Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/18/19

Area Forecast Discussion
National Weather Service La Crosse WI
615 PM CDT Wed Apr 17 2019 .SHORT TERM...(This evening through Thursday) Issued at 254 PM CDT Wed Apr 17 2019 There remains a small threat for a strong to severe storm early this evening across portions of northeast Iowa into southwest Wisconsin. The area of low pressure is still expected to track northeast into northern Wisconsin this evening. This should allow the warm sector to briefly advance north into parts of the region with dew points quickly climbing into the upper 50s to lower 60s creating surface based CAPEs of 500 to 1000 J/kg. Ample 0-3km shear, up to 40 knots, will reside over the warm sector with about 20 to 25 knots of this in the 0-1 km layer. If any storms can become rooted in the boundary layer, they could produce a brief tornado. However, forecast soundings from several runs of the RAP suggest there is a very short 1 to 2 hour window where the cap might erode long enough for the storms to become surface based. Even if they do, the CAPE profile still does not all that favorable being very skinny and suggesting the updrafts may not be strong enough to survive for very long. Overall, this continues to be a very marginal severe weather threat but one that will have to monitored until the cold front moves through early this evening. Once the low goes by the area, low level cyclonic flow will set up for Thursday. This combined with the main upper level trough could be enough to generate some shower across parts of the region and have kept in some small rain chances for that. .LONG TERM...(Thursday night through Wednesday) Issued at 254 PM CDT Wed Apr 17 2019 The 17.12z GFS/ECMWF/NAM are in decent agreement in digging upper level trough over the Ohio River Valley Thursday night into Friday and closes off upper level low over the southeast United States Friday night into Saturday. The eastern part of the forecast area remains on the western periphery of the upper level trough and produces a small chance of rain showers across southwest/central Wisconsin Thursday night. Then...upper level ridge builds into the Northern Plains States/Upper Midwest Friday into Saturday. Subsidence underneath ridge will provide dry weather across the forecast area. Cooler temperatures filter into the Upper Midwest briefly behind upper level trough with low temperatures falling into the 30s Thursday night across the forecast area. Warmer air advects into the forecast area Friday/Saturday...with the 17.12z GFS/NAM/ECMWF showing plus 12 to plus 17 degrees celsius at 925mb by 00z Sunday. High temperatures should climb into the 60s and possibly into the lower 70s in a few locations Saturday. Main forecast concerns Saturday night into Wednesday are precipitation chances through the period. The 17.12z GFS/ECMWF/GEM suggest overall pattern becomes west to east zonal flow over the northern tier United States. The deterministic models are not in agreement in the strength of each piece of energy embedded in the west to east zonal flow aloft. This will have impacts on timing of precipitation chances and how widespread the showers or rain will be across the area through the period. Temperatures through the period will be near normal...with highs climbing into the middle 50s to middle 60s. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 615 PM CDT Wed Apr 17 2019 Cigs: low saturation slated to hold fast across the region through most of THU with satellite imagery showing expansive cloud shield through the northern plains. Should see minor improvement in heights through the TAF period, but probably not VFR until it scatters out - more likely Thu evening. WX/vsby: shra/ts likely cleared east of KRST around 00z, lingering at KLSE til 02-03z. Not anticipating any br/fg post the showers as winds pick up, sfc Tds start to dry out with cold front pushing east. Winds: direction will quickly swing northwest/north by 00-02z with passage of a cold front. Periodic gusts through the period. Should see some slackening by Thu evening with approach of weak high pressure. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...DTJ LONG TERM...DTJ AVIATION...Rieck
Area Forecast Discussion
National Weather Service Bismarck ND
943 PM CDT Wed Apr 17 2019 .UPDATE... Issued at 942 PM CDT Wed Apr 17 2019 Rain showers were decreasing in intensity and areal coverage over the past hour across eastern Montana and the western Dakotas. Isolated thundershowers are possible for another hour or so, with MU CAPE still at around 250-500 J/kg over western North Dakota. Farther east, the area of rain showers had shifted moreso into the eastern third of the state, with only lingering light showers for the Turtle Mountains and James Valley areas after midnight. The other concern is that some of the short term high res models are indicating fog formation - especially for central North Dakota. Makes sense with the widespread rain and relatively light winds in central ND, while farther west we have had the warmer/drier air move in with westerly winds. Thus have added a mention of areas of fog tonight over most of central ND. UPDATE Issued at 644 PM CDT Wed Apr 17 2019 Minor changes to keep at least a small chance of of showers and isolated thunderstorms over the western third of the state through the evening. A line of showers with isolated thunderstorms were in western North Dakota, mainly from Williston and Watford City south to Dickinson/Hettinger areas. Behind or associated with this line of showers, there could be brief periods of gusty winds over 30 mph. Otherwise, the area of showers in central North Dakota continued to move east. Regarding cloud cover, the north-south clearing/scattering line between overcast low clouds in central North Dakota and scattered clouds to the west was approaching the Minot/Bismarck area. Expect the eastern part of central North Dakota - mainly from the Turtle Mountains to the James Valley - to remain cloudy tonight. There may be a chance for fog formation over mainly central North Dakota - on the western edge of the overcast clouds - especially since the widespread rains have resulted in moist soil conditions. Not yet confident of this...depending on whether the light west winds keep the lower atmosphere mixed. Will monitor trends for later updates. && .SHORT TERM...(This evening through Thursday) Issued at 243 PM CDT Wed Apr 17 2019 Latest water vapor imagery shows an upper level shortwave trough stretching from southeastern into western North Dakota, and progressing east with time. Deformation zone evident on radar imagery across north central North Dakota which will allow for precipitation to continue until 00z Thursday. Across the west, visible imagery shows subsidence behind the trough with partial clearing. Glasgow radar shows isolated showers/thunderstorms within their vicinity now, and this is a sign of the instability field that will propagate into western North Dakota this afternoon and evening. As surface heating begins in the west, unstable conditions develop in the lower levels, with RAP BUFKIT soundings showing an uncapped environment. Decent low to mid level lapse rates in place, surface based CAPE up to 400 J/Kg, but deep layer shear is weak at 20kt. Given a nearly unidirectional wind sounding with northwest flow aloft, concur with the CAM`s that a weak line of showers/thunderstorms will initiate in the west and scoot east this evening. As the indicated, the strongest storms may produce small hail. This idea still looks good. Expect scattered showers and isolated thunderstorms through the evening as a 500mb cold pocket remains overhead. Showers dwindle overnight, however a few light showers may continue past midnight per latest high resolution models. This seems reasonable as two more shortwaves roll through western North Dakota later tonight, then across central ND Thursday. This sets the stage for a continue chance of showers and possible thunderstorms Thursday. Severe weather is not expected. Warm air advection aloft across the west Thursday will inhibit the threat for convection, with the cold pocket getting shunted off to the east in the afternoon. Lows tonight will be in the 30s, with highs in the 50s Thursday afternoon. .LONG TERM...(Thursday night through Wednesday) Issued at 243 PM CDT Wed Apr 17 2019 A transitory upper ridge takes control Friday with strong low level warm air advection. Highs will reach the mid 60s east central to mid 70s west. Westerly/downsloping winds 15 to 30 mph will ensue along with minimum relative humidities between 15 and 20 percent especially across southwest and south central North Dakota. This may lead to potential fire weather concerns and will continue to monitor. Otherwise, after a warm and dry day Friday, a cold front will sweep through Friday night into Saturday morning. Expect a chance of showers and possible thunderstorms with this cold front. Cooler air will gradually filter in from west to east Saturday through Sunday. Dry Sunday with highs in the 50s. Monday through Wednesday looks mostly dry as well with highs in the 60s. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 644 PM CDT Wed Apr 17 2019 Scattered showers and isolated thunderstorms possible at KISN and KDIK until around 03z. Otherwise VFR for these sites overnight and Thursday. Scattered showers and overcast MVFR cigs at KBIS/KMOT should become VFR by around 03z, then late tonight after 09z MVFR cigs to return with possible MVFR vsbys in light fog. Becoming VFR after 14z/15z Thursday. KJMS to remain overcast through tonight. MVFR with some IFR stratus around until 03z with scattered rain showers. MVFR/VFR cigs after 03z, with improving conditions after 13z Thursday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...JV SHORT TERM...KS LONG TERM...KS AVIATION...JV
