Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/07/20

Area Forecast Discussion
National Weather Service Dodge City KS
1055 PM CDT Mon Apr 6 2020 ...Updated Aviation... .SHORT TERM...(This evening through Tuesday) Issued at 347 PM CDT Mon Apr 6 2020 Already 80 degrees this afternoon at 2 pm. A broad westerly flow aloft with a dryline positioned roughly from around Wakeeney to west of Liberal. Short term model have been all over with mix out solutions and how far the eastern extend of the drier dew points will mix out. With only a few more hours, would expect some of the less aggressive models to be correct here this afternoon with a much more moist airmass over the south central Kansas counties. We should d see quite mild temperatures once again especially over the southeast sections of the forecast area. HRRR and RAP13 are show in g a narrow are of the far southeast also with potential for dense fog development late overnight, not well supported by the HiRES models however. .LONG TERM...(Tuesday night through Monday) Issued at 347 PM CDT Mon Apr 6 2020 A fairly dry pattern extends through most of the week...probably through at least Thursday - however with a swing to much cooler temperatures likely for Thursday afternoon. We start early Tuesday with a moisture gradient across the area, with 20`s dew points as westerly winds west of the dryline and moist 50s to around d60 degree dew points in central Kansas. The drier air will continue to work eastward on Tuesday and light northerly winds develop across the entire forecast area. A prefrontal trough on Wednesday will bring an uptick in wind speeds due to the temperature gradient, however the drop in temperatures in the late afternoon and evening and strongest cold air advection though the overnight. A cool and cloudy airmass should relegate highs on Thursday to the 50s - although there is a wide range of forecast maximum temperature solutions from various models. With it no being early April, cloud cover will likely have a large impact on how warm temperatures get. A much stronger cold front is shown by the ECMWF for late Friday night and a very cold air invasion on Saturday with around freezing 850 mb level air into the southern High Plains. ECMWF also shows a cold rain/snow or just snow scenario developing over the High Plains region by the Monday and Monday night timeframe. && .AVIATION...(For the 06Z TAFS through 06Z Tuesday night) Issued at 1055 PM CDT Mon Apr 6 2020 Excellent flying weather expected through this TAF cycle. Broken cirrus currently will give way to VFR/SKC daylight Tuesday. Light SW winds currently will trend NWly through sunrise/12z Tue. A weak cold front will bring a north wind of 12-14 kts after 15z Tue, but NEly winds will rapidly diminish Tuesday afternoon/evening. && .PRELIMINARY POINT TEMPS/POPS... DDC 49 81 48 77 / 0 0 0 0 GCK 44 80 45 75 / 0 0 0 0 EHA 47 82 48 77 / 0 0 0 0 LBL 46 82 45 78 / 0 0 0 0 HYS 48 81 48 75 / 0 0 0 0 P28 55 84 52 80 / 0 0 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Russell LONG TERM...Russell AVIATION...Turner
Area Forecast Discussion
National Weather Service Grand Forks ND
940 PM CDT Mon Apr 6 2020 .UPDATE... Issued at 937 PM CDT Mon Apr 6 2020 Two t-storms moving due east across NE SD, staying just south of the border. SPC meso analysis shows best 850 mb warm advection likely occurring now in the Aberdeen to Fargo area. Waiting to see any further development into SE ND next 1-3 hours. Hard to tell. Nrn edge of 50 kt effective bulk shear and 500 j/kg cape just goes into far SE ND. So focus is far SE ND into WC MN and I think less so farther north where some short term models had some development. Removed any precip mention from DVL area as confident nothingn will happen. Low level clearing of the stratocu spread north to Cooperstown and with that fog formed locally dense esp around Valley City to Cooperstown. Did update to add more fog there this evening. UPDATE Issued at 700 PM CDT Mon Apr 6 2020 23z Sfc map shows low pressure northwest of Pierre SD with a warm front east. 850 mb warm front though is farther north into southern ND and SPC meso analysis shows 30 kts of 850 mb wind from the southwest bringing a large area of warm advection to central into southeastern ND and west central MN. Mixed layer CAPE in the 500 to 1000 j/kg range thru most of SD and into far south central ND east into the Lisbon/Forman area. Overall expecting the CAPE to increase a bit eastward as warm advection spreads east. Sufficient lapse rates above the 850 mb that elevated convection should develop and maintain itself once formed. Though degree of instability and 850 mb wind and mid level winds are not overly impressive. Therefore idea of a few strong storms developing near the SD/ND border this evening and spreading east-northeast seems reasonable. HRRR indicates a few storms also developing btwn GFK/FAR by 05z. Warm advection zone quickly shifts east into eastern MN by late tonight. So period of t-storm potential is rather small, mostly in a 6 hour period 03z-09z from west to east across the forecast area. Devils Lake area looks like the least likely to see precipitation with highest chances Bemidji to Fargo and south. && .SHORT TERM...