####018005397#### FXUS62 KJAX 200503 AFDJAX Area Forecast Discussion National Weather Service Jacksonville FL 103 AM EDT Tue May 20 2025 ...New AVIATION... .UPDATE... Issued at 837 PM EDT Mon May 19 2025 For the latest NE FL and SE GA Daily Key Messages please visit: https://www.weather.gov/media/jax/briefings/nws-jax-briefing.pdf Pretty quiet and seasonably mild this evening with high pressure in control and generally below normal layer moisture. Some scattered high clouds continue to move across the area and will continue to do so throughout the night. In addition, patchy to areas of fog and low clouds will be possible towards the Suwannee River Valley once again late tonight and early Tuesday Morning with some very low level moisture from the light southwest breeze. Low temps in the upper 60s to low 70s will be common inland, near the mid 70s at the immediate coast. && .SHORT TERM... (Tuesday through Wednesday night) Issued at 117 PM EDT Mon May 19 2025 The ongoing heat wave will continue through Wednesday, initially under the influence of an upper ridge before it's flattened by a quick-moving shortwave ejecting across the NE CONUS. A cold front will be swept into the area late Wednesday with scattered showers and storms developing out ahead of it. Despite the lack of dynamics, moist southwesterly flow will build instability Wednesday afternoon, leading to scattered thunderstorms, some of those storms could become strong. Afternoon temps continue in the 90s and, with increasing moisture, heat index values will push up to nearly 105F by Wednesday afternoon. Offshore flow will push heat all the way the beaches each day. Increasing cloud cover Wednesday afternoon may provide a smidge of relief from the heat. && .LONG TERM... (Thursday through Sunday) Issued at 117 PM EDT Mon May 19 2025 As the first frontal passage slides toward south Florida, a second front will be pushed south across the southeastern US Thursday and through the local area Thursday night. This will be a dry frontal passage and help lower temperatures closer, though still above, to climo. Canadian high pressure will build in from the north through Saturday and then extend to the northeast by Sunday. Deeper return moisture will build back across the area during the early part of next week and increasing the potential for diurnal sea breeze convection. && .AVIATION... (06Z TAFS) Issued at 1259 AM EDT Tue May 20 2025 Patchy fog is possible this morning, which may cause restrictions. The greatest chance for restrictions in fog this morning will be at KGNV. Otherwise, prevailing VFR conditions at most area TAF sites this period. && .MARINE... Issued at 117 PM EDT Mon May 19 2025 Atlantic high pressure will weaken early this week, but will still extend its axis westward across the Florida peninsula. Onshore winds for nearshore waters associated with the diurnal sea breeze will briefly surge from out of the south this evening before shifting to southwesterly and weakening overnight. A cold front will enter the southeastern states on Tuesday night and Wednesday, crossing our local waters on Wednesday evening. Scattered showers and thunderstorms will accompany this frontal passage, with prevailing winds shifting to northwesterly by Thursday morning as this front pushes southward through the Florida peninsula. High pressure will then build into the southeastern states late this week through the early portions of the Memorial Day weekend. A warm front may lift northeastward across our local waters by late in the upcoming weekend. Rip Currents: Low surf heights will keep a low risk in place at all area beaches through at least Thursday. && .FIRE WEATHER... Issued at 117 PM EDT Mon May 19 2025 Areawide hot temperatures and high dispersion with the exception of the immediate coast through Tuesday. Strengthening southwesterly flow ahead of an incoming front will lead to high dispersion again Wednesday even at the coast. Scattered showers and storms will accompany the front as it passes through Wednesday afternoon and evening. Hot and dry conditions will set up behind the front late this week and into the weekend followed by a return of easterly onshore winds, progressive Atlantic afternoon sea breezes, and increasing daily thunderstorms. && .CLIMATE... Issued at 348 AM EDT Mon May 19 2025 Daily Record High Temperatures through Wednesday at our designated climate sites: Mon 