Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/08/24


Area Forecast Discussion
National Weather Service Amarillo TX
704 PM CDT Wed Aug 7 2024 ...New AVIATION... .SHORT TERM... (This evening through Thursday night) Issued at 142 PM CDT Wed Aug 7 2024 Yet another very hot day today as the Panhandles are on the eastern periphery of the upper-level ridge. A seasonably robust upper-level trough will dip into the Upper Midwest tonight, and a cold front will move through the Plains through the night and through the day Thursday. The GFS, NAM, and most CAMs are in surprisingly good agreement through 1 PM Thursday regarding the frontal timing... both of which bring the front through all but the southeast Texas Panhandle. The 00z ECMWF and 12z HRRR have a more west-to-east oriented front, and have it located around the I-40 corridor by 1 PM Thursday. However, the 12z ECMWF has come in slightly more similar to the GFS/NAM/most CAMs camp. This timing will be important as it will have a significant impact on the highs, but there is good enough agreement that Collingsworth county will be ahead of the front long enough in the afternoon, and with aid from compressional heating associated with the front, to warm up to 105 degrees for a Heat Advisory. The main question is whether Donley and Wheeler counties will stay ahead of the cold front for long enough, and as of right now, it seems as though they may reach into the low-100s before the front, but not quite to Heat Advisory criteria. On the other hand, due to widespread cloud coverage behind the front, the northern Panhandles may see their high temperature occur in the morning hours. Behind the front will be a pretty steep surface pressure gradient which should lead to breezy winds on the order of 15-25 kts. There will also be some impressive moisture content pooled up behind the front with PWATs around the 90th percentile. An embedded shortwave trough may sneak into the northern combined Panhandles Thursday night which may lead to showers and thunderstorms, but there is not ideal agreement among guidance regarding this potential as a couple CAMs (NAM NEST and FV3) keep much of the area dry. If it does pan out, heavy rain will be a distinct possibility given the high PWATs and sufficient instability for some thunderstorms. Strong to severe thunderstorms do not look like much of a concern given the somewhat limited instability. Flash flooding can`t be ruled out, but would need rounds of storms to train over a location for that to be possible. Vanden Bosch && .LONG TERM... (Friday through next Tuesday) Issued at 142 PM CDT Wed Aug 7 2024 Friday looks to feature below average temperatures for the Panhandles as the post-cold frontal airmass sticks around, especially in the northern Panhandles. There may be room to lower temperatures further if morning clouds persist through the afternoon, but currently the expectation is that the clouds will break in the southern half of the Panhandles by the early afternoon hours. If the NAM is correct, which has the more aggressively cool airmass and most persistent clouds, much of the western and northern halves of the Panhandles may not reach 70 degrees. However, this is the outlier at this point. A ridge riding shortwave trough is favored to move into the northern combined Panhandles Friday night. This looks to be the most favorable chance for showers and perhaps some thunderstorms through this forecast package. Given the high PWATs in place, expecting heavy rain and lightning to be the most prominent hazards. A couple CAMs suggest there may be 1000-1500 J/kg of elevated instability which could lead to a stronger thunderstorm, but not overly concerned as thunderstorms, if there are any, should be elevated. That said, can`t rule out some small hail as there will be some wind shear and modestly cool temperatures aloft if that instability does verify. Saturday and beyond, temperatures warm back up quickly such that 100s return by Sunday and cover the majority of the Panhandles by Monday. The GFS keeps the center of the upper-level ridge oriented more into southeastern NM/southwestern TX while the 12z ECMWF keeps it slightly stronger and more broad across the Southern US like previous runs. The pattern on the GFS would favor daily chances for thunderstorms across the Panhandles due to the northwesterly flow aloft, while the ECMWF would favor mostly the northern combined Panhandles with chances for thunderstorms every day or every other day. Vanden Bosch && .AVIATION... (00Z TAFS) Issued at 657 PM CDT Wed Aug 7 2024 For the 00Z TAFs, a cold front will move across the terminal sites late tonight and Thursday morning with gusty north winds at times behind this boundary. Isolated thunderstorms may develop across northwestern sections of the area later Thursday afternoon. However, confidence is low as to timing, location, and expected isolated coverage so have opted not to mention at KDHT or KGUY for this issuance. 02 && .PRELIMINARY POINT TEMPS/POPS... Amarillo TX 70 94 65 88 / 0 10 20 20 Beaver OK 69 86 60 78 / 10 10 40 20 Boise City OK 65 80 57 79 / 20 40 50 30 Borger TX 73 94 65 90 / 0 10 30 20 Boys Ranch TX 68 94 63 89 / 0 10 30 20 Canyon TX 68 97 64 89 / 0 10 20 20 Clarendon TX 71 101 65 89 / 0 10 20 10 Dalhart TX 65 86 60 85 / 10 20 40 20 Guymon OK 66 83 58 78 / 20 20 50 20 Hereford TX 68 97 65 91 / 0 10 20 10 Lipscomb TX 73 93 62 83 / 0 10 30 20 Pampa TX 71 93 62 85 / 0 10 30 20 Shamrock TX 73 103 65 87 / 0 10 20 20 Wellington TX 73 106 67 91 / 0 10 20 10 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...Heat Advisory until 8 PM CDT this evening for TXZ005-007>010- 012>015-018>020. Heat Advisory from 1 PM to 8 PM CDT Thursday for TXZ020. Excessive Heat Warning until 8 PM CDT this evening for TXZ317. OK...None. && $$ SHORT TERM...52 LONG TERM....52 AVIATION...02
Area Forecast Discussion
National Weather Service Boise ID
820 PM MDT Wed Aug 7 2024 .DISCUSSION...An area of high clouds (20-35kft MSL) will continue lifting northward overnight as flow aloft becomes more southerly. Clouds are blocking the satellite view of fire temperature and smoke, but the continuation of west to north surface winds overnight will push smoke south and east. Outside of the vicinity of the fires, expect highest concentrations to setup over Harney County, the w-central and Boise mountains and along the foothills in the Snake Plain. Have updated the forecast for cloud cover overnight. && .AVIATION...Low VFR/MVFR with local IFR visibility near wildfires (KBNO, KBOI). Patchy mountain obscuration. Surface winds: variable 5-10 kt overnight into Thursday. Winds aloft at 10kft MSL: W-SW 5-15 kt. KBOI...Periods of MVFR/IFR conditions from dense smoke. The lowest visibility will be along the N-E quadrants. Broken high clouds. Surface winds: SE 4-8 kt overnight through 21Z/Thu, then NW 4-8 kt. Brief visibility improvement is possible Thursday afternoon. && .PREV DISCUSSION... SHORT TERM...Tonight through Friday night...Near-surface smoke has become worse in western Idaho due to the Paddock Fire north of Emmett. Latest HRRR shows a band of thick smoke spreading southward from the fire into the Treasure Valley just before sunset and continuing through around 3 AM MDT. After that it spreads into the Magic Valley but not quite as thick. On Thursday night the HRRR shows the smoke from that fire even worse than tonight in the Treasure Valley. The smoke may lower high temps slightly Thursday and Friday but not affect low temps. Latest models keep our CWA dry through Thursday but a slight chance (10-20 percent) of thunderstorms appears in Harney County Thursday evening. By Friday morning a 15-25 percent chance of showers and thunderstorms will extend from Baker County eastward across the Weiser River area into the Boise Mountains. On Friday afternoon a 30-50 percent chance of thunderstorms is indicated in central Idaho near the eastern edge of our CWA. A 20-30 percent chance of thunderstorms will continue Friday night in Baker County/OR and the Boise Mountains in Idaho. Winds will stay generally light and variable through Friday morning, then north or northwest Friday afternoon. Gusts up to 25 mph in southeast Oregon and in the southwest Idaho Highlands. LONG TERM...Saturday through Wednesday...Dry west to southwesterly flow will continue through the long term. Monsoon moisture will generally stay to the SE of the forecast area. Temperatures will be a few degrees above normal, but wildfire smoke may keep high temperatures down a few degrees in the long term. && .BOI WATCHES/WARNINGS/ADVISORIES... ID...None. OR...None. && $$ www.weather.gov/Boise Interact with us via social media: www.facebook.com/NWSBoise www.twitter.com/NWSBoise DISCUSSION...DG AVIATION.....SH SHORT TERM...LC LONG TERM....KA
Area Forecast Discussion
National Weather Service Cheyenne WY
854 PM MDT Wed Aug 7 2024 .UPDATE... Issued at 842 PM MDT Wed Aug 7 2024 Severe weather threat has ended across far southeast Wyoming and the southern Nebraska Panhandle for the rest of tonight, so the Severe Thunderstorm Watch has been cancelled a few hours early. Forecast for tonight has been updated with current Surface cold front will continue moving south into Colorado late this evening. We should have a 2 to 4 hour lull before showers and thunderstorms redevelop along the front. These showers may be locally heavy at times through early Thursday morning, but the thunderstorms should be sub-severe. A chilly early August day is forecast for Thursday with cloudy skies, areas of fog, and temperatures stuck in the upper 50s to mid 60s. The only exception will be Carbon County which may see highs in the mid 70s to low 80s. && .KEY MESSAGES... - Showers and storms will continue tonight into Thursday with the cold front passage dropping temperatures well below normal for early August. - Expecting a gradual warmup through the weekend returning to near normal temps. && .SHORT TERM /THROUGH FRIDAY NIGHT/... Issued at 300 PM MDT Wed Aug 7 2024 Cold front lays across central South Dakota...southwestward into the northern Panhandle...to Torrington and then northwestward to Riverton this afternoon. Thunderstorms have been developing along and south of this front. RAP mesoanalysis guidance showing SBCAPE south of the front around 2000 J/KG across southeast WYoming and near 3000 J/KG across the southern Panhandle. Still a little capped in the southern Panhandle with low level CIN near -50 to -75 J/KG. Surface to 6km shear at 21Z near 40kts across Cheyenne into the southern Panhandle. As the afternoon progresses...believe we will see an increased threat for severe thunderstorms and heavy rainfall. SBCAPE increases to 3500 J/KG across the southern Panhandle as the front approaches from the north. HRRR simulated radar showing discrete supercells developing as early as 22Z...continuing through at least 01Z. Severe Thunderstorm Watch 611 has been issued for the area through 04Z tonight. One caveat would be the anvil cirrus in northern Colorado limiting instability over our watch area. Will continue to monitor. Cold front move through the Cheyenne area between 03Z and 06Z this evening with northeasterly low level winds developing behind the front. Could see showers continuing overnight as suggested by the HRRR/RAP simulated radars. Have followed their guidance for tonight into Thursday. Another concern for tonight will be low level stratus and fog for the Panhandle airports to Cheyenne overnight. Temperatures at 700mb behind the front cool down to the single digits (+4 to +6C) across our eastern zones Thursday. Temperatures Thursday likely in the 60s across our eastern zones with the warmest temperatures out near Rawlins on the west side of the front. Could see stratus and fog persisting through much of the day Thursday east of the Laramie Range. The front does not move too much through the evening Thursday into Friday. So another cool day expected. PWATS remain high Friday with over an inch in the Panhandle and near 1 inch at Cheyenne. If we can get a few breaks in clouds to allow some surface heating...could see good chances for showers and storms && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Issued at 300 PM MDT Wed Aug 7 2024 The long term will see a return to warmer temperatures while sustaining a fairly active pattern with near-daily chances for precipitation across the forecast area. Broad ridging will build over much of western CONUS this weekend, leading to the start of warming temperatures throughout the extended forecast. This stagnant ridge will linger over much of the country into next week, allowing for gradual warm air advection out of the southwest. 700 mb temperatures on Saturday will range from the upper single digits to about 14C, leading to slightly below average temperatures across much of the CWA. Temperatures return to average by Sunday, with 700 mb temperatures a few degrees warmer. High temperatures will continue to rise through mid-week, with 700 mb temperatures approaching the 90th percentile for climatology by Tuesday afternoon. By Tuesday, high temperatures could be back into the low 90s for many areas east of the Laramie Range. As mentioned, the long term will be fairly active, with almost daily chances for showers and thunderstorms. The position of the upper- level high over Texas, and the near stationary nature of the ridge, will lead to south to southwest flow throughout the majority of the long term. This will allow the CWA to tap into monsoon moisture, raising PWs across much of the area. A few shortwaves moving through the ridge for the duration of the long term, as well as the increased moisture, will lead to scattered storms over the weekend and into next week. && .AVIATION /18Z TAFS THROUGH 18Z THURSDAY/... Issued at 1117 AM MDT Wed Aug 7 2024 Showers and thunderstorms will affect CYS, LAR, BFF, SNY and possibly AIA this afternoon. Gusty outflow winds from the west as well as VIS and brief CIG reductions are possible into the MVFR and perhaps IFR range for a few minutes. Later this evening, a cold front will drop south from the north bringing low stratus clouds to all terminals from I-25 eastward. IFR ceilings are likely with this event especially at CYS, BFF and SNY. There is some uncertainty if IFR ceilings will make it into LAR overnight and the current forecast may be adjusted later to account for a more favorable wind direction flow. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ UPDATE...TJT SHORT TERM...GCC LONG TERM...SF AVIATION...MAC
