Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/10/22

Area Forecast Discussion
National Weather Service Gray ME
949 PM EDT Tue Aug 9 2022 .SYNOPSIS... A cold front will gradually sink south of the region tonight... allowing much cooler air to filter into the region for the day on Wednesday. Another cold front will approach the region on Thursday with some scattered showers. The weather turns drier and cooler for Friday and Saturday as low pressure passes well east of New England. A slow warm up is expected next week. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... 945PM Update...No significant updates with this package, mostly just tweaked timing of cloud cover and trimmed back pops a bit. Backdoor front and marine push is just about reached the CT River Valley. This marine push will lead to a cool and moist night for the entire region, kept the mention of drizzle, but mostly confined to the mountain areas with NE upslope winds favoring the higher terrain. Some fog is possible but not expecting that much with the low level stratus deck firmly in place across the region already. A few spotty showers remain, but only a few hundredths of precip is expected before shower activity mostly ends after midnight. 630PM Update...Backdoor cold front is currently pushing into the Merrimack River Valley at this hour. It will finally bring relieve and end to the historic heatwave that impacted Southern New Hampshire over the past week. The marine airmass behind the front is cool with most areas behind the front in the mid to upper 60s. With the strong Canadian Maritime airmass push, upslope drizzle is expected in the mountains with low clouds behind the front. A few spotty showers are developing on the frontal boundary, but overall just some hit and miss rainfall, with no drought relieve type of rain with this boundary passage. The wavering frontal boundary with waves of low pressure tracking along it will finally shift south of the area for good tonight. Before the boundary shifts to our south it will provide a focus for showers and possibly a couple of thunderstorms across southern New Hampshire and SW Maine. The latest RAP analysis shows a wedge of MLCAPE in the 1000 to 1500 J/kg range juxtaposed with around 35 kts of effective shear across southern New Hampshire into York and Cumberland Counties. Latest radar shows a few showers tracking across eastern NH and SW Maine with the bulk of lightning activity remaining to our south over Massachusetts. CAMs have been quite bearish on convective coverage where there is currently sufficient instability through this evening advertising more in the way of showers than thunderstorms. Given recent trends in CAM guidance and trends in a boundary pushing SW down the Maine coast... forecast thinking is along the lines of scattered showers with occasional instances of thunder rather than scattered strong thunderstorms through sunset. By sunset the boundary will be south of the area with low level easterly flow overspreading the remaining southern areas. This will usher in cooler air and ending the oppressive heat and humidity for all areas. Tonight low level easterly flow will continue with mostly cloudy skies. BUFKIT soundings most of the area will see low level saturation below 800 mb although dewpoint depressions at the surface look to be large enough to inhibit widespread fog. Current forecast thinking leans more towards low ceilings with patchy fog across northern valleys and isolated showers or possibly drizzle. Lows tonight will drop into the 50s across the north to the low 60s across the south. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... Wednesday will be much cooler with highs ranging from the upper 60s north to upper 70s across southern New Hampshire and the CT Valley. Skies will be mostly cloudy to start with thinning cloud cover going into Wednesday evening. Broad cyclonic flow aloft will bring the threat of a stray shower while most areas will be dry. Troughing over eastern North America starts to deepen Wednesday night with skies turning mostly cloudy towards Thursday morning. There will be slight chances for showers across the southern half of the area along with patchy fog in sheltered inland locations and along the coast. Lows will range from the mid 50s north to mid 60s south. && .LONG TERM /THURSDAY THROUGH TUESDAY/... High Impact Weather Potential: Minimal. --Pattern and Implications-- The long term forecast period opens with a pattern change as longwave troughing over eastern Canada drops into the northeastern United States to end the week. Another longwave trough will reside across the eastern Pacific with longwave ridging near the spine of the Rocky Mountains. This overall flavor to the mid and upper level flow pattern will remain relatively unchanged through the weekend and into early next week. The aforementioned trough sharpens overhead this weekend with low pressure developing east of the region and moving into the Canadian maritimes. Beyond this into early next week...the ensemble consensus favors shifting the longwave trough axis to a position just west of our region. Thus..the temperature trend will be downward into the weekend with the arriving trough and then slowly back upward early next week as heights rise. return to significant heat/humidity is expected in the long term given this overall change in the synoptic pattern. As for precipitation chances...some chances will exist to open the period on the front end of the arriving trough/associated cold front. Through the weekend...though the ensemble consensus does not favor much in the way of widespread upper low overhead suggests at least a chance for a sprinkle or shower. We will likely turn dry for a period late Sunday into Monday as the trough re-orients further west with increasing moisture portending more precipitation chances towards the very end of this forecast period. --Daily Details-- Thursday - Friday: Period opens with a cold front over the eastern Great Lakes as a longwave trough builds towards the region. 1.5 PVU surface jet streak over 100kt will be anchored over northern Maine which...combined with upstream trough should allow for cyclogenesis south and east of New England. Moisture builds along the advancing cold front with PWATs around 1.5" in a ribbon along the front. With the mid/upper level flow amplifying and surface low taking shape southeast of New England...the forward progression of the front will slow...and provide a focus for shower development despite more significant forcing being located offshore. Given the offshore low development...expect a decent amount of cloudiness even well ahead of the while some destabilization is not currently expect a significant thunderstorm threat. Airmass ahead of the front is warm /T8s nearing 15C/ but cloud cover will limit heating with mid 70s to lower 80s likely for highs. Front washes out as it crosses the region Thursday night with northerly flow bringing drier air into the region on Friday with T8s falling towards or a bit below 10C...which should keep mountain locations right around 70...with a downslope component further south allowing highs in the upper 70s to around 80 to the south. This will set the stage for much cooler lows Friday night with clear skies and diminishing winds allowing lows to fall into the 40s in the mountains with 50s to the south and east. Saturday - Sunday: Trough axis will be directly overhead to start the forecast period Saturday with this trough sharpening and spawning low pressure south of Nova Scotia which remains well east of the region. The upper low moves from being overhead Saturday to north and east of the region on Sunday. T5s at the core of this low fall to around -15C though the westward tilt of the system with height suggests some warmer air below this level. Thus...despite cool temperatures aloft...model profiles suggest a capped airmass with little signal for shower chances. There remain some differences on the overall evolution of the core of the upper low and it/s interaction with the downstream surface low...but can/t rule out a shower either afternoon...especially in the mountains. T8s will remain at or a bit below +10C on Saturday...moving just above +10C for Sunday. Therefore a much cooler weekend is in store than the previous with highs mostly in the 70s to around 80 from north to south Saturday warming into the mid 70s/lower 80s for Sunday under partly cloudy skies. Monday - Tuesday: Heights begin to rise across the northeastern United States with longwave trough relaxing before reloading from the west. High pressure at the surface should allow for a dry day Monday before precipitation chances slowly increase on Tuesday depending on the speed of the reinforcing shortwave trough. T8s will remain in the 11-13C range...perhaps warming just a bit from Monday into Tuesday. This should result in seasonable temperatures...with highs in the 70s in the mountains and lower 80s from the foothills south. && .AVIATION /02Z WEDNESDAY THROUGH SUNDAY/... Short Term...Frontal boundary across southern Maine and New Hampshire will shift south tonight with cigs lowering to IFR/LIFR thresholds and patchy fog bring vsby restrictions to all terminals. Cigs lift to MVFR thresholds Wednesday morning and VFR thresholds Wednesday afternoon. Low cigs and patchy fog will likely bring IFR to LIFR conditions again Wednesday night. Long Term...Showers and an isolated thunderstorm are possible Thursday afternoon and Thursday night which will allow for scattered MVFR restrictions. Beyond this VFR conditions should dominate the Friday-Sunday period outside of overnight fog potential each night at HIE/LEB. && .MARINE... Short Term...Winds and seas are expected to remain below SCA thresholds through Wednesday night. Frontal boundary dropping south across the waters this evening will shift winds out of the NE tonight with winds shifting out of the E to SE late Wednesday and then S Wednesday night. Long Term...Winds and waves are currently expected to remain below SCA levels through the period. Low pressure is expected to pass well south and east of the waters late Friday through early Saturday. If the track of this low were to move west somewhat...a period of SCAs would be possible due to gusty northerly winds either Friday night or potentially on Saturday. && .GYX WATCHES/WARNINGS/ADVISORIES... ME...None. NH...None. MARINE...None. && $$ SYNOPSIS...Arnott NEAR TERM...Dumont SHORT TERM...Schroeter LONG TERM...Arnott AVIATION...Arnott/Schroeter MARINE...Arnott/Schroeter
Area Forecast Discussion
National Weather Service Paducah KY
506 PM CDT Tue Aug 9 2022 .UPDATE... Issued at 501 PM CDT Tue Aug 9 2022 Updated Aviation discussion for 00Z TAF Issuance. && .SHORT TERM...(Tonight through Thursday night) Issued at 318 PM CDT Tue Aug 9 2022 Pinpointing times/locations of best chances of convection this afternoon through Wednesday remains challenging as models have been overdoing the coverage thus far. At this time, a blend of the more extensive coverage RAP and minimal coverage HRRR is a decent solution through this evening, resulting in scattered showers and thunderstorms across our entire region through mid evening. Loss of heating should result in more isolated to widely scattered showers and thunderstorms overnight. The cold front helping to set off this activity is currently sinking into our far northern counties, and models show the front bisecting the PAH forecast area basically along the Ohio River into southeast Missouri by 12z Wednesday. The highest chances will be along and southeast of the front, which will put the best chances across west Kentucky by late tonight and through the day Wednesday. Models show the frontal boundary meandering across, then just south of west Kentucky into early Thursday. Chances of showers and storms will continue across our entire area Wednesday morning, then dry conditions will return to our northwest counties Wednesday afternoon. Chances will continue primarily across just west Kentucky Wednesday evening, with convection ending during the overnight hours. Isolated showers and storms will again be possible across southern portions of the Pennyrile region on Thursday, then Thursday any chances will move away from our area. The passage of the front will result in temperatures being a little below normal, and dew points will gradually drop from the lower to middle 70s today, to the upper 60s to lower 70s Wednesday, to the upper 60s area wide Thursday. .LONG TERM...