(This evening through Tuesday night) Issued at 352 PM CDT Mon Apr 6 2020 Currently, low pressure is centered over western SD and high pressure over the Great Lakes. The low is expected to move ESE towards northern WI/Lake Superior through tomorrow morning...with warm air pushing northward ahead of it. Low level stratus is expected to continue to thicken through the evening hours and most unstable CAPE will increase in the south as well. MUCAPEs of 500-1000 J/kg may be enough to produce some large hail (up to 1" or so in diameter) from around Fargo to Park Rapids and south. The SPC has this area in a marginal risk for severe weather for tonight due to this threat. The threat for severe storms will be mainly from 9 PM to 5 AM tonight. Also, some fog may develop this evening and linger into the early morning hours. Travel impacts due to fog are expected to be limited as only patchy fog is expected. Otherwise, clouds diminish tomorrow morning...making for a mostly sunny and rather warm day with highs in the mid 40s to mid 50s. .LONG TERM...(Wednesday through Monday) Issued at 352 PM CDT Mon Apr 6 2020 A cold front will move through the area Tuesday night, ushering in cooler temps for the rest of the week. A reinforcing shot of cool air will arrive on Friday night, keeping temps on the cool side...with highs in the mid 30s to mid 40s and lows in the 20s generally. Impacts during this period are expected to be minimal as precipitation will be mainly some brief light snow or rain showers off and on through the latter part of the week and into the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 700 PM CDT Mon Apr 6 2020 Various short range models overly pessimistic with ceilings with widespread IFR ceilings forecast at 00z in NE ND where cigs are MVFR. Therefore went toward more of a MVFR cig tonight for most areas vs the forecast widespread IFR. Exception is Bemidji area where IFR cigs are more likely due to better low level moisture advection overnight. Skies will clear out late tonight into Tues AM from the west as Tuesday winds are westerly 8 to 15 kts. && .HYDROLOGY... Issued at 1259 PM CDT Mon Apr 6 2020 Flooding from snowmelt continues along the Red River and its tributaries in both North Dakota and Minnesota. Major flooding is expected along the Red River at Grand Forks and Oslo as well as along the Sheyenne River at West Fargo and Harwood. Flood crests are not yet forecast along the Red River at Drayton and Pembina with a potential crest around major flood stage in mid to late April possible. Minor to moderate flooding is forecast at many sites along the Red River, Sheyenne River, and Minnesota tributaries. Ice is still present within many tributaries and mainstem the Red River in the central and northern Red River basin, possibly leading to fluctuations in river levels away from forecast trends. Backwater will also be an issue for tributaries near the mainstem Red River. Temperatures above freezing throughout the day and night are expected to melt most of the remaining snowpack today through Wednesday, with a cooler trend later this week bringing temperatures back below freezing at night. This melt will cause secondary crests for many locations that have already seen initial snowmelt crests, as well as prolong crests for multiple days particularly for the Red River at Grand Forks and Olso. Forecast precipitation through Tuesday 7 AM have been included in current river forecasts. While isolated high QPF amounts will be possible between half an inch to one and a half inch from showers and thunderstorms today through Tuesday, the very small footprint of this high QPF shouldn`t have a substantial impact on riverine flooding. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. River point flood warnings continue across portions of the region. Refer to the latest flood warnings and statements for detailed information on specific locations. && $$ UPDATE...Riddle SHORT TERM...Knutsvig LONG TERM...Knutsvig AVIATION...Riddle HYDROLOGY...CJ
Area Forecast Discussion
National Weather Service Louisville KY
