Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/18/18


Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
728 PM EST Wed Jan 17 2018 .AVIATION... Uncommon warm advection pattern is now setting up over the Northern and Central Great Lakes region as Pacific moisture plume advects directly into southeastern Michigan from the northwest. Developing fast zonal gradient flow is setting the initial stage, with warm advection getting accentuated Thursday in advance of the vigorous shortwave that will dig directly down through the U.P. into Lower Michigan. High cloud now filling in over Lower Michigan is occuring on the initial warm air advection aloft. The main item in the forecast period is the overall likelihood of widespread MVFR cloud development that is forecasted to occur between 1.5 and 4.0 kft agl Thursday morning. RAP and NAM are extremely bullish on low cloud development. There remains some uncertainty yet, namely the lack of cloud development thus far upstream. However, there has been some activity on Lake Superior and model data points to Lake Michigan being a major contributor to the cloud development. Relatively higher westerly gradient flow will persist through the taf period with winds in the 15 to 25 knot range throughout the taf forecast. /DTW THRESHOLD PROBABILITIES... * Moderate for cigs aob 5kft after 14Z Thursday morning. && .PREV DISCUSSION... Issued at 348 PM EST Wed Jan 17 2018 DISCUSSION... Cloud trends will be the primary subject of the forecast for tonight with the main question being how active Lake Michigan will be in producing stratus/stratocu. Observations show the mid and high clouds overhead associated with the exit region of the upper jet over northern Ontario and a broad region of mid level isentropic ascent. These will exit eastward during the evening and allow a broad short wave ridge to force a subsidence inversion over Lower Michigan later in the night. Observations also show very dry conditions in place over the upper Midwest and northern Plains. Warmer air is moving into this region on increasing southwest flow but satellite indicates no low clouds anywhere to our west. This does not mean that Lake Michigan will not activate, only that the forecast sides with model solutions that offer more limited coverage of low clouds until observational trends support a more aggressive approach. Expect temperatures to continue an upward response to the increasing southwest wind, gusting near 30 mph during the evening, however wind chill will end up around zero for much of the night as overnight lows settle in the teens. The expectation of scattered to broken lake clouds to start Thursday will be directed farther north under gradually backing low level flow during the afternoon. Mid and high clouds associated with the compact upper level circulation will also pass mostly through the northern Great Lakes. This moisture starved feature will barely be capable of precipitation and then only on the northeast flank over northern Lake Huron where dynamic forcing will be maximized. The passage of the circulation will mark the beginning of broad upper level height rises associated with continued low level warm advection to finish the week. The pattern will be dry but steadily warmer with highs pushing 40 Friday afternoon. Significant increase in upper mass gradient is anticipated over the next few days as east Pac jet energy releases into the northern tier of the US against the southern periphery of the tropospheric polar vortex Hudson Bay/northern Quebec. Trailing energy will dig into the southwest United States Saturday through Sunday, prompting a lee cyclogenesis episode as strong right entrance support steadily matures through the weekend and becomes increasingly focused over the Great Lakes region. Light warm advection/overrunning type precip will be possible as early as Sunday morning as the low-level jet responds and moves up the developing frontal slope. Surface cyclone is then progged to lift from the Lower Missouri River Valley to The Straits by Monday into early Tuesday. Strong model support that SE Michigan will remain on the warm side of this system, supporting temps on the milder side for late January. There is potential for pre-fropa temps on Monday to make a run toward 50 before showers and possibly t-storms along the front shift through the area. Cold lake temps/ice on Lake Erie suggest usual caveats with northward progression of the surface portion of the warm front. Will leave out t-storms and remain more conservative, low to possibly mid 40s, with temps for now. Overall extended period characterized by temps on the warm side of average, high pops early next week, and mainly liquid precip. Per the norm, a brief snow-fzra-rain transition is possible as the warm front lifts through Sunday. MARINE... A Gale Warning will remain in effect through Wednesday night as strong, unstable southwest flow peaks this evening. A tight pressure gradient between Arctic high pressure over the Tennessee Valley and low pressure near James Bay will continue driving southwest gusts approaching 40 knots across Saginaw Bay and the nearshore waters with gusts reaching 40 knots over the open waters of Lake Huron through late Wednesday night. The pressure gradient will then weaken slightly early Thursday as the low pressure near James Bay departs to the east allowing winds to gradually decrease Thursday morning. Southwest flow will then continue through the remainder of the week with diminishing gust potential due to an increasingly warm, stable fetch. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...NONE. Lake Huron...Gale Warning until 4 AM EST Thursday for LHZ363-441-462. Gale Warning until 10 PM EST this evening for LHZ362-421. Lake St Clair...NONE. Michigan waters of Lake Erie...NONE. && $$ AVIATION.....CB DISCUSSION...BT/JVC MARINE.......JD You can obtain your latest National Weather Service forecasts online at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Gray ME
1018 PM EST Wed Jan 17 2018 .SYNOPSIS... Low pressure will depart the region this evening bringing the snow to an end. High pressure builds eastward into the region for the rest of the week and into the weekend with a return southwest flow bringing warmer temperatures by the weekend. A storm system may affect the region early next week with mixed precipitation and rain. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... 1000 PM Update Flurries are winding down in midcoast areas of Maine late this evening and skies are clearing over western New Hampshire. Expect clearing skies downwind of the mountains through midnight while clouds and a few flurries continue in the north. Have adjusted temp/td/sky and pop grids to reflect latest obs and expected trends. No major changes plan for the current forecast. prev disc... 700 PM Update... Quick update to drop expired headlines for Warnings and Advisories. Left over flurries currently exiting southeast New Hampshire and lingering flurries over southern Maine will be ending through midnight with no further accumulation expected. Expect clearing skies downwind of the mountains by midnight or shortly after. Have updated area pops based on current radar trends. Aside from a few temp and td tweaks no other changes planned to current forecast. prev disc... 530 PM Update...Have adjusted PoPs just a little bit for the next couple of hours based on latest trends in radar imagery. The HRRR has been doing a pretty good job with the light snowfall progressing over our forecast area early this evening. Have therefore stuck with HRRR forecast for the departure of the accum snow this evening with the departure of a short wave trough and weakening of an inverted SFC boundary. Advisories and warnings remain up until 7 PM and should be able to expire on time. Up to an additional inch is possible through that time. Previously... Low pressure will gradually move away from the region this evening bringing an end to the snow early on. Winter weather advisories are in effect for the southern half of NH until 7 pm with winter storm warnings and advisories continuing for portions of ME until that time also. A short wave trough will swing across northern New England late this afternoon and early evening allowing much the advisory and warning area to pick up an additional inch or two of snow. This will make the evening commute slippery in most areas. Some spotty freezing drizzle may occur as well for a short period of time early this evening, but that looks like a low probability at this time. Clearing is expected to occur in the wake of the short wave trough later tonight downwind of the mountains. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/... Thursday looks to be a fair weather day with seasonable temperatures. However, the northern Whites and a portion of the western ME mountains will probably see upslope snow showers especially in the morning. Another short wave trough will cross the region Thursday night with an increase in clouds. Some snow showers may occur as well if the column moistens up sufficiently. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... Zonal flow will replace the trough which has been plaguing the East Coast by the end of the week. A more southwesterly warm air advection pattern develops for the weekend and into early next week as low pressure detaches and forms along the base of southern stream troughing over the southern and central plains. Weak upslope snow showers will be possible over the White mountains and the western Maine mountains Friday through Sunday with persistent but non-significant short wave energy passing by. Precipitation then spreads east with time on Monday into Tuesday. Coastal locations may see rain with the possibility of mixed wintry p-types as an eastward moving cold front brings lifting for ascent towards low pressure pivoting up the eastern seaboard. This will allow cooler air back in with temperatures dropping back towards normal values by next Wednesday. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... Short Term /through Thursday night/...MVFR to IFR conditions early this evening in snow and low clouds will give way to VFR conditions after midnight tonight through Thursday. Long Term...Mainly VFR conditions across the region Friday through Sunday. There will be a chance of light mountains snow showers/MVFR ceilings for mainly HIE and possibly LEB during this time. Widespread lower ceilings and visibilities in possibly mixed wintry precipitation late Monday night as low pressure heads towards New England. && .MARINE... Short Term /through Thursday Night/...Marginal SCA for seas remains in effect for the ocean waters for tonight into early Thursday morning. Long Term...Waves and winds increase to near SCA conditions late Friday into Saturday in gusty SW flow before dropping off once again. && .HYDROLOGY... River flood warning for the Kennebec has been reissued as jammed up ice has caused the river to rise just above flood stage again. It is expected to go below flood stage Thursday afternoon. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...Small Craft Advisory for hazardous seas until 7 AM EST Thursday for ANZ150-152-154. && $$
Area Forecast Discussion
National Weather Service Wilmington NC
1017 PM EST Wed Jan 17 2018 .SYNOPSIS... A cold front will bring a mix of rain and snow, and will clear the coast late tonight. Cold and dry Arctic air, will spread into the region through Thursday. Temperatures will warm into the weekend as high pressure moves offshore. Another cold front will bring rain chances by Monday evening, but little cooling, and temperatures are expected to remain above normal into next week. && .NEAR TERM /THROUGH THURSDAY/... As of 900 PM Wednesday...Much of the moisture has scoured out across the ILM CWA, well ahead of the upper closed low. This potent closed low will move across the FA late this evening and overnight with continued limited moisture across the FA. Some Atlantic moisture will be drawn in, however areas north of the ILM CWA, from Cape Lookout northward, will be the beneficiary`s. Basically, will have to rely on the dynamics of the upper closed low and it`s accompanying moisture, which is not much. Due to the moisture dilemma, we have downgraded the Winter Storm Warning to a Winter Weather Advisory for those 2 counties. Have continued the Winter Wx Adv for the 4 inland counties. Due to the limited moisture, have lowered the total snow accumulations to 1 to 2 inches across the northern periphery and that`s being very generous, elsewhere, looking at 1 inch or less for the those 4 counties within the initial Winter WX Adv. Wind chills by morning will be in the upper single digits well inland. Any further decrease in temps and/or higher windgusts would produce wind chill advisory numbers which is 5 degrees or less. Previous................................................. As of 3 PM Wednesday...A Winter Storm Warning continues for Marlboro and Robeson counties, and a Winter Weather Advisory remains in effect for Darlington, Marlboro, Bladen, and Pender counties. GOES-East water vapor is showing the mid-level trough moving into the western Carolina`s. At the surface the cold frontal boundary is entering into the western portions of the forecast area. The 2 pm observations is showing rain over most of the forecast area. The latest HRRR is showing the best chances of snow in the western half of the area after 3 PM and will slowly make it to the coast. Timing for the coast appears to be after 8 PM. With the dry air it appears after the initial shot of precipiation that we will see light snow or flurries well after midnight. Also, with delay in the system making eastward have extended the warnings and advisories to 1 AM. Also, for areas south of the warning and advisory area will have to watch for black ice as any liquid precipiation that does fall will likely freeze. As the storm pushes off the coast, winds will increase and combined with the low temperatures will see wind chills in the the 8 to 13 degree range around sunrise Thursday. This is just above the Wind Chill Advisory criteria. On Thursday skies will clear but temperatures will struggle to get to 40 degrees with brisk winds. && .SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday...The mid level pattern will have evolved into a split flow regime initially and translate into a southwest flow ahead of a mid level low by Saturday morning. Although seemingly busy at the mid levels, surface high pressure will be the dominant feature. This high will move across the Gulf of Mexico then out into the Atlantic by the end of the period. Once again a temperature forecast throughout and expect lows Friday in the lower to middle 20s. Highs Friday will rebound into the 50s. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 300 PM Tuesday...The chief caption this period ? "Warming Trend". Even in wake of a cold front early next week, minimal cold air advection is seen, as the upper pattern sees a SE ATLC upper ridge gradually expand NW into the area. A weak cold pool aloft meanders eastward along the Gulf Coast this weekend and offshore by Monday, will little sensible weather impacts here. As a result, much of next week may feature sunshine and 60s in the afternoons, likely feeling like an early spring compared to the recent weather pattern. Aside from late Monday and early Tuesday, this entire period will maintain a dry column and low PWAT values. The coldest period, will be Saturday morning, near freezing, the mildest, perhaps just ahead of the cold front Monday into the upper 60s by afternoon. Tuesday looks to be the breeziest day in wake of the cold front, with W-NW breezes. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... As of 00Z...Confidence is high that cigs will improve to VFR this evening and overnight at all terminals. Until then however, confidence in TAFs is moderate. IFR cigs at KLBT will improve to MVFR 01-02Z. MVFR cigs at both KFLO/KLBT expected until VFR develops around 04Z. Expect tempo MVFR vsbys in -SN at KFLO and IFR vsbys in -SN KLBT until 04Z however. -RA/BR is moving across the coastal terminals attm with IFR at KCRE/KMYR developing NE towards KILM. KILM should drop to IFR 01-02Z. There is a chance of MVFR/-SN coastal terminals until after midnight but expect even lighter intensities than occurring now. Thursday expect SKC with NW winds 10-18kt. Extended Outlook...VFR. && .MARINE... NEAR TERM /THROUGH THURSDAY/... As of 930 PM Wednesday...Continued the SCA timeline for all waters. The NW offshore winds have begun increasing across the local waters and should breach SCA thresholds after midnight. The CFP followed by a tightening sfc pg combined with Arctic Air Advection, will result in NW winds 20-25 kt with gusts up to 30 kt possible overnight thru midday Thu. At the moment, significant seas are responding and have increased 1 to 2 ft during the past hour. The dominant 3 foot ESE ground swell at 10-12 second periods for the past few days will give way to building wind driven waves that will overtake the dominance held by the ground swell. Previous....................................................... As of 3 PM Wednesday...Currently winds are from the east with seas running 3 to 4 feet. This will change quickly as the front and a developing low shifts to the northeast off the coast. Winds are expected to reach 20 to 25 knots late this evening and seas will increase to 5 to 7 feet. The winds will weaken and with an offshore flow the seas should settle back out to 3 to 5 feet by Thursday afternoon. SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/... As of 3 PM Wednesday...Surface high pressure will move from the northern Gulf of Mexico to well offshore during the period. Between this feature and the general cyclonic flow to the north a west to southwestern flow will prevail across the waters. Wind speeds will be fairly uniform in a 10-15 knot range leaning moreso toward the higher end early then the lower end late. Significant seas will generally fall into a 2-3 foot range. LONG TERM /SATURDAY THROUGH MONDAY/... As of 3 PM Wednesday...Welcoming and friendly marine conditions this period, particularly in wake of recent weather. As high pressure slips offshore by the weekend, a milder return SW flow will prevail, with seas 3 feet or less, and even 1-2 feet at times, with winds less than 15 kt. Seas will begin to build Monday as sustained SE fetch offshore, starts pushing wave energy toward our coast. By Monday night seas of 4-5 ft in 7 second intervals, may be rolling in. No TSTMS this period, but a few rain showers can be expected Monday night, as a cold front crosses the coast. Inshore water temperatures were in the upper 40s to lower 50s. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Winter Weather Advisory until 1 AM EST Thursday for SCZ017-023- 024. NC...Winter Weather Advisory until 1 AM EST Thursday for NCZ087-096- 105. MARINE...Small Craft Advisory until 7 AM EST Thursday for AMZ254-256. Small Craft Advisory until 1 PM EST Thursday for AMZ250-252. && $$ SYNOPSIS...MJC NEAR TERM...DCH/DRH SHORT TERM...SHK LONG TERM...MJC AVIATION...MRR
Area Forecast Discussion
National Weather Service Indianapolis IN
943 PM EST Wed Jan 17 2018 .UPDATE... The Aviation Section has been updated below. && .SYNOPSIS... Issued at 230 PM EST Wed Jan 17 2018 Dry and slowly warming winter weather can be expected the for the rest of the work week across Central Indiana. High pressure in place over the southern Mississippi River Valley will continue to slowly slide southeast...keeping a warmer and drier westerly flow of air to Central Indiana. The next best chance for rain will be late this weekend and early next work week as a low pressure system approaches from the west. && .NEAR TERM /Rest of Tonight/... Issued at 730 PM EST Wed Jan 17 2018 High pressure was centered over Arkansas at 7 pm, with satellite loop showing some cirrus spilling down into northern and northeastern parts of the forecast area. Temperatures plummeted quickly over the snowpack after sunset, with mid single digits in the southwest to teens in the northeast. As a result, cut low temperatures by several degrees and adjusted hourly temperatures based on the most recent HRRR output, which was a much better match to current conditions that the hi res consensus. With southwesterly flow expect temperatures to settle in over the next hour or so and stay fairly steady then through the overnight, with the southwesterly flow bringing warm advection and combating the extra radiational cooling