Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/13/23

Area Forecast Discussion
National Weather Service Burlington VT
1031 PM EDT Fri May 12 2023 .SYNOPSIS... A couple of cold front will swing across the North Country overnight with just an isolated chance of a stray shower. Cooler temperatures arrive on Saturday and especially by Sunday on breezy north to northwest winds. Areas of patchy frost are possible on Sunday morning across portions of the region, as a dry weekend prevails. The next chance for rain showers will occur with another cold front late Monday into Tuesday of the upcoming week. && .NEAR TERM /THROUGH SATURDAY NIGHT/... As of 1021 PM EDT Friday...The axis of instability has proved me a fool tonight and has sustained showers across portions of northern New York and is now moving into Vermont. As such, highlighted an area of 30-50% chances of showers across the Adirondacks and central Vermont tracking these through over the next few hours. There was one cloud-flash, but conditions are pointing to shorter columns as surface temperatures cool below 70 degrees. While lightning is not expected, there is still about a 10% chance of one of these showers developing into a weak thunderstorm. Locations in Vermont that have the best chance of a shower include places between a Shelburne to Hinesburg line extending southward to Rutland over the next 4 hours. Previous Discussion...Cut precipitation chances this evening to below 20% in general as heating is lost. There are some returns popping up towards the St Lawrence Valley along an area of weak forcing, but these are likely pulsing as the oblique angle of the sun hits the mid layers of present clouds; expecting these showers to dissipate quickly after sunset. Otherwise, forcing is rather anemic with no appreciable moisture to work with in the lower elevations. Any showers that do form will likely be mostly virga except for higher terrain where showers could reach the surface. Previous discussion... Fcst concern is low prob of precip tonight, followed by temps/rh`s and winds on Sat into Sat night. Sfc analysis places first front near the International Border, while secondary cold front is over the northern Great Lakes. These boundary wl swing south acrs our cwa overnight, with just a schc of a shower. The HRRR/NAM and RAP all show the potential for a few spot shower as boundary interacts with slightly better moisture and instability acrs our fa this evening. Areal coverage of precip wl be very small and <10%, given deep dry layer btwn 850-500mb. Given advection type airmass in place, have kept very close to NBM for lows, which supports values in the lower 40s to lower 50s most areas. On Sat cwa is under moderate llvl caa on brisk northwest 925mb to 850mb winds of 30 to 40 knots. This upslope flow, lingering moisture and sfc heating wl produce scattered fair wx cumulus clouds, especially acrs the trrn, which is supported by soundings and upstream vis satl pics. However, soundings continue to show very dry air near 5000 ft, which should mix toward the sfc during the aftn/evening hours on Sat, resulting in min rh values in the 28 to 35% range. This combined with sfc winds of 10 to 20 mph with localized gusts 20 to 30 mph, wl cause some fire wx conditions, especially central/northern VT, including the NEK. After coordination with users, wl have midnight issue sps for anticipated conditions. See fire section below for additional details. Temps are 5 to 10 degrees cooler on Saturday with values mid 60s to lower 70s. Saturday night, sfc high pres noses into our cwa, but still noticing a slight gradient, so temps might not completely bottom out. Clearing skies and some decoupling of winds in deeper/protected valleys support lows upper 20s to lower 40s. A frost advisory maybe required in some areas where the growing season has started, it all depends upon the winds. We still have time to fine tune fcst. && .SHORT TERM /SUNDAY THROUGH SUNDAY NIGHT/... As of 236 PM EDT Friday...A dry but seasonably cool and breezy Mother`s Day is expected across the region as we remain under the influence of a departing upper trough to our east. To our west an expansive area of high pressure stretching from the Great Lakes to the northern Plains will help to create a modestly strong pressure gradient which combined with deep layer mixing owing