(Friday through Tuesday) Issued at 318 PM CDT Tue Aug 9 2022 Cooler than normal temps are in store to end the week as the FA will be sandwiched between a deep 500 mb trough along the East Coast and a large 500 mb ridge centered over the Plains. This will establish north to northeast winds at the sfc supporting dry conditions and lower humidity in addition to the cooler temps. With sfc high pressure moving across the Great Lakes region on Friday, highs will be in the lower 80s and dewpoints well into the 60s. For Friday night, light variable winds combined with mostly clear skies will allow for some radiational cooling to occur with lows nearing 60 degrees. Dewpoints may even reach the upper 50s along I- 64, meaning conditions will be ideal to give the AC a much needed break! Saturday will be the nicest day of the weekend as highs will be similar to Friday in the low to mid 80s with sufficient diurnal heating. Heading in Sunday, dry conditions along with slightly warmer temps is still looking likely as the latest 12z GFS which has been the most progressive in bringing QPF to the FA has slowed down quite a bit. With the best theta-e and 850 mb warm moist advection now holding off until Monday, it is more likely any slight chances of pcpn progged by the NBM hold off until later Sunday night across our northern counties. The big forecast question for Monday is if a 500 mb impulse rounds the corner of the 500 mb ridge over the Plains as this would bring a better risk for showers and thunderstorms during the day. Chances for pcpn continue into Tuesday as a series of disturbances will approach the FA from upstream. && .AVIATION... Issued at 501 PM CDT Tue Aug 9 2022 The surface front looks to extend from near KOWB, to just south of KPAH-KCGI. Active convective chances persist near its boundary, but radar shows mainly VC mention from KEVV-KOWB for a short while longer is perhaps best, with silent chances thereafter. MOS guidance suggest potential CIGS/VSBYS restrictions overnight with fog/low cloud, so we`ve included that in this issuance and will monitor trends behind the front as the night progresses. The boundary`s still near vicinity tmrw will serve as a focus for showers/storms again, with diurnal fueling. && .PAH WATCHES/WARNINGS/ADVISORIES... IL...None. MO...None. IN...None. KY...None. && $$
Area Forecast Discussion
National Weather Service Pendleton OR
456 PM PDT Tue Aug 9 2022 .Updated Aviation Discussion. Short term...Today through Thursday... Active weather today and into tomorrow morning. Current radar is showing a robust cell down in Deschutes County that is putting off a few good pulses of lightning. A Red Flag warning is in affect for the abundant lightning expected through Central Oregon until 9 PM tonight. Short term HRRR model is showing some decent QPF and PWAT values, so these storms will likely produce some moderate to heavy rainfall rates. Strong outflow winds will also accompany any developing storm cells, as some observations taken earlier in the day have reached near 50 mph. The SREF/HRRR short term models as well as the GFS/ECMWF and NAM models are in fairly good agreement with the placement of the low off the coast. Currently the low is sitting off the coast of Northern California and the leading edge is just onshore, while the ridge has begun to breakdown. The far edge of the ridge is pressed right up against the low creating the perfect combination to draw some of the monsoonal moisture from the Four Corners into our area. The HRRR is showing some significant CAPE values over much of Central OR and moving into the eastern region of the CWA by tomorrow morning. Highs will be the mid 80s to 90s, a bit lower than originally forecasted due to the intermittent cloud cover and increased winds. The rest of today we will see the storms continue to progress north and eastward through the region. VIS satellite is showing a nice clearing across much of the Basin, so daytime heating will allow for some convective build up as the moisture moves over the region later this afternoon. Chance of showers and thunderstorms for much of the southern and eastern portion of the CWA and a slight chance of showers elsewhere. Highs will be the mid 80s to 90s, a bit lower than originally forecasted due to the earlier cloud cover this morning. Wednesday, the models are still in tight agreement with the placement of the low. They are showing the low will be just of the coast of Oregon and slightly closer to shore. With the moisture still being pushed in from the south, there is a slight chance of showers mainly over the Northern Cascade crest and eastern Oregon in the morning. By late morning as instability increases with sunrise, chances of thunderstorms will increase over those same locations until tomorrow night. Dry conditions will prevail through the remainder of the evening and into the remainder of the forecast period. The remainder of the period will be dry with temperatures in the upper 80s to mid 90s with a few localized 100s and locally breezy winds. Bennese/90 LONG TERM...Friday through Tuesday...Mostly benign weather with above-normal temperatures is currently expected for the long- term period. Ensemble cluster analysis reveals the main uncertainty in the longwave pattern revolves around the progression of the upper- level low currently situated offshore and an impending ridge for Monday and Tuesday. Friday and Saturday, locally breezy conditions are forecast through the Cascade gaps during the afternoon and evening, driven by cross- Cascade thermal and pressure gradients as the upper-level low eventually lifts into British Columbia. With our CWA under diffluent SW flow, could see some shower and thunderstorm