Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/06/19

Area Forecast Discussion
National Weather Service Columbia SC
809 PM EDT Fri Apr 5 2019 .SYNOPSIS... Drier air will briefly build over the region tonight into Saturday with mainly afternoon showers on Saturday in the CSRA and southern Midlands. Another low pressure system will approach the region early next week resulting in numerous showers and thunderstorms at times, especially Monday. Dry and warm conditions expected Wednesday and Thursday behind the system. && .NEAR TERM /UNTIL 7 AM SATURDAY MORNING/... Satellite imagery shows some clearing in the CSRA and southern Midlands continuing to move northward. Expect the clearing to move through the entire forecast area over the next couple of hours...however low level moisture will remain plentiful overnight. Winds will be light and variable overnight and with dry air noted in model soundings conditions for fog/stratus will be favorable. As such expect clouds and fog to develop across the northern and central Midlands around midnight then expand southward into the southern Midlands and CSRA through the early morning hours. Areas of fog are expected over the entire forecast area by daybreak. Developing clouds and fog will limit radiational cooling with overnight lows generally in the low to mid 50s. && .SHORT TERM /7 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Saturday...Areas of fog expected around daybreak with dry air aloft and shallow low-level moisture. Nearly stationary front across south central Ga in the morning with surface Ridging across the Carolinas. The focus for showers early in the day mainly south of the CWA near the front. In the afternoon, the front appears to drift north near the CSRA and weak isentropic lift noted. Weak to moderate instability develops as low level moisture increases. Lift mainly across the southern or southeast CWA and there may be a weak short wave trough moving through around midday. Will continue isolated to scattered showers/thunderstorm in the CSRA and south Midlands mainly in the afternoon. Temperatures will be tricky, with considerable clouds in the south and some clearing north. Northeast low level flow and surface based inversion early, temperatures may be slow to rise. Large range in temperature guidance with nam much cooler than gfs 2m temps. Blended temp guidance has lowered from previous run so went cooler. Saturday night...Although moisture continues to increase across the area, think convection will be diurnal with upper ridge building in behind weak short wave trough. Any showers should be isolated and mainly near the frontal boundary. Temperature blend guidance accepted. Sunday and Sunday night...Increasing moisture across the area with resulting moderate instability across the area. Frontal boundary likely moves into the area with resulting convergence. Front should provide focus for scattered showers and thunderstorms. Coverage may be highest in the Piedmont with ridge centered offshore. Convection expected to be diurnally driven so pops diminishing after 00z. Temperatures well above normal with max temps near 80 and lows in the 60s. && .LONG TERM /MONDAY THROUGH FRIDAY/... Highly amplified upper trough and surface low will be off to the west to start off the week. ECMWF and GFS in good agreement through the longer term. Each show more of an open trough moving through the Deep South toward midweek. Low pressure system in the southern Plains early Monday will move east across the southern Mississippi Valley. Deep moisture from the Gulf of Mexico will spread northeast into the area. Expect precipitable water increase to around 1.6 inches in the afternoon. With deeper moisture across the area and resulting moderate instability, expect widespread showers and thunderstorms by afternoon. The models hint at convection in the evening possibly enhanced by increasing deep layer shear to the west. Scattered showers and thunderstorms Tuesday as upper level trough moves through the area and steep low to mid level lapse rates. Very cold temperatures at 500 mb around -20C. Drier conditions by Wednesday. Temperatures during this period will be above normal through this period with highs in the 70s and 80s and lows in the 50s to lower 60s. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... High confidence for restrictions developing after 06Z. Abundant low level moisture combined with dry air aloft, clearing skies early this evening and light to near calm winds will provide favorable conditions for fog/stratus to develop. HRRR and MOS guidance in agreement showing IFR stratus developing across the northern and central Midlands around 06z then expanding southward over central Georgia by 09z with MVFR/IFR cig/vsby. Have continued restrictions by 07z all terminals with both fog/stratus expected. Some weak isentropic lift will develop over the top of the stalled front to our south early Saturday and could result in isolated showers but chances to low to include in the forecast. Cig/Vsby restrictions should improve during the 14z-16z time frame, returning to VFR during the afternoon. AGS/DNL may be a bit delayed due to possible showers and their proximity to the front. Light and variable winds overnight becoming northeast around 5 knots after 14z then veering southeast during the afternoon. EXTENDED AVIATION OUTLOOK...There will be periods of MVFR or IFR conditions through Tuesday associated with a frontal system in the region. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
