Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/21/19

Area Forecast Discussion
National Weather Service La Crosse WI
1048 PM CDT Tue Aug 20 2019 .SHORT TERM...(Tonight into Wednesday) Issued at 215 PM CDT Tue Aug 20 2019 Weak frontal boundary dropping south across the local area this evening. Weak low level moisture transport focuses back into the boundary, while RAP soundings point to some elevated instability. Could be enough forcing to spark isolated showers/storms. Models remain in good agreement with sliding an upper level trough axis southeast across the Upper Mississippi River Valley Wed/Wed night. Meanwhile at the sfc, high pressure builds in from the plains. In addition, little if any saturation for this northern stream wave to tap into. Outside of some clouds, expect minimal impacts from the upper level trough as a result. However, to the southwest, an MCS is expected to kick off across the central plains tonight - taking an eastward track Wed. Expect some waning in areal extent/intensity as it loses the influence of the low level jet, but still follows along the edge of the main bubble of instability. Most models would keep the pcpn just south of the forecast area, although a few suggest it could skirt across northeast IA/southwest WI. Trending the forecast dry for the moment. .LONG TERM...(Thursday through Tuesday) Issued at 215 PM CDT Tue Aug 20 2019 Looking like an extended period of dry, and relatively cool conditions for the rest of the week - or at least through Sat. Upper level shortwave ridge builds into the area Thu, easing east early Sat. The sfc high follows suit, shifting across the eastern great lakes by 12z Sat. Several dry and mostly sunny days should result. Upper level trough then progged to push in from the northern plains late Sat night-Sunday. Southerly fetch picks up ahead of the shortwave, returning warmer-more moist air to feed the system. Expect showers/storms to develop in response to the lift/moisture interaction...with high chances to the north. How far south, mostly along and ahead of an associated sfc front, is in question - and certainly tough to answer this far out. Some hints that an MCS could spark Sun night to the southwest, moving east on Mon. All said, Sun and Mon currently holding a decent shot for rain for the area. && .AVIATION...(For the 06Z TAFS through 06Z Wednesday night) Issued at 1048 PM CDT Tue Aug 20 2019 Brief MVFR conditions are possible tonight in stratocumulus. A cold front and weak disturbance sags southeast across the area bringing a few showers overnight. High pressure builds in on Wednesday providing VFR conditions. Mid to high level clouds will be found at the TAF sites at times from mid Wednesday morning into the afternoon. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. IA...None. && $$ SHORT TERM...Rieck LONG TERM....Rieck AVIATION...Wetenkamp
Area Forecast Discussion
National Weather Service Denver/Boulder CO
923 PM MDT Tue Aug 20 2019 .UPDATE... Issued at 839 PM MDT Tue Aug 20 2019 Minor updates were made to POPs to reflect the current convection. Right now, it appears the majority of the storms will be sub- severe this evening. However, better instability exists over the I-76 corridor northeast of DIA up to the Cheyenne Ridge as the RAP mesoanalysis has over 2000 j/kg of mixed layer CAPE with up to 3000 j/kg near the Nebraska border. This is enough to support the potential for a severe storm or two with large hail the primary threat. The Severe Thunderstorm Watch goes until 11pm for Weld and Morgan Counties which should be sufficient to encompass the threat. Storms may continue into the early morning hours across the far northeast corner. Stratus and fog may develop but there is low confidence on the fog. && .SHORT TERM...(This evening through Wednesday) Issued at 220 PM MDT Tue Aug 20 2019 Fair weather CU over the higher terrain and east-west ridges this afternoon will eventually give way to convection by this late afternoon. By 21z, will expect to see some isolated gusty convection fire off the mountains, foothills and ridges and expect these to migrate off onto the east plains while strengthening into the evening hours as they move into much better moisture. Latest NAM12 run has MLCAPES out on the far northeast plains in the 3000-3800 J/kg range on the southern slope of a theta-e ridge extending from southeast Wyoming eastward into western and southern Nebraska. Rich surface boundary layer moisture of 8-10 g/kg will reside over the far NE plains lending to the potential for strong to severe storms this evening along with the potential for heavy rain and large hail. Storm motion for this evening is on the weak side as 500-300mb layer winds are only in the 15 to 25kt range. A few of the stronger, slower or back-built storms could present some local hydro issues later this evening out along the I-76 corridor mainly northeast of Denver. Behind tonight`s batch of convection will be the passage of much cooler air behind an approaching cold front currently near the Sheridan WY / Black Hills SD vicinity as a decent 1022mb surface high spreads southward across north plains states tonight. Will look for the main wind shift arrival in the 05-07z Wednesday timeframe. This will likely keep a north to northeasterly component to the surface winds overnight and into Wednesday morning along with areas of low clouds towards dawn. For Wednesday, with the initial cool moist, stable air, will look for light easterlies through the morning along with the potential for low clouds and patchy fog over the far eastern plains. Highs along the urban corridor and plains should only reach into the lower to mid 80s. Forecast soundings indicate the profile remaining fairly stable in the lower levels through late afternoon, so with persistent easterlies through the day, the best MLCAPES and boundary layer specific humidities will build up against the Urban Front Range and foothills. Will keep the scattered pops across the area, and at this time will expect the main impact to be heavy rain associated with the storms along with potential local hydro issues. Storm motion from 500-300mb winds aloft is still fairly weak and with surface easterlies and disorganized flow in the low to mid-levels, a few storms may have difficulty exiting locations which may be a problem for flood prone area such as an urban areas and burn scars. With cooler temperatures along with higher daytime dew points and relative humidity, the fire danger should relax for Wednesday. .LONG TERM...(Wednesday night through Tuesday) Issued at 220 PM MDT Tue Aug 20 2019 Scattered thunderstorms will continue into the evening hours along the Front Range and across the northeast plains Wednesday. A few severe storms with large hail will be possible due CAPE climbing to 1500-2500 J/kg and 0-6km Bulk Shear climbing to 30-40 kts. A weak westerly flow aloft will again be over the state Thursday. Surface low pressure over central Colorado and Wyoming will produce southeast winds across eastern Colorado Thursday. This will help keep moisture over the much of the area. Isolated to scattered storms should form over the Front Range and eastern plains Thursday afternoon and evening. Temperatures warm a little over Wednesday`s highs with readings in the mid to upper 80s. On Friday, moisture is starting to get pushed to the east by the westerly flow aloft. May have enough moisture for a few storms. The best chance will be across the eastern plains. With the drying, expect temperatures to warm back around 90 degrees. For the weekend and early next week, the upper level ridge will shift south as westerly flow aloft increase. This will dry out the airmass and warm it up. Dry conditions with highs in the 90s is expected for the weekend. A weak cold front may back into the area Sunday night and early Monday. This will bring cooler air with highs expected to reach the upper 80s for Monday and Tuesday. Could see enough moisture return to the area for storms on Tuesday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 839 PM MDT Tue Aug 20 2019 A thunderstorm or two may briefly pass over the terminals this evening with minor, if any, impacts. Outflow boundaries may continue to develop and push through the terminals tonight shifting winds temporarily. The next concern shifts to the possible development of stratus during the early morning hours. With plenty of low level moisture in place, it is better than a 50 percent chance that stratus develops so I included a from group for it at DEN. There is some uncertainty, though, as most models have downslope winds for much of the night so it is not a sure bet. Strong thunderstorms will be possible Wednesday afternoon with gusty winds and lower ceilings the primary threats. && .BOU WATCHES/WARNINGS/ADVISORIES... None. && $$ UPDATE...Danielson SHORT TERM...Fredin LONG TERM...Meier AVIATION...Danielson
