Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/17/17

Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
553 PM MDT Sun Apr 16 2017 .AVIATION... 00Z TAF CYCLE Hit and miss storms will impact the NE third or so of the state this evening and potentially overnight. Outflow winds will mess up the wind field for a time and also help push abundant moisture further south and west. Confidence is pretty decent for some low cig/vis impacts at LVS/TCC least for a few hrs. Less confidence at ROW and SAF where models show some potential. Also less confident on start and end time of the impacts. Otherwise...VFR conditions expected next 24 hrs. Another round of convection or storms will dvlp Mon afternoon across the east but once again hit and miss and most likely wont directly impact terminal sites although will be monitoring model trends on that. 50 && .PREV DISCUSSION...300 PM MDT Sun Apr 16 2017... .SYNOPSIS... Low level moisture will further invade the eastern plains tonight, with areas of low clouds or fog likely to develop over the northeast and east central. An area of instability over the northeast and east central will lead to thunderstorm development as well tonight, and a few storms could become strong to severe. A transition to drier and warmer weather begins Monday afternoon with diminishing chances for showers and storms in the east. Temperatures will be around 5 to 15 degrees above average Tuesday and Wednesday as west winds strengthen, leading to areas of critical fire weather conditions across the east on Wednesday. Another front will impact the east Thursday and Friday, while a disturbance drops into north central New Mexico. This could kick off showers and storms over the north and east, as well as cool high temperatures on Friday to 5 to 10 degrees below average. && .DISCUSSION... Although low clouds have eroded away in the northeast, the relative lack of cumulus at the moment isn`t encouraging for storm development. HRRR and RAP13 not so enthused about precipitation over the northeast third tonight, so considered trimming areal coverage of pops somewhat. However, LAPS indicates portions of northeast NM and the east central along the TX border destabilizing more with each hour this afternoon, so will maintain the inherited forecast for this evening including the mention of isolated strong to severe storms. Otherwise, HRRR suggests the low level moisture may reach the east slopes of the Sangre de Cristo and Sandia/Manzano mts, and could seep into the middle RGV on a weak to barely moderate east wind after midnight. MET and MAV guidance also follow this trend, but not thinking the moisture will be sufficient to initiate any convection Monday and should mix out. Also put some areas of fog from the CAO-CVS area overnight and Monday AM. Guidance high temperatures for the east Monday have all increased some, so warmed highs a bit but not as much as the guidance. Will depend on how quickly the low cloud/fog coverage dissipates. Drier air makes more progress over the region Tuesday and Wednesday. Westerly winds increase Wednesday but not overly strong for spring. High temperatures warm to around 5 to 15 degrees above average both days. More unsettled weather forecast Thursday into the weekend. A cold front will impact the east Wednesday night/Thursday and again Friday night/Saturday, with possibly a reinforcement Saturday night/Sunday. Meanwhile, a disturbance/closed upper low swings over north central and northeast New Mexico. The initial front and disturbance/upper low could kick off showers and storms over the north and east, as well as cool high temperatures on Friday to 5 to 10 degrees below average. Highs Saturday remain about 5 to 15 degrees below average but chances for precipitation taper off. It`s not out of the question meager snow accumulations might occur Friday night over the the far northeast. && .FIRE WEATHER... In the wake of last night`s back door cold front, moisture will continue to increase tonight through Monday most places. There is a slight chance of showers and thunderstorms from the east slopes of the Sangre de Cristos eastward and southeastward across the eastern plains overnight. Widespread low clouds and some patch fog are also expected across much of the plains. A few storms may return along the east slopes of the Sangres Monday afternoon. Widespread Haines of 6 is also expected Monday. Tuesday and Wednesday an upper level trough will pass north of New Mexico causing winds aloft to strengthen and a surface lee trough to develop. This will result in breezy conditions with locally critical fire weather conditions across northeast areas Tuesday, then critical fire weather conditions will become widespread along and east of the central mountain chain Wednesday. Haines mainly in the 5 to 6 range is expected Tuesday, then in the 4 to 6 range Wednesday. High temperatures will also be well above normal both days, so there is a risk of a fire weather headline across the eastern half of the forecast area on Wednesday. In the wake of the upper level trough a back door cold front will dive southward through the eastern plains on Wednesday night. This front is forecast to increase humidities above critical thresholds in most places along and east of the central mountain chain for Thursday. However, most central and western locations will remain very dry. Another upper level trough will pass eastward over the NM/CO border late Thursday through Friday, forming a closed upper level low pressure system in the lee of the Sangre de Cristos on Friday. Winds will strengthen ahead of this system across central and western areas on Thursday, with a risk of some fairly widespread critical fire weather conditions from the Manzano and Gallinas Mountains west and northwestward across the west central mountains including Gallup. Areas of super Haines are also expected in the Rio Grande Valley Thursday afternoon. Winds will then become breezy to windy most places on Friday; however, a surface cold front will drop into northern areas on Friday as the closed upper level low pressure system forms. This will enhance moisture across northern areas, but most of the area south of I-40 can expect critically low humidities. Haines in the 3 to 5 range and temperatures varying from around 2 degrees above normal to 6 degrees below normal could preclude the need for a fire weather headline Friday afternoon. Locations along and east of the northern mountains will have a chance for showers and thunderstorms late Thursday through Friday. Then, there will be a chance of snow showers in the northern mountains Friday night as moisture wraps around the exiting upper low. A secondary perturbation dropping out of the north could cause some showers to linger in the northern mountains Saturday, but overall the weather will be drier with calmer winds. An exception may occur along the eastern border where breezy north winds may linger due to a back door cold front on Saturday. && .ABQ WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Cheyenne WY
250 PM MDT Sun Apr 16 2017 .SHORT TERM...(This evening through Tuesday night) Issued at 300 PM MDT Sun Apr 16 2017 Forecast challenges mainly on severe thunderstorm chances for the Panhandle Monday afternoon and evening. Currently...Pretty nice day ongoing across southeast Wyoming and Nebraska Panhandle so far. Temperatures much warmer than yesterday with upper 50s west of the Laramie Range and mid 60s out in the Panhandle at 1PM this afternoon. Surface analysis showing an area of low pressure just north of Cheyenne. Water vapor showing a fairly potent low pressure area just off the coast of northern California. Fire weather wise, we are seeing afternoon humidities down near 15 percent this afternoon with wind gusts close to 25MPH. May need to do a short fused Red Flag for FWZ 306 and 309, but for now, will hold off. GFS soundings showing wind speeds easing through the afternoon. Will continue to monitor. Attention turns to convection this afternoon. Not really too concerned with convection today. Taking a look at the CU around the office, still fair weather CU with little to no vertical extent. Latest SPC Mesoanalysis showing instability developing east of the Panhandle later this afternoon and evening. HRRR not even showing any development over southeast Wyoming on its simulated radar forecast with only very spotty convection over the southern Panhandle. Kept a 20 percent chance of precip over the southern Panhandle for early this evening, then drying out after 02-03Z. Guidance continues to show that low off the northern California coast moving inland tonight and across northern Wyoming/southern Montana Monday afternoon. low level moisture pooling into the Panhandle with the NAM showing TDs increasing into the low 50s by Monday morning. Did increase TDs across the Panhandle from what guidance was showing, but did not go as high as the NAM. Pretty unstable out there tomorrow afternoon with Lifted Indices of -7 to -8C. MUCAPES around 1250 to 1500 J/KG with strong 0-6km shear 35-40kts. Developing dryline set to push into the Panhandle from eastern Wyoming during peak heating tomorrow should be good for a few discreet supercells to develop across the Panhandle late afternoon through early evening. Did add severe thunderstorm wording back into the forecast for the Panhandle during that time. A more widespread precip event is forecast for Tuesday as our next cold front moves into our western counties Tuesday afternoon. .LONG TERM...(Wednesday through Sunday) Issued at 300 PM MDT Sun Apr 16 2017 A vigorous/fast moving upper-level disturbance is progged to track eastward across the central Rockies on Wednesday. The GFS/ECM both are in good agreement w/ surface cyclogenesis from east central CO into northwest KS. A fairly extensive band of precipitation should occur across much of the CWA associated w/the mid-level TROWAL and the LFQ of a 100+ knot H25 jet. A brief break from widespread pcpn on Thursday with a transitory ridge overhead. A stronger shortwave and associated cold front is expected to dive southeast across the western US later on Thursday through Friday. H7 temps will fall to -4 to -6 deg C by 00z Sat, w/ southeasterly low-level upslope east of the Laramie Range likely contributing to a good chance for rain or snow for a widespread area on Friday. Highs are likely to be on the cool side as well, struggling to get out of the 40s. It is too early to say much on the snow potential for lower elevation areas, mainly due to fairly warm low-level temperatures. However, a trend toward colder temperatures has been observed over the last several days so we will continue to monitor closely. && .AVIATION...(For the 00Z TAFS through Monday afternoon) VFR conditions will continue through late this evening with a few thunderstorms near KSNY until 02Z. IFR conditions are looking more likely at KSNY between 09z-15z late tonight, with low CIGS and the possibility of fog. This fog may also impact KBFF and KCYS as well, but confidence is not high at this time. conditions will improve by late Monday morning with a good chance for thunderstorms from KSNY northward to KCDR by mid-late Monday afternoon. && .FIRE WEATHER... Issued at 300 PM MDT Sun Apr 16 2017 near critical fire weather conditions will continue this afternoon as humidities are near 15 percent and wind gusts are close to 25 MPH. Given that fuels are in the beginning stages of greenup, will hold off on any warnings though this afternoon. For most part though, critical winds should stay below thresholds. Increased chances for wetting rains Monday, especially for FWZ 311 through 313 where showers and thunderstorms are expected to be most numerous. Widespread wetting rain expected Tuesday into Wednesday as a front moves into the area from the northwest. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...GCC LONG TERM...CLH AVIATION...TJT FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Dodge City KS
