Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/09/19

Area Forecast Discussion
National Weather Service Denver/Boulder CO
855 PM MST Fri Mar 8 2019 .UPDATE... Issued at 827 PM MST Fri Mar 8 2019 Overall the forecast appears to be on track for this evening. We made some minor adjustments to the pops based off the radar this evening. Most of the precipitation so far has fallen as rainfall but should start to see it mix or change over the snow is it continues to track east. The main line of precipitation is fairly progressive, and is moving across the Denver area at this time. Could see a brief period of moderate rain showers, with a mix of snow. There could be enough to produce a quick of inch of snow or slush is it passes by. Not much lightning generated by this except along the WY/CO border earlier this evening. Still a chance over the next hour or so. This is the main band for the plains this evening, anything after that should be light and brief. Gusty downslope winds will develop in the foothills overnight. No changes to the current highlights in effect for the mountains and foothills. Westerly winds will gradually increase across the northeast plains tonight into Saturday morning, then strongest from around 10 am to 4 pm Saturday. && .SHORT TERM...(This evening through Saturday) Issued at 224 PM MST Fri Mar 8 2019 Very active weather pattern over the next 12 hours. Water vapor satellite imagery showing a short wave trough spinning over Utah. This trough will track east across Colorado tonight. Lift ahead of this trough will continue to produce widespread snow across the mountains of Colorado. In addition to this, the airmass is unstable with surface based CAPE off the RAP up to 400 J/kg. Because of the lift and instability, showers and a few thunderstorms will likely produce areas of heavy snowfall. Snowfall rates will top 2 inches an hour for a short time under to strongest convection. Mountain roads will become snowpacked and slippery by sunset. Convection then rolls off the foothills after 00Z. The airmass should be warm enough for mainly rain. However, under the stronger convection, snow and ice pellets will be possible. If this occurs, expect accumulation to be less than an inch. Over the far northeast corner of Colorado, ahead of the convection, drizzle will be possible. Temperatures should be warm enough that it would not be freezing drizzle. Strongest mountain stable layer occurs 12Z to 18Z Saturday. This combined with subsidence behind the exiting system and strong flow aloft will result in very windy conditions for the higher mountains and Front Range Foothills. Will upgrade the High Wind Watch to a Warning. Will need a decent mountain wave to form to help accelerate winds down the foothills. Models show a mountain wave forming late tonight and Saturday morning. Will it be enough to help winds reach 75mph? Tough call, so confidence on Warning is on the low side. Windy conditions will prevail across northeast Colorado as well Saturday. Right now, appears gust to 50 mph will be possible, so no High Wind Warning at this time. There will be enough moisture embedded in the strong flow aloft to produce orographic snow showers over the mountains late tonight and Saturday. Additional snowfall will be light for the mountains Saturday. Most locations will see little if any snowfall, orographic favored areas may see up to 2 inches of snow. .LONG TERM...(Saturday night through Friday) Issued at 224 PM MST Fri Mar 8 2019 For Saturday night, the winds will be diminishing across the far northeast plains as the storm system rapidly shifts into the upper Midwest. There will areas of continued light snow in the mountains, but amounts will be minimal. For Sunday and Sunday night, a more tranquil day across Colorado as high pressure ridge builds into the state. The flow aloft will be shifting back more southwest in response to the next Pacific system which will be digging down into Baja by early next week. There will still be some snow showers in the mountains, but moisture trajectories look to keep most of the showers over northwest Colorado, including portions of Jackson county and lesser snow chances further south along the I70 corridor. The plains will be dry and mild on Sunday but should see an influx of low level moisture Sunday night into Monday morning. A developing Denver cyclone may also result in low clouds and fog moving into the Denver area as well. Deeper subtropical moisture riding along a jet streak will also be advecting into the region during the day on Monday in advance of the strong upper low over Baja. Expect scattered showers to develop across the plains, especially southern sections over the Palmer Divide and Lincoln county. The main question through the middle of next week is the track of the Baja low as it moves northeast through Wednesday. There is a bit better continuity in model track again today with the low moving into southeast Colorado late Tuesday and early Wednesday before moving it into eastern Nebraska by late Wednesday. The European/Canadian solutions show this the most, while the GFS track is still a bit further east and south. With this overall track, there is a threat of heavy snow somewhere over eastern Colorado early next week especially if European/Canadian verifies. For Thursday and Friday, there will still be a fair amount of troughiness over the region for a continued chance of snow showers over the mountains. The plains will generally be dry for later in the week. && .AVIATION...(For the 06Z TAFS through 06Z Saturday night) Issued at 827 PM MST Fri Mar 8 2019 Main band of showers moving across the terminals at this time. Rain or a rain/snow mix will produce MVFR cigs and vsby restrictions through 05z then a steady improvement thereafter. Heavier showers activity could produce ice pellets and/or snow. If any accumulations were to occur they will be light. Gusty west/northwest winds to 25-30 kts also possible. That will decrease as well for from around 05-08z. VFR the rest of the period. On Saturday, partly cloudy to mostly sunny skies will prevail Saturday. Gusty northwest winds to 30 knots will be possible after 15Z. && .BOU WATCHES/WARNINGS/ADVISORIES... High Wind Warning from midnight tonight to noon MST Saturday for COZ035-036. Winter Storm Warning until 6 AM MST Saturday for COZ031-033-034. && $$ UPDATE...Cooper SHORT TERM...Meier LONG TERM...Entrekin AVIATION...Cooper
Area Forecast Discussion...Updated
National Weather Service Billings MT
900 PM MST Fri Mar 8 2019 .UPDATE... Satellite and radar continue to show the shortwave tracking through northeast Wyoming and southeast Montana. The RAP continues to have the heaviest snowfall across mainly Powder River and Carter counties, in the warning area. Webcams show a similar trend. The highlight look in good shape. Reimer && .SHORT TERM...valid for Sat and Sun... Current satellite imagery shows a shortwave lifting thru the great basin in SW flow aloft, and a weak cut off low over the PacNW. Diffluence aloft is increasing in response to the energy to our south, and latest mid level analyses show backing winds. Precip is moving into northern WY as upslope flow continues to deepen. We have seen areas of light snow today, mainly in our west from Livingston to Judith Gap and in the east close to the Dakotas border, but the main event is beginning this evening. Have made no changes to our current winter highlights. Strongest ascent will clip far southeast MT, and this is where the heaviest snow will fall (warnings are in effect for Powder River and Carter counties). Forecast amounts of 5-9 inches are in line with consensus model QPF fields, and the Garcia method of using mixing ratios on an isentropic surface. So there is some confidence here. That being said, latest HRRR and RAP runs have shifted the 700mb low a bit further to the NW, which shifts the axis of heavier snow a bit further into our cwa, to include eastern Sheridan to Fallon counties. Have adjusted amounts up slightly to accommodate a slight shift. Places like Broadus, Ekalaka and Alzada will see a good dose of snow tonight thru Saturday morning. Places like Sheridan, Lame Deer and Baker will see a good snowfall but in the 3-6 inch range. Further west, the ascent is much weaker but will linger due to weak but slow-moving low to our west. A few inches of snow are possible along our western foothills. As for Billings, we are largely between the two areas of forcing and will see less accumulation. It will snow some here in the city, but have lowered forecast amounts to 1-2 inches. Even less snow (under an inch if any) will fall along the Musselshell River. We will dry out by Saturday afternoon and early evening as the shortwave shifts east. We will see a split NW flow and dry conditions Saturday night through Sunday night. Temperatures will remain below normal with highs ranging from the mid 20s to mid 30s the next two