Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/27/17

National Weather Service Eureka CA
225 PM PST Sun Nov 26 2017 .SYNOPSIS...A shortwave trough will pass through the region tonight. High pressure will then build and bring drier weather to the area. && .DISCUSSION...Conditions will remain wet and breezy for northwest California this afternoon and evening as the last shortwave trough passes through the region. Winds will gradually diminish tonight while showers and isolated thunderstorms taper off early tomorrow morning. Thunderstorms should be confined to the southern coastal areas, but the northern outer waters may score a few storms. High pressure will then take over the forecast and keep the majority of the CWA dry for the work week; however, a weak frontal system will skirt over northern California on Tuesday. Any rain that is received will stay north of Mendocino County with the bulk of it (a quarter inch or less) falling in Del Norte County. Following that, the next chance for rain will be over the weekend. Models agree that a trough will dig over the West Coast, but not on its placement. Temperatures are expected to be cool and conditions look to be wet during this period. && .AVIATION...A round of stronger showers moved through around Midday along the coast bringing gusty winds. Some localized wind shear was reported at KACV. This continues to move to the east this afternoon. There a few isolated showers off the coast that may move onshore onshore later this afternoon and evening. Vis satellite shows another round of heavier showers well off the coast. HRRR simulated radar shows this moving onshore around 04Z to 07Z depending on the location. There is the potential for thunder with these showers, the best chance looks to be coastal Mendocino county. For now have left them out of the TAFS. These showers are expected to start moving out of the area late tonight. Monday there may be some valley low clouds in the morning, but otherwise light to moderate northerly winds and VFR conditions are expected. MKK && .MARINE...This afternoon showers continue to move through the waters. Increased instability may result in occasional strong wind gusts this afternoon and evening, particularly near any strong showers that develop. There is also the potential for an isolated thunderstorm or two this evening. Tonight, a low pressure system will pass through the waters, causing winds to veer to the west, and then north, with occasional strong wind gusts as well...especially in the southern waters. While winds won`t be light by any means, the changing wind direction will lead to an overall subsiding of steeper, wind- driven seas. However, westerly and northwesterly swell will build in its place, maintaining an elevated and somewhat mixed sea state through Monday, even though overall wave heights will very slowly decrease. A weak weather system will weaken diminish the northerly winds and bring some light southerly winds Monday night and Tuesday. This will also bring lower seas. Seas late Monday and early Tuesday will likely be the lowest of the entire weak. Northerly winds will increase once again late Tuesday and Wednesday, and at the same time, a large northwest swell will build into the waters. As a result, seas will become large, mixed, and hazardous by mid- week. Thursday through Saturday winds will be fairly light, however seas will remain around 10 to 12 as several northwest swells move through the waters. MKK/BRC && .EKA WATCHES/WARNINGS/ADVISORIES... CA...None. NORTHWEST CALIFORNIA COASTAL WATERS...Small Craft Advisory until 9 PM PST Monday for PZZ450-455-470- 475. && $$ Visit us at Follow us on Facebook and Twitter at: For forecast zone information see the forecast zone map online:
Area Forecast Discussion
National Weather Service Marquette MI
647 PM EST Sun Nov 26 2017 .SHORT TERM...(This evening through Monday) Issued at 304 PM EST SUN NOV 26 2017 ...Breezy into early evening then again Mon aftn... Clipper shortwave/sfc low in northwest flow aloft tracked north and east of Lk Superior into this aftn. Actually ended up being warmer as skies are only now clouding up over northern Upper Michigan. Highest temps thus far have been into the upper 40s vcnty of Iron Mountain. Has also been breezy, especially on the Keweenaw with peak gusts there around 45 mph. As the clipper low moves away this evening expect winds to diminish. Skies will continue to cloud over from north to south, with most of Upper Michigan in mostly cloudy skies by the evening. Still looks like there may be a few rain and snow showers or drizzle over far east to east of Munising but should not be big issue as it is marginally cold for any lake effect. Some question in extent of cloud cover later tonight. Followed RAP 950- 900mb RH progs as they have shown low clouds upstream well through the day. Expect low clouds to stay locked in especially east half with north winds off Lk Superior and temps at top of moist layer around -8c which is good enough for lake effect