####018003998#### FXUS64 KCRP 180550 AFDCRP Area Forecast Discussion National Weather Service Corpus Christi TX 1250 AM CDT Tue Aug 18 2026 ...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER... .KEY MESSAGES... Issued at 1246 AM CDT Tue Aug 18 2026 - Moderate to major risk of heat-related impacts through next week with peak afternoon heat indices around 110 - Monitoring daily elevated fire weather potential over the Brush Country through the week and into next week && .DISCUSSION... Issued at 1246 AM CDT Tue Aug 18 2026 Little overall change is expected through the period as only subtle shifts occur in the center position of the mid-level high. South Texas will remain beneath the influence of the ridge with the center over the Desert SW, maintaining hot and predominately dry conditions. Very low rain chances will remain possible along the sea breeze each afternoon, though measurable rainfall is not anticipated. Toward the end of the forecast period, PVA rounding the periphery of the high may provide somewhat better support for convection and a slight increase in rain chances. Temperatures will remain largely unchanged, with afternoon highs generally ranging from the 90s across the Coastal Bend to around 100- 105 degrees across the Brush Country and the Rio Grande Plains. Overnight lows will generally remain in the mid 70s to lower 80s. Peak heat indices of 105 to around 110 are expected each afternoon, maintaining moderate to major HeatRisk across much of South Texas. Pockets of extreme HeatRisk may develop across portions of the Brush Country this weekend. With little relief from the heat expected, continued heat safety precautions will be necessary throughout the period. && .AVIATION... (06Z TAFS) Issued at 1246 AM CDT Tue Aug 18 2026 VFR CIGS/Vis noted at issuance time, but confidence isn't great on how widespread MVFR will get overnight. Some guidance suggests similar to last night while other guidance is much more favorable in terms of flight categories. Will lean toward similar conditions to last night as in the big picture overall conditions have not changed much, so unsure why it'd be better than last night. && .MARINE... Issued at 1246 AM CDT Tue Aug 18 2026 Persistent onshore flow will remain generally gentle to moderate (BF 3-4), with occasional fresh (BF-5) flow possible during the late afternoon and nighttime hours. Seas should remain relatively steady around 2-3 ft with no significant marine hazards anticipated. Rain chances will remain very low through the weekend, with a potential increase early next week. && .FIRE WEATHER... Issued at 1246 AM CDT Tue Aug 18 2026 Elevated fire weather concerns will continue, particularly across the Brush Country, as hot and dry conditions persist. Minimum RH values will briefly fall into the mid 20s for several hours each afternoon across the Brush Country. ERC values remain within the 70th-89th percentile, while maximum RFTI values remain around 2. Although widespread critical fire weather conditions are not anticipated, the combination of low afternoon humidity, increasingly dry fuels, and hot temperatures will maintain an elevated fire weather risk through much of the period. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 95 77 96 78 / 0 0 0 0 Victoria 99 75 99 76 / 10 0 10 0 Laredo 103 77 104 78 / 0 0 0 0 Alice 101 73 101 75 / 10 0 10 0 Rockport 92 80 92 82 / 0 0 0 0 Cotulla 103 77 105 78 / 0 0 0 0 Kingsville 98 74 99 76 / 10 0 10 0 Navy Corpus 90 81 90 82 / 0 0 0 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ DISCUSSION...BF/80 AVIATION...PH/83 ####018003048#### FXUS64 KMRX 180551 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 151 AM EDT Tue Aug 18 2026 ...New DISCUSSION, AVIATION... .KEY MESSAGES... Updated at 144 AM EDT Tue Aug 18 2026 - Regular warm to hot August temperatures to continue, with on and off rain and thunderstorm chances returning Thursday and continuing into the weekend. && .DISCUSSION... Issued at 144 AM EDT Tue Aug 18 2026 We will see some minor relief next two days, with a return to typical summertime temperatures and a drop in the overall PWAT for the atmosphere. PWATs drop down to 1.2" or so, which is just above the 25th percentile for August, a time of year in which we're at the climatological maximum for vertical water content. Since the upper heights are otherwise fairly flat, we only return to near or slightly above typical highs for August, so not sure how much jumping for joy our anti-humidity cabal will be doing this week. We will also likely remain dry the next two days, with surface ridging overhead and no obvious discernible source of forcing to get us storm development. Unfortunately we get another shortwave to arrive on Thursday, which has the side effect of re-introducing more rain and storm chances to our region, with higher chances in the north. 