Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/11/19

Area Forecast Discussion
National Weather Service Columbia SC
1025 PM EDT Sun Mar 10 2019 .SYNOPSIS... A weak cold front will move through the region tonight, with scattered showers and a few thunderstorms expected ahead of it. The front will stall south of the area into early next week. && .NEAR TERM /UNTIL 6 AM MONDAY MORNING/... Radar and satellite imagery show extensive clouds over the area along with a few light showers in the southeastern Midlands and southern CSRA. Overnight a weak boundary will remain just south of the area with a weak disturbance moving through the eastern Midlands. Although the instability will be weak overnight there is some potential for a few showers and possibly a thunderstorm in the eastern Midlands. Toward daybreak the chance of showers will end with clouds beginning to slowly diminish. Overnight lows will range from the upper 40s north to the upper 50s south. && .SHORT TERM /6 AM MONDAY MORNING THROUGH WEDNESDAY/... Surface high pressure builds into the Southeast U.S. through midweek. It will be a tranquil weather pattern with near normal temperatures for mid March. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... High pressure moves off the East Coast on Thursday which allows moisture and warmer temperatures to move back into the region. An occluded surface low pressure system tracks into the Great Lakes Thursday Night into Friday with a trailing cold front slowly pushing into the Midlands and CSRA on Friday. Forecast models do not depict significant instability with this frontal passage, therefore will not mention thunderstorms in the forecast. High pressure rebuilds into the Southeast U.S. for next weekend with dry conditions and near to slightly below normal temperatures. && .AVIATION /02Z MONDAY THROUGH FRIDAY/... Observation trends support mainly VFR conditions. Low-level drying has occurred in a westerly flow. The cold front will move through the area tonight but radar trends indicate showers will likely remain south of the area closer to deeper moisture. The front will be just south of the area Monday. Satellite trends indicate continued mid-level cloudiness will continue. Diminished net radiational cooling because of this cloudiness plus some boundary layer wind should help prevent fog during the early morning hours. The GFS and NAM MOS plus HRRR and most SREF members maintain VFR conditions through the 24-hour TAF period. The GFS and NAM MOS support light west wind veering to northeast as indicated by the GFS and NAM MOS. EXTENDED AVIATION OUTLOOK...Dry high pressure is forecast to dominate through Wednesday. A frontal system may bring flight restrictions Thursday and Friday. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$ SYNOPSIS...99 NEAR TERM...99 SHORT TERM...99 LONG TERM...99 AVIATION...99
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
714 PM CDT Sun Mar 10 2019 .DISCUSSION... Updated for the 00Z Aviation Discussion. && .AVIATION... Conditions expected to deteriorate through the evening, especially across the coastal region, with IFR/LIFR conditions developing between 00Z-06Z. LRD should take a big longer to lower with lowering CIGs a bit more closer toward 06Z and beyond. Improvements to VSBYs/CIGs expected around 15Z, however MVFR CIGs will likely last through the rest of the TAF period. The exception is LRD which may be able to break to VFR after 18Z. Winds will generally be out of the E-SE 5-10 KTs. && .PREV DISCUSSION... /Issued 322 PM CDT Sun Mar 10 2019/ SHORT TERM (Tonight through Monday Night)... As of writing light showers/drizzle is ongoing across the Coastal Plains and Victoria Crossroads as low level moisture increases underneath the cap. A quasi-stationary boundary is currently draped across central Texas and is progged to slowly track to the south throughout the night. Ahead of this feature, fog is expected to develop across much of the area as dewpoint depressions will near 1 degree with condensation pressure deficits ranging from 3 to 5 mb. We are currently seeing brief improvements in visibilities along the coast but expected sea fog to return this evening. As the aforementioned shortwave moves to from NW to NE across the northern part of the state late tonight, the weak boundary will move south. How far south is the question. The NAM brings the boundary into our northern tier of counties, while the RAP keeps it across the Hill Country. Low level moisture will continue to increase across the region, with the highest moisture axis located along the Rio Grande. This boundary should be the focus for scattered showers and potentially an isolated thunderstorm or two on Monday. Our best chances for precip will be out west but continued WAA across the Coastal Bend and Victoria Crossroads will lead to sustained chances of scattered showers. Onshore flow will keep us fairly warm over the next few nights with lows 10-15 degrees above normal for this time of year. High temps are expected to be a few degrees below normal tomorrow across the east as mostly cloudy skies will hold temps down. We may see some breaks in the clouds across the Brush Country tomorrow, so they will warm into the low 80s. LONG TERM (Tuesday