Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 06/30/23


Area Forecast Discussion
National Weather Service Buffalo NY
1004 PM EDT Thu Jun 29 2023 .SYNOPSIS... It will become warmer and noticeably more humid as we push into the long holiday weekend...and unfortunately...this will include the daily potential for showers and thunderstorms. While it will become somewhat more unsettled...the vast majority of the Friday through Tuesday time frame will be rain free. && .NEAR TERM /THROUGH FRIDAY NIGHT/... The last few frames of visible satellite continued to show smoke across portions of western and north central NY this evening. The window of less smoke across western NY with visibility of greater than 6SM that was evident does seem to be closing as the observation at KBUF is now back down to 5SM. This seems to indicate that smoke across eastern Ohio is creeping back into western NY. Pleasant weather will continue tonight...as high pressure will exit across New England. Temperatures will run close to normal across the western counties...but will still average a few degrees shy of typical late June values for the Eastern Lake Ontario region. While the bulk of Friday will be rain free...the passage of a weak warm front and corresponding mid level shortwave will support scattered showers and thunderstorms. The system will also allow warmer and more humid air to spread across our region...and this will set the stage for uncomfortably high humidity levels for the upcoming long holiday weekend. Scattered showers and thunderstorms Friday evening will die off during the course of the night...as the passage of a mid level disturbance will help to shove a relatively deep plume of moisture to central and eastern New York. Apparent temperatures will climb to between 85 and 90 for Friday afternoon. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... A closed low just south of James Bay will move east across Quebec while an area of enhanced westerly flow will move across the Ohio Valley Saturday. Initially, showers will be diminishing and exiting to the east Saturday morning. Muggy conditions expected Saturday morning with dewpoints in the upper 60s. A cold front will approach western and north central NY through the day. The moist airmass will remain across the region with PWATS around 1.5 inches. Warm Saturday with daytime highs reaching the mid to upper 80s. Diurnal showers and thunderstorms will likely form by Saturday afternoon especially along lake breeze boundaries and inland areas. The fast westerly flow to the south may increase vertical shear profiles especially across western NY into Saturday evening. This may result in a few strong to severe thunderstorms. The "cold" front will move through the region Saturday night, which will bring a little relief to the humidity and a decrease in shower and thunderstorm activity. Low temperatures will fall to the low to mid 60s. Sunday will be another day of diurnal showers and thunderstorms, however there will be more emphasis across western NY as a frontal boundary lays near the New York and Pennsylvania border. This will be a zone of convergence with more widespread showers and thunderstorms and a potential of strong to severe storms, however confidence is low if they will impact western NY. Cooler and dryer air will filter into the North Country Sunday and while diurnal showers and a few thunderstorms can`t be ruled out, coverage will likely be lower than western NY. Highs will reach the upper 70s to low 80s Sunday. Activity should diminish Sunday night with lows reaching the 60s. && .LONG TERM /MONDAY THROUGH THURSDAY/... Upper/mid- level trough overhead of much of the Northeast throughout the first half of the week. A few hard to time shortwave troughs will rotate through, and combined with the daily diurnal instability trends along with mesoscale boundaries will support precipitation chances Monday and Tuesday. Additionally temperatures will range in the upper 70s and low 80s and conditions will be quite muggy. Wednesday and Thursday, the upper level pattern will begin to shift and supports an upper/mid- level ridge across the Great Lakes. With the ridging aloft and associated subsidence, chances for showers and thunderstorms will be lower than the days prior. Temperatures will be warmer mid week with highs ranging in the 80s, warmer temperatures occuring across the lake plains. && .AVIATION /02Z FRIDAY THROUGH TUESDAY/... Smoke from wildfires continues to be the main story for the terminals across western and north central NY through Friday. There is a window of less smoke from KBUF to KJHW where visibility is greater than 6SM. Satellite trends show the smoke moving into KJHW however the HRRR smoke forecast has this window persisting through tonight. Kept with current satellite trends with visibility coming down across western NY. Other TAF sites continue to produce visibility of 2-6SM. Conditions will likely stay the same overnight and into Friday morning. While mainly MVFR/VFR conditions will be in place across the region on Friday...the passage of a warm front will offer the potential for some showers and thunderstorms after 15z and mainly across western NY. Outlook... Saturday through Monday...Mainly VFR with scattered showers and thunderstorms. Tuesday...Generally VFR but with the low chance for a shower. && .MARINE... Fair weather and light winds are expected on the lakes through tonight as high pressure crosses the region. A few rounds of showers and thunderstorms are expected starting Friday and continuing into the weekend as an unsettled pattern develops across the eastern Great Lakes. Locally choppy conditions may develop in and around any thunderstorms. && .BUF WATCHES/WARNINGS/ADVISORIES... NY...None. MARINE...None. && $$ SYNOPSIS...RSH NEAR TERM...HSK/RSH SHORT TERM...HSK LONG TERM...EAJ AVIATION...HSK/RSH MARINE...Fries/RSH/TMA
Area Forecast Discussion
National Weather Service Cheyenne WY
526 PM MDT Thu Jun 29 2023 .UPDATE... Issued at 100 PM MDT Thu Jun 29 2023 As of 19z, several trends in satellite and mesoscale observations are becoming more clear as we head into yet another day of thunderstorm activity in southeast Wyoming and western Nebraska. The overall forecast highlighted in the early morning discussion remains on-track. GOES visible satellite imagery depicts a few areas of particular interest, the first of which is a pronounced cumulus field in southeast Wyoming, from Laramie county stretching north into the southern half of Platte and Goshen County. Surface obs validate the moist southerly flow seen in cloud motion over this region, with surface dewpoints generally in the mid-50s. Along the northern periphery of this cumulus cloud feature, surface flow and cumulus coverage appears to back westward a bit as flow spills up and over the broad elevation gap in the central Laramie range. To the west of this, a few high- based showers and thunderstorms have developed in the Snowy Range foothills and are drifting into the Laramie valley. A surface ob at KLAR of 78/48 with southeasterly winds gusting near 20 knots should be sufficient to sustain convection across the Laramie Valley. As thunderstorms interact with deeper moisture to the east, and surface flow backs even farther near the terrain gap in the Laramie Range, expect an intensifying trend to any dominant cells. This is supported by most CAM guidance, with the HRRR once again showing tremendous run-to-run consistency in one or two dominant supercells developing near the Chugwater/Wheatland corridor and moving east-southeast. Fast mid-level flow remains in place, and favorable hodograph size and shape in the lower-levels is progged through the mid and late afternoon hours. With time, convection may encounter capping farther east in the Nebraska panhandle, which may limit the eastward extent of the severe weather threat today compared to past days. Additionally, boundary-layer flow is much weaker farther east thus reducing hodograph shape which may ultimately result in a less-discrete storm mode once storms enter the Panhandle. The second area of interest is farther north, over the northern Laramie range where a severe thunderstorm has already developed over the higher terrain. An agitated cumulus field is noted to the east of this storm, with backed easterly flow up against the mountains observed at several obs sites. Surface dewpoints are a bit lower in this northern region, but the higher-elevation nature of the storm and a bit better hodograph shape at this stage of the afternoon will support a severe threat for several hours here as well. Mesoanalysis indicates significant capping east of I-25 in the Glendo-Torrington area, supported by a more laminar, matted appearance in visible satellite. If this capping can erode and destabilize, any dominant storms that continue off the northern Laramie range will pose a severe threat along and east of I-25 through the afternoon as well. Overall, large to very large hail remains the primary severe weather threat given supercellular storm mode, large bulk shear values, and a notable EML under deep surface moisture. A tornado or two is also possible, especially as dominant cells mature and interact with any lingering surface boundaries to the east. As storm mode transitions to multicell/linear mode farther east, a wind threat may develop. Finally, flash flooding remains a possibility in any area that sees multiple rounds of convection. && .SHORT TERM...