to full sunshine by the afternoon, should support surface wind gusts in the 20-30 mph range. Surface temps will warm to about 5 degrees below seasonal normals in the upper 50s to mid 60s, then drop off Sunday night into the mid 30s to low 40s. Some isolated frost will be possible, but overall there should be enough gradient wind overnight to mitigate widespread issues. && .LONG TERM /MONDAY THROUGH FRIDAY/... As of 236 PM EDT Friday...Heading into next week, dry conditions will largely prevail as the aforementioned surface high pressure slowly drifts over the East Coast. The only period of exception will be late Monday through Tuesday where a cold upper level trough and associated surface front will drop southward from James Bay and likely produce scattered to numerous showers across the region, especially on Tuesday and across northern zones. Depending on the speed of the front, Tuesday could have a sharp temperature gradient from north to south as well with the GFS and ECMWF showing +18C at 925 across southern Vermont, while falling below +10C across the north in the afternoon. Clouds should inhibit heating a bit, but any breaks could support highs around KVSF/KRUT in the mid/upper 70s. Behind the frontal passage, dry conditions return for Wednesday through Friday with maybe a spot shower Weds as the upper trough exits. Wednesday will be the coolest day of the week with mean 925- 850mb temps around 0C supporting highs only in the 50s. Additionally, lows Tue/Wed night will support areas of frost where the growing season has begun outside of the Adirondacks and Northeast Kingdom. Temperatures rebound nicely though on Thu/Fri to normal and above in the 60s to low 70s for highs and mainly 40s for lows. && .AVIATION /03Z SATURDAY THROUGH WEDNESDAY/... Through 00Z Sunday...A couple of cold frnt will cross our taf sites this aftn into the overnight hours with main impacts being a wind shift to the north/northwest. Otherwise, very dry air aloft will produce VFR conditions at all sites for the next 12 to 24 hours with some fair wx cumulus clouds anticipated, especially during peak heating. A spot shower is possible with frontal passages, but impacts and probability of hitting a taf site is too low to mention attm. Winds increase 10 to 15 knots with gusts 15 to 25 knots on Saturday aft 16z. Outlook... Saturday: VFR. NO SIG WX. Saturday Night: VFR. NO SIG WX. Sunday: VFR. NO SIG WX. Sunday Night: VFR. NO SIG WX. Monday: VFR. NO SIG WX. Monday Night: VFR. Chance SHRA. Tuesday: Mainly MVFR, with areas VFR possible. Chance SHRA. && .FIRE WEATHER... Fire weather concerns develop this weekend with near critically low relative humidity values and breezy conditions, along with continued dry fine fuels per coordination with fire weather partners. The last widespread wetting rainfall occurred on May 2nd and 3rd across the region, while last nights front produced only a trace to localized amounts near a tenth of an inch. A cold front will produce cooler temperatures on Saturday, but breezy northwest winds of 10 to 20 mph with gusts 20 to 30 mph are expected, especially across northern and central VT, including the Northeast Kingdom, where green up has yet to occur. Scattered fair weather cumulus clouds will develop during the late morning into the afternoon hours on Saturday, which should help keep min rh`s values in the 28% to 35% range on Saturday. Lower relative humidities are anticipated on Sunday, but winds should be slightly weaker. Bottom line, based on coordination with VT Forest, Parks, and Rec a SPS will be needed for parts of northern and central VT, including the Northeast Kingdom to highlight concerns this weekend, as open burning is strongly not recommended, given the anticipated conditions. For northern New York no SPS is needed given the burn ban is still in effect and green up has mostly occurred where people live below 2000 feet. If you live in Vermont, please remember to obtain a burn permit prior to any burning and use caution if planning any outdoor burning this weekend. And as a reminder if you live in New York State a burn ban is in place through May 14th which means no open burning is allowed. && .BTV WATCHES/WARNINGS/ADVISORIES... VT...None. NY...None. && $$ SYNOPSIS...Taber NEAR TERM...Boyd/Taber SHORT TERM...Lahiff LONG TERM...Lahiff AVIATION...Boyd/Taber FIRE WEATHER...
