Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/19/22

Area Forecast Discussion
National Weather Service State College PA
1128 PM EDT Thu Aug 18 2022 .SYNOPSIS... After a foggy start Friday morning, central PA will enjoy a sunny afternoon with lower humidity. Humidity will begin to increase this weekend, with scattered showers possible over the western half of the area by late Saturday, and more numerous showers and storms expected Sun-Tue. Temperatures will trend warmer Fri-Sat before cooling down a bit for Sun into early next week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Earlier thundershowers have come to an end across the area. Clearing skies and calm wind tonight should favor patchy fog formation into early Friday morning. Valley fog has already developed in places where it rained today. Low temperatures in the low 50s to low 60s will be near climo, but a few to several degrees warmer than last night. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Fog fades early Friday morning, giving way to plenty of sunshine to end the week. MaxT trends +5F warmer day/day with above average highs in the 80-90F range. Despite a few hundred J/kg CAPE, dry air aloft should prevent anything but a stray shower from developing during peak heating. An upper level jet streak should bring at least some high clouds to the southeastern potion of our CWA Fri evening and overnight. The HRRR hints at the possibility of a isolated showers/tstms across the southern tier and Laurels Fri evening, but will cap POPs around 15% for now. Expect a milder Friday night with minTs trending +5F warmer than Thursday night with some patchy fog possible. Medium range guidance continues to indicate a return to more humid and unsettled conditions this weekend into early next week, as a deep southwest flow develops ahead of a slow- moving upper trough approaching from the midwest. Model consensus tracks increasing deep layer moisture with a lead shortwave moving into our region Saturday. This feature should produce a chance of showers over the western half of the CWA by late Saturday. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Scattered to numerous PM showers/tsra appear a good bet Sunday in high PW air mass with falling heights and upper level diffluence ahead of upper trough. Numerous showers/tsra will continue into Monday-Tuesday as the trough axis slowly approaches Pennsylvania. Peak coverage of rainfall will be each afternoon with daytime heating. An early guess at possible rainfall early next week based on ensemble plumes is around a half inch areal average, with localized amounts of over an inch. A stray shower or storm is possible Wed-Thu, but coverage should be significantly less as higher heights build in. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... At 03z, all of the shower activity has dissipated. The Nighttime Microphysics imagery is already showing extensive fog formation in the northern valleys, and BFD has recently dropped to IFR. Rainfall was not nearly as widespread today as it was yesterday, so we should not see quite the expanse of fog that we saw last night. Even so, fog is already forming in the northern valleys and should continue to expand overnight. Also expecting IPT to drop to IFR conds overnight, but less confident elsewhere. Hinted at the possibility of fog at UNV and AOO, but left it out of JST and the Lower Susq airfields for now. After any morning fog dissipates, Friday will feature sunshine, light winds, and widespread VFR conds. Outlook... Sat...Spotty -SHRA possible, mainly PM. Otherwise, VFR. Sun-Mon...More widespread SHRA/TSRA and reductions possible. Tues...Scattered -SHRA possible, mainly PM. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Steinbugl/Colbert NEAR TERM...Steinbugl/Colbert SHORT TERM...Steinbugl/Colbert LONG TERM...Steinbugl/Colbert AVIATION...Evanego
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
641 PM CDT Thu Aug 18 2022 ...New AVIATION... .SHORT TERM... (Tonight through Friday night) Issued at 147 PM CDT Thu Aug 18 2022 The anticipated weak frontal boundary is pushing across the Hill Country as of 2 PM. Area Doppler radars are showing a large area of scattered to numerous showers and scattered thunderstorms mainly affecting the northern and central portions of Llano, Burnet and Williamson Counties. A smaller area receiving beneficial rain is central and southeast Lee County. The weak frontal boundary is forecast to continue to push south for the rest of this afternoon and evening. The boundary becomes even weaker as it pushes along Interstate 10 and Highway 90 later tonight. Let`s break it down so you can have a better