(Today - Friday) Issued at 355 AM MDT Thu Jun 29 2023 Prior Discussion remains on track for this afternoon. Second paragraph discusses the Friday convective threat: The potential for scattered to numerous showers & thunderstorms w/ continued threats for extremely large, destructive hail, localized flash flooding, strong winds, as well as a few tornadoes continues to be the primary focus over the next 24 to 36 hours. Thunderstorm activity has remained fairly limited in coverage through the night across southeast Wyoming and the western Nebraska Panhandle, which will likely help keep thermodynamic profiles prime for yet another day of strong to severe thunderstorms. Thunderstorm coverage could be quite a bit higher today w/ much stronger forcing associated w/ a sharp upper-level trough poised to eject northeast across the 4- Corners region by late morning and early afternoon. Also, we could be looking at a much earlier start to convection w/ CI expected by 18z. Early-day surface heating coupled w/ ample low-level moisture characterized by surface dew points in the low & middle 50s should help support MLCAPEs of 1500+ J/kg in the presence of fairly steep mid-level lapse rates near 8 deg C/km. 500-mb flow in excess of 50 knots, coupled with pronounced low-level veering should contribute to 60+ knots of deep layer (0-6 km) vertical shear. Supercells are expected in this environment w/ very large/destructive hail likely to be the primary hazard, although line segments and some training could also lead to periodic high winds and potential for localized flash flooding. Forecast low-level hodographs are not particularly impressive for this afternoon & evening, but given the presence of pronounced low-level veering and very strong speed shear, isolated tornadoes are certainly possible especially w/ any supercells that can latch on to pre-existing boundaries. Like previous days, would expect the tornado threat to be maximized near the Platte, Goshen, Laramie tri-county region ( perhaps even slightly west into Albany County today) into the southern Neb Panhandle including Cheyenne & Kimball counties. This is where backed near-surface flow (courtesy of the Chugwater Cyclone) will contribute to enhanced convergence, as well as locally maximized effective bulk shear w/ effective SRH near 150 m2/s2. High-res CAMs are in excellent agreement with very intense & persistent UH tracks through these areas. Convection may very well last well into the evening & perhaps overnight w/ likely hazards transitioning more to small hail & flash flooding later in the event. The Friday forecast remains somewhat contingent on residual overnight thunderstorm activity from today`s round. Earlier short-term models suggested a mid-level vort max/MCV-type feature drifting over east-southeast Wyoming through the day on Friday. In more recent guidance, this feature is less apparent, suggesting a more chaotic, disorganized multicell storm mode. Despite residual surface moisture remaining in place on Friday (surface Tds at or above 50 east of I-25), surface flow is progged to be very meager, if not nill in most locations. Additionally, the pronounced southwest flow aloft is progged to shift eastward into the midwest, leaving flow of less than 25 knots in the mid-levels over southeast Wyoming and western Nebraska. This combined will reduce bulk shear values and greatly decrease hodograph size and curvature, thus resulting in a more typical summertime pop-and- drop convective mode compared to the discrete supercellular mode seen in past days. Heavy rain will still remain a threat, with plentiful moisture especially in the low-levels. Thus, the Flash Flood Watch will remain in effect through Friday`s convection. Expect thunderstorm activity to quickly diminish after sunset as heights begin to rise and dry air pushes in from the west. .LONG TERM...(Friday Night - Wednesday) Issued at 355 AM MDT Thu Jun 29 2023 Prior forecast remains on track and the previously issued discussion follows: An unsettled long term pattern is expected with daily chances for showers and thunderstorms across the region. A warming trend is expected through Monday before temperatures start to cool again on Tuesday. Severe weather is possible throughout the long term, but details for any specific day are still uncertain at this time. No major changes were made with this forecast package. As previously mentioned, the general upper-level flow for this weekend through early portions of next week is northwesterly flow aloft. Northwesterly flow aloft provides a more favorable environment for storms across the region as the several upper-level disturbances traverse across the CWA. By Wednesday, an upper-level trough begins to deepen over southern Canada and shift the upper-level flow to westerly as zonal flow builds in behind the Canadian trough. A cold front passes through the CWA on Tuesday, cooling temperatures for the 4th of July holiday. The passage of the cold front on Tuesday brings an increased threat for widespread showers and thunderstorms for the holiday. Trends will need to continue to be monitored, as an earlier frontal passage on Tuesday could retrain the amount of showers and thunderstorms to the earlier hours of the day. Severe weather is possible throughout the long term, as the CWA will be in a favorable regime for severe storms. The specific details for any day are uncertain at this point, but as of now the CWA is only in a general thunder risk for Friday. Trends will continue to be monitored, especially for the July 4th holiday as the synoptic pattern looks more favorable for severe storms given the cold frontal passage and favorable positioning of upper- and mid-level jet streams on July 4th. However, as the previous forecaster mentioned, 4th of July is still about a week away, so models could change for the holiday! && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 514 PM MDT Thu Jun 29 2023 Mainly VFR conditions across southeast Wyoming and the Nebraska panhandle with the exception of areas experiencing the line of thunderstorms stretching from near KCDR to near KCYS and moving eastward. Brief periods of MVFR to IFR conditions due to lowered VIS and CIGS are possible over the next 2 to 3 hours at KCYS, KBFF, KCDR, and KAIA. Areas of light fog are possible tonight following the thunderstorms, but confidence is low in timing and how widespread it will be. Additional thunderstorms tomorrow afternoon beginning near 19Z. && .FIRE WEATHER... Issued at 1225 PM MDT Thu Jun 29 2023 Negligible fire weather threat in the short-term period as abundant moisture from numerous thunderstorms keeps surface moisture in place. As we transition into the weekend, expect a drying trend with lower RH values and light westerly flow returning. This may raise the fire weather threat by later in the weekend and early next week. && .CYS WATCHES/WARNINGS/ADVISORIES... WY...Flood Watch through Friday afternoon for WYZ101-102-107-108-119. NE...Flood Watch through Friday afternoon for NEZ002-003-019>021-054- 055-095-096. && $$ UPDATE...MAC SHORT TERM...CLH LONG TERM...AM AVIATION...LK FIRE WEATHER...MAC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