over the snowpack. && .SHORT TERM /Thursday through Saturday/... Issued at 230 PM EST Wed Jan 17 2018 Models continue to suggest a quiet weather pattern during this time. The GFS and NAM suggest that the broad ridge aloft over the plains and upper midwest will slowly push eastward through Saturday and very gradually flatten out. This should keep Indiana protected from any passing short waves within the flow aloft...deflecting them to the north. Through Saturday...warm air advection continues within the lower levels with 850MB temps reaching near 4c by 12Z Friday and 7C by 12Z Saturday. The surface high to the south is also expected to drift east of Florida by Saturday...which will allow warmer and more moist gulf air return to Central Indiana. Forecast soundings and Time heights remain quite dry during this period...failing to show much in the way of saturation. An exception to this is the GFS forecast soundings on Saturday which suggest some low level saturation mainly due to warm air advection. At this time...confidence in that is low given our very dry air mass. Thus will take a wait and see approach for now. Overall, will aim for partly cloudy days and mostly clear nights during this period...with temperatures at or above the forecast builder blend given the warm air advection. && .LONG TERM /Saturday Night through Wednesday/... Issued at 116 PM EST Wed Jan 17 2018 The long term portion of the forecast will be significantly warmer as the west coast ridge breaks down and shifts eastward across the country. This will allow a trailing trough axis to push into the Rockies Saturday and induce cyclogenesis in the lee of the Rockies. Warm advection and isentropic lift out ahead of this developing low will necessitate low pops for rain showers early in the weekend, with chances increasing into early next week as a well developed low pressure system pushes northeast through the Great Lakes and drags a cold front through the area. The vast majority of precipitation with this system will fall as rain, although it may turn cold enough with the wrap around precipitation behind the cold front for a few light snow showers. Blended initialization handled things well and few significant changes were required. && .AVIATION /Discussion for 180300z TAF issuance/... Issued at 943 PM EST Wed Jan 17 2018 Updated current conditions only. Previous discussion follows... VFR through the period. High pressure will continue to slide southeast with an upper ridge holding sway over central Indiana through the TAF period. The pressure gradient will increase a little Thursday resulting in slightly stronger winds (8 to 12 kts) out of around 210 to 240, with gusts of 18 to 22 kts during the afternoon. Visibilities should be unrestricted, and any clouds should be cirrus. && .IND WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...Puma NEAR TERM...CP SHORT TERM...Puma LONG TERM...Nield AVIATION...CP
Area Forecast Discussion
National Weather Service Portland OR
250 PM PST Wed Jan 17 2018 .SYNOPSIS...A cold front will move inland this evening, crossing the Cascades overnight. An upper level trough of low pres off the coast will then send a series of disturbances inland through the end of the week, keeping the region in a cooler showery pattern. Another front will move inland Sunday, bringing a round of heavier rainfall and some mountain snow. && .SHORT TERM...Tonight through Saturday...Cold front was moving onto the coast early this afternoon, ushering in a solid looking band of rain along with some gusty winds. Models indicate the front itself pushing into the Cascades this evening, with a baroclinic zone lingering into early Sat morning. The initial shortwave that pushed the front up to the coast was seen in water vapor pictures lifting ne into Vancouver Island, but another shortwave lifting up from the vicinity of 4N 132W will move across early Thu. Cross sections of moisture indicate deep enough moisture to continue with near 100 pops as the front moves through overnight, and will retain categorical pops through the night into Thu morning with the next shortwave moving through. Moist onshore flow continues through Fri and Fri night as a few more shortwaves move through. keeping pops in the likely to categorical range for showers. Model soundings continue to indicate marginal instability, centered along and off the coast Thu afternoon as the cold upper trough moves closer, so will keep a slight chance for thunderstorms over the coastal areas then. Large seas associated with the deep surface low that is running up towards the central BC coast tonight will arrive tonight and continue through Thu before decreasing again Thu night. The system bears a resemblance to a storm back on 10 Dec 2015, where seas topped out in the range of 31 to 32 ft with periods around 17 seconds, that wound up producing some property damage around Depoe Bay and Cannon Beach. GWW deep water wave heights over the coastal waters expected to top 30 ft early Thu coupled with long periods will pose a threat for coastal flooding late tonight and Thu, with the peak threat occurring through the daytime high tide early Thu