####018006645#### FXUS65 KVEF 131152 AFDVEF Area Forecast Discussion National Weather Service Las Vegas NV 452 AM PDT Mon Jul 13 2026 .KEY MESSAGES... * Isolated to widely scattered thunderstorms are expected today through this evening, with focus initially over the higher terrain. Gusty downburst winds and lightning are the main concerns. * Persistent monsoonal moisture will maintain shower and thunderstorm chances each day, with a transition from gusty winds to locally heavy rainfall later this week. && .DISCUSSION...Through next weekend. Convective activity on Sunday was largely limited to Arizona, with storm development over Mohave County during the late afternoon that weakened fairly quickly after sunset. Gusty winds around 45 to 55 mph resulted from the strongest storms, with outflow boundaries that made it into the Las Vegas Valley overnight. Today, expect additional development, with isolated to widely scattered showers and thunderstorms expected to initially form over the higher terrain and across Mohave County by early afternoon, drifting north- northwestward through the day around the periphery of the high pressure system located over the Four Corners Region. Per latest CAMs, instability today is expected to be roughly between 400 to 600 J/kg, locally higher, though model soundings indicate DCAPE between 1000 to 1500 J/kg, lending to a continued threat of gusty downburst winds and dry lightning, as most moisture remains entrenched in the midlevels. While the majority of convection today will largely be focused over the higher terrain and locations south of I-15 where better moisture resides, additional development along outflow boundaries cannot be ruled out. Brief downpours can be expected, especially in the mountains, with wind gusts to 45 to 55 mph accompanying the stronger cells. High-esolution ensembles indicate that convection will wane quickly after sunset, with lingering showers and gusty winds possible through late evening. The gusty winds and lightning will maintain hazardous boating conditions, especially this afternoon and evening, thus boaters on area lakes should stay weather aware and be prepared to seek shelter. High temperatures today will trend closer to normal for mid-July, though overnight lows will remain on the mild side given the increased moisture as well as potential for convective debris to linger overnight. Tuesday through the weekend, each day will see continued chances for showers and thunderstorms due to little change to the antecedent pattern and continued influx of monsoonal moisture to the region. As the atmospheric column continues to saturate, the primary concerns will gradually shift from lightning and gusty downburst winds through midweek to lightning, locally heavy rainfall and localized flooding late this week into the upcoming weekend. Temperatures will remain near and slightly above normal for the duration, with an uptick in instability expected on Tuesday - around 600 to 1000 J/kg, which could lend to some stronger storms. Additionally, as the boundary layer saturates, there will be increased potential for development on outflow boundaries, though specific convective trends each day will largely be dependent on the prior day, and whether convective debris inhibits instability, as well as where outflow boundaries may provide additional foci for development. The tropics across the eastern Pacific also remain active, with potential for moisture surges up the Gulf of California potentially reinforcing precipitable water values later this week into the weekend. Additionally, ensembles indicate an inverted trough progged to translate westward around the southern periphery of the low late week into the weekend, however, whether this feature is maintained remains in question. Regardless, the main takeaway is that we're finally in a solid monsoonal pattern, with showers and thunderstorms expected each day. Thus, those with outdoor plans should keep an eye on the forecast, and remember to seek shelter if thunderstorms threaten. && .AVIATION...For Harry Reid...For the 12Z Forecast Package...Outside of convective influences, winds will generally remain southerly to southwesterly with sustained speeds around 10-12KT through tonight. This afternoon, thunderstorms are expected to develop over higher terrain surrounding the Valley, with the best chance (20-30%) for impacts at the terminal between roughly 22Z-02Z. Erratic gusty winds and lighting strikes are the main concerns, along with brief visibility reductions due to blowing dust as well as terrain obscuration due to lower ceilings around 7-8kft. Ceilings will otherwise be SCT-BKN at 10-15kft. Thunderstorm activity will diminish late evening, with winds becoming light and variable prior to daybreak. Temperatures today will exceed 100F between 19Z-02Z, reaching a high of 104 degrees around 22Z. For the rest of southern Nevada, northwest Arizona and southeast California...For the 12Z Forecast Package...Early this morning, outflow from overnight storms is resulting in gusty up-valley winds along the Colorado River Valley from KIFP southward. These gusts will diminish by mid to late morning, though southerly to southwesterly winds around 10-12KT will continue across the region through this evening. Exceptions include the northern Owens Valley/KBIH where gusty up-valley winds to 25-30KT are expected this afternoon, and the western Mojave/KDAG where winds shift to the east late this morning and return to the west this afternoon. Scattered thunderstorms will develop over higher terrain early this afternoon, moving across lower elevations late afternoon into the evening. Erratic gusty winds and lightning are the main concerns, along with brief visibility reductions due to blowing dust. Outside of storms, ceilings will be SCT-BKN at or above 10kft, though lower ceilings to around 5-8kft are possible with storms. Winds overnight become lighter and settle to typical directional patterns. && .SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report any significant weather or impacts according to standard operating procedures. && $$ DISCUSSION/AVIATION...Phillipson For more forecast information...see us on our webpage: https://weather.gov/lasvegas or follow us on Facebook and Twitter ####018008708#### FXUS66 KMTR 131153 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 453 AM PDT Mon Jul 13 2026 ...New AVIATION, MARINE... .KEY MESSAGES... Updated at 1104 PM PDT Sun Jul 12 2026 - Monsoon moisture brings a slight chance for thunderstorms through Tuesday - Minor coastal flooding continues through Thursday morning due to large tidal swings - Warmer temperatures through Wednesday && .SHORT TERM... Issued at 1104 PM PDT Sun Jul 12 2026 (Tonight through Tuesday) You may have noticed some colorful sunrises and sunsets over the last two days. Those are being caused by monsoon moisture pushing up from the south bringing us mid level clouds. Even if it's overcast, there is enough room underneath the clouds (about 10,000 feet) for the setting sun to illuminate the bottom of these altostratus and altocumulus clouds and create the beautiful sunsets. It also helps that the low-level marine layer clouds, which typically only sit about 1,000 feet above the surface and famously ruin sunsets, were not nearly as widespread as we saw last week. So that explains the sunset, but what about the monsoon? While the word invokes many different feelings, "monsoon" actually describes a seasonal wind direction reversal. The North American Monsoon primarily impacts NW Mexico, Arizona, and New Mexico as the high summer temperatures in the desert induce thermal low pressure that brings in moist air primarily from the Gulf of California. This moisture, combined with the instability driven by high surface temperatures, often generates thunderstorms over the desert states in the Summer. In fact, Tuscon gets 52% of its rain from July-September, while we are lucky to get anything. Every once in a while the weather pattern aligns in such a way to bring some of this monsoon moisture to the Bay Area. In this case it's driven by a very strong high pressure system over the Rockies. This system is so strong that Salt Lake City just set their all time record high temperature of 109F. Since winds flow clock-wise around a high, this system is pushing the monsoon moisture from Arizona in a circular pattern towards Southern California and then northward to the Bay Area. This final push of southerly winds is enhanced by a low pressure trough over the Eastern Pacific. As the moisture moves along this conveyer belt it also moves higher in the atmosphere (humid air is less dense than dry air). This explains where the uncommon mid level clouds are coming from. While this moisture was mostly harmless today, there is a slight chance for thunderstorms through Monday. If that happens it could bring significant impacts because the high cloud base and much drier lower atmosphere means that most of the rain would evaporate before it hits the ground. When lightning strikes without much rain, wildfires can start. Thunderstorms need 3 ingredients: instability, moisture and a lifting mechanism. We have moisture, check that off the list. The instability looks pretty meager. The 00Z weather balloon from Vandenberg found the steepest lapse rates to be -7.3 C/km between 850 and 500 mb. That's not terrible, but most of the moisture is above 600mb, where it's more like -6.6 C/km, which is pretty bad. To add to the issues, there's not really an obvious trigger either. Surface heating is the typical trigger for monsoon thunderstorms in the desert, but these would be high based thunderstorms that wouldn't really feel that