understanding of the projected weather forecast for the short term period. When looking at water vapor and visible imagery data, there are a couple of features of interest. First, the upper level long wave that covers the eastern two thirds of CONUS. Within it, several short waves are expected to push down from the Central Plains into the Southern Plains later today under the influence of a northwest flow aloft. The other feature is located to the south of Midland. This feature has a cyclonic flow while pushing to the southwest. It looked better a few hours ago but remains there. Now, let`s put all of this together. The weak frontal boundary is pushing across the Hill Country as of 2 PM. Temperatures ahead of the boundary are in the mid to upper 90s and up to 100 degrees with dewpoints around the mid to upper 60s to even lower 70s. RAP forecast soundings suggest MLCAPE ranging from 2000-3000 J/kg with moderate DCAPE around the 400 to 900 J/kg and pwats above 2 inches for this afternoon. In short, this is a recipe for the potential for strong to marginally severe thunderstorms to develop with locally heavy rain. The main severe weather hazard for this afternoon and evening is likely to be strong to damaging wind gusts of 40 to 60 mph. The other weather threat would be locally heavy rain with some locations expected to get from one half to one inch of rainfall across parts of the Hill Country, Interstate 35 including both Austin and San Antonio metros and the Coastal Plains. Can`t rule out isolated places getting from 2 to 3 inches of rainfall through the period as the front sits and slowly pushes to the south. With the loss of daytime heating, expect storms to be sub-severe for this evening as the frontal boundary weakens or dissipates. Remember, that feature above mentioned to the south of Midland? Hires models pick on it later this evening to bring a round of scattered showers and thunderstorms across the southern Edwards Plateau and the Rio Grande. Most of the activity comes to an end late tonight with lows in the 70s across most locations. The combination of a northwest aloft while a couple of disturbance drop down to our area and outflow boundaries from today`s convection will lead to more rain on Friday. With plenty instability expected and elevated pwats exceeding 2 inch values, locally heavy rain is in store for parts of the southern Edwards Plateau, Hill Country, Interstate 35 and the Coastal Plains. One half to one inch of rainfall is possible over the above mentioned areas but can`t rule out higher amounts. Highs are forecast to only reach the mid 80s to lower 90s. Saturday morning lows are expected to be in the 70s. && .LONG TERM... (Saturday through Thursday) Issued at 147 PM CDT Thu Aug 18 2022 A mostly dry weekend is in store with only spotty/isolated rains possible mainly for areas along/east of I-35, bookended by more widespread rain chances today/tomorrow (see short term for details) and then again next week. Locally heavy rains could be possible across the Hill Country Monday through Wednesday. Expect cooler temperatures for most of the long term as well, with forecast highs down into the mid 80s to mid 90s Tuesday through Thursday. Seasonal high temperatures are forecast for Saturday, with a low chance for a few showers and storms mainly for the Coastal Plains, but perhaps for the Llano/Burnet county area as well per the tail end of the 12Z WRF-FV3. Dry weather is likely to continue overnight and Sunday for the most part, but we`ll have to continue to watch the tropical disturbance currently over the Yucatan Peninsula. NHC continues to hold onto 30% chances for development into a Tropical Depression before it moves onshore somewhere near S TX late Saturday. Its likely to move pretty quickly northward, limiting the amount of time it will have to organize. But there does remain a low chance that, despite guidance struggling to develop anything notable, a slightly more potent rainmaker could impact portions of our region Saturday night into Sunday. Don`t fret, however, if you miss out on rains today through Sunday. Broadening negative height anomalies at the H5 level will slowly work their way south through the southern Plains and widespread shower and thunderstorm activity is expected to dominate the forecast through much of next week across central and northern TX. Rain chances will be highest across our CWA Monday night through Wednesday, and even southern portions of our region could get in on the action once again by Tuesday and Tuesday night. Currently, WPC QPF for our region Sunday night through Thursday evening calls for a quite welcomed 2-4+" north and 1-3" south. But I want