Forecast Discussions mentioning any of "HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/16/22

Area Forecast Discussion
National Weather Service Charleston SC
1044 PM EDT Mon Aug 15 2022 .SYNOPSIS... A cold front will move into the region tonight and Tuesday, lingering in the vicinity through late week. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... Late evening SPS mesoanalysis indicates that the forecast area is covered in at least 50 J/kg of CIN. MLCAPE generally ranged around 500 J/kg. Based on the latest run the HRRR and regional radar trends, convection will likely continue to weaken as it pushes towards the coast. The forecast will continue to feature mentionable PoPs, with values as high as likely across Berkeley County. However, the intensity will be lowered below moderate. Most activity will have diminished or exited the area by daybreak, but a few showers will remain possible with the front still in the vicinity. Low temperatures tonight will mainly be in the lower 70s, except in the mid 70s closer to the coast. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/... Tuesday through Thursday: A weak front is poised to drift into the forecast area Tuesday morning and help serve as a triggering mechanism for showers and thunderstorms into the afternoon. Model consensus favors the coastal corridor for the best coverage and that is where the highest rain chances have been placed, including a small area of 50-60 across eastern Berkeley and Charleston counties. Wednesday is a trickier day as some model solutions show the boundary shifting offshore and further south. If this were to occur the focusing mechanism could actually be aligned across south Georgia and be displaced southward of the forecast area. Looking ahead to Thursday, it appears the boundary will drift back northward and become aligned across the forecast area. As this occurs, the trough aloft should start to amplify in response to an upper low developing and shifting southward out of Canada and into the Upper Midwest and Northern Plains. Precipitable water values are progged to surge in excess of 2 inches, setting the table for more widespread thunderstorm coverage and the potential for locally heavy rainfall. The highest rainfall chances are advertised in the Thursday period, with 60-80 percent across the forecast area (highest for southeast Georgia). && .LONG TERM /THURSDAY NIGHT THROUGH MONDAY/... The late week and weekend period continues to look active across southeast Georgia and southeast South Carolina. The subtle boundary is expected to remain in the vicinity with ample available moisture. Rain chances in the 50-60 percent range are in place each afternoon and evening. There are some indications that as we progress into the late weekend and early next week the boundary will wash out and we could return to a more typical scattered diurnal thunderstorm coverage regime. Temperatures should run a few degrees below normal for mid to late August. && .AVIATION /03Z TUESDAY THROUGH SATURDAY/... The main challenge with the 0Z TAFs will be the timing and placement of showers and thunderstorms later this evening. Based on the latest run of the HRRR, showers and thunderstorm coverage appears the greatest near KCHS and KJZI between 3-6Z. The TAFs will highlight the potential for convection with a TEMPO, featuring a TSRA. In addition, KCHS, KJZI, and KSAV TAFs will indicate VCSH from late this evening until close to daybreak Tuesday morning. During the daylight hours Tuesday, winds will veer through the day, turning from the NW by late afternoon. Extended Aviation Outlook: Mainly VFR conditions expected. Brief periods of flight restrictions will be possible in showers and thunderstorms through the weekend. && .MARINE... Tonight: South to southwest winds will continue overnight ahead of a weak area of low pressure and associated front moving into the area. Speeds will increase a bit to become a solid 15 knots with higher gusts, but conditions will stay below small craft advisory criteria. Seas will mainly be 2-3 feet. Tuesday through Saturday: South to southwest flow in the 10-15 knot range will prevail Tuesday before turning lighter and northerly to northeasterly Wednesday. Through the rest of the week and early in the weekend winds should no more than 10-15 knots with southerly flow returning Friday. Overall conditions should remain well below Small Craft Advisory thresholds. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...None. SC...None. MARINE...None. && $$ NEAR TERM...NED SHORT TERM...BSH LONG TERM...BSH AVIATION...NED MARINE...BSH/ETM
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
647 PM CDT Mon Aug 15 2022 ...New AVIATION... .SHORT TERM... (Tonight through Tuesday night) Issued at 231 PM CDT Mon Aug 15 2022 Increased organization occurred on the low pressure system that developed some tropical characteristics after the center made landfall, and this made for an active pattern over our western half of the forecast area this afternoon. A sharp contrast between the cool outflow and outer band allowed for a few tropical circulations to develop within the stronger cells, but no wind damage reports have been collected thus far. Radar loop over the outer banding region has since trended toward a much reduced threat for rotational cells closer to the Highway 281 corridor. However, a slow intensifying trend appears to be taking shape over the Rio Grande generally near and to the south of Eagle Pass where some insolation has destabilized the air closer to the low pressure center. This could be a brief focus for a tropical funnel cloud threat through around 00Z, with lowering temperatures likely to allow for a weakening trend to begin in that region. A local minima of activity is generally what we expect to see in the hours 00Z through 05Z based on a good consensus of the