Area Forecast Discussion
National Weather Service Dodge City KS
1100 PM CDT Wed Aug 7 2024 ...Updated Aviation... .KEY MESSAGES... - Thunderstorm system to impact areas along/north of Highway 96 tonight with Marginal Risk (Level 1 of 5) of severe storms, mainly midnight or after - Much cooler temperatures with highs in the 70s for up to three straight days (Thursday-Saturday) - Friday Night and Saturday Night will be the best chances for large thunderstorm cluster(s) to move across southwest Kansas with a high chance (40-50%) of widespread 1"+ across much of our region out of the two days combined through Sunday morning. && .DISCUSSION... Issued at 350 PM CDT Wed Aug 7 2024 The major pattern change that has been the focus of previous discussions was underway this afternoon as the summer subtropical ridge continued to weaken with increased west-northwest flow aloft across Wyoming and Montana...into Nebraska and the Dakotas. Winds behind yesterday`s front became southerly to southeasterly with warm, moist air mass nosing back to the northwest into northeastern Colorado. Satellite was already showing incipient thunderstorm development over the Front Range and the Cheyenne Ridge region. All short term convection-allowing models (CAMs) show a strong signal of a rather well-organized mesoscale convective system (MCS) through the nighttime hours, tracking east-southeast along the favorable Theta-E axis. Using the 12Z HREF 25km neighborhood 60% contour of 35+ dBZ Composite Reflectivity, the MCS will most likely track from northeast Colorado across northwest Kansas, reaching roughly a US-283 line from Norton to near WaKeeney by 05-06Z time frame (Midnight-1 AM CDT). 50-60% (25km neighborhood) probs continue all the way into north central/central KS by 09Z (4 AM CDT) and onward towards east central Kansas toward daybreak Thursday. This MCS is likely to at least clip our northern counties Trego-Ellis to the point that we have increased POPs to 60+ for WaKeeney and Hays. Most areas of our southwest Kansas region, south of Highway 96, will most likely not see much precipitation with this initial MCS to start this multi-day pattern, but the wind shift from a fairly intense outflow boundary will be felt in the 09-12Z time frame early Thursday morning. Winds will likely gust 35 to 45 mph at times, well away from the MCS with even higher gusts closer to the MCS late in the night. In fact, the latest 18Z run of the HRRR is modeling 50+ knot gusts from near Hays down to around Great Bend immediately in advance of the MCS from the well-developed cold pool. The outflow boundary itself will not necessarily be the synoptic front passage itself, although the synoptic front will push in a few hours after later in the morning, only increasing the low level cold air advection which will continue much of the day Thursday along with low stratus cloud cover (12Z HREF Probability of Broken-Overcast Low Cloud Cover 70% or greater advancing south beginning mid-late morning). The official afternoon temperatures will follow closely the 25th percentile 12Z HREF numbers given the forecast of low clouds and low level cold advection, which results in afternoon highs near 70F around Scott City to WaKeeney...lower-mid 70s down to Garden City-Jetmore-La Crosse...to lower 80s for highs from Ashland to Pratt. It is quite possible we are not going far enough south with the 75F isotherm for late afternoon temperatures, but that will be refined in the overnight update. Looking ahead, Friday and Saturday will also be cool and moist, but the east/southeast upslope low level winds will draw low level moisture back into Colorado for more thunderstorm development. The axis of Friday Night and/or Saturday Night MCS will likely focus on west central and southwest Kansas, and if the MCS is large, most of our forecast area will see well in excess of a half an inch of rain (100-member Grand Ensemble 24-hr QPF in excess of 0.50" at 40% percent, ending 12Z Saturday). The same probabilistic field shows 30- 50% across the southeastern half of the DDC CWA over the next 24-hr period ending 12Z Sunday. Using more probabilistic numbers off the latest 12Z Grand Ensemble, combining the two best looking nights (Friday Night and Saturday Night), the probability of 1"+ comes out to 40-50% across almost the entire forecast area, further increasing our confidence that either one or both of the nights coming up will really focus on west central, southwest, and south central Kansas. Saturday Night will not be the end of it, as we will not see the summer subtropical ridge build back in any time soon next week, so once the atmosphere recharges again with instability and we see deep tropospheric moisture move back north through the week (which will eventually happen), more MCSs will be likely affecting our region. && .AVIATION /06Z TAFS THROUGH 06Z FRIDAY/... Issued at 1100 PM CDT Wed Aug 7 2024 Radar at 04z depicted a MCS in progress across west central and northwest Kansas, with more scattered rain showers in the vicinity of GCK/LBL. Overnight through 12z Thu, activity will focus eastward toward the HYS vicinity, where -SHRA was included for several hours Thursday morning. All other TAFs were left dry. An unseasonably strong cold front is expected to arrive during the 15-18z Thu time range, with a sharp increase in northeast winds, gusting to near 30 kts. Followed the stronger NAM winds for this TAF package. Widespread post frontal MVFR stratus is expected Thursday morning/midday, most likely at GCK/HYS, with lesser confidence at DDC, and none at LBL. && .DDC WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Umscheid AVIATION...Turner
Area Forecast Discussion
National Weather Service Green Bay WI