30 to 40 knots of shear exist Thursday into Thursday night, GFS and long range RRFS both depict a dying storm cluster early on Thursday to our west, then a lull likely from cloud debris, then potential for scattered PM and late night thunderstorms. Whether or not that scenario comes to fruition is an unknown. CAPE is a bit of a question, though depending on how the morning goes we may realize more CAPE than the low-biased GFS depicts. Shear profiles are more favorable for strong winds. Something to watch, anyways. Scattered rain and storms then will likely remain in the forecast into the weekend, as a series of shortwaves occur before a large trough digs into the Great Lakes and then the northeastern US Sunday into Monday. && .AVIATION... (06Z TAFS) Issued at 144 AM EDT Tue Aug 18 2026 The threat for precip/lightning from earlier is well over. Low CIG and VSBY possible through the early morning hours, with the worst conditions most likely at TRI. CHA may walk the line of VFR and MVFR. Once CIG break and lift later on this morning, VFR will dominate with dry weather anticipated under strengthening surface high pressure. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 93 69 95 74 / 0 0 0 20 Knoxville McGhee Tyson Airport, TN 89 68 92 71 / 10 0 0 10 Oak Ridge, TN 89 66 91 71 / 0 0 0 20 Tri Cities Airport, TN 85 64 88 67 / 10 0 0 10 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ DISCUSSION...Wellington AVIATION...KS ####018007299#### FXUS61 KBOX 180551 AFDBOX Area Forecast Discussion National Weather Service Boston/Norton MA 151 AM EDT Tue Aug 18 2026 .WHAT HAS CHANGED... Aviation section updated for 06z TAFs. && .KEY MESSAGES... - Fair and less humid Tuesday with gradual clearing. A high risk of rip currents develops across east-facing beaches by Tuesday afternoon. - No washouts expected, though several opportunities for showers return from mid to late week. && .DISCUSSION... KEY MESSAGE 1...Fair and less humid Tuesday with gradual clearing. A high risk of rip currents develops across east-facing beaches by Tuesday afternoon. Gradual clearing develops from W to E Tuesday as low pressure slowly pulls away from the region. Guidance shows areas of low clouds and fog lingering for much of the day across coastal areas with the help of cyclonic onshore flow. Thus, expecting high temperatures to stay in the lower to mid 70s for coastal areas, and perhaps even the upper 60s for the outer Cape. It will be quite humid closer to the coast with onshore flow advecting moisture inland. Elsewhere, it will be drier as the flow turns to the NW through the day. Further inland, it looks to be a warmer and drier day with highs in the low to mid 80s. Heat index values climb into the upper 80s to near 90 for a time Tuesday afternoon. For those heading to the beach Tuesday afternoon, a Rip Current Statement is in effect for east-facing beaches Tuesday. Those heading to the beach should remain aware of local conditions and check with lifeguards or beach staff regarding rip current risks at their specific location. KEY MESSAGE 2...No washouts expected, though several opportunities for showers return from mid to late week. Generally zonal flow aloft prevails Wednesday while an upper level low tracks well north across the Hudson Bay. Conditions are likely to stay dry during the day with temperatures in the low to mid 80s. A weak piece of shortwave energy shifts in from the west later Wednesday. While the better forcing remains further north and west, there is a low probability for an isolated shower in western MA Wednesday night. Another shortwave in the flow moves through Thursday accompanied by better ascent and plume of above normal moisture to support showers. There is still some uncertainty across guidance with the track of the wave. The ECMWF (ens and deterministic) leans toward a more southern track with the higher ensemble probabilities (60-80%) for any rain accumulation extending across the south coast to southeast MA, and Cape/Islands. The