Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/21/22

Area Forecast Discussion
National Weather Service Burlington VT
1027 PM EDT Wed Jul 20 2022 .SYNOPSIS... A few strong thunderstorms will be possible this afternoon across northern and central Vermont before diminishing this evening. Another hot and humid day is on tap Thursday with heat indices once again around 95 degrees. In addition, strong to severe thunderstorms will be possible Thursday afternoon from the Champlain Valley eastward. These storms will weaken and exit the region on Thursday with quieter and slightly cooler weather on Friday. && .NEAR TERM /THROUGH THURSDAY NIGHT/... As of 1018 PM EDT Wednesday...A very warm and muggy night prevails acrs the fa, with BTV crntly 84F over 69F as of 10 PM. Did tweak pops acrs northern NY thru early Thurs, mainly to lower values slightly below likely thru 12z, before expanding quickly by 14z. Still a few rumbles overnight are possible, as instability lingering overnight with warm temps and high dwpts. Did a quick review of 00z data coming into the office this evening and many parameters still look favorable for severe storms. CAPE values should be in the 2000-2800 J/kg, with deep layer shear of 35 to 40 knots with good height falls as mid/upper lvl trof swings to our northwest. CAMs still have some uncertainty on areal coverage and potential storm mode, but given mainly unidirectional shear and associated straight hodographs, thinking multiple cell clusters, evolving into bowing line segments look likely. Mainly threat continues to be damaging winds with hail and a potential quick spin up as secondary threats. Convection should start firing btwn 10 and 11 AM acrs northern NY and quickly build and expand in areal coverage/intensity as it encounters better storm relative inflow associated with south winds 15 to 25 knots by noon or so acrs the CPV. Otherwise, another warm and humid day on tap with highs well into the 80s and locally near 90F parts of the CPV and lower CT River Valley. Previous discussion follows: The upper level ridge axis appears to have settled across the Adirondacks this afternoon and hasn`t quite pushed into Vermont. This is evident in the recent radar images showing convection firing across northern New York and moving into Vermont. The air mass across Vermont is very unstable with recent LAPS and RAP data showing upwards to 3000 J/kg of CAPE with 20-30 knots of effective bulk shear. At this point, it doesn`t seem like there will be any limiting factors to these storms continuing and likely intensifying over the next few hours as there really isn`t anything to inhibit thunderstorm develop. Ultimately, the upper level ridge will continue to slide eastward as surface instability begins to wane around sunset and should put a quick lid on these storms. Quiet weather overall is expected to continue through much of the evening and overnight hours as the upper level ridge axis moves overhead but it`ll be warm and humid with many places only seeing low temperatures fall into the upper 60s to mid 70s. Another very hot and humid day is on tap for Thursday. Given that temps will struggle to fall during the overnight period tonight, it won`t take long to see temperatures warm into the upper 80s to lower 90s across much of the region. The one fly in the ointment, and it`s a big one, is at point does the convection associated with a prefrontal trough develop across the western Champlain Valley in New York. The latest guidance has sped up the arrival of a prefrontal trough into the Champlain Valley around 11 AM or noon which could potentially bring a quicker increase in cloud cover and rain cooled air which would significantly limit heating. Anyways, back to the thunderstorm potential. A prefrontal trough is expected to interact with an airmass with attributes including 1500-2500 J/kg of CAPE, 30- 40 knots of effective bulk shear, and height falls aloft allowing for good vertical velocities. The latest HREF from SPC shows strong updraft velocities across the region during the afternoon hours which would suggest strong to severe thunderstorms developing ahead and along the prefrontal trough. Another round of showers and thunderstorms is appearing increasingly likely during the mid to late afternoon hours as a cold front begins to move through the North Country. While the front is likely to interact with a rain cooled air mass, the mid-level temperatures will also be trending downwards. This will yield slightly lower CAPE values closer to 1000 to 1500 J/kg but shear will still be impressive and DCAPE values close to 1000 J/kg are expected to persist. Given the early start to the convection, it looks like by 8 PM the bulk of the showers and thunderstorms will have either dissipated or exited to our east which will bring an end to severe potential on Thursday. Thursday night looks rather uneventful with decreasing PoPs and some clearing skies. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 326 PM EDT Wednesday...The overall weather pattern that will set up starting Friday and drive the weather through the weekend will be driven by another upper low that will anchor in place near southern Hudson Bay. We`ll remain on the southern periphery of the low but within the track of multiple shortwaves moving through the fast zonal flow. Friday looks like the best chances for dry weather for most of the area despite the shortwaves transversing the region. The air mass will be quite a bit drier on Friday than the previous few days, and building surface ridging should suppress the development of precipitation during the day. It will be another toasty day however, with highs forecast in the low to upper 80s for most of the area. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... As of 326 PM EDT Wednesday...For Saturday, we`ll see better chances for a few afternoon showers with increasingly zonal flow and some weak shortwaves moving through. Saturday will be the warmest day of the weekend, with many areas seeing afternoon highs in the mid 80s to low 90s. Dewpoints in the low to mid 60s will make for another warm and muggy mid- summer day. Any showers that do develop will have a good chance of developing into thunderstorms given the amount of instability present, though coverage is not expected to be widespread. Saturday night, a moisture boundary will move through and precipitable water values will climb to around 1.75 inches. The influx of moisture in combination with warm overnight temperatures will setup an unstable environment by Sunday morning, with models showing between 500 and 1500 J/kg CAPE by midday Sunday. As the back end of the moisture/frontal boundary moves through during the day, expect a line of showers and thunderstorms to develop. Highest thunderstorm potential for Sunday will be over southern and central Vermont where the boundary will move through the latest and temperatures will climb into the upper 80s in valley locations. An earlier frontal passage for northern NY and northern VT will keep conditions a good 10 to 15 degrees cooler than areas further south. From Monday onwards, we`ll see a pattern shift with the arrival of a drier and cooler air mass from the northwest wrapping around high pressure over the Great Lakes Region. Temperatures to begin next work week will top out in the mid 70s to mid 80s each day, with a gradual warming trend going into mid-week. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Through 00Z Friday...Currently VFR, with light rain showers moving across KMSS. Winds are trending southerly, and will remain steady near 5 knots and then begin to gradually increase after 06Z. Winds aloft will be increasing a bit more quickly, especially over northern New York, and noted some LLWS at KMSS and KSLK through about 09Z. After 09Z, winds should increase to 9 to 14 knots with gusts 16 to 24 knots, though a bit longer to reach these speeds at KEFK and KMPV. Showers and an isolated thunderstorm will approach KMSS and KSLK about 09Z to 11Z, and move east into Vermont about 15Z to 17Z. Additional storms will develop near or east of KSLK about 19Z to 22Z, moving east of the region about 00Z Friday. With any of these rounds, there could be a few storms capable of strong, gusty winds, frequent lightning, and heavy rain that reduces visibility. At this time, it seems storms will not merge into clusters or lines, but this possibility is not out of the question. So most terminals have a mention of VCTS, but have included in a tempo for KEFK, KMPV, and KRUT where the chances will be highest, but the activity could be hit or miss. As the front shifts east, winds become southwesterly, remaining about 6 to 10 knots into 00Z Friday. Outlook... Wednesday: VFR. NO SIG WX. Wednesday Night: VFR. Chance SHRA, Chance TSRA. Thursday: VFR. Likely SHRA, Chance TSRA. Thursday Night: VFR. Slight chance SHRA. Friday: VFR. Slight chance SHRA, Slight chance TSRA. Friday Night: VFR. Slight chance SHRA, Slight chance TSRA. Saturday: VFR. Slight chance SHRA, Slight chance TSRA. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Clay NEAR TERM...Clay/Taber SHORT TERM...Duell LONG TERM...Duell AVIATION...Haynes
Area Forecast Discussion
National Weather Service Columbia SC
1000 PM EDT Wed Jul 20 2022 .SYNOPSIS... Typical summer pattern with seasonable temperatures and mainly diurnal showers and thunderstorms through Thursday. A front will be near the area late Thursday bringing higher chances of widespread thunderstorms that may produce damaging wind gusts north and west. Warmer and slightly drier this weekend into early next week. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... The main upper trough has pushed through and the axis has moved over the coast. Surface winds continue to be from the south/southwest and moisture transport remains high over the forecast area. Mighty moist environment with PWATs over 2 inches and dewpoints in the upper 70s. Both DCAPE and MUCAPE have decreased significantly over the past hour and the isolated thunderstorms within the CWA have dissipated. Later tonight, a weak upper impulse is expected to shift over the area but confidence in timing and extent is still a bit uncertain. Looking at MRMS there are several showers moving down from the Upstate of SC and northern GA and will near the area overnight. These will likely dissipate by the time they near our CWA. Past that, some of the most recent CAMs show the boundary currently in Kentucky and Tennessee traveling south and bringing down better organized storms near daybreak. Have kept chance/slight chance PoPs overnight as timing remains the biggest uncertainty. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/... General upper troughing remains over the area Thursday with some HiRes models indicating lingering convection into the morning, similar to what was observed today. It does appear, however, that the axis of the upper trough should shift farther to the east which may keep any morning convection in the Coastal Plain. The evolution of morning showers or storms will be important to how things play out into the afternoon as a cold front drops into the southern Appalachians. While the front likely remains NW of the forecast area, storms will develop along it and move southeast into the forecast area. HREF mean shows moderate to strong destabilization across the forecast area by the afternoon into the evening. While deep layer shear will be fairly weak, 850mb winds will increase to around 20 to 30kts. As PWATs increase to around 2.25 inches, precip loading and increased low level winds will support a damaging wind gust threat, especially across the northern and western portion of the forecast area, where SPC has outlined the area in a slight risk. The timing for the highest chance of severe weather appears to be tomorrow evening. Any storms