Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/14/18

Area Forecast Discussion
National Weather Service Wakefield VA
948 PM EDT Tue Mar 13 2018 .SYNOPSIS... Strong low pressure will remain well off the New England coast tonight and Wednesday as high pressure builds from the Plains states across the deep south through Thursday. && .NEAR TERM /THROUGH WEDNESDAY/... The latest wv imagery indicates a powerful storm system well off the coast of srn New England, with 2 centers of upper level low pressure, one over the Great Lakes and the other offshore near the sfc low. These two upper level lows are progged to phase into a single low tonight into Wed. Light WNW flow this evening with temperatures in the mid 30s to low 40s under a partly cloudy to mostly clear sky. The next upper level shortwave (currently dropping SE across IL/IN), rapidly moves farther SE to the lower OH Valley between 03-06Z, and then into the Carolinas by ~12Z/Wed morning. Expect clouds to increase over the local area after midnight, with skies becoming mostly cloudy prior to daybreak on Wed. GFS continues to be most aggressive regarding potential for a quick burst of accumulating snow over far southern VA and NE NC, while the NAM/ECMWF support the clouds and probably some flurries or brief snow showers but little to no accumulation. Genly siding with the drier scenario of the NAM/ECMWF at this time (which is supported by HRRR trends), given what will initially be a dry low level airmass and only a few hrs worth of favorable lift through the dGZ. However, did bumps PoPs up to 30-40% for snow showers and a light dusting will be possible. Otherwise, partial clearing/drier air filters back in rather quickly from 12-15Z/Wed. Remaining quite chilly for mid-March with highs only ranging through the 40s (about 15 degrees below avg). && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Clearing out behind the departing shortwave Wed night with lows in the mid 20s to lower 30s. Mostly sunny to partly cloudy on Thursday, and turning a little warmer as surface high pressure builds across the eastern Gulf coast into the Carolinas, allowing for a WSW low level flow and deep mixing. Highs will be close to 60 F across south central VA and interior NE NC, with lower 50s on the eastern shore. Mostly clear Thu night with lows mainly in the 30s. Upper trough centered over eastern Canada amplifies a bit on Fri with sfc high pressure building ESE from the Great Lakes into the mid-Atlc. Partly-mostly sunny but turning cooler with highs in the 40s north to the mid 50s south. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Overall pattern will continue to be rather progressive during the extended period, with a couple of low pressure areas moving into and acrs the Mid Atlc region bringing chances for pcpn. The first low will be a weaker system Sat aftn thru Sun, with slght chc to sml chc PoPs acrs mainly the srn half of the region. The second low looks like a stronger/possibly more significant system for Mon night into Tue night. At this time, temps look to be warm enough for just rain everywhere thru most of the event, but could end as some snow, as the system intensifies off the Mid Atlc coast. Highs will range fm the upper 40s to lower 50s Sat, ranging thru the 50s Sun, ranging thru the 50s to lower 60s Mon, and ranging fm the lower 40s extrm NNW, to the mid to upper 50s extrm SE VA and NE NC. Lows will range fm the mid 20s to lower 30s Fri night, in the mid 30s to near 40 Sat night, in the mid 30s to lower 40s Sun night, and ranging fm the mid 30s to mid 40s Mon night. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Low pressure remains off the New England coast as of 00z with high pressure centered well W of the region over the Plains states. VFR conditions prevail through this evening at all terminals with a WNW wind diminishing to 5-10kt. A fast moving/weak system is expected to push across NC overnight and move off the coast early Wed. Potential for some flurries or possibly even a brief snow shower at KECG/KORF. MVFR flight restrictions most likely at KECG, from about 09-13Z or so. Otherwise, another round of a gusty WNW wind is expected Wednesday with wind speeds of 10-15kt and gusts to 20-25kt. A period of bkn cigs ~8kft are expected Wednesday aftn. VFR/partly cloudy and breezy/windy with a gusty W wind once again during the day Thursday. Dry and breezy/windy Friday with the wind shifting to NW behind a cold front. High pressure briefly builds into the are Friday night with a quick moving system bringing a minimal chc of showers Saturday. High pressure builds N of the region Sunday. && .MARINE... Conditions are slowly improving across the area waters as the strong powerful storm system is now moved into New England and the Canadian Maritimes. The northwest flow is expected to continue for the next 3 days but there will be some ebb and flow with the winds during that period. A couple weak low pressure systems rotating around the main area of low pressure to the north will impact the region on Wednesday and again on Thursday. In advance of each of these waves, expect the winds to relax some and drop below SCA levels. But in the coastal waters, the seas will remain above 5 FT for most of the time into Friday so SCA flags will likely be needed into Friday. So for tonight, will see