####018007751#### FXUS64 KLCH 181756 AFDLCH Area Forecast Discussion National Weather Service Lake Charles LA 1256 PM CDT Thu Apr 18 2024 ...New AVIATION... .UPDATE... Issued at 923 AM CDT Thu Apr 18 2024 Short wave moving across in the fast west-southwest flow aloft over-performing some and allowing elevated showers to get going. Therefore, have updated the forecast to increase pops for this morning into early afternoon. Activity should decrease and move off to the west during the afternoon hours. Despite the cap seen on the 18/12z upper air sounding, enough elevated CAPE and favorable mid level lapse rates to get some thunder and lightning with the showers so will also add thunder to the weather grid with the increase in pops. Otherwise, remainder of the forecast is on track. Rua && .SHORT TERM... (Today through Saturday night) Issued at 330 AM CDT Thu Apr 18 2024 A broad regime of surface high pressure extends west across Florida into the central Gulf of Mexico. Southerly flow accompanies this pattern locally facilitating warm, humid, and primarily cloudy conditions. Low pressure troughing over Texas has created a weak gradient across SETX / SWLA, to generate SSE breezes with gusts near 20 mph again. A well defined 700-800mb ridge aloft caps off any potential convection with very noticeable inversion / dewpoint depression during recent upper air soundings. Mid to upper level air moisture profiles are fairly humid which has resulted in some light elevated precip / virga over the northern tier portions of the CWA trending across NETX into north central LA. POPs have been minimized given this dry layer aloft and low level subsidence through the start of the weekend. Temperatures under this southerly regime in the meanwhile will continue to climb toward the mid 80’s for many locations. The focus continues to be throughout the weekend which trends into the early long rage. In the meanwhile, Saturday, a cold front will begin to slow and modify as downstream low pressure detaches from this pattern over the Southern Plains. While the strongest divergence remains over the Northeast where the longwave trough pattern slowly migrates into the NW Atlantic, a relatively small shortwave deepens across NWTX which creates better dynamics in the low levels. The result is a weak surface trough along the advancing frontal pattern. POPs increase along with chances of thunder throughout the late afternoon and overnight into Sunday where the front, driven by a building ridge over the central Plains, moves offshore. At this time, no modes of severe weather are elevated. The national blend of models has been more consistent in keeping event totals closer toward 0.50” - 0.75.” Worth noting the potential for excessive rainfall is possible, but not highly favored ahead of the frontal boundary Saturday evening through Sunday. Northern portions of the CWA there stands a marginal risk for excessive rainfall. Together with probabilistic guidance, northern tier counties and parishes stand the better chances – albeit still bordering marginal— for any excessive rainfall. Reduced diurnal highs and brief northerly flow will take place as the front clears into the Gulf Sunday. Kowalski/30 && .LONG TERM... (Sunday through Thursday) Issued at 330 AM CDT Thu Apr 18 2024 As Sunday gets underway, the cold front will be situated near the coast or just offshore. A cooler airmass will settling into the area as high pressure builds south across the plains. Meanwhile, widespread showers and a few storms are expected to be ongoing during the morning as a midlevel southern stream shortwave crosses the region. Instability and shear are expected to be rather meager so no severe weather is expected, and any thunder will likely be limited. Moisture, however, will be prolific with PWATs peaking near 1.8 inches (near the max value for mid April per SPC climatology). This will be sufficient for some heavier showers and high rainfall rates, which could pose a localized flash flood risk in urban and low lying areas, primarily over our eastern zones where the highest rain chances are expected to be through early afternoon. Overall, rainfall totals are generally expected to be between one half to one inch, but locally higher amounts will be possible where heavier showers occur. Convection should diminish from west to east during the afternoon as dry northwesterly flow develops in the wake of the shortwave. Lingering cloud cover combined with cold air