to caution that this is towards the high end of the ensemble envelope per GEFS, uncertainty in the day 5-7 range remains moderate to high, and given the nature of summertime rains it is likely that some locations will see less (while some could potentially see more) than this forecast. Changes will occur over the coming days. && .AVIATION... (00Z TAFS) Issued at 641 PM CDT Thu Aug 18 2022 Morning low clouds and afternoon thunderstorms are the main aviation concerns for this TAF period, with VFR conditions prevailing otherwise. MVFR cigs are likely to develop at KDRT/KSAT/KSSF through the early morning hours tomorrow, lingering until around 17Z. There is less certainty in low cloud cover at KAUS so we`ve only mentioned SCT clouds for now. A lingering frontal boundary will once again be the source of scattered thunderstorm development Friday afternoon. KAUS has the greatest chance of seeing storms, which would occur primarily in between the 18-00Z timeframe. Storms may reach the San Antonio terminals by 21Z, possibly lingering through the evening. Winds will be mostly variable and light through the period due to the frontal boundary across the area, though strong and erratic wind gusts are possible in and around storms. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 75 91 75 98 / 40 70 10 20 Austin Bergstrom Intl Airport 74 92 74 96 / 40 70 10 20 New Braunfels Muni Airport 74 95 75 98 / 50 60 10 20 Burnet Muni Airport 74 90 74 94 / 40 60 10 20 Del Rio Intl Airport 77 96 77 96 / 30 30 10 10 Georgetown Muni Airport 75 91 75 96 / 50 60 10 20 Hondo Muni Airport 75 95 74 96 / 40 40 10 10 San Marcos Muni Airport 73 93 72 97 / 50 60 10 20 La Grange - Fayette Regional 73 94 73 97 / 50 60 10 20 San Antonio Intl Airport 75 93 75 96 / 50 60 10 20 Stinson Muni Airport 76 96 75 98 / 40 40 10 20 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Short-Term...17 Long-Term...KCW Aviation...Gale
National Weather Service Sioux Falls SD
1055 PM CDT Thu Aug 18 2022 .UPDATE... Issued at 640 PM CDT Thu Aug 18 2022 Expanded the Severe Tstorm Watch across much of the northwest Iowa as storms track east into a continually favorable environment based on RAP analysis of 0-6km shear of 40-50 kts and MUCAPE > 2000 ahead of the passing front. Further west where winds have turned northerly (near and west of I-29), severe weather threat has diminished for the night. && .SHORT TERM...(This Evening through Friday) Issued at 245 PM CDT Thu Aug 18 2022 A moderately strong jet max will dive south late this afternoon and evening helping bring a chance for showers and thunderstorms to the area. Early afternoon satellite shows what may be the mid level wave dropping south towards De Smet and Brookings with the surface cool front accelerating a little more quickly than expected towards I-29. Went ahead and decreased the chances for thunderstorms west of I-29 and especially near and west of the James River. The focus of this convection should be diurnal heating and frontal forcing which means the best time will be from about 5 pm to 9 pm today. Overall instability this evening is moderate, CAPE about 1500 J/kg, with the EML running about 7 to 7.5 degrees C. However the shear is pretty minimal so any severe threat should be very isolated with what will more than likely be some pulsy updrafts that collapse on themselves fairly quickly. While locally heavy rain will be possible the storms should not train and are not expected to move overly slow so not anticipating any flash flooding threat. PWAT values also about 1.25- 1.3 inches so not excessively high either. After this evening we may see a lull in showery activity until mid to late morning on Friday as the main upper level low drops south. The models are in good agreement in expanding the showery activity from north to south late Friday morning into the evening. Once again, heavy rain is not expected, but some locally higher amounts around an inch or inch and a half are possible. Overall, should be a cloudy and wet day Friday. Highs mainly upper 60s to mid 70s. .LONG TERM...(Friday Night through Thursday) Issued at 245 PM CDT Thu Aug 18 2022 The upper level low slowly shifts southeast on Saturday. Some residual showers will be possible, mainly in the morning. Otherwise gradual clearing and a north wind will keep temperatures a bit cooler, with highs mainly in the mid to upper 70s. Sunday into Thursday should be a quiet period of weather as a broad upper level ridge builds to the west and the area remains in a mild and dry flow regime. Overall highs will be in the 70s to lower 80s on Sunday, then mainly in the 80s Monday through Thursday. Lows should generally be from 55 to 65. The chances for rainfall will be small, but by Thursday there are some hints of some energy that could bring rainfall. && .AVIATION...