through Saturday)... The mid-level closed low that is currently off the coast of northern California will finally be coming onshore Tuesday over the Baja/northwestern Mexico area. This will provide a strong southwest flow of Pacific moisture to the mid-levels. A mid-level shortwave looks to pass just north of the area during the day. This coupled with southeasterly onshore flow at the surface, will bring slight chances for precip. While CAPE is extremely meager Tuesday, forecast soundings show great SRH and shear which could bring some rumbles of thunder to the area. By Tuesday night, the low pressure system lifts in the desert southwest and looks to cross the TX Panhandle by late Wednesday morning. This will push a Pacific cold front through the area. With the added instability from the front, values of CAPE, SRH, and shear values increase, so wouldn`t be surprised if some storms could become strong to an isolated severe. Small hail and gusty winds would be the main threats. PWATs also rise to near the 99th percentile, so any slow moving storms may produce a decent amount of rain. The mid-level low should lift quickly towards the Great Lakes region by Thursday and precip will clear out of the area from west to east. A second stronger cold front will finally push south through the area late Wednesday night/early Thursday morning. The colder air mass behind the front will bring high temps back down into the 60s for the end of the week into the weekend. Northerly surface flow looks to stay in place through the weekend. Long range models have some discrepancies for precip chances for Friday into Saturday with the GFS keeping the area dry vs the ECMWF trying to build moisture over the area and the Gulf. Would think the GFS would be the more correct solution, so have lowered the PoPs given by the blends but retained some PoPs. Marine... We have seen improvements in visibilities along the coast this afternoon, however sea fog will develop again this evening as warm air continues to flow over the cooler shelf waters. Went ahead and extended the Marine Dense Fog Advisory through 7 AM and it will likely need extending after that. A weak to moderate southeast flow will continue to kick off the work week. SCA conditions are expected to develop across the coastal waters Tuesday evening into Wednesday afternoon as a strong upper level system and associated frontal boundary move across the region. A second cold front will move across the waters on Thursday, turning winds to the north, and SCA conditions are likely to develop in its wake, and persist through Friday afternoon. MARINE... && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 68 77 67 77 67 / 20 20 20 20 30 Victoria 66 76 65 76 65 / 30 30 30 30 40 Laredo 69 83 69 85 66 / 30 30 30 20 20 Alice 67 79 67 81 67 / 20 20 20 30 30 Rockport 66 74 66 73 65 / 20 20 20 20 30 Cotulla 65 77 65 81 61 / 30 40 40 30 40 Kingsville 69 79 69 79 68 / 20 20 20 20 30 Navy Corpus 69 75 69 73 67 / 20 20 20 20 30 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...Dense Fog Advisory until 7 AM CDT Monday For the following zones: Bays and Waterways from Baffin Bay to Port Aransas... Bays and Waterways from Port Aransas to Port O`Connor... Coastal waters from Baffin Bay to Port Aransas out 20 NM... Coastal waters from Port Aransas to Matagorda Ship Channel out 20 NM. && $$ CB/85...AVIATION
Area Forecast Discussion
National Weather Service Grand Forks ND
643 PM CDT Sun Mar 10 2019 .UPDATE... Issued at 641 PM CDT Sun Mar 10 2019 Added patchy fog to the forecast for the southwestern half of the CWA as HRRR guidance is picking up on efficient radiational cooling overnight. Otherwise, the forecast remains on track. && .SHORT TERM...(This evening through Monday) Issued at 343 PM CDT Sun Mar 10 2019 This evening, some mid level clouds will linger in the area, especially over portions of northwest MN, as the primary longwave upper trough propagates through the Dakotas and into MN. Expect light winds and temperatures dropping into the single digits above and below zero as surface high pressure builds through the region tonight and early Monday. With Sunday`s sunshine melting the new snow on paved surfaces and temperatures dropping to near saturation levels overnight, can see potential for patchy fog. However, this will not quite be an ideal radiational cooling scenario with the lingering clouds and light winds, so will hold on adding to forecast at this time. Look for warmer air to begin building in Monday as warm air advection develops with southerly flow behind the surface high. .LONG TERM...