555 PM MDT Fri Apr 5 2019 .UPDATE... Issued at 547 PM MDT Fri Apr 5 2019 ...Please see latest 0Z aviation discussion && .SHORT TERM...(This evening through Saturday) Issued at 254 PM MDT Fri Apr 5 2019 A few light showers have begun to develop across southeast Wyoming under southwest flow from the approaching trough. Current visible imagery shows widespread cumulus coverage over the area, however low MLCAPE values around 200-500 J/kg have resulted in minor vertical development for the majority of these cells. Scattered showers will continue to develop late this afternoon and into this evening with isolated thunder possible, especially along the northern Nebraska Panhandle where instability is greatest. RAP soundings indicate an elevated Inverted-V profile with DCAPE of ~600 J/kg suggesting the potential for dry microbursts through early evening. Otherwise, main threats will be gusty winds up to 40 MPH and small hail with the strongest storms through 06Z Saturday. Warmer weather will continue on Saturday with highs in the 60s on the High Plains and in the upper 40s for the mountains. Scattered rain showers with a few rumbles of thunder are also possible across the region Saturday afternoon and evening with an approaching cold front. CAPE values look to be slightly higher on Saturday nearing 1000 J/kg, however shear will remain low and not support much organized convection. .LONG TERM...(Sunday through Thursday) Issued at 345 AM MDT Fri Apr 5 2019 Mild and dry conditions return Sunday and Monday under westerly flow aloft. Showers develop late Monday night along and west of a Douglas to Rawlins line, and spread east into southeast WY and northern NE Panhandle Tuesday. The next Pacific low pressure trough will be a progressive system, with widespread rain and higher elevation snow showers Tuesday night and Wednesday. Both the GFS and ECMWF are in better agreement with track of the upper low over southern WY and northern CO Wednesday morning, and southern NE and northern KS Wednesday afternoon. Surface low intensifies to 984mb over northeast CO by 12Z Wednesday, and 980mb along the NE/KS border by 18Z Wednesday. Despite being a progressive system, there is the potential for significant precipitation with up to an inch of liquid precipitation. Confidence is low to moderate on location and timing of snowfall. Snow levels may lower to 4500 feet Wednesday. Northerly winds may gust as high as 40 mph over the southeast WY plains and southern NE Panhandle Wednesday. Showers decrease in coverage Thursday. High temperatures Wednesday and Thursday will average 10 to 15 degrees below normal with highs in the mid 30s to mid 40s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 547 PM MDT Fri Apr 5 2019 The main concern across southeast Wyoming and the Nebraska panhandle is elevated showers above dry air at the surface. This could cause gusty and erratic winds near shower activity through this evening. Did not have enough confidence to put microbursts in the TAF, but it is possible. The weather will settle as we move into tonight and VFR conditions are expected for the remainder of the period. && .FIRE WEATHER... Issued at 240 AM MDT Fri Apr 5 2019 Fire weather concerns will remain low due to saturated soils and fuels. Warmer than normal temperatures will continue today with widely scattered showers and thunderstorms. This weekend will be breezy and mild, with scattered showers and isolated thunderstorms Saturday. Minimum relative humidities will average 25 to 30 percent through the weekend. Sunday and Monday will be mild and dry. Cooler temperatures, rain and snow showers will return Tuesday through Wednesday. && .HYDROLOGY... Issued at 254 PM MDT Fri Apr 5 2019 Despite warm conditions Friday, water will be slow to recede with more precipitation Friday afternoon through Saturday evening from scattered rain showers. Saturated soils will persist with remaining snow drifts melting and additional rainfall. The extended forecast indicates the potential for more rain and snow the middle of next week that will keep water levels high. For the latest information regarding flooding across Box Butte County and portions of Dawes County, please see the latest Areal Flood Advisory. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...CW SHORT TERM...MB LONG TERM...MAJ AVIATION...CW FIRE WEATHER...MAJ HYDROLOGY...MB
Area Forecast Discussion
National Weather Service Dodge City KS
605 PM CDT Fri Apr 5 2019 ...Updated aviation discussion... .SHORT TERM...(This afternoon through Saturday night) Issued at 1145 AM CDT Fri Apr 5 2019 Despite plenty of cirrus, temperatures were warming up rapidly through the 60s at midday, on the way to the 70s this afternoon. 12z NAM deepens a 999 mb surface leeside low east of Denver this afternoon, resulting in about 9 mb of mslp gradient across SW KS. S/SE wind gusts of 30-40 mph will be common through sunset, with gusts already near 40 mph at Garden City late this morning. Moisture advection will continue this afternoon with dewpoints holding in the lower 50s, contributing to modest CAPE and lifted indices through this evening. With no forcing available, forecast will remain dry through this evening. Rather vigorous shortwave over NW Mexico at midday will swing rapidly into SE New Mexico late tonight/early Saturday. As dynamic lift ahead of the shortwave arrives, with plenty of moisture available, showers and thunderstorms will develop across W TX and the TX panhandle after midnight. At least some of this activity will spread into the southern zones through Saturday morning, with 12z NAM being one of the most aggressive solutions bringing potentially heavy rain into SW KS. With other models also depicting measurable QPF, increased pop coverage, but further increases to the likely category may be needed especially Saturday morning. Clouds, moisture advection and elevated south winds will keep temperatures mild through sunrise Saturday, mainly in the lower 50s. Scattered showers and thunderstorms are expected to persist/favor the eastern zones throughout daylight Saturday as the shortwave works its way into Kansas. Moisture and instability will certainly be there to support further convective development through the day, with dewpoints in the lower 50s, CAPE of 1-2000 J/kg, and lifted indices to -5C. But the key to how much convection redevelops, and how strong it will be, will be tied to airmass recovery behind the morning rain/storms. For what it`s worth, long range HRRR shows convective redevelopment Saturday afternoon, in an area with healthy EHI values. On the other hand, shortwave timing does not look favorable, with most of the forcing leaving SW KS by peak heating, and subsidence resuming. Perhaps the best chance of strong/severe convection will be across the SE zones near Medicine Lodge Saturday afternoon, but again only if there is time to recover from widespread morning convective overturning. Pops are warranted for most zones through daylight Saturday, with SPC 5% wind/hail probabilities for all of SW KS. With clouds and precipitation, temperatures will held to the 60s for most locations. .LONG TERM...