949 PM EDT Mon Apr 6 2020 .Forecast Update... Issued at 949 PM EDT Mon Apr 6 2020 It still looks like a quiet night tonight with dry conditions and temperatures retreating into the 50s. Storms will develop on the nose of a low level jet over northern parts of Illinois and Indiana but 850-300mb flow will take that activity east-southeast and keep it north of the middle Ohio Valley. There may be a brief window of opportunity for some valley fog in the Lake Cumberland region near dawn. The atmosphere will become unstable tomorrow but we`ll have to wait until tomorrow night for a good trigger as a cold front enters the region from the northwest. Only moderate shear, weak low level lapse rates, and not much moisture to work with, but plenty of instability and steep mid level lapse rates with WBZ heights around 9k` for a hail threat. Best timing appears to be between midnight and dawn early Wednesday, from north to south. && .Short Term...(Tonight through Tuesday evening) Issued at 304 PM EDT Mon Apr 6 2020 A warm front is lifting north across the region at this hour, and should continue to do so in a dry fashion as there isn`t much of a trigger to work with. Temps should peak in the mid to upper 70s in most spots, minus the NE where some thicker clouds have been noted through the day and the warm front will take the longest to pass. Can`t rule out a stray shower/storm this evening across our southern border as some activity could fire along the Cumberland Plateau and move into our region. Soundings do show it uncapped during that time with some modest instability, but without a real trigger think coverage would be isolated or not at all. The HRRR has been consistent in firing off some activity there around sunset, so included a slight chance mention. Otherwise, expect a mostly quiet/dry overnight with perhaps a warm advection showers/sprinkles hanging around. In may stay clear/calm enough for more patchy valley fog once again. Will also note a complex of storms over the southern Great Lakes region, staying off to our north and east through the overnight. The daylight hours of Tuesday are expected to be dry and a bit warmer under steady (and maybe even a bit gusty in the 20-30 mph range at times) winds. Most values are expected to top out in the 75 to 80 degree range. ...Strong Storms Possible Later Tuesday Night... A surface low will push across the Great Lakes Tuesday night, with a trailing cold front sagging southward toward the Ohio River Valley later Tuesday night. Ahead of this feature, scattered showers and storms are expected to develop in the warm sector along a pre- frontal trough/wind shift then drop into southern IN and central KY through the overnight. Given moderate instability (1500-2000 J/KG of SB CAPE w/ steep mid level lapse rates), and good deep layer speed shear, organized storm modes are possible including bowing segments and perhaps some supercells. The main threats would be large hail and damaging winds in addition to brief heavy rain and lightning. However, we will likely carry a small tornado threat as well as any stronger rotating storm as a secondary threat. Right now, 0-1 km effective SRH values look to be more in the 100-200 m2/s2 range which is why the tornado threat is a little lower, but not zero. Will have to watch for any localized effects/boundaries that may enhance that threat a bit in certain areas. Prime time looks to be roughly from 03-12z into Wednesday morning. && .Long Term...(Tuesday night through Monday) Issued at 237 PM EDT Mon Apr 6 2020 Wednesday will see a weak cold front pass southeast through the Ohio Valley. This will act as a squeegee pushing remaining low precip chances into eastern Kentucky by the afternoon. Behind this, a relatively small area of surface high pressure, to our southwest, will help to clear skies raising high temperatures into the mid 70s to around 80. Wednesday night will see a more meaningful cold front move through the area. Behind this front lies a tight gradient upper trough digging to the south. At the surface, high pressure, centered over western Canada, with tight pressure gradients extends to the rear of the front. Tight surface gradients will push winds to around 10-15 mph with gusts to around 25 mph. This will drive temperatures down as cold air advects into the area. Even with mostly clear skies on Thursday, after the rain, highs will only reach into the mid 50s with the warmest areas near the Tennessee border hitting 60. At this time, no real changes take place until Friday night into early Saturday. This is when surface high pressure to the south passes east of central Kentucky. This will bring southern flow back to the region and lift highs on Saturday, Sunday, and Monday back into the 60s. This time period will also likely see a mild cold front stretching from the southwest to the northeast move southeast through the Ohio Valley. This would bring low rain chances to the region, but for now, the models don`t have a handle on timing. Keeping low chances through this period for relatively light rainfall. && .Aviation...(00Z TAF Issuance) Issued at 700 PM EDT Mon Apr 6 2020 VFR conditions are expected through most of the forecast period. Winds will veer from the south towards the southwest as the region gets gusty during the day tomorrow. At the end of the period, rain chances in southern Indiana will begin moving south towards central Kentucky. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...13 Short Term...BJS Long Term...KDW Aviation...KDW