(Monday night through Sunday) Issued at 343 PM CDT Sun Mar 10 2019 Strong WAA and moisture advection through midweek, with strong storm system possibly bringing myriad of impacts to the Northern Plains Wednesday through Thursday night. Monday night-Tuesday night: WAA results in above freezing/above normal temperatures finally returning to our CWA by Tuesday, with degree warming at surface dependent on clearing. This is complicated by the influx of moisture within southerly flow and potential for melting to add low level moisture, which could lead to persistent fog or low stratus. Under ideal conditions potential is there for upper 30s and lower 40s over parts of the southern RRV and northwest MN on these days with overnight lows possibly hovering near or just above freezing. Depth of saturation combined with some weak ascent at times could result in drizzle or freezing drizzle particularly Tuesday-Tuesday night. Wednesday-Thursday night: Strong upper low still projected to move towards the Northern Plains out Colorado, though trend has been towards slowing this down and shifting it a little further south. Consensus of models favors deformation axis extending up into our CWA with current track, with high QPF across our south Wed night into Thursday. Slower timing may favor majority of precip to occur after air mass becomes colder decreasing potential for rain or freezing rain, and increasing potential for heavy snow. In addition, strong wind signal as LLJ on NW side of upper low supports wind gusts 45 to 60 mph over our CWA (strongest on ND side of Red River Valley). Older snow pack will likely be crusted over, however if these strong winds align with snowfall then whiteout conditions would be possible. At this range further track changes would shift impacts away or further into our CWA, and impacts will be highly dependent on track/timing. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 637 PM CDT Sun Mar 10 2019 VFR CIGS prevail west of the Red River this evening with MVFR to upper IFR conditions for KBJI and KTVF. This will deteriorate overnight as efficient radiational cooling and fresh snowfall combine to facilitate low stratus and patchy fog development across the region. West winds will remain under 10 knots through the overnight hours and into Monday morning. Any patchy fog that develops will lift gradually after sunrise. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...None. MN...None. && $$ UPDATE...Lynch SHORT TERM...DJR LONG TERM...BP AVIATION...Lynch
Area Forecast Discussion
National Weather Service Green Bay WI
720 PM CDT Sun Mar 10 2019 Updated aviation portion for 00Z TAF issuance .SHORT TERM...Tonight and Monday Issued at 244 PM CDT Sun Mar 10 2019 The latest RAP analysis and satellite/radar imagery show a potent area of low pressure exiting the region over northeast Ontario early this afternoon. Visibilities continue to improve over northern WI as light snowfall on the back edge of the system diminishes. Back edge of the cloud shield, however, is just starting to enter western WI. Some partial clearing appears possible by late this afternoon, particularly in the downsloping areas of northeast WI, as this cloud line draws closer to the area. With the snow ending, forecast concerns generally revolve around cloud trends and temps. Tonight...Northwest winds will remain breezy tonight between the departing low pressure system off to the east and high pressure over the central Plains. Though the back edge of the cloud mass will pass across the area this evening, models show low level cold advection continuing through the night, with progged soundings indicating a thin saturated layer getting trapped beneath the subsidence inversion. Downsloping over northeast WI could be enough to overcome this shallow layer of strato-cu, and will continue to show mostly clear to partly cloudy skies developing by late evening and overnight. Central and north- central WI may not be as lucky, and will continue to show partly to mostly cloudy skies there. Due to the breezy WNW winds and at least scattered cloud cover, sided with the warmer temp guidance for lows ranging from the mid teens to near 20 by Lake Michigan. Monday...High pressure will continue to draw closer to the region which should lead to a quieter day. Any lingering clouds over central and north-central WI should retreat to the north during the morning. But then with heat of the day, steepening low level lapse rates should lead to scattered cu popping in the afternoon. Temps will fall back slightly with highs ranging from the upper 20s to low 30s across most of the area. .LONG TERM...Monday Night Through Sunday Issued at 244 PM CDT Sun Mar 10 2019 The main concern in the extended portion of the forecast will be the potential rainfall/flooding potential for the middle of the workweek along with above normal temperatures. Monday night through Tuesday: A surface ridge and increasing 500mb heights will be in place through this time period, bringing an extended break in the precipitation along with warmer temperatures. In fact many places will warm to near normal by Tuesday afternoon. Highs Monday will be around 30 while high temps warm to the mid and upper 30s for Tuesday. Overnight lows will be chilly with lows dropping down into the teens Sunday night and to the single digits above and below zero for Monday night. Leaned toward the colder guidance for Monday night with high pressure over the area, clear skies and PWAT values around 25 percent of normal. Wednesday through Thursday: The next southern stream piece of energy is expected to eject out of the Four Corners region into the central Plains Tuesday night into Wednesday morning. This would likely lead to rapid cyclogenesis across the Oklahoma and Texas Panhandles Wednesday morning. The low is then expected to lift northeastward, reaching western or central WI late