Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/17/17

Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
809 PM CDT Sun Jul 16 2017 .DISCUSSION...Updated grids to trim back precip chances through overnight period. Despite a lingering shower over Starr County at this time, will limit PoP to 20% all areas through 06Z, then only increase to 30% along the coast from 06-12Z. Even with abundant moisture evident (2.17" of PW on 00Z BRO raob), don`t think the vort max drifting across the area overnight will be enough forcing for scattered precip to re-develop (per upstream satellite trends), except perhaps along the coast. 23Z HRRR supports this idea, as well. Also updated hourly temps to better reflect observational trends, especially out west where showers and storms occurred earlier. All products updated and disseminated. && .PREV DISCUSSION... /issued 638 PM CDT Sun Jul 16 2017/ DISCUSSION...Updated for latest aviation discussion below. AVIATION...Late afternoon/early evening convection waning a bit faster than anticipated, so will only hold onto mention of VCSH until 02-03Z due to boundaries floating around, especially out near MFE. VFR with light winds should prevail through mid-morning on Monday, though a brief shower at BRO or HRL cannot be ruled out. Pretty strong signal in the model guidance that another round of scattered showers and thunderstorms will occur beginning around mid-day tomorrow, as a mid-level disturbance drifts westward across the region. Atmospheric moisture will be abundant, and storm motions indicated on BUFKIT forecast soundings are less than 10 knots during the afternoon, so periods of heavy rain are possible. Have introduced PROB30 groups at all terminals to account for this possibility; MVFR conditions are likely to occur at times in the heavier showers and thunderstorms. PREV DISCUSSION... /issued 313 PM CDT Sun Jul 16 2017/ SHORT TERM (Now through Monday night): Convection has initiated along the seabreeze and also in the northern ranchlands this afternoon. Thunderstorms should expand in coverage as abundant tropical moisture surges northward ahead of a mid-level trough of low pressure moving into South Texas off the Gulf waters. Current model soundings show precipitable water values of 2 to 2.25" across the area, so any thunderstorms that develop have the potential to produce locally heavy rainfall. 12Z model guidance on PoPs still differs slightly with the GFS output being significantly higher than this time yesterday and the NAM being the driest. Decided to increase PoPs only slightly for tonight into Monday with the tricky part being determining what boundaries will be leftover tomorrow and how much instability can recover. Regardless, the trough axis will be moving overhead Monday afternoon with southeast flow aloft, which should support another decent round of precipitation. Still think the better chances overall will be in the northern areas where model guidance shows several vorticity maxima moving across. If training of showers/storms occurs or if storms become attached to slow-moving boundaries, nuisance flooding of streets and low-lying areas will be possible, especially across areas that are already well-saturated from recent rainfall. Isolated amounts of 1 to 2 inches or even locally higher cannot be ruled out. LONG TERM (Tuesday through Sunday): A very broad mid-level height pattern will straddle the Gulf and deep South Texas. High pressure will remain king over the Gulf as well, supporting a weak to mdt anticyclonic southeast flow. A mix of clouds and sun and near normal to slightly above normal temperatures look probable. Isolated Gulf showers will stand up along the way, as will an almost daily sea breeze. A pulse of moisture moving up from the south may provide the best chance of coastal convection on Wed, but each day will hold some potential for an inland marching sea breeze. By mid-week a slightly more enhanced ridge will build over the southern Plains, which won`t do anything to enhance rain chances, but will help nudge high temperatures up a couple of degrees moving into the end of the week and the weekend. Low temperatures will range from the mid 70s to near 80, while high temperatures will be mainly in the 90s to near the century mark Tuesday and Wednesday, with peak upper values creeping up to a few degrees above the century mark late in the period, supporting associated heat index values up to around 105 degrees. MARINE: (Now through Monday night): Surface high pressure over the Gulf of Mexico will maintain light to moderate southeast winds with low seas of generally under 3 feet through the period. The main marine impacts will be from any showers and thunderstorms that develop, which would produce locally higher winds and seas. Tuesday through Friday: Broad high pressure over the Gulf will support light to moderate winds, mainly out of the southeast, and low to moderate seas. Occasional marine convection will develop. && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 53-Schroeder/61
Area Forecast Discussion
National Weather Service Goodland KS