clouds. Inversion building in only will trap the moisture. Clouds should partially clear over west half late tonight as sfc-H9 ridge slides overhead. Wherever breaks in the clouds occur temps may drop into to around 20F. On Monday, expect fair amount of clouds either due to lingering low clouds or mid clouds spilling across top of upper ridge sliding over Great Lakes. Clouds will be due to strong shortwave trough and sub 990mb sfc low crossing central Saskatchewan in the aftn. S to SE winds will increase ahead of the low and breezy conditions with gusts up to 30 mph should develop over forecast area. High temps will depend on how much low clouds are around and how deep we can mix, but after the warmer than expected day today and thermal ridge moving in during Mon aftn, nudged highs up toward higher end of guidance (40s to around 50F) warmest west where there should be less low cloud potential with downsloping south flow developing in the afternoon. .LONG TERM...(Monday night through Sunday) Issued at 309 PM EST SUN NOV 26 2017 The weather through the extended forecast will be pretty tranquil for late November standards. Generally zonal upper flow with embedded low amplitude disturbances will be the theme for the week. One disturbance will lead to some post frontal gusty westerly winds for the Keweenaw on Tuesday...similar to today. Cooling behind that front will be modest with 85H temps only falling back to -8C or so. Thus...lake effect processes will have a tough time getting going and don`t anticipate anything more than a few flurries for the Keweenaw Tuesday night. Surface ridging will be over the Great Lakes on Wednesday as next disturbance/front quickly approach the Upper Great Lakes late Wednesday night into Thursday. There will be a bit more moisture with this feature but all in all still pretty paltry. Only looking at a few hundreths of liquid precipitation for central and eastern areas that will fall as a mix of rain and snow. This will be the best chance for precipitation over the next seven days. There are some signs the upper pattern will begin to buckle and become more amplified by early next week, but prior to that the weather for Friday through next weekend will stay quiet with temperatures running 5-10 degrees above normal. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 646 PM EST SUN NOV 26 2017 Expect MVFR cigs to persist at KCMX and KSAW, hovering in the 015- 025 range. Ceilings may scatter out late tonight at KCMX, but expect them to hang on into most of Monday at KSAW. MVFR conditions could also develop at KIWD late this evening or overnight, but confidence is low. So, maintained a VFR forecast at this time. More strong southerly winds are possible at all TAF sites Monday afternoon but could end up being more LLWS depending on how much mixing occurs. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 304 PM EST SUN NOV 26 2017 Active Fall weather continues on Lake Superior. Winds diminish tonight but south winds increase to gales again Mon aftn into Mon night. North central and eastern sections will be favored for strongest winds. Gale warning has been issued. Winds shift to northwest gales late Tue afternoon into Tue night. This looks to be the last gale event seen this forecast period, with winds staying 15-30 kts Wed into Fri. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... Gale Warning from 3 PM Monday to 1 AM EST Tuesday for LSZ264>267. Lake Michigan... None. && $$ SHORT TERM...JLA LONG TERM...MZ AVIATION...JLB MARINE...JLA
Area Forecast Discussion
National Weather Service Portland OR
145 PM PST Sun Nov 26 2017 .SYNOPSIS...Snow levels will lower to near the Cascade passes late this afternoon and early this evening. Post-frontal showers will continue into early Monday morning. Another frontal system will produce rain and mountain snow Monday night and Tuesday with snow levels remaining near the Cascade passes. Drier conditions are expected for Wednesday before the next front arrives on Thursday. Active weather continues into next weekend. && .SHORT TERM...Tonight through Wednesday...A cold front is over the Cascades this afternoon, and should move east of the Cascades late this evening. There is a slight chance for isolated thunderstorms late this afternoon through this evening along the coast and the coastal waters as isolated lightning strikes have been observed in the offshore waters. Snow levels are lowering behind the front, and will be down to near the Cascade passes around or shortly after sunset tonight. Showers will continue tonight into Monday morning as an upper trough moves over the region. Orographic effects will result in the showers favoring the higher terrain. Rain totals should remain below 0.20 inch in most areas tonight with slightly higher amounts for the coastal mountains and the Cascades. Expect localized 2-4 inches of new snow for the south Washington Cascades tonight with 1 to 3 inches for the north Oregon Cascades. Showers will decrease overnight, but at least a slight chance