Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/29/17

Area Forecast Discussion
National Weather Service Bismarck ND
932 PM CDT Sat Oct 28 2017 .UPDATE... Issued at 932 PM CDT Sat Oct 28 2017 Temperatures slow to cool thanks to cloud cover and a steady mixing wind. Adjusted hourly temperatures based on latest observations, though overall I kept forecast mins roughly unchanged. UPDATE Issued at 657 PM CDT Sat Oct 28 2017 ESRL HRRR and other high resolution guidance in very nice agreement for tonight regarding the band of light rain forecast to develop along a southward moving cold front. We opted to increase POPs a bit based on this higher confidence. The aerial coverage of POPs more or less the same as the inherited forecast portrayed. Models have come in stronger with winds for Sunday. BUFKIT indicates near to low end wind advisory gusts. No headlines issued this evening, but we did increase the winds a tad and will throw a mention in the HWO. && .SHORT TERM...(This evening through Sunday) Issued at 233 PM CDT Sat Oct 28 2017 Tonight...A cold front will move through, bringing a chance of rain and breezy northwest winds. Most models depict some light rain forming along the front from northwest to southeast stretching across North Dakota. Warm air advection today has allowed temperatures to rise well above freezing. These warmer temperatures will hold on through most of the night and keep precipitation in the form of rain. During the day Sunday cold air advection will be in full force. The pressure gradient will steepen as a deep surface low passes by to the north. Northwesterly winds gusting to around 40 mph are possible during the afternoon. Most models top out with gusts at, or just below 40 mph and keep the main area of pressure rises to the southwest. Therefore, elected not to issue any wind headlines for this forecast. With colder temperatures filtering in Sunday afternoon and evening some snow may develop around the Turtle Mountains as a secondary cold front moves into the north. .LONG TERM...(Sunday night through Saturday) Issued at 233 PM CDT Sat Oct 28 2017 Overnight Sunday there is a chance of light snow as the secondary cold front and an upper level wave rotates around the low in Canada. Only minor moisture seems possible so little to know accumulation is expected. For the rest of the long term it appears rather chilly, with off and on chances for rain/snow as northwest flow keeps dropping in reinforcing shots of colder air. The best chance for precipitation over the next week appears to be Wednesday as the GFS and ECMWF models show a low moving across southern Canada again. && .AVIATION...(For the 00Z TAFS through 00Z Sunday evening) Issued at 657 PM CDT Sat Oct 28 2017 Overnight a cold front will move from north to south across North Dakota. With the FROPA, light rain and bkn-ovc mid level clouds will push from north to south. Will go with a period of -RA in the TAFs late this evening and overnight. In addition, MVFR CIGS are expected for mainly southern terminals of KDIK-KBIS-KJMS after 08Z through 14Z. Increasing northwest winds will follow the front, gusting to 35 kts at all terminals by 17Z Sunday if not before. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...NH SHORT TERM...AJ LONG TERM...AJ AVIATION...NH
Area Forecast Discussion
National Weather Service Louisville KY
1122 PM EDT Sat Oct 28 2017 .Forecast Update... Issued at 1121 PM EDT Sat Oct 28 2017 Video out of Lexington this evening shows some snow flurries flying. The latest HRRR run actually does depict scattered flurries across the region through the overnight hours. NAM soundings also show a decently deep low level saturated layer up to -8 to -9C. Given this, have added flurries in for the entire forecast area tonight. No other major changes were made. Issued at 935 PM EDT Sat Oct 28 2017 Temps very slow to fall this evening as the stratus deck remains quite solid over the Ohio Valley. We`ll remain cloudy through the night, and finally start clearing from west to east late Sunday morning as the upper trof axis finally pushes across the Ohio Valley. Min temps still on track to run just above freezing, with cloud cover and light NW winds really limiting any frost formation. No changes planned. && .Short Term...