Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/11/17

Area Forecast Discussion
National Weather Service La Crosse WI
836 PM CST Tue Jan 10 2017 .UPDATE... Issued at 833 PM CST Tue Jan 10 2017 Based on diminishing winds and reports across the advisory area, things are improving. Still slick roads overnight but not quite as bad as early evening with enhanced blowing snow/whiteout. Will be updating services to match this expiration. Have updated the forecast to include a snow chance overnight as the current radar echoes near Omaha head toward the area. The forcing looks like 700-800mb frontogenesis and 11.01Z RAP takes this narrow region and shifts it through in the the 06-12Z time frame tonight. NW-SE oriented band should shift from SW to NE through the forecast area. Not getting too excited about it as Omaha RAOB wasnt hog wild on saturation IN the forcing area around 00Z and the air mass is dry out ahead of it. forcing is moderate and lapse rates at mid-levels are favorable. Will continue to monitor it but 30-50% chances have been added - mainly north of a KCCY-KISW line. Maybe a dusting of snow? Next weather to investigate will be Wednesdays SW-NE snow band location. UPDATE Issued at 701 PM CST Tue Jan 10 2017 Have extended the winter weather advisory based on too many impacts in the gusting winds in the 30 to 40 mph range. reports of whiteouts and accidents in southeast minnesota prompted the extension. but...with the wind gusting in the 30 mph range in wisconsin and the fresh snow...decided hazardous travel due to covered roads and isolated whiteouts /kbrf and keau reporting haze = BLSN/ would warrant the extension there too. MPX matched this area up with the extension. we think the winds will diminish over the next hours and the whiteout pockets will subside. roads will still be messy overnight with a tantalizing slushy from your favorite store turning to pretty solid ice with temperatures falling to into the 8-15F range overnight. as soon as things settle down with these hazards...will be evaluating the morning snow and ensuring the forecast is on target. && .SHORT TERM...(Tonight through Wednesday night) Issued at 230 PM CST Tue Jan 10 2017 Main concerns this period are winds this evening, snow chances with the next wave and round of lift later tonight into Wed evening, cooling temperatures. 18z data analysis had a roughly 990mb low over SW WI, lifting rather quickly NE. Liquid precip over all but the far SE/east ends of the fcst area has changed to snow. Rather impressive display of silver- dollar sized snowflakes at the ARX office when it changed over between 1015-11 AM. Deformation band of snow around the north/west side of the sfc-mid level low/trough was translating rather quickly east across the area. Vsbys in the heart of the band in the 1/4 to 3/4 mile range. Vsbys already improving to 1 to 2 miles across the west/SW ends of the fcst area. Brisk NW winds on the back side of the low spreading across the area, with colder air/falling temps already spreading across the west 1/3 of the fcst area. Model runs of 10.12z initialized well. Solutions in good agreement on the vigorous mid level shortwave/trough axis moving quickly east of the area late this afternoon/early this evening. Decent agreement continues Wed/Wed night as a northern stream wave passes across the north end of the region, while energy coming out of the west coast troughing arrives into the Upper Midwest Wed night. Short-term fcst confidence is good this cycle. For the short term, sfc low-700mb trough moves quickly NE to the east end of the MI U.P. by 00z, taking the snow with it. Any lingering -SN near/after 00z down to sct flurries as colder/drier air and post low/trough subsidence spread quickly across the area. Distance-speed tool has the west edge of the post-low cloud deck to near the MS river by 00z. Tightest pressure gradient moves across the area later this afternoon into early this evening. So far, NW winds in this tighter gradient area over SW MN into western IA have mainly been 20-30mph gusting 30-40mph. Considered a wind advisory for at least the west 1/3 to 1/2 of the fcst area thru early this evening, but with winds sub-advisory to this point, will hold off for now. Will continue with the winter weather advisory thru 00z for the winds, some drifting/blowing snow and the refreeze on untreated roads/walkways as temps fall into the teens to mid 20s. Respite from the snow rather brief across the north 1/2 to 2/3 of the fcst area. Next round of stronger lower/mid level warm advection/isentropic lift is already into the north end of the fcst area after midnight, with this forcing/lift maximized around the - 15C level. Concern later tonight is how quickly with the roughly 925- 800mb layer re-saturate and allow snow to reach the ground. Greater of the 925-800mb saturation progged over the north 1/4 to 1/3 of the fcst area by later tonight, with a deep dry 925 to nearly 700mb layer remaining over the south side of the fcst area. Consensus snow chances back in the 50-70% range across the north of the fcst area to remaining dry across the south half by 12z Wed quite reasonable. Stronger/deeper lift spreads across the north 1/3 to 1/2 of the fcst area Wed. Continued with snow chances 50-70% across the north end of the fcst area much of Wed. These blend well with neighboring grids, but may not be high enough. Potential for another 1 to 2 inches of snow along/north of hwy 29 across WI. Yet another round of increasing mid/upper level forcing/lift, ahead of the energy ejecting out of the west coast troughing, spreads across mainly the central/south parts of the fcst area late Wed night. Continued -SN chances mainly along/south of I-90 thru Wed night good for now. Blend of the guidance lows/highs for tonight thru Wed night looks well trended at this time. .LONG TERM...(Thursday through Tuesday) Issued at 230 PM CST Tue Jan 10 2017 For Thursday thru Friday night: main fcst concerns this period are lingering -SN chances Thu morning, -SN chances again Fri night. Model runs of 10.12z in good agreement as a cold trough settles over the northern great lakes Thu, then quickly giving way to more westerly flow aloft by Fri. Decent agreement for yet another W-NW flow shortwave to come across the northern plains and approach the region Fri night. Fcst confidence in the Thu thru Fri night period is generally good this cycle. Moisture/lift over the south end of the fcst area from later Wed night exits rather quickly Thu morning. Rather deep/dry airmass to then settle across the region for Thu afternoon thru Fri as hgts rise and arctic high pressure settles across the region. With the arctic high overhead and what should be clear skies and light winds, along with 925mb in the -12c to -18c range, Thu night/Friday shaping up to be a very cold period. Consensus lows mostly 0F to -15F Thu night and highs Fri mostly 5F to 15F. With a fast zonal flow and an approaching shortwave Fri night, the next round of lower level warm advection/isentropic lift, along with an increase of mid/high level moisture spreads across the area by later Fri night. The small consensus -SN chance for much of the area by later Fri night looks good at this time. With an increase of clouds and a return of south flow/warm advection, the consensus lows near normal for Fri night look good as well. For Saturday thru Tuesday (days 4 to 7): main fcst concerns this period are -SN chance Sat, precip chances Sun night into Tue, temperatures thru the period. Medium range model runs of 10.00z/10.12z in reasonable agreement for a weaker NW flow shortwave to pass across the region Sat. Detail differences on handling of waves in the flow increases for Sun, even more so for Mon into Tue. Bigger differences by Mon/Tue concern the phasing, or not, of northern/southern stream features over the mid/upper MS valley for early next week. Fcst confidence average for Sat, then below average by Mon/Tue. Northwest flow wave passing to pass on Sat looking to spread a round of weaker mid/upper level lift across the area. With sfc high pressure over the area, questions concern the amount of moisture available for snow production. Some small -SN chances on Sat okay for now. Sunday would be a between systems day with sfc high pressure ridging over the area, for what should be a dry/seasonable day. For early next week, less phased model runs offer a drier solution for Mon/Tue as the southern stream portion moves east thru the mid MS valley. More phased runs pull the southern stream energy toward/into the upper MS valley and spread precip chances northward and across much of the area as early as Sun night and continuing as late as Tue. Lower level warm advection ahead of whatever form the trough ends up taking spreads across the region for Mon/Tue. Enough so for precip type issues with any potential system for early next week. Given low confidence in the details, will stay with the model/ensemble consensus for these day 6/7 periods. Somewhat better confidence that temps for Sun-Tue will be above normal. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 700 PM CST Tue Jan 10 2017 Satellite would indicate an area of clearing is heading in before clouds try to reform and lower by morning. Confidence is not high on the details of the morning forecast into Wednesday. it appears a snow band will be around and could affect the taf sites Wednesday with ifr snow. winds are gusting in the 30-40 mph range with BLSN now. the winds will diminish as the evening continues. && .ARX WATCHES/WARNINGS/ADVISORIES... WI...Winter Weather Advisory until 9 PM CST this evening for WIZ017- 029-032>034. MN...Winter Weather Advisory until 9 PM CST this evening for MNZ079- 086>088-094>096. IA...None. && $$ UPDATE...Baumgardt SHORT TERM...RRS LONG TERM....RRS AVIATION...Baumgardt
