Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/25/20

Area Forecast Discussion
National Weather Service Bismarck ND
1013 PM CDT Wed Jun 24 2020 .UPDATE... Issued at 1007 PM CDT Wed Jun 24 2020 Scattered thunderstorms continue across north central North Dakota and will slowly move southeast overnight. Storms are producing frequent lightning and gusty winds around 40 mph, but remain well below severe limits. Lowered precipiation chances tomorrow with this update as the last trends in guidance indicate less robust thunderstorm develop along the front until the afternoon hours. By then the front will be across east central ND and thunderstorms will quickly move east and out of the area by the late evening. UPDATE Issued at 623 PM CDT Wed Jun 24 2020 An isolated thunderstorm continues to trek slowly across central ND this evening. A very weak and narrow band of low-level convergence is likely supporting the development and maintenance of this storm. Further northwest a complex of storms is riding along the nose of a thermal ridge. This complex will impact northern North Dakota through the evening hours and should slowly dive south into the James River Valley overnight. Capping and the time of day should limit the threat for severe storms, but gusty winds and small hail can`t be ruled out with any storm this evening and overnight. && .SHORT TERM...(This evening through Thursday) Issued at 223 PM CDT Wed Jun 24 2020 This afternoon, low pressure and an associated cold front in south central Saskatchewan is forecast to move east to Manitoba by Thursday afternoon. The cold front will be the focus for scattered thunderstorms tonight and Thursday. The latest HRRR tracks a line of convection from the Sask/Mant border south into northwest ND this evening and then southeast from there into the Devils lake basin and the northern James River Valley after midnight. This looks fairly reasonable. This initial convection is not expected to be severe. On Thursday, expectations are thunderstorms will redevelop by mid afternoon along the cold front across eastern ND. While deep-layer shear is not expected to be strong, decent CAPE of 2500 to 3500 will be available for strong updrafts. The are of concerns will be the southern James river Valley in the mid to late afternoon and the evening hours. Hail to Ping pong ball and wind gusts to 60 mph would be possible. .LONG TERM...(Thursday night through Wednesday) Issued at 223 PM CDT Wed Jun 24 2020 The extended forecast will feature a more active thunderstorm pattern, beginning Sunday, as a cold h500 upper low will become the dominant feature across the northwest US with downstream ridging over the western Great lakes into the central Plains. This pattern would favor a moist flow into the northern plains with southwest flow aloft, veering winds with height and short wave energy to provide lift. We do discount the 12Z GFS in the Tuesday-Wednesday time period as it clearly has some convective feedback that causes the model to generate an anomalous upper low over the Dakotas. We prefer the European model projections which maintain the upper low over the northwest US and southwest flown aloft. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 623 PM CDT Wed Jun 24 2020 VFR at all TAF sites through the TAF period unless impacted by a thunderstorm. Some isolated thunderstorms are possible tonight across northern and portions of east central North Dakota and could impact KXWA/KMOT/KJMS. A cold front will swing through the state from west to east tomorrow and will be the focus for scattered showers and thunderstorms. Every terminal has the potential to see precipitation tomorrow, but due to the uncertainty in coverage, little more than a vicinity mention was added at this time. && .BIS WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...AJ SHORT TERM...waa LONG TERM...waa AVIATION...AJ
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
648 PM CDT Wed Jun 24 2020 .DISCUSSION...Updated for latest aviation discussion below. && .AVIATION...Brownsville radar and surface observations indicate an outflow boundary moving southward through the Rio Grande Valley. As a result, winds have briefly shifted to the north-northeast at MFE and HRL. Also, can`t rule out convection developing along the boundary and will continue to the mention VCTS/TSRA through late this evening. Activity diminishes late tonight before another round of convection develops Thursday morning. Will add a PROB30 group for all aerodromes for MVFR conditions in TSRA mainly after 16Z. && .PREV DISCUSSION... /issued 311 PM CDT Wed Jun 24 2020/ SHORT TERM (Now through Thursday): A weak cold front continues to slowly move across South Texas and is located just north of Hebbronville and Falfurrias. With weakly unstable flow aloft and little to no capping, convection has gradually increased ahead of the boundary. Strong instability is noted in environmental mesoanalysis data with MLCAPE on the order of 3000 to 3500 J/kg. Shear remains fairly weak, but a few isolated severe storms will be possible. The main threats will be damaging wind gusts, but large hail of up to quarter-size will also be possible. High-resolution CAMs, including the latest HRRR and the 12Z ARW, show very heavy rainfall by this evening, with some clustering moving into the Rio Grande Valley. With slow-moving storms and above-normal precipitable water content, 2-inch per hour rainfall rates will be possible, leading to localized flash flooding. In collaboration with the Weather Prediction Center, they have expanded the marginal risk of excessive rainfall across all of Deep South Texas for this evening. Tonight, conditions should settle down with decreasing convection overnight. The surface front is expected to lift northward on Thursday, but models show a 500mb vort max moving northward and onshore Thursday morning into the afternoon with another round of showers and storms. Locally heavy rainfall will be possible again, so have included such wording in the latest forecast grids. The highest chance for rain will be along the coast and into the Lower Rio Grande Valley. Temperatures should be slightly below normal on Thursday with expected increases in cloud cover and rain chances. Locations in the Upper Valley and northern ranchlands may still reach the upper 90s with most convection holding off until the afternoon. LONG TERM (Friday through Wednesday): The wet and unsettled pattern continues into Friday before the rain chances decrease and temperatures rise this weekend and into early next week. At the start of the long term period, Deep South Texas remains in a general area of weakness between two ridges, with a broad inverted trough cutting north across Mexico and into South Texas. Low level moisture will continue to be transported into the region from Gulf with a strong southerly-southeasterly flow on Friday. Precipitable water values are expected to climb into the 2.00" to 2.30" on Friday. With ample moisture in place, broad troughing and the passing of a vort max will lead to increased rain chances on Friday. Model guidance is now suggesting that rainfall amounts will be greater on Friday than on Thursday. The latest WPC rainfall forecast calls for 0.25 to 1.0 inch of rain on Friday, but pockets of locally higher rainfall amounts are likely as rain rates could climb in excess of 2 inches per hour with any thunderstorms that develop. These thunderstorms will likely be isolated to scattered in coverage, but with a weak steering flow, slow moving storms could increase localized flooding concerns. WPC has included all of Deep South Texas in a marginal risk for excessive rain on Friday, as rainfall amounts could exceed flash flood guidance. Overall, forecast confidence in rainfall amounts is increasing. However, uncertainty is increased slightly due to the arrival of another, greater swath of the Saharan Air Layer (dust) on Friday. This dust could have impacts that the models do not resolve well, such as suppressing convection, or even enhancing it...thus the added uncertainty. Temperatures will be slightly cooler on Friday with the increased convection and cloud cover, but will increase through the weekend and into early next week. Heat indices are expected to reach 105-110 degrees Saturday afternoon and continue each afternoon through early next week. MARINE: Now through Thursday...Winds remain light as the pressure gradient weakens ahead of the cold front. Seas have also been subsiding to around 4 feet across the Gulf waters. Increasing showers and thunderstorms are expected this afternoon and evening, though, so dangerous winds and seas will be possible with any stronger thunderstorms. Another round of thunderstorms will be possible from the south and increasing Thursday morning and afternoon. The gradient is also expected to increase, so a Small Craft Advisory may be needed Thursday afternoon. Friday through Monday...Marine conditions are expected to be slightly adverse to hazardous through much of the long term period. Small Craft Advisories may be needed on Friday as the southeasterly winds strengthen and seas respond, however small craft will need to exercise caution through the weekend and into early next week for hazardous seas and moderate winds. Showers and thunderstorms will be possible over the waters on Thursday and Friday. && .PRELIMINARY POINT TEMPS/POPS... BAYVIEW/PORT ISABEL 77 88 79 89 / 40 60 50 50 BROWNSVILLE 78 89 78 90 / 50 60 50 50 HARLINGEN 76 90 76 89 / 50 60 50 60 MCALLEN 77 92 77 90 / 50 50 40 60 RIO GRANDE CITY 76 95 77 92 / 60 50 40 50 SOUTH PADRE ISLAND 80 85 82 86 / 40 60 50 50 && .BRO WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ This product is also available on the web at: HTTP://WEATHER.GOV/RGV 63
National Weather Service Hastings NE