in the day Thursday. This would keep most of the CWA in the warm sector, keeping the precipitation mainly in the form of rain. There could be a brief period of mixed precipitation early Tuesday evening, but this should quickly transition to all rain for the rest of this time period. Still could cause a brief period of hazardous travel. Of greatest concern will be how much rain falls out of this system as it traverses the area. It looks like there will be plenty of moisture for the system to work with as the surface isobars remain wide open to Gulf moisture through much of this time period. PWAT values are progged to be around 1.0 to 1.5 inches for this time period, which is roughly 200 - 250 percent of normal for this time of year. A strong southerly LLJ is progged to develop ahead of this system, which will allow moisture to quickly advect northward into the CWA along with much warmer temperatures. Actually, most of the models are pushing 850mb temperatures up to around the +6 to +10C range Wednesday into Wednesday night. This would allow temperatures to warm well above freezing through this time period with most locations warming into the upper 40s and even pushing into the low 50s in a few locations. The combination of increasing dewpoint temperatures (above freezing/mid to upper 30s) and warmer temperatures will start melting some of the snow across the area; however, this will take some time as the snowpack is fairly dense and will take time to ripen to the point where rapid melt would take place. The bigger concern will be largely focused on the potential for an inch or so of rain to fall (GEM/GFS) on frozen ground and across areas that may have poor drainage due to ice/snow clogging. The latest 12Z model run of the EC has less QPF, closer to a half inch or so. There will of course be some contribution from melting snow, but the bigger issue will likely be any significant amount of rain that falls, which may lead to at least localized flooding concerns in areas that have poor drainage. The rain will likely come in a couple of waves, the first would be Wednesday into Wednesday night as waa/moisture advecting increase across the area, leading to strong isentropic upglide ahead of an approaching warm front. The warm front is expected to slide into/through the area Wednesday night into Thursday morning, which would be the most likely time for heavier rainfall and fog. A dry slot may end the rainfall for a period during the day Thursday before the upper- level system and surface low slide directly overhead, leading to the next shot of rainfall. Rest of the extended: Another cold front will pass through the area ushering in colder air and a fairly deep upper-level trough for Friday into Saturday. This will effectively put the brakes on any snow melt issues and help to lock in any water making its way through the snowpack. Otherwise, temperatures will fall back below normal with highs only expected to reach into the upper 20s and low 30s for Friday into Saturday. As the colder air filters in, any lingering precipitation, associated with the trough overhead, will likely transition over to some light snow. Only minor snowfall accumulation is expected at this time. && .AVIATION...for 00Z TAF Issuance Issued at 717 PM CDT Sun Mar 10 2019 Low clouds have scoured out of most of the area, with just a combination of sct-bkn low and middle clouds likely to linger across the far north overnight. Winds will remain fairly strong overnight, but some of the gustiness will diminish. Expect some daytime convective cloudiness to develop Monday, but coverage will be limited so primarily VFR conditions are anticipated. && .GRB WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM.....MPC LONG TERM......Cooley AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1047 PM CDT Sun Mar 10 2019 .SHORT TERM...(This evening through Monday night) Issued at 318 PM CDT Sun Mar 10 2019 Early afternoon satellite imagery together with RAP13 surface analysis and 500mb heights showed and upper level shortwave trough along the MN/Dakota border, with another trough upstream across southern Canada. These two features will merge as they are forced eastward by an upper level ridge racing in upstream. The subsidence associated with this ridge will lead to a surface high pressure system building over the Upper Midwest later tonight and tomorrow. This subsidence can already be seen by the clouds dissipating this afternoon over the Dakotas. For that reason expect clear skies, but cooler temperatures to continue tonight and tomorrow. Did increase highs above guidance north of I-94 for tomorrow, since there should be full sun and light winds which usually ends up warming the wooded areas more than the snow-covered areas of western and southern Minnesota. Could see some fog develop as early as Tuesday morning on the leading edge of the cold air advection ahead of the next system. .LONG TERM...