737 PM MDT Sun Jul 16 2017 .UPDATE... Issued at 730 PM MDT Sun Jul 16 2017 Adjusted areal extent and timing of rainfall tonight based on latest near-term data. RAP model seemed to have a decent handle on current storm activity and had done well last night. The frontogenesis in the 600-500mb layer and lift in the 310K through 325K levels indicate the storm activity will develop near the CO/KS border early this evening and be in a north-south line. This lines up well with the 500mb vorticity that will be rotating around the center of the closed upper level low. The storms will move little this evening, so wherever the storms form, they will linger there for awhile. Have good confidence in the location/timing of storms this evening, however confidence is lower for overnight. Models are split with the storms either tracking more north-northeast or northeast. Regardless of the track the storm activity will gradually decline overnight as 500mb vorticity declines. Will hold off making significant adjustments to the rainfall chances for overnight to see how storms develop/move, and see if the data comes into better agreement. && .SHORT TERM...(This afternoon through Monday) Issued at 204 PM MDT Sun Jul 16 2017 Plume of deep moisture continues to linger over our CWA (apparent on WV imagery), with mid-upper low near CO border. This afternoon-Tonight: Thunderstorm activity is already beginning to redevelop along western edge of main instability/moisture axis near the CO state line. Latest RAP analysis indicates SB CAPE in excess of 2000 J/KG and supports ML CAPE increasing to this range within the next few hours. Shear is very weak, so other than less organized isolated stronger cells (marginal hail) main concern continues to be hydro. MOdels show increasing forcing over our CWA as a strong lobe of vorticity on back side of mid level circulation rotates over our CWA this evening and overnight. Result should be increasing coverage, though with CAPE decrease during the evening hours, moderate to occasionally heavy showers may be favored over thunderstorms. I adjusted PoPs/QPF with latest short range consensus blends to match these trends. Monday: Main mid-upper low should be northeast of our CWA, but lingering forcing on back side of system may support continued shower and thunderstorms chances in our northeast and east. Moist/unstable air mass in the afternoon could support isolated activity further west near building surface trough, but current guidance is favoring our east with possible subsidence in our west. Bulk effective shear should be near or just above 30kt, so with better shear we may have a better chance for severe thunderstorms in our far northeast than we have had over the past few days. Regarding temperatures: As has been the case, cloud cover and linger precip complicate overnight lows, with locations that clear out dropping to near 60F (more likely west). Otherwise, where precip lingers overnight lows may not drop much lower than the upper 60s/near 70F. With mid-upper low exiting and surface trough building in our west we should see WAA through the day Monday. This will support highs in the 90s, with a few locations possibly reaching the 95-98 range assuming good clearing/mixing. .LONG TERM...(Monday night through Sunday) Issued at 204 PM MDT Sun Jul 16 2017 Monday night-Tuesday: Shortwave transverses the area bringing a chance of showers and storms Monday evening and overnight. Ridging aloft begins to build as high height center will be over the area. May see a few pop up showers over northern portions of the area Tuesday afternoon. Highs will be above normal with most locales in the upper 90s and low 100s. Wednesday-Thursday: Upper level ridging dominates the weather through the period. Models in good agreement that these two days will be the hottest of the week. Heat indices will be near or above 105F for areas east of Highway 83. May see a few storms develop over parts of our CO counties during the late afternoon to early evening on Thursday. Friday-Sunday: Models are not in particular good agreement for this coming weekend. Upper level ridging begins to progress to the east of the CWA on Friday. Zonal flow follows on Saturday. Looks as though there will be a chance of rain each day. GFS is advertising a similar setup as the one that has affected the CWA the past few days, with an upper low meandering towards the area from CO on Sunday bringing good chances of rain and plenty of cloud cover. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 519 PM MDT Sun Jul 16 2017 VFR conditions forecast for the TAFs. Main focus will be the timing of storms that will move over KGLD this evening. Based on how well the model data has performed the last two nights, am not too confident with the exact timing of the rainfall for KGLD. Based on latest data, am confident rainfall will be over the site during the latter half of the evening, but confidence lowers in regard to the begin/end of the rainfall. Any rain that moves overhead will likely be moderate, possibly heavy. KMCK should have rain move over the site in the overnight hours. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...NONE. NE...NONE. && $$ UPDATE...JTL SHORT TERM...DR LONG TERM...SME AVIATION...JTL
Area Forecast Discussion
National Weather Service Green Bay WI
601 PM CDT Sun Jul 16 2017 Updated aviation portion for 00Z TAF issuance .SYNOPSIS... Issued at 228 PM CDT Sun Jul 16 2017 Quiet weather through Monday, then more humid with thunderstorms returning mid-week. The westerlies across southern Canada and the northern CONUS will deamplify and become progressive the next few days. Agreement among the medium range models begins to break down after that, but the pattern will probably trend back to one with a ridge in the west and a trough in the east, though perhaps with less amplitude than we`ve seen recently. The period will begin with seasonably cool air and low humidities, but warmer and more humid conditions will return fairly quickly. Once in place, those conditions are likely to linger for the rest of the period, albeit with some day to day variation. As typical for this time of year, precipitation totals will depend on the movement of individual convective systems. But the overall pattern looks to support enough opportunities for precipitation to result in above normal amounts for the period. && .SHORT TERM...Tonight and Monday Issued at 228 PM CDT Sun Jul 16 2017 The latest RAP analysis and satellite/radar imagery show high pressure centered over Lake Superior early this afternoon. Very dry air is associated with the high, with pwats falling to 0.5 inches. As a result, skies have been gradually clearing from north to south today, though scattered to broken ceilings