####018003570#### FXUS63 KFGF 131130 AFDFGF Area Forecast Discussion National Weather Service Grand Forks ND 630 AM CDT Mon May 13 2024 .KEY MESSAGES... - Areas of frost are expected this morning across portions of northwest Minnesota and northeastern North Dakota. Temperatures in the low to mid 30s are possible. - Patchy smoke remains in place across the area through much of the day ahead of our next system that moves into the region tonight into Tuesday. && .UPDATE... Issued at 630 AM CDT Mon May 13 2024 Coldest temperatures this morning are near Devils Lake and generally along the International Border, where low 30s have been observed. A few cold spots have been noted in northwest Minnesota as well, with temps generally in the middle 30s. Lingering surface smoke is bringing visibility down to 4 miles around Fergus Falls and Wadena, with mid to upper level smoke elsewhere not impacting visibility. && .DISCUSSION... Issued at 354 AM CDT Mon May 13 2024 An active pattern prevails through much of this week as several shortwaves traverse the region. Upper flow from 500mb up to 300mb remains rather progressive, with a substantially more amplified pattern from 500mb down to 700mb. For today, dry air remains in place across the area, along with low relative humidity. RH values could fall into the lower 20 percent range once more in some areas; however, winds will be relatively light, generally in the range of 7 to 12 mph. A slow moving shortwave will bring rain chances into the region starting early Tuesday, then persist through the day on Wednesday before tapering off Thursday. A good portion of the area has a 30 percent chance to see 0.50 inch of rain from this first system. An isolated thunderstorm is possible; however, there is little, if any, support for strong storms. A second system is being highlighted by ensemble clusters starting late Thursday. The pattern is very similar, as a weak H7 trough traverses the area. This system has a 20 percent chance of bringing 0.50 inch of rain to portions of the region, with low confidence in the exact location. A few thunderstorms are possible, with the best chances along the ND/SD border. Heading into the weekend, another upper low is showing up in several sources of guidance; however, confidence is low as ensemble members show a good bit of disagreement. In general, the pattern remains somewhat close to what we are expecting through much of next week, with chances for showers and thunderstorms expected. For the weekend, there seems to be a more favorable setup for perhaps a stronger storm or two. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 630 AM CDT Mon May 13 2024 VFR conditions prevail at all TAF sites through the period. Lingering near-surface smoke is bringing minimal restrictions to visibility, mainly to KFAR this morning. Surface smoke is expected to lift this morning as mixing takes shape. Mid level smoke remains likely through much of the day, especially for KBJI and KTVF. Winds will slowly shift to the east through the day, generally remaining in the 7 to 12 knot range. && .FGF WATCHES/WARNINGS/ADVISORIES... ND...Frost Advisory until 8 AM CDT this morning for NDZ006>008-016- 054. MN...Frost Advisory until 8 AM CDT this morning for MNZ004>009- 013>017. && $$ UPDATE...Lynch DISCUSSION...Lynch AVIATION...Lynch ####018004876#### FXUS63 KDMX 131130 AFDDMX Area Forecast Discussion National Weather Service Des Moines IA 630 AM CDT Mon May 13 2024 ...Updated for the 12z Aviation Discussion... .KEY MESSAGES... * Showers and weak thunderstorms will continue through Monday across portions of central and southern Iowa. Some lingers SE into Tuesday. No real opportunity for strong/severe. * Brief reprieve Tuesday into Wednesday before additional showers/thunder move through Wednesday PM into Thursday - Severe risk low. * Cooler throughout the week - Highs mid 60s to mid 70s, lows mid 40s to 50s. && .DISCUSSION... Issued at 234 AM CDT Mon May 13 2024 Upper level trough continues to churn across western and central Kansas early this morning, as seen on various GOES 16 water vapor products, bringing with it increased lift and precipitation coverage locally. Much of the precipitation to this point has been driven by waves of low-mid level lift associated with theta-e advection. With little to latch onto in terms of MUCAPE or wind profiles, activity has been limited to periodic thunder and brief periods of moderate rainfall. Greatest precipitation amounts have been along/south of Interstate 80, with many a half inch or less. A hyper-local precipitation max of around 3 inches has been seen just west of Indianola, but came over the