a waning of the winds in advance this first area of low pressure. So will allow the SCA flags on the Bay, area rivers and Currituck sound come down either with this advisory or later this evening. But they will remain up with the seas on the Coastal waters. Once this wave of low pressure passes the area Wednesday morning, will see the NW flow increase again to 15 to 25 kt making SCA flags necessary for a short period of time Wed afternoon into Wed night. Conditions will again relax again before another wave slides across late on Thursday, again allowing the NW flow to briefly increase back to SCA levels into Friday morning, before high pressure finally builds into the area and allow for more tranquil conditions For Friday and Saturday. A weak wave of low pressure may impact the region on Sunday, but with westerly flow and little cold air around, should be little impact on the waters. && .AKQ WATCHES/WARNINGS/ADVISORIES... MD...None. NC...None. VA...None. MARINE...Small Craft Advisory until 10 PM EDT this evening for ANZ634. Small Craft Advisory until 4 PM EDT Wednesday for ANZ650-652- 654-656-658. && $$ SYNOPSIS...LKB NEAR TERM...LKB/AJZ SHORT TERM...LKB/MAM LONG TERM...TMG AVIATION...AJZ/LKB MARINE...ESS
Area Forecast Discussion...Updated
National Weather Service Billings MT
835 PM MDT Tue Mar 13 2018 .UPDATE... Upper ridge and dry airmass continued over the forecast area this evening per water vapor imagery. Chances for overnight and early morning fog will be confined to the Yellowstone River Valley around KMLS where humidities will be high. The HRRR hinted at possible fog in this area as well. Warm advection will bring 850 mb temperatures to +8 degrees C by 12Z Wednesday. These temperatures will be higher than they were back at 12Z this morning, and surface temperatures were running higher than this time last night. Dewpoints were in the 20s this evening. The above factors supported higher min temperatures than what occurred last night, and guidance was in good agreement with the min temperatures. Mostly clear skies will continue through the night with just some high clouds over the SW part of the area. Only forecast adjustment was to bring winds more in line with ADJLAV guidance which had captured the observed easterly component well this evening. Arthur && .SHORT TERM...valid for Wed and Thu... The rest of the today will be quiet. There could be some more localized fog in the east again, mainly in the river valleys. Given that the snowpack is providing some boundary layer moisture and then letting temperatures cool off at night cannot rule it out. Tomorrow an initial wave energy moving through during the afternoon bringing some snow showers to the mountains, and some rain to the lower elevations. There will be a bit of a break during the day Thursday before more energy works into the area, with a deformation zone beginning to setup from Miles City west. There is some decent QPF overnight with some areas over a quarter of an inch. The cold air is in by the time the precip starts, so this will likely fall as snow, but given the much warmer temperatures to start with, it is going to be a fairly wet snow. This will still result in 1 to 2 inches of new snowfall by Friday morning. Reimer .LONG TERM...valid for Fri...Sat...Sun...Mon...Tue... Models have come into alignment on wet snow event Thursday night through Friday. An upper trough over the western United States kicks energy out into the midwest Thursday night. This sets up a prolonged period of diffluence over the forecast area. Cold air will get pulled down as a surface low deepens over Wyoming, with 850mb temperatures falling to -3c. A deep period of upslope will develop. Have raised PoPs and snow amounts for Friday. A significant accumulation of snow is possible with this storm (mainly over south central Montana and Sheridan county Wyoming) and will have to keep a close eye on this for potential highlights. The main low moves out of the western United States and slides into the northern Rockies Saturday night and Sunday. This could generate another wet snow event. The impacts on this event could be farther east than the previous one, hitting southeast Montana harder than south central. Models were still struggling with timing and placement of the low kicking out, so will keep PoPs scattered for now. Confidence was growing on temperatures remaining below normal this weekend, into early next week. TWH && .AVIATION... Dry, high pressure aloft will dominate the weather with clear skies and light winds. Areas of river valley fog are possible from KBIL east, and will continue until around 18z Wednesday. Arthur && .PRELIMINARY POINT TEMP/POPS... Wed Thu Fri Sat Sun Mon Tue ----------------------------------------------------------- BIL 026/049 029/048 029/039 026/044 025/040 024/041 023/044 00/U 76/R 88/O 31/B 35/O 54/O 11/U LVM 031/057 034/050 030/043 028/047 027/042 027/043 025/046 03/W 76/R 56/O 21/B 45/O 43/O 11/U HDN 020/048 024/048 024/039 023/045 022/040 020/041 017/045 00/U 53/R 88/O 41/B 34/O 54/O 11/U MLS 017/040 025/039 023/035 021/037 020/036 019/034 016/037 00/U 23/J 75/S 31/B 25/S 64/S 21/B 4BQ 023/047 027/049 025/038 024/044 024/037 021/038 018/042 00/U 33/W 88/O 31/B 26/S 75/S 11/B BHK 020/042 021/037 022/033 022/038 021/036 018/033 015/037 00/U 22/J 42/S 11/B 25/S 72/S 11/B SHR 023/053 032/052 029/041 026/046 025/039 023/041 020/044 00/U 42/R 88/O 31/B 34/O 54/O 11/U && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...None. WY...None. && $$