days, coldest in our east. JKL .LONG TERM...valid for Mon...Tue...Wed...Thu...Fri... The forecast area will be between systems Monday into Tuesday. A split flow aloft will be over the forecast area along with some weak ridging and subsidence. This will result in dry conditions and mild temperatures prevailing. Monday and Tuesday will see the warmest temperatures of the week with middle 30s to lower 40s common, which continues to be below normal. The next chance for snow will be arriving Wednesday and Thursday as another upper low will move out of the four corners region. This will, along with an associated surface low, intensify and move into the central plains region. Models differ in the strength of the upper low but do agree on keeping the heaviest of the precipitation east of our forecast area across Nebraska and South Dakota. However, at the same time, another surface low will move southeast across Idaho with general troughiness over the Northern Rockies. This will result in temperatures cooling back into the 20s and 30s along with a good chance of snow. Timing is still too far out for details so monitor the forecast as we go through this weekend into early next week. Hooley && .AVIATION... Snow will continue with IFR conditions overnight over southeast MT and north central WY. Over south central MT, MVFR conditions with snow will improve later tonight to VFR. Mountains will be obscured. Winds will be gusty in the KSHR area. RMS && .PRELIMINARY POINT TEMP/POPS... Sat Sun Mon Tue Wed Thu Fri ----------------------------------------------------------- BIL 020/031 010/033 014/038 020/041 020/035 021/032 013/031 85/S 00/U 00/U 01/U 23/S 31/E 00/U LVM 015/027 005/030 008/036 015/037 016/029 014/027 008/029 96/S 00/U 00/U 02/S 33/S 21/B 10/B HDN 017/031 004/032 006/037 013/040 015/034 019/032 008/030 95/S 00/U 00/U 01/U 24/S 31/E 10/B MLS 018/025 004/027 006/033 013/036 016/031 020/029 009/026 96/S 00/U 00/U 00/B 13/S 32/S 10/B 4BQ 019/029 006/031 007/038 017/040 017/033 019/030 011/029 +8/S 10/B 00/U 01/B 14/S 53/S 10/B BHK 018/025 006/026 006/033 017/036 018/029 019/027 010/024 +9/S 10/B 00/U 01/B 13/S 63/S 10/B SHR 018/030 007/033 010/039 018/043 020/034 019/030 011/030 97/S 00/U 00/U 01/B 24/S 42/S 11/B && .BYZ WATCHES/WARNINGS/ADVISORIES... MT...Winter Weather Advisory in effect until 11 AM MST Saturday FOR ZONES 30>33-35-38-57-58. Winter Weather Advisory in effect until 5 PM MST Saturday FOR ZONES 34-39>41-56-64>66. Winter Storm Warning in effect until 5 PM MST Saturday FOR ZONES 36-37. WY...Winter Weather Advisory in effect until 11 AM MST Saturday FOR ZONE 99. Winter Weather Advisory in effect until 5 PM MST Saturday FOR ZONE 98. && $$
Area Forecast Discussion
National Weather Service Columbia SC
1014 PM EST Fri Mar 8 2019 .SYNOPSIS... A frontal boundary over the northern Midlands will slowly sink southward into Saturday resulting in showers. As a strong low pressure system develops in the upper Midwest over the weekend, a cold front will approach the Carolinas and Georgia. Scattered showers and a few thunderstorms are expected ahead of the front by late Sunday. The front may stall near the area into early next week. A wide range of temperatures will occur Saturday as weak wedge conditions develop in the South Carolina Piedmont north of the front. Above normal temperatures are expected late in the weekend ahead of the next cold front. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... An east-west oriented front will extend through the central or south part of the forecast area tonight. There will be a series of mid-level shortwave troughs in the flat flow. The models indicate continued isentropic lift supporting rain. The rain should be mainly in the north section where deeper moisture has overspread the area. Radar trends support a considerable gradient in pops from north to south. Trends support mainly light rainfall amounts of one quarter of an inch or less late tonight. The RAP keeps negative showalter index values west of the forecast area overnight. The trend has been for lightning to dissipate as it moves eastward and toward the forecast area from north-central Georgia. We forecasted just isolated thunderstorms in the west part overnight. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Saturday...Frontal boundary remains across the area in the morning then will lift slowly north. In-situ wedge across the north Midlands most of the day will keep temperatures down a bit. Weak isentropic lift possibly increasing across the north Midlands should result in a few scattered showers mainly in the morning. There appears to be a shortwave trough moving through the area in the afternoon and with diurnal heating there may be some lingering showers although the front appears to be north of the area. Upper-level ridging and drier air should limit showers in the afternoon as the front moves north of the area. Moisture may be a limiting factor but precipitable water near 1.25 inches. Will continue slight chance pops across the western Midlands late Saturday afternoon into evening. Blended temperature guidance appears on track with above normal temperatures over much of the region as warm front moves slowly north. Tricky temperatures forecast north Midlands where in-situ wedge may be slow to erode. Sunday...little change from previous forecast. A deep mature cyclone will lift northeastward from the Central Plains into the Great Lakes region Saturday night and then into eastern Canada Sunday pushing a cold front into the forecast area by the evening. There are some ingredient in place for convection but severe weather threat appears limited as the greatest moisture flux and wind shear shift through the area Sunday morning and out of the region by the time the axis of highest precipitable water values and instability arrive with the front late in the afternoon. Most of the upper dynamics will be well north of the forecast area as well leaving the frontal boundary as the primary forcing element. Will continue to carry high chance to low likely pops with the highest pops in the southeastern portion of the forecast area during the evening hours. QPF across the north Midlands appears to be more limited with 12z guidance. Temperatures well above normal Sunday afternoon ahead of the front...approaching 80 degrees in the southeast Midlands/CSRA. && .LONG TERM /MONDAY THROUGH FRIDAY/... Frontal boundary appears to be well south of the area Monday resulting in a dry forecast through at least midweek as surface and highly amplified upper ridge builds over the eastern CONUS. Another deep low moves into the central Plains Wednesday. Upper ridge axis moves east of the area Thursday which will allow some shortwave troughs to move into the area. Moisture may be increasing ahead of an approaching cold front late in the week. Temperatures during this period will be near to above normal. Temps should be in the 70s to near 80 Friday ahead of the front. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Shallow surface frontal boundary stalled NE-SW from KFLO-KXNO- KDNL. Wedge conditions developing over the Upstate and Piedmont to the north. Radar and satellite support 2 upper troughs with deeper moisture and shower sinking ESE through Central SC right now and another upstream in N GA. Both of these will develop showers and tempo MVFR conditions within the TAF period, with heaviest precipitation expected at KCAE/KCUB. Difficult cig/vis forecast as front is expected to wave slightly north and south in response to each trough approach/passage with deepest moisture and solid IFR conditions north of the front. Used a combination of LAMP and HRRR model guidance to indicate moderate confidence in MVFR conditions with showers and IFR conditions at KCAE/KCUB after second trough passage...with improvement after 17-21Z tomorrow as front returns north as a warm front. MVFR expected at AGS/DNL/OGB as the front remains just overhead or slightly to the north...with earlier improvement after 18Z. EXTENDED AVIATION OUTLOOK... Flight restrictions again possibly returning Saturday night into Sunday. Showers and isolated strong thunderstorms possible Sunday afternoon/evening with another cold front. High pressure builds in slowly Monday through Wednesday with no expected restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion
National Weather Service Wilmington NC