period of a few hours, limiting local issues. Showers and occasional thunder coverage is expected to increase through the morning and into the afternoon as deeper lift associated with the upper trough begins to move into the area. With its track generally eastward and dry air encroaching from the north, there will be a sharp gradient/cut-off to precipitation drifting southward out of northern Iowa through the day. Weak SB/MUCAPE and muted flow through the column (generally under 20 kts) will yield predominantly light to moderate slow moving areas of showers/thunder. Hi-res/CAM guidance suggests relatively widespread amounts of around 1 to 1.5 inches along/south of Interstate 80. Locally higher amounts for areas that experience "stronger" convection and/or multiple rounds of it may see totals in excess of 2 to 2.5 inches, with it occurring over a number of hours though, hydrologic issues are not expected. This activity may linger in southeast areas of the state into Tuesday before briefly drying out. Of casual note, there may be hints of smoke in the air at times today across the state as northerly winds help usher in smoke from Canadian wild fires. This is not expected to be highly impactful aside from occasional smells or light haze with modeled near-surface concentrations on the low end. By Wednesday afternoon/evening, the next opportunity for showers and storms will begin to move in as southern and northern stream shortwave energy encroaches. Synoptic runs have continued the recent trend of poor/no phasing of the waves, resulting in disjointed areas of precipitation. For the most part, this continues to put Iowa between the two shortwave paths and may only result in light precipitation amounts. Regardless, the strong/severe threat remains very low. Deterministic guidance has come into better agreement on the large scale pattern to end the week and into the weekend, but continue to depict timing differences of passing compact shortwaves within. Divergence then accelerates by Sunday. This continues to result in prolonged low-end precipitation chances within NBM and the going public forecast. At that time window, remarkably difficult to pin down meaningful (and skillful) changes to PoPs. Throughout the week, expect temperatures to be near-normal for the most part with forecast highs ranging from the mid 60s to mid 70s. The cool and generally wet conditions should continue to eat away at lingering drought areas. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 626 AM CDT Mon May 13 2024 Conditions will range from predominantly VFR for northern sites KFOD/KMCW/KALO to possible MVFR at KDSM to likely MVFR/IFR at KOTM, driven by ceilings. Aside from KMCW, all other TAF sites will battle at least some VCSH throughout the day, drying out from NW to SE during the TAF period. TSRA potential is relatively so, so have tried to limit mentions to most likely windows. Have also kept ceilings broadly up compared to guidance, with current observations higher than guidance suggests in areas of eastern Nebraska and northwest Missouri. Winds will settle northerly through the period, around 10 kts or less. && .DMX WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION...Curtis AVIATION...Curtis ####018002885#### FXUS64 KOUN 131130 AFDOUN Area Forecast Discussion National Weather Service Norman OK 630 AM CDT Mon May 13 2024 ...New AVIATION... .SHORT TERM... (Today and tonight) Issued at 240 AM CDT Mon May 13 2024 A short-wave trough will move slowly eastward across the central and southern plains today. The associated surface front will is expected to track closely with it. Fairly high precipitable water values could lead to localized flooding with rain and storms that are expected along part of the front today. Isolated ones could produce near severe hail or wind. Showers and thunderstorms will move slowly eastward today with the aforementioned features. Drier air will filter south behind the front into Tuesday morning. && .LONG TERM... (Tuesday through Sunday) Issued at 240 AM CDT Mon May 13 2024 Weak short-wave ridging will move over Oklahoma until Wednesday when the next upper low approaches from southern California resulting in increased southwesterly flow over Oklahoma. south winds will have brought increased moisture northward. There may be some showers/storms over northern or central Oklahoma Wednesday morning in a warm advection regime. More storms are expected Wednesday afternoon and evening when a lead short-wave likely translates over Oklahoma. Several other weak-short wave troughs are likely through Friday when the larger system finally moves toward the lower Mississippi