Area Forecast Discussion
National Weather Service Fort Worth TX
646 PM CDT Fri May 12 2023 ...New Aviation, Short Term... .SHORT TERM... /NEW/ Update: Upstream convection to our west/northwest has been on the slower side of guidance in terms of development and upscale growth so far today. Most of this morning`s HREF suite has been way off the mark in terms of activity in southwestern Oklahoma, and was much too aggressive in depicting an MCS developing and sweeping through North Texas this afternoon/evening. Recent runs of the HRRR/WoFS have caught up to present radar trends, and are depicting a slower and more realistic scenario for the arrival of an MCS from the west later this evening/tonight. It does still appear that one or more MCS segments will organize from West Texas activity during the next few hours which will spread into most of the forecast area tonight. While this convection could pose a hail/wind threat on an isolated basis, the greater concern will be heavy rain and flooding, particularly west of I-35 where training convection is possible. The Flood Watch configuration remains adequate at this time, and no further eastward expansion is presently planned. There is still considerable uncertainty of coverage of thunderstorms tomorrow which will depend heavily on how convective trends evolve in the next 12 hours. -Stalley Previous Discussion: /This Afternoon through Saturday Night/ A warm and unstable airmass is in place across Central and North Texas this afternoon and some warm advection showers have started to develop beneath what was a fairly strong cap this morning. Latest RAP objective analysis and an aircraft sounding from earlier suggest this capping has weakened and we should see a slight uptick in scattered afternoon thunderstorms mainly south of I-20. This activity will be aided by weak ascent ahead of a slow moving upper trough over north-central Mexico. Farther to the northwest, a frontal boundary and surface dryline are positioned from north to south across western Oklahoma and into northwest Texas. A warm and humid airmass to the east of this boundary yields around 4000+ J/kg of most unstable CAPE and will fuel thunderstorm development through the late afternoon and early evening. It`s a little uncertain whether or not this activity will directly impact North Texas as the boundary is still displaced to the northwest, but several of the high resolution CAMs rapidly develop convection, then spread it east into North Texas along surging outflows early this evening. We`ll keep PoP around 30-40% across the northwest this evening with a substantial uptick in rain chances expected overnight. Any storms that develop this afternoon/evening have the potential to become severe with a damaging wind and hail threat. This severe threat will taper off tonight with heavy rainfall becoming more of a threat overnight. The aforementioned upper trough will spread out of northern Mexico and into the Southern Plains overnight tonight with persistent lift occurring throughout much of Central Texas. This should keep scattered to numerous showers and thunderstorms ongoing overnight, particularly west of I-35. As the trough continues northward on Saturday, a steady stream of moisture will persist through Central and North Texas with PWs increasing to 1.8". Deep meridional flow will favor training showers and thunderstorms which will likely produce bands of heavier rainfall. This is most likely to occur along and west of I-35, tied to the strongest forcing for ascent. Rain chances will continue into Saturday night across the entire region. A Flood Watch is in effect for areas west of I-35 currently, however, an expansion may be needed at some point over the weekend. Widespread rainfall amounts of 1-3 inches can be expected west of I-35 with lesser amounts to the east. The potential for training showers and storms means that some locations will likely see considerably more rainfall. Dunn && .LONG TERM... /Issued 323 PM CDT Fri May 12 2023/ /Sunday Onward/ With no significant pattern change in the forecast through the next week or so, expect an unsettled weather pattern to persist across North and Central Texas. Periods of heavy rain will increase the flash flooding potential, thus, a Flood Watch is in effect through Sunday evening. As we begin the new week, our region will be on the eastern periphery of a mid-level trough that will gradually be retreating eastward. Given the trough`s influence, southerly flow will continue to advect plenty of moisture northward into a weakly forced environment. Even with weak forcing, sufficient daytime heating will promote the development of isolated to scattered showers and thunderstorms on Sunday along any remnant boundary. The retreating trough will allow for an area of high pressure