940 PM EST Fri Mar 8 2019 .SYNOPSIS... A weak cold front will drop south and stall over the area overnight before returning north as a warm front by Sunday. A cold front will cross the region late Sunday, possibly accompanied by thunderstorms. Dry weather then returns under high pressure early next week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 930 PM Friday...Rain has continued to spread farther south than any model thought possible this evening. Surface observations show rain has reached the ground as far south as Kingstree, Marion, and Myrtle Beach. High radar reflectivity values in the Lumberton area earlier were partially the result of bright-banding as the radar beam encountered the freezing/ melting level only 6000 feet aloft. Although I`m still not excited about any model`s initialization of the current frontal position or rainfall distribution, the 01z RAP isn`t bad and correctly paints rain farther south than any other model guidance. It shows our area entering a relative lull in rainfall rates and coverage now through about midnight, followed by a second wave of more concentrated rain north of Kingstree, Conway, and Myrtle Beach early Saturday morning. This second wave should then begin to diminish before daybreak Saturday leaving cloudy skies in its wake. Changes with this update centered on adjusting the frontal position southward now and through the night to match observations of NE winds in the Myrtle Beach/Marion/Florence area, and the aforementioned PoP/Wx adjustments. Discussion from 630 PM follows... A solid area of rain extends from Burgaw westward across Elizabethtown, Lumberton, and Bennettsville, then farther west across Charlotte and into upstate South Carolina. This appears to be associated with isentropic lift centered near the 300K theta surface, approximately 9000 feet AGL. The majority of models don`t show the lift quite far enough south to account for the current positioning of echoes on radar, so I`ve had to manually adjust the forecast slightly to introduce better rain chances across our northern South Carolina counties and into the Wilmington area for this evening. Hourly temperatures have been adjusted to reflect a large area of 60+ degree readings lingering for most areas south of the east-west front extending from just north of Florence, Whiteville and Wilmington. Overall synoptic thinking for overnight has changed little with the progression of this front as it is expected to slowly sink farther south across South Carolina. Discussion from 300 PM follows... Latest radar imagery showed a line of rain showers moving into the forecast area just to the west of the I-95 corridor during the early afternoon ahead of a weak front that is pushing into the southeast portions of the CONUS. Temperatures across the region ranged from 64 near Whiteville to 57 near Maxton, with other temperatures in the upper 50s and lower 60s. Models prog the approaching cold front to push through the region staring this afternoon and early evening past the I-95 corridor on a line from Burgaw to Florence, and eventually pushing to North Carolina coastal locations by late this evening and overnight. South Carolina coastal locations are not anticipated to receive very much in the way of new precipitation tonight. Front will stall across the area Saturday, but latest projections are fairly quiet as to expected precipitation. Some scattered rain showers will be lingering mainly in North Carolina along the stalled boundary, but Saturday afternoon should be dry with mostly cloudy skies. High temperatures will vary Saturday due to orientation of the frontal boundary, ranging from the upper 50s in North Carolina to the low 70s for inland South Carolina. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 300 PM Friday...Initially south to southwest flow at low levels and a deep westerly flow aloft will exist, with moisture mainly confined below 10 ft and some upper level moisture through much of Sunday. Therefore, expect some clouds around on Sunday, but the best moisture and pcp chances will come heading in the eve. Pcp water will reach 1.5 inches just ahead of the cold front, and best mid to upper level support comes together late Sun eve as shortwave pushes cold front through the area. Overall, does not look like atmosphere will be conducive for severe weather, but an isolated damaging wind gust is possible. Expect very warm temps on Sun, reaching well into the 70s with lows in the 50s Sun night. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 300 PM Friday...High pressure will build in behind cold front through Mon but some lingering moisture will remain in the mid to upper levels through Mon as ridge to the south holds it up a bit. Expect seasonable weather through mid week with plenty of sunshine for the most part, as ridge builds up from the south and high pressure migrates across the northeast. As ridge becomes more amplified up the Southeast coast through mid week, some high clouds may spill over the ridge into the area, so can not rule out clouds at times, but this will also help to warm up the air mass, especially Thurs into Fri as WAA occurs with southerly return flow as high pressure shifts off the coast and farther east. Chance of rain will increase heading into Fri and the weekend as cold front approaches from the west. Warm temps on Mon will get knocked back down toward climo Tues and Wed and the warm again Thurs into Fri. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 00Z...VFR ceilings as a stalled frontal boundary begins to move to the south overnight. Showers will develop and move west to east along the boundary throughout the period. By morning, a stratus event is likely as the front stalls to the south of the Myrtles and a high pressure system to the NE brings IFR conditions to all terminals. High confidence in IFR at the inland terminals, but coastal terminals may see the influence of the warm ocean water, possible lifting IFR to MVFR or VFR. Shower chances will continue throughout the day on Saturday, but decrease after morning. Toward the end of the period, the front will get a push from the south and this should provide clearing from south to north across the area with VFR returning ahead of a cold front on Sunday. Extended Outlook...Possible MVFR/IFR from clouds and showers associated with a frontal boundary in the area Sunday into Mon. VFR Tues & Wed. && .MARINE... As of 930 PM Friday...The front has slid south the coast to Myrtle Beach where northeast winds are now being reported. The front shouldn`t move significantly farther south, and I actually expect winds to maintain a southerly component in the Winyah Bay/Georgetown area overnight. Seas have begun to build by 0.5 to 1.0 feet over the past several hours due to swell arriving from a large area of stronger winds well offshore. Discussion from 630 PM follows... Winds and seas remain benign this evening as a weak front slowly settles south toward Cape Fear. This should eventually make it down to the Grand Strand area late tonight. Southerly winds will shift north to northeasterly as the front passes by, with speeds generally 10 kt or less. Buoy- reported waves are currently only 1.5 to 2.5 feet across the area, but should build by about a foot overnight due to stronger winds developing well offshore. Discussion from 300 PM follows... Main concern is the possibility of marine fog offshore Saturday afternoon into Saturday night. Quiet conditions offshore with waves between 2 and 4 feet through Saturday night. Mainly onshore winds up to 10 kts can be expected as a frontal boundary approaches, but does not quite cross the offshore waters. An occasional gust to 15 mph could occur tonight and Saturday afternoon. Winds will increase out of the S-SW through Sunday, ahead of an approaching cold front. WNA model continues to keep winds and seas just below SCA thresholds, but will be close. Northerly flow will develop early Mon as high pressure builds in behind cold front and will pick up slightly in NE push on Tues. The high will migrate eastward but remain north of the waters through mid week with an on shore flow developing on Wed before winds come around to the S by Thurs. Seas up to 4 to 5 ft Sun evening will trend downward on Mon. Should see only a slight bump up in seas on Tues and again on Wed in on shore flow, but overall expect seas in the 2 to 4 ft range between Mon aftn and Thurs. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...None. MARINE...None. && $$ SYNOPSIS...MCK NEAR TERM...TRA/MCK SHORT TERM...RGZ LONG TERM...RGZ AVIATION...21
National Weather Service Wilmington OH