1027 PM CDT Wed Aug 7 2024 Updated aviation portion for 06Z TAF issuance .KEY MESSAGES... - Some rivers and creeks over central and east-central Wisconsin will continue to run high through late this week due to recent heavy rain. - On and off chances for showers return tonight and continue through this weekend. Isolated thunderstorms will be possible at times, but the risk of severe weather and flooding is low. - Cool and breezy weather is forecast for Friday and Saturday. A small craft advisory may be need at times due to gusty northwest winds. && .DISCUSSION... Issued at 229 PM CDT Wed Aug 7 2024 Short Term...Tonight and Thursday The latest RAP analysis and satellite/radar imagery show a weak area of high pressure stretching from southwest to northeast across Wisconsin early this afternoon. However, mid and high clouds are rapidly spreading across the area from the west and ahead of cold front positioned across northwest Minnesota and the central Dakotas. Scattered thunderstorms are occurring along the front in a region of elevated instability over South Dakota and Nebraska. As this front moves across the region, precipitation and thunderstorm potential are the focus of this forecast. Precipitation: Strong height falls over the northern Plains and northern Mississippi River Valley will push the cold front east and across the region from late tonight through Thursday afternoon. A pre-frontal shortwave impulse could bring an area of showers to north-central Wisconsin this evening and will carry low precip chances. Thereafter, chances of rain will increase (60-70%) late tonight over central and north-central WI with the approaching front. In general, precip chances will diminish as the front moves into eastern WI as the precipitable water axis thins out. But scattered showers will also be possible over northeast WI by midday through late afternoon. Thunderstorm Potential: The front will be moving into north- central WI during the diurnal minimum of instability. Elevated instability is forecast to be under 100 j/kg, so thunderstorm chances look low (10-20%). Even with daytime heating, forecast instability is only expected to reach 100-200 j/kg which doesn`t point to the possibility of strong storms. An isolated thunderstorm cannot be ruled out and will leave a slight chance mention in the forecast. Long Term...Thursday Night Through Wednesday Generally, cool and showery weather is forecast on Friday and Saturday, which will be followed by a warming trend next week. This weekend: Upper level low pressure will be spinning over the Lake Superior region through Saturday before exiting to the east on Sunday. On the southern periphery of this upper low, breezy northwest winds will usher in cool airmass into the region with 850mb temps falling to 3-5C over northern WI. Low convective temps combined with unstable conditions over Lake Superior will likely lead to showery weather at times, particularly in the afternoon with the heating of the day. The shower activity will be most widespread over far northern WI where moisture will be deeper and there is additional support from lake effect. Northwest winds will be breezy at times with gusts of 25 to 30 mph expected. Small craft advisories look likely at times. Temps will be the coolest on Friday with highs in the 60s to near 70. Then readings warm back into the low to middle 70s by Sunday. Next week: Temperatures moderate as the upper trough exits and mid and upper flow back to the west. Weak high pressure will be present during the early to middle of next week. Models indicate light precip will be possible around the middle of the week, but the systems look low amplitude and predictability is low. && .AVIATION...for 06Z TAF Issuance Issued at 1023 PM CDT Wed Aug 7 2024 Scattered light showers or sprinkles were occurring over northern and parts of central WI late this evening, but VFR conditions prevailed. Flight conditions are expected to deteriorate to MVFR/IFR at RHI, and MVFR at AUW/CWA overnight into Thursday morning as showers increase with the arrival of a cold front. Scattered showers should also impact the Fox Valley during the early to mid afternoon, along with potential for a brief period of MVFR ceilings. Although an isolated storm or two is possible with the frontal passage, the probability is too low to include at any given TAF site. As the rain ends from west to east on Thursday, ceilings should gradually rise, and clearing should occur during the mid to late afternoon. Some low clouds may work their way back into NC WI late Thursday evening, but perhaps not until after 06z/Fri at RHI. Light southerly winds will become westerly after the frontal passage, with gusts to around 20 knots possible at times on Thursday. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....MPC AVIATION.......Kieckbusch
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
854 PM CDT Wed Aug 7 2024 .KEY MESSAGES... - Patchy fog is possible tonight near the Illinois River Valley and portions of the I-74 corridor and may reduce visibility to under a mile in spots. - Slightly below normal temperatures and dry weather will prevail through the remainder of the week and into this weekend. && .UPDATE... Issued at 854 PM CDT Wed Aug 7 2024 Nighttime microphysics satellite imagery shows the pesky stratus that stuck around all day is at last breaking up, which has recently hastened the decline in temps. Visibilities still remain 10sm across the Prairie State, but dew point depressions (currently 3-6 degF) are on the decline and both the ARW and HRRR continue to suggest transient/patchy fog developing before dawn. Only small changes were made to expand the patchy fog mention in our forecast between 5 and 8 am tomorrow (i.e., Thursday) morning. Bumgardner && .DISCUSSION... Issued at 206 PM CDT Wed Aug 7 2024 THROUGH TONIGHT... This afternoon, low pressure has settled south of the Ohio Valley and is departing the region while high pressure is spreading east from the Upper Midwest across the Great Lakes. Ridging extending SW from the high will overspread central Illinois this evening and overnight. Skies should be able to gradually clear from the NW in response allowing for strong radiational cooling. Temps are expected to fall into the lower 60s tonight with a few spots near and north of the I-74 corridor dipping into the 50s. Meanwhile, some patchy fog is possible, especially across portions of the lower and mid Illinois River Valley closest to the ridge axis tonight. THURSDAY... Low pressure will very slowly track east across northern Ontario Thursday pushing a cold front across portions of the Upper Midwest and Great Lakes. The tail end of the cold front or col area / neutral point will track across central Illinois. Weak forcing, dry mid levels, and strong capping should prevent any convection from occurring with passage of this feature. In its wake, a modest northerly breeze will overspread central Illinois with gusts picking up to around 20mph at times Thursday evening and overnight. FRIDAY THROUGH THE WEEKEND... Behind Thursday`s cold frontal passage, a reinforcing shot of cooler air will overspread central Illinois. Cold air advection will drive steep lapse rates Friday which will allow gusty winds to mix down to the surface, peaking in the 20 to 25 mph range Friday afternoon. Meanwhile, temps will bottom out Friday and Saturday with highs generally in the mid 70s and lows Saturday morning in the lower to mid 50s. Surface ridge axis will overspread much of hte Midwest this weekend resulting in fair