Convective Allowing Models; however, recent runs of the HRRR might signal some overreaction of a potential flash flood outbreak over the Eagle Pass area in the early evening. We think this might be a slight overreaction of the afternoon HRRR runs and will stick with the previous runs for that activity minima. It is only mentioned here to acknowledge that not all models show the same signals. What is more in harmony is the model depictions of a redeveloping trend of feeder cells in the overnight and early morning hours over Val Verde County, especially the western portions. While it`s somewhat unusual for offices to issue a Flood Watch for one county, Val Verde is a large county and the impacts of a 2 to 6 inch rain will have greater impacts than over an area where canyons and dry washes in a very rural environment could make for a lot of low water crossing that could be quite dangerous. This is also a region where tropical features sometimes interact with the local terrain and nocturnal onshore winds to overachieve in their ability to generate a deep swath of early morning training of heavy rain cells. The parent low should continue to pull northwest, and we think this threat should abate in the late morning hours. Rain chances in the late morning may still be elevated through the afternoon over the watch area and parts of the Rio Grande plains; however, there is no support from the Convective Allowing Models to carry the threat that far out in time. A few showers and storms could perk up from residual moisture pooling in the late morning Wednesday along the Rio Grande, but for the most part, high pressure will regain control. Meanwhile the parched areas of Central Texas will continue to see above normal levels of heat and humidity, leaving a stark contrast for the high temperature for Tuesday between western and eastern counties. Humidities will remain elevated for all areas, keeping the nighttime temps warm and muggy. && .LONG TERM... (Wednesday through Monday) Issued at 231 PM CDT Mon Aug 15 2022 Wednesday is a transition day on temperatures out west due to all the rain that has fallen. Central TX continues to see near triple digit heat and elevated heat indices of 102 to 107 degrees. The pattern will change yet again Thursday, as increased troughing over the eastern CONUS brings unstable northerly flow aloft and pooled mid level moisture south into Central TX. Thursday max temps are trending cooler over northern counties to signal some possible cool storm outflows pushing into the Hill Country and Central TX early in the day. The pattern of instability, wind, and moisture will be more similar to the pattern seen last week where storms take on more of a hit-and-miss nature. Hopefully Central TX counties do miss on this pattern which should begin to wane Friday evening. By the weekend, broad ridging develops over TX, but models keep above normal levels of moisture over the area and thus a small chance for isolated air-mass storms going into early next week. This might not be unreasonable, but seeing how the previous cycle of pattern have operated in this very dry summer, the more probable scenario is that these rain chances decrease as we get closer in time to those days. && .AVIATION... (00Z TAFS) Issued at 647 PM CDT Mon Aug 15 2022 MVFR to possibly IFR conditions will prevail at KDRT through at least the first half of the TAF period, with a period of MVFR cigs expected at the remaining terminals during the early morning hours on Tuesday. Showers with embedded thunderstorms will continue through the evening at KDRT as a low originating from the Gulf continues to move further inland. Precipitation coverage is expected to diminish later tonight, though the cloud cover will linger with ceilings potentially dropping below 1 kft AGL. The nearby moisture will aid MVFR cig development at the remaining terminals during the early morning hours, with the greatest confidence at KSAT and KSSF. For the most part, light southeasterly winds are expected through the period. The exception is KDRT where frequent gusts to 20-25 kts are expected, especially with any thunderstorms. && .PRELIMINARY POINT TEMPS/POPS... Austin Camp Mabry 76 101 77 101 / 0 0 0 0 Austin Bergstrom Intl Airport 74 99 75 101 / 0 10 0 0 New Braunfels Muni Airport 74 98 75 101 / 0 10 0 10 Burnet Muni Airport 74 98 74 100 / 0 0 0 0 Del Rio Intl Airport 75 91 76 94 / 70 40 10 20 Georgetown Muni Airport 75 100 76 102 / 0 0 0 0 Hondo Muni Airport 74 96 75 97 / 10 10 0 0 San Marcos Muni Airport 74 99 73 101 / 0 10 0 0 La Grange - Fayette Regional 75 100 75 102 / 0 10 0 0 San Antonio Intl Airport 75 96 76 97 / 10 10 0 10 Stinson Muni Airport 76 97 76 98 / 10 10 0 10 && .EWX WATCHES/WARNINGS/ADVISORIES... Flood Watch through Tuesday morning for Val Verde. && $$ Short-Term...Oaks Long-Term...Oaks Aviation...Gale
Area Forecast Discussion
National Weather Service Goodland KS
523 PM MDT Mon Aug 15 2022 .UPDATE... Issued at 458 PM MDT Mon Aug 15 2022 With the potential for strong, slow moving storms across northeast Colorado into this evening, have issued a Flood Watch for potential for flash flooding through 09z Tuesday. Storms over the Denver metro area have already produced flooding with 1-3" rainfall amounts. Flash Flood 1hr/3hr guidance is showing 1 to 2 inches of rain to cause potential flooding in localized areas. && .SHORT TERM...