537 PM CDT Thu Jun 29 2023 ...00Z AVIATION UPDATE... .SHORT TERM...(This evening through Friday) Issued at 236 PM CDT Thu Jun 29 2023 Key Messages: 1. Quiet night expected, with mild low temperatures. 2. Another active day is possible Friday, with a slight risk (level 2 of 5) of severe weather for southeast IA, northeast MO, and west central IL. This is the same area that saw severe storms today. Discussion: An MCS tracked east near the IA/MO border today into a very moist and unstable environment, bringing widespread damaging winds, at least one tornado, torrential rain, and frequent lightning to northeast MO and west central IL. Wind speeds in excess of 70 mph were reported in Clark county MO and Hancock county IL. In addition, rainfall amounts between 1-2 inches were reported in several areas along and south of I-80, along with cooler temperatures. Lastly, the strong winds aloft with this system has helped to mix out most of the smoke that we have been dealing with for the past 3 days. Some areas north of Hwy 30 still are reporting 1-3 mile vsbys from the haze/smoke as of 2 pm. However, the latest run of the HRRR smoke model continues to show an improvement this evening and overnight. Tonight...increasing subsidence aloft and weak high pressure will bring quiet conditions and calm winds. Overnight lows will only drop into the upper 60s. Friday...another strong wave will eject out into the Plains, with a surface low developing in KS by 12z. A warm front will be draped across northern MO through the day and will bring another round of storms to areas that saw activity today. The latest 18z RAP shows CAPE values over 2000 J/kg, PWATs over 1.7", and deep layer shear values between 45-55 kts. These ingredients all suggest severe weather will be possible and SPC has a slight risk (level 2 of 5) in our far south for this reason. All hazards (damaging wind, large hail, and a few tornadoes) will be possible. The one thing that I have seen that is different for this event than compared to today are the mid level lapse rates are somewhat lower (6-7C/km) and the mid level wave position is slightly further north. This just means that the confidence in severe weather placement and strength is lower. The latest CAMS/HREF progs suggest this activity will occur in the 12z to 20z window, which is the same as today. Left forecast highs in the mid to upper 80s alone for now, but these could be too high depending on cloud cover and anticipated storms. .LONG TERM...(Friday night through Thursday) Issued at 236 PM CDT Thu Jun 29 2023 Key Messages: 1. Active weather pattern continues through the weekend, with several chances of showers and thunderstorms and some much needed rainfall. Latest drought monitor released today showed an increase in severe drought conditions. 2. Warm and mostly dry weather expected early next week for the 3rd and 4th of July. Discussion: A positively tilted longwave trough will track over the Great Plains into Iowa this weekend. Large scale ascent with this wave in a very moist and high theta-e environment, will bring several rounds of showers and thunderstorms to the region. While there is still a lot of differences in projected totals, model ensembles and the NBM all support much of the area receiving at least an inch of rain this weekend. NBM probs (50-70%) of 1+ inch of rain are highest along and south of highway 30. This is good news to drought stricken areas, which has continued to worsen in recent weeks. For those with holiday weekend activities, not all of the weekend will be wet. The highest chances of rain (50-75%) at this time will be in the Saturday afternoon-Sunday morning time frame. Extensive cloud cover and rain will keep highs cooler this weekend, with readings in the low to mid 80s. Early Next Week...building heights aloft and weak high pressure will bring warm and mostly dry conditions to the area. This will be ideal for holiday festivities, with highs in the upper 80s/low 90s and lows in the low to mid 60s. Dewpoints are expected to remain in the 60s, making it feel not too humid. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 524 PM CDT Thu Jun 29 2023 IFR to MVFR visibilities in smoke may linger or develop with light winds. In addition, some fog is also possible later tonight with IFR to MVFR visibility restrictions pending cloud cover. Shower and storm chances will increase Friday AM as the next disturbance approaches. Best chances are favoring BRL after 12z to 18z where TEMPO mention was included and will have PROB30 mention at CID and MLI. Gusty winds and hail will be possible with the strongest activity. && .DVN WATCHES/WARNINGS/ADVISORIES... IA...NONE. IL...NONE. MO...NONE. && $$ SHORT TERM...Gross LONG TERM...Gross AVIATION...McClure
Area Forecast Discussion
National Weather Service Louisville KY
953 PM EDT Thu Jun 29 2023 .Forecast Update... Issued at 950 PM EDT Thu Jun 29 2023 Currently, radar shows a stronger storm over Grayson County, KY. Upstream in southwestern Indiana, there are a few more strong storms that will continue to move eastward. The environment as the storms move east is less favorable for development and maintenance, so they are likely to dissipate as they move eastward. The HRRR has been doing well today with the multiple rounds of storms that have moved through the area. Models suggest another round of scattered showers and storms to develop in the early morning hours around 04-05Z. These storms would develop over southern Indiana and move southward exiting the region around 12Z. With the rounds of showers and storms, the smoke has been moved out of the region and visibilities have been restored. && .Short Term...(This evening through Friday) Issued at 308 PM EDT Thu Jun 29 2023 Latest surface analysis reveals a serpentine warm front extending from low pressure centered over the IA/MO/IL border and winding southward along the MS River while sprawling high pressure extends across the East Coast. Current radar shows this morning`s convective complex exiting to our south into central TN as widespread rain slowly drifts south through south-central KY. Also evident and more concerning is a N-S oriented line of storms pushing through central IL, which will affect our CWA later this afternoon/early evening...more on this below. The above mentioned line of storms has developed on the nose of an 80kt 5H jet max, which continues to push ESE into Indiana. As the line pushes east into Indiana, uncertainty remains in the overall track. Latest SPC Mesoanalysis shows a much more favorable thermodynamic environment across northern Indiana and southward towards Paducah, with a more stable environment across our southern Indiana and central KY counties due to earlier convection. In fact, KY Mesonet shows current temperatures across central KY in the low 70s. Due to the uncertainties with the evolution of the line of storms, a Severe Thunderstorm Watch has been issued the includes a portion of our southern Indiana counties including Dubois, Perry, Crawford, Orange, and Washington. If the line maintains strength, damaging winds would be the primary hazard of concern with hail and a small tornadic threat as well. Again, confidence remains low with regards to exact strength of the system, so please stay informed to your local weather. CAMs have struggled with today`s convection and are currently struggling to initialize well with the location of the line of storms in IL, but there is general agreement in scattered convection overnight into the early morning hours of Friday. Synoptically, little change will take place tomorrow as upper level ridging remains in tact over ArkLaTex with troughing in Canada north of the Great Lakes. 5H convergence will once again see an uptick in winds aloft, which will likely result in another round of afternoon/evening convection for the region. Heat Advisory is still in play for tomorrow as high temperatures are projected to climb into the low 90s east of I-65 and into the mid 90s west of I-65. With surface dew points remaining in the 70s, heat indices could exceed 105F for areas west of I-65. .Long Term...(Friday night through Thursday) Issued at 230 PM EDT Thu Jun 29 203 Wet pattern, with some strong to severe storms, looks to persist into the weekend. A ridge across the Deep South will get slowly pushed southward this weekend, as a trough moves into the Midwest. Small disturbances riding across the quasi-zonal flow in between the two will mean additional waves of storms pushing west to east across the region. This pattern is difficult to peg the exact timing of best storm development as well as location, but we can have some confidence in probabilities of precipitation. Depending on timing during the peak heating can lead to severe weather too. Temperature forecasts are very tricky here, as more of a gap in the rains during the daytime will means highs reaching well into the 90s, with our southwest having chances to reach Heat Advisory or perhaps Excessive Heat Criteria. This call will have to be made likely the day of. The best chance for widespread rainfall looks to be Sunday, ahead of that upper low moving in from the Midwest. Coverage should be widespread enough to limit severe weather, but again some of this depends on how the previous waves of storms push thru Fri/Sat. As we get to Mon-Thu the flow aloft will become somewhat light and convection should be more pulse in nature. Temperatures look to be more summer like in that period given some better chances for sunshine each daytime period. One last thing to note, despite being abnormally dry for a bit, the latest drought monitor this morning came in with some improvement over the region. The rainfall we had west of I-65 earlier today and these next few waves coming in could bring up the risk for flash flooding. It will depend on training of storms and which locations receive several rounds of storms the rest of today through Sunday...so stay tuned for updates. && .Aviation...