Valley. Mid-level heights are expected to increase with a ridge over the southern plains during the weekend. This will be associated with afternoon temperatures from the mid 80s to lower 90s Saturday and Sunday. && .AVIATION... (12Z TAFS) Issued at 625 AM CDT Mon May 13 2024 An area of showers and thunderstorms persists across central Oklahoma this morning, with skies ranging from LIFR across southeast Oklahoma to VFR across much of western and northern Oklahoma. This complicated ceiling scenario will persist throughout the day as a cold front pushes through, with intermittent reductions to ceiling/visibilities possible until late afternoon when VFR conditions will prevail everywhere. The cold front's arrival this afternoon will also be a signal for winds to shift to northwesterly and increase to 15 knots. Meister && .PRELIMINARY POINT TEMPS/POPS... Oklahoma City OK 77 56 80 58 / 50 10 0 0 Hobart OK 79 54 83 60 / 40 0 0 10 Wichita Falls TX 81 57 83 61 / 40 0 0 0 Gage OK 76 49 84 57 / 30 0 0 10 Ponca City OK 76 55 79 55 / 60 20 0 10 Durant OK 80 59 82 58 / 50 10 0 0 && .OUN WATCHES/WARNINGS/ADVISORIES... OK...None. TX...None. && $$ SHORT TERM...09 LONG TERM....09 AVIATION...04 ####018005095#### FXUS66 KMTR 131130 AFDMTR Area Forecast Discussion National Weather Service San Francisco CA 430 AM PDT Mon May 13 2024 ...New AVIATION, MARINE... .SYNOPSIS... Issued at 1208 AM PDT Mon May 13 2024 A relatively quiet pattern will persist featuring overnight and morning coastal clouds with clear skies elsewhere. Inland temperatures will warm into the 70s and 80s each afternoon with cool onshore breezes keeping coastal temperatures in the 60s. && .SHORT TERM... (Today and tonight) Issued at 1208 AM PDT Mon May 13 2024 A weak upper low will drift towards the central CA coast while upstream ridging dominates the northeast Pacific. This pattern will promote the subsequent deepening of the marine layer today as low stratus clouds penetrate deeper inland. The top of the marine inversion has continued to increase, and is now up to around 2,000 feet per the Fort Ord profiler. Given this depth wouldn't be surprised to see a little coastal drizzle early this morning in the favorable spots so added this to the forecast. Any accumulations should be quite minor. Otherwise look for low clouds to clear back towards the coast this afternoon with the marine influence keeping coastal/bayside temperatures in the 60s. Elsewhere look for 70s and 80s in the warmest inland valleys, with a few locations in southern Monterey County perhaps nearing 90 degrees. Clouds will push back inland by this evening with mostly cloudy conditions again prevailing for many areas tonight. Lows will dip into the upper 40s && .LONG TERM... (Tuesday through Sunday) Issued at 1208 AM PDT Mon May 13 2024 Temperatures will cool slightly with onshore flow and weak troughing aloft persisting. An upper ridge does build/strengthen over the northeast Pacific by mid week, but it appears our area will remain along its periphery with no strong signal for a warming trend. In general high temperatures will range from the 60s along the coast to the lower-mid 80s for the warmest inland areas. This will only produce a minor HeatRisk for the warmest locations. Lows will generally be in the lower to mid 50s. Coastal clouds are likely during the overnight and AM hours with a gradual clearing towards the coast each afternoon. && .AVIATION... (12Z TAFS) Issued at 430 AM PDT Mon May 13 2024 Currently seeing a mix of VFR-LIFR at the terminals. The marine layer is overall on a deepening trend with the depth currently at about 1,800 feet according to the Fort Ord Profiler; however, it did experience a few hours of compression between the 06Z TAF issuance and this one. LIFR-MVFR conditions are slated to return to all terminals except LVK tonight. Ceiling heights will be highly dependent on the evolution of the marine layer between now and then. Widespread VFR and breezy onshore flow will prevail by this afternoon. Vicinity of SFO...Currently IFR with breezy westerly flow. High-end IFR-low-end MVFR stratus will continue to impact the terminal through the late morning. Winds will remain onshore and breezy through the TAF period. Confidence is low on what exactly the terminal will see overnight in terms of ceiling height due to the lack of model/guidance consensus and a finicky marine layer. The outcome is highly dependent on the evolution of the marine layer between now and then, but current thinking is that the terminal will see a ceiling and it will likely be low-end MVFR-high-end IFR again. SFO Bridge Approach...Similar to SFO. Monterey Bay Terminals...Currently