to shift eastward across the Lower Mississippi River. The weakened southerly flow may lead to a weak front moving in on Monday afternoon. Although there may be increased surface convergence along the front, weak deep layer shear and low instability should keep the threat for severe weather at bay. Weak impulses are likely to traverse across the region, and although overall storm chance will remain low, there will continue to be isolated to scattered showers and storms each day. The aforementioned area of high pressure will be temporary as the expectation is that by mid-week, the longwave trough across the eastern CONUS will strengthen and return an active weather pattern to our region to finish out the work week. As we approach next weekend, guidance continues to advertise a cold front moving into our region with high pressure settling in behind the front. If this is the case, there may be a break in precipitation next weekend. Hernandez && .AVIATION... /NEW/ /00z TAFs/ Timing of convective impacts to D10 airports has been pushed back slightly with the 00z TAF updates with radar trends and model guidance suggesting a North Texas arrival around/after 04z. While impacts to the western cornerposts are possible earlier than that, the most likely timing for storms in the immediate vicinity of the TAF sites is from 05-11z. Afterwards, lighter showers and probably less frequent lightning activity could linger into early Sunday morning before a break in activity through midday. Ragged MVFR stratus may attempt to develop during this time period as well, but any nearby convection could certainly interrupt or delay its formation. Isolated/scattered thunderstorm redevelopment is expected with daytime heating, and intermittent convective impacts seem likely through the afternoon and early evening period tomorrow. Outside of influences from thunderstorm outflow, a SE wind will prevail. -Stalley && .PRELIMINARY POINT TEMPS/POPS... Dallas-Ft. Worth 69 82 68 83 67 / 70 60 60 60 40 Waco 68 79 66 80 66 / 70 70 60 70 40 Paris 67 84 66 85 67 / 30 50 40 40 30 Denton 67 81 65 81 64 / 70 60 60 60 50 McKinney 67 82 66 82 66 / 60 70 50 50 40 Dallas 70 83 68 84 68 / 70 70 50 60 40 Terrell 69 83 67 84 67 / 30 60 50 50 40 Corsicana 71 84 68 85 67 / 40 60 50 50 30 Temple 68 79 66 80 65 / 60 70 60 70 40 Mineral Wells 66 78 64 78 64 / 70 70 70 70 60 && .FWD WATCHES/WARNINGS/ADVISORIES... Flood Watch through Sunday evening for TXZ091-100>102-115>117- 129>132-141>144-156>160-174. && $$
Area Forecast Discussion...Updated Aviation
National Weather Service Lincoln IL
1047 PM CDT Fri May 12 2023 .SYNOPSIS... Issued at 1033 PM CDT Fri May 12 2023 Periods of showers and thunderstorms are expected through the weekend, though it should not be a complete washout. With a front sitting on top of the area the next couple days, there will be some uncertainty as to location of the highest rain chances, depending on where this boundary is located. However, it currently appears the period from late Saturday afternoon into Sunday morning would be most favored. Some of the rain will be locally heavy, and expect a few of the storms to be on the strong to locally severe side. While Saturday remains warm and humid, with highs in the mid 80s, cooler weather is expected Sunday as the front begins to sink south. && .UPDATE... Issued at 833 PM CDT Fri May 12 2023 A stationary front was draped southeast across central IL, very near the I-74 corridor early this evening. Modest instability sampled at 1200 J/kg on 00z KILX sounding and weak convergence along the boundary have allowed isolated showers and storms to form from near Bloomington to Champaign over the past couple hours. With little upper level support these should fade over the next few hours, with only an isolated shower expected overnight near the front. Short range guidance is in good agreement that low clouds and fog will form in the weakly convergent and moist airmass along and north of the front after midnight, and persist into much of Friday morning. RAP/HRRR visibility plots show high probabilities of visibility near or below 1/4 mile, so dense fog will be possible at times, especially near and north of I-74. The very moist airmass will keep low temperatures 10-15 degrees above normal in the mid/upper 60s. 25 && .SHORT TERM... (Through Sunday) Issued at 246 PM CDT Fri May 12 2023 Main concern with this period is with convection through Sunday, and associated severe weather chances. Latest satellite imagery shows a bit of thinning with the clouds across central Illinois, though still mostly cloudy overall. Earlier rain activity has shifted to the I-80 corridor while further southwest, convection has been trying to get going across Missouri. While SPC mesoanalysis shows surface CAPE`s around 1500 J/kg west and