Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/26/18

Area Forecast Discussion
National Weather Service Cheyenne WY
744 PM MDT Sun Mar 25 2018 .UPDATE... Issued at 739 PM MDT Sun Mar 25 2018 Decided on a Winter Weather Advisory for the I-80 Summit this evening. WYDOT observations showing visibilities anywhere from 1/4 to 1/2 mile in moderate to heavy snow. Radar has a band of moderate reflectivity right over the Summit and IR imagery showing cooling cloud tops southwest in northern Colorado. Believe it will be short lived as better lift moves north, but did not want to chance it as there is a lot of traffic seen on webcams. Updates have been sent. && .SHORT TERM...(This evening through Monday) Issued at 257 PM MDT Sun Mar 25 2018 Was tempted to take thunder out of the forecast on the afternoon package, however LAPS data still showing a solid 200-400 j/kg of CAPE across our central zones and higher res satellite imagery confirms that we do have some taller buildups in that area and IR imagery shows cooling cloud tops ahead of the initial shortwave moving through the central Rockies. As the initial shortwave drives east this evening, we will get a push of colder air late tonight with 700 MB temps falling to around -8C where we have the Winter Weather Advisory posted. Latest model ensembles still advertise the heaviest snowfall tonight into Monday to occur just to the north of our area, but there is still a chance that we could see localized 4 to 7 inches on ridges and mountains across northern Carbon and Albany counties as well as closer to the heavier band of snow that will cross extreme northwestern Converse county. So, with that we will keep the Winter Weather Advisory posted where the midnight shift had it for. .LONG TERM...(Monday night through Sunday) Issued at 257 PM MDT Sun Mar 25 2018 Precipitation will gradually taper off Monday with the next chance of precipitation still expected to move in from the north on Wednesday along a cold front. No changes from the midnight shift. /JG Long range models in agreement with the overall pattern, which suggests a prolonged period of unsettled weather across southeast Wyoming and western Nebraska through the week. Models and ensembles are struggling with the timing of the shortwave activity expected to push across the area for mid to late week, which is to be expected several days out. All models show progressive northwest flow on Wednesday as the first wave moves across Wyoming. Decent dynamic forcing, llvl, and unstable conditions may lead to rain/snow showers changing to all snow through the afternoon and evening hours on Wednesday. Exact timing is tough to pin down at this time, but evening rush hour impacts are possible. Soundings show pretty unstable conditions along the cold front as it stalls across the mountains, so will need to monitor the potential for heavy snow showers or snow squalls through Wednesday evening. Increased POP between 50 to 70 percent, especially along the I-80 corridor and in the mountains. High temperatures will be tricky to forecast on Wednesday, due to the timing of the cold front in addition to wet-bulb cooling once any precipitation develops. Highs in the 40`s are possible before temperatures rapidly fall into the 30`s and even upper 20`s late in the afternoon. Models indicate the first shortwave progressing southward early Thursday morning, with a few more disturbances embedded in the northwest flow aloft rapidly moving southeast across the region. Can not rule out a continuation of snow and rain showers through early Friday morning. For the weekend, the GFS and Canadian show a cold and snowy pattern for the area as an arctic cold front stalls across the mountains, and the main upper level trough digs further to the west as it slowly translates southward. The ECMWF is more zonal with the upper level pattern and doesn`t show nearly as much activity, while the ensemble forecasts lean towards the GFS and Canadian. Increased POP slightly next weekend, but kept temperatures in the 40`s to mid 50`s during the day. /TJT && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 511 PM MDT Sun Mar 25 2018 Widespread IFR event taking shape east of the Laramie Range out into the Nebraska Panhandle this evening as a low pressure center brings widespread moisture to the area. Easterly upsloping winds are expected to bring IFR ceilings into the Panhandle around 03Z with possibility of LIFR in fog/snow after 06Z tonight. Used latest HRRR for guidance on onset and duration of IFR/LIFR conditions. Will continue to monitor. && .FIRE WEATHER... Issued at 257 PM MDT Sun Mar 25 2018 No changes for the afternoon update. /JG No fire weather concerns over the next several days. Gusty wind is possible at times, but RH values should remain well outside of our critical thresholds. Expect scattered showers & thunderstorms this afternoon/evening, and accumulating snow over northern areas later tonight and early Monday. /CLH && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Winter Weather Advisory until noon MDT Monday for WYZ101-102-104. Winter Weather Advisory until 2 AM MDT Monday for WYZ116. NE...None. && $$ UPDATE...GCC SHORT TERM...JG LONG TERM...JG/TJT AVIATION...GCC FIRE WEATHER...JG/CLH
Area Forecast Discussion
National Weather Service Sioux Falls SD
910 PM CDT Sun Mar 25 2018 .UPDATE... Issued at 904 PM CDT Sun Mar 25 2018 Expanded the winter weather advisory for freezing rain and freezing drizzle about one row of counties westward including Minnehaha county. Temperatures in the new headlined area are running one to two degrees cooler than previous forecast, and the HRRR and RAP are keeping temperature readings very close to freezing tonight through mid morning Monday. The ice may be rather soft on road surfaces, and treated road surfaces will likely be in good shape. But elevated surfaces, sidewalks, driveways, etc., will likely get pretty slick. The worst of the icing is expected in southwest MN and Brookings county SD where temperatures will hover in the upper 20s to near 30 degrees. There may be some melting in southwest MN Monday afternoon, only to refreeze again Monday evening. && .SHORT TERM...(This evening through Monday) Issued at 330 PM CDT Sun Mar 25 2018 Complicated forecast tonight and Monday, as precipitation develops and expands across the region in response to a broad mid-upper level trough swinging out of the Rockies. Confidence in precipitation occurring is pretty high, but precipitation type is much less so. Still seeing some issues with saturation aloft leading to potential for drizzle instead of bonafide rain/snow at times. For this, leaned more heavily on GFS/NAM projections of saturation in the critical ice-bearing layer, but even with this, there are areas where ice introduction will be lacking at times over the next 24 hours. Also have a warm layer aloft which will limit snowfall south of Highway 14, but in turn will contribute to the potential for freezing rain/drizzle in areas where surface temperatures remain near freezing for several hours. This appears to be most likely in areas east of a line from Brookings-Luverne-Storm Lake, particularly in the more elevated areas of southwest MN, and feel confident enough in icing potential in these areas to issue a Winter Weather Advisory for freezing rain in these areas from late this evening through Monday. Advisory may need to be expanded by later shifts if confidence in icing farther west grows. Travel impacts of icing may be alleviated for a time during the afternoon, when road temps could rise above freezing, but this will not help impacts to trees and potentially power lines, so will run the advisory all the way through the afternoon, and into the evening when precipitation should be diminishing west to east. Enough energy/elevated instability above the deep isothermal layer across our southeast by midday/afternoon to include a mention of thunder for most of northwest Iowa, and nearby areas of extreme southeast South Dakota/northeast Nebraska. Fortunately, temperatures at the surface in these areas should be warm enough to minimize the risk of convective freezing rain. .LONG TERM...(Monday night through Sunday) Issued at 330 PM CDT Sun Mar 25 2018 The extended forecast begins with wintry precipitation continuing in our eastern zones as the main wave finally begins to push through. Exact precipitation type remains a source of contention at this time. Profiles struggle to become saturated above the -10C level, suggesting type will not include snow. Lack of a deep cold layer near the surface seems to mostly rule out sleet. Surface temperatures across northwest Iowa look to be just above freezing, so will anticipate rain there. Southwest Minnesota could have lingering freezing rain as temperatures may hang back just below freezing there. Either way, precipitation should end by 06z Tuesday. While the main wave passes Tuesday, flow aloft remains somewhat zonal in its wake, which will actually allow a slight warming trend. We`ll be under the influence of the left entrance region of a jet streak and will remain dry thanks to large scale subsidence. Thermodynamic profiles appropriately dry out pretty quickly by Tuesday afternoon, allowing our ever improving sun angle to help us heat up. Wednesday, a slight disturbance will induce southerly flow early before a cold front passes early in the afternoon. PV and isentropic fields imply there will be decent lift with this disturbance. While moisture profiles are marginal, could easily see some spotty rain, especially in our south. There does seem to be enough of a pressure gradient to drive some mixing that may be able to access warmer air aloft even after the surface front passes. Bumped up winds and high temperatures accordingly. The upper flow starts to become more amplified for Thursday/Friday with slight disagreements amongst guidance. Best chances are Friday night with temperatures cool enough to support another chance for snow across the region as April approaches. Zonal regime returns by the weekend, keeping our temperatures at or slightly below normal with stubborn lingering chances for precipitation. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 633 PM CDT Sun Mar 25 2018 IFR to LIFR conditions will be common for the area through the 00Z TAF period. The best chance for a freezing rain, or a rain and freezing rain mix, will occur at KFSD late tonight and early Monday. There could also be isolated thunderstorms at KSUX Monday afternoon but the chances of that happening at a specific point location are too remote to include at KSUX at this time. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...Winter Weather Advisory until 10 AM CDT Monday for SDZ055-056- 062. Winter Weather Advisory until 1 AM CDT Tuesday for SDZ040. MN...Winter Weather Advisory until 10 AM CDT Monday for MNZ098. Winter Weather Advisory until 1 AM CDT Tuesday for MNZ071-072- 080-081-089-090-097. IA...Winter Weather Advisory until 10 AM CDT Monday for IAZ001>003- 013-014-021-022. NE...None. && $$ UPDATE...MJ SHORT TERM...JH LONG TERM...Ferguson AVIATION...MJ
Area Forecast Discussion
National Weather Service Fort Worth TX
1002 PM CDT Sun Mar 25 2018 .UPDATE... As is usually the case nocturnally in the spring and early summer months, the surface dryline and associated surface low continue to retrograde back westward toward the better mid level height falls across eastern New Mexico and West Texas. Temperatures ranged from the 60s across the northeast counties, to the 70s elsewhere under considerable, multi-level cloudiness streaming within strong southwest flow aloft over the area. After a vigorous supercell with very large hail affected northern parts of Montague County earlier this evening, sensible weather has quieted down. The boundary layer will continue to stabilize and we will await the next of several disturbances to arrive across West-Central Texas and the South Plains early Monday morning. In addition, another surge of low stratus clouds will arrive northward and encompass most of the area except the far western counties. Combined with breezy south-southeast winds 10-15 mph, low temperatures will definitely feel spring-like with low temperatures remaining well up into the 60s with plentiful humidity around. Monday will become active by afternoon with a severe threat from I-35/35W back across our W/NW counties, as the dryline nudges eastward during prime heating. 05/ && .AVIATION... /Issued 713 PM CDT Sun Mar 25 2018/ /00Z TAFs/ Lower MVFR cigs that have persisted much of the day have finally dissipated the past hour more with multiple level, SCT-BKN VFR level clouds. Winds continued from the SE around 15 knots, as a warm front extending from a surface low near KPRS/KSPI across KSPS and across extreme southern OK near KADM and KDUA. Isolated severe storms were occurring between KSPS/K0F2. Winds should diminish closer to 10 knots overnight and convection well to the NW of the DFW terminals likely will track east across, or just north of the Red River Valley. Challenges overnight will be mainly stratus and timing restrictions of cig heights. Thermodynamically, it appears favorable areas for ISO-SCT TSRA will remain well off on the Bowie and Bonham cornerpost near the TX/OK border and well west of I-35 with the next approaching shortwave arriving from W TX Mon a.m. Can`t rule out a few rogue showers near DFW terminals, but Waco Regional should remain free of convection further south and underneath the weak shortwave upper ridge. Confidence is too low beyond 18z for any mention of TSRA/VCTS, with majority of better focus both surface and aloft just to the NW of the Metroplex and even more so for Waco. .DFW Terminals... RUC and NAM models differ slightly on return of MVFR cigs into the area, so took a mean of around 07z Sun morning above FL020, lower below FL020 by 11z, with a TEMPO potential for IFR through 15z Sun. Cigs should rise back into low VFR between FL030-040 by 21z-22z Sun afternoon. SE winds 10-15 kts through 15z Sun, become S 15-20 kts with gusts to 25 kts by 18z and after. Moisture below the inversion aloft will be relative deep and cigs slow to mix. .Waco Regional Similar trends on winds and flight restrictions as terminals across DFW, except MVFR cigs should arrive by 06z Sunday, before dropping down into IFR by 10z Sun and prevailing. Cigs should rise to MVFR later Sun morning with VFR returning mid-late afternoon hours once again, as moisture below the inversion aloft will be relative deep and cigs slow to mix. .Monday Night through Wednesday... The slow-moving upper trough will continue to approach the region with increasing chances for SHRA/TSRA, with both a severe and +RA/TSRA threat. 05/ && .SHORT TERM... /Issued 249 PM CDT Sun Mar 25 2018/ /Rest of the afternoon through Monday/ Surface analysis this afternoon places a warm front just north of the Red River, near a Hugo to Ardmore line before it curls southwest to near Wichita Falls. From here, it meets up with a dryline which extends southward to just west of a Graham to Cisco line. Surface convergence appears to be maximized in the vicinity of this triple point in a region bounded by a Bowie-Burkburnett-Olney line based on the latest LAPS analysis. Given the lack of more appreciable large-scale forcing for ascent today (mid-level height tendencies are either neutral or slightly positive) as the main upper-low is still just now dropping into the Great Basin, these mesoscale areas of enhanced convergence will be the only mechanism to force thunderstorm development today. The farther south along the dryline you go, the weaker surface convergence becomes, and thus the lower the prospects for convective initiation. While 850 mb temperatures are currently running in the 17-19C range across our western counties, clearing skies have allowed surface temperatures to jump into the upper 80s/lower 90s across this part of the region, which is helping to diminish