National Weather Service Cleveland OH
1011 PM EDT Wed Apr 17 2019 .SYNOPSIS... A warm front will lift north of the area overnight as low pressure tracks northeast across the Upper Midwest. The low will continue east across the Upper Great Lakes on Thursday while another area of low pressure develops over the Lower Mississippi Valley. This low will move northeast along the stalled frontal boundary, pulling a cold front south behind it and bringing unsettled weather through the first half of the weekend. && .NEAR TERM /THROUGH THURSDAY NIGHT/... Warm advection and favorable mid/low level jet dynamics have been enough to generate showers and thunderstorms across NW Ohio. A few of these thunderstorms were able to produce some pea size hail. Still uncertainty on how far east these showers/thunderstorms will make it with dry air in the middle levels of the atmosphere indicted by the rapid refresh model suite. So at this point will buy into this scenario and have the showers/thunderstorms struggle to make much past a Cleveland to Millersburg line. Previous Discussion... A frontal boundary remains stalled across the area extending from near Findlay to just south of Cleveland. Low pressure over Iowa this afternoon will continue northeast tonight, pulling a warm front north of the area with some locations still yet to hit the high temperature for the day. Mild conditions expected overnight, ranging from the mid 50s to near 60 degrees with varying degrees of mid and high level cloud. Regional radars are picking up on a few showers extending from Lake Michigan to southwest Ohio but have not seen any reports of this actually reaching the ground given dry air in the low levels. The HRRR shows some expansion of these showers as the low level jet develops and moves northeast into Michigan but model soundings remain dry enough that did not include in the forecast at this time. Low pressure will move to northern lower Michigan by morning ahead of the upper trough deepening over the northern Plains. A good surge of moisture arrives in northwest Ohio by morning with showers expanding, mainly west of I-71. A minimal amount of elevated instability is present and could see a few thunderstorms develop by morning. Eastward progress of the rain will be slow, not expanding to northeast Ohio until Thursday night when the cold front arrives. Areas east of the rain in the warm sector will likely see gusty winds develop by midday Thursday with a strong wind field aloft. Mixing depth only expected to reach 2-3K feet but could tap into gusts of 35-40 knots. Later shifts will need to evaluate need for a wind advisory for portions of north central Ohio. Too much expansion of clouds or showers may limit the winds but expecting some partial clearing in the warm sector during the afternoon. Temperatures in the east will be well above normal in the mid 70s. Plenty of room for error in temperatures again on Thursday night depending on the forward progress of the front. Current forecast thinking is the front will be most of the way through the area by late Thursday night with northerly winds dropping temperatures back into the mid 40s to mid 50s. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... The short term begins Friday with low pressure centered over Ohio. Will have likely to categorical pops for the area through the day. Main concern will be the threat of thunder east as unstable air gets wrapped into the east side of the system during the afternoon. For now will have a chance of thunder in the morning and chance to likely thunder for the afternoon. Will continue with categorical pops for rain most areas Friday night as the low pulls northeast but another wave develops and moves north across western PA. No big change Saturday. Sunday another cold front will approach from the northwest. Will have chance pops for showers for now. Highs in the 50s Friday and Saturday and in the 60s Sunday. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Monday and Tuesday high pressure will be to the north of the lakes extending south into northern Ohio. Models differ a bit but there will likely be a front east to west across northern Ohio with moisture streaming east along the boundary. Will have chance pops sunday night through Tuesday and again on Wednesday with the region likely the interface between mild, unstable air from the south and cool stable air from the north. Will have thunder mentioned during the days Monday and Tuesday and then everywhere Wednesday. Highs in the 60s but expect cooler along the lakeshore especially east of Cleveland. && .AVIATION /00Z Thursday THROUGH Monday/... Added some thunder to NW Ohio as it developed just before 00Z. VFR conditions are expected across the region through the night. A few higher based showers/sprinkles will move eastward across the area this evening but will likely only produce trace amounts of rain. These should dissipate as they drift eastward into slightly drier air at the middle levels of the atmosphere. The better chance for showers, maybe a thunderstorm, will be across NW OH around sunrise. These showers/thunderstorms will slowly drift eastward through the day on Thursday. Most of these will not reach the OH/PA border until after dark Thursday evening. MVFR conditions will be possible with the heaviest showers/thunderstorms. Winds will be light near the warm front this evening but as it lifts further northward the southerly winds will reach up to the lakeshore. Downsloping winds near KERI will become gusty after 04Z. South to southwest winds after sunrise should be in the 15 to 20 knot range with gusts 25 to 35 knots common. The strongest gusts may approach 40 knots across the west if we see a period of sunshine. OUTLOOK...Non-VFR in showers and possible thunderstorms on Thursday night into Friday. Showers under an upper level low may keep conditions non-VFR across the region at times on Saturday and Sunday. && .MARINE... Low pressure in was Iowa with a warm front east across northern Ohio. Winds on the lake north of the front were out of the east at 10 to 20 knots with conditions approaching small craft on the west end. Guidance suggests winds will not increase through the evening before veering through southeast to southerly by around midnight. As winds go south through, expect winds to increase off the terrain in northwest Pennsylvania bringing winds around 20 to 25 knots to the Erie PA lakeshore region. Will therefor issue a small craft advisory for that area beginning at 10pm. Will continue the headlines into Thursday evening before ending. Elsewhere, expect winds to increase to small craft levels Thursday out of the south and southwest from 20 to 25 knots as low pressure moves northeast out of the central lakes and a cold front approaches from the west. Will not issue for that yet but if guidance remains unchanged, a headlines may be required. Winds will diminish Thursday night and turn northwest as the cold front passes. Another low will move northeast through Ohio friday increasing north flow to 15 to 20 knots and possibly requiring another headline Friday into Saturday. Winds should remain 15 knots or less Sunday into Monday. && .CLE WATCHES/WARNINGS/ADVISORIES... OH...None. PA...None. MARINE...Small Craft Advisory until 10 PM EDT Thursday for LEZ149. && $$ SYNOPSIS...KEC NEAR TERM...KEC/MM SHORT TERM...TK LONG TERM...TK AVIATION...MM MARINE...TK
Area Forecast Discussion
National Weather Service Dodge City KS