for showers will continue north of Salem most of Monday. Any clearing early Monday morning will likely lead to patchy fog in the interior valleys, with the best chance south of Salem. Showers will end for a few hours Monday evening before the next front brings additional rain and mountain snow late Monday night through Tuesday night. Snow levels will start around 5000 feet with the initial precipitation early Tuesday morning, then lower down to 3500-4000 feet behind the front. This front is rather quick moving which should limit rain and snow totals. Expect 0.75 to 1 inch of rain for the coast and northern Cascades with around 0.50 inch of rain for the south and the interior valleys from late Monday night through Tuesday night. The Oregon Cascades could see half of an inch or so every 6 hours with the Washington Cascades seeing 1 to 2 inches every 6 hours. Therefore localized 4 to 8 inches 24 hour snow totals are possible for the Cascades. Showers will end early Wednesday morning and the rest of the day should remain dry. ~TJ .LONG TERM...Wednesday night through Sunday...A weak shortwave ridge aloft will keep conditions mostly dry through Wednesday night, with areas of fog redeveloping overnight over portions of the CWA. Gusty east winds near the Columbia River Gorge will likely keep fog away from the Portland Metro Wednesday night. Models then show the next frontal system moving across the forecast area on Thursday. This system will mark the beginning of another period of active weather, with another frontal system moving across the region late Friday. Conditions look to become showery on Saturday as the upper level trough dives south across the region, with snow levels falling to around 2000 ft by Saturday night. Lingering instability will keep some showers going into Sunday, but chances are low. Temperatures during the long term period will generally be a few degrees below normal, with overnight lows in the mid 30s and afternoon highs in the mid 40s. /64 && .AVIATION...Secondary narrow frontal band moved through the interior valleys 19-20Z. This feature produced IFR to MVFR vis conditions and wind gusts 25-35 kt. Generally VFR across the area at 21Z in the post frontal air mass. VFR likely to prevail through Mon morning, with areas of MVFR. Models show another weak surface trough moving across Western Washington and NW Oregon 06Z-12Z Mon, which may produce areas of MVFR. There is the potential for IFR vis to develop at KEUG and KHIO late tonight. KPDX AND APPROACHES...VFR at the terminal at 21Z and expect this to be the predominant category through Mon morning, although there will be brief periods of MVFR. Another surface trough moves over the area late tonight, which will increase the risk of MVFR cigs. Weishaar && .MARINE...Wind speeds have dropped off significantly since early this morning. Northern waters getting some gusts 15-20 kt early this afternoon, with a peak gusts of 23 kt at buoy 089. 12Z models show another surface trough moving across the north waters late tonight. GFS has stronger boundary layer wind speeds than the NAM and ECMWF, with 25-30 kt clipping the far north part of PZZ270 12Z Mon. Higher-resolution models not as robust showing generally 20 kt. Prefer the NAM and HRRR solutions. Will keep the small craft advisory for wind in the north waters, although it may be marginal late tonight and early Mon morning. Another frontal system is expected Mon night into Tue, but the brunt of the energy will stay well north of the waters. The 12Z models suggest solid small craft advisory speeds Mon night, with gales possible over the north waters. Once again, prefer the NAM for this system, with 35 kt gusts 06Z-14Z Tue. High pres builds into the waters late Tue and remains for much of the rest of the week. Seas have eased into the mid teens early this afternoon. There is a mix of8 to 10 ft longer-period swell and a secondary set of SW 11-13 ft waves. Seas fall close to 10 ft late tonight or Mon morning. Models continue to waffle on the large swell set due into the waters Tue night. Latest ENP showing a much broader area of 20-23 ft seas compared to the past couple of runs. Highest energy remains focused in the Washington waters. Unlike the past couple 20 ft plus events that were primarily wind-wave driven, the Tue night event will be large W-NW swell with long periods. Seas settle down late Wed, but remain above 10 ft through the week. Weishaar && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory for winds until 1 AM PST Monday for Coastal Waters from Cape Shoalwater WA to Cascade Head OR out 60 NM. Small Craft Advisory for hazardous seas until 4 PM PST Monday for Coastal Waters from Cape Shoalwater WA to Florence OR out 60 NM. Small Craft Advisory for Rough Columbia River Bar until 10 AM PST Monday. && $$ Interact with us via social media: This discussion is for Northwest Oregon and Southwest Washington from the Cascade crest to 60 nautical miles offshore. This area is commonly referred to as the CWA, or forecast area.