(00Z TAF Issuance) Issued at 730 PM EDT Thu Jun 29 2023 Discussion: Current radar shows a line of showers over Central Kentucky. This line consists of remnants from the earlier line that moved in from southwestern Indiana. The showers will continue to propagate eastward and dissipate over time. There is new robust convection which formed in southwestern Indiana that is moving into the region. It should be to HNB around 0Z. The environment southeast of HNB is not as conducive for convection, so this will dissipate as it moves eastward. Overnight, showers and storms will form and move southeast over the region. Being in a pattern as this, leaves more uncertainty in forecast timing. Tomorrow, we should remain mostly dry and hot under the upper-level ridging. Additionally, the rain today has most likely pushed the smoke out of the region that has blanketed the region for the past few days. The expectation is that visibilities will be better overnight because of this. Confidence: Medium-high confidence on the occurrence of showers and storms overnight, but confidence is low on timing and exact location. && .LMK WATCHES/WARNINGS/ADVISORIES... IN...None. KY...None. && $$ Update...SRM Short Term...CG Long Term...RJS Aviation...SRM
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
839 PM EDT Thu Jun 29 2023 .SYNOPSIS... Brief high pressure will build over the region through this evening as upper level troughing progresses east into New England. Dry and hazy conditions will continue as a result with additional Canadian wildfire smoke filtering in. Winds switch to the south Friday pushing the smoke out of the region with shower and thunderstorm chances returning Friday afternoon. These chances will continue throughout the weekend into early next week as an area of low pressure and its associated cold front approach the region. The front stalls nearby Monday before clearing the area midweek. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Dry and hazy conditions continue this evening with high pressure briefly building overhead. Northwest flow aloft continues to steer smoke from eastern Canadian wildfires into the region. Code Red Air Quality Alerts continue as a result for all of Maryland, northern Virginia, much of the Shenandoah Valley, and the eastern panhandle of West Virginia. Meanwhile, the upper-level trough to our north and east continues to progress east of New England, with the northeast extent of the upper-level ridge building into western sections of the forecast area. Any smoke and haze likely becomes trapped overhead as particulates become trapped beneath a strengthening nocturnal inversion. Additionally, expect a gradual uptick in moisture at the surface yielding dewpoints back in the 60s/70s over the next 24 to 36 hours. High cloud cover will work back into the region overnight. Eyes turn to the north and west as areas of positive vorticity advection shift southeast from the Ohio River Valley. This will steer multiple MCSs through the Midwest and into the Ohio River Valley/central Appalachians region. CAMS/obs/trends continue to suggest that this activity will stay south and west of our region into southeastern Ohio and southern WV through early Friday morning with maybe a few showers and perhaps a thunderstorm grazing the VA/WV Highlands late. Overnight lows will fall into the low to mid 60s west of the Blue Ridge Mountains, with values closer to 70 in the urban corridor. If we receive more cloud cover earlier, lows could be a little warmer. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Shower and thunderstorm chances increase into the weekend as a warm front approaches from the south. Brief high pressure will continue east Friday allowing warm/moist southerly advection to funnel in. Some smoke/haze will remain during the first half of the day, although air quality will gradually improve due in part to a change in wind direction. With the low-level wind shift, expect building mid-level heights as the stout upper- level ridge over the Gulf Coast nudges north and east over the region. This will yield much warmer temperatures Friday into the weekend while acting as a catalyst for increased shower and thunderstorm activity from multiple waves of energy pushing through. 12z CAM guidance suggests multiple convective waves tracking through Friday into Saturday. The first wave (per the HRRR and HREF) looks to slide south of the region Friday morning, with its residual outflows firing convection mainly west of US-15 Friday afternoon into Friday evening. A secondary wave of energy looks to impact the area Saturday as a warm front lifts into the region. Convective coverage combined with the severe threat appears to be higher with confidence increasing between model runs. For now, went with an uptick of shower and thunderstorm activity west of US-15 Friday afternoon into Friday evening. Coverage will be scattered in these areas and relatively isolated further east into the urban corridor due to residual dry air from the ridge aloft. Instability values run between 1000-2000 J/kg with vertical effective shear averaging between 15 and 20 knots in these aforementioned locations. Currently, the Storm Prediction Center has painted a Marginal risk for severe thunderstorms, mainly west of US-15 Friday, with wind and hail as the primary threats. By Saturday morning, the warm front should cross the region. Moist/warm advection will continue to increase along with instability during the afternoon and evening hours. This will yield a typical summertime regime of diurnally driven showers and thunderstorms. The focus Saturday will be along the front as well as across the high terrain, and potentially the bay/tidal Potomac due to the bay/river breeze. CAPE values will remain on the order of 1000-2500 J/kg with shear values around 30 kts. This will lead to a bit more organization with storms Saturday afternoon. Temperatures will be at or above average with muggy dewpoints areawide. Highs in the 80s, with a few spots going into the 90s east of the Blue Ridge and along the I-95 corridor are expected. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Starting off the long term period on Sunday, ridging will be in place across the southeast US, while an elongated northeast to southwest oriented zone of troughing will reside from Quebec and Ontario, across the Great Lakes, and toward the central Mississippi Valley. This zone of troughing will feature two more compact embedded shortwaves, with one located across southern Quebec/Ontario, and another further southwest across the central Mississippi Valley. Moving through the day Sunday, the northern shortwave will progress eastward across Quebec, while the southern shortwave starts to shear out a bit and become more elongated in the southwest to northeast direction as it tracks into the Great Lakes/Ohio Valley. This trough will slowly translate eastward on Monday, with the base of the trough tracking into Ohio and western Pennsylvania. As this trough tracks to our northwest, south to southwesterly return flow will develop in response, drawing very warm and humid air into the region. Highs on both Sunday and Monday are expected to reach into the upper 80s and low 90s, with dewpoints climbing into the lower to middle 70s. Winds in the mid-upper levels of the atmosphere will also be on the increase as the trough approaches the area. Our positioning downstream of the approaching trough will also place us in a favorable location for weak synoptic scale forcing for ascent. As a result, thunderstorms are expected to form across the area on both Sunday and Monday afternoons. With winds on the increase aloft, and increasing low-level moisture being drawn northward into the region, it appears as though this system may create a favorable overlap of moderate to high instability and appreciable wind shear, making strong to severe thunderstorms possible. Most model guidance shows around 30-40 knots of 0-6 km shear both days, which would be enough to get organized storms on its own. What`s particularly eye-catching though is that most of the shear occurs in the 0-3 km layer, with models showing 30-40 knots of flow at 700 hPa, which is highly atypical for early July (above the 90th percentile, and nearing daily maxes for the IAD sounding site according to the SPC sounding climatology site). Severe thunderstorm potential will be dependent on a number of factors, including convection from preceding days, as well as how the large scale pattern evolves. Given that it`s 4-5 days out, a lot can change, but we`ll continue to monitor the potential for strong storms Sunday and Monday over the upcoming days. The aforementioned trough will continue to progress eastward on Tuesday and Wednesday. This may allow for a greater northerly component to the low-level flow on Tuesday, and a resultant slight drop in dewpoints. While a stray shower or thunderstorm can`t be ruled out, the trough progressing to our east and a slight decrease in low-level moisture looks to make conditions a bit less favorable for widespread thunderstorms. Mid-level ridging will start to build overhead on Wednesday, making conditions a bit less favorable still. But as is often the case during the summer, a stray afternoon thunderstorm can`t be ruled out with the heat and humidity in place. Although dewpoints may be a few degrees lower (upper 60s), temperatures will continue to top out in the upper 80s and low 90s. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Haze and smoke look to remain the primary issue to aviation tonight. Vsbys continue to hover between IFR to MVFR at all TAF sites due to FU/HZ. Vsbys are expected to continue to hover between 2-5SM with SCT-BKN cigs between 030-060 through the night as particulates become trapped under a strengthening nocturnal inversion. Otherwise, dry conditions will continue with high pressure drifting by. Expect clouds increasing from the west Friday morning before a slow spread east as return flow ensues across the region and a storm complex dies to the south. This complex of storms will put off outflow boundaries that will be the focus for diurnally and terrain driven convection in areas near and west of KMRB/KCHO Friday afternoon. For now, went with a mention of VCTS at these terminals with lower confidence further east. Daily shower and thunderstorm chances increase into the weekend given moist southerly flow and upper disturbances tracking in from the west. As a result, expect brief restrictions each afternoon and evening as these storms move through. There is plenty of model variability in timing and placement of these features. Thus, will continue to favor the typical favored times of day for Mid-Atlantic warm season convection. Winds Friday will switch to the south and southeast with gusts up to 15 kts Friday afternoon and evening. Similar winds expected on Saturday and Sunday with a warm front nearby. Winds in and around thunderstorms would be stronger and more chaotic in nature. Mainly VFR conditions are expected for the end of the weekend and into Monday with occasional drops in conditions with any passing thunderstorms over the terminals in the afternoon and evening. Winds will continue to blow out of the S/SW during this period, as well. && .MARINE... Sub-SCA level winds will continue through Friday morning with light and variable winds as high pressure briefly builds into the region. Eventually, high pressure moves offshore yielding a pronounced period of southerly flow. Models continue to show an uptick in these winds Friday afternoon into early Friday night. Some southerly channeling of these winds along the Chesapeake Bay may lead to 18 to 20 knot gusts. Small Craft Advisories have been issued for the 18z to 03z period to cover this threat. Winds do become a bit lighter into Saturday. With convective chances returning on Friday and Saturday, thunderstorms may impact the waterways leading to hazardous conditions. Sub-SCA winds are expected Sunday into Monday. Special Marine Warnings may be needed both afternoons and evenings with any strong thunderstorms that cross the waters. && .TIDES/COASTAL FLOODING... Tidal anomalies are expected to hold relatively steady tonight, with some of the more sensitive sites entering action stage. Winds will turn southerly tomorrow, allowing anomalies to start rising. As a result, more sensitive locations like Annapolis may reach minor flood stage with the tide cycle tomorrow night, and other sites like DC SW Waterfront, Straits Point, and possibly Baltimore are likely to enter action stage, and may approach minor flood stage. && .EQUIPMENT... KLWX is in the final stage of an important upgrade. Technicians will refurbish and replace the pedestal, one of the most critical components of the radar, which is necessary for antenna rotation and positioning to capture data in all directions. The components are extremely heavy and will require the radome to be removed by crane and replaced when the work is completed. Estimated full return to service is still June 30th, barring any unexpected issues. During the downtime, adjacent radars will be available, including: Wakefield, VA (KAKQ), Roanoke, VA (KFCX), Dover, DE (KDOX), Charleston, WV (KRLX), Pittsburgh, PA (KPBZ), State College, PA (KCCX), and Fort Dix, NJ (KDIX)...also FAA Terminal Doppler radars for Dulles (TIAD), Reagan National (TDCA), Thurgood Marshall BWI (TBWI), and Joint Base Andrews (TADW). For direct access to any of these surrounding radar sites, visit the following Web page: https:/radar.weather.gov/ && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 2 PM to 11 PM EDT Friday for ANZ530>534-537>543. && $$ SYNOPSIS...EST NEAR TERM...DHOF/EST SHORT TERM...BRO/EST LONG TERM...KJP/ADM AVIATION...DHOF/ADM/EST MARINE...ADM/EST TIDES/COASTAL FLOODING...LWX EQUIPMENT...LWX
...Updated Aviation Forecast Discussion...

.DISCUSSION... Issued at 257 PM CDT Thu Jun 29 2023 Key Messages: - Another thunderstorm complex will move through the area late tonight into Friday morning with a risk for severe weather and localized flooding. - Storm chances remain in the forecast Friday into Saturday night. Some flooding and/or severe weather is possible. - Dry and warmer Sunday into Tuesday. Tonight into Friday morning: Satellite-derived total precipitable water and early afternoon surface observations indicate a w-e-oriented axis of richer tropospheric moisture situated along the NE-KS border, along and just to the north of the outflow boundary remnant from this morning`s MCS. That moisture axis is likely to drift north tonight in response to the development of a 20-30 kt low-level jet over KS, supporting air mass destabilization, at least across the southern half of our area. Meanwhile, thunderstorms currently developing over southeast WY are forecast to grow upscale into an MCS over portions of western into central NE this evening into tonight, aided by the interaction between amalgamating cold cools and the unstable downstream air mass. Latest CAM output offers various degrees of MCS organization and latitudinal variance in location by the time the convective system reaches our area after midnight. The past few runs of the HRRR have trended south with the most intense convection overnight; in line with the 12z runs of the NSSL-WRF and NAMnest. Given the current location of better moisture/instability (as mentioned above), we are leaning toward the more southern solutions. Accordingly, the greatest severe weather and heavy rainfall potential appears to be along and south of the Platte River and I-80. In other words, we could see a scenario similar to that which unfolded this morning. Damaging winds of 60-70 mph appear to be the primary hazard, though hail up to 1" and localized flash flooding are also possible. Storms are expected to exit our area between 7 and 8 AM Friday. Friday afternoon and Friday night: A midlevel trough currently over the Interior West is forecast to shift east into the northern and central Plains with showers and thunderstorms possible from Friday afternoon through Friday night. Model forecast soundings suggest that both shear and instability will be on the margins of that which supports organized storm modes. Nonetheless, isolated occurrences of hail and/or strong wind gusts cannot be ruled out. Highs Friday will be mainly in the 80s. Saturday and Saturday night: The above-mentioned, midlevel trough will continue east/southeast through the mid/lower-MO Valley with showers and thunderstorms appearing likely during the day, especially for locations south of I-80. Since sequential rainfall events will have likely occurred south of I-80 prior to Saturday morning, there could be an increased potential for flash flooding, as highlighted by the WPC Day 3 excessive rainfall outlook. Clouds and precipitation will likely to hold temperatures in the 70s to low 80s Saturday. Sunday through Wednesday: Midlevel heights will rebound Sunday in the wake of the shortwave trough passing to the east, and ahead of a strong low pressure system moving from western into central Canada. The Canadian system will eventually drive a surface cold front into our area by about Tuesday with the chance of rain increasing Tuesday night into Wednesday. Daytime temperatures are expected to warm from Sunday (highs in the 80s) to Tuesday (highs in the upper 80s to mid 90s), ahead of the approaching cold front. && .AVIATION...(For the 00Z TAFS through 00Z Friday evening) Issued at 634 PM CDT Thu Jun 29 2023 Expect another round of strong thunderstorms early Friday morning, though latest guidance suggests winds will not be as strong as they were this morning. Currently still some questions on exact timing and duration at any given TAF site, but consensus favors a relatively longer duration with repeated rounds of storms over 3-4 hours. A few showers may linger into Friday afternoon, but not expecting any impacts from those. Outside of storms, expect VFR conditions with mid to high clouds this evening and 8000-9000 ft clouds behind the storms on Friday. && .OAX WATCHES/WARNINGS/ADVISORIES... NE...None. IA...None. && $$ DISCUSSION...Mead AVIATION...CA