LIFR with westerly flow at both terminals. Conditions will briefly improve to VFR by the afternoon with a quick return to LIFR this evening for MRY and IFR tonight for SNS. Westerly/northwesterly winds will prevail through the TAF period. && .MARINE... (Today through Saturday) Issued at 430 AM PDT Mon May 13 2024 Fair weather will prevail through the week as surface high pressure over the Eastern Pacific Ocean builds and moves east. Fresh northwesterly breezes will prevail Monday and Tuesday before winds begin to diminish mid-week. Significant wave heights will continue to build to 12-15 feet by Tuesday before gradually abating through the rest of the week. && .MTR WATCHES/WARNINGS/ADVISORIES... CA...None. PZ...Small Craft Advisory from 3 PM this afternoon to 9 PM PDT this evening for Mry Bay-Pt Pinos to Pt Piedras Blancas 0-10 nm. Small Craft Advisory until 9 AM PDT Tuesday for Pt Arena to Pt Reyes 10-60 NM. Small Craft Advisory from 9 PM this evening to 9 AM PDT Tuesday for Pigeon Pt to Pt Pinos 10-60 NM. && $$ SHORT TERM...SPM LONG TERM....SPM AVIATION...Sarment MARINE...Sarment Visit us at www.weather.gov/sanfrancisco Follow us on Facebook, Twitter, and YouTube at: www.facebook.com/nwsbayarea www.twitter.com/nwsbayarea www.youtube.com/nwsbayarea ####018006991#### FXUS64 KCRP 131132 AFDCRP Area Forecast Discussion National Weather Service Corpus Christi TX 632 AM CDT Mon May 13 2024 ...New AVIATION... .SHORT TERM... (Today through Tuesday) Issued at 244 AM CDT Mon May 13 2024 Key Messages: ▶ Slight to Enhanced Risk of Severe Thunderstorms for most of South Texas this afternoon Water vapor imagery this morning reveals a shortwave lifting across the southeast US while an upper level low moves across OK/NE. At the surface, a moist onshore flow continues across the region as a warm front remains parked across our northern CWA border. As the upper low lifts across the Plains, a shortwave moving through the southwesterly flow aloft will tug a ribbon of H5 vorticity through the southern part of the state. Meanwhile, instability will be on the rise as diurnal heating kicks in. The main issue today will be just how warm we get. The combination of a thick stratus deck and smoke may keep our temps down a couple of degrees which would decrease our convective potential slightly. However, model soundings depict a highly unstable environment characterized by CAPEs near 5000 J/kg, DCAPE over 1000 J/kg, around 50 knots of bulk shear. It's worth noting that there is a healthy cap in place earlier in the day, but recent trends hint at this cap decaying through the day. If we break through the cap, we could see convection quickly become strong to severe. There are some difference between some of the recent CAM guidance. A few solutions keep most of the activity this afternoon to our north and east. On the other hand, the HRRR and NAM3/12km swing a line through our northern counties. All signs point to supercells developing earlier in day near our northern border where we would see more of a large hail risk. A MCS is likely to take shape this afternoon as a weak boundary approaches from the north. As this MCS moves south-southeast, will see more of a damaging wind risk as well as an increased threat for an isolated tornado or two. All activity will likely be offshore by 03Z or so. Drier air will begin to move into the region overnight in the wake of a weak boundary. There is a low to moderate chance of some patchy fog across the Coastal Plains and Victoria Crossroads as low level moisture lingers. Weak upper level ridging will keep us dry on Tuesday. Taking a quick look at temps, we will see temps across the Brush Country hit triple digits this afternoon. Further east, clouds coverage will keep us in the upper 80s. Majority of the region will be under a moderate risk of heat-related impacts today. Drier air tomorrow will promote warmer temps but a reduced risk of heat related impacts. && .LONG TERM... (Tuesday night through next Sunday) Issued at 244 AM CDT Mon May 13 2024 Key Messages: - Low chance of showers and thunderstorms Wednesday afternoon through the overnight hours. - Low to medium chance of showers and thunderstorms Thursday. - Heat Advisory conditions possible on Thursday and Sunday for the southern inland Coastal Plains and portions of the Brush Country. Quiet weather is in store Tuesday night into Wednesday morning as weak upper-level ridging and quasi zonal flow is in place. Low-level moisture will begin to increase as onshore flow becomes dominant, allowing for PWATs to reach between 1.5 - 2 inches by Wednesday afternoon into Thursday night. By this time, mid-level