(Sunday through Friday) Issued at 235 PM CDT Fri Apr 5 2019 Sunday through Tuesday will feature an extended period of quiet, dry fantastic spring weather. Rising heights will support a warming trend each afternoon Sunday and Monday, through the 70s. Breezy north winds on Sunday, followed by much lighter winds on Monday. Tuesday will be the warmest day of the week. Flow aloft becomes zonal, as a powerful trough digs into the northern Great Basin. Associated lee cyclogenesis will begin Tuesday afternoon across NE Colorado, with ECMWF placing a 990 mb surface low east of Denver 7 pm Tuesday. A sharpening dryline will extend southward to West Texas, but all indications are the atmosphere will remain capped and quiet Tuesday. All locations will approach 80 degrees, with SW locales more than likely warming well into the 80s. Some of the warmest temperatures so far in 2019 expected on Tuesday. Models remain consistent, portraying an intense extratropical cyclone traversing Kansas and the central plains in the Wednesday time frame. 12z ECMWF and the model consensus forecasts an intense surface low to track across northern Kansas on Wednesday. This synoptic evolution would spread a significant snowstorm across Nebraska, keep any convection well to our east, and strongly dryslot SW KS. There is still plenty of time for a more southward trajectory to evolve in the models, but this outcome is most likely. High wind warning criteria is likely (40 mph sustained, gusting 58 mph) on Wednesday. Current solutions would argue for the strongest winds to be NWly post-frontal Wednesday afternoon. Model blend included a mention of rain/snow across the northern zones late Wednesday and Wednesday night for wraparound precipitation. These pops were retained, with the best chance of a wet snow accumulation along the I-70 corridor Wednesday night. Again, we will continue to be vigilant for a storm track change, as this storm will be intense and its impacts significant. Much colder air will pour in on Thursday, with afternoon temperatures struggling into the lower 50s. Current forecast from the blend is likely not cold enough, with ECMWF keeping us in the 40s. A hard freeze is now expected Friday morning, with a 1030 mb Canadian surface high settling over Kansas around sunrise. Again, going forecast of lows near freezing is likely not cold enough, with widespread 20s likely. ECMWF suggests lows of 22-24 are likely, with coldest locales in the teens. Early gardeners are reminded that the growing season has not yet begun. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 605 PM CDT Fri Apr 5 2019 An upper level disturbance will move northeast out of New Mexico this evening and across the central High Plains late tonight and Saturday. Chances for showers and isolated thunderstorms will increase across southwest and central Kansas later tonight into Saturday. The best chances for precipitation will be through late Saturday morning into the afternoon hours. Areal coverage of the precipitation does not look too widespread at this time so will keep prevailing VCSH in the terminals. There could be some potential for a period of MVFR cigs accompanying the showers. && .PRELIMINARY POINT TEMPS/POPS... DDC 54 68 49 71 / 40 60 30 10 GCK 52 69 47 69 / 20 30 20 10 EHA 46 71 46 70 / 30 10 10 10 LBL 51 71 49 70 / 50 30 20 10 HYS 56 68 49 72 / 10 50 50 10 P28 56 69 52 73 / 40 60 30 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Gerard
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1001 PM CDT Fri Apr 5 2019 .UPDATE... The 500 mb trough axis currently resides from near the Mexico/AZ/NM border and extends south into northern Mexico. Fairly robust deep convection is ongoing from around Midland to just southeast of Lubbock, with several severe thunderstorm warnings currently in effect. It has been a fairly quiet evening across our region, however. One lonely thunderstorm managed to develop near the Rio Grande west of Langtry and is currently tracking across northern portions of Val Verde County, and has not managed to come particularly close to reaching severe criteria. In fact, it continues to weaken as it heads northeast into a less favorable environment. Perusing the most recent high-resolution and convection allowing models, the 00z run of the 3 km NAM has backed off from developing the robust squall line in the early morning hours that the 18z run had developed. The HRRR continues to only develop some showers across the region through much of the overnight period before finally initiating some stronger storms out west across portions of the southern Edwards Plateau/Hill Country by mid morning. However, these are short-lived, and the HRRR continues to show the Austin and San Antonio metro areas largely missing out on showers and thunderstorms tomorrow altogether. The RAP, however, does develop fairly widespread convection across the region tomorrow morning and into the early afternoon hours, with respectable QPF totals (some areas above 2 inches), especially just west of Austin. In summary, there is still quite a bit of uncertainty in how this system is going to develop and evolve given the lack of a strong surface forcing mechanism like a cold front. Went ahead and made a few edits to the grids. Reduced PoPs for much of the region in the 1 AM to 7 AM time period, especially for areas along and east of I-35. It still looks looks like the best chances for widespread showers and thunderstorms for much of the region, especially the I-35 corridor and the Austin and San Antonio metro areas, will be from 7 AM to about 1 PM tomorrow. Only made slight edits to the PoP grids for this time frame, only trimming back PoPs for locations south and southwest of San Antonio. Strong to severe thunderstorms remain possible. SPC continues to keep our region under a slight risk for severe thunderstorms. Primary