Area Forecast Discussion
National Weather Service Dodge City KS
635 PM CDT Tue Aug 20 2019 ...Updated aviation discussion... .SHORT TERM...(This afternoon through Wednesday night) Issued at 1145 AM CDT Tue Aug 20 2019 Quiet across SW Kansas late this morning, with only some scattered cirrus and mid cloud. With downsloping SW winds increasing through the afternoon, and gusting to near 30 mph, temperatures will soar this afternoon despite local cooling from minimal cloud cover. Increased max temperature grids 1-2 degrees across the board, with many locations reaching 100-103. Also issued a heat advisory across the SE zones 1-7 pm, where lingering humidity will push the heat index over 105 for several hours this afternoon. Convection evolution this afternoon is complex and a bit perplexing. A strong 596 dm upper high is centered just east of Medicine Lodge at midday. Apparently, a weak disturbance is rotating around this anticyclone, northward through the Texas panhandle, that has already initiated weak convection near Amarillo. HRRR and other CAMs, with support from 12z GFS, develop scattered convection across SW KS starting around 3 pm. Increased pops to scattered category for the central/eastern zones after 3 pm. Storms will form in a very hot, well-mixed boundary layer with downburst wind gusts to 60 mph being the primary threat. Midlevel clouds and scattered showers/embedded thunder will persist much of the night, especially N/NE zones, fed by the low level jet. Much more organized MCS with attendant hail/wind threat is expected to remain well to the north of SW KS tonight, focusing on Nebraska. MCS-outflow reinforced cold front is expected to be along the Kansas/Nebraska border at sunrise Wednesday. The front is shown by all models to make steady southward progress through Kansas during the daylight hours Wednesday. 12z NAM/GFS/extended HRRR show excellent agreement showing strong convective initiation along the cold front across SW KS around 3-4 pm. With the added focus of the boundary, CAPE/shear will support strong to marginally severe convection with locally very heavy rain. SPC 5% wind/hail probability for the entire CWA is justified, and increased severe risks may be assigned once the cold front focusing mechanism is nailed down more specifically. The heat will relax Wednesday, but temperatures will still have time to reach the mid to upper 90s ahead of the incoming front across the southern counties. .LONG TERM...(Thursday through Tuesday) Issued at 200 PM CDT Tue Aug 20 2019 Heat relief is expected on Thursday behind the frontal boundary. 12z NAM shows the strongest cooler air wedge coming into SW KS, perhaps enforced by a spurious closed low passing over Kansas aloft. 12z GFS is not far behind, forecasting surface temperatures holding in the 70s most of the day for most zones, with some 80s near the Oklahoma/Colorado borders and even upper 60s NE zones. Model guidance is trending strongly cooler for Thursday, but much of this cooling is a function of holding cloud cover through the daylight hours. If the clouds can hold through 5-6 pm, then the coolest guidance will verify. NBM appeared too warm in the mid to upper 80s, and trimmed substantially, but stayed above the cool guidance. Regardless, Thursday will be the most comfortable day we have seen in some time. Kept modest pops in the grids Thursday and Thursday night as the front meanders and slowly washes out. However, models are trending eastward with the most significant rainfall during this period, focusing in central/eastern Kansas. A warming trend will occur Friday through Sunday. The only disparity in the models is exactly how quickly this will occur. Model consensus and 12z MEX guidance suggests afternoon temperatures will return to near 100 on Sunday. 12z ECMWF supports this thinking, with the highest thickness values on Sunday, enhanced by prefrontal compressional heating ahead of the next cold front scheduled for Monday. Rain chances will also dwindle during the Friday through Sunday time range, with most locations remaining dry. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 635 PM CDT Tue Aug 20 2019 Widely scattered to isolated thunderstorms will continue into the early evening before diminishing due to the loss of daytime heating. The storms will mainly be in the vicinity of Dodge City and Hays. A cold front will move south through western and central Kansas during the day Wednesday. Widely scattered thunderstorms are expected to develop again along the front. VFR to MVFR cigs may develop in the Hays area toward the end of the period. && .PRELIMINARY POINT TEMPS/POPS... DDC 71 96 66 79 / 20 30 60 30 GCK 67 95 64 79 / 30 20 60 30 EHA 68 95 64 89 / 20 20 60 20 LBL 70 97 65 90 / 20 20 60 20 HYS 69 89 65 79 / 30 50 60 40 P28 73 98 69 87 / 10 20 50 30 && .DDC WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 7 PM CDT this evening for KSZ066-081-088>090. && $$ SHORT TERM...Turner LONG TERM...Turner AVIATION...Gerard
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
1154 PM EDT Tue Aug 20 2019 .AVIATION... Mid level clouds in wake of MCV enhanced vorticity max will fade overnight with at least some chance for a period stratus/fog early in the morning given moisture from evening rain and light flow. Any MVFR conditions will lift by mid morning as southwest flow increases in advance of approaching cold front. This front bring a wind shift late in the day and perhaps a period of lower VFR cigs. For DTW...VFR conditions will start the period, but a period of MVFR cigs/vsbys may occur by daybreak given moist low levels and light winds. Otherwise, cigs in/around 5kft will be possible Wednesday before cold fropa by early evening scours lower moisture out to some degree. .DTW THRESHOLD PROBABILITIES... * Moderate confidence in cigs aob 5kft late tonight/Wednesday morning, low late Wednesday. && .PREV DISCUSSION... Issued at 337 PM EDT Tue Aug 20 2019 DISCUSSION... Scattered showers and thunderstorms continue oriented southwest to northeast along an area of subtle isentropic ascent and where greatest moisture transport vectors have set up across the state. A couple of moving pieces to note and watch out for heading into the remainder of the afternoon and evening. To start, SPC RAP guidance and latest hi-res models hold CAPE between 1500 - 2000 J/kg mainly across the Tri-Cities area into the Thumb (tied to increase moisture surge) and a secondary area of higher CAPE up to 2000 J/kg building in across the southern Metro area. Additionally, low-level lapse rates aoa 7C/km in conjunction with supportive TEI profiles and larger dew point depression spread at the surface help support the idea of