(Tuesday through Sunday) Issued at 318 PM CDT Sun Mar 10 2019 Forecast concern remains the midweek system which will bring heavy rain some flooding concerns followed by cooler temperatures, some snow and strong winds Thursday. Southerly winds increase Tuesday as a weak short wave travels to the north of the area. This should draw lower clouds north during the day along with the chance of some light rain mainly in the afternoon. We should see temperatures warm to the 35 to 40 degree range with sunshine becoming less apparent. Models continue trend of developing strong cyclogenesis over the Colorado/Oklahoma panhandle region Wednesday morning and lifting northeast to Iowa by THursday morning. Strong lift moves into the area later Wednesday/Wednesday night as the upper trough approaches and moisture lifts into the area. 12z NAEFS standardized anomalies of PW`s continue the trend of 3 to 4 standard deviations above normal with at least 0.75 to 1 inch PWs affecting the area during this period. This should generate some higher QPF values during this period as the deformation axis moves in. Localized flooding in urban areas and area streams/lowland flooding can be expected if the 1 to 2 inch QPF is realized Wednesday/Wednesday night. Fog will be an issue as well, with higher dewpoints, rain and melting snow. Deterministic model trends continue to lift the surface low to the southeast of of Minnesota Thursday. We will likely see some transition from rain to snow as the upper trough and surface system exit the area. There could be some accumulating snow as temperatures cool rapidly from west to east. into Thursday night. Strong northwest winds will develop with 25 to 30 mph sustained winds anticipated with gusts around 40 mph at least to the west and south if models do verify current trend. Following the storm, we see cooler temperatures and dry continue through the weekend. && .AVIATION...(For the 06Z TAFS through 06Z Monday night) Issued at 1047 PM CDT Sun Mar 10 2019 Only potential issue continues to be threat of fog overnight beneath the surface ridge axis in central MN. The HRRR continues to be pretty aggressive with fog development over NW MN, but is limiting it`s expansion across central MN. Blend of hi-res models continues to show fog developing into AXN tonight, so kept that mention going, though the LAV is trending less and less bullish on the fog there, so it`s certainly possible they see nothing at AXN. Given recent model trends, feeling more confident in keeping fog out at any other locations. Mainly clear skies are expected Monday, though winds will switch to the south as the ridge axis works east. Looks like low clouds really hold off on getting up here until Tuesday morning. KMSP...We will likely see a period of cross winds Monday afternoon, but with speeds under 8 kts, they should be of minimal impact. /OUTLOOK FOR KMSP/ Tue...VFR early, then IFR/LIFR/-RA. Wind SSE 10-15 kt. Wed...IFR/LIFR with RA. Wind ESE at 10-15 kt. Thu...IFR with -SHRA becoming -SN late. Wind NE at 10 kt becoming NW at 20G30 kt late. && .MPX WATCHES/WARNINGS/ADVISORIES... WI...None. MN...None. && $$ SHORT TERM...JRB LONG TERM...DWE AVIATION...MPG
Area Forecast Discussion
National Weather Service Marquette MI
720 PM EDT Sun Mar 10 2019 .SHORT TERM...(This evening through Monday) Issued at 417 PM EDT SUN MAR 10 2019 Water vapor imagery and RAP analysis show a weakening shortwave lifting ne of the northern Great Lakes. Upstream, a shortwave is tracking across MN toward northern WI with a second shortwave trof extending from Hudson Bay to western ND. At the sfc, low pres is located n of Georgian Bay. Rather tight pres gradient btwn this 994mb low and 1027mb high pres over the Plains is leading to increasing winds across the fcst area this aftn with gusts now into 20-35mph range. Snow associated with the departing shortwave has been diminishing and lifting ne today. Shortwave now approaching northern WI should give a boost to the lingering snow late aftn thru mid evening as it catches up to the not yet departed deep moisture associated with the prior shortwave. Model guidance over the last 24hrs, including hourly RAP/HRRR runs since 12z, show an uptick in snow into the nw fcst area during the late aftn/early evening and also into the eastern fcst area during the evening in response to this shortwave. Given the rather vigorous look of the approaching shortwave, have opted to buy into the increase in snow this evening. Signal is stronger over the nw fcst area due to the more pronounced upsloping under brisk westerly winds. There are likely sufficient breaks in the ice cover on Lake Superior to yield a weak lake enhanced component to the snow as well as 850mb temps will be around -8 to -9C. With westerly winds gusting to around 35mph or so, leading to areas of blsn/sharply reduced vis in open areas and the expectation of an additional 1-4 inches of snow accumulation, extended the winter wx advy for Keweenaw/northern Houghton counties until midnight tonight. To the e, will let the ongoing advy expire as scheduled at 21z. Expect an additional 1 to perhaps as much as 3 inches of snow in that area tonight. Will need to watch how snow intensity evolves over nw Upper MI in the coming hrs. If a more substantial increase in snow occurs, may need to issue a new advy over the e during the evening hrs. Trailing shortwave trof currently extending from Hudson Bay to the western Dakotas will reach the Upper Lakes Mon morning. While this will provide some additional forcing late tonight/Mon morning, departure of deeper moisture suggests there shouldn`t be too much response to light LES that will be ongoing under a marginally cold air mass (850mb temps around -14C) following the passage of the other shortwave tonight. Lingering light w to nw flow LES will then diminish/end from w to e on Mon as waa begins/drier air arrives. .LONG TERM...