Area Forecast Discussion
National Weather Service State College PA
1041 PM EST Tue Jan 10 2017 .SYNOPSIS... Low pressure will track northward through the Great Lakes tonight, pushing a dying cold front/occluded front through Pennsylvania overnight. An anomalous upper level ridge will build over the southeast United States later this week and this weekend. At the surface, a quasi-stationary frontal boundary will oscillate in the vicinity of Pa through the period. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... No real changes to the previous reasoning. Precip is ongoing with the far northern counties seeing a mix of sleet and freezing rain. Low level ageostrophic component to the flow is about 80kt out of the northeast, helping support the strong cold air damming scenario in place. Temperatures have been very slow to start rising and there is no reason to expect much change in that overnight. As they grudgingly top freezing, the threat for icing will diminish accordingly. Will maintain the Winter Weather Advisory, but still keep a very close eye on precip trends and the potential to upgrade to an Ice Storm Warning over the far northeast. RAP shows very strong winds just above the surface over most of Pa. The strong low level inversion is pretty much shielding us from the worst, with the possible exception of some of the highest ridgetops. A Wind Advisory remains up for the Northwest Mountains for wind gusts around or slightly in excess of 45 mph, mainly on these ridgetops. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/... Latest models have slowed the timing of the showers so there could be some lingering precipitation through the eastern and northern portion of the area. Any lingering precipitation will be rain. Daytime Wednesday will see large scale subsidence overspreading the region as the mid level shortwave passes east of the state. Much milder air will flow into the region behind occluded front, as a mid level negatively tilted ridge will allow for drier air. This will allow for some clearing skies and warming temperatures. Expect readings likely topping out between 45-50F over most of the area. Model soundings support a good deal of sunshine east of the Mtns. However, some orographic low clouds appear possible in the morning over the Alleghenies. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... Moisture transport aloft from southern CA will stream into the Ohio Valley, bringing a shot of rain Wed night into Thu night. Another wave should ride along a SW-NE oriented frontal boundary. East of the precip band, mild air will work up the Appalachians into the region, bringing a period of temperatures 15-20 degrees above normal as highs reach the 50s on Thursday and into Friday in the SE. The front pushes across the region on Friday. Colder air will gradually filter back in as 1045mb high slides across NY state. A quasi stationary boundary will setup the temperature profile on a west to east line with the northern half of the state on the edge of shallow cold air Sat- Mon. This stalled frontal boundary with moist flow should keep our PoPs higher than normal. Thus some GEFS members have ice pellets and freezing rain as a potential issue next weekend. Have adjusted the POPS and the P-type which should shift as the models come in agreement. Have kept either snow or rain currently but next weekend has a lot of uncertainty and will depend on how strong the high is and how far south the shallow arctic air slides Sat-Mon. && .AVIATION /04Z WEDNESDAY THROUGH SUNDAY/... A very strong core of SSW wind in the 2-5 KFT AGL layer will shift eastward across the state late this evening into the overnight, helping to create widespread LLWS (reaching as high as 60KT at KBFD and 35-45KT elsewhere), and a few waves of mainly freezing rain along with cigs lowering to MVFR/IFR as below freezing surface temperatures continue for much of central PA. Temperatures will slowly inch up to slightly above freezing with the precip ending primarily as rain late tonight into Wednesday morning. After that, conditions should improve to VFR areawide, with the western areas taking the longest. Another wave slides in later Wed into Wed night, bringing a return of restrictions and an area of rain - mainly to the western half of cwa. Outlook... Wed...Sub-VFR likely. Rain exits southeast airspace in the morning then returns 00-06z Thu. LLWS likely Wed ngt-Thu. Thu...Sub-VFR/LLWS likely with rain NW 1/2 airspace. Fri night-Sat...Sub-VFR likely with snow or mixed precipitation. Sunday...Areas of MVFR to IFR cigs with periods of light snow or snow showers...mainly across the southern half of the state. && .CTP WATCHES/WARNINGS/ADVISORIES... Winter Weather Advisory until 4 AM EST Wednesday FOR PAZ006- 012-018-019-037-041-042-045-046-049>053-058. Winter Weather Advisory until midnight EST tonight FOR PAZ005- 010-011-017-024>028-033>036-056-057-059-063>066. Wind Advisory until 1 AM EST Wednesday FOR PAZ004-005. && $$ Synopsis...La Corte Near Term...La Corte Short Term...Lambert/Ceru Long Term...Fitzgerald/Ceru Aviation...RXR
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
935 PM EST Tue Jan 10 2017 .UPDATE... The high wind warning will remain in effect through the evening with no changes as solid mid 40 knot wind gusts, with a few peak 50s, continue to be reported from SE Wisconsin (01Z at SBM and 02Z at FWA) through northern Indiana. There remains a few more hours of damaging wind gusts for SE Michigan in this scenario then diminishing to advisory levels shortly after midnight. The damaging wind field is being supported by strong low pressure that continues to deepen during the mid evening while exiting eastern Lake Superior. There were a few surges of mid 50 mph gusts and isolated power outages in the warm sector with showers and as temperatures rose into the mid and upper 40s throughout the region. Now, the associated cold front is on the way through SE Michigan as of this writing. Dynamic forcing with the front and strong cold advection immediately behind will steepen lapse rates below 800-850 mb where a mid 50 knot wind field continues to reside based on the latest RAP model soundings and radar VWP. Wind gusts in the 40 to 50 knot range will then remain possible at all locations through about 1 AM as the low level thermal trough surges into the region. The wind field will then quickly diminish as the low continues to move rapidly toward James Bay. The low level thermal trough will also lift north of the region and leave more neutral thermal and shallow boundary layer conditions over SE Michigan. This may allow a downgrade to advisory by then, especially in the Detroit area. && .PREV DISCUSSION... Issued at 717 PM EST Tue Jan 10 2017 AVIATION... A strong cold front will bring a westerly wind shift to the terminal corridor during early evening. Gusts will frequently be around 40 knots with a stray near 50 knots possible until about midnight. Gusts will then diminish steadily to around 20 knots by sunrise. Maintained the mention of low level wind shear due to the exceptionally high wind speed just off the surface shown in model soundings, 60-70 knots in the 1500-2000 ft layer. As the wind diminishes, the effects of colder and drier air will be seen in a clearing trend overnight. Expect just a short window of lake effect activation augmenting MVFR clouds early in the overnight before the core of coldest air shifts back northward toward sunrise. Much lighter south wind will then help maintain VFR through Wednesday afternoon. For DTW...Strong wind gusts remain the primary concern through evening due to frequent gusts running around 40 knots with increasing support from 250 degree direction. A stray gust near 50 knots remains possible through about midnight with low level wind shear 60-70 knots up to 2000 ft. Otherwise, temperatures surging into the upper 40s will maintain precipitation as all rain until the pattern shifts eastward with the cold front. //DTW Threshold Probabilities... * High for ceilings below 5k ft through evening then low late tonight into Wednesday. * Moderate for exceeding cross wind threshold from 250/G40 during evening. PREV DISCUSSION... Issued at 300 PM EST Tue Jan 10 2017 DISCUSSION... Strong cyclone, impressive in appearance on water vapor imagery, is rapidly deepening over the western Great Lakes at press time. At approximately 986mb, RAP13 progs suggest another 10mb to go in the next 9 hours or so. Accompanying wind field has ramped up considerably over the last couple of hours and will continue to rapidly strengthen over the next several hours. Radar mosaic indicates to well-defined lines of showers. The first is along the convergent right side of the 80kt low-level jet. The second is positioned immediately along a strong cold front that is anchored firmly to the left side of the LLJ. The corridor in between will contain the greatest threat for wind gusts to approach 60 mph through approximately 02z. 0-1km Richardson numbers of 0.2 to 0.35 indicating a stability balance capable of supporting eddies that will mix