development Friday afternoon and again Saturday afternoon across the mountains, provided there is enough moisture, but confidence is low at this time. Flow aloft will weaken should the most likely scenario (unperturbed southwest flow aloft) verify, though clusters do suggest a roughly 25% chance of the upper low just pushing onshore by Sunday. Should the latter solution verify, locally breezy conditions through the Cascade gaps, with slightly cooler temperatures would occur Sunday. Heading into Monday, the most likely solution is ridging beginning to build across the Pacific Northwest, with this trend continuing for Tuesday. Some heat concerns may develop Tuesday and beyond with many ensemble members suggesting 100-110 in the Lower Basin and Foothills of the Blue Mountains. Plunkett/86 .AVIATION...00Z TAFS...VFR conditions expected through the period with the exception of localized MVFR/IFR categories in and around thunderstorm and shower activity this afternoon into tonight due to decreased visibilities and ceilings. Synoptic winds will subside this evening and tonight before picking back up to 10-20 kts at KDLS, KRDM, and KBDN Wednesday morning and afternoon. Winds will be gusty and erratic in and around thunderstorms, with gusts of up to 50 mph possible. Plunkett/86 && .PRELIMINARY POINT TEMPS/POPS... PDT 68 97 60 91 / 30 20 0 10 ALW 71 98 64 93 / 30 20 10 10 PSC 73 100 67 95 / 20 10 10 0 YKM 67 97 60 94 / 30 10 0 0 HRI 70 99 64 95 / 30 10 0 0 ELN 67 97 61 93 / 20 20 10 0 RDM 57 93 49 90 / 40 0 0 0 LGD 65 94 58 90 / 40 40 20 20 GCD 62 96 56 95 / 60 20 10 0 DLS 68 87 62 93 / 30 10 0 0 && .PDT WATCHES/WARNINGS/ADVISORIES... OR...Heat Advisory until 11 PM PDT this evening for ORZ041-044-049- 050-503-505-507-508. Red Flag Warning until 9 PM PDT this evening for ORZ611-640-642- 644. Red Flag Warning until 6 AM PDT Wednesday for ORZ610. WA...Heat Advisory until 11 PM PDT this evening for WAZ024-026>029- 521. && $$ SHORT TERM...90 LONG TERM....86 AVIATION...86
Area Forecast Discussion
National Weather Service Phoenix AZ
529 PM MST Tue Aug 9 2022 .UPDATE... Updated Aviation section. && .SYNOPSIS... Elevated chances for showers and thunderstorms will continue the rest of the week and into early next week. Occasionally heavy rainfall, localized flash flooding, gusty winds and localized blowing dust remain likely through early next week. High temperatures will remain below to near normal through the forecast period. && .DISCUSSION... The midlevel Monsoon ridge remains optimally located near the S-Cent Rockies with moist E undercutting flow through the mid-upper levels aloft. WV imagery reveals a very moist airmass across the region with a number of E waves/inverted troughs pushing W and NW into/through various parts of the region including N, E and S-SE AZ, SE CA/La Paz Cty, where GOES imagery and radar also indicated an area of scattered showers and storms, with localized flash flooding occurring this afternoon, including I-10 E and W of Blythe. Early afternoon radar also showed widely isolated to scattered distant thunderstorms across the high terrain of N, E and S-SE AZ. Both the E AZ/W NM and S-SE AZ storms were associated with additional, possibly linked E wave(S) advancing from those areas. The latest ACARS soundings showed an anomalously moist airmass with PW maintaining near 1.7->1.9" while mesoscale analysis indicated PW of 1.5->2" and Mean W of 10->14 g/kg across SW-W and S-Cent AZ and into SE CA. MU and SB CAPE had also increased to >1.7-1.8K j/kg around Phoenix and >2k j/kg across the W deserts. In a seemingly virtual repeat of yesterday, HREF members still favor pronounced convection with locally heavy rainfall developing this afternoon across S Gila Cty and near Globe and burn scar areas before descending into the lower deserts and parts of the Phoenix Metro during the evening hours. With the regional Flood Watch now underway through late tonight, and with the WPC Day 1 ERO indicating the large "Slight Risk" area, any convection that develops will have sound potential to produce locally heavy rainfall as well as localized flash flooding. Also like yesterday the HRRR has once again become an outlier and has again backed off on that scenario by both delaying and weakening the convection coming off of the high terrain this evening. This is the result of a festering MCV, light showers and cloudy/mostly cloudy conditions that significantly delayed surface heating this morning across most of the Phoenix Metro. This supported elevated levels of CIN well into the day around Phoenix. However the 12Z HREF ensemble still indicated a gusty SE outflow this evening pushing into the Phoenix metro and N Pinal as well as colliding outflow signals late tonight W-SW of Phoenix. The potential for patchy blowing dust moving NW remains possible, although remains most likely for N Pinal Cty and the SE-E Phx Metro Valley where there is a 10-30% chance of max sustained storm outflow wind speeds of >35 mph this evening. Also like a repeat of yesterday`s progs, tomorrow the HREF and ensembles are in agreement on an increase in storm chances and coverage from E to W across the region with POPs increasing to near 50% for Phoenix and the lower deserts and the E AZ high country, and 20-30% for SW AZ and SE CA. Some HREF members start with some shower activity W of Phoenix in the Wed morning hours moving in from in S-SE AZ. However the main convection will likely start in E-SE AZ associated with the next E wave(S) and will push into the Phoenix Metro and the lower deserts Wed evening. For Wed evening the HREF indicates an even better 30->50% chance of max sustained storm outflow wind speeds of >35 mph from both the S-SE and E and locally dense blowing dust. Also indicated is a >10% chance of sustained max outflow winds >57 mph along the infamous I-10 dust corridor just south or the CWA (or S of Eloy AZ near Picacho Peak). This would likely be followed by locally heavy rainfall and additional localized flash flooding in the high country and the lower deserts. Looking more broadly for the rest of the