958 PM EST Fri Mar 8 2019 .SYNOPSIS... Mostly cloudy conditions are expected tonight behind a wave of low pressure. Showers and possibly thunderstorms will accompany strong low pressure Saturday and Saturday night, along with windy conditions lasting through Sunday behind a cold front. High pressure is forecast to provide dry weather Monday and Tuesday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... A sharp line has been drawn across the ILN CWA tonight with regards to cloud cover, with stratus remaining in place across the southern half, and skies becoming basically clear across the northern half. A quicker erosion of this cloud deck has slowed over the past few hours, but looking at GOES-E nighttime microphysics RGB imagery, it does still appear that a slow erosion is ongoing. Thus, some continued expansion of the clearing is expected over the next several hours, before clouds likely begin to expand again closer to morning. At some point, high clouds will also begin to spill over the forecast area. The most difficult part of the forecast tonight is with regards to fog, as the clearing does present the possibility that some fog could develop in the northern half of the forecast area. While SREF probabilities have continued to indicate this possibility, LAMP guidance and HRRR visibility projections have not been as robust with fog development. In addition, winds are expected to begin a gradual increase after 06Z. For this reason, fog was kept out of the grids -- though some MVFR-type restrictions to visibility might still be possible. Where the clearing has developed, temperatures are falling at a quicker rate than previously forecast, so some reductions were made to the min temp grids in the northern half of the forecast area. Looking into tomorrow, the overall thinking regarding the forecast has not changed too much tonight. Some adjustments were made to the grids to delay the onset of precipitation, which looks like it will not be enveloping the Cincinnati area until about 18Z. Previous discussion > Wave of low pressure producing light precip is moving east. This is leaving the ILN area in a weak easterly flow in the circulation around high pressure centered over the Eastern Great Lakes. Little mixing during the evening and early in the overnight hours should allow clouds to persist under a low level inversion, and patchy fog may form. Later tonight, winds and mixing will begin to increase in the tightening pressure gradient ahead of a warm front developing in front of deepening low pressure. This should allow fog to dissipate, and clouds should show a decreasing trend, especially across northern counties farther from the warm front. Cloud cover will help temperatures remain much higher than in recent nights, with lows forecast to range from the upper 20s north up to the mid 30s south. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/... Deep low pressure will be traveling across Iowa on Saturday, before crossing Lake Michigan Saturday night. There will be very strong moisture transport and lift on a 70 knot 850 mb jet ahead the low, and a warm front will provide added convergence that will enhance shower development. Also may observe some thunderstorms forming in elevated instability. With showers overspreading the area Saturday and continuing into Saturday night, around an inch of rain falling on wet soils may lead to isolated high water issues. Another problem will be strong winds resulting from the tight pressure gradient around the low. South winds could gust to 30 knots by Saturday evening, with gusts in the low 30s possible Saturday night as winds shift to a more westerly direction in the vicinity of a cold front trailing the low. For the first time in several days, temperatures will rise above normal in most locations due to warm advection on the southerly flow, with highs ranging from the mid 40s north to the mid and upper 50s south. && .LONG TERM /SUNDAY THROUGH FRIDAY/... For Sunday into Sunday night. low pressure and mid level energy will continue to move away to the northeast into Canada. It will remain breezy to windy with the highest wind gusts approaching 40 to 45 mph in the northwest zones with 25 to 35 mph elsewhere. Winds should diminish Sunday night as the pressure gradient relaxes and the mixing depth shrinks with diurnal cooling. Skies will range from partly cloudy south to mostly cloudy north in a glancing blow of CAA. Highs on Sunday will range from the lower 40s northwest to the upper 50s southeast. Lows Sunday night will range from the upper 20s northwest to the mid 30s southeast. High pressure will build south into the region Monday into Monday night, and then it will push east of the area on Tuesday. Mostly sunny skies are expected Monday and Tuesday with mainly clear skies Monday night. Temperatures will average a little bit below normal. A highly amplified upper level flow pattern is forecast to develop across the CONUS mid to late next week. A mid level ridge will eventually be replaced by a shearing mid level trough. This pattern will be slow to develop and move through the region due to its amplification, and as such a, cold front doesn`t push through the area until Thursday night/Friday. The chances of showers will increase through the period. The first likelihood will be Wednesday night into Thursday in a zone of strong, moist ascent associated with a LLJ. Another chance will increase once again Thursday night into Friday morning with the passage of the cold front. Temperatures will warm into the 60s by Thursday ahead of the front, then drop back down into the 40s and 50s in the wake of the front on Friday. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Precipitation has ended across the area for the night, but some persisting MVFR/IFR ceilings remain in place, especially at the KCVG/KLUK/KILN airports. Some brief MVFR ceilings may be possible at KDAY/KCMH/KLCK as well. These clouds should break up to some degree tonight, allowing for some periods of VFR ceilings even at the Cincinnati airports. However, there is also a chance of some MVFR fog development as well, particularly from about 06Z-13Z. On Saturday, winds will shift to the southeast and begin to pick up in intensity, with some gusts to around 20 knots possible by 18Z. Clouds will gradually thicken, with the greatest chance for MVFR ceilings during the morning once again at the Cincinnati airports. Chances for showers and embedded thunderstorms will increase at the end of the TAF period, especially heading into Saturday evening. LLWS is also expected during the evening. OUTLOOK...MVFR/IFR conditions are expected with rain and thunderstorms on Saturday night, along with gusty winds. MVFR conditions are possible on Sunday, along with gusty winds. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Coniglio NEAR TERM...Coniglio/Hatzos SHORT TERM...Coniglio LONG TERM...Hickman AVIATION...Hatzos
Area Forecast Discussion
National Weather Service Key West FL
907 PM EST Fri Mar 8 2019 .DISCUSSION...In the middle and upper levels(700-200 mb), latest available satellite imagery overlaid with model streamline analysis depict the axis of a developing full latitudinal negatively tilted trough across the Western CONUS with axis from the Bitteroots SSW to Southern New Mexico. Conversely and downstream of that the axis of a ridge is oriented from the Western Gulf of Mexico northwards to Western Ontario. South Florida and the Keys are beneath the eastern periphery if the approaching ridge axis. At the surface and in the lower to mid levels(Surface to 700 mb), latest available marine and land surface observations and analysis detail the center of a 1030 mb surface anticyclone parked over the Western Atlantic near 35N 70W. South Florida and the Keys lie beneath the southwestern periphery of the ridging. The 00Z evening sounding illustrated just gentle to moderate mostly east winds just off the surface to about 825 mb, with a 2 degree C inversion from about 835 to 810 mb, and the column was still dry with PWAT only at .98 inches. .CURRENTLY...As of 800 pm, skies are mostly clear across the Keys Island Chain and surrounding waters. Radar does detect a weak band of light showers moving slowly northwest towards the Ocean Reef and Southeastern Dade County, with false returns elsewhere. Temperatures across the islands are in the middle 70s with dewpoints in the middle 60s. C-man stations along the Florida Reef are recording east winds between 10 and 15 knots, with islands sensors mainly east near 10 mph. .SHORT TERM...Overnight, latest available forecast soundings indicate that PWAT should remain near one inch overnight. Surface ridging should remain in place from near 35N 70W southwest to South Georgia. Since a few showers are presently in close proximity to the Upper Keys, and the latest HRRR hints a few showers could move over the Middle Keys towards daybreak, will maintain a dime pop overnight, but any of these will be very brief and sparse. Low temperatures should only fall into the lower 70s as winds should remain mostly east. The ongoing forecast is on track so no changes on this cycle. && .MARINE...Overnight, Gentle to moderate breezes are expected overnight, with now headlines or advisories anticipated. Winds near 15 knots will be found out in the Florida Straits and 10 to 15 knots elsewhere. && .AVIATION...VFR conditions expected at both the KEYW and KMTH island terminals. Winds will be from around 100 degrees aoa 8-10 knots with a few gusts. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...None. && $$ Public/Marine/Fire...Futterman Aviation/Nowcasts....Futterman Upper Air/Data Collection......SD Visit us on the web at Follow us on Facebook and Twitter at:
Updated for 00Z Aviation Forecast Discussion below.

