it has the potential to be the wettest system since the start of the year. It appears a well organized band of rain will initially pass over the region on Sunday night, exiting the region around the time of the Monday morning commute. Enough rain expected to bring wet roads and impact the commute. However this initial rain band will be fairly fast moving and should mitigate even nuisance flooding. All attention then on the exact track of the upper low. The last two NAM runs keep it farther south heading towards San Luis Obispo. This scenario keeps the best instability and moisture farther south. The global models have a slightly farther north trajectory. Either way the best instability will be focused from around the Santa Cruz mountains southward. So unlike most storms the heaviest rain will not be in the North Bay this time but rather the Santa Cruz mountains and more likely the Santa Lucia range where 1-2 inches of rainfall will be possible. Totals of 0.25-0.50 for the valleys are currently forecast. During peak heating on Monday, in association with the cold unstable low will have to monitor for t-storms which we currently have forecast. Biggest threat would likely be small hail which can quickly become problematic on area roadways. Drying trend Tuesday through Friday of next week and likely into next weekend. Some hints in the long range for another trough and possible rain chances by April 4th or so. && .AVIATION...as of 5:15 PM PDT Friday...For the 00Z TAFs. VFR conditions prevail region-wide this evening as low clouds have completely dissipated. In addition, breezy onshore winds prevail before will gradually diminish late in the evening. Given the dissipation of stratus, even along the coast, do expect a much later return of stratus tonight into early Saturday morning. Additionally, low ceilings/visibilities will be less widespread during the TAF period with the greatest probability of MVFR/IFR/LIFR conditions mainly around the San Francisco Bay Area and Monterey Bay terminals. Expecting conditions to improve around or after 18Z Saturday over areas that do experience low ceilings/visibilities. Meanwhile, look for an increase in high level clouds as a weather system begins to approach from the west- northwest. Vicinity of KSFO...Breezy W/NW winds will persist through the evening before diminishing slightly overnight. VFR conditions are also likely to prevail through the evening with increased probabilities of MVFR/IFR conditions developing between 09Z-12Z Saturday. Conditions improve by late morning or early afternoon on Saturday along with an increase in W/NW winds. KSFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR conditions to prevail through the evening as low clouds have dissipated, even off of the coast. Additionally, moderate onshore winds will prevail before diminishing late in the evening. Do expect stratus to redevelop late tonight and into early Saturday morning resulting in MVFR/IFR and potentially LIFR conditions. Following closer to the HRRR and HREF guidance showing the latter return, generally around 09Z given current conditions. Onshore winds increase and stratus dissipates around or after 18Z Saturday. && .MARINE...as of 05:15 PM PDT Friday...Breezy northwest winds persisting through the evening but start to diminish overnight. Winds will stay strongest near coastal jet locations and through coastal gaps overnight. A prevailing light to moderate mid-period westerly to northwesterly swell will continue through the weekend. The next chance for rain will be on Sunday as a low pressure system moves toward the eastern Pacific. The system will bring southerly winds over the waters with strong gusts as well as the potential for gale force gusts near the immediate coastline. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm until 3 AM SCA...Pt Reyes to Pigeon Pt 0-10 nm until 3 AM SCA...Pigeon Pt to Pt Pinos 0-10 nm until 3 AM SCA...Mry Bay until 9 PM SCA...Pt Arena to Pigeon Pt 10-60 nm until 9 PM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 9 PM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm && $$ PUBLIC FORECAST: RWW AVIATION: RGass MARINE: McCorkle Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea
Area Forecast Discussion
National Weather Service New York NY
1006 PM EDT Fri Mar 25 2022 .SYNOPSIS... A series of cold fronts will pass through the area Saturday into Saturday night, followed by a polar cold frontal passage on Sunday. High pressure slowly builds in from the west early next week. The high weakens Wednesday as a warm front approaches from the southwest. The associated low will affect the region into Friday with a cold front passage. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... Any shower activity overnight is forecast to remain north and west of the area with a dissipating cold front. Aloft, an upper low over the Midwest drops into the Ohio Valley by morning. Ahead of it, weak upper level ridging may for a time cause clouds to dissipate before the next round approaches toward daybreak. The area will remain in a westerly flow due to a broad area of low pressure across eastern Canada. WSW winds will generally remain at or less than 10 mph. The combination of lingering clouds and winds staying up in the boundary layer tonight will lead to less of a spatial range in low temperatures. Used a combination of NBM and MET guidance, ranging from the mid 30s for parts of the Lower Hudson Valley and interior Northeast NJ to the mid 40s within NYC. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... A longwave trough remains over the Northeast for the first half of the weekend. One positive vorticity max along an upper level low moves into the area Saturday and then east of the area Saturday night. At the surface, another cold front moves across the area Saturday and then east of the area Saturday night. Another cold front will be approaching from the north and west by early Sunday. With cyclonic flow aloft, expect mostly cloudy conditions much of the time period. Rain showers will be scattered to numerous at times Saturday, highest chances late morning into early evening hours. There will be some weak instability during the afternoon into early evening hours of Saturday as well so isolated embedded thunderstorms are also forecast. Model BUFKIT soundings also convey steepening low to mid level lapse rates. With moisture and narrow CAPE in the -10 to -20 degree C layer of model soundings, there will be potential for small hail and also gusty winds. Gusts up to near 40 mph will be possible with some thunderstorms. HRRR model indicates this potential also. Precipitation tapers off by late Saturday evening into overnight. With cold air advection, rain showers could mix with snow for interior parts of the region during this timeframe before all precipitation ends. Highs Saturday were taken from NBM and subtracted one degree, ranging from the upper 40s to lower 50s for much of the region. Lows Saturday night were a combination of NBM as well as consensus of MOS and raw model data with some more weight towards consensus of raw model data. The lows range from lower 30s for interior areas of northeast NJ, Lower Hudson Valley and Southwest CT to mid to upper 30s elsewhere. && .LONG TERM /SUNDAY THROUGH FRIDAY/... A longwave trough remains across the eastern United States Sunday and slowly moves to the northeast through the midweek period as a highly amplified ridge builds slowly to the east. An embedded shortwave moves into the longwave trough for Sunday as a polar surface cold front crosses the region behind low pressure remaining across eastern Canada and the Maritimes. Guidance continues to show a highly anomalous cold airmass moving into the region behind the front Sunday night. With the shortwave Sunday, and a cold pool moving through the northeast, increasing low level lapse rates, have continued with the chance and slight chance probabilities for snow showers and/or rain showers across the region. Where probabilities are below 15% have a mention of flurries and/or sprinkles. The vort max and tough axis pass to the east early Sunday evening and end the chances for precipitation. The Arctic airmass moves into the region Sunday night and a reinforcing cold pool moves into the area for Monday. Temperatures at 850mb fall to -15C to -18C during Monday. Guidance has trended colder for Sunday night through Monday night, and the NBM has also trended colder, with the NBM 10% just a couple to 3 degrees below mean. With the MET and MAV guidance trending colder have leaned toward the NBM 10% and MET for temperatures Sunday night through Monday night. Temperatures Sunday night will be nearing record lows across a few locations, however, not expecting any at this time. With the peak of the airmass Monday and Monday night record low highs and record low minimums are possible. See the climate section for record temperatures. The airmass quickly moves east Tuesday with a warming trend setting up that remains through the week. The upper ridge moves slowly east through the end of the week with a warm front approaching Wednesday and moving north late in the day or into Wednesday evening. There is some uncertainty with the timing of the warm front as the associated surface low remains well to the west and northwest. The area becomes warm sectored for Thursday before the cold front with the low approaches and moves through Friday. For Wednesday through Friday have used the NBM temperatures and probabilities. At this time instability and CAPE are limited with the cold front so have not included thunder. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... A series of cold fronts will pass through the area Saturday into Saturday night, Mainly a VFR forecast with a chance of MVFR with showers late Saturday morning through the afternoon with an approaching cold front. Best time looks to be 18-22Z. Spotty showers may linger into the early evening. There is a chance for isolated thunderstorms beyond 18Z but not confident enough in occurrence to include in the TAFs at this time. Any TS could produce local and brief 40kt wind gusts and small hail. W/SW winds 10 kt or less overnight, increasing to 10 to 15 kt by late morning/early afternoon with gusts around 20 kt. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Amendments not expected overnight, but possible with the timing of rain showers and MVFR ceilings on Saturday. Isolated thunderstorm possible in the afternoon. .OUTLOOK FOR 00Z SUNDAY THROUGH WEDNESDAY... .Saturday Night...Mainly VFR. W/SW around 10kt G15-20kt in the evening. .Sunday through Tuesday...VFR. W/NW winds G20-25kt. .Wednesday...Mainly VFR. MVFR conditions possible in showers. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... Minor adjustments were made to the winds and gusts for current conditions. Seas were unchanged. SCA remains up on the ocean overnight mainly due to elevated ocean seas with WSW gusts around 20kt. SCA will then remain up for Saturday for the ocean east of Fire Island Inlet with seas remaining elevated. Strengthening west winds Saturday night will bring conditions back to all ocean waters. Non-ocean zones also on Saturday night could occasionally get 25 kt gusts especially late at night into early Sunday. Small craft advisory conditions will be likely on the ocean waters Sunday with a strong and gusty northwesterly flow between low pressure across the Canadian Maritimes and high pressure to the west of the waters. Gusts to SCA levels will be developing on the non ocean waters Sunday afternoon. Small craft conditions will likely continue on the forecast waters into late Monday night and then slowly diminish from west to east through Tuesday as the low moves slowly east and high pressure builds toward the waters. Sub SCA conditions are then expected on all the waters Tuesday night into Wednesday as weak high pressure remains in the area. && .HYDROLOGY... Any rain showers will be quick moving into tonight as well as Saturday into Saturday night. No hydrologic impacts are expected through the middle of next week. && .CLIMATE... Record low minimum temperatures for Monday, March 28 NYC 13 1923 JFK 22 1982 LGA 23 1982 EWR 19 1982 ISP 18 1990 BDR 17 1966 Record low high temperatures for Monday, March 28 NYC 34 1893 JFK 37 1959 LGA 36 1966 EWR 35 1937 ISP 35 1966 BDR 35 1966 Record low minimum temperatures for Tuesday, March 29 NYC 10 1923 JFK 26 1959 LGA 25 1959 EWR 23 1959 ISP 22 1982 BDR 19 1966 && .OKX WATCHES/WARNINGS/ADVISORIES... CT...None. NY...None. NJ...None. MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ355. Small Craft Advisory until 6 AM EDT Sunday for ANZ350-353. && $$ UPDATE...DW