Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/15/17

Area Forecast Discussion
National Weather Service Charleston SC
943 PM EDT Sat Oct 14 2017 .SYNOPSIS... High pressure will continue north of the area through Sunday. A cold front will move through the region Monday. High pressure will build north of Georgia and the Carolinas through mid week and persist into late week. && .NEAR TERM /UNTIL 6 AM SUNDAY MORNING/... GOES-16 fog channel and 15/01z surface observations show shallow ground fog beginning to develop across the southern Pee Dee into portions of Berkeley County and upper Charleston County. So far, RAP and H3R vsby guidance is doing a decent job and matches the going forecast pretty well. Updated the Hazardous Weather Outlook to highlight the potential for dense fog across inland areas. Lowered overnight lows by several degrees across parts of the Charleston Tri-County area into northern Colleton County where temperatures were already approaching the previously forecasted minima. Temperature falls should level out in these areas as saturation occurs and stratus begins to develop. Could see a few upper 50s in the normally colder areas of the Francis Marion National Forecast. The remainder of the forecast is on track. The primary forecast concern for the overnight period centers on the potential for fog, especially inland. The boundary layer is poised to decouple shortly after sunset as high pressure shifts east to the North Carolina coast. Guidance suggests a weak gradient may linger across far southern areas to keep the boundary layer coupled there through at least midnight, but expect all areas to go either calm or calm for much of the early morning hours Sunday. Low-level moisture will pool beneath the noctural inversion with boundary layer saturation expected. With skies remaining clearing until late, expect areas of fog to develop away from the coast. NAM12 soundings suggest there may be just enough flow atop the boundary layer to support more in the way of stratus versus fog, but the RAP soundings suggest a slightly weaker flow will prevail thus favoring more in the way of fog. Suspect the ultimate outcome will fall in between the two with a mixture of fog and stratus encompassing much of the interior by daybreak Sunday. Will continue to highlight areas of fog inland with patchy fog at the coast. The best chances for dense fog look to setup across interior Southeast South Carolina from roughly Walterboro to Moncks Corner which is where the lowest 1000 hPa condensation pressure deficits are progged to occur. Lows will range from the lower 60s well inland to the lower 70s along the Georgia coast where onshore winds will help moderate temperatures. && .SHORT TERM /6 AM SUNDAY MORNING THROUGH TUESDAY/... Sunday: The expansive upper ridge will begin to narrow but another day of dry and warm weather is on tap across the forecast area. The synoptic flow will gradually trend from the broad wedge pattern from Saturday to a transitional/variable setup on Sunday. Pockets of stratus and fog are expected to dissipate by late morning leading to another unseasonably warm mid October afternoon across the area. Diurnal cumulus fields will probably be a bit more prevalent in southeast GA given the weak onshore component atop the boundary layer. High temps are expected to reach the mid 80s most areas inland from the beaches and barrier islands with some upper 80s not out of the question in a few spots that may see near-full sunshine. A progressive shortwave will push a cold front through the area on Monday. Moisture will briefly surge ahead of the front with PWATs above 1.75" on Monday. The latest model progs suggest convective rains will shift east and southeast along and just ahead of the cold front with likelihoods for showers and a few thunderstorms by late morning across the northern and inland zones and across the remainder of the forecast area during the afternoon hours. Rainfall amounts will generally average 1/4" or so, perhaps some heavier bands of 1/2" to 1" rains may occur. The arrival of the front will induce some strong thermal gradients across the region with temps falling through the 60s northwest zones by the afternoon while readings in the lower 80s will linger southeast zones until convective rains arrive mid to late day. Cooler and much drier air will spread into the area Monday night into Tuesday. Tuesday morning lows will be in the 50s and the highs will top out in the mid 70s. High pressure will prevail on Wednesday with highs again in the mid 70s with persistent northeast breezes. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... A large surface high will remain to the northwest during the extended period, maintaining dry conditions and slowly moderating temperatures. A few showers will be possible over the coastal waters and immediate coast as a weak coastal trough develops. && .AVIATION /02Z SUNDAY THROUGH THURSDAY/... Primary concern: * Fog and low-stratus yielding IFR or lower conditions Conditions look favorable for low stratus and fog to develop across the region early Sunday as high pressure holds firm. The best fog/stratus probabilities look to occur just inland from the terminals, but guidance is similar in showing KCHS positioned right along the eastern fringe of the lowest conditions. Will show prevailing MVFR in ground fog beginning around 09z with a TEMPO group from 10-12z highlighting vsbys just below alternate minimum thresholds. Opted to keep skies VFR with a scattered deck 200-400 ft. It is very possible that low cigs could become established and could approach airfield minimums, but confidence in this is not high enough to mention right now. For KSAV, looks like the best stratus/fog potential will remain west, so will only show high- end MVFR vsbys at this time with no cigs. Low cigs/vsbys should return to VFR by mid- morning and prevail through the remainder of the 00z TAF period. Extended Aviation Outlook: Areas of fog/stratus are possible Monday morning, resulting in MVFR/IFR visibilities and/or ceilings. Brief flight restrictions possible Monday afternoon in convective and post- frontal rains. && .MARINE... Tonight: No highlights. A ridge of high pressure will be centered just north of the waters. East-Northeast winds of generally 5 to 10 knots with seas 2 to 4 feet. Quiet conditions will persist Sunday into Monday morning before a strong cold front sweeps through Monday afternoon and evening. A strengthening northeast flow behind the cold front will likely result in a prolonged period of Small Craft Advisory conditions from Tuesday through much of next week. Strong moisture and thermal gradients will develop several hours around daybreak on Tuesday morning and pinching gradients may result in at least occasional gale force wind gusts off the GA coast beyond 20 NM. Seas will build to 4-6 ft with 7-9 ft seas likely beyond 20 nm off the coast Tuesday into mid-week. Seas may reach 10-11 ft out close to the Gulf Stream during Tuesday. && .TIDES/COASTAL FLOODING... Minor coastal flooding will be possible around the times of high tide beginning Tuesday morning. Coastal Flood Advisories could eventually be needed, especially along the South Carolina coast. && .CLIMATE... Record Highs for October 15th: KCHS: 87 set in 1985. KCXM: 88 set in 1925. KSAV: 90 set in 1925. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$
Area Forecast Discussion
National Weather Service San Angelo TX
912 PM CDT Sat Oct 14 2017 .DISCUSSION... Cold front moved through Amarillo around 9 PM, with gusts over 40 mph at times behind it in the Panhandle. HRRR short range model appear to be on track, moving the front through Sweetwater and Abilene between 2 and 3 AM...San Angelo and Brownwood just after 4 AM...and the I-10 corridor between 6 and 7 AM. North winds of 25 to 30 mph with higher gusts indicated after frontal passage support the wind advisory from 1 AM to 7 AM for the Big Country and Concho Valley. && .PREV DISCUSSION... /issued 655 PM CDT Sat Oct 14 2017/ AVIATION... /00Z TAFS/ A strong cold front will move across the terminals from north to south overnight, bringing gusty north winds and some scattered convection along and behind the front through the morning hours. Frontal passage is expected at the northern terminals between 07Z and 08Z and across the southern terminals between 10Z and 11Z. North winds will gust to around 30 knots behind the front through early afternoon, with winds slowly subsiding towards the end of the forecast period. Expect some MVFR ceilings behind the front Sunday morning, with VFR conditions returning by Sunday afternoon. PREV DISCUSSION... /issued 330 PM CDT Sat Oct 14 2017/ SHORT TERM... (Tonight and Sunday) Expect colder temperatures, windy conditions and a chance of rain late tonight through Sunday. A strong cold front will move south across West Central Texas, arriving at the I-20 corridor around 07Z and south of the I-10 corridor by 13Z. Strong north winds will occur behind the front with gusts to around 40 mph across the Big Country and Concho Valley, and a Wind Advisory is in effect for these areas from 1 AM to 7 AM Sunday. The winds should remain below advisory criteria across the remainder of the area, but will be quite gusty at times. Still will be windy through mid morning Sunday, and then speeds decrease during the rest of the day. Temperatures will be much cooler Sunday(at least 20 degrees) due to low level cold air advection. For precipitation, the Hi Res models are indicating a line of showers and thunderstorms will form along and just behind the front across much of the the area late tonight through Sunday morning. The best chance of storms will be across the northern half of the area due to better upper support and some elevated instability. The storms will produce dangerous lightning and strong wind gusts. The Highest Pops(Cat to Lkly) across the northern half of