(This evening through Sunday night) Issued at 220 PM EDT Sat Oct 28 2017 As of mid-afternoon, a surface analysis had low pressure near Mackinac Island, Michigan while yesterday`s cold front was now along the spine of the Appalachians. Visible satellite imagery showed a blanket of stratus wrapping around the low from the Upper Midwest through the lower Ohio Valley. Northwest winds prevailed, and readings remained unseasonably cold in the upper 30s to lower 40s. For this evening and tonight, plan on mostly cloudy to overcast skies with the moisture remaining trapped in the low-level inversion. Moisture time-height analysis across the area shows little erosion or drying of the moisture overnight and this increased cloud cover combined with a steady wind should preclude widespread freezing or sub-freezing temperatures. No freeze headlines will be needed across southern Indiana and central Kentucky, though patchy frost may form in the sheltered areas. Lows will range from 33 to 37. For tomorrow, plan on mostly cloudy to overcast skies in the morning then some improvement west to east in the afternoon as the upper level trough axis moves east of the area. With the increased cloud cover, especially across the Bluegrass, lowered highs a few degrees. Look for readings to top out in the middle 40s. Sunday night`s lows will bottom out early in the night with calm winds and mostly clear skies expected, then begin to steady out as a light southerly wind develops along with some increasing high clouds. Readings are forecast to drop into the 30-35 range, coldest along/east of I-65. This might be near levels for a freeze or frost headline in some places but in coordination with surrounding offices, will hold off on issuing any this afternoon. .Long Term...(Monday through Saturday) Issued at 225 PM EDT Sat Oct 28 2017 Fast zonal flow will setup across the central US Monday and Tuesday with quick moving shortwaves staying north of the area. Dry conditions are expected with seasonably cool temperatures on Monday while a front swings through the area. It should pass through with just increased cloud cover in the afternoon. Plan on highs in the mid/upper 50s Monday followed by low/mid 50s on Tuesday. Lows will stay mainly in the mid 30s to around 40. Southwest flow aloft is then expected to develop Wednesday through next weekend with several disturbances moving through the flow. The first system still looks to arrive on Wednesday and Wednesday night. Confidence drops off Thursday onward as a frontal boundary may stall out in the region, and be the focus for multiple waves of rain. Overall, the end of the upcoming work week looks unsettled and will carry at least high chances to low likely range PoPs into next weekend. && .Aviation...(00Z TAF Issuance) Issued at 655 PM EDT Sat Oct 28 2017 NW flow well established in the boundary-layer, but enough low-level moisture remains trapped below an inversion at 850mb for a stratus ceiling, which has built down into MVFR but remains above fuel- alternate. Synoptic and some hi-res models try to lift this deck into VFR overnight. However, GFS LAMP still has conditional MVFR, and NARRE shows oscillating probabilities of low ceilings. Given the full suite of information vs the tendency for stratus to build down at night, will split the difference and maintain status quo well into Sunday morning, with light NW winds. Boundary-layer warming and deeper mixing should lift ceilings to VFR around midday Sunday, but won`t scatter out until mid/late afternoon as the upper trof finally pushes east of the area. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...EER/RAS Short Term...ZT Long Term...ZT Aviation...RAS
Area Forecast Discussion
National Weather Service Raleigh NC
1010 PM EDT Sat Oct 28 2017 .SYNOPSIS... A cold front will approach from the west tonight and cross central NC early Sunday. High pressure will build into our region behind the exiting front Sunday night and Monday. && .NEAR TERM /OVERNIGHT/... As of 1010 PM Saturday... Forecast will require little adjustments through the overnight. Near term model guidance as well as recent additions of the HRRR still suggest that the bulk of the shower activity associated with the front will remain west of our Piedmont counties through late evening then progress eastward after midnight, though coverage and intensity will be weaker compared to current radar presentation. Portions of the Triangle may not see appreciable rainfall until closer to daybreak Sunday. HRRR trends still depict a batch of showers and isolated t-storms lifting nwd over our southeastern counties (Sampson, Wayne and Wilson) late this evening into the overnight. This region of the state will have the best potential to experience weak destabilization at the surface as sely low level flow advect warm moist air off the Atlantic. In addition, mid level lapse rates in this area hovering between 6.5 and 7 deg C/km. Enough bulk shear is present to aid in organization of some of the cells, and with storm relative helicity projected to be between 100-200 m2/s2 after midnight, the deeper cells will likely exhibit some rotation aloft. Weak instability at the surface will likely prevent storms from becoming severe. The upper level system affecting the southern FL peninsula appears likely to disrupt the moisture transport into our region late tonight into Sunday, leading to smaller precip amounts total. This will likely be realized over the Triangle area where rainfall amounts may total a quarter of an inch or less. Min temps will likely be achieved at or shortly after daybreak as the sfc front will be crossing the Piedmont at that time. Min temps will vary from the low-mid 50s far west to the lower 60s east. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 300 PM Saturday... The front will initiate drying and cold air advection as early as sunrise in the western Piedmont, with the chances for showers tapering off post-fropa. The front will reach the I95 corridor in the early afternoon and should be east of the area by sunset. Highs will be hampered by earlier onset of cold air advection in the west, and temperatures will top out in the mid 50s...while the far east may reach 70 before the front makes it through. It will be breezy behind the front, with northwest winds gusting 20 to as much as 30 mph behind the front for a few hours. The wind will relax late tomorrow night, and a couple of hours of radiational cooling will allow mins to fall to the low and mid 30s for Monday morning. && .LONG TERM /MONDAY THROUGH SATURDAY/... As of 240 PM Saturday... The upper level low pressure system will continue moving away from the Mid-Atlantic, getting absorbed into a secondary low moving east through Canada on Monday. The remnant weak upper level trough over the Carolinas will relax on Monday. At the surface, high pressure will build over and move through the region Monday and Tuesday while a cold front lingers west of the Appalachians. The mid/upper level flow over the region will become more westerly, then southwesterly through the middle of the week as another upper level trough gradually amplifies over the central U.S. As of the latest medium- range model runs, the surface cold front should not make it into Central NC by the end of the period, likely stalling over the mtns and becoming more west-east oriented well north of the area. There is still some uncertainty regarding the eventual progression of the front late in the weekend. There is a slight chance for some rainfall over Central NC ahead of the cold front, as the cold front approaches the mtns and southeasterly return flow off the Atlantic increases. However, the parent low is so far to the northeast (over Eastern Canada) and the shear axis weakens considerably as it moves into the mtns that the chance for any significant rainfall with this system appears minimal at this time. Expect moderating temperatures; from highs in the upper 50s/low 60s and lows in the upper 30s/low 40s Monday and Monday night, to highs in the mid 70s and lows in the low/mid 50s Friday and Friday night. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 800 PM Saturday... The latest data analysis indicated a weak low pressure along the front over the SW Piedmont near KCLT. This low is forecast by the latest Hi-Res models to move northward toward KINT/KMWK in the next 3-4 hours. The cold front is slated to move into the western Piedmont, then stall for a few hours as another low develops to the south. This low pressure will then move into VA around 12-13z/Sunday propelling the cold front east across central NC during the morning. A broad area of showers with IFR CIGS/VSBYS will accompany the front as it moves slowly to the east overnight into Sunday morning. A separate area of showers with possible isolated thunderstorms is expected from near KFAY to KRDU eastward late tonight. Some thunder may need to be added to the TAF sites in these areas later, depending on development. Otherwise, VFR CIGS in the east will become IFR tonight and linger Sunday morning with IFR to MVFR CIGS with scattered to numerous showers. As the winds become more westerly and increase in speed to 15-25kt on Sunday, VFR conditions will return from southwest to northeast between 15z-21z. Finally, VFR conditions with no CIGS will arrive with much drier air late Sunday through Sunday night. Winds will remain 15-25 kt with gusts to 30 kt until 06z/Mon when the winds will begin to subside to 10 kt. VFR conditions can then be expected Sunday night through the middle of the week. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...WSS NEAR TERM...WSS SHORT TERM...mlm LONG TERM...kcp AVIATION...Badgett