strong wind gusts to 40 mph, with a possible isolated downburst to 60 mph. Hail cannot be completely ruled out as mid- level lapse rates also hold around 7C/km with effective bulk shear around 25 knots. Second, an MCV complex currently located over southern Lake Huron and northern Indiana has maintained a more east to west propagation, contrary to many CAMS advertising a northwest to southeast propagation. This system is also translating faster to the east relative to the 12Z hi-res output. Given that the MCV complex is moving east into an area of high instability, there is a chance this system will hold together and produce showers and thunderstorms for the southern Metro region centered between 20-04Z. Prior to the potential arrival of the MCV, amplification of a shortwave will allow the nose of higher theta-e to fill in across the Metro area between 20 - 00Z, which will bring the chance to see isolated to scattered showers and thunderstorms. Overall the main message -- Isolated to scattered thunderstorms will remain possible from Flint up to the Tri- Cities and Thumb this afternoon, with isolated to scattered thunderstorm chances expanding across the Metro area during the early evening onwards. Low-level cap in place may help diminish activity vs. the competing instability in place but the approaching MCV will have to continue to be monitored as it travels east towards the cwa. There will be a marginal risk for severe weather for all of SE MI, mainly for wind gust concerns. PV anomaly (tied to the MCV) is projected to move east of the cwa by 06Z Wednesday and will travel into New England by Wednesday afternoon, leaving SE MI under zonal flow in the mid-levels. Subsidence on the back side of the anomaly will allow for clearing of cloud cover overnight, especially for the Tri-Cities and Thumb with more active subsidence in place. Did not include in this forecast package due to uncertainty, but given residual precipitation and moist boundary layer with the subsidence, will need to watch for fog development overnight. Upper-level closed low and developing surface low pressure system will move east across Ontario Wednesday into Thursday and will allow a cold front to pull across SE MI sometime between Wednesday morning - Wednesday afternoon and will bring the chance for showers and thunderstorms. Will carry a chance of precipitation through the passage of the front as atmosphere is relatively dry (1000-500 MB RH aob 50%) and lack of overall synoptic forcing. Warm and humid temperatures will be able to hold on through the afternoon with highs in the 80s, but relief will fill in during the evening and will lead to overnight lows in the 50s to lower 60s and DP dropping into the 50s. Southern periphery of a high pressure system to fill in throughout Thursday which will start an extended period of dry weather with lower humidity and temperatures that are below the seasonal norm with highs in the 70s. Friday will be cloudy and cooler as upper level trough lingers over the region. A cold front dropping through the state in advance of Canadian surface high pressure will keep clouds prevalent with northerly flow but model soundings look very dry minimizing the rain potential. Cool northerly flow continues Saturday into Sunday as the surface high, centered to our north over Ontario, slides east. An amplifying mid level ridge axis will then pass over on Sunday allowing southern return flow back into the state. After a few days where highs only reach in the 70s, temps on Sunday should finally rise back into the low 80s which is normal for late August. Next shot for showers will hold off til around Monday when a strong mid level wave and associate surface low lift through the northern Lakes. Increasing warm air advection ahead of the front will push temperatures into the mid 80s Monday. MARINE... Light southerly winds this evening will give way to northwest winds tomorrow as a cold front drops south through the Central Great Lakes. A push of much cooler air over Lake Huron Wednesday evening will result in winds increasing to 20 to 30 knots, with brief/slightly higher gusts possible over northern Lake Huron. Winds will gradually diminish on Thursday into Friday as high pressure nudges into the region from the northwest. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...NONE. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....DG DISCUSSION...AM/DRK MARINE.......SF You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
335 PM MDT Tue Aug 20 2019 .SYNOPSIS... Shower and thunderstorm activity will be on the upswing this afternoon and through much of the week, with scattered to numerous thunderstorms expected into the early evening hours. Storms will be slow-moving, and will tend to produce highly localized downpours and flooding, while other areas remain dry. Thunderstorm coverage will be around 30 to 50 percent in the lowlands. Temperatures will slowly cool back down into the 90s Wednesday and Thursday. Drier conditions are expected by Sunday, with temperatures warming back up early next week. && .DISCUSSION... RAP analysis has the subtropical ridge centered roughly over New Mexico this afternoon, with light and variable steering flow. Low level moisture did push into the region overnight, but most areas near and west of the Rio Grande have seen dewpoints mix out into the mid-40s. Despite this, PW values remain around 1.25 inches. Dewpoints remain in the 50s over the Tularosa Basin and Hudspeth County. Convection was fairly impressive when it fired up in the higher terrain late this morning, and continues to pulse up now and then, even in parts of the lowlands. NAM/GFS suggest moderate instability axis focused near the Rio Grande, with and 850-700 mb moist axis just west of the Rio Grande, despite surface dewpoints having mixed out into the upper-40s. Overall, the UofAZ WRF (various 12Z and 06Z runs) appear to be doing fairly well with on-going convection, and suggest scattered coverage across most areas east of the Divide through early evening, somewhat favoring areas west of the Rio Grande. Given the higher dewpoints further east, and on-going trends, we will keep scattered coverage in place east of the Rio Grande this evening as well. Heading into tomorrow, the subtropical ridge begins breaking down into two centers, with a weakness over NM where plenty of recycled mid-level moisture will remain trapped. Temperatures aloft will remain more favorable than they have been much of the season (around -6C at 500 mb... whereas we`ve been seeing a lot of -3s and -4s this year), with moderate instability developing in the afternoon. There`s some hint of a weak surface trough in the vicinity of the Rio Grande as well, and with dewpoints remaining in the lower-50s, expect scattered coverage of thunderstorms again tomorrow, and a relatively active day. Weak steering flow will continue, resulting in localized heavy rainfall and highly localized flooding. For Thursday, a shortwave trough over the Central Rockies will skirt northern New Mexico, while down south we`ll remain in the weakness between the subtropical ridge centers with trapped/recycled upper level moisture remaining in place. Areas east of the Rio Grande may be favored for thunderstorm coverage Thursday afternoon/evening, as slightly drier air aloft looks to push into the NW portion of the area. Thunderstorm activity will slowly diminish Friday and Saturday, with mostly dry conditions expected by Sunday and Monday as the upper ridge redevelops to our west, and drier air aloft moves in from the north. The ridge looks to slowly shift eastwards Monday into Tuesday, suggesting continued drier conditions and temperatures warming back up again. && .AVIATION...Valid 21/00Z-22/00Z... P6SM FEW-SCT080-100 SCT-BKN150-200 