638 PM CDT Wed Jun 24 2020 .SHORT TERM...(This evening through Thursday Night) Issued at 350 PM CDT Wed Jun 24 2020 Tstm chcs/coverage main issue in the short term. Rest of this Aftn and into Overnight: Current analysis shows pooling moisture along a diffuse warm front running NW to SE from near LBF to HYS. Greatest near-term risk, based on latest vis satellite and comp radar, appears to be along I-70 from GLD to SLN. Another area to watch will be near and N of LBF. Overall feeling is that convection risk to GID CWA is pretty low. While CAPE/shear space is supportive of svr (MLCAPE over 2000 J/kg and 40-50kt of deep layer shear) over W/SW areas, there`s just not much to nudge parcels along as there remains some displacement between most active portion of cyclonic upper flow over upper MS Valley and aforementioned instability axis. Also, motion vectors all are generally NW to SE, so would need development to edge N from central KS to northern KS to pose a risk, or for development w/in CU field over the Sandhills. Latest couple HRRR runs show an iso storm or two w/ the later scenario, but overall likelihood appears low, so only 20-30 PoPs attm from around LXN-Beloit. Thus, svr threat this eve is highly conditional and isolated. Can`t completely rule out some iso elevated convection after midnight given convergence w/ incr low level jet to 40- 45kt and veering in the 06Z-12Z time frame. Nose points to areas near and S of I-80. However, not much upper level support given subtle large scale height rises at H5, and models actually indicate dry air advection in the H7-H85 layer. Hi-res models don`t have any much except near the far SE CWA, so only slgt chc PoPs near HJH. Thu: Main story for Thu is hot/brzy. Warm front that remains from tonight will rapidly shift N Thu AM as lee troughing deepens over the High Plains. This will result in brzy winds. Shortwave ridging/rising heights leads to pretty high confidence in dry conditions for the daytime hrs. H85 temps will rise into the 23-27C range (highest W CWA), which should promote widespread 90s, and perhaps even a run at triple digits at known "hot spots" given ample sunshine. Deep mixing should keep Tds in check, and along w/ brzy winds, it won`t feel terribly humid. Thu night: Chc for rn/tstms along cold front. By Thu eve, a positively tilted trough will extend from Desert SW to ND. An associated SE moving cold front will extend from central SD to a low pressure center near NW Sandhills 21Z Thu, with a diffuse trough/dry line extending S from the low into SW Neb./E CO/W KS. Strong diabatic heating and steep lapse rates in the presence of sfc conv along aforementioned features should be enough to erode CIN and spark tstms late Thu aftn, mainly N/W of the CWA. Question becomes whether or not any of this activity will survive long enough to move into CWA 00Z to 03Z? Models show a strengthening LLJ which may help maintain organization, however, the front will be outrunning the upper trough. Thus, activity will likely encounter warmer mid level temps/incr CIN with SE extent and overall timing is not ideal. This gives me doubt in widespread rn, but some pockets of iso-scat tstms could hold together long enough to give N/W portions of CWA at least some chc for rn. General evolution of 12Z HREF/18Z HRRR seems appropriate, which would place highest chcs from ODX to LXN. Perhaps some of this could be strong w/ gusty winds and marginal hail, but agree w/ latest SPC Day 2 Outlook that greatest svr potential will be N/W of CWA, closer to frontal position at peak heating. .LONG TERM...(Friday through Wednesday) Issued at 350 PM CDT Wed Jun 24 2020 Extended periods look very summer-like, w/ periodic tstm chcs, none of which stand out as "likely", and warm/hot temps. General overview: Models are converging on general solution in that the Day 2 trough will shear out on Fri, w/ N energy rapidly lifting towards Great Lakes, while SW energy gets stuck near Four Corners region and washes out toward Sat. Whatever is left of this energy, if anything, will then get absorbed/ejected in incr SW upper flow ahead of deepening Pac NW trough on Sun. Models remain in good agreement keeping the large scale trough over the Intermountain West Sun-Mon, but then begin to diverge w/ timing and speed of eastward shift Tue-Wed. Nearly every period in the extended has some sort of tstm chcs. However, much like the last couple of weeks, think the official forecast probably looks wetter than what it will be in reality as we`ll be firmly within a summer pattern in which forcing is nebulous, which results in hit and miss pcpn patterns. In theory, the cold front that approaches Thu night and slowly moves thru CWA on Fri could present somewhat better chcs for tstms, but again, upper support is not great amidst neutral or slight height rises. If something were to develop, it looks like S/SE areas would stand best potential given