lingering mixed-layer convective inhibition (MLCINH). While this morning`s deterministic guidance remained quiet along the dryline, the TTWRF ensemble seems to have caught on to the increased low-level lift near the triple point and the reducing in MLCINH, and roughly 75 percent of the 41 ensemble members now convect in this favored area during the 4-5 PM timeframe. Recent runs of the HRRR are also indicating a similar convective evolution later this afternoon. Recent visible satellite trends also reveal a small area of increasingly agitated/towering cumulus developing in this aformentioned zone near the triple point. As a result, it appears as if a storm (or two) may try to develop here in the next 1-2 hours as surface temperatures continue to warm. Effective deep layer shear values in excess of 50 kts would certainly support a supercellular mode, and very large CAPE profiles through the hail growth zone would indicate a threat for large or very large hail (golfballs or larger) as any storm tracks initially to the east. It`s entirely possible that storms move along and just north of the Red River, but any deviant rightward motion would bring the threat for severe weather into our northern counties. At this time, it appears the favored corridor for some a severe threat exists in a region bounded by a Bowie to Denton to Sherman line. Storms will likely decay to the east as they encounter increasing nocturnal inhibition/capping later this evening. The threat for a tornado, while low, cannot be discounted here given very high low- level instability which can at times offset otherwise marginal low-level wind fields (which we have in this instance). Even if a storm or two develops here, it`s unclear whether convective vigor will be maintained given the lack of better forcing and increased capping off to the east, but we`ll continue to monitor this threat closely over the next few hours. Late tonight, isentropic ascent will increase across the Concho Valley. This could result in the development of scattered showers/storms rooted above the base of the EML plume. With steep (7.5-8 C/km) lapse rates in place and 35-40 kts of effective shear, can`t rule out some marginally severe hail in the strongest storms as they track northeastward. The main corridor for overnight/early Monday morning activity looks to be north and west of an Eastland to Sherman line. Aside from breezy southerly winds tomorrow, most of the day Monday looks to be relatively quiet on the weather front as low cloud cover gradually erodes through afternoon. The dryline will mix back eastward into the Rolling Plains and should reload for another round of convection by late in the afternoon. A bit more forcing for ascent will be present on Monday, so storm coverage will likely be higher than today (Sunday). Carlaw && .LONG TERM... /Issued 249 PM CDT Sun Mar 25 2018/ /Monday night through Sunday/ Rain and thunderstorm chances will increase Monday night as the deep upper low rotates through the Desert Southwest and moist large scale ascent increases. A few severe storms will be possible across the northwest zones during the evening hours near an approaching dryline and cold front. Storms should become more numerous overnight Monday through Tuesday as the cold front slides into the region. The front will not pack much of a punch as far as modifying the airmass but will provide an additional source of lift. Confidence is high that rain and thunderstorms will be numerous Tuesday but we are less certain of exactly where the cold front will stall and therefore where the best potential for strong/severe storms will be. It still appears that the most likely area will be southeast of a line from Cisco to Sherman, but again it will all depend on where the front ends up. Numerous thunderstorms are expected Tuesday night through Wednesday night as the upper low opens up and translates to the east. Since ample moisture and lift will both be present, the potential for heavy rainfall and flooding will increase, especially across the southeast half of the area. For now we will hold off on any type of Flood/Flash Flood Watch since the heaviest rainfall is still a couple of days out and the amount and exact location are still in question. Best estimates on rainfall totals still appear to be in the 2 to 3 inch range but higher amounts are possible in some localized spots. The main upper trough axis should swing through the region overnight Wednesday through Thursday which will bring decreasing rain/storm chances from west to east with precip ending across the entire forecast area Thursday night. Zonal flow aloft will set up behind the departing upper trough and result in relatively quiet weather Friday through Easter Sunday. A cold front is progged to move into the region Sunday night through Monday which may result in a few showers and storms. Mild temperatures are expected through the week with highs generally in the 70. The only exception will be a slight cool down Wednesday/Wednesday night behind the cold front. 79 && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 67 80 68 72 58 / 10 20 50 80 70 Waco 67 82 67 77 60 / 10 20 30 60 80 Paris 63 78 65 72 55 / 10 30 50 80 80 Denton 66 79 65 71 55 / 20 20 60 80 60 McKinney 66 79 67 71 55 / 10 20 50 80 70 Dallas 68 81 67 73 58 / 10 20 50 80 70 Terrell 66 81 67 75 58 / 10 20 40 70 80 Corsicana 66 82 67 78 60 / 10 20 30 60 80 Temple 66 83 67 78 60 / 10 20 20 50 80 Mineral Wells 66 81 62 70 53 / 20 40 60 70 60 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$ 05/26
Area Forecast Discussion
National Weather Service Green Bay WI
620 PM CDT Sun Mar 25 2018 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Monday Issued at 226 PM CDT Sun Mar 25 2018 The latest RAP analysis and satellite/radar imagery show a large area of high pressure stretching from northern Quebec to the western Great Lakes early this afternoon. An area of cirrus is moving across the region, above a very dry airmass with dewpoints falling to around 5 above over Vilas county. Temperatures have been slow to warm so far today, with readings mostly in the 30s. Looking out west, light precip is occurring over the eastern Dakotas to eastern NE/KS, with a swath of returning moisture. As the high pressure system departs and a storm system moves towards the region on Monday, precip chances are the main forecast concern. Tonight...The ribbon of moisture return will remain west of the region over Minnesota and the eastern Dakotas. Meanwhile, high pressure and associated very dry air will remain present over north-central and northeast WI. Will see periods of mid and high clouds pass over north-central WI during the evening. These clouds should spread east overnight and lower at the same time. With some clouds and a persistent southeast wind, temps will be warmer than last night with lows ranging from around 20 over Vilas county to the upper 20s near Lake Michigan. Monday...Clouds will continue to increase ahead of a storm system that will be developing over the northern and central Plains. Dry air below 700 mb will initially be tough to overcome, so slowed down precip chances during the afternoon. Most likely looking at precip chances ramping up after 4 pm over central and north-central WI. With the incoming cloud cover and east winds, lowered max temps, especially over east-central WI. Highs should range from the low to mid 40s for much of the region. .LONG TERM...Monday Night Through Sunday Issued at 226 PM CDT Sun Mar 25 2018 Medium range models remain consistent with a widespread one half inch rainfall Monday night. Expect primarily rain, but cool dry air mass lingering over northern Wisconsin and far northeast wisconsin Monday evening may generated a brief mix due to evap cooling. Added a fog mention later Monday night as winds decrease with the frontal passage and surface dewpoints climb into the 30s to lower 40s over at least east central Wisconsin and the lakeshore region. Trend of the departure