####018006756#### FXUS61 KRLX 091827 AFDRLX AREA FORECAST DISCUSSION National Weather Service Charleston WV 227 PM EDT Thu May 9 2024 .SYNOPSIS... A cold front will bring additional showers and storms this afternoon and evening, with some storms becoming strong to severe, before promoting cooler weather Friday and the weekend. && .NEAR TERM /THROUGH FRIDAY/... As of 220 PM Friday... Showers and thunderstorms are likely to fire up this afternoon, as west to southwest low level flow increases ahead of an approaching low pressure center and cold front. This will begin with isolated to scattered activity this afternoon, followed by a segmented line of convection drifting southeastward this evening into tonight. Clouds were limiting heating across much of the middle Ohio Valley, versus areas nearer and in the mountains. With the opposite pattern in terms of bulk shear, near 60 kts west but down around 40 kts east integrated 0-6 km, overall severe potential is marginal. Also, modest low level storm relative helicity peaking in the 150-200 m2/s2 range will also support some rotation in more organized cells, like within any line segments later on. Pockets of one hour flash flood guidance values of an inch or less, particularly over the middle Ohio Valley, make such areas vulnerable to excessive runoff from any heavier thunderstorm, but vegetation nearing full growth has proven to be a mitigating factor this week. Cooler air and low clouds roll in behind the cold front tonight, and Friday will be a noticeably different day with the low overcast in place. Showers are possible in the afternoon as a mid-upper level short wave trough crosses, but instability, if any, will be limited. After one last warm afternoon for a few days, central guidance reflects cooling from northwest to southeast behind the cold front tonight, and a noticeably cooler day on Friday with lower 60s most of the afternoon across the lowlands, actually below normal for this time of year. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... As of 225 PM Thursday... Precipitation ends from west to east Friday night as transient ridging builds into the region ahead of a northern stream disturbance approaching during the day Saturday. With relatively cool air left in the wake of the Friday system along with relatively early arrival of associated cloudiness, won't realize very much surface heating. Still, should be able to generate some conditional instability, perhaps 500J/kg in the presence of rather stout deep layer shear of 40 to 50KTs by Saturday afternoon. With rather cool air aloft, graupel showers are likely, with some stronger cores also possible yield strong to perhaps marginally severe wind gusts. && .LONG TERM /SUNDAY THROUGH THURSDAY/... As of 225 PM Thursday... Ridging building into the region yields mainly dry conditions from late Sunday afternoon through Monday. Deep southwesterly flow associated with the next southern stream system will begin to advect moisture back into the region Monday afternoon into Monday evening. Upper level forcing arriving late Monday afternoon into early Tuesday morning will yield an uptick in precipitation coverage. Given the low amplitude of this feature and varied model timing, confidence is not especially high. Transient ridging builds back into the region briefly Wednesday before another system arrives Thursday. Severe risk through this period appears low given a relatively weak flow regime. && .AVIATION /19Z THURSDAY THROUGH TUESDAY/... As of 220 PM Thursday... Stratocumulus has scattered out or lifted out of MVFR for the most part, although brief MVFR ceilings are still possible this afternoon. Showers and thunderstorms are likely to fire up this afternoon, ahead of a low pressure system and cold front, already producing scattered showers in east-central Ohio early this afternoon. MVFR to briefly IFR conditions can be expected directly beneath any thunderstorm, with gusty winds also possible in and near the storms. Showers and thunderstorms will diminish after sunset, but onset and ending timing will generally be earliest northwest /PKB/ and latest southeast /BKW/, as the low pressure system and cold front progress southeastward through the area tonight. Stratocu will lower to MVFR and then even IFR behind the cold front overnight tonight, with MVFR ceilings persisting through Friday morning. BKW may not quite lower to IFR until the end of the TAF period, 18Z Friday. There may also be MVFR visibility in mist/drizzle overnight into Friday morning, possibly lowering to IFR at times. Light southwest flow, albeit with the occasional gust here and there, ahead of the cold front this afternoon will become west to northwest behind it tonight, and become a bit gusty at least at BKW by dawn Friday. Moderate west to southwest flow ahead of the front this afternoon will become moderate west to northwest behind it tonight, and