weather conditions. NEXT WEEK... High pressure will shift east with the baroclinic zone lifting back north to portions of the mid Mississippi River Valley starting early next week. Warm air advection across central Illinois will drive daily precip chances through the first half of next week. Temperatures will also undergo a gradual warming trend through at least the first half of next week with low to mid 80s back in the forecast by Wednesday. Deubelbeiss && .AVIATION... (For the 00z TAFs through 00z Thursday Evening) Issued at 639 PM CDT Wed Aug 7 2024 MVFR ceilings have at last lifted into the low VFR category (generally FL040 to FL050) this evening. Guidance continues to suggest these clouds will dissipate completely, but this process seems to be taking longer than modeled so there are some doubts as to whether and when this will happen. This has been pushed back another hour in this TAF package, until around 02z/9pm. Winds will continue to gradually ease tonight, becoming light to favor radiational cooling for some patchy fog towards daybreak. Confidence is low in where and when this will occur, but has been most consistent at PIA nearer the current back edge of the stratus. After around 13z, whatever fog manages to form will quickly burn off while stratocumulus with bases near the MVFR/VFR threshold of FL030 redevelops. HREF guidance only suggests a 30-45% chance this becomes a ceiling (highest at SPI, DEC, and CMI), with slightly lower chances of it being MVFR, though guidance has been underdoing current clouds so ultimately the current forecast could be slightly too optimistic. We`ll reassess at the 06z package issuance. Bumgardner && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$
Area Forecast Discussion
National Weather Service North Platte NE
645 PM CDT Wed Aug 7 2024 .KEY MESSAGES... -Thunderstorm chances are the main concern late this afternoon and especially this evening. Strong gusty winds would be the main threat across portions of southwest Nebraska this evening. -Cooler and showery weather is expected both Thursday and Friday. Friday highs across portions of the region have the potential of being the coolest since August 1997. -Temperatures do moderate during the weekend, but will still remain below normal. -Areas of the next several days could see between 1-2" of rainfall. The precipitation will be showery/convective in nature, so amounts will likely vary with some not seeing those types of amounts. && .SHORT TERM /THROUGH FRIDAY/... Issued at 238 PM CDT Wed Aug 7 2024 A cold front is moving slowly southward through the Sandhills this afternoon. South of this front low-level southeasterly upslope flow is helping to maintain a moist instability axis from southwest Nebraska into the southern Nebraska Panhandle. Scattered thunderstorms are expected to develop across the higher terrain of a eastern Wyoming and northern Colorado late this afternoon ahead of an approaching shortwave. Effective shear profiles/instability are supportive of storm organization across the central and southern Panhandle late this afternoon. Recent runs of the HRRR and CAMs suggest a cold pool will form with a damaging wind threat becoming possible as storms accelerate southeastward across southwest Nebraska this evening. Other storms may develop along the southward sagging front across portions of north central Nebraska as mid-level FGEN increases after early evening. The most intense storms should exit the area by later this evening, but favorable jet dynamics and mid-level FGEN will remain in place through Friday morning. This seems a good set up for at least scattered showers. Elevated weak instability remains so some thunder is also possible. The other story will be the much cooler temperatures that will filter south into the region behind the cold front. Friday looks particularly cool, with the lingering cloud cover and possible morning light precipitation. Highs are forecast to be in the mid 60s across portions of the Sandhills and southwest Nebraska. The last time North Platte experienced a high of 65 degrees or cooler was August 11, 1997. Highs are forecast to be right around this mark, so this is an exceptionally cool pattern. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... Issued at 238 PM CDT Wed Aug 7 2024 Below normal temperatures are expected through this weekend into the first of next week. Northwest flow aloft will persist, and a series of weak shortwaves will bring an increasing chance for showers/thunder back to the area Sunday night into Monday. Highs through the weekend should generally average in the lower to mid 70s. Highs Monday may moderate slightly, but with increased cloud cover and showers around may be hard pressed to reach much above 80. By the middle and end of next week, upper level ridging aloft begins to expand northward once again across the Rockies and western high plains. This will bring a return to at least normal temperatures. Monsoonal sub-tropical appears to develop northward within the expanding ridge. This will likely bring diurnal rounds of convection to the higher elevations of Colorado and Wyoming. Some of this activity may try and work eastward during the overnight hours, so there will be at least some chance for spotty rainfall. && .AVIATION /00Z TAFS THROUGH 00Z FRIDAY/... Issued at 638 PM CDT Wed Aug 7 2024 VFR conditions are expected across western and north central Nebraska tonight outside of thunderstorms. Any thunderstorms this evening and tonight may result in brief MVFR conditions and gusty, erratic winds across the Sandhills into southwest Nebraska, potentially impacting LBF. Timing of activity at LBF anticipated between 03Z to 05Z Thursday with the bulk of any thunderstorms remaining south of VTN. Will rely heavily on radar and satellite trends for possible amendments. Stratus development appears likely across western and southwestern Nebraska Thursday morning, with IFR CIGs anticipated. Though this appears to remain south and west of KLBF, this will need to be monitored with subsequent TAFs. && .LBF WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...Taylor LONG TERM...Taylor AVIATION...Viken
Area Forecast Discussion
National Weather Service Melbourne FL