(Monday night through Sunday) Issued at 339 PM EDT SUN MAR 10 2019 With a quiet Tue, attention is on Tue night into Thu night when warm, moist air surges into the region ahead of a strong low pressure system. Ptype is troublesome Tue night as surface temperatures start out below freezing as rain moves in, resulting in some freezing rain, but temperatures will be warming so the threat will not be overly persistent. Current forecast is for a glaze of ice over portions of the central and east. Temperatures will top out in upper 30s to mid 40s Wed and in the 40s Thu with lows Wed night above freezing. Dew points will also be above freezing. Rain is expected more often than not during the period, with potential for 0.75-1.50" of liquid, although some guidance does have up to 2" in spots. Uncertain on exactly how much runoff into streams will occur, but at this point expecting the snow pack to soak much of the precip up. Certainly could see some issues with ponding on water on roads, though. Precip turns to snow Thu night and Fri as the rapidly weakening low and another shot of upper level energy shifts across the area. Plenty of uncertainty in how much snow falls, but not looking like anything too significant at this point. Colder temps Fri into the weekend will, for the most part, put a halt to the melt, leaving us with even more liquid in the very compressed snow pack. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 714 PM EDT SUN MAR 10 2019 At KIWD, expect prevailing MVFR condiitons into Mon morning before improving to VFR. At KCMX, expect conditions varying btwn LIFR and VLIFR early this evening in snow and blsn, then improving to MVFR overnight and to VFR Mon afternoon. At KSAW, MVFR conditions should mostly prevail this evening, then generally VFR overnight into Mon as -sn ends. At all terminals, wnw winds will be gusty to 25-35kt thru early evening before slowly diminishing overnight. && .MARINE...(For the 4 PM Lake Superior forecast issuance) Issued at 417 PM EDT SUN MAR 10 2019 W to nw gales to 35-40kt will continue for much of the night over the e half of Lake Superior in the wake of departing sfc low pres. Winds will slowly diminish from w to e Mon, leading to a period of lighter winds under 20kt Mon night/Tue. Winds will increase again midweek, but gales are not anticipated until possibly late week in the wake of low pres tracking ne across the northern Great Lakes. && .MQT WATCHES/WARNINGS/ADVISORIES... Upper Michigan... Winter Weather Advisory until midnight EDT tonight for MIZ001- 003. Lake Superior... Gale Warning until 6 AM EDT Monday for LSZ248>251-265>267. Lake Michigan... None. && $$ SHORT TERM...Rolfson LONG TERM...Titus AVIATION...Voss MARINE...Rolfson
Area Forecast Discussion
National Weather Service San Francisco Bay Area
845 PM PDT Sun Mar 10 2019 .SYNOPSIS...An upper level low moving south offshore will continue to produce scattered showers across the southern portion of our area through late evening. Dry conditions will return by Monday, but slight rain chances return on Tuesday as a weak cold front moves through the area. Most locations will see little to no precipitation as the system passes on Tuesday. High pressure will build over the West Coast for the remainder of the week and into next weekend, resulting in a warming and drying trend. && .DISCUSSION...As of 8:45 PM PDT Sunday...An upper low is currently centered about 150 miles west-southwest of Monterey Bay and is drifting slowly south. This upper low trigger widespread showers and isolated thunderstorms across our area today. A thunderstorm over the South Bay late this afternoon produce considerable small hail in San Jose, enough hail to cover the ground in some areas. Thunderstorm activity ended around sunset this evening and current KMUX radar shows that shower activity is winding down as well. Currently, showers are mostly confined to areas from southern Santa Clara County into northern Monterey County. 00Z NAM and latest HRRR indicate all shower activity will end by midnight as the upper low continues to drift south and the airmass across our area becomes more stable. Expect dry and seasonably cool weather in all areas from late tonight through Monday. Today`s precipitation may be the last our area sees for a while. A system currently in the Gulf of Alaska is forecast to move to the southeast and sweep across northern California on Tuesday. However, the model trend as of late has been to track this system farther inland and it now appears that little or no rain will fall in our area on Tuesday. The primary impact of the Tuesday system will be the brisk northwest winds that are expected to develop after the mostly dry cold front sweeps through. Winds will increase during the afternoon and remain gusty into the evening, particularly near the ocean where gusts as high as 40 mph are possible late in the afternoon and