Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/24/19

Area Forecast Discussion
National Weather Service Austin/San Antonio TX
1013 PM CDT Fri Aug 23 2019 .UPDATE... Finally had enough clarity to update the forecast for the rest of the night through 12Z Saturday. A combined sea-breeze and outflow from storms on the coastal plains pushed all the way to the Edwards Plateau and Rio Grande Plains late this evening. This has re- invigorated convection, but already the bump seems to be past the peak and we expect convection to decrease over the next few hours. That said, areas with storms in the vicinity now can expect a bit more rain before midnight, then a fairly quick tapering off. Otherwise, the rest of the forecast is in good shape, but we still re-trended hourly variables through 12Z. && .PREV DISCUSSION... /ISSUED 653 PM CDT Fri Aug 23 2019/ UPDATE... 00Z Aviation forecast below. AVIATION... Isolated to scattered SHRAs and TSRAs ongoing across portions of South Central Texas this evening. Activity near and east of the I-35 corridor should diminish after sunset. Convection across portions of the Hill Country and near the Rio Grande could persist longer into the evening, before diminishing overnight. A few storms could produce gusty winds. In addition, outflow from earlier storms, combined with the sea-breeze boundary, is racing inland and producing strong wind gusts at AUS, HYI, and BAZ and should arrive at SAT very shortly. Wind gusts between 25-40 kts have been recorded with this boundary. Outside of convection VFR conditions will prevail through the evening and most of the overnight. A small area of MVFR ceilings may occur between 09Z-15Z near the I-35 corridor. PREV DISCUSSION... /ISSUED 250 PM CDT Fri Aug 23 2019/ SHORT TERM (Tonight through Saturday Night)... Early afternoon water vapor imagery showed a few larger scale features around the continental US with a compact upper low spinning over Montana, Wyoming, and Idaho and a shortwave trough axis located over the northwestern Gulf of Mexico. Additionally, regional VAD wind profilers indicate that the mid-level trough that was evident over West Central Texas on this morning`s radiosonde observations is still lingering over West Central Texas. Visible satellite imagery has shown an enhancement in the cumulus field in the vicinity of this feature. Continued heating combined with weak lift from this trough and residual surface boundaries from last night`s thunderstorms will allow for deeper updrafts to develop through the remainder of the afternoon hours and into the early evening. This will result in rain chances focusing in two areas this afternoon: the Hill Country and parts of the Rio Grande Plains, which are closer to the trough, as well as the Coastal Plains as the sea breeze moves inland. Surface dew point depressions around the region are close to 25 to 30 degrees this afternoon and this relatively dry sub-cloud airmass will mean that any strong thunderstorm will be capable of a gusty wind threat. GOES Total Precipitable Water satellite imagery shows that precipitable water values range from 1.6 to 1.9 inches across the region this afternoon in a weakly sheared environment and thunderstorms will also be slow-moving and capable of locally heavy rain. Regional radars shows a southward-moving outflow boundary nearing the Interstate 20 corridor as well, which a few HRRR runs have indicated may reach Central Texas before midnight tonight. Only carrying a silent 10 percent chance of rain for this feature, but a mid-evening update to increase rain chances for the Central Texas counties may be needed should it hold together. Otherwise, storms may linger into the the early morning hours across Val Verde County given the proximity of the mid-level trough with a few streamer type showers edging into the Coastal Plains by dawn. Redevelopment of nocturnal stratus will again keep overnight lows elevated in the low to mid 70s. Broad mid/upper-level ridging spreads across California into the Desert Southwest tonight as the weak mid-level trough axis remains centered over Texas. As the closed low near Montana opens up and crosses the Central Plains during the day Saturday, the weakness over Texas gets pushed east of the region and and allows for ridging to begin spreading back into the state Saturday night. This will mean that isolated to scattered showers and thunderstorms will be possible across most of the region during the late morning through early evening hours on Saturday as convective temperatures are reached, with greatest coverage along mesoscale boundaries either leftover from storm`s today or the sea breeze. Forecast soundings continue to indicate an inverted-V profile, indicating stronger cells on Saturday will once again be capable of gusty winds. While a few storms may linger into the evening hours Saturday across the Rio Grande Plains, loss of heating will allow for most activity to dissipate with lows again in the low to mid 70s. LONG TERM (Sunday through Friday)... With mid-level ridging building back into the region on Sunday, temperatures will gradually get hotter Sunday through the mid-week period. This will also suppress rain chances across most of the region save for the sea breeze as it reaches the Coastal Plains. A series of troughs crossing the Central Plains late week may attempt to send a cold front into North Texas by late in the forecast, but inconsistencies amongst medium range guidance precludes introducing any kind of significant changes to the temperature or rain forecast late week. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 77 97 78 99 78 / 20 20 10 20 10 Austin Bergstrom Intl Airport 75 95 77 98 78 / 20 20 10 20 10 New Braunfels Muni Airport 75 95 76 98 77 / 20 20 10 20 10 Burnet Muni Airport 74 95 75 98 76 / 20 20 10 20 10 Del Rio Intl Airport 78 98 78 102 79 / 30 30 20 10 0 Georgetown Muni Airport 76 97 77 99 78 / 20 20 10 20 10 Hondo Muni Airport 76 99 76 100 77 / 10 30 20 20 10 San Marcos Muni Airport 75 96 76 98 77 / 20 20 10 20 10 La Grange - Fayette Regional 76 97 77 98 78 / 20 30 10 30 10 San Antonio Intl Airport 77 97 78 98 79 / 20 20 10 20 10 Stinson Muni Airport 77 97 78 98 79 / 20 20 10 20 10 && .EWX WATCHES/WARNINGS/ADVISORIES... None. && $$ Aviation...Runyen Short-Term/Long-Term...Zeitler
Area Forecast Discussion
National Weather Service Memphis TN
729 PM CDT Fri Aug 23 2019 .UPDATE... Updated to lower rain chances across the north tonight. && .DISCUSSION... Radar trends are showing a gradual decrease in storm coverage this hour...with no activity currently across the northern two thirds of the County Warning Area. Have lowered rain chances this evening and later tonight in this region...with the southwest delta counties favored for continued overnight activity. JAB && .PREV DISCUSSION... /issued 648 PM CDT Fri Aug 23 2019/ DISCUSSION... /issued 301 PM CDT Fri Aug 23 2019/ Main story this forecast is the continued unsettled pattern across the Mid-South, with periods of showers/storms. Pinpointing timing and location of most concentrated precip will be challenging given generally weak flow and features. Diffuse surface front should move south into our southern counties today. Guidance is consistent in bringing a weak upper system across the area tonight and Saturday. With moist airmass and fairly light winds, will add patchy fog toward daybreak Saturday. Lift from upper system and focusing of surface front should result in greatest precip coverage south of I-40 corridor tonight and Saturday. System should move east of CWA Saturday evening, with lower precip chances Saturday night. Another weak system to move across the Mid-South Sunday. A somewhat stronger disturbance associated with upper low over MO/IA should move across the area by Sunday evening, bringing another round of precipitation late Sunday and Sunday night. Monday-Wednesday, Mid-South will be under generally broad WNW flow aloft. The series of weak upper systems will continue, with GFS and ECMWF showing disturbances moving across the area every 18 hours or so. By Thu-Fri, both ECMWF and GFS amplify the NW flow aloft and bring a cold front through the area with drier air moving in. GW && .AVIATION... 00Z TAF Set An outflow boundary from convection occurring across N MS may move through KMEM around 01Z. Some convection has developed behind the boundary. The HRRR continues convection through 06-7Z. For now will just continue with VCSH wording through 07Z. Models still show some IFR conditions spreading into the Mid-South between 09-12Z. New convection will then start developing around 18-19Z with the HRRR focusing development near the MS/TN border. For now will continue VCTS wording at KMEM, KMKL, and KTUP. Winds will remain out of the NE at 5-10 KTS through period. Although, speeds may diminish during the overnight hours. KRM && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
936 PM EDT Fri Aug 23 2019 .SYNOPSIS... A cold front will approach the area tonight and slowly cross the region Saturday. The front will stall well offshore Sunday with low pressure moving along it Monday. Another cold front will approach the area mid to late week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 930 PM Friday...Convection has focused across the nrn tier just ahead of front as expected. Instab is diminishing and this shld end severe threat...however locally very heavy rain will cont for at least next few hrs with flood threat. Did signif lower pops srn tier for next few hrs as will only see some sprinkles from mid lvl debris clouds. Convection may spread S late tonight with front however HRRR show little remaining late. Prev disc...Immediate next few hours are expected to be mainly dry with a few afternoon showers and storms possibly sneaking into the coastal plain. Main event is later tonight as the front sinks south and storm coverage increases in an axis of 30-35 knot 0-6 km bulk shear across the NC/VA border and MLCAPEs approaching 2500 J/kg. All the hi-res guidance indicates a squall line developing and stalling along the VA border before progressing south after sunset as the convective system becomes gradually cold-pool dominant. Main concern is minor/urban flooding with PWATs of 2-2.25 inches, but current thinking is line will be moving fast enough to preclude more widespread flash flooding. A risk for gusty to severe winds with the squall line is possible mainly for our northern tier of counties. Overall precipitation chances drop to the south with much weaker shear and lack of daytime heating. Have categorical PoPs northern tier to high chance along the Crystal Coast. Highs remainder of today top out in the low 90s with cloud cover keeping lows in the mid 70s along the coast, to low 70s inland with the aid of cooling rainfall. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH 6 PM SATURDAY/... As of 300 PM Friday...Front continues to push south towards the coast on Saturday with plenty of cloud cover lingering in its wake. Behind the front, high pressure to the north will shift east and set up a weak wedge/cold-air dam to our west, aiding in cooler and more stable air. A thin axis of instability is possible along the coast as hinted by hi-res guidance, but given the expected considerable cloud cover I have my doubts if there will be enough instability to sustain as aggressive of coverage as advertised. If more sustained activity is realized storm motions will be slow in an axis of 2-2.25 inch PWATs suggesting a localized flooding threat, especially considering the recent substantial rainfall these areas have received. Due to uncertainty in storm evolution, nudged PoPs down from categorical to likely. With the wedge and plenty of cloud cover lows tomorrow will be considerably cooler with low to mid 80s along the coast, upper 70s in the northern coastal plain. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... As of 345 PM Fri... Periods of unsettled weather continues Sunday and possibly into Monday. Another cold front will approach the area from the west by midweek. Saturday Night...Cold front will push offshore by Sat night. As the front pushes south, a weak/shallow high pressure wedge builds in to the Carolinas. Fairly widespread showers will continue through the evening, as decent overrunning regime sets up with H85 mb flow still srly. PW values are above 2.00" and deep warm cloud layer with the best convergence near the low/mid level frontal across srn half of the FA. Sunday through Monday...Continued following the more consistent ECMWF, as has support from the UKMET/CMC with a more developed, albeit further offshore, tropical system. The GFS appears to remain an outlier with a near-coast and much weaker tropical or subtropical system. With expected further offshore track, impacts would be relegated to the waters in the forms of high surf and strong rip currents. Gusty winds will be felt along the coast due to high pres ridging into the Carolinas and low pres gathering to the south. More unsettled weather possible for Sunday, though coverage and intensity does not appear too impressive, so rain amounts do not look too high, even along coastal areas. Will retain likely pops for coastal zones with chc pops interior as ocnl showers will be a threat at any time during the day. The low will pass well east of the NC coast on Monday, keeping only chc showers in the fcst, and breezy conditions on the coast due to gradient between high pres ridging in from the west and the low well offshore. Tuesday through Thursday...High pressure should build back in Tue with more drier conditions, then an approaching cold front by midweek resulting in sct showers and thunderstorms. Expect highs to climb back towards climo, in the mid/upr 80s. Lows continue in the 60s interior to low 70s coast. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... Short Term /through Saturday/... As of 645 PM Friday...VFR conts and shld thru evening outside poss brief sub VFR if shra/tsra impact a terminal. Later tonight as front pushes thru most of guidance suggests IFR cigs develop N to S after 06Z that will cont thru Sat Morn. Later Sat have cigs lifting a bit to MVFR but confidence low as IFR could persist in the moist NE flow. Numerous shra and a few tsra expected to develop again Sat as well. Long Term /Saturday night through Tuesday/... As of 345 PM Fri...The frontal boundary will remain close to the NC coast and continue bring unsettled weather Sat night and into Sun, with ocnl sub VFR expected. Some drier air moves in by the beginning of the week leading to improved flying conditions. && .MARINE... Short Term /Tonight and Saturday/... As of 930 PM Friday...Strong SW winds ahead of front over mainly Pamlico Sound are finally showing signs of diminishing. This trend shld cont as front slowly pushes S into the area overnight. Prev disc...Seas this hour 2 to 3 feet except for more persistent 4 foot seas in the outer waters with SW winds at around 10 to 20 knots. A cold front will approach the northern waters tonight with SW winds at around 15-20 knots with a few gusts to 25 knots, although nothing widespread enough to warrant SCA. Winds gradually shift to the N and then NE through Saturday as the front slowly pushes offshore. A weak surge of N/NNE winds mainly for the northern waters and sounds at around 15 knots is expected Saturday afternoon and evening. Long Term /Saturday night through Tuesday/... As of 345 PM Fri...A cold front will be south of the waters by Sat night. Winds increase out of the NE on Sunday and should reach SCA conditions with sustained 20-25 kt NE winds due to high pres from the west and developing low pres well offshore. The gusty NE winds continue on Monday as potential tropical or subtropical storm moves NE well off of the NC coast. Seas and swell will build to greater than 6 ft by Sunday and remain that way through Monday as the system tracks NE. WWIV much too low with the waves so relied more on the ECM waves and NWPS. Winds and seas start to subside later Monday through Tuesday as the system moves well away from the waters. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...RF/MS SHORT TERM...MS LONG TERM...TL AVIATION...RF/TL MARINE...RF/TL/MS