(For the 06Z TAFS through 06Z Friday night) Issued at 1051 PM CDT Thu Aug 18 2022 Overnight VFR conditions will prevail with winds becoming light and northerly. May see areas of fog east of the I-29 corridor overnight but this does not look likely to affect TAF sites at this time. Another round of showers and isolated thunderstorms with MVFR ceilings is expected to spread in from the north Friday with gusty northwest winds. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...NONE. MN...NONE. IA...NONE. NE...NONE. && $$ UPDATE...BP SHORT TERM...08 LONG TERM...08 AVIATION...BP
Area Forecast Discussion
National Weather Service Gray ME
1005 PM EDT Thu Aug 18 2022 .SYNOPSIS... The low pressure system responsible for rain across the area will lift northeast tonight allowing high pressure to build in for Friday. This will result in much warmer and drier conditions. A warm and somewhat humid weekend is expected under partly sunny skies. Conditions look to turn somewhat more unsettled as we move into next week with chances for showers and thunderstorms returning to the forecast with temperatures returning back toward seasonal norms. && .NEAR TERM /THROUGH FRIDAY/... 1005PM Update...Surface dewpoints across southern NH are running a little higher than what was previously in the forecast, so have nudged those upward over the next few hours, closer to what the HRRR is depicting. Otherwise, the overall forecast looks good with shower coverage continuing to diminish through this evening and tonight as the low pressure pulls north away from New England. 630PM Update...Despite there being a few echoes showing up on radar across southern NH, the low levels look to have dried enough to where only a brief sprinkle or two may reach the ground at this point. So, have cut back PoPs across this area with the majority of the shower activity remaining confined to the mountains, foothills, and those slightly downstream. Previous discussion... High Impact Weather Potential: Minimal. Pattern: Large upper low dominates early afternoon water vapor imagery with a vertically stacked low pressure system over northern Maine slowly beginning to lift north and east away from northern New England. The weakening/departing low has yielded gradually improving conditions with shower activity slowly weakening. This improving trend will continue through tonight as high pressure begins to build towards the region from the south and west. Primary forecast focus will be on lingering showers and any potential for fog given moist surface conditions. Through this evening: Showers continue to pinwheel around decaying surface low...but have weakened and decreased in coverage since this morning. Still...scattered to numerous showers will continue into the evening hours given moist...cyclonic boundary layer flow. Temperatures at 8pm will range from 60 over the mountains to the mid/upper 60s to the south. Tonight: Mid level height rises continue across the region under northwest flow aloft as low level cyclonic flow slowly releases it/s grip. Scattered showers will be ongoing this evening...but will gradually become increasingly confined to the upslope regimes before ending. Overnight...skies will partially clear with light westerly winds continuing. Lows should fall into the 50s for most spots. Given the recent rainfall and partial clearing...some valley fog will be possible...with overnight lows near crossover values. Have included patchy fog mention across the north and down the CT Valley. && .SHORT TERM /FRIDAY NIGHT/... High Impact Weather Potential: Minimal. Pattern: Flow aloft will back and heights will build as trough and associated surface low continue to lift north and east away from the region. High pressure will build towards the region from the south and west through Friday night with a quiet period of weather expected. Friday: Lingering cyclonic flow may be enough to allow for a morning sprinkle in the upslope regime but otherwise...the drying llevel airmass suggests a partly to mostly sunny day as high pressure builds in from the west. Review of model sounding and plan view progs suggest dewpoints will fall into the 50s...though the core of the driest air looks to reside over southern New England which saw much less in the way of rainfall over the past 36 hours. T8s will be pretty warm...around +14C which should allow SE NH and SW ME to rise into the upper 80s with middle 80s elsewhere south of the mountains...and temperatures in the 70s in the mountains where temps aloft will be cooler and there