model consensus of bndry position (though confidence on this is not great). Moderate to strong instability would argue for some svr potential, but shear immediately along the bndry is not great (only 25-30kt on avg), so main threats would be pulsey, marginally svr hail and iso downburst winds. What exactly happens to this bndry remains uncertain, but in general, looks like it could hang out just S of the area Sat, then return N Sat night or Sun AM. As such, after briefly "cooler" temps Fri-Sat, have temps warming well into 90s, and maybe some low 100s, for Sun and Mon. Tds will be higher as well, but breezy S winds each day should help offset some of the mugginess. Models ensembles indicate slightly cooler and perhaps a bit more active by middle of next week, but this will depend on progression of western trough, which remains low confidence. && .AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Friday) Issued at 627 PM CDT Wed Jun 24 2020 VFR conditions expected through the period with some passing mid/high level clouds from convection to our west overnight...and clear skies and wind gusts to near 25 KTS out of the south during the afternoon hours Thursday. && .GID WATCHES/WARNINGS/ADVISORIES... NE...NONE. KS...NONE. && $$ SHORT TERM...Thies LONG TERM...Thies AVIATION...Rossi
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
1050 PM EDT Wed Jun 24 2020 .SYNOPSIS... An upper level disturbance will continue to gradually lift over the area today and Thursday, helping produce showers and thunderstorms. Seasonable temperatures will be in store through Thursday before drier air filters in Friday to allow for lower precipitation chances. A noticeable uptick in temperatures occurs through the weekend. Expect the same temperature trend and slightly wetter conditions to enter the region early next week. && .NEAR TERM /THROUGH THURSDAY/... As of 1030 PM EDT Wednesday: An MCV can be seen on area radar mosaic over NW GA driving ENE toward the southern half of the FA. Mainly just light rain within the MCV to affect the FA overnight. The heavier QPF on the NAM and RAP seem to be overdone due to convective feedback. In any case, will keep a chc to low-end likely PoP in the southern portions of the FA. Plenty of mid clouds to continue thru the night, keeping temps mainly in the upper 60s to lower 70s overnight. Min temperatures will be around normal. On Thursday, a stalled front will linger around the FA throughout the day, while aloft, upper troughing will dig through the OH Valley and slowly propagate eastward. Guidance continues to depict better forcing with the upper feature moving through just past the fcst period, but during the afternoon hours, with moisture in place, support from s/w and lingering front will provide instability to warrant the potential for another round of afternoon convection. Max temperatures will fall just short of normal. && .SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/... As of 230 PM Wed: Thursday night the upper-level trough axis moves off to our east as heights rise modestly ahead of shortwave ridging centered over the upper Midwest. The ridge axis will stay to our NW Friday afternoon during peak heating placing our area in a weakly subsident regime. This will be evident by a fairly pronounced 650-700mb warm nose which should cap most convection, especially outside of the mountains. However, a well-mixed boundary-layer combined with typical orographic forcing should overcome the cap in at least a few locations over the mountains, especially south and west. Therefore, slight chance to chance PoPs over the Foothills and mountains prevail with the expectation of at least a few showers and thunderstorms. Ample dry air aloft would support a isolated damaging wind threat if convection can fully tap into MUCAPE of 500-1000 J/kg, but limited CAPE in the hail-growth layer suggests a negligible hail concern and shear does not support organized convection. Model guidance is very unenthusiastic. High temperatures will remain near normal. The low-amplitude shortwave ridge axis will move across the Appalachians Friday night into Saturday morning as a weak remnant trough ejects out of the Lower Mississippi River Valley in response to height falls across the Ohio River Valley. Weak vorticity advection associated with the remnant trough is not expected to overcome slightly worse lapse rates and even lower MUCAPE values Saturday afternoon. Therefore, PoPs reflect slightly lower coverage of showers and storms over the mountains. A frontal boundary draped across the Rust Belt will be too far north to exert much influence over the area outside of an increase in upper-level moisture which will limit DCAPE values for any rogue storm that manages to develop. High temperatures will again be near to slightly above normal. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... As of 200 PM Wednesday: During the beginning portion of the extended forecast period, temperatures will be the topic of discussion as most of the area should be slightly above climo for much of the weekend. Shower and thunderstorm chances will be below climo Saturday into Sunday as warmer air aloft settles in due to a flat upper ridge, which will be the cause of this trend. If any convection develops, most of what forms will stay confined to the higher elevations and that is even a sparse forecast. On Sunday, the upper ridge deepens as it develops over the Mississippi Valley, while a strengthening upper trough begins to dive down into the northeastern CONUS. An omega blocking pattern is evident in both the GFS and ECWMF for the early part of next week. A frontal boundary will likely form across the Ohio Valley and the Mid-Atlantic from this pattern. Shortwave energy below the boundary, along with PWAT values >1.50" for most of the area, should be enough of a spark to allow for convection to form Monday and more widespread Tuesday as the frontal boundary gradually sinks to the south, closer to the cwa. Temperatures should remain around climo through Tuesday as well before the front reaches the region during the middle part of next week. A slight difference between the location and timing from the two global models on the potential stalling from the front, but the overall pattern should remain the same. With plentiful moisture and the frontal boundary possibly becoming quasi-stationary during the middle part of next week, a heavy rain threat and daily convection could be in store for much of the area. && .AVIATION /03Z THURSDAY THROUGH MONDAY/... At KCLT and elsewhere: Convection has waned for the most part, but additional SHRA expected to develop later this evening and patchy - RA thru daybreak Thursday. A large cloud shield spreading across the region will limit fog potential. Some MVFR and even IFR cigs will be possible across northern GA that may spread to KAND. Confidence is too low on whether these cigs will reach KGMU/KGSP. Generally 3500- 5000 ft clouds below a 10000-15000 ft deck tonight thru Thursday morning. Guidance shows an early start to showers and tstms midday Thursday, as a disturbance crosses the area. Winds will be mainly out of the SW across the Piedmont, and NW at KAVL thru the period. Outlook: Drier weather is expected Friday and Saturday, with mainly isolated to scattered aftn/eve convection in the mountains. Low clouds and fog will be possible around daybreak each morning, especially in the mountain valleys. Otherwise expect VFR conditions. Confidence Table... 03-09Z 09-15Z 15-21Z 21-00Z KCLT High 100% High 100% High 100% High 100% KGSP High 100% High 88% High 98% High 100% KAVL High 100% High 86% Med 78% High 100% KHKY High 100% High 100% High 100% High 100% KGMU High 100% High 85% High 100% High 100% KAND High 100% High 90% High 98% High 100% The percentage reflects the number of guidance members agreeing with the scheduled TAF issuance flight rule category. Complete hourly experimental aviation forecast consistency tables are available at the following link: && .GSP WATCHES/WARNINGS/ADVISORIES... GA...None. NC...None. SC...None. && $$ SYNOPSIS...CAC NEAR TERM...ARK/12 SHORT TERM...JMP LONG TERM...CAC AVIATION...ARK
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
1002 PM EDT Wed Jun 24 2020 .SYNOPSIS... Upper level troughing will persist, providing unsettled weather through Thursday evening. Deep layer ridging strengthens Friday, keeping drier conditions in place into the weekend. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... As of 1000 PM Wednesday...Current forecast remain in good shape. No change to this update. Radar returns are showing rain showers located over the SW section of our forecast area will gradually move through, but most of the rain is expected to diminish around midnight. Prev dis...No major changes to the forecast besides delaying the rain that is currently to the SW of the forecast area. The latest HRRR and RAP is showing rain will move into the area within the next hour or so, but diminishing as it moves across the area. Models are showing a brief break from the rain, before it start again after midnight. Prev Dis..Westerly flow coupled with weak subsidence has limited convective initiation this afternoon. Given an area of higher CAPE values near the coast through the next few hours, could still see some isolated showers or storms through early evening and continued with a slight chance PoP through dark. After midnight, axis of mid-level trough starts to move east toward the eastern Carolinas with some decent shortwave energy. This will kick off a few showers and possibly a thunderstorm late tonight into Thursday morning. PoPs increase to 30-40 percent after midnight. With scattered rain around, rain cooled air will allow low temperatures to be slightly cooler than recent morning, in the lower 70s for all areas. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/... As of 345 PM Wednesday...Weak shortwaves embedded in a deep mid-level trough axis will move through the area during Thursday. With a warm and moist environment in place, scattered showers and some thunderstorms are possible. Timing is difficult as the shorter range models show quite a spread in timing, with some showing more precipitation during the morning, while other show a more afternoon event. Most all of our area remains in a Marginal Threat for severe weather tomorrow with strong gusty winds being the main threat. The key will be the degree of destabilization should morning precipitation occur. Regardless, have continued with a 40-50 percent PoP for Thursday. Despite cloud cover, highs should be in the low/mid 80s area-wide Thursday. && .LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/... As of 3 PM Wed...Bermuda High ridging in from the east and inland troughing will persist through the long term period, bringing generally seasonable conditions with day to day variability dependent mainly on upper level synoptic trends. Thursday...Convective activity wanes Thursday night and the loss of daytime heating, and POPs end once the trough axis slides offshore and heights aloft begin to rise late. Friday and Saturday...H5 ridging builds over the area and strong subsidence aloft keeps precip coverage well below normal. Though a stray shower or two immediately along the sea breeze can`t be ruled out either day, the chance is below mentionable levels. Temps near to a couple of degrees above normal both days with ample sunshine. Sunday through Tuesday...Upper level low pressure will cut-off from the background westerlies and drop over the Northeast, with several weak shortwaves traversing the general troughing that will extend over the Carolina Coast. Periods of unsettled weather possible through early next week, with shower/storm coverage not necessarily sticking to the typical diurnal trends, depending on the timing of upper level features. Relatively seasonable airmass prevails at the surface as Bermuda High continues to ridge in the from east with troughing inland, and daily temp trends will be primarily dependent on precip timing and cloud cover. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Short Term /through Tonight/... As of 730 PM Wed...VFR conditions will dominate most of the TAF period, outside of brief sub-VFR conditions due to showers and thunderstorms. Chances of scattered showers and isolated thunderstorms increase ahead of incoming shortwave mainly between 0Z and 3Z with a brief sub- VFR. Afterward VFR conditions are expected into the late morning hours, then there can be MVFR conditions tomorrow afternoon, but confidence is not high as models are not in good agreement as there be additional showers and thunderstorms tomorrow afternoon. SW winds 5kts or less overnight, then becoming 5-10kts tomorrow. Long Term /Thursday Night through Monday/... As of 315 PM Tue...VFR conditions prevail, with any lingering scattered showers/storms Thursday evening the potential for periods of flight restrictions. Friday through the weekend will be drier with VFR expected. && .MARINE... Short Term /Tonight and Thursday/... As of 1000 PM Wednesday...The latest buoy obs are showing mostly SW 5-14 kts and seas 2-4 ft. Wind speeds at 15 knots or less with seas 2-3 feet, with some long period swells over the northern waters. Winds should become SW on all waters later tonight with seas at 2-4 feet. Similar winds are expected for Thursday, but seas may increase a bit to 3-5 feet. Long Term /Thursday Night through Monday/... As of 315 PM Wed...High pressure well offshore and inland troughing will persist through the long term period bringing persistent moderate southwesterly flow, typically a few kts stronger each afternoon than overnight. 3 to 5 ft seas prevail through the period as moderate SSW windswell mixes with small medium period SE swell. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...CTC/BM SHORT TERM...CTC LONG TERM...CB AVIATION...BM/CB/ML/CEB MARINE...CTC/BM/CB/ML
National Weather Service Morristown TN
951 PM EDT Wed Jun 24 2020 .UPDATE... EVENING UPDATE. && .DISCUSSION... Forecast on track this evening with little changes. Slight chance to low-end chance POPs continue for most areas through the night as isolated showers and storms remain possible due to the vicinity of the frontal boundary. Past few runs of the HRRR continue to show this as well. Will send out new zones due to the minor POP adjustments that were made, which was mainly to increase the central valley from slight chance POP to low-end chance POP. SR && .AVIATION... 