then light northwest on Friday. FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 18Z FRIDAY... FORECAST CONFIDENCE: Medium. ALTERNATE SCENARIOS: Timing of ceiling and visibility restrictions may vary from forecast. Winds will fluctuate. EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY OF WFO FORECAST TO AVAILABLE MODEL INFORMATION: H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS. L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL. UTC 1HRLY 18 19 20 21 22 23 00 01 02 03 04 05 EDT 1HRLY 14 15 16 17 18 19 20 21 22 23 00 01 CRW CONSISTENCY H H H H H H H H H H H H HTS CONSISTENCY M H H H H H H H H H H M BKW CONSISTENCY H H H H H H H H H H H H EKN CONSISTENCY M M H H H M M H H H M H PKB CONSISTENCY H H H H H H H H H H H H CKB CONSISTENCY M M M H H H H H H H H H AFTER 18Z FRIDAY... Lingering IFR conditions behind the cold front remain possible along the mountains Friday afternoon. && .RLX WATCHES/WARNINGS/ADVISORIES... WV...None. OH...None. KY...None. VA...None. && $$ SYNOPSIS...TRM/JP NEAR TERM...TRM SHORT TERM...JP LONG TERM...JP AVIATION...TRM ####018013296#### FXUS64 KHGX 091827 AFDHGX Area Forecast Discussion National Weather Service Houston/Galveston TX 127 PM CDT Thu May 9 2024 ...New AVIATION... .SYNOPSIS... Issued at 340 AM CDT Thu May 9 2024 Early season heat takes center stage for one more afternoon, then we look warily northwest to see what...if anything...comes our way tonight bearing any threat for severe storms. Temperatures will tone down going into the end of the week after a weak cold front, turning the focus of the forecast to rainfall potential Sunday into Monday. A few key takeaways: - Look for peak heat index values to again rise to around or over 100 degrees away from the Gulf this afternoon thanks to humid conditions and high temperatures around 90 degrees. This first multi-day stretch of above-average heat is a good chance to stretch out those heat safety muscles, as summer is rapidly arriving. - Meanwhile, over North and Central Texas, we expect storms to get going late in the afternoon, and make their way eastward. In general, the highest threat is to the north, with a less favorable environment southward. A threat level 3 of 5 (Enhanced Risk) exists northward of a line roughly from College Station to Livingston. A threat level 2 of 5 (Slight Risk) exists southward of there to roughly I-10. A threat level 1 of 5 (Marginal Risk) is in place for much of the area south of I-10. The primary threat in the afternoon will be large hail, potentially even significant hail larger than 2 inches in diameter. The primary threat will shift more towards damaging wind gusts in the evening. An isolated tornado is a lesser concern, but cannot be ruled out. - We're also still watching the potential for locally heavy rainfall on Sunday and Monday from another round of showers and thunderstorms. WPC indicates a Marginal to Slight risk of excessive rain each day (threat levels 1 and 2 of 4). Continue to monitor the forecasts heading into the weekend for the latest analysis. && .SHORT TERM... (Today through Friday Night) Issued at 340 AM CDT Thu May 9 2024 Oh, it's starting to feel a lot like summer...everywhere you sweat... We've been talking about this for several days now, so I don't want to risk beating this point too frequently, but early season heat continues to be a sneaky threat for heat exhaustion and heat stroke, as the numbers are lower than we see in the teeth of summer, but our bodies aren't quite acclimated to it yet. The same situation is there today, thanks to highs again around 90 degrees with a peak heat index around or just over the century mark (except on the Gulf, things look a bit cooler there). Hang in there, today will be last day with widespread above average heat, and things will continue to moderate just a bit into next week. But if you love it hot, don't worry - there's a lot more where this came from. Of course, with temperatures this high and ample moisture in place, evidenced by widespread dewpoints in the middle 70s, we've got a deep pool of thunderstorm fuel in place, but like yesterday, we'll largely be in search of a mechanism for initiation. That mechanism exists off to the northwest of our area along a dryline, and eventually, an incoming "cold" front. Eventually, storms that fire away from our area, may become a concern as they push eastward off the initiating boundary. mean HREF SBCAPE values exceed 4000 J/Kg in our northwest closest to the initiation region. The max values start to get a little stupid, exceeding 5000 J/Kg. Should any storms manage to push their way in from the west/northwest, that instability combined with shear in excess of 30 knots should sustain any storms that come into the area. The big question again is...do any storms get in here at all? Convective initiation should again focus well to the north of the area, where there's much better forcing. Still, late this afternoon into the overnight hours does look to feature a small shortwave trough passing aloft, which could be enough to get some isolated storms going. Given the big amounts of instability at play, the initial threat...mostly out of our area, but perhaps sneaking into the northwest if they move in early enough, will be large hail, potentially greater than 2 inches in diameter. Eventually, as the sun sets, and we lose that pool of extreme instability, we'll likely see any development there is grow upscale along/ahead of the incoming front for the overnight hours. The threat should then transition from hail to large swaths of damaging straight line wind gusts, though a brief tornado can't be totally ruled out either. One important note with today's setup - because our primary question is convective initiation, many of us, even in the enhanced risk area, may well see nothing at all. Can't have severe storms if there aren't any storms to begin with! But also, with our north on the edge of the pool of extreme instability, if we get a couple storms to pop up, we can expect them to cook. Any storms that do make their way through the area should be moving on to the east and out of our portion of Southeast Texas not too long after midnight. Behind them, a weak "cold" front looks to push its way through the area to the Gulf by Friday morning. It will help tamp down temperatures modestly, but do not get too excited here. Cold air advection behind the front will be limited, and while the post-frontal airmass will also be modestly drier, our main achievement will be to see dewpoints drop out of the 70s. Indeed, this time of year, while we can expect to see some slight cooling well inland, the day after a cold front on the coastal plain is often just as...or even a bit hotter than the day before, thanks to seeing more sun and the more efficient heating of drier air. I was pleasantly surprised to see the NBM actually catch onto that for once, and mostly rolled with its temperatures rather than trying to Frankenstein together an inland and a coastal high temperature forecast. Finally, we should see whatever modest relief we're going to see behind this front settle deeper into the area Friday night. Except within a county of so of the Gulf, we can expect low temps Friday night to make it below 70 degrees. && .LONG TERM... (Saturday through Wednesday) Issued at 340 AM CDT Thu May 9 2024 Surface high pressure slides east through the Southern Plains on Saturday, allowing onshore flow to gradually return during the day. Remnants of the frontal boundary will gradually lift north as a warm front Saturday night, suppling additional moisture and bringing PWs of 1.5-2.0 inches. Lifting from the boundary will be further supplemented by weak impulses aloft from a cutoff low over the Desert Southwest. This should produce scattered showers and storms, beginning over out west/southwestern counties early Sunday and spreading to the remainder of SE Texas later that morning. Around this point, the closed low/trough will be near the TX/OK Panhandle, providing additional lift as stronger impulses pass over the area. Combining this forcing with the lifting warm sector should allow for more widespread showers/thunderstorms to develop during the afternoon/evening. Forecast soundings also suggest high precipitation efficiency in this environment, favoring the potential for locally heavy rainfall. WPC has portions of SE Texas under a Slight (level 2/4) to Marginal (level 1/4) Risk of excessive rainfall for Mother's Day on Sunday. Shower/storm activity should briefly decreases during the overnight hours as the main forcing axis from the upper level trough slides eastward towards the Mississippi River Valley. Global models indicate another shortwave trough passing overhead on Monday, bringing an additional round of thunderstorms. Forecast soundings seem to suggest sufficient shear & instability available for stronger storms to develop during this period. Additionally, these storms will still be capable of producing locally heavy rainfall, and thus WPC has maintained a Slight (level 2/4) to Marginal (level 1/4) Risk of Excessive rainfall over portions of SE Texas on Monday. Forecasted rainfall totals from Sunday through Monday night will be around 1-3" with the highest amounts expected generally north of the I-10 corridor. Rain chances diminish into early Tuesday morning as PWs drop under 1.0" in the wake of the shortwave & upper trough. This will bring calmer, more benign weather for Tuesday with highs in the 80s to lower 90s. However, moisture begins to return Tuesday night, with rain chances returning on Wednesday and continuing late into the week. && .AVIATION... (18Z TAF Issuance) Issued at 109 PM CDT Thu May 9 2024 A mix of IFR to MVFR cigs/vis currently occuring across SE Texas sites. Visibility restrictions due to smoke transport from Mexico will continue for much of the region through at least late afternoon or early evening and is expected to gradually disperse early tonight. Even with a strong cap in place, a weak shortwave passing through has helped initiate iso SH/TS activity over the area and is expected to continue during the next few hours. Later this evening into tonight, storms developing along a cold front to our N-NE is expected to move into the Brazos Valley and Piney Woods region. Based on the environmental conditions, some of these storms could be strong to severe and will be capable of producing large hail and damaging winds. Iso tornadoes cannot be ruled out either. The sites that have the greatest risk for severe storms are CLL/UTS/CXO, but may even extend into SGR/IAH although they are expected to dissipate as they move S-SE and approach the I-10 corridor. The cold front is expected to quickly move across SE Texas tonight, thus, a northerly wind shift along with an increase in wind speeds can be expected during the overnight to early morning hours. That being said, N-NE winds will remain at 10-15 KTS for much of the day Fri. Skies are expected to lift and scatter out near sunrise. 24 && .MARINE... Issued at 340 AM CDT Thu May 9 2024 Light to moderate onshore flow is expected today ahead of a frontal boundary. This persistent fetch will bring seas of 3-6 feet in the Gulf and elevated tide levels along the coast. High flows from rivers, creeks and streams will lead to above normal water levels in the bays and intercoastal water way this week, which may make navigation difficult at times. A cold front will push offshore during the early morning hours of Friday. Moderate offshore winds behind the front may warrant caution flags into the weekend. Onshore flow returns Saturday night/Sunday as a warm front moves onshore. Periods of showers and thunderstorms will be possible from Sunday through early next week. && .HYDROLOGY... Issued at 426 PM CDT Wed May 8 2024 Updated 340 AM CDT Thu May 9 2024 A slightly higher chance for thunderstorms exists again today, but is still not expected to be widespread enough to result in any additional areal flooding. Although there have been decreases in the water levels along the rivers, some will remain swollen for days (possibly weeks). Do NOT go around barricades and stay out of the floodwaters. Do NOT return to homes until officials deem that it is safe. River flooding continues for parts of Southeast Texas, particularly along portions of the Trinity river. The following river points are at Moderate or Major flood stage as of Wednesday afternoon: - Trinity River (Liberty): Major Flood Stage - Trinity River (Goodrich): Moderate Flood Stage - Trinity River (Moss Bluff): Major Flood Stage - Trinity River (Riverside): Moderate Flood Stage Remember to heed any instructions from your local officials and to never travel through flooded areas or roadways. TURN AROUND, DON'T DROWN. Please monitor updated forecasts via the NWS AHPS website and/or the new NWS NWPS webpage (https://water.noaa.gov/) as the river flood threat continues.  Also of note is that the downstream runoff from the previous rainfall will cause continued rises along the Brazos River through the end of the week. 24/Luchs && .CLIMATE... Issued at 340 AM CDT Thu May 9 2024 Hobby Airport keeps the record high minimum train rolling, breaking the daily record again yesterday. The low of 78 degrees eclipsed the previous record of 77, set all the way back in 2022. && .PRELIMINARY POINT TEMPS/POPS... College Station (CLL) 89 69 83 64 / 20 40 10 10 Houston (IAH) 90 72 88 68 / 30 20 10 10 Galveston (GLS) 82 75 84 72 / 30 10 10 0 && .HGX WATCHES/WARNINGS/ADVISORIES... TX...None. GM...None. && $$ SHORT TERM...Luchs LONG TERM....03 AVIATION...24 MARINE...03 ####018006345#### FXUS66 KPQR 091828 AAA AFDPQR Area Forecast Discussion...UPDATE National Weather Service Portland OR 1128 AM PDT Thu May 9 2024 .SYNOPSIS...A stout ridge of high pressure continues to build across the region the latter half of the week resulting in a prolonged period of dry weather and rapidly warming temperatures day to day. It still appears near record breaking heat is in store Friday into Saturday's daytime highs climb in the mid 80s to near 90 across the inland valleys. Cooler onshore flow returns Saturday night into Sunday resulting in slightly cooler temperatures for the early to middle portion of next week albeit still near to slightly above seasonal norms. && .SHORT TERM...THURSDAY THROUGH SATURDAY...Ridging continues, with essentially no cloud cover throughout the CWA as of 3am Thursday. Going forward through Thursday and Friday the ridge will continue to amplify, tilting eastward into British Columbia and increasing offshore flow over the Pacific Northwest. Temperatures warm going into Thursday, with the warmest temperatures on Friday and Saturday afternoon. Given