afternoon. On Sat weak ridging aloft initiates weak warm air advection. will keep likely pops in for what should transition to be more stratiform precipitation. For the next few days with snow levels coming down behind the front tonight, will see snow adding up in the Cascades again. At this time however, no system appears overly strong or heavy, so accumulations through Sat should occur at rates under advisory criteria. .LONG TERM...Saturday night through Wednesday...Active weather continues through the weekend, with coast/valley rain and mountain snow. Will likely see a decent amount of snow in the Cascades on Sunday, with snow levels down around 3000 feet (below the passes). Rain for everyone else means rivers will continue to rise through Sunday. Transient ridge builds over the Pacific Northwest late Monday into Tuesday likely means a break in the rain, but energy riding over the top of the ridge means I kept a slight chance of rain and clouds in the forecast for Monday night into Tuesday. Another trough will bring more rain and another stretch of active weather starting late Tuesday through the end of next week. -McCoy && .AVIATION...Leading edge of a cold front just offshore at 21Z. Coastal areas were VFR at 21Z, but conditions expected to lower into MVFR by late afternoon. Vis may slip into high-end IFR as the cold front moves onshore. The coast will be mainly MVFR 00Z Thu through 04Z or so, followed by a mix of VFR and MVFR thereafter. Latest model guidance suggests another surface trough will impact the coast around 12Z for a higher threat of MVFR. Inland areas to remain VFR through about 02Z Thu. The cold front reaches the Willamette Valley and SW Washington interior lowlands between 02Z and 04Z, with the potential for MVFR with the front and a few hours after passage. Post-frontal pre-dominant VFR develops in the interior valleys between 07Z and 10Z, but increasing chance of MVFR between 12Z and 15Z Thu. Higher terrain becomes frequently obscured after 00Z Thu. PDX AND APPROACHES...VFR to be the dominant flight category at the terminal through at least early evening. Cold front moves across the terminal around 04Z Thu, which will result in MVFR conditions. Expect more VFR after 08Z in the post-frontal air mass. Another surface trough is expected to move across the terminal between 12Z and 15Z for an increasing threat of MVFR. Weishaar && .MARINE...General forecast trending as expected. A 960 mb to 964 mb low pres center was located near 48N 136W at 21Z. Storm force gusts to 58 kt have been noted at buoy 46005, with a 51 kt gusts at 46050 at 21Z. The forecast 80m wind field from the 19Z HRRR seems to be meshing well with buoy observations. Peak wind will occur through about 01Z Thu, with the strongest gusts over PZZ275. The coastal jet signature shown earlier by the NAM has since disappeared on recent runs with the bulk of the higher winds associated with the cold front itself. Post frontal gales to then continue for the outer waters later this evening through Thu. 12Z model runs are in better agreement regarding the Sun system. Looks like gale force wind returns to PZZ255 and PZZ275 in the 06Z-12Z Sun time frame and then move into the north zones after 12Z. Indicated gusts around 45 kt over PZZ275 Sun morning. Wind speeds settle down early next week. Seas starting to build this afternoon, near 30 ft at buoy 46005 at 21Z. Latest ENP guidance indicates seas near 40 ft at 46005 valid 00Z Thu. The highest seas are expected to move inside 60 nm by 12Z Thu. Little change in modeled wave guidance with seas 29-33 feet. The 12Z spectral guidance for buoy 46029 shows 32-33 ft peak wave heights from 12Z-18Z Thu. This is slightly higher than the Tue runs. The ECMWF continues to be 2-4 ft lower. Areas of the shoreline will be highly impacted by the expected large waves beginning late tonight. The expected 30-33 ft west swell with 15-18 second periods will contain an enormous amount of energy. Waves will generally break within a mile or so offshore, with the potential for 40 ft or greater wave heights. These waves will contain enough momentum to run water much further up the beaches. It appears this event will be more significant than the December 2014 impacts but less so than February 2006 where significant damage occurred across low lying beach and harbor areas. Seas diminish Fri, but will remain above 20 ft through Fri evening. Seas will continue to subside Fri night and Sat, easing to the lower teens by 12Z Sun. However, forecast gale force wind Sun will likely boost seas to near 20 ft. Weishaar && .PQR WATCHES/WARNINGS/ADVISORIES... OR...Coastal Flood Warning from midnight tonight to midnight PST Thursday night for Central Oregon Coast-North Oregon Coast. WA...Coastal Flood Warning from midnight tonight to midnight PST Thursday night for South Washington Coast. PZ...Storm Warning until 7 PM PST this evening for Coastal Waters from Cape Shoalwater WA to Florence OR out 60 NM. Small Craft Advisory for Rough Columbia River Bar until 4 AM PST Friday. && $$ Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland 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.