hazards would be strong winds and large hail, with a minimal tornado threat. && .PREV DISCUSSION... /ISSUED 705 PM CDT Fri Apr 5 2019/ AVIATION... The main concern this forecast period is convection at all sites. Model solutions vary widely, but many point toward the 17Z-22Z period on Saturday as the best chances for TSRA, except for earlier at KDRT, from 06Z-12Z. Look for MVFR-IFR CIGS after 05Z at KAUS/KSAT/KSSF, with MVFR CIGS at KDRT. Look for convection to end around 00Z Sunday, however expect additional -SHRA/-TSRA beyond the forecast period into the day on Sunday. PREV DISCUSSION... /ISSUED 329 PM CDT Fri Apr 5 2019/ SHORT TERM (Tonight through Saturday Night)... Visible satellite imagery this afternoon shows an agitated cumulus field developing across the Rio Grande Plains with ample heating allowing for temperatures to rise into the mid to upper 80s along the Rio Grande. As forcing for ascent continues to overspread the region ahead of a disturbance over southern Arizona/ northern Mexico later this afternoon and evening, high resolution guidance has remained consistent in an isolated thunderstorm or two developing across the higher terrain of Mexico and quickly propagating towards Val Verde County. Loss of heating will result in this first, initial round of activity quickly tapering off by mid-evening and expect the region to remain rain-free this evening. Deepening lee side troughing over the High Plains in response to the approach of the upper level disturbance is expected to result in a secondary round of thunderstorm development across West/West Central Texas into the Edwards Plateau and possibly as far south as the Rio Grande Plains overnight. The southern extent of development remains somewhat uncertain as the 12Z suite of model guidance remains varied on where the greatest lift will be realized across the western half of the state... and this is resulting in model solutions overnight indicating everything from thunderstorm activity remaining well north of the region to a broken line of thunderstorms propagating from the west/southwest towards Interstate 35 during the morning hours. What does appear to be certain at this point is that rain chances Saturday will be heavily dependent on what happens overnight. The approaching disturbance will also contribute to a strengthening 30-35 knot low level jet, which will help a stationary front along the Texas coast lift inland and result in another round of low clouds and possibly some drizzle along and east of Interstate 35 early Saturday morning. This initial boundary appears to lose definition as it lifts into Central Texas, but several convection allowing models are indicating that the West/West Central Texas thunderstorm activity may develop a strong enough cold pool to allow an outflow boundary to move into the Hill Country by Saturday morning. This would serve as a focus for continued development during the day Saturday as the main disturbance arrives. However, the past few runs of the HRRR do not develop an outflow boundary and keep all activity north of the region. Given the presence of good lift across the region, steep mid- level lapse rates, and plenty of shear, expect at least scattered thunderstorm development to occur across the region during the day Saturday. A lull in the activity will be possible by Saturday evening before a secondary round develops as the main disturbance lifts across the region. Based on the farther south trajectory, anticipate greatest rain chances south of the Interstate 35 corridor on Sunday morning. Thunderstorm threats tonight and Saturday appear to range from damaging wind, large hail, and frequent lightning. Steep lapse rates in excess of 8 C/km will not only contribute to this hail and wind threat, but high resolution guidance has been fairly consistent in indicating the presence of bowing line segments (raising concerns for the damaging wind threat). There has been an intermittent signal for potentially discrete cells developing ahead of these bowing segments east of Interstate 35, which may also be capable of an isolated tornado threat. This would be heavily contingent on surface destabilization during the day across these areas... which the presence of low clouds/drizzle may complicate. Cannot rule out the threat for locally heavy rain given the instability present, but precipitable water values less than 1.5 inches and developing drought conditions across portions of the region will help mitigate against any widespread flood threat. LONG TERM (Sunday through Friday)... The disturbance begins to close off over the ArkLaTex on Sunday with associated north/northwest flow pushing Sunday morning rain chances off to the east by Sunday afternoon. This will help western areas dry out and heat up into the low to mid 80s by Sunday afternoon with slightly cooler highs in the mid 70s to low 80s across the east. Steep lapse rates and long, skinny CAPE profiles indicating water- loading of updrafts will contribute to a lingering damaging wind threat across the Coastal Plains Sunday morning along with the threat for locally heavy rain. A few wraparound showers may be possible across portions of the Brazos Valley/Central Texas into the Coastal Plains Sunday night into Monday morning as the upper low ejects towards the northeast, but dry conditions are expected through the workweek. Shortwave ridging building in behind this system will result in temperatures rising into the mid 80s to low 90s across the central and eastern portions of the region mid-week with the Rio Grande possibly seeing the first 100 degree day of the year on Wednesday. A fast-moving shortwave trough traversing the Central Plains Wednesday into early Thursday will send a dry cold front across the state on Thursday. Somewhat cooler high temperatures in the low 80s to low 90s are expected as the front passes Thursday with highs finishing the work week in the low 70s to low 80s as additional cooler air filters into the region. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 66 79 64 81 59 / 30 70 40 50 10 Austin Bergstrom Intl Airport 66 79 64 81 59 / 30 70 40 50 10 New Braunfels Muni Airport 65 80 63 82 59 / 30 60 40 60 10 Burnet Muni Airport 64 78 62 81 57 / 30 80 30 40 10 Del Rio Intl Airport 65 87 61 89 59 / 50 30 10 - - Georgetown Muni Airport 66 78 63 80 57 / 30 80 50 50 10 Hondo Muni Airport 67 84 62 86 58 / 40 70 30 50 - San Marcos Muni Airport 65 80 64 81 60 / 30 70 40 60 10 La Grange - Fayette Regional 69 81 66 78 60 / 20 50 50 70 10 San Antonio Intl Airport 66 81 64 82 59 / 30 70 30 50 - Stinson Muni Airport 67 83 64 82 60 / 30 60 30 60 - && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Aviation...Zeitler Short-Term/Long-Term...BMW