GEFS/GFS has shown a wider footprint of showers with similar probabilities across all of southern New England. Any amounts are likely to range from a trace to a few tenths of an inch. We'll be in a post-frontal airmass Friday resulting in slightly cooler temperatures in the mid 70s to low 80s and a downtick in humidity. The eastern coastal areas will likely end up on the cooler end of that temperature range given the easterly onshore flow. High pressure builds in from the west bringing dry conditions to most of the region. However, there are indications across model guidance of a boundary stalling off the east coast with a series of embedded shortwaves riding that boundary Friday through the weekend. This may bring periodic chances for showers, perhaps some thunderstorms if the waves align with diurnal heating. The higher risk for showers will the for south coast extending to Cape Cod/Islands. && .AVIATION /06Z TUESDAY THROUGH SATURDAY/... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through 12z...Moderate confidence Pockets of IFR are continuing to develop across the region, with some areas reaching LIFR. Notably, coastal terminals have hit this sooner. Light E to NE winds continue over more coastal terminals with calm conditions persisting over the interior terminals. Tuesday...Moderate confidence (ceilings) MVFR to IFR conditions to start, with improvement to VFR from west to east between 17Z and 20Z. Improvements for terminals further east may be slower and may only top out to MVFR based on guidance, though VFR by 00z is a possibility for Cape/Islands terminals. Light N winds become more NW during the afternoon for the interior terminals, while onshore NE/E winds continues for eastern terminals, generally at 5-10 kt. Higher winds above 10 kt are possible for ACK. Tuesday Night...Moderate confidence. VFR across the interior, though MVFR towards the Cape/Islands, along with RI terminals, depending on how thick cloud cover remains. Otherwise, SCT to FEW at lower ceilings. ACK could see return of IFR conditions. Light NW to SW winds less than 10 kt with patchy fog possible. Wednesday...High confidence. VFR. WSW winds over much of the region, more SSW over the coastal areas all at 5-10 kt. KBOS Terminal...Moderate confidence. LIFR visby possible periodically early this morning through at least 08z. Exact timing of improvements to VFR lower confidence, but more likely between 16-19Z. SCT MVFR decks possible through the afternoon. Winds NE becoming E in the afternoon 7-10 kts. KBDL Terminal...Moderate confidence. MVFR conditions have just moved in to the terminal and are expected to continue through the rest of tonight into the mornings hours. Periods of IFR cannot be entirely ruled out for the early morning hours. Chance of fog remains. Outlook /Wednesday through Saturday/... Wednesday through Wednesday Night: VFR. Thursday: VFR. Chance SHRA. Thursday Night through Friday: VFR. Slight chance SHRA. Friday Night: Mainly VFR, with local MVFR possible. Slight chance SHRA. Saturday: VFR. Chance SHRA. && .MARINE... Forecaster Confidence Levels... Low - less than 30 percent. Moderate - 30 to 60 percent. High - greater than 60 percent. Through Tuesday Night...Moderate confidence. SCA conditions subside Tuesday as low pressure shifts farther east. Seas subside to 2 to 4 ft, with light northerly to north- northwest winds generally less than 15 kt. High risk of rip currents for east-facing beaches across E Massachusetts as well as the Cape and Nantucket. Outlook /Wednesday through Saturday/... Wednesday through Wednesday Night: Winds less than 25 kt. Thursday: Winds less than 25 kt. Slight chance of rain showers. Thursday Night: Winds less than 25 kt. Chance of rain showers, slight chance of thunderstorms. Friday through Saturday: Winds less than 25 kt. Chance of rain showers. && .BOX WATCHES/WARNINGS/ADVISORIES... CT...None. MA...High Risk for Rip Currents from 8 AM EDT this morning through this evening for MAZ007-015-016-019-022-024. RI...None. MARINE...Small Craft Advisory until 2 AM EDT early this morning for ANZ254>256. && $$ DISCUSSION...Mensch/FT AVIATION...Hrencecin/Mensch/FT MARINE...FT ####018006387#### FXUS65 KCYS 180552 AFDCYS Area Forecast Discussion National Weather Service Cheyenne WY 1150 PM MDT Mon Aug 17 2026 .KEY MESSAGES... - There is a Marginal Risk (Level 1 of 5) of severe weather for the Nebraska Panhandle today. - There is