612 PM CDT Sun Apr 16 2017 ...UPDATE TO AVIATION... .SHORT TERM...(This evening through Monday) Issued at 345 PM CDT Sun Apr 16 2017 An area of showers and isolated thunderstorms moving through central Kansas in the vicinity of Hays this afternoon appears to be driven by some forcing mechanisms including weak mid level frontogenetic forcing, a 500 mb vort max and upward vertical motion associated with the right entrance region of an upper level speed max tracking out of the northern plains into the Midwest this afternoon. MRMS has occasionally hinted at some pea size hail with a few storms in this cluster but for the most part, think the biggest impact is brief moderate rain. This area of precipitation should move east of the Hays area later this afternoon. Later this afternoon and evening, attention turns to the potential for showers and thunderstorms to develop over the southeastern portions of the cwa. Surface analysis shows the frontal boundary extending from a weak low center over the northeast Texas Panhandle across northern Oklahoma into southeast Kansas this afternoon. There have been breaks in the stratus over south central Kansas and some surface heating has pushed temperatures into the upper 60s around Medicine Lodge. Latest SPC Mesoscale Analysis shows MLCAPE values around 500-1000 j/kg in south central Kansas with the highest CAPE farther south, along and south of the front. Models show scattered showers and thunderstorms developing later this afternoon generally to the south of a Liberal-Dodge City-Stafford line. The 18z HRRR has continued that trend and with simulated reflectivity progs keeping the intense storms farther south in western Oklahoma and the Texas Panhandle. For our area, will carry 30-40 pops in the southeast this evening. Will continue to mention the possibility of at least quarter sized hail in that area. Chances for storms should diminish later tonight. The other issue across southwest Kansas overnight will be fog potential. Given the moist upslope flow regime to the north of the front, would expect to see areas of fog developing. A few of the mesoscale models hint at widespread dense fog especially south of Highway 96 and west of Highway 283. Other Hi-Res models do not. Have added areas of fog to the southwest Kansas grids with patchy fog farther north and east over central and south central Kansas. Later shifts will need to monitor this for potential dense fog headlines. On Monday, the fog should thin out during the morning hours and the stratus will likely hang on through much of the day over many areas. This will make high temperature forecasts a little tricky. Will stay close to or a few degrees above MOS guidance over various locations. .LONG TERM...(Monday night through Sunday) Issued at 345 PM CDT Sun Apr 16 2017 Widely scattered showers and thunderstorms developing over the higher terrain of eastern Colorado on Monday evening could move out over western Kansas Monday night as a low level jet sets up. The increased low level advection will push warmer air back into western Kansas resulting in temperatures warming back into the 80s and possibly even low 90s on Tuesday and Wednesday. Another fast moving shortwave trough over the Dakotas and northern Nebraska will push a cold front south across Kansas Wednesday evening. The GFS and ECMWF break out showers and thunderstorms but keep it mainly over central and eastern Kansas. Behind the front, Thursday will be cooler with highs in the 60s. The medium range models continue to advertise a strong upper wave moving out over the Rockies and closing off into an upper low over Colorado and Kansas on Friday. This should bring significant chances for showers and thunderstorms to the region through Friday night before the system moves east of the area on Saturday. Given the strength of this system we could see the potential for a rain-snow mix or changeover to snow out along the Colorado border Friday night. Accumulation potential does not look great at this time but this will obviously have to be watched. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 608 PM CDT Sun Apr 16 2017 Prevailing low level stratus across much of central and southwest Kansas will lower tonight resulting in MVFR cigs initially this evening in the vicinity of all TAF sites. IFR cigs are expected to develop later tonight as the stratus layer continues to lower. A light easterly upslope flow and high relative humidity will create conditions favorable for fog development late tonight resulting in MVFR/IFR vsbys. East to northeast winds 5 to 15kt will persist through early Monday morning as surface high pressure remains across the Upper Midwest. Winds will then turn southeasterly 5 to 15kt mid to late Monday morning as the surface high pushes eastward into the Great Lakes. && .PRELIMINARY POINT TEMPS/POPS... DDC 51 70 56 83 / 20 10 20 0 GCK 49 69 54 85 / 10 10 10 0 EHA 50 69 53 86 / 20 10 20 0 LBL 53 69 55 86 / 20 10 20 0 HYS 48 71 57 80 / 10 10 30 10 P28 54 73 58 83 / 40 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Gerard LONG TERM...Gerard AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
934 PM CDT Sun Apr 16 2017 .UPDATE... /FFA ISSUANCE/ Convective initiation was handled relatively well by the HRRR which suggested some heavier rainfall to occur vs some of the coarser models. With this trend, the likelihood of a 5+ inch rain over western parts of the CWA increases, as we are meeting the 2 standard deviation pwat criteria for flood potential. Later tonight, a possible expansion of the watch may need to be considered should the ARW verify with a more progressive solution into northern counties. For now will expect the broad circulation seen in stratiform rain over the Serranias del Burros should delay this eastward expansion, and downdrafts to dictate a more slow eastward progression. Other meso model features suggest additional heavy rains entering the area from the north late Monday, so at some point, parts of Central TX will need to be considered at least for Monday. Low end severe weather remains a concern as well, given moderate values of CAPE and shear. && .PREV DISCUSSION... /ISSUED 749 PM CDT Sun Apr 16 2017/ UPDATE... /HIGHLIGHTING LOCALLY HEAVY RAIN...INCREASED POPS/ Radar echoes are increasing rapidly over western counties to suggest the more bullish storm scenario depicted by the last several HRRR runs. Given the earlier progress and location of convective initiation, felt the need to increase pops farther east for late tonight and boost overall QPF and mention locally heavy rainfall in the zones. These threats are already covered in the HWO. PREV DISCUSSION... /ISSUED 639 PM CDT Sun Apr 16 2017/ AVIATION... SHRA/TSRA are ongoing over the Big Bend to Serranias del Burro with weak SHRA over Central Texas due to an MCV drifting to the east. Will go with VCSH and tempo VCTS at KDRT this evening as a consensus of Hi-res models and radar trends continue show movement to the east with formation into an MCS. Have introduced VCSH at KAUS due radar trends for this evening. The western MCS will slowly weaken overnight encountering a capped environment. Redevelopment is expected Monday and maintain VCSH for the I-35 TAFs for the morning, then introduce VCTS for the afternoon hours as the cap erodes. VFR skies start this TAF cycle. CIGs lower to MVFR later this evening, then IFR as patchy BR and MVFR VSBYs develop overnight into morning. CIGS/VSBYs rise to VFR midday to afternoon. IFR/MVFR CIGs/VSBYs are possible in any SHRA/TSRA. MVFR CIGs return later Monday evening. S to SE winds 5 to 14 KTs will prevail. Gusts to 45 KTs are possible in TSRA downdrafts with gusts to 22 KTs possible elsewhere. PREV DISCUSSION... /ISSUED 337 PM CDT Sun Apr 16 2017/ SHORT TERM (Tonight through Monday Night)... Broken to overcast skies blanket most of South Central Texas this afternoon as a weak midlevel shortwave near Llano County continues to move northeast. Elevated echoes continue to show up on radar over the Hill Country associated with this feature, but these echoes have been evaporating before reaching the surface. Although weaker than this time yesterday afternoon, a relatively strong capping inversion just above 800 mb continues to show up on aircraft soundings at SAT and AUS. Most hi-res model trends continue to show that this cap will hold for the next several hours over the I-35 corridor, but a few notable outlier including the Texas Tech WRF indicate some storms may develop over the Hill Country and move southeast by 5-6 pm. These solutions seem a bit unrealistic given the movement of this shortwave and lack of any convective development aside from a brief cell that went up in Sutton County. Thus, the current forecast follows the broader model consensus and trends that this cap will hold for the I-35 corridor, with the best chances for any isolated thunderstorms confined to the Hill Country and Edwards Plateau this afternoon. Showers and thunderstorms continue to develop along a dryline in Big Bend and off the Serranias del Burros in Mexico as a stronger shortwave evident on WV imagery is providing some additional dynamic forcing via PVA and cooling aloft. There is quite a bit of model uncertainty in how these cells will organize and move to the east- southeast this evening, but it does appear that they will cross the border during the early evening hours and affect at least the Rio Grande Plains where 60 POPs have been added. Shear parameters continue to be rather unimpressive, but CAPE values peaking around 3000 J/kg just before sunrise and steep lapse rates aloft will support a marginal risk of some strong to severe thunderstorms early this evening in the Rio Grande Plains. Damaging winds will probably the main threats with these storms, but quarter to possibly golf ball size hail will be possible with multicellular clusters if this system does not become more linear before crossing the border. Most models are showing that the strength of the capping inversion and weakening dynamics from the shortwave will be enough to suppress convection tonight along and east of the I-35 corridor, but have maintained 20-30 POPs just in case a stronger cold pool develops to help propagate the system further east. Rain amounts should generally remain below one inch, but some locally higher amounts are possible in the Rio Grande Plains and Edwards Plateau that may cause isolated instances of flash flooding or (more likely) flood advisories. There will most likely be a brief lull late in the overnight hours and early tomorrow morning as a closed midlevel low or MCV left behind from tonight`s convection moves over the southern portion of South Central Texas. Cooling aloft with this feature should help weaken the cap at 800 mb enough to promote at least scattered if not widespread showers and thunderstorms by late morning and the afternoon. The best chances will be over the eastern two-thirds of the region as the western third should have NVA aloft on the backside of the low. Shear parameters still appear to be pretty weak, but moderate instability may support some strong to marginally severe storms, particularly across our southeastern-most counties. Rain chances will decrease by the evening hours, but have maintained 203- POPS over the entire region into Monday evening to account for a few model solution that suggest a complex north of our area will move to the south-southwest on the backside of the closed midlevel low later tomorrow afternoon and evening. LONG TERM (Tuesday through Sunday)... Rain chances will begin to decrease from west to east on Tuesday as the midlevel low or shear axis continues to weaken and slide to the east. However, this shear axis should be enough to support the development of isolated to scattered showers and thunderstorms along and east of Interstate 35 with the best chances in the Coastal Plains. A mid-to-upper level ridge will build in from the southwest on Wednesday and intensify further on Thursday to reestablish the capping inversion aloft and help increase temperatures into the mid 80 to lower 90s for the rest of the work week. Winds on Friday will strengthen ahead of a relatively strong front that both the GFS and ECMWF progress through our area Saturday morning or early afternoon. This should provide a good chance of showers and thunderstorms for at least the eastern half of our region, but models are beginning to suggest more dry slotting for the western half. The GFS suggests that below normal temperatures with dry conditions for at least a few days behind the front into early next week are looking more likely with continued northwest flow aloft, but the ECMWF has a weaker front with temperatures moderating more quickly. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 68 81 64 83 66 / 40 50 20 20 - Austin Bergstrom Intl Airport 68 80 64 82 65 / 30 40 20 20 - New Braunfels Muni Airport 68 80 64 82 66 / 40 50 20 20 10 Burnet Muni Airport 65 79 62 80 64 / 50 50 20 20 - Del Rio Intl Airport 65 82 65 85 67 / 70 20 30 10 - Georgetown Muni Airport 66 80 63 82 66 / 50 40 20 20 - Hondo Muni Airport 66 82 67 83 65 / 60 40 30 10 - San Marcos Muni Airport 68 81 64 82 66 / 40 50 20 20 10 La Grange - Fayette Regional 69 81 66 82 66 / 20 40 20 50 10 San Antonio Intl Airport 67 80 66 82 67 / 60 50 20 20 10 Stinson Muni Airport 68 80 67 82 67 / 50 50 20 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Monday morning for the following counties: Bandera...Dimmit...Edwards...Frio...Kerr...Kinney... Maverick...Medina...Real...Uvalde...Val Verde...Zavala. && $$ Mesoscale/Aviation...04 Synoptic/Grids...Oaks Public Service/Data Collection...YB
Area Forecast Discussion
National Weather Service Grand Forks ND
931 PM CDT Sun Apr 16 2017 .UPDATE... Issued at 931 PM CDT Sun Apr 16 2017 The clouds over the northern half of the FA are slowly expanding southward, so it appears that at least areas along and north of a line from Valley City to Fargo to Park Rapids will stay cloudy. These clouds may well expand even further southward, so will continue to monitor them. Other forecast elements are running on track. && .SHORT TERM...(This evening through Monday) Issued at 301 PM CDT Sun Apr 16 2017 One surface low is east of International Falls and the other surface low at mid aftn is closer to the 500 mb low and is just north of Winnipeg. A cold front wrapping south around this low as progressed through most of the forecast area with the cooler air at 925/850 mb lagging a bit. Core of the colder 925 mb airmass will move in once the low near Winnipeg moves a bit more east this evening. So will see a pretty good temp fall this evening most areas with overnight lows in the mid 20s to lower 30s north to south. Sunshine combined with some cooler air aloft producing 500 j/kg cape in NW MN and some spotty showers and even isolated lightning strike or two TVF-CKN-BJI area. These isolated showers will move east. Meanwhile did expand isolated shower chance farther west into NE ND as some weak echoes and sprinkles enter the DVL basin from the Minot area. Cloud cover is a main question for tonight into early Monday as upstream in Saskatchewan quite cloudy and feel most of the model blends try to clear things out a bit too soon. HRRR does keep high level of lower RH over the northern fcst area thru 12z. With the 500 mb system moving more east-southeast and not digging south the southern extent of thicker stratocu will likely stay north of Valley City-Fargo-Wadena. Clouds may be present to start Monday in the north and some concern it may take a while to clear out of far NW MN. Otherwise southwestern half of the fcst area should be fairly sunny before high clouds move in in the aftn ahd of next system. Highs Monday mid 40s north to mid 50s far south. .LONG TERM...(Monday night through Sunday) Issued at 301 PM CDT Sun Apr 16 2017 Low pressure tracking from northern high plains Mon night will move through central valley and toward MN arrowhead by Tue afternoon. Pcpn, now likely favoring northern half of area, should be mainly rain with a possible overnight/early morn mix along the northern tier/Devils Lake region. Mixed nature and short time frame should limit accumulations to an inch or so except maybe a couple of inches closer to Lake of the Woods. Some low elevated CAPE will track along and south of the sfc low, at this point FBR is void of thunder and will not include any at this time. Pcpn will end as rain by early afternoon along with below seasonal temps. The influence of Manitoba/Ontario high pressure Wed looks to result in a dry and marginally milder aftn. A couple of potentially closed lows (GFS) or swiftly moving open waves (ECMWF) heading through northern plains on Thursday will introduce the next risk of rain. Good guidance agreement is in place thereafter as a the week will end on a dry note lasting into the beginning of the weekend. High pressure anchored well north and east will initiate a drier southeast near sfc flow with temps into the 60s by Sat. . && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 703 PM CDT Sun Apr 16 2017 The gusty northwest winds will begin to decrease around sunset, with model guidance showing them becoming light by midnight in most areas. Then the attention shifts to clouds. Model guidance has been indicating clearing for most areas later tonight. However there is a lot of cloud cover along and north of highway 2 that does not appear like it will go away. Think this cloud cover will continue to sag southward and keep most areas cloudy tonight. Cloud heights in this area look to be mostly VFR, in the 4 to 5 thousand foot range. So will go with that idea into Monday and adjust as need be. && .FIRE WEATHER... Issued at 315 PM CDT Sun Apr 16 2017 Gusty westerly winds and especially dry conditions will continue across the southern FA through the late afternoon, with critically low relative humidities across far southeastern ND and much of west central MN. Expect winds to slowly diminish towards evening. And with cooling temperatures in the early evening, relative humidities should increase into the 30 to 40 percent range by 8 pm CDT, thus reducing the risk for extreme wildfire behavior in the later periods. && .HYDROLOGY... Issued at 315 PM CDT Sun Apr 16 2017 Moderate flooding continues at Neche. Next chance for significant precipitation is Mon night into Tue, where guidance indicates a reasonable chance for one quarter to one half inch of rainfall across the north. These projected amounts will be used in subsequent river forecasts which may alter the forecast traces. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Godon SHORT TERM...Riddle LONG TERM...WJB AVIATION...Godon FIRE WEATHER...Gust HYDROLOGY...WJB
Area Forecast Discussion
National Weather Service Fort Worth TX
825 PM CDT Sun Apr 16 2017 .UPDATE... Thunderstorms have remained either north or west of the CWA this evening and it looks like this will remain the case for much of the night. The exceptions may be along the Red River and our western-most counties, where explosive thunderstorm clusters may evolve into MCSs, possibly affecting these locations (well after midnight) as they slowly approach from the north and west. Have maintained chance POPs in these areas for the overnight hours, with a slight chance of showers (associated with a weak mid level disturbance overhead) for the rest of the forecast area. Better opportunities for showers and storms are still expected on Monday. 30 && .AVIATION... /ISSUED 659 PM CDT Sun Apr 16 2017/ Multiple mid level disturbances in the weak flow aloft are responsible for several areas of scattered convection this evening. A weak disturbance over Central Texas has helped to enhance seabreeze showers and storms to our southeast. A stronger disturbance is moving into the Southern Plains and should continue to generate storms across Oklahoma and Arkansas. A third feature over the southern Rockies has aided in the development of West Texas storms. All of this activity should remain far away from TAF sites this evening and overnight. That said, the Central Texas impulse may generate some showers overnight, hence the VCSH at 09Z in the Metroplex and 07Z at KACT. Conditions should remain VFR through late evening, then a layer of stratus will likely develop and spread northeast across the area after midnight. At this time it appears conditions will remain MVFR late tonight and early Monday, with a return to VFR early Monday afternoon. The remnants of what is expected to become an MCS over Oklahoma tonight will push south of the Red River Monday. A lingering outflow boundary may lead to isolated thunderstorm development during peak heating hours Monday afternoon, so VCTS has been added to all locations for 22Z and later. We will be able to better assess this potential as the event unfolds, and get a good meso-analysis on Monday. 30 && .PREV DISCUSSION... /ISSUED 318 PM CDT Sun Apr 16 2017/ A complex convective forecast is in store for North and Central Texas tonight through Monday, as several features will have some sort of role in mesoscale trends. We have been watching a very slow-moving shortwave/MCV feature over the Texas Hill Country all day long. This feature will continue its slow east-northeast trek across our Central Texas counties through the evening hours, before slowly exiting across East Texas and the Ark-La-Tex region after daybreak Monday morning. I will carry low, non-severe convective chances across mainly our southeast counties for this evening ahead of the MCV. Another feature in which isolated showers and storms have developed off of is an old undular bore type of boundary across Southwest Oklahoma/Northwest Texas that was an artifact from a decaying linear MCS early today over Eastern Oklahoma. In addition, a subtle shortwave was moving east along the I-40 corridor over the Northern Texas Panhandle. With the undular bore boundary focusing isolated strong to severe storms across far Southern Oklahoma, I have maintained slightly higher storm chances northwest of a Cisco-Jacksboro-Sherman line. Lastly, discrete storms had formed off the Davis Mountains in Far West Texas, just east of a weak surface low and surface dryline. Much further north, the dryline intersects a stalled synoptic surface front situated from Amarillo, Texas, to Woodward Oklahoma, to near Wichita, Kansas. The forecast overnight will be contingent on several things, both conducive and detrimental to convective initiation. The main foci for this period into Monday morning will be the old boundary and the synoptic stationary front much further north. As the subtle Texas Panhandle shortwave shifts east across Western Oklahoma overnight, the convection over Southern Oklahoma will shift east and weaken as in encounters relatively more stable air and capping from early Sunday morning storms over Eastern Oklahoma. Though this activity will likely weaken after dark, convection firing off the synoptic front further north and west across Northwest Texas/Northern Oklahoma will be increasing, with Corfidi vectors indicating a southeast motion across the state of Oklahoma and possibly into the Red River area around daybreak Monday. The WRF models, along with the HRRR are indicating a linear cluster of storms moving into North Texas early Monday morning, which could make for a stormy commute for those well north of the I-20/30 corridors. Other models such as the SREF and NAM/NAM Nest models were more conservative and delayed, possibly due to the aforementioned subsidence to the northwest of the Central Texas MCV and a more established elevated mixed layer (or cap) south of the Red River. I held the highest chances Monday across the northeast half of the CWA per the upwind corfidi vectors, as the convective system possibly gets cold pooled as low level wind fields weaken by daybreak Monday. An isolated strong to marginally severe storm can`t be ruled out, but for the most part think much of the activity will be of the general nature with lightning, small hail, and possible gusty winds the main risks. We`ll only see gusty winds if these storms do not become fully elevated. Scattered activity will continue to persist across much of the area, with the best chances east of I-35/35E. Convective rain chances will diminish quickly Monday evening, as the northern branch of shortwave energy exits to the northeast of the area. Another cut off shortwave disturbance over south-central Texas Monday night will likely keep better convective chances well south of our southern CWA. A dry period is expected Tuesday through early Thursday, as the area remains in between upper level systems with shortwave ridging overhead. Gusty south winds and humid conditions will be the rule this period with highs in the 80s, and possibly around 90 degrees across our far western counties. A weak cold front will push to the Red River Thursday and may result in isolated showers and storms across that area, but better upper forcing and winds will be further north and do not expect any significant activity with regards to a severe weather threat. For Friday into the coming weekend, medium range models still show (and in fairly good agreement) a vigorous system moving east out of Southern Colorado and Northern New Mexico out across the High Plains Friday. Better storm chances will remain relegated well north of the I-20 corridor during the day, before better large scale ascent and a surface cold front enter the region Friday night into Saturday morning at which time convective chances will dramatically increase. It`s hard to say how much of a severe weather threat will actually exist, as large-scale ascent will trail the surface front with much of the convection possibly anafrontal and elevated. With environmental and shear details a little blurry this far out, we will continue to fine tune forecasts in the coming days. We also suggest interests across our area follow forecasts and trends closely, especially if outdoor events are planned on Saturday. 05/emnant outflow boundary && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 66 82 64 86 65 / 10 50 20 5 0 Waco 65 81 64 84 64 / 10 50 20 20 0 Paris 64 79 62 83 62 / 30 50 30 20 0 Denton 65 81 63 85 63 / 20 40 20 5 0 McKinney 65 80 62 84 62 / 20 50 20 10 0 Dallas 67 82 65 85 66 / 10 50 20 5 0 Terrell 66 80 63 83 64 / 10 50 20 10 0 Corsicana 65 80 64 83 64 / 10 50 20 20 0 Temple 66 80 63 83 64 / 10 40 20 20 0 Mineral Wells 64 81 62 85 62 / 20 30 20 5 0 && .FWD WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service Hastings NE
644 PM CDT Sun Apr 16 2017 .SHORT TERM...(This evening through Monday) Issued at 332 PM CDT Sun Apr 16 2017 Mid level forcing associated with a weaker wave continues to bring precipitation to far southern portions of the CWA, with a few locations potentially picking up 0.10-0.20". The precipitation has been gradually sliding ESE, a trend that will continue the rest of this afternoon. At the surface, an area of high pressure continues to push east, with winds turning southeasterly with time. While sustained speeds have generally been around 10-15 MPH, gusts have been higher than expected, occasionally gusting to near 25 MPH. The precipitation/greater sky cover has kept temps in the 50s across the far south, with mid/upper 60s further north as of 3 PM. For this evening/overnight, kept PoPs out for this evening, thinking is that ongoing precip will push SE of the CWA by/near 00Z. Out to the west, models have been showing the potential for some scattered precipitation along an area of lower/mid level convergence to develop and move east. Kept the forecast dry, as these same models have activity diminishing before reaching western portions of the CWA, though some have it being a close call. Overnight lows in the lower 40s are expected. A weak surface pattern looks to bring light/variable winds later tonight across the area, but models showing the better fog potential remaining outside of the CWA to the WSW, so kept any mention out of the forecast. Will be a few things for the evening/overnight crew to monitor. Into tomorrow, the forecast remains dry, with upper level zonal flow in place and a lack of any notable disturbances. Winds turn more solidly to the SSE, as a sfc low/trough axis deepens along the High Plains. Sustained speeds near 15 MPH are expected, as are afternoon wind gusts near 25 MPH. Expecting partly cloudy skies, with highs reaching into the lower 70s. .LONG TERM...(Monday night through Sunday) Issued at 332 PM CDT Sun Apr 16 2017 The start of the long term period Monday evening remains dry, but precipitation chances will be working their way back into the forecast. After midnight Monday night and through the day on Tuesday, the area will be affected by an upper level disturbance crossing the Plains. The brunt of the better lift/precipitation chances are expected to be well north of the CWA across the Dakotas with the main low/better LLJ forcing, but lift trailing to the south crosses our area. Precipitation looks to start affecting western portions of the area around 09-12Z Tuesday, pushing east through the day, but models generally agree with better chances of scattered precip coming during the first half of the day. This disturbance pushes a weaker sfc boundary south through the area, with models showing it setting up over the southern half of the CWA by 00Z Wednesday. Highs for Tuesday look to top out in the lower/mid 70s. There may be a bit of a lull in precipitation at some point late Tuesday afternoon/evening as the area sits in between rounds of better lift, but with that frontal boundary meandering around, chances aren`t zero. During the evening/overnight hours Tuesday night/Wednesday morning, models are in good agreement showing the development of a 50+kt LLJ nosing in from the south, so expect coverage of shower/thunderstorm activity to increase across the area. The thunderstorm chances continue on in through the day/evening on Wednesday, though lift from the veering LLJ wanes, lift from a passing upper level disturbance increases. Models at this point are mainly affecting the northern half of the CWA, but the southern half bears worth watching as well. This disturbance will be pushing a reinforcing cold front through the CWA along with the sfc low, located roughly over the southeastern half during the late afternoon hours. One thing working against thunderstorm development along the front is the pretty warm mid level temps/capping models are showing. Shear/instability values during this timeframe lead to strong/severe thunderstorm concerns, and the area sits in the SPC Day 3 Marginal Risk area. This frontal boundary will make for an interesting temperature gradient across the CWA, the current forecast ranging from near 60 in the north to near 80 in the south. The current forecast for Thursday remains dry, with the area sitting under zonal flow between upper level disturbances. Forecast highs area in the mid 60s for most locations. Looks to be an unsettled end of the week, with an upper level low pressure system pushing through. Though the low crosses the Plains, there is some model uncertainty with its exact track, and if it tracks as far south as some show, it`s not going to have much of an impact on the CWA. Models are in pretty good agreement showing an overall lack of instability, so just have showers in the forecast. Will see how things trend in the coming days. Sunday is dry behind this system, with highs in the lower 60s after 50s for Fri/Sat. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday evening) Issued at 632 PM CDT Sun Apr 16 2017 VFR conditions are expected at both terminals through the period, but expect some fog development across Kansas to possibly creep towards KEAR early Monday morning. Evenso...with HRRR being the most aggressive with fog development, models are not brining the low stratus and fog quite that far north, so did not include a mention of any BR/FG at this time. Otherwise...expect southeasterly winds to continue to diminish at both TAF sites over the next couple of hours with light winds expected overnight. Early Monday morning...expect the pressure gradient to begin to tighten ahead of the next disturbance...with gusty southeasterly winds to 25 KTS or so expected by afternoon. && .GID WATCHES/WARNINGS/ADVISORIES... NE...None. KS...None. && $$ SHORT TERM...ADP LONG TERM...ADP AVIATION...Rossi
Area Forecast Discussion
National Weather Service Goodland KS
606 PM MDT Sun Apr 16 2017 .SHORT TERM...(This evening through Monday) Issued at 223 PM MDT Sun Apr 16 2017 Today and Tonight: Short range guidance is in good agreement about the formation of showers and thunderstorms this afternoon along a shortwave based boundary and CAPE axis (700 to 1500 J/Kg) located in eastern Colorado. The latest GOES satellite data is showing a cumulus field beginning to develop and grow along this boundary, leading to increased confidence in the feature. A second, more subtle boundary is stretched across the southeastern portions of the CWA. CAPE in this area is between 500 to 1000 J/Kg per the latest mesoanalysis and increasing gradually. SREF, RAP, and HRRR all indicate development in this area with the NAM keeping activity further east. Precipitation chances diminish after sunset with patchy fog after midnight across much of the CWA. Monday: Much of the day will remain dry through the early afternoon with a shortwave approaching during the middle to late afternoon. Thunderstorm chances increase after about 03Z from northwest to southeast as this feature traverses the CWA. A few strong to severe thunderstorms are possible as we head through the afternoon and into the evening hours. .LONG TERM...(Monday night through Sunday) Issued at 235 PM MDT Sun Apr 16 2017 Monday night-Wednesday night: West to southwest flow remains in place through these periods with main storm track well north of our CWA. Weaker shortwave troughs may interact with surface trough or weak fronts, and bring thunderstorm chances to the region. Lack of organized forcing lowers confidence overall, but there has bee a trend to show better support for possible scattered thunderstorm activity Monday evening and overnight. Regarding severe threat: Moderate instability may develop along surface trough axis by Monday evening with 0-6km effective shear in excess of 35 kt (generally linear based on profiles). High resolution guidance is showing several cells forming along the CO state line (near surface trough) moving east/merging. Forcing again isn`t great, so coverage could be a concern despite adequate instability. Isolated severe seems possible with hail/wind threats favored. I have even less confidence in thunderstorm coverage Tuesday through Wednesday night, but models do show instability increasing with quasi-stationary front near the NE border during these periods. If we see any thunderstorm activity there may be enough instability and shear that I couldn`t rule out a minimal severe threat (north) assuming anything develops in our area. Thursday-Saturday: During these periods the focus is on a stronger front and a strong trough expected to move across the Plains. Current 12Z has come into better alignment on general track (though there are still subtle differences). Specifically GFS/GEM have leaned towards the much more consistent ECMWF on a closed h7/h5 low developing over SW Kansas which could set the stage for a widespread beneficial precip event Friday through Saturday. Post frontal air mass will have limited instability (thunderstorms not favored), but there may be enough to support pockets of moderate to heavier precip. If the ECMWF is right we may see a mix of rain/snow on back side of upper low, but precip type at this range is always an adventure on a run-run basis. I was comfortable with higher PoPs blend gave me due to the better overlap in precip signal, and during the nighttime/morning period Friday night/Saturday I added rain/snow mix mention. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 529 PM MDT Sun Apr 16 2017 KGLD will start out VFR with lower IFR ceilings developing and spreading across the area after 06Z with visibilities also becoming IFR after 10Z. Conditions may occasionally become LIFR between 10-14Z. Visibilities will improve aver 15Z with a return to VFR conditions by 18Z and low ceilings dissipate. KMCK will start out VFR, but will not be affected by fog and low ceilings as much as GLD. MVFR conditions are possible between 11-18Z and will occasionally become IFR between 12-15Z before improving to VFR again by 18Z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ SHORT TERM...TL LONG TERM...DR AVIATION...LOCKHART
Area Forecast Discussion
National Weather Service Gray ME
913 PM EDT Sun Apr 16 2017 .SYNOPSIS... A cold front will cross the region tonight and a trough of low pressure will linger over the area on Monday. High pressure will build south from Canada Monday night and Tuesday and will shift east Tuesday night. Low pressure will weaken as it moves through southern Quebec on Wednesday and a trailing cold front will stall over the region Wednesday night. The front will lift north on Thursday ahead of low pressure moving east from the Great Lakes. Low pressure will slowly track east through the region Friday through Saturday. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... 