shortwaves will propagate into the region, acting as a lifting mechanism for this increased moisture. This will result in a low chance (10-20%) for showers and thunderstorms Wednesday afternoon and evening, increasing to a low to medium chance (20-50%) through Thursday. The overall coverage and intensity of the precipitation will depend on the interaction between these disturbances and the available moisture. An upper-level trough is forecasted to move into the region on Thursday, which will support the development of a surface low pressure system over North Texas. This system will drag a cold front into Central Texas, which is expected to pass through South Texas by Friday and into the weekend. This frontal passage may trigger additional convection, although the extent of its reach into South Texas remains uncertain at this time. As for the long-term temperature outlook, things will remain on the warm side, with highs in the 90s along the coast and around 100 across the Rio Grande Plains and Brush Country. The combination of heat and humidity will lead to elevated heat index values Thursday and Sunday, particularly across the southern inland Coastal Plains and portions of the Brush Country, where values could rise to 110- && .AVIATION... (12Z TAFS) Issued at 622 AM CDT Mon May 13 2024 MVFR conditions are in place across all terminals with the exception of LRD. VFR conditions gradually return by mid day. Chances for showers and thunderstorms increase through the morning as a line of storms moves south into the region. Have VCTS starting between 16-18Z for all site (except LRD) with a TEMPO for -TSRA between 19-23Z as the strongest activity should be passing through then. Large to very large hail and damaging winds are possible with these storms. Convection will be offshore shortly after 00Z. MVFR conditions begin to return by 06Z across the Coastal Plains and Victoria Crossroads. && .MARINE... Issued at 244 AM CDT Mon May 13 2024 A generally moderate southeasterly flow will continue through much of the day. A weak frontal boundary will move offshore this evening, shifting the winds out of the northeast through Tuesday morning. A east-southeasterly flow resumes Tuesday afternoon. Increased moisture and an approaching upper disturbance will lead to a 20-40% chance of showers and storms through this evening. An isolated strong to severe storm moving offshore cannot be ruled out. Drier conditions in store on Tuesday. Weak to moderate onshore flow is expected to continue through much of the week. Isolated to scattered showers and thunderstorms will be possible early Wednesday afternoon through Thursday. && .PRELIMINARY POINT TEMPS/POPS... Corpus Christi 94 73 92 73 / 40 20 0 0 Victoria 89 68 93 68 / 60 30 0 0 Laredo 101 74 100 74 / 20 0 0 0 Alice 95 72 95 71 / 40 30 0 0 Rockport 88 74 89 75 / 50 30 0 0 Cotulla 95 72 98 72 / 40 0 0 0 Kingsville 95 73 93 71 / 30 20 10 0 Navy Corpus 90 77 89 77 / 40 20 0 0 && .CRP WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...TC/95 LONG TERM....KRS AVIATION...TC/95 ####018005770#### FXUS63 KGRB 131132 AFDGRB Area Forecast Discussion National Weather Service Green Bay WI 632 AM CDT Mon May 13 2024 Updated aviation portion for 12Z TAF issuance .KEY MESSAGES... - An area of smoke or haze is expected to spread over the region through this afternoon. The smoke or haze may result in poor air quality at times. - Areas of frost are possible over the sandy soil ares of north- central and far northeast Wisconsin tonight and Tuesday night. - After a dry period on Tuesday and Wednesday, the chance of rain and possibly some storms will return at times from Thursday through Sunday. && .DISCUSSION... Issued at 413 AM CDT Mon May 13 2024 Short Term...Today...Tonight...and Tuesday A cold front was moving through the far southern part of the forecast area early this morning. Showers had ended, and skies had cleared across northern WI. Patchy fog was observed across northern WI, and other minor vsby restrictions were likely due to smoke from Canadian wildfires. Temperatures ranged from the upper 30s and lower 40s far north to the middle 50s to lower 60s south. Smoke trends and frost potential will be the primary concerns with the short-term forecast. The close proximity of the cold front, weak short-wave energy and the RRQ of a weak jet streak may bring scattered showers back into the far southern part of the forecast area this afternoon, but skies will remain partly cloudy farther north. Deep mixing should allow dew points to mix out, with relative humidity dropping to 25 to 30 percent in the sandy soil areas. High temperatures should warm to the middle 