602 PM CDT Wed Apr 17 2019 ...UPDATE TO AVIATION... .SHORT TERM...(This evening through Thursday) Issued at 154 PM CDT Wed Apr 17 2019 As of 18z Wednesday a surface cold front was moving into south central Kansas and northwest Oklahoma. RAP and SPC Mesoscale Analysis page both indicated that the better instability earlier this afternoon was located near this boundary and ahead of an upper level trough approaching from the southwest. All the CAMS earlier this afternoon remained in good agreement and consistent with previous runs in keeping the best chance for convection this afternoon and early tonight in this region of instability which will be located south of a St John to Ashland line. Although a brief period of large hail and strong winds will be possible does look like the storm mode will quickly become linear and the hazards will shift to heavy rainfall. Thunderstorms training over the same area early tonight in some locations of Barber and Comanche counties may cause some minor water issues with some ponding of water on roadways or poor drainage areas being possible. Given the latest flash flood guidance am leaning towards not issuing any type of Flood/Flash Flood Watch but this is an area that will need to be monitored. This area of convection will taper off around 06z Thursday as the upper level trough crosses into central Kansas and our area of enhanced forcing shifts to the south southeast. As the upper wave moves east the skies across southwest Kansas will clear and the lows overnight will bottom out in mainly from the mid 30s to the mid 40s. On Thursday another upper level disturbance will cross western Kansas during the day. Ahead of this upper wave cloudy skies along with even a few sprinkles/brief light rain showers will be possible. The area most favorable for any light precipitation during the day on Thursday will be east of highway 283. Very windy conditions are also expected to develop during the day on Thursday across western Kansas as stronger winds aloft mix down to the surface. Mean mixed layer winds generally are forecast to range from 30 to 40 knots with wind speeds at the top of the mixed layer forecast to be between 40 and 50 knots. Gusty north winds of 25 to 35 mph can be expected which when combined with afternoon relative humidity values falling back into the 20 to 30 percent range will result elevated fire weather conditions for all of western Kansas. The gusty winds will decrease early Thursday evening as an area of high pressure at the surface builds into western Kansas. At this time given the clear skies Thursday night and the location of the center of the surface high early Friday morning it appears that the temperatures early Friday morning will fall back to 32 degrees, or even a few degrees cooler, in some locations west of a Ness City to Liberal line. Further east the lows area expected to be mainly in the the mid 30s. .LONG TERM...(Thursday night through Wednesday) Issued at 154 PM CDT Wed Apr 17 2019 Warmer temperatures will return on Friday as an upper level ridge builds into the Central Rockies and 850mb temperatures start to warm as westerly downslope flow improves. HIghs in the 70s still look likely across western Kansas Friday afternoon. 80 degree temperatures will return to southwest Kansas on Saturday as the warming trend continues. In addition to these warm temperatures some gusty south winds are also expected to develop as surface pressures fall along the lee of the Rockies. These gusty winds combined with afternoon relative humidity values falling into the 20 to 25 percent range in portions of southwest Kansas will result in elevated fire weather conditions Saturday afternoon. On Sunday our next cold front will move into western Kansas as an upper level trough crosses the Rockies and moves out into the Plains. This frontal boundary will be crossing southwest Kansas a little quicker than what we were looking at yesterday and as a result it appears that clouds and cooler air returning to western Kansas during the day will result in highs only in the 60s to low to mid 70s. This will also be when our next chance for precipitation will occur also. At this time severe weather is not expected but most areas of western Kansas will have a chance of seeing some measurable rainfall, light as this may be. Next week will begin on the cool side as high pressure at the surface crosses the Central Plains. Along with cooler, more seasonal, temperatures there will also be a chance for rain Monday night and Tuesday as the next upper trough crosses the Western High Plains. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 600 PM CDT Wed Apr 17 2019 VFR conditions will prevail in the vicinity of all TAF sites through early Thursday afternoon. Northerly winds 15 to 25kt will subside somewhat later this evening with the loss of daytime heating. However, northerly winds are expected to increase 20 to 30kt with gusts up to 35kt late Thursday morning into Thursday afternoon as a secondary cold front pushes southward across western Kansas. && .PRELIMINARY POINT TEMPS/POPS... DDC 41 65 34 70 / 20 0 0 0 GCK 38 63 33 71 / 0 0 0 0 EHA 39 64 38 74 / 20 0 0 0 LBL 42 66 36 73 / 30 0 0 0 HYS 41 63 37 69 / 0 20 0 0 P28 49 67 37 70 / 90 20 0 0 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Burgert LONG TERM...Burgert AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
705 PM CDT Wed Apr 17 2019 .AVIATION... /00Z TAFS/ New cell forming south of Dryden would suggest a slight delay in convective activity around DRT, despite explosive storm growth expected in the next 1-2 hours. It`s position is well lined up the the dryline which would take about 2 hours to move that far ESE. Other cells forming over the Burro mountaintops could spread NE slightly earlier. Meanwhile CI Probabilities over the capped shower activity east of I-35 have occasionally spiked over 60 percent, but the view on satellite and out the window with ragged cloud tops does not suggest that the cap will break ahead of the organized storm clusters to the west. Meso model trends and slow onset of destabilization would suggest that the beginning of the squall lines rolling into the I-35 terminals will be at or after midnight. Severe threats will be addressed about an hour or two in advance of the cells moving into the I-35 Terminals. but only about 30-45 minutes lead time can be expected at DRT where the storms are more isolated. Rapid improvements can be expected after 08Z at SAT/SSF and 09Z at AUS. Gusty winds and fair skies should round out the end of the TAF periods with models showing the winds not picking up significantly until around 15Z or later. && .PREV DISCUSSION... /ISSUED 305 PM CDT Wed Apr 17 2019/ SHORT TERM (Tonight through Thursday Night)... Current surface observations across Texas show the dryline extending across West Texas (roughly from a Childress to Snyder to Ozona line), and the cold front pushing south across the Texas Panhandle, having just made it through Amarillo. It is this cold front that will spur on the thunderstorms expected tonight into Thursday morning. Current short-term forecast soundings and the aircraft soundings from AUS and SAT show the atmosphere still mostly capped across South Central Texas. With the capped atmosphere currently storms should hold off through the rest of the afternoon and into the early evening hours. With the dryline moving east and the front pushing rapidly south the front will overtake the dryline and be the lift that South Central Texas needs for storms. There is plenty of moisture in place with dewpoints in the upper 60s and 70s. The HRRR and other high resolution forecast models show storm initiation between 7pm and 9pm across the Edwards Plateau. When storms do initially form the discrete storms will have a very good chance of producing large hail to do the environment with 2500 to 3000 j/kg of instability/CAPE. All of the models show these discrete storms forming into a line of storms as they approach the hill country between 10pm and 1am. With 50 knots or more of bulk shear in place the severe weather threat will continue as the line approach the I-35 corridor. With the transition into a linear MCS the threat will also transition from a large hail threat to a damaging straight-line wind threat within bowing sections of the line. The line should approach the I-35 corridor between about 11pm and 2am. Based on all of this a good portion of the Hill Country and I-35 corridor have been included in the Enhanced Risk from the Storm Prediction Center, with most of the area in a significant hail hashed area as well. Basically our entire area is in the slight risk, again mainly for the large hail and the damaging wind threat. There is a low risk of tornadoes, but the main risk will be more to the NE towards the ArkLaTex region. As the storms push east of I-35 a new threat will be introduced. While rainfall totals across the area will generally be 1/4 of an inch to 1 inch, there has been increasing signals that parts of the area east of I-35 could see isolated totals as high as 2-3 inches. This could cause some localized minor flooding issues, especially in areas that have seen decent rains of late. The line of storms will continues its eastward progression and be east of the area by morning rush hour on Thursday. In the wake of the line of storms and cold front a drier airmass