week and into the weekend, major weather features include the mid level anticyclone centered near Four Corners and a rather deep upper level low off the northern CA coast. The low is expected to lift north, amplifying the anticyclone and shifting the center a little further north and east through the week. This will enhance the undercutting easterly flow across Southwest. EPS/GEFS/CMC resolve this, with H5 heights anomalously higher over the Pacific Northwest, indicating an even broader easterly flow is likely by this weekend. Until then, PoPs remain elevated with continued chances of showers and thunderstorms each day across the entire CWA. Several EPS and GEFS members latch onto a significant wave moving through the Southwest around Saturday (give or take a day for uncertainty). The EPS-based EFI QPF data has an interesting signal in that the majority of members are not forecasting climatologically high rainfall, but there are a small minority of members that are predicting QPF outside the model climate for August. This aligns with an axis of enhanced instability and moisture emanating north out of the Gulf of California and arcing NNE into southern Idaho. Digging a little deeper through cluster analysis of the global ensembles, the details of this will really depend on the evolution of the upper level low to our northwest. A deeper solution (favored by 1/3 EPS and 1/2 CMC but just one GEFS members) would increase wind fields and moisture flux resulting in greater precip potential. Even the NBM is indicating non-zero chances for 24-hr QPF of 1"+. Given the increased cloudiness and moisture through the forecast period, high temperatures will likely (~80%) remain below daily normals. Temperature variability is quiet high, especially around the weekend with the potential influx of even higher moisture and clouds (NBM IQR for Sunday`s high temperature is 96-105F). HeatRisk levels will remain in the Moderate category across SE CA through the week with Low expected across most of Arizona - thus some heat impacts are possible especially for those with greater exposure or those exerting themselves outdoors. With many schools going back in session, it`s worth reminding kids (and teachers/faculty) to pace themselves and hydrate appropriately. && .AVIATION...Updated 0029Z. South-Central Arizona including KPHX, KIWA, KSDL, and KDVT: Storms to the north, east, and south of the Phoenix over southeast and eastern AZ have been isolated with newer development over southwest Maricopa County. Outflow that had been approaching from Pima County has weakened. Given the lack of more robust activity, and convective inhibition evident in aircraft sounding data, have removed the mention of VCTS from the TAFs. However, storms over southwest/west Maricopa County could produce outflow that potentially reach the the TAF sites. As has been seen a number of times this Monsoon season, late night shower and thunderstorm activity will be possible, but would expect it to be weaker than last night and more isolated (if it happens at all). Apart from outflows, light west and northwest winds will prevail before trending toward light easterly late tonight. As for sky cover, expect increasing mid and high clouds as the night progresses followed by thinning during the day Wednesday. Southeast California/Southwest Arizona including KIPL and KBLH: KIPL: Thunderstorms are ongoing in the vicinity of KIPL with gusts of 30-35 kts and blowing dust dropping visibility below 6SM. Anticipate erratic winds and at least one downpour reducing vis to between 2SM - 4SM along with ceilings to between FL070-090. Anticipate significant decline in storm activity to begin by 02Z. Winds will become lighter as well with variable directions before southeasterly resumes overnight. There is potential for another round of activity tomorrow afternoon. KBLH: Earlier storm activity has likely helped stabilize things over/near KBLH to preclude new storm development the rest of the afternoon and evening. A round of late night/morning showers is possible but confidence of those occurring at the airfield too low to reflect in the TAF. Anticipate light and variable winds to become southerly overnight and continue through the day Wednesday. As for sky cover, anticipate variable amounts of mid and high clouds with bases AOA FL120. && .FIRE WEATHER... A humid airmass will remain in place through the forecast period, yielding elevated afternoon RH values and good overnight recovery. Chances for wetting rains will continue for most areas almost daily. Winds for the most part will remain light, with the exception of thunderstorm outflows generating stronger gusts. The fire danger threat is expected to remain low for the foreseeable future. && .PSR WATCHES/WARNINGS/ADVISORIES... AZ...Flood Watch until 2 AM MST Wednesday for AZZ530>544-546-548>551- 553>555-559. Flood Watch until midnight MST tonight for AZZ545-547-552- 556>558-560>563. CA...Flood Watch until 2 AM PDT Wednesday for CAZ560>570. && $$ DISCUSSION...Sawtelle/Iniguez AVIATION...AJ FIRE WEATHER...Iniguez
National Weather Service Raleigh NC
950 PM EDT Tue Aug 9 2022 .SYNOPSIS... High pressure centered near Bermuda will extend westward across the Southeast states through early Wednesday. A cold front will approach from the northwest late Wednesday, then move slowly southeast through North Carolina Wednesday night through Thursday night. A secondary cold front will drop through the region late Friday. A cooler and less humid air mass will build in from the north for the weekend. && .NEAR TERM /THROUGH TONIGHT/... As of 950 PM Tuesday... Strong slow moving thunderstorms produced pockets of 1 to 3 inches of rainfall over the Triad, northern Sandhills, and the southern Piedmont and have left a myriad of outflow boundaries across central NC. One of which is draped over the Sandhills and is acting to focus some shower/storm activity within a pocket of MLCAPE around 2000 J/kg and very little MLCIN which has avoided any convective contamination so far this evening. RAP forecast and mesoanalysis trends suggest deep moisture convergence over this area will slowly weaken and increasing boundary layer stability will effectively cut off precipitation chances within the next couple hours. As for temperatures, persistence will rule the forecast as low-level thicknesses will be comparable to the previous couple of mornings; leading to lows in the upper 60s to low/mid 70s with urban areas expected to remain the warmest. && .SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/... As of 251 PM Tuesday... A broad upper-level trough centered across eastern Canada will begin to dig southward into the Great Lakes region on Wednesday. Ahead of the trough, a short-wave will extend down into central NC Wednesday afternoon/evening. Associated weak mid-level height falls and transiting vorticity perturbations will provide better upper-level support for higher coverage in afternoon showers/storms compared to recent days. High-res models continue to depict mountain convection spilling eastward into western portions of our area early afternoon supportive of likely POPs across our far northwest. Additional convection will also focus along the Piedmont trough initially over the Sandhills/Central Piedmont, and spread eastward through Wednesday night. PWAT will be high again peaking near 2.0 inches, supporting high CAPE ahead of the convection. However, models continue to depict weak mid-level lapse rates and shear, which should limit organization. Regardless, given some better upper- support trickling in from the north, organized clusters may be possible as the convection pushes east. Thus, isolated damaging wind gusts could materialize within any stronger cells, but widespread severe weather is not expected. Lastly, given the high PWAT and slower storm motion, isolated flash flooding may be possible in or near urban areas tomorrow afternoon/evening (especially across the Triad where the WPC currently maintains a marginal risk for flash flooding (level 1 of 4)). Otherwise, daytime highs will once again peak in the lower to mid 90s, with overnight lows remaining warm in the lower to mid 70s. && .LONG TERM /THURSDAY THROUGH TUESDAY/... As of 120 PM Tuesday... Low pressure off the VA coast will drag a cold front across the area on Thursday. Pre-frontal airmass characterized by PW`s around 1.75 inches, surface dewpoints in the 70s, and MLCAPEs around 500-1000 J/KG, will still be present across the area on Thursday, and showers and thunderstorms should develop during the afternoon hours with a focus mainly across the southern half of the forecast area. Guidance pops still lingering in the 60-80 percent range during this period and the updated forecast will remain near these values. While the presence of a clearly defined forcing mechanism should result in organized thunderstorm development, the lack of deep layer shear (only 10-15kts) and extensive cloud cover should temper the severe threat a bit. Friday will see a secondary boundary cross the area from the northwest, this one ushering in lower dewpoints and a clear trend toward dry weather. By Friday afternoon, most locations should see dewpoints in the upper 50s to lower 60s, the only exception being across the southern Coastal Plain where the boundary may stall and serve as the focus for a few showers and thunderstorms. Surface ridging over the Ohio Valley should strengthen Friday night into Saturday, move eastward into the Mid Atlantic, and effectively push the front into SC on Saturday resulting in drier weather for the weekend. Temperatures will still manage to rise into the lower 80s (north) to upper 80s (south) but it will be noticeably more comfortable this weekend. Similarly, low temps will also fall below climatological normals with readings in the upper 50s (north) to mid 60s (south). Broad northwesterly flow aloft will persist into early next week, with a series of weak perturbations potentially moving across the mountains into NC Monday and Tuesday. Varying ensemble solutions aloft with some solutions indicating an upper low over the Great Lakes while others bring a deeper low through the Tennesse Valley. Cluster analysis tends to discount the TN low solution with odds tilted more in favor of continued northwesterly flow and an upper low over eastern Canada. This would result in a return to typical summer weather with daily shower/storm chances within a Piedmont trough propagating off the mountains and into central NC. PoPs in the 20-30 percent range are consistent with today`s ensemble runs as well as the latest NBM. Temps will increase a bit during this period but still remain at or slightly below normal. && .AVIATION /00Z WEDNESDAY THROUGH SUNDAY/... As of 804 PM Tuesday... Convection is quickly fading/dissipating, with only some isolated showers lingering across central NC. Remainder of the night will be dry with predominately VFR conditions expected. The exception could be some scattered/briefly broken MVFR ceilings INVOF KINT and KGSO towards daybreak. The approach of an upper trough and attendant lead surface cold front from the NW will lead to higher coverage in showers and storms compared to recent days. Periods of IFR to MVFr restrictions will be possible with the stronger storms. Light southwest winds of 5 to 10kts are expected through the TAF period, with the potential for some occasional gustiness into the teens at KRDU, KRWI, and KFAY Wednesday afternoon. Outlook: Showers and storm chances increase again on Thursday/Thursday night as a cold front pushes through the area. Drier conditions are then expected Friday through Sunday. && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Hartfield NEAR TERM...Swiggett SHORT TERM...Luchetti LONG TERM...Leins AVIATION...CBL/Luchetti
Area Forecast Discussion
National Weather Service Springfield MO