Area Forecast Discussion
National Weather Service Caribou ME
1128 PM EDT Tue Mar 13 2018 .SYNOPSIS... Intense low pressure will move northeast and cross Nova Scotia overnight then slowly north through the northern Canadian Maritimes Wednesday night through Friday. A cold front from northern Canada will cross the region Friday night. && .NEAR TERM /THROUGH WEDNESDAY/... 1110 PM Update... Adjusted the hrly temps w/a bump up across eastern Washington County as Maritime air gets wrapped into the region. Reports from Lubec w/light rain mixing in w/the snow at 34F. The latest run of the RAP & HRRR doing ok the warmer temps moving into eastern Washington County. It looks like temps will stay up from earlier predictions and decided to raise them a few degrees overnight. Used the blend of the RAP and HRRR for progression of heavier snow nnw overnight. It looks like NE Aroostook County will see just on and off show. Fort Kent and Frenchville receiving light snow. Spotter in Fort Kent reported the snow to be very light. Steady snow w/pockets of heavy snow occurring from north-central areas down to the coast as radar depicted. Mid level low to lift up into the state overnight w/banding potential shifting further n and w. Kept headlines as they are w/the Blizzard Warning staying up for the coast as winds still gusting to around 40 mph according to spotter reports. Winter Storm Warnings remain up elsewhere. Previous Discussion... Snow becoming heavy at times tonight across central and Northern areas. Across far northeast Aroostook County, snow will be slower to begin, do to some drier air remaining in place, thus snow amounts will be just a bit lower here. A Blizzard Warning remains in effect for the Downeast coast overnight, where travel will be very difficult to impossible due to the combination of heavy snow and gusty northeast winds. Across interior Downeast, including the greater Bangor region, Winter Storm Warnings remain up into through Wednesday. A Winter Storm Warning remains up for the Central highlands and Southeast Aroostook through midnight Wednesday. A Winter Storm Warning remains for far Northern Aroostook through 6 am Thursday. The low will continue to track north through the Canadian Maritimes on Wednesday, with snow continuing through much of the day. The snow will begin to wind down,especially across Downeast areas later Wednesday. && .SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/... Whats left of deformation lgt snfl will cont across the N hlf of the Rgn Wed ngt with Cntrl and Downeast areas tapering to sct sn shwrs as the upper low conts to move slowly N from Nrn NB prov into the Nrn Maritimes. Wntr stm wrngs have been xtnded a few hrs longer into or thru Wed ngt due to contg steady accumulating snfl into this pd. Sn shwrs will then cont thru the day Thu, with warmer Sfc-BL temps resulting in rn mixing with sn shwrs durg the aftn across Cntrl and Downeast areas. Unsettled conditions will cont Thu ngt into Fri as the upper low remains ovr the Nrn Can Maritimes, with most sn shwrs over Nrn areas durg these pds. Temps will cont mild, spcly ovrngt lows. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... A clipper s/wv alf and associated sfc cold front from Nrn Can will bring the region the first shot of drier low residence arctic air in nearly 3 weeks as it crosses the Rgn Fri ngt with isold to sct sn shwrs, colder ovrngt lows and and day tm hi temps Sat, and with the potential of more day tm sunshine. Another stronger clipper s/wv from Nrn Can potentially will bring the region a better chc of sn shwrs late Sat ngt into Sun followed by dry...colder mdt residence arctic air from Nrn Can into the Rgn Sun ngt contg into Tue with perhaps some modification of the air mass by Tue from milder air advcg SW from the Nrn Can Maritimes. && .AVIATION /03Z WEDNESDAY THROUGH SUNDAY/... NEAR TERM: Widespread LIFR/VLIFR conditions will persist at KBGR/KBHB this evening in heavy snow/blowing snow, with Northeast wind gusts to 40 kt possible, especially KBHB where Blizzard conditions are expected. Further north, snow is expected to overspread the rest of the terminals this evening with IFR/LIFR conditions developing at the remaining terminals. IFR conditions are expected to persist on Wednesday in continued snow. SHORT TO LONG TERM: IFR conditions across all TAF sites Wed ngt in lgt snfl will gradually improve to MVFR from S to N durg the day Thu in sn shwrs, with Downeast sites improving to VFR Thu ngt. Conditions improve to VFR across Nrn TAF sites Fri ngt from MVFR clgs/vsbys with remnant sn shwrs. VFR conditions then xpctd all TAF sites Sat into Sat eve before another possible pd of MVFR clgs/vsbys with sn shwrs occurs for msly Nrn TAF sites late Sat ngt and Sun. && .MARINE... NEAR TERM: Gale Force conditions continue into early Wednesday across all the waters. Visibility will be reduced to less than 1 NM at times tonight into Wednesday in snow. SHORT TO LONG TERM: Strong SCA conditions Wed ngt will gradually subside to low end SCA or below SCA thresholds aftwrds. Kept close to WW3/NWPS wv guidance for fcst wv hts thru these ptns of the fcst. && .CAR WATCHES/WARNINGS/ADVISORIES... ME...Winter Storm Warning until 6 AM EDT Thursday for MEZ001-002. Winter Storm Warning until midnight EDT Wednesday night for MEZ003>006-010. Winter Storm Warning until 6 PM EDT Wednesday for MEZ011- 015>017-031-032. Blizzard Warning until 8 AM EDT Wednesday for MEZ029-030. MARINE...Gale Warning until 6 PM EDT Wednesday for ANZ050>052. && $$ Near Term...Hewitt