&& .PREV DISCUSSION... /issued 334 PM CST Fri Mar 8 2019/ DISCUSSION... A warm front remains draped across the Mid-South this afternoon. The front currently stretches from Forrest City to Decaturville. North of the front, temperatures are in the mid 40s to mid 50s with patchy showers and areas of fog. South of the front, temperatures are in the upper 50s to upper 60s with patchy showers. The front is forecast to shift slightly to the south by 00Z. This will turn Memphis and the rest of the West Tennessee winds to the northeast. The front will begin lifting back to the north after midnight. Patchy showers will continue to be possible across the CWA. In addition, fog will continue to occur north of the front. The fog may become dense and a Dense Fog Advisory may become necessary as Little Rock is already sitting at 1/8th of a mile as it sits just north of the front. This may happen at more sites after sunset. After midnight, the warm front will begin lifting to the north as a potent upper trof digs into the Southern Plains. Several CAM models show thunderstorms blossoming along the warm front just before 12Z. These thunderstorms will be elevated in nature but will be capable of producing large hail. Threat area will be for locations along and north of Interstate 40. As the warm front surges north by 15Z. A second round of thunderstorm activity will begin to push in from the west ahead of a pre-frontal trof. This activity will quickly push east into Middle Tennessee by midday as a third round of thunderstorm activity will develop along the cold front. This activity will push across the CWA during the late afternoon into the early afternoon hours. This third round of activity is the one of most concern as it will occur with the best instability. There have been concerns that the potent shortwave would lift off to the northeast before this convection would develop. The latest 18Z NAM shows that the shortwave will be passing through the region just as these thunderstorms will be developing. The Enhanced Risk has been pushed to the north to align with the stronger forcing for ascent than the previous DAY 2 issued early this morning. Greatest area of concern for severe thunderstorms with the possibility of tornadoes will be across Northeast Arkansas, the Missouri Bootheel into Northwest Tennessee. South of this area, there remains questions on how far removed from the forcing will the thunderstorms still be able to become severe. The 12Z NSSL WRF and 12Z HRRR show a vigorous line tracking across North Mississippi while other CAM models show limited development south of Interstate 40. Thus a lot of questions remain about tomorrow and a lot it just comes down to timing of the shortwave. Stay tuned for forecasts updates with the latest information. Besides the threat for severe thunderstorms, gusty southerly winds will occur across the Mid-South by mid-morning. A Wind Advisory may be needed across much of the Mid-South. High pressure will build into the region Sunday into early next week. A few upper level disturbances will move through the zonal flow producing small light rain chances across North Mississippi and East Central Arkansas at times. After a warm day on Saturday, temperatures will return with highs in the 50s for much of the area. Another potent upper trof will approach the Mid-South by Wednesday. The ECMWF continues to be much slower with the progression of the associated cold front than the GFS and Canadian. This would result in quite a bit of rain falling over the Mid-South during the Wednesday Night through Thursday Night time frame. This would increase the risk for flooding with an already saturated ground. Severe weather chances with this system look limited at this time as the SFC low will occlude as the front pushes into the area and will pinch off the instability. Stay tuned. KRM && .AVIATION... 00Z TAFs 23Z surface analysis showed a stationary front just south of MEM, near OLV, with modified marine air immediately south. Short range guidance from RAP, HRRR, NAM-3km depict this surface front dropping slightly south through the MEM inbound push this evening, then pushing quickly north by 10Z or so. IFR will be likely to the north of the front. TS chances continue this evening and overnight, but likelihood too low for mention. TS chances increase after 12Z from the west, with the approach of pre-frontal surface trof and stronger support aloft. Will likely see a lull in TS activity once this pre-frontal trof lifts east, and winds veer to the southwest late morning / early afternoon. During this lull, low level jet will be strong, varying from 50 to as much as 70 KTs late morning through midafternoon. The LAV MOS guidance MVFR CIGs may be a little too pessimistic during this period. As mentioned in the public discussion, there are questions related to TS coverage with the late afternoon/early evening cold frontal passage. Best TS chances appear for TUP Saturday evening, after the valid TAF period. PWB && .MEG WATCHES/WARNINGS/ADVISORIES... AR...None. MO...None. MS...None. TN...None. && $$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
533 PM CST Fri Mar 8 2019 .UPDATE...For 00Z Aviation discussion below && .SHORT TERM...(This evening through Saturday night) Issued at 315 PM CST Fri Mar 8 2019 The previous forecast remains on track. The only change was to try to tighten up the snowfall gradient on the southern edge of the heavy snowfall area. As of now it appears that snowfall gradient will extend from just west of Mankato through the Twin Cities. This gradient will wash out north and east of the Twin Cities as temperatures cool overnight and the snow becomes more widespread. Given the uncertainty, decided to keep the Winter Storm Watch going since there could be significant sleet accumulation, plus the precip will fall with winds of 20 to 25 mph. Tried to use the forecast soundings off the HRRR to get an idea of where the warm nose would persist, and where it would wetbulb down below freezing. Generally speaking areas west of the Lower Minnesota River Valley will have mainly snow, but areas to the east will have a wintry mix cut down on the overall snowfall totals. This ends up putting the northwest part of the Twin Cities in the 8-10" snowfall range, with the southeast part in the 4-6" range. A subtle change of 1 or 2 degrees will make all the difference, so could easily see this forecast changing over the next 24 hours. The upper level wave driving this system will take on a negative tilt, so that should enhance the forcing and lead to some impressive snowfall rates of 1 to perhaps 2 inches per hour. East wind of 20 to 25 mph will lead to drifting snow, so with the full snowbanks could see drifts of 2 or 3 feet very common across the Winter Storm Warned area. In the wake of this storm winds will continue in western and southern Minnesota, so the Winter Storm Warning will continue through Sunday morning. Do not expect blizzard conditions since the cold air advection is not overly strong, and the surface low remains fairly steady with minimum pressure around 988 mb. The precip will end across western MN on Sunday, and winds will decrease. .LONG TERM...(Sunday through Friday) Issued at 330 PM CST Fri Mar 8 2019 Headlines will gradually end over the CWA during the day Sunday as the snow ends and winds subside in the wake of the storm. Highs pressure and quieter conditions will remain Monday and Monday night with below normal temperatures. The next strong storm system is forecast to rotate through the southwest CONUS trough and lift into the Colorado/Oklahoma panhandle region by Wednesday morning. Long term deterministic models are more in line with the more western track the previous 12z GFS model run indicated yesterday. With this track, the surface low will lift north/northeast toward central MN by Thursday morning. Deeper moisture is expected to lift north ahead of the storm, with integrated water vapor transport(IVT) standardized anomalies of 3 to 4 standard deviations above normal moving into southern MN Wednesday. Precipitable water values of 2 to 3 standard deviations above normal are forecast for the same time period. This would bring at least 0.75 inch PW`s with the 12z GFS indicating at least 1 inch. The heaviest precipitation is expected to occur later Tuesday night through Wednesday evening as the main low lifts across MN. QPF should range rather high with the event, with 1 to 2 inches likely across much of the MN portion of the CWA. We could see a rain/snow mix develop into Tuesday night as the surface low approaches, with much of the precipitation expected to fall as rain Wednesday. Some isolated thunder will also be possible, especially over the southeast as the low moves across Minnesota. The best LI`s trend slightly negative over the southeast as a pocket of mid level lapse rates of around 7-7.5 C/km moves into south central MN Wednesday afternoon. This will no doubt generate some localized flooding, especially in urban areas where storm drains remain snow covered or frozen. Also, small streams will likely see water rises over the ice. It will overall begin to ripen the snow pack along with air temperatures rising to the lower 40s across the easter CWA. The system lifts through Thursday with precipitation ending Thursday night. Temperatures are expected to trend back below normal again for Friday. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 534 PM CST Fri Mar 8 2019 The primary change in the TAFs was to introduce more of a wintry mix at central/southern sites. KAXN and KSTC should see primarily snow as the precipitation type, but KRWF/KMKT/KMSP/KRNH/KEAU will most likely see a mix until late Saturday afternoon. That could include a period of freezing drizzle at event onset for some, but surface temperatures look to warm above freezing between 18Z and 20Z. By 00Z Sunday, snow should be falling area-wide, with the heaviest at northern/western sites (KSTC/AXN/KRWF, and KMKT on the eastern edge of the heavy snow axis). East/southeast winds will become gusty on Saturday. KMSP... Main change was to include a longer duration of a wintry mix, with the transition to all snow not expected to occur until 22Z Sat. When the precip starts around the noon hour, surface temps should be above freezing, so do not expect freezing rain/drizzle at this time. Sleet will however be a possibility until the transition to snow occurs around 22Z. LIFR conditions are possible during the evening. /OUTLOOK FOR KMSP/ Sun...MVFR/IFR with -SN early. Then, MVFR. Wind NW 15-20G25 kts. Mon...VFR. Wind WNW 10 kts. Tue...VFR. Wind SE 10-15 kts. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...Winter Storm Warning from noon CST Saturday to 7 AM CDT Sunday for WIZ014-023>026. Winter Storm Warning from 3 PM CST Saturday to 10 AM CDT Sunday for WIZ015-016-027-028. MN...Winter Storm Warning from 9 AM CST Saturday to 1 PM CDT Sunday for MNZ041-042-048-049-057>059-066>069-076-077. Winter Storm Warning from noon CST Saturday to 7 AM CDT Sunday for MNZ043>045-050>053-060>063-070-078. Winter Storm Warning from 6 AM CST Saturday to 1 PM CDT Sunday for MNZ047-054>056-064-065-073>075-082-083. Winter Storm Watch from Saturday morning through Sunday afternoon for MNZ084-085-091>093. && $$ SHORT TERM...JRB LONG TERM...DWE AVIATION...LS
Area Forecast Discussion
National Weather Service Marquette MI
636 PM EST Fri Mar 8 2019 .SHORT TERM...(This evening through Saturday) Issued at 314 PM EST FRI MAR 8 2019 Earlier this morning an upper level trough passed over Southern California and has since reached the Rockies. This is also evident through the general upper-level troughing across the western portions of the CONUS with slight ridging through the Central Plains this afternoon. Light WAA and 290K-295K isentropic lift can be seen on both the GFS and RAP this afternoon through tonight in west and southern portions of Upper Michigan. This slight lift has led a broad area of higher clouds for the UP and will have the additional chance to produce a few flurries this evening. Accumulations, if any, will be light as moisture is lacking through the DGZ with saturation staying at 3kft or less. Increasing clouds tonight will provide warmer lows tonight than the last few nights. Clouds out east will be delayed and temperatures have been lowered accordingly. For Saturday, clouds will continue to build throughout the area as a broad area of WAA and isentropic lift continue ahead of the surface low that will impact us Saturday night into Sunday morning. .LONG TERM...(Saturday night through Friday) Issued at 319 PM EST FRI MAR 8 2019 Still looking at two systems for our area Saturday night into Sunday then again Wednesday and Thursday. Weekend system will produce moderate accumulations of wet/heavy snow along with gusty winds and patchy blowing snow on Sunday. Second system looks warmer with mainly rain expected. Upper level trough over the southwest CONUS moves to the central Plains by Saturday afternoon with sfc low deepening to around 990mb near Kansas City. Negative tilted upper trough and associated 988 mb sfc low is expected to lift into the Upper Great Lakes Saturday night with sfc low staying around 988mb reaching northern Lk Michigan by daybreak Sunday. Overall the general idea of this system remains consistent; marginal QPF amounts for a warning snow event, lower SLRs/wetter snow and gusty nw winds on Sunday as the system exits the area. Trends are farther east with sfc low track, so other than some drizzle/freezing drizzle late Saturday night over the southeast/east forecast area, looks like ptype for all areas remains snow. Majority of steadier/accumulating snow does not arrive until late Saturday evening, even over the south and WI border zones. Will keep the SPS going and let mid shift see if any areas will need a warning. Otherwise, they can put advisory out for most if not all of western and central Upper Michigan for the expected wet and heavy snow. Behind the system Sunday night and Monday, nw winds will result in light lake effect downstream of any openings in the ice cover on Lk Superior. Deep moisture and H85 temps are marginal leaving only shallow moist layer with sub 5kft inversion height. High pressure ridge Monday night through Tuesday night will keep weather dry. Temps on Tuesday may reach well into the 30s, if not even over 40F as long as mid clouds hold off til later in the day or at night. Next system arrives late Tuesday night through Wednesday with primary surge of precipitation lifting through on Thursday. Upper level system gets deflected north as it grinds into strong upper ridge over eastern North America. Sfc low tracks farther west than this weekend system, so looks like a warmer system for sure with rain the main ptype until colder air works back in later Thursday or Thursday night. 12z GFS was a lot wetter with this system with over an inch of qpf encroaching on western Upper Michigan. GEFS probabilities hint at higher qpf over far west Upper Michigan as well and on to the west over Lk Superior. Previous runs of the GFS were more toned down though, as are the current forecasts of the ECMWF and GEM-NH. Temps should rise into the upper 30s or lower 40s on Wednesday, only fall into the lower 30s on Wednesday night and push back into the 40s on Thursday before cooler air moves in from the west late Thursday or Thursday night as upper low and sfc low head east as bulk of jet energy surges ahead of the trough making it more progressive. Even though it is a short duration warm up, could see at least some limited responses from melting snow. Forecast dwpnts reach lower 40s over the south but stay in the 30s elsewhere. The higher dwpnts will help the melting process and could also result in better chances of advection fog as the higher dwpnts flow across the melting snowpack. Both of these issues will have to be addressed as we get closer to this system. Please note that our office has started issuing our routine spring hydrologic outlooks (ESFMQT) with complete details on current and expected snowpack and weather conditions, especially in regard to flooding potential. && .AVIATION...(For the 00Z TAFS through 00Z Saturday evening) Issued at 634 PM EST FRI MAR 8 2019 VFR conditions are expected through the TAF period at KCMX and KSAW. Expect VFR conditions at IWD to slowly become MVFR late tonight/Saturday morning as lower upstream ceilings move into the area. It is possible that IWD will go between VFR and MVFR through the period. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 314 PM EST FRI MAR 8 2019 Winds over Lake Superior will approach 30 knots on Saturday night and and then expect low-end gales Sunday afternoon. Winds will drop below 20 knots Monday night until Wednesday as winds will approach 30 knots again. Expect gusts over Lake Superior in the 20 to 30 knot range through the rest of the forecast period. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... None. Lake Superior... None. Lake Michigan... None. && $$ SHORT TERM...JAW LONG TERM...JLA AVIATION...Voss MARINE...JAW
Area Forecast Discussion
National Weather Service San Francisco Bay Area