impact. More likely is nocturnal cloud top radiational cooling, combined with cloud base heating from surface radiation. While surface cooling makes things more stable, cloud top cooling does the opposite. If the top of the cloud gets colder and the bottom gets warmer, the instability increases due to the steeper lapse rate. The HRRR soundings also suggest that in the morning the the moisture plume will move further down towards the -10 to -20 C sweet spot where the combination of supercooled water and ice maximize particle collisions and cloud charging potential. So the best chance is probably early Monday morning. Even then it's a long shot. We're talking like somewhere between 5 and 10%. Don't be surprised if you see another good sunrise and even a few drops of rain, however. Otherwise Monday will feel pretty much like Sunday. Maybe a couple degrees warmer. && .LONG TERM... Issued at 1104 PM PDT Sun Jul 12 2026 (Tuesday night through next Sunday) The slight high based thunderstorm threat continues through at least Tuesday morning. There is some evidence that a short wave will move through that could make things more interesting, but the moisture also starts to clear by then, so we're still talking about single digit percentages. The bigger story is the heat. As the moisture clears out, so do the clouds. The full sunshine will bring temperatures into the mid 90s for several of our hotter cities, with mid 70s in the more coastal locations. That's about 5-10 degrees above normal. Strong onshore winds will arrive in the afternoon and help cool the coast quickly. Wednesday will be very similar to Tuesday, just without the thunderstorm threat. By Thursday the Eastern Pacific trough that helped pump the moisture earlier in the week will arrive and bring a weak cold front, kicking off a late week cooling trend. A quick note on the tropics. As the El Nino Advisory continues, the National Hurricane Center is currently tracking 5 disturbances in the Central and Eastern Pacific. While these systems rarely impact California directly, the residual moisture can bring impacts similar to the monsoon with high based thunderstorms. Refer to Tropical Storm Fausto, the 2020 lightning outbreak and subsequent wildfires for a good example of this. Additionally, the ocean swell generated from these storms can bring hazardous beach conditions. While there is no immediate threat, there is a high chance for an active hurricane season in the Pacific and we'll be watching closely for these impacts. && .AVIATION... (12Z TAFS) Issued at 448 AM PDT Mon Jul 13 2026 VFR is expected to prevail through the forecast period with the exception of KHAF that may toggle between VFR and IFR/LIFR through mid-morning. Slight chance of low end MVFR cigs early Wednesday morning for terminals on the immediate coast. Vicinity of SFO...VFR, with breezy onshore flow this afternoon and slight chance of low end MVFR cigs early Wednesday morning. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...VFR is expected to prevail through the TAF period with a slight chance of low end MVFR ceilings early Wednesday morning. && .MARINE... (Today through Saturday) Issued at 448 AM PDT Mon Jul 13 2026 Moderate to fresh north-northwest winds across the northern outer waters continue with hazardous conditions, along with moderate northwest swell. Northerly winds over the coastal and outer waters become fresh to strong mid to late week, with near gale force gusts. Expect building seas in response to the increasing winds and long period southerly swell late week into next weekend. && .FIRE WEATHER... Issued at 448 AM PDT Mon Jul 13 2026 Warming temperatures this will cause fuel moistures to plummet for the first half of the week. At the same time we are tracking monsoonal moisture moving across the area and any threat of dry thunderstorms today and Tuesday. While dry thunderstorms have a 10% or less chance of development, any strike can start a fire. Not to mention, in and around active thunderstorms, winds can become gusty and erratic. For more information on the thunderstorm threat, see discussion above. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...Coastal Flood Advisory until 4 AM PDT Thursday for CAZ006-506- 508. Coastal Flood Advisory until 4 AM PDT Wednesday for CAZ505-509- 529-530. PZ...Small Craft Advisory from 3 PM Tuesday to 3 PM PDT Wednesday for Pt Arena to Pt Reyes 0-10 nm. Small Craft Advisory until 3 PM PDT Wednesday for Pt Arena to Pt Reyes 10-60 NM. && $$ SHORT TERM...Flynn LONG TERM....Flynn AVIATION...JM MARINE...JM Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, X, and YouTube at: www.facebook.com/nwsbayarea x.com/nwsbayarea www.youtube.com/nwsbayarea ####018005391#### FXUS64 KSJT 131153 AFDSJT Area Forecast Discussion National Weather Service San Angelo TX 653 AM CDT Mon Jul 13 2026 ...New