(This evening through Thursday) Issued at 215 PM MDT Mon Aug 15 2022 Concerns remain the same as previous forecast, namely, low end risk for landspout/thunderstorm development this afternoon across southern portion of the forecast area along old outflow boundary from last night, and second a risk for locally heavy rainfall tonight north of Interstate 70/west of Highway 25. Visible satellite imagery this afternoon is showing little development along the outflow boundary, with all of the cumulus south of it where intense surface heating is occurring. SPC non-supercell parameter not picking up anything either. Nonetheless, pattern suggests a non-zero risk given the boundary, but confidence in development there is low. Meanwhile further north, cumulus developing across northeast Colorado and western Nebraska may be more indicative of things to come. MLCAPE has increased to around 1500 j/kg in a very moist airmass with dew points in the lower 60s. Latest run of the HRRR suggesting convection will develop in southwest Nebraska later this afternoon and early evening, then merge with large cluster of storms coming out of northeast Colorado associated with the synoptic scale forcing. May see a few severe storms early in the evening, with wind being the primary hazard, and perhaps an isolated hail threat with stronger updrafts, though deep layer shear is on the lower end and will limit the potential for hail. Storm intensity will begin to wane towards 06z with loss of heating, but showers/isolated storms will linger well into the overnight. Low temperatures will be in the 60s. For Tuesday, scattered showers/isolated storms will continue into the morning hours, with a general southward trend through the afternoon. Clouds will be slow to erode, especially in eastern areas, and have lowered temperatures across the board, with highs mainly in the 70s. The next round of storms for Tuesday afternoon and evening will develop south of the Palmer Divide and along the Front Range in southern Colorado, moving east into the adjacent plains mainly south of the area Tuesday night. Cannot rule out a stray shower or storm further north, but chances will be low. Temperatures Tuesday night will fall into the low to mid 50s. For Wednesday and Thursday, upper flow will be very weak out of the northwest as ridge amplifies over the western CONUS and a trough develops near the Great Lakes. Temperatures will slowly rebound, with highs on Wednesday in the lower 80s and highs on Thursday in the upper 80s to around 90. Precipitation chances will be relatively low given the lack of upper forcing, although there is another weak cold front/wind shift Thursday night which may serve as a focus for isolated shower/thunderstorm development. Low temperatures will be in the 50s both days. .LONG TERM...(Friday through Monday) Issued at 1249 PM MDT Mon Aug 15 2022 At the start of the long term, we`re situated between two upper- level lows - one to our north-northeast and another over the western CONUS. Early in the period a surface low sweeps a boundary across the area with surface winds shifting northerly. Afternoon highs will be near normal on Friday, in the 80s. We remain under northwesterly flow aloft, gradually becoming more westerly into the weekend as the trough progresses eastward and upper-level ridging builds in. Embedded disturbances keep chances for showers and storms with PWAT values increasing above an inch Saturday afternoon onward. Slightly below normal high temperatures Saturday through Monday, in the upper-70s to mid-80s. Overnight lows will be in the mid-50s to low-60s. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday evening) Issued at 523 PM MDT Mon Aug 15 2022 With the region lying near a couple frontal boundaries, there will be the potential for mixed flying conditions through much of the forecast period. Currently VFR will prevail then shift to a MVFR/IFR mix as ceilings lower, especially from 06z Tuesday onward. BKN-OVC007-020 expected. VCTS/-TSRA possible after 04-05z. Locally heavy rainfall is possible that may help to reduce visibility. Winds for KGLD, north-northeast around 10-20kts w/ gusts approaching 30kts after 04z Tuesday. Winds for KMCK, north- northeast 10-15kts. Gusts up to 25kts 17z-22z Tuesday. && .GLD WATCHES/WARNINGS/ADVISORIES... KS...NONE. CO...Flood Watch until 3 AM MDT Tuesday for COZ090>092. NE...NONE. && $$ UPDATE...JN SHORT TERM...024 LONG TERM...CC AVIATION...JN
Area Forecast Discussion
National Weather Service Grand Rapids MI
736 PM EDT Mon Aug 15 2022 LATEST UPDATE... Update/Aviation .UPDATE... Issued at 736 PM EDT Mon Aug 15 2022 I added showers to Tuesday afternoon`s forecast too. Looking at tomorrow, both the NAMNEST and HRRR have significantly more precipitation forecast tomorrow than today over the GRR CWA. Tomorrow there is not a thermal inversion near 700 mb like there is today. That results in equilibrium level for convection is significantly deeper tomorrow than today. I will admit there is more dry air aloft above 600 mb than today, even so the air is fairly moist to about 15000 ft so I would think with an upper low near by, deep northeast winds and some surface heating, we would see showers again tomorrow, so I put 20 to 30% POP in the forecast for Tuesday and increased the clouds over some. UPDATE Issued at 526 PM EDT Mon Aug 15 2022 I have updated the forecast to allow for rain showers over the I-69 area early this evening. There is just enough instability for scattered rain showers on the lake breeze convergence boundary. At 520 pm there is a line showers from north of Lansing to near Jackson. The showers are shallow since there is an inversion near 12000 ft capping the convective cells. The showers may be briefly heavy but total precipitation will likely be less than a tenth of an inch since the showers will be brier. Once the sun sets the convection should come to an end. && .DISCUSSION...(This evening through next Monday) Issued at 256 PM EDT Mon Aug 15 2022 Diurnal showers across the eastern half of Lower Michigan should be decreasing and ending by this evening. Quiet weather this week under surface ridging and dry northeast low level flow. The upper pattern transitions to an Omega block by the end of the week as an upper low dives south from northern Canada and becomes vertically stacked to our west with a moist southerly flow developing. Showers should move in from the west by Saturday as the deeper moisture and lift arrives and the slow movement of the low will keep showers lingering through Sunday and into Monday. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 736 PM EDT Mon Aug 15 2022 Overall VFR with northeast winds through Tuesday. The evening showers from today will be gone by 03z for sure, by then skies should become clear or nearly so. On Tuesday, it will be similar to today. Day time heating will cause convection to develop over eastern Lower Michigan by early afternoon then that will spread west into our CWA by mid afternoon. The shower may have slightly higher coverage than today. Even so, showers will be widely scattered so I put VCSH in most of our TAF forecasts for Tuesday. && .MARINE... Issued at 256 PM EDT Mon Aug 15 2022 Winds and waves will continue to be from the northeast through Wednesday and the offshore component will keep waves fairly light along the coast. There could be some choppy 2 to 4 foot waves near Big and Little Sable Points Tuesday afternoon as winds gust to 20 knots. && .GRR WATCHES/WARNINGS/ADVISORIES... MI...None. LM...None. && $$ UPDATE...WDM DISCUSSION...Ostuno AVIATION...WDM MARINE...Ostuno
Area Forecast Discussion
National Weather Service Lincoln IL
831 PM CDT Mon Aug 15 2022 .SYNOPSIS... Issued at 309 PM CDT Mon Aug 15 2022 Portions of central Illinois may receive some light rain on Tuesday morning. Otherwise, near to below normal high temperatures and cool low temperatures for mid-August are forecast for this week. Shower and thunderstorm chances return this weekend. && .UPDATE... Issued at 821 PM CDT Mon Aug 15 2022 A seasonably strong and deep corridor of FGen stretches from western IA into SW Illinois this hour per latest RAP and this forcing will remain fairly persistent and mostly stationary overnight. Meanwhile, 00Z KILX sounding continued to show a deep layer of dry air below roughly 500 mb (18kft) which is resulting in erosion of the leading edge of precip and plenty of virga where returns are noted on radar. Precipitation will continue on the cold side of the FGen band overnight with gradual top-down saturation allowing precip to reach the surface eventually, mainly west of a Galesburg to Effingham line. Precip amounts should remain light within the central Illinois forecast area, with up to around a quarter inch possible near portions of the lower Illinois River Valley. && .SHORT TERM...(This evening through Tuesday) ISSUED AT 309 PM CDT Mon Aug 15 2022 A surface ridge extending from Ontario southwestward into the upper Midwest is leading to northeast winds around 10 mph or so this afternoon. Visible satellite shows an extensive scattered- broken low cloud field over central Illinois, with higher clouds moving in from the northwest associated with the next approaching low. HRRR forecasts show a developing northwest-southeast band of strong warm advection at 850 mb from southeast NE into central MO from late tonight into early Tuesday morning. In addition, frontogenesis will be occurring along this band as a warm front strengthens. Associated perhaps with both frontogenetic and isentropic lift, an area of showers and thunderstorms is anticipated to develop on Tuesday morning. 12z CAMs have mostly shown this precipitation to be farther south than previous runs, with 24 hr HREF LPMM QPF in the 0.1-0.25" range over Morgan and Scott counties, lower to the northeast. NBM 90th percentile rainfall amounts in the southwest corner of the ILX CWA remain around 0.75", so though the probability of a more northward track has decreased it is still within the realm of possibility. Forecast soundings show minimal instability with thunder probabilities low (~5%). .LONG TERM...(Tuesday night through Monday) ISSUED AT 309 PM CDT Mon Aug 15 2022 The main forecast concern for the Tuesday night through Monday period centers around rain and thunderstorm chances for Friday through the weekend. Late in the week, ensemble member forecasts show a strong ridge persisting over the Pacific Northwest with a closed low developing within northerly flow somewhere over the upper Midwest. Ensemble clustering reveals some spread regarding the depth of this low, with about 80% of solutions on the shallower side and about 20% on the deeper side. Should a solution falling in the deeper cluster verify, instability may be a bit lower as drier air works in. Either way, shower and thunderstorm chances are anticipated to return to some degree from Friday into the weekend with 30-40% PoPs primarily in the afternoon/evening. Heavy rainfall and severe probabilities appear low at this time. && .AVIATION...(For the 00Z TAFS through 00Z Tuesday evening) Issued at 624 PM CDT Mon Aug 15 2022 A warm front will be in place from NW to SE Missouri this evening and overnight and will serve as the focus for thunderstorms. While some light showers may reach as far east as SPI, dry air and lack of instability will keep impacts from precip minimal and no thunder is expected this far east. NE winds will prevail most of the period but may become light and variable at times overnight. && .ILX WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Deubelbeiss SYNOPSIS...AAT SHORT TERM...AAT LONG TERM...AAT AVIATION...Deubelbeiss
Area Forecast Discussion
National Weather Service San Francisco Bay Area