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
927 PM CDT Tue Mar 13 2018 .UPDATE... Updated for evening discussion. && .DISCUSSION... Clear skies and a light wind as surface high pressure builds in from the northwest should contribute to frost development at most locations along with freezing temperatures in the northeast. Forecast is on track and no changes were necessary. /22/ Prior discussion below: Tonight through Wednesday night: Latest RAP and satellite imagery showed a broad upper trough in the mid to upper levels of the atmosphere, which was providing cold air advection in northerly flow to the region. Under mostly sunny skies with some high clouds readings were mainly in the 50s. For tonight, expect another round of unseasonable temperatures as a 1027 mb surface high settles over the ArkLaTex region. This will cause light winds overnight under clear skies. Readings will dip into the upper 20s to the middle 30s. The coolest areas will be confined to our northeastern counties from Grenada to Kosciusko to DeKalb, where a freeze warning is in effect. This is the area that has the best chance of dipping below freezing for at least several hours. Have less confidence of this happening as we venture southwest from Meridian to Greenwood with frost expected. Across the remainder of the forecast area, low temperatures are expected to range from around 32 degrees to 37 degrees, with areas of frost possible. For Wednesday, a 1024 mb surface high will settle over the region. Light winds and cool air advection will bring another unseasonable day across the forecast area. Highs will range from the middle 50s north to the lower 60s south. Minimum humidities will dip in the lower to middle 20s, but light winds and recent rainfall will limit fire danger issues. As we move into Wednesday night, the 1023 mb surface high will settle over southern Mississippi. There will be some potential for freezing temperatures in our eastern counties for Wednesday night. So have issued a freeze watch for that area. Lows for Wednesday night will range from mainly the lower 30s east to the upper 30s west. Put in patchy frost across the east. Be sure to see the latest Hazardous Weather Outlook text and graphics, as well as Freeze warning/watch for more details./17/ Thursday through Monday: Amplified mid level pattern at the beginning of the period will begin breaking down moving forward as energy rotates out of base of trough along the west coast through the Rockies and into the western High Plains by Thursday evening. Meanwhile, surface high pressure will remain anchored over FL with resulting southerly flow serving to slowly moisten the lower levels. As the storm system moves further into the Plains Thursday night into Friday morning, increasing wind fields will rapidly initiate isentropic ascent over exiting cool airmass resulting in showers in the west by early Friday morning. Surface dewpoints will continue to rapidly rise as strong warm advection continues with mid 60s dewpoints in the ArkLaMiss Delta region by late Friday afternoon. Negative tilt of mid level cold core trough will support good mid level lapse rates. This coupled with 50+ knots of deep layer shear should support severe convection during the afternoon and evening and could linger into Saturday ahead of the approaching frontal boundary. Have continued the slight risk for the ArkLaMiss Delta region in the HWO. As the mid level system ejects out to the northeast Saturday night, trailing frontal boundary looks to hang up over southern sections with the next system approaching from the west Sunday. Warm advection in advance of this system will take advantage of the leftover surface boundary to initiate more convective development in the south by Sunday afternoon./26/ && .AVIATION... 00Z TAF discussion: VFR conds wl cont through Wednesday. /22/ && .PRELIMINARY POINT TEMPS/POPS... Jackson 33 58 33 71 / 0 0 0 0 Meridian 31 58 31 70 / 0 0 0 0 Vicksburg 34 59 35 72 / 0 0 0 0 Hattiesburg 32 62 34 71 / 0 0 0 1 Natchez 35 60 37 72 / 0 0 0 1 Greenville 32 56 38 69 / 0 0 0 0 Greenwood 31 55 37 69 / 0 0 0 0 && .JAN WATCHES/WARNINGS/ADVISORIES... MS...Freeze Watch from late Wednesday night through Thursday morning for MSZ029>033-037>039-044>046-050>052-056>058-065-066-074. Freeze Warning from 1 AM to 9 AM CDT Wednesday for MSZ026- 028>033-037>039. LA...None. AR...None. && $$ 17/22/26
Area Forecast Discussion
National Weather Service Louisville KY