south of Springfield and no cap, there`s not a lot in the way of forcing. Surface analysis does show winds turning more from the southeast to south between here and St. Louis, along a band of some light showers pushing across the St. Louis metro. High-res models have been advertising some development along this boundary through mid afternoon, with recent HRRR runs showing more of a focus across areas east of I-55 before fading away with diurnal heating. Highest PoP`s around 50% will be near/east of I-57 in this forecast package, though scattered showers/storms are included over the entire forecast area. Saturday and Sunday gets a bit more tricky with timing and intensity of convection. Upper low currently spinning over central Nebraska will gradually fade out Saturday morning, with the associated surface boundary extending east across central Illinois. This boundary doesn`t show much movement initially, as it is trapped between split upper flow to our east. Later on Sunday, it starts to get a southward nudge as a rex block develops over the Rockies. CAM`s generally show an area from north central Iowa into southwest Indiana where convection expands during the afternoon and evening, before weakening after midnight. No appreciable change was made in the most recent SPC Day2 outlook, mainly highlighting a level 1 (marginal) risk except slightly higher along and north of a Galesburg-Pontiac line where bulk shear is slightly higher in the 30-40 knot range at 0-6 km. Best chance of any tornadic activity would be in that area near and north of the boundary, but chances do not appear overly high (5%) at this time. Moving into Sunday, increasing shear values are mostly behind the front that drops southward, though they do appear decent near/east of I-57 during the afternoon where the SPC Day3 level 2 (slight) risk is placed. Temperature-wise, the humid conditions persist through Saturday, and temperatures appear to be highest during this period as highs reach the mid 80s across the forecast area. Sunday will feature more of a gradient, ranging from lower 70s north of the front to lower 80s south. Geelhart && .LONG TERM... (Monday through Next Friday) Issued at 246 PM CDT Fri May 12 2023 Sprawling surface high pressure will stretch from the central Plains to the mid-Atlantic as the work week begins, starting us off on the coolish side with highs in the lower to mid 70s. With a large upper low dropping southward across Quebec mid week, a backdoor cold front is expected to push through the area around Wednesday. Not much of a moisture influx is expected in such a pattern, so little in the way of rain is expected. Toward late week, longer range models all bring an upper low southeast from the Canadian prairies, reaching the northern Minnesota vicinity by Friday morning. The European model is the faster of the bunch in terms of both inflow of Gulf moisture, and the increase in rain chances. Anything on Thursday appears to be more of the pop-up variety as a weak wave cuts through across the state, with better chances accompanying the surface front Thursday night or Friday. A cooler pattern sets up as a strong ridge develops west of the Rockies, with the 6-10 day temperature outlook favoring below normal temperatures over the Midwest. Geelhart && .AVIATION... (For the 06z TAFs through 06z Saturday Night) Issued at 1047 PM CDT Fri May 12 2023 A stationary front was located just north of the I-74 corridor this evening, and is expected to move little overnight. An area of IFR/MVFR clouds has developed over southeast IL and was advecting north. Short range guidance is in good agreement that MVFR to IFR ceilings and visibilities will develop near and north of the boundary while the lower clouds from the south continue to spread north over the next few hours. The restricted ceilings/visibilities should affect all TAF sites except KSPI. Some improvement is expected by mid morning, then VFR conditions return around midday. Spotty showers are possible overnight, then a better chance for scattered storms develops late Saturday afternoon and evening. 25 && .ILX WATCHES/WARNINGS/ADVISORIES... None. && $$ WFO ILX
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