750 PM PDT Mon Aug 15 2022 ...Significant Heat Far Inland Areas for Tomorrow... .SYNOPSIS...Gradual warming and drying continues as high pressure builds into the area from the east. Excessive heat concerns for the more interior locations expected tomorrow. Cooler conditions expected into next weekend. && of 02:30 PM PDT Monday...Temperatures across the area are currently in the 60s near the water with a compressed marine layer holding tight near the coast. Temperatures increase quickly further inland, with temps in the upper 80s and then 90s further inland. Temperatures will continue to rise through the afternoon with highs today reaching mid 90s for interior valleys and upper 90s further inland. Our usual hot spots in the interior East Bay could see temps reach low triple digits this afternoon. Hazy conditions and small concentrations of smoke from the Six Rivers Lightning Complex fire to advect southward into the Bay Area possible, as indicated per the High Resolution Rapid Refresh smoke model. Small concentrations of near surface smoke could create hazy conditions and impact air quality. This risk will be more concentrated towards the North Bay. Temperatures are still on track to be the warmest tomorrow afternoon. As such, the Heat Advisory is in effect from 11 AM to 8 PM Tuesday. An update from the previous discussion is that the southern portion of the Salinas Valley and interior Monterey County (including the Santa Lucia Mountains) were included in the Heat Advisory. Temperatures in the interior will likely reach triple digits with some areas in the farther interior near the Sac Valley reaching or exceeding 105 degF. The area most likely to see temps reach 105 are the interior portions of Contra Costa and Alameda counties as well as southern Monterey and San Benito counties. This results in a moderate HeatRisk for much of our area, with a high HeatRisk for locations bordering the Central Valley, including eastern portions of Contra Costa, Alameda, Santa Clara, and San Benito Counties. Higher elevations in the Santa Lucia mountain range are also highlighted as a high HeatRisk. This means there is a risk for heat- related illnesses to those who are sensitive to heat (in the moderate risk area), with this risk extending to most of the population in the high risk area. This concern is greatest for those without effective cooling and/or adequate hydration so be sure to check on your friends, neighbors, and outside workers during this heat event. Please use caution as temperatures will be dangerously hot in areas that are under High HeatRisk (such as interior East Bay). If planning to partake in outdoor activities, hydrate and take breaks often. If possible, seek AC and cooler conditions if further inland. For more specific information regarding where you are in terms of HeatRisk, check out or Looking beyond Tuesday, temperatures will continue to be toasty but start to gradually decrease. Subsequently, the HeatRisk on Wednesday has less aerial coverage in the "High" HeatRisk category, but a majority of our cwa remains under the "Moderate" risk. For now, the Heat Advisory is only in effect during the day and evening tomorrow, but stay tuned for upcoming forecasts to see if the Heat Advisory will be extended. However at this time, the Heat Advisory is only in effect for Tuesday. In addition, conditions will be hazy in the Bay Area and North Bay as small concentrations of smoke meander southward. A surge of monsoonal moisture in the midlevels of the atmosphere is expected to arrive tonight as well. There is some slight instability associated with this surge of moisture (100 to 200 J/kg of MUCAPE) but at this time stays confined to over the waters and near the coast. A slight chance for rain (15% PoPs) was added to the forecast over the waters Wednesday overnight. Confidence remains low on thunder chances Wednesday night, so not included in the forecast. We will continue to monitor for this chance. Into the longer term, heat concerns begin to diminish by Thursday and temperatures cool off to more seasonable temperatures by the weekend. && .AVIATION...As of 7:50 PM Monday... For the 00Z TAFs. The marine layer depth varies from 300 feet at Bodega Bay to 1,100 feet at Fort Ord per recent profiler data. It`s VFR across the cwa except for coastal stratus and fog /VLIFR-IFR/ which is patchy along San Mateo County to a more continuous coverage from southern Santa Cruz County southward along coastal Monterey County. The ACV-SFO pressure gradient has strengthened to 7.8 mb. Downsloping and drier northerly winds along with a compressed marine layer is resulting in a full erosion of stratus and fog along the coastal North Bay. HREF output shows a slow recovery in coastal stratus and fog /VLIFR-IFR/ tonight and Tuesday morning. Since the ACV-SFO pressure gradient and wind outweighs the onshore (2.3 mb) SFO-SAC pressure gradient and wind and the marine layer is forecast to stay compressed, expect very little if any stratus and fog intrusion into the Bay Area tonight and Tuesday morning. Wildfire smoke from the Six Rivers Lightning Complex over far northern California continues to arrive in our cwa on northwest winds. The HRRR vertically integrated smoke forecasts continue to show smoke arriving through most of Tuesday, then by late Tuesday and Wednesday winds shift to a southerly direction which should help disperse smoke layers. Vicinity of KSFO...VFR, west wind 15 to 25 knots decreasing to less than 10 knots late tonight and Tuesday morning. West wind returning and gusty to 20 knots Tuesday afternoon and evening. KSFO Bridge Approach...Similar to SFO. Monterey Bay...Stratus and fog /VLIFR-IFR/ tonight and Tuesday morning. Conditions lifting to VFR by late Tuesday morning and afternoon. Onshore winds 10 to 15 knots to mid to late evening, decreasing to around 5 knots overnight and Tuesday morning. Winds increasing to 10 to 15 knots Tuesday afternoon and evening. && of 01:42 PM PDT Monday...Strong northwesterly winds continuing across the coastal waters, with near-gale-force gusts possible in the northern outer waters. Steep, hazardous short period seas will build as a result. Winds diminish Tuesday afternoon through mid week. Light southwest swell from 14 to 16 seconds continues through the week. && .MTR WATCHES/WARNINGS/ADVISORIES... .Tngt...SCA...SF Bay until 9 PM SCA...Mry Bay until 9 PM SCA...Pt Reyes to Pigeon Pt 0-10 nm until 9 PM SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM SCA...Pt Arena to Pigeon Pt 10-60 nm SCA...Pt Arena to Pt Reyes 0-10 nm SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 3 AM && $$ PUBLIC FORECAST: McCorkle/SPM AVIATION: Canepa MARINE: Behringer Visit us at Follow us on Facebook, Twitter, and YouTube at:
