Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/05/18

Area Forecast Discussion
National Weather Service Bismarck ND
729 PM CDT Thu Oct 4 2018 .UPDATE... Issued at 728 PM CDT Thu Oct 4 2018 Based upon radar trends, put the Winter Weather Advisory into effect now instead of 1 AM CDT for Ward, McHenry, Bottineau counties. Also added McLean county to the Advisory. UPDATE Issued at 704 PM CDT Thu Oct 4 2018 Snow and fog tonight through Friday morning highlight this update. A band of moderate snow in a zone of low level moisture transport and ascent along isentropic surfaces continues across most of central and into portions of southwest North Dakota as of 2345 UTC. At precipitation onset on the leading edge of the band, the precipitation type is quickly changing to all snow with wet-bulb cooling. Some sleet may mix in with the snow far south central with partial melting with a weak warm layer aloft. The rapidly updating guidance through the 22 UTC HRRR have a good handle on this band of precipitation, and will follow their consensus for PoPs through the night and into Friday. Do expect snow to decrease across the south central into next 1-2 hours as precipitation focuses generally north of I-94 and east of North Dakota Highway 8. Snowfall amounts are relatively unchanged with this update, with no change to the Winter Weather Advisory needed at this time. A secondary band of mostly snow is expected to enter western North Dakota late tonight, and move east through central North Dakota Friday morning with a shortwave that is currently across western Montana. The HRRR/RAP/NBM/GFSLamp through their 22 UTC iterations favor fog formation through the night across southwest North Dakota with favorable southeasterly winds. A Dense Fog Advisory could be needed late tonight into Friday morning. Will also monitor the potential for light freezing drizzle southwest and south central tonight into Friday morning with possible ice loss in the column. && .SHORT TERM...(This evening through Friday) Issued at 222 PM CDT Thu Oct 4 2018 The short term will be a bit more complex because of a two pronged shortwave pattern expected to impact west and cental North Dakota over the next 24 hours. First, a warm advection pattern is currently supporting precipiation moving into south central North Dakota. WAA pattern associated with a shortwave, originally over northwest Arizona this morning, now approaching the northern plains. A mix of rain and snow is expected to start south and move north, changing to mainly all snow this evening and overnight. Three to 5 inches of snow still seems reasonable over the Devils lake Basin south through the Northern James River Valley. A second shortwave trough, over northern California, will track northeast and spread snow over northwest and far north central North Dakota, starting about 6 to 8 hours later or around midnight. For this added a second area to the winter weather advisory across the northern tier of counties, starting just after midnight midnight through 11 am CDT Friday. .LONG TERM...(Friday night through Thursday) Issued at 222 PM CDT Thu Oct 4 2018 Friday night and Saturday will see a break in the wintry weather for a short time, as the large upper level low slowly consolidates across the western CONUS. Again, lowered minimum temperatures across the region Saturday morning, with a surface high moving over some fresh snow cover should be colder than the SuperBlend guidance suggests. While the global models seem to be slowly converging to a solution, there are some differences on the scenarios. The GFS continues to be a bit more intense than the ECMWF. Both models agree on spreading snow and rain onto west and central North Dakota Sunday night and through Tuesday. After which the ECMWF becomes drier. Much uncertainty continues for the middle to later part of next week. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 728 PM CDT Thu Oct 4 2018 Multiple aviation hazards across western and central North Dakota tonight through Friday. A band of moderate snow with IFR/LIFR visibility will impact most of central North Dakota this evening and tonight. Sleet may mix with the snow south central this evening. Widespread IFR/LIFR stratus will encompass all of the west and central tonight through Friday morning. LIFR/VLIFR fog may develop southwest and south central tonight into Friday morning. Patchy freezing drizzle is also possible for these areas. A second band of snow will enter western North Dakota late tonight and move east across central North Dakota Friday morning. && .BIS WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until noon CDT Friday for NDZ004-005- 011>013-021>023-025-036-037. Winter Weather Advisory from 1 AM to noon CDT Friday for NDZ001>003-009-010. && $$ UPDATE...PA SHORT TERM...WAA LONG TERM...WAA AVIATION...PA
Area Forecast Discussion
National Weather Service San Francisco Bay Area
655 PM PDT Thu Oct 4 2018 .SYNOPSIS...Isolated showers will linger through late this afternoon before dry conditions return to the region this evening. A further drying and slight warming trend is forecast through the weekend with the potential for offshore winds at times, especially in the hills. Seasonable weather conditions are likely through the remainder of the forecast period. && of 01:53 PM PDT Thursday...Short term impacts continue to be focused around the passing upper level trough/shortwave and associated showers. Some afternoon clearing, daytime heating and passing upper level disturbance has led to a slightly unstable atmosphere with cumulus clouds on satellite. KMUX imagery continues to indicated a few scattered convective showers passing from west to east. Latest hi-res HRRR model output continues convective showers through at least 00Z this evening then diminishing as the sun sets. Current forecast reflects this thinking. Given the hit or miss shower activity rainfall amounts will vary greatly. Developed showers could produce a quick few hundredths. By tonight precip chances end with some clearing as the upper level disturbance shifts eastward. Given the recent rains, moist low levels and decreasing winds added some patchy fog to the forecast around Monterey Bay coastline and the North Bay Valleys. Warmer and drier conditions are expected on Friday with warming 850mb temps and rising 500mb heights as the trough exits to the east. Highs will still be seasonably cool even with highs in the 70s and 80s for most locations. Over the weekend model output continues to advertise an insider slider scenario with an upper level trough sweeping through NE NorCal. There could be a few showers over the Sierra, but at this point the Bay Area looks dry. More importantly, this scenario typically results in gusty north winds. Hi-res WRF model shows this to be the case as N to NE winds of 15 to 30 mph develop over the higher terrain with gusts up to 45 mph. Peak winds appear to be Saturday night into Sunday morning. If this trend keeps up on the model data a wind advisory may be need for portions of the North Bay Mts and East Bay Hills. Additionally, the north winds will enhance the warming and drying across the Bay Area for both Saturday and Sunday. From a fire stand point, the recent rains have moistened the finer fuels keeping the fire threat in check. If anything, these winds will help to dry out the fine fuels. Next week remains dry at this point as a trough remains over the Great Basin and high pressure remains off the West Coast. Did trend to warmer temperatures for much of next week. && of 7:00 PM PDT Thursday...Upper level trough moving through the area is bringing variable clouds to the area this afternoon. Bases are generally around 4000 feet but a weak front will bring brief MVFR cigs over SFO and OAK. These clouds will dissipate after 03Z. Additional low cloud development is less likely tonight as the airmass will be much drier. However patchy fog could form around STS. Vicinity of KSFO...SCT-BKN clouds around 4000 ft briefly lowering to 1500 ft which may impact visuals approaching terminal through 03Z. West winds to 15 kt diminishing after 04Z. VFR after 03Z. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...Scattered cumulus clouds clearing out after 03Z. IFR cigs return after 05Z. && of 06:51 PM PDT Thursday...Northwest winds will steadily strengthen tonight and through the upcoming weekend. Gale force winds will be possible by Saturday Afternoon into Sunday as wind speeds peak. These winds will bring steep fresh swell to the waters in the coming days. Otherwise, seas mixed with moderate to longer period northwest and southerly swells. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM SCA...Pt Arena to Pt Reyes 0-10 nm until 9 PM && $$ PUBLIC FORECAST: MM AVIATION: W Pi MARINE: DRP Visit us at Follow us on Facebook, Twitter, and YouTube at: