Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/06/18

Area Forecast Discussion
National Weather Service Charleston SC
910 PM EST Mon Nov 5 2018 .SYNOPSIS... A warm front will lift north of the area Tuesday. A cold front will move into the region Tuesday night. The front will become stationary over the area Wednesday into late week. A stronger cold front will cross the area by Saturday, followed by a cool high into early next week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... 06/02z surface map placed the warm front over the southern Midlands, CSRA into central Georgia with all of Southeast South Carolina and Southeast Georgia embedded within the warm sector. Dewpoints remain in the upper 60s/lower 70s, indicative of a very warm and humid airmass for early November. Expect a mostly dry night to prevail, although an isolated shower or two could certainly develop at just about any time given the moisture levels that are in place. Maintained 20% pops through the overnight period. The main forecast concern centers on the potential for widespread fog and stratus. GOES-E fog product shows widespread stratus with areas of fog have developed across much of the interior within a large clearing band between two areas of cirrus. This area of clearing will contiue to march to the coast, so expect fog and stratus to build east. Later tonight, southeast winds are expected to increase, which will tend to erode any fog and status from southeast to northwest. This trend was captured well in earlier runs of the RAP and H3R and matches output from the latest NARRE-TL. Best chances for dense fog look to remain across interior Southeast Georgia, especially from Reidsville- Millhaven and points west for most of the night, although patchier dense fog could occur just about anywhere before the southeast winds increase. Temperatures will not change much more given the high dewpoints in place. Nudged lows up a degree per current trends with most areas only bottoming out in the upper 60s/near 70. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Tuesday: A warm front will lift north of the region. We will start the morning with areas of fog and perhaps a few showers, especially along the coast. Then, ahead of an approaching cold front, convection should develop upstream and push into the region during the afternoon. Between these episodes, precipitation coverage should remain sufficiently to allow temperatures to recover into the lower to mid 80s away from the beaches, well above normal for early November and not far from record highs at KCXM and KSAV. A marginal risk for severe thunderstorms encompasses a large swath of the forecast area Tuesday afternoon and evening. Strongest forcing for ascent and the associated greater risk for severe thunderstorms is expected to pass north and west of the region. However, sufficient instability/shear could develop to support isolated damaging wind gusts within multicell clusters of thunderstorms during the afternoon/evening hours. Nevertheless, unless thermodynamic/kinematic parameters vary significantly from forecast values, a significant severe weather event appears unlikely. Tuesday night into Wednesday: A weakening/slowing cold front will push into the region. This will maintain at least isolated/scattered showers, and isolated thunderstorms cannot be ruled out Tuesday evening and again Wednesday afternoon. Also of note, the shallow push of cooler air into a moist environment could support another round of significant stratus/fog later Tuesday night into Wednesday morning. Otherwise, expect Tuesday night low temps ranging from 60- 65F inland to around 70F on the beaches, followed by Wednesday high temps in the middle/upper 70s north to the lower 80s south. Wednesday night: By this time, the cold front will have stalled/transitioned to a stationary front just south of the region, and an associated baroclinic zone will set up over the area. Meanwhile, a shortwave trough is progged to cross the region while enhanced low/mid level moisture transport contributes to increasing low-mid level moisture/PWAT values 1.75-2 inches. As a result, expect precipitation coverage to ramp up. Latest PoPs are graduated from high chance inland to likely elsewhere. Higher PoPs could eventually be required. Also, will continue to assess the potential for another round of significant stratus/fog. Thursday: Deep-layered moisture and associated elevated PoPs will persist, and latest PoPs range from chance inland to likely south/east. the axis of deep moisture could push south/east of the region as the shortwave trough exits Thursday afternoon, but this solution remains uncertain. Wednesday night and Thursday: Elevated high tide levels and rain could produce Advisory level flooding in some coastal locations, including downtown Charleston, especially around the times of the evening and morning high tides. && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... A relatively wet period is in store Thursday night through at least Friday night, potentially lingering into Saturday morning as the front remains stalled over the area and several low pressure waves move along it. Fairly good model agreement that cool, dry high pressure will expand over the area late Saturday through Sunday, though another system could potentially affect our area early next week. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... KCHS: MVFR cigs are expected to fill back in by mid-evening with a period of IFR cigs and possibly some fog in the 03-06z time frame. High resolution guidance then pushes the IFR or lower conditions west of the terminal as southeast winds increase. MVFR Cigs will prevail for much of the night before increasing to MVFR by mid-morning. Confidence is low to moderate on how low clouds and fog will evolve this evening. KSAV: Fog and stratus are expected to redevelop over the terminal overnight, but there are signals that as southeast winds increase, lower vsbys could be pushed back to the west. Maintained IFR cigs redeveloping overnight, but limited fog to MVFR thresholds for now. Cigs were capped just above alternate minimums. Confidence is low to moderate on how the fog and stratus situation will evolve overnight. Extended Aviation Outlook: Low-level moisture and precipitation are expected to create periodic flight restrictions of varying magnitude at both terminals through Friday. && .MARINE... Tonight: SSE winds 5-10 kt in the evening will gradually transition to the S or maybe even SSW by daybreak while increasing to 10-15 kt. Seas will average 2-4 feet, with some 5 footers possible in the offshore GA waters late. Additionally, land fog could seep towards Charleston Harbor later at night, possibly causing visibility reductions. But confidence is not yet high enough to put patchy fog in the Charleston Harbor forecast. Tuesday through Saturday: This period will feature frequent wind shifts. Southwest winds as high as 15-20 knots and seas of 3-5 feet will prevail Tuesday/Tuesday evening. Then, a cold front will turn winds to the to northwest then northeast around 10 knots, accompanied by seas of 2-4 feet, Later Tuesday night into Wednesday. passing low pressure will turn winds toward the southeast Wednesday night then toward the northeast Thursday/Thursday night. Of note, winds/seas could approach Small Craft Advisory levels in some areas Thursday/Thursday night. Ahead of a stronger cold front, expect winds to become southeast Friday, then winds will abruptly shift to the north/northeast as the cold front passes and cooler high pressure builds over the waters later Friday night/Saturday, and Small Craft Advisory conditions are expected in most/all areas. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$
Area Forecast Discussion
National Weather Service State College PA
830 PM EST Mon Nov 5 2018 .SYNOPSIS... A strong frontal system will sweep through the region on Election Day. Our active weather pattern will continue with only a short break Tuesday night into early Thursday, before another storm system moves in for late in the week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... The dreary day has continued into the now earlier evening with widespread low clouds and areas of mainly light rain and drizzle. The HRRR shows the rain diminishing but forecast soundings show the low levels remaining saturated with a light SSE flow, so look for the damp conditions to continue right up until the time rain overspreads the region ahead of the approaching frontal system just after sunrise. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/... The cold front will speed across the CWA Election Day. All guidance shoves the bulk of the precip off to the east of the area by noon with the front roughly EWR- PHL- IAD at 18Z. Only the far SERN sliver of counties could have thunder chc continue into the aftn if the front drags along. SPC continues to outlook that area with a SLGT risk, with a buffer of MRGL risk to the NW about 2 counties deeper into the CWA. If timing continues to look like the current fcst, this may be too far north/west. Rain does look heavy at times but QPF has been lowered. So while soils are saturated and the system is moving fast, there is a marginal risk for localized flooding. While most of them would be minor, a few of the river points could experience significant rises, esp the tribs flowing directly into the Lower Susq. The brunt of the cold advection seems to pass to our north. The fetch off the lakes looks like it would take any lake enhanced showers Tues night off to our north into wrn NY. Clouds will linger into the night over the Alleghenies, but might be gone by Wed AM. && .LONG TERM /TUESDAY NIGHT THROUGH MONDAY/... Moderately tight LLVL P-gradient in the wake of the cfront will help to create gusty WNW winds and cooler air for Tuesday night right into Thursday. The falling temps and veering cross-lake fetch will bring some lake effect rain showers down into the NW part of the CWA, and could allow for some wet snow with minor accums of a coating on the higher elevations Wed night as temps dip to near freezing. mins elsewhere will be mainly in the l-m 30s. Subsidence inversion base is within 4 kft agl, and cloud temps generally AOA -6 to -8C, so QPF from the LER/S should be light. Elsewhere, the period Tuesday night through early Thursday night will afford generally dry conditions with temps near to a few deg F above normal Wednesday, then slightly lower heights aloft/thicknesses will help drop daytimes max temps to at least several deg F below normal on Thursday with maxes mainly in the 40s and l50s. Interesting pattern for Friday with a good chc for mainly clear skies initially over the NE half of PA, and relatively cold air in place - at least at LLVLs as 1030 mb sfc high pressure drifts just NE of the state. A nrn stream wave tries to phase with srn stream moisture. A low develops in the Coastal Carolinas and heads NE. Many GEFS members generate what could be a few hour period of accumulating snow (or at least the threat for mixed precip) for the nrn Alleghenies Fri/Fri night, and mainly rain following a brief period of wet snow or mixed precip elsewhere. Latest 05/12Z operational runs of GFS and EC remain supportive of this too, though the thickness fields and onset timing of the precip later Friday morning paint less of a threat for frozen precip. A return to brisk, chilly and generally dry weather with just some minor LES mixed rain/snow showers across the NW mtns will follow for Sat into next Monday. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... A moist southeast flow over central Pa will result in predominantly ifr/lifr cigs overnight. Some places are still reporting mvfr cigs early this evening, but some modest nocturnal cooling should cause even those locations to transition to ifr cigs later tonight. A frontal boundary will push through the area between 15Z-20Z, preceded by several hours of rain, continued low cigs and possible llws. Behind the front, expect clearing skies with a rapid improvement to vfr and increasingly gusty southwest winds Tuesday afternoon. Model soundings support afternoon gusts of 25-30kts over northwest Pa and 15-20kts across the southeast part of the state. .Outlook... Wed...Gusty west winds possible. Thu...No sig wx expected. Fri...Rain/low cigs/llws possible. Sat...No sig wx expected. && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo/La Corte NEAR TERM...La Corte/Ceru SHORT TERM...Dangelo/Ceru LONG TERM...Lambert AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Grand Rapids MI
647 PM EST Mon Nov 5 2018 LATEST UPDATE... Aviation .SYNOPSIS... Issued at 309 PM EST Mon Nov 5 2018 Steady rain moves in tonight and lasts through tomorrow morning before fading to lighter showers. Gusty winds will likely develop on Election Day, starting late in the morning and lasting into the afternoon. A mix of rain and snow may impact the lake shore region mid week with minor impacts expected. Snow showers will likely impact our region Friday into early Saturday with some accumulations possible as a cold blast of air moves in. After a short break, another shot of cold air and some snow showers may be in the offing for early next week. && .DISCUSSION...(This evening through next Monday) Issued at 309 PM EST Mon Nov 5 2018 The main items of interest continue to center on wind gust potential on Tuesday along with a transition into a wintry pattern later this week and into the weekend. Rain still looks on track for tonight into Tuesday morning as an area of low pressure approaches Chicago and eventually tracks over Lake Michigan and deepens as it heads northeast, likely around 992 mb over Lake Huron by Tuesday morning or early afternoon. A general half inch to three quarters of an inch of rain is expected with this system. More impressive than the rainfall will be the winds generated by cold air advection sweeping through the region on the back side of the low. Mixing heights don`t look terribly impressive, likely on the order of 1500-2000 ft or so, but it won`t take much to mix down strong wind gusts. Model soundings reveal a fine line between 30-40 mph sfc gusts and 40-50 mph, based on the depth of mixing and how strong the 925-850 mb winds are. This varies by model in spite of overcast skies limiting the depth of mixing. For example, the NAM 3km has a more conservative mixing height during the late morning and afternoon while the RAP is more aggressive. This makes the difference in power outage potential and hence whether we need a Wind Advisory or not for Tuesday. Our in-house blend of models indicates 30-40 mph will be the most likely (particularly near and south of I-96), and this seems like a reasonable compromise given model differences in mixing heights. The strong winds may begin as early as mid to late morning and last through the afternoon. Some branches may come down and there may be some isolated power outages on Election Day. We will keep an eye on trends. Light rain and snow showers are possible Wednesday into early Thursday along the lake shore and by U.S. 10 as well, with generally limited impacts expected, although some snow may stick Wednesday night with perhaps some slick spots east of Ludington and Pentwater and toward Reed City and Baldwin. Models continue to advertise -10C to -15C at 850 mb later Friday into Saturday as a fairly strong 500 mb shortwave trough zips through the Great Lakes region. This may help lift a weak area of low pressure into Ohio that could bring light snow to the region, possibly mixed with rain to start (before the colder air arrives). Temperatures initially in the mid to upper 30s will quickly fall to below freezing in the evening and continue their descent into the low to mid 20s Friday night. Lake effect snow showers look likely Friday evening and into Saturday morning. Conservatively taking -12C at 850 mb over the lake would yield delta Ts of over 20C, given current lake surface temperatures. Looking at RH and omega within the -12C to -18C (DGZ), the FV3 is showing favorable conditions near and west of U.S. 131 for lake effect snow bands Friday evening and Friday night. The heaviest snow may end up staying further north of our region toward Grand Traverse Bay and toward Grayling/Gaylord. Nevertheless, at least some light accumulations are possible for our traditional northwest flow regions. Rising heights on Saturday should shut off the snow showers but we may struggle to reach the mid 30s. The cold air may last into early next week (perhaps worsen?) with additional periods of lake effect snow showers. The ECMWF/GFS/FV3 are in general agreement with this pattern though the GEM is not. At this point, the odds currently favor below normal temperatures and occasional snow showers. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 647 PM EST Mon Nov 5 2018 A developing storm system will track into the Southern Great Lakes tonight and the center of the storm will track through the Detroit area during the mid morning hours of Tuesday. This storm will bring a variety of hazards tonight to Southwest Michigan. Expect moderate to heavy icing above 9000 ft agl tonight and above 7000 ft agl Tuesday during the day. Also expect moderate to severe turbulence above 7000 ft tonight into the mid morning hours of Tuesday. During the day Tuesday the strong winds will cause moderate to severe mechanical turbulence. Beside those hazards a band of moderate to locally heavy rain will develop and move across our TAF sites in the 04z to 09z time frame. The MKG and GRR taf sites should see the heaviest rain and thus the lowest cigs/vis... LIFR is more than possible. Once the occluded front comes through around 12z winds will become southwest and increase in speed. The steady rain will end but shows and IFR/MVFR conditions will likely prevail into the evening. All sites will see wind gusts in the 25 to 35 knot range during the day hours but the LAN and JXN taf sites may see gusts to near 40 knots. && .MARINE... Issued at 309 PM EST Mon Nov 5 2018 The SCA continues through 7pm this evening and we have gone ahead with the Gale Warning (all zones) for Tuesday and Tuesday night. The highest winds will likely be south of Whitehall with this event where over 40 knots may be commonplace. Waves may reach or even exceed feet with this event. Even though winds subside below gales on Wednesday, waves will remain high, on the order of 6 or 7 feet potentially. && .HYDROLOGY... Issued at 1031 AM EST Mon Nov 5 2018 Rain through Tuesday night will likely cause within bank rises on area rivers, but no rivers are expected to rise above flood stage. We may see some ponding of water however, especially in low-lying and poor draining areas by Tuesday. Up to a half inch of rain fell last night into this morning. This afternoon should be dry, but another round of rain will lift across the area tonight and Tuesday. Rain may be heavy at times. Rainfall totals with this system look to range between 0.5 and 1.0 inches. Lake-effect showers will occur from Tuesday night into the weekend. Rain/snow amounts look fairly light through Thursday night, but we may see some snow accumulations Friday and Saturday. This should have little impact on area rivers, and temperatures will not yet be cold enough to worry about rivers freezing or ice jams forming. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...Small Craft Advisory until 7 PM EST this evening for LMZ844>849. Gale Warning from 7 AM Tuesday to 1 AM EST Wednesday for LMZ844>849. && $$ SYNOPSIS...Hoving DISCUSSION...Hoving AVIATION...WDM HYDROLOGY...63 MARINE...Hoving
Area Forecast Discussion
National Weather Service Jacksonville FL
752 PM EST Mon Nov 5 2018 .UPDATE...Radar continues to show a few showers and isolated thunder across se GA...and virga/sprinkles with higher clouds across ne FL. Recently, radar has shown an increasing area of showers over the NE Gulf of Mexico and the westernmost counties of the northern FL peninsula. The latest HRRR suggests, although late by a few hours, these showers will spread E and NE across NE FL thru 06z...then offshore after 06z. Have updated the hourly POP/Weather grids to reflect this evolution...with decreasing showers further north. Current mild low temperature forecast Tonight supported by latest consensus guidance. && .AVIATION...Maintained potential for showers and MFVR CIGs thru 04Z in latest TAFs...though that may need to be extended beyond 04Z for easternmost TAF sites. May see patchy light fog across the TAF sites, but potential for more significant fog appears less than last night per latest guidance. && .MARINE...No significant changes planned in next CWF issuance. Moderate southerly flow expected through Tuesday with 2-4 ft nearshore seas and 4-5 ft offshore seas. Rip Currents: A southeasterly ocean swell will reach area waters on Tuesday, keeping a moderate risk in place through at least midweek. && .PRELIMINARY POINT TEMPS/POPS... AMG 68 83 67 81 / 20 50 30 50 SSI 70 81 69 80 / 30 20 30 30 JAX 70 85 69 84 / 30 20 20 30 SGJ 71 83 71 83 / 30 10 10 30 GNV 69 85 67 86 / 30 20 10 30 OCF 69 86 67 86 / 20 10 10 20 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ Wolf/Bricker
National Weather Service Jackson KY
1042 PM EST Mon Nov 5 2018 .UPDATE... Issued at 1042 PM EST MON NOV 5 2018 The initial slug of showers is now moving across portions of the Bluegrass at this late evening hour. The amounts have generally been in the quarter of an inch pre hour range. The line of convection we have been discussing for many days now has developed and is pushing east into south central Kentucky this hour. This did prompt a mesoscale discussion from the SPC discussing mainly the wind threat, since you can see some bowing segments embedded within this line. The chances of seeing this will be mainly toward the Lake Cumberland region based on the radar trends and should make it into this area by around 6Z to 7Z timeframe. We have seen some instances of gusty winds out ahead of the convection mainly in the 20 to 30 mph range, but some higher gusts remain possible even ahead of this line of showers and thunderstorms. There is some potential for isolated flooding of low lying areas, but the overall forward speed of this is expected to pick up and this should mitigate more widespread issues. Updated the grids to better reflect the latest radar trends and hires guidance trends. Also, still seeing some temperature splits in the far east, but as winds increase temperatures will rise closer to the rest of the area. UPDATE Issued at 718 PM EST MON NOV 5 2018 The latest scans of the WSR-88D shows an area of showers and thunderstorms moving into portions of western and central Kentucky this evening. This activity has been slow to progress east as the upper level trough become more negatively tilted across the Midwest. The HIRES models are in good agreement taking this initial slug of moisture northward and bring a line of showers and thunderstorms through the region late this evening into the overnight hours. The HRRR might be a little slower in the latest runs and this will have to be monitored for subsequent updates. Did introduce higher POPs a little earlier north of I-64, with this initial slug of moisture. Otherwise more minor adjustments to the overall POPs at this time. Now in terms of winds, they have been slow to mix down in the western portions of Kentucky, and the models may be a little overdone on the jet at this time based on some of the VAD wind profiles. Either way it will only take on decent storm or heavier shower to mix down the stronger winds aloft through the late evening and overnight. Finally, the only other issue addressed this evening is the clouds are not keeping the far east from decoupling this evening and made some adjustments to the temperature curve to better handle this idea. && .SHORT TERM...(This evening through Tuesday night) Issued at 459 PM EST MON NOV 5 2018 Late this afternoon, low pressure was developing over the mid Mississippi valley. In the mid/upper levels, an associated impulse was rotating through a large longwave trough over the CONUS. The surface low will rapidly deepen as it moves north to the Great Lakes as its associated upper level support ripples through the larger scale trough. The low will propel a cold front east through KY, with advection of mild/moist air occurring ahead of it, underneath the advancing impulse. This will produce showers as the cold front moves in tonight, and possibly some thunderstorms. Deep layer instability will be weak. However, shear will be exceptional, with an abundance of strong winds aloft. This will present a threat of strong/damaging winds should the convection be able to mix environmental flow aloft to the ground. The main factor seems to be whether the lack of significant surface based instability can be overcome in order to get winds to the surface. Even outside of thunderstorms, it will become breezy, especially as the cold front pushes through. Some showers could linger into Tuesday morning, but will end quickly, as surface ridging builds in from the west and southwest and provides fair weather through the remainder of the short term period. .LONG TERM...(Wednesday through Monday) Issued at 459 PM EST MON NOV 5 2018 The models are in good agreement with the upper level pattern for the extended. A wave will move through Wednesday, bringing the possibility for showers mainly for southeastern Kentucky into the afternoon and through the evening. Near-zonal conditions will then take hold until late week when a northern stream trough moves over the central CONUS towards the Ohio Valley. This trough will move through the Ohio Valley Friday and into early Saturday. Closer to the surface, high pressure will dominate until a cold front moves through Friday. This, along with strong upper level dynamics, will bring at least likely PoPs for eastern Kentucky Friday morning and into the afternoon, decreasing through the evening. High pressure, and thus drier conditions, will again take hold for the remainder of the weekend. Another system will approach the Commonwealth Monday, but as this is at the end of the forecast period, there is greater uncertainty. Future model runs will be monitored for the development of this system. High temperatures will begin in the mid to upper 50s Wednesday, but then be on the decrease through late week. After the passage of the cold front later on Friday, highs Saturday will range from the low to upper 40s. Highs will then generally be around 50 degrees into the start of next week. Low temperatures will be below normal throughout the period, with the coldest lows occurring Saturday and Sunday mornings. Also, due to clear skies and light winds, have included the potential for ridge/valley temperature differences Thursday and Sunday mornings. Colder valleys are possible Saturday morning as well, but greater surface winds with frontal passage may inhibit the decoupling of valleys. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) ISSUED AT 621 PM EST MON NOV 5 2018 The period is starting off VFR ahead of an approaching strong storm system. However, conditions will worsen as showers and thunderstorms along and ahead of a cold front progress toward and move across eastern Kentucky tonight. The CIGs and VIS will drop to MVFR, with IFR possible at times in heavier showers and thunderstorms late this evening through tonight. There is a strong low level jet associated with this system, and despite the elevated winds at the surface added some LLWS to all the TAF sites this evening into tonight. That said, winds will be most gusty in heavier showers and thunderstorms along and near the cold front, with gusts of 20 to 30 knots possible at times. It will remain gusty even into Tuesday with gusts of 15 to 20 knots through the day. The TAFs will return to VFR by late Tuesday morning into Tuesday afternoon. && .JKL WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...DJ SHORT TERM...HAL LONG TERM...CGAL AVIATION...DJ
Area Forecast Discussion
National Weather Service Marquette MI
650 PM EST Mon Nov 5 2018 .SHORT TERM...(This evening through Tuesday) Issued at 259 PM EST MON NOV 5 2018 WV imagery and RAP analysis indicated a mid/upper level trough through the central CONUS. An upstream shortwave trough and associated sfc low was moving into western IA. Rain associated with this feature was gradually lifting northeastward from IA and srn MN. Otherwise, despite weak sfc riding moving into the area from nrn WI, abundant low level moisture persisted below a 3k-4k ft inversion. Tonight, the models suggest that the pcpn will continue to gradually spread into mainly the west and south by late this evening. There is more uncertainty with how far or quickly the pcpn will spread into the rest of Upper michigan overnight. So, only chance POPs were included over the north and east. Forecast wet-bulb zero heights suggest that any pcpn will fall predominantly as rain despite temps remaining nearly steady in the mid 30s over the inland west. Overall rain amounts will remain light, generally at a tenth of an inch or less. Tuesday, the strongest isentropic lift and 700-300mb qvector conv associated with the shrtwv and sfc low is expected to remain well to the southeast of Upper Michigan. However, areas of rain should still persist through the day as sfc troughing and weaker 700-300mb qvector conv remain over the area ahead of another shrtwv moving out of the nrn Plains. There may be periods through the day, especially north central, where there is little measurable rain, with just some patchy drizzle. .LONG TERM...(Tuesday night through Monday) Issued at 302 PM EST MON NOV 5 2018 Busy extended forecast with the first good shot at accumulating lake effect snow showers later this week and chances for widespread precipitation as multiple systems track across the Upper Great Lakes. Each of these systems will bring bouts of colder air down from Canada. By the end of the work week and into this weekend day time highs will struggle to reach the freezing mark, with overnight lows expected down into the teens. During times when colder temperatures combine with gusty winds, it certainly may become blustery at times. Wednesday through Friday, widespread lingering rain and snow are expected as upper-level energy continues to slowly exit the region. Behind this system, as 850mb temperatures cool down to around -8 to - 10C, lake enhanced snow showers will develop across the northwest wind snowbelts downwind from Lake Superior. With lake induced instability increasing and lingering large-scale lift, wouldn`t be surprised if the lake effect snow falls moderately at times. Later Wednesday night through the day Thursday, 850mb temperatures cool further to around -11 to -13C. This will favor an uptick in the intensity of ongoing lake effect snow showers. Late Thursday, lake effect snow showers across the west half will push offshore as flow backs southwesterly ahead of a troughing pivoting east across the region. Still expect lake effect snow to linger across the east half where flow will be slower to respond to this change. As the trough pushes eastward on Friday, large-scale lift will increase and allow for another chance for light snow across much of the area. With even colder air progged to arrive behind this system late Friday, should see efficient, moderate to perhaps heavy lake effect/enhanced snow and the potential for some blowing snow, after it starts to accumulate on the surface, near Lake Superior where gusty northwest winds are possible. This weekend into early next week, there is quite a bit more uncertainty in how things will unfold with yet another system progged to track across the Upper Great Lakes. Regardless, there will be moderate to perhaps heavy lake effect snow showers ahead of and behind this system, mainly across the northwest wind snow belts. Where snow has accumulated on the ground, could see some issues with blowing snow arise if the arrival of cold air and breezy northwest winds come to fruition early next week. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 649 PM EST MON NOV 5 2018 MVFR conditions will prevail thru the evening at KIWD/KCMX/KSAW. With a low pres system tracking ne into the Great Lakes tonight into Tue morning, -ra will spread into the area, beginning first at KIWD this evening, and then potentially at KCMX/KSAW overnight. Along with the -ra, expect conditions to fall to IFR at KIWD overnight and at KSAW Tue morning. IFR or low MVFR conditions will be the rule on Tue under ocnl -ra. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 259 PM EST MON NOV 5 2018 No gale events are expected through Thursday. Winds will continue to diminish tonight to less than 15 knots Tuesday as the pressure gradient relaxes with broad troughing expected to develop over Lake Superior. Winds become northwesterly 20 to 30 knots Tuesday night through Thursday as colder air moves through the northern Great Lakes. From Friday into the weekend, north to northwest gales could develop with a stronger push of cold air into the region behind a cold front and strengthening low pressures system. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JLB LONG TERM...Ritzman AVIATION...Rolfson MARINE...JLB
Area Forecast Discussion
National Weather Service Nashville TN
910 PM CST Mon Nov 5 2018 .UPDATE... FOR EVENING DISCUSSION. && .DISCUSSION... Updated suite of forecast products to mention Tornado Watch Number 423 thru 06/09Z (3 AM CST) in zone forecast product. Latest HRRR model depicting best squall line movement west to east across mid state region and adjusted hrly grids with wx and pops accordingly. Highlighted mention of damaging winds, tornadoes, and heavy rainfall with this squall line as it moves across the mid state region. Nashville Metro area continues to look like it will be influenced by this squall line event between 10 PM CST and 1 AM CST. Tweaked hrly temp, dewpoint, and wind speed/direction grids. Current temps trends in line with forecasted lows. Remainder of forecast continues to be on track. .AVIATION... 00Z TAF DISCUSSION. CKV/BNA/MQY/CSV...Went very close to 18Z TAF discussion reasoning. Several amendments probable at all terminal sites due to actual fluctuations in wx, wind, vsbys, and ceilings thru at least 06/10Z. Reason behind this is that there is no way with forecast wx resolution to do these very short term time period deviations accurately in a concise terminal forecast format. One significant change of note though is the introduction of LLWS with 60kts of shear within 2 KFT of sfc. Preliminary data from 06/00Z OHX sounding sounding profile depicting 50-60kts winds as close as 200 feet off sfc. Significant caution is urged for any aviation interest across the mid state region thru 06/10Z. Latest models continuing to support designated TEMPO group impacts and timing windows of potential strong/svr tstms of a potential squall line feature moving across terminal locations. During these TEMPO time periods sfc gusts 40 to 50 kts if not locally higher are certainly not out of the question. Sly sustained sfc winds 10-15kts with gusts to 25kts will veer to the west as sfc cold front moves into northwest portions of mid state by 06/04Z and proceeds southeastward across and out of mid state by 06/12Z. Conditions should rapidly improve to VFR/SKC conditions all terminals 06/14Z-06/24Z as sfc high pressure influences and a dry quasi swly flow pattern becomes established across mid state region. && .OHX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ DISCUSSION......31 AVIATION........31