607 PM CDT Tue Aug 9 2022 ...Updated 00Z Aviation Discussion... Key Messages: 1. A isolated showers/storms remain possible tonight and early tomorrow as a front over southern MO moves slowly south into AR and stalls/weakens. Widespread rain isn`t expected, but still could see isolated downpours. 2. May see some fog potential tonight with low level moisture and a cooling boundary layer. Will monitor trends for possible fog advisory late tonight. 3. Fairly quiet weather is then expect through the weekend with a Canadian surface high center moving into the Great Lakes Friday- Saturday. Temperatures will turn hotter again over the weekend but with lower humidity. .SHORT TERM...(This evening through Wednesday) Issued at 300 PM CDT Tue Aug 9 2022 A weak frontal boundary dropped south to the vicinity of the Missouri and Arkansas state line this afternoon. A few slow moving showers/thunderstorms are still festering over south central MO closer to a subtle upper level vort/low that shows up in midlevel water vapor imagery. HRRR and some other short term high res guidance show better chances for scattered convection over our eastern counties into the evening hours. Progged soundings show modest instability but still fairly robust pwats close to 2.00 inches (from some guidance). Will need to watch for isolated slow moving pulse storms and localized flooding. Will start to see higher clouds clear from the northwest later this evening setting up some fog potential with weak low level winds and (finally) some soil moisture. Guidance varies on the amount of overall clearing so will need to monitor trends. Better chances would seem to be over the northern and eventually western cwfa. The weak sfc front will stall south of the area Wednesday. Some lingering precip may be possible early in the day, but by afternoon, progged showers look to push south of the southern MO border. Clouds may linger, especially over our eastern counties. Overall, it looks like a quiet, fairly pleasant day with highs in the 80s, possibly touching 90 over the far western cwfa. .LONG TERM...(Thursday through Tuesday) Issued at 330 PM CDT Tue Aug 9 2022 Thursday: An upper ridge over the western U.S./Rockies will edge east a bit as the upper low trough over southeast MO shifts east. Midlevel height rises and a mostly clear sky are expected for Thursday with a weak sfc ridge edging into the Midwest. Friday-Monday: The upper flow pattern will remain little changed with the western upper ridge moving east somewhat into the High Plains. A sfc ridge will extend from high pressure over the Great Lakes to the Ozarks pushing a comfortable air mass into the area with lower dew points. A weak sfc low/trough will approach the area late in the weekend veering winds a bit to the southwest with temperatures likely to bump up well into the 90s over the western cwfa, possibly touching 100F again over southeast KS and KJLN area Sunday and Monday. Tuesday: Consensus guidance breaks down the ridge somewhat by Tuesday, but not confident to what degree. A signal for increased chances for precip does exist by late Tuesday/Tuesday night into the midweek period as the upper ridge retrogrades or becomes established farther back to the west and impulses move southeast through the region in northwest flow aloft. This would point to cooler weather with some chances for showers/storms during the midweek period. ECMWF ensemble members show a period of cooler than normal temperatures by late next week. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 607 PM CDT Tue Aug 9 2022 VFR conditions are expected for most of the TAF period, outside of a low end chance for an isolated shower through the overnight hours. Winds will remain light and variable through tonight. Continuing to monitor fog potential across parts of the area overnight. At this time, confidence remains too low to mention in TAFs. An isolated shower or thunderstorm remains possible at KBBG on Wednesday morning, but coverage remains limited at this time. Otherwise, a dry and quiet day can be expected. && .SGF WATCHES/WARNINGS/ADVISORIES... MO...NONE. KS...NONE. && $$ SHORT TERM...DSA LONG TERM...DSA AVIATION...Perez
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
740 PM EDT Tue Aug 9 2022 ...New UPDATE, AVIATION... .UPDATE... Issued at 737 PM EDT Tue Aug 9 2022 Conditions have stabilized across West Central and SWFL after earlier convection pushed through. Florida remains in the vicinity of an inverted trough axis, which has continued to destabilize and cool the mid-levels of the atmosphere, aiding vertical ascent slightly and providing a boost to afternoon convection. Could this perhaps allow a few more storms to develop late this evening? It could. Some high-res guidance such as the HRRR continues to hint at this possibility. The probability is rather low, though, with so many factors to limit additional convection. A few tweaks to the POPs have been made through the evening to better account for current trends. Winds have also been tweaked slightly to better capture conditions. Otherwise, the forecast remains on track. Things are definitely looking much drier for the next few days with more dust advecting over the state, greatly suppressing thunderstorm development. No further significant changes are anticipated before the overnight updates. && .DISCUSSION... Issued at 405 PM EDT Tue Aug 9 2022 Surface high pressure ridge axis will remain north of Florida through Wednesday then gets pushed south into the area Thursday and then into the Florida Straits by the weekend as an upper level trough and associated cold front move through the southeast states. The east to southeast low level flow will continue through Wednesday then become rather light Thursday and Friday, and then north to northwest this weekend. For the rest of today we`ll see scattered showers and thunderstorms continue to move quickly northwest across the area into early this evening. Skies will then become partly cloudy later this evening and overnight. Later tonight into Wednesday the dry Saharan Air Layer (SAL) will move in from the southeast with precipitable water values still forecast to fall below 1.5 inches across much of the area. This will delay the convection until mid to late afternoon and evening and also limit the overall coverage with rain chances 30 percent or less. Highest chances should