950 PM EDT Tue Mar 13 2018 .Forecast Update... Issued at 945 PM EDT Tue Mar 13 2018 Numerous snow showers spreading southeast through southern IN and central KY currently, including some pockets of moderate to briefly heavy snow. Expect increasing traffic issues from this point forward over the next couple of hours. Areas impacted by a heavier burst of snow could see a half inch in as little as 15 minutes. Use caution if traveling late this evening. Some areas in the advisory area could certainly still get an inch, locally higher. The snow will be out of here by midnight. But as the snow showers are moving in, temperatures are dropping quickly due to evaporational cooling. After midnight, the rest of the night looks dry but cold. Wednesday morning lows will range from the upper teens to mid 20s. Use caution if traveling tonight. Sudden visibility reductions are also occurring in those heavier snow showers. Issued at 624 PM EDT Tue Mar 13 2018 Expanded the Winter Weather Advisory slightly to include Bullitt, Nelson, Marion, and Casey counties. Trends in the latest hi-res guidance have bolstered confidence we`ll see similar impacts from up to 1 inch of snow in parts of those counties. Certainly not everyone will get an inch of snow, due to the cellular nature of the snow showers. But that also means folks that do see a persistent snow shower could see locally up to 2 inches, mainly due to steep lapse rates and higher snow ratios by 03-06z tonight. In latest storm- total snowfall forecast, have the higher 1+ inch totals in northern and northeast Nelson and eastern half of Marion, so the risk for travel impacts is a bit higher in those areas. && .Short Term...(This evening through Wednesday night) Issued at 247 PM EDT Tue Mar 13 2018 ...Winter Weather Advisory This Evening/Tonight... A batch of scattered rain/snow showers is working through the Bluegrass region at this hour as a cold front also pushes through. Saw snow out of this precipitation with temps in the upper 30s, but don`t expect much in the way of accumulations given surface temps this afternoon. As we move through this evening (roughly 8 PM EDT to 2 AM EDT) a potent mid level shortwave will drop into the area, with steepening low level lapse rates and low to mid level saturation up through most (if not all) of the DGZ. Given the forcing, steep lapse rates, and good saturation think we`ll see numerous snow showers slide across southern Indiana, north central Kentucky, and into the Bluegrass region of east central Kentucky around and after sunset through just after Midnight. Expecting brief but intense bursts of snow where ratios should approach 20:1. Given surface temps around freezing, then falling below freezing as we approach Midnight, and good rates, think we`ll see some light accumulations. The main area of concern is along and east of a line from Salem, IN down through Louisville, KY and over to Richmond, KY where local amounts could be up to 1 inch. Spots that see the most persistent and intense snow showers could pick up a quick 1 to 2". Plan on issuing a Winter Weather Advisory to cover both the threat of brief/intense accumulations (impact-based) and the threat of localized amounts of approaching 2 inches. The Advisory will run from 7 PM EDT to 5 AM EDT tomorrow morning. Will probably be leaving some of the northern Bluegrass counties north of Lexington out of the Advisory as best coverage/intensity should be just south. Lexington will be included. Will also issue a Special Weather Statement around the advisory to cover the counties that could see around a half an inch or less of snow, but still intense bursts. Main messaging should be to watch for rapidly deteriorating conditions over short distances with snow bursts. Folks traveling along I-64 along and east of Louisville should especially be cautious, in addition to I-65 in southern Indiana down through Louisville and I-75 between Lexington and Richmond. These types of snow showers have been known to cause numerous accidents in the past. Main snow showers should move out shortly after Midnight with a cold and dry morning expected for Wednesday. After lows in the low to mid 20s, look for highs on Wednesday only struggling into the upper 30s and low to mid 40s SW. Dry conditions continue into Wednesday night with lows dropping around freezing to just above. .Long Term...(Thursday through Tuesday) Issued at 247 PM EDT Tue Mar 13 2018 Thursday - Thursday Night... Forecast remains dry for Thursday with dry NW flow aloft over us. However, the surface pattern will start to take on the shape of a loosely defined col over the region, signaling a developing frontal boundary near our SW CWA as we head into Thursday night. Will only mention small chances of rain across our SW on Thursday night as the front slowly becomes better defined. Highs Thursday will be around normal for this time of year in the mid and upper 50s in most spots. Locations along the TN border should sneak into the low 60s. Lows Thursday night are expected to range from around 30 in our NE, to around 40 in our SW down by the developing front. Friday - Saturday Night... A cutoff low will meander from the high Plains into the Mississippi and Ohio River Valleys by late Saturday. Ahead of this feature, precipitation is expected to increase in coverage along the stalled frontal boundary Friday into Friday night. By Saturday morning, surface high pressure will try to slide into the region from south central Canada, creating an overrunning scenario. Given the warm nose aided by a 20-30 knot low level jet, could see a brief freezing rain sounding until temps surge above freezing later Saturday morning. Will be something to watch in the coming days. The most widespread precipitation occurs from W to E on Saturday as the closed low opens up over our area and pushed ESE. We should