Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/20/19

Area Forecast Discussion
National Weather Service Bismarck ND
1042 PM CDT Tue Mar 19 2019 .UPDATE... Issued at 1042 PM CDT Tue Mar 19 2019 With the latest HRRR/RAP/GFSLAMP trending with little to no stratus central ND late tonight through Wednesday morning, have opted to improve sky grids to clear/partly cloudy, and warming afternoon high temperatures across central ND. Still cooler across the James River Valley where the cooler 925mb-850mb temperatures will reside. UPDATE Issued at 917 PM CDT Tue Mar 19 2019 Latest 00Z NAM and high resolution model guidance not as aggressive with light freezing drizzle potential, thus will leave the previous forecast as is. The NBM and HRRR still fairly pessimistic with higher low level RH fields working their way north to south overnight and lingering through the day Wednesday, resulting in plenty of clouds for central ND. The RAP has been trending with less RH and consequently less clouds for central ND. Believe the previous forecast has the correct trends overnight through most of Wednesday morning. At this point, will continue to monitor upstream observations overnight and assess the rest of the 00Z data to get a better handle on what is to come for Wednesday afternoon. No changes with this update. UPDATE Issued at 640 PM CDT Tue Mar 19 2019 Latest surface map shows a warm front/southern Manitoba and cold front/central central Manitoba, with pressure falls occurring well ahead of it into most of North Dakota. High clouds this evening are forecast to be replaced by stratus after midnight, dropping from north to south. High 925mb RH fields evident on the models and can be seen on the visible satellite imagery loop over northeast Manitoba. Concern now is for patchy light freezing drizzle as enough weak upward vertical motion is being advertised in the BUFKIT soundings per GFS/NAM/RAP/HRRR as well in the high resolution ARW/NMM. However not all models develop precipitation as the cloud depth needed for light freezing drizzle (at least 3200ft thick) and upward vertical motion/omega (at least -5 microbars /sec) are marginally being met. Will monitor the upstream stratus and look more into the 00z data/soundings for possibly adding a mention of light freezing drizzle. Current forecast is on track. && .SHORT TERM...(This evening through Wednesday) Issued at 318 PM CDT Tue Mar 19 2019 A western upper level ridge and a northern Hudson Bay low will keep northerly upper level flow across North Dakota. A mild pacific airmass will be maintained west/southwest of North Dakota, while the cooler air of the Hudson Bay low will persist to our north and east. Currently, an h850 warm front was moving southeast across the state following this morning`s cold front, with mainly clear skies over western ND but high level clouds moving southeast across Manitoba into central and eastern ND. This will be followed by another upper level shortwave and h850 cooling tonight...with the upper level low moving southeast across western Ontario into the Great Lakes, and mainly affecting central and eastern North Dakota with some lower and mid level clouds and cold advection. Models are suggesting the lower stratus clouds may even reach portions of western North Dakota late tonight and Wednesday morning, and lingering in central North Dakota for most of the day. The northwesterly, then more northerly winds expected tonight with this system help prohibit fog formation tonight. Regarding any precipitation, the main forcing associated with the upper level shortwave should mainly affect areas to the east of North Dakota. The forecast cloud cover will act to keep temperatures from dipping into the teens tonight, but the now-expected stratus cloud cover on Wednesday will have a big effect on expected high temperatures Wednesday. Still expecting temperatures to reach into the lower/mid 40s in the far west, but temps should remain in the 30s in central North Dakota with cloud cover lingering until later in the afternoon. .LONG TERM...(Wednesday night through Tuesday) Issued at 318 PM CDT Tue Mar 19 2019 A roller coaster in temperatures for the long term forecast period with chances of rain/snow Saturday-Sunday. This pattern will be very favorable for widespread snow melt across western North Dakota. We expect to begin to see some rises on rivers and streams as water from the melt begins to flow into the system. Warm advection kicks in for Thursday as the stratus clouds and cooler air on Wednesday exits the area Wednesday night. We should see highs Thursday from the upper 30s/lower 40s in the James the 40s over the rest of central ND, and upper 40s/lower 50s in western ND under mostly sunny skies. On Friday another intrusion of cooler air from central Canada will keep temperatures in the 35-40F range over central ND and in the mid and upper 40s in the west. Saturday...A developing low pressure system over the 4-corners will develop on Thursday and Friday, despite the upper ridge that reaches well north into western Canada. The models are in better agreement developing the low northward along the Front Range of Colorado/Wyoming Friday night, reaching the border of MT/SD/WY on Saturday. This will bring mild temperatures to western and central North Dakota, but also a chance of rain during the day and rain/snow Saturday night as the low meanders eastward into eastern SD/NE Saturday night and Sunday. On Sunday, look for cooler conditions with brisk northerly winds as cold air from central Canada plunges southward. Expect highs Sunday from the 30s over central ND to the lower 40s in the far west, with chances of rain or snow across southern ND...and lows Sunday night in the teens and lower 20s. After another cool day Monday, warmer conditions expected on Tuesday. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 1042 PM CDT Tue Mar 19 2019 A weak cold front is forecast to move from central Manitoba and just graze central ND overnight. Behind the cold front will be an area of stratus, likely impacting KJMS late tonight through Wednesday morning. As of this update, the stratus may or may not continue through Wednesday afternoon at KJMS. Will know more with the 06z taf issuance. The rest of the terminals are expected to remain in VFR conditions. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...KS SHORT TERM...JV LONG TERM...JV AVIATION...KS
Area Forecast Discussion
National Weather Service Wilmington NC
1006 PM EDT Tue Mar 19 2019 .SYNOPSIS... Developing low pressure off the SC Coast tonight will move northeast along the immediate NC Coast Wed into Thu. Patchy light rain along the coast late tonight, will become more widespread and push further inland during Wed. The rain will end early Thu as the low lifts further north, away from the forecast area. A cold frontal passage will occur late Fri followed by seasonable high pressure for the weekend. A frontal boundary accompanied with scattered showers will slowly drop south across the region early next week. && .NEAR TERM /THROUGH WEDNESDAY NIGHT/... As of 830 PM Tuesday...Latest HRRR and HiResW indicate patchy light rain late tonight and will back the rain potential to late tonight in the 15 to 24 percent range with the hier side of this range along the immediate NC coast and adjacent waters. The inland SC zones should remain mostly dry. Protected areas from north-northeast winds west of the I-95 corridor could see patchy frost before more opaque ci moves in as well as low level stratocu from the east. Sfc dewpts will be in the upper 20s to low 30s and do expect up to 5 degree sfc dewpoint depressions. Winds may briefly go calm or decouple at the far NW portions of the FA but overall do not expect a widespread frost with min temps dropping to 36 to 39 degrees. This may require a SPS. Previous...................................................... As of 300 PM Tuesday...Tricky forecast on tap for the near term period. First off, with temps mainly just getting down into the upr 30s tonight (mid 30s though in coldest spots), not expecting much in the way of frost with ~5 kt wind and dewpoints down in the upr 20s. Exception may be over far western areas where patchy frost is possible. Surface high pressure north of the area this aftn slides offshore tonight. Meanwhile, coastal low pressure gradually develops just offshore through Wednesday as a mid-level shortwave trough approaches from the west. Result will be increasing chances of rain from east to west through the day Wednesday, continuing into Wednesday night, in response to increasing low-level convergence and isentropic upglide. PoPs increased to 60-70% for eastern areas where the rain may be moderate to possibly heavy at times. As for temps, expect only highs in the 50s Wednesday due to NE flow and a cloudy sky. Lows temps Wednesday night mainly 40-45. && && .SHORT TERM /THURSDAY THROUGH THURSDAY NIGHT/... As of 300 PM Tuesday...Surface low will lift off to the north as potent shortwave crosses the Carolinas on Thursday. Any lingering pcp from sfc low will move out of the area Thursday morning. Dry air will wrap around the back end with some clearing through the day, but mid to upper shortwave will ride through later in the day with mainly clouds, but may see some light pcp mainly to the north of local area over NC. Deep NW flow will develop through Thurs night on back end of shortwave moving out of area. This will give a little punch of CAA. Overall, expect some clouds mixing with sun and low end pcp chc on Thurs, but weather improving through Thurs night. Temps should be near seasonable through the period with overnight lows in the 40s and && .LONG TERM /FRIDAY THROUGH TUESDAY/... As of 300 PM Tuesday...High pressure will build in slowly from the west and will migrate eastward through the weekend at the same time as mid to upper ridge builds over the area. Overall, expect a dry weekend with plenty of sunshine and warming temps. The dry air mass in place will allow for some large diurnal temp swings with afternoon highs just above normal and overnight lows just below. The center of the high will shift off shore Sunday night into Monday. This will produce a southerly return flow which will help to increase the temps and moisture, leading to some clouds mixing with the sunshine on Monday, but temps warming into the 70s. By Mon night into Tues, mid to upper trough will dig down over the Southeast. This will help to deepen sfc low as it tracks east toward the coast while at the same time, a cold front will drop down from the north. This will help to spread clouds and pcp into the Carolinas Mon night into midweek. Cooler air behind the front will drop temps quite a bit for Tues. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... As of 00Z...Low pressure developing off the SE US coast will move northward overnight. This has already started to bring in a mid- level deck along the coast and this will continue overnight. Expect MVFR conditions to develop on Wednesday morning. MVFR will be more likely along the NC coast with SC terminals approaching MVFR later in the morning. As of right now, most models have the developing low pressure system remaining well offshore which will bring light rain to ILM, with only VCSH throughout the day at coastal SC terminals. A feed of low-level marine moisture could lead to the development of IFR conditions along the coast with low stratus the primary threat, late Wednesday afternoon; MVFR elsewhere. Showers ending after the end of the forecast period. Northeast winds 5-10 knots increasing throughout the forecast period. Extended Outlook...Likely MVFR late Wednesday through Thursday with storm system. VFR returns Friday into weekend. && .MARINE... As of 900 PM Tuesday...SCA conditions to continue across all waters. Models are in decent agreement in developing a kink in the sfc pressure gradient where the sfc low will develop on it. This kink will extend from 41013 northwest to the Cape Fear region overnight into Wed. Looking at winds becoming ENE to E north of the kink and NNW-NNE south of this kink. Wind speeds will increase to a solid 20 to 30 kt in the vicinity of this kink with few to occasional gusts to Gale force. Significant seas will further build from Cape Fear northward with double digits possible...and hold steady south of the Cape as the fetch decreases-some. Previous.......................................................... As of 3 PM Tuesday...Small Craft Advisory continues over all waters for a prolonged period of 15-25 kt NE winds with gusts up to 30 kt. This as strong high pressure anchors off to the NE and surface low pressure develops just offshore late Wednesday. Winds may diminish as the center of low pressure moves directly over the local waters Wednesday night, but continued high seas may warrant an extension to the current Small Craft Advisory end time (midnight Wednesday night). Offshore flow will develop as high pressure begins to build in behind departing low on Thursday. The diminishing off shore flow will allow seas to subside from advisory levels Thurs morning down to 3 to 5 ft by end of the day. Gradient will remain a bit tight, though, as high pressure builds down and low strengthens off the coast of New England into Fri. Therefore winds may increase again Thurs night into early Fri, with seas slower to drop, especially in the outer waters Fri. By the weekend, winds will lighten as high pressure migrates slowly eastward reaching overhead by Sunday. This will produce improving marine conditions over the weekend with seas 2 to 4 ft on Sat and down less than 2 ft on Sunday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...None. NC...Coastal Flood Advisory until 11 PM EDT this evening for NCZ107. MARINE...Small Craft Advisory until midnight EDT Wednesday night for AMZ254-256. Gale Warning until 3 PM EDT Wednesday for AMZ250-252. && $$ SYNOPSIS...DCH NEAR TERM...DCH/MAS SHORT TERM...RGZ LONG TERM...RGZ AVIATION...21
Area Forecast Discussion
National Weather Service Key West FL
940 PM EDT Tue Mar 19 2019 .DISCUSSION... After a lull in the precip activity across the Keys during the late afternoon hours, stratiform rain coverage and embedded shower coverage has increased once again during the mid evening, although most of the rainfall remains light at this time. Skies are cloudy over the Keys, with temperatures mostly in the lower 70s, and winds on land from the northeast at 15 to 20 mph. Surface analysis indicates that a weak low pressure area is likely located near the northwest coast of Cuba, while water vapor satellite imagery shows one more disturbance moving eastward across the southeastern Gulf, with a much drier airmass filling into the central Gulf behind this feature. The 00Z Key West sounding remained very moist with PW of 1.74 inches, which is well above the 90th percentile for this date. In the short term, expect mostly stratiform light to moderate rain to continue across the Keys for the rest of the evening. An isolated embedded heavier shower or even a thunderstorm cannot be ruled out over the island chain, but it is more likely that any thunderstorms will remain over the Straits and south of the Keys. As the disturbance currently in the SE Gulf moves quickly eastward across the Keys late tonight, shower activity should taper off over the Keys and Gulf waters as the primary area of deep moisture and lift shifts SE into the eastern Straits. Otherwise, windy conditions should also taper off late tonight, and low temps should drop only a few degrees into the upper 60s. The public forecasts have been updated to reflect the above thinking. A much drier pattern remains on track for the Keys beginning Wednesday, with rain chances tapering off to slight, then none by Thursday afternoon. Expect mostly clear, dry and seasonable weather for Thursday through Saturday, with highs in the upper 70s to near 80 and lows in the mid 60s to near 70. Scattered showers may return to the area beginning Sunday and continuing into early next week, but recent model guidance has trended drier, and later shifts may reduce rain chances for those periods. && .MARINE... NE winds have gradually decreased across much of the Keys coastal waters during the evening, but recently surged back up to 27 knots sustained at Pulaski Shoal Light. This may be due to the low pressure area passing to the south of the western Straits at this time. Winds are currently running below 20 knots at most of the other reporting sites, but short-range model guidance suggests that winds will surge back up above 20 knots across much of the marine area during the next several hours as the low passes to our south. Will maintain the Small Craft Advisory for all zones with the late evening forecast issuance. We do expect winds to begin decreasing toward morning, and to continue dropping on Wednesday. && .AVIATION... Large area of light to moderate stratiform rain will spread across the terminals for the rest of this evening. Heaviest rain with lowest cigs/vsbys will come later this evening in the 02z- 05z time frame. During that time, cigs below 010 and vsbys in the 4- 6SM range are possible, as indicated in GFS statistical guidance. Heavier rain should then taper off to showers before midnight. The boundary layer will remain richly moist into Wed morning, with GFS LAMP guidance carrying MVFR cigs in the 010-020 range until 17z at EYW. Have only shaved this expectation a little with scattering indicated at 16z (noon) in the TAFs. The HRRR even shows cigs hovering just below 010 on a temporary basis as late as 14z-15z on Wed morning. Expect rapid scattering and lifting of cloud bases after about 16z to 17z. && .CLIMATE... On this date in Florida Keys weather history, in 2003, the low temperatures at Key West (78F) and Marathon (79F) were both warmer than the high temperatures recorded today. The high at Key West today was 75F and at Marathon it was 77F. The low at Marathon on March 19th, 2003 was the first of 3 days in a row with a low temperature of 79F, tying as the warmest low temperature ever recorded in the month of March. && .KEY WATCHES/WARNINGS/ADVISORIES... FL...None. GM...Small Craft Advisory for GMZ031>035-042>044-052>055-072>075. && $$ Public/Marine........Jacobson Aviation/Nowcasts....Haner Data Collection......DR Visit us on the web at Follow us on Facebook and Twitter at:
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1027 PM EDT Tue Mar 19 2019 .SYNOPSIS... High pressure will build in from the northwest tonight. Low pressure will develop to the south Wednesday and lift north across the area Wednesday night. The low will lift north of the region later Thursday pushing a cold front offshore Thursday night. High pressure will build into the area late week and into the weekend. Low pressure is expected to impact the region early next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... As of 1015 PM Tuesday...Area of sprinkles or light showers now stretches from the western Albemarle Sound south and southeast to Cape Lookout, with latest HRRR suggesting light sprinkles or showers could persist over this area for much of tonight. Have added slight chance PoPs for the eastern half of the CWA for this light precipitation. Weak convection continues adjacent to the Gulf Stream, 20-40 nmi from shore. High pressure will continue to build south over the area tonight. Meanwhile, low pressure is forecast to develop along a front stalled to the southeast off the coast. As the low develops it will push a trough of low pressure toward the NC coast late tonight. Sky cover will continue to increase overnight and especially for coastal sections. Heavier showers will remain offshore tonight, then could move onshore late tonight as the through gets closer to the coast and have continued chance/slight chance coastal PoPs late. Temps will be 35-40 inland and 40-45 coast. Continued breezy to windy tonight, esp along the coast, as gradient tightens between the high to the west and the through off the coast. && .SHORT TERM /WEDNESDAY/... As of 325 PM Tue...The trough of low pressure will move slowly and should be along the coast late Wed. Showers will become more numerous and penetrate further inland, especially in the afternoon. PoPs will increase to likely most areas in the afternoon. Precipitation amounts will be quite variable, but could be as high as .50-1" in frequent showers which are most likely to occur vicinity of the coast. Highs will be in the mid to upper 50s. Continued breezy to windy in the morning, esp along the coast, then winds should slowly diminish in the afternoon. && .LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/... As of 300 PM Tuesday...An area of low pressure will lift across the area Wed night into Thu bringing a period of unsettled weather and breezy conditions. High pressure will build over the area this weekend bringing dry wx and a warming trend. Temperatures will be near to slightly below through the week, then warm to slightly above normal early next week. The next system look to impact the area Mon night and Tue. Wednesday night through Thursday night...A robust upper trough will approach the area Wed night and this will lift surface low pres N across the region Wed night with it lifting N of the region later Thu. Most all mdls show decent amount of moisture and rain spreading across the region with the sfc low Wed night and early Thu. Have increased pops to likely inland and categorical coast Wed night. Given low track just inland added some thunder to imd cst/cstl wtrs Wed night. As the low lifts to the N later Thu precip shld taper off and end from SW to NE in the aftn. Much drier are will spread in Thu night as cold front trailing low pushes offshore. Lows Wed night will be mild with 40s inland to 50s beaches. As precip tapers of Thu and skies brighten some in aftn temps expected to reach low/mid 60s. Lows Thu night will range from lower 40s inland to mid/upr 40s cst. Friday through Monday...The upper trough pushes offshore Fri with height rises through the weekend with an upper ridge and surface high pressure becoming centered over the area Sun. The high will drift offshore Mon with a complex system approaching from the west. Dry conditions continue over the weekend with a gradual warming trend early next week. Some guidance is showing light showers developing across the area Mon and cont slight chance PoPs. Highs expected to continue in the low to mid 60s inland to mid 50s coast Fri and Sat. Temps expected to warm into the upper 60s to lower 70s inland to low to mid 60s coast Sun. Some mid 70s poss Mon inland with SW flow on backside of high. Mon night and Tue...Next short wave and low pres system will impact the area this period. Long range mdls look quite wet and windy with this system but given timing and track uncertainty this far out will keep pops in chc range. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Short Term /through Wednesday/... As of 725 PM Tuesday...Expecting VFR conditions through Wed morning as high pressure prevails across the area. Some mid level broken clouds currently for TAF sites, though should remain VFR overnight. By Wed afternoon a trough of low pressure will form along the coast resulting in scattered to numerous showers with brief sub-VFR conditions possible. Late Wed ceilings are forecast to become sub VFR and showers will become numerous. Long Term /Wednesday night through Sunday/... As of 300 PM Tuesday...Good cvrg of rain expected Wed night as low pres lift N across area...bouts of sub VFR a good bet. Precip will taper off from S to N Thu as low lifts N of region and shld grad see VFR return. VFR expected Fri through Sun as high pres builds across with dry air over region. && .MARINE... Short Term /through Wed/... As of 1025 PM Tue...Latest surface and buoy data indicate NE winds 20-30 kt with seas 5-8 ft across the waters. Strong winds and elevated seas will continue Wednesday. N/NE winds 20-30 kt with gusts 35-40 kt south of Oregon Inlet where Gale Warnings are in effect. These winds will continue through early Wed in response to the gradient between high pressure to the north and low pressure to the south. Seas will build to 7-10 ft tonight. The winds are forecast to become E/SE Wed and decrease to 15-25 kt as a trough of low pressure moves along the coast. Seas however, will remain 7-10 ft as the flow becomes SE and begins to increase again late. Long Term /Wednesday night through Sunday/... As of 300 PM Tuesday...Low pres will lift N inland from cst Wed night then cont to move N of region later Thu. Expect gusty E to SE winds ahead of low Wed night that will grad shift to WNW and remain gusty later Thu. Cold advection and decent grdnt will keep NW winds gusty Thu night into Fri. NW winds increase a bit later Fri night and early Sat as secondary surge of cold air crosses. Winds diminish and become light Sat night into Sun as high pres builds in. Seas will be in the 6 to 10 ft range Wed night and slowly subside to 5 to 8 feet Thu. Seas will be mainly in the 4 to 6 foot range Fri into Sat with gusty offshore flow. Seas will subside to 2 to 3 feet later Sat night and Sunday. && .TIDES/COASTAL FLOODING... As of 3 PM Tue...Persistent gusty NE flow combined with high astronomical tides could lead to minor water level rises for areas adjacent to the Southern Pamlico Sound through tonight...from Downeast Carteret County over to areas along the Neuse River and adj. creeks. Rises not expected to exceed 0.5 ft above ground or 1 ft above normal at this time. Gusty SE flow Wed night will lead to higher than normal water levels along the south facing beaches and may also need High Surf Advisory as waves in surf zone approach 8 ft. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...Small Craft Advisory until 2 PM EDT Wednesday for AMZ130-131- 135. Gale Warning until 8 AM EDT Wednesday for AMZ152-154-156-158. Small Craft Advisory until 6 PM EDT Friday for AMZ150. && $$ SYNOPSIS...MHX NEAR TERM...DAG/JME SHORT TERM...JME LONG TERM...RF/SK AVIATION...DAG/RF/JME MARINE...DAG/RF/JME TIDES/COASTAL FLOODING...MHX
Area Forecast Discussion
National Weather Service San Francisco Bay Area
643 PM PDT Tue Mar 19 2019 .SYNOPSIS...A cooling trend will begin today as cloud cover increases over the region ahead of an approaching weather system. Rain showers will develop over the region tonight into Wednesday with an unsettled pattern likely to continue through late week. While dry conditions are possible this weekend, unsettled weather will return heading into next week. && of 02:40 PM PDT Tuesday...A negatively tilted trough continues to slowly approach California from the west this afternoon. This storm system is aligned nearly parallel with the coastline from Point Arena through Santa Barbara and has already brought increased cloud cover, cooler temperatures, and higher humidities to the region thus far today. Southerly winds will progressively strengthen ahead of the cold front through the remainder of the day, becoming gusty (peak gusts up to 40-50mph in the windiest spots) along the coast and over the higher terrain with breezy winds elsewhere. Latest KMUX radar imagery is detecting light reflectivity returns ahead of the leading edge of a cold frontal boundary approximately 60 miles off of the coast. Despite the close proximity to the area most models delay the onset of precipitation moving inland until much later this evening, owing to the negative tilt and sluggish speed of the parent trough. The latest model output has decreased the overall precipitation intensity and coverage versus previous runs. Storm total precipitation will range from 1.25-2.25" for the higher terrain of the Santa Cruz and Big Sur mountains while urban areas will generally range from 1/5" to 1/3", with rain shadowed areas on the lower end of the spectrum. HRRR model output confines precipitation mostly in broken bands and scattered showers wrapped closely on the eastern flank of upper low as it lifts northeastward across the region. Previous model runs showed somewhat more organization and strength than the current runs and have reduced overall QPF as a result. Models generally agree that precipitation should begin to spread inland between 10pm and midnight tonight, however, a few precursor showers could arrive in time for this evenings outbound commute. Rain intensity and coverage should scale upwards after midnight as the upper low shifts inland and lifts northeastward over the San Francisco Bay Area. Isolated thunderstorms will be possible overnight tonight through Wednesday morning due to an increasingly unstable environment advecting into the region. The overall weaker model output from the latest runs may increase the potential for thunderstorms Wednesday as a result increased cloud breaks leading to more surface heating and further destabilization of the atmosphere. A secondary vorticity pulse on the rear flank of the broader trough will descend into the local area later Wednesday into Wednesday night and extend the possibility of a few lingering showers potentially into early Thursday. Confidence is relatively low regarding how this second disturbance will interact with the initial disturbance with some models introducing an increased chance of showers over the higher terrain into Thursday morning. A transitory high pressure ridge will develop by midday Thursday allowing for a brief warming/drying trend, however, another storm system is set to descend into the region from the Gulf of Alaska by Friday morning. Fridays storm system will move from north to south and bring the bulk of any precipitation to the North Bay. Precipitation along the North Bay coastal range could approach 1.00" while the North Bay valleys pick up 1/2 to 2/3". Much less precipitation is expected south of the Golden Gate, with 1/4 to 1/3" in the immediate SF Bay Shoreline, and progressively less farther southward. Drier weather will prevail through most of the weekend with a slight warming trend into Sunday but a third storm system will begin to advance on the region early next week. Forecast models and ensemble members continue to pepper later Monday through early Wednesday as wet time periods, however, there is still a bit too much noise to pin down exactly when, where, and how much to expect. && .AVIATION...As of 6:43 PM PDT Tuesday...Increasingly strong and gusty winds through the evening, low level wind shear developing nearest the coast with some overlap into the South Bay, possibly extending to the East Bay and North Bay later this evening. Showers arriving later in the evening into Wednesday. Terminals reporting VFR thus far. An amplifying and negatively tilted 500 mb height trough is approx 200 miles southwest of Monterey county and moving north and will sweep over the area through the evening and overnight. Showers on Wednesday. NAM model shows fairly rapid cold air advection through 06z, near 7 Celsius cooling at 925 mb and 850 mb levels and thermal troughing embedded with the 500 mb height trough indicating this trough has a fair amount of dynamics and lift with it. Expect rapidly changing weather conditions at least through the evening. Clouds looking convective southwest of SLO county, but not seeing lighting yet; echo tops near 20 thousand feet. There`s a slight chance of thunderstorms mainly late tonight into Wednesday morning. Vicinity of KSFO...Increasingly strong and gusty winds through the evening. Wind flow tending to downslope, dry out any chance of showers in nearest term. Low level wind shear developing by mid to late evening and lasting into early Wednesday morning. Showers arrive overnight. VFR decreasing to MVFR ceilings late tonight into Wednesday morning. VFR Wednesday with a few showers. SFO Bridge Approach...Similar to KSFO. Monterey Bay Terminals...VFR, increasing winds. Wind flow is downsloping and drying in lee of the Santa Lucia mountains drying out any chance of showers in nearest term. Expect rapidly changing weather through the evening including low level wind shear through the evening into early Wednesday morning. Showers expected to arrive overnight into Wednesday. MVFR ceilings in showers. VFR Wednesday and lingering showers. && of 5:18 PM PDT Tuesday...Southerly winds will continue tonight ahead of an approaching low pressure system and cold front moving in from the west. Winds will increase overnight and tomorrow before winds veer to the west to northwest later tomorrow. A long period west swell will continue into this evening increasing shoaling on bars and harbor entrances. An additional long period west to northwest swell will arrive towards the end of the week. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...Pt Reyes to Pigeon Pt 0-10 nm SCA...Pigeon Pt to Pt Pinos 0-10 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...SF Bay from 3 AM SCA...Pt Arena to Pigeon Pt 10-60 nm from 3 AM SCA...Pt Arena to Pt Reyes 0-10 nm from 3 AM SCA...Rough Bar Advisory for SF Bar from 9 PM SCA...Mry Bay && $$ PUBLIC FORECAST: DRP AVIATION: Canepa MARINE: AS Visit us at Follow us on Facebook, Twitter, and YouTube at:
...Update to aviation forecast discussion...

.SHORT TERM...(This evening through Wednesday night) Issued at 340 PM CDT Tue Mar 19 2019 As of 20Z Tuesday afternoon a midlevel shortwave trough was centered across the NE panhandle with an attendant surface trough extending from near Wichita, KS to near Hiawatha, KS. A band of post-frontal rain shower activity continues to progress eastward across the forecast area. The primary concern through the remainder of the short-term period is enhanced rainfall rates due to shallow convection that could lead to brief heavy rainfall. RAP and HRRR forecast soundings continue to suggest upwards of a 50 J/kg of MLCAPE may reside ahead of the boundary, which may briefly increase rainfall rates. Generally additional rainfall amounts of 0.10" to 0.50" can be anticipated with lowest amounts south of I-70 and the higher amounts north of I-70. Temperatures have rapidly warmed southeast of the surface front with deep mixing of the boundary layer in upwards of 700 mb. This has resulted in surface temperatures surging into the 60s, especially along and southeast of the KS turnpike. In addition, southwest winds have gusted upwards of 30-35 MPH in portions of east-central KS, where boundary layer mixing has been maximized. Some fire danger concerns will continue through the remainder of the afternoon across east-central KS given the gusty winds and relative humidity values in the 20 to 30 percent range. Rich soil moisture and decreased fuel load due to flattening of grasses from multiple winter snow events should mitigate fire concerns through the short term period. Post- frontal temperatures have generally decreased into the 40s. This trend should continue into the evening with temperatures rapidly decreasing behind the cold front. Transitioning into tonight, the main midlevel shortwave and attendant surface trough will progress east of the forecast area ending precipitation from west to east. All precipitation is expected to exit the area by 09Z. A secondary midlevel shortwave trough is progged to traverse portions of the Great Lakes region through the day Wednesday, shunting a secondary weak surface boundary through the CWA late Wednesday afternoon into the evening. Ahead of the front winds will veer to predominately a west direction through the lowest 5kft of the atmosphere. With the downslope component combined with deep boundary layer mixing, upwards of 850 mb, will yield mild temperatures in the 50s to near 60 area-wide. Limited moisture should yield a dry frontal passage as winds veer to the north Wednesday night. Surface high will build into the area Wednesday night as low temperatures reach the low to middle 30s. .LONG TERM...(Thursday through Tuesday) Issued at 340 PM CDT Tue Mar 19 2019 A highly amplified midlevel ridge axis will overspread the central US Thursday into Friday, ahead of a midlevel low across the western US. Temperatures Thursday and Friday are progged to reach the upper 50s and lower 60s. The midlevel low will become cutoff by weeks-end and begin to fragment into multiple shortwave troughs. Precipitation chances look to increase late Friday into Saturday as the initial shortwave traverses the Plains. Rain chances will persist into early next week as additional shortwave troughs traverse the Plains. Lapse rate profiles continue to show a weak signal given the weak nature of the midlevel trough. Temperatures look to remain quite mild with highs in the 50s and 60s into next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 630 PM CDT Tue Mar 19 2019 Band of showers will bring some reduced visibilities to TOP and FOE over the next few hours, with MVFR cigs expected to move into all terminals by 03Z. Based on MYZ observations, will include some IFR cigs at MHK for a few hours and could see these conditions be more prevalent through much of the night. VFR conditions should return by 17Z with dry air on west winds building in. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Baerg LONG TERM...Baerg AVIATION...65
Area Forecast Discussion
National Weather Service Las Vegas NV
830 PM PDT Tue Mar 19 2019 .SYNOPSIS...Cloud cover is expected to increase through tonight and precipitation chances will begin to increase from west to east this evening through overnight tonight. Unsettled weather will continue through Thursday with valley showers and mountain snow. Expect a brief break on Friday before another weather system moves into the region by Saturday. && .UPDATE...Scattered showers ahead of negatively tilted trough over northwest San Bernardino County and southern Inyo County will continue to develop and drift northward overnight. So far, rain buckets across the southern Sierra reporting less than a tenth of an inch of rain over the past 3 hours. HRRR and HREF simulations quite similar tomorrow depicting a more widespread band of precipitation across Lincoln County, southwest Utah and northern Mohave County tomorrow afternoon. A more broken line develops across Nye, Clark and northeast San Bernardino Counties late afternoon and evening. Updated the POPs based on the hi-res model output the rest of tonight which keeps the highest POPs across Inyo County. No other changes. && .DISCUSSION...Today through Monday. The latest satellite imagery shows scattered high clouds beginning to fill in across the region with some cumulus developing mainly near higher terrain this afternoon. These trends will continue through this evening with cloud cover increasing as an approaching negatively tilted trough continues to dig into our region. Moisture is fairly limited with this system but isolated to scattered showers will begin to increase later this evening across Inyo County. As the trough digs further into SoCal tomorrow, upper level difluence and daytime heating will provide enough forcing and lift to initiate showers and isolated thunderstorms across the Mojave Desert. The low will eventually cut off overhead on Thursday before lifting off to the northeast early Friday continuing precip. chances through that time. Decent instability will be in place on Thursday across the region allowing for more scattered thunderstorm chances mainly across southern NV and northwest AZ. With marginal moisture and dry low levels, storm totals are not expected to be impactful. Snow levels will start off around 7500-7000 feet and begin to drop overnight Wednesday to around 5500 feet. Again, with marginal moisture, 48+ hour snow totals are 7-10 inches above 7000 feet along the eastern Sierra, 4-6 inches in Lee Canyon and only 1-2 inches in Kyle Canyon. Low amounts over a 48+ hour period should limit impacts and no winter weather products are expected. Besides precip./thunderstorm chances, no other impacts are expected with the mid-week weather system. Winds will be breezy from the south- southeast through this evening across much of the region. Some breezy to gusty southeast winds will be possible across areas north and east of Clark County tomorrow afternoon as the trough digs into southern NV and pressure gradients increase across those areas. Of course with any thunderstorm activity, winds may be variable and gusty. By Friday, a shortwave ridge will briefly be overhead in the afternoon pushing any lingering moisture northeast. The break in clouds and storm chances will be very brief though as another trough is progged to dig into the Great Basin region overnight Friday into Saturday. This next system will be fast moving and should keep precip chances confined to south-central NV. Another ridge will move overhead Sunday bringing mostly sunny skies through Monday. && .AVIATION...For McCarran...Light easterly winds are expected at the terminal through the rest of the afternoon and evening before turning back to the southeast overnight remaining below 10kts. An increase in cloud cover is expected gradually throughout the day aoa 10kft. An incoming system tomorrow should further increase cloud cover and shift winds to the south in the afternoon. Could become gusty as well. For the rest of southern Nevada, northwest Arizona and southeast California...An incoming storm system over the next 24 hours will first impact KBIH with gusty south winds and an increase in cloud cover and -SHRA by late this evening. KDAG will also see a response in winds, initially being out of the southeast and shifting to southwest late this afternoon. Minimal impacts expected at KVGT/KHND/KEED/KIFP. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Pierce DISCUSSION...Kryston AVIATION...Boucher For more forecast information...see us on our webpage: or follow us on Facebook and Twitter