down bursts of higher momentum. Mean wind within this layer will increase to 50 to 55kts between now and fropa. Widespread upstream peak wind gusts of 40 to 45 kts offer certainty in meeting wind advisory criteria this evening. However, increasing availability of higher winds within the column along with some potential for deeper mixing associated with cold fropa and/or attendant convection warrant issuance of the High Wind Warning. Confidence is highest along and east of the glacial ridge where most favorable Ri values and strongest mean winds will be juxtaposed. Post-fropa environment will be characterized by a slightly weaker wind field, but far more favorable dynamic forcing. Once again, confidence is high in meeting high-end advisory level winds through at least 06z. Given existing HWW headline, simply extended it through this period. Isolated wind gust reaching warning criteria post-fropa not out of the question. Best chance north of M59. Cold advection will drive temps into the 20s tonight. Persistent jet over the great lakes will strengthen existing baroclinic zone as another shortwave ejects out of the west. Gradient will respond by turning southerly as the boundary wavers to the north. High temps easily approach 40 on Wednesday. Isentropic ascent on the warm side of the frontal zone will increase Wednesday afternoon into Wednesday night. Surface-850mb layer fgen will favor a corridor of enhanced precip rates, but attm vast majority appears to fall as rain. Departure of the wave will force the front south...any lingering precip falling as sleet/fzra across the far NW CWA late Wednesday night. Similar scenario unfolds on Thursday, but nudged further south. Higher chance for fzn precip, but QPF likely to remain on the lower side. A high pressure system pushing in from the Northern Central Plains into the Great Lakes region Thursday into Friday will keep conditions dry throughout the day on Friday, as winds remain light. For the weekend, a stationary front will set up across the Ohio Valley, which will keep the bulk of the precipitation south of Michigan, however, overrunning along the front will bring the chance light snow across the southern half of Michigan throughout Saturday morning and afternoon. The better chance for precipitation will come during the early part of next week as low pressure pushing from Texas moves northeast into the Great Lakes region. Much like yesterday, there are still large variations across the long range models regarding the timing of the low. The GFS model pushes the low over Michigan throughout Tuesday, while ECMWF model runs now push the low over us by Wednesday. Both models still exhibit decent WAA as above freezing 850 mb temperatures are ushered into the region. As this potential event is still a week out, convergence between new model runs will be needed to solidify timing and precipitation type. MARINE... The existing gusty conditions expected to steadily increase through the evening, enhanced by developing cold air advection accompanying a strong frontal passage. This will lead to an extended period of high end gales across a large portion of Lake Huron. Potential for gusts to approach storm force tonight, particularly from Saginaw Bay into central Lake Huron. Rapid reduction in wind gust magnitude then expected by the mid morning hours on Wednesday. Moderate southerly flow throughout Wednesday, but with gust potential limited by an increasingly warm and stable overlake environment. Winds turn northwesterly by Thursday as a frontal boundary sags across the region. This may provide a period of stronger winds by the end of the week as colder works back in. PREV DISCUSSION... Issued at 946 AM EST Tue Jan 10 2017 Winter Weather Advisory will be expiring on schedule this morning as ptype transition through sleet/fzra to rain is occuring on schedule. Focus for this afternoon will be on wind potential. High Wind Watch still looks good based on latest data. Surface low over Iowa is progged to deepen at a rate of about 1mb/hr for the next 12 hours, reaching 980mb just north of the straits. Wind field will be very strong, with the NAM/RAP modeling nearly 90kts at 850mb. Common ingredient often missing in potential high wind scenarios is dynamic forcing. However, ARW/RAP/EC all indicating very strong isentropic descent associated with incoming cold advection. Continue to shy away from NAM/NMM due to terrible handling of the surface layer due to snowpack and resultant erroneously high boundary layer stability. High wind warning criteria of 50kts reasonably attainable within the frontal zone itself followed by either warning or high-end advisory thereafter. In addition, convective showers leading the front will provide another mechanism by which warning criteria may be reached. Plan to hang on to the high wind watch until aftn package. && .DTX WATCHES/WARNINGS/ADVISORIES... MI...High Wind Warning until 4 AM EST Wednesday FOR MIZ047>049-053>055- 060>063-068>070-075-076-082-083. Lake Huron...Storm Warning until 7 AM EST Wednesday FOR LHZ363-421-422-441-462. Gale Warning until 7 AM EST Wednesday FOR LHZ361-362-463-464. Gale Warning until 4 AM EST Wednesday FOR LHZ442-443. Lake St Clair...Gale Warning until 1 AM EST Wednesday FOR LCZ460. Michigan waters of Lake Erie...Gale Warning until 1 AM EST Wednesday FOR LEZ444. && $$ UPDATE.......BT AVIATION.....BT DISCUSSION...JVC/AM MARINE.......MR You can obtain your latest National Weather Service forecasts online at
Area Forecast Discussion
National Weather Service Grand Rapids MI
922 PM EST Tue Jan 10 2017 LATEST UPDATE... Update .SYNOPSIS... Issued at 325 PM EST Tue Jan 10 2017 Very windy conditions will develop late this afternoon through this evening which will likely result in scattered power outages. Another low pressure system will bring a mix of rain snow and even a little sleet and light freezing rain Wednesday afternoon through Wednesday night into Thursday. Snow accumulations will be very light. Tranquil weather will return Thursday night through Friday as high pressure builds in. && .UPDATE... Issued at 921 PM EST Tue Jan 10 2017 No real changes needed to the forecast for tonight. Wind advisory is working out nicely with many locations seeing wind gusts up to around 55 mph or so with the passage and immediately behind the cold front. The cold front has moved through most of the area, having just moved through Jackson just before 02z. We will hold on to it at least for a couple of more hours with wind gusts still up enough. We may be able to cancel it before midnight if winds come down enough. Pcpn is holding on a bit behind the front, but is now in the process of diminishing. We have seen some snow mixing in with times, mainly near KGRR and areas west. The pcpn will diminish before enough cold air comes in to produce any appreciable accumulations. && .SHORT TERM...(This evening through Thursday night) Issued at 325 PM EST Tue Jan 10 2017 Primary short term fcst concerns involve determining how windy it will become late this aftn/tonight and assessment of potential for mixed pcpn Wednesday afternoon through midday Thursday. Windy conditions will develop late this afternoon through tonight as the 988 mb low near Madison WI continues to intensify and move ne. A polling of 00Z/12Z bufkit wind profiles and mixing w/height suggests wind gusts will reach 50 to 55 mph across our fcst area this evening. Latest HRRR higher res wind gust fcst guidance suggests highest gusts to around 45 kts will occur over our southern fcst area around to shortly after 00Z this evening. Based on all the aforementioned data we see this as a high end wind advisory event and will run the wind advisory from 5 pm this afternoon through 3 am Wednesday. It seems that the peak wind gusts will already occur during the early to mid evening hours. This will likely result in scattered power outages and some downed tree limbs. Thx for extensive coord on headline decisions APX/IWX/DTX. In addition given that several locations across our northern fcst area have already received 5 to near 6 inches of snow and that some mixed pcpn is still being reported across our northern counties we will leave the winter wx advisory unchanged and let it run it`s course thru 7 pm for our northern two tiers. Even as pcpn gradually transitions to liquid form hazardous travel conditions will continue for several more hours up there. The next low pressure system will cause mixed pcpn to develop Wednesday afternoon. P-type will be rain near to south of I-96 and a mix of rain and wet snow is expected across our northern fcst area. Pcpn will continue Wednesday night and the rain/snow line will slowly shift south overnight as thermal profiles slowly cool. A brief period of sleet/very light freezing rain is also possible. Pcpn will linger into Thursday before tapering off Thursday afternoon. Any snow/sleet/fzra accums would be really light with around an inch or less of snow mainly well north of I-96. Tranquil wx will return late Thursday afternoon through Thursday night as high pressure begins to build in from the northwest. .LONG TERM...