852 PM EDT Wed Aug 7 2024 ...New UPDATE, MARINE... .UPDATE... Issued at 852 PM EDT Wed Aug 7 2024 Isolated convective chances coming to an end around mid-late evening; first along the Volusia coast with some activity dropping southward and second south from Melbourne. Otherwise some ISOLD- SCT showers and lightning storms remain possible over the adjacent coastal waters overnight. SWRLY gusty winds should diminish this evening to around 10 mph or less. Another very warm night is in store, with lows forecast in the U70-L80s once again. && .AVIATION... (00Z TAFs) Issued at 724 PM EDT Wed Aug 7 2024 Isolated convection remains possible thru mid-late evening near KDAB, and further towards KMLB southward, otherwise conditions mostly dry overnight. Winds remain out of the southwest, diminishing less than 10 kts overnight. Winds will increase back to 8-12 kts on Thu with some occasional higher gusts. Guidance is hinting at the potential for some VCSH/VCTS tomorrow afternoon beyond 18Z. VFR conditions prevailing outside of convection. && .MARINE... Issued at 852 PM EDT Wed Aug 7 2024 .Updated...Overnight...Winds continue below guidance and will replace the offshore Small Craft Advisory with Cautionary Statements overnight for southwest winds of 15 to 20 knots well offshore. Seas 2-3 ft near shore and 3-4 ft offshore. Isolated to Scattered showers and lightning storms will remain possible, esp over the Gulf Stream. && .PREVIOUS DISCUSSION... Issued at 404 PM EDT Wed Aug 7 2024 Key Messages: - Heat impacts expected to increase Thursday into Friday as temperatures quickly climb into the 90s, which combined with increasing humidity, will result in heat index values of 105-110 and Major HeatRisk. Recap of the Day...Low-level moisture and instability, plus a jump start from lightning storms that formed in the Gulf of Mexico, were able to overcome the dry mid-levels and produce a semi- continuous line of strong lightning storms that pushed across the southern counties from the late morning through the afternoon, right into the Heat Advisory. Vero Beach, Fort Pierce, Stuart, and Okeechobee airports all managed to reach peak heat indices of 108 in the early afternoon, but showers and storms then brought temperatures down and relief to those areas, most of which are still in the 80s as of 330 PM. Rest of Today-Tonight...Most of the showers and lightning storms have pushed south and offshore, and while a few more are attempting to develop on the western side of the peninsula, they`re moving into areas already worked over and struggling. The HRRR remains optimistic some of this could become more vigorous as it moves into the southern counties, which have been warming back up, so keeping 20-30 pct PoPs across the southern counties in the forecast. RAP analysis shows plenty of instability remains draped across this area (MUCAPE up to 4,000 J/kg and MLCAPE up to 3,000 J/kg), so there continues to be potential for stronger storms capable of gusty winds to 50 mph, frequent cloud to ground lightning, and locally heavy rainfall. Will also continue 20-30 pct PoPs to the north for rain band like showers and storms from southern extent of Tropical Storm Debby, but the environment is much less favorable for stronger storms. Locations that stayed dry are forecast to see highs reach the L-M90s, and spots that got a good soaking should top out near 90 in the next hour or so. Another very warm night is in store, with lows forecast in the U70-L80s again. Thursday - Friday (Previous Discussion)...Offshore flow wins out as the surface ridge axis holds well south of us. Sea breeze formation looks very tough on Thursday (except perhaps along the Treasure Coast) with a better chance of a pinned sea breeze by Friday. So, with limited convergence and a slight diminution of moisture aloft, we`ll be relegated to airmass-type storm development on Thursday (~40% coverage). By Friday, moisture increases slightly, leading to a 50-60% chance of afternoon showers and storms. The low-level thermal ridge noses from Louisiana to North and Central Florida through this timeframe, ensuring continued sweltering temperatures. Statistical guidance keeps us in the mid 90s both afternoons. Thursday is likely to be the warmer of the two as low-level thicknesses max out over the peninsula; a few upper 90s could even occur. Heat indices from 105-110F are forecast, once again encroaching on Heat Advisory criteria. Major HeatRisk should persist over much of the area, indicative of an environment where anyone can succumb to heat illness without proper access to cooling and hydration. This Weekend (Previous Discussion)...As mentioned above, a slight weakness in the H5 field continues to appear in the ensemble means. Moisture increases just a touch, and with lessening background winds, the sea breeze circulation should get going in earnest. This portends better coverage of afternoon showers and storms (50-70%). Those low to mid 90s are not going anywhere, but hopefully, some of us will see some cooling rain. Max heat indices should reach 102-107F each day. Early Next Week (Previous Discussion)...The surface high-pressure axis will attempt to lift toward Central Florida as ensembles cluster on a NW-SE oriented H5 ridge axis from TX to FL. With H5 T`s rising toward -4C beneath the ridge, capped rain/storm chances just slightly below climatology (40-50%) next Mon-Wed. Widespread low/mid 90s are predicted to continue along with triple-digit heat indices. && .MARINE... Issued at 404 PM EDT Wed Aug 7 2024 Rest of Today-Tonight...The southern periphery of Tropical Storm Debbie continues to influence marine conditions in the local Atlantic waters. The wind forecast has been very tricky. Pressure analysis and low-level winds would generally point to winds higher than observed. Have been adjusting winds down, but also don`t want to over correct, especially since low-level winds are forecast to increase tonight over the Volusia and Brevard offshore waters. Thus have not just continued the Small Craft Advisory for the aforementioned waters, but also extended later tonight for winds around 20 kts. However, this is a very marginal SCA, and mainly for well offshore. Small craft should exercise caution in the Treasure Coast offshore waters. Closer to shore, boating conditions improving as winds decrease to 10-15 kts with seas 2-3 ft, and should be generally favorable by morning. Thursday-Sunday (Previous Discussion)... High pressure remains to our south as Debby departs, leaving us with SSW winds of 10-17 KT Thu/Fri, then 7-13 KT this weekend. Limited sea-breeze development until Friday and the weekend. Seas 2-4 FT Thu, then 2-3 FT thereafter. A daily chance (30-50%) of showers and a few storms. && .PRELIMINARY POINT TEMPS/POPS... DAB 78 96 78 94 / 40 40 10 50 MCO 80 95 79 94 / 20 40 10 60 MLB 78 94 77 93 / 20 40 20 50 VRB 77 94 76 93 / 20 40 10 50 LEE 80 94 79 93 / 20 40 10 50 SFB 80 95 79 95 / 30 50 10 50 ORL 81 95 79 94 / 20 40 10 60 FPR 77 94 76 93 / 20 40 10 50 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...None. AM...Small Craft Advisory until 6 AM EDT Thursday for AMZ570-572. && $$ UPDATE...Sedlock AVIATION...Sedlock
Area Forecast Discussion
National Weather Service Phoenix AZ