advection on gusty northerly winds will make for rather cool conditions on Sunday, and daytime highs will likely struggle to reach 70 degrees north of the Highway 190 corridor. As surface high pressure settles across AR Sunday night, winds will diminish across the region. Temperatures Sunday night into Monday morning are expected to be the chilliest of the forecast period, with lows falling to around 50 degrees across the northern zones (upper 40s will be possible across central LA), with lower 50s across the southern half of the area. Cloud cover will decrease during the day Monday, with rather pleasant and seasonable conditions expected. A warming trend will develop going into the midweek period as the surface high slides east and low pressure forms over the southern plains. Flow aloft will trend more zonal, with intermittent weak disturbances expected to bring some low rain chances back into the area by Tuesday. Some differences begin to arise in the global models beyond this time, but there is a general consensus toward improving rain chances for Wednesday and Thursday (Days 7-8). NBM PoPs remain on the drier end of the spectrum but will likely be evolving over the coming days. 24 && .AVIATION... (18Z TAFS) Issued at 1253 PM CDT Thu Apr 18 2024 A short wave will continue to move across the forecast area for the next few hours with MVFR ceilings and a few showers/storms through about 18/22z. Skies are expected to briefly clear of all low clouds once the short wave moves off to the east with VFR conditions into the early evening hours. Once again tonight, with light southerly flow bringing in low level moisture, low clouds will form under the cap with MVFR ceilings becoming IFR overnight. Some visibility restrictions will be possible from patchy fog with visibility in the 2 to 5 mile range, but low ceilings are still expected to be the main problem. Rua && .MARINE... Issued at 324 PM CDT Wed Apr 17 2024 A similar pattern through the end of the week with a surface high off the Florida Atlantic coast ridging into the coastal waters with lower pressure across the Southern Plains. This will result in light to occasionally modest southerly winds into the beginning of the weekend. A surface front will enter the region over the weekend with an increase in shower activity. This front will move across the coastal waters late Saturday night into Sunday morning with winds becoming offshore that will persist into early next week. Rua && .PRELIMINARY POINT TEMPS/POPS... AEX 85 67 85 65 / 20 0 10 10 LCH 82 70 85 69 / 30 0 0 0 LFT 85 71 86 69 / 20 0 0 0 BPT 84 71 85 69 / 40 0 0 0 && .LCH WATCHES/WARNINGS/ADVISORIES... LA...None. TX...None. GM...None. && $$ SHORT TERM...30 LONG TERM....24 AVIATION...07 ####018004810#### FXUS61 KILN 181756 AFDILN AREA FORECAST DISCUSSION National Weather Service Wilmington OH 156 PM EDT Thu Apr 18 2024 .SYNOPSIS... Weak high pressure will move east across the middle Ohio Valley today, resulting in dry weather. For tonight, low pressure will ride northeast along an eastward advancing cold front, bringing renewed chances for showers and thunderstorms. Precipitation will taper off on Friday as the front continues east. High pressure will then build back into the region for the weekend, bringing below normal temperatures along with chances for frost. && .NEAR TERM /THROUGH FRIDAY/... Not too many changes to the previous forecast. Tweaked temperatures and dew points slightly as it took us a bit longer to warm, but otherwise, everything on track. Should get pretty dry this afternoon and RHs south of I-70 fall into the low 30s/upper 20%s. However, not too concerned about any type of fire weather, given recent rains and lack of wind today. Previous discussion->Through sunrise, CAA stratocumulus clouds will skim our northern zones, while the rest of the region remains mostly clear. For today, dry weather is on tap as a weak ridge of high pressure traverses across the middle Ohio Valley. Some high clouds may spill into the region from the west, especially late due to upstream convection. It will be warm with highs ranging from the lower 70s north to the lower 80s south. && .SHORT TERM /FRIDAY NIGHT THROUGH 6 PM FRIDAY/... For tonight, a lead mid level s/wv will eject east from the middle Mississippi Valley into the middle Ohio Valley. Associated low pressure and a cold front to our west will move east into the forecast area overnight. After analyzing various CAMs, it appears that we will see