(Friday through Tuesday) Issued at 325 PM EST Tue Jan 10 2017 Active weather pattern will continue into the weekend and beyond...with mid level energy rotating across Canada and the Great Lakes region and a closed low off developing off of the California coast. The northern stream energy will be the primary driver of the local weather...with a weaker impulse affecting the weather on Saturday. The system off of the California coast will move east over the weekend...and cause another precipitation event Monday and Tuesday. Precipitation type will be the main concern in the extended portions of the forecast. Cold high pressure will be in place Friday through the weekend. The weak wave that will pass through on Saturday should produce light snow...but the fast movement of the system and limited moisture should reduce the impacts of this precipitation. The event early next week may start as a wintry mix...but the majority of the precipitation looks to be liquid for this event. Friday will be the coldest day...with highs from the middle teens in north central the middle 20s in the I-94 corridor. Temperatures warm a few degrees each day...with highs on Tuesday in the upper 30s to near 40 degrees. Lows will range from the single digits in north central Michigan to the middle teens south on Saturday morning...warming to around freezing for Tuesday morning. Thanks to LOT/APX/DTX/IWX for coordination/collaboration this afternoon. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 650 PM EST Tue Jan 10 2017 Main impacts to aviation interests this evening are initially the strong winds and MVFR conditions. The front is pressing through the area, being just east of KGRR and near KAZO at 2345Z. This front will likely bring a wind shift to the WSW and the highest wind gusts to around 45-48 knots. The rain will diminish an hour or two after the front moves through with CIGS and VSBYS coming up. Can not rule out some showers changing over to a little light snow before ending by around 05z. Winds will then steadily diminish after about 02z or so. We will see the CIGS go VFR around or just after 06z tonight, and last through much of the day on Wed. Rain will move back in later in the period with MVFR-IFR conditions likely returning by the end of this fcst period. && .MARINE... Issued at 325 PM EST Tue Jan 10 2017 A gale warning is now in effect through 7 am Wednesday. Southerly winds will continue to increase to 40 to 45 gales and veer to the southwest and then west this evening. Gales will continue overnight. && .HYDROLOGY... Issued at 1147 AM EST Tue Jan 10 2017 Various ice jams on area rivers continue to be monitored. Warmer temperatures, rainfall, and snow melt will combine to elevate river levels for the remainder of the week. It is uncertain if the ice jams will release given these circumstances. Typically we need temperatures closer to 50 degrees for a few days to break them up, if the ice is thick enough. Currently the jam downstream of Robinson Township appears to be holding but the readings at Robinson have been unchanged in the last 3 days, with stable ice covering the river. Added flow behind the jam may back up river levels if the jam doesn`t break up. A Flood Watch has been issued given the uncertainty in how the river will respond over the next few days, with the possibility that a rise above flood stage may occur. Another jam on the Grand River has occurred near the Fish Ladder at Grand Rapids, which is backing up flow a bit. Currently this backwater has reached Comstock Park. No flooding is occurring at this time though rises above bankfull may occur as rain and snow melt add to the levels. Other jams are likely occurring on the Flat River near Smyrna and also the Looking Glass River near Eagle. Combined rainfall and snow melt will add to these river stages and further rises above bankfull are likely. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...Wind Advisory until 3 AM EST Wednesday for MIZ037>040-043>046- 050>052-056>059-064>067-071>074. LM...Gale Warning until 7 AM EST Wednesday for LMZ844>849. && $$ UPDATE...NJJ SYNOPSIS...Laurens SHORT TERM...Laurens LONG TERM...MWS AVIATION...NJJ HYDROLOGY...Hoving MARINE...Laurens
Area Forecast Discussion
National Weather Service Wilmington NC
1045 PM EST Tue Jan 10 2017 .SYNOPSIS... A significant warming trend will begin on Wednesday. A back door cold front will bring cooler weather for the weekend, with a gradual warming trend for the beginning of next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 1000 PM Tuesday...Coastal trough and its associated light rain will continue to slowly shift offshore overnight. A potent mid-level shortwave will lift out across the mid west and into the northeast by morning. Organized showers were weakening as they crossed the Appalachians late this eve. Will add a very small POP for a shower or two north of a BBP to LBT line toward morning. An extremely pronounced, but shallow surface inversion will develop as milder and more moist air continues to feed into the area atop cold ground. This is a very stable environment. The first 300-600 ft of the column is completely saturated. Yet, winds above the boundary layer do increase up to 20 to 30 kt through the night. However, this is more of a case of advection fog rather than radiational fog and we expect low stratus stratus and fog to fill in. Will include patchy to areas of fog across the Forecast Area overnight. Temperatures reached their lows earlier and should fluctuate through the night, increasing when the wind picks up and then falling when the wind diminishes. Overall, the column is warming overnight which will help to buoy temps. Certainly a drastic change in airmass from just 12 hours ago as the Arctic air has completely scoured out. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/... As of 230 PM Tuesday...Surface high ridging back from the western Atlantic and building weak mid level ridge will be the dominant features during the period. Low level southerly flow in conjunction with increasing mid level subsidence will result in temperatures above to well above climo through the period. Exception will be high temps along the coast where onshore flow, especially on Wed, will work to keep areas within a few miles of the coast several degrees cooler. On Thu low level winds may have more of a southwest component, keeping the Brunswick county coast and southern New Hanover county coolest. && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 230 PM Tuesday...A broad H/5 ridge will build across eastern CONUS through much of the period, with a mid-level trough moving in beginning late Monday/early Tuesday. At the surface a back- door cold front will drop south across the eastern Carolinas late on Friday with a wedge-style pattern briefly developing in its wake. A Canadian high will pass to our north late on Sunday with WAA from later Monday through Tuesday preceding the arrival of the next system beyond the Long Term. Unseasonably mild temperatures on Friday will give way to more climatologically normal temperatures Saturday, with a gradually warm-up Sunday through Monday as the airmass modifies. A more pronounced warming is on tap for Monday night through Tuesday as magnitude of WAA increases. There is the slight chance for light rain late Friday into Saturday associated with FROPA/wedge pattern set-up but in general the long term looks dry with only ample cirrus moving overhead through the period. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... As of 23z...still feeling the affects of a weak coastal trough spreading light rain mainly across KILM at times. Ceilings have been up and down at KILM, KCRE and KMYR with passing waves of precipitation and fog. HRRR has done a good job with the precipitation and continues with on and off light rain across KILM through about 04z. Will forecast mainly VFR with tempo MVFR across the coastal terminals through 12Z. Will go down to IFR across KFLO and KLBT in fog between 08z-12z. Confidence is moderate in fog and ceilings through the period. After 12z-13z conditions improve as ceilings and vsby lift to VFR all terminals. Winds light and variable becoming SW then S during the day on Wednesday under 10 kts. Extended outlook...MVFR possible with showers Wednesday morning. Otherwise expect VFR. && .MARINE... NEAR TERM /THROUGH TONIGHT/... As of 1000 PM Tuesday...A coastal trough will be shunted to the N and E overnight. South to southwest winds will develop as a coastal trough lifts to the N and E overnight. The gradient will relax slightly as the trough moves away. Wind speeds after midnight will generally be 10 kt or less, but 10 to 15 kt across the outer waters of North Carolina. Seas of 2 to 4 ft will subside to 2 to 3 ft toward morning. SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... As of 230 PM Tuesday...Surface high over the western Atlantic will maintain southerly flow through the period. Gradient will remain ill- defined with speeds generally 10 kt or less. Light winds will keep seas 2 to 3 ft through the period. LONG TERM /FRIDAY THROUGH SUNDAY/... As of 230 PM Tuesday...A cold front will drop south across the waters late on Friday, followed by a coastal trough briefly developing on Saturday. High pressure will move north of the waters late on Sunday. A relatively slack gradient through the long term means winds should not exceed the 10 to 15 kt range, with seas of around 2 or 3 ft. No headlines or advisories expected during this period. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ NEAR TERM...RJD SHORT TERM...III LONG TERM...REK AVIATION...MAC
National Weather Service Jackson KY