National Weather Service Raleigh NC
930 PM EDT Mon Aug 15 2022 .SYNOPSIS... Low pressure will track southeast across the Carolinas through early Tuesday, then offshore later Tuesday and Tuesday night. && .NEAR TERM /THROUGH TONIGHT/... As of 930 PM Monday... Surface low pressure has situated itself over upstate SC as of 00z surface analysis creating predominately northeasterly low-level flow over central NC. Regional radar imagery shows all of the deeper convection over the NC/SC border while some lighter more isolated showers have developed over the Sandhills and Coastal Plain. Some isolated/scattered showers will remain possible through tonight as the H8 low, currently located over western NC based on recent RAP analysis, will slowly shift east-southeast tonight providing isentropic lift and WAA over a majority of central NC. Recent CAM guidance shows this solution as light showers begin to blossom over the area, however, overall coverage is still in question with the NAM showing the most widespread showers. In addition, this regime will promote low overcast across the area tonight which should linger through a majority of the day Tuesday. Lows, inherently, will be moderated by the cloud cover and only drop into the mid/upper 60s. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... As of 340 PM Monday... A mid-level cyclone developing over the nrn Mid-Atlantic today will remain in place through 12Z Wed, with associated low amplitude/ weakly-perturbed wly to wnwly flow directed across cntl NC. In the low levels and at the surface, an 850 mb low will track slowly east and across s-cntl and sern NC with a related band of frontogenesis through Tue evening, then offshore. The flow around that cyclone will also promote WAA/isentropic upglide across a wavy surface frontal zone that will sag sewd across the coastal Carolinas and atop high pressure that will ridge swwd across the Mid-Atlantic and interior Carolinas. Moist nely low level flow, and a thick saturated/overcast layer up through 700 mb, will result in cloudy conditions through the forecast period, along with mixed character light/rain showers that will focus along and north of the 850 mb low (ie. directly across cntl and ern NC) through Tue afternoon-evening. While additional rainfall amounts are expected to be light, generally a tenth to a third of an inch, the clouds and occasional rain will result in warm season CAD and minimal diurnal range in temperatures: well below normal (10-15 F) high temperatures in the 70s and lows in the 60s. && .LONG TERM /WEDNESDAY THROUGH MONDAY/... As of 210 PM Monday... An upper low over will sit over the Northeast Wed/Wed night, with the longwave trough extending south-southwest toward the Gulf Coast. The aforementioned low will lift to the north on Thu/Thu night as another northern stream low dives south from central Canada into the northern Plains/Western Great Lakes, where it will sit through Friday before gradually migrating eastward into the OH Valley over the weekend. The upper trough axis may fluctuate in its amplification Thu/Fri, before becoming anchored with the low over northern Plains/Western Great Lakes. By Monday, the low should be over the central/eastern Great Lakes, while the trough axis extends south-southwest, roughly along the Appalachians. At the surface, while a deepening low will drift northeast off the East Coast Wed/Thu, an area of low pressure will linger off the NC coast, while relatively high pressure dominates over central NC. Beyond Thu the surface pattern becomes a bit more variable and uncertain, but an inverted trough or relative area of low pressure is expected either along the Southeast/Carolina coast or inland over the Southeast and Carolinas. The driest days should be Wed/Thu while the low lingers over the Northeast, with increasing chances for showers/storms with the trough to the west. As for temperatures, highs could remain below normal through the weekend, while lows may creep up from below normal to just above normal. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 800 PM Monday... Numerous showers and storms continue to move along the NC/SC border and are expected to drift southeast, but some isolated storms may still impact FAY over the next couple hours. Otherwise widespread MVFR/IFR ceilings are expected to develop along with some showers possible at all TAF sites within the northeasterly low level surface flow. Conditions will be slow to improve to MVFR Tuesday morning with locations across the south, including FAY, having the potential to remain IFR through the remainder of the TAF period. Locations across southwest VA into northwest NC have a chance to fall to LIFR early Tuesday morning, but confidence was too low to introduce it at this time. -Swiggett Looking beyond 00z Wednesday, rain chances will decrease by Tue night-Wednesday, with mainly diurnal showers and a few thunderstorms as the front stalls south and east of the area. The continued moist NELY low-level flow associated with a weak warm season CAD event will result in high chances of sub-VFR ceilings Tuesday night and Wednesday night, that could be very slow to lift throughout the day, particularly at KINT and KGSO. Rain chances could increase late in the week as some upper disturbances move through the southern Mid- Atlantic. -MWS && .RAH WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...CBL NEAR TERM...Swiggett SHORT TERM...MWS LONG TERM...KC AVIATION...Swiggett/MWS