959 PM EDT Fri May 12 2023 .SYNOPSIS... High pressure continues to slide out into the Atlantic this weekend. A cold front will near the area on Saturday and track across ENC on Sunday, with a second front forecast to track across the region early next week. && .NEAR TERM /OVERNIGHT/... As of 955 PM Fri... A wonderful night to start our weekend as temps have fallen into the upper 60s to near 70 with rather comfortable dewpoints in place. High clouds continue to stream in from weakening shower activity well to the north and west as the western periphery of the Bermuda ridge remains over the Carolinas tonight. Prev Disc...Sub-tropical ridge remains planted over the southeastern CONUS this afternoon while the western periphery of the Bermuda high at the surface remains in control, although it is beginning to weaken slightly as a cold front crosses into New England. This boundary will eventually make it to our area on Sunday, but for tonight high pressure will remain in control. Deeper moisture will be slow to intrude into the region overnight, and lows will be only a couples degrees warmer than yesterday. && .SHORT TERM /SATURDAY/... As of 955 PM Fri...More active weather is expected tomorrow, although bulk of activity for eastern NC will likely not occur until the evening and overnight hours. A subtle shortwave is expected to traverse the mid- Atlantic tomorrow afternoon, helping to nudge the aforementioned cold front south. This will aid in the initiation of a cluster of showers and thunderstorms across central VA in the afternoon, gradually pushing south towards our area and reaching our NW`rn zones right around the end of the period. Our region should remain dry until then, owing to relatively lower Tds keeping instability almost non- existent - the ensemble max of the HREF only paints a couple hundred joules of SBCAPE across our northern tier through the day. Any showers and storms forming along the inland trough or the seabreeze tomorrow should fall apart, and opted to keep forecast dry until late afternoon when the better lift from the front and shortwave arrive. Low-level thicknesses are forecast to be similar to today, and carried almost the same high temps as today. && .LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/... As of 2 PM Friday...Semi-permanent ridging aloft will setup over the western half of the US into next week, with will keep a predominantly NW flow aloft pattern in place east of the Mississippi River Valley. Within this flow, a few shortwaves are forecast to move through the Mid-Atlantic/Carolinas. While medium range guidance are in pretty good agreement with the large-scale upper level pattern, there are some substantial differences with each individual shortwaves. The key takeaway here, then, is that the weekend through next week period still carries lower than normal confidence. With that in mind, a cold front crosses the area Saturday night- Sunday afternoon. This looks like a slower-moving front as it won`t have quite as much upper level support initially. Modest moisture and instability developing along the front should support scattered to numerous showers and thunderstorms. Deep layer shear and weak instability should keep the threat of severe weather low. Despite the increasing PWATs, the lack of stronger instability will probably keep rainfall amounts in check, and no hydro issues are anticipated. A quick-hitting system then moves through on Monday (almost more in an Alberta Clipper fashion). Despite the fast-movement, a quick round of showers and isolated thunderstorms appears plausible given the forecast lift, moisture, and instability. Shear will be better with this wave (compared to the weekend wave), but instability is lacking, so the net effect is a continued low risk of severe weather. Return flow quickly develops on Tuesday, followed by yet another wave moving through on Wednesday or Thursday. The moisture return, and associated chance of showers, is more questionable ahead of this wave, but we`ll continue to carry a slight chance/chance in the forecast for now. Temperatures will fluctuate from day to day depending on the timing of each wave and how much, if any, cold air advection occurs. The potential exists for parts of the area to end up cooler than currently forecast, especially if the surface low with any wave tracks inland/west of ENC. Near climo for most of the period, with Mon currently looking like the coolest day. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... SHORT TERM /Through Sat/... As of 7 PM Fri... Pred VFR conditions continue to persist across the CWA this evening with 5-15 kt S`rly winds noted across our terminals. Though winds will be light and skies will be mo clear across the FA, latest forecast soundings and a fair amount of forecast guidance outside of a seemingly overly aggressive HRRR don`t show a favorable environment for fog development tonight as high cirrus may remain thick enough and winds elevated just enough to preclude fog formation. Given this kept a VFR TAF through tonight as well. That being said, some patchy ground fog is certainly not out of the question especially along our SW`rn zones (think OAJ/DPL) tonight, though confidence is not high enough to include this in the forecast. Light winds will then increase out of the SW tomorrow after sunrise with 5-15 kt winds expected. A few gusts in the afternoon