1030 PM EST Tue Jan 10 2017 .UPDATE... Issued at 1030 PM EST TUE JAN 10 2017 Went ahead and extended the Wind Advisory through 2 am est for the entire area based on upstream winds and convection developing. It looks like the strongest wind gusts will be pulled down by the showers as they pass. Updated the PoPs and Wx grids to reflect the latest radar trends and the most recent HRRR data. Matched up the highest PoPs with the highest wind gusts as the main threat timing the highest winds across the area through the early morning hours. Also fine tuned the T and Td grids to account for the current obs and trends. The updated grid package has been sent to the NDFD and web servers. Also, issued updated NPW, HWO, and ZFP with this issuance. UPDATE Issued at 730 PM EST TUE JAN 10 2017 00z sfc analysis shows a tight pressure gradient over the area from a deep low pressure center moving through the Great Lakes and high pressure along the East Coast. This is prompting south to southwest wind gusts of 30 to 40 mph across eastern Kentucky - mainly on the ridges - with even higher speeds possible in the most elevated terrain near the Virginia border. For all this, a Wind Advisory is in effect through 10 pm est for the entire JKL CWA. Look for the winds to settle down a bit later in the evening and continue to diminish through the rest of the night. A band of light to moderate showers will continue to press east through the area this evening before stalling and allowing the showers/stray thunderstorms associated with the actual cold front to catch up and overtake eastern Kentucky. Have continued the slight chance of thunder into the overnight hours from this. For temperatures - readings are rather mild throughout the area - running in the upper 40s to lower 50s while dewpoints are generally in the mid to upper 30s east and upper 30s to lower 40s west. Have updated the grids to reflect the latest timing on the showers and stray thunderstorms, as well, as adjusting the near term T and Td grids per the latest obs and trends. These grids have been sent to the NDFD and web servers. && .SHORT TERM...(This evening through Wednesday night) Issued at 322 PM EST TUE JAN 10 2017 The afternoon surface analysis shows a surface low continuing to deepen, as it continues to eject into the western Great Lakes. Meanwhile a cold front resides along the Central and Southern Mississippi River Valley with thunderstorms forming across Southern IL and SE MO. Ahead of the cold front is a strong LLJ at the 850 and 925mb levels in a area of tightening pressure gradient. This will keep the region gusty through the evening hours till the core of the LLJ moves NE of the region. Most the short term guidance has this happening about around 03Z and therefore will keep the NPW going at this stage of the game. The precip ahead of the cold front still looks to be related to the strong LLJ pulling moisture into the region in a more top down saturation scenario. This line of showers and perhaps a thunderstorm will progress across the region this evening through tonight, with again overall good agreement with the latest short term models. It is possible the second line developing across IL/MO catches up to the downstream line we are seeing in west and central KY. Given the chance of seeing measurable precip went definite POPs and only slight on the Thunder. The reason for that is the models are struggling to show much if any elevated instability, but the strong jet alone could lead to a few rubbles. That said, kept the slight thunder going this evening into tonight. This boundary that comes through this evening will hang up across the Tennessee Valley tonight into early Wednesday. The actual cold front slows and only makes it just SE of the Ohio River by Wednesday morning. Therefore POPs become more difficult to nail down, but this should all lift north by Wednesday Afternoon ahead of next lee side low. The question is will this lead to any thunder at all and right now leaning away from that. Just not sure we will see enough instability and SPC keeps the general thunder west of the region as well. The POPs will wane through the evening, as boundary moves north of the region. Matter of fact the SE portions of the CWA could very well dry out before wavering baroclinic zone moves slightly closer to the region. There is still some uncertainty how much if any POPs would be seen given the placement of the better lift. Therefore blended POPs will be fine in the slight to chance CAT at this point. .LONG TERM...(Thursday through Tuesday) Issued at 416 PM EST TUE JAN 10 2017 An unsettled and overall warm period will be in store from late week into next week. A split flow pattern will be in place with cyclonic flow migrating through eastern Canada and the northern United States, while an upper level low digs across California toward Baja. An upper high parked across Florida and the southeast portion of the country looks to keep the heaviest rainfall axis northwest of much of eastern Kentucky, likely lining up somewhere near the Ohio River Valley. However, positioning of this axis remains variable given several passing disturbances and lingering subsequent frontal forcing. Surface low pressure sliding northeast out of the Missouri Valley into the Great Lakes Thursday may allow for a few showers locally in the warm sector, prior to an upper low plowing through Ontario and sending a cold front into eastern Kentucky Thursday evening/night. This will bring a better chance for rain showers through Friday as the front hangs up across the region downstream of another wave migrating northeast of the Baja cutoff low. Following anomalous warmth with high temperatures in the mid 60s Thursday, a cooldown will be in store for Friday behind the front with highs topping out in the low-mid 40s for most locales with low-mid 50s south of Hal Rogers Parkway/Highway 80. A warm front will then lift through the Tennessee Valley and eastern Kentucky Friday evening and night on increasing west/southwest flow. This will lead to another widespread round of rainfall as opposed to any mix with freezing rain as a substantial warm nose develops. Still expecting surface temperatures to mostly remain above freezing as well given surface ridging sliding eastward across the Great Lakes, therefore keeping the brunt of the cold dome north of eastern Kentucky. Warm air/moisture advection should quickly bring temperatures back above freezing in the northern Bluegrass region Friday night if they do indeed drop below freezing beforehand. Rain chances will continue through the weekend into next week as passing northern stream energy combines with the previous cutoff low finally tracking northeast. Well above normal temperatures will continue, until a cold front pushes through sometime early-mid next week pending evolution/movement of the looming upper low. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) ISSUED AT 645 PM EST TUE JAN 10 2017 VFR conditions are holding on over eastern Kentucky early this evening, however an MVFR deck resides just to the west and is approaching. This will move into the Bluegrass and Lake Cumberland regions early this evening from forcing ahead of an cold front that remains further out to the west. This is all leading to a tight pressure gradient along with a strong LLJ in place across the region. Therefore, winds will be gusty through the early evening at most sites. The highest gusts will generally be at LOZ/SME/SYM with lesser ones expected to the east. Winds are expected to peak at 25 to 30 knots at least with locally higher values possible for the next several hours. These winds are expected to lessen through the rest of the evening. Then they will remain out of the south and southwest through the TAF period even as they diminish. Showers will progress deeper into the area through the rest of the evening from west to east. Will also keep a mention of thunder in the TAFs for the late evening and most of the overnight hours. MVFR conditions and continued chances of rain then last into the day Wednesday. && .JKL WATCHES/WARNINGS/ADVISORIES... Wind Advisory until 2 AM EST Wednesday for KYZ044-050>052- 058>060-068-069-079-080-083>088-104-106>120. && $$ UPDATE...GREIF SHORT TERM...DJ LONG TERM...GUSEMAN AVIATION...GREIF
Area Forecast Discussion
National Weather Service Louisville KY