Area Forecast Discussion
National Weather Service Blacksburg VA
734 PM EDT Mon Aug 15 2022 .SYNOPSIS... Low pressure aloft will build toward the Mid-Atlantic through the week. This will result in a very unsettled weather pattern across the Mid- Atlantic and Appalachians. Rain and a few thunderstorms can be expected nearly every day. Temperatures will remain below normal all week. && .NEAR TERM /THROUGH TUESDAY/... As of 725 PM EDT Monday... Convection has diminished somewhat early this evening but still area of deep moisture flux convergence exists along wedge boundary from southeast WV into the NC Blue Ridge. With the upper low over the northern Mid-Atlantic, will likely see a few more vorts rotate across into the mountains overnight with showers scattered about. However with surface instability dwindling, showers should not be as excessive, so will let the flood watch expire at 8pm. Overnight looks to be cloudy and drizzly in the wedged areas similar to our cool season set up, with a few showers here and there. Fog will likely be patchy but seen area wide. Higher elevations could be stuck in dense fog so will monitor this. Previous discussion... Currently, weak surface low is centered over eastern Kentucky/far southwest Virginia with a stationary front roughly located from far southern West Virginia stretching across southern Virginia. This boundary is mainly evident by visible satellite where a thick stratus cloud deck is in place. Areas south of the stationary front have seen some breaks in cloud cover and have in turn warmed into the 70s, thus seeing RAP analyzed SBCAPE values of 1000-2000 J/kg as destabilization continues. Have already seen a few heavier rain clusters and embedded storms form within the last hour in the warm sector over northwest North Carolina. These newly formed clusters are within a zone where 25-45 kt effective bulk shear, marginally lapse rates and modest MLCAPE overlap. This area should (i.e. southwest Virginia into North Carolina) continue to promote at least a few storm clusters through the afternoon/evening, capable of producing strong winds, heavy rainfall, and some localized instances of hail. It is also worth mentioning that while still very low, the tornado threat is not zero, especially since we are dealing with a wedge/stationary boundary. Severe threat likely to subside by this evening with maybe some lingering thunderstorms in the far southern portions of the CWA. Rain showers and drizzle will continue overnight and fairly widespread fog settles in as the wedge strengthens and builds south. Cool air wedge likely to remain solidly in place for Tuesday, thus the cloudy, cool, and rainy conditions will continue. Went a bit lower on guidance for tomorrow for high temperatures with upper 60s to low 70s the general theme. With less instability, thinking thunderstorm threat will remain much lower so only kept mention of storms along and south of the VA/NC for an isolated chance. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 110 PM EDT Monday... Cooler than normal temperatures expected... The short term portion of the forecast will be dominated by a surface wedge of high pressure. Aloft, an anomalously deep upper level trof (1-2 standard deviations stronger than normal will reside over the northeast U.S. on Wednesday before lifting on Thursday. While there is high confidence that temperatures will be below normal, there is considerable spread in the NBM regarding the temperature values Wednesday and Thursday, leading to lower than average confidence. Went a couple of degrees lower than the NBM guidance considering the magnitude of the upper level trof and associated sfc wedge, but the amount of cloud cover will be key in temperature forecast. On Wednesday, an impressive 100+ kt upper level jet max sweeps over our region and the southern portion of our forecast area will reside under the RR quad of this jet coincident with increasing upper level divergence. Despite the deeper moisture remaining well south of our area, forecast soundings showing saturation below 10K ft combined with this forcing should generate scattered showers, especially across the NC mountains. As the upper level trof and jet max lift, chances for precipitation diminish on Thursday. The exception may be across the east facing slopes of the Blue Ridge, and especially the southern Blue Ridge, where a weak upslope flow and lingering moisture below 600mb will continue to spawn scattered showers/areas of rain. && .LONG TERM /FRIDAY THROUGH MONDAY/... As of 1215 PM EDT Monday... Chances for showers and storms increases for the weekend into early next week... The long range deterministic models are in general agreement that a the long term period begins with a broad upper level trof covering the eastern U.S. with an upper level low digging south into the Upper Mississippi Valley, with the trof axis shifting east by Monday. The WPC cluster analysis output shows decreasing confidence with time with regard to the magnitude and timing of this trof late in the weekend into Monday, with the ensemble mean suggesting the trof weakens similar to the 00Z/15 GFS or Canadian runs. As this upper trof approaches the low level wedge in place weakens with the GEFS 31-member ensemble output showing the probabilities of CAPES exceeding 1000 j/kg increasing each day from Saturday through Monday. With PWAT values also increasing, increased POPS accordingly. Temperatures will moderate as the NCEP Ensemble mean shows a fairly strong signal of below normal 850mb temps on Friday, gradually warming to above normal by the weekend. The potential for mostly cloudy to cloudy skies, however, will likely keep temps near normal late in the period. && .AVIATION /00Z TUESDAY THROUGH SATURDAY/... As of 730 PM EDT Monday... Poor flying conditions expected for most of the taf period, as