the development of low-level offshore flow and surface thermal trough building overhead as well, confidence is very high(90-99%) in afternoon temperatures reaching into the low 80s across the inland valleys Thursday followed by another 6-10 degree jump into the mid/upper 80s to near 90 Friday. Temperatures across the Willamette Valley, SW Washington, and other inland valleys appear very similar on Saturday compared to the day prior (Friday) - both days present a 40-60% chance to break 90 degrees in the Portland/Vancouver Metro according to the NBM. The coast will be more uncertain with regards to temperature, as model guidance is beginning to show the thermal trough shifting inland Saturday, trending towards cooler temperatures. High temperatures on Friday look to remain around the low 70s, but Saturday sees much cooler high temperatures into the mid 60s. Saturday looks to only have a 10-30% chance of being above 70 at the coast. These unseasonably warm temperatures will no doubt cause some people to flock to the rivers, lakes, and ocean beaches of SW Washington and NW Oregon. It is important to remember that rivers and lakes remain dangerously cold with water temperatures mainly in the 40s. Such temperatures can easily cause cold water shock for those without proper cold water gear. The bright sun and warm temperatures can make the cold water look refreshing, but the consequences of jumping in could be deadly. Be sure to bring a life vest and be extremely cautious around area rivers, especially given the swift currents also in place! -Schuldt/JLiu .LONG TERM...Sunday through Wednesday...More widespread cooling is expected on Sunday as the ridge of high pressure withers in response to a weak upper-level shortwave pressing eastward towards the coast. The axis of the near surface thermal trough also shifts east of the Cascades into the Columbia Basin - widespread westerly onshore flow returns. The marine layer will likely remain too shallow for much in the way of morning cloudiness inland through Sunday, but the upper ridge may weaken enough for some low clouds to push into the inland valleys for a few hours Monday morning. Cannot rule out patchy light drizzle at the coast Sunday night into Monday morning as well, especially given the weak upper- level shortwave progressing overhead providing some added support. WPC cluster analysis is beginning to move more towards a solution favoring ridging re-developing by the middle of next week. Around 80% of ensemble members display relatively strong ridging by Wednesday next week, allowing temperatures to climb back into at least the upper 70s to low 80s. Still around a 20% chance of another trough developing, which would bring more seasonable temperatures and light rain showers back to the area. -Schuldt/JLiu && .AVIATION...High pressure will remain over the region, with dry northerly flow aloft. This will maintain VFR under mostly clear skies. Low level northerly flow will kick up by midday, with winds gusting 15 to 25 kt. Winds ease tonight, with VFR continuing. PDX AND APPROACHES...High pressure will maintain VFR with variable high clouds. Will see north to northeast winds by midday, with gusts 15-20 kt for the afternoon into early evening. && .MARINE...No big changes, as strong high pressure remains anchored offshore. Meanwhile, thermal trough will hug the south Oregon coast, building northward later today into tonight. With this pattern, will maintain gusty northerly winds on the waters, with gusts 20 to 25 kt today north of Cascade Head, and gusts 25 to 30 kt to the south. As thermal trough builds north later today into tonight, will see winds near shore relax back below 20 kt. Gusty winds will continue offshore well into overnight hours. Thermal trough will push the tighter pressure gradient further offshore later tonight and Fri, as the thermal trough expands northward along the north Oregon coast. This will push the gusty north winds farther offshore, with lighter east to northeast winds on most of the coast waters, especially nearshore. But, with the thermal trough shifting back to the Coast Range Fri evening, will see wind flip back to north or northwest Fri evening. Seas mostly 5 to 8 ft today into tonight, with the higher seas more choppy as being dominated by the gusty winds. Seas stay at 5 to 6 ft into Sat. Thermal trough will shift much farther inland on Sat and Sun, with north to northwest winds returning to the coastal waters. Will not be as strong, but generally gusts 20 to 25 kt at times in the afternoons and early evenings. Seas mostly 6 to 8 ft. && .PQR WATCHES/WARNINGS/ADVISORIES... OR...None. WA...None. PZ...Small Craft Advisory until 11 PM PDT this evening for PZZ251>253- 271. Small Craft Advisory until 5 AM PDT Friday for PZZ272-273. && $$ www.weather.gov/portland Interact with us via social media: www.facebook.com/NWSPortland www.twitter.com/NWSPortland