filters in for Thursday. As skies clear strong north and northwest winds increase. Some portions of the Rio Grande Plains could be close to wind advisory criteria. In addition, with the lower relative humidity values dropping down to 20-30 percent elevated to near critical fire weather conditions are expected across the Rio Grande Plains and Edwards Plateau. For the rest of the area afternoon highs will be a few degrees below normal from the mid 70s to low 80s. Overnight lows Thursday into Friday will also run a few degrees below normal in the low to mid 50s. LONG TERM (Friday through Wednesday)... In the wake of the upper trough that will bring storms tonight into Thursday morning northwest flow will build in aloft on Friday with sunny skies continuing. With northerly flow aloft and at the surface highs Friday will continue to run a few degrees below normal along the I-35 corridor, with near normal temps along the Rio Grande in the mid 70s to mid 80s. Southerly flow returns Saturday morning as an upper level ridge works across Texas. Highs for the weekend will warm into the 80s area wide, and should flirt with 90 degrees along the Rio Grande Plains. Clouds return on Monday ahead of the next trough, with continued seasonal temperatures. All of the long range models (GFS, Canadian, and ECMWF) show the trough approaching Tuesday, and moving across the OK/TX Red River Valley Wednesday into Thursday. With the approaching trough and the moist atmosphere rain chances begin Monday night and increase through the day Tuesday. Similar to the system moving through today a cold front will approach Tuesday night and Wednesday further enhancing rainfall. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 61 75 54 76 53 / 80 10 0 0 0 Austin Bergstrom Intl Airport 60 75 53 76 51 / 80 10 0 0 0 New Braunfels Muni Airport 59 76 52 78 52 / 80 10 0 0 0 Burnet Muni Airport 59 72 52 75 51 / 80 10 0 0 0 Del Rio Intl Airport 63 82 55 85 58 / 40 0 0 0 0 Georgetown Muni Airport 59 73 52 75 51 / 80 10 0 0 0 Hondo Muni Airport 58 79 52 82 53 / 80 0 0 0 0 San Marcos Muni Airport 59 76 52 77 51 / 80 10 0 0 0 La Grange - Fayette Regional 63 77 53 75 51 / 90 20 0 0 0 San Antonio Intl Airport 60 77 54 80 54 / 80 - 0 0 0 Stinson Muni Airport 60 77 55 80 54 / 70 - 0 0 0 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Aviation...Oaks Short-Term/Long-Term...04 Public Service/Data Collection...BMW
Area Forecast Discussion
National Weather Service Houston/Galveston TX
954 PM CDT Wed Apr 17 2019 .DISCUSSION... At 9 PM, high pressure was located over the SE US and low pressure was located over SW OK with a dry line extending south from the low across the western TX. Some light showers continue to stream into area from the Gulf but precip has remain widely scattered and generally light. All that is about to change as a line of storms approaches the region from the west. Betweem 06-09z, 300 mb winds split as an upper low over West Texas shifts east and SE TX will lie in a well defined jet couplet. The PW values surge to 1.90 inches over the western half of SE TX and there is some weak surface convergence along what looks like a weak outflow. On water vapor imagery there appears to be two short waves lined up and the first of these will approach the region around midnight and help maintain the convection over Central Texas as it approaches SE TX. Instability parameters are impressive with LI values near -10, CAPE values 2800 J/Kg and Helicity around 220. SPC has expanded the Enhanced Risk a bit east and this seems like the right call based on the instability and the approaching the short wave. SPC has also expanded the Slight Risk further east and this now includes the Houston area. AMDAR soundings still show a strong capping inversion in place at 700 mb and the million dollar question is, will the cap hold or will it break. Short term guidance has been trnding a bit more aggressively with the HRRR and TT WRF all showing convection approaching Houston around sunrise as the second short wave approaches the region from the southwest. Feel the combination of the short wave and strong upper level diffluence will help to erode the cap and allow a second area of storms to redevelop over the SW zones and move NE toward Houston and points northeastward. Instability isn`t quite as impressive as points to our west but there could still be some strong storms with gusty winds. Speaking of winds, the actual front will mot reach the coast until about 18z. The winds will become N-NW in the wake of the front and will become strong. A Wind Advisory will likely be required for a large part of SE TX Thursday afternoon. 43 && .PREV DISCUSSION... /ISSUED 704 PM CDT Wed Apr 17 2019/ AVIATION... A mix of MVFR/IFR ceilings across SE TX this evening, should continue to lower in height to IFR through the overnight hours and into tomorrow morning. Scattered light showers are continuing to develop out ahead of tonight`s cold front. E/SE winds remain gusty but should slacken ahead of the frontal passage tonight, and increase in speed out of the W/NW once again tomorrow morning. Strong to severe storms with gusty winds (primary hazard) and hail will be possible as the front passes through the region. The front should arrive at CLL shortly after midnight and reach the coastal terminals before sunrise. Ceilings will be slow to improve tomorrow morning, but anticipating VFR criteria by early afternoon area wide. Hathaway PREV DISCUSSION... /ISSUED 340 PM CDT Wed Apr 17 2019/ NEAR TERM [Through Tonight]... It has been a pretty soupy day today with overcast stratocu and continued moisture advection over SE Texas. Cloud cover has limited heating today which means there is not quite as much instability over the area as there could be and the capping inversion remains strong. AMDAR sounding from 20Z still shows a strong cap near 700mb at 12C with very steep lapse rates above that EML inversion. Surface Theta-E axis continues to run through central Texas and seeing some showers form on the eastern edge of this axis near the Brazos Valley. Right now there does not appear to be enough large scale lift to help erode the cap or a jet streak for divergence. If anything, water vapor imagery shows a jet streak departing the area so look for neutral/subsident vertical motion to continue the next few hours. The upper level low has moved into New Mexico with one part of the polar jet coming across the Big Bend and West Texas. Southern part of this jet should spread over south Texas overnight and into parts of SE Texas by 12Z Thursday. LLJ will be strong but veer around to the SW or WSW ahead of the front and strong jet forcing. There is still a very good chance of showers and thunderstorms mainly 06Z to 12Z Thursday. The WRF/HRRR continue to show a squall line moving into the area around 06-09Z with it becoming weaker 09-12Z Thursday. This is just in time for Houston morning commute from 4AM to 8AM Thursday. We still think SPC outlook is on track especially concerning the capping limiting the severe threat closer to Houston and the coast. There could be some locally heavy rainfall as well but that may depend upon available instability and lift with the higher moisture. Again capping will be the main limiting factor. Upper level lift may just be enough out of phase to keep the cap in place. These are finer details that need to be monitored overnight as convection develops and adjust based on further analysis/guidance. Overpeck SHORT TERM [Thursday Through Friday Night]... Deep upper level trough should develop east of the area over the Mississippi River Valley by Friday morning. Line of storms should be exiting the region Thursday morning as the initial trough axis moves past the area into Louisiana. A cold front at the surface should usher in cooler/drier air into the region for the holiday weekend. We will need to keep an eye on fire weather conditions as winds will be pretty gusty from the north with after RH values getting down around 30-35 percent. Overpeck LONG TERM [Saturday Through Wednesday]... Upper level ridging should continue over the area for the weekend with one short wave trough moving across the southern Plains Sunday as another trough develops over the Rockies Sunday night. GFS/ECMWF/Canadian all have fairly different solutions for the upper level pattern for early next week from Monday into Wednesday. GFS has the trough splitting with still some troughing back to the west while the ECMWF/Canadian have a slower evolution of the trough. At this point lean more on a slower moving trough which the models in some shape/form somewhat agree with on Wednesday next week. However the surface details are all very different and rather not focus on those details since we are looking at the day 6-8 part of the forecast. Forecast will show rain chances slowly ramping up Monday through Wednesday. Overpeck MARINE... Moderate to strong