60s to middle 70s, except near Lake Michigan, where E-NE winds will keep highs in the middle 50s to lower 60s. Canadian high pressure centered over Ontario will bring mostly clear skies, decreasing winds and a dry air mass to the region tonight. This may lead to patchy/areas of frost across far northern WI. This is not a slam dunk, as there is enough of a pressure gradient to support a steady light E-NE wind through the night. Will let the day shift take a closer look at this, and decide on potential frost/freeze headlines. Lows should be in the 30s north, and lower to middle 40s south. On Tuesday, the Canadian high will settle across the Lake Superior region, with northeast winds pushing cooler and drier air into the forecast area. Low relative humidity in the 20 to 30 percent range will be found in the sand areas. Highs will be in the 60s, but gusty NE winds will keep bayshore and lakeshore areas in the middle 50s to lower 60s. Smoke Trends: HRRR/RAP Smoke models show similar trends, with smoke at the surface and aloft impacting the area today. An Air Quality Advisory (issued by the Wisconsin DNR) remains in effect through 10 am, but may be extended through the day. Minor vsby restrictions (mainly 3-6SM) will be possible at times. Surface- based smoke is expected to gradually clear from the north and east late this afternoon and evening, but smoke aloft will likely linger through tonight and part of Tuesday. Long Term...Tuesday Night Through Sunday Generally quiet spring weather is expected through midweek, then becoming the weather will become unsettled from Thursday through the upcoming weekend. Beyond Thursday, forecast confidence in the details drops significantly due to large spread amongst and within various ensemble systems. Rain and thunderstorm chances: Weak high pressure will ensure dry weather sticks around for Tuesday night through Wednesday. This changes on Wednesday night when a broad shortwave trough and associated cold front track across the northern Mississippi Valley and western Great Lakes regions. Chances of light rain have increased on Wednesday night and Thursday, but with little to no instability, will continue to leave out a chance of thunderstorms. Details get murky thereafter, but conceptual models and the NBM indicate that precip chances reach their minimum after the front departs late on Thursday night into Friday. Another period where chances of precip seem to increase is on Sunday when ensembles indicate height falls taking place with shortwave energy moving into the northern Great Lakes. Some instability may surge into the area by this time, so will have a chance of thunderstorms. Temperatures: Weak high pressure, clear skies, and light winds will be favorable for frost development on Tuesday night. Highest probabilities will be across the sandy soil areas of far northern WI. Otherwise, 850mb temps will be rebounding after reaching their minimums on Tuesday and Wednesday. Clouds and precip may impact temps somewhat, but in general, there will be a warming trend starting Wednesday into the weekend. Temps could be approaching 80 degrees again at some locations by Saturday and Sunday. && .AVIATION...for 12Z TAF Issuance Issued at 627 AM CDT Mon May 13 2024 A few showers may work their way north into the southern part of the forecast area this afternoon, and might just clip the MTW TAF site. Otherwise, the main concern is smoke/haze associated with Canadian wildfires. The smoke will occasionally drop vsbys to 3-6SM today into early tonight, with a gradual improving trend from north to south in the late afternoon and evening. Otherwise, expect mainly VFR flight conditions across the region, with light to moderate NE winds. && .GRB WATCHES/WARNINGS/ADVISORIES... None. && $$ DISCUSSION.....Kieckbusch/MPC AVIATION.......Kieckbusch ####018004064#### FXUS63 KFSD 131134 AFDFSD Area Forecast Discussion National Weather Service Sioux Falls SD 634 AM CDT Mon May 13 2024 .KEY MESSAGES... - Outside of a few showers along and south of Highway 18 this morning, should see largely dry conditions prevail through Tuesday. Wildfire smoke from Canada will continue to overspread the region during this time. - Moderate chances (30% to 60%) for scattered showers and thunderstorms return Tuesday night through Wednesday. Severe weather is not expected. - Confidence in rain chances remain low for the end of the week given the model variability in place. Do have higher confidence, however, that at or above normal temperatures will continue. && .DISCUSSION... Issued at 303 AM CDT Mon May 13 2024 TODAY THROUGH TUESDAY: Aside from a few showers along and south of Highway 