915 pm Update: A few lingering showers in the mountains and along the midcoast areas otherwise all the showers have now exited east of the region. Have brushed up pops and temps based on latest mesonet data. 805 pm...a line of showers now about to exit to the east within the hour. Update based on latest POPS from radar. Used HRRR for extrapolation for rest of the evening. Input latest obs data to reflect current temps and trends for next few hours. No other changes attm. 535 pm Update: Based on latest radar based pops have made adjustments to timing of the line of showers/isold thunderstorms to move across fa. Made adjustments to grids for the rest of the afternoon into early evening for temps/dewpoints and RH based on input obs data. See Marine discussion section below for adjustments to SCA headlines for tonight. Previous Discussion: Cold front approaching from the west will sweep through the region early this evening bringing an end to summer-like weather. Line of convection getting organized at the eastern end of Lake Ontario and will be heading east through late afternoon. HRRR has a pretty good handle on this line and brings it into the Connecticut Valley around 500 pm. Expect this line to diminish as it continues east into eastern New Hampshire and western Maine early this evening. SPC not looking for anything severe in the CWA but damaging winds not out of the question in isolated strong cells and the situation will be monitored closely through the early evening. Behind the front expect clearing downwind of the mountains overnight. Clouds and occasional showers will persist overnight in the north. Lows will bottom out in the 40s north and 50s south. && .SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/... A trough of low pressure will linger over the region on Monday keeping clouds and occasional showers going in the mountains. Farther south...a mix of sun and clouds will prevail in a blustery northwest flow. Highs will range from the mid 40s to mid 50s north and will range through the 60s south. Clouds and rain or snow showers will persist in the mountains Monday night and the remainder of the region will see variable clouds as an upper trough swings through northern New England. Lows will range from the mid 20s to mid 30s north and mid to upper 30s south. && .LONG TERM /TUESDAY THROUGH SUNDAY/... High Impact Weather Potential: Low potential for some wet snow accumulations in the Wednesday night through Thursday night period in the mountains. However...confidence is low. Pattern: A look at the flow pattern across North America early this afternoon reveals a large scale southwest to northeast orientation...due to large scale ridging over the southeastern United States...with unorganized troughing off the west coast of North America. This is helping fuel today/s warmth...with little blocking allowing fast moving systems to race across the country. A bit of a change is in the works through this long term forecast period as the combination of cutoff low development over the western Atlantic combines with developing ridging along the US West coast to cause the flow to reorient to more of a WNW/ESE direction...pushing more significant warmth to our south and eventually...towards /and beyond/ the very end of this forecast period...slowing the pattern down a bit. With the jet aloft cutting across the CONUS for much of the week...expect a series of impulses to maintain unsettled conditions after initial high pressure on Tuesday pushes east. Another respite is possible as we reach next weekend...although /as discussed below/ confidence is shaky at this point. Model trends/confidence: Spread in the deterministic/ensemble guidance occurs rather quickly this coming week...which is not surprising with a spring-like pattern featuring a number of cutoffs which frequently cause predictability issues. GEFS RMOP graphics agree and paint a similar story to a comparison of deterministic runs...showing good guidance agreement through Wednesday...with rather large differences between guidance sources beyond this...through the end of the forecast period on Sunday. Confidence is thus high through the arrival of shortwave number one on Wednesday...with confidence falling below average beyond this /although unsettled late week conditions are generally agreed upon/ with confidence falling further for next weekend. The Details.... Tuesday: High pressure settles in over Atlantic Canada well north and east of New England. This feature should continue to build south over our area during the day...but there has been a weak signal for days that a lingering inverted trough Monday night will leave some residual llevel moisture that may combined with the easterly flow associated with the high to produce low clouds and even a chance of drizzle all trapped beneath strengthening subsidence inversion. There has been a trend to a more northeasterly /vs southeasterly/ flow at the surface over the past 2 days which would provide less support to maintaining the low level moisture. Will keep PoPs out of the forecast and begin the day with low clouds that will break up with time as the deeper moisture thins and is pushed west. With an onshore component to the expect a rather cool day with mid 40s to lower 50s /east to west/ being about all we can do. Wednesday-Wednesday Night: We have seen increasing agreement that next arriving low pressure system will be in a weakening phase as it hits amplifying downstream ridge...with warm advection precipitation arriving Wednesday afternoon. Trends have favored this system being weaker...with a less impressive moisture plume. This all suggests a fairly unimpressive precip-maker. Given the time of arrival...will probably see all rain although temperatures will be marginal in the mountains. No doubt a chilly day with highs stuck in the 40s over most spots...with some lower 50s over southern NH and near the CT valley. Expect showers to continue into Wednesday night...with some snow potentially mixing in over the mountains...but no significant impacts expected. Thursday-Friday: A bit of a lull arrives Thursday as weakening shortwave continues to head east of the region. Cold front will stall south of the region...but remain a bit too close for comfort to keep the forecast dry with a few rain showers possible and another day of cool temperatures likely. Run to run and model to model inconsistencies loom large for the next arriving shortwave for Thursday night and Friday. The GFS/GGEM are much more amplified with the wave...but lack support from many GEFS members. The ECMWF is much less amplified...with a secondary wave that becomes dominant with time. These differences are important as the EC and many EC-EPS members take surface low pressure south of New England...allowing cool air associated with Canadian high pressure north of the region to filter south...bringing ptype questions into play. What is likely is another precipitation event. As for ptype...given poor confidence...will paint a chance for rain/snow in the mountains on Friday...with this mix potentially reaching further south particularly Thursday night. Again...high temperatures will remain least 10F below seasonal norms. Saturday-Sunday: There is weak agreement that low pressure will push east of the region for next weekend...with the level of drying and cooling behind this system in question. The overall pattern re- orientation certainly favors highs below climatology on Saturday... with less reason to depart from climatology for Sunday. Precipitation chances likely higher in the mountains /again giving a nod to climatology/ but no higher than slight or low chance given the drying trend portrayed in both the deterministic and ensemble suites. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... Short Term...MVFR/IFR ceilings in the mountains tonight with MVFR ceilings Monday through Monday night. VFR south Tonight through Monday night. Long Term...Threat for MVFR stratus Tuesday morning with improvement during the day continuing through Wednesday morning. Arriving low pressure on Wednesday and Wednesday night will bring a period of MVFR/IFR in SHRA with lingering clouds...showers...and possibly drizzle and fog continuing restrictions through Thursday. Another low pressure system will likely maintain poor flying conditions to end the week Friday. && .MARINE... Short Term...Continuing SCA`s through tonight over the outer waters and allowing the SCA to expire at 8 pm in the bays. Gusty west to southwest winds will subside in the bays this evening but continue for a while over the outer waters...also seas will remain near 5 ft over the outer waters through much of the night so continued the SCA for those areas. Long Term...Headline free conditions are generally expected Tuesday-Tuesday night. Southeasterly winds ahead of low pressure on Wednesday will likely bring a period of SCAs through early Thursday. Uncertainty beyond this precludes much detail...but SCAs are again possible to end the week Friday. && .FIRE WEATHER... Relative humidities will drop to between 30 and 35 percent across portions of southern New Hampshire and southwest Maine Monday afternoon. Although most areas will see some rain overnight...winds will be strong and gusty on Monday and with the low RH burning should be discouraged. && .HYDROLOGY... Record breaking warmth today caused significant melting of snow causing rivers to rise and some minor flooding along a few of them. Several river flood warnings have been issued this evening. Only minor flooding is expected. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory until 8 AM EDT Monday for ANZ150-152. Small Craft Advisory until 2 AM EDT Monday for ANZ154. && $$
Area Forecast Discussion
National Weather Service North Platte NE
618 PM CDT Sun Apr 16 2017 .SHORT TERM...(This evening through Monday) Issued at 302 PM CDT Sun Apr 16 2017 A slight chance for high based showers and thunderstorms this evening across the southeast panhandle eastward to near Thedford and Imperial. By late evening through midnight, lingering showers over the area still possible. In fact, the rapid refresh and rap models show showers possible into the early morning hours in west central Nebraska. The focus will be near and east of a weak cold front sagging southeast over the northwest forecast area. Very little rainfall with any of the thunderstorms this evening, and any lightning strikes could spark a grassfire which will need to be monitored. Mid level moisture with a modest return of gulf moisture on Monday will bring increased instability to the eastern panhandle and western Sandhills. An upper level trough will move into the Northern and Central Plains Monday afternoon. With steep mid level lapse rates 7.5-8.0 c/km and sbcapes 500-800 j/kg a 20-30 percent chance for thunderstorms near and west of highway 61. .LONG TERM...(Monday night through Sunday) Issued at 302 PM CDT Sun Apr 16 2017 Thunderstorms chances are from 30 to 40 percent across north central and central Nebraska Monday night, with a slight chance west central and southwest. Instability is rather weak at 200-500 j/kg, and actually weakens overnight. With H5 height falls confined to the Dakotas, and a 40 kt low level jet pointed toward the leeside of the Black Hills and south central South Dakota, the best focus will remain north of the area. A few high based storms could produce marginally severe hail/wind gusts west of Valentine to Oshkosh until 03Z, with weakening convection expected overnight. Another upper trough approaches the area Tuesday night providing a better chance for showers and thunderstorms. Increased instability and 0-3km shear from 30-45 kts sufficient for strong storms across southwest and central Nebraska overnight. As the upper trough crosses the area on Wednesday, showers and a few thunderstorms remain likely across north central and central Nebraska. Chances decrease or end across southwest Nebraska in the afternoon. An upper trough will dig across the Pacific Northwest Thursday, and close off over Colorado on Friday. This southeastward tracking system will provide better chances for showers to the southwestern half of the forecast area Thursday night through Friday night, while most of the northeast may remain dry. Aside from a slight chance for morning showers Saturday, the remainder of the weekend looks dry. Highs remain above normal in the 70s Tuesday. Forecast highs on Wednesday contrast from 55 to 60 north, to near 70 south. Temperatures cool to the mid and upper 50s by Friday and Saturday, influenced by the upper trough and Canadian high pressure across the region. By Sunday, upper ridge on the backside of the trough will bring warmer highs in the 60s to western Nebraska. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 618 PM CDT Sun Apr 16 2017 For the KLBF terminal: Expect scattered to broken ceilings ranging from 8000 to 12000 FT AGL into the overnight hours. Ceilings will lower to around 3000 FT AGL by sunrise Monday and will persist through late morning Monday. Scattered high clouds AON 20000 FT AGL are expected for Monday afternoon. For the KVTN terminal: Expect overcast skies into the mid evening hours with some clearing expected overnight. There is a small threat for light rain showers through this time. Ceilings this evening will scatter out and increase to 20000 FT AGL agl through Monday afternoon. Clouds will increase further Monday afternoon with ceilings falling to 6000 to 10000 FT AGL. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Buttler
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