onshore winds and building seas are expected to develop this afternoon and tonight as the gradient tightens ahead of the incoming storm system. Showers and thunderstorms will be pushing west to east across the waters tomorrow morning with a westerly wind shift. The storm system`s cold front is still expected to push through the area in the afternoon with northwest winds increasing in its wake. There could be a period of lower winds and seas (below caution/advisory levels) just ahead of the storms and again just behind the storms, but winds and seas should come back up to those levels after the front moves through the area. Could see some minor overwash at Highway 87/124 on the Bolivar Peninsula tonight around high tide time (~4am), and then we`ll need to keep an eye on possible low water conditions late Thursday night and on into Friday morning at low tide time across northern bay locations. Winds will weaken late Friday an on into Friday night as high pressure builds into the area. Onshore winds come back to the area on Saturday and persist for the remainder of the weekend and on into at least the first half of next week. 42 && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 80 63 76 52 74 / 40 100 40 0 0 Houston (IAH) 78 66 80 54 75 / 40 90 80 0 0 Galveston (GLS) 76 70 78 60 74 / 40 60 80 0 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...NONE. GM...SMALL CRAFT SHOULD EXERCISE CAUTION until 6 AM CDT Thursday for the following zones: Galveston Bay...Matagorda Bay. Small Craft Advisory until 6 AM CDT Thursday for the following zones: Coastal waters from Freeport to Matagorda Ship Channel TX out 20 NM...Coastal waters from High Island to Freeport TX out 20 NM...Waters from Freeport to Matagorda Ship Channel TX from 20 to 60 NM...Waters from High Island to Freeport TX from 20 to 60 NM. && $$ Discussion...43
Area Forecast Discussion
National Weather Service Lincoln IL
910 PM CDT Wed Apr 17 2019 .UPDATE... Issued at 908 PM CDT Wed Apr 17 2019 The line of storms is progressing along at a timing that is close to the CAMs recent projections. Instability remains the primary focus for storm intensity, with shear generally on the marginal side. DCAPE values of 600-800 J/kg appear sufficient to support some pockets of damaging winds from the stronger updrafts. A few hail cores could reach up to nickle size, but strong winds should be the primary severe threat overnight. Instability does weaken with time overnight, so the initial wave of storms between midnight and 3 am will have the better chances of producing the stronger winds and possibly severe hail. Surface based instability will be difficult to maintain overnight, with areas of dewpoints in the 60s have the best chance at that. The I-55 corridor currently has some dewpoints in the low 60s, so will monitor that area for higher threat of severe winds. The severe threat will continue east of I-55 between 3 am and 6 am, with pockets of strong winds possible. But overall severe potential should diminish the later in the night the line progresses toward Indiana. Updates this evening were to delay the PoPs and storms a couple of hours, to late evening start times. Otherwise, the remainder of the night looks on track. Strong southwest winds will continue ahead of the cold front, then weaken as the front nears and passes. Gusty NW winds will lag the FROPA by a few hours, but gusts look to return to 15 to 25 mph again early Thursday morning west of I-55. && .SHORT TERM...(This evening through Thursday) ISSUED AT 305 PM CDT Wed Apr 17 2019 Shortwave over IA and surface low to track east overnight, dragging frontal zone eastward, reaching northwest IL by 06z. Good moisture advection moving northward over MO into east IA and northwest IL/southern WI. Hi Res short range models develop convection in frontal zone over MO in strong southward inflow into convergence zone. Convection then trails off to east into IL over night. Time of the day may be a hindrance on severity of convection, as CAPEs should decrease overnight, but latest HRRR models still move significant linear convection across area. Frontal zone pcpn to continue to sag east til early morning hours. Some heavy rain possible with some storms. Lingering convection through Thursday, mainly in the east. Most of this will be post frontal and so the severe nature of storms will be limited and scattered. Heavy rain biggest threat. .LONG TERM...(Thursday night through Wednesday) ISSUED AT 305 PM CDT Wed Apr 17 2019 For friday, still have some wrap around showers on back side of the upper system that is progged to be over mid Atlantic states. Dry surface ridging over area through Saturday and into start of Sunday. For Sunday though, next frontal zone progged to move into from the northwest, reaching central IL by evening. Overrunning pcpn to develop due to front in the plains, and models a little different on eastward development. Both EUR and GFS do agree on pcpn in region on Sunday night, but differ in the position of the front, with the EUR farther to the south as the that model has Great Lakes upper trough stronger and the upper wave in the southwest weaker. Be Tuesday to Wednesday, EUR model has front further south of central IL. WPC frontal graphics went more with EUR trends. As result, spotty areas of low pops off and on into Wed. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 704 PM CDT Wed Apr 17 2019 A line of storms is expected to push across the TAF sites from late evening to early morning, as a cold front advances from Iowa to Indiana overnight into Thursday morning. MVFR clouds are likely to develop as the storms arrive, with IFR clouds and visibility possible for shorter periods of time as thunderstorms pass over any TAF site. Timing looks to be from west to east starting at PIA and SPI around 04-05z, then reaching CMI to DEC between 08z-09z. Rain and showers will likely linger on Thursday for the eastern terminals, as the frontal boundary slows down in E-SE Illinois. A few morning thunderstorms will also be possible for CMI and DEC mainly. Winds look to remain gusty from the SW this evening, at 15g30kt early, diminishing to 10g20KT by mid evening, then around 5-10kt as the cold front approaches/passes each TAF site. Winds will shift to westerly later tonight, then become NW and increase to 12g22KT by 17z-19z in most areas. Ceilings look to improve from low MVFR around sunrise, to VFR by mid to late afternoon. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Shimon SHORT TERM...Goetsch LONG TERM...Goetsch AVIATION...Shimon
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
924 PM CDT Wed Apr 17 2019 .UPDATE... Updated for evening discussion. && .DISCUSSION... Tightening pressure gradient over central sections has resulted in some gusty winds this evening. This will be the trend overnight with a gradual increase in speeds toward morning. The latest HRRR data continues to show the brunt of the convection coming into the area after 15Z. Remainder of forecast package still looks good. No other significant changes expected./GG/ Prior discussion below: Through tomorrow night... Shortwave ridging over the region today will lift off to the northeast as a strong shortwave trough ejects out of the Desert Southwest and into the Southern Plains before lifting through the Lower Mississippi River Valley tomorrow. Capping will keep rain chances confined to an isolated shower or two over the far northwest Delta today before rain chances quickly ramp up tomorrow morning. Upstream showers and thunderstorms will progress across the ArkLaTex overnight with decaying convection progged to stall over portions of the Delta during the early morning hours. A few of these early storms could be severe with damaging winds, hail up to quarter size, and a tornado or two cannot be ruled out. Lee side cyclogenesis will occur over the High Plains with the main low lifting northeast into the upper Midwest by tomorrow morning with an attendant cold front draped through the Mississippi River Valley. A perturbation propagating along the frontal boundary over east Texas will help induce a second area of cyclogenesis beneath favorable upper jet dynamics with a deepening low (~995mb) lifting through southern Arkansas into far northern Mississippi through the day tomorrow. Resulting low-level mass response will help enhance the wind fields with flow strengthening as it becomes increasingly backed yielding veering wind profiles with height and strengthening vertical wind shear, especially in the 0-1km layer. This will be occuring within a warm sector characteristic of upper 60s dewpoints and 1000-1500 J/kg of MLCAPE which will be supportive of organized severe convection. This morning`s hi-res CAM guidance is in fairly good agreement on possible convective evolution depicting an area of warm air advection convection, including the potential for semi- discrete supercells, lifting