that move into the area will likely encounter the sea breeze as well which would help to enhance convergence over the forecast area. With PWATs above 2 inches, there will be a bit of a flooding threat, although the general steering flow should be strong enough to limit flash flooding outside of any training storms. The area to watch would be where the sea breeze and storms coming from the NW meet, especially if this occurs over an urban corridor. Temperatures will generally be seasonably hot tomorrow with SW winds reinforcing the warm, moist airmass. Heat indices as a result will generally max out around 105 for most of the area. Overnight lows in the low to mid 70s. Friday, lingering boundaries will be in the area and the airmass remains moist. Convection will likely be a bit more scattered with less forcing compared to Thursday. Highest chance of showers and storms will be in the southeast area in an area of convergence along a lingering boundary and the sea breeze. A few degrees cooler with increased clouds across the area and at least a chance of lingering showers in the morning. Still, highs will be in the low 90s with dew points remaining in the 70s will make Friday feel fairly similar. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... Upper level ridging will be building over the area in the long term period. NAEFS indicate that heights will be above the 90th percentile with a strengthening of the Bermuda High off the coast. This will support temperatures continuing to be a few degrees above average with south-southwesterly flow keeping dew points generally in the 70s through the period. Ensemble suites generally support the pattern remaining fairly persistent through early next week with a weakening of the ridge by midweek as an upper trough amplifies towards the end of the period. Majority of ensemble members show moderate destabilization each day with PWAT values around average. With a lack of a significant trigger, this supports a general summertime pattern with isolated to widely scattered thunderstorms each afternoon and slightly above average temperatures. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Generally VFR conditions are expected through the evening and overnight hours although some morning stratus cannot be ruled out. Isolated to scattered storms are around the area this evening but none immediately impacting any terminals so will leave out at this time and amend as needed. Upper trough axis will shift east of the area tonight and some lingering showers may be present through the predawn hours but again confidence is low in impacts to terminals. HRRR and SREF hinting at possible morning stratus so included a tempo group from 10z-14z as confidence is a bit low. Do not expect fog to be an issue with winds staying up overnight and a 20 knot low level jet. Relatively high chances of convection tomorrow with some strong to severe storms possible with strong wind gusts in excess of 40 knots and heavy rain could reduce vsbys at times. Included a mention of thunder after 18z. Winds on Thursday should pick up to around 10 knots with gusts up to 20 knots outside of thunderstorms. EXTENDED AVIATION OUTLOOK...Scattered mainly afternoon and evening thunderstorms Thursday, and possibly again Friday but favoring southern areas, along with some possibility of patchy late night/early morning fog/stratus. Drier over the weekend with a lower chance of restrictions. && .CAE WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. && $$
Area Forecast Discussion
National Weather Service Dodge City KS
545 PM CDT Wed Jul 20 2022 ...UPDATE TO AVIATION... .SHORT TERM...(This evening through Thursday) Issued at 352 PM CDT Wed Jul 20 2022 Mid/high level cloud, a few scattered showers, and a northeast wind kept temperatures at bay as compared to the past several days...especially yesterday. A small mesoscale convective vorticity (MCV) max was located across the eastern Panhandles with influence northward toward our southern counties from Liberal to Englewood. Small showers will continue in this region through late afternoon, and there may be a couple lightning strikes, but the atmosphere is quite stable to deep, moist convection. Tonight, a larger MCS will develop and track east-southeast across eastern Colorado. This MCS will make a run at our far western counties later this evening, likely after 02Z (9 PM CDT), and will also be in a weakening phase as it makes its way into far southwest Kansas. Thus, we will be keeping 20-30 POPs only right up against the Colorado border. The HRRR shows quite a bit of outflow wind with its modeled MCS, so the evening crew will need to monitor this potential wind threat later in the evening across our far southwest. Another MCV will likely remain after the MCS dies to our south, and this may reinvigorate showers/isolated thunder across our far southern counties -- the same general region where the showers were occurring this afternoon. Later Thursday afternoon, additional isolated to widely scattered showers/storms may develop, but the anticipated coverage does not look all that great given absence of appreciable low level convergence. We will keep POPs below the mentionable 15 percent for much of the area, as a result. As far as temperatures are concerned, we will likely see an uptick in afternoon temperature by a couple degrees over this afternoon`s temperature, but this is based on a mostly sunny sky much of the day. There may be enough mid/high cloud to keep temperatures in check across the southern portion of the forecast area (south of the Arkansas River). .LONG TERM...