707 PM CDT Sun Apr 16 2017 .SHORT TERM... (Through Late Monday Afternoon) Issued at 334 PM CDT Sun Apr 16 2017 Primary concern for tonight and Monday is thunderstorm chances. Guidance is showing another complex of thunderstorms tonight, developing somewhere between Oklahoma City and Springfield Missouri. This obviously covers a lot of real estate...and the key for precip chances in our area will be how far north the storms develop. The RAP mass fields support a more solution to the high sliding in across northern Missouri, and this fits my conceptual model of how this might evolve better than most other guidance. However, most of the convection allowing models like the HRRR, and WRF develop the thunderstorms further north which affect most areas along and south of I-70. Can`t ignore the CAMs in good conscience, so have kept mention of storms in along and south of I-70 after midnight and into Monday morning with likely PoPs across the eastern Ozarks by around 12Z. Think any lingering showers or storms should be exiting the area by late afternoon. Temperatures will once again be very dependent on where precipitation falls...but am leaning once again toward the warmer MAV guidance. Carney .LONG TERM... (Monday Night through Next Sunday) Issued at 334 PM CDT Sun Apr 16 2017 Still looks like an active week as global models are showing a transition from quasi-zonal upper flow at mid-week to more amplified flow by next weekend. ECMWF/GFS/Canadian still show two shortwave troughs moving across the area during the workweek. As is often the case with zonal flow, there are slight differences in the timing and strength of the shortwaves today compared to yesterday. Consequently have low confidence in the timing of precipitation from midweek on. It now appears that the first shortwave will stay north of the area on Tuesday causing the attendant cold front only to move as far south as northern Missouri and central Illinois. Then the next shortwave will move into the Midwest by Wednesday night and Thursday which will help push that front southeast through the area on Thursday. It does appear that we will spend more time in the warm sector in between the the two storm systems. Monday night into Tuesday looks mostly dry as a shortwave ridge moves across the area. Then the chance of showers and thunderstorms will be mainly concentrated over the northern half of the CWA Tuesday into Wednesday night close to where the cold front will be stalled. Still have a chance of showers and thunderstorms going across the entire area on Thursday as the cold front moves through. The global models have come into better agreement next weekend in showing a large upper low moving out of the southwest CONUS into the the Midwest by next weekend. There is still some uncertainty with the exact track of the surface low with this storm system, but it does appear that we will get showers and some thunderstorms with this system. Temperatures this week will continue to be above normal in the warm sector with 850mb temperatures in the 10-15C range. Then near or just below normal temperatures will move into the area behind the cold front. Britt && .AVIATION... (For the 00z TAFs through 00z Monday Evening) Issued at 651 PM CDT Sun Apr 16 2017 Specifics for KUIN: VFR through the period. A thunderstorm complex is expected to develop overnight, but it should remain south of KUIN. Northerly winds will gradually veer and become northeasterly to easterly by the end of the valid TAF period. Specifics for KCOU: The greatest uncertainty during the first 0-12 hours concerns the northward extent of a nocturnal thunderstorm complex which is expected to develop overnight. It`s unclear whether the complex will affect KCOU. Northerly winds will gradually veer and become northeasterly to easterly by the end of the valid TAF period. Specifics for KSTL, KSUS, KCPS: A line of showers developed just to the south of the St. Louis metro area terminals prior to TAF issuance. These showers are expected to continue moving away from the terminals and may dissipate after sunset. The greatest uncertainty during the first 0-12 hours concerns the northward extent of a nocturnal thunderstorm complex which is expected to develop overnight. It`s unclear whether the complex will affect the St. Louis metro area TAF sites. Northerly winds will gradually veer and become northeasterly to easterly by the end of the valid TAF period. Kanofsky && .LSX WATCHES/WARNINGS/ADVISORIES... MO...None. IL...None. && $$ WFO LSX
Area Forecast Discussion
National Weather Service Memphis TN
915 PM CDT Sun Apr 16 2017 .DISCUSSION...Surface analysis this evening places a weak cold front over Southern Illinois, Missouri, and Northern Oklahoma. WSR-88D radar trends have shown isolated showers and thunderstorms over portions of far Northwest Tennessee over the past couple of hours with the remainder of the forecast area mainly rain free. Latest 00Z WRF along with the latest HRRR run suggest rain potential will remain isolated at best for the remainder of tonight except for portions of Northeast Arkansas. Will make some slight adjustments to rain chances and any other elements as needed for the remainder of tonight. CJC && .PREV DISCUSSION... /issued 713 PM CDT Sun Apr 16 2017/ UPDATE...reduced rain chances down to isolated coverage as best potential for showers and thunderstorms across the forecast area, especially north of I-40 will be late tonight towards sunrise. No other changes made at this time as remainder of forecast is in good shape overall. CJC PREV DISCUSSION... /issued 625 PM CDT Sun Apr 16 2017/ UPDATE... Updated to include the 00z aviation discussion. PREV DISCUSSION... /issued 314 PM CDT Sun Apr 16 2017/ DISCUSSION... Currently...The outflow from this morning`s MCS is pushing into northern sections of the Mid-South. Most of the thunderstorms assoicated with this feature are located to the north of the Mid- South over SE Missouri and Western Kentucky for now. Isolated to scattered showers and thunderstorms also stretch from North Mississippi into parts of West Tennessee. This corridor has been a favored spot for development throughout the day. That corridor seems to be a little more unstable with SBCAPES from 1500-2000 j/kg. Temps are in the upper 70s to lower 80s across the Mid-South. Tonight...The outflow boundary will continue to push across the northern counties which could produce additional activity this evening. Kept the highest pops during the evening toward NW Tennessee. Later tonight a mid level shortwave will trigger another MCS across NW Oklahoma and NW Arkansas. Some of this activity could reach Northeast Arkansas by daybreak. Temps will be mild overnight with lows in the 60-65 degrees range. Monday...A cold front will sag into the area while a mid level shortwave moves into the region. An MCS should be moving into the region during the morning hours probably weakening by later in the morning with additional activity in the afternoon along any outflows that are created. Lack of wind shear across the region should help keep severe chances down. Temps will range from the lower 70s north to 80 south. Monday night through Wednesday night...Front will stall over the region and gradually dissipate. Meanwhile a mid level trough will slowly edge east. Better chances for showers and thunderstorms will shift south and will be maximized during the afternoon and early evening. Above normal temperatures will continue. Thursday into the weekend...A cold front will push into the region on with chances for showers and thunderstorms toward the end of the week. A more significant system is on tap for the weekend as an upper low develops over the Southern Plains and tracks into the Mississippi Valley. Models are showing a variety of solutions ranging from rain to perhaps some severe weather over parts of the area Saturday and Saturday night depending on the track of the system. After the system moves through we will shift to some below normal temps for a couple of days. SJM && .AVIATION... /00z TAFs/ VFR conditions prevail across the Mid-South this evening with only a few showers scattered across the CWA. Generally dry (and VFR conditions) will continue most of the night, but we do anticipate an increase in shower coverage after 08z with patchy MVFR ceilings. A surface boundary will sag south into the area on Monday, providing a focus for showers and thunderstorms throughout the day. Thunder was included in the vicinity of KJBR after 15z, reaching KMEM by early afternoon. There may be tempo restrictions to visibility in an around convection with ceilings in the ballpark of 2500-3500 ft much of the day. Winds will be from the south and southwest at less than 10 kts, shifting to the east and northeast behind the surface boundary. Johnson && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Miami FL
805 PM EDT Sun Apr 16 2017 .AVIATION...VCSH for KAPF to start with ongoing seabreeze convergence activity diminishing after 02Z. Isold Atlc SHRA will continue to affect east coast. Coverage increases after 12Z with another moisture surge, with best chances shifting inland after 16Z along with potential for isold TSRA. TEMPO MVFR with any activity through period. East coast sites will see speeds diminish to 9-14kts after 02Z with KAPF becoming ENE 5-8kts as seabreeze diminishes. Winds increase out of ESE after 14Z to 10-15kts, with late day Gulf breeze at KAPF. && .UPDATE... IR satellite loop shows a swatch of moisture laden strato cu west of Andros Island moving slowly to the northwest. This surge of moisture will the main player in our weather for late tonight and into early Monday morning. Current radar trends indicate light to moderate showers moving westward along the Gulf Coast metro region, near Marco Island and Naples. Short term models, including the HRRR and Hi- Res WRF prog this activity to dissipate and move offshore during the next several hours. However, by early Monday morning, shower activity begin to increase from south to north, due to the previously mentioned feature. Have increased PoPs to Chance category along the SE fringes of our CWA during this time frame. Otherwise, all other variables appeared on track. && .PREV DISCUSSION... /issued 425 PM EDT Sun Apr 16 2017/ DISCUSSION... Through Tuesday night: Latest surface analysis continues to indicate a strong 1029 mb surface high positioned a few hundred miles west of Bermuda. Tight surface pressure gradients generated from this feature have allowed breezy easterly winds to persist today over South Florida. These winds have mainly been sustained 10-20 mph with the occasional gust to 25 mph, slightly weaker than 24-hours prior. Streamer showers, originating from the Bahamas, continue to move east to west across the Atlantic waters and over the east coast metro region. The MFL 12Z morning ROAB sounding showed sufficient lower level moisture from the surface to around 800 mb, then dry air in the mid levels, consistent with the mainly light activity moving onshore. Tonight, as the aforementioned surface high proceeds to elongate and weaken, east winds will begin to decrease. As for precip, the HRRR and Hi-Res WRF show spotty, mainly light, showers propagating over the peninsula through the early morning, but nothing of great significance. Tomorrow, as the surface high further weakens, flow will turn east southeast. With this flow regime in place, deeper moisture will be allowed to edge slowly northward over South Florida. The 12Z GFS indicates PWAT values rising to nearly 1.5 inches by Monday afternoon. Increased moisture combined with weak instability, forecast SB CAPE near 500 J/KG and LI down to -1 or -2C, will lead to increased showers and activity with a slight chance of thunderstorms. However, not expecting any organized or strong convection, due to the unimpressive instability parameters. On Tuesday, east southeast flow will continue, lending to highest chance of precip over the western interior portion of the peninsula. Maximum temperatures both Monday and Tuesday are forecast in the low 80s, typical for this time of year. Wednesday through Sunday: The overall pattern will remain unchanged with surface high pressure sitting stagnant near Bermuda. Expect southeast flow with occasional showers, generally nighttime activity along the east coast and interior during the afternoons. Both the GFS and ECMWF have backed off on the amount of moisture advected into the region, thus coverage should be less widespread than on Monday or Tuesday. The next, more significant, chance of showers and storms comes late in the weekend, as a cold front approaches from the west. Forecast maximum temperatures are in the low 80s through the period, again within a degree or two of average for this time of year. MARINE...Marine conditions will continue improve through early next week, as the small craft advisory over the Atlantic was allowed to expire. However, small craft will still need to exercise caution for winds around 15 knots, especially over the offshore Atlantic waters. Widely scattered showers will be possible over the next several days, with a few thunderstorms also possible on Monday. BEACH FORECAST...A High Risk of rip currents will continue for the Atlantic beaches through at least Monday with brisk onshore flow. Rip current risk may decrease slightly heading into the middle of the week with weakening east south east flow, but likely remain at least at a moderate risk. && .PRELIMINARY POINT TEMPS/POPS... West Palm Beach 71 82 69 81 / 20 30 20 20 Fort Lauderdale 72 81 71 81 / 20 40 20 20 Miami 71 82 70 82 / 20 40 20 20 Naples 66 84 66 83 / 20 40 20 30 && .MFL WATCHES/WARNINGS/ADVISORIES... FL...High Rip Current Risk through Monday evening for FLZ168-172-173. AM...None. GM...None. && UPDATE...27/JT DISCUSSION...27/JT MARINE...27/JT AVIATION...88/ALM BEACH FORECAST...27/JT