852 PM EST Tue Jan 10 2017 ...Forecast Update... Issued at 854 PM EST Tue Jan 10 2017 A couple lines of thunder showers have tracked across central KY and southern IN this evening. Wind gusts ahead of these lines (gradient winds) and within the thunder showers have ranged from 35 to 45 mph, with some isolated reports of near 50 mph. Not expecting severe wind gusts with the activity across southeast Indiana. HRRR model doing a reasonable job showing these lines quickly marching east/southeast over the next 1 to 3 hours, giving way to mostly dry conditions across the area after midnight. Have updated the precip chances in the near term. Still think the wind gusts will relax under 40 mph by 10 PM EST to let the Wind Advisory expire as planned. May need to issue a SPS to cover 30 to 35 mph winds for portions of the area. Issued at 610 PM EST Tue Jan 10 2017 Still observing 35 to 40 mph wind gusts ahead of the line of showers across the area, and hi-res and near-term model guidance still points to occasional 40 mph gusts through mid-evening. Decided to extend the advisory for areas along/east of I-65 which stand the highest chances of seeing these 40 mph gusts into the mid-evening hours. Otherwise, made adjustments to the POPs in the near term and some minor adjustments to temperatures. The forecast remains on track. .Short Term (Now through Wednesday Night)... Issued at 250 PM EST Tue Jan 10 2017 A low pressure system over Wisconsin this afternoon will continue to track off to the northeast tonight. A cold front will sink through the region tonight. This front will then quickly push back to the north Wednesday as a warm front. For the remainder of the afternoon showers will be on the increase as the front approaches. Soundings do continue to indicate there will be a bit of instability develop tonight between 0-6Z, so will continue to mention a slight chance for thunderstorms. After 06Z the instability wanes as the front pushes through. Showers will end from north to south tonight as well as the front pushes south. Most areas should see a dry period early Wednesday before the front starts moving back northward. A few thunderstorms will be possible once again Wednesday. Showers will once again decrease tomorrow night as the warm front moves north of the area. Gusty winds will continue this afternoon. Sustained winds have been in the 25-30 mph range with gusts generally 40-45 mph. However, a few locations have seen gusts up to 50 mph and this may continue over the next couple of hours. The Wind Advisory expiration time still looks good as gusts should be decreasing by then. Winds should become relatively calm at the surface behind the front tonight, but winds aloft look to stay up. This should keep the atmosphere mixy enough to keep much fog from developing. Winds will once again be on the increase Wednesday night as the pressure gradient tightens up again ahead of the next front. .Long Term (Thursday through Tuesday)... Issued at 303 PM EST Tue Jan 10 2017 Thursday - Saturday... Another cold front will slowly work its way south across the lower Ohio Valley Thursday afternoon into the overnight hours. It will then stall out and become quasi-stationary near the KY-TN border through Friday and Friday night before lifting back to the north on Saturday. Winds for Thursday will once again be gusty ahead of the front passing through. Showers will develop again ahead of the front and continue off and on as it sinks southward. The concern through this time frame will be the potential for any freezing rain as the cold air behind the front tries to undercut the warm air aloft. The latest model runs suggest there could be a few hours of freezing rain on Friday morning before temperatures warm back up above freezing. There will then be another potential window for freezing rain on Saturday morning. For both of these days, the best chance for freezing rain will along and north of the I-64 corridor. South of this area, temps should remain warm enough that freezing rain will not be a concern. The good news is temperatures on Saturday should warm into the low 40s across southern IN and mid 50s across south central KY, so any impacts from the wintry precipitation should dissipate. Sunday - Tuesday... The boundary will remain in the vicinity through the end of the weekend with rounds of showers possible. It then may pull far enough north we could get a break in the rain for a period before a low pressure system ejecting out of the southwest moves through late Monday or Tuesday. Temperatures will be warming again into early next week with highs back into the 60s on Monday. && .Aviation (00Z TAF Update)... Updated at 610 PM EST Tue Jan 10 2017 Plan on gusty winds 30-35 kts through mid evening as the pressure gradient ahead of the cold front remains very tight. A line of showers will approach central Kentucky between 00-03z. There`s a slight chance of a rumble of thunder, but not enough confidence to include in the TAF right now. That front will orient itself more east/west and hang up around southern KY tonight. Moisture pooling and lighter winds will bring IFR ceilings to BWG around daybreak, meanwhile clouds could scatter out completely at SDF and possibly LEX. If so, then there`s a chance of light fog but winds just off the surface look to be strong enough to prevent any restrictions there. That stationary front will gradually lift back north tomorrow as a warm front, and with it there`s a high chance of IFR to fuel alternate ceilings with it across all of central Kentucky. Additionally, there should be some showers along the front as well. South to southwest winds will become gusty again in the afternoon, in the 20 to 25 kt range. && .LMK Watches/Warnings/Advisories... KY...Wind Advisory until 10 PM EST /9 PM CST/ this evening for KYZ028>043-045>049-053>057-063>067-073>078-081-082. IN...Wind Advisory until 10 PM EST this evening for INZ078-079-091- 092. && $$ Update.........ZT Short Term.....EER Long Term......EER Aviation.......ZT
Area Forecast Discussion
National Weather Service Medford OR
250 PM PST Tue Jan 10 2017 .DISCUSSION...The latest visible image shows a dry slot moving towards southwest Oregon. This has put an end to steady heavy precipitation and we may catch a brief break in the weather for many westside valleys early this evening. However radar returns are showing precipitation becoming convective in nature and I still could not rule out moderate to heavy showers along the Coast Range into this evening. The RAP is handling this well and actually shows precipitation decreasing in coverage area this evening and tonight and keeps it mainly confined to the south Coast Range. Meanwhile it`s still windy along the coast south of Cape Blanco, but they have been decreasing over the last few hours and the end time of the high wind warning looks good, thus we`ll allow that to expire. The models are in pretty good agreement with precipitation rates gradually decreasing tonight. The exception will be along the Cascades where a moist onshore flow will allow showers to persist there. Snow levels will be at their highest early this evening (between 5000-5500 feet), then lowering later this evening and tonight. Therefore areas along and east of the Cascades that have seen a changeover from snow to rain will probably see a changeover back to snow. Because of the above mentioned reasoning, have decided to extend the end time of the winter storm warning for the Cascades and winter storm warnings and advisories for northern Klamath County. See WSWMFR for more details. Right now were not expecting accumulating snow for the passes north of Grants Pass tonight. Could not rule out occasional snow showers, but most should be light. An upper low will move overhead on Wednesday with scattered showers and snow levels near 2500 feet. However most showers should be light, thus limiting the impact on the roads. -Petrucelli .LONG TERM...Thursday through Tuesday...The upper trough responsible for all the unsettled weather earlier this week will finally push south of the area on Thursday allowing drier air to move in from the north. This will give SW Oregon and northern California a much-needed break from the onslaught of precipitation. Any snow showers/flurries around Thursday morning across the south and east should end by midday yielding to at least partial sunshine for most of the area. However, with colder air moving in, any remaining snow/slush/moisture left on roads will re-freeze, so beware of black ice Thursday morning. Overall, expect highs Thursday to be about 10 degrees below normal with the highest anomalies east of the Cascades. The good news is that water levels on area streams, creeks and rivers should also continue to recede. With high pressure in control, Thursday night will be frigid east of the Cascades and cold over the west side. Lows will be 5 degrees below to 5 degrees above zero over the east side with 20s in the valleys west of the Cascades. Frost/freeze headlines are likely again along the coast. Some low clouds and freezing fog are also possible in the valleys, especially the west side late Thursday night and into Friday morning. Models have come into line with respect to a weak upper trough crossing the region Friday night into Saturday morning. It appears there won`t be enough moisture associated with this system to produce much more than some cloud-cover during this period, so we have continued the dry forecast and removed all mention of precipitation. Fog and low clouds will still likely be an issue for the west side valleys. Saturday night to Monday next week, models are showing short wave disturbances moving mostly to our north with a ridge axis extending from California to the Great Basin and the northern Rockies. This will bring a chance of rain to the coast and Umpqua at times, but no big storms are expected (yet). However, this will change next week and the door will open for a strong Pacific jet to extend all the way to the West Coast beginning next Tuesday. A lot can change between now and then, but this scenario may lead to our next atmospheric river event with a return of wet, windy weather, higher snow levels and a renewed threat of flooding. -Spilde && .AVIATION...0/18Z TAF CYCLE...From the Cascades west...Widespread MVFR/IFR cigs/vis with terrain obscured today with periods of moderate to heavy rain and snow. The heavier precipitation will become more showery overnight into Wednesday, but the lower conditions will persist. Snow levels up near 5000 feet through this evening will lower down to 2000 feet by Wednesday morning. East of the Cascades....Areas of MVFR cigs/vis in light to moderate snow