are hanging on over central and east-central WI. There too, skies should turn mostly clear by the end of the afternoon. As high pressure slides south into the area, temps and fog potential are the main forecast concerns. Quiet weather is expected over the next 24 hours, thanks to high pressure building southward across the central Great Lakes. Very dry mid-level air beneath the ridge axis will accompany the high, leading to mostly clear conditions over the period. As winds fall off tonight, some potential for ground fog formation after midnight due to min temps projected to fall below the cross-over temp. Statistical guidance is not bullish on fog potential, so kept the patchy wording over the sandy soil areas, like the previous forecast showed. Cool lows tonight ranging from the mid 40s to mid 50s. Highs will be several degrees warmer than todays readings, and range from the mid to upper 70s. .LONG TERM...Monday Night Through Sunday Issued at 228 PM CDT Sun Jul 16 2017 Though models differ on the details, there is likely to be a round of convection as a frontal boundary crosses the area sometime around Tuesday night. That will probably be followed by a lull in the rain chances, though by then the models were sufficiently different that the blend of guidance used to initialize the forecast ended up with chance/slight chance PoPs for at least a portion of the area. Additional rain chances will occur during the remainder of the forecast as shortwaves in the flat upper flow interact with the frontal zone to our south. The front appears to be far enough south so that the heaviest rain and greatest flooding potential will remain south of the area, but that will certainly need to be watched closely in the coming days. No significant chances were made the forecast initialization generated from a broad-based blend of guidance products. && .AVIATION...for 00Z TAF Issuance Issued at 601 PM CDT Sun Jul 16 2017 Mostly clear skies and light winds have settled in across the TAF sites as high pressure builds in across the region. These conditions are expected to last through Monday. The one main issue could be ground fog formation late tonight into early Monday morning. MOS guidance does not support much in the way of fog, therefore will maintain the patchy mention of fog over the sandy soil areas of northern Wisconsin with this issuance. && .MARINE... Issued at 228 PM CDT Sun Jul 16 2017 Winds and waves are both marginal for the small craft advisory this afternoon. With a few gusts still occurring above 20 kts and Minneapolis Shoal light around 25 kts, will keep the advisory and beach hazard statement going into the evening. Most gusts should remain at least into the 15-20 kts range through midnight. && .GRB WATCHES/WARNINGS/ADVISORIES... Beach Hazards Statement until 10 PM CDT this evening for WIZ050. && $$ SYNOPSIS.......Skowronski SHORT TERM.....MPC LONG TERM......Skowronski AVIATION.......Kurimski MARINE.........MPC
Area Forecast Discussion
National Weather Service North Platte NE
657 PM CDT Sun Jul 16 2017 .SYNOPSIS... Issued at 306 PM CDT Sun Jul 16 2017 A closed upper low was analyzed in east central Colorado at 20z. Thunderstorm activity still at a minimum with only isolated storms from extreme east central Colorado into extreme southwest Nebraska. A rather large cumulus field however across the region. Valentine has once again reached 100 degrees as of 20z. This is the third day in a row, and the 7th time this month Valentine has reached or exceeded 100. Valentine is also been very dry so far this month with 0.10 recorded on July 3rd, and only a trace on two other occasions, attributing to the heat. && .SHORT TERM...(This evening through Monday) Issued at 306 PM CDT Sun Jul 16 2017 Tonight...A closed low center over the CO-NE-KS border will lift slowly into southwest Nebraska overnight. This will bring increasing chances for showers and thunderstorms to southwest Nebraska. The RAP and HRRR model both indicate precipitable water values increasing to 1.5-1.75 inches, which is overdone slightly, but indicates the anomalously high moisture available. Winds at 850 mb increase to 30 kts and as Shown by the NAM bufkit, deep warm rain processes indicate to potential for heavy rainfall developing late tonight. On Monday, this closed low will be the main weather feature, with abundant moisture and chances for precipitation up to 50 percent from southwest into central Nebraska thorough the day. The NAM remains slightly faster with this system than the GFS, and accounted for a slower solution. Given the model QPF output, locally heavy rainfall is suggested. Abundant cloud cover from southwest through central Nebraska will also hold back highs to the upper 80s. To the west and north, highs will reach the low to mid 90s. greater instability to also support isolated storm development across northern Nebraska in the afternoon. Much of western Nebraska will be in a marginal risk area, with marginally severe hail and wind gusts possible. .LONG TERM...(Monday night through Sunday) Issued at 306 PM CDT Sun Jul 16 2017 The closed low will become an open wave as it moves into eastern Nebraska overnight. Still a good chance for thunderstorms across the eastern zones Monday evening. Other thunderstorms are likely to develop in the panhandle and southwestern South Dakota and move into the northwest Sandhills as well. Heating back up Tuesday, as the upper ridge oriented west to east from the Four Corners through the Central Plains bring highs back into the mid and upper 90s. A weak front to bisect the area Tuesday afternoon and evening for a focus for thunderstorms to develop on with stronger winds aloft in place across the Northern Plains. There will again be a marginal risk area, north of I80, where marginally severe hail and wind gusts are possible. Wednesday shaping up to be the hottest day of the week, as the upper ridge intensifies across the Central Plains, and the frontal boundary lifts north into South Dakota. Most area are likely to reach 100 degrees, with southwest Nebraska into the central sandhills reaching as hot as 105. A chance for thunderstorms Wednesday evening across north central Nebraska, which will be on southern periphery of the upper ridge. There will chances for thunderstorms over portions of the forecast area each day Thursday through Sunday. The main upper ridge will migrate into the Southern Plains and southeastern U.S., and bring monsoonal moisture into the region. The northern stream will become more active, and bring better chances for thunderstorms late afternoon and overnight each day. Highs to remain above normal Thursday and Friday from 92 to near 100 degrees, then lower 90s Saturday, and upper 80s by next Sunday. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 656 PM CDT Sun Jul 16 2017 For the KLBF terminal, expect partly to mostly cloudy skies overnight as a weak upper level disturbance lifts slowly east into southwest Nebraska. Light rain showers with embedded thunderstorms will be possible late Monday morning into the afternoon hours. With isolated coverage expected and some timing differences within the models will handle the mention of tsra with a vcts group. For the KVTN terminal, expect clear skies mainly with some few to scattered high clouds developing overnight over northern Nebraska. Cloudiness should persist into Monday with scattered clouds at 20000 FT AGL. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Roberg SHORT TERM...Roberg LONG TERM...Roberg AVIATION...Buttler
Area Forecast Discussion
National Weather Service Omaha/Valley NE
603 PM CDT Sun Jul 16 2017 .SHORT TERM...(Tonight through Wednesday) Issued at 330 PM CDT Sun Jul 16 2017 The main forecast issues in the short term will be chance for thunderstorms...temperatures...and heat headlines. The latest surface map had temperatures again in the 90s with a weak surface boundary near Norfolk to Harlan where readings were closer to 90. Heat index values are mostly 95 to 100...however local conditions has them variable with some high and some lower. Visible satellite imagery had a few cumulus in our area with a few thunderstorms in southeast Iowa and west central Iowa closer to where a shortwave is passing through the region. WSR-88D radar reflectivity shows thunderstorms in the upslope region in northeast CO and near Ottumwa and southeast Iowa. The main storm track for the short term will be over the Northern Plains, however a pesky area of low pressure in the mid levels currently over eastern Colorado is forecast to drift eastward during that time. Water vapor satellite imagery does a nice job depicting the ridging across the central U.S. into Canada and shows the moisture over parts of the southwest U.S. into CO/western Kansas. The 12Z OAX sounding this morning had 1.13 PWAT. PWAT values in a narrow area into to 1.25" then drop for Monday ahead of the moisture with the pesky low. The RAP has been overdoing the precip today and the HRRR/RAP try to build echoes back toward southwest Iowa late this afternoon. The satellite shows a few cumulus from Pottawattamie Co. eastward and could see something isolated develop. For now will leave dry and pass on to the evening shift to metwatch. As the H5 trough breaks down the ridge over the Northern Plains...the H5 low press drifts into western Nebraska Monday morning and central/parts of northeast and east central Nebraska Monday afternoon. Outside of the clouds...southwest flow and very warm h85 temperatures should keep highs in the 90s. Isolated thunderstorm chances will spread into northeast Nebraska by 00Z with chance pops overnight for all but southeast Nebraska and southwest Iowa. Rain chances linger for Tuesday and Tuesday night, however the coverage appears better to the north of the area. The lingering clouds could hold temperatures back, however with the main front still to the north...have highs again in the 90s. Hot temperatures return for Wednesday and highest heat index values from 100 to 110. Considered an excessive heat watch, however with isolated to scattered showers and thunderstorms in the forecast Monday night through Tuesday night and this convective activity could affect boundaries and where the highest heat would be later in the week, decided to hold off. .LONG TERM...(Wednesday night through Sunday) Issued at 330 PM CDT Sun Jul 16 2017 A large area of low pressure is forecast to encompass Hudson Bay with a faster flow across the Northern Plains and a large area of h5 pressure over the central and southern U.S. Hot temperatures are forecast for Thursday and there is still some timing issues related to ripples in the flow across the Northern Plains which is forecast to bring some relief from the heat this weekend along with spotty chances for rain. Highs Thursday and Friday 89 to 100 and 85 to 95 for the weekend. Highest heat index values could range from 100 to 105 Thursday and Friday. && .AVIATION...(For the 00Z TAFS through 00Z Monday evening) Issued at 602 PM CDT Sun Jul 16 2017 VFR conditions are forecast through Monday evening with only scattered high clouds and light southeast to south winds under 10kt. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ SHORT TERM...Zapotocny LONG TERM...Zapotocny AVIATION...Dergan
Area Forecast Discussion
National Weather Service Reno NV