420 PM MST Wed Aug 7 2024 .Update...00Z Aviation Discussion && .SYNOPSIS... Thunderstorm chances will continue this afternoon and evening across south-central Arizona with the greatest chances across the higher terrain areas north and east of Phoenix. Thunderstorms will be capable of producing strong winds along with locally heavy rainfall. Rain chances will gradually diminish into the weekend with chances retreating to mainly over higher terrain areas by Saturday as drier air works into the region. Near to slightly below normal temperatures today and tomorrow will give way to warming temperatures heading into the weekend with highs likely topping out near or above 110 degrees across the lower deserts. && .DISCUSSION... The latest satellite WV imagery and RAP analysis showed an inverted trough situated over the northern Gulf of California near the international border with southwest Arizona and northern Mexico. Temperatures so far this afternoon are running around 5-10 degrees cooler compared to 24 hours ago with many lower desert areas still under the century mark early this afternoon. Highs this afternoon will generally top out between 100-106 degrees, which is near to slightly below normal for this time of year. Early afternoon satellite and radar showed convection along the Mogollon Rim along with a few storms popping up across southeast Arizona. Easterly steering flow around 10-15 kts will help push thunderstorms off the Rim and into southern Gila County through this afternoon into the early evening hours. MUCAPE values upwards of 1000-1500 J/kg along with DCAPE values around 1000-1500 J/kg may support some stronger to perhaps isolated severe thunderstorms capable of producing strong downbursts. HREF paintball plots show good confidence in thunderstorms developing across southern Gila County this afternoon/evening with less confidence in thunderstorms surviving into the lower deserts. Thunderstorm development into the lower deserts will have to contend with greater CIN, which will prove difficult to overcome without some good outflows. However, strong/deep and/or colliding outflows could be enough to overcome some of this inhibition to pop off a few thunderstorms across the Valley. Several 12Z HREF members indicate this possibility, showing isolated showers and thunderstorms surviving into parts of the south-central Arizona lower deserts. There is better confidence in thunderstorm development across far northern portions of Maricopa County, including the northern foothills and the Wickenburg area. Any stronger thunderstorms that were to develop across the lower deserts this evening would be capable of producing strong downbursts, which could lead to blowing dust, and locally heavy rainfall. In terms of rainfall, the 12Z HREF suggests a greater chance of seeing some locally heavy rainfall amounts across southern County where there is about a 50% chance of seeing 3 hour QPF exceed 1". Thus, isolated instances of flash flooding will be possible. .PREVIOUS DISCUSSION... Starting Thursday, guidance still favors some drying to begin across the western deserts and this should end chances for rain west of the CO River. Decent monsoon moisture should still persist across south-central and eastern Arizona, so it`s likely we will see another day of isolated to scattered afternoon convection. By Friday into Saturday, drier air is expected to filter into the rest of southern and central Arizona from the southeast and this should lower storm chances further mainly limiting any convection to higher terrain areas. At the same time, the subtropical high which is forecast to shift into the Southern Plains over the next couple of days is expected to strengthen and expand back into our region. As H5 heights rise to around 594-596dm by Saturday and we lose boundary layer moisture, temperatures will warm Friday into Saturday with highs likely reaching 110-114 degrees across the lower deserts Saturday. This may result in some areas of Major HeatRisk on Saturday and potentially on Sunday before the subtropical high begins to weaken again into early next week. There are also signs of some improving moisture again by around next Monday and if this comes to fruition it may mark another increase in monsoon activity. && .AVIATION...Updated at 2320Z. South Central Arizona including KPHX, KIWA, KSDL, and KDVT: No major aviation concerns are expected during the TAF period. Winds should follow typical diurnal trends, with a few gusts this evening in the mid-teens. There are hints of a weak outflow from distant thunderstorm activity working its way through the metro, potentially disrupting the usual winds trends but overall confidence in any wind shifts related to this feature are low at this time. An isolated shower or thunderstorm in the vicinity of the terminals cannot be completely ruled out but most activity should remain off to the north and east. SCT to BKN skies will prevail through tonight, with the lowest bases around 10k ft. Southeast California/Southwest Arizona including KIPL and KBLH: No aviation concerns are expected during the TAF period. Winds at IPL will be primarily out of the SE but a brief switch to the SW is possible early tonight. At BLH, familiar diurnal trends should prevail, with gusts this evening around 20 kts. FEW-SCT mid and high level clouds will be present through tomorrow morning, before coverage decreases by the afternoon. && .FIRE WEATHER... Isolated to scattered showers and thunderstorms are expected this afternoon across the Arizona high terrain with lower chances across the Arizona lower deserts. The primary concern with thunderstorms will continue to be strong, erratic outflow winds with up to a 50-70% chance of winds to exceed 35 mph across south- central Arizona. Locally heavy rainfall may also accompany thunderstorms, especially across southern Gila County. Thunderstorm chances continue again Thursday afternoon with gusty, erratic outflows remaining the primary concern, before a drying for the end of the week leads to decreasing thunderstorm chances, particularly across the lower elevations. Outside of thunderstorms, winds will overall favor diurnal tendencies. Min RHs will be around 20-40% and Max RHs around 40-70% over the next couple of days, with a gradual drying trend occurring for the end of the week. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...None. CA...None. && $$ DISCUSSION...Smith PREVIOUS DISCUSSION...Kuhlman AVIATION...RW FIRE WEATHER...Smith/Kuhlman
Area Forecast Discussion
National Weather Service Las Vegas NV