00Z TAF DISCUSSION. Current VFR conditions will give way to MVFR conditions overnight at all terminals as additional moisture moves into the area. A return to VFR conditions can be expected by tomorrow morning at TYS and TRI and by mid afternoon at CHA. Don`t anticipate any fog overnight due to increasing clouds. SR && .PREV DISCUSSION... /ISSUED 311 PM EDT Wed Jun 24 2020/ SHORT TERM (Tonight through Thursday)... The short term forecast period consists of chances for showers and thunderstorms with slightly below normal temperatures. Strong/severe storms are currently not anticipated within the period. Currently, a surface frontal boundary is located across southern portions of the County Warning Area (CWA) with upper-level troughing across the eastern U.S., generally north of TN/NC. The surface frontal boundary has helped to provide forcing for showers with some embedded thunder across extreme southern portions of the CWA and into northern AL/GA. With the placement of the trough, the CWA is within the right entrance region of a 50+ knot jet streak, which will help to provide upper-level divergence. While the jet dynamics further north help to provide 30+ kts of effective bulk shear, the best instability is much further south, inhibiting chances for severe convection. Chance PoPs were utilized through the afternoon in the southern half of the CWA with this location of the frontal boundary. Increased cloud cover looks to keep temperatures slightly below normal with 80s in most locations being reasonable. Heading into tonight, latest model guidance brings the frontal boundary slightly further north, so slight and chance PoPs were utilized with very isolated thunder chances due to a loss of diurnal instability. Increasing cloud cover from the west will help to keep temperatures somewhat moderated with 60s seeming reasonable given the current setup. For Thursday, surface high pressure will help to provide subsidence and suppress widespread PoP chances. However, isentropic lift indicated by NAM data and steep low-level lapse rates will work to produce isolated convection, mainly over higher terrain and southern portions of the CWA. Temperatures similar to today are expected. BW LONG TERM (Thursday Night through Wednesday)... The upper ridge that`s been dominating the weather pattern the past several days will finally, completely, move out of the area Friday. In it`s place a broad ridge will begin to build in from the west and in response the front that`s been hanging around will lift out of the area. A warming trend can be expected to wrap up the work week with highs reaching back to near normal for this time of year on Saturday. Under this ridging pattern diurnally driven showers and thunderstorms can be expected in the afternoon as moisture continues to be brought up from the Gulf of Mexico. Over the weekend a shortwave is expected to zip across the Ohio Valley and Tennessee Valley, which should bring an uptick in precipitation chances and coverage of showers and thunderstorms that do develop as the surface low and the front push through. Still not super confident on how models are handling the Omega block next week, especially with how poorly they`ve done with this initial trough over the area. But there`s indications that a cut off low will traverse back down from the northeast towards the area. Am going to continue going slightly lower on PoPs than what the NBM model guidance outputs for the end of the 7-day forecast as in these situations it tends to overdo the precipitation chances. ABM && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 67 83 68 86 69 / 40 30 30 50 20 Knoxville McGhee Tyson Airport, TN 66 82 65 87 68 / 30 20 10 30 20 Oak Ridge, TN 65 82 65 86 67 / 30 20 10 30 20 Tri Cities Airport, TN 62 80 61 84 65 / 20 20 10 20 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$
Area Forecast Discussion
National Weather Service Las Vegas NV
843 PM PDT Wed Jun 24 2020 .SYNOPSIS...Hot, above average temperatures are expected to continue through the remainder of the week and going into the weekend. Isolated showers and thunderstorms possible this afternoon over the Sierra, expanding to portions of the southern Great Basin on Thursday. The end of the weekend into the start of the next work week, a potent trough will bring a drop in temperatures and gusty winds. && .UPDATE...No update necessary for the rest of tonight or Thursday. Similar to yesterday, we observed only a few thunderstorms develop over Inyo and Esmeralda County. More impressive storms were again to the north across western/northern Nevada closer in proximity to shortwave trough. That shortwave trough is progged to shift southeast across central Nevada during peak heating Thursday afternoon. With just a few degrees of cooling aloft tomorrow the steepening lapse rates will generate a more unstable air mass for greater coverage in thunderstorms. Concern with storms tomorrow will be gusty winds as early afternoon forecast soundings at Bishop and Tonopah both indicate invert-v profiles. Of course, some locally heavy rain and hail will occur with