Area Forecast Discussion
National Weather Service Grand Rapids MI
700 PM EDT Fri Apr 5 2019 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 320 PM EDT Fri Apr 5 2019 - Fog, locally dense, is possible overnight lasting into the first few daylight hours of Saturday. - The warmest weekend of 2019 so far is on tap with increasing precipitation chances Sunday afternoon/evening. No severe weather is expected at this time. - An active pattern is shaping up from the middle of next week onward, with wintry weather not out of question. && .DISCUSSION...(This evening through next Friday) Issued at 320 PM EDT Fri Apr 5 2019 Cloud cover was stubborn to go away this morning but clearing is finally been observed across large chunks of the area, leading to soaring temperatures into the upper 40s and lower 50s. As a high pressure system slides over the Great Lakes tonight, fog development (locally dense) is possible lasting through mid- morning Saturday. We`ll let the evening crew determine whether any fog headlines are needed as areal extent is uncertain, but the clearing skies as of this writing suggest greater potential for widespread fog tonight. Temperatures overnight should range from around freezing along the US-10 corridor to around 40 near I- 94. As upper-level ridging becomes established over the Great Lakes on Saturday, low-level south/southwesterly flow will allow for spring- like temperatures in the low to mid 60s area wide. Sunday looks even warmer with highs climbing into the upper 60s, making way for the warmest weekend of 2019 so far. Unfortunately it may be hard to see the sun, especially Sunday, as a broad and somewhat disorganized upper-level trough approaches from the southwest. While dew points and PWATs are progged to climb north of 50 degrees/1" Sunday afternoon, the general disorganized nature to the trough (muddled immensely by expected widespread convective activity to our south) makes identifying clear sources of lift Sunday afternoon/evening hard to discern. Maybe an MCV-like feature originating from activity in the Plains Saturday night will swing our way on Sunday? All the while forecast thermal and kinematic profiles suggest little potential for anything organized in our neck of the woods. But for now there`s still enough to warrant increased precipitation chances, including perhaps a weak thunderstorm or two, Sunday afternoon/evening. Forecast deterministic guidance suggests a clipper system will swing through the Great Lakes Tuesday dragging along a cold front, effectively ending our warm stretch. If the front comes through right at "peak heating" Tuesday afternoon, a band of showers or even a weak thunderstorm is possible though the chance for severe weather again appears pretty low. The bigger forecast concern is the potential for a period of active weather toward the latter portion of next week (and beyond?) as a strong 180+ kt Pacific jet develops into deep troughing across the western U.S., placing the Great Lakes at the end of what may end up being a fire hose of systems. The first will take aim at the Great Lakes around the Thursday/Friday with the 12Z suite of deterministic models sharing remarkable (and likely coincidental) agreement in supplying a swath of heavy snow right through central Lower Michigan. Yet the ensemble solution spaces are still vast including solutions in which Lower Michigan gets missed entirely, so an April snowstorm is definitely not set in stone. Stay tuned. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 700 PM EDT Fri Apr 5 2019 It would seem there is a good chance (not 100%) that dense fog will develop at most of the TAF sites overnight. Most of the area had around a tenth of an inch of rain last night and with the evaporation rate (measured by some meso-nets) around 0.05" today, there is enough moisture remains from the precipitation last night, assuming skies are mostly clear to develop dense fog. Winds are light with the surface high near by. Also more moist air is being pushed into cooler and drier air just above the surface overnight. Model sounding from the HRRR / NAM12 show the classic fog look with shallow saturation near the ground with temps/ dew points increase around 3c in the first 500 ft above the ground. The fog should lift to a low cloud deck by mid to late morning then clear from south to north as dry air moves up from the south as the surface high continues to move to the east. && .MARINE... Issued at 320 PM EDT Fri Apr 5 2019 Winds and waves are expected to remain relatively calm (at or below 15 kts and 3 ft, respectively) through early next week. Fog development is possible this weekend, some of which may be dense with westward extent. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ SYNOPSIS...Borchardt DISCUSSION...Borchardt AVIATION...WDM MARINE...Borchardt
Area Forecast Discussion
National Weather Service Lincoln IL