Area Forecast Discussion
National Weather Service Nashville TN
858 PM CDT Thu Jun 29 2023 ...New UPDATE... .UPDATE... Issued at 853 PM CDT Thu Jun 29 2023 Earlier convection has almost entirely dissipated over Middle Tennessee and the HRRR shows very little additional activity until after 10Z when MCS remnants are expected to enter the Upper Plateau. The evening sounding from OHX shows modest levels of instability even though we were sampling a post-storm environment. However, a rather pronounced inversion below ~875 mb appears to be keeping a lid on things in the near term. Have already made minor adjustments to evening POP`s. No further changes are planned. && .SHORT TERM... (This afternoon through Friday Night) Issued at 204 PM CDT Thu Jun 29 2023 Per current convection and latest CAMs, looks like mid state will not get as much temperature recovery as previously anticipated later today, and thus cancelled heat advisory. Will continue with excessive heat warning for Friday. Not great consensus in model specifics, so went close to previous forecast and previous forecast reasoning through Friday night. It is very hard unless you have a real dry airmass in place to reach century mark or go above it for the Nashville area. With scattered showers and thunderstorms possible Friday afternoon, have lowered temperatures a few degrees but unseasonably hot conditions expected no matter what as apex of upper ridging influences build across our area. Will keep lows tonight and Friday night seasonably mild. && .LONG TERM... (Saturday through next Thursday) Issued at 204 PM CDT Thu Jun 29 2023 Another heat advisory or excessive heat warning could be issued for Saturday, but need at least an additional model run suite for better clarity for issuance. Look for an unsettled summertime weather pattern to rule through next Thursday. A surface front meandering across our area on Tuesday will also aid in convection development potential. Temperatures will remain a few degrees above seasonal normal values through next Thursday also. && .AVIATION... (00Z TAFS) Issued at 628 PM CDT Thu Jun 29 2023 Outflow boundary moved through several terminals with gusts north of 30 kts around 2315Z, but has moved south now. Mostly VFR conditions are expected for this TAF cycle, however some storms are possible around sunrise for CSV/SRB. These could cause a reduction to IFR for a few hours. Winds will mainly be light with a westerly fetch on Friday. && .PRELIMINARY POINT TEMPS/POPS... Nashville 75 99 76 98 / 20 40 20 50 Clarksville 73 99 73 97 / 20 30 30 50 Crossville 65 89 68 89 / 40 40 40 50 Columbia 72 99 72 98 / 20 30 20 50 Cookeville 67 93 68 92 / 30 40 40 50 Jamestown 66 88 67 89 / 50 40 40 50 Lawrenceburg 71 98 71 97 / 20 30 20 50 Murfreesboro 71 99 72 98 / 20 40 30 50 Waverly 72 99 71 97 / 20 30 30 50 && .OHX WATCHES/WARNINGS/ADVISORIES... Excessive Heat Warning from 11 AM to 8 PM CDT Friday for Bedford- Cannon-Cheatham-Clay-Coffee-Davidson-De Kalb-Dickson-Giles- Grundy-Hickman-Houston-Humphreys-Jackson-Lawrence-Lewis-Macon- Marshall-Maury-Montgomery-Overton-Perry-Pickett-Putnam-Robertson- Rutherford-Smith-Stewart-Sumner-Trousdale-Van Buren-Warren-Wayne- White-Williamson-Wilson. && $$ UPDATE.......Rose SHORT TERM...JB Wright LONG TERM....JB Wright AVIATION.....Unger
Area Forecast Discussion
National Weather Service New York NY
1130 PM EDT Thu Jun 29 2023 .SYNOPSIS... Weak high pressure passing overhead tonight will pass offshore on Friday. A warm front will approach late Friday before stalling and weakening nearby Friday night into Saturday. The front will then lift through Saturday night, but then stall again nearby from Sunday through the middle of next week. && .NEAR TERM /THROUGH FRIDAY/... Subtle height rises take place tonight, with the more noticeable height rises at 700 mb into Friday. Enough capping will remain in place between 5 and 10 kft to preclude any precip chances for tonight and through the day on Friday. Later in the afternoon on Friday a warm front begins to approach from the west. This will usher in more in the way of mid level clouds late Friday afternoon into Friday evening. Previous HREF guidance indicated a slug of higher PoP associated with showers and thunderstorms into east central PA by late Friday/Friday evening. The newer HREF and HRRR guidance, along with the RGEM guidance, are less aggressive, and lead to further evidence of dry conditions continuing through all of Friday evening. The main question for the period is how much haze and smoke gets back into the area and how far east does it reach. There remains a lot of uncertainty with regard to visibility and the precise air quality impacts from smoke and haze associated with the Canadian wildfires and its associated smoke plume. For now have settled in with mainly 5-7 statute mile visibilities, but 3-4 statute mile visibilities at shorter durations are likely to take place for western portions of the CWA, including NYC. Temperatures are expected to average at near normal levels into Friday, with mostly clear skies. Mostly sunny conditions are anticipated Fri morning, although haze will be prevalent, followed by more in the way of mid level moisture and clouds later in the day on Friday. && .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY/... The newer HREF guidance along with the 12z Thu guidance of the higher res Canadian and other CAM guidance has it remaining primarily dry through Friday night. The cap however weakens during Friday evening. With a warm front going through frontolysis / weakening it is questionable as to how far east any shower activity can get. It seems prudent to have a slight chance of showers for at least a portion of the area Friday night as the warmer and more humid air mass begins to gradually begins to work in from the west along with a light onshore flow at and near the sfc out of the SE take shape. Therefore have gone only with slight chance PoPs for the western periphery of the CWA (mainly W Orange County) for most of Friday night. Introduce slight chance PoPs further east closer to day break on Saturday with some light showers potentially coming in out of the south off the ocean on a light onshore flow. Temperatures will not move much Fri night with lows in the 60s, with middle and upper 60s for the metro areas. Saturday will feature the more humid airmass getting more of a grip on the area as sfc dewpoints get into the middle and upper 60s. What is left of a warm front will stall nearby. The GFS and Hi-Res FV3 increase PW to about 1.5 inches by afternoon, with the NAM-3km delaying arrival of the higher water content relatively speaking. BUFKIT forecast soundings indicate a good deal of mid level moisture, with the sfc to 5 kft layer being relatively drier, especially for eastern portions of the CWA. Slight chance to chance showers seems prudent for the time being for daytime Sat. Kept thunder chances minimal as the instability remains back to the west for the first half of the weekend with the area not yet in the warm sector. Temperatures will be a few degrees warmer Fri night, and perhaps a few degrees cooler on Saturday due to more in the way of clouds. Temperatures overall will be right around the seasonable norms. With regard to the smoke and haze, after consultation with the NYS DEC and inspection of the HRRR, the Canadian RAQDPS, and the experimental RRFS there remains some question as to how long the plume lingers across a good portion of the CWA. At this time for Fri night it appears that the higher concentrations of haze and smoke may begin to dissipate and start to lift further north, with the higher probability of this taking place for Sat. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... After the passage of a cold front on Saturday, a warm front will bring increasing moisture and lift Saturday night The warm front then begins to pass through the forecast area Saturday night. Rain chances will continue until Monday morning with the passage of the warm front. Slight chance of thunderstorms early in the night. An unsettled period is expected in the long term as a weak frontal system lingers over the area. Based on the 12Z GFS a plume of high moisture air consisting of 2-2.25 inch PWAT values will move into the area Sunday. These PWATs are above the max moving average for this time of year per SPC`s Sounding Climatology Page. This has been consistent in the last several model runs. Elevated PWATs just under 2 inches (reaching about 2 inches, at times) sticks around through Tuesday. After mainly zonal flow aloft on Sunday, a trough will approach and be slow to pass to our east. This set up will likely result in showers and thunderstorms each day. At this time, widespread hydrologic impacts are not expected. WPC has outlined the whole CWA in a marginal risk in their Day 4 excessive rainfall outlook, with only portions of northeast NJ and the Lower Hudson Valley included in a marginal risk for Day 5. Additionally, the experimental CSU machine learning severe weather forecasts have our area in a marginal risk of severe weather each day in the forecast, mostly from daily diurnal convection. Temperatures will run right about average, with highs in the 80s each day and a slight warming trend. Given the high moisture and lack of clear nights, lows will be well above average, in the upper 60s to lower 70s. && .AVIATION /04Z FRIDAY THROUGH TUESDAY/... Weak high pressure passing overhead tonight will pass offshore on Friday. Still seeing MVFR vsby in haze/smoke at KSWF/KHPN, and it should make a return during the daylight hrs, affecting all the NYC metros and points north/west. Sea breezes should lead to late day improvement. Winds tonight become light and variable, then the synoptic flow becomes S 5-10 kt daytime Fri. ...NY Metro (KEWR/KLGA/KJFK/KTEB) TAF Uncertainty... Sound breeze may prevent MVFR vsby from directly affecting KLGA though there will still be haze aloft. Otherwise, unscheduled AMD not expected unless MVFR vsby in haze develops sooner than fcst. OUTLOOK FOR 00Z SATURDAY THROUGH MONDAY... Friday night: Chance of showers/MVFR cond, with possibly a tstm at KSWF. Saturday and Sunday: Showers likely and chance of tstms, mainly each afternoon/evening. MVFR expected, IFR possible with this activity. Monday and Tuesday: MVFR possible. Chance of mainly afternoon/evening showers/tstms. Detailed information, including hourly TAF wind component forecasts, can be found at: https:/www.weather.gov/zny/n90 && .MARINE... No advisories are expected for the coastal waters on a light S-SE flow to round out the week. Ocean seas subside closer to 3 ft Fri into Fri night. The S to SE flow then may increase somewhat to begin the weekend with ocean seas getting closer to 4 ft by early Sat evening. Sub-advisory conditions are expected to prevail Saturday through Wednesday with a weak pressure gradient in place and a lack of significant swell. However, there will be a slight chance to chance of thunderstorms each day, which could result in locally hazardous conditions. && .HYDROLOGY... At this time there are no anticipated hydrologic impacts through Wednesday. Localized impacts may become possible toward Sunday, and it is still too early to pinpoint the details. && .TIDES/COASTAL FLOODING... A moderate risk of rip current development expected for Friday and Saturday on the ocean waters. With astronomical tides increasing this weekend as we head toward a full moon on Monday, minor coastal flooding may be possible with the evening high tide cycles from Saturday through at least Monday. Areas most likely to be affected are the south shore bays of Nassau, Queens and Brooklyn, Staten Island, and Southern Fairfield/Westchester Counties. && .OKX WATCHES/WARNINGS/ADVISORIES... CT...Air Quality Alert until 11 PM EDT Friday for CTZ005>012. NY...Air Quality Alert until midnight EDT Friday night for NYZ067>075-078>081-176>179. NJ...Air Quality Alert until midnight EDT tonight for NJZ002-004- 006-103>108. MARINE...None. && $$ SYNOPSIS...JE/BR NEAR TERM...JE/BR SHORT TERM...JE LONG TERM...BR AVIATION...BG MARINE...JE/BR HYDROLOGY...JE/BR TIDES/COASTAL FLOODING...
Area Forecast Discussion
National Weather Service Raleigh NC
1000 PM EDT Thu Jun 29 2023 .SYNOPSIS... Weak high pressure will extend into the Carolinas from the north through Friday. Hot and humid air mass will spread into the region for the weekend. Upper level disturbances will bring a chance of thunderstorms. && .NEAR TERM /THROUGH TONIGHT/... As of 1000 PM Thursday... The Air Quality alert for most of central NC will continue through midnight. Another Air Quality Alert will be in effect starting at midnight for the NC Piedmont and go through midnight Sat. For now the Coastal Plain remains code yellow for Friday. The 3-7 mile visibilities due to smoke will linger into tonight, gradually retreating nw through the night. No major changes to the forecast with the evening update. Brought a slight chance for showers into the NW a tad earlier, with some hi- res guidance hinting at that. Lows still expected to be in the mid to upper 60s. Surface high pressure will slowly slide eastward through the mid- Atlantic through tonight. Aloft, a disturbance will traverse the ridge, propagating generally southeast from the OH Valley into the TN Valley tonight. An MCS could develop over the OH Valley and move southeastward toward the Carolinas, but its timing and track are still a bit uncertain. Details should become a bit more clear over the next hour or two as it develops, but then the question will be whether it makes it over the mountains. && .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... As of 123 PM Thursday... Increasing heat and humidity / storm chances beginning Friday. The flow pattern consisting of the strong mid/upper ridge over the lower Mississippi Valley and a persistent NW flow around the ridge from IL/MO SE into the central and southern Appalachians will edge eastward in the coming days. This poses an increasing risk of thunderstorms and higher heat/humidity in the coming days, beginning Friday. The latest CAMS indicate the MCS of tonight (IL/KY to TN) may send MCV or outflow into western NC late tonight and Friday morning. The latest HRRR indicates some redevelopment of scattered showers/storms over portions of central NC, even before noon Friday. This seems plausible given that western NC will be on the leading edge of the return moisture and heat from the SW. This warm front will be located over the region Friday. Then, another MCS is expected to move SE from IN/KY into the central or southern Appalachians late Friday or Friday evening. This MCS may have more potential to move across the mountains late in the day or Friday evening. We will carry chance POP for now, mainly Friday afternoon and night until we can better pinpoint the timing/location of the best chance (favored corridor) of thunderstorms. Right now, highest POP west and lower POP far NE. The air mass on Friday will support highs in the mid 80s NW to the lower 90s S-SE. The higher heat and humidity will arrive especially over the weekend (with the chance of storms going up, to offer some relief). && .LONG TERM /SATURDAY THROUGH THURSDAY/... As of 305 PM Thursday... Saturday and Sunday mid to upper level ridging will be present over Central NC. By early next week a weak long wave trough will be dominant across the region through late week. As a series of MCSs move from the Ohio valley into the region over the weekend expect highest chance pops on Saturday afternoon, Sunday early morning, and again on Sunday afternoon. Medium range all models show multiple rounds moving across the region over the weekend, but timing differs slightly. By Wednesday, models begin to differ as another possible wet pattern sets up for the Mid- Atlantic region as a cold front movies into the region on Tuesday. This front is expected to linger for the second half of the week reducing temperatures for Tuesday and Wednesday to the low to mid 90s. Along with the chance of rain over the weekend, the big story is the heat. Summer is here, and it will be hot over the holiday weekend. Temperatures in the 90s combined with dew points in the 70s will result in heat indices in the low 100s on Saturday. Temperatures will increase Sunday and Monday with highs in the mid to upper 90s with heat indices in the 100-110 degree range. Thus, a Heat Advisory should be expected at least one of the days especially for areas south of the Triangle. && .AVIATION /00Z THURSDAY THROUGH TUESDAY/... As of 755 PM Thursday... 