Area Forecast Discussion
National Weather Service Pocatello ID
551 PM MST Mon Nov 5 2018 .SHORT TERM...Tonight through Wednesday. A quick update early this evening to account for the band of showers extending from Taber into the ERN mountains. The HRRR and to a lesser extent the UofA WRF both show persistent shower activity over the mountains east of Blackfoot and Idaho Falls through the evening with perhaps 1 to 3 inches of accumulation at the higher elevations. See the previous discussion below for more information. Huston Isolated to scattered showers beginning to blossom through the area near the Montana Divide. These will continue through the evening, fueled by steepening low-level lapse rates. Persistent northwest flow and continual moisture stream will keep showers in the forecast through Wednesday, particularly from near Challis through Island Park and stretching southward towards Bear Lake. Terrain enhancement is expected with incremental snow accumulation expected above 4000 - 5000ft. By late Wednesday, accumulations to near half a foot is expected for near Pine Creek Pass and Targhee Pass near Island Park. The long duration of the snow accumulation precludes any need for Winter headlines. Gusty west-southwest winds today will dissipate tonight and into Tuesday as the pressure gradient begins to slacken. Daily high temperatures will hold steady below averages through at least Wednesday as the northwest flow maintains its grip on our area. TAX .LONG TERM...Wednesday night through Monday. This persistent northwest flow pattern persists into the early part of the weekend. We should dry out actually for Thursday and Friday. By late Friday and Saturday, the models still want to drop another storm across the Divide and potentially farther southwest across the state. The ensembles and Blend of Models keep light precipitation (mainly snow) going across the central mountains and eastern highlands very much like we`ve seen for the past several days. The GFS has been consistently farther southwest across the Divide, while the ECMWF has been more consistent with it just brushing the Divide. We still are leaning with the Blend of Model guidance, although limited the snow chances across eastern highlands south of the Big Holes and Palisades through Saturday. The models have been struggling even more for Sunday and Monday, flip flopping between northwest flow on the east side of the ridge or it still moving directly overhead. The Blend of Models actually seems to have suddenly flipped to the wetter scenario, which seemed to be heavily based off the European. We actually went the other way and kept it dry across the region. Precipitation amounts on a daily basis will remain light unless there is a heavier shower or burst of snow. Winds aren`t expected to be too strong, so any impacts related to wind will be minimal at best. Temperatures remain below average for this time of year. Keyes && .AVIATION...Northwest flow continues across eastern Idaho. We will see occasional showers in similar places as we`ve seen in recent days, favoring the eastern highlands and central mountains from around Galena to Gilmore Summits. In terms of VCSH or actual -SHSN, the only airports we see affected are KDIJ and KIDA. If a shower happens to impact an airport directly, there could brief drops in visibility/ceilings to MVFR or IFR and gusty winds. Otherwise, expect VFR at this sites and all of the other TAF locations as well. More widespread stronger winds will persist until sunset before dying off rather quickly. Keyes && .PIH WATCHES/WARNINGS/ADVISORIES...None. && $$
Area Forecast Discussion
National Weather Service Raleigh NC
945 PM EST Mon Nov 5 2018 .SYNOPSIS... An in-situ cold air damming high will extend across the central and western Carolinas and VA through early Tuesday. A warm front will briefly retreat northwestward into portions of central NC midday through mid-afternoon Tuesday, ahead of a pair of cold fronts that will cross the region late Tuesday afternoon and evening. Weak, Pacific high pressure will follow for Wednesday. && .NEAR TERM /THROUGH TONIGHT/... As of 945 PM Monday... A southerly flow a few thousand feet above the surface will strengthen overnight as a well defined s/w and attendant sfc cold front approach from the TN Valley. This sly flow will continue to pump a warm moist air mass over the relatively cool stable air mass near the surface, resulting in extensive low clouds along with patchy drizzle/light rain and areas of fog. Potential for the fog to become dense, especially over the Piedmont and adjacent sections of the Sandhills overnight into early Tuesday. Latest HRRR suggest the dense fog becoming prevalent after midnight. If HRRR trend verifies, will likely need to go with an advisory after midnight. The extensive cloud cover and a slow erosion CAD air mass in place will lead to temperatures holding steady or slowly rising through the overnight. By daybreak Tuesday, most locations should see temperatures in the 60-65 degree range. If the rain coverage is greater than anticipated overnight, this may actually "cleanse" the atmosphere, temporarily reducing the threat for dense fog. && .SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/... As of 314 PM Monday... The main player in our weather for Tuesday will be