of the system with cold front is a bit quicker Tuesday, with precipitation east of the area by Tuesday afternoon. With southwest flow aloft, milder conditions will continue for a short time from Tuesday into Wednesday. There is chance of precipitation late Wednesday into Thursday as a cold front drops through. The air will turn cold enough Thursday for the precipitation type to be a mix or all light snow. This cold front will also be the start of trend to below normal temperatures for the rest of the week and into next weekend. Timing of pieces of energy carving out the broad cold upper trough setting up over the northern tier of the country will produce additional precipitation chances. Timing of these systems is difficult but current temperature profiles are supporting mainly snow. && .AVIATION...for 00Z TAF Issuance Issued at 615 PM CDT Sun Mar 25 2018 Generally good flight conditions are expected for the next 18 hours, though there will be some low-end LLWS overnight. A sharp downward trend in ceilings will begin tomorrow afternoon and continue into tomorrow night as precipitation spreads across the area from the west. More significant LLWS is anticipated at that time as well. && .HYDROLOGY... Issued at 226 PM CDT Sun Mar 25 2018 Progs continue to paint around a half inch of rain Monday night for the forecast area. Latest forecast river guidance with present qpf forecasts indicate main stem rivers overall remain below bankfull for this event. Still anticipate some run off issues to affect small streams and creeks due to snow cover and or lingering frost in the ground. But this rain should aid with removing some of the frost in the ground. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......TDH AVIATION.......Skowronski HYDROLOGY......TDH
Area Forecast Discussion
National Weather Service Huntsville AL
919 PM CDT Sun Mar 25 2018 .NEAR TERM...(Tonight) Issued at 919 PM CDT Sun Mar 25 2018 A rather complex pattern prevailed across the eastern lower-48 this evening. The main player is a wedge or backdoor cold front moving southward along the SE coast. This front earlier produced some rather dramatic temperature falls near the Atlantic coast in the afternoon, showing that winter`s cold is quite not over with given very chilly north Atlantic water temperatures. The cold wedge also created a wider than usual range in high temperatures locally - ranging from the low/mid 70s in southern Cullman county to only 61 in Ft Payne. The higher terrain just to the east of Huntsville until recently had slowed the process of that cold air making it to the Huntsville area. Although winds in the valley locations were mostly less than 12 mph, SE winds were gusting to over 20 mph in Monte Sano east of Huntsville and a thousand feet higher. The cold push from the east will result in winds becoming easterly, then SE, and increasing into the 10-20 mph range during the overnight. Further aloft, an approaching upper level system from the west was producing light showers across parts of MO/AR and the Mid South. A WNW flow aloft along with increasing upglide in the lower levels will bring these showers across the Tennessee Valley during the later evening and overnight. With cold air replacing a more unstable airmass that was at the surface, only shower and no thunder is expected. Generally followed an HRRR solution (with adjustments) regarding the placement and timing of showers tonight. The low temperatures forecast tonight looked OK, did not make any changes here. But did increase wind speeds a tad, especially the gusts in the overnight as the cold air becomes more predominate. .SHORT TERM...(Monday through Tuesday) Issued at 221 PM CDT Sun Mar 25 2018 The aforementioned boundary will push back to the east on Monday in response to an upper-ridge axis building in from the southwest. Scattered showers will be possible along/near this boundary early Monday morning -- with the best chances shifting east (with the boundary) through the day. However, given the fairly dry boundary layer, QPF amounts will be light as some of the precipitation will evaporate before reaching the surface. In wake of the front, a stable air mass will remain in place, with 2-3kft decks of low stratus persisting throughout the day. Thus, temperatures will struggle to climb much above the mid to upper 50s. In fact, areas along the AL/GA may struggle to climb above 50 degrees for the second straight day! The upper-ridge will continue to build into the region Monday night into Tuesday, promoting a gradual wind shift to the south and southwest. The flow will likely help to erode the low-level stratus decks with time by midday Tuesday, but increase boundary layer moisture, setting the stage for a prolonged rainfall event late this week (see long term section below). For Tuesday, think that the lack of any lifting/forcing mechanism will significantly limit precipitation chances and have taken out mentionable PoPs in the forecast. Given the southerly flow and some breaks in the cloud cover, highs in the mid 60s to around 70 degrees will be possible (about 10 degrees warmer than Monday). .LONG TERM...(Tuesday night through Saturday) Issued at 221 PM CDT Sun Mar 25 2018 A strengthening upper-low pressure system over Texas will gradually force the upper-ridge to the south and east of the Caribbean. A slow moving cold front will gradually progress from the Great Plains into the Mississippi and eventually Tennessee River valleys on Wednesday through Friday, setting the stage for a prolonged rain event across the region. Although there are still some model differences on when the period for heaviest rainfall will occur, all model solutions hint at a slow/stalled boundary across the region during this time period. The GFS is a little faster in bringing heavier rainfall in than the ECMWF and Canadian solutions -- and the ECMWF and Canadian models keep the heavy rainfall potential in longer on Friday. Regardless of these differences, confidence is increasing that heavy rainfall and potential flash/areal flooding threat will exist late this week, with possible river flooding lingering into the weekend. Ahead of this front on Tuesday night and Wednesday, deep southwest flow will continue to advect rich Gulf moisture into the region. This can be seen in forecast PWATs which jump from around 0.75" (00z Wednesday) to 1.5" (00z Thursday) at KHSV. A couple of weak shortwaves rounding the broadening upper-trough will provide enough lift to generate showers (and even a few thunderstorms) Tuesday night and especially during the day on Wednesday. Coverage may vary significantly across the region, with areas west of I-65 (which will be closer to the boundary) seeing much better chances through midday Wednesday. However, as the boundary sags into the region Wednesday night into Thursday, it is progged to stall from the Plateau region of Middle Tennessee and through Northern Alabama and Central Mississippi. The boundary will serve as a focus for moderate heavy showers and thunderstorms from Wednesday night through early Friday morning. As one might expect, there are several ingredients that are beginning to line up for heavy rainfall and flooding during this Wednesday to Friday period. First, the presence of a boundary with a deep, moisture fetch off the Gulf of Mexico moving parallel to the boundary. This would support the generation of deep convection that would potentially train over the same areas. Secondly, abundant tropical moisture will be present, with PWATs around 1.5-1.6". These PWATs would place the area in the 99th percentile for late March. A deep warm cloud layer was noted on model soundings, with some modest CAPE that would allow for sustained updrafts and some weakly organized convection. Thus, we`ll need to watch for a flash/areal flood threat in the Wednesday night to Thursday night timeframe and then the possibility for river flooding thereafter should these projections/trends continue. Have increased storm