24 hour TAF period: Smoke originating from Canadian wildfires will continue to support periods of VSBY restrictions of 3 to 6 miles in a mix of haze through tomorrow. Ensemble/probabilistic forecast guidance continues to indicate the potential for some brief LIFR to IFR restrictions in fog/stratus between 10 to 13z, mainly INVOF KFAY, where BL dewpoints are expected to increase into the upper 60s/near 70. Any fog/stratus that does develop tomorrow morning should quickly scour between 13-14z. Model spread is high and forecaster confidence is lower than normal regarding the chances for showers and storms Friday morning and into the afternoon/evening as upper disturbances embedded in the NW flow aloft pass through the region. For now will keep any related sub-VFR restrictions confined to the Triad terminals(KGSO/KINT). However, an eastward expansion into KRDU and KRWI may be needed in future TAF updates. -CBL Outlook: A regime with late night and early morning fog and stratus along with scattered afternoon and evening thunderstorms is expected Saturday into Independence Day Tuesday. -Blaes && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Blaes NEAR TERM...KC SHORT TERM...Badgett LONG TERM...CA AVIATION...CBL/BLAES
Area Forecast Discussion
National Weather Service Blacksburg VA
1048 PM EDT Thu Jun 29 2023 .SYNOPSIS... Hazy conditions will persist through the remainder of the day due to smoke from wildfires in eastern Canada. A series of upper level disturbances will bring rounds of hit-and-miss shower and thunderstorm activity to the lower Mid-Atlantic into the weekend. A cold front will pass across the region on Monday, bringing a return of drier weather for the Independence Day holiday. && .NEAR TERM /THROUGH FRIDAY/... As of 1040 PM EDT Thursday... No significant changes to the forecast late this evening. Had a few showers develop over the West Virginia mountains around sunset, but those have since diminished. Some hi-res guidance does indicate showers may build back in over the mountains during the early morning hours, but have not seen a lot of consistency from the guidance in this. Regardless, have left a slight chance in the western zones to account for this possibility. As of 611 PM EDT Thursday... Made some minor adjustments to temperatures this evening into tonight utilizing the latest surface obs, their trend and blended in the NBM. Modified cloud cover for this evening into Friday morning. In general, increased clouds a little in the west. Adjusted pops and weather for tonight into Friday morning, shaped towards blend of HRRR and NAM. Low temperatures tonight will range from the upper 50s in the mountains to mid 60s in the piedmont. Previous discussion: As of 230 PM EDT Thursday... Hazy conditions continue across the lower Mid-Atlantic this afternoon due to smoke from wildfires in Canada, and multiple Air Quality Alerts remain in effect this afternoon given the high particulates that may cause respiratory problems for those who are sensitive. Otherwise, satellite imagery indicates mostly clear skies, with fair weather cumulus across the Piedmont, as well as high clouds trickling in from the west due to thunderstorms moving south over Kentucky/Tennessee. Another thunderstorm complex over Illinois continues to make its way east. While the remainder of today will remain dry, high resolution weather forecast models are coming into better agreement this afternoon that the storms over Illinois/Indiana will make their way east during tonight, with the eastern fringe of this activity advancing to Interstate 77 by around sunrise Friday. By that point, believe that the storms will have weakened significantly, with mainly only rain showers remaining. Uncertainty increases at this point in the forecast as to how convection will play out during the day on Friday. Some data suggests that the early morning storms will leave an outflow boundary draped east of the Blue Ridge, which will provide the focus for renewed convection with mid-afternoon heating. Other data suggests that debris clouds will linger across the region into early afternoon, limiting heating and therefore making for a more muted redevelopment of shower and thunderstorm activity on Friday afternoon. For now, will err on the side of a wetter forecast, where storms may refire across our area with afternoon heating, though this could change with the evening or overnight shift as new data comes in. Went a couple degrees cooler for afternoon temperatures for Friday, reflecting the possibility of outflow from showers and storms before maximum heating occurs. && .SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY NIGHT/... As of 140 PM EDT Thursday... An upper level ridge over Louisiana will track east to the southeastern coastal states over the weekend. Impulses are expected to move along the outer rings of this ridge and over our region into Saturday night. On Sunday, an upper level trough will push a weak warm front north of the area. Models agree that storms will move over the area Friday night into Saturday night, but differ on timing, track and areal coverage. For Friday evening, the first impulse should decay as it sinks south into North Carolina. There is a Slight Risk for severe storms from Summers County WV to Watauga County NC westward. The rest of the area is in a Marginal Risk. A stronger complex is likely Saturday and the entire area is under a Slight Risk. For both events, damaging winds are the primary threat. There is also a Marginal Risk for excessive rainfall with each system. The passing of a warm front will change our convection mode from organized to disorganized diurnal pulse storms. Temperatures will run near normal Saturday with upper 80s to lower 90s east of the Blue Ridge and 80s west of the Blue Ridge. Temperatures should be a few degrees warmer on Sunday. Heat indices may hit triple digits in the piedmont Sunday afternoon. && .LONG TERM /MONDAY THROUGH THURSDAY/... As of 150 PM EDT Thursday... The upper level ridge is expected to move over the western Atlantic on Monday. Meanwhile, the upper level trough will move across the Ohio Valley pushing a cold front over the region Monday afternoon and evening. With a moisture-laden atmosphere and ample instabilities, another round of strong to severe weather is possible Monday, especially along and east of the Blue Ridge. The passing of the front Monday means Tuesday July 4th may be clear of any rain as high pressure begins to build over the region. High pressure should remain in the area into Thursday. Temperatures will continue to run near normal with warm afternoons and muggy nights. && .AVIATION /03Z FRIDAY THROUGH TUESDAY/... As of 735 PM EDT Thursday... Hazy conditions continue across the lower Mid-Atlantic this evening into tonight due to smoke from wildfires in Canada, resulting in widespread visibilities in the 3SM to 6SM range due to haze. Otherwise, satellite imagery indicates mostly clear skies, with high clouds and SCT VFR CU. Expecting CU fields to dissipate with the loss of solar heating tonight. A few showers or perhaps a storm may hold together to make their way into western portions of the forecast area to near BLF by around sunrise Friday. Believe convection will weakened significantly, with rain showers remaining and a westerly wind shift late tonight into Friday morning. How storms develop for Friday afternoon becomes less certain as some data suggests storms refiring across the Piedmont with afternoon heating, and other data suggests that convection will be muted due to residual clouds from morning activity that will limit heating. While TAFs reflect some convection redeveloping during Friday afternoon, have low confidence on the timing and placement of this activity. EXTENDED AVIATION OUTLOOK... Friday night into Sunday, the opportunity for SHRA/TSRA increases. Rounds of convection will continue to advance east from the Midwest and Ohio Valley through this period. The opportunity for rain will actually help clear the smoke/haze, allowing for generally VFR outside of any sub-VFR restrictions from the showers/storms. On Monday, sub-VFR showers and thunderstorms are possible especially in the west. Scattered MVFR convection is possible Tuesday especially in the mountains. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...NF NEAR TERM...BMG/KK/NF SHORT TERM...RCS LONG TERM...RCS AVIATION...KK/NF