the weakening north end of an MCS complex. This weakening pcpn is expected to arrive into our forecast area later in the evening and during the overnight period when overall instability will be decreasing (falling below moderate instability) Thus, it appears that the threat for any strong or severe storm will be limited to mainly the evening hours and across parts of our western CWFA. Isolated strong or damaging wind gusts would be the main threat. Showers and a few embedded thunderstorms will then continue overnight as the system shifts farther into the CWFA. Lows will range from the upper 40s northwest to the lower 60s southeast. On Friday, the cold front will exit east out of the forecast area by the afternoon hours. Pcpn will taper off and should then end by the afternoon hours as well. Mostly cloudy skies will gradually become partly cloudy in the afternoon. Under a northwest flow, cooler temperatures are forecast. Highs will range from the upper 50s northwest to near 70 southeast. && .LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/... High pressure builds in from the northwest Friday night through Sunday night. Below average temperatures persist along with northwesterly/northerly flow. Forecast lows on Saturday night and Sunday night are expected to drop into the mid to lower 30s north of the Ohio River which could support frost. However, there still remains uncertainty in regards to frost potential this weekend since some cloud cover may remain in place overnight. High pressure finally moves overhead on Monday and Monday night continuing the trend of dry conditions and cool weather. The next chance for rain arrives on Tuesday and into the midweek when another upper level wave and surface cyclone may move across the region. Temperatures may moderate ahead of the disturbance before dropping back closer to seasonal averages behind the system. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... VFR conditions at all sites to start the period with high clouds beginning to encroach from the west. Clouds thicken and lower as the afternoon/evening continues ahead of the next low pressure system that will arrive during the overnight. Rain moves in around midnight; highest probability of thunder remains along the Ohio River, so have only included at the KCVG and KLUK TAF sites. CIGs lower to MVFR during the overnight into early morning hours with periods of reduced VSBYs. Conditions improve late morning on Friday. Winds pick up on the back end of the system, gusting to around 25 knots Friday morning into afternoon hours. OUTLOOK...MVFR ceilings/visibilities possible on Friday. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...None. KY...None. IN...None. && $$ SYNOPSIS...Hickman NEAR TERM...CA/Hickman SHORT TERM...Hickman LONG TERM...Campbell AVIATION...CA ####018006606#### FXUS64 KBMX 181758 AFDBMX Area Forecast Discussion National Weather Service Birmingham AL 1258 PM CDT Thu Apr 18 2024 ...New SHORT TERM, AVIATION... .SHORT TERM... (This afternoon through Friday) Issued at 1247 PM CDT THU APR 18 2024 A broad area of low-level ridging is centered over the Central and Eastern Gulf of Mexico while lower amplitude mid-level ridging is also present over the Eastern CONUS, producing westerly flow aloft. Warm conditions are expected this afternoon with a mix of sun and clouds. Highs will reach the mid 80s. There will be an opportunity for some storms late today and into the evening hours as an embedded shortwave moves from the Midsouth region and across the Tennessee Valley. Some thunderstorms associated with this feature are already ongoing near the Mississippi River, but that activity has really struggled to maintain intensity with eastward extent as we still have residual dry air in the mid-levels. Some deeper moisture is confined near the shortwave, so expect the thunderstorms to eventually move into western portions of the area early this evening as the shortwave moves east, but instability will be on the decline by that point. Any strong storms moving through Mississippi should be on a weakening trend as they reach Central Alabama, so expect the activity to be sub-severe. Meanwhile, a surface low is forecast to moves towards the Ohio Valley tonight dragging a cold front across the Lower MS River Valley. Convection along the southern sections of the front will really struggle as it moves further into an unfavorable environment dominated by the Gulf ridge and lacking in deep moisture. As