820 PM CDT Fri Apr 5 2019 .UPDATE... Issued at 820 PM CDT Fri Apr 5 2019 Primary question will be with any kind of clearing overnight. Latest GOES-16 nighttime microphysics combo showing the western edge of the cloud deck from near the Quad Cities to south of Quincy, but the clearing appears to be hitting a brick wall. Evening sounding from our office shows the clouds to be about 2,000 feet thick, with an inversion at 850 mb at the top. RAP and NAM try to make some slow progress with moving this cloud deck east, but pessimism may be the way to go in this case. Have maintained the mostly cloudy forecast overall, but showed a slight short improvement west of the Illinois River for awhile late this evening. Hourly temperatures needed some adjustments over the next few hours, as they were running too warm. However, with the clouds hanging around, a significant dropoff is not anticipated, and went with lows fairly close to the earlier projections. && .SHORT TERM...(This evening through Saturday) ISSUED AT 345 PM CDT Fri Apr 5 2019 Broken to overcast stratus cloud deck lingered over much of IL especially south of I-88 at mid afternoon. Abundant low level moisture/wet ground, along with a restrengthening low level inversion and weak wind flow will allow more lower stratus and fog to set in especially overnight into mid morning Saturday. Lows overnight in the mid to upper 40s in central IL, with southeast IL near 50F. Skies to become partly sunny during Saturday afternoon, with low clouds lingering longer in eastern IL. SE winds increase to 8-15 mph by Saturday afternoon, with milder highs in the upper 60s to near 70F. .LONG TERM...(Saturday night through Friday) ISSUED AT 345 PM CDT Fri Apr 5 2019 The 12Z forecast models continue to trend slower with arrival of next wx system ejecting from the southern Rockies, with surface low near the IA/MO border by dawn Sunday. Saturday evening should continue dry, with chances of showers and isolated thunderstorms spreading ne over CWA after midnight Sat night. Mild lows Saturday night in the mid 50s. Good chance of showers and some thunderstorms on Sunday and mild highs in the lower 70s with breezy sw winds. SPC day3 outlook has slight risk of severe storms in southeast IL later Sunday afternoon into mid Sunday evening with marginal risk of severe as far nw as the IL river. Though latest models are not quite as strong with the instability and bulk shear parameters. Chance of showers and isolated thunderstorms lingers Sunday evening, and over areas from I-55 se overnight Sunday night. A surface low and upper level trof over the lower MS river valley Monday could bring chances of showers into southeast IL yet on Monday, while thunderstorms chances mainly closer to the Ohio river on Monday. Mild temperatures in the lower 70s for highs Monday across CWA. Dry wx expected across area Monday night thru Tuesday evening with slightly cooler highs in the upper 60s north of I-72 and lower 70s again from I-72 south. A much stronger surface low pressure system ejects from the central Rockies into KS during Wed with a warm front extending eastward over the mid MS river valley. Increasing chances of rain showers mainly along and north of I-72 overnight Tue night into Wed. More of a north to south temp gradient on Wed with highs mid to upper 50s northern CWA and upper 60s to near 70F in southeast IL. 993 mb surface low pressure tracks into St Louis area by midnight Wed night and travels near I-70 into west central IN by dawn Thu. Good chance of showers and some thunderstorms over area Wed night and lingering chances of showers Thu. Stronger winds on Thu with cooler temps, highs Thu range from low to mid 50s northern CWA and low to mid 60s in southeast IL. Some light rain showers linger Thu night and could mix with light snow showers overnight Thu night into Fri morning. Highs Fri in the upper 40s and lower 50s, mildest in southeast IL. Lows by next Friday night to reach lower 30s over much of area especially from I-70 north. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 631 PM CDT Fri Apr 5 2019 Challenging forecast for this TAF set. Fairly widespread MVFR cloud deck exists across central Illinois at 23Z, with ceilings about to lower near the Indiana border. Some clearing is edging into extreme western Illinois, but there is some question on how much this is going to progress eastward. Any clearing would likely result in a quick formation of very low clouds and fog. Went the pessimistic route for now, and kept MVFR going until about 09Z, with a few hours of IFR. Clouds may struggle again to scatter out on Saturday, but will show some improvement by 18Z. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Geelhart SHORT TERM...07 LONG TERM...07 AVIATION...Geelhart
Area Forecast Discussion
National Weather Service Lubbock TX
652 PM CDT Fri Apr 5 2019 .AVIATION... Scattered TSRA just SW-W of LBB will continue developing and moving north through early evening, before a more considerable round of TS arrives in the 9-11 PM time frame. Some TS will be severe with downbursts and hail. After TS affects all terminals tonight, MVFR to perhaps IFR ceilings are likely at all sites before drier SW winds overspread the Caprock toward midday. At CDS, there is a slim chance for additional TS tomorrow afternoon near a dryline, but prospects for this are too low at this time. && .PREV DISCUSSION... /issued 243 PM CDT Fri Apr 5 2019/ DISCUSSION... The main weather impacts will be the potential for severe thunderstorms this evening into overnight and strong winds on Wednesday. The shortwave trough responsible for tonight`s weather is currently over northwestern Mexico and will quickly move east. Ahead of this trough cloud coverage has increased and southerly winds are brining up dewpoints in the mid 40s to mid 50s this afternoon. By this evening upper level flow is very divergent and 850mb winds will increase around 00Z with surface convergence over the South Plains. Hi-res models have backed off some on early showers but have two main rounds later. Both the HRRR and RAP have storms initiating southwest of Lubbock around 00-01Z then moving northeast in a bowing line. Then another round starts around 08Z further south and moves northeast. With good instability and minimal CIN, expect storms to become strong with hail up to 2 inches and winds to 70 mph possible. As 850mb winds increase after 00Z, shear also increases with longer and more curved hodographs so tornadoes will also be a possibility. Storms will continue through the night and may not clear the eastern counties until after 10-11Z. Have also increased PoPs in the Rolling Plains Saturday morning to account for any lingering rain. The upper level trough will continue to move east through the weekend. A weak cold front will move through on Sunday morning dropping highs a few degrees. Upper level ridging will build early next week leading to above normal temperatures and highs will reach the upper 80s to low 90s by Tuesday. As the next trough approaches on Wednesday the pressure gradient will tighten significantly resulting in a windy day. Have gone on the higher end of guidance with winds 25-30 kts but did not go as highs as the MOS guidance of 45kts. Depending on how much rain we get tonight, above normal temps and high winds may lead to fire weather concerns on Wednesday. && .LUB WATCHES/WARNINGS/ADVISORIES... None. && $$ 93