Area Forecast Discussion
National Weather Service Sacramento CA
234 PM PST Sun Nov 26 2017 .Synopsis... Rain and breezy winds continue through early Monday. Mountain travel impacts tonight into Monday as snow levels drop. Drier weather Tuesday through Friday with patchy morning fog in the valley Tuesday morning. && .Discussion... Cold front continues to make its way across the area this afternoon with rain stretching from the Sierra back to the Bay Area. A few thunderstorms become embedded in the line of rain, with strikes from the Sacramento area up into the foothills. Showers are also popping up behind the front in the northern Sac Valley with a band of heavier showers in Tehama county. HRRR hinting at Shasta County convergence band forming in typical spot NW of Redding which could also drop some locally heavy rainfall. Along with the rain, breezy winds occurring across the northern Sac Valley with gusts of 35-45 mph currently. Have covered with a short-duration wind advisory in that area. Gusts of 50-75 mph also being reported on western side of the Sierra crest. Winds should decrease throughout the night. Showers will continue across the area through the evening hours, before a secondary wave moves onshore. This will bring another burst of rain to the valley and better chances for snow across higher elevations. Models still showing some instability in the valley late this evening into the overnight hours, but confidence not super high in the occurrence of additional thunderstorms. Have left out of the forecast for now but will leave for evening shift to monitor trends. As mentioned previously, snow level forecast remains tricky as models don`t typically handle snow levels well when heavier frontal precipitation occurs. Winter storm advisory remains intact as snow levels may temporarily drop below pass levels sometime this afternoon - evening, before a bigger drop off tonight. This may also affect how much snow accumulates. Given increased traffic from the holiday weekend and strong winds, chain controls will be possible with some travel delays. Those with travel plans over the passes should keep on road conditions as things could change rapidly later today. Precipitation tapers off by around daybreak Monday with dry weather for the rest of Monday into Tuesday. Patchy valley fog may develop Tuesday morning with clear skies and lingering surface moisture. Models show a weak shortwave skirting the northern portions of the state late Tuesday, but bulk of energy and moisture remains over the Pacific NW. Have kept dry forecast for now. Northerly flow will increase on Wednesday with some breezy winds along the coastal range and western side of the Sacramento Valley. This may affect fog formation Wednesday morning somewhat, but it remains to be seen to what extent. CEO && .EXTENDED DISCUSSION (Thursday THROUGH Sunday) Stable conditions over northern California for Thursday with slightly above normal temperatures for this time of year. The next weather system will drop southward out of the Gulf of Alaska sometime late Friday into next Saturday. Model forecasts differ slightly as to the arrival of the upper level trough of low pressure with the ECMWF a bit faster than the GFS...but otherwise the amplitude of the disturbance looks similar between the two forecasts. Early projections have between 4 and 8 inches of snow for the higher elevations with some accumulations as low as 3000 feet into early next Sunday. Widespread precipitation across interior northern California between 0.25 and 0.50 inches is possible with temperatures dropping to near to slightly below normal. && .AVIATION... Frontal band moves through Norcal today and tonight. Light showers this morning with rain and high elevation snow later this morning through tonight. Mainly MVFR at TAF sites occasional IFR in heavier showers. Slight chance of thunderstorms Sacramento valley this afternoon and evening. Southerly wind gusts to 25 mph Sacramento valley. Gusts to 60 mph this afternoon and evening over the Sierra crest. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 10 AM PST Monday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. Wind Advisory until 5 PM PST this afternoon for Northeast Foothills/Sacramento Valley-Northern Sacramento Valley. && $$
Area Forecast Discussion
National Weather Service Topeka KS
500 PM CST Sun Nov 26 2017 ...AVIATION UPDATE... .SHORT TERM...