(Thursday night through Wednesday) Issued at 352 PM CDT Wed Jul 20 2022 The trend toward a return to 100+ heat is still on track. Saturday and Sunday still look like the hottest days in the Long Term ahead of the next cold front. Increased model agreement on Saturday afternoon`s temperature resulted in a bump up in the NBM MaxT, with a larger area of 106-107F in the grids now for Saturday`s high. It will not be too surprising to see a couple 108 to even 110F if the thermal ridge is as pronounced as the latest model runs have it across west central/northwest Kansas. As mentioned in previous discussions, Sunday`s forecast is a bit more difficult based on the timing of the front. locations just out ahead of the front on Sunday will almost assuredly exceed 106F. The ECMWF, Canadian GDPS, and GFS models all differ on the front placement after Sunday. The ECMWF model is more ambitious about the front pushing through southwest Kansas on Monday providing another break from the heat...although for only a day. The ECMWF builds the heat back north into southwest/west central Kansas on Tuesday. The global deterministic models continue to show a favorable signal of the polar front pushing all the way through by Wednesday Night or Thursday of next week, but this is 6-7 days away, and a lot will likely change in this forecast. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 543 PM CDT Wed Jul 20 2022 VFR conditions will prevail in vicinity of all TAF sites through early Thursday afternoon. South-southeasterly winds around 5 to 15kt are expected to continue through early Thursday as surface high pressure slides southeast across eastern Kansas during the period. && .PRELIMINARY POINT TEMPS/POPS... DDC 71 100 70 102 / 10 10 10 10 GCK 69 97 67 102 / 10 10 10 10 EHA 71 95 68 99 / 40 20 10 10 LBL 71 98 68 101 / 20 20 10 0 HYS 69 100 71 103 / 10 10 10 10 P28 73 102 72 102 / 10 10 10 10 && .DDC WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SHORT TERM...Umscheid LONG TERM...Umscheid AVIATION...JJohnson
Area Forecast Discussion
National Weather Service Grand Rapids MI
913 PM EDT Wed Jul 20 2022 LATEST UPDATE... Update .UPDATE... Issued at 913 PM EDT Wed Jul 20 2022 We have a narrow band of convection (no thunderstorms at this point) moving over the Muskegon area at 9 pm this evening. There is between 500 and 800 j/kg of MU cape to work with and it is on the right front exit region of jet core over WI. I expect this will hold together for the next few hours it is forced by mid level dynamics and not surface based heating. The showers will mostly stay near and west of US-131. The showers at any one place will last less than 30 minutes but some will bring brief heavy rainfall rates even without thunder. Skies should clear after midnight. UPDATE Issued at 631 PM EDT Wed Jul 20 2022 I took the thunder out of the evening forecast since looking at model sounding and also looking at the RAP model mixed layer cape for the this evening there is not enough instability for the showers moving into our area this evening from WI to become thunderstorms (they are not thunderstorms now either). Also I added 20 to 30% pops to our forecast Thursday evening as there is a shortwave moving through our southern CWA. We are in the left exit region of the jet core and we have warm advection at low levels we cold advection at high levels. The MU cape increase to near 1000 j/kg south of I-96 during Thursday evening as that shortwave moves through. Both the HREF and SREF 06 hour probability of 0.01" is between 20 and 40 percent south of I-96 then too. This will not be a big event but there will be scattered showers moving through the area. I adjusted the cloud forecast to match the precipitation forecast so that would make sense. As a side note, I do expect to end the small craft advisory and beach hazards as per there forecast expiration since looking at we beach cams and some buoy data, conditions continue to improve. && .DISCUSSION...(This evening through next Wednesday) Issued at 305 PM EDT Wed Jul 20 2022 ...A Few Showers/Storms This Evening... Mid level height falls continue this evening as the closed low over tracks eastward through the northern Great Lakes Region. Relatively deep cyclonic flow will persist over portions of the CWA this evening leading to some upward forcing. MU CAPE values from the latest HRRR are pointing to instability persisting this evening with especially closer to the lakeshore. We will maintain a low risk for showers and storms this evening...mainly for the western half of the CWA A narrow line of relatively shallow convection has developed from near Lansing to Battle Creek. This line was tracking east and should push east of Jackson by 430 pm. Surface dewpoints have already dropped off into the 60s. ...Gusty winds diminishing late this afternoon into the evening... Based off of the KGRR VWP fairly deep 30 to 40 knot winds exists within the mixing layer. Surface values have generally been in the 30 to 35 knot range with a few briefly higher gusts recorded. Scattered power outages have been ongoing all afternoon. As the mixing height drops off later this afternoon into the will the surface gusts. ...Still looking at a higher potential for showers/storms Saturday night into Sunday... A stronger upper level jet in zonal flow is shown to push eastward through the Upper Plains Saturday evening into the night. Meanwhile a low level jet will be nosing into the WI/Northern IL region...advecting in abundant moisture. With favorable instability in appears an MCS will get going. Based on the projected movement of this feature...the CWA could see a round of showers/storms through the night. There is still some uncertainty on this...but the models have been showing this for several runs. We will maintain higher POPs for this potential event. ...Another round of storms possible Wednesday... There is some general agreement in the models in showing a cold front tracking through the CWA on Wednesday. The atmosphere is shown to moist and unstable ahead of this feature with a deep southwest flow out ahead of the front stretching down into the Gulf. Relatively fast flow is shown to exist in the mid levels...which leads to decent deep layer shear. We will feature a risk for storms in this period and will need to monitor the severe risk as we near this timeframe. && .AVIATION...