will likely be a few more clouds. Friday Night: Quiet and comfortable night as high pressure ridge axis will be overhead in the presence of a reasonably dry boundary layer airmass. This should allow for mostly clear skies...light winds and temperatures to fall into the 50s for most locations... closer to 50 in the northern valleys...and closer to 60 for ASH-MHT- PSM-PWM...which is closer to the statistical guidance and a bit below the National Blend of Models. && .LONG TERM /SATURDAY THROUGH THURSDAY/... High pressure over the Atlantic will spread to the northwest Saturday bringing warm temperatures for the weekend. Clear skies Saturday will allow temperatures to rise into the mid to upper 80s south of the mountains with some southern/valley locations reaching near 90 degrees. Humidity will gradually increase over the weekend as well with dewpoints in the low 60s expected Saturday, rising into mid 60s Sunday and Monday. Clouds will start increasing over the day Sunday as low pressure starts drawing nearby. Unsettled conditions move in for the start of next week with a few shortwaves creating some chances for precipitation by midweek. Low pressure, currently over the southern US, will slowly make its way up the east coast over the weekend bringing cloudier and more humid conditions to the north. At the same time, an upper level low will slowly make its way east across the Great Lakes with both systems making their way into New England on Monday. The combination of these two systems will bring unsettled conditions to the area for the first part of next week. Ensemble cluster analysis is showing better agreement on showers moving in from the southern system Monday afternoon before filling in to the west and north as the system from the Great Lakes moves in overnight. QPF amounts and timing of heavier showers/precip is still uncertain. Cluster analysis is still a mixed bag for Tuesday with roughly equal chances for wetter and drier solution. Generally the GFS and CMC are in better agreement on a wetter/more northern solution than the ECMWF and have been more consistent on the dynamics. Ensemble members aren`t picking up on a main organized low developing over these few days of unsettled conditions, however that could easily change with future model runs. The general model trend is making me lean towards the GFS/CMC solutions which would bring a 48 hour period of wetting rains to the area but I am still keeping precip at a chance until areas of heavier rainfall are more certain. Winds turn to the northwest Thursday with some upslope showers lingering through the day before another chance of precipitation moves up the east coast to New England for the end of the week. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Short Term... Summary: Low pressure just east of the region will lift away from the area tonight with gradually improving conditions as high pressure arrives from the south and west. Restrictions: Variable conditions across the terminals at the moment with MVFR continuing over much of western ME but improvement to VFR having occurred over southern NH. Scattered showers will continue into this evening before coming to an end with overall improving conditions expected. Expect all sites to be VFR by 00Z Friday with some overnight fog bringing IFR/LIFR at HIE-LEB. VFR conditions expected Friday with valley fog potentially impacting both HIE/LEB again Friday night. Winds: Northwesterly winds 10g18kts will diminish to less than 10kts overnight...returning back to around 10kts for the day on Friday. Winds will go calm/light-variable Friday night. LLWS: No LLWS is expected through Friday night. Lightning: No lightning is expected through Friday night. Long Term...VFR conditions prevail through the weekend with southwesterly winds before unsettled conditions move in for next week. Overcast and lower ceilings will linger through midweek with MVFR/IFR restrictions possible within showers. && .MARINE... Short Term...With low pressure pulling away from the region...westerly winds and waves will continue to subside through the short term period with no additional headlines expected. Long Term...Winds and seas will continue to be below SCA thresholds through the weekend and into next week as high pressure sets in and winds turn from the southwest. Unsettled conditions move in for the first part of next week with a chance of showers Mon-Wed. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ UPDATE...Combs SYNOPSIS...Arnott NEAR TERM...Arnott SHORT TERM...Arnott LONG TERM...Thunberg AVIATION...Arnott/Thunberg MARINE...Arnott/Thunberg
Area Forecast Discussion
National Weather Service Key West FL