wedge and scattered showers hold in low level moisture. Shower chances higher in the LWB/BLF/BCB areas this evening and perhaps ROA but overnight expect showers to be widely scattered, with drizzle anticipated in the wedged areas at times, along with cigs below 1kft and vsbys in the 1-4sm range, sinking to less than 1sm higher elevations, so BLF could see this. Should see low cigs/vsbys improve slowly Tuesday though may have sub-VFR into early afternoon across the ROA-LYH corridor. More shower scattered about in the afternoon but not enough to mention in the tafs. .Extended Aviation Discussion... As the upper low retrogrades to the west through the week, precipitation will tend to become more convective in nature. This will result in increased periods of VFR during the daytime into the evening with overnight potential for dense fog at LWB/BCB and other areas that may have rain. Bottom line is that the entire week will remain unsettled with shower and thunderstorm chances all week. && .RNK WATCHES/WARNINGS/ADVISORIES... VA...Flood Watch until 8 PM EDT this evening for VAZ007-010-011-018- 019-023. NC...None. WV...Flood Watch until 8 PM EDT this evening for WVZ042>044-507-508. && $$ SYNOPSIS...BMG NEAR TERM...BMG/WP SHORT TERM...PH LONG TERM...PH AVIATION...BMG/WP
Area Forecast Discussion
National Weather Service Topeka KS
937 PM CDT Mon Aug 15 2022 .UPDATE... Issued at 937 PM CDT Mon Aug 15 2022 Showers and thunderstorms have developed across southern NEB a few hours sooner than the models have and it looks like the HRRR is still trying to catch up with reality. So have increased POPs and bring precip into the northern parts of the forecast area over the next hour or two. Models show surface based instability continuing to diminish as the boundary layer cools, and forecast soundings from the RAP suggest only a few hundred J/kg of elevated instability across the northern counties. Effective shear analysis from SPC shows 40KT to 50KT are still available so there may be an isolated intense updraft that could produce some damaging winds. Freezing levels around 14KFT imply the updraft would have to be really intense with 50dBz levels approaching 40KFT for hail. So with the marginal instability, large hail appears to be a low probability. && .DISCUSSION... Issued at 254 PM CDT Mon Aug 15 2022 Key Points: - Cold front moves through tonight, chance of showers/storms into tomorrow - Much cooler weather arrives for tomorrow, sticks around through the weekend A current look at surface observations across the area shows the key players in our much awaited transition to cooler weather. A nearly stationary front is in place across eastern Kansas, stretching eastward from a 1009 mb low over the southern Kansas/Colorado border. High pressure to the north is keeping easterly flow in place to the north of the boundary, with widespread clouds and precipitation developing just across the state line into Nebraska. So there is quite a contrast in temperatures on either side of the front. Temperatures near the Nebraska border are in the upper 70s and low 80s, while along and south of I-70 temperatures have climbed into the 90s and even low 100s amidst southerly winds and strong sunshine. This afternoon and evening, will still need to watch out for an isolated storm or two developing along the front this afternoon and evening, along a line from Concordia to Burlington. Shear 30-40 kts and 2000-3000 J/kg of MUCAPE could support a strong to severe storms if any develop. However despite a lack of significant CIN, it remains more likely that nothing develops in this area as the better upper support from the main shortwave will remain to the north. The better chance for showers and a few thunderstorms will occur late this evening and tomorrow morning as the surface low to the west shifts southeast, dragging the cold front south through the remainder of the area. The axis of heaviest precipitation does look likely to stay north and east of the area, given the track of the stronger mid-level vorticity to the north. So total rainfall should be highest in far northeast Kansas, at perhaps around a half inch, decreasing with southwestward extent. Clouds and occasional showers will stick around for much of the day tomorrow, keeping temperatures well below average. Highs should stay in the 70s for most, perhaps even 60s in a few spots if thick cloud cover can stick around through the afternoon. Wednesday through the weekend, the cooler than average weather sticks around. An additional upper low drops south into the main longwave trough late week, reinforcing the mean trough and keeping the overall pattern in place. So highs should generally stay in the 80s with lows in the low/mid 60s, with just some minor variations depending on the timing of individual shortwaves. High pressure initially keeps things dry Wednesday and Thursday, with rain chances increasing Friday into Saturday as the upper low moves in. && .AVIATION...(For the 00Z TAFS through 00Z Wednesday) Issued at 547 PM CDT Mon Aug 15 2022 Models show the main synoptic scale forcing for showers and storms moving across northeast KS after 06Z. Think the convection near KCNK is more diurnally driven. So it may still be some time before precip impacts the terminals. The models are in agreement that at least MVFR CIGS will move in behind the front and could last through much if not all day Tuesday. There could even be a period of IFR CIGS as the front passes. For now will use the model consensus for timing the lower clouds and the CAMs for a VCSH at the terminals. Coverage of storms from the CAMs appears to remain scattered enough to limit confidence in a prevailing SHRA. And instability looks to be fairly limited for widespread TS. && .TOP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ UPDATE...Wolters DISCUSSION...Reese AVIATION...Wolters