the approach and passage of the cold front that is currently moving across the Plains. As mentioned in the near-term, increasing S/SW flow ahead of this front will mean gradual warming, but being that the CAD is always slow and tough to erode, the best low level destabilization is expected to occur across the eastern half of our CWA during the daytime prior to the front. Most CAMs suggest a classic pre-frontal band of showers and tstms will sweep across central NC from west to east...first across the Triad and our western zones around mid-day, the central Piedmont, Sandhills and the Triangle during the afternoon, and finally across the I-95 corridor during the early evening. In terms of severe potential, as mentioned, the best instability will be across the eastern half of our CWA, but deep layer bulk shear will be more than adequate (> 40kts) across our entire CWA. Also noted that even where the CAD erodes and low level warming occurs, forecast soundings depict several modest but apparent inversions above the BL. Nevertheless, given the recent rains and wet soils, event modest wind gusts assoc with any decent convection that gets going...can result in a couple...perhaps even several...downed trees across our CWA...with again the best chance for severe convection across the eastern half of our CWA where it will be the warmest. Subsidence, drying, and CAA will commence in the wake of the cold fropa Tuesday evening and night, with clear skies by sunrise Wednesday. Temp forecasts are always a challenge during the CAD erosion timeframe, but attm is appears that readings may climb to around 70 across the Triad, to around 80 across our SE zones. Lows Tuesday night from the mid 40s NW to mid 50s SE. && .LONG TERM /WEDNESDAY THROUGH SUNDAY NIGHT/... As of 235 PM Monday... Wednesday through Thursday: There`s quite a bit going on in the extended forecast period. Expect the stalled cold front along the Carolina coast on Wednesday to slowly retreat northwestward through Thursday. Aloft, a very broad northern stream trough will extend the width of the CONUS, amplifying over the Northern Rockies and High Plains on Thursday. Perturbations along the surface boundary may enhance some of the rainfall expected over the Carolinas. However, the westward extend will depend on the location of the front. The northwestern portions of the area will remain wedged in. The location of the front and the wedge airmass will also impact temperatures across the area. For now, expect highs within a category of normal on Wednesday, upper 60s NW to mid 70s SE. Lows may still be a bit above normal Wednesday night, upper 40s to mid 50s. As would be expected Thursday temperatures will be lower than Wednesday, highs in the low to mid 60s and lows in the mid 40s to low 50s. Thursday night through Saturday: The upper level trough will continue to amplify over the Midwest on Thursday and Friday, with a front strengthening over the Gulf and Southeast. The front should move through the Appalachians and into central NC Friday or Friday night, eroding the weak wedge across the west and resulting in another round of showers across the area. Best chances for showers will come during the day and evening Friday, though will likely start Thursday night over western NC and linger into Saturday morning across the far east. As for temperatures, with little time to warm in the NW, highs on Friday may only get into the mid 50s, while farther to the southeast highs may approach 70 degrees. Lows will be impacted by the timing of the front, but largely expect upper 30s NW to mid 40s SE. Highs Saturday will likely top out in the 50s. Saturday night through Sunday night: Expect west to southwesterly flow aloft as the trough axis broadens again, extending from New England to TX. The surface high dives southward from Canada to the ARKLATEX region through Saturday before building eastward. There is uncertainty how efficiently it will cross the Appalachians, thus adding to the uncertainty in the temperatures and weather for the remainder of the weekend. For now, expect highs similar to Saturday, however lows in the 30s are expected both nights across the area, with some below freezing lows in the NW possible. Wind chills may also be an issue, but will depend on the position of the high. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 715 PM Monday... Mainly IFR ceilings in cntl NC this evening, aside from lingering MVFR ones near and especially southeast of FAY, will lower into LIFR range --with areas of drizzle and dense fog-- overnight, amidst a well-entrenched (in-situ) cold air damming air mass. The southeastern edge of the aforementioned cold air damming regime will be marked by a warm (wedge) front; and this front will retreat nwwd into cntl NC and cause low ceilings and fog to slowly lift and disperse from southeast to northwest, with a following breezy swly wind. That front, and those more-markedly improving conditions to VFR, are most likely to affect FAY and RWI, and least likely to affect Piedmont sites, prior to the passage of a band of showers and storms and related sub-VFR conditions and strong wind gusts. As such, Piedmont sites, particularly INT and GSO, are likely to remain sub-VFR throughout the 00Z TAF period, with only a brief improvement to VFR possible at RDU. Outlook: VFR conditions will follow area-wide, as high pressure builds in behind the front later Tuesday night-Wednesday, though patchy fog and/or low stratus cannot be entirely ruled out around daybreak Thu, particularly at FAY. The nwwd retreat of that same frontal zone will cause sub-VFR conditions and showers to return to srn NC, including perhaps as far north as FAY, Wed night, then otherwise and elsewhere Thu night and Fri. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...MWS NEAR TERM...WSS SHORT LONG TERM...KC AVIATION...MWS