through much of the period. Isolated to scattered VRB25G40KT 1-3SM TSRA BKN030-040 possible through 06Z, mainly mountains and lowlands between Continental Divide and Rio Grande. Thunderstorm coverage increases to isolated/scattered lowlands and numerous mountains after 18Z. Winds mainly east to southeast AOB 12KTS except near thunderstorms. && .FIRE WEATHER... Low level moisture has returned to the region with showers and thunderstorms over area mountains this afternoon with some isolated to scattered coverage over the lowlands into the evening. Moisture will become a little deeper Wednesday with increasing storm coverage, especially over the mountains. The main threat with these storms the next couple days will be locally heavy rain as storm motion will be very slow. Temperatures will fall to near normal and relative humidities rising above 20 percent. An upper high will start to build back over the area starting Friday and really gets established for the weekend into early next week. This will bring a return to very hot and dry conditions with highs over the lowlands likely back near or above 100 degrees with minimum humidities back into the teens. && .PRELIMINARY POINT TEMPS/POPS... El Paso 75 97 72 95 / 20 10 30 20 Sierra Blanca 69 93 68 92 / 10 0 20 30 Las Cruces 71 95 66 94 / 40 20 50 10 Alamogordo 70 96 67 95 / 20 30 40 30 Cloudcroft 56 73 53 73 / 30 70 50 50 Truth or Consequences 70 94 67 95 / 40 40 40 20 Silver City 66 88 61 89 / 30 60 40 20 Deming 71 96 66 95 / 50 20 50 10 Lordsburg 72 97 67 95 / 10 30 40 10 West El Paso Metro 76 97 72 96 / 20 10 40 20 Dell City 71 98 71 98 / 0 0 20 30 Fort Hancock 75 100 73 99 / 0 0 20 30 Loma Linda 71 92 69 90 / 30 10 30 30 Fabens 75 97 72 95 / 10 0 30 20 Santa Teresa 73 96 69 95 / 30 10 40 10 White Sands HQ 74 96 71 95 / 40 30 40 20 Jornada Range 69 95 66 94 / 40 40 50 10 Hatch 70 96 66 96 / 40 40 50 20 Columbus 73 96 69 95 / 40 10 50 10 Orogrande 71 96 68 95 / 20 10 40 20 Mayhill 59 82 57 82 / 30 60 40 50 Mescalero 58 82 56 82 / 30 60 50 50 Timberon 58 81 57 80 / 20 50 40 50 Winston 60 85 56 87 / 30 70 40 30 Hillsboro 67 93 63 93 / 40 50 40 30 Spaceport 68 94 64 94 / 40 40 50 20 Lake Roberts 60 88 55 89 / 20 70 30 20 Hurley 65 90 61 91 / 30 50 40 20 Cliff 65 97 60 98 / 10 50 30 20 Mule Creek 67 92 63 92 / 10 50 30 10 Faywood 68 90 63 91 / 40 50 40 20 Animas 69 98 66 96 / 20 30 40 30 Hachita 70 97 65 94 / 30 20 50 10 Antelope Wells 70 95 66 93 / 30 30 50 30 Cloverdale 68 91 64 88 / 30 40 40 40 && .EPZ WATCHES/WARNINGS/ADVISORIES... NM...None. TX...None. && $$ 25-Hardiman / 26-Grzywacz
Area Forecast Discussion
National Weather Service Goodland KS
702 PM MDT Tue Aug 20 2019 .UPDATE... Issued at 655 PM MDT Tue Aug 20 2019 Just completed an update. Coverage of storms has increased along and south of Interstate 70 in northwest Kansas in response to a couple of prefrontal troughs. Mesoscale interaction of storms have also helped to move storms along. This coverage is a little more plus further west than what was in the forecast. So have raised pops in this area. Also surface boundaries have sagged further south over the northern half of the area than what was called for. This plus thunderstorms will make for gusty and erratic winds this evening. Because of all this further updates through the rest of the night will be possible. && .SHORT TERM...(This evening through Wednesday) Issued at 226 PM MDT Tue Aug 20 2019 Upper ridge will be centered over the southern plains with a weak shortwave trough currently emerging out of Wyoming and topping the ridge axis. At the surface, radar shows a surface cold front evident on radar has settled near the Kansas-Nebraska border region with a wind shift to the east behind it. For the rest of this afternoon and tonight, two areas of concern for convection. The first is over the south central to south eastern areas, where latest HRRR continues to show a cluster developing and moving eastward through this evening. These storms will be south of the front in a low shear/moderate instability environment, with the main hazards gusty winds and perhaps marginally severe hail. Later tonight, another thunderstorm complex will move out of northeast Colorado into western Nebraska. These will be north of the front in a high shear/very unstable environment. Expecting a MCS to move across western/central Nebraska through the night, mainly impacting areas to the north, but cannot discount development southward along mesoscale/outflow boundaries through the night. The main hazard with these storms will be strong/damaging winds. Low temperatures will be near normal, mainly in the 60s. Some storms may linger into Wednesday morning as outflow associated with the MCS moving through eastern Nebraska may continue to have mesoscale influences. Areas of fog may also develop in the post frontal upslope flow in the morning. Expecting a lull in activity around midday then new development in the afternoon, mainly in southeastern areas. In fact, HREF members suggest little convection through Wednesday afternoon, holding off until the next weak shortwave comes out of Colorado Wednesday night. Best chances will be in southern/central part of the area south of Interstate 70. Primary hazard will be wind, with only a marginal risk for hail due to nocturnal timing. Heavy rain threat may stay south, but do see some HREF members hitting parts of Cheyenne County, Colorado, during the evening with heavy rain, so cannot totally discount it there. High temperatures on Wednesday will be cooler behind the front and with the morning clouds/fog, ranging from upper 70s/lower 80s in southwest Nebraska to the lower 90s in west central Kansas. .LONG TERM...(Thursday through Tuesday) Issued at 224 PM MDT Tue Aug 20 2019 The extended forecast is a bit messy with daily chances for showers and thunderstorms. Thursday morning, lingering showers will be possible in the western part of the forecast area, mainly along and west of the Kansas-Colorado border. A weak upper level ridge will be in place over the western part of the Dakotas. On the underside of the ridge, an upper level shortwave trough will move through the Tri-State area during the day. Showers and thunderstorms will be possible Thursday afternoon and evening. Storms will fire off along a frontal boundary in northeastern Colorado, moving west into the Tri-State area. Friday into the weekend, a series of upper level shortwave troughs will move through the Central Plains. Showers and thunderstorms, while not widespread in coverage in the forecast area, will be possible through Saturday. Monday, a broadening upper level trough will extend from British Columbia, Canada to Minnesota and south into the Dakotas. The Tri- State area will be under northwest flow aloft as a shortwave trough moves through the larger scale upper trough. Meanwhile, a lee cyclone will develop Sunday night and progress eastward on Monday. Cannot entirely rule out a chance of precipitation early Monday morning, but am thinking we will remain dry through much of the day. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 536 PM MDT Tue Aug 20 2019 For Kgld, at this time vfr conditions are expected through the period. East winds near 14 knots will shift to the southeast at 19 knots with gusts to around 27 knots. From 06z to 11z, southeast winds near 8 knots are expected with 6SM BR expected to develop around 09z. From 11z to 15z east winds near 8 knots and the light fog are expected. This is the time period where possible sub vfr conditions due to ceilings. At 15z east northeast winds near 15 knots will continue until 22z. At that time the winds will become northeast near 15 knots with gusts to around 22 knots. For Kmck, vfr conditions are expected through the first half of the period. Otherwise, east winds near 15 knots with gusts near 23 knots are expected until 04z. From 04z to 07z the winds will be southeast at 6 knots. From 07z to 15z east to northeast winds of 6 to 12 knots are expected as thunderstorms will be near the site along with fog of 6SM BR. From 09z to 12z, vfr conditions will change mvfr and continue until 15z. Ifr conditions are expected from 15z to 18z with northeast winds of 15 knots with gusts to 23 knots. From 18z to the end of the period east northeast winds near 10 knots are expected as mvfr conditions will become vfr around 22z. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...BULLER SHORT TERM...024 LONG TERM...AW AVIATION...BULLER