Area Forecast Discussion
National Weather Service Blacksburg VA
1011 PM EDT Fri Apr 5 2019 .SYNOPSIS... Low pressure over the Mississippi Valley will move east and offshore by Saturday followed by weak high pressure. A complex low pressure system over the Plains Saturday will track into New England and will push a cold front across the Mid Atlantic region on Tuesday. Yet another low pressure system moves from the central United States into the east by the end of the week. && .NEAR TERM /THROUGH SATURDAY/... As of 1011 PM EDT Friday... No major changes to the going forecast at this point and have only accounted for current observations into the going forecast with this update. In-situ wedge has built southward into the Carolinas leading to lots of overcast skies and reflected in the GOESEast Nighttime Microphysics RGB composite imagery. Wedge will remain with us through the remainder of the overnight, though some erosion of overcast cloud cover is anticipated toward the pre-dawn hours across the Mountain Empire. Periods of mist or light ground fog to this point haven`t been as prevalent in the presence of modest northeast/east surface winds. However winds are expected to lighten some and this may increase coverage of foggy areas into the overnight as temperature/dewpoint spreads are quite narrow. Don`t think we`ll see dense fog from this but based on recent HRRR and NBM visibility guidance, the potential for SPS- worthy fog mention isn`t out of the question, especially in the New River Valley area and adjacent portions of I-81. No changes to low temperatures which will only fall a few degrees given prevalence of cloud cover and limited to weak warm low-level thermal advection. As of 145 PM EDT Friday... Rainfall winding down from east to west across the CWA early this afternoon, with a few lingering showers across the piedmont over the next few hours before ending completely. Rainfall totals up to 18z (2 PM) generally in the 0.25 to 0.75 inch range with some higher amounts approaching 1.00 inch or more over parts of SW VA. Both Dual-Pol and Legacy radar estimates are higher over parts of New River Valley with 2+ inches in some areas but not corroborated by any rain gages and possibly due to bright-band effects. Either way, no hydrologic impact other than mostly welcome rain. Skies will remain cloudy this afternoon and evening for the most part with patchy drizzle early and some fog possible overnight and temps holding mainly in the 40s. Some in-situ wedging will remain into Saturday morning as the weak surface low off the NC coast slowly drifts eastward into the western Atlantic which may delay clearing until late morning or even early afternoon depending on how strong it is. As a more zonal westerly flow takes over will see generally clearing skies later in the day with a noticeable warmup by mid- to late afternoon, some 15-20F higher than today. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 230 PM EST Friday... Saturday night into Sunday an upper level shortwave ridge will build over the area. Closer to the surface, southerly flow will start to increase on the west side of a ridge of high pressure that will be situated along the east coast of the U.S. and on the east side of an upper level shortwave trough across the center of the country. The result will be the advection of the low level moisture into the area that will bank-up against the higher terrain along the crest of the Blue Ridge. Look for some patchy light rain in this area Saturday night. On Sunday, a warm front will cross the area early on Sunday and be situated north of the area by Sunday night. As Sunday progresses, the lower atmosphere will become slightly unstable in the west, and allow for the potential for some isolated to scattered showers and storms. Sunday night into Monday night, the central U.S. upper low/trough will make slow progression towards the area. This will keep showers in the forecast during the period with isolated to scattered thunderstorm Monday from mid-day through the early evening. Some locally heavy rain is possible during this time period. Temperatures will trend milder during this portion of the forecast. By Monday into Monday night temperatures will average around ten degrees above normal. Forecast confidence during this portion of the forecast is moderate to high. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 1230 PM EST Friday... On Tuesday, a closed upper low will be poised to head eastward from over the Tennessee Valley to the coast of the Carolinas, thus bringing its associated cold front into and through our region. In advance of this system a generous fetch of Gulf of Mexico moisture will be advecting into the area on increase 850 mb winds. While showers look very probable across the area, isolated thunderstorms also cannot be ruled out. Forecast afternoon surface based CAPE values are expected to be in neighborhood of 1000 - 2000 J/Kg just as the associated front is crossing the area. High pressure is expected to build into the area in the wake of the Tuesday-system. This is expected to bring dry weather to the area for the latter half of Tuesday night, Wednesday, Wednesday night, and Thursday morning. Tuesday evening parts of the area still may have some lingering showers associated with the departing cold front, especially the southeastern sections of the forecast area. Thursday afternoon through Friday model guidance becomes a bit more variable in terms of timing and positioning of the main synoptic features. What is consistent among the solutions is a trend for the center of the next upper level trough/low to remain close to the U.S./Canadian border. The biggest question is not whether it will have an associated cold front or not, or if it will cross our area, but more of timing of this feature and sensible weather influence on our area. A consensus forecast offers late Thursday night into early Friday as the time frame with isolated to scattered coverage of showers, especially across western and northern sections of the forecast area. Temperatures during the Tuesday through Thursday portion of the forecast are expected to be around ten to fifteen degrees above normal. By Friday, readings will be closer to normal, or about five degrees above normal. Forecast confidence during the Tuesday through Thursday timeframe is moderate with low to moderate confidence on Friday. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... As of 731 PM EDT Friday... Low clouds will linger tonight into Saturday morning with areas of fog and patchy drizzle or light rain. Widespread IFR/LIFR will continue tonight into Saturday. Gradually improving flight conditions on Saturday as the weak low off the coast departs and weak cool air wedge dissipates. Winds will remain light tonight into Saturday. Be prepared for mountain obscurations overnight with the low clouds. Medium confidence in ceilings,visibilities and winds during the taf period. EXTENDED AVIATION DISCUSSION... MVFR/IFR conditions are possible with scattered showers and isolated thunderstorms Sunday through Tuesday. Drier weather is expected Wednesday into Wednesday night. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...AMS NEAR TERM...AL/KK/PC SHORT TERM...DS LONG TERM...DS AVIATION...KK/PC
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Saturday) Issued at 338 PM CDT Fri Apr 5 2019 20Z water vapor imagery shows an upper trough over the southwestern U.S. with a shortwave over the Pacific Northwest lifting into British Columbia. At the surface, an area of low pressure was slowly deepening along the lee of the central Rockies. This has kept a southerly wind over the forecast area with dewpoints steadily rising into the lower 50s. For tonight the main question is whether there will be any showers ahead of the main upper trough. Various solutions develop some light QPF across north central KS. But a closer look at the forecast soundings shows some mid level dry air that would need to be overcome. With the general consensus among models for the main surge of moisture to occur Saturday afternoon, think chances for measurable precip are only around 10 percent across north central KS tonight. SO will maintain a dry forecast. Stronger mixing tonight is expected to preclude any fog formation. Although the NAM insists on some saturation in the boundary layer. If the NAM proves correct, think there may be some stratus develop. But with the GFS and RAP having a hard time saturating the boundary layer, do not have much confidence in the NAM solution and think mid and high clouds will be predominate. For Saturday, precip chances should be on the increase through the afternoon and into the evening. Confidence in widespread precipitation is waning as models have trended towards a ill-defined wave lifting across the area. Nevertheless there should be plenty of moisture ahead of the wave with some modest instability of around 1000 J/kg so have kept POPs in the likely category. Risk for severe storms appears to be pretty conditional as lapse rates and deep layer shear are fairly marginal. Hodographs show weaker mid level winds cause an inflection in the hodograph implying storms may have a difficult time remaining discrete. So while an isolated storm with hail can`t be ruled out, the environment doesn`t look favorable for a lot of severe weather. .LONG TERM...(Saturday night through Friday) Issued at 338 PM CDT Fri Apr 5 2019 Showers and storms are expected to lift out of the area late Saturday night with the upper trough axis moving into IA. There could be some redevelopment on Sunday as a weak frontal boundary moves through the area. Again there could be some modest instability out ahead of the boundary. But dynamics look to be disorganized with possibly some frontogenesis along the boundary being the main driver of redevelopment. There is not a lot of cold air progged to move in behind the boundary, so highs on Sunday have trended warmer. Much if not all of the forcing for vertical motion looks to be east of the area by Sunday evening. So the forecast is for dry weather Sunday night through Tuesday night before the next upper trough moves into the plains. Have trended temps warmer for Monday with models showing good low level warm air advection and a downslope component to the surface wind. A weak backdoor front may still try to move into the forecast area on Tuesday. Still looks like highs could reach the 70s. But this will be dependent on how strong the boundary turns out to be. There is still a fair amount of spread in the models with the system for Wednesday and Thursday. Because of this have stayed pretty close the the consensus blend. In general there appears to be a trend for a more southern track to the low pressure system. This could allow from some snow to mix in with the rain across northern KS Thursday morning. But models tend to show the heavier QPF lifting out of the area as temps fall into the 30s. Have trended temps cooler for Thursday and Friday as the ECMWF and GFS develop some reasonable cold air advection behind the system. With that lows are forecast to be in the 30s with highs in the 50s. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 636 PM CDT Fri Apr 5 2019 Expect VFR conditions for the next 24 hours. Most numerical models keep visibilities above 7 miles through the early morning hours of Saturday. The NAM and WRF-ARW did show patchy fog developing at the KTOP and KFOE terminals, though my thoughts are that the nocturnal boundary layer may not decouple fully due to a low- level jet increasing to 35-40 KTS at 1200 feet above the surface after 6Z SAT. There will be 30-35 KTS of low-level wind shear from the surface to 1500 feet at the terminals from 6Z SAT-14Z SAT. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...Wolters AVIATION...Gargan