then dry out Saturday evening as the system moves off. Highs Friday are only expected to be in the mid 40s to low 50s north of the boundary. Friday night lows range from the upper 20s NE to the upper 30s SW. Highs Saturday do find their way to near 50 in the NE and near 60 in SW as the warm front moves into the area. Saturday night lows drop into the 30s. Sunday - Sunday Night... Low amplitude upper ridging progresses through the area to end the weekend, bringing dry conditions and temps likely just above normal. Look for highs in the upper 50s and low 60s Sunday. Sunday night lows drop into the low and mid 40s. Monday - Tuesday... The beginning of the new week looks to be another wet stretch as models generally agree on a developing large storm system in the region. We`ll have to keep eyes on solutions as the potential for another phased storm isn`t out of the question. Early indications are that this storm system would be on the warmer side, to the point that we would have to worry more about thunderstorms than frozen precipitation (at least on the front side of the system). Lots to play out over the coming days. && .Aviation...(00Z TAF Issuance) Issued at 615 PM EDT Tue Mar 13 2018 Well...the brisk west winds continue to exceed guidance with strong caa mixing occurring and have raised the wind speeds gust through 02z. Obs at top of the hour showing several obs gusting into the 20- 25 mph range and SDF gusting to 27 mph. Despite a break in the action the cold sc/cu is coming into CWA with vort lobe rotating around Great lakes the 01-06z timeframe. Latest HRRR showing the snow showers expanding in coverage from with scattered to occasional snow showers at SDF and LEX roughly in the 01-05 UTC time period. Lapse rates are steep very steep indeed which will bring visibilities down in the moderate to heavy snow showers. These are not true traditional snow squall due to wind speeds <30 mph. Conditions should vary from VFR to low MVFR cigs depending on the intensity of individual snow showers. I expect vsbys in Snow showers to be 3-5 miles BUT there will be some 1/2 to 1 mile quick 5 minute bursts. Much of this activity should stay E of HNB, but still scattered flurries or light snow showers could affect HNB. Activity will stay N and E of BWG with VFR conditions there. Clouds begin to thin or clear out overnight and especially Wednesday morning with VFR conditions. Surface winds eventually back to a westerly direction during the day around 10 kts. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...Winter Weather Advisory until 5 AM EDT Wednesday for INZ077>079- 091-092. KY...Winter Weather Advisory until 5 AM EDT Wednesday for KYZ029>035- 038>041-045>049-054>057-066-067. && $$ Update...EBW Short Term...BJS Long Term...BJS Aviation...JDG
Area Forecast Discussion
National Weather Service Paducah KY
924 PM CDT Tue Mar 13 2018 .UPDATE... Issued at 924 PM CDT Tue Mar 13 2018 Remaining light precipitation should exit the northeastern section of the west Kentucky Pennyrile region within the next hour. Dry and cold (below normal) temperatures should prevail for the rest of tonight. UPDATE Issued at 601 PM CDT Tue Mar 13 2018 Updated Aviation Discussion for 00Z TAF Issuance UPDATE Issued at 545 PM CDT Tue Mar 13 2018 Minor sensible weather adjustments made for tonight and tomorrow. Moved the precipitation potential a little further east from 7 to 9 pm CDT across the eastern sections of southwest Indiana and into northwest Kentucky (generally east of a Princeton Indiana to Calhoun Kentucky line). Kept the majority of the precipitation a a trace mix of rain and snow. As the sub-cloud layer cools this evening, anticipate some flurries before ending altogether. Blended current forecast with the 3km HRR, SREF, 1 hour resolution of the 20 km GFS, and 13km RAP guidance to reflect subtle changes tonight into Wednesday. && .SHORT TERM...(Tonight through Thursday night) Issued at 1243 PM CDT Tue Mar 13 2018 Upper level low pressure core associated with Noreaster currently headed through New England will bring nwly flow to much of the region this afternoon through tonight. Within this flow may bring some 4kft cloud decks to mainly sw IN/nw KY, but any precip should remain east of our forecast area. Not as much cyclonic flow expected Wednesday, but still may be some afternoon cumulus around/east of the MS River during the afternoon. Main weather feature to take over the remainder of the short term will be the development of a blocking mid/upper level Omega high pressure system over the Continental Divide and and into the western Plains by Thursday. This should allow for plenty of sunshine and warming west to southwest winds, with temps finally getting back above normal into the upper 50s to mid 60s. Should ne a fairly nice afternoon for mid March. .LONG TERM...