232 PM PDT Sun Jul 16 2017 .Synopsis... Buildups with isolated thunderstorms are expected this afternoon and evening over the eastern Sierra into central Nevada. Low pressure approaching the west coast will increase winds Monday and Tuesday, leading to critical conditions for rapid fire spread. Decreased winds with hot temperatures are forecast for the balance of next week, with isolated storms confined to mountain areas. && .Discussion... * Thunderstorm Trends: Isolated storms remain in the forecast through this evening following latest HRRR guidance. Satellite showing decent buildups over higher terrain from Alpine Co south and eastward into central Nevada. This is the area we`re watching for possible storms. No severe nor flash flood storms expected but new fire starts from lightning and strong outflow winds are possible. Airmass dries out and stabilizes starting Monday as southwest flow aloft increases. This should push storm chances out of our region through at least Wednesday. * Radar Status: The Reno KRGX radar is inoperative until further notice. An apparent motor failure is being investigated by technicians this afternoon. We`ll hopefully have a better handle on when the radar will return to service then. Use of surrounding radars such as Sacramento or Elko may help but details won`t be as clear over our region. GOES-16 data and lightning networks will prove useful for storm monitoring this afternoon. * Increased Winds Monday, Tuesday: Low pressure off the Pac NW will yield increased southwest flow aloft and stronger than normal mid-summer winds early this week. While not terribly impactful for travel, this could be a big scenario for fire. See fire weather section for more details. Choppy waters will be encountered on most area lakes, so Lake Wind Advisories will be posted for Monday. * Storm Trends Late Week: High pressure will build back over the region bringing generally quiet and hot weather through next weekend. But not excessively hot. Isolated storms could return to the Eastern Sierra starting Thursday afternoon. GEFS/ECMWF simulations continue to suggest a big monsoon moisture push into our region early-mid next week. This would result in more widespread thunderstorms and a possible flash flood scenario, something we haven`t seen much of so far this summer. Confidence remains mixed but worth monitoring. -Chris && .Aviation... * Areas of haze and smoke from Long Valley fire earlier resulted in MVFR visibilities around RNO and RTS. With now increasing winds and mixing visibilities will steadily improve. Typical afternoon and evening westerly winds today will transition to northwest overnight. This could lead to smoke and haze back into RNO/CXP vicinity by daybreak Monday. Surface visibility restrictions should be MVFR at worst with slantwise visibility being poorer. * Isolated storms remain possible this afternoon-evening, mainly for areas south of TVL-CXP-NFL line into the Eastern Sierra (MMH). Based on latest HRRR guidance and satellite trends this looks reasonable. Note that Reno RGX radar is out of service until further notice so radar data over the region will be degraded. * Low pressure approaching Pac NW early this week. Increased west/southwest winds Monday and Tuesday likely to yield some turbulence and localized wind shear. Could impact fire air support ops. Gusts on the order of 30-35 kts likely including RNO/CXP and Long Valley Fire area each afternoon and evening. Not a huge wind event but there will be some bumps. -Chris && .Fire Weather... The forecast remains on track for an extended period of fire weather concerns through about mid-week. Gusty winds and very low RH will combine to create critical fire weather conditions Monday and Tuesday with a more marginal, but non-zero, risk Wednesday. Monday`s conditions continue to pose the largest concerns with a projected 9-12 hour period of critical fire weather conditions. A trough dropping out of the Pacific Northwest will strengthen the wind field with gusts expected in the 30-40 mph range. Winds linger into the overnight hours especially along upper slopes and ridges. A significant dry slot will also accompanying this trough resulting in lower than usual afternoon humidity, 4-10% in western Nevada, and abysmal overnight recoveries. Downwind of existing wildfires, like the Long Valley and MM155 fires, Sutcliffe and Grass Valley south of Winnemucca are in a higher threat area. This is a particularly dangerous situation where fire spread rates may greatly exceed fire protection ability. You may have very little time to leave, so it is best to heed any evacuation orders. Winds increase again Tuesday afternoon to a slightly lesser degree, gusts 25-35 mph, as the pressure gradient remains relatively tight. Hours under red flag conditions decreases from Monday to 3-7 hours Tuesday. As such, the Fire Weather Watch has been upgraded to a Red Flag Warning. Any active fires will intensify once again reducing the effectiveness of fire suppression measures. Winds Wednesday have been subtly increasing each new model run. Concerns are increasing, but no watches or warnings have been issued yet. Some of the higher slopes and ridges will briefly meet critical thresholds, but the duration is currently projected to be only around a couple of hours. Overall, conditions are expected to be more marginal. However, as we have seen this season, fires involving grasses and sage will be very active even in marginal conditions. Finally, smoke and haze around the Reno Metro area has been reducing Air Quality during the overnight and morning hours beneath nocturnal inversions. Recent readings in Reno have shown that air quality has degraded into the "Unhealthy for Sensitive Groups" rating. Locations closer to active fires, like Palomino Valley and Pyramid Lake, will have worse conditions. As long as fires are burning in close proximity to Reno and other populated areas, expect poor to moderate air quality. Boyd && .REV Watches/Warnings/Advisories... NV...Red Flag Warning from noon to 8 PM PDT Monday NVZ450-453-458-459. Red Flag Warning from noon to 8 PM PDT Tuesday NVZ450-453-458-459. Lake Wind Advisory from noon to 8 PM PDT Monday NVZ002>004. CA...Red Flag Warning from noon to 8 PM PDT Monday CAZ270-271-278. Red Flag Warning from noon to 8 PM PDT Tuesday CAZ270-271-278. Lake Wind Advisory from noon to 8 PM PDT Monday CAZ071>073. && $$ For more information from the National Weather Service visit...