with mountains obscured. Snow will change to rain below 5000 feet this afternoon. South winds will increase in the afternoon and KLMT could see wind gusts to near 30 knots. -Spilde && .MARINE...Updated 209 PM PST Tuesday 10 January 2017...Strong low pressure is moving into the waters this afternoon and will make landfall near Cape Blanco late this evening. South gales will continue to the south of the low with shifting but less intense winds to the north of the low. Just behind this low is what we call the bent-back occlusion, which is sometimes associated with a brief burst of strong winds. Strong winds do not always occur with bent- back occlusions, but this feature will track across the northern waters just behind the surface low, so we`ll keep a close eye on that. Even though gales are currently confined to the southern waters, mariners should not let down their guard over the northern waters this evening. Seas will remain hazardous from a combination of wind waves and swell through this evening, and then into Wednesday mostly from short period fresh swell. Seas will diminish tomorrow night, then we`ll enter of a period of relatively calmer weather with lighter north winds and subdued seas from Thursday into the weekend. -Wright && .MFR WATCHES/WARNINGS/ADVISORIES... OR...Winter Weather Advisory until 10 AM PST Wednesday for ORZ029>031. Winter Storm Warning until 10 AM PST Wednesday for ORZ029>031. Winter Storm Warning until 10 AM PST Wednesday ABOVE 3000 FEET for for ORZ025-027-028. High Wind Warning until 3 PM PST this afternoon for ORZ022. Wind Advisory until 7 PM PST this evening for ORZ026. CA...Winter Weather Advisory until 10 AM PST Wednesday for CAZ084-085. Winter Storm Warning until 10 AM PST Wednesday for CAZ084-085. Winter Storm Warning until 10 PM PST this evening ABOVE 4000 FEET for for CAZ082-083. High Wind Warning until 10 PM PST this evening for CAZ081. Wind Advisory until 10 PM PST this evening for CAZ081. Pacific Coastal Waters...Gale Warning until 8 PM PST this evening for PZZ356-376. Hazardous Seas Warning until 10 PM PST Wednesday for PZZ350-356-370-376. $$
Area Forecast Discussion
National Weather Service Charleston WV
948 PM EST Tue Jan 10 2017 .SYNOPSIS... Weak cold front washes out as it arrives tonight. A new warm front pushes north on Tuesday. A cold front crosses Thursday night, but stalls nearby this weekend. && .NEAR TERM /THROUGH WEDNESDAY/... As of 945 PM Tuesday... Issued a wind advisory for western half of the CWA. Current obs over western OH ranging from 45 to 60 mph. These should decrease some, but with a bit of convective enhancement still expect some gusts of 45-50 mph will be possible. There is some thunder with the western line now, but it has been decreasing...a trend that is expected to continue, so did not add thunder to weather. Suppose an isolated rumble may be possible across northwest CWA. As of 640 PM Tuesday... Updated forecast, mainly based on recent runs of the HRRR and RAP. Those two were the closest on current temps and rain location. This blend resulted in a bit warmer temperatures across the northern mountains tonight, there still looks like a brief window of possible freezing rain, but have reduced ice accretion to only a few hundredths of an inch. That would come from this first band of precip that is approaching the Ohio River now. The secondary area -- moving into western Ohio now -- should be all rain as it moves across the forecast area. Initially have some separation between these two area, but think the second area will catch up later tonight. As of 200 PM Tuesday... The thaw began this morning and looks to carry on for the foreseeable future. That doesn`t mean we cannot get wintry precip from time to time, and tonight is one of those times for Pocahontas County. A s/w trof and associated cold front will move through tonight with the boundary becoming frontolytic as it does so. As such rain will work back into the region this evening from west to east. There is enough lingering cold air at the surface across the Greenbrier Valley for a period of freezing rain this evening. QPF amounts to near two tenths are progged by most of the short term models. Most of this would fall as freezing rain across that location. Even if temps do climb above freezing /33 to 34/ at the height of the precipitation, ice accretion is still likely given the very cold ground. After coordinating with neighboring offices, have hoisted a freezing rain advisory for one to two tenths of ice accretion. I have also included the high elevation zone of Pocahontas County as model soundings suggest a brief period of freezing rain there as well despite being very close to the warm nose. This should be a relatively short duration event centered in the 8 to midnight time frame. Elsewhere, temperatures will be well above normal tonight. Winds will continue to pick up into early this evening as a stout low level jet remains in the vicinity. Still do not foresee criteria gusts at most locations given the WAA upglide nature, but the highest ridges in the mountains could see some gusts to 45 kts. Mid level drying quickly works in behind this system late tonight, but with abundant low level moisture in place and a slackening boundary layer flow, think low stratus will be the rule into the first half of Wednesday. After which, a developing warm front to the south will move north in the afternoon, reintroducing showers to the area. It will remain warm though, with many places soaring well into the 50s, if not touching 60 in a few locales. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/... As of 230 PM Tuesday... Models are in agreement with strong H850 southwesterly flow, 50-60 knots, Wednesday and early Thursday to bring warm air advection for temperatures to climb into the mid 60s lowlands. Wind gusts up to 30 knots can be expected over higher elevations. A warm front will lift north under southwest flow bringing rain showers likely. A cold front brings another batch of showers Thursday night into Friday morning. The front stalls south of the area keeping chances for rain showers. Horizontal flow at H500 brings a series of short waves Saturday to keep unsettled conditions. Colder air mass moves behind the cold front for temperatures slightly above normal. Freezing temperatures will return Friday night mainly across the northern half of the area. Colder low level air may result in mixed wintry precipitation, including freezing rain, in the middle Ohio valley and the northern tier of the forecast area Friday night, and perhaps down the eastern slopes of the northern WV mountains by Saturday morning, as the cold air damming wedge develops. && .LONG TERM /SATURDAY THROUGH TUESDAY/... As of 230 PM Tuesday... Front will oscillate north to south this weekend. Moisture is limited with this front providing light rain showers. The front pushes north as a warm front Sunday night and Monday, as upper level ridging builds. This may bring a break in the chance for showers. Another cold front approaches Monday night, with the chance for showers, as the upper ridge moves east of the area. An upper level short wave trough then pushes the front through on Tuesday. This should bring an end to any rain showers from west to east. The GFS is the model of choice, opting out of the colder, drier solution for late in the weekend depicted by the ECMWF, that then evolves into timing differences early next week. Temperatures are closest to GFS based guidance, fluctuating but above normal through the period. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... As of 945 PM Tuesday... A quick moving cold front moves through tonight with showers. Models pretty insistent on only isolated MVFR visibilities with these, so kept things mainly VFR visibility. Did bring in some MVFR ceilings overnight. Some question whether fog will form in the Ohio River Valley by dawn. Some models show this area clearing out with fog formation. Did include some MVFR, but low confidence on this -- could even be LIFR. Alternatively, clouds could hang tough and may lower to IFR levels. Should see mainly VFR Wednesday, but do have some showers as a warm front lifts through...which could contain MVFR. Gusty southerly winds expected into tonight -- could get some gusts of 35-45 kts, then decreasing and becoming westerly by Wednesday morning. As warm front lifts through, winds should turn back to southerly. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z THURSDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of showers may vary, and could need amendment for MVFR visibility. Low stratus and/or dense fog possible across western half of CWA overnight. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. DATE WED 01/11/17 UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14 EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09 CRW CONSISTENCY H H M H L H M L M M M M HTS CONSISTENCY M M M L M M M M M M L L BKW CONSISTENCY H H L H H M M M H H M L EKN CONSISTENCY M M L L L M M M H M H M PKB CONSISTENCY M H M H H H H H M M H L CKB CONSISTENCY M M M M M H M M M H M L AFTER 00Z THURSDAY... IFR possible in low cigs and rain late Wednesday through Wednesday night. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...Freezing Rain Advisory until 1 AM EST Wednesday for WVZ523-524. Wind Advisory until 4 AM EST Wednesday for WVZ005>010-013>017- 024>026. OH...Wind Advisory until 4 AM EST Wednesday for OHZ066-067-075-076- 083>087. KY...Wind Advisory until 4 AM EST Wednesday for KYZ101>103-105. VA...None. && $$ SYNOPSIS...ARJ/30 NEAR TERM...MZ/30 SHORT TERM...ARJ LONG TERM...ARJ AVIATION...MZ