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
839 PM CDT Mon Apr 6 2020 .UPDATE... 830 PM CDT The radar scopes are still pretty quiet early this evening, but anticipate that changing over the next few hours as a low-level jet and modest shortwave disturbance begin to interact with an impressively steep lapse rate plume overhead. Recent GOES-16 atmospheric motion vectors and radar VWPs hint at the presence of a shortwave drifting east across central Iowa at this hour, and can also see indications of this in Simple Water Vapor RGB loops. Ahead of this feature, a modest low-level wind max is starting to migrate northward closer to a warm frontal boundary which is starting to inch into our region. Atop this boundary, mid-level westerlies have advected an impressively steep EML plume into the area, with a core of 8.5-9 C/km 700-500 mb lapse rates noted in recent SPC mesoanalysis across Iowa. The evening DVN RAOB sampled the eastern periphery of this EML, depicting 8.9 C/km lapse rates from about 690-550 mb. In addition, this RAOB shows perhaps a bit more moisture presence up to 700 mb than recent forecast models would indicate, although there still is some work to be done to erode lingering elevated capping (MUCINh of -50 J/kg). As the aforementioned shortwave and LLJ ramp up, should see the lingering warm/dry portion of the airmass in the 750-650 mb layer continue to cool and moisten as it`s lifted, eventually supporting the development of elevated convection through the late-evening and overnight hours. Still some question as to just how robust/expansive convective development will be given the presence of mid-level pockets of dry air and a lingering warm nose ("CAPE robber") around 600 mb. While 0-6 km deep layer shear is rather robust (around 40 kts), thinking is that effective deep layer shear may be a bit more subdued (closer to 30-35 kt) with slightly elevated effective inflow layers. As a result, the current "Marginal" risk for a few quarter-size hailers seems reasonable (perhaps with a gusty wind threat, although low-level static stability may ultimately curtail this threat). Finally, we`re still watching the conditional severe potential for tomorrow (Tuesday) afternoon and evening. Main questions continue to revolve around the strength of the cap. 00z RAOB out of Denver showed +20 to +23 C temperatures in the lowest 50 mb which, with some modification, will become the base of our EML plume tomorrow, potentially planting a cap of forged steel overhead. That said, ECMWF has been consistently eroding this through the afternoon, and extended RAP and 18z GFS show us getting to within a stone`s throw of lifting/eroding this feature during the late-afternoon-- volleying updrafts into an environment supportive of organized severe modes. We`ll continue to analyze the latest observational trends and guidance with the overnight package. Evening updated products will be out shortly. Carlaw && .SHORT TERM... 303 PM CDT Through Tuesday night... Main forecast concerns are timing/coverage of thunderstorm potential over the next 24 hours or so. Breezy southwest winds Tuesday will support temps well into the 70s for the area. Surface warm front extends from low pressure over western South Dakota, southeast across Iowa and into central IL/southern IN as of 2 pm. Front has made decent progress over the past few hours, surging north and just crossing the ILX/LOT border area per latest analyses. Elevated mixed layer (EML) has spread in aloft overnight, noted in upstream soundings including ILX and DVN this morning above about 750 mb. While effectively capping convective development for surface or near-surface based parcels, this has resulted in a region of steep lapse rates (7-8 C/km) aloft. Thus the precip/convection threat is expected to be primarily north of the warm front late this afternoon, in association with a couple of low-amplitude mid-level short waves tracking through the region. The first of these was tracking WI/northern IL at this time, producing an area of elevated showers mainly north of the I-88 corridor. There had been some lightning with these just south of Rockford earlier, through RAP mesoanalysis data indicates weak MUCAPE axis was largely off to the west of the current shower activity. Thus while isolated/embedded thunder is possible over the next 1-2 hours, it should be limited. Deepening low level moisture later this evening should have a better potential to tap into the steep lapse rates aloft, coincident with an increase in low level jet flow to 35-40 kt. While isolated to scattered showers and a few thunderstorms are possible through the evening, CAM guidance continues to indicate an uptick in deeper convection toward/after midnight. MUCAPE around 1000 J/kg and effective bulk shear 25-30 kt may support updrafts capable of producing isolated hail, with freezing levels around 8500 ft. A few cells could be rooted within/close to the boundary layer such that they could pose an isolated wind gust threat as well. Eastward storm motions around 30 kt should preclude significant heavy rainfall threat, unless localized training occurs. Surface low lifts northeast across the upper Mississippi Valley Tuesday morning, in association with a deeper short wave and upper jet max tracking across the northern tier of states. Warm front lifts north of the forecast area in response, with a breezy warm and humid day in store for the forecast area in the warm sector of the system. Forecast soundings continue to show a strong capping inversion for much of the day beneath the EML, though there is some erosion of the cap noted later in the day as warming maximizes and low level moisture increases ahead of an approaching cold front. The presence of strong conditional instability (1500-2000 J/kg) and 35- 45 kts of deep layer shear would certainly support the potential for strong/severe storms should be able to break the cap and convection initiate along/ahead of the front. SPC has shifted the marginal and slight day 2 convective outlook substantially farther east than previous with the potentially late initiation. Some concern that convection could still initiate a little sooner, with main threats being wind and hail. Threat of storms/severe would linger into the evening hours across the southeastern cwa before passage of the cold front ends precip from northwest to southeast by around midnight. Breezy southwest flow in the warm sector should have no problem warming temps across the area Tuesday. Local 925 temp climatology supports mid-70s across much of the area, with even some upper 70s not out of the question if cloud cover is not too significant. Ratzer && .LONG TERM... 400 PM CDT Wednesday through Monday... Main concerns through the extended: -Showers and possible thunderstorms along cold front Wednesday -Gusty winds Thursday -Below normal temps Thu-Fri -Off and on precip chances With the passage of a weak cold front Tuesday evening, temps should rebound into the 60s and low 70s across the area Wednesday. A stronger cold front then pushes through the area Wednesday evening bringing in an area of showers and possibly some embedded thunder. Thunderstorm potential is highly dependent on how things ultimately evolve on Tuesday, but there is a window for thunderstorms Wednesday evening, especially for areas south of I-80. The better chances for strong to severe storms currently remains to the south of our area. A cold air advective regime sets up behind the Wednesday system resulting in breezy and cooler conditions across the area Thursday and Friday with highs 5-10 degrees below normal in the upper 40s and low 50s. The GFS has trended a bit higher with wind gusts with the latest run closer to the ECMWF, so decided to bump up wind speeds/gusts Thursday with gusts to 35-40mph possible. Beyond Friday, plenty of uncertainty exists as another system approaches over the weekend with highs near normal in the 50s. Petr && .AVIATION... For the 00Z TAFs... A active period of weather is expected over the next 24 hours as a low pressure system approaches from the northwest. Weather: A warm front south of the terminals will be the impetus for precip through the night. Isolated to scattered showers are expected this evening before a low-level jet veering into northern Illinois amplifies shower coverage/intensity around or after midnight, with embedded thunder expected during this time. The activity should shift southeast late tonight as the LLJ continues to veer more westerly. Other than a small chance for some DZ late tonight into mid-morning Tuesday, conditions will then be dry well into Tuesday afternoon. A cold front will quickly track SE across northern IL late afternoon into early evening. While strong to severe storms are possible along the front, a rather capped pre-frontal environment will likely significantly limit thunderstorm development. Wind: A generally light SE wind is expected north of the warm front into the overnight hours before veering light S or SW toward daybreak as the warm front begins to lift north. Expect winds to shift SW with gusts of 20-25 knots behind the warm front. NW winds with gusts of around 20 knots will follow the cold front Tuesday evening. Ceiling/Visibility: Ceilings will lower through this evening, settling into IFR to potentially LIFR levels north of the warm front late this evening into Tuesday morning. Ceilings should rapidly improve as the front passes in the morning, with an improvement from IFR to VFR possible in just an hour. BR will likely be prevalent north of the warm front after precip chances diminish late tonight, with some pockets of IFR visibility possible. Kluber && .LOT WATCHES/WARNINGS/ADVISORIES... IL...None. IN...None. LM...None. && $$ Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
807 PM CDT Mon Apr 6 2020 .UPDATE... Just a quick update to confirm an end to our precip chances for this evening. Aside from a couple of light showers in the Rolling Plains, storms failed to develop along the dryline. The dryline will be overtaken overnight by a Pacific-type front that will move through the area and bring a drier airmass on west winds. That will put an end to the two night stretch of low stratus and fog at Lubbock, but we could see some light fog in the Rolling Plains before the front moves through. && .PREV DISCUSSION... /issued 633 PM CDT Mon Apr 6 2020/ AVIATION... Aside from a window of possible visibility reductions due to fog at KCDS overnight, VFR conditions should prevail at all terminals. S-SW winds will shift around to West overnight, then to the NW during the day Tuesday. PREV DISCUSSION... /issued 242 PM CDT Mon Apr 6 2020/ SHORT TERM... High clouds continue to stream across the area and the low clouds and fog finally have burned off or lifted for all but the far southern Rolling Plains. Main issue for the forecast is the remainder of the afternoon to around sunset as models are struggling with how surface fields have evolved so far. 12Z runs of the high- resolution models showed a broad dryline mixing to the edge of the Caprock by this 21Z with dewpoints dropping into the low 40s west of the mixing zone. They also veered surface winds to the southwest across the South Plains but West Texas mesonet observations show that this hasn`t happened except across the northwestern South Plains and Rolling Plains. Corridor of southeasterly surface wind roughly south of State Highway 114 and west of U.S. 87 is helping to hold mid 50 dewpoints in place across the southern South Plains, and a few low 60s are now showing up in the Rolling Plains on southwesterly surface flow. Latest runs from 18Z of the HRRR and RAP have a much better handle on conditions now than on earlier runs but still look to try and mix the dryline to the east too fast compared to observations. There also continues to be a persistent signal to the southwest of Lubbock across the northwestern Permian Basin for isolated storms potentially developing later this afternoon. Model soundings all show that there will continue to be a strong cap in place between 800 to 700 hPa for locations in our forecast area but it does get pretty close to breaking across the southwestern South Plains between 5 and 6 pm. One other change from earlier runs is that a bit of elevated instability across the eastern South Plains has pretty much disappeared from model soundings. With all this taken into consideration, there is still a small but dwindling chance there could be isolated storms developing across the southern South Plains tracking into the Rolling Plains this afternoon but any storms that do develop should quickly dissipate after sunset. Will hold onto the slight chance PoPs for this afternoon but have the forecast dry after 00Z/7 pm CDT. Wind will gradually veer to the southwest to west as the surface trough moves off to the east of the region. Wind will continue to veer overnight to the west and this will mix drier air across the Caprock into the western Rolling Plains overnight. The dryline will start off the day roughly along a Childress to Post line and will continue to mix east through the morning so that dry west to northwesterly flow settles in over the forecast area. This will help boost highs into the mid 80s for the Caprock with some readings near 90 across the eastern Rolling Plains. Wind speeds should be low enough that even with relative humidities in around 10 percent in the afternoon tomorrow, fire danger should not be too high. Jordan LONG TERM... Overall quiet weather will last Tuesday through at least Wednesday evening as upper ridging remains overhead. By Thursday an upper low will be located somewhere over the southwestern US. Models overall tend to disagree with the location with the GFS having the low over the Four Corners region by Thursday afternoon and the ECMWF having it remain over southern CA/AZ through Friday evening. The resulting GFS solutions would bring the potential for showers and thunderstorms Thursday afternoon in addition to a backdoor cold front. The ECMWF keeps things mostly quiet Thursday. If the pattern does end up following more in line with the GFS thunder potential should be mostly limited as precip will be mostly isentropic. Models tend to fall more in agreement by the late weekend. The GFS develops a new upper low over northern Mexico and brings it eastward over the FA by Sunday. The ECMWF is similar except instead of developing a new low it uses the previously mentioned low over southern CA/AZ. Both models bring a cold front into the region by Sunday as the upper low opens and pushes east of the FA. The GFS is much more bullish with precip chances behind the front on Sunday. Models diverge even further going into early next week with the GFS having a more zonal flow pattern and the ECMWF bringing a second cold front into the region. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 33
Area Forecast Discussion
National Weather Service Marquette MI
624 PM EDT Mon Apr 6 2020 .SHORT TERM...(This evening through Tuesday) Issued at 358 PM EDT MON APR 6 2020 WV imagery and RAP analysis indicated a northern stream mid/upper level trough off from Alberta into Montana, a southern stream closed low near the northern CA coast and a broad ridge over the southeastern CONUS resulting in anticyclonic westerly flow through the northern Plains and northern Great lakes. At the surface, sse flow was increasing through the Upper Mississippi Valley between high pressure over the central Great Lakes and a trough the western Plains. A continued WAA pattern supported mainly mid clouds and a few sprinkles over mainly eastern Upper Michigan. Tonight into Tuesday, expect dry weather this evening as isentropic lift temporarily weakens. Although the stronger forcing with a shortwave trough lifting from southern Saskatchewan to northwest Ontario will remain to the north of Upper Michigan the approaching sfc-850 trough with strengthening WAA/290k-300k isentropic lift and moisture advection will bring showers into the west late tonight and across Upper Michigan Tue morning into the early afternoon. Models suggest that heavier band of rain with QPF to around 0.25- 0.50 inch is expected across the north, especially the Keweenaw. However, confidence in the location of the heavier rain band is still low. Even with the better elevated instability remaining south of Upper Michigan, mid level lapse rates to 7.5C/km along with the stronger band of lift could still support some isold tsra, mainly over southern Upper Michigan. Under cloudy skies, temps will still climb into the mid to upper 40s north and the low to mid 50s south. .LONG TERM...(Tuesday night through Monday) Issued at 337 PM EDT MON APR 6 2020 The past few longterm AFDs cover the largescale features fairly well, and latest ensemble forecasts suggest these features haven`t changed much. A ridge over the Pacific shifts E and drives troughing across the West Coast before this trough shifts E into the central CONUS by mid-week. Soon after the start of the longterm period, a strengthening system will approach Upper Michigan that brings a cold front across the Upper Midwest as the above normal temps that start the week transition back to near normal. As ridging over the Pacific continues, ridging over the Atlantic develops...leaving large-scale troughing inbetween across the central CONUS. This pattern is expected to continue into next week, with the chance of trending towards below normal temperatures begins to look likely. Tuesday night into Wednesday, remaining showers from Tuesday`s shortwave will be exiting from W to E early through the night. There may be lingering -TSRA right along Lake Michigan, but have only maintained the slight chc in the forecast for the first few hours after 00Z Wed. Attention then turns to the anticipated shortwave and associated cold front progged to pass through the region starting Wednesday evening. 500mb heights in the low to mid 5400m`s before the fropa quickly fall to near 5200m behind the front. Behind this front, a rapidly developing low pressure system deepens as it passes just to the E of Lk Superior overnight Wednesday. Pres falls right near the sfc low pressure are fairly significant, but remain to the E of the region. Over the UP and Lk Superior pressure falls of 0.5 mb/hr are suggested. As sfc high pressure approaches from the W, this leaves a tightening pressure gradient over the region as winds increase through the night Wed into Thurs. By Thursday afternoon, it looks like for frequent gusts across the UP to reach 30 mph, with locations across the Keweenaw, higher terrain, and along Lake Superior (especially east) have the potential reach upwards of 40mph. In terms of precipitation, models suggest most of the precipitation is tied to the cold front and sfc trough. As the wave and assoc. sfc low begin to shift out of the region, models do suggest some wrap around precipitation in pockets of vorticity and embedded shortwaves. With 850mb temps near -10C, there is some potential for lake enhancement of any of this wrap around showers should synoptic forcing do most of the work. Heights and 850mb temps will be on the rise Friday afternoon with residual -SHRASN diminished overnight Thursday, Friday looks to be mostly dry and cloudy in the morning, with some clearing in the afternoon with rising heights. Then, models suggest another shortwave to drop south from Canada on Saturday into Sunday. Guidance today shows this wave to be more organized as widespread troughing begins to take hold across much of the central CONUS. At this time it doesn`t look like anything major, but another round of nuisance -SHRASN looks possible over the weekend as temperatures drop closer to normal. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 624 PM EDT MON APR 6 2020 VFR conditions will continue through tonight as mid-level clouds remain. Clouds will lower Tuesday morning with rain moving in ahead of low pressure approaching the region. Expect cigs to drop to IFR at all sites as the rain moves in. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 358 PM EDT MON APR 6 2020 East-northeast winds will increase to 20 knots over the west half of Lake Superior into tonight as trough approaches from the west. East to southeast wind gusts could increase up to 25kt over the east and north central parts of the lake on Tue as the gradient tightens ahead of the trough. The next big increase in winds will occur late Wed into Thu as low pressure system deepens north and east of the lake and an associated cold front moves through the area. West winds increase to 20-30 knots late Wed into Wed evening and then become northwest gales of 35-40 knots late Wed night into Thu, strongest over the east half of the lake. Northwest winds will quickly diminish blo gales Thu night and to less than 20 knots on Fri as high pressure builds in from the west. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...JAW AVIATION...07 MARINE...JLB
Area Forecast Discussion
National Weather Service Shreveport LA
951 PM CDT Mon Apr 6 2020 .UPDATE... Interesting update overnight as we dealing with mostly mid and high level moisture as it pertains to a lack of cloud cover below 10kft. We are also continuing to deal with upper level ridging, albeit weak ridging aloft, across our entire region as well. Embedded in this flow however are weak and subtle pockets of upward forcing that is basically oriented near and north of the I-20 Corridor. The latest 00z NAM as well as the latest HRRR is trying to focus more in the way of scattered convection overnight near and north of the I-20 Corridor of NE TX and N LA, especially north of this Corridor, encompassing our northern half. There does appear to be some theta-e ridging that just happens to coincide with this activity across our northern zones. Low level winds do increase overnight as well which should help isentropic process. The forecast already has a pretty good handle on this outcome. Did rearrange pops slightly but it will not constitute an update to this forecast. Temps are within 2 to 5 degrees from overnight mins in some locations but there should not be too much in the way of additional temperature falls overnight. 13 && .PREV DISCUSSION... /issued 649 PM CDT Mon Apr 6 2020/ AVIATION... VFR ceilings currently prevailing across our entire airspace late this evening but MVFR ceilings lay in wait across SE TX into SW LA attm. As we go through the overnight hours, expect these ceilings to build northward, encompassing first our NE TX terminals, then the SHV and TXK terminals and eventually the ELD/MLU terminals. Could also see some scattered convection near but especially after midnight near the I-20 Corridor terminals and our airspace north of the corridor as well so made this mention in the 00z TAF package. Cannot rule out some IFR ceilings, especially at the LFK terminal in association with the returning stratus towards sunrise or at the ELD terminal with expected precipitation but for now, have left this possibility only at these terminal locations for late tonight through mid morning. It appears any convection should move north and east of our airspace by late afternoon on Tue so have trended ceilings back to low VFR variety across most locations as well by this time. Look for southeast to south winds generally below 10kts overnight with S winds becoming SSW at most locations on Tue with speeds near 8-12kts, with some gusts possible across our NE TX terminal locations. 13 && .PRELIMINARY POINT TEMPS/POPS... SHV 66 84 69 89 / 30 30 10 10 MLU 67 82 70 89 / 30 60 10 20 DEQ 63 81 63 87 / 40 20 10 10 TXK 65 81 67 86 / 40 30 10 10 ELD 65 82 68 88 / 40 50 10 10 TYR 66 84 69 88 / 30 20 0 10 GGG 65 84 68 89 / 30 20 0 10 LFK 68 85 68 90 / 30 20 0 10 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ 13/13