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1052 PM CDT Sun Apr 16 2017 .Updated for 06Z Aviation Discussion... Issued at 1047 PM CDT Sun Apr 16 2017 && .SHORT TERM...(This evening through Monday) Issued at 245 PM CDT Sun Apr 16 2017 A pair of upper lows this afternoon could be found along the international border, with steep mid-level lapse rates resulting in scattered shower development in northern MN, though this activity is expected to remain north of us as the cool mid level temps driving this instability reaches our NE CWA this evening, after we lose diurnal heating. What these upper lows will do is send a dry cold front across our area tonight. This front at 3 pm was stretched out from near International Falls back west to across southern NODAK between I-94 and SODAK. This front will allow winds to become more NW/N tonight and Monday. For precip chances, removed the sprinkle mention we had, with dry low level air looking to best any attempt at precip generation. The best chance for sprinkles/light rain though looks to go down along the I-90 corridor. This is where the RAP shows a band of FGEN in the h7-h6 layer traversing, with the HRRR and 3 of the 4 HopWRF members showing some light returns developing around midnight. Again, soundings show air below h85 remaining dry, so this looks to be nothing more than a layer of broken to overcast clouds in the 8k-10k foot layer. As for temepratures, we will see cooler air filter in behind the front overnight. Mixing to h85 on the GFS shows our entire are remaining below 60 for highs Monday, with model blends coming in a few degrees cooler for highs tomorrow as well. For highs, split the difference between the cooler 12z guidance and the warmer going forecast, which knocked highs for Monday back a couple of degrees. We`ll have pretty much full sunshine tomorrow, so we should be able to warm a bit more than what the blended guidance has. .LONG TERM...(Monday night through Sunday) Issued at 245 PM CDT Sun Apr 16 2017 The long term will feature two systems, one early Tuesday and the other late Wednesday into Thursday. A gradual warm up will follow into next weekend. Models are in good agreement with timing and intensity of a band of showers moving through late monday night into Tuesday morning. Instability is minimal with poor lapse rates in place, but moisture transport is impressive with the 55-65 kt LLJ overhead which could bring some isolated thunder. The rain should move into WI by early afternoon and out of the area by late afternoon. Dry slot moving in behind the rain with gusty southwest winds will allow temperatures to quickly rebound into the 60s. A narrow corridor from south central to east central MN could reach the lower 70s given a favorable placement of the thermal ridge during mid afternoon. Cold front will push through during the afternoon with the next system already taking shape over eastern CO/western KS. Heavy convection will likely be ongoing along the front Tuesday night along or south of the I-80 corridor. The front may not be able to lift back north of that Wednesday, which means the system will track well south of the CWA. Models have generally shifted south with this system which is not all that unusual given the aforementioned setup. Nonetheless, southern MN is likely to see widespread rain Wednesday afternoon and Wednesday night, it`s just a question of how far north the rain shield will lift. PoPs trend downward pretty quick with northern extent across central MN and northwest WI during this period. Surface ridging will build south and should keep seasonal temperatures in the area for late week. A warming trend is probable ahead of a series of fronts late weekend into early the following week. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1047 PM CDT Sun Apr 16 2017 VFR conditions throughout. Clouds with bases around 10kft will pass overhead. Light northwest winds will become calm on Monday and eventually take on a southeasterly direction late Monday ahead of the next system that will spread rain across the region early Tuesday morning. KMSP... VFR conditions throughout. Precip chances will return around 12Z on Tuesday, but did not include mention in the taf for this issuance. /OUTLOOK FOR KMSP/ Tue...MVFR and -RA with IFR/TSRA possible in morning. Wind SSW bcmg W in afternoon at 10G20kt with dry conditions. Wed...VFR with -RA/MVFR Cigs likely overnight. Wind NE at 10G15kt. Thu...MVFR Cigs possible early then VFR. Wind NE at 5-10kt. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...MPG LONG TERM...BORGHOFF AVIATION...JRB
Area Forecast Discussion
National Weather Service San Francisco Bay Area
847 PM PDT Sun Apr 16 2017 .SYNOPSIS...Periods of light rain will continue overnight, mainly across the southern portion of our region. An unsettled weather pattern is then likely to continue through the first half of the week, with periodic chances of light rain. Dry weather, along with a warming trend, is forecast late in the week and into next weekend as high pressure builds over the region. && .DISCUSSION...As of 8:45 PM PDT Sunday...A spring frontal system produced widespread light rain across our region today. Rainfall amounts were mostly between a tenth and a half inch, although a few locations in Sonoma County and Santa Cruz County accumulated more than a half inch. The frontal rain band moved off to the east and south of our area early this evening. However, a moist west-southwest flow continues behind the front and is resulting in patchy very light rain at the present time. According to the lastest NAM and HRRR models, spotty very light precipitation will continue overnight and into early Monday morning, mainly from Santa Cruz and Santa Clara Counties southward. A broad upper trough is forecast to remain positioned off the West Coast through the middle of the week. Weak disturbances moving through the trough will interact with moist WSW flow and continue to produce periods of light rain across our region. Rain chances will be highest from Monday evening through Tuesday morning. Additional rainfall through midweek is generally expected to be a half inch or less, although some locations in the coastal hills could see an inch or more. The upper trough will finally move eastward on Wednesday and then inland on Wednesday night, allowing dry weather to return by Thursday. Dry and warmer weather is then expected late in the week and into next weekend as an upper ridge develops over California. && of 4:30 PM PDT Sunday...Frontal system has passed through the MRY Bay Area. The moisture has allowed cigs to lower to MVFR in many places. Showers will start to diminish after 06Z with cigs improving. Chance for showers Monday afternoon due to convective heating. Vicinity of KSFO...MVFR with showers through 06Z then becoming VFR. Southeast winds 8-12 kt decreasing after 06Z. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...Areas of MVFR/IFR cigs with showers through 10Z. && of 4:30 PM PDT Sunday...Southerly winds will remain gusty this afternoon and evening as a low pressure system moves east over the Pacific Northwest by this evening. Winds will decrease tonight as the low continues to weaken. High pressure will build over northern California Tuesday. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...SF Bay until 10 PM SCA...Mry Bay until 10 PM SCA...Pt Arena to Pt Reyes 0-10 nm until 10 PM SCA...Pt Reyes to Pigeon Pt 0-10 nm until 10 PM SCA...Pigeon Pt to Pt Pinos 0-10 nm until 10 PM SCA...Pt Arena to Pigeon Pt 10-60 nm until 10 PM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm until 10 PM SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM && $$ PUBLIC FORECAST: Dykema AVIATION: W Pi MARINE: Sims Visit us at Follow us on Facebook, twitter, and youtube at:
Area Forecast Discussion
National Weather Service Norman OK
916 PM CDT Sun Apr 16 2017 .DISCUSSION... Scattered storms over northern and western Oklahoma are expected to slowly diminish, but not completely disappear. Storms from the Texas panhandle are not likely to move as far east as western Oklahoma. The forecast was significantly updated to account for an anticipated MCS that the HRRR has consistently forecast for central and southeast Oklahoma around and beyond sunrise Monday. Pops were adjusted through noon Monday. && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 76 58 75 59 / 40 60 60 20 Hobart OK 78 59 76 57 / 40 60 20 20 Wichita Falls TX 80 61 80 60 / 30 50 30 20 Gage OK 74 55 74 55 / 30 50 20 20 Ponca City OK 78 56 75 58 / 90 70 30 20 Durant OK 79 62 78 60 / 40 50 60 20 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ 99/99
Area Forecast Discussion
National Weather Service Blacksburg VA
841 PM EDT Sun Apr 16 2017 .SYNOPSIS... A warm southwest flow of air will prevail across the region overnight ahead of a cold front approaching from the northwest. This front will drift southeast into the area late tonight into Monday, before stalling in North Carolina on Tuesday and Wednesday. && .NEAR TERM /THROUGH MONDAY/... As of 835 PM EDT Sunday... Band of showers and storms associated with a residual outflow boundary and weak surface trough has all but faded upon pushing into eastern sections after loss of heating. Expect once this shallow convection dissipates shortly, will see a brief period of weak subsidence and even some clearing/drying well in advance of the main upstream pre-frontal convection still back along the Ohio River per latest IR loop. Latest HRRR and other solutions suggest any of this frontal shower coverage wont reach the far northwest until after midnight, and perhaps may take until almost daybreak for a more widespread band of showers to reach the west/northwest given a weak wave along the front. Therefore have trimmed back pops for the rest of the evening/overnight with a gradual increase along the I-64 corridor after midnight, with highest pops around 12z into midday Monday for now. Otherwise looking at mainly partly cloudy skies for the most part tonight with lows tweaking down a bit more into the 50s given more clearing early on. Previous updated as of 727 PM EDT Sunday... Coverage of showers up until just recently has remained isolated to widely scattered. However, deeper convective development has recently occurred in the Southside of Virginia southward to the North Carolina foothills. I`ve essentially nowcasted this band of showers and isolated embedded thunder as these will drift east and are apt to steadily weaken with loss of insolation. Used a heavy blend of the most recent higher-resolution guidance trends for PoPs/Wx for the mid-evening and overnight period. More organized sub-severe convection is taking place way back to the west into central KY and eastern Ohio associated with frontal trough, and slightly steeper mid-level lapse rates/elevated instability reflected in about 500-1000 J/kg of MUCAPE. Confined any isolated to scattered showers/storms to the Mountain Empire and into western sections of Mercer, Summers and Greenbrier Counties until about 2 am. PoPs then increase and slightly build eastward into the pre-dawn hours as frontal trough approaches our far western zones. Though I couldn`t rule out a rumble of thunder overnight, should be the exception vs the rule with ongoing clusters of storms to our west likely in a significantly diminished state by early morning. No significant changes made otherwise. Previous near-term discussion issued at 300 PM follows... In the synoptic scale a broad ridge is centered over the western Atlantic and has brought very warm and fairly moist air to the region today with dewpoint in the 50s. The upper flow is quite zonal from the western Great Plains to the eastern seaboard and will remain so the next 24 hours. Showers and a few thunderstorms that have persisted much of the day across eastern KY and parts of OH/WV have been slow to advance eastward but may brush the western counties late this afternoon. A few popup storms or showers are still possible further east with chance are slight. Severe parameters are unimpressive and any storms should be pulse-type of short duration. Will see a decrease in shower coverage this evening before a frontal boundary begins to sink southward from the upper Ohio Valley into the the northern part of the forecast area by early Monday and will drop slowly south to about the NC-VA border by Monday evening. Forecast movement of this feature is somewhat slower than previous runs but not drastically different. Will see more clouds with this feature along with increasing chances for rainfall. Modest QPF in the 0.10 to 0.25 inch range expected by 00z Tuesday. Not enough to alleviate the increasingly dry conditions across the area. Temperatures tomorrow will be a bit cooler with the clouds but still 5-7 degrees about normal