the area for late tonight. Most of the precipitation should end by 18Z Sunday. LONG TERM... (Sunday Night through Saturday) The of surface high pressure, a dry air airmass and mostly clear skies will bring cool temperatures to the area Sunday night through Tuesday. Lows will be mainly in the 40s Monday and Tuesday mornings, with a few upper 30s possible especially in low lying areas and river valleys. Highs will be in the 70s. A warming trend will take place mid to late this week across the area as low level southerly flow returns. Highs will be in the lower to mid 80s, with lows in the 50s, lower 60s by Friday and Saturday. Also, going with a mainly dry forecast. && .PRELIMINARY POINT TEMPS/POPS... Abilene 54 67 43 70 / 80 20 0 0 San Angelo 56 68 43 73 / 60 30 5 0 Junction 61 71 45 73 / 30 40 5 0 Brownwood 57 68 44 72 / 70 30 0 0 Sweetwater 52 67 45 69 / 70 20 0 0 Ozona 57 66 44 72 / 40 30 5 0 && .SJT WATCHES/WARNINGS/ADVISORIES... Wind Advisory from 1 AM to 7 AM CDT Sunday for Callahan-Coke- Concho-Fisher-Haskell-Irion-Jones-Nolan-Runnels-Shackelford- Sterling-Taylor-Throckmorton-Tom Green. && $$ 99/04
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Sunday) Issued at 258 PM CDT Sat Oct 14 2017 19Z water vapor imagery shows an upper trough over the central Rockies moving towards the NEB panhandle. At the surface, a trough axis extends from near SLN to MYZ and a cold front was located from HLC to HSI. Objective analysis from the RAP and LAPS shows some surface based instability of 1500 to 2000 J/kg has developed across east central KS, generally southeast of an EMP to TOP line. All the guidance shows thunderstorm coverage increasing along the front as it surges southeast through the area. Unidirectional wind shear and strong winds aloft continue to support the potential for damaging winds with the thunderstorms later this afternoon and this evening. So will need to keep an eye on severe potential. Current convection over east central KS could have a big impact on where the stronger storms develop. Based on some of the convective allowing models, the window for strong or severe storms looks to be from around 5 pm through about 9 pm. Precip will come to an end shortly after the frontal passage as much dryer and cooler air advects southeast. Winds are also going to strengthen behind the front with gusts up to 35 MPH possible across north central KS this evening. Thought about a possible wind advisory, but RAP and NAM progs of the pressure gradient force suggest the stronger winds should not last but for a few hours. And most objective guidance shows most areas remaining below criteria. So will not issue a wind advisory at this time and monitor conditions as the front moves through. Lows are expected to be in the lower to mid 40s. Continued cold air advection through Sunday is expected to keep highs in the lower 60s on Sunday. Although full insolation and relaxing winds will make it feel a little better. .LONG TERM...(Sunday night through Saturday) Issued at 258 PM CDT Sat Oct 14 2017 Surface high pressure over the Central Plains on Sunday night moves off to the southeast on Monday and remains over the southeast into the southern Plains keeping the gulf moisture off shore. Northwest mid level flow aloft on Monday then continues across the central Plains into mid week then transitions to southwest flow by then end of the week. Models move an upper trough off the eastern Pacific and into the Rockies on Saturday. There are some model differences with the timing and the strength of the trough next weekend so confidence is not high with precipitation chances. With return flow from mid week onward low level moisture will increase through the end of the week with dew points increasing into the mid 50s by Saturday. High temperatures for the week start out around normal on Monday with highs in the lower 70s on Monday warming up into the mid 70s for much of the week and into the upper 70s on Friday. Lows will start out Monday morning in the upper 30s, then in the 40s through Thursday morning with lows in the 50s for Friday and Saturday morning. Will monitor potential for Monday morning for some patchy frost in sheltered areas possible if temperatures are able to cool a few more degrees under good radiational cooling conditions. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 641 PM CDT Sat Oct 14 2017 FROPA past KMHK while boundary is hovering near KTOP/KFOE with westerly winds increasing and veering to the northwest. Kept a mention of VCTS at KTOP/KFOE given the proximity of the front through 02Z and the current convection to our south and southwest. Post frontal MVFR stratus builds in behind the boundary as strong northwest winds gust in excess of 25 kts through 09Z. Dry air advection is progged to erode stratus quickly before 12Z with VFR prevailing for the remainder of the period. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Wolters LONG TERM...53 AVIATION...Prieto