5/19 Tues 5/20 Wed 5/21 --------------------------------- Jacksonville 97/1960 99/1962 99/1938 Gainesville 99/1899 97/1938 100/1938 Alma, GA 97/1960 99/1962 97/1962 Craig Airport 92/2006 97/2006 98/2006 && .PRELIMINARY POINT TEMPS/POPS... AMG 92 70 90 64 / 0 0 40 0 SSI 91 73 91 70 / 0 0 30 10 JAX 96 70 96 68 / 0 0 30 10 SGJ 93 70 95 72 / 10 0 20 10 GNV 94 70 93 69 / 0 0 20 10 OCF 93 70 92 72 / 0 0 10 10 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...None. GA...None. AM...None. && $$ ####018009884#### FXUS63 KLMK 200503 AFDLMK Area Forecast Discussion National Weather Service Louisville KY Issued by National Weather Service Indianapolis IN 102 AM EDT Tue May 20 2025 .KEY MESSAGES... * Scattered showers and thunderstorms late today into tonight. Some storms could be strong over southern Kentucky with gusty winds and marginally severe hail. * Strong to severe thunderstorms are possible Tuesday into Tuesday evening. Damaging winds, large hail, and tornadoes are possible, along with heavy rainfall and flooding. * Well below normal temperatures are expected Thursday into the Memorial Day weekend. && .FORECAST UPDATE... A warm front is draped southeast through southern IL, far western KY, and Middle TN this evening. A couple small clusters of convection have developed near the boundary in Middle TN, drifting north across the KY border while weakening. Forcing is not all that strong this evening, with effective deep-layer shear of 30-35 kts. MLCAPE exceeding 1000-1500 J/kg in south- central KY may allow a storm to briefly become strong. The primary threats remain locally gusty winds and small to marginally severe hail. However, convection will remain fairly isolated and confined to south-central KY through the remainder of the evening hours. Upstream, severe convection has developed across portions of TX, OK, KS, and MO this evening in the warm sector. This activity is expected to push east across the Mid-MS Valley tonight. Showers/weakening convection still expected to ride ENE across southern IN and central KY Tuesday morning, mainly after 4 AM. The severe weather threat continues to look relatively low/marginal during the morning hours, with perhaps some gusty winds and hail in the strongest updrafts. One additional update was to expand the Flood Watch for tomorrow as confidence is increasing that the extent of heavier rain will now stretch closer to the Ohio River. Additional adjustments may be made later tonight as new model data arrives. .SHORT TERM /THROUGH WEDNESDAY/... Issued at 353 PM EDT Mon May 19 2025 Afternoon satellite imagery shows clearing skies in the wake of a weak MCV moving through central Tennessee. With the return of sunshine across the region, temperatures have warmed into the middle to upper 70s over southern Indiana and northern Kentucky. Across southern Kentucky, temperatures were in the upper 70s. Through the remainder of the afternoon, no significant weather is expected. Afternoon highs should top out in the 75-80 degree range across southern Indiana and northern Kentucky. Across southern Kentucky, south of the Cumberland Parkway, highs will top out in the upper 70s to the very low 80s. For tonight, cloud will increase by mid-late evening as high cloud cover spreads eastward from ongoing/expected convection over Missouri. A warm frontal boundary is forecast to lift northeastward overnight. Combination of the warm front along with increasing isentropic ascent will lead to a period of elevated convection moving into the region late tonight (mainly between 3-7 AM EDT). Model proximity soundings show about 20-25 kts of shear along with some elevated instability. Unlike last week, we do not have the impressive elevated mixed layer with this system. Overall, the threat of severe weather with this activity looks to be marginal with heavy rainfall, lightning, and perhaps some marginally severe hail would be the main threats with this initial activity. Moving into Tuesday, surface warm frontal boundary will continue to lift northeast during the morning. Some additional showers and thunderstorms will be possible during morning hours, mainly just after sunrise, as convective outflows move across the region. The extensiveness of these storms and associated cloud cover do result in uncertainty about how much the atmosphere will recover during the afternoon. However, there is more confidence that airmass recovery will be much more possible across southwest and southern KY as a mid-level dry slot pivots into the region behind the advancing warm front and ahead of an approaching cold front. The expected partial clearing across southwestern and southern KY should lead to a fairly rapid warmup with the atmosphere destabilizing in quick order. Forcing will arrive in the region via an approaching mid-level jet streak which we’ll be in the left exit region as it approaches. Model profiles show an increasing low-level jet pushing into the region by early afternoon resulting in a favorable wind profile for supercells. Overall, a mix of supercells and multi- cellular convection looks likely across portions of southwestern KY and southern KY initially. These storms will pose a threat for all hazards including damaging winds, hail, and isolated/scattered tornadoes. As the afternoon progresses, upscale growth into one or more lines looks increasingly likely with damaging winds and QLCS tornadoes being possible. The highest threat of severe looks to remain in areas south of the WK/BG Parkways where there is a better chance of clearing in the late morning. Further north from the Parkways up to near and north of the Ohio River, there is considerable uncertainty on whether cloud cover will hold strong and keep instability lower. Additionally, there is uncertainty in how multiple waves of thunderstorms may alter the overall sub-mesoscale environment across the region. Overall, we like the current placement of the slight and enhanced risks. If the morning convection moves out quicker and more sufficient clearing develops, the enhanced risk could be expanded more to the north in subsequent outlooks. The threat of multiple waves of thunderstorms combined with higher than normal precipitable water values suggests an elevated flooding threat. The highest QPF swath looks to set up along and south of the WK/BG Parkways. After coordination with WFO JKL, we’ll be hoisting a Flood watch from Tuesday afternoon through early Wednesday morning. Surface cold front is forecast to push through the region Tuesday evening and will end the threat of severe weather from west to east by mid-late evening. Cooler and drier air will filter into the region with lows in the low-mid 60s. For Wednesday, deep cyclonic flow will be in place across the region. With colder air aloft working into the region, lapse rates will steepen in the afternoon and some scattered rain showers will be possible across the northeastern half of the forecast area. These showers will diminish toward sunset with a dry evening expected. Highs Wednesday will top out in the upper 60s to around 70. Overnight lows will be in the lower-middle 50s. .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... Issued at 353 PM EDT Mon May 19 2025 Upper level low is expected to hang across the northeastern US for the remainder of the week and into the weekend. This will keep the Ohio Valley within a cooler northwest flow. A few perturbations look to move through on Thursday which may bring a few showers to the northeastern sections of the forecast area. Drier weather looks likely for Friday and into Saturday. Highs Thursday look to warm into the middle 60s with overnight lows in the upper 40s to the lower 50s. Highs on Friday will be similar with readings in the middle 60s. Lows Friday night will drop into the upper 40s to the lower 50s. A continued moderation of temperatures is expected for Saturday with highs in the 65-70 degree range. Lows Saturday night will be in the low-mid 50s. By Sunday and into Monday, upper level ridging will start to build into the region as the upper level low over the northeastern US pushes off to the northeast. Unsettled weather is likely to develop from the southern high Plains southeastward into the Mid-South. Scattered showers and storms may move back into the region by late Sunday, but more likely Monday. For now, chance PoPs from the blend look good here. Highs Sunday look to warm into the upper 60s to the lower 70s, with highs on Monday around 70. && .AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/... Issued at 103 AM EDT Tue May 20 2025 Impacts: - Rounds of Showers and Thunderstorms during this TAF period will result in rapid changes to VFR cigs to MVFR/IFR conditions as storms pass across the TAF sites. - Wind gusts of 35+ knts possible in storms - Confidence is high for rounds of storms today. Discussion: Convection upstream of the TAF sites is poised to push across toward Central KY as a warm front, ahead of low pressure over the middle Mississippi Valley, lingers near the OH river. The lingering front will act as focus for TSRA's this TAF period. CI debris blow off was found across Central KY this morning, providing VFR Cigs. HRRR suggests several wave/rounds of showers and storms passing across the area the first arriving toward 09Z-12Z. This wave will be the weakest and confidence here is lowest. HRRR suggests much better organization with rounds of TSRA late this morning and again late this afternoon. As these lines quickly move across the TAF sites, SVR Storms will be possible with strong wind gusts and IFR CIGS and visibility as they pass. && .LMK WATCHES/WARNINGS/ADVISORIES... KY...Flood Watch from Tuesday afternoon through late Tuesday night for KYZ026>028-039>042-045>049-053>057-061>067-070>078-081- 082. IN...None. && $$ SHORT TERM...NWS LONG TERM....NWS AVIATION...JP ####018004555#### FXUS64 KMRX 200503 AFDMRX Area Forecast Discussion National Weather Service Morristown TN 103 AM EDT Tue May 20 2025 ...New AVIATION... .SHORT TERM... (This evening through Tuesday Night) Issued at 259 PM EDT Mon May 19 2025 Key Messages: 1. Increasing confidence in strong to severe storms for Tuesday afternoon into the early overnight hours. Damaging winds, large hail, and a few tornadoes are all possible. Make sure to have multiple ways to receive watch and warning information and stay weather aware. Discussion: A few showers and storms continue to traverse across the forecast area this afternoon, with moderate bulk shear attempting to support a more marginal thermodynamic profile with MLCAPE near 1500 J/kg near the TN/NC border, with 1000 J/kg or less elsewhere. Overall, the threat for a strong or isolated severe storm through the rest of the afternoon is trending lower as outflow from on- going convection stabilizes the atmosphere. As we head into Tuesday, a negatively tilted trough axis will dig from the PNW into the Mid-Mississippi River and southern Ohio River valleys with an associated surface low near the IA/MO border. A warm front will lift northward through the forecast area late morning into the afternoon followed by a cold front sweeping across the region in the evening to early overnight hours. A return of strong to severe storms is expected with this system. Overall, higher confidence in more scattered to widespread severe weather will be associated with the cold front in the evening. A line of storms is expected to approach the plateau area around 8PM and progress eastward through roughly 2-3AM. While MLCAPE is expected to be just between 1000-1500 J/kg, upward vertical motion associated with H3 jet coupling and a strong swly LLJ of 40kts will promote EBshear near 50kts and 0-1km shear near 25kts. Damaging wind gusts to 70mph, large hail up to 1.25" and a few tornadoes are all possible hazards. There is potential for some activity to develop out ahead of main line, as early as ~4pm, but this is a bit less certain. Nonetheless, make sure to have multiple ways to receive watch and warning information and stay weather aware tomorrow afternoon into the early overnight hours. Isolated flooding concerns will exist for any location that sees multiple strong to severe storms track over the area. Widespread severe threat should really come to an end around 3-4am if not a tad earlier. && .LONG TERM... (Wednesday through next Monday) Issued at 259 PM EDT Mon May 19 2025 Key Messages: 1. Turning much cooler with the coolest day likely to be Friday, then a slow warming to near normal by Monday. 2. Some showers and storms will be around at times during the period, and right now chances look highest Thursday and again for Sunday and Monday. Discussion: Once any early showers/thunderstorms end early Wednesday behind the exiting cold front, cooler and drier air will be pushing in. High temperatures Wednesday will be near seasonal normals. Additional short wave energy will amplify the upper level trough over the eastern US Thursday and Friday, reinforcing the colder air over our area and also bringing a chance for showers mainly Thursday. Friday will likely be the coolest day, with temperatures around 10 to 15 degrees below seasonal normals expected. For the latter periods we will see a slow