may approach 20 kts as well but these look to be few and far between. A gradually thickening and lowering clod deck will also be noted o SAturday particularly in the afternoon as a cold front approaches from the north. Don`t expect any precip through the period as well given the latest guidance but some showers may begin to sneak into the CWA SAt evening. LONG TERM /Saturday night through Wednesday/... As of 2 PM Friday...There will be an increased risk of sub- VFR conditions Saturday night through Sunday, and again on Monday, thanks to a pair of upper level waves moving through. Each wave will carry a risk of SHRA and TSRA as well, and possibly a period of gusty winds. There is potential for several hours of IFR cigs late Sat night through mid morning Sunday. && .MARINE... SHORT TERM /through Saturday/... As of 330 PM Fri...Quiet boating conditions across the waters this afternoon are expected to continue into tomorrow as the Bermuda high remains in control for the period. Southwest to southerly winds of around 10 kt are expected outside of the sea breeze circulation, where winds of around 15 kt are likely especially across the sounds. Winds will be strongest Saturday afternoon as front approaches from the north, compressing the pressure gradient, and a few spotty gusts up to 25 kt are possible in the afternoon. Offshore, seas hover at around 2-3 feet through the period with periods around 9 seconds. LONG TERM /Saturday night through Wednesday/... As of 2 PM Friday...A period of unsettled weather returns over the weekend, potentially lasting through much of the upcoming week. A cold front moves through Sat night into Sunday, accompanied by a risk of showers and thunderstorms. Gusty SSW winds 15-20 kt with occasional gusts to 25 kt develop Sat evening and Sat night, becoming northerly 10-20 kt behind the front Sun. Marginal SCA conditions possible Sat evening into Sun. Another front moves through on Monday with a similar risk of showers and gusty winds. Seas will gradually build during this time, with 3-5 ft seas common into early next week. && .EQUIPMENT... The KMHX WSR-88D radar in Newport, NC remains down for scheduled maintenance, and will be down for another one to two weeks for an important upgrade. During the downtime, adjacent radars will be available, including: KAKQ, KLTX, and KRAX. && .MHX WATCHES/WARNINGS/ADVISORIES... NC...None. MARINE...None. && $$ SYNOPSIS...MHX NEAR TERM...MS/RCF SHORT TERM...MS LONG TERM...RM AVIATION...RM/RCF MARINE...RM/MS EQUIPMENT...MHX
Area Forecast Discussion
National Weather Service Blacksburg VA
908 PM EDT Fri May 12 2023 .SYNOPSIS... A frontal boundary will arrive later tonight but stall across the Mid Atlantic. Chances of scattered showers with afternoon to evening thunderstorms should occur throughout the weekend and Monday. It will take until Tuesday for high pressure to arrive and provide drier weather. && .NEAR TERM /THROUGH SATURDAY/... As of 908 PM EDT Friday... Regional radar images showed convection diminishing this evening with the loss of solar heating. Elected to decrease pops tonight and keep the highest pops in the northwest as supported by the models. Adjusted temperatures tonight utilizing the latest surface obs,their trends and blended in the NBM. Added some fog overnight especially in the southwest mountains. A lee trough and cold font moving southward will spark the development of scattered showers and thunderstorms Saturday afternoon into Saturday evening. Previous: As of 551 PM EDT Friday... Scattered showers and thunderstorms have form this afternoon mainly along and west of the Blue Ridge. The best instability will remain to our west. Thus, the severe threat is limited. However, With a lighter mean flow, some storms could have locally heavy rains. Adjusted pops to match up with radar trends. Then, later tonight blended in the HIRESFV3 and HRRR for pops and weather. Also modified temperatures this evening into tonight to capture rain cooled locations. More changes later this evening.... Previous discussion: As of 155 PM EDT Friday... Confidence is moderate for scattered showers and thunderstorms later this afternoon and tonight. The models have again been too aggressive with bringing convective activity towards the Mid Atlantic as has been the trend for the past several events. Rainfall probabilities continue to be decreased as the radar shows little activity at this time. Showers and thunderstorms will eventually become more prevalent west of the Blue Ridge as a warm front approaches this evening. While the precipitable water in the 12Z RNK sounding is up to 1.33 inches, instability and wind shear are weak and not conducive to any severe potential. The warm front should stall across the Mid Atlantic tonight. Thunder chances will diminish with the loss of