AVIATION... .KEY MESSAGES... - Scattered to numerous showers and thunderstorms today through Thursday and into Thursday night. Locally heavy rainfall could bring an attendant threat for flooding and flash flooding, especially across the southern and southwest part of our area. && .SHORT TERM... (Today and tonight) Issued at 316 AM CDT Mon Jul 13 2026 A strong upper ridge will be centered over the northern Plains and upper Midwest through tonight. Beneath the ridge, a very moist and warm airmass will be in place across the region again today, with precipitable water (PWAT) values ranging between 1.5 and 2+ inches. Scattered to numerous showers and thunderstorms are expected today into tonight, with the best coverage south of Interstate 20. Given weak flow aloft, showers and thunderstorms will be slow moving and efficient rain producers. Much of the area, generally south of Interstate 20 is in a slight risk for excessive rainfall through tonight. While widespread flooding is not anticipated, the potential exists for isolated flash flooding, especially in low lying and poor drainage areas. Temperatures will be considerably cooler today, due to more cloud cover and precipitation around, with highs ranging from the lower 90s across the Big Country, to the mid and upper 80s elsewhere. Lows tonight will be in the upper 60s and lower 70s. && .LONG TERM... (Tuesday through next Monday) Issued at 1210 AM CDT Mon Jul 13 2026 The main focus Tuesday through Thursday will be on the potential for heavy rainfall and flooding/flash flooding. On Tuesday an elongated, anomalously strong upper ridge will extend from the central Rockies east across the Midwest, then east-southeast to the mid- Atlantic Coast. To the south of this ridge, an upper low will shift west to the lower Mississippi Valley, and there are indications for another low to develop by evening over the Texas Hill Country. The coverage looks uncertain for showers and thunderstorms in our area Tuesday. The airmass will be very moist (precipitable water values 1.5 to 2 inches) and uncapped, and will likely have leftover outflow boundaries from Monday convection. At this time, leaning toward a scenario with scattered showers and thunderstorms, with our and southern counties more favored for higher coverage. The aforementioned Texas upper low is forecast to move west- northwest along or just south of I-10 Tuesday night and Wednesday, to near or just north of the Big Bend area by Thursday. This track and placement would provide more favorable lift with better upper support over our area. Should have more organized/widespread convection over our southern and central counties, perhaps with a few rounds of activity. Seeing indications of a weak low-level jet developing Wednesday night and a little stronger low-level jet Thursday night. This will help to provide an influx of low-level moisture, and precipitable water values are forecast to be 1.5 to 1.9 inches. Taking all of these factors into consideration, have increased concerns for flooding/flash flooding in a fairly broad time frame, developing Tuesday night/Wednesday and continuing Thursday into Thursday night. The main focus looks to be over the southern and central parts of our area. With the above mentioned scenario and increased cloud cover, daytime temperatures Tuesday through Thursday should be limited to mostly the 80s for highs. The upper low is progged to move slowly west-southwest into far northern Mexico by Friday night into Saturday. With a slower progression now indicated, the chance of showers and thunderstorms will linger in at least our western counties on Friday. The weekend will trend warmer and drier with gradually building heights aloft. Medium range models differ on placement/repositioning of an upper level ridge, and its proximity to our area. The forecast at this time has highs ranging from the upper 80s/lower 90s in our southern counties, to the mid 90s in the Big Country north of I-20 Saturday, and mid to upper 90s Sunday. && .AVIATION... (12Z TAFS) Issued at 648 AM CDT Mon Jul 13 2026 Stratus with patchy MVFR ceilings will affect the southern terminals through mid to late morning. Ceilings will scatter out/lift to VFR by the late morning. Another round of convection is expected today and will maintain PROB30 groups for the terminals through this afternoon. Could see additional convection overnight but due to uncertainty, will not mention at this time. Winds will remain light the next 24 hours. && .PRELIMINARY POINT TEMPS/POPS... Abilene 90 70 87 69 / 50 20 50 30 San Angelo 88 69 86 67 / 60 40 70 50 Junction 89 70 86 67 / 50 50 70 60 Brownwood 88 69 85 68 / 60 30 60 40 Sweetwater 90 70 88 68 / 40 20 60 20 Ozona 86 69 84 66 / 60 50 90 70 Brady 87 69 83 67 / 60 50 70 50 && .SJT WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...24 LONG TERM....19 