1028 PM EDT Thu Aug 18 2022 .DISCUSSION... Currently - A broad mid latitude trough over the eastern United States is holding the weak western flank of the Atlantic ridge across our area. This, along with day time heating over the mainland is resulting in northwest winds over our western reaches and southwesterly to the east. This evenings sounding indicated no inhibition, seasonably ample CAPE and precipitable water. Despite this, the lack of large scale forcing and slow advection has resulted in little to no shower and thunderstorm coverage. The main exception to this has been late afternoon reverse cloud line activity in the vicinity of the Lower Keys and weak confluence over our gulf waters. Short Term Update - The mid latitude trough will remain over the eastern United States through the overnight period. However, a subtle lifting of the eastern flank of this broad trough will allow the Atlantic ridge to advance northward into South and Central Florida. Consequently, light surface winds will gradually shift southeasterly. While global models have very low pops for overnight, the HRRR does see isolated activity developing towards morning. The latter appears more reasonable, due to the usual increased confluence brought about by the wind shift approximately around the time of peak nocturnal confluence. For now, will maintain slight chance PoPs. The lack of inhibition, ample moisture, and CAPE also justifies keeping thunder in. No changes made in the evening marine update. Overnight lows will approach 80 degrees, with dew points holding in the mid 70s. && .MARINE... A ridge across the Keys will lift northward into South and Central Florida overnight. As a result, light breezes will shift southeasterly. Only minor adjustments made to first period wind transition phrasing in the evening marine update. && .AVIATION... VFR conditions will prevail through 19/15Z. However, late tonight nocturnal showers may develop near the terminal sites and persist through early Friday morning. Winds will be light and variable, then becoming east to southeast and increasing to near 10 knots by 19/15Z. && .CLIMATE... On this date in 1926, the daily record rainfall of 8.32 inches was recorded in Key West. This is the second wettest day on record in August. && .PRELIMINARY POINT TEMPS/POPS... Key West 81 90 83 90 / 10 20 30 40 Marathon 81 93 82 93 / 10 20 30 40 && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...11 Aviation/Nowcasts....TW Data Acquisition.....DR Visit us on the web at Follow us on Facebook and Twitter at:
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 338 PM CDT Thu Aug 18 2022 A shortwave trough over the eastern Dakotas and western Minnesota will continue deepen and drop south into northern Iowa overnight. Ahead of this, a surface cold front continues to drop southeast into northeast Nebraska this afternoon. It is forecast to stall a bit this evening before pushing through the entire forecast area overnight. Isolated severe storms are possible late this afternoon into the early evening hours near the boundary as it moves into a moderately unstable environment currently in place over northeast Nebraska. Surface temperatures ahead of the front have warmed into the upper 80s to around 90 in many locations. On top of cooling mid-levels, mid-level lapse rates continue to steepen across northeast Nebraska. 0-6km bulk shear remains around 35kts with 0-8km around 50kts off the SPC meso page. This environment is supportive of discrete supercells mainly capable of damaging wind gusts and large hail. The CAMs remain in good agreement of timing with 4pm-8pm still the main severe time-frame. Showers may linger overnight as they approach I-80 after 03z but severe threat is expected to wane after sunset. Depending on where the front stalls, another round of potentially active weather is possible for areas south of I-80 on Friday. The HRRR has started to pick up on thunderstorm development mid-afternoon Friday along I- 80, some of which could be severe. A warming trend is forecast as we move into early next week as upper- level ridging builds to our west. Highs look to be primarily in the 80s for most areas. No significant precipitation is forecast during this time. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 554 PM CDT Thu Aug 18 2022 Frontal boundary currently moving southward through eastern NE kicking off a few TSRA. Expect storms to move through KOMA/KLNK sometime between 00Z-02Z. Front will linger in the vicinity of the TAF sites through Friday and will be the focus for another round of TSRA activity by Friday afternoon. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Kern AVIATION...DEE