(This evening through Monday) Issued at 242 PM CST Sun Nov 26 2017 The region was under northwesterly flow aloft this afternoon due to a broad mid-level ridge stretched across the western U.S. With surface high pressure continuing to shift into the southeastern U.S. and with low pressure centered over the Rockies, southwesterly surface winds prevailed. These winds combined with mostly sunny skies led to another unseasonably mild day with afternoon temperatures in the mid/upper 60s. Despite mostly clear skies tonight, the southerly wind component should keep temperatures "mild" overnight with lows in the upper 30s to low/mid 40s. A mid-level trough will move into the Pacific Northwest tonight and quickly deepen across the western U.S. on Monday. This quickly- advancing trough will help to push the surface low pressure over the Rockies further eastward into Kansas, resulting in a tightening pressure gradient developing over the CWA through the day. With model soundings showing a strong low-level temperature inversion present Monday morning, expect the gusty southwesterly winds to aid in mixing down some of these warmer conditions. Have continued to trend warmer with temperatures for tomorrow, with near or above record high temperatures possible as readings soar into the 70s. Refer to the Climate discussion below for details on the record high temperatures. Have also continued to trend higher with the wind gusts through the day, and the combination of these gusty winds with dry conditions in place will result in very high fire danger conditions across much of the outlook area. Refer to the Fire Weather discussion below for further details. .LONG TERM...(Monday night through Sunday) Issued at 242 PM CST Sun Nov 26 2017 Lee cyclogenesis occurs off the higher terrain Monday night as the upper trough deepens southeast across Colorado. Strong sfc southerly winds are noted along with a 60 to 70 kt low level jet overnight, translating to winds at 20 to 25 mph sustained. All guidance is consistent with frontal timing occurring after midnight in north central Kansas, quickly arriving in the Emporia/Topeka area by mid morning Tuesday. Convergence increases along the front as the upper forcing with the closed low skims the Oklahoma and Kansas border. Being in the northeast quadrant of the upper low is not conducive for prolonged moisture advection so have a low end chance of scattered rain showers during the afternoon and evening hours. QPF amounts are around a tenth of an inch at best. Temperatures drop down into the 30s Tuesday night behind the front, however timing with the precipitation and forecast soundings suggest precip type to remain all rain with lows in the upper 30s. In addition to the precip, drier air arrives into north central Kansas by early afternoon Tuesday, combining with the gusty winds could spell another elevated fire weather day. Details are mentioned below in the fire discussion. The remainder of the extended is fairly uneventful after Wednesday night. The GFS and Canadian models translate a progressive, upper shortwave trough through the central plains at this time. Precip occurs along and just behind the frontal boundary over far eastern KS where temperatures remain above freezing in the upper 30s so have just a mention for rain showers. The ECMWF on the other hand has been consistently further north with this system and therefore dry for our area so will maintain the slight pops this far out. Lack of a strong, cooler airmass behind these fronts deviates temps little, remaining above normal in the 50s for highs throughout the week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday) Issued at 500 PM CST Sun Nov 26 2017 Dry air remains in place, so VFR conditions are expected to continue. Models develop a low level jet across southeast KS with RAP and NAM forecast soundings developing a steep nocturnal inversion. With objective MOS guidance showing the boundary layer decoupling, think the low level jet could be close enough for some LLWS early this evening and through Monday morning. && .FIRE WEATHER... Issued at 242 PM CST Sun Nov 26 2017 For the remainder of this afternoon, some localized areas of very high fire danger will be possible, primarily across central to east central KS, where RH values were dropping into the low/mid 20 percent range with sustained winds of 15-20mph and gusts to 25mph. Breezy southwesterly winds are expected on Monday as the pressure gradient increases across the CWA due to the approaching low pressure system. These winds will quickly increase by late morning with sustained winds of 15-25mph and gusts of 30-35mph likely. Feel that models are not trending dry enough with dewpoints on Monday, so have also trended lower with these values during the afternoon hours (into the low/mid 40s). These dewpoints combined with near-record high temperatures in the 70s will result in minimum RH values dropping into the mid 20 to mid 30 percent range. As a result, very high fire danger conditions are expected across the entire outlook area Monday afternoon. On Tuesday afternoon across north central Kansas, winds shift towards the north remaining steady at 15 to 25 mph sustained, with gusts occasionally in excess of 30 mph in the afternoon. Dry air advection behind the boundary will likely drop dewpoints into the low 20s, translating to minimum RH values in the mid to upper 20 percentile. Very high fire danger conditions are expected over north central Kansas, with moderate to high fire danger elsewhere as cloud cover and slightly higher RH values counter the gusty winds. && .CLIMATE... Issued at 242 PM CST Sun Nov 26 2017 Record Highs Monday Topeka: 71 degrees set back in 1998 (Forecast: 73) Concordia: 69 degrees set back in 1933 (Forecast: 75) && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Hennecke LONG TERM...Prieto AVIATION...Wolters FIRE WEATHER...Hennecke/Prieto CLIMATE...Hennecke