another Marginal Risk (Level 1 of 5) for Tuesday afternoon covering the majority of the forecast area. - Seasonable temperatures and chances for scattered PM showers and thunderstorms continue through Wednesday. - Warmer and drier weather will return to the area Thursday and Friday. && .SHORT TERM /THROUGH TUESDAY NIGHT/... Issued at 155 PM MDT Mon Aug 17 2026 As the upper-level ridge attempts to strengthen throughout the day, a low pressure system will be moving across the Canadian Providences. The trough created by the system will be moving the Intermountain west Monday and Tuesday. For today our westerly flow will continue to dry out the lower levels along and east of the I-25 corridor severely limiting todays shower potential for Southeast Wyoming. The Nebraska Panhandle will be slightly capped through the morning allowing for enhanced moisture retention compared to Wyoming. As the dryline pushes eastward, it will lead to forcing for western Nebraska. With residual moisture and support from 500mb vorticity maxima, showers and storms are anticipated to develop this afternoon. MLCAPE values increase this afternoon to around 1000 to 1500 J/kg in western Nebraska. Forecast soundings from the RAP suggest stout Inverted-V signatures west of the dryline across southeast Wyoming, with more favorable severe soundings in western Nebraska, though still will substantial DCAPE values. The Storm Prediction Center (SPC) has covered much of the Nebraska Panhandle in a Marginal Risk (level 1 of 5) mostly for severe wind and the possibility of hail greater than 1 inch. Multiple lobes of 500mb vorticity continue to trek across the region Tuesday afternoon into the overnight hours, due to increased vorticity from the proximity of the upper-level trough. The slightly compressed height gradient will lead to more shear across the region, with strong 700mb warm air advection allowing increased forcing. The terrain-induced dryline will retreat westward Tuesday afternoon, allowing stronger moisture advection along and east of the Laramie Range, setting up another day with increased precipitation chances. With stronger forcing, increased moisture, and increased shear in the region, storms will have a better chance of becoming severe on Tuesday, with large hail and damaging winds possible once more. SPC has expanded the Marginal risk (level 1 out of 5) to include majority of the forecast area. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Issued at 155 PM MDT Mon Aug 17 2026 Global model guidance has trended faster in amplifying the upper level ridge over the western CONUS and transitioning our area to a northwest flow pattern. As a result of this trend, the shortwave trough riding on the back edge of the zonal flow pattern has accelerated from a Wednesday PM arrival to a Wednesday AM arrival. Drier air and more subsidence in the wake of this feature has modified the forecast for Wednesday somewhat by pushing the moisture out faster. What looked like a potentially potent severe weather setup yesterday has now been nudged further to the southeast, such that storm chances are reduced for the majority of the area. There is still the potential for a few isolated strong to severe storms in the eastern and southeastern portions of the forecast area, but look for a drier day than previously anticipated along and west of a Cheyenne to Harrison line. This also accelerates the onset of the next round of hot temperatures as ridging builds in to our west. Expect highs to climb a few degrees above average on Wednesday, then 5 to 10 degrees above for Thursday through Saturday. We probably won't be totally dry on Thursday and Friday, but expect PM convection to be much more limited and likely confined to areas in or near the higher terrain of southern Wyoming. Attention will shift back to fire weather during this period as well. Westerly winds moving into the area behind Wednesday's shortwave trough will lead to at least elevated, if not critical, fire weather conditions along and west of the Laramie Range. The winds appear a little lighter for Thursday and Friday, but model guidance has been consistently too low on winds in Carbon and Albany counties lately. The upper level ridge will very gradually shift eastward over the course of the week, sliding east of the Four Corners by the weekend. This will allow a fresh tap of monsoon moisture to be pulled northward into the Great