be along the west coast late in the day where the sea breeze will be located. For Thursday a rather light southeast to south flow will be in place as the ridge axis shifts south across the area with the dry SAL holding on for much of the day. Should see the sea breezes develop and move well inland thanks to the rather light flow and this along with the limited moisture could pop a few showers and thunderstorms, but overall chances will remain 30 percent or less. On Friday the weakening frontal boundary will move into north Florida suppressing/splitting the ridge axis and thus allowing winds to become light and variable. Deep moisture in the vicinity of the boundary will drift south into the northern parts of the area, but with the flow being rather light the highest rain chances will be over the northern Nature Coast and interior. On Saturday the low level west to northwest flow will setup and with plenty of moisture in place we`ll see scattered to numerous showers and thunderstorms develop with the best chances across the Nature Coast and interior. However, with the flow being westerly and the frontal boundary stalled out to the north we could see convection at almost anytime across the Nature Coast, while further south it will be mainly during the afternoon and evening hours. Early next week the upper level trough will remain over the eastern U.S. with abundant moisture across the area leading to scattered to numerous convection. Main hazards from the thunderstorms through the forecast period will continue to be strong gusty winds, frequent lightning, and locally heavy rainfall that could cause flooding of low lying and poor drainage areas. Also, with the 500 mb temperatures remaining around -7C to -8C over the next few days some hail cannot be ruled out in the stronger storms. && .AVIATION... (00Z TAFS) Issued at 737 PM EDT Tue Aug 9 2022 Conditions have become quiet at area terminals with the atmosphere now stabilizing after earlier storms. Some high-res models hint at a few more storms overnight, but the probability is too low for mention at this time, given how stable the atmosphere has become. A similar story for tomorrow afternoon as well. While a couple isolated storms could form in the 20-00Z time-frame, any impacts to terminals are far too low for mention at this time. What is more favorable is a few low clouds at terminals in the 10-14Z time-frame with light ESE flow and cooler temps from earlier rain. && .MARINE... Issued at 405 PM EDT Tue Aug 9 2022 High pressure ridge axis will remain north of the area through midweek producing moderate east to southeast wind flow over the coastal waters with occasional nocturnal surges for increased seas at times. Scattered showers and thunderstorms are expected mainly during the late afternoon and nighttime hours with gusty outflow winds and dangerous lightning, along with locally higher winds and seas. High pressure sinks southward into the region later in the week with lower winds and seas expected, but scattered showers and thunderstorms will continue. && .FIRE WEATHER... Issued at 405 PM EDT Tue Aug 9 2022 No fire weather hazards are expected through the week as minimum relative humidity values will remain above critical levels and winds will remain less than 15 mph outside of any convection. && .PRELIMINARY POINT TEMPS/POPS... TPA 95 79 95 80 / 80 20 30 20 FMY 94 77 95 78 / 80 20 30 10 GIF 96 76 96 77 / 80 20 20 10 SRQ 93 75 93 77 / 80 20 30 10 BKV 94 74 95 74 / 70 20 20 20 SPG 93 79 93 81 / 80 20 30 20 && .TBW WATCHES/WARNINGS/ADVISORIES... FL...None. Gulf waters...None. && $$ UPDATE...Flannery/Close AVIATION...Flannery PREVIOUS DISCUSSION/MARINE/FIRE WEATHER...Close
Area Forecast Discussion
National Weather Service Tulsa OK
933 PM CDT Tue Aug 9 2022 ...New SHORT TERM... .SHORT TERM... (The rest of tonight) Issued at 928 PM CDT Tue Aug 9 2022 Eastern OK and western AR largely sandwiched in between two areas of convection this evening. One cluster over central OK, with severe warned cell in Lincoln/Creek Co. Another larger cluster focused over NC/NE AR. These occurring within old frontal zone/moist axis and with modest low level jet developing tonight, expect isolated to scattered showers and storms to eventually fill in over about the southern 3/4 of the CWA overnight as suggested by last several HRRR runs. Aside from some minor changes to POP grids early in the period, remaining forecast in good shape. && .LONG TERM... (Tonight through Tuesday) Issued at 111 PM CDT Tue Aug 9 2022 Modest low level jet will develop tonight with scattered storms possible into Wednesday morning. Main precip area on Wednesday will begin to focus further south as drier air begins to filter into the region from the northeast. Upper high currently over the Four Corners Region will begin to shift east closer to the area with warm/humid conditions likely through the weekend. High temperatures will again approach triple digits early next week with excessive heat becoming more of a concern. Overall rain chances through the extended periods will likely remain low, however isolated storms possible Friday afternoon across far southeast Oklahoma and across northwest Arkansas by Tuesday of next week. && .AVIATION... (00Z TAFS) Issued at 609 PM CDT Tue Aug 9 2022 VFR conditions likely to persist into the early morning with very low chance of any convective development this evening. Thereafter isolated to scattered early morning convection appears possible. Also patchy fog may develop across NW AR before sunrise. Overall the coverage of showers and storms should be lesser tomorrow with VFR conditions largely prevailing. && .PRELIMINARY POINT TEMPS/POPS... TUL 73 93 69 93 / 20 10 0 0 FSM 74 92 74 94 / 50 40 10 20 MLC 72 93 71 93 / 30 20 10 10 BVO 70 93 65 94 / 10 0 0 0 FYV 69 89 65 90 / 40 30 10 10 BYV 70 87 66 90 / 40 30 10 10 MKO 71 89 70 91 / 30 20 0 10 MIO 70 91 64 93 / 20 10 0 0 F10 71 92 69 93 / 30 10 0 10 HHW 72 92 71 92 / 40 40 20 20 && .TSA WATCHES/WARNINGS/ADVISORIES... OK...None. AR...None. && $$ SHORT TERM...14 LONG TERM....12 AVIATION...07