warming trend, with temperatures approaching seasonal normals again by Monday. We will also see an increase in chances for showers and thunderstorms mainly Sunday and Monday. && .AVIATION... (06Z TAFS) Issued at 102 AM EDT Tue May 20 2025 VFR conditions continue this morning with increasing SW winds on Tuesday afternoon. Probabilities of thunderstorms increase during the afternoon hours with likely thunderstorms across the region after 0z that will impact all TAF sites. && .PRELIMINARY POINT TEMPS/POPS... Chattanooga Airport, TN 88 67 80 59 / 50 80 0 10 Knoxville McGhee Tyson Airport, TN 86 65 78 58 / 50 90 10 10 Oak Ridge, TN 86 65 78 57 / 60 90 10 20 Tri Cities Airport, TN 84 63 77 54 / 60 90 20 20 && .MRX WATCHES/WARNINGS/ADVISORIES... NC...NONE. TN...NONE. VA...NONE. && $$ SHORT TERM...KRS AVIATION...JB ####018003860#### FXUS66 KHNX 200504 AFDHNX Area Forecast Discussion National Weather Service Hanford CA 1004 PM PDT Mon May 19 2025 .UPDATE... Aviation Section Updated && && .KEY MESSAGES... 1. Elevated fire weather conditions will be present today along the West Side Hills and western San Joaquin Valley due to low relative humidity values and increased winds. 2. Above average temperatures return today and will warm through the week. Moderate Heat Risk is expected across the San Joaquin Valley on Wednesday. 3. There is a 50 to 80 percent chance for wind gusts greater than 50 mph in the Mojave Desert Slopes on Thursday. && .DISCUSSION... An upper level trough that passed through central California over the weekend is continuing to progress eastward this morning, resulting in the prevailing flow over our region tracking out of the northwest. As the trough continues further eastward into the contiguous United States, a zonal pattern will set up over the West, with weaker winds aloft only approaching 20 to 25 knots. This zonal pattern normally results in temperatures near average; however, the decrease in winds aloft will create more stagnant conditions, and will result in temperatures a few degrees above average across the area. This pattern is especially prevalent on Wednesday, when afternoon highs are expected to approach ten degrees above normal. There is a 60 to 80 percent chance for temperatures to exceed 93 degrees across the San Joaquin Valley on Wednesday. Recent ensemble runs show a series of two shortwave upper level troughs quickly passing through the Pacific Northwest region on Thursday and Friday, which will bring a cooling trend to central California as winds increase off the Pacific Ocean. However, this being said, temperatures continue to be expected above normal. While temperatures gradually increase through the rest of this week, dew point temperatures will hold steady or fall by a few degrees (depending on location). Current relative minimum relative humidity values hovering near 20 percent are expected to fall below 15 percent as temperatures increase on Wednesday and Thursday. These lower RH values create a more favorable environment for fire development in areas of fine fuels, such as grasses in the San Joaquin Valley. The addition of wind gusts near 20 miles per hour in the San Joaquin Valley resulting from the shortwave trough on Thursday give an increased risk for fire danger, as new fires may be able to spread more quickly. Ensemble guidance isn’t too keen on a particular solution for next weekend, leading to some uncertainty for the conditions for the time frame. The most common solution is for a ridging pattern to build in, resulting in warming temperatures. This is also noted by the Climate Prediction Center which gives a 40 to 50 percent chance for above normal temperatures for our region in the 6 to 10 day period. && .AVIATION... 06Z Update There is a 60 to 80 percent chance for 30 mph wind gusts in the Mojave Desert Slopes through 12Z Tue. Otherwise, VFR conditions will prevail for the next 24 hours across the Central California Interior. && .AIR QUALITY ISSUES... ISSUED: 05/19/2025 14:38 EXPIRES: 05/20/2025 23:59 None. && .CERTAINTY... The level of certainty for days 1 and 2 is high. The level of certainty for days 3 through 7 is medium. Certainty levels include low...medium...and high. Please visit www.weather.gov/hnx/certainty.html for additional information and/or to provide feedback. && .HNX WATCHES/WARNINGS/ADVISORIES... None. && $$ public...Molina aviation....JPK weather.gov/hanford