into the early evening hours. The models are in agreement in maintaining dry conditions for the remainder of the week and into next weekend. Temperatures will start off about 5 degrees cooler than normal on Monday and Tuesday but then gradually warm through the rest of the week as an upper ridge slowly strengthens over California. By next weekend we could see temperatures about 5 degrees warmer then normal with highs in the lower to mid 70s. && .AVIATION...As of 04:28 PM PST Sunday...For 00z tafs. VFR prevailing with scattered showers into this evening. Have observed several lightning strikes this afternoon in the Oakland area and north of San Jose along with reports of small accumulating hail, mainly in the East Bay. Isolated thunderstorms will remain possible around the Bay Area over the next couple of hours before diminishing. Therefore kept VCTS in the Bay Area tafs until 02z. Cigs/vis may lower in thunderstorms and winds will become variable. Cigs have generally been around 3,000-6,000 ft AGL and are expected to improve overnight with mainly clear skies expected by tomorrow. Winds to remain generally light through the period. Vicinity of KSFO...VFR. Isolated thunderstorms to remain possible until around 02z with showers in the vicinity until late tonight. Winds may become more variable during passing thunderstorms/showers along with lowering cigs/vis. Skies to gradually clear into tomorrow morning along with light winds overnight. SFO Bridge Approach...Similar to KSFO except more showers on approach to the south. Monterey Bay Terminals...VFR to brief MVFR possible under passing showers. Shower activity possible through early this evening with a stray thunderstorm possible. Light winds through the period with skies clearing out tonight. && .MARINE...As of 8:09 PM PDT Sunday...Building high pressure will increase northerly winds across the coastal waters tonight and through the coming days. Gale force gusts may be possible late Tuesday. A longer period northwest swell will continue to move through the waters tomorrow as a shorter period west swell dissipates. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Rough Bar Advisory for SF Bar && $$ PUBLIC FORECAST: Dykema AVIATION: AS MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
Area Forecast Discussion
National Weather Service Reno NV
144 PM PDT Sun Mar 10 2019 .SYNOPSIS... Expect a few snow showers along with gusty northeast winds into this evening. A quiet weather day is forecast Monday, with a fast moving cold front bringing strong northwest winds and a brief period of light snow Tuesday afternoon. High pressure returns starting Wednesday with lighter winds, gradually warming temperatures, dry conditions lasting into early to mid next week. && .DISCUSSION... Through Monday... Looking out the window it`s pretty obvious the airmass is quite unstable. Bubbling cumulus that you can watch grow by just staring at them for a few seconds. As such, snow showers will be the main issue for the next 12 hours or so. No major forecast changes. * Scattered mainly instability driven snow and pellet showers are expected through early evening over much of the region. HRRR showing CAPE values 400-600 which is supporting these westward moving cells. Any particularly heavy snow showers could put down a very brief accumulation, but most paved surfaces are warm enough to melt any new snow. A few cells showing reflectivity above 40dBz so some thunder/lightning can`t be ruled out. Any showers persisting after the now later sunset could have more of a road impact but coverage looks isolated. * Main concern area is the Eastern Sierra of Mono County into Mineral County in Nevada. Here there is the instability plus some synoptic forcing for banded snow lasting well into the evening and perhaps the overnight hours. HRRR showing this scenario last several runs. This would yield more accumulation and travel impact post sunset for highways such as 395, 95, and 6. Even at lower elevations a light accumulation is possible. * Monday still looks quiet with (very) shortwave ridging overspreading the region ahead of Tuesday trough/front. GFS has a few light snow showers lingering Monday in the Eastern Sierra otherwise dry with light winds are expected. -Chris Tuesday Onward... No significant changes were made to the forecast from Tuesday through next weekend. For Tuesday`s weak trough passage, the overall timing looks similar with areas of light snow starting in the morning for areas north of Susanville-Gerlach, then pushing southward across I-80 to near US-50 during the afternoon. After sunset, the majority of the snow is likely to be south of US-50 before diminishing by midnight. We`re expecting less than 1" for most areas, with maybe a couple inches in parts of northeast CA/Tahoe and higher elevations of west central NV. Minimal travel impacts are likely as most of the snow will fall during the daytime hours, then after the snow ends, brisk northwest winds should dry out most paved surfaces before road temperatures drop below freezing late Tuesday night. If any icy patches develop, this is more likely late Tuesday night into early Wednesday morning in areas south of US-50 where the window for drying will be shorter, and