Basin and Four Corners states, eventually working its way over the top of the ridge and into our area. As a result, look for increased coverage of PM shower and thunderstorm activity for the weekend with temperatures remaining about 5 to 10 degrees above seasonal averages. && .AVIATION /06Z TAFS THROUGH 06Z WEDNESDAY/... Issued at 1150 PM MDT Mon Aug 17 2026 An isolated thunderstorm will mainly impact KAIA late tonight as an upper level jet max moves into the region. Otherwise, other areas will see increasing cloudiness and VCSH through sunrise. Multiple rounds of showers and thunderstorms expected across all southeast Wyoming and western Nebraska terminals on Tuesday as a backdoor cold front slowly moves southwest across the high plains. HAZARDS/WEATHER TRENDS: VCTS for KBFF and KAIA should clear out of the area by 07z, with VFR conditions prevailing through 21z. Some brief gusty winds are possible with any thunderstorm outflow, but magnitude and timing are low confidence. For Tuesday, added PROB30 groups for nearly all terminals with multiple rounds of showers and thunderstorms possible with a good chance of periods of MVFR conditions. Will nail down the timing by 18z Tuesday once the event(s) get closer. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...None. NE...None. && $$ SHORT TERM...MM LONG TERM...MN AVIATION...TJT ####018003310#### FXUS64 KLCH 180553 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1253 AM CDT Tue Aug 18 2026 ...New DISCUSSION, AVIATION, MARINE, FIRE WEATHER... .KEY MESSAGES... - A Heat Advisory will be in effect from CenLA to southern Acadiana from 12PM to 8PM. - An upper level ridge will remain in place keeping afternoon highs above normal. - No appreciable rainfall accumulation is expected through the next seven days. && .DISCUSSION... (Today through Monday) Issued at 1248 AM CDT Tue Aug 18 2026 Little to no overall change in the pattern. At the surface, high pressure is centered over the Gulf, where it is expected to meander for several days. This will maintain southerly to southwesterly flow, keeping moisture in place. Aloft, a broad ridge stretching across the Southwest through the Gulf Coast states will persist. As has been the story for the last few days, above average temperatures will continue. A combination of high temperatures and elevated dewpoints has led to another Heat Advisory this afternoon and evening across the eastern third of the CWA. Drier air mixing down will help keep heat index values lower across the western CWA, keeping them below hazard criteria. While confidence in an area wide Heat Advisory remains low, heat precautions should still be taken. Going into the middle to latter half of the week, the upper ridge will be shunted slightly westward as a broad trough sags southward into the Deep South. While this feature will only bring a few degrees of relief, it could trigger isolated convection, especially along the coast and across eastern portions of the CWA. Any relief will be short lived, however, as guidance indicates the ridge building back over the region from the weekend into early next week. && .AVIATION... (06Z TAFS) Issued at 1248 AM CDT Tue Aug 18 2026 VFR conditions ongoing and expected to prevail through this TAF cycle with mainly light variable to SWrly winds. && .MARINE... Issued at 1248 AM CDT Tue Aug 18 2026 Surface high pressure over the northwest Gulf will keep winds light out of the southwest through the forecast period, generally no more than 5-12 kt, with seas around 1-2 ft. High pressure aloft will keep rain chances near zero through much of the week. Some isolated shower activity may return by this weekend, with greater chances further east. && .FIRE WEATHER... Issued at 1248 AM CDT Tue Aug 18 2026 Hot conditions are expected across the CWA through the forecast period, with POPs nearly zero through midweek. Daily RH minimum values will range from 35 to 50 percent across the area this week. Surface high pressure over the northern Gulf will keep winds light out of the southwest through the period. With very little to no rainfall expected for the duration of this forecast period, worsening drought and fire weather conditions could be possible. && .LCH WATCHES/WARNINGS/ADVISORIES... LA...Heat Advisory from noon today to 8 PM CDT this evening for LAZ028-029-032-033-044-045-055-143-152>154-243-252>254. TX...None. GM...None. && $$ PUBLIC/FIRE/MARINE...87 AVIATION...87