total QPF a bit to go along with the latest WPC thinking. Would not be shocked to see 2 to 4 inches of rain across the region from 00z Wednesday through 12z Friday (should the boundary stall over the area), with locally higher amounts possible. This heaviest band of precipitation will be very dependent on where the boundary stalls and that`s still uncertain at this time. The front will gradually move east Friday into Friday night as high pressure builds in from the northwest. This will result in a cooler, but dry start to the Easter holiday weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 649 PM CDT Sun Mar 25 2018 A rather strong west to east temp difference continued across the region, with 6 PM readings around 50 over our eastern areas, to mid 60s over the NW and central areas. A north to south oriented boundary, or wedge type front located east of Huntsville will gradually move westward this evening, bringing colder temps and a wind shift. Along with a temperature fall, lower clouds will produce MVFR CIGs ~1800 ft AGL at KHSV in the next couple of hours, and CIGs lowering at KMSL late in the evening. Winds will become east, then SE tonight, increasing into the 10-15kt range, with gusts above 25kt possible especially east of I-65. Sustained winds around 35kt 2000 ft AGL are too low to warrant Low Level Wind Shear this issuance. Have CIGs improving to VFR Monday afternoon, but staying MVFR at KMSL into the latter hours of this TAF. && .HUN WATCHES/WARNINGS/ADVISORIES... AL...NONE. TN...NONE. && $$ NEAR TERM...RSB SHORT TERM...AMP.24 LONG TERM...AMP.24 AVIATION...RSB For more information please visit our website at
Area Forecast Discussion
National Weather Service Wichita KS
905 PM CDT Sun Mar 25 2018 .UPDATE... Issued at 904 PM CDT Sun Mar 25 2018 Latest IR satellite (meso 1) images and sfc obs show low clouds and visibilities beginning to decrease for areas just south of the Kansas/Oklahoma border. This stratus deck and increasing moisture, will continue to surge north for the late evening hours, overspreading most of south central and central KS after midnight. The further north the moisture gets, the easterly wind component and upslope flow will enhance the low clouds/and fog potential, especially for areas west of I-135. SREF model data and bufkit soundings seem to support this, with a stratus build down type scenario. Think patchy dense dog will be possible, with visibilities dropping to 1 to 3 miles, with some locations seeing 1/2 mile visibilities. So have decided to issue a dense fog advisory for areas mainly west of a KRSL to KHUT to KICT line, or generally for areas west of I-135. Will also add some drizzle to the forecast as well. As the low level moisture transport increases after midnight, an elevated unstable airmass will also lift north into south central KS as well. Latest RAP model shows elevated CAPE values of 1500-2000 J/kg pushing into the area. Isentropic lift also increases, which suggests that showers and thunderstorms may also develop after midnight, initially over south central KS, and quickly lift NE, as the moisture transport lifts NE into NE KS early on Mon morning. Some uncertainty on how many storms will be possible over south central KS, as bufkit lapse rates above the saturated low layers aren`t too steep. Think areas NE of KICT will see the most storms, with a few strong to possibly severe storms during the early morning hours on Mon, given the above mentioned instability and bulk shear of 50-60 kts. Ketcham && .SHORT TERM...(This evening Tuesday) Issued at 327 PM CDT Sun Mar 25 2018 Precipitation chances/coverage and temperatures are the biggest challenges of the forecast for the first part of the week. The latest resolutions for precipitation show development not really until after midnight. Adjustments have been made to this field in order to account for the latest guidance. Instability does increase this evening into the overnight hours. Thus it is still possible there could be a couple of strong to severe storms. The Storm Prediction Center has expanded their marginal risk to encompass the entire forecast area. This threat would be for primarily hail in the overnight hours. While there is an inflow of warm air advection, the question is how will the cloud cover and precipitation impact the temperatures. A tight gradient is possible with the models differing in their resolutions for high temperatures. The swing is about 20 degrees between the GFS and NAM across central Kansas. It seems that the cooler solution has been on the winning side of this match up. Thus this was the choice for that area. South central Kansas appears to stay in the warm sector. Breaks in the clouds could be seen to aid the daytime heating. There is definitely the potential for a bust in either direction. Showers and thunderstorms remain possible throughout the day on Monday. There is the potential for an isolated strong to severe thunderstorm in the afternoon and evening. As mentioned in the previous discussion, the daytime heating factor will play into stability of the atmosphere. .LONG TERM...(Tuesday Night through Sunday) Issued at 327 PM CDT Sun Mar 25 2018 Medium range models are in relative agreement that, during the middle of the week, a moderate PV anomaly moves into the western and central US. This system will bring additional moisture and precipitation to the region. The main challenge with this system is the uncertainty with the location of the front. Quite confident that precipitation will occur. The location of the front will drive the threat of severe weather. Currently, only the extreme portion of southeast Kansas may expect any severe weather, and that chance is small at best. On the tail end of the system as it passes is another disturbance that could bring additional precipitation Thursday. Some of this may be snow in central Kansas based on forecast soundings and cool surface temperatures Thursday night and into early Friday. A third disturbance will begin having influence over the region over the weekend and early next week. Strong southerly flow Saturday ahead of a developing over the High Plain may bring a few showers in the are of isentropic ascent across Kansas. Storms chances increase in earnest Sunday and Monday as the front moves through. Behind the front, some of the precipitation may change to snow, mainly across central Kansas. Overall, the pattern is increasing in activity. With that, temperatures are expected to be mainly below normal which will suppress severe weather chances. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 658 PM CDT Sun Mar 25 2018 Easterly surface flow will lead to lots of upslope flow for the overnight hours, especially for areas east of the I-135. Increasing low level moisture transport, in combination with this upslope flow, will lead to deteriorating aviation conditions late this evening and overnight, especially for areas west of I-135 where terrain influences will be enhanced. This will lead to Cigs for most of the south central and central KS TAFS dropping to IFR/LIFR. The moisture transport and increasing elevated instability will also lead to increasing chances of SHRA/TSRA across most of the region after 06z/Mon. So will go with VCTS for most locations from 06-10z and go with tempo groups for TSRA. Could also see some MVFR vsbys in and around the stronger storms. Ketcham && .FIRE WEATHER... Issued at 327 PM CDT Sun Mar 25 2018 Pattern becoming more active for precipitation over the next week. No strong winds really to speak of until next weekend ahead of the next system. Even then, the GFDI only gets into the moderate category. && .PRELIMINARY POINT TEMPS/POPS... Wichita-KICT 51 67 44 52 / 60 40 30 30 Hutchinson 48 60 41 52 / 60 40 20 20 Newton 48 62 42 51 / 60 50 30 30 ElDorado 49 66 44 52 / 60 50 40 40 Winfield-KWLD 52 71 47 53 / 60 40 50 50 Russell 45 49 37 55 / 50 30 10 10 Great Bend 46 51 38 53 / 50 30 10 10 Salina 47 52 40 54 / 70 50 20 20 McPherson 47 56 40 52 / 60 50 20 20 Coffeyville 53 67 52 56 / 80 60 80 70 Chanute 49 65 48 52 / 70 70 70 70 Iola 47 64 47 51 / 70 70 70 60 Parsons-KPPF 51 66 51 55 / 80 60 80 70 && .ICT WATCHES/WARNINGS/ADVISORIES... Dense Fog Advisory until 9 AM CDT Monday for KSZ032-047-050-067- 082-083-091-092. && $$ UPDATE...Ketcham SHORT TERM...VJP LONG TERM...KRC AVIATION...Ketcham FIRE WEATHER...KRC
Area Forecast Discussion
National Weather Service Jacksonville FL
805 PM EDT Sun Mar 25 2018 ...Locally Heavy Rainfall I-10 Corridor Northward This Evening... ...Breezy and Cooler with Rough Surf Conditions... .UPDATE...Backdoor cold front bringing much cooler and windy conditions is now pushing sw across ne Fl this evening. Training showers are producing heavy downpours and will continue this evening along and behind front with help of upper impulse in nw flow aloft. Rainfall amounts of one half to one inch may occur near the I-10 corridor. Isolated thunder occurred earlier with daytime heating but lightning activity has now decreased as instability fades. Expect shower activity to decrease after midnight as HRRR model indicates. && .AVIATION...IFR conditions will persist tonight through Monday as low clouds and showers behind backdoor cold front linger over the area. NE winds will be around 15 knots with gusts up to 25 knots near the east coast. && .MARINE...Surge of ne winds and building seas have spread south across the waters this afternoon and evening in wake of backdoor cold front. Occasional gusts to Gale force may occur over the waters through Monday. Advisory conditions will continue into midweek as strong high pressure builds south and swells persist. Rip Currents: High risk expected through Monday and Tuesday due to strong onshore winds and rough surf. && .PRELIMINARY POINT TEMPS/POPS... AMG 49 58 53 70 / 30 10 10 10 SSI 51 57 56 66 / 30 20 20 10 JAX 55 62 58 72 / 80 20 20 0 SGJ 58 65 62 71 / 80 30 20 0 GNV 56 67 59 78 / 50 10 10 0 OCF 57 72 60 79 / 30 10 10 0 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...Small Craft Advisory until 10 PM EDT Wednesday for Waters from Altamaha Sound GA to Fernandina Beach FL from 20 to 60 NM- Waters from Fernandina Beach to St. Augustine FL from 20 to 60 NM-Waters from St. Augustine to Flagler Beach FL from 20 to 60 NM. Small Craft Advisory until 10 AM EDT Tuesday for Coastal waters from Altamaha Sound to Fernandina Beach FL out 20 NM- Coastal waters from Fernandina Beach to St. Augustine FL out 20 NM-Coastal waters from St. Augustine to Flagler Beach FL out 20 NM. && $$ Zibura/Sandrik/Shashy
National Weather Service Jackson KY
1025 PM EDT Sun Mar 25 2018 .UPDATE... Issued at 1025 PM EDT SUN MAR 25 2018 Forecast soundings show a very shallow layer of elevated convection for the western portion of the forecast area tonight into Monday. However, models also showed light precip should already be to our southwest over TN this evening, but it has not materialized yet. In light of reality to this point, have trimmed back the POP to no more than 10%, but held on to the possibility of sprinkles over the western fringe of the forecast area late tonight into Monday morning. UPDATE Issued at 854 PM EDT SUN MAR 25 2018 Valley temps are dropping off quickly in the northeast part of the forecast area where snowcover looks like it survived through the day. However, clouds are also moving in from the southwest. Have made temperatures adjustments for colder readings in the northeast valleys this evening, but allowed for ridge/valley equalization overnight under what should become overcast conditions. && .SHORT TERM...(This evening through Monday night) Issued at 320 PM EDT SUN MAR 25 2018 18z sfc analysis shows an inverted trough of low pressure to the south with high pressure over the northern parts of the Ohio Valley. The gradient between these two features is making for east to northeast flow of winds - around 10 mph with occasional gust to 20 mph - that are slightly downsloping across the area. As a result, most of eastern Kentucky enjoyed sunny conditions today - aside from the high clouds over southwest parts of the Cumberland Valley. This has helped to clear out some of the snow from yesterday in the north, but temperatures were hindered there due to the melting there. Subsequently readings ranged from the lower 40s north to the mid/upper 50s south with dewpoints likewise varying from the low/mid 20s north to the lower 40s south. The models are in good agreement aloft through the short term portion of the forecast as they all depict a dirty ridge passing over the Ohio Valley with dampening energy riding through Kentucky tonight and during the day Monday. This is in the wake of the deep trough pulling away well to the east this evening taking the stronger shortwave impulses along with it. For Monday night the ridge axis will move through eastern Kentucky allowing southwest flow to start to bring more mid level energy into the state, just to our west, through the night and into Tuesday morning. Given the good model agreement have favored a general blend with lean on the higher resolution NAM12 and HRRR in the near term for details. Sensible weather will feature moisture returning back into eastern Kentucky from the southwest. This will bring in an increase in cloud cover tonight from southwest to northeast with even some sprinkles or a light rain shower possible. To the north, skies will remain clear enough over the remaining snow cover to drive temperatures toward freezing before the area is overrun by the thickening clouds. Pockets of sprinkles or a stray light rain shower will be possible in the west on Monday beneath the thick cloud deck. By evening, a warm front will be lifting through Eastern Kentucky with a better chance of rain showers for the area as it tracks northeast that night. The clouds tonight and Monday night should keep much of any fog (or frost) at bay through the period despite the ample boundary layer moisture. Used the CONSShort and ShortBlend as a starting point for all the grids with only minor adjustments to temperatures - aside from lowering the snow cover areas tonight. As for PoPs tried to reign in the sprinkles and light showers tonight and Monday - keeping them mainly in the western parts of the CWA closer to the low pressure and developing warm front. .LONG TERM...(Tuesday through Sunday) Issued at 431 PM EDT SUN MAR 25 2018 The models remain in general agreement with an amplified split- flow pattern to rule across the CONUS through the end of the work week, before phasing and then transitioning to a more zonal flow pattern into the weekend. Ridging will get shoved to the Eastern Seaboard by mid-week, as a broad trough gradually moves across the Mississippi Valley. This will allow for a northeast to southwest oriented baroclinic zone to take shape from the Ohio Valley down to the Arklatex region. This boundary will then slowly move southeast, yielding another extended period of unsettled weather across our area. A warm front will be lifting northeast across the area Tuesday morning, bringing the threat of showers through at least the first half of the day. The surface cold front will then move in from the northwest Tuesday night into Wednesday, bringing more widespread showers to the area. This boundary will get hung up in the vicinity of the region, with another surge of moisture and lift occurring Thursday into Friday. There still remains disagreement on the evolution of smaller scale features during this time frame, with the ECMWF remaining slower, while the GFS stays progressive. Either way, will continue to monitor QPF trends, as multiple rounds will allow for a threat of excessive runoff eventually for some locations. Generally drier weather can be expected through most of the weekend, with another front approaching from the northwest by late Sunday. Temperatures will average near to slightly above normal through Friday, before cooling down slightly into the weekend. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) ISSUED AT 737 PM EDT SUN MAR 25 2018 VFR ceilings mostly in the 3500` to 5000` range are currently affecting the southwest portion of the forecast area around KEKQ, K1A6, KSME, and KLOZ. Those ceilings will spread northeast over the rest of the forecast area by around 06Z, and generally persist through the remainder of the forecast period. Ceilings could dip to MVFR levels tonight around KEKQ. Winds will be from the northeast to east this evening, and become southeasterly overnight. Speeds through the period will generally be less than 10 kts. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...HAL SHORT TERM...GREIF LONG TERM...GEOGERIAN AVIATION...HAL
Area Forecast Discussion
National Weather Service Louisville KY
812 PM EDT Sun Mar 25 2018 .Forecast Update... Issued at 810 PM EDT Sun Mar 25 2018 Inverted surface trough was draped SW to NE through Middle Tennessee this evening. Looking at the 925-700 mb layer, a subtle wave over the OH/TN valleys is resulting in isentropic lift and mid-level clouds. Low clouds were still confined near and south of the TN border, closer to the low-level trough. This weak boundary slides north overnight. With weak lift, latest HRRR runs have featured sprinkles moving south to north through the area through sunrise. Other than some sprinkles Monday morning, the first half of the day looks largely dry. So only forecast change this evening was to delay precip chances until early to mid-afternoon. A warm advection band of precip is likely to move into the western CWA after 20z Monday. && .Short Term...(This evening through Monday night) Issued at 257 PM EDT Sun Mar 25 2018 Skies this afternoon range from partly cloudy across southern IN and north central KY to mostly cloudy over south central KY. Temperatures range from the mid to upper 40s. A few radar returns showing up across south central KY are likely resulting in some sprinkles. For tonight, and inverted surface trough currently across east central KY will shift back to the west tonight and end up over central KY. Convergence along this trough will result in sprinkles and isolated showers across the region overnight. Clouds and winds shifting to southeasterly will limit the temperature fall. Lows will bottom out in the mid 30s to lower 40s. On Monday a warm front will approach and move north across the region. Scattered to numerous showers will accompany this front as it moves through Monday afternoon into the overnight hours. Highs on Monday will be in the mid to upper 50s. Lows Monday night will drop only into the mid to upper 40s. .Long Term...(Tuesday through Sunday) Issued at 310 PM EDT Sun Mar 25 2018 The long term period will start out warmer as much of the lower Ohio Valley will reside in the warm sector of an approaching system. Showers and potentially a few thunderstorms will be possible, particularly over southern IN. Rain chances will fall off the farther south and east you go in central KY Tuesday. Highs will top out in the 60s. The best chance for widespread rain will be Tuesday night into Wednesday as the cold front associated with the system mentioned above slowly moves through. Precipitable water values near 1.5" will result in moderate to possibly some heavy rainfall. Precipitation chances will decrease on Wednesday night, but an upper level wave will approach towards the morning hours Thursday. This will try to phase with the stalled frontal boundary to the east and bring another round of potentially soaking rain Thursday into Thursday night. This rain may last into Friday as well and end as a bit of a wintry mix. However, models are very inconsistent on this solution, so confidence in the amount of precipitation for Friday is low. Overall, area wide 1-2.5 inch rainfall amounts with some higher values can be expected next week. This may lead to some rises on the smaller area rivers and potentially some minor flooding. && .Aviation...(00Z TAF Issuance) Issued at 740 PM EDT Sun Mar 25 2018 A few sprinkles or very light rain showers can be expected tonight into tomorrow morning under very weak isentropic lift near a boundary to our south. Flight conditions will drop from VFR to MVFR tonight at BWG and tomorrow morning at HNB/SDF/LEX as better low level moisture pushes in from the south. Expect a breezy day tomorrow with southeast sfc winds of 10-14 kts with gusts to around 17-20 kts. A return to VFR is possible from late morning through early afternoon before better rain shower chances and MVFR conditions move in for late afternoon into the evening hours. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...EBW Short Term...EER Long Term...EER Aviation...AMS
Area Forecast Discussion
National Weather Service Mobile AL
641 PM CDT Sun Mar 25 2018 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION... 26/00Z issuance...VFR conditions will continue through late this evening, but low clouds and fog develop and become more widespread across the region by around 26/06z. IFR ceilings and surface visibility expected across parts of the region overnight. The IFR ceilings will then likely persist through most of the day on Monday, and while surface visibility remains somewhat limited through the day due to patches of light advective sea fog, visibility should be no lower than MVFR. Light southeasterly flow continues, moderate at times Monday afternoon, especially near the coast. 12/DS && .PREV DISCUSSION... /issued 402 PM CDT Sun Mar 25 2018/ NEAR TERM /Now Through Monday/...Taking a look at the current situation over the area, am seeing a few radar returns over northeastern parts of the forecast area. Am also seeing the coming backdoor front northeast of Maxwell radar. This front is being pushed across the Southeast by an upper system wobbling around off the New England Coast, and at this point is fighting a general westerly low level flow due to surface high over the central Gulf of Mexico. A cap on the latest LAPS analysis and RAP initialization situated around 700mb has been helping to limit development attm, though. Ahead of the front tonight, have left in showers mainly over the northern half of the area, with the current activity expected to last into the evening. How far south/southwest the showers/storms spread depends on how strong the cap remains. At this point, with southern parts of the forecast area seeing the least amount of heating today, this portion has the least amount of instability. As the front moves over the forecast area late tonight through Monday, am expecting showers to move southwest/west across the forecast area, with any residual showers along the western border or west of the area. With instability still in place on the model soundings, feel any thunder mixing in will be very limited after midnight. With a moist atmosphere in place, put in light fog ahead of the front, over the southwestern half of the forecast area. Now for the challenging part of the forecast, temperatures. With significantly cooler air moving over the forecast area behind the front, a significant southwest to northeast temp gradient results. For tonight, the gradient isn`t as pronounced, with lows ranging from low 50s northeast to low 60s southwest and along the coast. For Monday, as the colder air overspreads the forecast area, a 13 degree spread in highs is expected, ranging from well below seasonal northeast to around seasonal southwest. /16 SHORT TERM /Monday night Through Wednesday night/...Will start off this period with a short-wave upper ridge positioned from the Gulf, northward up across the Appalachians while a positive tilt upper level trof digs into the four corners of the Desert southwest. This pattern mostly holds thru Tuesday. At the surface, a large pressure ridge expands over the southeast US. The larger scale subsidence, with the upper ridge in place, keeps the chances of precipitation low (10 to 20%) Monday night thru Tuesday night. Moving into Wednesday, the ridge aloft slips more eastward with the local area