Area Forecast Discussion
National Weather Service Tallahassee FL
802 PM EDT Sun Jul 16 2017 .UPDATE... We saw an early start and early exit of widespread convection across our CWA today. Only very light patches of rain remain so will leave low PoPs up until 06z. Thereafter, we could see convection moving in from the west across the Florida Panhandle prior to daybreak. Otherwise, mostly cloudy overnight with lows in the lower 70s. && .PREV DISCUSSION [729 PM EDT]... .NEAR TERM [Through Tonight]... Scattered to numerous showers and thunderstorms will continue into the early evening hours and then gradually diminish. A few strong to marginally severe storms cannot be ruled out given decent mid-level lapse rates and strong instability, mainly across the northern and eastern halves of the area which haven`t been worked over yet with prior convection. Late tonight, a decent chunk of the CAM guidance indicates some redevelopment of convection along the panhandle coast. The HRRR has been very persistent in showing this scenario through at least its 16z run today. If this scenario were to pan out, then localized heavy rain could be a threat along the panhandle coast late tonight into Monday morning with PWATs near 2 inches and weak steering flow. This will be something to keep an eye on in the model guidance during the evening hours. Overnight lows will generally be in the low to mid 70s across the area. .SHORT TERM [Monday Through Tuesday Night]... Mid and upper level troughing over the eastern CONUS today will deepen, extending south into our local area. With deep layer southwest flow, our already juicy atmospheric column will see an increase in deep layer moisture. Model PWATs climb above 2" across our area Monday. A stalled frontal boundary over northern MS/AL/GA will be dragged southward as the mid/upper level trough deepens into the southeastern CONUS. This forcing, along with diurnal heating which will increase instability and help initiate a seabreeze, will be plenty to initiate convection tomorrow. Expect scattered to numerous storms across the area, similar to today. With rich Gulf moisture in place and moderate instability, some of these storms could produce heavy rain and gusty winds. On Tuesday, the trough will lift northeastward, moving the front further away from our area. The greatest chances for storms on Tuesday will be in south central GA and the eastern FL Big Bend. Overall moisture will be decreasing, but heavy rainfall and gusty winds will still be possible. .LONG TERM [Wednesday Through Sunday]... The mid and upper level trough will continue to lift northeastward, allowing ridging to build in aloft. Daily chances for scattered afternoon thunderstorms remain in the forecast through the weekend, though storms are expected to be mostly focusing over north FL. Highs will be in the low to mid 90s and lows will be in the low to mid 70s. .AVIATION [Through 00Z Tuesday]... VFR conditions are expected outside of thunderstorms. However patchy fog is possible in the late night/early morning hours. Any fog will likely be MVFR and a temporary condition. Showers and thunderstorms will be widespread on Monday and will likely start early again. Showers and thunderstorms will move inland from the Gulf starting in the early morning at ECP. By late morning activity will be increasing near DHN and TLH. ABY and VLD will see increasing activity by early afternoon. Winds will be mainly light with gusty winds possible in and near thunderstorms. .MARINE... Outside of daily chances for showers and thunderstorms, winds will be around 10 knots or less through the week. Seas will be low as well, 2 feet or less through the period. .FIRE WEATHER... Wet conditions continue for most of the region. Dispersion indices will be low on Monday, under 20 during the daytime in parts of SE Alabama and SW Georgia. .HYDROLOGY... A disturbed pattern will remain in place early this week, causing an increase in chances for showers and thunderstorms through Tuesday. While widespread rainfall accumulations are expected to fall around the 1 to 2 inch range, there is the potential for 3 day totals closer to 4 to 6 inches. At this time, rivers are low enough to not warrant concern for river flooding from this heavy rain, but localized flooding will be possible for the next few days. && .PRELIMINARY POINT TEMPS/POPS... Tallahassee 73 87 74 89 74 / 20 60 20 60 20 Panama City 77 85 76 86 77 / 50 60 30 50 20 Dothan 72 86 73 88 73 / 30 60 20 50 20 Albany 72 88 73 89 73 / 30 60 30 50 30 Valdosta 72 89 73 91 73 / 30 70 30 70 20 Cross City 73 89 73 91 73 / 20 50 20 40 20 Apalachicola 76 85 76 87 76 / 30 40 30 50 20 && .TAE WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AL...None. GM...None. && $$ UPDATE...Barry NEAR TERM...DVD SHORT TERM...Moore LONG TERM...Moore AVIATION...McDermott MARINE...Moore FIRE WEATHER...McDermott HYDROLOGY...Moore
Area Forecast Discussion
National Weather Service Tucson AZ