411 PM PST Fri Mar 8 2019 .SYNOPSIS...Light shower activity across the Monterey Bay will taper off through the afternoon and evening. A different storm system will bring another shot of beneficial rain tomorrow with lingering showers into tomorrow night. Dry high pressure returns Monday with another chance of light rain by Tuesday as another fast moving system passes through. && of 01:45 PM PST Friday...A weak disturbance passing through California has helped to excite a broad unstable airmass in place across the state and the nearby coastal waters. Visible satellite imagery depicts scattered cumulus clouds developing in this unstable air mass while KMUX radar shows light to moderate returns under the deeper convective cells. Radar returns have generally been below the threshold that would signify hail while convective cloudtops are at a relatively shallow 5000-10000 feet. That said, convective shower activity has been slightly more robust and widespread than models suggested, with isolated showers as far north as the Golden Gate into the early afternoon. The bulk of the shower activity has been focused across the Monterey Bay and Big Sur regions, where generally 0.05-0.20" of rain has fallen since midnight. Showers will likely continue across the Monterey Bay region through the afternoon before finally tapering off later this evening. Temperatures began the day 3 to 10 degrees cooler than the previous morning given the cooler air mass and pockets of mostly clear skies, but are now running in line with yesterdays mid 50s readings. These temperatures are roughly 8 to 12 degrees below normal readings for early March. Temperatures tonight are expected to be slightly cooler than last night, particularly for the inland portions of the region though overnight lows may be limited by increased cloud covering from an approaching storm system set to arrive Saturday morning. Short term forecast models generally agree that a storm system currently 600 miles west of Point Mendocino will begin to spread another round of precipitation across the region prior to sunrise Saturday morning. Lighter warm sector precipitation should give way to occasionally moderate frontal precipitation shortly after sunrise for the North Bay before shifting southward and inland through the day. The local WRF and HRRR suggest that the frontal precipitation will shift south of the Golden Gate by the late morning before spreading deeper southward and inland by the early afternoon. Lighter post frontal showers will then persist through the remainder of the day before mostly tapering off overnight Saturday into Sunday. A few weak isolated showers could persist into Sunday, but most locations should remain dry given the limited coverage and intensity. Storm total rain from this system should be highest across the North Bay, particularly the coastal range, where up to 1.50 to 2.00" are possible The North Bay valleys could see around 0.75 - 1.00" while locations farther southward and inland will see progressively less, such as around 0.50" near San Francisco and Oakland and 0.25-0.33" near San Jose and Monterey. Southerly winds will become breezy to occasionally gusty through Saturday morning but are expected to remain below wind advisory criteria throughout the storm system. A muted warming and drying trend is forecast to occur on Monday under weak high pressure aloft. This is trend ends abruptly as a different storm system is set to impact the area on Tuesday. Models agree this system will be weaker than previous storm systems and move at a quick clip. Light rain accumulations are expected through the day Tuesday, but may be enough to be a nuisance for any outdoor events and rush hour commutes. Dry conditions return for the tail end of the week from Wednesday through Friday though models hint at another weak wet system impacting the area next weekend. && of 4:00 PM PST Friday...Quiet afternoon with mainly scattered cumulus clouds. VFR expected tonight. The next system will spread lower cigs into the Bay Area after 12Z with a short period of steady light rain Saturday afternoon. Northwest winds this evening switching to the southeast late tonight. Southeast winds gusting to 20 kt Saturday morning. Vicinity of KSFO...VFR through tonight. Northwest winds gusting to 25 kt through 04Z. Increasing clouds with cigs 3500-4500 ft Saturday morning. VCSH possible after 12Z with more widespread coverage of light rain late Saturday morning through Saturday afternoon. Southeast winds increasing to 15-20 kt late Saturday morning. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR with scattered clouds tonight. Increasing clouds after 12Z with light rain in the afternoon. Northwest winds 5 to 10 knots becoming SE overnight. && of 03:39 PM PST Friday...While wind speeds have diminished this afternoon, winds will being to increase late tonight into Saturday morning in advance of an approaching storm system. This system will result in gusty winds into Saturday along with a chance of rain showers. Another system will arrive on Tuesday with stronger northwest winds and rain showers. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Arena to Pigeon Pt 10-60 nm from 9 PM SCA...SF Bay from 3 AM SCA...Pt Arena to Pt Reyes 0-10 nm from 3 AM SCA...Pt Reyes to Pigeon Pt 0-10 nm from 3 AM SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm from 3 AM && $$ PUBLIC FORECAST: DRP AVIATION: W Pi MARINE: RGass Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Raleigh NC
937 PM EST Fri Mar 8 2019 .SYNOPSIS... A stationary front will linger across South Carolina and Georgia through Saturday night. A surge of warm and moist air aloft will produce areas of light precipitation over North Carolina through tonight. The stationary front to the south will lift north as a warm front late Saturday and Sunday, before a cold front crosses the area Sunday night. Dry weather will return under high pressure early next week. && .NEAR TERM /THROUGH TONIGHT/... As of 935 PM Friday... Evening update: Intensity of the rainfall has decreased over the past couple of hours as a wave moved south and east of the area. Still expecting light rain or drizzle south of 64 but areas to the north have seen an end to the rain at this point. SREF and HRRR visibility fields are targeting the Triad for potential areas of fog overnight. So far visibilities have dropped but only to MVFR levels. CAMs also suggesting another weak wave moving through the southern counties between 6 and 9z. Lowered low temperatures a bit across the north as have already reached the upper 30s. Expect mid 30s across the north to low 40s south. Previous discussion follows. -Ellis Widespread light rain is currently crossing S and E portions of the forecast area at a much faster pace than CAM runs from just a few hours ago depicted. Only the RAP appears to be catching up to reality, although it, too, is a couple of hours too slow. Nevertheless, the precip has been mostly light, a trace to a couple of hundredths of an inch, owing to the still-fairly-high cloud bases and continued dry low levels. The leading subtle perturbation helping to drive this current rainfall will exit to our east shortly, creating a relative lull with only patchy light rain for an hour or two. But additional rain now over TN associated with another mid level perturbation is poised to overspread NC starting late this afternoon, and high rain chances should continue well into tonight, with the greatest coverage across southern NC where low level moist upglide will be strongest and deepest, through the 285-295K layer, near the low level frontal zone sitting across SC. Mid-upper levels will dry a bit across NW and far N sections later tonight, so expect a trend toward lighter and more patchy rain and areas of drizzle there overnight, while higher pops for mostly rain persist across the south. Thick overcast skies will dominate, with areas of fog developing, particularly across far N and NW sections, within deeply stable air. Lows are expected to range from the upper 30s N to mid 40s S. -GIH && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... As of 340 PM Friday... The stable pool will remain locked in over central NC through much of Sat, albeit with rising cloud bases, with high pressure centered over W Quebec nosing southward. The W-to-E frontal zone will hold just to our S into the afternoon, but is expected to edge northward into the SE CWA late in the day. 850 mb winds from the SW will increase through the day, strongest over the W, as a potent shortwave trough over the central CONUS lifts NE into the Great Lakes Sat/Sat night. Moist upglide will persist, deepest over the SW CWA, although the downstream ridge axis shifting over the Carolinas and subsequent drying aloft (above minus 5C) will limit precip amounts especially over NE sections to patchy rain/drizzle. The shortwave trough itself will track well to our NW but the increasing mid level flow over the NW CWA will re-moisten the mid levels there late Sat into Sat night, and pops in the NW Piedmont will be trended back up to good chances, with lower pops in the E and