National Weather Service Wilmington OH
1000 PM EDT Tue Aug 20 2019 .SYNOPSIS... Several mid/upper level disturbances will move east through the region through Thursday, with a slow-moving surface frontal boundary drifting south during this time period. With seasonably warm and humid conditions persisting through Thursday night, periods of scattered showers and storms will be possible before drier conditions filter in area-wide for the upcoming weekend. Slightly below normal temperatures are expected for this weekend with generally drier and sunnier conditions. A few isolated storms may be possible by late Sunday afternoon. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... Subsidence has taken hold of the ILN CWA behind the widespread convective activity this afternoon, with the entire forecast area currently clear of any precipitation. In fact, much of the CWA is clear of any low clouds. Attention overnight will turn to a shortwave currently moving eastward along the IN/MI border, which at the very least appears likely to produce an increase in clouds, as satellite imagery currently supports. Earlier NAM/GFS projections of more widespread precipitation overnight appear unlikely to occur, but even recent HRRR runs do suggest some scattered showers in the northern half of the forecast area, so some PoPs will be kept in overnight. Current conditions and recent RAP/HRRR runs also support lower temperatures this evening, especially with the clearing that should be observed for the first segment of the overnight period. Min temps were lowered by a couple degrees, with values now expected to reach the middle to upper 60s. This is still fairly warm, and the surface Tds in the upper 60s to around 70 would suggest that temperatures will not be able to fall too much further than that. The possibility of fog is also worth mentioning, but for now it appears that in a general sense, this should be limited to MVFR-type visibilities. Previous discussion > A corridor of isolated to scattered thunderstorms have developed in a moderately to highly unstable environment entrenched across the heart of the ILN FA. This activity continues to blossom out ahead of a slowly-decaying MCS with attendant MCV noted on mosaic radar further to the north/west in north-central IL. For the rest of the afternoon, the corridor of scattered storms currently approximately coincident with the I-75 corridor will continue to drift east-northeast as additional isolated to scattered activity develops ahead of the decaying complex tracking south-southeast through central/southern Indiana. While the MCS-generated convection is generally moving into a favorably unstable environment characterized by MLCAPE in excess of 2500j/kg and DCAPE of 1000-1200j/kg, the leading edge continues to push further away from the MCV itself -- essentially outrunning the source that has kept it going for this long. Nevertheless, this activity is likely to trend a bit further south of southeast through mid/late afternoon -- likely grazing and impacting only the Tri-State area and points south/west of this particular area. Elsewhere, any isolated to scattered activity will be more pulsy/airmass-driven opposed to along the leading edge of a cohesive line/MCS. It is the pulsy type activity that will likely pose the greatest strong/damaging wind risk through early evening -- especially coincident with an environment that will support downward acceleration of healthier cores. Even with this said -- the highly unstable environment, with good instability aloft, will also support instances of large hail with the better/stronger cores. The best coverage of storms will gradually shift from western OH/eastern IN/northern KY from mid-afternoon through central OH and northeast KY by early this evening. There seems to be fairly good agreement in the short-term hi-res CAMs showing a downtick in convection near/past sunset as the environment becomes worked over and subsidence behind the main MCS overspreads the ILN FA. Feel pretty confident in a trend toward drier conditions by/past sunset this evening, with just a few isolated showers possible past this time period as some midlevel energy continues to propagate through the mean northwest flow in the area. However, as previously mentioned, subsidence behind the main MCS structure diving south-southwest through central KY could be enough to stifle additional isolated shower activity further north in an environment that will be fairly used up by late evening into the overnight. Highs for today have reached into the lower 90s but have likely already plateaued due to the overspreading of clouds/precipitation through the remainder of the local area over the next several hours. Some light fog will be possible late overnight with the nearly saturated low level environment. However, the pressure gradient will not completely relax -- lending itself to some uncertainty in exactly where and how widespread any fog development will be. Therefore, have not included in the official fcst although certainly observational trends will be monitored closely to see if this may eventually be warranted. Lows tonight will bottom out in the upper 60s and lower 70s area-wide. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... After any fog/stratus lifts/dissipates by late morning on Wednesday, anticipate some diurnally-enhanced Cu to develop in the region. Although the frontal boundary will still be stretched in an E-W fashion across the northern Ohio Valley on Wednesday, the absence of any focused mid/upper level disturbance and/or source for forcing is likely to keep an diurnally-driven activity to mainly isolated in nature. The approach of a disturbance by late evening may help spread some higher chance PoPs into the far western ILN FA by late evening into the overnight hours -- especially as we near the end of the short term period by Thursday morning. However, with a relatively strong cap in place, anticipate that coverage will be far less than is the case today. Scattered showers and isolated thunderstorms will be on the increase from the west towards sunrise Thursday as more S/W energy ejects east through west-central and central Ohio Valley. Highs on Wednesday will again top out around 90 degrees near the Ohio River and mainly mid to upper 80s near/north of the I-70 corridor. Heat indices south of the I-70 corridor will again be in the mid/upper 90s. Lows Wednesday night will fall into the mid/upper 60s in the north to lower 70s south of the Ohio River. && .LONG TERM /THURSDAY THROUGH TUESDAY/... Period begins with a cold front around the Ohio River. The front will provide convergence and lift in the southern part of the fa, giving the best PoPs around and south of the Ohio River. Went will likely PoPs in the far south. The front will continue to sag south Thursday night into Friday. This will keep chance PoPs in the region for Friday. By Saturday, high pressure will be settling in across the Great Lakes. This will bring cooler and drier conditions. On Sunday, an inverted trof will bring increasing humidity back into the region along with a chance of thunderstorms to northern Kentucky and the Scioto Valley. Thunderstorm chances will increase Monday and Tuesday as heat and instability increases. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Chances for thunderstorms this evening have diminished, leaving just a few showers left in the area. The main concern overnight will be the development of MVFR visibilities and MVFR/IFR ceilings. The lowered ceilings appear most likely to develop at KDAY (where IFR is quite possible) and KILN/KCMH/KLCK (where MVFR is most likely). Some visibility restrictions are possible at all TAF sites, though IFR visibilities appear generally unlikely as of now. Any visibility or ceiling restrictions should improve by 15Z, with quiet conditions expected heading into the afternoon, and WSW winds generally at or below 10 knots. A chance of pop-up showers and storms is in the forecast for late afternoon, but this will be handled with a VCSH for now, as storm coverage should be fairly light. OUTLOOK...Thunderstorms will remain possible at times through Friday afternoon. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...KC NEAR TERM...KC/Hatzos SHORT TERM...KC LONG TERM...Sites AVIATION...Hatzos
National Weather Service Jackson KY
954 PM EDT Tue Aug 20 2019 .UPDATE... Issued at 954 PM EDT TUE AUG 20 2019 Outflow boundary has shifted into southeast Kentucky with some ongoing showers continuing ahead of this boundary. Activity is starting to fade with the loss of daytime instability, but a few showers will continue over the next hour or so before this activity shifts southeast and weakens further. This will provide a fairly quiet overnight period. However, CAMS continue to support some redevelopment across a portion of east Kentucky towards 08z or 09z. Given some MUCAPE holding its ground in southeast Kentucky, cannot rule out some redevelopment late tonight, and thus, will bring some low end pops back into the forecast at this time. Most areas will stay dry through the night. Rain chances on Wednesday look to remain fairly sparse as well based on the latest model guidance suggesting a quieter day may be seen across the area. UPDATE Issued at 745 PM EDT TUE AUG 20 2019 Several boundaries continue to be the focus for showers and storms. The first one is from Lawrence county southeast to Bell and Knox county. Outflow from more organized earlier day convection is spread into our western counties, but this outflow is running into an area already worked over from earlier convection. Thus, convection associated with this boundary has shifted more southward and that trend will continue over the next few hours with rain chances gradually ending from northwest to southeast as this outflow continues to push southeast. The outflow could stall somewhere in southeast Kentucky and could led to redevelopment later tonight or tomorrow, but will focus more on that later, keeping some rain chances in late tonight and tomorrow to account for that potential. Otherwise, looks like a period of drier weather will be seen overnight. && .SHORT TERM...(This evening through Wednesday night) Issued at 431 PM EDT TUE AUG 20 2019 A closed low to our SE and incoming shortwave are both impacting the CWA today. Once our CAP was reached, showers and thunderstorms starting quickly popping up across the CWA early this afternoon. However, with very little wind aloft, there is no steering flow and storms are not moving very quickly...rather pulsing up, becoming strong, and then collapsing near their origin. On the converse, a strong MCS is diving SE from Illinois this afternoon, but models continue to show a diminishing trend as the system reaches Kentucky. The latest CAMS show the line reaching the western CWA between 23 and 0Z, and falling apart around the same time, with only isolated to scattered showers and thunderstorms expected across the CWA through 3Z. Since there has been good agreement between the CAMs throughout much of the day concerning the diminishing of this line and mostly dry conditions thereafter through 6Z, did not include much in the way of pops during this time period. However, after 6Z, the HRRR and NAM12 both point at another round of showers and thunderstorms developing across the CWA heading into the early morning hours as the above-mentioned shortwave moves across the CWA. Coverage will increase to scattered across the CWA throughout the day as we increase our instability with daytime heating. Still expecting hot temperatures, with heat indexes near 100 degrees, perhaps only a few degrees cooler than today. Wednesday night, heights will begin to lower across the state as a closed upper level low moves SE across eastern Ontario and western Quebec. A cold front is also forecast to shift southward towards the state, with scattered showers and thunderstorms expected to continue throughout this overnight as a result. A more focused east to west oriented band may develop across the central portion of the CWA according to the latest CAMs. Given the cloud cover both tonight and tomorrow night, temperatures will remain quite mild. Lows will be around 70 each night, perhaps a 2 to 3 degrees cooler in the deepest valleys. .LONG TERM...(Thursday through Tuesday) Issued at 420 PM EDT TUE AUG 20 2019 The models are in fair agreement with the upper level pattern through much of the extended. A deep northern stream trough will progress over the northeastern CONUS, with zonal flow over Kentucky. Ridging will then take hold over the northeastern portion of the country, as well as a trough over the north-central CONUS, for late weekend into early next week. At the surface, a cold front will approach the Commonwealth early Thursday. By the afternoon, the front will slow and eventually stall over the state. This front will linger through Friday before moving off to the south for the start of the weekend. MUCAPE values from GFS model soundings average about 2500 J/kg Thursday and Friday afternoons. Therefore, the better chance for showers and storms is expected from Thursday through Friday. High pressure will then build over the northern portion of the Great Lakes and northeastern CONUS through Monday. By Tuesday, another system over the Plains will progress eastward, with a warm front slated to move over western Kentucky early Tuesday. This pattern will keep daily chances of showers and afternoon/evening storms for eastern Kentucky through the end of the forecast period. High temperatures will be in the mid 80s Thursday, but FROPA will cause highs to only be in the low 80s through Saturday. Highs will then gradually increase to be in the mid 80s by Tuesday. Lows will generally follow a similar pattern, beginning in the upper 60s Friday morning. Lows will then drop to be in the mid 60s through Sunday before returning to the upper 60s Tuesday morning. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 745 PM EDT TUE AUG 20 2019 While the majority of the period will feature VFR conditions, there is some small potential for a few showers or storms late tonight or tomorrow, but confidence is low on coverage and location to include anything in the TAFs at this time. Thus, will run with VFR TAFs for now. Light winds will be seen through the period. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KAS SHORT TERM...JMW LONG TERM...CGAL AVIATION...KAS
Area Forecast Discussion
National Weather Service Mobile AL
848 PM CDT Tue Aug 20 2019 .DISCUSSION...See updated information for land areas below. && .UPDATE...Overall the afternoon forecast package remains on track. Just included some patchy fog development tonight to the current forecast. /08 && .PREV DISCUSSION... /issued 701 PM CDT Tue Aug 20 2019/ DISCUSSION...Updated for latest aviation discussion below. AVIATION... 00Z issuance...Widely scattered showers and storms linger through early evening before slowly dissipating. Winds become light and variable overnight. Patchy light fog is possible by 06Z across areas that received rain today with visibility dropping to IFR or LIFR for a short period at the TAF sites near sunrise. Showers and storms redevelop by late morning. 07/MB PREV DISCUSSION... /issued 337 PM CDT Tue Aug 20 2019/ NEAR TERM /Now Through Wednesday/...20.12Z upper air analysis shows a trof axis at multiple levels from the Appalachians stretching southwest over the central Gulf coast. At the surface, a weakly defined pressure trof has migrated slowly northward over the I-65 corridor today where visible satellite imagery animations and radar loops continue to show a cyclonic motion to cloud/precipitation elements around the trof axis. Meso-analysis shows deepest Gulf moisture (PWATs 1.9 to 2.2 inches) along and southeast of I-65. Scattered to numerous showers and storms have used up instability with mixed layer CAPE values in areas where it hasn`t rained ranging 1000-1500 J/KG over the land zones. Storm cores have had a hard time maturing this afternoon, with over-all core heights staying below -20C height at ~ 26.2 KFT per RAP BUFR soundings. Although storm growth has been lacking, deep layer shear being non-existent and mid level lapse rates ~ 5.5C/KM, forecasters still cannot rule out a few afternoon perhaps early evening storms becoming briefly strong. Deep layer environmental moisture supports some storms being efficient heavy rain producers. Going into the evening, ensembles of the high resolution models show a rapid decrease in coverage. Some patchy fog possible late in the night in those areas that received heavier rains today. Overnight lows mostly in the lower to mid 70s. A weak shear axis aloft remains positioned over the southeast US and central Gulf coast on Wednesday. With deep layer moisture holding and with onset of daytime instability, scattered to perhaps numerous showers and storms are expected. Daytime highs range from 88 to 93. /10 SHORT TERM /Wednesday night Through Friday night/...An unsettled weather pattern will remain in place through the short term. A very moist airmass with precipitable water values around 2 inches combined with an upper level weakness will continue to generate scattered to locally numerous showers and thunderstorms each day. Showers and thunderstorms will start near the coast in the morning and spread inland through the late morning. Convective coverage will be most numerous over the land areas during peak daytime heating. The upside to the additional rain and associated clouds will be temps that will be at or slightly below normal. /13 LONG TERM /Saturday Through Tuesday/...Very little change in the pattern through the extended range as plenty of deep layer moisture will continue across the Gulf coast with precipitable water values over 2 inches. This will continue the pattern of diurnally driven scattered to locally numerous showers and thunderstorms each day. /13 MARINE...A light mostly onshore flow continues over the marine area as a ridge of surface high pressure continues to stretch from the western Atlantic to the north central Gulf. Winds, waves, and seas will be locally higher near thunderstorms through the forecast period. Conditions will also remain favorable for isolated waterspouts, especially during the morning and early afternoon hours. /10 && .MOB WATCHES/WARNINGS/ADVISORIES... AL...None. FL...None. MS...None. GM...None. && $$ This product is also available on the web at:
Area Forecast Discussion...UPDATED
National Weather Service Twin Cities/Chanhassen MN
946 PM CDT Tue Aug 20 2019 .UPDATE... Issued at 946 PM CDT Tue Aug 20 2019 Updated grids to warm overnight temps several degrees. Drier air has been slow to advect in due to the light winds. Dew points have fallen into the 50s from the Brainerd Lakes region and north, but remain in the mid to upper 60s, and even some low 70s, across central and southern MN into WI. The forecast now calls for mid 50s to lower 60s, warmest in the metro and southeast where the drier air will be slowest to arrive. && .SHORT TERM...(This evening through Wednesday night) Issued at 323 PM CDT Tue Aug 20 2019 No significant redevelopment of thunderstorms is expected ahead of the cold front through this evening, thanks in large part to storms that tracked across the area this morning. Although SPC meso analysis shows mlCAPE values have built back up to the 1500-3500 j/kg range ahead of the cold front. Forecast soundings from the RAP and NAM show a strong subsidence inversion in place at h8. Convergence along the front is weak and there`s no discernible upper wave, so this lack of forcing will allow this cap to hold. You can`t completely rule out a stray shower developing along the front north of I-94 from central MN into western WI, but it looks unlikely given the lack of forcing. Already this afternoon on radar on satellite, we`ve seen a few attempts at initiating convection along the front from central MN into the Arrowhead, but nothing has ever been able to sustain itself and expect this trend to continue. For tonight through Wednesday night, high pressure centered to the west of Hudson Bay will be nosing into the upper MS Valley. This will result in some of the best weather you can cook up in MN during the summer. The one thing to watch both Wednesday and Thursday is we will see very deep mixing and will be tapping into a very dry airmass as we mix deeper. So afternoon dewpoints and humidities will likely be lower than what we currently have. During the overnights, the airmass will be too dry to support any widespread fog. Winds will help make sure we don`t see fog tonight, but Wednesday night, we`ll have light/calm winds, so some valley fog will be possible in the the valleys along the MS south of the St. Croix and up the Chippewa Valley into WI, other than that, it`s windows open weather for the next couple of days. .LONG TERM...(Thursday through Tuesday) Issued at 323 PM CDT Tue Aug 20 2019 Pleasant, early fall-like, weather continues into Friday as troughing extending south from eastern Canada keeps cool temperatures aloft over the Upper Midwest, and high pressure over Ontario keeps any systems away from the region. Highs are only expected to reach into the low to mid 70s Thursday afternoon and cool, dry NE winds off of lake Superior will keep dewpoints in the 40s and low 50s. Southeasterly flow picks up on Friday as the high slides off to the east, with temperatures warming a few degrees and more humid air working into the area. Precipitation still looks likely this weekend, but trough and surface front driving the chance for showers and thunderstorms has slowed by a day or so as the ridge over eastern North America slows its progress. Friday evening now looks dry across the area and precipitation may even hold off through most of Saturday across eastern Minnesota/western Wisconsin as the front slowly approaches from the Dakotas. Best chance for precipitation now looks like it will occur from overnight Saturday into Monday, although timing differences still exist among the models during this timeframe. Models have trended stronger with the trough and linger it longer over the region, as the eastern ridge continues to stall its progress. Models show some pretty heavy QPF amounts Sunday into Monday as showers and thunderstorms linger over the area and show PW values approaching 2 inches. Will have to monitor the heavy rain/flooding potential over the second half of the weekend. Drier weather looks possible Tuesday after the front passes, as high pressure briefly moves into the region. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 629 PM CDT Tue Aug 20 2019 VFR conditions and northwest winds 5-10 kts expected through the period. Clouds will dissipate this evening, with high clouds returning to southern MN Wednesday. KMSP...No concerns. /OUTLOOK FOR KMSP/ Thu...VFR. Wind NE 5 kts. Fri...VFR. Wind SE 5-10 kts. Sat...VFR. Chc -TSRA/MVFR. Wind SE 10G20 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ UPDATE...BORGHOFF SHORT TERM...MPG LONG TERM...ETA AVIATION...BORGHOFF