(For the 00Z TAFS through 00Z Thursday evening) Issued at 728 PM EDT Wed Jul 20 2022 I am thinking solid VFR conditions through Thursday. That being said, there is an area of showers over WI, north of MKE, that is moving quickly to the southeast. This will bring a period of very light rain showers to most of the TAF sites between 8 pm and midnight. Skies will clear after that. It should be mostly sunny Thursday. The next system brings increasing clouds mid to late afternoon with showers possible after 00z on Friday. The winds will becoming gusty once again but not nearly as gusty as there were today. && .MARINE... Issued at 807 PM EDT Wed Jul 20 2022 Wind gusts are below 15 knots at all near shore sites and near shore buoys. The wave heights across our near shore waters at all buoys are 2 feet or less. So, I have allows the headlines to expire. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM DISCUSSION...MJS AVIATION...WDM MARINE...WDM
Area Forecast Discussion
National Weather Service Wilmington NC
944 PM EDT Wed Jul 20 2022 .SYNOPSIS... A mid-level trough will drift east over the area the next few days, maintaining afternoon storm chances. A cold front will approach Thursday before stalling to the west of Friday, bringing unsettled weather through the end of the week. A strong ridge of high pressure will build into the Southeast this weekend with above normal temperatures expected across the Carolinas. && .UPDATE... Update this evening has mainly focused on updating PoPs based on radar trends. Late afternoon/early evening convection has dissipated, and cluster just NW of the CWA is weakening rapidly. Will carry a small chance PoP far inland for a couple more hours, then only slight chance for the duration of the night, as instability has become marginal with the loss of heating. HRRR had been indicating redevelopment east of I-95 late tonight, but last few hours it has backed off. Latest guidance suggests that most redevelopment will hold off until after sunrise. A Heat Advisory remains in effect for Thursday, as high temps in the mid 90s and dewpoints in the mid 70s combine to produce heat indices of 106-108 away from the immediate coast. The extent of convection could play a role in keeping heat indices lower than currently forecast, especially if it fires up early. Winds over the area waters are gusting 25-30 kt with seas running around 6 ft. Small Craft Advisory remains in effect tonight through Thursday night. && .NEAR TERM /THROUGH THURSDAY/... Convection ongoing, should endure through at least 8pm if it doesn`t push off the coast earlier. Slightly cooler temperatures aloft associated with little trough feature is allowing for possibility of hail this afternoon with more robust CBs that shoot up or above 40 kft. Plentiful CAPE, and large downdraft CAPE values make localized damaging downbursts a possibility as well through at least afternoon. The pattern of reflectivity shows how the upper trough is involved, with some inklings of organization. Quieting, breezy overnight in boundary layer ahead of approaching trough, this to prevent fog. Pre-frontal trough and heating Thursday to allow for 2 rounds of convection potentially. Large SBCAPE expected, could enhance downburst damage potential. The SPC placing us in marginal risk of severe TSTMs Thursday, slight risk to our west. Strong heating and high dewpoints requires a heat advisory for Thursday. && .SHORT TERM /THURSDAY NIGHT/... In the mid-level, the trough over the east coast will be its deepest and gradually weakening through Friday night. A cold front will be approaching the Appalachian Mountains at the surface and stall over the Carolina Piedmont. A 500 mb short-wave pressure trough will be over the region on Thursday and moves out of the forecast area Thursday night. This trough will provide synoptic lift reflected in the model omega fields. 2" plus precipitable water will be over the region through the period. The 0-6km storm motion indicates cells will be between 10 to 15 knots. So isolated areas will receive heavy rain, and strong wind gusts from the thunderstorms Thursday are possibly isolated, especially in areas away from the coast. As the frontal boundary weakens and leaves our area, the warm moist environment will remain entrenched for the entire period. Highs on Friday will reach the lower 90s inland and the upper 80s at the beaches. Heat Indices will reach into the lower 100s just below criteria for much of the area. The scattered thunderstorm can be expected to help moderate these heat indices. Low are expected in the middle 70s inland and upper 70s at the beaches. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... The forecast has not changed much over the past 12 hours. The Bermuda high-pressure ridge will be set up to the east, and troughs in the eastern United States are expected to be weak through the period and will not have much impact to our area. A dominant southwest flow with diurnal convection each day is expected. Temperatures will warm, and heat indices will be above 100 degrees most days and will be close to heat advisory each day. Highs each day will approach the middle 90s inland to near 90 at the beaches. Lows are expected in the middle 70s inland and the upper 70s at the coast. && .AVIATION /02Z THURSDAY THROUGH MONDAY/... Isolated convection is ongoing within our CWA but impacts should be minimal to none as storms fizzle out with loss of heating. We will monitoring a line of storms to our NW which could impact KFLO and KLBT within the next couple of hours. Some guidance is showing the possibility of shortwave energy moving in overnight which could reignite storms. SW winds will return tomorrow gusting around 20-25kts as a cold front approaches the area. Showers and storms could pop up earlier in the day