SE closer to the offshore-drifting mid level ridge axis. Expect highs Sat to be in the mid 40s NW ranging to upper 50s-near 60 in the SE. Will maintain chance pops Sat night, higher NW and lower SE, with temps rising as the warm front advances to the N and NW. The stable air mass is likely to hold over the NW Piedmont, however, and temps there should rise just into the upper 40s to near 50, while the remainder of the forecast area gets well into the 50s. -GIH && .LONG TERM /SUNDAY THROUGH FRIDAY/... As of 255 PM Friday... The main wx story for Sunday and Sunday night will be the passage of a cold front, progged to move across our CWA during the late day, into the evening hours. In advance of this front, several bands of showers will move across our area, but we noted that QPF values have been trending down with recent model runs, thanks in part to the bulk of the upper energy lifting by well to our north. In any event, look for QPF ranging from about 1/4 to 1/2 inch, highest east of I-95. The front and assoc moisture is then progged to move well to our south by mid-day Monday, with a clearing sky trend to follow. With a sfc and mid level ridge building over the region, look for fair weather through at least mid-day Thursday, before the risk for rain increases again late-week assoc with the next cold front approaching and progged to move through on Friday. Given the slower movement of that front and prolonged pre-frontal moisture advection, rain amounts with that front should be heavier than the rain with Sunday`s front. Temps next week will run above normal most of the week, with Tuesday night into Wednesday being the coolest period, thanks to northerly low level flow associated with high pressure building in from the north. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... As of 730 PM Friday... An area of light to moderate rain is currently moving across central NC, producing sub-VFR conditions. The bulk of the rain will exit to the east, though lingering rain and/or drizzle will persist into Saturday, especially across the Piedmont. This will lead to lowering cigs and visbys this evening and tonight as a CAD airmass becomes locked in across the area. Cigs may briefly improve some across the far eastern and southern TAF sites on Saturday, though likely to remain below a thousand feet as the main surface cold front remains to the south of the area. Outlook: Sub-VFR conditions will continue through the remainder of Sat night with patchy drizzle and light rain, most prevalent at INT/GSO. Strengthening low level winds, atop the cold stable surface airmass, from the SW Sat night may allows for a risk of LLWS at 2000 ft AGL as winds increase to 40-45 kts (at 2k ft). Warm weather is expected Sun but with likely MVFR conditions and brief showers with a passing cold front. An isolated storm is possible near FAY late Sun. VFR conditions are likely to return for Mon/Tue/Wed as the front settles to our S and high pressure builds in. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Blaes NEAR TERM...Ellis/Hartfield SHORT TERM...Hartfield LONG AVIATION...BSD/Hartfield
Area Forecast Discussion
National Weather Service Tulsa OK
941 PM CST Fri Mar 8 2019 .DISCUSSION... Forecast was updated to insert patchy dense fog mention and issue a dense fog advisory for Carroll and Madison counties in AR thru 6 AM. Cool and moist conditions north of the warm front across northern AR has allowed dense fog to develop. A check of observations around the area does suggest it is patchy though. The latest HRRR suggests that the best fog potential will stay over north central AR and south central MO tonight. Lacy && .PREV DISCUSSION... /Issued 752 PM CST Fri Mar 8 2019/ UPDATE... Some minor tweaks were made to the forecast tonight. See discussion below. DISCUSSION... The forecast remains on track for the most part. The warm front, which will play a role in the severe potential late tonight into Saturday morning, is, in a sense, pivoting at this hour. The western portion of the front, currently aligned from NE-SW into northern TX, is beginning to lift north in response to the deepening surface low over eastern CO. The eastern portion of the front is remaining quasi-stationary over southern AR. By late tonight, the warm front may gain a NW-SE orientation as the western portion of the front is drawn north toward the surface low. The theme of the forecast remains the same. Storms will develop late tonight, likely elevated to start, across NE OK. Other storms will get going over south central OK ahead of the Pacific front closer to 12Z and will progress across southeast OK and into western AR thru early Saturday morning. Storms along and south of the warm front will pose a limited tornado threat, with large hail to 2 inches in diameter the main threat. Damaging winds are a threat as well, even north of the front where a shallow stable layer near the surface will exist. The tornado probabilities on the DSP (Decision Support Page) were tweaked to show the expected orientation of the warm front tonight. Overnight low temp forecast was adjusted as well with some sites already below the forecast, though they should be near their mins now with a steady or slow rise in temps after midnight. Lacy PREV DISCUSSION... /Issued 552 PM CST Fri Mar 8 2019/ AVIATION... CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG. MVFR ceilings are expected to spread back over the CWA this evening and overnight tonight ahead of an approaching dryline and cold front. Thunderstorm are forecast to develop late tonight across Eastern Oklahoma and move into Northwest Arkansas early Saturday morning ahead of the dryline. IFR conditions and gusty winds will be possible within the convection. Continued with tempo groups for timing. Behind the convection...VFR conditions with gusty southwest winds becoming gusty to strong westerly winds and mostly clear conditions from west to east during the mid morning to early afternoon hours Saturday. PREV DISCUSSION... /Issued 256 PM CST Fri Mar 8 2019/ DISCUSSION... Severe weather likely overnight with the potential for very large hail, including at least a limited tornado threat along and south of I-40. This afternoon, frontal boundary was located over far southeast Oklahoma near a Wilburton, Poteau line. South of the boundary, temperatures have warmed into the lower 70s. Strong upper storm system currently located over southern NV will shift east tonight, becoming negatively tilted as upper trough axis lifts into the central Plains by Saturday morning. In response, multiple clusters of strong to severe thunderstorms are expected to develop by 09Z with storms rapidly spreading through all of eastern Oklahoma by 12Z and across the remainder of northwest Arkansas by 15Z. Elevated instability in excess of 2000 J/KG in a few areas, coupled with strong deep layer shear around 60-70 knots will support embedded supercells with the potential for very large hail up to the size of tennis balls given the cold temperatures aloft/steep lapse rates. In addition, warm front is forecast to lift near or just south of I-40 by this time, which could provide an enhanced severe threat with damaging winds and a few brief tornadoes possible. Thunderstorms will likely shift east of the region by mid morning Saturday with the severe weather threat ending. Still expect strong/gusty west winds to develop behind departing system with gusts to 35-40 mph across far northeast Oklahoma. Although widespread precipitation is expected, fine fuels will rapidly dry out Saturday afternoon as temperatures warm into the upper 60s to lower 70s with RH values in the 25-35 percent range. Active weather pattern will continue into the early to middle part of next week as another strong/highly amplified upper trough moves out the desert southwest into the southern/central Plains. Shower/thunderstorm chances will increase by Tuesday as stronger isentropic lift develops north of frontal boundary ahead of main storm system. Models in better agreement concerning timing of main convective line Tuesday night into Wednesday morning with heavy rainfall possible. Although surface based instability is expected to be marginal, very strong low level wind fields suggest at least a limited severe threat in addition to the heavy rainfall potential. && .PRELIMINARY POINT TEMPS/POPS... TUL 50 71 35 54 / 90 50 0 0 FSM 54 74 41 60 / 90 80 0 0 MLC 54 74 40 53 / 90 50 0 10 BVO 48 67 30 53 / 90 50 0 0 FYV 49 68 34 53 / 90 90 0 0 BYV 42 68 36 54 / 90 90 0 0 MKO 51 69 38 53 / 90 60 0 10 MIO 47 67 34 52 / 90 80 0 0 F10 49 71 38 52 / 90 50 0 10 HHW 63 74 42 58 / 80 60 10 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...Dense Fog Advisory until 6 AM CST Saturday for ARZ002-011. && $$ LONG TERM....30