Area Forecast Discussion
National Weather Service Mount Holly NJ
908 PM EDT Tue Aug 20 2019 .SYNOPSIS... A nearby front will lift slowly northward into New York and New England tonight and on Wednesday. A slow moving cold front is forecast to approach from the northwest on Wednesday night and Thursday. The boundary is expected to pass through our region on Thursday night. High pressure is anticipated to follow for the coming weekend and for the early part of next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... The earlier convection across the lower Susqu Valley has diminished for the most part with one or two surviving cells escaping into the southern Poconos attm. Other dying tstms across Delmarva has morphed into a large area of showers across srn DE/NE MD. Going forward, the models are all over the place with the HRRR showing a dry night and the 18Z NAM showing more tstms developing after 6Z. The the nearby front, it seems that some activity should be expected, so I have just refined the Pops a bit mostly N/W and adjusted for present conditions. Patchy fog will probably develop, but with the drier air today, likely not that widespread. With decent cloud cover overnight, temperatures will remain warm and in the 70s through much of the region, with some mid to upper 60s across the southern Poconos and northwestern New Jersey. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... Heat Advisory remains in effect through Wednesday. Another active day is in store for Wednesday as the aforementioned frontal boundary pushes north of the region, placing us firmly in the warm sector. Winds that have been more southeasterly through today will turn more to the southwest and we will see moisture increase across the region once again with dew points rising into the low to mid 70s. Hot and humid conditions will prevail with little relief expected until showers and thunderstorms start to develop and move through the forecast area. A pre-frontal trough will develop ahead of the main front (which arrives Thursday) and will be a focus for thunderstorm development across the region. The main concern will be the potential for severe weather. The SPC has placed portions of our area in the slight risk category, with damaging winds being the main threat. Shear is modest (only around 20- 30 kts) but with CAPE increasing through the day to around 1000-2000 J/KG and plenty of moisture and lift available, we could see some strong to severe storms develop, mainly during the afternoon and evening and primarily to the north and west of the I-95 corridor. Once again, PWATs are running high (up to 2.00") so heavy rainfall will be likely and may result in some flooding concerns. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... We should be solidly in the warm and humid air on Wednesday evening, with ongoing showers and thunderstorms. The warm front is expected to be well up into New England at that time with an approaching cold front extending across the eastern Great Lakes and the lower Ohio River Valley. The showers and thunderstorms are expected to weaken gradually on Wednesday evening with the loss of daytime heating. Partly cloudy and muggy conditions are anticipated for late Wednesday night. The cold front is forecast to extend from northern New England to the Ohio River Valley on Thursday morning. The boundary will likely sink slowly to the south, passing through our region from late Thursday into Thursday night. We are expecting another hot humid day. Heat index values may again approach 100 from the Philadelphia metropolitan area southward. However, conditions seem borderline and we will not extend the Heat Advisory at this point although it may need to be done as we get closer in time. Another round of showers and thunderstorms is forecast ahead of and with the cold front from Thursday afternoon into Thursday evening. Some improvement is expected on Friday as high pressure begins to build down into our region from Ontario. There is a chance of showers and thunderstorms from northeastern Maryland and Delaware into southern New Jersey as the departing front remains nearby to our south. The center of the high is anticipated to shift from Ontario to Canada`s Maritime Provinces over the weekend. This pattern will keep our region in dry conditions with a developing northeast to east flow. Temperatures will be cooler than what we are currently experiencing and humidity levels will be noticeably lower. The onshore flow may bring a return of some moisture early in the new week. We have included a slight chance of showers and thunderstorms at that time. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/... The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY and surrounding areas. Tonight...Isolated showers and thunderstorms this evening. Then more activity N/W after midnight psbl. Otherwise, expect mostly VFR conditions across the region. Some patchy fog psbl and some low clouds S/E. Light and variable winds overnight. Wednesday...Lingering MVFR/IFR conditions (mainly at KACY/KMIV) in the morning should clear by 15Z and then VFR is expected through much of the day. Showers and thunderstorms will again develop across the region and there will be the potential for MVFR or lower conditions to occur during the afternoon and evening, especially from KPHL and northward. South to southwest winds around 5 to 10 knots early will strengthen into the afternoon, with some gusts around 15 to 20 knots possible. OUTLOOK... Wednesday night...MVFR and IFR conditions with a chance of showers and thunderstorms. Southwest wind 5 to 10 knots. Thursday...Conditions improving to VFR. However, there will continue to be a chance of showers and thunderstorms with locally MVFR and IFR conditions. West wind 5 to 10 knots. Thursday night...Mainly VFR. A chance of showers and thunderstorms with locally MVFR and IFR conditions. Northwest wind 5 to 10 knots. Friday...Mainly VFR. A chance of showers. Northwest wind 5 to 10 knots. Friday night...Mainly VFR. Variable wind 6 knots or less. Saturday...Mainly VFR. North to northeast wind 5 to 10 knots. Saturday night...Mainly VFR. Variable wind 6 knots or less. Sunday...Mainly VFR. Northeast to east wind around 10 knots. && .MARINE... Sub-advisory conditions are expected to continue through Wednesday. Seas will generally be around 2 to 4 feet. Winds are expected to pick up from the southwest Wednesday afternoon and gusts may approach 25 knots, especially later in the day. For now, keep winds just below SCA criteria but cannot rule out a few gusts around 25 knots. Isolated showers and thunderstorms may lead to locally higher winds and waves. OUTLOOK... Wednesday night through Sunday...No marine headlines are anticipated. RIP CURRENTS... With waves forecast at 2-3 foot and a 6-7 second period, along with southerly winds 5-10 knots, the risk for dangerous rip currents is low into tonight. Waves in the surf zone will likely remain around 2-3 feet. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...Heat Advisory until 8 PM EDT Wednesday for PAZ070-071-102-104- 106. NJ...Heat Advisory until 8 PM EDT Wednesday for NJZ015-017>019. DE...Heat Advisory until 8 PM EDT Wednesday for DEZ001. MD...None. MARINE...None. && $$ Synopsis...Iovino Near Term...Meola/PO Short Term...Meola Long Term...Iovino Aviation...Iovino/Meola/PO Marine...Iovino/Meola