for the northeast CA/Tahoe regions where road temperatures will cool off more quickly after sunset. For the remainder of the week, we are expecting dry conditions as high pressure develops near the west coast and builds inland. Wednesday will remain brisk and chilly with highs only in the lower- mid 40s for lower elevations and 30s near the Sierra, about 10-15 degrees below average. Then we`re expecting a steady warming trend starting Thursday with light winds each day, leading to some valley inversions and limited mixing especially in the morning. By next weekend, temperatures are likely to reach or surpass 60 degrees in lower elevations, although some of the warmer scenarios bring highs close to 60 as soon as Friday, and above 65 degrees by Sunday. For areas near the Sierra, highs are likely to reach or exceed 50 degrees by next weekend. MJD && .AVIATION... Weakening low pressure dropping along the California coastline combined with an unstable airmass will help generate scattered snow showers into this evening across portions of the Sierra and Western Nevada. Quiet weather is expected Monday before a fast moving cold front briefing strong NW winds and a brief period of light snow Tuesday afternoon. For RNO,CXP: Latest HRRR simulations show continued risk of MVFR periods in snow showers through about 3z/Mon. Quieting down afterward as instability wanes. Generally the warm pavement in mid-March will melt most snow, but if we were to have a heavy snow shower with visibility below 1SM then can`t rule out a very temporary light accumulation under a half-inch. For TVL,TRK: Latest HRRR simulations show continued risk of MVFR periods in snow showers through about 5z/Mon. Quieting down afterward as instability wanes. Generally the warm pavement in mid-March will melt most snow, but if we were to have a heavy snow shower with visibility below 1SM then can`t rule out a very temporary light accumulation. Any snow after sunset also has better chance of accumulating. Up to one inch possible. For MMH: Unlike this morning, MMH is probably more in the focus for snow late this afternoon into the evening. Best forcing and instability are projected for eastern Sierra during this timeframe. Periods of MVFR to IFR snow between 0z and 10z/Mon from latest HRRR. With falling temps some runway accumulations are possible during this timeframe. 9/10 chance of 1", 4/10 chance of 3"+. -Chris && .REV Watches/Warnings/Advisories... NV...None. CA...None. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Sacramento CA
204 PM PDT Sun Mar 10 2019 .SYNOPSIS... Scattered showers today, mainly over the foothills and mountains, with a slight chance of an afternoon thunderstorm. Dry Monday, then a weak storm moves through Tuesday bringing light precip to portions of the forecast area. Dry weather follows into the weekend with some breezy north to east wind Wednesday into Thursday. && .DISCUSSION... Closed low off the coast centered near 37N and 124W will stay off the coast and drift southward along the coast tonight. Scattered showers will be popping up this afternoon, mainly over the mountains with some isolated activity for the valley. Snow levels are around 3500 to 4500 feet. Models showing light amounts of snow accumulation over the northern Sierra into the evening before ending. Afternoon instability is indicated in the models with the best chances over the motherlode and places west of the motherlode into the valley and Delta. HRRR indicates some possible thunderstorms late afternoon to early evening in the Delta and over the motherlode. Shower threat ends tonight with drier weather Monday as interior NorCal comes under short wave ridging. Ridge axis shifts through Monday night followed by another short wave trough for Tuesday. Overall precip amounts with this system look light, generally below quarter of an inch for the mountains and probably just hundredths of an inch accumulating for parts of the valley. Snow levels will generally be in the 3500 to 4500 foot range. Breezy northerly winds will set up behind the weak system Tuesday night into Wednesday and a ridge of high pressure starts to build over the west coast. Warmer temperatures are expected this week with highs in the 60s for the valley and 40s for the mountains after chilly morning starts. && .EXTENDED DISCUSSION (Thursday THROUGH Sunday) Persistent high pressure expected throughout the extended period, bringing dry conditions and warming temperatures. The upper level ridge axis will shift east and center over the Western US Thursday through the weekend. Winds will calm Thursday as surface pressure gradients will relax. Temperatures will warm slightly every day. Models continue to trend warmer with the temperatures, especially over the weekend. Temperatures could top near or in the 70s for most Valley locations this weekend. HEC && .AVIATION... Mainly VFR conditions expected except periods of MVFR/IFR conditions in rain showers today. Showers ending after 00z Monday Sacramento valley and after about 03z Monday northern San Joaquin valley. Winds generally northerly less than 10 knots TAF sites in the valley with gusts to 25 knots over the higher elevations after 00z. && .STO WATCHES/WARNINGS/ADVISORIES... None. && $$