(Friday through Tuesday) Issued at 241 PM CDT Tue Mar 13 2018 The deterministic medium range models were in better agreement currently than 24 hours ago. The general consensus is that there will be two separate closed lows ejecting from persistent eastern Pacific/CA shortwave energy, moving across the PAH forecast area in the extended forecast period. The forecast period will start out with a good signal for the formation of a west-east surface boundary across the PAH forecast area, ahead of the first impulse. Rain showers appear likely early Fri as the front begins to push southward. At the same time, low level moist fetch should be enabled, and this moisture will ride up over the shallow wedge of cooler air that will be sustained by easterly surface winds. This should result in the best QPF through at least the morning hours Fri. Isolated lightning strikes might occur near the AR/TN state lines mainly Fri night under enhanced mid level positive vorticity advection. As the impulse continues eastward, drier air should eventually begin to move into our region from the southwest later, limiting pcpn, but the timing of this is a bit uncertain (Fri afternoon? Fri night?). This was dependent on the progged position of the first tight, nearly stacked low pressure system moving out of the central Plains (the CMC seemed to have a more unlikely, more northerly path). There are signs that the low may begin to weaken as it moves by just to the north of our region, thus the QPF should be light for us into Sat, with conditions stable enough to probably preclude thunder. The latter half of the weekend appears dry at this time under quasi- zonal flow aloft. The second impulse will approach our region from the west Sun night, trailing a surface pressure trof/cold front south of it. At this time, fropa is forecast to occur Mon afternoon or Mon night. PoPs remain in the chance category for Tue (Day 7) due to the possibility of the mid/upper low lingering in our region. The trend lately has been toward cooler temps, staying in the general vicinity of seasonable numbers. && .AVIATION... Issued at 601 PM CDT Tue Mar 13 2018 Diurnally enhanced cu field in northeast (KEVV/KOWB) should dissipate with loss of fuel, scattering mid (VFR) bases by mid evening. Gusts may maintain until almost then, and then should diminish as skies clear all sites. Nwlys will return tmrw, not as gusty, then back during the day, with perhaps some scattered high clouds at times. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$ UPDATE...Smith
Area Forecast Discussion
National Weather Service Sacramento CA
300 PM PDT Tue Mar 13 2018 .SYNOPSIS... Series of Pacific storms will move through this week bringing periods of rain and mountain snow, heavy at times, with gusty wind and thunderstorms. && .DISCUSSION... Pacific frontal system moving into the eastern foothills and mountains this afternoon. Lines of stronger returns are being observed on 88D Mosaic with embedded thunderstorms extending from the West Slopes of the Northern Sierra Nevada through the Motherlode, into the San Joaquin Valley. HRRR showing heavier precip continuing in the Motherlode and Sierra throughout most of the night. Snow level radar indicating snow level above 8000 feet at Colfax but is lowering at Chico and Oroville to 5700 feet as colder air is ushered in behind front. Expect snow levels to drop below pass levels this evening, then continue to lower overnight to 3500 to 4500 feet by Wednesday morning. Periods of heavy snow and strong wind expected in the Sierra overnight. Showers continue over Interior NorCal Wednesday as upper level trough moves through. Periods of moderate snow showers expected in the Sierra Wednesday. Models showing significant amount of CAPE at the lower elevations tomorrow afternoon to include thunderstorms in the forecast. Stronger storms likely to produce some hail. Upper trough shifts through Wednesday night with showers decreasing overnight into early Thursday. Models then show channeled vort moving into the area Thursday afternoon into night. Snow expected to ramp up in the mountains Thursday afternoon into night. Main upper low digs along the NW CA coast Friday with additional waves rotating into the area. Showers and thunderstorms likely Friday with continued periods of heavy snow in the mountains. Snow levels continue around 3000 to 4000 feet, but could be down to 2500 feet in heavier convection. Have added Winter Storm Watch for this next system. Snow advisories may also be needed for the Coastal and Shasta mountains late Thursday and Friday. PCH && .EXTENDED DISCUSSION (Saturday THROUGH Tuesday) Precipitation could continue across interior NorCal on Saturday as a weak upper disturbance pushes through the area. Drier weather will return Sunday into early Monday as ridging attempts to rebuild. Active pattern returns early next week as an upper level system drops down into the Eastern Pacific and move into the West Coast. However, there are model differences in timing and evolution of this system. The GFS begins to spread precipitation as early as Monday afternoon, while the ECMWF holds off until Monday evening. In addition, the GFS digs the upper system southward and ends precipitation faster than the ECMWF. Regardless, confidence is high that the unsettled weather pattern will continue through at least the middle of next week. && .AVIATION... Storm system will continue to bring MVFR/IFR conditions across Valley TAF sites, and IFR/LIFR conditions over the mountains. South winds 10-20 kt with gusts to 30 kt across the Valley will continue through 01z Wednesday. && .STO WATCHES/WARNINGS/ADVISORIES... Winter Storm Warning until 5 PM PDT Wednesday for West Slope Northern Sierra Nevada-Western Plumas County/Lassen Park. Winter Storm Watch from Thursday afternoon through Friday evening for Western Plumas County/Lassen Park. Winter Storm Watch from Thursday afternoon through late Friday night for West Slope Northern Sierra Nevada. && $$