AVIATION...24 ####018005269#### FXUS64 KSHV 131154 AFDSHV Area Forecast Discussion National Weather Service Shreveport LA 654 AM CDT Mon Jul 13 2026 ...New AVIATION... .KEY MESSAGES... Issued at 107 AM CDT Mon Jul 13 2026 - Additional waves of showers and thunderstorms will be possible throughout the first half of the week. Flooding may become a concern for areas along and south of the I-20 corridor of east Texas. - A return to quieter and hotter conditions is expected late this week and into the weekend. && .DISCUSSION... Issued at 107 AM CDT Mon Jul 13 2026 Have elected to keep or slightly increase PoPs overnight across the ArkLaTex, as remnant rainfall slowly treks eastward across east Texas and south out of southern Arkansas. With limited steering, the possibility remains for such overnight rain to stall, leading to possible isolated flash flooding. The 00Z 3 km NAM and 02Z HRRR are hinting at a more organized complex developing along the Red River Valley on the Texas-Oklahoma state line late overnight towards daybreak, swinging south across our east Texas counties into the morning. Beyond that, solutions diverge, with the NAM being quieter and the HRRR more active. Today's showers and storms will depend very much on what the surface boundary to our north does. Those recent runs of the HRRR suggest that the boundary will start to get moving again, eventually positioning itself in the neighborhood of the I-30 to I-20 corridors, containing the moisture for potential additional convection to the south. Thus, further impulses of moisture propagating across east Texas will keep largely along and south of the US-84 corridor, crossing Toledo Bend into west central Louisiana. By Tuesday, the occasionally stationary surface boundary pretending to be a cold front will still be very much present over the ArkLaTex, and ensemble guidance is hinting it may inch just far enough to the north to open the door to more widespread convective activity, with defined waves sweeping from south to north if surface steering is pronounced enough. Through Tuesday, rainfall accumulations of 1-3 inches are expected, with locally higher amounts possible, and the greatest accumulation expected across deep east Texas. Confidence in coverage and duration does not merit a Flood Watch as of this writing, but isolated flash flooding will remain possible throughout. Among the challenges with this forecast is the unusual behavior of the synoptic scale features for this time of year. Recent solutions have been based on the positively tiled trough over the Appalachians and its attendant surface boundary as our primary forcing mechanism. The latest GFS illustrates this first trough closing around its low pressure center and retrograding west by midweek, potentially forming a new inverted trough over Texas, sustaining chances for additional rainfall through Wednesday afternoon. Beyond that, the low should retrograde further west, making way for mostly dry conditions for the remainder of the forecast period. Highs in the upper 80s to lower 90s early in the week will rebound into the middle 90s by Thursday and beyond. Overnight lows in the 70s will continue throughout. /26/ && .AVIATION... (12Z TAFS) Issued at 649 AM CDT Mon Jul 13 2026 For the 13/12Z TAF period, a mixed bag of flight categories to begin the TAF period, and do expect a gradual deterioration of conditions today as low stratus MVFR/IFR cigs will eventually overspread most terminals. This will occur as convection is also expected to regenerate and expand once again as heating increases throughout the day and a frontal bndry continues to bisect our airspace. Therefore, have included VCSH/VCTS at all sites during much of today and will likely need to prevail TSRA at some point in future TAF cycles as confidence in timing increases. Otherwise, look for cigs to gradually lift back to MVFR/VFR toward midday, albeit low VFR in most cases with increasing convection. Light and variable winds this morning will generally prevail throughout the period with the bndry lingering as speeds average around 5 kts or less with higher gusts invof of convection. /19/ && .SPOTTER INFORMATION STATEMENT... Issued at 107 AM CDT Mon Jul 13 2026 Limited spotter activation may be requested across the region, particularly for flooding concerns in deep east Texas. Even if activation is not locally requested, any reports of hazardous weather to the National Weather Service are appreciated. /26/ && .PRELIMINARY POINT TEMPS/POPS... SHV 85 72 87 72 / 70 20 50 20 MLU 89 73 90 72 / 50 20 50 30 DEQ 89 70 90 70 / 30 10 20 20 TXK 90 72 91 72 / 40 10 30 20 ELD 89 70 89 70 / 30 20 40 40 TYR 86 72 88 71 / 80 30 50 20 GGG 85 71 87 70 / 80 30 50 20 LFK 84 70 84 70 / 80 60 70 20 && .SHV WATCHES/WARNINGS/ADVISORIES... AR...None. LA...None. OK...None. TX...None. && $$ DISCUSSION...26 AVIATION...19