824 PM MST Sun Jul 16 2017 .SYNOPSIS...Expect scattered to numerous thunderstorms through the evening and overnight hours...followed by widespread showers with embedded thunderstorms Monday. Heavy rainfall will occur with the stronger thunderstorms. Isolated to scattered mainly afternoon and evening thunderstorms will then prevail Tuesday into next weekend. && .DISCUSSION... Another complicated forecast for this evening as earlier convection was rather scattered/disorganized in nature, save for the few storms that caused damage on the west side of Tucson around 5 pm. Most storms managed to die off around 7pm but there has been quite a bit of new development across the area just within the past few minutes. A massive complex continues to dive southward out of Coconino and Yavapai Co`s with other complexes forming over Pinal/Graham/Greenlee Co`s. This is well forecast by the HRRR, UA WRFs, and the HRRRx with nearly all CAM`s indicating the show is only beginning at this point. Nearly all models show converging complexes this evening but the big question is will this cluster move through Tucson, or perhaps stay to the northwest. Conflicting signals in the models but at this point it appears the HRRR may be a bit too far east with its solution based on current radar trends. Correcting for this would take the bulk of any new activity west of Tucson but that`s hardly to say that Tucson is in the clear. PoPs have been raised in nearly all locations overnight. Regardless of where cell mergers take place, PSR and TWC 00Z soundings reveal a considerable amount of instability above 600- 700mb. BL below those levels appear to be relatively stable but these soundings are more than suggestive of long lived storms due to elevated instability through much of the night. Suffice to say the Flash Flood Watch will remain in effect untouched as hydro concerns will be front and center for the rest of the night. && .AVIATION...Valid thru 18/06Z. Bit of a break this evening but additional TSRA/SHRA expected late tonight into early Monday morning. Storms shouldn`t be severe but will be heavy rainers with brief periods of MVFR or even IFR cigs/vsbys possible. A bit of a break around daybreak but conditions will deteriorate once again Monday afternoon. Otherwise, VFR conditions with surface wind variable in direction mainly less than 12 kts. Aviation discussion not updated for TAF amendments. && .FIRE WEATHER...Scattered to numerous showers and thunderstorms mainly during the afternoon and evening hours through Tuesday. Somewhat less coverage of thunderstorms should occur west of Tucson later this week. However, ample moisture will still produce isolated thunderstorms west of Tucson with scattered thunderstorms from Tucson eastward Wednesday into next weekend. Daytime temperatures will be at least a few degrees below seasonal normals this week. && .PREV DISCUSSION... Starting up nicely today with fat juicy storms. Watch for potential underestimation of precip by radar. Another outflow trying to push southwest out of the Rim country, but heavy precip is shaping up as our biggest concern. Plenty of moisture, a decent easterly component to our flow, and the proximity of a weak inverted trough immediately east and southeast of the area will continue this busy thunderstorm period. Precipitable water ranging from 1.45 to 1.7 inches across the area with surface dew points in the mid to upper 60s. The 12Z KTWC sounding showed plenty of conditional instability and favorable conditions for strong outflows from the northeast and east. We will continue to be vulnerable to organized thunderstorm activity from afternoon to late evening hours. With the proximity of the inverted trough and weak easterly impulses combined with a steady flow, we will also tend to reload the atmosphere more quickly than usual between event periods. Flash Flood Watch through Monday evening, and another day with marginal severe from SPC looks good. Monday looks like a good chance of precip, but with the strong potential for another overnight period, and possibly extending into the morning hours, what form will it take? Right now the bet is for scattered showers with embedded thunderstorms and a continued heavy rain threat. We could reset once again for another solid thunderstorm day though. Depending on timing of activity over the next 36 hours, Tuesday could be down as we work through what`s left of the inverted trough. Beyond that, it doesn`t really look like it`s going to let up, with high pressure in a favorable position to continue to allow a deep fetch of moisture into the area along with keeping things open for easterly wave activity. && .TWC WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through Monday evening for AZZ501>515. && $$ Leins/Meyer/Zell Visit us on Facebook...Twitter...YouTube...and at
Area Forecast Discussion
National Weather Service Las Vegas NV
855 PM PDT Sun Jul 16 2017 .SYNOPSIS...Isolated to scattered thunderstorm activity can be expected the next several afternoons particularly across Southern Nevada and Northwest Arizona, with temperatures gradually cooling to near seasonal normals. By Tuesday evening, deeper moisture will begin to push in with widespread clouds and showers possible Wednesday. Moisture looks to linger through the weekend with near daily thunderstorm chances and slightly above normal temperatures. && .UPDATE...Convection still holding together across portions of Lincoln, Clark and Mohave Counties this evening as forecast. Due to outflow boundary interactions, I hesitate to remove mention of thunderstorms in any particular area for the rest of the evening and no updates are planned. - Harrison- && .PREV DISCUSSION... 210 PM PDT Sun Jul 16 2017 .SHORT TERM...thru Tuesday Night. Moisture surge last night has worked to subdue the afternoon temperatures rise this afternoon with current temperatures across the region running between 4 and 6 degrees cooler than this time yesterday but dewpoints 12-18 degrees higher...particuarly from Las Vegas east. Thus far, thunderstorm development has remained isolated and terrain driven but a few more degrees of heating should spark a marked increase in development later this afternoon. In fact, SPC mesoanalysis suggests over 1500 J/Kg of CAPE across most of Clark and Mohave counties, which would suggest potential for some intense updrafts and rapid storm development once that instability can be realized. The HRRR has been fairly consistent indicating isolated to scattered storms across Clark county this afternoon, with more robust activity across Mohave county. Will also need to watch activity in SW Utah as it may congeal and push south late this evening into eastern Clark and northern Mohave counties. Overall, I expect a relatively active evening across the region with things tapering off late this evening. Similar conditions will be in play tomorrow, so I expect a general repeat of things today. On Tuesday, forecast soundings illustrate some warm air aloft moving in which may suppress activity during the day, however, an inverted trough moving in midweek will begin to make its approach Tuesday night with a substancial increase in moisture content moving in. This may result in a complex of nocturnal storms along the leading edge of this gradient, or it may work in more gradually in the form of light showers and clouds. Either way, low PoPs were continued through the nighttime hours Tuesday night ahead of this moisture increase. && .LONG TERM...Wednesday through Saturday. A little better run to run consistency this morning, although model to model consistency still isn`t the best. Forecast confidence is about average. The main focus is on Wednesday, as the models still agree to some extent on an inverted trough rolling west across the Gulf of California on Tuesday, eroding the western extent of the ridge and sending a push of moisture into the region on Wednesday. This should result in an increase in PoPs and decrease in temperatures, at least for the eastern half or so of the area (and possibly farther west depending on exactly how the details evolve). Confidence is lower for Thursday through Saturday, but there should be enough moisture available for thunderstorm chances each day, at least for areas near and east of Las Vegas. A bigger question is whether the clouds and storms will keep temperatures down or whether there will be enough breaks of sunshine to allow for a rebound. MOS guidance has trended down quite a bit for those days, and nudged the forecast in that direction. These cooler temperatures may also suppress thunderstorm development Wednesday and result in more gloom than boom. && .AVIATION...For McCarran...Southeasterly winds this afternoon will shift to the southwest this evening and tonight remaining around 10 knots or less. Isolated showers and storms cannot be ruled out around KLAS this evening and Monday afternoon/evening but confidence is low in this activity directly affecting the terminal so have not included in current TAF package. More than likely brief erratic wind shifts and gusts will be possible as outflow boundaries move through the valley during these times. Light and variable winds Monday morning will increase once again out of the south to southwest throughout the afternoon remaining primarily between 10-15 knots through Monday night. For the rest of southern Nevada, northwest Arizona and southeast California...South to southwest flow will prevail across much of the area today and tomorrow with gusty winds of 20-25 knots possible along the Colorado River Valley each day. Highest coverage of showers and storms today and tomorrow will be across Mohave, Lincoln, and Clark counties, especially across the higher elevations. Monday will see chances for isolated showers and storms spreading westward into San Bernardino, Nye, and Inyo counties. Any shower/rain activity could create gusty erratic winds and heavy downpours. This increase in moisture will also bring increasing mid/high cloud cover across a majority of the area. && .FIRE WEATHER...Increased moisture will result in isolated to scattered thunderstorm activity for the next few afternoons especially across southern Nevada and Northwest Arizona. On Tuesday evening...clouds and moisture levels will increase further with widespread showers and abundant clouds expected Tuesday night and Wednesday across Northwest Arizona and Southern Nevada. Drier conditions are expected further west across the Sierra and Western Mojave desert but isolated storms will remain possible. Temperatures will be gradually cooling through the week...with the coolest day looking like Wednesday. && .HYDROLOGY...Creeks, streams and rivers in northern Inyo County continue to run high and fast from snow melt. Some road closures continue in the area. Bishop Creek Bypass and Big Pine Creek Bypass continue to be utilized to minimize flows through Bishop and Big Pine. Isolated thunderstorms over the mountains may aid snowmelt runoff and keep some drainages elevated over the coming days as well. Remember, never drive through flooded roadways or around barricades. Also, pastureland or farmland adjacent to creeks, streams or rivers could experience areas of standing water. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM/FIRE WEATHER...Outler LONG TERM...Morgan/Outler AVIATION...Guillet For more forecast information...see us on our webpage: or follow us on Facebook and Twitter