18, latest radar imagery reveals quiet conditions across the region. Winds during this time have remained fairly light, with temperatures hovering in the 40s to lower 50s. Expect these showers to linger for much of the morning hours as a stacked low just south of area slowly meanders eastward across the central Plains. Outside of these showers, should see largely dry conditions prevail through Tuesday with highs in the lower 70s. That being said, do think it's worth noting that Canadian wildfire smoke will continue to overspread the region, which may result in periods of reduced visibilities. TUESDAY NIGHT THROUGH THURSDAY: Upper level trough and sfc warm front surge toward the region Tuesday evening, causing showers and storms to return to the forecast. At this time, most guidance generally agrees that isolated to scattered coverage will be likely along and west of the James River near midnight as the warm sector builds overhead. In regards to severe weather, latest soundings still reveal limited instability and shear, suggesting that the overall threat should remain low. Rather, think the primary hazards with any storm will be lightning, brief heavy downpours, and gusts up to 50 MPH. As alluded to in the previous discussion, could see a lull in activity across our area Wednesday morning, with showers and storms possible again during the afternoon/evening ahead of an advancing cold front. Again, severe chances look to remain low given the lack of significant instability in place. While a few lingering showers may still be possible Thursday morning, expect the overall trend to be toward drier conditions. In terms of rainfall, have accumulations ranging between a tenth to a quarter of an inch, though locally higher amounts may still be possible. FRIDAY THROUGH SUNDAY: Model variability concerning how the upper level pattern will evolve increases heading into the weekend, making it hard to put too much confidence behind any one particular solution just yet. While most resemble a quasi-zonal structure, there is still quite a bit of variance regarding the timing of individual shortwaves. So for now, will continue to advertise periodic chances for showers and storms through the weekend. For what it's worth, ensembles continue to support low chances (generally 20-30%) of receiving a tenth of an inch of precipitation in any one 24 hour period. Otherwise, look for near to above normal temperatures to continue. && .AVIATION /12Z TAFS THROUGH 12Z TUESDAY/... Issued at 634 AM CDT Mon May 13 2024 Expect largely quiet conditions to prevail across the region today, as Canadian wildfire smoke lingers overhead. Could see impacts near the sfc, mainly in the form of reduced vsbys to MVFR levels. Otherwise, look for winds to remain out of the northeast, with occasional gust up to 20 MPH possible through the afternoon. && .FSD WATCHES/WARNINGS/ADVISORIES... SD...None. MN...None. IA...None. NE...None. && $$ DISCUSSION...SST AVIATION...SST ####018007078#### FXUS64 KAMA 131135 AFDAMA Area Forecast Discussion National Weather Service Amarillo TX 635 AM CDT Mon May 13 2024 ...New AVIATION... .SHORT TERM ... (Today through Tuesday night) Issued at 324 AM CDT Mon May 13 2024 After several storms to round out the weekend, the main low pressure that caused it will slowly be moving northeast through Kansas today. On the backside of the departing mid level low pressure system, we could see some additional showers or a storm or two for the northeastern combined Panhandles, in closer proximity to the departing low. Otherwise, a nice day in store across the Panhandles. A bit breezy up north in closer proximity to aforementioned departing low pressure system with steep sfc gradient. But temperatures will be near average for mid May with high temperatures ranging from the mid 70s to lower 80s. A H500 ridge will move towards the southern Plains tomorrow. This should keep most of the area dry once again. A secondary disturbance poleward of the main ridge axis will develop some showers and storms as it works across the central Rockies. This could bring rain chances back to the northern combined Panhandles tomorrow evening into tomorrow night as the main ridge axis moves east. Chances are not too high (20-30%), but there is at least a chance to bring more rain chances to the northern Panhandles where rainfall is definitely needed. High temperatures tomorrow will add another 10-15 degrees compared to today as southerly winds return. Highs will range from the mid 80s to lower 90s. Meccariello && .LONG TERM ... (Wednesday through Sunday) Issued at 324 AM CDT Mon May 13 2024 Wednesday morning, an upper-level ridge