coming under more of a southwest flow aloft. In this flow pattern, the passage of a series of impulses, when interacting with deep moisture and daily instability favors potentially more of a chance of showers and perhaps a few storms over the far western zones, to a slight chance closer to the I-65 corridor Wednesday. Patchy night-time fog possible Monday night and Tuesday night. Temperatures gradually moderating. /10 LONG TERM /Thursday Through Sunday/...Cold front is forecast to approach from the west and make passage by Thursday night. Global spectral solutions on the timing of the front diverge more greatly going into Thursday night with the 25.12Z GFS more progressive/fast than the ECMWF. Despite the uncertainty, both solutions continues to support higher pops for the area as the front approaches and moves through. Will have likely to categorical pops for Thursday along and west of I-65 with good chance pops further to the east. For Thursday night, will have likely pops for the entire area. For Friday, will have slight chance to chance pops for roughly the eastern half of the area for lingering precipitation in the wake of the front, then dry conditions follow. A slight chance of showers return by Sunday. /29 Confidence on strong to severe storms for Thursday is low at this time, also given the uncertainties given different outcomes on progression of best instability and jet streaks in the longer range guidance. /10 MARINE...A front will cross the area later tonight through Monday from the northeast, switching the light, general southwest to westerly flow to strong easterly. As the post-frontal surface winds shift southeast along the coast, the winds over area coastal waters will shift to southerly by Thursday. A front is expected to cross the coastal waters Thursday night into Friday. Timing has been inconsistent with this fropa, with a slow shift to later periods in the week, so have less confidence with timing at this point. /16 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...High Rip Current Risk through Monday morning for ALZ265-266. FL...High Rip Current Risk through Monday morning for FLZ202-204-206. MS...None. GM...Small Craft Advisory from 7 PM Monday to 1 PM CDT Tuesday for GMZ630>636. Small Craft Advisory from 7 AM Monday to 9 AM CDT Wednesday for GMZ650-655-670-675. && $$ This product is also available on the web at:
Area Forecast Discussion
National Weather Service Nashville TN
814 PM CDT Sun Mar 25 2018 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Latest radar imagery and surface observations indicate light showers and drizzle that were affecting much of Middle Tennessee have ended for now. However, latest HRRR indicates showers along the TN/AR border will spread eastward into our southwest counties later this evening and overnight, where chance pops are already in place. Cannot rule out a few showers or drizzle across the rest of the area overnight as well due to the very moist low levels trapped beneath the extreme low level temperature inversion around 3000 ft shown on the 00Z OHX sounding. Forecast is generally on track and just made minor tweaks based on latest obs and HRRR runs. && .AVIATION... 00Z TAF DISCUSSION. Winds have shifted from northerly to southerly at CSV. Expect all taf sites to follow suit as the evening progresses. Cigs should remain within MVFR and IFR range overnight tonight with visibilities remaining mainly VFR. There is the chance that some light showers may form and move north through Middle Tennessee later tonight. They should be isolated, so haven`t included them in this issuance. The better chance of showers will be Monday afternoon as a system moves from west to east across the area. Have left vcsh in the forecast for CKV, and will likely add it to the other sites with the next forecast. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......Shamburger AVIATION........11
Area Forecast Discussion
National Weather Service San Angelo TX
643 PM CDT Sun Mar 25 2018 .AVIATION... /00Z TAFS/ IFR to MVFR stratuS returns over most terminals from southeast to northwest overnight, then rising/scattering out to VFR towards or just after noon. KABI is the exception, with stratus staying just south and east. An isolated shower or thunderstorms is possible tonight and Monday morning, but potential will be increasing after 21Z Monday, and especially towards 00Z Tuesday. Added VCTS at KABI and KSJT 21Z Monday. && .PREV DISCUSSION... /issued 248 PM CDT Sun Mar 25 2018/ SHORT TERM... (Tonight and Monday) The forecast is somewhat problematic with rain chances tonight and Monday. Our area will be under fairly strong southwest flow aloft, as an upper trough deepens into the southwestern part of the country on Monday. The dryline has mixed farther east this afternoon across the northern part of our area, and less across the south. At San Angelo (west of this dryline), the temperature has reached 93 degrees so far this afternoon, tying the record high for this date (set in 2011). Anticipate that with additional heating, this this record will be broken. By late afternoon, expect the dryline to extend from near Throckmorton to Coleman to just west of Sonora. Despite MLCAPE values of 1500-2500 J/kg just head of the dryline, not anticipating thunderstorm development along it given the cap strength and fairly weak convergence. The dryline will retreat to the west across west central Texas this evening and early tonight. Development of a weak low-level jet will aid in low-level moisture transport across our area tonight. The models vary considerably tonight and Monday with rain chances, with the 12Z NAM much drier than the GFS. The HRRR has been dry for this evening and tonight in our area, while the 12Z TTU WRF indicates scattered convective development late tonight into Monday morning across the Big Country area along and north of I-20. While not readily apparent on satellite imagery, if an embedded disturbance in the aforementioned southwest flow aloft enters our area, the chance for shower/thunderstorm development would be increased. The mid-level lapse rates for tonight and forecast instability on Monday, combined with favorable vertical shear, are supportive of strong to severe thunderstorms should development occur. At this time, we are keeping PoPs on the low side (20-30 percent). Looks like the better chance will be toward Monday evening, with the dryline expected to be just west of our area. Temperatures will remain well-above normal tonight and Monday. Lows tonight are expected to be mostly in the mid 60s, with highs on Monday in the lower to mid 80s. LONG TERM... (Monday Night through Sunday) No significant changes to the forecast, with showers and thunderstorms looking likely starting Monday Night and continuing for portions of the area into Wednesday. Scenario hasn`t changed much, with storms along the dryline across the far western Concho Valley early Monday evening blossoming on Monday Night across much of the area. This area of convection shifts into the eastern counties for Tuesday. Although the air mass behind the first round of storms will be less unstable and there may be a break in the precipitation for awhile, there is something to work with when the stronger cold front arrives late Tuesday Night and into the day on Wednesday. Thus, rain chances will continue for Wednesday and Wednesday Night. Upper level trough axis shifts across the area early Thursday and takes the precipitation chances with it as it exits. Cooler temperatures on Tuesday with lots of clouds and a rain cooled air mass across the area. Highs in the 70s. Even cooler behind the front on Thursday with highs in the 60s. && .PRELIMINARY POINT TEMPS/POPS... Abilene 65 83 60 71 / 20 30 70 50 San Angelo 64 84 61 76 / 20 30 60 40 Junction 64 84 64 77 / 20 20 50 60 Brownwood 65 81 62 73 / 20 20 60 60 Sweetwater 65 82 58 71 / 20 30 50 20 Ozona 64 82 61 76 / 20 20 60 40 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 99/99/04