northeast into southern Mississippi ahead of a strongly forced and intense QLCS. As strong surface pressure falls and mid-level height falls overspread the area eventual upscale growth into a solid line of storms is expected. In terms of hazards, tornadoes, of which a strong tornado cannot be ruled out, damaging straight line winds of 70-80mph, and hail up to quarter size are all expected. The ongoing enhanced risk area will be maintained in the HWO/graphics. In addition, flash flooding will be a concern with anomalous moisture in place as PWATs surge to near 2". Training convection with high rainfall rates will result in 2-4" of rain with locally higher amounts over a short amount of time which will lead to flash flooding issues. A flash flood watch has been posted for all areas except the far southwest corner of the CWA and the HWO/graphics have been updated to include an elevated threat area. There are two main areas where swaths of higher QPF could be realized. The first will be over the Delta where early morning training convection will be possible, and the second area is roughly from Brookhaven to just north of Meridian where warm air advection storms could train ahead of the main line. Storms will exit the area into Alabama by the early evening hours, although a few showers could linger through the overnight. Temperatures tonight will be mild as mixing and moisture advection beneath increasing cloud cover preclude greater cooling potential. Locations across eastern Mississippi ahead of the line of storms could warm close to 80 tomorrow with other locations remaining in the low to mid 70s. /TW/ Friday through Tuesday night... The main system from Thursday will exit the region around Friday morning but a short wave trough with a positive tilt axis will allow for some rain wrap and moisture bringing in some lingering cloud cover and showers for the rest of the day. By Saturday all precip will have cleared the area. Some slight northwesterly flow will persist bringing in cooler temperatures for the morning but will shortly get replaced as a upper ridge builds out west Sunday. This will bring increasing heights and with the influence of southerly flow, highs will climb to near 80 degrees F. For next week, there is some discrepancies within the models as the GFS shows a more profound ridge and the Euro and Canadian favoring a weak trough with a possible stalling front. With the chance of this front possibly hanging over to the north west which will increase moisture, a low chance of PoPs were added to account for that. With models still in disagreement for the later work week only minor changes were made to the extended forecast. /JE/ && .AVIATION... 00Z TAF discussion: VFR ceilings will increase and lower tonight eventually becoming MVFR prior to sunrise. Isolated to scattered showers and thunderstorms will begin developing from the west after sunrise. While ceilings will mostly become VFR by afternoon, they will quickly be lowered to MVFR/IFR when showers and thunderstorms move through. Winds will increase to 10 to 15 knots from the south with gusts around 25 knots during the afternoon./GG/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 62 76 51 62 / 5 99 54 37 Meridian 62 79 52 62 / 10 99 97 38 Vicksburg 65 75 52 65 / 7 99 47 31 Hattiesburg 63 80 53 64 / 10 99 97 34 Natchez 65 77 51 65 / 6 100 47 32 Greenville 66 72 50 63 / 17 99 51 23 Greenwood 64 74 50 61 / 4 99 62 35 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Flash Flood Watch from 7 AM CDT Thursday through Thursday evening for MSZ018-019-025>052-054>058-062>066-072>074. LA...Flash Flood Watch from 7 AM CDT Thursday through Thursday evening for LAZ007>009-015-016. AR...Flash Flood Watch from 7 AM CDT Thursday through Thursday evening for ARZ074-075. && $$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
939 PM EDT Wed Apr 17 2019 .SYNOPSIS... High pressure over the western Atlantic will continue to influence the weather through Thursday. A strong frontal system will impact the area Friday into Saturday. High pressure will build into the region early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... As of 930 PM Wednesday...No adjustments were made to the previous forecast. Despite a slow temp fall due to high clouds and a slight southerly breeze, stuck with our lows in the middle to upper 50s tonight. Hourly temps now match up well with the RAP and HRRR which still shows lows tonight around what we already have. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... As of 345 PM Wednesday...High pressure offshore begins to slide eastward as the frontal system continues to advance toward the region. Dry weather continues as the mid levels remain very dry but will see increasing high clouds through the day with sct cumulus during the afternoon as southerly flow brings increasing low level moisture. It will be another warm day with highs in the low to mid 80s inland to mid to upper 70s along the coast. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 325 PM Wed...Dry but increasingly cloudy conditions give way to a very strong storm system passing inland Friday, bringing a cold front and a myriad of associated hazards across the area later Friday into Sunday morning. Dry weather is forecast to prevail into mid-week. Thursday night through Saturday...An exceptionally high amplitude upper trough (500 mb geopotential height > 3 standard deviations below normal based on NAEFS) digging across the eastern US will develop a cutoff/stacked low over the Mississippi and Tennessee Valleys Thursday night into Friday. This low, in combination with the persistent high offshore, will help develop deep layer southerly flow/moisture advection locally. Cloud cover will increase overnight, with eastern NC experiencing mostly cloudy skies Friday. The increased cloud cover, combined with the development of isolated to widely scattered showers forecast early Friday in a conditionally unstable airmass, will help limit instability and thus severe potential during the day. Severe risk increases Friday evening as the stacked low moves over the southern Appalachians, with very strong winds on its east side throughout the column. Guidance continues to show a LLJ with winds of 50-60 kt at 925 mb ahead of a cold front that will cross the area Friday night into Saturday morning. Gusty to strong winds will arrive with the jet, especially for coastal areas, and a Wind Advisory appears likely in future packages. A High Wind Warning is possible for the Outer Banks. There is a risk of minor coastal flooding for the northern Outer Banks mainly north of Oregon Inlet. Additionally, the primary band of prefrontal moisture convergence will cross the area Friday night and despite continued limited instability (about 1000 J/kg per ensemble guidance), showers and thunderstorms will bring the potential for damaging wind gusts as they readily mix the very strong LLJ winds to the surface. An isolated tornado threat and heavy downpours leading to localized minor flooding are also possible with the strongest convective cells. The cold front will be near the coast by sunrise Saturday, and push off the coast through the day. True CAA will not occur immediately behind the cold front as the stacked low lifting across the Great Lakes will remain in control, bringing atypical post-frontal southwesterly flow. However, subsidence aloft will bring settled conditions despite the lack of significant low level airmass change. Sunday through Tuesday...Subtropical high pressure is expected to ridge into the area early next week, bringing rain-free conditions and near to above normal temperatures. A backdoor cold front may make an approach towards our region during the period, but despite model timing differences this feature currently does not look like it will bring any sensible weather impacts. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Short Term /through Thursday/... As of 730 PM Wednesday...High confidence that VFR conditions will dominate through the TAF period as dry high pressure continues over the area with light winds and high Cirrus clouds. Could see patchy light ground fog briefly early Wed morning where winds partially decouple but it is not expected to have significant impacts at the TAF sites. Pressure gradients begin to tighten Thursday with the approach of a frontal system and could see peak gusts up to around 20 kt during the afternoon but gusty conditions will begin by mid morning as soon as we get a bit of mixing. Long Term /Thursday night through Monday/... As of 325 PM Wed...VFR conditions initially Thursday night will deteriorate beginning early Friday as a frontal system approaches from the west. This front will bring the potential for widespread sub-VFR Friday into Friday night with showers and thunderstorms impacting the terminals at times. Additionally, very gusty winds will occur ahead of the front, especially near storms, as a strong LLJ moves overhead late Friday. Low level wind shear is also expected during this time. More settled (VFR) conditions will gradually ensue again on Saturday and dominate through early next week. && .MARINE... Short Term /through Tonight/... As of 930 PM Wednesday...Quiet conditions on the waters this evening with southwest winds 10 to 15 knots and seas 2 to 3 feet. High pressure to our east now will continue to move eastward Thursday as a strong frontal system approaches from the west bringing tightening pressure gradients. Winds will become S/SW around 5-15 kt throughout this evening and continue overnight, then S winds increase to 15-20 kt on Thursday. Seas will generally be around 2-3 ft tonight into Thursday morning, then build to 3-5 ft by late afternoon. Long Term /Thursday night through Monday/... As of 325 PM Wed... Conditions deteriorate Thursday night as a very powerful low pressure system begins to impact the southeastern US. Strong winds ahead of an approaching cold front will bring a high confidence gale event beginning early Friday morning and continuing through Friday night. Storm Force winds are possible mainly across the coastal waters from Oregon Inlet to Cape Lookout Friday night. Accordingly, seas will rise rapidly beginning late Thursday night, with seas that are very dangerous for all size vessels, as high as 18 to 20 ft within 20 NM of Hatteras Island, occurring Friday night. Overall, extremely dangerous marine conditions are on tap Friday and Friday night. The cold front will cross the waters Saturday morning, and conditions will begin to improve through the day Saturday, though SCA winds and seas will likely linger into Saturday night and possibly Sunday. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...EH/SK SHORT TERM...SK LONG TERM...MS AVIATION...EH/SK/MS MARINE...EH/SK/MS
Area Forecast Discussion
National Weather Service Marquette MI
627 PM EDT Wed Apr 17 2019 .SHORT TERM...(This evening through Thursday) Issued at 415 PM EDT WED APR 17 2019 WV imagery and RAP analysis indicated a mid/upper level trough the northern and central Plains with a well defined shortwave into southwest WI. Radars indicated moderate to heavy rain from eastern MN through northern MN with embedded tsra on the srn portion of the rain area. At the surface, low pressure was located over nrn IA with a warm front through far nrn IL. Radar/satellite trends suggest that the heavier rain associated with the comma head portion of the shrtwv will move through mainly western Upper Michigan. However, stronger moisture transport and low isentropic lift will also support heavier rain through the southeast half of the cwa especially as a trailing shrtwv over IA moves toward the area by late evening. In addition, forecast MUCAPE values at or above 500 J/Kg suggest tsra will also be more likely over the south. The combination of rainfall to around an inch and additional snowmelt could result in minor flooding on small streams and significant ponding water. Increasing CAA behind the low will draw enough colder air into the west for a mix or change to snow toward 06z, per NAM wet-bulb zero height forecasts. Snowfall amounts of an inch or two may be possible overnight. Thursday, moist northerly upslope flow will support continued lake/terrain enhanced rain/snow over the west half in the morning that will gradually taper during the afternoon. Any additional snow amounts will be less than an inch. Otherwise, colder conditions return with blustery north winds and highs in the lower 40s. .LONG TERM...(Thursday night through Wednesday) Issued at 427 PM EDT WED APR 17 2019 During the long term, a lower amplitude, split flow pattern will become the rule across the CONUS/southern Canada with the northern stream dominant. After the mdt to potentially hvy rainfall tonight and then the snowmelt that will be occurring into and thru next week, this pattern will fortunately be a drier one for Upper MI. Even so, will likely see some river flooding develop over time. There will be 2 northern stream shortwaves affecting Upper MI during the long term, one Sun and the other midweek. With little moisture avbl with the first wave, rain chc will be limited as the wave passes on Sun. The next shortwave will bring a chc of rain at some point in the midweek period. As for temps, after a chilly Thu, sunny days under a dry air mass Fri/Sat will lead to significant warming with highs on Sat well above normal over the w. Passing cold front late Sat night and Sun will bring some cooling, most notably near Lake Superior. Then, temps Mon thru Wed will be close to normal, but probably leaning above normal in areas not affected by lake moderation. Beginning Thu night/Fri, if there is any lingering -ra/-dz late Thu aftn, it will end from w to e Thu evening, followed by clearing skies into Fri. Deep, dry air mass on Fri will support sunny skies or clearing to sunny skies where any clouds still linger to start the day. Temps will respond by rebounding into the 50s, except near Lake Superior. Stronger gradient flow across Lake Superior into the eastern fcst area will keep temps lower in that area, and no higher than around 40F close to the lake. Given the very dry air avbl for mix down as the boundary layer builds during the day, incorporated some of the drying based on mixing heights to lower dwpts during the aftn. Clear/quiet night Fri night under passing sfc high pres ridge will be followed by a warm day on Sat, especially so over western Upper MI under southerly flow. With sfc high pres ridging back to eastern Lake Superior and northern Lake MI, it will be cooler over the e, particularly along the Lakes. Will turn cooler thru the day over the Keweenaw and along the lake over the n central as winds back under developing lake breeze wind component. Over the w, a continued dry air mass and 850mb temps around 5C will support temps rising well into the 60s. Some of the traditional warm spots may touch 70F. Given the still very dry air avbl for mix down as the boundary layer builds during the day, once again incorporated some of the drying based on mixing heights to lower dwpts during the aftn. Shortwave will shift e to northern Ontario by Sun morning. There is quite a spread among the models in timing the associated cold front across Upper MI. The GFS has the front exiting the fcst area by 12z Sun, the ECMWF during the aftn and the CMC not until Mon morning. ECMWF has shown good consistency on the timing and fcst will lean in that direction. With limited moisture and modest forcing, not expecting much for shra activity in the vcnty of the front as it passes. Clearing will follow. While it will be chilly or become so near Lake Superior where w to nw winds are onshore Sun, it will still be warm inland. Over the s central, downsloping postfrontal w to nw winds will help push temps back above 60F. High pres will build se across northern Ontario and the northern Great Lakes on Mon, providing a mostly sunny, but cooler day. Temps will reach the 50s well inland from Lake Superior. Along the lake, temps will be no higher than the upper 30s/lwr 40s. Next shortwave will arrive midweek, bringing a chc of shra. GFS is an outlier, showing more of a southern stream link up which results in a much wetter period. However, there is not much support for such a solution from the GFS and CMC ensembles. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 627 PM EDT WED APR 17 2019 Expect rain to continue as a low pressure system moves to southeast Minnesota and an associated warm front lifts across Wisconsin and lower Michigan. Plan on conditions deteriorating to IFR or lower in periods of rain and fog at all sites this evening as the low pressure system lifts tracks toward northern lower Michigan. Enough cold air will occur in the low levels for the rain to mix with or even change to snow at KCMX by late this evening. Northerly upslope flow will maintain IFR/LIFR conditions for much of Thursday at all sites. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 415 PM EDT WED APR 17 2019 As low pressure approaches the region, NE winds will increase to 25 to 30 knots tonight and then become N Thursday morning and diminish to around 20 knots Thursday afternoon and Thursday night. Expect diminishing winds Friday with winds below 20 knots through the weekend. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Rolfson AVIATION...07 MARINE...JLB
Area Forecast Discussion
National Weather Service Springfield MO
657 PM CDT Wed Apr 17 2019 ...Mesoscale Discussion and Update to Aviation... .MESOSCALE DISCUSSION... Issued at 629 PM CDT Wed Apr 17 2019 A few storms have fired early this evening along a boundary extending northeast from near Eureka to Garnett, KS and then into the eastern Kansas City metro. This boundary has been slowly lifting north over the last hour. Farther southwest along this boundary, thunderstorm activity is more numerous in northwest OK. Meanwhile a synoptic cold front extends from just south of St. Joseph, MO to near Topeka to Hutchison, KS. Storms have started to fire along this front in northwestern Missouri and extreme northeastern Kansas. Activity along this front should backbuild to the southwest this evening rather quickly, especially as it reaches the other boundary. Meanwhile, the 00Z KSGF RAOB indicates that a fairly strong capping inversion remains in place across the Ozarks. We therefore think that thunderstorm potential will come in two phases from later this evening into the overnight period: 1) Widely scattered activity developing in the warm sector across northern Arkansas and southern Missouri later this evening as a low level jet stream strengthens and noses into the region. Thunderstorms would tend to be elevated in nature, but could pose a hail threat. 2) Scattered to numerous storms along the cold front starting around 9-10 PM over extreme southeastern Kansas and west-central Missouri. These storms will then sag southeast with time along that front overnight. Hail up to the size of golf balls will be possible with any discrete storms. Otherwise, severe hail size potential will generally be in the quarter to half dollar range. There will be a damaging wind threat with the line of storms. This will especially be true with any bow echoes that move out of Kansas and Oklahoma. It should be noted that CAMs and several runs of the HRRR have indicated this potential, especially across southeastern Kansas and southwestern Missouri. The tornado threat remains limited and will be confined to any bow echoes which surge towards the northeast. We will have to pay particular attention to any bow echoes tracking northeast along any quasi-stationary outflow boundaries that may be present. The threat for flooding looks very low at this point given that this cold front and expected line of storms should remain fairly progressive. && .SYNOPSIS... Issued at 225 PM CDT Wed Apr 17 2019 Visible satellite and observations continue to show a stratus layer across the area and special 18z SGF sounding continues to show EML above the stratus deck. Cold front stretched from western Iowa into northeast KS and into the TX panhandle. Regional radar was showing most of the convection at this point associated with the low in Iowa and Minnesota, although some storms have started to now form in the Texas panhandle. Most of the region still had a thermal cap in place and should prevent convection from developing until very late afternoon or early evening along the cold front. The storms will be the main focus in the short term. && .SHORT TERM...(This evening through Thursday) Issued at 225 PM CDT Wed Apr 17 2019 As mentioned in the synopsis, 18z soundings from SGF into the southern plains showed a thermal cap in place which will likely hold until this evening when convection should start to develop along the front. The front will gradually work southeast into the area this evening with strong to severe storms. By this time, we are expecting most of the convection to become linear with the frontal boundary with the main risk being damaging straight line winds and some hail. If any bowing line segments can develop towards the northeast, there could be a chance for a spin-up tornado within the line segment. Most of the area will have a time frame from mid-evening into the overnight hours for the severe potential. Don`t see much of a flooding risk, given the green-up taking place and the progressive nature of the front, although heavy rain is expected with the convection. The convection will linger into Thursday morning over the eastern Ozarks, but should come to an end during the afternoon hours. If there is enough instability, then some strong to severe storms will remain possible. .LONG TERM...(Thursday Night through Wednesday) Issued at 225 PM CDT Wed Apr 17 2019 Cooler temperatures will linger into Friday as the back side of the upper low continues to push through. Highs will be from the upper 50s to mid 60s. We should begin to warm back up over the weekend, into the 70s as an upper ridge builds in behind the upper trough. Models do show some differences with the strength and timing of the next energy on Sunday, but both have some showers/thunderstorms possible by late in the day into Sunday night. It looks to remain unsettled through the remainder of the long term period with a slow moving upper trough and low closing off over the region by the middle to later part of next week. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 629 PM CDT Wed Apr 17 2019 Scattered to numerous thunderstorms are expected overnight along an advancing cold front. MVFR conditions will become likely overnight with gusty and erratic winds also expected around storms. There is then some potential for IFR early Thursday morning behind the departing thunderstorms. Otherwise, MVFR is expected Thursday morning with northwest winds increasing behind the front. VFR should then return Thursday afternoon. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ MESOSCALE...Schaumann SYNOPSIS...Lindenberg SHORT TERM...Lindenberg LONG TERM...Lindenberg AVIATION...Schaumann
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Thursday) Issued at 317 PM CDT Wed Apr 17 2019 Focus through late tonight remains on thunderstorms chances and their impacts. Central Plains remains flanked by main two upper level systems to the north and south. Surface cold front is somewhat ill-defined with an apparent boundary from near Marysville to Abilene, and another from Medicine Lodge to near Lubbock TX at 19Z. Isolated convection has persisted to the north and northeast along the northern boundary early this afternoon with visible satellite trends also not supporting rapid destabilization despite RAP analysis suggesting little convective inhibition. Low clouds ahead of the front remain rather persistent and are keeping strong heating and mixing in check. Most guidance is similar in scattered to numerous convective cells developing around 0Z along a consolidated front in southern portions of the local area, however some rapid-updating solutions keep some separation to the aforementioned boundaries into the early evening. The persistent cloud suggests inhibition remains considerable and expect the stronger convergence that develops late today will be needed for the most convection to occur, but will keep some small chances along the northern boundary early on. Deep shear remains fairly strong though vectors are oriented along the boundary and suggest somewhat unorganized and varied storm motions and types and should keep concerns limited to hail and wind. Synoptic boundary is rather slow moving and there will be some potential for training though outflow from any segments moving off the line could push the effective front south to keep persistent heavy rains to the southeast. Southern upper trough should reach central portions of Oklahoma well before dawn and usher the front well southeast by late tonight. Deep north-northwest flow develops Thursday as a weaker wave rotates around the consolidating upper trough. Cool temps aloft and meager low level moisture may allow for isolated to scattered showers to form with diurnal mixing in much of the area Thursday afternoon. Pacific nature to the airmass brings highs back into the lower to middle 60s. .LONG TERM...(Thursday night through Wednesday) Issued at 317 PM CDT Wed Apr 17 2019 Winds Thursday evening back off as skies clear but expect temps to remain above any frost concern. Northerly flow continues into Friday night as the upper trough deepens to the southeast and a northerly low-level wind component to the winds across the western Gulf of Mexico through early Saturday. Multiple upper troughs work their way east into the western and central Plains Sunday into at least Tuesday with much to be determined on their placement and timing. The aforementioned Gulf wind character should keep instability and moisture muted but at least diurnal thunderstorms will be possible. There is general agreement for upper ridging to return around Wednesday for lesser precipitation chances. Temperatures should remain relatively close to normal in this regime. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 630 PM CDT Wed Apr 17 2019 Maintained a VFR forecast for the terminals through the night. There may still be a window of opportunity for showers or perhaps an elevated thunderstorm over the next several hours generally through 06Z. However, as the cold front continues to advance south this opportunity may wane quicker. Expect winds to increase overnight into the morning from the northwest. May need to increase the gusts in subsequent forecasts. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...65 LONG TERM...65 AVIATION...Drake