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday) Issued at 340 PM CDT Tue Mar 13 2018 Little sensible weather is forecast for tonight and tomorrow with the biggest challenges of the forecast revolving around temperature trends. A strong upper level omega block was anchored over the Rockies early this afternoon in water vapor imagery with a 1033 mb surface high pressure cell building southward into the Central Plains. This setup will bring clear skies for tonight as the high moves overhead. A dry tongue was associated with this ridge, with dewpoints falling into the single digits above/below 0 F from Salina northward into Central Nebraska. Leveraged the recent HRRR runs to model this wedge of dry air for tonight and early tomorrow as most guidance was far too moist. The combination of clear skies, light winds, the very dry air, and little soil moisture will cause temperatures to plummet tonight into the 20s and even upper teens. Went close to the MET guidance for lows, with a similar setup last week resulting in lows that were 5+ degrees cooler than most solutions. Wednesday will feature clear skies and increasing SW winds as the surface high departs and the surface pressure gradient over the state increases. There is some concern that the wedge of dry air may linger through part of the day before increasing moisture overspreads the region. Warmer downslope air overspreads the region on Wednesday, allowing highs to surge into the upper 60s to low 70s in most locations. The combination of increasing/gusty winds and low RH values will present a widespread very high fire danger day throughout NE Kansas. .LONG TERM...(Wednesday night through Tuesday) Issued at 340 PM CDT Tue Mar 13 2018 The chance of precipitation creeps back into the forecast for late in the week with temperatures at or above normal--the exception possibly being Friday. Thursday will be a near carbon-copy of Wednesday temperature-wise with H850 temps in the +8 to +10 C range and surface temps in the 70s. Some locations in central Kansas could push the upper 70s closer to the H850 thermal ridge. The surface flow turns slightly more to the south, advecting increasing amounts of moisture into the region and reducing the fire weather risk. A baroclinic zone develops over the state during the course of the day as lee cyclogenesis takes place over the Front Range in response to an approaching H500 vort max. Winds on Thu night into Friday look to remain on the strong side given the 20-40 ubar/km pressure gradient over the region. NAM/GFS forecast soundings show a shallow mixed BL throughout the night with winds of 15 to 25 kts throughout this layer. Increasing 295-305 K isentropic upglide over the effective lower tropospheric warm front will fuel elevated showers and possibly a few thunderstorms over NE Kansas overnight Thu/early Fri morning. However, forecast soundings and MUCAPE plots are rather unimpressive and only kept slight chance of thunder mentioned in the forecast. Recent runs of the EC/GFS have come into some agreement in the position of the warm front for Friday--bisecting the CWA from NW to SE. Highs therefore on Friday could vary greatly between the upper 40s on the KS/NE border to the upper 60s by Emporia. The dry slot punches northward over the CWA by midday Friday, likely bringing an end to any widespread precip. A light drizzle is possible north of the warm front Friday night into Saturday morning before the low pulls out. While it is quite a ways out to nail down any top-down forecast parameters, the current synoptic setup would support a small window of freezing drizzle near the KS/NE border early Saturday morning. Did mention this possibility in the grids but it is of very low confidence at the present time. After the departure of this system on Saturday morning, an active zonal flow pattern will set up for the weekend and early next week. However, confidence in the timing and locations of these late period systems is low. The next decent chance of precip after Sat morning possibly arrives Sun night. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 545 PM CDT Tue Mar 13 2018 VFR conditions are forecast to persist through the period with light winds overnight becoming southwest with some gusts after 15Z Weds. && .FIRE WEATHER... Issued at 340 PM CDT Tue Mar 13 2018 Northerly winds today lessen tonight and then switch to the SW by sunrise on Wednesday. These winds increase to between 10 and 15 mph with gusts near 25 mph at times on Wednesday. Dry air currently in place over the state slowly moistens during the day on Wednesday, but widespread very high fire danger conditions are still forecast during the day. Currently forecast RH/wind conditions are straddling the extreme fire danger category for Wednesday and there is a chance that, should conditions deteriorate any further, that a Red Flag Warning may be issued. For Thursday, southerly winds lessen slightly and RH values will also be somewhat higher, limiting the areal extent of the very high fire danger threat to along and west of the Flint Hills in the afternoon. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Skow LONG TERM...Skow AVIATION...Omitt FIRE WEATHER...Skow