Area Forecast Discussion
National Weather Service Blacksburg VA
919 PM EST Tue Jan 10 2017 .SYNOPSIS... Low pressure will deepen and move northeast into the Great Lakes tonight as high pressure moves off the southeast coast. A warm front will lift north across the region tonight into Wednesday. Another low will form in the Rockies on Wednesday which will track northeast through Thursday resulting in milder temperatures and occasional rain for our area through the end of the week. && .NEAR TERM /THROUGH WEDNESDAY/... As of 911 PM EST Tuesday... Sent an update to further slow down the onset of precip across the west given very dry air between the surface and 700 mb seen off evening soundings and current dewpoints in the teens to low 20s. Appears will take the second band of showers now nearing the Ohio River to moisten things up enough for rain to reach the surface per latest HRRR/RAP. However this may be as surface temps are rising enough to preclude much icing except for the deeper valleys across the north. Latest models still show the potential for some spotty/brief icing across the far north and even along the southern Blue Ridge so keeping the headline going despite lack of precip attm. Other issue is with strong southwest winds now mixing down across the western ridges as the 850 mb jet ahead of the front looks to max out at 50-60 kts through midnight. Therefore upped gusts to just below advisory levels for a few hours before the combination of the weakening jet and arrival of deeper moisture should aid in less mixing to below the inversion. Temps remain cold enough and even below freezing in some of the valleys to aid spotty icing given the cold ground and future wet bulbing. Thus lowered in spots to start before going with a non diurnal rise espcly after midnight. Previous discussion as of 657 PM EST Tuesday... Freezing rain advisory for light ice accretion and slippery road/sidewalks for eastern Greenbrier County in West Virginia and most of our northern tier of Virginia counties remains valid. However with this update I did opt to make a few changes to PoPs/Wx and hourly T`s, as well as a rather short-lived (over next 3-5 hrs) reduction in dewpoints. Lingering CAD/ridge continues to impart a cool and dry thermal and moisture profile early this evening, with temperatures hovering mainly in the mid/upper 30s with dewpoints largely in the teens. Accordingly, 2-m wet-bulb temperatures are all below freezing. These conditions precede strong pre-frontal warm advection regime with composite radar revealing a solid line of showers along a cold front now extending into eastern KY and OH. This is currently well-handled by preponderance of CAM model output; however, only the HRRR shows any appreciable eastward advance along/east of the Blue Ridge overnight. So I`ve increased PoPs for areas west of the Blue Ridge toward the Likely/Categorical range but reduced them to some extent east. Dewpoints do stand to surge from south to north particularly late evening/midnight as low- level flow veers to south/southeast and taps into higher moisture airmass now developing over the Carolinas (Td`s observed in the mid 20s- 30s). In the near-term, however, anticipate there being some wet-bulb cooling by a couple degrees before temperatures steadily rise on/after midnight. While temperatures as precipitation begins elsewhere should be mild enough for rain, it sets the stage for areas of light freezing rain along our northern counties. Timing of cessation of freezing rain around 1 am still appears reasonable. Still don`t feel amounts will be anything more than a few hundreths but that is all it can take to cause travel problems. Lows tonight should occur rather early in the 30s before steadily rising overnight. Previous near-term discussion issued at 332 PM follows... Posted a freezing rain advisory across the north this evening until 1 AM Wednesday morning. High pressure will slide east into the Atlantic ocean tonight into Wednesday. A southwest flow on the backside of the high will push warm air into our region. Used a non-diurnal temperature trend tonight. As precipitation begins...there may be a brief period when evaporative cooling as the air mass saturated lowers temperatures but the overall trend will be steady or rising tonight into Wednesday morning. Highres models like the HRRR and Hiresw-arw East showed the arrival of precipitation this evening between 23Z/6PM and 03Z/10PM. There is still enough cold air at the onset of the precipitation for freezing rain for northern portions of forecast area including the Alleghany Highlands, Greenbrier County, Rockbridge and Amherst counties. If the model temperature profiles are correct, by 1 or 2 AM temperatures across the area will be above freezing mark. Rain will spread southeast and continue for the rest of tonight into Wednesday morning. Any ice accumulations will be less than a tenth of an inch. Expect areas of fog tonight where dew points rise above freezing over the snow cover. On Wednesday, the upper level pattern will transition to a split flow regime with a closed low sinking over the Baja peninsula and weak southern stream ridging over the southeast. This will keep the Appalachians in a warm and moist southwesterly flow aloft. The warm front will continue traveling north resulting in clouds and chance of rain. Temperatures will be quite tricky as precipitation and lingering snow cover will want to lock in some cool in-situ wedging as thickness values surge. High temperatures should vary from around 40 degrees in the colder locations to the lower 50s in the southwest mountains. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... AS OF 330 PM EST Tuesday... Noticeably milder as we head through this period with southwest flow aloft and increasing heights. However, will see less sunshine and some rain at times. One batch will be moving across and out of the forecast area Wed night, as piece of energy and low level jet move across the Central Appalachians. Best chance will be north of I-64 with less in the southeast. Thursday will be mainly dry through frontal boundary will be situated from Lake Erie, southwest to the southern Plains Thursday morning and should approach the Central Appalachians by Thursday evening. Will advertise low chance pops WV to slight chance as far east as I-81. Not changing much into Friday with threat of showers increasing late Thu night into Friday with front pushing southeast to the Carolinas. Models overall showing best lift/forcing splitting with deeper moisture swing south into the TN valley and dynamics racing north toward New England. May be a case where the WV mountains to NC mountains will have the higher threat of showers while the southeast maintains low chance. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... .AS OF 320 PM EST Tuesday... Expect this period to stay milder than normal though strong high moving across New England Saturday will keep it cool/damp, with sfc front/low situated from the KY/TN area southwest to Texas. This frontal boundary will stay in the vicinity of our area into Monday then lift northward as a warm front into the Northeast by Tuesday as strong upper low pushes east and north into the Plains. The southwest flow aloft will keep the moisture streaming in and will see temps about 10-20 degrees above normal early next week. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... As of 657 PM EST Tuesday... VFR conditions through the next 3 hrs with developing low- level wind shear as southwesterly winds increase to near 45 kts. Flight categories then start to deteriorate, with a gradual VFR/MVFR as frontal boundary lowers ceilings and brings light rain especially western TAFs. Potential for slick runways at LWB due to initial freezing rain. As dewpoints begin to climb to values above freezing over at least a light cold snowpack, potential for MVFR fog to develop over the snow is possible and feel the best chance at this would be at DAN. South winds 6-11 kts should predominate with gusts to 25 kts at BLF through overnight. Precipitation into early Wednesday may prove spotty at best. However as southern end of frontal boundary sags southward but still hangs around by late in the day Wednesday ceilings will begin to lower to an eventual IFR/LIFR. South winds on Wednesday 4-8 kts eventually become light and variable by late Wednesday afternoon. Extended Aviation Discussion... Moisture returns back north Wednesday night ahead of a stronger frontal system and associated low pressure to the west. This likely to maintain areas of sub-VFR within lower cigs and patchy rain showers Wednesday evening into Wednesday night before seeing improvement back to VFR on Thursday ahead of the next front. This second frontal system will work its way into the region Friday into Saturday, maintaining the threat for additional sub- VFR in low cigs along with light rain and/or drizzle. Unsettled weather will continue into early next week. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Freezing Rain Advisory until 1 AM EST Wednesday for VAZ019-020- 024-035. NC...None. WV...Freezing Rain Advisory until 1 AM EST Wednesday for WVZ507. && $$ SYNOPSIS...AMS/KK NEAR TERM...AL/JH/KK SHORT TERM...MBS LONG TERM...WP AVIATION...AL/AMS/KK