near this boundary. Extended Outlook...Sub-VFR conditions possible each day in showers and thunderstorms, with the greatest chance in the afternoon/evenings. Stratus and fog may produce mainly MVFR visibilities or ceilings overnight into early mornings. && .MARINE... Through Thursday... Advisory ongoing for SW gusts between 25-30 kt and 6 ft seas offshore. Additionally, TSTMs will add another layer of hazard this forecast period, as an approaching surface trough interacts with Bermuda High pressure offshore. Strong SSW wind-seas, steep and full of chop, will mix with SE waves of 1-2 feet every 8-9 seconds, the Bermuda swell. TSTMs will cause locally higher winds and seas, and dangerous cloud to water strikes this period. Seas should peak at 6- 7 feet late Thursday offshore mainly in steep SW wind-waves before a slow. Thursday Night Through Monday... A front will approach but stall over the Piedmont beginning Thursday night. The pressure gradient between the trough and the Bermuda high will weaken. Southwest winds are expected throughout the period. Wind speeds near 20 knots will occur Thursday evening, and the winds will weaken by 10 to 15 knots by Saturday evening and remain at this speed through Monday. Sea heights will drop for 5 to 6 feet Thursday evening, subsiding to 3 to 4 feet by Sunday into Monday. && .ILM WATCHES/WARNINGS/ADVISORIES... SC...Heat Advisory from noon to 8 PM EDT Thursday for SCZ017-023- 024-032-033-039-054>056-058-059. Beach Hazards Statement from 6 AM EDT Thursday through Thursday evening for SCZ054-056. High Rip Current Risk from 6 AM EDT Thursday through Thursday evening for SCZ054. NC...Heat Advisory from noon to 8 PM EDT Thursday for NCZ087-096- 099-105>110. Beach Hazards Statement from 6 AM EDT Thursday through Thursday evening for NCZ106-108-110. High Rip Current Risk from 6 AM EDT Thursday through Thursday evening for NCZ110. MARINE...Small Craft Advisory until 5 AM EDT Friday for AMZ250-252-254- 256. && $$ SYNOPSIS...ILM UPDATE...CRM NEAR TERM...08 SHORT TERM...RH LONG TERM...RH AVIATION...LEW MARINE...08/RH
Area Forecast Discussion
National Weather Service Nashville TN
804 PM CDT Wed Jul 20 2022 ...New UPDATE... .UPDATE... Issued at 753 PM CDT Wed Jul 20 2022 It`s a warm and juicy evening across Middle Tennessee. The majority of the obs are still 90 degrees or above with dew points in the 70s. The heat advisory and excessive heat warning were allowed to expire for the evening. Wayne, Lawrence, and Giles still have the heat advisory for Thursday from 10am-6pm. Looking at the 00z OHX sounding, there`s ample CAPE this evening with mlCAPE values around 3500 J/kg and surface based CAPE values around 4500 J/kg. Shear is on the weaker side with 10 kts of effective shear, but looking upstream into southern KY, 20 to even 25 kts can be found. The better shear values upstream are expected to make it into our area later this evening. High resolution models have been showing storm development that is starting to occur in southern Kentucky and even the northern part of our area. Some of this wave is expected to clip the northeast part of Middle Tennessee later this evening. Some damaging wind gusts cannot be ruled out with that activity. The other area to watch is the activity along the Kentucky/Illinois border. HRRR has come more in line with the NAM 3km in bringing that wave of storms into the area around midnight and later. Even with the overnight time period, ample CAPE will still be around along with 20-25 kts of effective shear. Therefore, damaging wind gusts will remain a threat overnight. && .SHORT TERM... (This afternoon through Thursday Night) Issued at 219 PM CDT Wed Jul 20 2022 The theme for the short term is definitely HOT, maybe some rain, and not as hot. But before we get to the good part, Highs today have been well into the 90s with heat index values solidly in the mid 100s this afternoon. However, a nice little front will push through the area overnight bringing showers and thunderstorms to much of Middle Tennessee. A few of those storms could be strong overnight, but definitely not expecting widespread severe weather. Thanks to the above mentioned front, think most of Middle Tennessee will be free from any Heat Advisory or Excessive Heat Warning outside of far Southern Middle Tennessee on Thursday. I think we can all agree that heat index values in the 90s are slightly better than the 100s. But just slightly. && .LONG TERM... (Friday through next Wednesday) Issued at 219 PM CDT Wed Jul 20 2022 Hot and dry weather pattern sets up Friday through at least Monday with temperatures returning to the mid to upper 90s and heat index values racing back to the 100s. Another round of Heat Advisories and maybe even Excessive Heat Warnings will likely be needed for the weekend. The next chance of rain after tonight looks to be Tuesday and into the middle of next week as we return to a not as hot weather pattern with typical summertime afternoon and evening convection. && .AVIATION... (00Z TAFS) Issued at 547 PM CDT Wed Jul 20 2022 Hot and unstable airmass in place across the mid state this afternoon. However, large subsidence is the rule and for the most part is preventing any convective activity at this time across middle TN. There is a cold front a couple hundred miles off to our northwest with some pre frontal convergence now taking shape just north of the Ohio river. As the front slowly drops southward...we will see this developing area of convection move our way overnight. Thunderstorms will be possible for the taf areas as early as 02Z in the far NW near CKV, then for the BNA and CSV areas as we move toward 06Z-08Z. For now, will add some convective wind gusts but that may need to be increased going forward. Otw, after the storms move out, which will be by 10Z or so, we should have more tranquil conditions. Look for light northwest surface winds on Thursday with lower humidity by the afternoon. Still rather hot with highs in the 90s still. Cloud cover will be generally scattered with a trend toward "few" as we reach the mid afternoon hours. && .PRELIMINARY POINT TEMPS/POPS... Nashville 75 95 71 97 / 50 10 0 10 Clarksville 73 95 68 98 / 40 0 0 0 Crossville 69 87 66 90 / 50 20 10 10 Columbia 74 95 69 96 / 40 0 0 10 Cookeville 71 90 67 91 / 50 10 10 10 Jamestown 69 87 67 90 / 50 20 10 10 Lawrenceburg 73 94 69 95 / 40 10 0 10 Murfreesboro 73 95 69 96 / 40 10 0 10 Waverly 74 95 70 99 / 40 0 0 0 && .OHX WATCHES/WARNINGS/ADVISORIES... Heat Advisory from 10 AM to 6 PM CDT Thursday for Giles-Lawrence- Wayne. && $$ UPDATE.......Reagan SHORT TERM...Hurley LONG TERM....Hurley AVIATION.....21