heating, but occasional showers and generally cloudy skies should remain throughout the night and into Saturday morning. If any areas receive notable rainfall, a little patchy fog may develop in between the rounds of showers. The chance of storms will increase by Saturday afternoon with locations east of the Blue Ridge have the higher chance, while the mountains may become too stable to support any notable convection. Temperatures on Saturday should be a few degrees lower compared to Friday. && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/... As of 230 PM EDT Friday... A buckling front near the area will be the focus for showers and storms Saturday night into Monday... A frontal boundary positioned over the area Saturday will sink south and stall by Saturday night. This front will then buckle slightly north and south as we progress through Monday, and then makes enough progression south on Monday night to clear precipitation chances. With this front so close to the region, and with weak periodic disturbances expected to ride southeast along this feature, we are expecting rounds of showers and storms across the area. Many of these will be diurnally based, but with enough support from the disturbances aloft to allow for overnight precipitation, especially Sunday night. A challenge remains exact timing of the greater chance of showers and storms Saturday night through Monday with guidance not consistent on the timing of the disturbances. Temperatures are expected to be nearly or slightly below normal for this time of year. Confidence in the above weather scenario is moderate. && .LONG TERM /TUESDAY THROUGH FRIDAY/... As of 100 PM EDT Friday... Unsettled weather through the period... On Tuesday into Wednesday, a broad upper trough will head southeast across Southeast Canada south into the mid-Atlantic region. Past this broader description of the synoptic pattern, details in the smaller scale weather patterns has considerable variability between the models and in time. The questions come in regard to how much, or how little, this northern system may interact with a southern stream shortwave trough that is expected to move somewhere across either the Tennessee Valley or northern edges of the Deep South Tuesday into Wednesday. Additional, the magnitude of precipitation associated with this feature have great variability among the guidance. Our latest forecast solution will be one that does not deviate greatly from our ongoing forecast. We will not have a completely dry forecast these two days, but no more than isolated diurnal coverage across the far southwest portion of the forecast area. Additionally, with the approach and then passage of the main upper trough, look for winds to become a bit gusty (10 to 20 mph) both days. Temperatures will be near normal each day. Thursday into Friday, an upper trough is expected to deepen across the central US and head eastward towards our region. The result will be shift in the prevailing wind pattern from northwest to south or southwest. This will allow for the advection of milder temperatures and higher dew point air into the area. The result will be increasing chance of daytime/evening showers across the region, with isolated daytime storms also possible, especially on Friday. Temperatures these days will be trending to values slightly above normal for this time of year. Confidence in the above weather scenario is on the low side of moderate. && .AVIATION /01Z SATURDAY THROUGH WEDNESDAY/... As of 735 PM EDT Friday... SCT MVFR convection will continue tonight mainly in the west. In the east, many locations will remain free of any rain. Clouds will increase this evening into tonight, and ceilings should lower to MVFR/IFR after midnight. Patchy fog will also be possible, especially for any locations that receive notable rainfall this evening into tonight. Ceilings will eventually improve to MVFR/VFR by Saturday morning, but there may still be ongoing showers. Scattered showers and thunderstorms will develop Saturday afternoon. Chances of thunder during Saturday afternoon may be highest for KDAN. Moderate confidence in ceilings,visibilities and winds during the taf period. EXTENDED AVIATION OUTLOOK... Poor flying conditions with ongoing chances of showers and MVFR/IFR ceilings will continue through the remainder of this weekend and into Monday. Thunder chances will increase during Monday. High pressure should arrive by Tuesday to provide VFR conditions. Wednesday may see a gradual increase in clouds and perhaps an isolated shower in the mountains. Isolated MVFR showers are possible in the western mountains Thursday. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...None. NC...None. WV...None. && $$ SYNOPSIS...PW NEAR TERM...KK/PW SHORT TERM...DS LONG TERM...DS AVIATION...KK/PW