will be just east of the Panhandles with an upper-level trough over southern California/northern Baja California, and a shortwave trough embedded in the flow is currently expected to be somewhere in New Mexico. Throughout the day the shortwave trough is favored to move toward the Panhandles with dew points generally in the 40s and 50s in place, though there are hints that an area of westerly or southwesterly winds will move in to the southwestern TX Panhandle allowing for some lower dew points to work in. Nonetheless, it appears as though forcing in the form of PVA and a cold front moving in from the north will arrive in the afternoon hours and allow for the development of thunderstorms. Adding to the confidence for the sustainability of thunderstorms is that all models suggest that there will be rather impressive mid-level theta-e advection in the afternoon. There is some question regarding how potential moisture return will be, but given how models have handled it in the past few weeks and the recent widespread rainfall, will opt to lean toward the more potent moisture solutions (e.g., NAM). Steep to very steep lapse rates will be in place from the surface through 6 km on the order of an average of around 8.5 C/km to 9 C/km, thus it won't take much low-level moisture to get enough instability for the threat for a strong to severe thunderstorm. The guidance that has greater low- level moisture gives portions of the northern and eastern Panhandles around 1000-1500 J/kg of MLCAPE. The strength of the low-level winds won't be anything to write home about, but deep layer shear looks favorable for storm organization, thus supercellular structures will be possible. A long, straight hodograph is favored which suggests a splitting supercell will also be possible. The primary threats are large hail (via steep lapse rates) and damaging winds (via steep low- level lapse rates, inverted-V signature). Showers may continue through Wednesday night as a cold front with low-level moisture behind it moves through the Panhandles and additional lobes of vorticity stream across the area. Will have to watch Thursday as showers and thunderstorms may once again occur. GFS progresses the upper-level trough quicker than the ECMWF, and a surface low develops in western Texas. ECMWF is slower with the trough progression and develops a surface low in southwestern Texas. Additionally, GFS doesn't push the cold front as far south as the ECMWF. As noted above, low-level moisture is wrapped in behind the cold front, thus for a more widespread threat for showers and thunderstorms on Thursday, will need a solution like the GFS to verify such that sufficient low-level moisture will be in place across the Panhandles. A solution like GFS would also suggest a few strong to severe thunderstorms would be possible for much of the Panhandles. If a solution like the ECMWF verifies where the cold front and moisture is further south, then perhaps only the southern TX Panhandle could see a chance for showers and thunderstorms. Owing to the timing differences between the models regarding the progression of the trough, there's quite a bit of uncertainty for Friday. GFS could have lingering rain in the south, while ECMWF would be dry. An upper-level ridge builds over the Plains this weekend as an upper- level trough moves in to the Western US. Sunday looks to be the hottest day of the year thus far with widespread upper-80s to mid-90 degree highs. Will have to watch the early to middle portion of next week for a potential weather system as the aforementioned upper- level trough moves east. This could mean severe weather or dry and breezy weather... or both. We'll have to wait and see. Vanden Bosch && .AVIATION... (12Z TAFS) Issued at 632 AM CDT Mon May 13 2024 VFR conditions expected throughout the 12Z TAF period. Winds will be out of the north, veering to southerly towards the end of the TAF period with winds at 5-15 kts, with higher gusts at times. Skies will be mostly clear. Meccariello && .PRELIMINARY POINT TEMPS/POPS... Amarillo TX 78 49 86 55 / 0 0 0 10 Beaver OK 75 47 85 54 / 20 0 0 20 Boise City OK 74 45 85 50 / 10 0 10 20 Borger TX 81 51 91 57 / 10 0 0 10 Boys Ranch TX 81 49 91 53 / 10 0 0 10 Canyon TX 78 49 87 54 / 0 0 0 10 Clarendon TX 78 51 84 55 / 0 0 0 10 Dalhart TX 77 45 86 48 / 10 0 10 20 Guymon OK 76 47 87 52 / 10 0 0 20 Hereford TX 79 49 89 54 / 0 0 0 10 Lipscomb TX 75 49 85 56 / 20 0 0 20 Pampa TX 76 50 86 56 / 10 0 0 10 Shamrock TX 78 51 84 56 / 10 0 0 10 Wellington TX 79 51 84 56 / 0 0 0 10 && .AMA WATCHES/WARNINGS/ADVISORIES... TX...None. OK...None. && $$ SHORT TERM...29 LONG TERM....52 AVIATION...29