Area Forecast Discussion
National Weather Service Pocatello ID
235 PM MDT Wed Jul 20 2022 .SHORT TERM...Tonight through Thursday night. Satellite imagery shows weak disturbance over northern Utah, slowly shifting east around the apex of 4-Corners high. Deeper low over northeast Pacific beginning to eject shortwave northeast toward Seattle early this afternoon. WSW flow aloft helping to keep moisture generally confined to areas directly adjacent to Idaho/Utah border. There could be enough instability for an isolated thunderstorm or two through the evening tonight as depicted by the hi-res guidance this morning. Otherwise the remainder of the forecast area is expected to remain dry. Similar conditions exist for Thursday, though aforementioned shortwave has now positioned itself along the PacNW coast from Seattle to Portland. Starting to see a response to this feature in the mid- level wind fields mainly across portions of the central mountains Thursday afternoon into the overnight, making for breezy conditions at ridge top. Shortwave drives east through the Idaho panhandle into Montana Thursday night and Friday, with most of the impact from this feature falling into the extended time range. DMH .LONG TERM...Friday through Wednesday. Upper shortwave drives east across the region Friday. Winds increase through the afternoon and early evening. Enough moisture could be pulled north into the region for isolated thunderstorms mainly higher elevations. Winds and humidities remain the greatest concern, with impacts for fire concerns across East Idaho. Conditions settle down Saturday as upper ridge tries to build into the region, though a lingering thunderstorm or two may still be possible. Another feature drives east Sunday for another potentially windy day, with continued fire related concerns. Ensemble clusters are all in favor of feature sliding through the PacNW at this time, though they do differ slightly on strength and depth of the feature. Monday and early Tuesday slightly cooler behind Sunday system under influence of northwesterly flow. Upper ridge strengthens again late Tuesday into Wednesday, stretching through the Great Basin toward the PacNW. GFS/ECMWF are slightly different in handling the ridge axis, leading to potential differences in temperature and wind trends through mid week. Conditions do look dry across the board however. DMH && .AVIATION... For the 18Z TAFS through 18Z Thursday. An area of high pressure will dominated the next 36 hours of the forecast. We are expecting some convective clouds over the higher terrain this afternoon especially along the southern parts of Idaho`s higher terrain. Ceilings will remain FEW to SCT becoming BKN at times across southern higher elevation zones associated with better chances for storm development. Afternoon showers, virga, and isolated thunderstorms will remain confined to the South Hills and Southeast Highlands south of the Snake Plain with HREF lightning probabilities increasing to a 10 to 20 percent chance of occurrence along the Utah and Nevada border regions. Best chances for VCTS will remain at KPIH and KBYI. Winds will also pick up this afternoon between 8 to 12 kts with gusts up to 20 kts. Clear skies return after sunset as chances for afternoon showers and storms tracks further south for Thursday. HRRR Smoke guidance shows continued smoke impacts today aloft from the Moose and Bray fires currently burning in the Salmon Challis NF and Magic Valley respectively. A westerly component to upper level flow will support smoke impacts above all terminals with best chances for near surface smoke across the Lemhi Valley, Upper Snake Plain, and Eastern Highlands. MacKay/Preston && .FIRE WEATHER... Upper ridge in place for now, but changes are forthcoming. Some lingering monsoonal moisture pooled over Utah has a finger or two stretching north into southern Idaho. Isolated storms remain possible along the Utah border through the evening, and afternoon winds are expected to be locally breezy but below critical fire thresholds. Similar conditions are expected on Thursday. A disturbance passes through the Idaho panhandle into Montana on Friday. Models have been trending slightly stronger with the wind threat, and all conditions are in place for a critical fire day, especially across the Salmon/Challis NF areas and the Upper Snake Plain. Combination of winds and humidities may approach critical thresholds in the Lower Snake Plain, and lower elevations of the Southern Sawtooth and Caribou NFs as well. Fire Weather Watch has been issued, and may be expanded if conditions warrant. A few thunderstorms may be possible as well as the disturbance pulls some moisture north into the region. Conditions settle down for Saturday, but a second disturbance shifts through on Sunday for another potential wind event and the next potential day of critical fire concern. DMH && .PIH WATCHES/WARNINGS/ADVISORIES... Fire Weather Watch from Friday morning through Friday evening for IDZ410-475-476. && $$
National Weather Service Raleigh NC