more impressive updrafts. && .SHORT TERM...Today through Saturday. Above average temperatures, warm overnight lows and breezy afternoons continue this week as the ridge of high pressure over the Baja continues. Daytime heating has resulted in a few diurnal thunderstorms across north and central Nevada as well as portions of the northern Sierra. The HRRR indicated the formation of a few cells over our portion of the southern Sierra in Inyo County today. Watching a few radar returns come to fruition over Inyo County this afternoon - particularly just south of Bishop - though these returns are without lightning strikes for the time being. The chance of isolated thunderstorms along portions of the Sierra as well as Esmeralda County lasts through the remainder of the afternoon and into the evening hours. This week, we have mentioned the potential for a trough to drop down and potentially hinder our heat-causing area of high pressure. With each model run, this trough has weakened, which is now forecast to be a shortwave area of low pressure. This disturbance will pass through the Desert Southwest Thursday, which will elevate afternoon breezes and drop temperatures by a couple of degrees. The primary impact of this disturbance, though, will be the arrival of a relatively moist weak cold front. This cold front will materialize in the form of isolated showers and thunderstorms again Thursday afternoon over portions of the southern Sierra and the southern Great Basin. Highest chances will be through the afternoon and early evening, stretching across much of Inyo, Esmeralda, Nye and Lincoln counties, though slight chances reach as far south as the higher elevations of Clark and Mohave counties as well. Not much is expected in the way of measurable rainfall, with forecast rain totals less than a tenth of an inch. Friday, skies will clear. The shortwave low pressure system will push eastward out of our area, allowing ridging to meander in from the Pacific. This increase in heights will maintain above-average temperatures over the region going into the weekend with Saturday shaping up to be the hottest day of the week at 6-8 degrees above seasonal averages. .LONG TERM...Sunday through next Wednesday. As previously advertised, we are expecting a fairly potent trough to drop down from the Pacific Northwest this weekend. Ensembles continue to indicate that uncertainty lies in both timing and the magnitude of this trough. That said, though details remain uncertain, we have high confidence that this trough is stronger than what is seasonally expected for this time of the year. As a result, the gusty southwest winds with speeds 40-45 MPH on Sunday, coupled with relative humidity values in the single-digits have warranted a Fire Weather Watch. This watch is in effect from early Sunday morning through late Sunday night areawide, lasting through Monday for portions of Mohave County. A Fire Weather Watch means that conditions are expected to be favorable for rapid wildfire starts. Outdoor activities such as burning or fireworks may provide additional sources of fire ignition and are not advised when near dry brush. Though the Fire Weather Watch only encompasses portions of Mohave County on Monday, gusts will remain elevated areawide; they simply are not forecast to achieve "critical" speeds elsewhere. Along with enhanced winds, this trough will drop temperatures fairly drastically, going from effectively 6-8 degrees ABOVE average on Saturday to 6-8 degrees BELOW average on Monday. Afternoon high temperatures for the desert valleys including Las Vegas are forecast to drop to the low-to-mid 90s Monday and Tuesday. The speed and exit timing of this trough remain uncertain, though ensemble model temperatures and upper-level heights indicate the return of a ridge of high pressure by mid-week. && .AVIATION...For McCarran...East to northeast winds 5 to 10 knots are expected through much of the day. A shift to a more southerly direction is possible in the afternoon, with a few gusts as high as 20 knots possible through sunset. Winds might remain southerly all day Thursday, or there could be a brief period of easterly winds during the day. No operationally significant clouds expected. For the rest of southern Nevada, northwest Arizona and southeast California...Winds under 20 knots are expected for most of the region through Thursday. Possible exceptions will be the usual push of west to southwest winds into the Barstow area late in the afternoons, and spotty thunderstorm outflow winds from the Sierra crest across the southern Great Basin in the afternoons. Aside from the isolated thunderstorms mentioned above, no operationally significant clouds are expected. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ UPDATE...Pierce DISCUSSION...Varian AVIATION...Morgan For more forecast information...see us on our webpage: or follow us on Facebook and Twitter