such, expect another round of decaying showers and a few storms to affect primarily the far northern portions of the area after midnight before diminishing by sunrise. Patchy fog appears likely tomorrow morning, especially in the south. Will monitor trends to see if a Dense Fog Advisory is needed. The frontal boundary will be near the I-20 corridor by tomorrow afternoon. As temperatures warm into the lower to mid 80s, some isolated to scattered thunderstorms will develop. Despite MUCAPE ranging from 2000-3000 J/kg along the surface boundary, thunderstorm growth is expected to struggle through the dry air, limiting coverage, intensity, and longevity, but gusty thunderstorm winds will be possible in a few instances. 86/Martin && .LONG TERM... (Friday night through next Wednesday) Issued at 208 AM CDT THU APR 18 2024 The boundary will continue to shift southward through the night Friday, stalling somewhere between I20 and I85 in the southern half of the area. Low level flow south of the boundary will be out of the south and southwest, while flow north of the boundary will be from the northwest. This boundary will allow for an axis of convergence for storms to develop Saturday afternoon, and through much of the day on Sunday. Saturday afternoon, the greatest shear will be in areas along and north of I20, with the greatest instability along and south of the boundary, along with PW values just shy of the 90th percentile for this time of year. Scattered showers and thunderstorms are possible Saturday afternoon through the early night. Wind profiles are fairly weak through the midlevels, so a few strong storms are expected. Any activity should weaken through the evening Saturday, with scattered showers and thunderstorms expected Sunday, increasing in coverage and intensity through the morning. The entire area could see rain, but the higher chances will be around this same boundary. Shear will be much higher Sunday afternoon, though instabilities are expected to be less than Saturday. High temperatures will be near normal in areas north of the boundary, while areas south of the boundary see temperatures a couple of degrees above normal. With cloud cover anticipated the entire weekend, areas north of the boundary could be up to 10 degrees or more below normal on Sunday, with areas south of the boundary a few degrees below normal. By Sunday evening, a high pressure developing over the western MS River Valley will move east, and the weakening front will move east ahead of that high. Winds will be predominately from the west Monday through Wednesday bringing moisture to the mid and upper levels and warm air to the state. The area should remain dry with the next chance for rain in the general timeframe of Thursday when a low pressure system is expected to move across Alabama. Temperatures are expected to rebound quickly, reaching near normal temperatures by Tuesday, and above normal temperatures in the low to mid 80s by Wednesday. 24 && .AVIATION... (18Z TAFS) Issued at 1247 PM CDT THU APR 18 2024 A brief period of VFR conditions is expected for the first half of this TAF period, but some convection is forecast to move into the area this evening associated with a mid-level shortwave. Coverage is expected to decrease with time. With most of the activity ending by 06Z, IFR ceilings are then expected to develop with some patchy fog possible, mainly at MGM/TOI. Ceilings will be very slow to rise tomorrow morning. 86/Martin && .FIRE WEATHER... Isolated to scattered showers/storms are possible in the northern half of the area this afternoon, with the best chances north of the I-20 corridor. Increasing rain chances late tonight for areas north of I-20. Min RH values 40-55% this afternoon and Friday afternoon, with 20 foot winds should be light and variable this morning becoming south 5-7 mph by the afternoon. winds will be shifting to a more westerly direction on Friday but remain less than 7 mph. Max RH values tonight will be again right around 100%. Rain chances remain in the forecast through Sunday. && .PRELIMINARY POINT TEMPS/POPS... Gadsden 63 81 57 76 / 50 50 10 30 Anniston 64 82 60 77 / 50 40 10 30 Birmingham 66 81 61 76 / 50 40 10 40 Tuscaloosa 65 82 61 75 / 60 40 10 40 Calera 66 81 61 76 / 50 40 10 40 Auburn 66 82 65 81 / 20 20 10 40 Montgomery 65 85 64 83 / 20 20 10 40 Troy 64 85 64 86 / 10 20 0 40 && .BMX WATCHES/WARNINGS/ADVISORIES... None. && $$ SHORT TERM...86/Martin LONG TERM....24 AVIATION...86/Martin