1015 PM EDT Wed Jul 20 2022 .SYNOPSIS... A cold front will approach from the northwest, then stall and dissipate over central North Carolina late Thursday night through Friday. && .NEAR TERM /THROUGH TONIGHT/... As of 1014 PM Wednesday... Lingering convection is rapidly dissipating with the loss of heating late and exiting mid-level wave. Just a few areas of rain remain as of 10 PM but expect dry weather by midnight. With nocturnal stabilization, do not expect re-development of storms overnight, however the HRRR is still showing some showers early Thu morning across central NC, while other CAMs remain dry. Will keep the slight chance for convection early Thu, but confidence is low that it will materialize. As per the previous discussion, increasingly- moist/humid low levels will likely result in the development and maintenance of areas of stratus/stratocumulus late tonight through late morning Thursday. Lows should bottom out in the low to mid 70s. && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/... As of 400 PM Wednesday... A Heat Advisory has been issued for the Coastal Plain, Sandhills, and portions of the northeast Piedmont of cntl NC for Thu afternoon- early evening. A broad trough from the Northeast nwwd across cntl and wrn Canada, and associated cyclonic flow aloft, will glance the srn Mid Atlantic this period. Wly 700-500 mb flow will consequently increase across cntl NC, ranging from around 15-20 kts over srn NC to 25-30 kts across nrn NC. At the surface, a lee trough will again sharpen over the NC Foothills and wrn Piedmont with diurnal heating, while a synoptic cold front will drift sewd and likely reach the NC Piedmont by Fri morning, where it will subsequently stall and dissipate. Continued swly flow ahead of the front will result in a slightly hotter and more humid airmass over cntl NC on Thu relative to previous days, with high temperatures in the low-mid 90s. When combined with afternoon dewpoints in the upr 60s to lwr 70s over the nw Piedmont to mid-upr 70s over the Coastal Plain, heat index values are expected to climb above 100 F throughout cntl NC, and above 105 over roughly the ern half of cntl NC. That heat and humidity will also favor the development of moderate instability, highest southeast, which should fuel scattered to locally numerous afternoon and evening storms, some of which may cluster into loosely-organized line segments capable of scattered damaging wind gusts. High Pws between 1.6 and 2.0" will also favor heavy rain and localized flooding. Areas of stratus and fog will result in the rain-cooled air overnight, with lows in the lwr-mid 70s. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/... As of 230 PM Wednesday... Heights aloft will increase late this week into this weekend as the upper trough to our north flattens and ridging to our west expands east. H500 heights will increase from 590 dam Friday to 593 dam by Sunday, with increased warming and drying aloft. H1000-H850 thicknesses remain steady between 1430-1450 m through the period. A stalled front to our northwest Friday will push back north over the weekend, with an Appalachian lee trough developing across our area and the Bermuda high set up to our east. The northwestern half of central NC will likely be too dry and stable for showers and storms to develop Friday through Sunday, however precipitable water values near 2" will linger near the coast through the weekend, and will likely be high enough to develop diurnal convection, especially Friday. There will be plenty of CAPE to support strong updrafts, but lacking shear will limit overall storm organization and likely result in short-lived pulse-type showers/storms. The ridge building in will increase highs from the low to mid 90s on Friday to the mid to upper 90s over the weekend. Heat index values will increase to the low to mid 100s for most areas, except for the Triad where lower dewpoint temps in the upper 60s will limit heat indices to the upper 90s. Wet Bulb Globe Temps (WBGTs) will rise into the high to extreme categories on Saturday, with most areas in the high category Friday and Sunday. These temperatures will create an increased risk for heat illness, and a Heat Advisory will likely be needed for several areas. Little relief will be provided overnight as lows only dip into the low to mid-70s. Ensembles are now trending towards lower heights aloft early to mid- next week with the ridge flattening and moving further west and a deeper trough developing across the Northeast. This will help lower highs slightly to the low to mid 90s, but also allow higher PWs to filter into the region and increase chances of diurnal convection, especially near the Appalachian lee trough. Unfortunately, the increasing moisture will continue heat index values in the upper 90s to low 100s early/mid-next week and WBGTs in the high category of heat stress for most areas. && .AVIATION /00Z THURSDAY THROUGH MONDAY/... As of 740 PM Wednesday... 24 hour TAF period: Showers and storms will move eastward through the area this evening, though if/when it clips the terminals is still uncertain and for now they are slipping between them all (closest at KINT/KGSO at TAF issuance). These storms should fall apart with loss of heating later this evening. However, some guidance suggests a regeneration of showers late tonight/early Thu morning, which could impact some terminals. Also of likely to occur (but low confidence on timing at a given terminal) will be the development of IFR-MVFR cigs tonight/Thu morning. Scattered storms, capable of 40-50 kt wind gusts, are expected Thu aft/eve. -KC Looking ahead: Areas of fog and stratus are likely late Thu night- Fri morning, particularly where the heaviest rain occurs beforehand. A lingering chance of both morning stratus/fog and afternoon showers/storms will focus over srn and ern NC through early next week. -MWS && .RAH WATCHES/WARNINGS/ADVISORIES... Heat Advisory from noon to 8 PM EDT Thursday for NCZ010-011-024>028- 040>043-075>078-084>086-088-089. && $$ SYNOPSIS...MWS NEAR TERM...KC SHORT TERM...MWS LONG TERM...JJT AVIATION...KC/MWS