most area. && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/... As of 250 PM EDT Sunday... A cold front in zonal flow will slowly sink south across the area Monday night, then stall over the Carolinas Tuesday. A wedge of high pressure will follow the front, pushing south along and east of the southern Appalachians. This wedge will remain over the mountains through Wednesday morning and over the foothills and piedmont into Wednesday night. Light to moderate rain is likely along eastern slopes of the North Carolina High County where low level flow will primarily be out of the southeast. The rest of the area will have a more east to northeast flow. This easterly flow is relatively drier and will limit rainfall amounts through the event. For the most part, areas north of the VA/NC border will have mostly cloudy skies and areas of drizzle with a stray afternoon shower. Precipitation falling in the wedge will keep temperatures below normal Tuesday with mainly 60s across the area. Places along the Blue Ridge may have temperatures Tuesday afternoon only warming into the upper 50s to lower 60s. Areas outside of the wedge Wednesday will have temperatures warming into the low to mid 70s, while areas inside stay in the mid to upper 60s. && .LONG TERM /THURSDAY THROUGH SUNDAY/... As of 250 PM EDT Sunday... A warm front will break any remnants of the wedge Wednesday night. This warm front will bring well above normal temperatures to the region Thursday with mid to upper 70s across the mountains and lower to mid 80s east of the Blue Ridge. A cold front will slide across the area Thursday afternoon and evening. This front has the potential to bring strong to severe thunderstorms to the area. Cool high pressure will follow this front for Friday and Saturday. High temperatures later in the week will be close to normal. Models are displaying a closed low over the Midwest next weekend, which could bring strong storms and heavy rain into the region next Sunday and/or Monday. && .AVIATION /01Z MONDAY THROUGH FRIDAY/... As of 727 PM EDT Sunday... VFR conditions to generally prevail through 04z, outside of a rogue MVFR visibility shower/storm at Danville near 00z Monday. Risk of showers generally increases after 04z at BLF and LWB with the approach of a cold front and a general lowering in ceilings toward VFR/MVFR. Though confidence is only medium at best, feel most likely onset time at these western terminals not until 10-12z, a couple hours after that at BCB/ROA/LYH and not until after 17z at DAN. Front slows as it moves across, essentially stalling late in the day on Monday into Monday evening, focusing showers and possible storms across the southern third of the airspace into Monday evening. While that should result in shower chances diminishing except at Danville, lingering VFR/MVFR ceilings likely. Winds southwest 5-9 kts until the cold front`s approach, with winds becoming lighter and variable at times during the mid- morning and into early afternoon. A general wind shift to northwest anticipated behind the front late in the day to speeds 4-6 kts. Extended Aviation Discussion... The front will drift to near the NC/VA border by late Monday and stall. Showers will drift from northwest to southeast through the area during the morning, then redevelop with thunderstorms as well near the front during the afternoon. Surface high pressure will wedge southwest into the area Tue-Wed resulting in a more stable air mass and allowing the front to be pushed a little further south, thus removing the threat for convection during the Tue- Wed period. By Thursday, the front will return north as a warm front as a new front approaches from the northwest once again. Showers and thunderstorms will be on the increase Thu-Fri as this front also drifts into the area and stalls. This front will return to the north as a warm front Saturday as a much stronger weather system moves into the southeast U.S. Between the wedge Tue-Wed and the frontal systems in/near the area through the week, multiple and extended periods of sub-VFR aviation conditions are expected through the week. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...JH/RCS NEAR TERM...AL/JH/PC SHORT TERM...RCS LONG TERM...RCS AVIATION...AL/PC
Area Forecast Discussion
National Weather Service San Angelo TX
624 PM CDT Sun Apr 16 2017 .AVIATION... /00Z TAFS/ Expect mainly VFR conditions this evening, then widespread stratus late tonight and Monday morning, resulting in mainly MVFR ceilings at most of terminals, with IFR at KBBD. Expect mainly VFR conditions to return to West Central Texas Monday afternoon. A few thunderstorms are possible this evening at the KSJT/KSOA terminals and going with VCTS between 02Z-06Z. && .PREV DISCUSSION... /issued 342 PM CDT Sun Apr 16 2017/ SHORT TERM... (Tonight and Monday) A weak upper trough across West Texas has kept the low clouds from clearing with temperatures in the 70s at 2PM. A cold front was straddled across the South Plains this afternoon, and a dryline extended south across Far West Texas. These boundaries should trigger storms across the South Plains and along the dry line later today, resulting in the development of thunderstorms. And some of these storms may move east and southeast into West Central Texas overnight. Water vapor satellite also shows a weak upper low moving into the Big Bend and southwest Texas, triggering thunderstorms around Fort Stockton. This feature could impact the I10 Corridor tonight. It seems the ECMWF and the HRRR have a handle on this pattern. The ECMWF prog`s precipitation across the area tonight. HRRR prog`s a batch of storms across the Big Country and another batch across the southern part of the CWA. With MUCAPE Values in excess of 3000 J/KG, look for a few elevate severe storms possible overnight intensifying and may produce large hail and damaging winds. For these reasons, have gone with 50 Pops across the entire area for tonight. Continued low chance Pops for tomorrow since there could be some residual showers and thunderstorms across the area as the weak upper trough will be exiting to the east by tomorrow evening. LONG TERM... (Monday night through Sunday) Isolated, diurnally driven showers and thunderstorms, may persist into Monday evening. An upper level ridge will then build in, bringing subsident and dry conditions through midweek...despite a warm and moist air mass. The potential for a isolated showers and thunderstorms returns Thursday night and Friday in the Big Country, however, ahead of a progressive upper low as it moves from Central Rocky Mountains southeastward across the Texas Panhandle/Kansas/Oklahoma. The main potential for showers and thunderstorms will be Friday night and early Saturday morning, as strong cold front moves through. Rain chances are in the 20 to 40 percent range. Can not rule out a severe storm, as moisture and instability will remain along and ahead of the cod front. There will be warming trend from the lower and mid 80s Tuesday and upper 80s to near 90 Wednesday and Thursday. Cooler and dry conditions are expected Saturday afternoon into Sunday behind the cold front, with highs 70 to 75 and lows 45 to 50. && .PRELIMINARY POINT TEMPS/POPS... Abilene 62 81 60 84 / 50 40 20 5 San Angelo 62 82 60 85 / 50 30 20 5 Junction 61 80 60 82 / 50 40 20 10 Brownwood 59 80 60 82 / 30 40 20 10 Sweetwater 62 80 60 84 / 40 30 20 5 Ozona 62 80 60 82 / 50 20 20 5 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ 21
Area Forecast Discussion
National Weather Service Great Falls MT
937 PM MDT Sun Apr 16 2017 .UPDATE... Updated forecast has be published. The previous forecast remains on track, with only minor adjustments made to precipitation timing. An early look at the available 00z model guidance indicates that the onset of precipitation across the region maybe some 3 to 6 hours slower than earlier expected. Both the 00z RAP and NAM model guidance now indicates that the main precipitation shield ahead of the approaching upper level disturbance won`t begin to affect the Rocky Mountain Front and adjacent plains across North Central Montana until or shortly after sunrise tomorrow. This precipitation shield will then lift from southwest to northeast across North Central Montana through the rest of the morning hours and into the early afternoon. Then, as the cold (-20C to -24) H500 wave moves overhead during the afternoon hours on Monday, steepening lapse rates will provide the chance for scattered convective showers across most of the region. - Moldan && .AVIATION... Updated 2350Z. VFR conditions will prevail over the region during the overnight hours. Then lowering ceilings with rain/snow developing after 12z Mon from west to east over the region. Snow is possible for lower elevations mainly north of Great Falls. Expect one round of precipitation over the north during the morning, then a second round of precipitation mainly for Central/Southwest MT during the afternoon hours. Mountains will become obscured after 12z Monday...with IFR conditions possible at times in areas of rain/snow during the day on Monday. Brusda && .PREV DISCUSSION... /ISSUED 550 PM MDT Sun Apr 16 2017/ Tonight through Monday...A transient upper level ridge axis drifts east across MT this evening downstream of a fairly compact but vigorous upper level low moving onshore into OR this evening. Dry conditions will prevail through most of tonight with increasing cloud-cover ahead of the Pacific low and east to southeasterly surface winds with high pressure setting off to the east and the low approaching from the west. The surface and upper level low move across ID and western MT Monday morning with an an areas of precipitation lifting NE across much of the forecast area during the Monday morning period. Diffluent flow aloft ahead of the low and an upper level jet nosing north into central MT will favor somewhat better precipitation amounts across NW portions of North central MT where 0.10"-0.20" look to occur. Snow levels look to range from around 3000 feet in Glacier county to 5000 feet in SW MT Monday morning as this precipitation band moves through, meaning most lower elevation sites will see little or no snow accumulation though there is some potential for a mix with wet snow. Cut Bank area could see mostly snow though with temperatures right around freezing and Marias pass could pick up 2 to 3 inches of wet snow Monday morning. Onset of the snow in these areas, however looks be during the daylight period Monday morning and intensity of precip is not anticipated to be heavy so any snow accumulations in these areas will be limited to grassy surfaces with roadways remaining wet. Somewhat drier air moves in from the west Monday afternoon with the trough axis, but cooling aloft will likely lead to some convective shower development, primarily across central and SW MT with a few weak thunderstorms possible over SW MT. Hoenisch Monday night through Tuesday...Shortwave disturbance exits to the east with generally fair weather Monday night. Scattered showers with perhaps a few stray lightning strikes return on Tuesday as another weak shortwave moves through southwest MT, with greatest coverage over central and southwestern MT. Cassell Tuesday Night through Sunday...Medium range models start the period off with only marginal consistency. The overall trend that all models agree on is a progressive pattern aloft with temperatures remaining near seasonal average. Main weather making feature during the earliest portion of the period continues to be an upper level low off the Pacific Northwest coast. This system is expected to eject occasional disturbances into a moist west- southwest flow aloft Tuesday night and Wednesday before it moves inland Wednesday night. Shortwave ridging will build over Montana for mostly dry conditions Wednesday night into Thursday. Beyond this time frame, model solutions diverge significantly but the overall pattern continues to take the upper low southeastward into the Four Corners region on Friday. Weak upper level troughing to the north of the upper low now appears to stall out over western Montana so have backed off a bit on PoPs for Friday and Friday night with this package. Significant model differences continue to prevail through next weekend with the GFS being the driest of the assorted models. For now, I have trended the forecast toward a broadbrushed blend which introduces isolated to scattered showers through the weekend with breezy conditions. mpj && .PRELIMINARY POINT TEMPS/POPS... GTF 35 53 37 61 / 10 70 10 20 CTB 31 47 35 57 / 10 90 10 20 HLN 37 53 37 60 / 30 60 10 30 BZN 36 52 34 58 / 10 50 10 30 WEY 32 42 30 46 / 30 70 30 50 DLN 37 51 35 56 / 30 40 10 30 HVR 31 50 33 63 / 10 80 20 20 LWT 33 56 33 60 / 10 70 10 20 && .TFX WATCHES/WARNINGS/ADVISORIES... None. && $$