757 PM PDT Wed Aug 7 2024 .SYNOPSIS...Above normal temperatures will continue through the end of the week high pressure persists over the Southwestern US. Increasing moisture will help to fuel afternoon and evening convection across eastern Mohave County today with chances expanding into southern Nevada and eastern San Bernardino County on Thursday. Chances for isolated showers and thunderstorms will return each afternoon through the weekend for areas south and east of the I-15 corridor as moisture remains trapped underneath the ridge of high pressure. && .UPDATE...Other than a few showers and thunderstorms that popped up in the Mt Trumbull area as well as in the terrain around Las Vegas, it was a quiet and dry evening weather-wise across the region. Despite there being ample CAPE noted per mesoanalysis and on the 00Z Las Vegas sounding, significant mixed layer CIN and sinking dry air around 500mb has prevent any convection from popping and even cumulus struggled today. Without a significant trigger or forcing to kick things passed these limiting factors, nothing of consequence was able to develop. Models have backed off of precipitation changes for the evening and overnight hours and have adjusted the forecast accordingly. If something were able to develop, it would likely come off the complex of storms currently north of Wickenburg, AZ. Left in slight chance for showers and storms for tonight in far southern Mohave County, mainly south of Wikieup and Needles. Also something to watch for the overnight period is if an outflow develops from the convection currently in the Grand Canyon and Williams area. Some models have an outflow moving from these storms west through Mohave County and even into portions of Clark and eastern San Bernardino counties. Given the lack of convection today and that downdraft CAPE is lower than yesterday, the risk for sudden gusty winds is lower and not anticipating this solution to manifest...but with storms still on radar it is still a possibility and will need to be watched as sudden wind gusts 20 to 30 MPH would be possible if this occurred. Otherwise, it will be a dry night. Temperatures will be slightly cooler than last night`s temperatures. -Nickerson- && .PREVIOUS DISCUSSION...1245 PM PDT Wed Aug 7 2024 .SHORT TERM...through Thursday night. Some light showers pushing west through Mohave County associated with a weak disturbance will continue pushing west into San Bernardino County before gradually falling apart. These showers have generally been light with none of the gauges reporting any measurable rainfall. With the extensive cloud cover associated with this weak disturbance it will likely suppress convection this afternoon across Mohave County at least into mid-afternoon. The latest HRRR continues to show some thunderstorm development after 00z over portions of Mohave County and with some additional sunshine this afternoon it should help destabilize things and allow for convection to develop. Also starting to see some cu development over the Spring and Sheep Range, so some isolated showers and thunderstorms will be possible into this evening. With plenty of low level moisture and more sunshine we are expected to see better coverage of storms Thursday, especially across Mohave County and the higher terrain of southern Nevada. Some of the hires models are indicating the potential of strong outflow winds originating from Mohave and Coconino Counties and pushing west through the Colorado River zones and into southern Nevada and eastern San Bernardino County late Thursday afternoon. We will need to watch for the potential of gusty winds combined with areas of blowing dust. We will also need to watch for the potential of flash flooding with some of these storms as we continue to see increasing PW values. .LONG TERM...Friday through Tuesday. Continuing to watch how monsoonal moisture will interact with an inverted trough Friday and Saturday. Models remain in decent agreement that wave will shift into southern California from the Baja Peninsula while PWAT`s over 1 inch pool in areas southeast of the I-15. If forcing from the system can combine with this anomalously high moisture pool, robust convection with heavy rain and flash flooding impacts will be possible Friday and Saturday afternoons. However, models at this time keep the two features separate. While thunderstorm chances will increase and spread into portions of southeast Nevada, eastern San Bernardino County, and Mohave County, there is not a signal for a widespread high impact rain event. QPF EFIs do not paint any climatologically high rainfall areas and long term ensemble probabilities for 24 hour rainfall accumulations over 0.5 or 1.00 inches are low or non-existent. PWATs will be around 100-125% or normal, so heavy rain and flash flooding will be possible but the outlook for an extreme event is currently low. That said- will need to watch how things change as we move into the higher res model domain and for any mesoscale features that develop that could increase impacts and thunderstorm expectations. Modest instability will be in place, especially over Mohave County, so thunderstorms will be possible in general which would bring lightning, small hail, and gusty wind threats. High pressure over the Four Corners region will then slowly be broken down and pushed out of the area Sunday through the beginning of next week in response to an incoming West Coast trough. As the high retreats and the flow becomes southwest, drier air will move into the region which will result in a downward trend in thunderstorms chances each day. Sunday could still be fairly active as PWATs remain elevated but compared to Friday and Saturday, coverage and risk area should be lower and further east. Thunderstorm chances will then quickly diminish and shift eastward Monday and Tuesday. Temperatures Will remain slightly above normal Friday and Saturday before temperatures start to slowly cool each day with the incoming trough. By Tuesday afternoon, temperatures should drop to near normal for this time of the year. && .AVIATION...For Harry Reid...Breezy southeasterly winds should shift to the southwest around sunset, remaining southwesterly through most of the night. Intermittent gusts between 15 and 20 knots will last through the rest of the afternoon and evening. Winds after 06Z may strengthen due to outflows from storms over northwest Arizona, with peak gusts between 20 and 25 knots. By 12Z, winds weaken and become variable. Winds shift to the southeast once again by Thursday afternoon. Thunderstorms may also develop over high terrain around Las Vegas on Thursday afternoon, but at this time confidence is low on location and timing. Any storms that form may produce heavy rainfall and gusty erratic outflow winds. For the rest of southern Nevada, northwest Arizona and southeast California...Breezy southerly winds continue through the afternoon and overnight at all Las Vegas Valley and Colorado River Valley terminals. Winds at these sites may strengthen overnight as outflow winds from thunderstorms over Arizona reach the terminals. Overall winds should weaken in the early morning hours. Westerly winds persist through the TAF period at KDAG with gusts increasing to around 20 knots in the evening. Likewise, winds remain northerly to northwesterly at KBIH, also becoming gusty in the evening. Thunderstorms may develop near the Las Vegas Valley and Colorado River Valley on Thursday afternoon, but confidence is currently low on location and timing. Any storms that form may produce heavy rainfall and gusty erratic outflow winds. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ SHORT TERM...Gorelow LONG TERM...Nickerson AVIATION...Meltzer For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter